shannon international river basin district project
TRANSCRIPT
Funded by the Irish Government under the National Development Plan 2000-2006
SShhaannnnoonn IInntteerrnnaattiioonnaall RRiivveerr BBaassiinn DDiissttrriicctt PPrroojjeecctt
PPeeaattllaannddss RReeppoorrtt
July 2008
IBE5321/KF/DC081/Peatlands Report 2
Client Shannon RBD Project
Project Title Shannon RBD Project
Document Title Draft Peatlands Report
Document No. DC081
DCS TOC Text List of Tables List of Figures No. of Appendices This Document
Comprises 1 1 1 5 9 2
REVISION CONTROL TABLE Rev. Description of
Changes Prepared by
Checked by Approved by Date
0 Issued for internal review
KFAY Grace Glasgow 28/08/07
1 Issued for internal review
KFAY Grace Glasgow 30/08/07
2 Issued for internal review
KFAY Enda Thompson 04/10/07
3 Issued to BnM for review
KFAY Enda Thompson 12/11/07
4 Issued for internal review
KFAY Enda Thompson 13/12/07
5 Issued to BnM for review
KFAY Enda Thompson 14/12/07
6 Draft Issued to Enda Thompson
KFAY Enda Thompson 21/12/07
7 THunter Review KFAY Enda Thompson E Thompson 11/03/08 8 FINAL REPORT KFAY Enda Thompson E Thompson 30/07/08 The User is Responsible for Checking the Revision Status of this Document
IBE5321/KF/DC081/Peatlands Report 3
Table of Contents Page 1 Introduction
1.1 Water Framework Directive 4 1.2 The Shannon International River Basin District 4 1.3 Aim of peatlands study/objectives 6
2 Background
2.1 Development of raised bog 8 2.2 History of peat excavation industry 9 2.3 Bord na Móna peat excavation 9 2.4 Future uses of cutaway peatlands 11 2.5 Peatland Conservation 13
3 Potential Effects of Peat excavation activities on water quality & control
systems 3.1 Peat silt 16 3.2 Phosphorus 17 3.3 Bord na Móna environmental controls 18 3.4 EPA regulation of peat extraction activities 20 3.5 Bord na Móna Cutaway Bog Rehabilitation Plan 20 3.6 Findings of other studies 21
3.6.1 Direct phosphate release from bogs 3.6.2 Future climate change and water colour in Irish peatland
catchments 3.6.3 Lough Derg/Lough Ree catchment monitoring and
management project 4 Peatlands study monitoring
4.1 Bord na Móna data 22 4.2 Local authority monitoring data 23 4.3 Methodology – load estimation 25
5 Analysis of peatlands study results 5.1 Review of discharge monitoring data from peat silt lagoons 25 5.2 Nutrient and suspended solids loadings 28 5.3 Comparison of median MRP in various peatland catchments 29 5.4 Compliance with river Environmental Quality Standards 31
6 Conclusions 32 7 Management Recommendations 33 References 34
IBE5321/KF/DC081/Peatlands Report 4
Appendix I 35 Appendix II 40
1.0 INTRODUCTION
1.1 Water Framework Directive
The Water Framework Directive (WFD) came into force in 2000 and established a new,
strengthened system for the protection and improvement of water quality and water-
dependent ecosystems. It provides for coordinated water quality management based on
natural river basins (i.e. catchments). It aims at preventing any deterioration in the status
of any waters and at achieving at least “good status” for all waters by 2015. The status of
waters will be determined by chemical and ecological criteria for surface waters and
chemical and quantitative criteria for groundwaters. It requires the carrying out of
numerous preparatory tasks leading to the adoption by December 2009 of river basin
management plans and their implementation, review and updating on a six-year cycle.
Local authorities are working together and with other competent authorities to prepare a
River Basin Management Plan (RBMP) in relation to the Shannon River Basin District
(ShIRBD) by mid-2009.
1.2 The Shannon International River Basin District
The Shannon International River Basin District (ShIRBD) drains a land area of
approximately 18,000 km2 of which 2000 km2 is currently peatland, 22% (or 445 km2) of
which is owned by Bord na Móna. The map overleaf illustrates the ShIRBD area with
the locations of peatlands outlined.
Following the establishment of semi-state energy organisations such as Bord na Móna
and the Electricity Supply Board in the mid 1940’s, peatlands became a very important
resource within the Shannon catchment. The excavation of peat on a large scale has
resulted in large expanses of cutaway bog in the catchment. Peat excavation has the
potential to negatively impact on the water quality of rivers receiving drainage waters
unless proper mitigation measures are in place.
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1.3 Aim of Peatlands Study/Objectives
In compliance with the Water Framework Directive, characterisation of pressures and
their impacts was carried out for each river water body in the ShIRBD. This work was
carried out according to Article 5 of the directive and was published as the ShIRBD
Article 5 Characterisation Report. Summary results are presented below for those water
bodies in the ShIRBD containing Bord na Móna bogs in the Blackwater, Boora and
Mountdillon group of bogs.
The results of the Pressures and Impacts assessment in the WFD Article 5
Characterisation Report indicate that river water bodies in the peatlands are affected by
diffuse pollution. An assessment of the biological quality within these catchments by the
EPA indicate that if the status quo is maintained, these water bodies will fail to meet the
objectives of the Water Framework Directive by 2015. Although there is no link to a
specific pollution source, the excavation of peat is the predominant activity in these
catchments and would be expected to be the main pressure. Although Bord na Móna silt
ponds that are cleaned, managed and have a defined locatable outlet can technically be
described as point sources, these occur in areas with significant private peat production
that have unpiped unknown discharges. The combined pressure in certain areas can,
therefore, be best described as diffuse.
Table 1.1 Water Framework Directive Article 5 Results for Relevant River Water Bodies BnM
Peatland Group
No. Water Bodies
EPA Diffuse
Assessment
EPA Biological
Assessment
Morphology Assessment
Overall
Morphology Pressure Details
Mountdillon 10 3 x 1B 3 x 1A 1 x 1A 2 x 1B
Channelisation Intensive Land Use
Blackwater 8 5 x 1B 3 x 1A 1 x 1A 3 x 1B
Channelisation Intensive Land Use
Boora 7 1 x 1A 3 x 1B
3 X 1A 7 x 1B Channelisation
In addition to water quality issues, the peat extraction activities in these catchments may
produce morphological pressures due to intensification of land use and artificial
channelisation of natural streams and rivers. These water bodies are identified as part of
IBE5321/KF/DC081/Peatlands Report 7
a Further Characterisation study on Freshwater Morphology that is currently underway by
the ShIRBD Project.
The aims of this report are to provide the ShIRBD with an overview of
• different peatland types and activities,
• the impact of peat excavation on water quality
• future use of cutaway peatlands.
Peat excavation in the catchments studied is carried out at an industrial scale by Bord na
Móna and to a lesser scale by many private contractors. Most private peat excavation
activities tend to be relatively small scale and unlicensed. Consequently it is difficult to
obtain accurate information on these activities. However, monitoring data available
under Bord na Móna IPPC licenses and surface water quality monitoring carried out
by/on behalf of local authorities, allow for some assessment to be made of the effects of
peat excavation.
Specifically, this report:
• Reviews discharge data from peatlands, where available, from peatlands to
determine licence compliance and to assess silt lagoon performance;
• determines nutrient and suspended solids loadings to receiving waters using
available data;
• assesses Molybdate Reactive Phosphorus (MRP) data in receiving surface waters
in different Bord na Móna catchments to determine possible impacts from the
various land uses.
