Aquatic Environment
Restoring The Avoca River
Report to the Eastern Regional Fisheries Board, Dublin by University of Newcastle
Restoring the Avoca River: an integrated
social/technical scoping study of acid mine
drainage remediation options.
Aidan Doyle
Paul L Younger
Catherine J Gandy
Richard Coulton
(Unipure Europe Ltd)
University of Newcastle
(With additional information by
Fisheries personnel)
University of Newcastle University of Newcastle Restoring the A Restoring
the Avoca River voca River
EXECUTIVE SUMMARY
1. Introduction
1.1 Background
1.2 Objectives of Study
1.3 Previous Work
1.4 Acknowledgements
2. The Avoca Mine Site and Surrounding
Area
2.1 Location and Description
2.2 Geology
2.3 Hydrogeology
2.4 Mine wastes, the mined landscape
and concepts of remediation
2.4.1 EU LIFE Project approach to the heaps
2.5 Catchment characteristics – Fisheries
context
2.6 Miscellaneous other economic and location
considerations
2.6.1.1 Arklow and oysters
2.6.2 The former IFI factory
2.6.3 Tourist attractions
2.7 Catchment management planning
Maps 1–4
3. Stakeholder Analysis and the Case for
Action
3.1 Ways of Understanding
3.2 Stakeholder analysis. What and Why?
3.3 Who are the stakeholders?
3.4 Stakeholders Identified
3.4.1 Primary Stakeholders
3.4.2 Secondary Stakeholders (Key Stakeholders)
3.5 Stakeholders who responded to this
study
3.5.1 Local Residents
3.5.2 VADA
3.5.3 Anglers
3.5.4 Hospitality Businesses
3.5.5 Aquaculture
3.5.6 Wicklow County Council
3.5.6.1 Local Authority stated commitment
3.5.6.2 Projects, Proposals and Ownership
3.5.6.3 Other water contamination concerns
in the lower catchment
3.5.6.4 Economic Development
3.5.7 The Environmental Protection Agency
(EPA)
3.5.8 Department of Communications and Marine
and Natural Resources (DCMNR)
3.5.9 The Central and Eastern Regional Fisheries
Boards
3.5.10 Dúchas
3.5.11 East Coast and Midlands Tourism
3.5.12 Mining Heritage Trust of Ireland (MHTI)
3.6 Root definitions. The concerns and aspirations
of stakeholders and where they concurr
4. Data sources and quality
4.1 List of data provided by ERFB and other
contacts
4.2 Creation of database
4.3 Quality and usefulness of data from
disparate sources
5. Hydrochemistry
5.1 Principles of calculating acidity
from pH and metals concentrations
5.2 Mine water discharges
Photographs
5.3 Surface water sampling sites
6. Flow data: gauged and estimated
6.1 Avoca River
6.2 Deep Adit
6.3 Ballymurtagh Adit
7. Biological effects of mine water pollution
on Avoca River
7.1 Effects of mine water pollution on
the Avoca River – fish kills
7.2 Fish stock surveys 2001/2002
7.3 Future work on biology of Avoca River
to facilitate future demonstration
of the benefits of remediation
7.4 Future potential of catchment
Maps and Photographs
8. Remedial options for the Avoca mine
waters
8.1 Definition of design flows and design
contaminant loadings
8.2 Availability of land for treatment systems
8.3 Additional assumptions lying behind definition
of treatment options
8.4 Option 1: Do nothing
8.5 Option 2: Completely active treatment
8.6 Option 3: Completely passive treatment
8.7 Option 4: Hybrid passive-active system
8.8 Preferred option
8.9 Further data requirements to support
confident
design and costing of preferred option
8.10 Towards robust cost-benefit analysis
of the case for treatment
9. Conclusions and Recommendations
9.1 Future work in developing stakeholder
engagement
9.2 Identifying and securing funding
9.3 Site survey information requirements
9.4 Hydrological and hydrochemical data
collection
9.5 Proposed forward programme
10. References
11. Appendices
EXECUTIVE SUMMARY
A scoping study has been undertaken on behalf of the Eastern Regional Fisheries
Board (ERFB) of the Republic of Ireland to identify and develop outline costings
for remediation measures which can restore the Avoca River to the status of
a salmonid fishery. The focus of the study is the provision of alternatives
on remediation measures that are required to reduce the levels of acidic mine
drainage entering the Avoca River from the abandoned copper mines in the area.
The lower reaches of the Avoca River is the most polluted river in Ireland.
It has received toxic acid mine leachate and effluent for over 200 years and
there is a perception that the catchment is so compromised that it has a limited
fishery value. However, electrofishing surveys carried out by the Fisheries
Boards in the Avoca River catchment in 2002 indicate that salmon and trout
fish stocks are present in the system and that the system has excellent potential
as a recreational salmon and sea trout fishery.
The study has pursued the following key objectives:
• Collation of all previous data and reports concerning the site, entering
the information into a purpose-written MSACCESS
database
• Undertaking a preliminary (but fairly comprehensive) stakeholder analysis,
in order to identify the key socioeconomic
hurdles which need to be overcome if the river is to be restored to salmonid
fishery status
• Analysis of available data (supplemented with some further data collected
on site) in order to derive design
parameters for possible remediation options
• Proposal of alternative remedial options and provision of costings
for those which could achieve the desired objectives, given constraints of
available land etc.
An extremely promising community of interest exists in the catchment, which
is keen to see the polluting discharges abated, and the salmonid status of
the Avoca River restored. The basis exists for the development of a broadly-based
partnership with the necessary momentum to secure funding, develop a treatment
solution and ensure long-term maintenance of the necessary
facilities, rooted in the local community. A number of technical options were
considered in the study, including “do nothing”, a pipe line to
the sea, hydrogeological and revegetation approaches, passive treatment, active
treatment and hybrid passive-active treatment. The preferred option is
unequivocally active treatment. If this were combined with a polishing wetland,
some of the ancillary benefits of the passive treatment option could be added
to the active treatment approach, at relatively modest additional cost. Before
such a solution can be designed in detail, there is a need for a further programme
of work with the following components:
• a minimum one year programme of hydrological and hydrochemical monitoring
(hopefully implemented by
ERFB) to yield a complete, synchronous data set
• site surveys of the parcels of land suitable for installation of treatment
works
• on-site treatability trials to confirm treatment design parameters
• cost-benefit analysis of the case for treatment
• development of an inclusive partnership, spanning local and national
governmental agencies, local residents and relevant elements of the private
sector
In conclusion, with the strong level of partnership between the stakeholders
and the scientific knowledge to develop a suitable treatment system for the
acid mine drainage from the Avoca River, there is a promising future for the
Avoca catchment. This river has the potential to be restored as a significant
state asset. In terms of its recreational angling potential it could generate
at least €750,000 per annum, (Indecon, 2003). The value of this river
once restored would be enormous to the local community, bringing economic,
tourism, social and cultural benefits.
1. Introduction
1.1 Background
Pollution of the Avoca River by mine water discharging from drainage adits
of abandoned copper and sulphur mines at Avoca, in County Wicklow, Ireland,
is a long-recognised problem. The river is severely affected by the mine water
and is considered by the EPA to be the most severely polluted stretch of river
in Ireland. This report is the fruit of a scoping study which was commissioned
by the Eastern Regional Fisheries Board (ERFB) of the Republic of Ireland
(as coordinating partner of a broad-ranging stakeholder group) to identify
and develop outline costings for remediation
measures which can restore the Avoca River to the status of a salmonid fishery.
1.2 Objectives and methods of study
1.2.1 Scope of work and key objectives
The purpose of this study was defined by ERFB as follows: “to provide
a number of alternatives on remediation measures that are required to reduce
the levels of AMD entering the Avoca River. The specific study area is from
White’s Bridge (East Avoca) downstream to the estuary of the river in
Arklow”.To meet this purpose, a number of key objectives have been pursued,
as follows:
• to collate all previous data and reports concerning the site, collating
the information into an MSACCESS database
• to undertake a preliminary (but fairly comprehensive) stakeholder analysis,
in order to identify the key socio-economic hurdles which need to be overcome
if the river is to be restored to salmonid fishery status
• to analyse available data (supplemented with some further data collected
on site) in order to derive
design parameters for possible remediation options
• to propose alternative remedial options and provide costings for those
which could achieve the desired objectives, given constraints of available
land etc.
1.2.2 Methodology: scientific and engineering aspects
In terms of scientific and engineering work, the study reported here was almost
wholly a desk study, as requested by the ERFB. A number of site visits helped
in gaining an appreciation of the study area and its problems, and also facilitated
collection of some targeted water samples which permitted resolution of some
issues arising from pre-existing data. Most of the analysis has used standard
hydrochemical and hydrological techniques, implemented using spreadsheet
technology. The technical basis for the analyses performed is detailed by
Younger et al. (2002).
1.2.3 Methodology: social perspectives
We are combining technical evaluation, leading to remediation of the mine
water, with an enquiry into stakeholders’ understanding and potential
engagement. Local knowledge and scientific information should be combined
in order to solve practical problems (see for example Ortiz 1999). Through
stakeholder analysis we investigate ways of combining technologies with local
peoples’ intimate knowledge and sense of place. “Knowledge that
aspires to become applicable
or be of practical use has to be developed jointly with the users of the knowledge
…” (Brulin 2001.441). To develop tools for informed management decisions
and focussed sustainable intervention we consider all of the issues at stake.
Collaboration amongst mine water scientists, fisheries personnel, geologists,
resident communities and others is aimed at continued data collection and
the development of a management regime that will prove culturally suitable
for resident
community ownership. The scope of the projects, our minimum locus of agreement,
is defined by the stakeholders.
Groups and individuals agree on what our proposals are rather than merely
their own individual goals. The ultimate aim is the development of a partnership
in terms of tactics (specific application) and strategy (medium and long term
developments) (Amezaga and O’Connell 1998). This report is intended to
provide the foundation for such a partnership. Social fieldwork has been conducted
following appropriate research protocols for working in local communities.
Respondents are made fully aware of the purpose (and consequences) of the
enquiry. Data was acquired at a personal
conversational level from open-ended questions. The project board provided
advice and contact details of all groups and individuals.
1.3 Previous Work
There has been a significant amount of previous work carried out on the Avoca
Mines area, addressing:
• the geology and hydrogeology of the area (e.g. Flynn, 1994; O’Suilleabhain,
1996; Gallagher and O’Connor, 1997)
• the characterisation of the principal polluted discharges and their
impacts on the Avoca River (Gray, 1994a,b, 1995a,b)
• reviews and pilot-scale trials of possible remediation methods applicable
in this setting (Gallagher et al., 1998; Prescott and Kilkenny, 1997; Kilkenny
and Good, 1998), which were principally funded through an EU LIFE project.
While all of the above studies have yielded data which are central to the
interpretations and recommendations presented in this report (as will become
clear in later sections), the latter trials are particularly pertinent to
the focus of our work. Trials undertaken at the site have included the use
of waste magnesium hydroxide slurry from the Premier Periclase factory, where
it is used to remove suspended solids and silica from seawater. Whilst the
use of waste magnesium hydroxide to treat the Avoca mine water can be perceived
as environmentally beneficial, it is important to review the
implication of using this material on the overall operation of the mine water
plant before deciding whether to use magnesium hydroxide instead of other
reagents. This review is implemented in Section 8.2. In addition, trials in
West Avoca demonstrated the use of sewage sludge as a soil amendment for promoting
revegetation of acid-generating metalliferous spoil. While revegetation was
successfully achieved, it does not appear that this will in itself hinder
infiltration sufficiently to suppress the generation of acidic leachates within
the spoil heaps. (This is a common finding in similar revegetation studies
elsewhere; Younger et al. 2002).
Beyond Avoca, there is of course a vast amount of experience worldwide in
the characterisation and remediation of polluted mine drainage. The most comprehensive
synthesis on this topic to date (Younger et al. 2002) demonstrates that the
technology is available to fully remediate the Avoca discharges. A few brief
examples from other countries where similar high-sulphur orebodies have also
been mined for many centuries suffices to demonstrate the feasibility of
remediation at Avoca.
Example 1 - Wheal Jane tin/zinc mine, Cornwall, UK.
Wheal Jane was the last of a large number of mines which once worked the tin
and zinc bearing lodes of the Carnon Valley (between Truro and Falmouth, Cornwall).
After the mine was abandoned in March 1991, the workings flooded to
river level and gave rise to a substantial discharge of acidic, metalliferous
waters to the Carnon River. A flow of contaminated water ranging between 90
and 300 l/s has continued ever since, prompting the development of an extensive
programme of remedial measures. The history of these developments has been
recently recorded by Younger (2002). The key points of relevance to Avoca
are:
(i) For an acidic metal mine discharge of this type, with multiple ecotoxic
metals and highly elevated acidity coupled with a high flow rate (much higher
than at Avoca), only active treatment was capable of achieving treatment objectives.
A temporary treatment plant was operated from 1992-2000, based on conventional
lime dosing, flocculation, and sedimentation technology. The long-term treatment
commissioned at Wheal Jane in the autumn of 2000 is a state-of-the-art active
treatment plant, comprising a high-density sludge alkali dosing plant, designed
and commissioned by Unipure Environmental. This plant is equipped to treat
up to 350 l/s of mine water, and is achieving the major improvements in water
quality required by the regulators. During its first full winter of operation,
the Unipure plant successfully treated a total of 4.4 Mm3 of water, removing
a total of about 1000
tonnes of metal which would otherwise have been discharged to the Carnon River.
(ii) Early in the search for a long-term treatment strategy, the NRA undertook
to evaluate the possibility of developing a wetland-based passive treatment
solution for the Wheal Jane site. The Wheal Jane Pilot Passive Treatment Plant
(PPTP) has generated large volumes of interesting data. However, with the
benefit of hindsight, it is now clear
that the PPTP suffered from an unfortunate design flaw: it was essentially
configured “back-to-front”, inasmuch as acid-generating aerobic
processes were sited upstream from the crucial alkalinity-generating anaerobic
processes. Useful insights into the capability of passive processes to cope
with extreme mine water discharges were nevertheless gained.
Example 2 - Norwegian copper / zinc mines (information provided by D Banks)
Treatment of copper / zinc - containing mine water in Norway has been achieved
using conventional active treatment (alkali dosing), electrolysis and pilot-scale
trial wetlands. Chemical treatment and electrolysis have been employed at
Kongens Gruve and Folldal Mines to reclaim copper metal from mine water. The
procedure is cited to have a 99 % removal rate for copper (albeit the last
10% of removal is estimated to be as expensive as the first 90%). Three pilot-scale
trials have been carried out using wetlands to treat runoff from copper /
zinc mines in Norway. One of these, at Storwartz
Mine, consisted of 6 tanks containing (in order): an anoxic stripping cell;
crushed limestone; anaerobic wetland (two tanks); aerobic cell; zeolite polishing
cell. Copper was removed from the water at an average rate of79 % but zinc
proved more difficult to remove, with an average rate of only 37%. Iron was
readily removed at an average rate of 75% with the most effective removal
occurring in the tank containing crushed limestone. Kongens Mine is very similar
to Avoca, in
that surface runoff (including runoff from a number of overlying mine waste
tips) drains rapidly down through voids and fractures into the mine complex.
In 1999, a wetland system was constructed to treat the water, consisting of
an anoxic limestone basin, four anaerobic compost basins and a final aerobic
lagoon. The system removed 89–98% copper and 80- 93% zinc. This system
was then replaced in August 2002 by a system comprising a single anaerobic
compost basin. It is
too early to comment on the efficacy of the new basin but initial results
are somewhat disappointing with only 15-20% removal of copper.
In summary, experience worldwide (Younger et al. 2002) shows that passive
treatment is feasible for waters such as those at Avoca, provided flows are
modest. Where flows are high (> 10 l/s) the acidity loadings are likely
to be such that active treatment methods based on alkali dosing are most likely
to be required.
1.4 Acknowledgements
In the development of understanding of background issues and problems associated
with the project it has been necessary to meet with many people. We have met
a variety of public and private stakeholders: officers with statutory responsibility,
anglers, former miners, business people and interested local residents - at
a variety of locations: office, hotel, fish farm, fishery, boathouse, public
house, and at the mine sites. A clear indication of the goodwill of many of
the respondents is
that time has been taken off work to meet with us in the winter weather. In
response to our questions we have been met with openness and kindness. Answers
to our open ended questions have been essentially informal, though nevertheless
focussed. We extend our warmest thanks to all respondents / participants.
We are particularly grateful to the following organisations and individuals
who have contributed significantly to the development of this report:
Annamoe Trout Fisheries; Wesley Atkinson; Aughrim Anglers’ Association;
Ned Bayley; Charlie Berdon; Michael Brady; Brian Breslin; Derek Byrne; Donnachadh
Byrne; Dudley Byrne; Patrick Casey; Sean Casey; The Central Fisheries Board;
Kevin Clabby; Tom Clinton; Coillte; County Wicklow Film Commission; Nick Coy;
Dr Martin Critchley; Gareth De Brun; Karen Delanty; Department of Communications,
Marine and Natural Resources, Exploration
and Mining Division; Vibeke Dikjman; Pat Doherty; Brendan Driver; Colm Driver;
Tom Driver; DUCHAS; East Coast and Midlands Tourism; Eastern Regional Fisheries
Board; Paddy Egan; Michael Enright; Environmental Protection Agency; ERA MAPTEC
Ltd; Jim Fagan; Padraic Fitzpatrick; Francis Fanning; Loreto Farrell; Gerry
Flood; Paul
Gallagher; Piers Gardiner; Geological Survey of Ireland, Groundwater Section;
Billy Hannon; David Harrington; IDAS; IFI; IFA; Coran Kelly; Martin Kelly;
Nicky Kerwin; Fred Lochlain; Tom Lyng; Michael Lynham; Lord Meath; Peadar
McArdle; Michael McEvoy; Alan McGurdy; Peter Moore; John Morris; Brian Nally;
Jim O’Brien; Dr Pat O’Connor; Tony O’Neill; Seoirce O’Toole;
Lynn Paterson; Steffen Petersen; Rathdrum Anglers Association; George Reynolds;
Dr William Roche; ‘The Meetings’ public house, Avoca; Vale of Avoca
Development Association; Wicklow Anglers
Association; Wicklow County Council; Geoff Wright; Donal Young.
We are grateful to the ERFB for a chance to present them with our ‘work
in progress’ report in December, and for their unstinting hospitality
on that occasion, as indeed at other times.
We wish to express our particular thanks for their extra organisational effort
to Peter Driver and Stewart McGrane; and to Andy and Marie Merrigan for the
significant contribution of their time, effort and understanding. We acknowledge
the unreserved dedication of Josie Mahon to the execution of the stakeholder
engagement, and indeed the whole programme of research. The enthusiasm of
the Blackrock ERFB staff has been exemplary, far surpassing the ordinary expectations
of the delivery of duty. Thank you once again to all. CFB & ERFB staff
have extensively provisioned this report with data relating to fish stocks,
fish kills, etc.
External technical review comments have been provided by Bruce Misstear of
Trinity College Dublin and David Banks of Holymoor Consulting Ltd. (Unfortunately
some participants were unable to respond).
2. The Avoca Mine Site and Surrounding
Area
2.1 Location and Description
The Avoca Mines are located within the Avoca River Catchment which covers
an area of 650 km2. The East and West
Avoca Mines are separated by the Avoca River, which flows through the Vale
of Avoca, a noted beauty spot and tourist
attraction. To the north of the mines, the Avoca River is formed (at the “Meeting
of the Waters”, famed in verse) by the
confluence of the Avonbeg and Avonmore Rivers while, 6.5 km to the south,
it is joined by the Aughrim River whence
it flows a further 7.5km to the sea (which it meets at the fishing port of
Arklow). Several smaller tributaries join the Avoca
River close to the mine water discharges, including the suggestively-named
Sulphur Brook to the south of East Avoca
Mines, and the Vale View and Red Road (again, a name suggestive of long-standing
acid drainage) streams to the north
and south respectively of West Avoca Mines. (see map 1, map 2 & photo
1 pages 13,14 & 33)
2.2 Geology
Southeast Ireland lies within the Caledonian-Appalachian orogenic belt, to
the south of the Iapetus Suture (a tectonic line which marks the Ordovician
collision zone between two palaeo-continents which corresponded roughly to
the present North America and Europe). The mineralisation at Avoca lies within
the Avoca Formation, a sequence of 455 million year old Ordovician volcanic
and sedimentary rocks formed in response to the Iapetus closure. The Avoca
Formation forms part of the Duncannon Group (Gallagher & O’Connor,
1997). (see map 3 page 15) The outcrop pattern of the Avoca Formation is lenticular
in shape, being 2-4 km wide by 15 km long, with the long axis of the outcrop
following the regional NE-SW Caledonian trend. The Avoca Formation can be
subdivided into three members:
1. The oldest unit is the Castlehoward Member which is confined
to the river valley and the area adjoining this to
the northeast. This member is 450 to 1200 m thick and comprises sericitic
tuffs with felsic horizons.
2. The Kilcashel Member (700 to 1050 m thick) underlies the
central part of the Avoca district and consists of
altered, silicified tuffs notable for their high chlorite content.
3. The youngest unit is the Tigroney Member which is 350
to 1800 m thick and is dominated by sericitic lithic and crystal tuffs and
felsites with some chloritic crystal tuffs. The bedrock lithologies in the
Avoca Area have undergone a common structural evolution. The Avoca Formation
and its
enclosing sediments join and dip towards the southeast. A set of normal faults
run NW-SE and another NNE-SSW, some of which cut through all members of the
formation. The mineralisation at Avoca occurs as massive and stringer sulphides
and is regarded as volcanogenic in origin (i.e.
seafloor volcanic-exhalative deposits, formed by ancient equivalents of ‘black
smoker’ submarine springs seen today at mid-ocean spreading ridges).
The main ore zones at the Avoca Mines occur at the top of the Kilcashel Member
at its contact with the Tigroney Member, where a few metres thickness of banded
sulphides occur. Pyrite makes up over 95 % of the ore, and while this is typically
regarded as an uneconomic gangue in many similar orebodies, at Avoca it was
extensively worked as an ore for sulphuric acid production. The other major
ore minerals in the Avoca deposits are chalcopyrite, sphalerite and galena,
providing copper, zinc and lead respectively. Minor minerals, such as arsenopyrite,
tetrahedrite and bismuthinite, as well as some gold and silver, are also present.
A detailed account of economic geology of the catchment and a brief history
of the mine sites are given in appendices I and II.
2.3 Hydrogeology
There is no doubt that the dominant hydrogeological features of the study
area are the flooded mine voids themselves, which collect drainage from a
large volume of ground and old workings and deliver it to the Avoca River
in the form of major point discharges (from the portals of the Ballymurtagh
Adit and the Deep Adit). In common with many other mining areas, however,
the internal dynamics of the flooded mine void system are poorly characterised.
As part of a study
carried out by the Geological Survey of Ireland (GSI) in 1995 the drilling
of 5 boreholes took place in the area surrounding Avoca mines, which complemented
54 pre-existing boreholes which were suitable for groundwater level monitoring.
However, most of these boreholes were drilled into the surrounding crystalline
bedrock rather than the mine voids so are of little help in assessing the
hydrogeology of the flooded mine void system. The permeability of the bedrock
proved to be very low and it was deduced that groundwater movement occurs
largely through fissures and fractures (some of which may well have been induced
by mine void caving). Specific yield in the volcanic rocks is low, resulting
in relatively large fluctuations in water level following small variations
in aquifer recharge and discharge. This is accentuated by the fact that sub-soils
(drift deposits) are thin over most of the area. (see map 4 page 16)
Groundwater levels were found to be generally between 5 and 15 m below ground
level and did not tend to fluctuate greatly. However, a significant head difference
exists between the bedrock and the enclosed mine voids, with water levels
outside the mined features being substantially higher (Flynn, 1994). This
head difference causes groundwater to flow into the mined zone, confirmed
by the occurrence of seepage faces flowing into the opencast mines from adjacent
areas. This is consistent with the concept of the mine voids acting as ‘master
drains’ for this area.
