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 14
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
Whites 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 OConnell 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; OSuilleabhain,
1996; Gallagher and OConnor, 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 8998% 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 OBrien; Dr Pat OConnor; Tony ONeill; Seoirce OToole;
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 & OConnor,
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 projects 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 peoples 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 1850s 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 (OReilly, 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 1860s, 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 promoters dream. Avoca Handweavers
The mill, established in 1723, is Irelands 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
Fitzgeralds 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 Europes 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 Irelands
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 1900s, 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 childrens 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 Councils 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 WCCs 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 Departments stated key roles and functions as they are germane
to this report:
Supporting the sustainable management, development and contribution
of Irelands 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 Nations 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 Wicklows 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 Irelands 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 Irelands
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 OSuilleabhain (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 years 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) + 72
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) + 14
O2(aq) + H+
(aq) Fe3+
(aq) + 12
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 Whites 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:
Lions Bridge: Upstream of the mine water discharges, on the Avonmore
River before it joins the Avonbeg River to create the Avoca River.
Whites 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 h