• provides a compliance check of the various Environmental Quality Standards set
under the Phosphorus Regulations and the Water Framework Directive.
A report on the significant water management issues (SWMI) within the ShIRBD was
published on 22nd June 2007. The report, known as the Water Matters report, is intended
to help engage the public and interested groups on the preparation of the River Basin
Management Plan. The Water Matters report is a preliminary overview of the main
IBE5321/KF/DC081/Peatlands Report 8
water-related issues and the actions suggested to address these issues. Peat excavation is
identified in the ShIRBD Water Matters report as being a locally significant water
management issue in terms of being an important landuse giving rise to potentially high
nutrient (particularly phosphorus) and suspended solids export into streams and rivers,
with subsequent effects on water quality. This study provides background information in
support of the ShIRBD Water Matters report published in June 2007.
2.0 BACKGROUND
The vast majority of peatlands in the ShIRBD are raised bog, which is typical of the
midlands of Ireland, but there are also portions of blanket bog and fen.
2.1 Development of a Raised Bog
At the end of the last Ice Age (over 10,000 years ago) water from melting ice
accumulated in river valleys and poorly-drained hollows, forming lakes where beds of
reeds developed. Over time the lakes gradually became infilled, developing into fens. At
this point, certain species of Sphagnum (mosses able to survive on rainwater which
contains few nutrients) began to colonise the fen. This was an important development
phase because, as this happens, the fen plants are gradually replaced by species which can
survive in the much poorer, acidic conditions, and a raised bog is subsequently formed.
Raised bogs are home to a wide variety of plant, animal and insect life, which have
adapted to and thrive in this sometimes harsh environment. Raised bogs are affected to
various degrees by human and mechanical modification throughout the RBD.
The majority of the raised bog in the RBD has been modified either through hand cutting,
machine excavation or milling. The main areas for raised peat excavation are the River
Suck catchment on the border of counties Galway and Roscommon and in the Midland
Counties of Offaly, Westmeath, Longford and parts of South Roscommon.
IBE5321/KF/DC081/Peatlands Report 9
2.2 History of peat excavation Industry
Large-scale mechanised peat excavation first took place in the Shannon catchment at
Turraun, Co Offaly using turf cutting machines powered by small locomotive engines.
About 8,000 tonnes of peat was excavated each year and transported out of the bog by
canal. In 1934, the Turf Development Board was established and in 1946 it became Bord
na Móna, and industrial peat excavation switched from sod peat to milled peat because of
lower operational costs. The first bogs developed by Bord na Móna in the Shannon
catchment were the Boora group of bogs in the River Brosna catchment and the
Mountdillion group in Co Longford. By the mid 1960’s over 15,000 hectares of
peatlands had been developed, 4,000 hectares at Lanesboro, 3,000 hectares at Blackwater
and 8,000 hectares at Boora. By the 1970’s Bord na Móna had increased production
significantly by developing new bogs near Shannonbridge and Lanesboro. This peat was
primarily used by the E.S.B. in electricity generation at Ferbane, Shannonbridge and
Lanesboro. In addition to Bord na Móna activities, peat is today also excavated for the
horticultural and domestic fuel markets.
2.3 Bord Na Móna peat excavation
It can take up to five years to bring a bog from an undrained state – (a virgin bog) to a
state where milled peat can be produced. Bogs are initially drained to reduce the water
content of the peat by installing a network of parallel open drains 15 m apart creating
strips of bog between two drains called a field. At this stage, shallow drains are opened
and the bog is allowed to drain further. As the surface of the bog gets firmer the drains
are gradually deepened until they are eventually about 1.5 m deep. After the bog has
been drained, it is levelled to slope towards the nearest drain. For milled peat production
the bog is laid out in a series of rectangular drying fields around 730 to 1830 m long and
14 m wide, with drains in between. There are essentially four operations in milled peat
production, milling, harrowing, ridging and harvesting.
2.3.1 Milling
Special milling machines work their way along the field. The miller itself consists of a
number of rotating drums fitted with pins to cut the peat. The rotating drums cut a thin
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layer of peat about 15mm deep. This layer of peat is called a crop. Typically the water
content of the crop is about 80%.
2.3.2 Harrowing
In the course of drying, the layer of peat is turned a few times to make the best use of
available drying. This is achieved with a machine called a harrow. The milled peat is left
to dry until its moisture content is down to between 40 and 50% which takes two or three
days in good weather.
2.3.3 Ridging
The dry milled peat is then scraped into long ridges running down the centres of each
field. This is done with a ridger, a machine consisting of a series of blades in the shape of
a V that opens the full width of the field.
2.3.4 Harvesting
Two production systems are used to stockpile peat: the Peco system, with every eleventh
field used to stockpile the peat from the five fields on either side; and the Haku System
with peat from each field transported in trailers to large central stockpiles.
The cycle of milling, harrowing, ridging and harvesting is repeated and in an average
year, 12 crops or production cycles are achieved. Eighty percent of the milled peat
produced by Bord na Móna is bought by the ESB as fuel for the generation of electricity.
The remaining milled peat is used to make briquettes.
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Harvesting of Peat Harrowing on a Bord na Móna bog .
2.4 Future Uses of Cutaway Peatlands
It is envisaged that by the year 2030 there will be about 20,000 hectares of exhausted
cutover bog in the ShIRBD. There are many different possible uses for the new land
which will be created by the stripping of the bogs. Most attention has been focused on
the development of new areas for forestry, agricultural activities and habitat re-creation.
There are also alternative management options for cutover bogs which are being
considered, and in many cases being tried out, by Bord na Móna.
2.4.1 Forestry
Large scale afforestation of the milled cutaway bogs of the midlands began in 1988 and
Bord na Móna have made available 2,400 hectares of cutaway midlands bog to Coillte.
The main tree species planted on the cutaway bogs is Sitka Spruce (Picea Sitchensis
(Bong.) Carr.), which comprises 76% of total plantings. Other species of importance
planted are Logepole Pine (Pinus Contorta Dougl. var contorta) (10%), Norway Spruce
(Picea abies (L.) Karst.) (2%) and Oak (Quercus spp.) (2%). The production of wood
IBE5321/KF/DC081/Peatlands Report 12
chips from trees may provide a significant part of the generating capacity of the ESB
power stations in the future.
2.4.2 Agriculture
There has been extensive research carried out into development of agriculture on cutover
bogs by both Bord na Móna and An Foras Taluntais (now Teagasc). The process for
grassland development from cutover bog involves initial levelling, perimeter drainage,
deep ploughing, timber removal, cultivation and grassing. In total, this takes up to three
years to complete. Over 100 hectares of grassland developed by Bord na Móna at Boora
and Derrygreenagh has been sold at agricultural land prices to local farmers.
2.4.3 Wetlands
The first bog to be fully excavated was Turraun in County Offaly. It consisted of about
250 acres of cutover bog underlain by lake clays and shell marls. A wide variety of
wildlife recolonised the site and, in 1991, the drains surrounding the area were closed off
and the site was allowed to flood to a depth of 1-1.5 metres. It has since become a haven
for wildlife - in particular for birds, with over 100 species recorded there. Other areas in
the Lough Boora Parklands have been left to recolonise naturally in the hope that
vegetation will establish itself and new peatlands will start to grow.
Bord na Móna are currently examining wetland creation as a land reclamation option for
when peat excavation finishes on these bogs by ceasing drainage of the bogs to allow
flooding to occur naturally. Lakes would then form in depressions and large wetland
areas would be created. In fact, Bord na Móna has successfully excavated a number of
small lakes in the Lough Boora Parklands, and in conjunction with both the Central
Fisheries Board and the Shannon Regional Fisheries Board some of these lakes have been
stocked with fish.