In summary, virtually all of the groundwater in the area can be assumed to
ultimately discharge into the Avoca River, principally through the network
of shafts and adits to discharge into the Avoca River via the Deep Adit (for
the East Avoca Mines) and the Ballymurtagh Adit (for the West Avoca Mines).
Small amounts of water (generally too small to accurately measure) also discharge
to the river as diffuse flow and as minor adit discharges (Flynn, 1994).
2.4 Mine wastes, the mined
landscape and concepts of remediation
The East Avoca mine site includes colourful ‘spoil’ heaps: the product
of old and recent mining activities. Gallagher et al. (1998, p. 10) note their
composition, distribution, volume and appearance. They estimate the total
volume of spoil in East Avoca as 1,035,809m3, with Mount Platt accounting
for 69% of the total. The volume of surface spoil heaps in West Avoca is estimated
as 422,278m3. The mine sites cover 63 ha, and the spoil heaps comprise some
40% of this area, i.e. around 26 ha, with the open pits a further 14%, or
9ha. They proffer the qualitative observation that the appearance of the mine
site is “dominated by the barren red-brown spoil that covers its surface
and contrasts with the verdant surroundings of the Avoca valley” (Gallagher
et al. 1998, p.10). They note that weathering leaches a significant portion
of the metal content of the heaps. Some heaps were reclaimed in the 1970s,
by means of re-mining since they were then of ore grade. In the 18th and 19th
centuries ore was dressed manually on the ground. Large piles of low grade
ore
‘cobbings’ were created through this process. Mount Platt, a single
large heap, was produced in the 1970s from large volumes of spoil from the
Cronebane open pit. The current spoil heaps are heterogeneous in composition
and sulphide grade. The dominant surface texture, a fine clayey matrix, provides
a resistance to permeability within many of the heaps.
2.4.1 EU LIFE Project approach to the
heaps
The EU LIFE project addressed means of revegetating the heaps, trialling the
use of windrow-composted sewage sludge. Such approaches are of course nothing
new: many organic materials can be used to develop sufficient moisture retention
and metal-sorption capacity in mine spoils that they will support plant growth.
From the mine water remediation perspective, however, the over-riding concern
remains the bulk permeability of the mine wastes, which is rarely reduced
by the development of root channels and other macropores associated with growing
plants. Hence infiltration of water into the material still occurs and gives
rise to contaminated leachate, which typically sinks to a perched water table
within the spoil and migrates to discharge elsewhere, away from the plant
root zone. Not surprisingly, therefore, the EU LIFE project report found that
even under pine or birch cover there is a high level of background contaminant
transport in the
spoil by infiltrating rainwater. The EU LIFE project’s proposed regrading
of open pits to replicate natural slopes are seen as symptoms of a general
pervading attitude that the mine areas are problems rather than opportunities.
As Gallagher et al. (1998, p. 22) have noted:
“Whether the visual impact of mining is a negative environmental impact
is largely a matter of aesthetics…”. However, they go on to note
the scientific interest of the heaps and open pits as being “as worthy
of preservation as any historical building or artefact”.
The scenery afforded by the mine sites is subject of significant judgmental
bias. Parkes (1999) has noted that the mining landscape is “powerful
[in its] own right” adding that many mine sites in the UK are protected
as Sites of Special Scientific Interest (SSSIs) as a consequence of their
uniqueness. Parkes expresses the need to look at these sites in alternative
ways.
“I see not eyesores, but awesome pits, symbolic of so many things. I
see
not a scarred landscape, but a history - a visible record of human
endeavours - a mine heritage landscape. With more time, it would be
possible to find numerous literary quotations to illustrate how the
of mined areas becomes suffused into people’s consciousness,
and becomes part of their local identity”.
Furthermore the mine sites have developed new ecosystems; naturally occurring
remediation via metallophytic floral uptake presents unique opportunities
to study natural processes of ecosystem renewal, such as must have occurred
following the last glaciation. Respondents to our research have expressed
interest in the uniqueness of the geological landscape as it has been exposed
through mineral extraction. The open pits of Tigroney and Cronebane present
an invaluable opportunity to view volcanogenic facies and mineralogy. One
geological respondent equated the exposed rock
formation as being “like the nude to the artist”. (see photo 2 page
33)
Beyond these considerations, uncritical acceptance of mined landscapes as
being inherently ‘problematic’ potentially has some negative economic
consequences. Respondents within the mining section of GSI expressed their
concerns that there is a prejudicial view of mining that generates difficulties
for the development of future mineral prospects. Mining very often ‘gets
a bad press’, whether deserved or not. There appears to be a consensus
amongst our respondents that the
exposed geology in the Avoca pits should be the subject of educational interpretation.
Such educational interpretation might also serve to break down some of the
stereotypes concerning the ‘damage’ (rather than value) associated
with mining operations.
2.5 Catchment Characteristics – Fisheries
Context
In general terms, the Avoca catchment is an exceptionally clean river system
with several unmanaged fisheries along its length. Three trout production
farms are located on its tributaries. The EPA through the national rivers
monitoring programme has classified the Aughrim, Avonbeg, Avonmore, Ow rivers
and the Derry water as being unpolluted (1998-2000 report). These rivers have
Q values ranging from 4-5 which indicates good water quality and high invertebrate
community diversity. The catchment is predominantly upland. In the upper reaches
the catchment consists of the Wicklow mountains to the east, north and north
west. Forestry, agriculture, tourism, industry, horticulture and aquaculture
are the main land uses in the catchment. For 230 years mining was a very productive
activity in the catchment. Currently almost 11.5 kms of river has been very
seriously polluted principally caused by leachate from the old copper mines,
resulting in a Q value of 1 (which indicates very poor water quality). The
average volume of acid mine drainage coming from this site is 35 litres per
second, depending on weather conditions. The impact of the Avoca Mines on
these pristine waters is detrimental to the biota and visually disturbing.
The clear waters turn a sterile yellow brown which covers the bed of the river,
inhibiting the growth of algae and limiting primary productivity. The toxic
impact on aquatic invertebrates and fish lead to severely diminished
populations. However as recent electrofishing surveys have shown there is
some fish life present in the polluted stretches (eel, lamprey and minnow
– Section 7), although salmonids are virtually absent in the badly affected
areas. Prior to 1850, records indicate that the Avoca was an excellent salmon
river. Dr. A. J. Went, a noted fisheries biologist in ‘A Lost Irish Salmon
River’ (1979), wrote that in 1800 the Avoca was deemed as remarkable
for the great quantities of salmon which it produced. By the 1850’s fish
were destroyed for 8 miles due to the mines being worked to a considerable
extent. In 1924, there were records of salmon getting upstream during floods
– specimens of salmon parr and smolts were recorded from the upper reaches
of the Avoca and Aughrim rivers.
Today, on the Avonmore River small brown trout (circa 20 cm) are the most
prominent feature of catches (O’Reilly, 2002). Larger trout are also
taken; some of these may be sea trout. He describes the Avonmore as a “lovely
wide river” with good instream diversity which presents many angling
opportunities. The angling water extends from Clara Bridge to Whites Bridge.
Angling on the Avonbeg is for small trout in “beautiful countryside”.
Access to the river is very difficult due to heavy bank cover in some areas.
The Aughrim and its tributaries the Derry Water and the Ow also provide trout
angling. The average size of trout in the Aughrim is greater than for the
Avonmore and Avonbeg with trout ranging from 220 to 340 g. Larger trout are
taken from time to time. Sea trout are taken during the summer and this fishery
is well regarded locally. Escapee rainbow trout can
feature in anglers catches in the Aughrim also. The Derry Water is a good
trout fishery which is not heavily fished. Trout to 400 g are taken and good
angling stocks are present. The underlying bedrock of the Ow River is granite
and is well populated with small trout. Heavy bank cover is problematical
for anglers. The Avoca main channel is occasionally angled by some local anglers
for rainbow trout, sea trout and salmon. It is not uncommon for anglers to
observe dead fish in the channel. The Avoca has some excellent angling water
ranging from shallow runs, glides to deep holding pools allied to the often
spectacular landscape of the river corridor and surrounding area.
2.6 Miscellaneous other economic and location
considerations
The mine sites should be considered in the broader context of historical and
more recent actions relating to the local economy. We note the proximity of
the port of Arklow, its expansion, and concomitant concerns over sewage, and
other pollution. Discharge from the former Irish Fertiliser Industries (IFI)
factory, located near Arklow, has had a significant impact on water quality
in the lower Avoca River. We also consider other important tourism initiatives,
and important
tourist foci and designated country walks. (Much of the following information
has been provided by Power 1998, Merrigan and Moore, various urls).
2.6.1 Arklow and oysters
An inquiry into the oyster fishing in the region in 1846 was advised that
the Arklow oyster beds were ‘inexhaustible’. The area was judged
to have the chief oyster breeding beds in Britain and Ireland. From the time
of the famine, up until the 1860’s, oysters were shipped from Arklow
in huge numbers. Over a three month period in 1850 (March to May) 24,000 barrels
of oysters were sold to French, English and Irish merchants. By this time
the oysters, although abundant, were being poisoned by the mine workings.
From ‘Oyster Fisheries: Ireland’ (1864) we find that the oysters
required “four months transplanting to purge them of their copper flavour”.
In 1863, the total catch from the region was 58,000 barrels. Many of these
were rebedded before sale on the Welsh coast and off North Co. Dublin to remove
the metallic taste. Various sources describe the once thriving oysterculture
carried out at the mouth of the Avoca, and the impact of mining on these fisheries
concerns. We note Power (op cit.) and various websites of minutes of Dáil
and Seanad Éireann:
“There are oyster-beds on the coast … the produce requires to be
freed from a peculiar flavour by the [cleaner?] waters of the Welsh and English
coast before it is fit for [food?]. The produce of the copper and lead mines
of the Vale of Avoca is shipped from the port. There are cordite and
explosives works, established by Messrs Kynoch of Birmingham, England. In
1882 an act was passed providing for the improvement of the orethe ore harbour
and for the appointment of harbour commissioners” (oyster 1 url). Seanad
Éireann - Volume 2 - 06 February, 1924:
“... The Arklow oysters were particularly good, and the French scraped
up
these beds and paid what were ... There is no doubt that we could establish
oyster beds ...” (oyster 2 url. file currently unavailable).
Dáil Éireann - Volume 197 - 07 November, 1962:
“Fisheries... Why can we not establish oyster beds....? Mr. Dillon: We
are
about to spend £6 million on the nitrogenous fertiliser factory at Arklow…”
(oyster 3 url. file currently unavailable).
Consideration should be given to the potential for oyster fisheries following
treatment of acid mine drainage from the Avoca River.
2.6.2 The former IFI factory
Irish Fertilisers Industries factory is no longer in operation, and we believe
it is currently scheduled for demolition. Until recently IFI discharged trade
effluent (rich in nitrogenous compounds including free ammonia) directly into
the Avoca River, under licence from the Environmental Protection Agency. The
impacts of this discharge are not documented (so far as we have been able
to ascertain) but are locally considered to have been significant.
2.6.3 Tourist attractions
Coy (1998) has noted that: “…at present almost 40% of all Irish
coach tours pass through or close to Avoca. Dubliners make more than three
and a half million day trips to County Wicklow each
year and many of these currently drive through the mine site, which is bisected
by the main road, without being aware of it. With the Meeting of the Waters
at one end and Ballykissangle [sic] at the other, the valley is already a
tourism promoter’s dream”. Avoca Handweavers
The mill, established in 1723, is Ireland’s oldest surviving business,
famous for woven articles of clothing and accessories. Produce is sold to
visitors and there is a café.
The Meeting of the Waters
Made famous by the poem by Thomas Moore the confluence of the rivers Avonmore
and Avonbeg is a world famous visitor attraction. A capacious and friendly
public house and restaurant is located here. Limited visitor accommodation
will also soon be provided.
Ballykissangel
The chapel in the TV programme Ballykissangel was built by Avoca miners in
1862. The show brought tourists and helped to sustain local gift shops and
Fitzgerald’s public House in Avoca village. It is three years since the
TV series ended and memories and tourists are waning. (see photo 3 page 34)
Moteee Stone
In the Vale, on the way to Rathdrum, sits a massive boulder of native Wicklow
granite deposited as a glacial erratic during the last ice age. On a clear
day you can see Wales from the top. This large erratic granite stone in a
prominent location from which the mine sites can be viewed. In legend it was
cast there by the giant Fionn MacCumhaill.
Avondale
Avondale Forest Park, 528 acres, contains one of Europe’s most diverse
collections of deciduous trees. Power notes the forest of Avondale; “the
Botanical Jewel reigning supreme…”. The demesne was laid out in
1777, and the Georgian mansion. Avondale House, birthplace of Charles Stewart
Parnell. Part of the house is a museum dedicated to him. The Irish National
Foresters movement developed the estates after 1906 as a training college
and research station.
Golf
Although prone to flooding, Woodenbridge Golf Course is “Ireland’s
most picturesque” and second oldest. Moore (1998) notes that Woodenbridge,
is one of the most beautiful 18 hole golf courses in Europe, and the proximity
of other courses:
Arklow Links, European Club at Brittas Bay is one of the great natural links
of the world, and Druids Glen venue for the Irish Open. (Moore 1998, for the
Vale of Avoca Tourism Committee).
Country Walks
A number of designated walks the ‘Red Walk’, the ‘White Walk’
and the walk to the Mottee Stone bring visitors through the Avoca mines areas.
VADA is instrumental in promoting these and is responsible for their signposting.
Avoca Tourist Information Office provides information on guided walks in the
area.
2.7 Catchment management planning
/ Water Framework Directive
The forthcoming need, under the EU Water Framework Directive, to plan for
and manage natural waters on the basis of catchment management plans must
be taken into account when developing plans for the restoration of the Avoca
River. This Directive, adopted by the Irish Government in 2000, requires that
all waters achieve ‘good ecological status’. Based on the existing
monitoring criteria, and relevant quality elements, the Avoca River is seriously
in breach of this Directive.
River Basin District plans are being developed by the Department of the Environment
and Local Government to facilitate the implementation of the Water Framework
Directive. It is anticipated at the time of writing, The Eastern River Basin
District plan which includes the Avoca catchment will be
launched shortly. For a number of years the Eastern Regional Fisheries Board
has been developing a catchment management plan for the Avoca with stakeholders.
It is intended that this will be an integral part of the overall River Basin
District plan for the Eastern Region.
Map 1 Avoca Catchment, County Wicklow, Ireland. (Courtesy
of ERFB)
14
Map 2 Avoca mine area & surrounding district, Ireland. (Courtesy of GSI)
15
Map 3 Geology of the Avoca District (Courtesy of GSI)
16
Map 4 Groundwater level contour map of the Avoca District (Courtesy of GSI)
3. Stakeholder analyses and the case for
action
Most problems have owners. Ownership confers obligations, and the rights of
individual people or groups reciprocate with obligations. This section addresses
the questions of problem ownership, public participation and stakeholder engagement:
why, who and what. We need to examine means of inclusion in this ‘ownership
problematic’ by which an individual, acting as a citizen, can be identified
as a potential partner. We identify the purpose of stakeholder analysis, responsibilities,
stakeholder typologies, stakeholder identification and stakeholder inputs
and expectations. It is also vital that any technical intervention with respect
to mine water is not considered in isolation from other problems and initiatives
about the site and about the river catchment.
3.1 Ways of Understanding
We are concerned here with how different forms of knowledge should come together
to inform our project development. We need to consider how the gap between
scientific and traditional knowledge can be bridged. Scientific understanding
is largely abstract: separate from knowledge possessed by people outside its
discourse. Local people have lived with the specific problem for a long time,
and will have to live with the consequences of proposed projects for a long
time. They
are the primary stakeholder: people most significantly impacted by the project.
Groups or organisations which have statutory obligations are secondary stakeholders
and both of these need to come together to agree technical process. The physical
characteristics of the Avoca mine sites have been widely documented, particularly
as a result of recent interest in remediation. This has largely been provisioned
through studies by secondary stakeholders, particularly representatives of
GSI and Irish Universities. As well as historical texts about the area our
attention has also been drawn
to historical letters from landowners to the Government dating from 1901,
(supplied by Ned Bayley). These indicate that the scale of this environmental
disaster is large as is the length of time it has been allowed to continue
- over 200 years. Much time, energy and resources have been spent in the past
particularly by local communities in Avoca to alleviate this situation. In
the 1900’s, Colonel Charles Bayley, a landowner in the catchment spent
more than thirty years convincing
the Government that suitable treatment was a necessity to restore this river
and it was a project that was feasible.
(Appendix III).
These letters have proven important in highlighting some issues and potential
problems concerning the future management of proposed projects, and have been
discussed by primary stakeholders.
3.2 Stakeholder Analysis. What and
Why?
Stakeholder analysis is the first step in building the relationships of understanding
needed for the success of any participatory project or policy. It concerns
people upon whom a proposed project has an impact. It assesses their interests,
and the ways these interests affect the viability of the project. It provides
the social context and background to the project – the reason for doing
it. It defines the projects purpose. It helps to identify appropriate forms
of participation. It provides
the starting point, by establishing which groups to work with, and sets out
approaches so that the aims of a project can be achieved. This analysis informs
the parameters of the design of the project by identifying roles and goals
of different groups, and is intended to formulate the appropriate means of
engagement of these groups. It combines institutional appraisal and social
concerns in a single framework.
3.3 Who are the Stakeholders?
Stakeholders are people or groups or institutions with interests in a policy,
programme or project. Stakeholders commonly claim to represent a broad constituency
(sometimes broader than is actually the case).
• Primary stakeholders are immediate communities of interest: those people
and groups ultimately affected by the problem or the project. This includes
intended beneficiaries or people negatively affected – winners or losers,
and those involved or excluded from the decision making process.
• Secondary stakeholders are the intermediaries in the project delivery
process, and include government agencies and other institutional bodies. These
may not perceive themselves as stakeholders – they simply own the process.
They may aid or deliver the process. These may include informal groups of
people prepared to act as intermediaries. They can be broadly broken into
funding, implementing, monitoring or advocacy organisations – otherwise
governmental, NGO and private sector organisations.
• Key stakeholders are those who can significantly influence, or are
important to the success of the project. Their support or lack of support
will significantly influence the success or failure of the project.
• Specific stakeholders are key individuals, such as heads of agencies,
who have both personal interests at stake and formal institutional objectives.
• Unwitting Stakeholders are people who should be concerned, but are
as yet not fully aware of the scope of the issues. Groups and individuals
can be more than one or sometimes all of these types of stakeholders. Most
of these may be composed of people who have already recognised the critical
nature of specific issues, and are addressing them, or can help to do so.
(ODA 1995; World Bank 1995; Glick, Hatcher and Ashton 2002).
3.4 Stakeholders Identified
Stakeholder analysis is aimed at enhancing stakeholder involvement in the
participatory process, prior to their actual involvement in decision making
activities. The commissioning agent (ERFB) has supplied the University of
Newcastle with a list of people who they understood would wish or should have
an input into this programme. This has been augmented during the progress
of the study as our appreciation of the area and the problem grew.
3.4.1 Primary Stakeholders
These have been identified for us as local residents, particularly people
active in local heritage initiatives and mining heritage activities, and especially
members of the Vale of Avoca Development Association (VADA), anglers on the
catchment, and people with businesses which are directly impacted by the environment.
Some commercial fishing interests are current stakeholders: IDAS Fisheries
and Annamoe Trout Fisheries, some commercial fishing interests are not currently
stakeholders but may become stakeholders in the future, Wexford district netsmen
for example.
3.4.2 Secondary Stakeholders (Key Stakeholders)
Organisations with statutory obligations associated with the problem have
been identified. These are the site owners or potential site owners and organisations
currently contributing to pollution at or near Avoca, and primarily comprise
various representative bodies within local and central government. They also
include groups by whose action (inaction) significant progress can be made
to develop an intervention at the site (or otherwise), and to progress potential
through
such intervention. These are the local authority – Wicklow County Council
(WCC), particularly environmental and economic development and tourist sections,
and various branches of the Department of Communications, Marine and Natural
Resources (DCMNR), [Roinn Cumarsáide, Mara agus Acmhainni Nádurtha]
like Exploration and Mining Division (EMD) and the Geological Survey of Ireland
(GSI). Other stakeholders include agencies under the aegis of this Department
such as The Central Fisheries Board, (CFB), [An Príomh Bhord Iascaigh]
and the Eastern Regional Fisheries Board (ERFB), [An Bord Iascaigh Reigiunach
an Oirthir]. The Environmental Protection Agency (EPA), [An Ghníomhaireacht
um Chaomhnú Comhshaoil], is a government agency with some responsibilities.
Stakeholders including Dúchas, the Heritage Service, [An tSeirbhís
Oidhreachta], East Coast and Midlands Tourism, and The Mining Heritage Trust
for Ireland (MHTI), [Iontaobh Oidhreacht na Mianadóireachta] and, The
Irish Farmers Association are
included here. By degrees of personal involvement and enthusiasm many of these
stakeholder definitions overlap. Various coalitions of secondary stakeholders,
such as county development boards, have not been canvassed at this stage.
It will be necessary to key with some of these at the next phase of development
of this work. We include a summary of the functions of these organisations
as far as they concern the outline of this survey, alongside some of our observations
of their role, or potential role, in an advance programme, as identified through
elite interviews and personal conversations.
3.5 Stakeholders who responded to this
study
3.5.1 Local Residents
Some local residents have been met with. The enquiry has always been met with
enthusiasm and kindness. We are particularly grateful to those residents who
turn up to meet us time and again on our visits to the site – often taking
time from work to do so. We have met with Avoca and Glendalough miners, and
are grateful for their personal insights to conditions at work, and personal
understanding of local geology, which, in turn, helps us and informs our process
and
understanding. Many individual respondents overlap with the following groups,
and are considered under these headings.
3.5.2 VADA
The Vale of Avoca Development Association was formed to cater for the future
development and prosperity of the area through an area action plan. The association
succeeded in getting a village renewal scheme for Avoca, including the creation
of a village park. The Old Court house has been developed into a heritage
centre and a focal point in the village. It provides permanent offices for
the local library and tourist office. The history committee of the association
have carried out studies of Avoca mining heritage leading to long term preservation.
A miners’ park and a nature and sculpture parks are also proposed (Merrigan
1998: Moore 1998; VADA urls). VADA notes the fame brought by Ballykissangel,
and is in a ideal position to build on the benefits that can flow from
developing this theme. They note the important miners’ chapel of Saints
Mary and Patrick, built in 1862, which featured in the TV series. VADA is
actively engaged in maintaining and preserving the East Avoca mine site, and
has succeeded in raising funds for the preservation of one of the engine houses
that was in immediate danger. It has a track record for environmental and
heritage engagement. (see photo 4 page 34) We are all encouraged by the enthusiasm
for the development of a programme of mine water remediation expressed by
VADA and other residents. It is important to stress, however, that the residents
are wholly opposed to any notion that the heaps or mine sites should be defiled
in any way. If we take the earlier arguments about aesthetics on board then
the
people who would stand to be most aggravated by ugly prospects are the people
who have to look at them every day. This is clearly not the case here. Local
attitudes define the mine sites and heaps in many ways: never ugly! All residents
met with, and represented through VADA, are adamant that the heaps add a specific
beauty to the place, as well as being an integral part of the vast important
heritage of the locale. When we are preparing root definitions it is important
to note
the strength of local feeling in favour of the mine sites. This in no way
detracts from the programme of work in hand. No one interviewed would be prepared
to sacrifice the water quality for the landscape. But there is no need to
do this! Intervention for water quality must give full consideration to the
important mine sites, including the open pits and colourful heaps.