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Lough Boora Parklands, Cloghan Co. Offaly
2.5 Peatlands Conservation
With the demise of native woodlands in the 17th and 18th centuries, peat became the
major source of fuel in Ireland. Rights to cut peat on small plots of land, known as
turbary rights, were allocated to landowners. Ireland has no peatland conservation
strategy beyond a 50,000 ha acquisition target announced by the Government in 1987
(IPCC, 2005). Conflicts between turf cutting and conservation arise only where peat
excavation is occurring on sites that are of conservation or archaeological value
(NHAs/SACs/RMs). The National Parks and Wildlife Service is resolving the conflict
between the right of the individual to cut turf for domestic use and the need for wildlife
conservation on raised bog SACs via the 'Cessation of Turf Cutting Scheme'. This
scheme imposed a ban on the commercial and industrial cutting of peat on SACs in the
summer of 1999 (IPCC, 2005). Arrangements were made in the case of domestic cutters.
They were given ten years (until the end of the cutting season 2008) to make new
arrangements.
IBE5321/KF/DC081/Peatlands Report 14
However, peatlands in the Shannon Catchment have been targeted for conservation as
their value in terms of wildlife habitats and rarity on a world-wide scale is now being
realised. The EU and the international community have been involved in the preservation
of Irish peatlands through the Council of Europe’s recommendations to member states on
peatlands in Europe, the European Parliament’s “Resolution on the Protection of Irish
Bogs”, the International Mire Conservation Group and the Habitats’ Directive (Council
Directive, 92/43/EEC of 21 May, 1992). In Ireland the Irish Peatland Conservancy
Council (IPCC), which was established in 1982, is dedicated to preserving peatlands.
Private Turf Cutting in the catchment of the Little (Cloghan) River , Co. Offaly
IBE5321/KF/DC081/Peatlands Report 15
3.0 POTENTIAL EFFECTS OF PEAT EXCAVATION ACTIVITIES ON
WATER QUALITY & CONTROL SYSTEMS
The removal of large expanses of peatlands by mechanical excavation inevitably has a
major impact on the environment. Two key biological aspects of the peatland habitat are
adversely affected – the water balance and surface vegetation. The areas and extent of
drainage required for machine cutting can be very large. Drainage leads to the lowering
of the water table and, by exposing the upper layers to the air, results in the drying out of
the peat and alters the vegetation it supports. The channels left by machine cutting also
act as drains, further increasing water removal from the ecosystem.
In addition, large-scale unregulated peat excavation can have considerable effects on
water quality and is a potential contributor to eutrophication. Two water quality issues
associated with peat excavation are suspended solids and nutrient (e.g. Phosphorus)
release.
Bord na Móna peat harvesting from cutaway bog in Co. Offaly
IBE5321/KF/DC081/Peatlands Report 16
3.1 Peat Silt
Drainage of peatlands is an integral part of the peat milling operation and each worked
bog has a drain at 15 m intervals. These field drains feed into piped outfalls (usually 60
cm or 90 cm diameter pipes), and these take the water to silt lagoons prior to discharge
into the river Shannon system.
Bord na Móna drainage pattern on cutaway bog in Derrinlough, Co. Offaly
In terms of freshwater enrichment, peat is not considered a pollutant. However, being
basically solids suspended in water, it can be deposited at areas along watercourses and
cause the clouding of water where it is not treated. The main concern with peat silt
entering river systems is the impact it can have on aquatic life such as fish, particularly if
it settles in spawning areas.
High concentrations of peat silt in surface waters can kill fish by clogging up gills and or
making it impossible for the fish to feed. It can also clog up spawning gravels such that
spawning will not be possible and it also reduces primary productivity in rivers there by
affecting the quantities of fish food being produced. In addition, deposition of silt
IBE5321/KF/DC081/Peatlands Report 17
especially in gravels will also promote the development of extra rooted plant
productivity. This will give rise to the waterways being clogged, thus reducing the swim
area for fish and their ability to feed and thrive reducing stock density. In addition there
will also be a greater tendency for river drainage to occur which will have an extremely
destructive impact on the river and in particular its biology.
U.V. radiation from sunlight on silt deposits, contained in the shallow waters of the
rivers, causes the release of organically bound and bio available orthophosphate to the
waters. This will increase the amount of eutrophication in the water.
3.2 Phosphorus
Phosphorus is important in freshwater ecosystems since it is always the nutrient in
shortest supply controlling the rate of eutrophication. There is a strong statistical
relationship between the biological quality of rivers and MRP concentrations in Irish
rivers (McGarrigle et al 1992; Lucey et al, 1999). The empirical relationship suggests
that once annual median MRP values exceed 30 ugP/l, there is a strong statistical
likelihood that the river reach will have water quality issues (Clenaghan, 2003).
Phosphorus in the soil can be found in dissolved, colloidal or particulate forms. As
phosphorus has an affinity to bind to particulates, especially organic matter, wetland
areas such as bogs are generally considered as phosphorus sinks as they have the ability
to encourage siltation of suspended solids and hence retain the phosphorus. Generally,
considerable amounts of phosphorus are contained at the top layers of soil and it is
susceptible to being transported with the surface water runoff. Thus, peat bogs can also
be sources of nutrients as they can input phosphorus to water courses. Two forms are
usually found in the surface water runoff, the dissolved soluble phosphorus and the
phosphorus removed with sediments particularly the lighter and finer-sized particles such
as humic materials in peat.
Surface waters draining peat catchments are coloured due to the presence of high
concentrations of dissolved organic matter. Natural decomposition of peat releases
IBE5321/KF/DC081/Peatlands Report 18
dissolved organic matter into the surface waters. However, peat decomposition rates may
be altered by future climate change as modeled by Jennings et at 2006. Decomposition
rates may be accelerated by changes in temperature and soil moisture, while precipitation
will also drive the washout of organic matter, increasing the possibility of both higher
suspended solids and phosphorus concentrations being released to the aquatic
environment.
Dissolved humic materials (DHM’s) are naturally occurring biogenic chemicals which
can impart colour to water. In lakes, DHM may originate from peat bogs or other
wetlands in the lake catchment or they may come from the vegetation in the littoral areas
around the lake. Research has shown that DHM may absorb phosphate in the presence of
iron. Once DHM-iron phosphate complexes absorb phosphate they reduce its
bioavailability to algae (McGarrigle et al, 1992). It has also been shown that UV light in
sunlight can release the phosphorus bound to dissolved humic substances released from
bogs. Therefore, a combination of dissolved humic substances from bogs and natural
UV-sunlight could increase phosphate levels in freshwaters. Hence, the DHM in rivers
and lakes in the Shannon catchment is a potentially significant source of phosphorus. In
1992, McGarrigle at al., published an investigation into the effect of UV light on peaty or
humic waters in North Mayo and on the River Shannon at Lough Derg. This
investigation concluded that UV light does have an effect on phosphorus released from
Irish peaty waters.
3.3 Bord na Móna Environmental Controls
From a Bord Na Móna point of view, peat silt is milled peat that is lost to production
which should be retained from a commercial viewpoint. To counteract this loss and help
protect the aquatic environment, each Bord na Móna worked area of peatland drains into
a series of silt ponds or silt lagoons. At present, there are 235 silt settlement lagoon
systems with over 500 individual silt ponds throughout the Mountdillon, Blackwater and
Boora bog groups.
IBE5321/KF/DC081/Peatlands Report 19
These ponds, which contain settled peat silt until it can be removed, are rectangular 8 m
wide sumps sunk to a depth of 1.5 m below the invert of the drainage channel. A silt
pond works by slowing the water flow rate to allow suspended solids such as peat
particles to settle out. Each lagoon has its own pond maintenance programme that is
monitored regularly. The silt is cleaned out from the ponds twice a year, at the start of
the production seasons and before annual ditching operations. They must be cleaned
before production to cater for heavy rains when the production fields are peat covered.
Bord na Mona “VC 15” excavators machines have vastly improved cleaning operations
since they cause little turbulence. The pond outlets are blocked before cleaning
operations and the drainage water diverted through bypass channels and often through
adjacent parallel ponds.
An example of a Bord na Móna peat silt lagoon on Drinagh Bog, Co. Offaly
To monitor pond efficiency, silt sampling and analysis of the discharge are carried out.
An Emission Limit Value (ELV) of 35mg/l is set by the Environmental Protection
Agency as part of IPPC licensing regarding the levels of suspended solids allowed into
drainage waters. However, whereas Bord na Móna activities are regulated by the EPA,
private peat excavation is unlicensed and operates with little or no environmental control.
IBE5321/KF/DC081/Peatlands Report 20
3.4 EPA regulation of Bord na Móna peat excavation
Under Section 83(1) of the Environmental Protection agency Act, 1992, the excavation of
peat in the course of business which involves an area exceeding 50 hectares requires an
Integrated Pollution Prevention Control license from the EPA. Within the ShIRBD, Bord
na Móna Energy Ltd has three IPPC licenses covering all of its operations in the Shannon
catchment. These are the Boora Group Peatlands, the Blackwater Group Peatlands. Each
licence requires the licensee to monitor emissions to water for the following
determinants: pH; Flow; Suspended Solids; Total Solids; Total Phosphorus (as P);
Ammonium (as N); Colour and COD.
An Emission Limit Value (ELV) is set only for Suspended Solids at 35mg/l. At daily
monitoring locations the ELV applies to eight out of ten consecutive results, based on 24
hour flow proportional composite sampling. In addition, individual daily results shall not
exceed 1.5 times the ELV.
In terms of lagoons where grab sampling is undertaken, 75% of grab samples shall not
exceed the ELV and no sample is to exceed 3 times the ELV. Quarterly monitoring
frequency for suspended solids is stated in the license.
In addition, the activities at these locations are controlled and operated and emissions
take place as set out in their respective licenses. In addition to the various license
conditions set by the EPA, there is a stipulation requiring an Environmental Management
Programme to be in place with one of the objectives being to minimize the suspended
solid movement and improve discharges to surface water as stipulated in the licence.
This is known as cleaner production and is implemented by the adoption of good codes of
practice and standard operating procedures and training.
3.5 Bord na Móna Cutaway Bog Rehabilitation Plan
As required under Condition 10 of the IPPC license, Bord na Móna is required to prepare
a fully detailed plan for the permanent rehabilitation of the cutaway bogs within the
licensed areas. The primary aim of the rehabilitation programme for cutaway bogs is the
IBE5321/KF/DC081/Peatlands Report 21
development of sustainable after-uses of the bogs. Where possible, these uses will be of a
commercial nature, such as forestry and grassland. In other areas the appropriate after-use
will be the creation of wetland and/or wildlife habitats, which will enhance the national
biodiversity resource through the provision of habitat for flora and fauna. An example of
a cutaway rehabilitation plan for Bord na Móna is outlined in Appendix II of this report.
3.6 Findings of other studies
There have been various studies and reports published on the impact of peat and
phosphorus loadings in the Shannon system. This research included investigations into:
Direct phosphate release from bogs;
Future Climate Change and dissolved organic carbon production
Lough Derg/Lough Ree Catchment Monitoring and Management Project
3.6.1 Direct phosphate release from bogs
In the past routine effluent quality and quantity measurements from milled peat bogs
were not available and hence a number of researchers have tried to estimate the
phosphorus loads from Bord na Móna bogs by multiplying the annual average surface
runoff by means of annual phosphate concentration (McGarrigle et al., 1993). Based on
the results obtained in their study Bowman et al. 1993, estimated that the annual
phosphorus load from worked bogs in the Lough Derg catchment at 2.8 to 5.6 tonnes TP
was relatively low, contributing approximately 2% of the total phosphorus load to Lough
Derg from an area of worked bog of about 20,000 ha.
3.6.2 Future climate change and water quality in Irish peatland catchments
Jennings et al. 2006 used the EU CLIME project model calibrated for sites in Ireland to
simulate changes in dissolved organic carbon production and export from peatlands as a
result of climate change effects on decomposition rates. Projected changes in the climate
included an increase in air temperature in all seasons, increased precipitation in winter
and spring and decreased precipitation in the late summer and autumn. The model
indicated increases in stream flow in winter with decreases in the late summer and
autumn. The model also predicted a substantial future increase in dissolved organic
IBE5321/KF/DC081/Peatlands Report 22
carbon concentration. These increases would have important implications in water
quality in the catchments and for the ecology of the surface waters as peat decomposition
rates may change.
3.6.3 Lough Derg/Ree Catchment Monitoring and Management Project
The river water quality monitoring programme (April 1998 – March 1999) of the Lough
Derg and Lough Ree catchment monitoring and managements system quantified the
phosphorus loadings for catchments draining worked bog areas within the Brosna sub-
catchment. MRP loss was found to be 64 mg/m2/year from the Little (Cloghan) River.
The monitoring programme also identified that rivers whose drainage areas are
principally influenced by peat milling operations were characterised by elevated median
ammonium levels and occasionally individual high (>50 mg/l) suspended solids values.
In response to these preliminary findings a detailed peatlands monitoring programme was
established to further investigate export rates and receiving water quality.
4.0 PEATLANDS STUDY MONITORING
Within the ShIRBD, Bord na Móna carries out industrial-scale peat excavation at the
following group of bogs: Blackwater in Co. Offaly, Galway and Roscommon, Boora in
Co. Offaly and Mountdillon in Co. Longford and Roscommon. Three separate sets of
data were used to assess their impact on surface waters in the catchment:
• Bord na Móna IPPC compliance monitoring data of silt lagoon discharges from
the three different groups of bogs;
• Local Authority (ShIRBD lab) surface water monitoring under the Phosphorus
Regulations;
• Lough Derg/Lough Ree Catchment Management Project Data from surface water
monitoring in and around the Derrinlough Peat Briquette Factory.
IBE5321/KF/DC081/Peatlands Report 23
4.1 Bord na Móna Data
The data received from Bord na Móna were used to determine compliance with license
conditions, and to estimate suspended solids and phosphorus release from the various
peatlands. There are currently nine licensed discharges being monitored from bogs
within the Blackwater Group, nine within the Boora Group and eleven within the
Mountdillon Group. Each of these monitoring points is a discharge from a peat silt
lagoon.
Daily flow proportional monitoring for suspended solids and once-weekly flow
proportional monitoring for ammonium and Total Phosphorus is carried out at 1 site in
each Bog Group i.e. at SW68 in the Blackwater Group; SW18 in the Boora Group; and
SW76 in the Mountdillon Group. For all other licensed discharges, grab sampling is
carried out on a quarterly basis. Bord na Móna monitoring data for all sites was obtained
for the years 2004, 2005 and 2006.
4.2 Local Authority Monitoring Data
Local Authority monitoring data for the receiving surface waters were obtained through
the ShIRBD laboratory for the period 1998 – 2006. These data were used to determine
potential compliance with Environmental Quality Standards and thus, determine water
body status and compliance with the Water Framework Directive.