3.5.3 Anglers
We have met individually with anglers and representatives of anglers, and
groups representing angling clubs. These are people who spend much of their
leisure time in and around the river, and as such constitute the ‘eyes
and ears (and nose) of the catchment’. They are able to report to the
ERFB when specific problems arise, such as fish kills through pollution spills;
or agricultural contamination incidents mentioned below (WCC). They have an
everyday understanding of the
river and its problems. Specifics of septic tank runoffs, for example, are
noted at Clara Vale, below the bridge by anglers. A focus group was held with
significant representation of three angling clubs, the Rathdrum, Aughrim and
Wicklow Anglers’ Associations. These people in turn represent over five
hundred members, a significant constituency. These respondents were wholly
in agreement with any proposal to clean the river. Some of the angling groups
currently form a volunteer riparian stewardship group, looking after all of
the problems with the water that they are able. This includes
removing storm detritus – day or night. Respondents can do little about
the water chemistry. They would be prepared to act if there was something
they could do. Many of the anglers would be willing to work with the maintenance
of a filter system, so long as they were able to continue to reap the benefits
in their sport. Concerns were raised by representatives of these groups about
commercial interests and power relationships in the long term.
3.5.4 Hospitality Businesses
Hoteliers and publicans based in the catchment have expressed a general enthusiasm
for any intervention that improves the quality of the environment. Some of
these are active on various development and tourist boards, and as such constitute
key stakeholders. They have, and will contribute freely of their understanding
of issues in the development of the project. One hotel hosts an annual dinner
for the remaining mining fraternity, and this occasion could provide a focal
point firsthand for engagement with heritage.
3.5.5 Aquaculture
One respondent for the Aughrim River fish farmers observed that those in the
aquaculture business are being asked to pay significant sums of money to filter
their effluent. They have to fit drum filters at considerable expense, yet
as things are they are filtering water to put back into a river that is perceived
as dead. The businesses are at a loss as to why they should clean water to
put into what they perceive to be a poisoned river. However it is evident
that cleaning the river will have important favourable consequences for local
employment. With the river cleaned brand names such as ‘Wicklow Trout’
or ‘Smoked Wicklow Trout’ will be products of international proportions,
with significant employment opportunities. The image would sell a product,
and the product would be both Trans Atlantic and All Irish. Further up the
catchment a fisheries owner has watched flows for many years. Fishing people
are close to the river, quite literally, and watch and note its changes. He
notes other concerns here relating to E.coli from sewage in the upper catchment;
and that children’s bathing was stopped here because of pollution fears.
The stakeholders we met who have commercial interests are wholly in agreement
with any intervention that will improve water quality.
3.5.6 Wicklow County Council
3.5.6.1 Local Authority stated commitment
We note Wicklow County Council’s stated key interests in the mine water
and the site, in terms of options and objectives, as applicable to the Avoca-Avonmore
Catchment, as stated in WCC Catchment Conversion Plan:1998 – 2008 (at
Wicklow url):
Water Quality Objectives
Strategy: Enhance water quality in the Lower Catchment and maintain good water
quality in the Upper Catchment.
Objectives:
• Improve wastewater treatment facilities within the Catchment both commercial,
industrial and municipal [sic]
• Reduce the discharges of Acid Mine Drainage (AMD) into the river
• Treat AMD entering the river
• Implement a groundwater protection plan
Avoca Mines Conversion Objectives
Strategy: To develop an integrated plan for the mine site which would address
its conservation and redevelopment as a major themed heritage tourism centre
while addressing and mitigating adverse environmental damage in partnership
with all stakeholders.
Objectives:
• Implement a leachate/AMD treatment programme with a view to treating
the Acid Mine Drainage contribution before 2007
• Reduce the visual impact of spoil heaps for sensitive receivers.
Targets:
• Instigate comprehensive feasibility study of AMD treatment and complete
within two years.
• Investigate fishing and spin-off tourism benefits of treatment of AMD
within two years.
• Conduct further site investigations to understand the contributors
to AMD.
• Investigate fund options for treatment of AMD.
• Contextually sensitive revegetation of spoil heaps to be implemented
selectively.
Tourism and Recreational Development Objectives
Objectives [selected for relevance]:
• Development of the Avoca Mine site as a mining interpretative location
in accord with a development plan.
Targets [include]:
• Identify the recreational needs (water and land) in the Catchment within
one year.
• The preparation of a conservation plan for extant industrial archaeology
at the Avoca Mine sites within one year.
• Prepare and publish a fully developed and costed feasibility study
for themed mine heritage and tourism centre within two years.
• Identify funds for emergency conservation measures and mine heritage
centre within two years.
WCC has identified environmental needs and understanding of resident communities
through a Community Sector Survey which emphasised a “high level of environmental
awareness in the catchment” (Wicklow url2). “A significant 97% of
respondents expressed specific concern over water pollution […] The area
being a catchment and the graphic nature of the contamination of the lower
Avoca River with metalliferous precipitate. The Department of the Environment
survey in 1990 reported the two highest percentages of people who responded
that they were ‘extremely concerned’, in the categories of pollution
of rivers, sea and of drinking water / quality. However total expression of
concern regarding water pollution was 62%. The catchment area appears therefore
to be endowed with a very high level of concern in respect of water pollution”.
Further to this -
“In response to whether respondents had specific local environmental
concerns; 53% positively did. Those concerns specified encompassed a wide
range of issues from Nuclear pollution, agricultural pollution, chemical/pharmaceutical
pollution, sewage pollution, drinking water quality, litter, dumps, roads,
deforestation, small bird numbers, mine pollution and traffic were reported.
By far the most frequently stated was pollution arising from particular chemical
plants and less frequently pharmaceutical plants. The distinction between
the two may not be correct due to the technical nature of the stages in pharmaceutical/chemical
plant production processes and the lack of distinction recognised by the general
public.”
3.5.6.2 Projects, Proposals and Ownership
WCC was responsible for commissioning technical investigations into site regeneration,
via the EU LIFE project. Much of the aforementioned is a direct response to
this. The local authority is caught in the impossible situation of having
to deal with significant potential pollution problems, such as the disposal
of domestic and clinical waste, and being the regulator of pollution discharges.
Notable amongst the latter are the illegal dumping activities highlighted
recently in national press. Its proximity to a megacity with remoteness of
aspect makes the county a target for polluters in various
guises. We have noted primary stakeholders’ concerns with the need for
comprehensive, catchment wide, programmes related to pollution discharges.
An unfortunate set of circumstances, particularly relating to crisis management
and subsequent failure to project consequences of technical decision making,
led to the abandoned mine, Ballymurtagh open pit (with mine waters running
through it and discharging into the river) being used by WCC as a landfill
site. This finally closed at the end of December 2002. Throughout the active
life of the landfill site no consideration was given to keeping
landfill leachate and mine based groundwaters apart. At the time there was
no knowledge of the impact of the landfill on the receiving watercourse. As
a result of this, through interaction with water running through the mine,
and open access of the mine floor to abandoned deep mine workings, leachate
from the landfill is animated by, and further contaminates, mine groundwaters.
These flow to the surface at Ballymurtagh adit, and after passing under the
main road and a short passage overground, enter the river. WCC owns the land
where treatment of Ballymurtagh discharge will take place. It also owns significant
responsibilities with respect to the discharge itself. Initial conversations
with environmental section of WCC show an understanding of the issues at stake,
especially in respect to WFD, and a willingness to make the necessary resources
available to put things right.
3.5.6.3 Other water contamination concerns
in the lower catchment
Concerns of respondents to WCC’s research were also noted in relation
to pharmaceutical industries discharges. We understand through ERFB colleagues
that as far as they know there are no current issues relating to this. The
fertiliser factory finally closed in 2002, and is currently being decommissioned.
It may, however, still pose water quality concerns into the future. Respondents
have made us aware of some of the technical concerns of the Irish Fertiliser
Industries (IFI)
plant which was located not far upstream from Arklow. IFI had been State controlled,
and was critical in its time to the economy of the Nation. As such there were
few constraints to its development. Furthermore, as the river here was perceived
to be ‘dead’ pollution was of no particular concern. Damage from
the plant began to be recognized in the 1970s. In 1995 ammonia recovery was
implemented, before which elemental nitrogen was pumped into the river. The
90s intervention reduced the volume from 2 tons of total nitrogen to less
than one ton, of which ammonia represented one third of the total. The IFI
landfill site, within the curtilage of the plant, was engineered over forty
years ago primarily to accommodate the waste products from phosphoric acid.
This included gypsum, which may be mildly radioactive, and carbon from burning
heavy fuel oil. Although this landfill is well bunded with clay a ‘hundred
year flood’ could catastrophically activate these materials.
3.5.6.4 Economic Development
Within the aforementioned WCC-generated documents there is a strong commitment
to the development of the mine site itself. The Council has a commitment to
the film industry, and accommodates tours of film locations. We note a ‘Michael
Collins Trail’, a ‘Braveheart Trail’, and ‘Ballykissangel’.
The WCC film commission also has a commitment to the
development of location of films in the County. Respondent from WCC economic
development team has worked in close liaison with VADA and various tourist
initiatives and activities. Respondent would welcome any intervention to improve
the water quality, and hence angling
tourist potential. Respondent would wish to see remediation co-ordinated with
other development activities. Respondent suggested the possibility that government
could consider possibilities of local zoning for economic development, such
as tax incentives for location of small-medium enterprises in the valley and
around the site, especially as far as regeneration or tourist based industries
are concerned.
3.5.7 The Environmental Protection Agency (EPA)
“The EPA conducts on-going surveys to assess river water quality and
trends, with respect to physico-chemical water quality standards and biological
characteristics […]”
“The Groundwater monitoring programme is implemented primarily by the
EPA, local authorities and the Geological Survey of Ireland. Monitoring is
undertaken to assess general groundwater quality and in particular the quality
of groundwater used for public and private drinking water supplies” (EPA
url). EPA will own some responsibility for enforcing WFD (at some point in
the future). Regulation as far as Avoca is concerned has been identified by
EPA personnel as the current responsibility of the local authority (WCC).
Because Avoca is not active it is not currently a scheduled industry under
the aegis of EPA.
EPA representative met with pointed to the fact that the Avoca mine water
discharge represents the single worst river pollution in Ireland. The respondent
agrees wholly with the principle that the mine water should be remediated.
EPA is also interested in the development of catchment strategy plans.
3.5.8 Department of Communications, Marine
and Natural Resources (DCMNR).
We note the Department’s stated key roles and functions as they are germane
to this report:
• Supporting the sustainable management, development and contribution
of Ireland’s … inland fisheries …
• Promoting minerals and hydrocarbons exploration and development for
the optimum benefit of the Irish economy, consistent with the highest standards
of safety and environmental protection
• Supporting and facilitating the development of the marine and natural
resources sectors by promoting effective research, technology, development
and innovation Within DCMNR the Exploration and Mining Division is charged
with:
• The application of the Minerals Development Acts 1940 to 1999 to minerals
exploration and development
• The encouragement of the early identification and responsible development
by private investors of the Nation’s mineral deposits in accordance with
best international practice
• Enhancing the attractiveness of Ireland for international and national
minerals investments by active
promotional measures. Many of these functions are wholly complementary to
proposed remediation of the mine site. We have been unable to ascertain any
potential conflict of interest with these stated objectives and a proposed
remediation project. The Geological Survey of Ireland GSI is the Irish National
Earth Science Agency. It is responsible for providing geological advice and
information, and for the acquisition of data for this purpose. GSI produces
a range of products including maps, reports and databases. Members of GSI
have made significant contributions to this survey, both in terms of supplying
reports and technical data and giving time to answer questions about the site,
its problems and its potential. It is important to note that whilst opinions
(sometimes of a technical nature) have been proffered by individual members
of the Department these do not necessarily reflect the policy or views of
the Department. Our consideration was largely confined to the East Avoca site
and discharge, comprising the open pits of Tigroney and Cronebane, and the
heap known as ‘Mount Platt’. There was a general consensus amongst
experts within the Department that the mine sites are unique and have considerable
educational potential. This is the most important historical mining site in
Ireland. One respondent described the exposed geology as ‘the Rockery
in the Garden’ referring to Wicklow’s status as the ‘Garden
County’. They would not like to see this landscape destroyed – particularly
the exposed geology, but, without exception, would be pleased to see actions
taken to remediate the water.
The Department has been charged with establishing land ownership around the
mine sites. Avoca Mine Ltd went into receivership in the 1980s, since which
time the title to the ownership of the mines (and the surrounding area, and
consequently the ownership of the problem of discharge of pollution into the
main river) is under examination. It would appear that this dispute is internecine
– ownership and responsibility ultimately rests with one or other government
department. National Government owns the responsibility of the East Avoca
mine site.GSI provided technical support to the EU LIFE project, and at that
time identified scope and potential for study areas in ecology, geology and
environmental engineering about the mine sites. The mine sites have become
habitats in their own right, for roosting bats and peregrine falcons. They
are a unique ecosystem. The spoil heaps are stabilising themselves and there
is no serious concern over wind borne pollution. There is no known risk to
human health from metal ingestion. Geologists here have pointed to parallels
with the Mynydd Parys mines in Wales and Wheal Jane in Cornwall. Respondents
also pointed to the initiatives abroad that generate an economy through celebration
of mineral heritage – cultural parks such as those in the Asturias and
Andalusía regions of Spain, and the Killhope Lead Mining Centre in
County Durham, England. Nearer to home the Breffny Mountains are exploiting
various facets of the natural and built environment, culture, folklore, etc.
Tourist coach itineraries visit the Breffny mountain landscape, why not Avoca?
Respondents drew attention to the formal layouts of Mount Usher Garden. The
rockery in the garden can be enhanced as an interpreted setting. A risk assessment
relating to general health and safety concerns will need to be carried out
prior to any exercise which invites the attention of the general public.
As well as publicising Ireland’s unique mineral heritage, part of the
remit of the mining division is making miningattractive to potential investors.
If the global economic climate was right there may be scope to develop mining
prospects here. A central concern was cost. Respondents wholly concurred that
something must be done and anything will cost something. Best option is to
celebrate the site, its history, and its geological uniqueness. Overall proposal
is remediation of water tied to broad collection of cultural/heritage/educational
measures.
Our attention was drawn by geologists to the wider geological uniqueness of
the catchment as represented by the mines at Glendalough and elsewhere.
3.5.9 The Central and Eastern Regional
Fisheries Boards
The Central and Regional Fisheries Boards are the State agencies responsible
for conserving, protecting, developing, managing and promoting Ireland’s
inland fisheries resources. They have the remit to ‘support sustainable
economic activity, job creation and recreational amenity. They are the statutory
agencies responsible for inland fisheries in the State and operate under the
aegis of the Department of Communications, Marine and Natural Resources. The
principal function of the Central Fisheries Board is to support, co-ordinate
and provide specialist services to the
Regional Fisheries Boards and advise the Minister on inland fisheries policy.
The ERFB is responsible for conserving, developing, managing and promoting
the inland fisheries and sea angling
resources from the east coast border with Northern Ireland to the South Wexford
coast. It commissioned this report into remediation of the Avoca River mine
waters. In 2001 The Eastern Regional Fisheries Board embarked on a catchment
management approach for the Avoca catchmentas enshrined in recent fisheries
legislation (1999 Fisheries Amendment Act). This process involved developing
a set of principles, guidelines and a methodological framework with the various
stakeholders in the Avoca catchment to assist in the sustainable development
and management of this resource. The principal purpose of the Avoca Catchment
Management group is to agree a plan between the stakeholders which will aim
to environmentally rehabilitate this river and its tributaries bringing environmental,
social and economic benefits to all. A primary objective of the group is to
restore the river to its full potential as a salmonid fishery. The Avoca catchment
management group believe this is essential in meeting the requirements of
the Water Framework Directive. A process of consultation with stakeholders
in the catchment was initiated, the main issues were identified and the
responsibilities of the various players were discussed. Parallel to this the
Central and Eastern Regional Fisheries Boards carried out a comprehensive
fish stock assessment survey and independently ERFB undertook a baseline water
sampling programme. Findings from the fish stock survey were positive with
juvenile trout widely distributed and juvenile salmon present at 74% of the
sites sampled. ERFB URL notes the strategic location of its region in relation
to its proximity to “major airports and ferryports [which] means that
quality angling is only a one hour drive away”. In view of the reduction
of the salmonid potential of the Avoca River in respect to its proximity to
Dublin and ferryports a massive resource under its charge is not realised.
3.5.10 Dúchas
Dúchas colleagues have been particularly helpful in working with us
to facilitate meetings with other stakeholders. We are also grateful for their
supplying us with historical letters about the Avoca mine water problems.
We have been shown important mine sites in the upper part of the catchment,
especially at Glendalough.(see photo 5 page 35). They have assisted at mine
site visits. In keeping with Water Framework Directive, water is above all
a heritage issue. WFD notes that “water is not a commercial product like
any other but, rather, a heritage which must be protected, defended and
treated as such” (WFD.1.1).
Dúchas has responsibility for the implementation of EU Habitats Directive.
The lamprey and fresh water pearl mussels, present in the Avoca catchment,
are protected under this directive, and are an indicator of water quality.
Dúchas personnel have a professional stake in the wildlife of the catchment,
and an interest in the roosting bats and the peregrine falcons in the East
pits. There are unique species of macro fauna present in the upper reaches
of the catchment. We have been made aware of the erosion of the important
mine sites of the upper catchment by storm water. These sites
have an international importance, but not at present are not recognised as
being of national significance. Interventions to protect these by diverting
storm water channels are piecemeal. As always meagre resources due to low
priority are perceived as the cause. In the wider scheme of things if mining
heritage were given greater consideration across the county and the catchment
then this might prove helpful in reprioritising these sites. Much of the upper
catchment is designated as a Special Area of Conservation (SAC), and although
acidic runoff is perceived as being linked to fish kills or absences of fish
there is no scope for intervention in the immediate vicinity. It was explained
to us that this is partly the result of conifer plantation in a tributary
valley above the Upper Lake,
Glendalough. Although no intervention can be considered it is possible that
the aggregate acidity of the catchment does not help this predicament. Dúchas
personnel are engaged in scoping the wider Avoca Catchment Plans, and have
been instrumental in their foundation. Essentially Dúchas colleagues
met with are strongly in favour of any intervention to ameliorate the condition
of the water, particularly Avoca mine waters, and would strongly support (as
resources permit) heritage and educational initiatives.
3.5.11 East Coast and Midlands Tourism
East Coast and Midlands Tourism has a responsibility to promote tourist access
to the county for angling, walking, equestrian, golf and other activities.
Tourist angling in the Avoca catchment is not especially important at this
moment in time – but it would welcome developments in that field. It
would be supportive of systems that cleaned the river and amplified the angling
dimension. It would be supportive of heritage interpretation and provision
some support in terms of infrastructure, information, etc. Their involvement
would key the developments of the site with initiatives such as
special walks.
3.5.12 Mining Heritage Trust of Ireland (MHTI)
Representatives of MHTI were met with at ERA MAPTEC, and as individuals within
GSI. Individual respondents who, as a result of personal mining engineering
and mining geological backgrounds, had an earlier interest in the development
of a mining heritage centre were also met with. We aggregate their appreciation
of the site and its potential, because by and large they concur. An earlier
lease to develop a commercial heritage concern on the Avoca site has lapsed.
MHTI boasts a significant membership, in Ireland and elsewhere. “The
Mining Heritage Society of Ireland was founded in 1996 to develop public awareness,
appreciation, conservation and enjoyment of all facets of mining heritage
throughout Ireland. The Society converted to a Trust in 2001”. (MHTI
url)
It has presented exhibitions at GSI Dublin offices as a focus on heritage
week 2001. It has many spectacular sites under its aegis in Ireland: Bunmahon,
Allihies, Mount Gabriel, others - the Avoca site is probably its most important
in terms of scale and visual impact. We are particularly grateful to MHTI
for images, maps, information (such as information about groundwater flows
in relation to climate) – all given freely and with conviviality. Although
it is widely understood that there has been ancient mining in the catchment,
at Avoca and other sites, it is, as with all mine sites, difficult to establish
evidence of this because the surface expression of the sites invariably are
altered by more recent extractive activities. Members have extensive knowledge
of and contacts with heritage groups elsewhere, particularly Parys Mountain
in Wales. Much needed heritage interpretation could be better effected if
there was beneficiation of water. One of the ways of doing this might be through
a ‘heritage’ based process. In earlier times copper was extracted
from the water through precipitation process described as ‘heap leaching’.
Reinstating this process could actively beneficiate the water as well as providing
the locus for education activities and research.
Respondent noted: “we know that the heaps are not toxic in the air because
of the grain size of the shale – even in drought conditions this would
not be affected. Therefore the heaps in and of themselves are not problematic”.
(Some - but not all – MHTI respondents perceived the heaps themselves
as an important asset). Respondents would like to see the site served in its
industrial setting – with serious conservation measures to preserve the
engine houses. MHTI and VADAare each aware of the work that the other is doing,
which is entirely complementary. At Allihies in West Cork stonemasons from
Cornwall have been employed in the restoration of engine houses. The expertise
is available to Avoca when needed. Silver mines at Nenagh, another important
heritage site, were awarded significant heritage funding. Another important
factor re Avoca is its proximity to Dublin. Underground workings are accessible,
and with the right package (and insurance) underground tours could be effected.
The MHTI is strongly supportive of actions that clean the river whilst respecting
the integrity of the mine sites.
3.6 Root definitions. The concerns and aspirations
of stakeholders and where they concur
Stakeholders are not merely people with an opinion – they are people,
groups and organisations that have an interest – something at stake in
a proposal or project. They may also have influence over the project. They
are therefore both people who are effected by, and people who can effect a
project.
• Residents, especially active through VADA, are active in environmental
issues and the preservation of built heritage in the area. Respondents are
keen to preserve the unique heaps as integral to any development. We have
not met with anyone with opposing views, and this attitude is not in conflict
with any other current initiative or group understanding.
• Intervention with mine water pollution so as to improve the quality
of the water in the river is welcomed by all respondents met with. In earlier
social surveys (WCC, EU LIFE) local residents have clearly prioritised water
quality concerns, especially in the lower catchment. All stakeholders engaged
with in this enquiry have expressed unreserved enthusiasm for cleaning up
the worst river pollution in Ireland.
• Respondents who participate in active environmental activities or riparian
stewardship would assist a remediation project where feasible. An intervention
that relies on active participation (volunteers or possibly stewards employed
through an economy amplified as a consequence of water improvement) can be
considered. The goodwill is there to actively man a project (subject to definition
of details). Technical planning may goahead under the assumption that issues
of maintenance will be addressed.
• Businesses would benefit significantly from water quality improvement.
This would have spin-off benefits forall.
• Most respondents agree the importance of an interpretation of the mine
sites and buildings. No one disagrees that there is a complementarity in acting
to improve water quality, create access to the site (although representatives
of DCMNR reserve judgement concerning access due to duty of care issues and
public safety liability), celebrate mining heritage, and develop a programme
of education and research.
• The important mine buildings need full conservation consideration.
Other important cultural sites relating to mining in the catchment need consideration
within this framework.
• These strategies all key with broader tourist initiatives.
• A clean Avoca River will be an asset that will lead to realising significant
economic potential.
• Any measures towards remediation must be planned and delivered with
full sensitivity to the site, its cultural, heritage, economical, geological,
wildlife, flora and tourist concerns and potential.
• The local authority has a continued commitment to improving water quality
for a very long time (effectively, for ever).
• Both Local Authority and National Government are ultimately responsible
as owners of the problems within the context of WFD.
4. Data sources and quality
4.1 List of data provided by ERFB and other
contacts
The ERFB supplied hydrochemical data, collected over the period October 2001
to September 2002, for the discharge from the Deep Adit and sites upstream
and downstream of the discharges in the Avoca River. A limited amount of data
was also available for the remainder of the catchment, providing a useful
comparison between the largely unpolluted water constituting the majority
of the catchment and the highly polluted river downstream of the mine water
discharges.
In addition, the ERFB supplied statistics on rod catches from local angling
clubs on the tributaries to the Avoca (Aughrim, Avonmore and Avonbeg rivers)
and collected further hydrochemical data for the Ballymurtagh Adit from Wicklow
County Council. This data was collected by the Council during routine monitoring
of leachate from their landfill site at
the Pond Lode Open Pit in West Avoca. The CFB & ERFB conducted an extensive
survey of fish stocks in the Avoca catchment in 2002 (Roche, 2003). This provided
data on the species present with information on the status of the fishery.