In addition, data compiled for the period 2000 – 2003 by the Lough Derg/Lough Ree
Catchment Management Project were included to provide a detailed account of the
nutrient loss from peatlands at their various stages of exploitation as outlined below:
(1) Clara Bog: Example of an intact lowland raised bog (2) Little (Cloghan) River: Example of a currently worked bog
(3) Tumduff Stream (Boora) Example of wetland and natural vegetation restoration.
A map overleaf outlines these three different peatland areas in Clara, Tumduff and
Cloghan Co. Offaly.
IBE5321/KF/DC081/Peatlands Report 24
IBE5321/KF/DC081/Peatlands Report 25
4.3 Methodology – Load Estimation
The daily, weekly and quarterly Bord na Móna monitoring data sets were used to
generate nutrient load. The method used was that developed by Webb et al. 2000.
Concentration data and discharge data at sampling time (or mean daily discharge on
sampling date), overall mean of the product of concentration and discharge for each
sampling time, multiplied by time factor k.
Total load = K (∑−
ns
i
ii
nsQC
1) Webb et al., 2000
K = conversion factor to take into account the period of record ns = number of samples Ci = instantaneous concentration
Qi = discharge at time of sampling rQ = mean discharge for the period of record
pQ = mean discharge for period between sampling Q = total discharge for period of record
ql
= mean load divided by mean discharge
ti, i =1,….,n = day number at which concentration is measured Annual loads were generated using the best estimate of the annual load calculated from
daily values, and is referred to as the ‘actual load’. Loads were calculated using the
product of concentration and flow for the days on which data was available.
5.0 ANALYSIS OF PEATLANDS STUDY RESULTS
The following analyses of the peatlands monitoring data were undertaken:
• A review of discharge monitoring data and silt lagoon performance.
• An assessment of nutrient and suspended solids loading from worked bogs.
• A comparison of median MRP in various peatland catchments.
• Water quality compliance checks against Environmental Quality Standards
5.1 Review of discharge monitoring data from peat silt lagoons
The review of the compliance monitoring data was carried out according to the relevant
IPPC licence conditions. Breeches of the suspended solids emission limit value are
permitted depending on the type of monitoring. Daily composite flow proportional
IBE5321/KF/DC081/Peatlands Report 26
samples are taken at three sites and the results of this monitoring is presented in Table
5.1a below. Grab samples are taken four times a year at 26 other sites and the results of
this monitoring is presented in Table 5.1b.
Table 5.1a. List of discharge non-compliances for suspended solids at the composite flow-
proportional sampling locations in the various groups of worked bog. Licence Condition
Boora (SW18) Non Compliance
Blackwater (SW68) Non Compliance
Mountdillon (SW76) Non Compliance
Eight out of ten
consecutive
daily samples
<35 mg/l
16, 17, 21 Jan 2004 21, 22, 23, 29, 30, 31 Oct 2004
6, 7 Dec 2004
14, 24, 25, 29 June 2005 13 Aug 2005 28 Aug 2005
27 March 2006
12 May 2006 08,09, 10, 11, 12, 13 Sept 2006
01 Nov 2006
20, 23 Jan 2004 17, 18 June 2004
04 Oct 2004 19, 20 Dec 2004
02, 06, 8, 9, 10, 11,12 Jan 2005
29 June 2005 06, 07, 08, 09, 10, 11, 12, 13 April 2005
30 Oct 2005 08, 30 Nov 2005
6 June 2006
16, 17, 18 Jan 2004 20, 21 Jan 2004
23 Mar 2005 7 June 2005 21 Oct 2005
Failures %Complaint Failures %Complaint Failures %Complaint 1.5 times the
ELV (52.5
mg/l)
2004 (9 times) 97% 2005 (6 times) 98% 2006 (10 times) 97%
2004 (7 times) 98% 2005 (11 times) 97% 2006 (1 time) 99%
2004 (5 times) 97% 2005 (3 times) 99% 2006 (0) 100%
The composite monitoring data indicates general compliance with licence conditions.
However, suspended solids non-compliances were recorded intermittently in the
discharge from SW18 (in the Boora group of bogs) during the reporting period 2004-
2006. Results for SW68 (in the Blackwater group of bogs) and SW76 (in the
Mountdillon group of bogs) indicate higher compliance and that the performance of the
silt lagoons have improved over previous years and are currently satisfactory, most
notably SW76.
Any discharge with suspended solids 1.5 times the ELV limit has the potential to
contribute greatly to the overall loading into the aquatic environment. Although the level
of compliance with this condition is high for SW68 and SW76 (99% and 100% compliant
respectively in 2006) the discharge from SW18 has a poor record.
Based on these results, silt lagoon SW18 is not as effective at removing peat particles
from surface water draining off the worked bog as the facilities at SW68 and SW76.
IBE5321/KF/DC081/Peatlands Report 27
Corrective action reports carried out by Bord na Móna for the EPA indicate that an
adjacent private turf operation in the same catchment is responsible for these non-
compliances. The impact of these breaches has been further considered by assessing
compliance in receiving waters.
Table 5.1b. List of discharge non-compliances for suspended solids at the grab sampling locations in the various groups of worked bog.
Licence Condition
Blackwater Group Non Compliance
Boora Group Non Compliance
Mountdillon Group Non Compliance
75% of samples <35 mg/l NONE NONE NONE
3 times the ELV (105 mg/l) 1 Sample
(Oct-Dec 2005)
NONE NONE
The grab sampling monitoring results for all sites demonstrate broad compliance with
licence conditions. Only one quarterly sample failed at SW22 in 2005. All previous and
subsequent monitoring at this site were well within the ELV for suspended solids.
On the basis on the results, these silt lagoons appear to be performing satisfactorily.
Examination of the data indicates a response to rainfall events in terms of the
concentration of suspended solids concentration in the discharge from the peat silt
lagoons. Monthly rainfall data from Bord na Móna at Blackwater in Co. Offaly was
compared against monthly average suspended solids concentration from a peat silt lagoon
in Blackwater (lagoon SW68). The graph below illustrates a general rise in suspended
solids concentration following periods of high rainfall, however other interventions such
as milling operations also influence silt response. Despite the apparent link of rainfall
and suspended solids concentration, the concentration of solids were in compliance with
the 35mg/l emission limit value.
IBE5321/KF/DC081/Peatlands Report 28
Plot of Monthly Average Rainfall and Monthly Average Suspended Solids Concentration for SW68
0
20
40
60
80
100
120
140
160
180
Jan-04Feb-04M
ar-04A
pr-04M
ay-04Jun-04Jul-04A
ug-04S
ep-04O
ct-04N
ov-04D
ec-04Jan-05Feb-05M
ar-05A
pr-05M
ay-05Jun-05Jul-05A
ug-05S
ep-05O
ct-05N
ov-05D
ec-05Jan-06Feb-06M
ar-06A
pr-06M
ay-06Jun-06Jul-06A
ug-06S
ep-06O
ct-06N
ov-06D
ec-06
Month
Ave
rage
Rai
nfa
0
5
10
15
20
25
30
35
40
Ave
rage
SS
Average RainfallAverage SS
5.2 Nutrient and Suspended Solids Loadings
The results of calculation of phosphorus loadings are presented in Appendix I. Table 5.2
summarises the results into totals for each of the three groups of bogs.
Table 5.2 Total Actual Annual Load of Total Phosphorus, Suspended Solids and
Ammonium for the Blackwater, Boora and Mountdillon group of bogs, calculated using Bord na Móna IPPC compliance monitoring data. .