The GSI provided hydrochemical data, for both the Deep Adit and Ballymurtagh
Adit discharges as well as the Avoca River upstream and downstream of the
discharges, from monitoring periods undertaken in November-December 1993 and
August-October 1995. The data has been collated into reports by Flynn (1994)
and O’Suilleabhain (1996)
respectively which also contain valuable information on groundwater level
monitoring and sampling and flow gauging. The most intensive sampling campaign,
comprising adit flow and metal discharge rates in both the Deep Adit and Ballymurtagh
Adit discharges, was carried out by Trinity College Dublin, from May 1994
to May 1995, as documented by Gray (1995a, 1995b). In addition, various sites
on the Avoca River and surrounding tributaries, along with surface runoff,
were sampled and analysed by Trinity College in the period May-October 1994,
as reported in Gray (1994a). Flow data was also available for the Avonmore
River at Rathdrum (Gray, 1994b), which was used to estimate the flows in the
Avoca River (Section 6.1).
4.2 Creation of database
It is apparent from the list of data given in Section 4.1 that no continuous
programme of hydrochemical sampling has been undertaken on either the mine
water discharges or the Avoca River. The available data is held by various
sources and collated into individual reports but there is a lack of cohesion
between the data-sets with each representing discrete, short periods of sampling.
Therefore, a Microsoft Access Database has been created to process all available
data into a
consistent, usable format to support further work. This comprises surface
water hydrochemical data, divided into 9 sites representing the discharges
from both the Deep Adit and Ballymurtagh Adit and locations upstream and downstream
of
the discharges in the Avoca River, as well as several tributaries to the Avoca
River. Where a large enough data-set is available (i.e. for Deep Adit and
Ballymurtagh Adit discharges), charts showing the most important parameters
(i.e. pH, Fe, Zn, Cu) and their variation with time are given. The database
also shows flow duration curves for the Deep Adit, Ballymurtagh Adit and Avoca
River, essential for the calculation of design flows (Section 8.1). Finally,
several short extracts are provided detailing a description of the site, the
local geology and hydrogeology and mining history. The
database has been loaded onto a cd which accompanies this report.
4.3 Quality and usefulness of data
from disparate sources
As mentioned in Section 4.2, no continuous programme of hydrochemical sampling
has ever been undertaken in the Avoca Mines area but in order to carry out
a sufficiently robust assessment to justify investment in remediation works,
it is absolutely essential that at least one year’s worth of continuous
sampling be undertaken. The ERFB data, although representing a complete chemical
analysis data-set for the Deep Adit and Avoca River, excluded the Ballymurtagh
Adit
and there are concerns over data quality, given the unavoidable delay in analysing
the samples after initial collection. The GSI study in August-October 1995
yielded the most comprehensive hydrochemical data-set available to date for
the Avoca system, covering both the adits and the Avoca River upstream and
downstream of the discharges. The analyses are sufficiently detailed to support
calculation of total acidities. However, the sites were only sampled on 4
occasions over
this period. Similarly, the samples collected by the GSI in November-December
1993, although comprehensive, were concerned with East Avoca alone so no data
for the Ballymurtagh Adit are available for this period which, in any case,
only represented 2 sampling occasions. The intensive sampling campaign by
Trinity College Dublin did endure for an entire year but it appears that the
only metals analysed for were iron, zinc, copper and cadmium. The omission
of aluminium, manganese and lead precludes the calculation of total acidity
from these data (which is a key requirement for treatment design), not least
because aluminium is known (from GSI data) to be present at concentrations
in excess of iron in the Deep Adit waters.
Furthermore, other ions omitted from this data-set, such as calcium and sulphate,
need to be quantified accurately in order to allow calculation of possible
scaling problems (with gypsum and calcite, for instance) in treatment systems.
This can be a particular problem in limestone-based passive treatment systems
and / or in lime-based active treatment systems (Younger et al., 2002). The
data provided by Gray (1995a) are nevertheless very useful in revealing wide
variation in
discharge rates from the adits over the sampling period, some of which correlate
with variations in contaminant metal concentrations. Additional data were
discovered in the report by Gray (1994a), including sulphate concentrations
in the Deep Adit and Ballymurtagh Adit discharges from May to October 1994
and aluminium concentrations in the same discharges on several occasions.
However, there was still insufficient data to support calculation of total
acidities. More recent hydrochemical data for the Ballymurtagh Adit discharge
and Avoca River, collected by Wicklow County Council, provided only one sampling
occasion (November 2001) containing a representative hydrochemical analysis
but this does not include aluminium which (as mentioned above) has been found
to be present at high levels in other Avoca waters. However, these data confirm
the presence of elevated concentrations of ammonium in the discharge from
the
Ballymurtagh Adit, which is a pollutant cation rarely found in mine waters
(it is only significant in deep, alkaline coal mine waters in the UK, for
instance) and is thought to be derived from the landfill leachate which also
discharges through this adit. In order to quantify the impact of the mine
water discharges on the Avoca River, flow data is required for the river as
well as the discharges. There are no flow-gauging stations on the lower reaches
of the Avoca River, downstream of the mine area. Therefore, the nearest permanent
and operational gauging station to the study area, at Rathdrum on the Avonmore
River, was used to estimate flows in the Avoca River, by up-scaling (Section
6.1). This, understandably, is not as accurate as using data from an existing
flow gauging station.
5. Hydrochemistry
5.1 Principles of calculating
acidity from pH and metals concentrations
Mine water pollution results from the oxidative weathering and dissolution
of sulphide minerals, particularly pyrite, which takes place in mine voids
exposed to air and water. Metals (e.g. iron, zinc, copper), sulphate, and,
in the case of pyrite, acidity, are released into percolating waters which
contaminate the groundwater and surface waters to which they discharge.
The first step in the pyrite (FeS2) oxidation process involves the production
of ferrous iron (Fe2+), sulphate (SO42-) and hydrogen ions (H+) (Younger et
al., 2002):
FeS2(s) + 7—2
O2(aq) + H2O(aq) Fe2+
(aq) + 2SO2
4
-
(aq) + 2H+
(aq)
If the environment is sufficiently oxidising the ferrous iron will be oxidised
to the ferric form (Fe3+) in the presence ofbacteria:
Fe2+
(aq) + 1—4
O2(aq) + H+
(aq) Fe3+
(aq) + 1—2
H2O(aq)
Upon hydrolysis, the ferric iron spontaneously precipitates as ferric oxyhydroxide
(Fe(OH)3 and releases more protons
(acidity):
Fe3+
(aq) + 3H2O(aq) Fe(OH)3(s) + 3H+
(aq)
This ferric oxyhydroxide precipitates as an orange ochre that coats the stream
bed and banks and can be ecologically
devastating (Younger et al., 2002). Any ferric iron not precipitating can
also oxidise pyrite to produce ferrous iron and
further acidity according to:
FeS2(s) + 14Fe3+
(aq) + 8H2O(aq) 15Fe2+
(aq) + 2SO2
4
-
(aq) + 16H+
(aq)
The overall result of the above reactions is to produce water with a low pH
and high iron content. In addition, the acid produced by the oxidation process
is able to dissolve other metals, such as copper and aluminium, from clay
minerals which in themselves do not contribute to the formation of acid waters.
The hydrolysis and precipitation of the metal ions discussed above releases
protons, giving rise to ‘proton acidity’ (H+), since the metal ions
act as weak acids. Acidity can generally be defined as the amount of strong
base that is needed to raise the pH of the water to any defined pH (Younger
et al., 2002). The contributions of dissolved metals to total acidity are
so important in most mine waters that total acidity (mg/l as CaCO3 equivalent)
can be accurately calculated using the following expression:
50[2(Fe2+/56)+3(Fe3+/56)+2(Mn2+/55)+3(Al3+/27)+2(Zn/65)+1000(10 -ph)]
Other cations such as Cu (copper) and Cd (cadmium) can be added to the above
expression if they are present at significant concentrations, using their
atomic masses and valencies as shown. If the total acidity is not matched
by sufficient alkalinity (or will not be so matched after treatment), then
hydrolysis of the various metal ions will lead to development of a low pH,
which will slow further metal removal reactions and degrade water quality
(Younger et al., 2002).
5.2 Mine water discharges
The complete hydrochemistry data-set gathered for the Deep Adit and Ballymurtagh
Adit discharges is given in the Access database (enclosed on cd). It is apparent
from this that both adit discharges are of very poor quality, with low pH
(~3-4), high conductivity and very high metal and sulphate concentrations.
Total acidity is generally in the range 600-1000 mg/l CaCO3, with a couple
of exceptions in the data collected by the ERFB but this is believed to be
due to the delay in analysis of the samples after collection (Section 4.3).
The effect of this poor quality water is immediate on the Avoca River, despite
dilution, with a decrease in pH (from near-neutral to 5) and a significant
rise in metal and sulphate levels evident compared to the relatively uncontaminated
water upstream of the mines. (While high manganese concentrations do occur
in waters upstream of the Avoca mines, at the “Meeting of the Waters”,
this is the only metal present at more than background values, and is generally
not ecotoxic (though it contributes to total acidity). This manganese may
be sourced from disused lead-zinc mines further up the Avonbeg Catchment).
It is also evident that the
adit discharges are not the only source of polluted drainage in the vicinity
of the mines, with significant runoff from spoil heaps and baseflow to the
river adding to the poor quality of the river water. (see photo 6 page 35)
A look at the variation in hydrochemistry over time (Figures 1 and 2) reveals
that, despite the gaps in the data-set representing periods when no samples
were collected, an apparent improvement in water quality has occurred. This
relates to the “first flush”, representing the products of past
pyrite oxidation incorporated into solution when the mine workings begin to
flood (Younger et al., 2002). With time, and the passing of the first flush,
water quality gradually
improves. Iron concentrations, in particular, in the Deep Adit discharge have
reduced from approximately 120 mg/l in 1993 / 1994 to less than 20 mg/l in
2002. Zinc and copper concentrations have also decreased in both discharges,
although to a lesser extent. There has been little change in the pH of the
Deep Adit discharge but a slight increase has been observed in the Ballymurtagh
Adit discharge from 3.5 to greater than 4.
Figure 1 Variation in hydrochemistry of Deep Adit discharge (1993 to 2002)
Figure 2 Variation in hydrochemistry of Ballymurtagh Adit discharge (1993
to 2002)
Photo 1
Photo 1 (above) Mine water discharge from the deep adit outfall at the point at which it joins the Avoca River
Photo 2 (above) Exposed Geology of East Avoca Mine
Photo 3 (above) Plaque in the courtyard of Avoca Chapel
Photo 4 (above) Restored chimney at East Avoca
Photo 5 (above) Abandoned mine buildings, Glendalough
Photo 6 (above) Acid Mine Drainage lagoon at White’s Bridge, Avoca
Photo 7 (above) Water flowing through the Tigroney pit
Photo 8 (above) Sampling at point where water emerges into Tigroney Pit
5.3 Surface water sampling sites
As stated in Section 4.2, the hydrochemical data contained in the database
consisted of data from 9 sites, covering the range of data collected from
the various sources. The sites are as follows:
Lion’s Bridge: Upstream of the mine water discharges, on the Avonmore
River before it joins the Avonbeg River to create the Avoca River.
White’s Bridge: On the Avoca River, a short distance upstream from the
Deep Adit discharge.
Deep Adit: The main discharge from the East Avoca mine workings.
Ballymurtagh Adit: The main discharge from the West Avoca mine workings.
Coalyard: On the Avoca River, 300 metres downstream from the Ballymurtagh
discharge.
Avoca Bridge: On the Avoca River, further downstream from the discharges.
Vale View Stream: Tributary to the north of the West Avoca mine site.
Red Road Stream: Tributary to the south of the West Avoca mine site.
Sulphur Brook: Tributary on the east side of the Avoca River.
6.1 Avoca River
As explained in Section 4.3, flow data was not available for the Avoca River so a synthetic flow data-set was created using measured data from a gauging station at Rathdrum on the Avonmore River. This was carried out by calculating the mean flow rate per km2 at Avonmore and recalculating the flows using the catchment area feeding the Avoca River close to the mine area. The following equation was thus used to estimate flows in the Avoca:
QAvoca = QRathdrum × 362 233 where 233 and 362 are the catchment areas feeding the 2 sampling sites, Rathdrum and Avoca, respectively, as given in
Gray (1994b) and calculated using GIS.
To compare with the only flow data that was available for the Deep Adit and Ballymurtagh Adit discharges, mean monthly flows were calculated for the Avoca River for the 12 months from May 1994 to April 1995. The estimated flows are given in Table 6.1 below.
Table 6.1 Estimated mean monthly flow in Avoca River close to mine area (May 1994 to April 1995)
Month Mean flow (m3/s)
May 1994 11.19
June 1994 4.35
July 1994 1.86
August 1994 3.42
September 1994 4.66
October 1994 7.30
November 1994 14.60
December 1994 18.49
January 1995 33.25
February 1995 25.32
March 1995 19.11
April 1995 5.44
As expected, flows are highest in the winter months with a peak flow of 33.25 m3/s in January while the lowest flow was recorded in July, with a value of 1.86 m3/s. The synthesised hydrograph is shown in Figure 3.
Figure 3 Synthesised hydrograph for Avoca River close to mine area
(May 1994 to April 1995)
In order to select design flows for a proposed treatment system, an idea of the length of time for which particular river flows are expected to be exceeded is essential. Aflow duration curve consists of the cumulative frequencies of occurrence in selected discharge classes converted into percentages of the total number of days / months. The area under the curve is a measure of the total volume of water that has flowed past the gauging station in the total time considered. Although flow duration curves from monthly mean discharges can be derived, their usefulness is much less than those constructed from daily mean flows. Therefore, using measured flow rates given in Gray (1994b) for the Avonmore River at Rathdrum, estimated daily mean flows were calculated for the Avoca River close to the mine area for the period 1990 to 1993. The resultant flow duration curve for the Avoca River is shown below in Figure 4.
Figure 4 Flow duration curve for Avoca River close to mine area derived from synthesised
hydrograph using daily mean flows (1990 - 1993)
6.2 Deep Adit
Monthly mean flow rates for the Deep Adit discharge were gained from Gray (1995a), covering a 12 month period from May 1994 to April 1995. A seasonal pattern is evident from Table 6.2 and the hydrograph shown in Figure 5, with flows at their highest in the spring then declining through summer to reach lowest flows in the autumn. A peak flow of 37.3 l/s was observed in February while the lowest flow of 8.5 l/s was recorded in October. A comparison between Figures 2 and
3 shows that peak flows in the Deep Adit occur slightly later than in the Avoca River and persist for longer, due to the effects of recharge and the time taken for the groundwater flow to emerge at the discharge. Similarly, there is a lag time between the lowest flows estimated for the river and those measured in the Deep Adit discharge, with a more gradual decrease in flow shown by the discharge.
Table 6.2 Mean monthly flow in Deep Adit discharge (May 1994 to April 1995)
Month Mean flow (l/s)
May 1994 23.8
June 1994 16.8
July 1994 12.1
August 1994 10.3
September 1994 10.2
October 1994 8.5
November 1994 12.7
December 1994 18
January 1995 21.8
February 1995 37.3
March 1995 24.8
April 1995 15.8
Figure 5 Hydrograph for Deep Adit (May 1994 to April 1995)
As with the flows in the Avoca River, it is essential to know the length of time for which particular flows in the discharges are expected to be exceeded. In the case of the Deep Adit discharge, the only flow data available are monthly mean flows (Section 4.1) which are not as useful as the daily mean flows estimated for the Avoca River. However, a flow duration curve for the Deep Adit discharge was still produced and is given in Figure 6.
Figure 6 Flow duration curve for Deep Adit discharge using monthly mean flows (May 1994 to April 1995)
6.3 Ballymurtagh Adit
As with the Deep Adit discharge, monthly mean flow rates for the Ballymurtagh Adit discharge were available in Gray (1995a) for the period May 1994 to April 1995 and showed a seasonal cycle with the highest flows in spring declining through summer to reach lowest flows in the autumn. The peak flow in the Ballymurtagh Adit discharge during this period, 35.2 l/s, was recorded in February with the lowest flow of 6.1 l/s observed in October. This compares favourably with that given in Section 6.2 for the Deep Adit discharge, the only difference being a slightly slower rate of recovery in
the Ballymurtagh Adit discharge in winter due to differences in the post-mining hydrological nature of the two sites(Gray, 1995a). The mean monthly flows for the Ballymurtagh Adit discharge are given in Table 6.3 and a hydrograph is shown in Figure 7.
Table 6.3 Mean monthly flow in Ballymurtagh Adit discharge (May 1994 to April 1995)
Month Mean flow (l/s)
May 1994 23.7
June 1994 18.1
July 1994 11.7
August 1994 10.2
September 1994 9.3
October 1994 6.1
November 1994 9.8
December 1994 13.6
January 1995 19.2
February 1995 35.2
March 1995 29.4
April 1995 19.1
Figure 7 Hydrograph for Ballymurtagh Adit (May 1994 to April 1995)
As with the Deep Adit discharge, only daily mean flow data are available for the Ballymurtagh Adit discharge (Section 4.1) but the corresponding flow duration curve is given in Figure 8.
Figure 8 Flow duration curve for Ballymurtagh Adit discharge using
monthly mean flows (May 1994 to April 1995)
7. Biological effects of mine water pollution on Avoca River
Data on the effects of the mine water discharging into the Avoca River on
the freshwater ecosystem have been collected by the ERFB and the Environmental
Protection Agency (EPA). Routine monitoring of benthic invertebrate communities
in the Avoca River downstream of the mine water discharges has consistently
shown a significant impact on both diversity and productivity (Gray, 1995c).
Chironomidae, a pollutant-tolerant genus, show a relative increase as a
proportion of the total macroinvertebrate population downstream of the mine
water inputs. Overall, a clear decrease in faunal abundance and the number
of taxa present is evident, with only a slow improvement downstream which
never amounts to full recovery.
7.1 Effects of mine water pollution
on the Avoca River – Fish Kills
Wicklow County Council has identified a high level of environmental awareness
in the catchment with a significant 97% of respondents expressing specific
concern over water pollution in a community sector survey. The Eastern Regional
Fisheries Board in trying to highlight the environmental catastrophe have
been monitoring sections of the Avoca River for fish kills over the last number
of years. It has also been gathering comprehensive baseline survey data by
analysing water samples for a broad range of nutrients, metals and physico-chemical
parameters in order to
establish the cause of the fish kills. Water samples were taken throughout
the catchment on a monthly basis from October 2001 to September 2002. (A full
table of these results is available on the CD which accompanies this report).
Water Chemistry
The Avoca River catchment is mostly upland and the upper rivers of the system
are predominantly on peatland. Water analyses indicate that the three main
tributaries of the Avoca system, the Avonmore, Avonbeg and Aughrim Rivers
are relatively nutrient poor and unpolluted. This concurs with the findings
of the National Rivers Monitoring Programme (Biological Surveys of River Quality
1998-2000) carried out by the EPA. Water analyses also suggest that the Aughrim
river and some of its tributaries are more productive waters as indicated
by higher calcium levels. The nutrient analyses results also highlighted a
number of pollution sources on smaller tributaries which have since been rectified.
Besides Tigroney and Ballymurtagh, mining for metals was carried out throughout
the catchment with abandoned mine sites located at Glendalough, on the Glendasan
River, the upper Avonbeg and the Goldmine River. Relatively high concentrations
of lead & zinc were found in water samples from the Glendasan River. The
source of these metals is the abandoned lead mining works high up the Glendasan
River valley. However, results of the electro fishing survey and theb EPA’s
Biological Survey of Water Quality suggest that these elevated metal concentrations
do not have a significant deleterious effect upon the biota or by inference
the water quality.
The results of the analyses highlight the extreme acid sensitivity of certain
upland tributaries including, the Avonbeg, Avonmore, Cloghoge, Glenmacnass,
Glenealo, Glendasan and Ow Rivers. These acid sensitive areas are underlain
by slowly weathering poor, quartz bearing bedrock, mainly granite, and have
peaty or podzolic soils. Acid precipitation and scavenging of acid substances
from the atmosphere by evergreen afforestation adds to acidity. This acid
sensitivity is reflected by dips in pH values, regularly recorded during high
rainfall episodes. Large sections of the upper catchment
are included in the Department of Communications, Marine & Natural Resources
designated potentially acid sensitive areas (Bowman pers. comm.) and previous
monitoring carried out by the ERFB. Rapid trout mortality due to high acidity
and associated elevated levels of labile aluminium in the Lugduff River, has
been demonstrated by Bowman and Bracken (1993). However, trout were recorded
in this channel subsequently (Roche, pers.comm.)
Fish Kills
Fish kills occur regularly during low flow periods and thirteen fish kills
have been recorded on the Avoca River since 2000. Species killed included
adult salmon, sea trout and juvenile lamprey. Both salmon & all three
species of lamprey are listed Annex II species under the EU Habitats Directive.
Date No. & Species Location of fish kill Cause of fish kill of Fish
28-7-00 Large nos. trout, Avoca River downstream Ammonia discharge
eels, flatfish, of IFI plant from IFI plant
lampreys, salmon
13-12-00 600 trout Ballyduff Stream, downstream Discharge from Arklow UDC
50 eels of Arklow UDC water treatment plant Water treatment plant
salmon, lamprey
17-7- 02 10 Sea trout Avoca River D.stream of AMD discharge from adits in
Avoca-Aughrim Confluence Tigroney and Ballymurtagh
1-08-02 53 sea trout Avoca River Up stream and D.stream AMD discharge from
adits in
7 salmon of Avoca-Aughrim Confluence Tigroney and Ballymurtagh
7-08-02 2 sea trout Avoca River Up stream of AMD discharge from adits in
2 lamprey Avoca-Aughrim Confluence Tigroney and Ballymurtagh
27-08-02 2 lamprey Avoca River D.stream of AMD discharge from adits in
Avoca-Aughrim Confluence Tigroney and Ballymurtagh
19-09-02 5 lamprey Avoca River Up stream of AMD discharge from adits in
Avoca-Aughrim Confluence Tigroney and Ballymurtagh
26-09-02 2 lamprey Avoca River Up stream of AMD discharge from adits in
Avoca-Aughrim Confluence Tigroney and Ballymurtagh
29-09-02 6 salmon Avoca River D.stream of AMD discharge from adits in
Avoca-Aughrim Confluence Tigroney and Ballymurtagh
9-04-03 2 Salmon, one Avoca River Up stream of AMD discharge from adits in
smolt one kelt Avoca-Aughrim Confluence Tigroney and Ballymurtagh
17-04-03 17 Salmon, Throughout AMD affected stretch AMD discharge from adits
in
1 sea trout smolts of Avoca River, from abandoned coal Tigroney and Ballymurtagh
yard site to Woodenbridge Golf Course
19-04-03 9 Salmon smolts, Abandoned coal yard site to AMD discharge from adits
in
1 lamprey below Avoca village Tigroney and Ballymurtagh
25-04-03 6 Salmon & Throughout AMD affected stretch of AMD discharge from
adits in
1 sea trout smolt, Avoca River, from abandoned coal Tigroney and Ballymurtagh
yard site to Woodenbridge Golf Course
Table 7.1 Recorded fish kills on the Avoca System July 2000 – April 2003
On the 17th July 2002, ten dead sea trout were found downstream of the confluence
of the Avoca and Aughrim rivers during an electro-fishing survey of the Avoca
catchment. On the 1st of August 2002 a local angler reported large numbers
of dead sea-trout and salmon in the Avoca River throughout the Woodenbridge
Golf Course stretch of the Avoca. This stretch has been regularly monitored
since in order to assess the frequency and extent of fish kills. Since August
2002 ten
fish kills have been verified; dead fish have been recorded throughout the
stretch from White’s Bridge as far as Woodenbridge Golf Course, downstream
of the Avoca Aughrim confluence. These fish kills have included sea trout,
salmon and lamprey. (see photo 9 page 51)
On a number of occasions lamprey whose mobility was impaired were caught.