Peatland Area Actual Annual
TP Loading kg/yr
Actual Annual SS Loading
kg/yr
Actual Annual NH4 Loading
kg/yr
Blackwater Group
429
190,220
11,082
Boora Group
873
120,869
12,107
Mountdillon Group
322
30,934
3,733
The recent data indicate that the current annual phosphorus loading from the worked bogs
in the Lough Derg catchment is in the order of 1.6 tonnes TP (although this is subject to
annual variation). Treatment of surface water from cutaways bogs via peat silt lagoons as
a practice commenced in the late 1990s. Bowman et al., 1993 estimated phosphorus load
IBE5321/KF/DC081/Peatlands Report 29
from worked bogs ranges from 2.8 to 5.6 tonnes TP, and the Lough Derg & Ree Project
(2001) indicated annual load estimates of circa 5.4 tonnes of TP. The data indicate that a
significant nutrient load reduction is most likely due to the installation of settlement
ponds as part of the IPPC licensing process.
Water samples taken at all monitoring sites in the Blackwater bogs for the October to
December 2005 quarter coincided with extreme surface water flows. High discharge
flows and concentrations of suspended solids from all lagoon discharges were recorded in
Blackwater bogs on this date. Although high levels were recorded during this period, the
concentrations were all in compliance with licence conditions where one quarterly sample
in a year is permitted to reach 105 mg/l.
5.3 Comparison of water quality in peatland catchments with different
land uses
Three separate catchments within the peatlands were monitored by Offaly County
Council as part of the Lough Derg/Lough Ree monitoring programme. The Little
(Cloghan) River has monitoring data available from 2000-2006 whereas the Clara Bog
and Tumduff catchments have data available from 2000-2003. There are different
peatland activities in each of the catchments and the monitoring data indicates a different
response to these activities or pressures, in terms of water quality. The catchments are
categorised in the following way:
(1) Clara Bog: Example of a non-harvested lowland raised bog (2) Little (Cloghan) River: Example of a currently worked bog (3) Tumduff Stream (Boora) Example of wetland and natural vegetation
restoration.
IBE5321/KF/DC081/Peatlands Report 30
Table 5.3. Comparison of water quality values from peatland catchments
Peatland Area Median
MPR mg/l Range
MPR mg/l Median
TP mg/l
Median Ammonium
mg/l
Median Suspended
Solids mg/l
Clara Bog
0.021
0.001 – 0.061
0.049
0.315
5.3
Little (Cloghan) River
0.020
0.004 – 0.697
0.048
0.547
8.0
Tumduff Stream (Boora)
0.004
0.001 – 0.013
0.020
0.561
5.3
Phosphorus monitoring data for the Tumduff stream (median MRP = 0.004 mg/l) indicate
MRP concentrations considerably lower than that at the other two sites. The catchment is
composed of reclaimed cutaway bog, mainly regenerated vegetation and wetlands, and
indicates that reclamation is successful at reducing water quality issues associated with
peatlands. However, the concentration of ammonium at this site was high (median
Ammonium = 0.561 mg/L).
While the median MRP concentrations at Clara Bog and the Little (Cloghan) River are
very similar, the range of results is much more varied and higher. The range in MRP
concentrations is higher for the Little (Cloghan) River indicating a higher loading of
phosphorus in this catchment. Clara Bog is a non-harvested lowland raised bog and MRP
data indicates runoff from the catchment has levels of phosphorus from natural decay of
organic peat. Although the concentration of ammonium at the Clara Bog site is lower
than those at the other two sites, the concentration is still very high (median ammonium =
0.315 mg/l).
IBE5321/KF/DC081/Peatlands Report 31
5.4 Compliance with Environmental Quality Standards (EQS) in
receiving waters
The Local Government (Water Pollution) Act, 1977 (Water Quality Standards for
Phosphorus) Regulations, 1998 prescribe a minimum satisfactory Molybdate-Reactive
Phosphate (MRP) median concentration target of ≤0.03 mgP/l (≤30 ugP/l) to be achieved
for rivers and a lower concentration for high status sites of ≤0.015 mgP/l (≤15 ugP/l for
Q5 sites). Examination of the median MRP values from each catchment indicates
compliance with this EQS.
However, individual sample results for the Little (Cloghan) River were well in excess of
this concentration as shown by the high range in concentration in Table 5.3 (Median
MRP range = 0.004 – 0.697 mgP/l). These individual high levels of MRP are most likely
associated with current peatland activity in the catchment.
Compliance with the various proposed EQS’s under the Water Framework Directive is
required for Molybdate-Reactive Phosphate (MPR) and for Ammonium (NH4+). The
proposed EQS to achieve the minimum WFD requirement of good status in Ireland is an
annual median of ≤0.05 mgP/l (50 ugP/l) for MRP and ≤0.06 mgNH4/l (60 ugNH4/l) for
Ammonium.
Each catchment is compliant with the proposed EQS for MRP under the WFD
classification system. Analysis of Ammonium data indicate that levels of ammonium in
the Little (Cloghan) River, Tumduff and Clara Bog Streams are far in excess of the EQS
of ≤0.06 ug NH4+/l for Ammonium. The results from the Clara Bog stream (drains an
area of non-harvested bog) may indicate that peatlands have naturally high levels of
Ammonium in surface water runoff. Non-harvested or virgin bog represents a large
portion of the peat lands in the Shannon catchment.
IBE5321/KF/DC081/Peatlands Report 32
6.0 CONCLUSIONS
• In general, the peat silt lagoons appear to be performing adequately. However,
there are occasional levels of suspended solids exceeding the emission limit
values. Isolated incidences of non-compliance can add considerable nutrient
loadings to the surface water system.
• Phosphorus load estimates indicate that the bogs in the Boora group discharge
greater loads of phosphorus into receiving waters with an estimated total actual
load of 872 kg TP/year- or 0.87 tonne TP year-1. The loading from the lagoons
range from 25 kg TP/year from SW42 to 245 kg TP/year from SW19.
• The concentration of Ammonium in the discharges from the peat silt lagoons are
generally high (e.g. 1.512 mg NH4/l from the Kilcamin lagoon) compared to
comparatively lower levels of phosphorus and suspended solids which settle in
the lagoons. However, peatland surface water runoff appears to have naturally
high Ammonium levels and this is evident in the receiving waters.
• Assessment of the monitoring data indicates that the EQS proposed under the
Water Framework Directive for MRP will be met in most of the peatland
catchments. However, the results indicate that the EQS for Ammonium is
unlikely to be achieved in catchments with actively worked peatlands. Again, this
must be attributed to naturally high Ammonium concentrations in peatland waters.
• In this study the determination of total actual loads of phosphorus from Bord na
Móna peatlands (1.6 tonnes TP per year) indicate lower phosphorus loading
compared with loads calculated by Bowman et al., in 1993 (2.8 to 5.6 tonnes TP)
and the Lough Derg & Ree Project in 2001 (circa 5.4 tonnes of TP). The data
indicates a significant nutrient load reduction most likely due to the installation of
settlement ponds as part of the IPPC licensing process.
• As seen in the Tumduff catchment, land use changes in excavated cutover bogs
can assist in improving water quality as observed by low concentrations and
loading of phosphorus and suspended solids.
IBE5321/KF/DC081/Peatlands Report 33
7.0 MANAGEMENT RECOMMENDATIONS
Certain recommendations can be made regarding the management of milled peat
operations, as it is clear that these activities affect water quality.
• Bord na Móna should continue its policy of treating surface water runoff from
cutaway bog though peat silt lagoons as the monitoring data indicate that they
significantly reduce the loadings of phosphorus and suspended solids entering
receiving waters.