Many of the dead sea trout found were very fresh, this being indicated by
attached sea lice. Most salmon and sea trout were attempting to swim upstream
to spawning grounds, while all lampreys found were metamorphosed juveniles.
Even though migratory salmonids successfully spawn in the headwaters of the
Avoca catchment there is a potentially significant mortality risk to salmon
and sea trout smolts as they migrate downstream to the sea. This was demonstrated
in April 2003 when dead salmon
smolts were recorded during a prolonged period of low flows.
According to local people and anglers, fish kills in the lower reaches of
the Avoca system in the vicinity of Woodenbridge Golf Course have been a regular
occurrence for many years. It would appear that local people are accustomed
to this, which meant that many fish kills went unreported. A major fish-kill
occurred in the Avoca River downstream of the IFI plant in 2000 in which large
numbers of salmon, trout, lampreys, eels and many estuarine species were killed.
These data indicate that the main cause of the fish kills in the Avoca River
are the discharges of AMD from the two main adits at Tigroney and at Ballymurtagh.
Higher metal concentrations in the Avoca River downstream of White’s
Bridge occurred during medium to low flow episodes with the highest metal
concentrations in the Avoca River recorded at three sampling points.
1. Avoca village
2. Just downstream of Woodenbridge golfcourse clubhouse
3. The end of Woodenbridge golfcourse
The highest metal concentrations at these sampling points were zinc > iron
> aluminium > manganese, though aluminium and iron levels were very
similar with aluminium exceeding iron on a number of occasions. Sampling carried
out by Wicklow County Council over a number of years at White’s Bridge
and Avoca Bridge confirm the Avoca River is a “soft” water. The
toxicity of copper and zinc to fish varies with the hardness of the water.
Salmonid Water Regulations (1988) specify a limit of <0.3mg/l Zn in waters
of hardness 100mg/l CaCO3, <0.2mg/l Zn in waters of hardness 50mg/l CaCO3
and <0.03mg/l Zn in waters of hardness 10mg/l CaCO3. In relation to copper
the limits are <0.04mg/l Cu, <0.022mg/l Cu and <0.005mg/l Cu respectively.
The ERFB Avoca River metal results would indicate that the above limits for
Zn and Cu are exceeded regularly under low flow conditions. Aluminium is highly
toxic to fish in the monomeric labile form which if present may also contribute
to the fish kills, this fraction has not been monitored in analyses to date.
Direct observations on the effects of mine effluent on fish in the Avoca River
have also been carried out previously. In April 1986 (Fahy & Reynolds,
1987) rainbow trout were held in cages in the water of the Tigroney Adit (East
Avoca).
The fish died within two hours of being introduced to the channel and held
in cages. An examination of the fish, postmortem revealed considerable skin
damage. There was no damage to the dermis nor was there time for an inflammatory
response because death had been so rapid.
In 2000, The Eastern Regional Fisheries Board conducted a similar experiment,
placing brown trout in cages in the main channel approximately 0.75km downstream
of the adits. The fish died within an hour of being introduced to the channel.
Although in the main channel they would not be exposed to such heavy concentrations
of the pollutant as in the adits, death still did occur. Fahy & Reynolds
(1987) also found that even if death does not occur in every case, it appears
likely that mine effluent
predisposes fish to other skin conditions. A survey of flatfish along the
east coast of Ireland in 1982 reported the highest levels of lymphocystis
skin disease in the marine waters at the mouth of the Avoca River. These data
and the virtual absence of fish in the lower Avoca in the course of the electrofishing
survey point to a severe toxicity problem in the channel downstream of the
mine discharges. From the above information it can be said that the acid mine
drainage from the Avoca River is responsible for fish kills. The ERFB will
be undertaking a more intensive sampling regime on the AMD affected stretch
of the Avoca River in the near future. Samples will be taken on a weekly basis
and the range of parameters monitored will be widened. In order to ascertain
what parameter within AMD is the principal cause of fish mortalities. However,
the numbers of juvenile salmon as recorded in electrofishing surveys in 1988,
(O’Brien unpublished) and in 2002, (Roche, 2003) have shown that fish
can migrate through the polluted stretch of river. This is likely to occur
when the river is at higher flows. Subsequently they successfully spawn in
the upper reaches of the catchment.
7.2 Fish Stock Surveys 2001/2002
Extensive electrofishing surveys of fish stocks were carried out by the Central
and Eastern Regional Fisheries Boards in 2002. A total of 62 sites were sampled.
Juvenile salmon were widely distributed at 74% of all sites sampled throughout
the catchment, (Roche, 2003). This has demonstrated that the system is capable
of producing salmonids and cannot be classified as ‘dead’. Importantly
it demonstrates its potential to be restored as a salmonid fishery. (see map
5 and photo 10 pages 49 and 51) Although the polluted section supports little
by way of resident salmonids other species including lamprey and eel were
present. This suggests that these species may have some tolerance to this
form of toxic pollution. Three species of lamprey are found within the catchment,
(Brook, River and Sea Lamprey). (Appendix 4 provides details relating to densities
of salmonids in the Avoca Catchment) The presence of salmon fry is regarded
as an indicator that adult salmon had spawned at, or in close proximity to,
the location at which this life stage was recorded. On this basis adult salmon
penetrated up into the upper reaches of the Avonmore, the middle reaches of
the Avonbeg and the upper reaches of the Aughrim complex in Winter 2001. While
densities of fry were low this survey has established that salmon continue
to enter the Avoca to spawn despite the toxic
nature of the water through which they must ascend to reach these spawning
areas. The homing instinct of salmon to return to their natal stream is well
documented and it is reasonable to assume that these fry are the progeny of
Avoca fish – the remnants of a population which continues to survive
despite being subjected to this long standing pollution problem. The wider
distribution of salmon parr compared to fry indicates that there are no barriers
to migration and salmon could
ascend further into the headwaters than is the case at present. This further
highlights the productive potential of the system. (see map 6 page 50)
Brown trout dominate the Avoca catchment and were widely distributed in the
upper main channel and its tributaries.Good densities of 1+ and older trout
were a feature of the results at the majority of sites. Trout growth rate
is slow andthe number of fish > 20 cm length is limited. The population
is typical of a poorly buffered system with large numbers of slow-growing,
short-lived fish. Given that juvenile trout in this system are just as likely
to be migratory fish (i.e. sea trout) this augurs well for sea trout populations
in the Avoca system. (see photo 11 page 52) Fresh Water Pearl Mussels (Margaritifera
margaritifera) and otters are found throughout the Avoca catchment, these
are
also both Annex II species under the Habitats Directive and are protected
under this Directive and other national legislation.
7.3 Future work on biology of Avoca River
to facilitate future demonstration of the benefits of remediation
It is proposed that future work should be carried out on the biology of the
Avoca River to determine the effects the
remediation system is having on the freshwater ecosystem. Such work has previously
been carried out on the River
Pelenna in South Wales, following the construction of a series of passive
wetland treatment systems to treat mine water
discharges (Wiseman et al., 2002). Ecological studies included the monitoring
of invertebrate populations which were
analysed using a number of biotic indices, such as the Biological Monitoring
Working Party (BMWP) Score, Average
Score Per Taxon (ASPT) and total abundance. A multivariate classification
technique, TWINSPAN (Two-Way INdicator
SPecies ANalysis), was also employed. This statistical tool splits sites into
groups that are essentially similar in
taxonomic composition. Indicator species that show a preference for each group
are identified and the relationships
between the site groupings and environmental variables can be explored. In
addition, fish population data were gathered
for a period following mine water treatment as well as riverine bird populations,
which assesses the effects higher up in
the food chain. The results of this study reveal how the biology of the River
Pelenna has improved since the treatment
system was installed with an observed increase in total abundance and species
diversity of macroinvertebrate populations
and the quick recovery of trout populations. The total number of sightings
of riverine birds has also increased, particularly
the dipper, which is an important indicator species as it feeds exclusively
in the aquatic environment and therefore
requires clean water conditions.
The ability of the biological communities to recover on the Avoca River was
demonstrated by Sullivan (1995). Asegment
of the channel was diverted from the first major point of pollution 500 metres
downstream of White’s Bridge in order to
determine the degree of recovery of habitat/invertebrates to the polluted
stretch. She found although initially the recovery
was slow, the continuous scouring of affected areas by clean waters upstream
resulted in the gradual recovery of the river
bed. One year later where no invertebrates were found before, a diversity
of life was re-established. This encouraging
result shows that the biota in the system have the capacity to recover and
recolonise sections that have been severely
degraded.
The success of these projects suggests that similar work could be carried
out on the Avoca River following treatment of
the mine water discharges. By monitoring the recovery of invertebrate populations,
fish population and riverine bird
species, the benefits the remediation system is having on the biology of the
river will quickly become apparent.
7.4 Future Potential of the Catchment
Fisheries Potential
In comparison to many Irish catchments the headwaters and middle reaches of
the Avoca catchment are in very good
condition physically. The catchment has excellent production potential and
the presence of good trout stocks shows that
University of Newcastle University of Newcastle Restoring the A Restoring
the Avoca River voca River
45
the system can support salmonids. There is an abundance of clean well-oxygenated
gravels ideal for spawning in many
parts of the catchment allied to the availability of good quality nursery
water.
The Avoca is a softwater catchment with excellent potential as a salmon and
sea trout fishery which is not being realised
because of a major water quality problem. It offers some excellent angling
water – all of the large tributaries have an
excellent range of holding pools and angling runs particularly the Avonmore
and the Avoca.
The Avonmore River is an established fishery, containing a good stock of wild
brown trout. The Rathdrum Trout Angling
club are very active in the area and the Avonmore river is regularly fished
by local and visiting anglers.
There are some statistics available from the local angling club on fish catches.
Although information is absent on catch
per effort, the catches do indicate reasonable fish stock numbers. Fahy &
Reynolds (1985), summarized a register of wild
brown trout catches made during four angling competitions. It found that the
average size of fish caught was 5.7 to 13
inches in length, average weight was 4-5ozs and the captured fish were two
years of age.
In a submission to the ERFB from the Rathdrum Trout Angling Club (2002), the
average size of fish caught is 5 to 14
inches in length and can weigh from 3-4 ozs up to 1.5lbs. Every year some
specimen fish are caught and in March 2002,
two fish over 7lbs were caught in the upper region of the river, (these were
more than likely migratory fish). Catches from
angling club competitions on the Rathdrum River are as follows:
Date No. Fish caught Overall weight Ranging from:
29 May 2000 25 8-9 lb 5-8 oz
12 July 2001 13 4.5 lb 4-6 oz
16 August 2001 5 2 lb 5-6 oz
20 September 2001 14 3.5 lb 4.5-9.5 oz
16 March 2002 15 4.5 lb 4-6.5 oz
12 April 2002 10 3 lb 4.5-5 oz
14 June 2002 6 1.5 lb 3.5-5 oz
12 August 2002 12 4 lb 4.5-5 oz
Table 7.2 Returns from angling competitions on Avonmore River 2000 - 2002
(Courtesy of Rathdrum Trout Angling Club)
These catch results are consistent with Fahy & Reynolds findings in 1985.
Angling Tourism
The restoration of the river would bring enormous benefits to the local community
and to the State. This river has the potential to be developed as a premier
salmon and sea trout fishery on the East Coast. It is estimated that the potential
value of the recreational salmon and sea trout angling resource on the Avoca
system of this fishery if fully realised could generate up to €750,000
per annum. This figure is derived from the following information:
• 3,077 salmon and sea trout licences were purchased in the Eastern Regional
Fisheries Board in 2001 (Central Fisheries Board, 2001)
• Of this it is estimated that 28% of these licences were sold to overseas
anglers and 72% to domestic anglers, (CFB estimates)
• It is estimated by ERFB, that of the 3,077 licences sold in 2001, at
least one third of these would fish the Avoca for salmon and one third for
sea trout. This figure would seem to be reasonable taking into account estimates
for catchments of a similar size and the aesthetic beauty of the Avoca valley.
• Bord Fáilte estimate the average expenditure by overseas salmon
anglers is €406.60. This includes expenditure on accommodation, food,
beverages, tackle, bait, boat hire, ghillies, permits/licences, gifts, souvenirs
etc. (Bord Failte, 2000 & Indecon, 2003). It must be borne in mind that
this is a conservative figure as Indecon in their own research estimate that
this figure is in excess of at least €600 per overseas salmon angler
and could reach up to €2,000 in some instances. For the purposes of this
exercise, the more conservative figure of €406.60 is used.
• It has been estimated by Indecon (2003) that the average daily expenditure
by domestic salmon anglers is €136.50 and that the number of days per
trip is 2.5.
• It is estimated by the ERFB, that the potential run of salmon in the
Avoca catchment would be 500 per annum and 2,000 sea trout. Using this data,
it is estimated by ERFB that the potential additional income from an established
salmon fishery would be €500,000 and for sea trout €250,000 per
annum. Salmon and sea trout fishing are niche markets and with declining sea
trout opportunities in the West of Ireland demand now exceeds supply. These
estimates do not take into account the
existing brown trout fishery in the catchment which also has the potential
to generate additional income. The development of angling would encourage
visitors to stay in the Wicklow area for a few days. At the moment thenumber
of visitors to Wicklow is high, but the vast majority only visit the area
for a few hours, thus depriving the local area of many knock on benefits.
Revenue would be generated from anglers who would stay in the area for fishing
and income would be generated from licence fees and permits, angling guides,
accommodation providers, shops and restaurants. In summary the value of this
river once restored would be enormous to the local community bringing economic,
tourism, social and cultural benefits.
A clean water supply
The intrinsic value of an unpolluted river flowing through Arklow would be
extremely valuable especially in relation to the future development of this
town. For most of the year the majority of all drinking water for Arklow is
abstracted from the Goldmine River. It is a large town, and growing rapidly
as a commuting town to Dublin (projected to double in population by 2014).
The current abstraction source will not be adequate and Arklow UDC are looking
into the provision
of extra water supply by boreholes. Benefits in the form of potential employment
from industries requiring a source of clean water could be enormous. Arklow
is a port town with excellent road and rail links to Dublin and Rosslare.
There is potential for the development of aquaculture following the treatment
of acid mine drainage from the Avoca River. Oyster fishing is one area that
has potential given that it was very productive in the 1850’s (sect.
2.6.1). Similarly trout could be branded as ‘Wicklow trout’ or ‘smoked
Wicklow trout’ from a clean catchment.
Other improvements in the catchment
Arklow UDC are working with the ERFB to install a fish pass at their water
abstraction point on the Goldmine River. Wicklow County Council plan to upgrade
the three overloaded waste water treatment plants at Avoca, Laragh and Rathdrum
in the near future. Much of the commercial forestry in the upper reaches of
the catchment is state owned and after harvesting will revert to Duchas as
part of the Wicklow Mountains National Park. Very little of this is to be
replanted, and where replanting is to occur it will reflect the acid sensitivity
of these areas. The IFI plant, upstream of
Arklow which in the past was responsible for gross pollution of the Avoca
River came under IPC licencing in the mid 1990s and substantial improvements
in river water quality have been noted since then. The IFI plant then closed
down in late 2002.
Map 5 Electrofishing sites sampled with backpacks
& land based units in 2002
(Courtesy of CFB)
Map 6 Distribution of salmon parr in the Avoca Catchment 2002
( handset sites/ / / boat fished sites). (Courtesy of the CFB)
Photo 9 (above) Dead sea trout taken from the Avoca River at Woodenbridge
Golf Club, 2002
— Cause of death believed to be mine water toxins
(Largest dead sea trout was 47cm, smaller fish ranged from 24.8 - 30.9cm)
Photo 10 (above) Electrofishing on the Avoca River
Photo 11 (above) Sea trout from the Avoca Catchment, 2002
Photo 12 (above) View of accessible underground workings (Courtesy of M. Critchley)
8.1 Definition of design flows and design contaminant loadings
8.1.1 Acidity loading as the key design parameter
A key task in any engineering design for water / wastewater treatment is the selection of ‘design loadings’, in other words the flux of contaminants per unit time which the treatment system will be designed to accommodate. Loadings are calculated as the product of flow rates and contaminant concentrations, yielding a value with dimensions of M.T -1 for any given contaminant. For the treatment of net-acidic mine waters such as those characteristic of the Avoca site, the usual ‘contaminant’ for which loadings are calculated is total acidity. As described in Section 5.1, total acidities can be reliably calculated when complete analyses of contaminant metals are available. Unfortunately, very few of the available analyses from the site contain sufficient synchronous determinations of the key parameters to allow calculation of total acidities for the two principal mine water discharges. However, using the most reliable recent data available (see comments on data quality in Section 4.3) we obtain the following values:
Deep Adit (East Avoca): Total acidity = 623 ± 46 mg/l (as CaCO3 equivalent)
Ballymurtagh Adit: Total acidity = 710 ± 40 mg/l (as CaCO3 equivalent)
If the acidity values are combined with synchronous flow measurements then the following acidity loadings are obtained (for acidity as CaCO3 equivalent):
Deep Adit (East Avoca) (only three data-pairs available): 9.8 ± 0.3 g/s
Ballymurtagh Adit (only four data-pairs available): 5.1 ± 0.8 g/s
8.1.2 Loading / flow rate relations
The flow rates implicit in the above acidity loading rates show (from monthly spot gaugings for the 12 months from May 1994 to April 1995) the following characteristics at the two main discharges:
Deep Adit (East Avoca):
Maximum flow = 37.3 l/s
Mean flow = 17.7 l/s
Minimum flow = 8.5 l/s
Ballymurtagh Adit:
Maximum flow = 35.2 l/s
Mean flow = 17.1 l/s
Minimum flow = 6.1 l/s
If the mean flows from this data-set are combined with the mean acidities from the full suite of samples for which acidities are calculable, then the following “average” acidity loadings are calculated for the two point discharges:
Deep Adit (East Avoca): 11 g/s
Ballymurtagh Adit: 12 g/s
Comparing these values with those calculated from truly synchronous flow / acidity data pairs suggests that the value of 9.8 ± 0.3 g/s acidity loading for the Deep Adit, is reasonable for design purposes, whereas the value originally obtained for the Ballymurtagh Adit is probably an under-estimate (due to the data-pairs being skewed to low flow occasions), and a value closer to 10 g/s is probably more appropriate for Ballymurtagh Adit also.
8.1.3 Maximum flow to be treated
Beyond calculating reliable loadings, a key consideration in selecting design flows is satisfying the need to treat the minimum flow needed to substantially improve the river, whilst avoiding over-sizing the system such that it would treat more water than is necessary (which would entail excessive expenditure to no avail). In seeking to apply this logic to the Avoca system, the criterion for deciding how much of the water must be treated relies critically on the impacts of the mine water discharges on the ecology of the Avoca River. It is axiomatic amongst anglers with local knowledge (and to
a certain extent demonstrable from the data collected by Professor Gray and co-workers at Trinity College Dublin in the mid-1990s) that the mine water discharges into the Avoca River are principally problematic when the flows in the river are low.
As explained in Section 6.1, river flow data for the Avoca River downstream of the mine water discharges (and upstream of the tributary with the Aughrim) are not available, but can be estimated with reasonable accuracy by up-scaling from measured flows at the Rathdrum gauging station upstream. Based on this analysis, and the flow duration curve derived from the synthesised hydrograph for the Avoca River at Avoca Bridge, baseflow conditions in the Avoca River are at their lowest when flows are at or below the Q90 value of around 2 m3/s. At such times the combined inputs of the Ballymurtagh and Deep Adit discharges (S = 50 l/s) still amount to no more than about 2.5% of the total flow in the river. Nevertheless,
the buffering capacity of the Avoca River is so weak (reflecting its source in peaty uplands) that pH in the main channel is seen to fall as low as 4.4 at the Coalyard sampling point (and can still be as low as 5 at Avoca Bridge downstream) during low flow spells. (These values compare unfavourably with measured pH values in the river upstream of the two main discharges (at White’s Bridge), which fall in the range 6.4 to 7.0). Comparison of the hydrographs for the Avoca River and the two mine water discharges shows that river flows reach their maxima during the four months November through February. To judge from the single year of monitoring data available for the adit discharges, peak flows from the two adits generally also occur in the same four months, but a slight lag (due
no doubt to recharge and groundwater flow delays) means that relatively high adit flows can persist through April and May, by which time flows in the Avoca River are already generally low. One would expect this pattern to lead to severe disruption of egg survival in redds which might have been laid during the preceding (wetter) four months. The inference is that treatment systems for the two adits will need to entirely capture flows of the sort of magnitude seen in April and
May if they are to substantially improve the ecology of the Avoca River. In practice, this means that treatment capacities of 25 l/s will be needed for both adit discharges.
8.1.4 Summary of identified design parameters
In summary, on the basis of the data currently available, it is recommended that for each of the two major adit discharges at Avoca, the following common design parameters be adopted:
Maximum flow: 25 l/s (with any flow above this being passed to the river without full treatment)
It should be noted that the plan to treat up to a maximum of 25 l/s will still benefit the watercourse substantially during periods of high flow, for during these periods 25 l/s of both discharges will still be treated, leaving only 12 l/s and 10 l/s respectively of the Deep Adit and Ballymurtagh discharges to flow untreated to the river. Thus, at times of peak flow, contaminant loadings entering the Avoca River will be only one-third of those entering the river during high flow periods
at present. Acidity removal rate required: 10 g/s
Given the dependence of total acidity on the concentrations of key contaminant metals (see Section 5.1), implementation of the above acidity removal strategy will ensure the pro-rata removal of all metals and metalloids of concern, ensuring attainment of the goal of minimising toxic impacts on invertebrates and fish in the receiving watercourse.
8.2 Availability of land for treatment systems.
8.2.1 Sites proposed for two major treatment systems.
One of the most encouraging aspects of the Avoca mine waters problematic is the existence of approximately 1 ha of publicly-owned land immediately downstream of each of the two adit discharges. Furthermore the parcels of land in question are currently unused / under-used, and therefore seem to offer ideal locations in which to install and maintain treatment systems for the two mine waters.
Nevertheless, a number of key uncertainties exist in relation to these two sites, and these will need to be addressed prior to finalisation of detailed treatment system design. Key issues requiring clarification are:
• The precise identity of the land-owner: if the land is, as is commonly believed, publicly owned, it will be important to establish whether title rests with local or national government, and, if the latter, which government department owns the site.
• The willingness of the owner to release the land for the intended development of treatment works, and the cost (if any) which will need to be met to secure the land.
• The full extent of available land down-gradient from the highest point of water emergence at each of the two sites.
• The existing topography of the sites: i.e. accurate topographic surveys will need to be made of the available land, yielding large scale plans (at least 1:1250 scale, preferably 1:625).
• Development control issues, including the quality of the land (which will presumably also require surveying by means of trial-pitting and percussion-hole soil sampling and associated lab analysis), regulatory requirements for dealing with any contaminated land identified (bearing in mind the intended land-use) and any other planning constraints.
• Flood protection requirements, given that both parcels of land lie on the floodplain of the Avoca River.
• Site access issues, both during construction and for maintenance / reagent delivery vehicles once the treatment systems are in use. Key issues include any local authority restrictions on traffic movement etc, to ensure compatibility with safety of traffic on adjoining public highways.
Clearly, open dialogue between the project stakeholders will be needed to resolve the above issues, and this is proposed to take place within the programme of further consortium-building advocated in Section 9.1 below.
8.2.2 Tigroney Pit: site for possible pre-treatment and / or educational facility.
During the site visit on 9th December 2002, it was observed that the bulk of the water which flows from the Deep Adit (East Avoca) first comes to daylight much higher up the hill, within the abandoned open pit working known as the Tigroney Pit. (see photos 7 & 8 page 36) Water emerges from flooded old workings (which lie beneath Mount Platt, beyond which they are thought to be in continuity with the old workings exposed in the Cronebane Pit), flows across the pit floor for several tens of metres, ponds to form a small pit lake in the lowermost part of the open pit, and then decants into an old stope which has been breached by the Tigroney open pit workings. Underground observations made by Dr. Martin Critchley show that the water entering this stope cascades into the White’s Level, whence it flows for some 200m outbye, before cascading down another stope to the Deep Adit, from which it finally emerges at the familiar adit discharge point below the railway line near White’s Bridge.