• Compliance with Emission Limit Values set in the IPPC licenses for discharges
from Bord na Móna lagoons must continue to be achieved.
• The possibility of introducing emission limit values (ELV) for nutrients in Bord
na Móna IPPC licensed discharges should be examined by the EPA to take
account of the Environmental Quality Standards contained within the Surface
Water Classification Regulations. However, the natural background concentration
of phosphorus and ammonium arising from the decay of organic peat releasing
these nutrients into peatland waters would have to be taken into consideration
when setting the ELVs.
• Private peat producers with excavation of peat in areas >50 hectares should be
brought into the IPPC licensing system by the EPA.
• Discharges from smaller private enterprises, in catchments with less than good
water status, and with quantities of peat extraction less than the threshold
currently required for IPPC licensing should be licensed under the Water
Pollution Acts by the relevant Local Authority.
IBE5321/KF/DC081/Peatlands Report 34
References Bowman, JJ, mcGarrigle, ML., Clabby, KJ. 1993. Lough Derg: An Investigation of
Euthrophication and its causes. Part 1 Water Quality Assessment, Nutrient Sources,
Conclusions and Recommendations. A report to the Lough Derg Working Party.
Environmental Research Unit.
Lough Derg & Lough Ree Catchment Monitoring and Management System. 2001. Final
Report. Sponsored by the Department of the Environment and Local Government and
jointly administered by Clare County Council and Roscommon County Council.
Jennings, E., NicAonghusa, C., Allott, N., Naden, P., O’Hea, B., Pierson, D.,
Schneiderman, E. (2006). Future Climate Change and water colour in Irish peatland
catchments: results from the CLIME project.
McGarrigle, M.L., Champ, W.S.T., Larkin, P., Moore, M. 1993. The trophic status of
Lough Conn, An Investigation into the causes of recent accelerated eutrophication. Mayo
County Council.
IBE5321/KF/DC081/Peatlands Report 35
APPENDIX I
IBE5321/KF/DC081/Peatlands Report 36
Phosphorus Loadig from the Blackwater Group of Bogs Group Site Mean Median Min Max Actual Annual
Load (kg/y)
Blackwater SW3 0.180 0.063 0.002 1.207 66
SW13 0.241 0.088 0.006 0.883 88
SW17 0.052 0.031 0.009 0.226 19
SW22 0.129 0.045 0.003 0.796 47
SW63 0.098 0.044 0.010 0.640 15
SW89 0.173 0.055 0.003 1.047 63
SW95 0.191 0.024 0.006 1.687 70
SW118 0.102 0.035 0.015 0.403 37
SW68 0.066 0.034 0.005 0.508 24
TOTAL 429
Suspended Solids and Ammonium Loading from the Blackwater Group of Bogs Group Site Actual Annual
S.S. Load (kg/y)
Actual Annual Ammonium
Load (kg/y)
Blackwater SW3 49,604 2,702
SW13 28,105 1,773
SW17 3,008 360
SW22 42,569 978
SW63 16,094 1,162
SW89 13,968 1,759
SW95 13,382 569
SW118 13,167 515
SW68 10,323 1,265
TOTAL 190,220 11,083
IBE5321/KF/DC081/Peatlands Report 37
Phosphorus Loading from the Boora Group of Bogs Group Site Mean Median Min Max Actual Annual
Load (kg/y)
Boora SW42 0.069 0.072 0.011 0.122 25
SW19 0.670 0.563 0.007 2.694 245
SW17 0.287 0.150 0.016 0.824 105
SW32 0.168 0.189 0.006 0.286 61
SW51 0.081 0.084 0.005 0.151 30
SW10 0.300 0.168 0.010 0.855 110
SW28 0.159 0.122 0.024 0.408 58
SW31 0.182 0.085 0.044 0.632 66
SW18 0.476 0.350 0.011 5.547 173
TOTAL 872
Suspended Solids and Ammonium Loading from the Boora Group of Bogs Group Site Actual Annual
S.S. Load (kg/y)
Actual Annual Ammonium
Load (kg/y)
Boora SW42 2,889 601
SW19 32,446 3,501
SW17 2,360 585
SW32 8,183 336
SW51 3,694 1,049
SW10 10,244 1,628
SW28 13,151 1,570
SW31 7,647 924
SW18 40,255 1,914
TOTAL 120,869 12,108
Phosphorus Loading from the Mountdillon Group of Bogs
IBE5321/KF/DC081/Peatlands Report 38
Group Site Mean Median Min Max Actual Annual
Load (kg/y)
Mountdillon SW88 (DC1) 0.105 0.029 0.005 0.599 38
SW23 (GN4) 0.132 0.033 0.007 0.384 48
SW55 (BH64) 0.109 0.042 0.010 0.410 40
SW61 (CY70) 0.642 0.013 0.002 0.198 15
SW94 (DS3) 0.084 0.046 0.006 0.228 31
SW95 (LB3) 0.046 .028 0.012 0.136 17
SW6 0.037 0.012 0.006 0.099 14
SW39 nda nda nda nda nda
SW29 nda nda nda nda nda
SW34 nda nda nda nda nda
SW76 0.084 0.052 0.002 0.585 31
TOTAL 322*
nda = no data available (missing flow data). Calculation of Total Actual Annual Load determines average of data where no data is available.
Suspended Solids and Ammonium Loading from the Mountdillon Group of Bogs
Group Site Actual Annual S.S. Load
(kg/y)
Actual Annual Ammonium
Load (kg/y)
Mountdillon SW88 (DC1) 4,844 569
SW23 (GN4) 3,035 49
SW55 (BH64) 3,779 218
SW61 (CY70) 905 785
SW94 (DS3) 2,541 472
SW95 (LB3) 1,496 90
SW6 542 44
SW39 3,469 243
SW29 -
SW34 -
SW76 8,258 263
TOTAL 38,493 3,645
nda = no data available (missing flow data). Calculation of Total Actual Annual Load determines average of data where no data is available.
Group Site Total Annual
Load (TP) kg
Catchment
(m2)
Export Rate OP
(kg/m2/year)
Blackwater SW3 66 1300000 25
SW13 88 1940000 23
SW17 19 780000 12
SW22 47 450000 52
SW63 15 310000 24
SW89 63 810000 39
SW95 70 220000 158
SW118 37 580000 32
SW68 24 980000 12
Boora SW42 25 600000 21
SW19 245 3100000 39
SW17 105 1700000 31
SW32 61 1450000 21
SW51 30 700000 21
SW10 110 1550000 35
SW28 58 1000000 29
SW31 66 1600000 21
SW18 173 1600000 54
Mountdillon SW88 (DC1) 38 710000 27
SW23 (GN4) 48 500000 48
SW55 (BH64) 40 1300000 15
SW61 (CY70) 15 640000 12
SW94 (DS3) 31 400000 39
SW95 (LB3) 17 340000 25
SW6 14 1340000 5
SW39 Nda 1140000 -
SW29 Nda 550000 -
SW34 Nda 700000 -
SW76 31 3300000 5
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 40
APPENDIX II
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 41
Cutaway bog Rehabilitation: CONDITION 10 INTEGRATED POLLUTION
CONTROL LICENCE
MANAGEMENT GUIDELINES FOR THE PLANNING AND IMPLEMENTATION OF CUTAWAY BOG REHABILITATION IN ACCORDANCE WITH CONDITION 10 OF IPC LICENCES NOS.