Field measurements were made (and samples taken for lab analysis) during the site visit of 9-12-2002, at each of the following three points:
• Point where water emerges into the Tigroney Pit
• Point where water decants from the Tigroney pit into the top of the breached stope
• Point of upwelling in the portal of the run-in Deep Adit
Table 8.1 summarises some of the key characteristics of the waters seen at each of these points.
Table 8.1. Samples collected 9-12-2002 which illustrate the hydrochemical evolution of water flowing through the Tigroney Open Pit and subsequent underground workings leading to the portal of the East Avoca Deep Adit
While repeated sampling is advisable before drawing definitive conclusions, these preliminary data appear to suggest that significant attenuation of iron (around 60% removal) occurs as the mine water flows through the underground workings. The modest concomitant decline in sulphate suggests that much of this iron is removed from solution in the form of hydroxysulphate precipitates. A similar process probably accounts for the 40% decrease in copper concentration and the minor decreases in dissolved Zn and Al. These observations (if borne out by later sampling) have significant implications for possible uses of the Tigroney Pit for various purposes. In particular, if a first stage in treatment were installed here, it would run the risk of destroying the reaction chain which currently removes significant amounts of metals within the workings. Indeed, the introduction of pre-neutralised water to the workings could lead to dissolution of hydroxysulphates(which are stable only at low pH) and remobilisation of toxic metals. On balance, it is probably best to reserve the
Tigroney Pit as a location in which to develop educational features (geological, microbiological and chemical; see 8.3.1 below).
8.3. Additional assumptions lying behind definition of treatment options
8.3.1 Educational / research facilities to be incorporated into preferred option
In line with the stated intention of remediating the Avoca mine waters in a manner consistent with the conservation and promotion of the mining heritage of this unique area (see also Section 8.3.4 below), we believe it is essential that treatment plans incorporate the development of facilities that will allow the safe, hands-on use of parts of the site for educational purposes. Specifically, we propose to include the following facilities into the design of the treatment system which is finally adopted by the Avoca stakeholder community:
• precipitation ponds, in which the former practice of using scrap iron to reductively precipitate copper from the mine water can be reinstated as an educational activity for school students and other visitors
• facilities for the collection and re-use of ochre, particularly as a pigment for artistic purposes (“Avoca Ochre”). (For further discussion on this point see Section 8.3.3 below).
• observation and interpretational materials to allow students and other visitors to fully appreciate the geology, mining history and impressive geomicrobiology of the site (the latter manifest in the impressive bacterial colonies which have developed in the flowing mine waters within the Tigroney Pit and (seasonally at least) at the point where water emerges from the Deep Adit)
8.3.2 Participatory dimension of treatment system operation and maintenance
One of the impressions which emerged from the stakeholder analysis (Section 3) is that the lack of success of the various earlier initiatives which sought the remediation of the Avoca mine water discharges can be attributed to a lack of involvement of key stakeholders (particularly local residents) in early decision-making. Experience of analogous developments with which we have been intimately involved in Britain further suggests that long-term sustenance of an agreed remedial strategy depends on the continuing engagement of stakeholders in the operation and maintenance of the treatment system. Amongst other motivations, these considerations prompt the proposal that local residents, and officers of governmental bodies active in the district, be engaged in the daily up-keep of the treatment system. To this end, it is proposed to include in the final design for the preferred option elements which will facilitate the safe involvement of individuals and small teams of residents / other stakeholders in the ongoing operation and maintenance of the treatment system. Typical problems which are readily amenable to solution by such participatory operation and maintenance include the clearing of channels and pipes, regulation and monitoring of flows, sampling and on-site measurements of plant performance variables and the retrieval and drying of ochre.
8.3.3 Sludge management and ochre recovery for re-use
As noted by Younger et al. (2002), mine water treatment inevitably results in the production of large volumes of semisolid waste materials (sludges) which are rich in metals. Management of such sludges is a key issue in mine water treatment. Under the most favourable conditions, these sludges can be viewed as a resource, being recovered for use as pigments or chemical reagents. In the past, it has been far more common to view these sludges as a waste requiring disposal by landfilling or some other process. The most sustainable mine water treatment solution will incorporate the
recovery of as much of the sludge as possible for various re-use purposes. Ochre recovery and re-use is currently a hot topic for research in the USA and the UK, research in which our team are deeply involved (with substantial funding from the UK government).
8.3.4 Wider educational / heritage use of the surrounding mined landscape
It is essential that any remedial actions be developed in such a manner that they complement the wider use of the mined landscape for heritage / tourism / educational purposes. This is clear from the views of stakeholders summarised in Section 3.5. While it is beyond the scope of this report to specify precisely how this might be achieved, this should be given full consideration during detailed design stages of any full-scale remedial system.
8.3.5 Conceivable options not considered in detail
8.3.5.1 Hydrogeological interventions and revegetation
Part of the rationale behind the GSI investigations in the mid-1990s was the hope that interventions might be identified which would allow prevention of recharge to the mined voids and / or divert clean water before it becomes contaminated. Such a hope is frequently examined in analogous studies worldwide, and examples have been reviewed in some detail by Younger et al. (2002). In line with common experience, no obvious interventions have been identified which would be likely to yield a major improvement in the situation in the Avoca River. Even completely back-filling and capping the open pits is unlikely to be effective (as the Ballymurtagh landfill demonstrates), and would entail the destruction of many valuable mining heritage features (as discussed in Section 2.5). Revegetation of spoils was investigated in the EU LIFE project. While this may be an appropriate means of changing the site appearance under certain circumstances, as mentioned in Section 2.5.2 it is highly unlikely to result in any great change in the amount of polluted water being generated on the site. These options are therefore not considered further in the sections which follow.
8.3.5.2 Pipe line to the sea While the notion that the sea is a robust receptacle for polluted waters unfit for freshwater streams is highly dubious, the suggestion has previously been made in other contexts that piping of the polluted water to the sea may be the most sustainable option. In the only known case where this has been tried (Skinningrove, Cleveland, UK), pipeline ruptures
quickly led to the re-establishment of pollution in the stream which was to have been cleaned. Precipitation of ochre in mine water pipes is also a significant problem requiring frequent, expensive maintenance. Piping to Shelton Abbey for treatment, would likewise have maintenance implications. This option is therefore not considered in any more detail.
8.3.5.3 Use of magnesium hydroxide wastes
It has previously been suggested (Prescott and Kilkenny, 1997) that waste magnesium Hydroxide slurry from the Premier Periclase factory (where it is used to remove suspended solids and silica from seawater) could be used as a low-cost reagent for treatment of the Avoca mine water. While this at first sight appears an environmentally beneficial option, it is important to carefully review the implication of using this material on the overall operation of a mine water treatment plant before pursuing it enthusiastically. The key considerations are:
• Reagent Availability
• Haulage cost and environmental impact
• Impact on plant design
• Reagent dose
• Sludge disposal
Reagent Availability
The availability of waste magnesium hydroxide from Premier Waste is dependent on the continued operation of the process by the company and the frequency at which it is wasted from the process. This is not in the control of the Avoca plant operator and therefore sufficient buffer storage would need to be provided to ensure adequate reagent availability on site and a contingency plan put in place to cover the possibility of the Premier Periclase Ltd. suspending it’s operation.
Haulage
The MSc identifies that some 3,000 tonnes of waste magnesium hydroxide would be required to treat the flow per annum, which compares (as will be seen in Section 8.5 below) to 800 tonnes of lime. Transporting magnesium hydroxide to site would therefore require significantly more vehicles. The use of rail transport is technically feasible as the national railway passes the site. This option would however require the construction of a rail siding and reagent holding facility at the
treatment site. The capital cost associated with this could be significant.
Reagent Dose and Rate
The maximum pH that can be achieved using magnesium hydroxide is about 10, however in practice the limit is between 9 and 9.5. As the pH approaches this value significant excess reagent has be added to ensure that the target pH is achieved in within a reasonable time. Therefore to operate a mine water treatment plant at target pH of around 8.5, excess
magnesium hydroxide and a larger retention time would be required.
Impact on Plant Design
The kinetics of the magnesium hydroxide reaction is significantly slower than that of lime or sodium hydroxide. As a
result large reaction vessels would be required to allow effective mine water treatment. Typically this would require the
vessel sizes to be doubled, resulting in an increase in:
• Plant construction costs (due to the large plant size and the requirement for mixers to cope with the greater volume).
• Increased operational cost due to larger mixer size.
In addition to impact on reactor size, it is anticipated that additional costs would be incurred due to the need to build
larger reagent storage vessels.
Sludge Disposal
In comparison with conventional lime precipitation magnesium hydroxide results in a denser sludge. This dewaters to a
smaller volume thereby producing lower sludge disposal costs. However laboratory batch trials undertaken a Cardiff
University has confirmed that the use of magnesium hydroxide offers little or no advantage in terms of sludge volume in
comparison to a HDS plant. Therefore the use of magnesium hydroxide does not offer an advantage in terms of the
reduction on sludge volume in comparison to a HDS plant.
For the above reasons, this initially-appealing concept is not considered further below.
8.4 Option 1: Do nothing
In all analyses of this type, it is always appropriate to consider the status quo as a key option for the future: after all, it
has (by default at least) been the de facto preferred option up till now. Factors which might be cited in favour of
maintaining the status quo (i.e. making no further interventions to remediate the mine water discharges) include:
• the lack of any need to acquire and disburse further monies
• the lack of any need to expend time and effort in developing and maintaining a coalition of individuals and
organisations with a common commitment to developing and sustaining a remedial strategy for the pollution sources
All of the above appear to represent cost savings when compared with all other options. However, it is necessary to be
clear that the “do nothing” option does in fact entail substantial hidden costs. Chief amongst these are the following:
• the continued absence of a salmonid fishery in the Avoca River, which is estimated to have an annual-recurrent value
(in terms of licence revenues etc) of at least €750,000 per annum (Indecon, 2003).
• the substantial costs associated with fines and legal expenses which may well be incurred by the responsible
governmental agencies in the future, in the event that the European Commission takes action over non-compliance
with the Water Framework Directive and / or the Dangerous Substances Directives and derivative legislation.
• The value of increased tourism which might be anticipated in the wake of a substantial clean-up of the Avoca River.
• The value of educational and research activities at the site, which would bring revenue into the valley.
8.5 Option 2: Completely active treatment
8.5.1 Introduction
Active treatment can be defined as any process that requires a continuous input of resources to achieve the required
improvement in water quality. Unlike passive treatment, in which all the necessary resources are provided during
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construction, active treatment tends to require a reduced initial input but the continued introduction of chemical reagents
and manpower to maintain ongoing treatment. An active system is typically cheaper to build than a passive plant, but the
annual operating costs are higher. Because of the ongoing resource commitment active treatment tends to be used only
where other constraints prevent the use of passive treatment, such as a lack of suitable land to facilitate treatment and/or
difficulty of treatment due to chemistry of the mine water.
The mine water discharging from both the Ballymurtagh and Deep Adits has been characterised as net acidic and the
treatment of this water is required to both raise the pH and render the dissolved metals insoluble. The precipitated metals
are then separated from the treated water for long-term disposal. Following solid/liquid separation the treated effluent is
either discharged directly into the receiving watercourse or discharged via a filter to removal any the residual solids.
Active treatment at Avoca will therefore require the following stages:
• Addition of reagent to raise the pH (neutralise acidity) and render the metals insoluble.
• Separate the solids from the liquid.
• Sludge storage/disposal
The selection of reagent and configuration of the plant to allow optimum treatment is site specific. Based on the limited
data available for the Avoca mine discharges the following treatment strategy is proposed.
8.5.2 Treatment requirements
In addition to the design acidity loading specifications set out in Section 8.1.4., the design of active treatment plants
ideally demands consideration of key individual metals, which have different pH requirements for rapid removal in such
plants. Table 8.2 summarises the assumed specifications for active treatment design purposes, and Table 8.3 outlines the
anticipated effluent quality which can be achieved using the proposed active treatment process.
Table 8.2 Mine water treatment plant influent parameters
Parameter Ballymurtagh Deep Adit Combined Flows
Peak flow (l/s) 35.3 37.3 72.5
Average flow (l/s) 17.1 17.7 34.8
Fe (mg/l) 154 48.0 100
Zn (mg/l) 22 47.0 35
Al (mg/l) 52 106.0 79
Sulphate (mg/l) 1760 1260 1499
Table 8.3 Assumed Mine water treatment plant discharge parameters
Parameter Assumed Discharge Parameter
Annual Ave Peak
Fe (mg/l) 2 5
Zn (mg/l) 0.5 1
Al (mg/l) 2 10
Mn (mg/l) 1 5
Sulphate (mg/l) Not applicable Not applicable
8.5.3 Reagent selection
The choice of reagent used for pH adjustment is dependent on the target pH, ease of handling, local availability and cost.
To allow the effective removal of metals from both adits an operating pH of about 8.5 will be required (i.e. an operating
range of 8.25 to 8.75).
• pH adjustment is typically undertaken using either lime or sodium hydroxide or less frequently carbonates.
• Sodium hydroxide is normally supplied as a liquid and therefore is easy to use, though H&S implications have to
be considered. However due to its relatively high cost its use is limited to low demand applications, where the higher
reagent cost is offset by the reduced cost of the storage and handling equipment.
• Lime (either quick (CaO) or hydrated (Ca(OH)2) tends to be used for high demand applications as the lower unit
cost offsets the capital cost required to install a silo and lime slurry preparation plant.
• The use of carbonates tends to be restricted to the treatment of mine waters containing only iron due to the large
reagent dose required to raise the pH above 7.
The predicted reagent demands for the Avoca discharges assuming a net acidity of 12g/s are:
Reagent Average Dose Annual Demand Unit Cost Euro Annual Cost Euro
NaOH 10.7g/s 680tonnes 330/tonne 224,000
Ca(OH)2 12.7g/s 800tonnes 160/tonne 128,000
Based on the above cost analysis the use of lime offers a significant cost saving and is therefore recommended as the
preferred treatment reagent (the estimated cost for the lime plant at Avoca being approximately 200k ).
8.5.4 Sludge Disposal
Unlike passive treatment, the metal precipitate produced from an active plant cannot be retained within the plant and
therefore must be taken off site for disposal. The cost of sludge disposal is dependent on the mass of dry solids produced
and the moisture content of the sludge and proximity to the disposal site.
Sludge produced from a conventional mine water treatment plant (figure 9) typically contains between 3 and 5% solids,
the remainder being water. To dispose of 1 tonne of metalliferous sludge at a solids content of 5% would result in the
disposal of 50 kg of metalliferous waste (at 100% dried solids) and 950 kg of water or to dispose of 1 tonne of actual
metalliferous waste at 100% dried solids would require the disposal of some 20m3 of liquid sludge, making sludge
disposal without additional treatment expensive. The volume of sludge can be reduced by either physically dewatering
the sludge or by operating the plant in High Density Sludge mode.
Figure 9 Conventional mine water neutralisation plant
The sludge produced from a conventional mine water treatment plant can be dewatered to around 30% solids using an
automatically operated centrifuge thereby reducing the volume of sludge produced to approximately 4m3 per tonne of
solids produced. Installation of centrifuge on a treatment plant of the size necessary to treat the Avoca flows would
involve a capital cost of around 150k plus increased operating cost.
Similar sludge densities can be achieved by operating the plant in High Density Sludge mode. To achieve this it is
necessary to undertake the reaction in two stages and recirculate part of the resultant sludge as shown in figure 10. The
sludge produced from the plant typically contains about 15 to 20% solids and can be further dewatered in small gravity
drying beds to between 30 and 50% solids. On this basis between 2m3 and 4m3 of sludge would be produced for every
tonne of metal hydroxide precipitated. It is therefore recommended that any active treatment plant installed at Avoca
should operate in high density sludge mode.
Figure 10 High density sludge mine water plant
Indicative sludge masses and resultant Sludge Volumes are:
Table 8.4 Estimated Annual Sludge Production
Plant Annual Sludge Annual Sludge Volume (m3)
30% solids 50% Solids
Avoca Adit 780 tonnes 2,000 1000
Ballymurtagh 720 tonnes 1,900 1000
Combined 1500 tonnes 3,900 2000
8.5.4 Proposed Plant Design and Location
Although it is feasible to install separate plants to treat each adit the installation of a single plant treating both flows offers
a significant saving in capital and operating costs. This would however require the installation of pipeline under the river
and possibly a remote pumping station at the adit portal. Issues of pipeline maintenance would also need to be addressed,
which (as discussed briefly in Section 8.3.5.2 above) can be considerable where ochreous mine waters are concerned.
Sufficient land is available at both adit portals to allow the construction of an active treatment plant located with a
building to provide weather protection. Better access is available to the derelict land immediately downstream of the
Ballymurtagh adit, therefore the preferred location to construct a plant to treat the combined flows would be the
Ballymurtagh site. Lying downstream from the Deep Adit, this location might also offer the prospect of mine water
transfer from the latter location by pipeline gravity flow.
The proposed active treatment plant would be based on the schematic arrangement shown in figure 10 and would
comprise:
• Stage I reactor tank in which the mine water is mixed with the recirculated sludge to raise pH to between 7 and 8
• Stage II reactor in which lime is added to complete the precipitation reactions, together with air to ensure full iron
oxidation
• Lamella clarifier unit to separate the precipitated solids from the treated water
• Lime storage silo and lime slurry preparation tanks and pH controlled dosing pumps
• Flocculant dosing system
• Operators control room
• Sludge storage beds to allow the excess sludge produced by the plant to fully drain prior to off site disposal
8.5.5 Indicative capital and operating costs
The estimated construction cost for two separate plants to treat the adit flows is about €1,800k per site (i.e. €3,600k in
total) and the cost of building a single plant to treat the combined flows (including a pipeline across the river and
collection head works etc.) is about €2,500k. These costs are only budget estimates and at this stage do not include an
allowance for detailed design, planning, land purchase, etc.
Table 8.5 Active treatment plant indicative annual operating cost
Avoca Deep Adit Ballymurtagh Combined Plant
Power 11k 11k 17k
Lime 74k 56k 128k
Flocculant 6k 6k 12k
Potable Water 1k 1k 1k
Maintenance labour 6k 6k 6k
Maintenance spares 5k 5k 7k
Maintenance consumables 1k 1k 1k
Operator Labour 60k 60k 60k
Other Costs 2k 2k 2k
Sludge Disposal 10k 10k 20k
TOTAL 160k 144k 254k
The operating costs summarised in Table 8.5 have been built up on the basis of the following assumptions:
• Reagent costs (lime, flocculant etc.) are similar to the UK.
• Staffing is based on an operator being on site 8 hrs per day weekdays, with unmanned operation at all other times.
• The sludge disposal cost is based on a unit rate of €5/m3 to cover haulage to a disposal cell either in the abandoned
open pit or at a landfill. No allowance has been made for landfill gate fees etc.
8.5.6 Summary
Based on the limited data available it appears feasible that the flows from the Ballymurtagh and Avoca deep adits could
be treated in either separate plants, or a combined plant, in both cases using lime as the reagent. A combined plant would
be best located on the area of land immediately downstream of the Ballymurtagh adit, with the flow from the Avoca Deep
Adit piped across the river. Sludge from the plant could be dewatered in simple drying beds prior to ultimate disposal
(preferably by dry entombment in the abandoned Avoca pit).
The estimated cost of constructing the plant is approximately €2,500K with an indicative annual operating costs of
€254K.
8.6 Option 3: Completely passive treatment
8.6.1 Passive treatment technologies applicable to Avoca-type waters
Passive treatment is an increasingly attractive option for the long-term treatment of abandoned mine waters, such as those
at Avoca. Not only can passive treatment achieve major improvements in water quality, it also entails creation of pleasant
features such as ponds and wetlands, which enhance both the habitat and amenity value of the former mine site. Detailed
guidance on the selection, sizing and installation of passive treatment systems has recently been published (Younger et
al. 2002), and this report draws directly upon that guidance.
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For strongly acidic mine waters, such as the Avoca waters, the most efficient passive system configuration calls for:
• neutralisation of acidity in reducing and alkalinity-producing systems (RAPS), followed by
• polishing of the RAPS effluent in sedimentation ponds and aerobic reed beds.
Figure 11 shows a schematic cross-section through a typical RAPS unit, in which acidity is neutralised by two
processes:
• dissimilatory bacterial sulphate reduction in the compost layer, and
• carbonate dissolution in the limestone gravel layer
Figure 11 Schematic cross-section of a typical RAPS unit used to treat acidic
mine waters (after Younger et al., 2002).
Because of the limitations imposed by reaction kinetics, any one RAPS unit is only capable of neutralising a maximum
of 250 mg/l of total acidity (as CaCO3 equivalent). (In practice, neutralisation capacities closer to 150 mg/l are often
observed). Where the total acidity of the water to be treated exceeds this threshold, two or more RAPS units must be used
in series, separated from one another by sedimentation ponds sized to have at least 8 hours retention time.
8.6.2 Application of passive treatment design concepts to the Avoca waters
Using the design acidity values derived in Section 8.1.1., it is clear that for each of the two mine waters, at least three
RAPS units in series would be required. For the stated flow rates (25 l/s), the limestone gravel portion of each RAPS unit
would need to occupy 2520m3 (assumes typical 50% porosity of end-tipped gravel). If the bed were 0.5m deep (as is
usual), this implies that each RAPS unit would need to occupy a land area on the order of 5040 m2. This means that the
RAPS units alone would require on the order of 15,120 m2 at each of the two sites, to which would have to be added a
similar total area for sedimentation ponds and aerobic wetlands. In summary, therefore, satisfactory passive treatment of
the two principal adit discharges would require the use of some 3 ha at each of the two sites (6 ha total), which is far in
excess of the land area thought to be available (i.e. about 1 ha at each of the two sites; Section 8.2.1). It therefore appears
that completely passive treatment is not a feasible option for the Avoca sites, given the likely available land.
8.6.3 Theoretical costings for passive treatment
As a somewhat hypothetical exercise, supposing the necessary land was to be made available (by some means not
known), what would the passive treatment option cost to construct? From a compilation of costings for similar systems
in the UK, the capital cost of constructing each of the two necessary systems is on the order of €2.3M, or €4.6M for both
of the systems required. Thus, even if the passive treatment option were feasible, it would be likely to cost around 30%
more than the active treatment plant to construct.
8.7 Option 4: Hybrid passive-active system
Notwithstanding the above deliberations, which demonstrate beyond all reasonable doubt that passive treatment cannot
on its own provide the required solution to the Avoca discharges, it remains worthwhile considering whether some of the
benefits of passive treatment can be incorporated into an active treatment design. In principle, this can be achieved, not
only by sensitive design of active plant reactor exteriors, but also by including a small polishing aerobic wetland at the
end of the active treatment system, to remove any residual iron / suspended solids from the water before it enters the
river. This would serve to provide an “ecological buffer” between the treatment plant and the river, which would be more
in keeping with the riparian setting. Full costings for this option cannot be developed in the absence of site-specific
topographical survey data, but it is unlikely to add more than about €45K to the cost of each treatment plant (or to the
cost of a combined active treatment plant).
8.8. Preferred option
The most promising option is clearly active treatment. If this were combined with a polishing wetland, some of the
ancillary benefits of the passive treatment option could be added to the active treatment approach, at relatively modest
additional capital cost, and adding almost zero further maintenance requirements.
8.9 Further data requirements to support confident design and costing of preferred option
The magnitude of the capital spend suggested by the foregoing estimates (especially Section 8.5.5) is of sufficient
magnitude that the prudent budget-holder would be well-advised to make sure the somewhat scattered and interpolated
data upon which these calculations have necessarily been based are in fact consistent with present realities on site. To
this end, a programme of hydrological and hydrochemical monitoring is proposed (which can hopefully be implemented
by the ERFB) in order to yield at least one year of complete, synchronous and consistent data prior to the final design of
long-term treatment works. With this in mind, a monitoring regime for the study area is proposed in Section 9.4 below.
Site surveys for the likely parcels of land suitable for installation of treatment works have already been advocated above,
and will be essential to the detailed design of final works.
8.10 Towards a robust cost-benefit analysis of the case for treatment
Once these (and other) data are available, a full cost-benefit analysis of the case for treatment should be possible. Given
the estimated €750,000 annual value of the salmonid fishery the Avoca River should become once treatment is
commissioned, it is not anticipated that the capital (€2.5M) and running costs (€254K per annum) for the treatment works
are likely to prove prohibitive for advancing towards a solution.
University of Newcastle University of Newcastle Restoring the A Restoring the Avoca River voca River
64
9. Conclusions and Recommendations
9.1 Future Work in Developing Stakeholder Engagement
Following from the information we have been given by various respondents to this phase of the research, and addressing
the concerns they have expressed we have identified the stakeholder actions that need to be considered in the
development of projects. Primary stakeholders in particular are enthusiastic to develop all aspects of this work, but will
need the continued professional input of secondary stakeholders for project delivery. We have identified the points at
which these intersect.
VADA
The residents and members of VADA are willing and active in development of actions around the mine site. Anything
happening should happen closely with them, and they should be at the core of decision making processes. They have a
track record at raising funds. An active engagement with members of the VADA group should be encouraged, and in
terms of local stakeholder engagement VADA representation will assist the executive decision making process.
Anglers / fishing interests
The anglers are very keen to become involved with any activities that clean the river. Some voluntary time can be called
upon in pilot programme development. In the long term a project which gets the river clean has significant economic
returns. It is estimated that the potential value of the recreational salmon and sea trout angling resource on the Avoca
system, could generate at least €750,000 per annum (Indecon, 2003). In order to achieve this water quality we have a
long way to go in terms of the river management. We need to key the interests of these people very closely with catchment
planning.
Economy thus created would provide more than adequate finance to support river guides /ghillies programme which also
takes full stewardship into consideration. We need to work with all interest groups to develop a partnership that is capable
of sustaining enthusiasm and commitment into the future. If the management of the mine water filters is considered in
the context of the wider catchment restoration then we have an economy with which to figure stewardship issues. The
wider programme creates the economy with which to address management and maintenance issues.
WCC
The Local Authority has identified their role in the needs of the catchment in terms of their Catchment Conversion Plans.
We intend to work with them to facilitate these actions. Especially in terms of:
• acid mine drainage at Avoca – mitigation / remediation;
• development of the integrated plans for the mine site
• tourism and recreation
• economic zoning
Further to these, in respect to the involvement of the Film Commission we would look to working with the Commission
within WCC to promote the unique visual aspects of the landscape of the mine sites. Propose that in conjunction with all
other initiatives we look to proactively engaging with these positive aspects in ways that promote other forms of use for
the sites.
IFI
Respondents with technical understanding of the problems or potential problems associated with IFI and other pollution
issues in the lower catchment may be recruited to a technical steering group. In the fullness of a catchment management
project the issues raised by respondents concerning these sites will need to be considered.
EPA
Even if there is no current statutory obligation on the part of EPA their involvement is vital to the success of the project.
DCMNR
Concerns expressed by respondents at DCMNR, particularly about safety of the sites must be taken into consideration.
Exploration permitting over the area is the responsibility of the EMD. Afull risk assessment of health and safety concerns
will need to be carried out as a part of the continuing project.
There is sufficient enthusiasm within the geological confraternity within GSI to carry forward significant works of
interpretation for the open geology and the mine sites in general.
“Mining gets a bad press!” Being visibly involved in a clean up operation will give significant positive public image to
the mining sector.
Problems of ownership are finally being addressed. In the light of the expected publicity from the publication of this
report as a staging post to further developments there is an urgent need to bring issues surrounding receivership,
ownership of land, etc. to a satisfactory conclusion. Actions will also need to be taken to source the necessary funding to
put the issues of AMD right so as to develop the economy described here.
DÚCHAS
Respondents from Dúchas are keen to work with the development of plans for remediation. The important issue of
dereliction at other important mining sites in the catchment has been noted. In the likelihood of initiatives that address
heritage aspects at Avoca it would be important to key with conservation of other important heritage mining sites.
East Coast and Midland Tourism
Personnel need to continue to key with all project developments. ECMT will be able to provision advance projects with
the necessary integration with wider tourism infrastructure concerns.
MHTI
Heritage Trust members have a continued stake in the development of the mine site. They would be interested in
developing tours. And these could include underground tours. Along with VADA and GSI they have a wealth of
information and understanding of the site, its history, its importance, etc. These will need to be collated and developed
in the context of the development of interpretation and education around the mine sites. Main area of concern here is the
need for adequate provision of health and safety assessment and insurance. (see photo 12 page 52)
ERFB / CFB
Fisheries Board personnel have a strong commitment to the development of this project. There is a need to galvanise this
commitment into concerted action. Some members will need to continue to monitor flow rates and water chemistry.
Landscape Concerns
Respondents have identified the need to consider the uniqueness of this landscape. We will need to develop a programme
of work which gives full consideration to this concern. We need to develop the tools to measure the importance of this
landscape, and celebrate its difference as a potential attraction. We need to consider whether the landscape is worth
conserving, and why. A full evaluation needs to be undertaken.
Partnership Development
Partnership working is about sharing resources and understanding. There is a need to continue to collate all of the above
understanding and consolidate it in a form from which action can be developed. There is a need for definition of
partnership. Who will do what? Who will take what responsibility? This is something that cannot be predetermined, but
will define itself and emerge over time. In saying that it is important that the aims and objectives of a partnership must
be clearly defined.
Water and Ochre
There are two physical products in the project we are proposing: clean water and ochre. The ochre continues to be a
problem if we need to address problems of its disposal. It is our strong recommendation that we develop a research
programme which looks at the reuse of this material. The ochre thus becomes not a waste product but a product. We are
working with research in the UK into the understanding of this material in its potential use. Some of this research is being carried out with colleagues at Parys Mountain in Wales. In the wider scheme of partnerships this research could serve as
a focus to define a broader partnership with Parys and other abandoned mine sites.
9.2. Identifying and securing funding
There is a pressing need to develop pilot programmes that will define costs. What will a full intervention cost? Who will
bear the brunt of these costs?
We are looking at alternatives to interventions which only look at the mine water problem and treat this in isolation. We
understand that a much wider range of objectives can be considered in a broader package that encompasses all of the
issues under consideration. Finding funds to develop one part of a programme, for example education and research, can
lead to implementation of the wider programme taking all issues into consideration. We therefore suggest that all of the
issues identified (and others that may come to the fore) are racked together so as to maximise potential of funding. This
will need considerable dedicated time to pull together.
Respondents have identified potential funding from a range of public and private sources, the latter perhaps motivated
by the value of the restored salmonid fishery which treatment of the mine waters is confidently expected to yield.
There may be funding available to Wicklow County Council under the Water Framework Directive River Basins
Management Project.
There is a wide range of funding opportunities available from various programmes. Financial assistance from the
European Programme INTERREG Ireland and Wales, which is meant to “encourage partnerships across borders and in
doing so to stimulate regional development”, is clearly an attractive option. The organisations intended to benefit include:
public bodies, educational establishments, voluntary organisations and local action groups, community groups and the
private sector. The six objectives within this call are:
• Promote the sustainable use of natural resources
• Protect and enhance biodiversity, seascapes and landscapes
• Invest to enhance the capacity of the area and its people to support sustainable development
• Promote active community participation in sustainable development
• Enhance knowledge and understanding of sustainable development
• Promote the use of sustainable development indicators and monitoring
We understand our programme to include any and all of these objectives. INTERREG Ireland and Wales also includes
programmes for the development of small to medium enterprises.
9.3 Site survey information requirements
As mentioned in Section 8.2.1., advancement of designs for treatment plants must include detailed topographic level
surveys for the areas of land potentially available for treatment, including the parcels of land adjoining the two adits and
the Tigroney Pit. In addition, it is recommended that a specialist in quarry safety (whom we can recommend if necessary)
be asked to inspect the Tigroney Pit and recommend the steps necessary to make the unflooded areas of the pit floor safe
for development of educational facilities.
9.4 Hydrological and hydrochemical data collection
We propose the installation of thin-plate weirs or flumes to capture the entire flows from the Ballmurtagh and Deep Adit
portals. Digital water level loggers (we recommend the DiverTM variety) should be placed behind these and set to read at
15 minute intervals. Every fortnight, the data from these loggers can be down-loaded and the weirs cleaned to make sure
the readings are accurate. This will yield virtually continuous flow records for the two main discharges.
At the time of the fortnightly logger maintenance visits, water samples should be collected at the following points:
Deep Adit
Ballymurtagh Adit
Avoca River at White’s Bridge
Avoca River at Avoca Village
On-site measurements should be made for pH, temperature and conductivity. The retrieved samples should be analysed
in the lab for: Ca, Mg, Na, K, Fe, Mn, Al, Cu, Zn, Cd, Ni, Pb, As, Cr, Sr, SO4, Cl.
Finally, at the same fortnightly interval, we recommend that the flow of the Avoca River be spot-gauged (probably using
a wading impeller set) at Avoca Village. A staff gauge should be fixed in the river at the gauging point (and the level
recorded whenever visited), and a water level logger installed in a simple stilling-pipe to log water levels at 15 min
intervals.
9.5 Proposed forward programme
In the past decade a number of important studies were undertaken including the EU supported report under the LIFE
Programme. These have identified the chronic pollution emanating from a site, which is believed to be in the control of
the state. Whether the state owns the mine site or not, Ireland has a duty, to ensure that those who are responsible take
the necessary measures to ameliorate the problem. Where this cannot be done, Ireland must for the protection of the
environment and its people take the steps to remedy the situation.
It should also be noted that the toxic effect of the acid mine drainage is not restricted to plants and lower animals it is
also detrimental to livestock and humans. The value of this river once restored would be enormous to the local
community bringing economic, tourism, social and cultural benefits.
9.5.1 Development of monitoring programme and progress towards detailed design
It is proposed that the survey data (Section 9.3) be collected by Wicklow County Council, who no doubt have an in-house
surveying team.
The hydrochemical and hydrological data (Section 9.4) are anticipated to be collected by ERFB. Weirs will need to be
installed at the two adits (something which has been undertaken before by staff of TCD and GSI, who may be willing to
assist with this task) and a staff gauge in the Avoca River. This should be done as soon as possible, as the collection of a
full year of data cannot commence till these facilities are in place.
We recommend that on-site treatability trials be undertaken during the year of monitoring, in order to confirm:
• Reagent consumption for treatment of the Avoca waters
• Settlement criteria to allow optimisation of plant size
• Confirmation of final effluent quality.
(Such trials were undertaken at Wheal Jane and proved crucial to the final design and procurement of the long-term
treatment system now installed there).
At the end of the year, the partnership should commission competent process engineers to prepare tender documents to
allow competitive bidding for the construction of the treatment plant(s).
9.5.2 Partnership Development
The principal concern of partnership development is inclusion. Participation by those ultimately affected will be limited,
and / or the participants will be unrepresentative, if some or all of the affected persons lack the power to organise and get
themselves fairly represented. Participation of all or some of those affected may not be in the interests of other
stakeholders.
After presenting this report we hope to continue to involve the stakeholders so far canvassed, and others, in the full
realisation of the project. It has been suggested that the report is circulated prior to convening a joint meeting of these
stakeholders. We envisage this as a form of focus group or series of focus groups, outlining all concerns and scoping all
possibilities afforded by potential engagement with the long term core project objective – the remediation of the Avoca
mine waters, with means to their development through engaging with other key objectives – the development of the mine
site, environmental conservation, including conservation of the mine buildings, education and research, broader
partnership, and so on.
It is expected that a core group of interested stakeholders can be established around these actions that would be capable
of carrying these proposals forward. We would further expect to develop an understanding of cost benefits, and source
core funding for project development, and all risks associated with further undertakings. Understanding can, and should,
be progressed through pilot actions on the ground, in order to sound out the practicalities of partnership working.
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APPENDIX I
The broader picture of extensive mineralisation in the Avoca catchment
“Wicklow is the premier county in Ireland for mines, not only on account of the ores
being very rich, but in consequence of the great extent of the mineral ground, and that
the mining operations have been in varying activity at intervals from time
immemorial” (Kinahan 1889, p.109).
The whole of the Avoca catchment is rich in economic minerals. The importance of these has been known for centuries. While
one might argue that only the geology of the workings which are drained by the Ballymurtagh and Deep adits should strictly be
discussed here, we believe the case for fully respecting the mining heritage of the district when developing any programme of
remediation can only be fully made if some appreciation is gained of the full extent of mineralisation in the catchment.
As long as there has been metallurgy there has been mining, and many of the minerals found in the Avoca catchment have been
in use by humans for a very long time. These were listed by Kinahan in collected papers in the Journals of the Royal Geological
Society of Ireland, and collated into one exhaustive volume in 1889. We add to his lists the observations of other authors, mostly
working in the same period.
Kinahan (1889, p.109) offered the following sketch of the main belt of mineralisation in the Avoca Valley: the “Great Mineral
Channel extends from near the sea southwards of Wicklow, in a south-west direction, to Ovoca, and from that to the flanks of
Croghan-Kinshella, a distance of about fifteen miles. In the channel and adjoining it the rocks are ‘iron-masked’, similar to the
rocks adjoining to the intrude [sic] of the younger Granite …”. Kinahan appears to have considered that the mineralisation is
genetically linked to the igneous activity which accompanied intrusion of the younger granites. Kinahan especially notes that
“in places along the Channel there were very ancient mining operations”( loc cit).
Gold is noted as occurring in the Avoca catchment in:
• the gravels of the Darragh (Derry) Water, Aughrim River and its tributary rivers, namely Goldmine Valley
and its tributaries, Kilacoran Stream, Coolballintaggart Streams, the Valley of the Ow and its tributaries, and
the Killmacreddan Burn; at Castlemacadam in the gravels of the Avoca River south of the railway station;
• veins in the metamorposed Ordovician by the Aughrim River at Ballymanus; in the gossan of the Avoca
mines namely Ballymurtagh, Tigroney, Cronebane, Connary, Kilmacoo, Balycoog, Ballynasilloge, and
Moneyteigne. The gossan zone of East Cronebane (Magpie Mine) seems to have been richest. The
‘Kilmacooite’ of the Kilmacoo and Magpie mines are also noted as auriferous. (Kinahan 1889, pp 9 - 10).
And “…at Ballymurtagh … the copper ore (coppery pyrite) is in part auriferous, while most of the coppery
lodes in the great Ovoca channel probably contain some gold”( Kinahan 1889, p. 26).
Copper: The following records of copper occurrence are notable:
• “Copper is recorded as having been found native in the mines at East Cronebane and Connary in cracks or
slight shrinkage fissures in the veins, while the mine water has deposited it on the metals in the old workings”
(Kinahan 1889, p. 26).
• Copper is also noted at Lough Tay and Lough Dan, where it occurs together with lead and zinc; at Glenmalure
mines, in the lead mines at Ballynagoneen, Camenabologue and Ballynacarrig Lower; at Aughavannagh, in
the ‘ancient mine’ at Moneyteigue; at Tinnaheley with iron ochre and malachite; at the Carysfort Mines of
Woodenbridge - Ballinagore, Ballinvalley, Ballycoog, and Ballynasillogue, in association with iron and
sulphur ore; the Southwest Ovoca or Knocknamonhill Mines of Knocknamonhill, Ballinapark, Killeagh and
Ballymoneen, where the old mines were worked for iron; in the West Ovoca or Ballymurtagh Mines -
Ballymurthagh, Ballygahan (Upper and Lower), Tinnahinch, Kilqueeny, Kilcashel and Knockanode where
the old mines were worked for copper, sulphur ore and iron; at the East Ovoca or Cronebane Mines -
Tigroney, Cronebane, Castlehoward, Avondale (Meetings), Shroughmore, Connary Upper and Kilmacoo,
principally for sulphur ore, copper, iron and ochre, the latter two also for lead; (Kilmacrea, Templelyon and
Ballykean, sulphur and iron ores); and the Ballycapple Mines at Ballycapple and Ballard worked about 150
years ago [i.e. 15o years prior to 1889] for iron ore. (Kinahan 1889 pp 34 - 35).
Sulphur: The sulphide minerals in the mining setts of the “mineral channel of the Ovoca Valley” (Ballycappel Mines,
Kilmacrea Mines, East, West and South West Ovoca Mines and Carysfort Mines) are have been worked for
their sulphur content, particularly during periods of war. “Some of the best of these, however (in olden times),
were worked solely for the copper in them” (Kinahan 1889, p. 38).
Barytes: At Baravore in the Glenmalure Mines, found “with lead and zinc, very pure” (Kinahan 1889 p. 39).
Iron: Metamorphic Ordovican Limonite: the backs of copper and sulphur ore lodes. Very ancient workings appear
to have existed at Carysfort Mines (Moneyteigue, Ballycoog, Ballynasilloge), Woodenbridge; at Arklow (“a
large ferriferous mass”); SW Ovoca mines worked in 17th C, with ore being sent to Chamney’s furnaces at
Ballynaclash and Shillelegh; Ballymurtagh; East Ovoca Mines, noted to be actively working ochre in 1889;
Templelyon: and at Ballycapple and Ballard, limonite, magnetite, chalybeate and ochre, had extensive 17th
cebtury works, the ore smelted by Chamney in the Vale of Clara at Ballynaclash furnace, the old mines were
(in 1889) still called the ‘Clash Pits’. According to tradition, after the O’Helys were driven out the Normans
built castles here and worked at the iron trade. In Elizabethan times the Earl of Stafford (aka Black Tom) and
later his successors, mined and worked iron. Their iron masters were the Paynes, the Bacons and the
Chamneys (Kinahan 1889, p. 109). The Bacons extended workings at Shillelagh. The Chamneys at the Vale
of Clara, Ballynaclash, or ‘Clash’ in Glenmalure, Garrynagowlaun (Woodenbridge), and Aughrim, as well as
innumerable bloomeries. Clash and Shillelegh iron was of a very superior quality; Kinnahan notes “a pound
of ‘Clash Iron’ being exchanged for three pounds of the ordinary iron at present in use” (Kinahan 1889, p.
110). In the townlands of Ballycapple and Ballard the ‘iron back’ of the Ballycapple Sett lode was worked by
the Chamneys. Some ore was smelted in bloomeries in the vicinity of the mines; the bulk of the ore was
carried on horseback to Glenmalure. The iron trade ended here around 1761 as a result of a dispute between
Chamney and the English agent of the lord of the soil. The presence of high grade iron and smithing
techniques is noted as an important factor in the capacity of South Wicklow insurgents to arm themselves in
1798. We note here, from miscellaneous manuscripts held by VADA the local interest in Thomas Brady, the
chief mines clerk at Cronebane, who was a captain and key figure in the United Irishmen: transported to
Australia at the assizes of 1799. The Avoca miners were lively in the political arena of that period. In 1798
Sir John Parnell, suspecting a United Irishmen plot at the mines, spoke in Parliament against the practise of
recruiting miners into the militia describing the Avoca miners ‘a most dangerous body of men to the peace of
the country’.
Antimony: occurring as the sulphide, stibnite, associated with lead (galena). At Cronebane and Kilmacoo.
Graphite: North East of Rathdrum; Avondale; Cronebane.
Silver: Camaderry, Glendalough lead Mines. “Associated with the lead of this lode were found some handsome
sprays of native silver; also the peculiar form of calcite, called Schiefer Spar”( Kinahan 1889, p. 479).
Lead and Zinc: Found grouped together sulphides of lead (galenite), zinc (blende or sphalerite), and iron (pyrite or sulphur
ore), and more seldom the sulphides of copper (chalcopryte), arsenic (arsenopryte or mispickel) and antimony
(stibnite) with baryte (barite). The lead ore is often argentiferous (Kinahan 1889, p. 13). Found in Wicklow
in the Douce Mountains Powerscourt, and [?] Glen of Hollywood. Also Lough Tay and Lough Dan - Tougher
and Carrigeenduff; Boleylug, or Moatamoy; Shillelagh; Carrigroe (“an ancient mine”); Glendalough Lead
Mines - Brockagh, Lugduff, Camaderry (Luganure and Glendassan are su-denominations of Brockagh);
Glenmalure Mines - Lugnaquilla (North Prison), Ballinafunshoge, Ballinagoneen, Ballboy, Baravore,
Camenabologue, Clonkeen, Clonvalla, Corrasillagh, Cullentragh Park and Ballinaclash; Aghavannagh near
Aughrim; Ballintemple and Clonwilliam [sic] at Woodenbridge; Killmacrea; and the E Ovoca Mines of
Stroughmore, Kilmacoo, Connary and Cronebane.
APPENDIX II
Mining history
“All aspects of the Vale’s history are influenced and connected with its mining heritage” (Merrigan).
As with other globally important mineral and mining districts, no contemporaneous documentary evidence of ancient mining
activities has survived. However, there are sources which can be drawn upon to bolster the necessarily speculative understanding
of the vast antiquity of mining in the Avoca area.
It is certain that gold, silver and copper mines were worked in this area from the remotest antiquity. It is also known that gold
was obtained here in much greater abundance in ancient times than it is found today (Joyce, 1913.554). The skills of the pre-
Christian artists and metalworkers are widely recognised.
Ptolemy attempted to map the known world, and in 150 AD in the otherwise relatively obscure territory of Ireland, indicated the
location of ‘Oboka’. Its fame in that period can only have come from its economic importance.
The region has little native tin, which is a key constituent of bronze. Early Bronze Age commerce with Cornwall would almost
certainly have been established. Ireland had natural materials available to early Bronze Age metallurgists, notable areas being
Avoca and West Cork Mount Gabriel mines where remains of ancient mines have been identified (Herity and Eogan 1977;
O’Brien, 1996).
By the time that Saint Patrick arrived in Ireland the art of working bronze, gold and silver was already highly developed. The
native Irish were teachers of the industrious monks. Churchmen added crosses, chalices, bells and shrines to the existing stock
of military artworks: swords, shields and brooches. The date of the Milesian king Tighernmas, the first to smelt gold, through
the agency of his artificer Uchadan, is located as 939B.C. (Joyce 1913.69). Joyce further affirms that this proves that the mines
of Wicklow were “as well known in the far distant ages of antiquity as they were at the end of the eighteenth century” (op cit.
i,.554). Power (1989) notes earlier mining activities: a standing stone near Rathdrum marks the location of a megalithic ‘flints
factory’. Merrigan draws inference from the Bronze Age burial cist at Knockenree of the area as a thriving industrial centre.
It may be further worthy of note that Tighernmas introduced hierarchic differentiation at his court through the regulation of the
wearing of colours. This may provide circumstantial evidence for the understanding and use of native earth dyestuffs. We are
aware of the use of native earth dyestuffs and minerals as pigment in ancient times. Much of the material used to illuminate the
Book of Kells, for example, can be found within the Avoca catchment. We note the malachite greens which, through their acidity,
still etch through the vellum pages. As well as ochre stuffs providing reds oranges and yellows the exhibition area in Trinity
College exhibits a piece of galena from Glenmalure from which a luminescent scarlet red lead oxide is known to have been
obtained.
Kinahan (1889) notes the record of the Annals of the Four Masters, and includes the note that “at Lyra, Knockmiller, about two
miles southwards of Woodenbridge, Co. Wicklow, the ancient timberings in a placer mine were found” (p5). The earliest
workings of which traces can be detected were for lead in Cronebane, and iron in Moneyteigue. And “… at the Magpie or East
Cronebane (Ovoca), … there are ‘old men’s workings’ on the ‘gossan lode’, and in them were found stone and wooden
implements. Here native silver was also found” (Kinahan 1889, p 6).
At Connary and Cronebane ancient mining for lead and silver has bee proven by the finding of ‘old men’s workings’ containing
stones, hammers and other primitive implements, and at Moneyteigue iron workings. Ruins of very ancient iron workings and
mines are recorded between Aughrim and Ballynaclash.
Barnes, the mine manager at the West Avoca in 1864 noted evidence of ‘mining trials before the use of gunpowder or
mechanisation’.
The Avoca mines have worked a variety of minerals across history. From the 12th century, the site was mainly producing iron
but this had been exhausted by the end of the 17th century. Lead was worked until 1750, copper until around 1812, sulphur
between 1840 and 1865, and again intermittently until 1949, especially during the two World Wars. From 1958 till 1962 over 3
million tons of 0.6% copper ore (chalcopyrite) were produced, and between 1970 and 1982 a further 8 million tons. Gold, silver
and zinc have also been extracted but not in economical quantities. There have been recent unsuccessful attempts to extract gold
from the heaps.
Historically ochre was obtained for pigment use. The son of the 18th century mine owner discovered a process of preserving
wood in copper sulphate, describing this process as ‘Kyanisation’. As well as recovery from ore bearing rock by smelting,
copper was also recovered from the waters of the mountain by a process called precipitation (as used also at Parys Mountain,
Anglesey).
In 1956 the Mogul Mining Corporation of Canada under the name of St Patrick’s Copper Mines began mining with considerable
aid from the Irish Government. Production ceased in 1962 and a skeleton maintenance staff were kept on.
From 1970 to 1982 Avoca Mines Ltd worked the mines.
The area has remains of seven engine houses and a mineral tramway arch. Features of the East Avoca site include the Deep Level
Adit, from which the mine water drains. Nearby are the remains of recent ore storage bins and timber frames. On ascending the
hill the preserved remains of the Cornish engine house and chimney of Williams’ Shaft dominates the skyline. Above this there
is a wide area of dressing floors, and the remains of another engine house and chimney. The open Farmer’s Shaft is some
distance away on the right side of the road. Again further up the open Tigroney pit, Mount Platt and Cronebane open pit.
The mines office from 1950’s also survives, and was used to house elements of the EU LIFE project.
Other mine sites within the Avoca catchment which have significant remains are the lead mines at Glendalough and Glendasan.
The abandoned mine workings at these sites are easily spotted on account of the extensive white spoil heaps amongst the valley
side screes beside the Glenealo River, above the Upper Lake, and at the ‘miners’ village’ of Glendasan. Above this is to be found
‘Van Diemen’s’ mine, possibly named for its remote location. The granite rocks here are rich in quartz veins with silver, lead
and zinc mineralisation. Some levels connect the valleys underground, traversing from one to the other. These mines were
worked between 1795-1957, although the main period was 1850-1880, at which time over 2,000 people were employed. The
approximate output was about 60,000 tons of galena with some sphalerite.
APPENDIX III
Extracts from historical correspondence relating to Avoca River 1900-1931
Letter to Colonel Charles Bayly, Estate Office, Ballyarthur,Woodenbridge, Co. Wicklow from John H. Parnell
6th April 1901
............................ I hope you will excuse me not answering your letter sooner but I have been up to my head in law. I assure
you I will be only too glad to do all I can to help you on the scheme for keeping the salmon up the river. There is no use my
asking Mr. Boyland as we are at law. Now in reference to Avondale I suppose our case will come on about the end of the month.
Letter to Colonel Charles Bayly, Estate Office, Ballyarthur, Woodenbridge, Co. Wicklow from George Golden, 10 Westland
Row, Dublin
23 February 1902
............................ I called on Mason at his home on yesterday week and laid the whole matter before him. I laid Prof. Reynolds
report also before him and discussed the various schemes we have talked of. The pipe on the bed of the river he did not like as
being too costly in the first instance and liable to become blocked and therefore likely to be expensive to keep up. Filtering he
has objected to on the grounds that they would want a staff of men, constantly employed to keep them working.
He suggested an open trench or ditch alongside of the river from the mines to the sea. The impure water he said would have to
be collected above where it flowed into the river from the mines on one side and on the other side it would have to be brought
over in pipes from that side to the one on which it was found the trench or ditch could be most advantageous. The trench would
have to be concreted in the bottom most likely and when I had explained the distance and nature of the ground to be covered by
it to him he said that the cost would be about £20,000 to £25,000 he thought. This figure is of course only the wildest
approximation as he would not give an estimate until the ground had been surveyed. Another, and he thought, a cheaper scheme
would be to cover over the waste banks with clay and then on top of that plant shrubs and vegetation on it. He tells me that he
has done this before successfully and except for springs of water coming up from outside the banks he was quite sure it could
eventually prevent all surface waters such as rain from washing down through them, in fact that it was a way of sealing them
up. I told him that my investigations were purely irresponsible to anyone and entirely off my own bat and that before anything
could be done all the riparian owners would have to agree. I told him I believed they would if a workable scheme could be laid
before them but that in as much as it was at present nobody’s business I could not say whether the matter would go on and
therefore did not feel inclined to spend much money on preliminaries. He thought for a long time and then he said ‘as I
understand you doctor, you want a definite scheme and the cost of it before you approach the landowners’, ‘yes’ I replied ‘that’s
exactly what I want’.
Letter to Colonel Charles Bayly from A. V. Hood, Glenart Estate, Arklow, Co. Wicklow
25th October 1909
............................ I have yours of this date relative to the purification of the river Avoca and in reply I may say I am aware that
neither Lady Carysfort or Colonel Proby would entertain the question of any extra expenditure of money on their behalf for the
purpose.
I do not think it a time at present, in which any owners of landed property will be very ready to pledge themselves to carry outlay
of capital for a purpose of this kind whatever they may have expressed themselves willing to do in years past.
Letter to Lord Wicklow,(Earl of Wicklow), Shelton Abbey, Arklow, Co. Wicklow from Colonel Charles Bayly
16 March 1911
............................ I enclose you correspondence re River. You will see that all the riparian owners seem keen on some scheme
being put before them. The Glenart portion, the fishing rights might be bought up by yourself and Archie as they join the Estates.
If you think after reading enclosed that something might be done, I will write to the Trustees of Johnston Estate re the mouth
fishing and see what they would be willing to do. ……….. …
Of course the tenants have bought their land, I presume, any there are, would have to be approached to see if they would join
University of Newcastle University of Newcastle Restoring the A Restoring the Avoca River voca River
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in or sell their rights. Of course the owners affected go as far as Glendalough. The place I propose to make filtering beds is in
old river bed under Avoca Lodge.
Letter to Colonel Charles Bayly from Lord Wicklow
28th August 1911
............................ I am afraid it will be some time before we can expect to get anything in the nature of an authoritarian opinion,
but I pointed out to him that as the Government are large riparian owners it is much to their interest to find some means of
making the river passable for salmon.
Letter to Lord Wicklow from Dept. Fisheries (L.C. Moriarty, Secretary)
30th October 1924
............................ I am directed by the Minister of Fisheries to inform you that the Department is not prepared at present, to go
into the details of any scheme for the purification of the Avoca River, as there do not appear to be any funds available to carry
out the work, but that the general question is being kept in view and any information bearing on it is being noted.
Letter from Stanley Solicitors, Dawson St. Dublin to Colonel Bayly
23rd February 1927
............................ Mr. Green referred us to the Fisheries (Ireland) Acts 39 & 40 Victoria, Chapter 75, Sect. 5, which prevents
pollution of rivers, but the Section goes on to say ‘other than water in the same condition as that in which it has been drained
or raised from such mine’ and Mr. Green thinks that these words would prevent the riparian owners taking an action against the
mine owners for permitting this water to flow into the River Avoca.
Apparently the overflow is principally from two streams from the mines at Tigroney and Cronebane but unfortunately the
volume of water coming from these mines is 540,000 gallons per day and estimates have been received to the effect that it would
cost some £12,000 to pipe the overflow of these two streams to the sea.
The other alternative would be to erect a plant at the mines in question to purify the water and this plant has been estimated to
cost about £10,000 and would require a ton of lime per day and somebody in charge to keep the works running both day and
night would add very considerably to the expenses as the lime alone would cost £1 per ton.
From a legal point of view it would appear that the riparian owners have acquiesced in the pollution of the river from at least
1866 and a very serious question would now arise as to whether the mine owners have not established a right to permit the
overflow from the mines going into the River Avoca.
Mr. Green turned up the fill and found that he had a letter from your brother of 23/5/19 and a letter from C. Byrne T. D. on the
14th June and although the Minister of Fisheries would be very willing indeed to assist as far as possible he has no money
available for the purpose of preventing the pollution of this river but he might give financial assistance but for the fact that if
the river ceased to be polluted the revenue derived from the fishing would vest in the riparian owners and it is estimated
according to Mr. Green that these riparian rights should be worth about £3000 a year.
Having regard to the very great expenditure necessary to pipe the overflow to the sea, which is the only practical method the
question immediately arises whether this expenditure would be justified especially having regard to the fact that Messrs A & J
Robinson find the greatest possible difficulty in showing Mrs. Bateman’s title to the several fishery at the mouth of the river.
Letter to Colonel Bayly from J. R. Wynne, Glendalough, Co. Wicklow
29th May 1927
Says that he rec’d a letter from Dept. Fisheries saying that before anything could be done about the river, they wished to have
a further survey of the water from a chemical and biological point of view.
Letter from Dept. Fisheries (L. C. Moriarty) to J. Neill, Fishery Office, Enniscorthy, Co. Wexford
15th May 1925
............................With reference to the resolution passed by the Wexford Board of Conservators at their meeting on the 4th June,
in relation to the Avoca River. I am directed by the Minister to ask whether it is considered that the cost of the necessary works
estimated at several thousand pounds would be recoverable from the persons benefiting thereby and if so, under what sort of
arrangements.
Letter from J. Neill, Fishery Office, Enniscorthy, to Dept. Fisheries (L. C. Moriarty)
6th June 1928
............................ To state that the Dept. has no funds available for purchase of fisheries or for works on the scale necessary for
the purification of the Avoca River.
19th October 1928
Dept. Fisheries requested further info. On details of proposal referred to, particularly in relation to financial elements.
This was sent to them as follows;
............................ Will send this request to the Board of Conservators, in the meantime can their engineer estimate the probable
cost of a canal and aqueduct to take overflow from mines to the sea, and to advise the best line the canal should take.
It is now up to the riparian owners of this river from Lough Dan to Arklow to convene a meeting to ascertain their views in the
matter and also what financial assistance they are prepared to give towards this object. It is unnecessary for the Conservators,
to point out the financial gain it would bring to them. Salmon fishing is getting more valuable every year and once the poison
waste was removed from the river salmon would ascend freely.
Even now quantities of salmon are caught in a dying condition in and about Arklow. A few do get up in a very high winter flood
and salmon smolts are frequently caught by trout fishermen in the Aughrim river. This shows that the salmon only want the
opportunity of having clean water.
To purify the river it would be necessary to construct a canal and aqueduct from the old workings of the copper mines on both
sides of the river to take the poisonous water to the sea some two miles or so north of Arklow. When the question was mooted
some 40 years ago, the cost was estimated for the canal at £4,000. Without an engineers report it would be unsafe to say what
the cost would be today.
Letter to Col. Bayly from Sr. Langlis Lefroy, 23 Summer Place, Kensington, London SW7
22nd August 1930
............................ On Monday I was talking with one William Bury, who has lived in Cronebane from 50 years or more. He told
me that the discharge from the upper level has ‘always’ existed but he pointed out that in former days is was run out of the wood
into settling pits where the ochre settled and was cleaned out from time to time and the effluent was at least far less turpid?
Apparently the opening up of a few months ago released far more water and the present liquid absolutely glues up leaves, sticks
etc. into a solid mass in the ditches and gullets.
In any case the liquid in its present condition would be perfect filter to run into any pipe and I think would silt up before many
years. An open drain is the only possible solution unless where it were unavoidable in crossing below the river for example.
Letter to Co. Bayly from Alfred Delap, Delap & Waller, Chartered Civil Engineers, 115 Grafton St. Dublin
23rd February 1931
............................We think that the field work necessary should take less than a week, given fine weather etc. The report would
deal with the physical possibilities and negotiations with landowners, other than the Railway Company would not be included.....
We think it is essential to check the flow measurements as the design of flume and economy in the cost of the whole project is
largely dependent on the volume to be carried.
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REPORT BY DELAP & WALLER, CHARTERED CIVIL ENGINEERS
Avoca River purification – drainage of effluent to the sea
16th November 1931
Scope of report
Deals with the practicability of intersecting the poisonous effluent from the mines and the Avoca valley which
reaches the Avoca River between the meetings of the waters and Avoca town and the conveyance of this to the
sea by means of a flume, pipe or trench.
Principal sources of pollution
2 streams on east bank & 2 on west bank.
East bank – 1 flow from a level in the Castlehoward Demesne. This level drains much of the upper workings
of the mines, enters river at a culvert under the railway at a point just above the mine bridge
E. bank – flow from main adit
West bank – adit at Ballymurtagh – ocre works marked on map as ‘saw mill’
W. bank – drainage from the upper workings on this side of the river with much surface water added, finds its
way down the ‘red road’ to the river.
Quantities
Vary with rainfall & therefore these quantities were taken during ordinary wet seasons & heavy spells of rain.
Stream no. 1 Castlehoward .385 cu ft per sec
Stream no. 2 East adit .586 “ “
Stream no. 3 Ballymurtagh .403 “ “
Stream no. 4 Red road .456
Total 1.824
Contingencies – 50% .912
Total 2.730 cu feet per sec.
Means proposed
Propose to convey the quantity of poisonous water to Arklow by means of a conduit and discharge it into the
marshes which surround the sea on left hand bank below Arklow bridge. This conduit will for the most part
be a flume with specially treated metal pipes. Will flow the line of the old tramway to the sea. Outflow from
stream no. 1 will be through an open cut or channel to the main flume. (Same with other outflows – joining
flume at various points). Pumping station will be installed near the old sawmill (west Avoca).
Costs
Above works £13,455
Engineering £1,187
Total £14,642
Letter to Co. Bayly from Delap & Waller
2nd January 1933
………….. We have this morning had an opportunity of discussing the scheme we submitted to you in 1931 for the purification
of this river with Mr. Greene, Snr. Inspector of the Fisheries Dept. & Mr. Hossard, Engineer to the Dept. They went into all
details and we gather approved of the whole scheme as a practicable and effective solution to the problem.
It was when we came to discuss how the scheme would be put through that difficulties began to appear.
Mr. Greene pointed out that if a several fishery existed in the tidal waters the owner of this can use his powers to get all the fish
and deprive other riparian owners of any advantage and that if no several fishery exists, the public an fish in the tidal waters
above the half mile limit and again take all the fish to the loss of the riparian owners.
If the syndicate of riparian owners acquired any several fishery that may exist they might be able to get the Fishery Dept. to
make bye laws prohibiting all netting in tidal waters and in this case they would have the fishing rights upstream as far as their
riparian rights extend; but it would be necessary for them to preserve the river right up to and including the spawning beds if
the fishing was to develop satisfactorily.
It does not appear to be a promising scheme to put forward for Govt. help, as it would be of no direct public benefit and would
only be of advantage to the private owners. If the riparian owners are, themselves to put the scheme through there would have
to be very substantial agreement among them; any existing several fishery would have to be secured, a private bill would have
to be got through by the Oireachtas, considerable costs would be necessarily incurred and the goodwill and help of the
Government would have to be secured. Without these the public might reap all the fruits of the scheme and those who paid for
it get very little if any, benefit.
Without some such scheme as this, the value of the fishing rights of riparian owners is nil. With this scheme put through by the
unanimous action of the riparian owners the fishing rights become, if the scheme is successful, of some considerable value.
The benefit may, however be to the public rather than to those who have borne the cost, unless the Government stepped in and
made the necessary byelaws to prevent this, and the Government is not likely to legislate for a small number of private
individuals.
The alternative would appear to be that, the Government should take up the whole scheme and put the necessary bill through
the Oireachtas, taking over all fishing rights and making such byelaws as would appear to them to be necessary for their
protection.
……. We do not consider it likely that the Government would consider putting the scheme through for the benefit of a few
private owners. To put it through as a private scheme would be a costly business and without the Government there would be
great difficulty in securing that fish were not taken by some one who had not contributed.
We suggest that if the Government took over the whole scheme at cost and all the fishing rights and gave the riparian owners
first option of leasing the rights on their own section of the river, these owners would have the satisfaction of seeing the river
made of value to the country and, if they wanted fishing, of getting it at a fair price.
Letter to Dept. Fisheries from County Wicklow Anglers Association
23rd February 1935
This was unanimously adopted at meeting of Executive committee of above association:
............................ That we, the County Wicklow Anglers Association, being intensely interested in the improvement of the
fishing in the Wicklow River, desire to bring before the Government the fact that no fish can enter the Avonmore river because
of the poisoning from the Ochre mines at Avoca, and we respectfully suggest that the Government should take steps to prevent
this by adopting the scheme which has been proposed in connection with this contamination. In former years salmon used to
reach the spawning grounds in Loughs Dan and Tay and this is very desirable and the value to the country would be enormous
and would justify any expenditure that might be incurred.
Letter to Col. Bayly from J. Neill, Fisheries Office, Enniscorthy
19th February 1937
............................ I am holding over their report (Delap & Waller) of the discussion with Messrs Greene and Hassard for the
Board meeting in April when I shall return it. Should you require it sooner I shall return it. There seems to be a lot of difficulty
with the scheme, it seems doubtful if it will ever materialise unless the Dail makes some move in the matter.
15th April 1937
............................ I return the letter in connection with the Avoca River, the matter has been adjourned indefinitely by the Board.
Im afraid the scheme will not come off unless the Government does something.
Appendix 4.
Estimated and minimum densities (n/m2) of salmonids for all sites electrofished in the Avoca catchment 2002.
River Site Electrofishing Population Salmon 95% CL Salmon 95% CL Trout 95% CL 1+ & older 95% CL
Reference method estimation method fry (0+) parr (>0+) fry (0+) trout
Avonmore Am 1 handset Z 0.0 0.0 0.187 0.023 0.09 0.01
Am 2 handset S&L 0.013 md 0.001 0 0.171 0.089 0.075 0.002
Am 3 handset Z 0.009 0.0 0.062 md 0.022 md 0.14 0.03
Am 4 handset S&L 0 0 0.004 0 0.088 0.02
Am 5 handset Z 0.005 md 0.012 md 0.084 0.031 0.281 0.09
Am 6 handset S&L 0 0.009 0.007 0.084 0.006 0.107 0.018
Am 7 handset Z 0 0 0.028 md 0.27 0.02
Am 8 boat fishing p value (0.07) 0 0.009 0 0.003
Am 9 boat fishing p value (0.07) Present 0.032 Present 0.018
Am 10 boat fishing p value (0.07) Present 0.052 Present 0.076
Am 11 handset Z 0.09 0.02 0.07 0.02 0.03 0.000 0.035 md
Am 12 handset p value 0.031* 0.014** 0.16*** 0.1****
Am 13 boat fishing p value (0.07) 0 0.015 0 0.164
Am 14 boat fishing p value (0.07) Present 0.002 0 0.064
Am 15 boat fishing M-R Present 0.007 md Present 0.038 md
Avonbeg Ab 1 handset Z 0 0.006 md 0.046 md 0.09 0.01
Ab 2 handset S&L 0 0.001 0 0.008 md 0.14 0.05
Ab 3 handset Z 0.004 md 0.01 0 0.05 0.02 0.06 0
Ab 4 handset Z 0.48 0.09 0.14 0.01 0.064 md 0.09 0.02
Ab 5 handset Z 0.022 md 0.08 0.01 0.04 0.01 0.2 0.05
Aughrim Ag 1 handset S&L 0 0 0.03 0.000 0.26 0.02
Ag 2 boat fishing p value (0.37) 0 0 Present 1.06
Ag 3 boat fishing p value (0.37) 0 0 Present 0.687
Ag 4 boat fishing p value (0.37) 0 0 Present 0.934
Ag 5 handset S&L 0 0.004 0 0.13 0.03 0.21 0.01
Ag 6 handset S&L 0.005 0 0.2 0.02 0.62 md 0.19 0.03
Ag 7 handset S&L 0 0.009 0 0.097 md 0.17 0.06
Ag 8 boat fishing M-R 0 0.04 0 0 0.373 md
Ag 9 boat fishing M-R Present 0.009 0.003 Present 0.009 md
Ag 10 boat fishing M-R 0 0.030 0.009 Present 0.18 0.04
Ag 11 boat fishing M-R 0 0.014 0.005 Present 0.25 0.05
Ag 12 boat fishing p value (0.37) 0 0.003 Present 0.119
Ag 13 boat fishing p value (0.37) 0 0.004 Present 0.065
Ag 14 boat fishing p value (0.37) Present 0.064 Present 0.188
Ag 15 handset S&L 0 0.015 0 0.35 0.022 0.31 0.006
Ag 16 handset S&L 0 0.091 0.01 0.219 0.008 0.156 0.01
Ag 17 handset S&L 0.003 0.000 0.043 md 0.033 md 0.26 0.04
Ag 18 handset Z 0 0 Present Present
Ag 19 handset S&L 0 0 0.3 0.146 0.26 0.029
Ag 20 handset S&L 0.004 0 0.014 0 0.004 md 0.115 0.009
Ag 21 handset Z 0.04 0.010 0.09 0.03 0.009 md 0.11 0.01
Ag 22 boat fishing p value (0.37) Present 0.048 Present 0.048
Ag 23 boat fishing p value (0.37) Present 0.018 0 0.049
Ag 24 handset S&L 0 0 0.101 md 0.475 0.069
Ag 25 handset S&L 0.038 0.000 0.067 md 0.009 0.000 0.038 0
Ag 26 handset S&L 0.1 0.010 0.021 md 0.027 0.003 0.031 0.008
Ag 27 boat fishing p value (0.37) Present 0.002 Present 0.021
Ag 28 boat fishing p value (0.37) Present 0.002 0 0.024
Avoca Av 1 boat fishing M-R Present 0.002 md Present 0.0070 md
Av 2 handset Z 0.03 0.010 0.07 0 0.11 0.03 0.16 0.07
Av 3 boat fishing p value (0.07) Present 0.006 0.0 0.006
Av 4 boat fishing p value (0.07) Present 0.002 Present 0.048
Av 5 boat fishing p value (0.07) Present 0.004 0 0.0120
Av 9 handset S&L 0 0 0.008 0.000 0.17 0.07
Av 10 handset p value 0* 0** 0.032*** 0.1****
Av 11 handset S&L 0 0.006 0 0.13 0.007 0.15 0.02
Av 14 handset p value 0* 0.009** 0.087*** 0.4****
Av 6 boat fishing p value (0.07) 0 0 0 0
Av 7 boat fishing p value (0.07) 0 0 0 0
Av 8 handset S&L 0 0 0 0
Av 12 boat fishing p value (0.07) 0 0 0 0.006
Av 13 boat fishing p value (0.07) Present 0 0 0
NOTES
= Acid mine drainage affected channel.
S&L = Seber and LeCren’s (1967) method (2 fishings)
Z = Zippin’s (1957) method (3 fishings)
md = minimum density (no. fish captured/area fished)
M-R = Mark-recapture methodology applied
p-value = derived probability of capture value applied (value used shown in brackets in population estimation method column or marked by asterisk)
other p-values applied: * = 0.61 p-values (probability of capture in first fishing) were derived from Avoca electrofishing survey data.
** = 0.58 Mean values were calculated when the same methodologies/conditions applied. Mean values were applied
*** = 0.44 to fish nos. from sites where only 1 fishing was carried out. At most sites p values derived from trout boat
**** = 0.53 electrofishing had to be applied to salmon parr because salmon parr density data were limited.
p-value = derived probability of capture value applied (value used shown in brackets in population estimation method column or marked by asterisk)
other p-values applied: * = 0.61 p-values (probability of capture in first fishing) were derived from Avoca electrofishing survey data.
** = 0.58 Mean values were calculated when the same methodologies/conditions applied. Mean values were applied
*** = 0.44 to fish nos. from sites where only 1 fishing was carried out. At most sites p values derived from trout boat
**** = 0.53 electrofishing had to be applied to salmon parr because salmon parr density data were limited.