500-507
BORD NA MÓNA JANUARY 2002
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 42
SUMMARY
Bord na Móna currently owns 80,000ha of land, which has been largely developed for
industrial peat production. In compliance with Integrated Pollution Control (IPC) licensing, a
rehabilitation plan must be prepared for all areas of bog where peat production has ceased, i.e.
cutaway bog. The primary aim of the rehabilitation programme for cutaway bog is the
development of sustainable after-uses. Where possible, these uses will be of a commercial
nature, such as forestry and grassland. In other areas the appropriate after-use will be the
creation of wetland and/or wildlife habitats, which will enhance the national biodiversity
resource through the provision of habitat for flora and fauna. A number of factors affect the
choice of potential after-use. Primary factors include peat depth and type, drainage, sub-
surface contours, subsoils and economics. Secondary factors include accessibility, adjacent
land-use, proximity to Natural Heritage Areas (NHAs) and Special Areas of Conservation
(SACs), archaeological interest and community imperatives. The triggers for development
and implementation of cutaway rehabilitation plans for each of the Bord na Móna Works are
outlined, as well as a decision tree that incorporates influencing factors to illustrate the
thought pathways that must be considered in establishing the best-suited after-use for any area
of cutaway bog. This document essentially serves as a guide to the after-use of Bord na Móna
owned industrial peat production sites in Ireland, based on the knowledge acquired to date.
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 43
TABLE OF CONTENTS
Summary 2 1. Introduction 4
1.1 Bord na Móna Compliance with Condition 10 of IPC Licensing 4
1.2 Consultation 5
1.3 Peatland types in Ireland 6
1.4 Industrial development of peatlands 10
2. Rehabilitation of cutaway bog 12
2.1 Cutaway bog – habitat conditions 12 2.2 Factors affecting after-use of cutaway bog 14
2.2.1 Primary factors 14
2.2.2 Other factors 20
2.3 After-use options 23 2.3.1 Grassland 23
2.3.2 Forestry 25
2.3.3 Wetlands 27
2.3.4 Other options 29
3. Cutaway bog rehabilitation plans 30
3.1 Triggers for development and implementation of a rehabilitation plan 30
3.2 Development of a rehabilitation plan 32
3.3 Determining the ‘best option’ after-use 33
4. General conclusions 35
5. References 36
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 44
1. INTRODUCTION
1.1 Bord na Móna Compliance with Condition 10 of IPC Licensing
Bord na Móna are required to provide rehabilitation plans for areas of cutaway bog under
Integrated Pollution Control (IPC) licensing. This will ultimately apply to most of the area
currently in ownership of Bord na Móna, which covers approximately 80,000ha of land. This
land is largely comprised of peatland - either production bog or un-developed bog, distributed
between discrete units of bog, which are in turn interspersed with agricultural areas. Bord na
Móna own in excess of 150 of these discrete units of bog, which range in size from 400ha up
to 5,000ha, and spread across the Irish midlands belt between the counties Kildare and
Galway, Roscommon and Tipperary. Each industrial peat production site (known as
individual Works in Bord na Móna, e.g. Blackwater Works and Boora Works), comprises a
complex of administration centres, peat production centres and workshops, travel paths,
railway lines, headlands, silt ponds, production bog and cutaway bog.
A number of potential after-uses for cutaway bog have been proposed by Bord na Móna,
including forestry, grassland and/or renaturation of the cutaway bogs for creation of wildlife
habitats. The potential after-uses depend on a number of aspects including physical and
economic factors, which are described in detail in this document. It is however, not possible
to state exactly what after-use will be applied to any particular cutaway bog area until the
condition of the post-industrial peat extraction site is assessed after completion of peat
extraction, i.e. peat depth and type remaining, accessibility, etc. This applies to the majority of
Bord na Móna holdings, therefore, despite the vast knowledge base that Bord na Móna has
acquired on potential after-uses of the cutaway bog (See References), only a general broad-
based plan can be outlined for all Bord na Móna Works at this point in time.
This document outlines rehabilitation work and after-uses implemented on Bord na Móna
cutaway bog to date. It is recognised that ultimately all areas of Bord na Móna bog will be
classified as cutaway bog and the same methodologies described here will be applied to all
Bord na Móna Works, with modifications, as the knowledge-base continues to grow.
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 45
This document aims to outline the following:
The main factors affecting potential after-uses of cutaway bog – physical, chemical,
economic and social.
A description of the characteristics of potential after-uses of the peat extraction sites that
have been considered to date.
An outline of the process whereby cutaway bog rehabilitation plans will be developed,
incorporating practical aspects, levels of decision making and consultation.
A decision tree that outlines the thought pathways that will be followed when considering
the most suitable after-use for a cutaway site, taking all influencing factors (both primary
and secondary) into consideration.
1.2 Consultation
Bord na Móna recognise that there will be a national interest in the after-use of extensive
areas of cutaway bog. Consultation with government departments and other agencies will be
conducted during the development of rehabilitation plans, both on a local and national level.
These organisations will include:
• Department of the Marine and Natural Resources (Forestry and Fisheries Boards)
• Department of Agriculture, Food and Rural Development
• Department of Arts, Heritage, Gaeltacht and The Islands (Dúchas - Parks and Wildlife;
Research, Bogs and Wetlands; Archaeological)
• Local Authorities
• Local communities
• Bord na Móna employees
• Teagasc
• The Heritage Council
• Non-governmental organisations
• National universities and colleges
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 46
1.3 Peatland Types in Ireland
Peatlands are specialised ecosystems, in which the rate of production exceeds the rate of
decomposition, resulting in the annual accumulation of peat and eventually in appropriate
conditions, to extensive and deep peat deposits. The factors that favour the development of
peatlands include impeded drainage, climate, hydrology, geomorphology, nutrient status and
glacial geology. Peatland development is promoted where permanently waterlogged
conditions prevail. This occurs where (a) precipitation exceeds evaporation, as is the case for
blanket bog habitats, or (b) where there is adequate rainfall, no distinct summer drying period
and impeded surface drainage, as in the development of raised bogs and fens.
Peatlands cover 17.2% of the area of the Republic of Ireland, of which Bord na Móna owns
approximately 7% of this figure. There are four types of peatland found in Ireland – fen,
raised bog, mountain blanket bog and Atlantic blanket bog. Bord na Móna produce peat
predominantly from raised bogs in the midlands, with one Works based on Atlantic blanket
bog in North-west Mayo (Oweninny Works). A brief outline is provided here of the
development of peatlands, peat types and the peat extraction methods employed by Bord na
Móna.
Peatland development in Ireland commenced after the last Ice Age, circa 10,000 years B.P.
(the following description of peatland development deals mainly with raised bogs, as this is
the most extensive peatland type in Bord na Móna ownership). As the glaciers retreated,
glacial till was deposited over the limestone of the midlands plain and the shale and sandstone
in the western regions. The resulting landscape was undulating, comprising scattered
depressions of varying depth and inter-linking high areas. Post-glaciation, fresh water lakes
formed in depressions. In many instances alluvial material was washed into these depressions,
resulting in the original glacial deposits being covered by 0m to 2m of alluvial material (silty
blue clay). In deeper depressions the alluvial material was overlain with shell marl. Marl is
70% to 90% carbonate in composition and contains the shells of gastropods and other
creatures that colonised these freshwater bodies. The areas between those fresh water lakes
remained uncovered and soil formation processes began. In time, these areas were colonised
by extensive forests.
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 47
Peat formation commenced in the sediment filled depressions (minerotrophic fens), gradually
spreading outside of the basins of origin and eventually covering the higher areas and
coalescing to form the extensive bog landscape that is typical of raised bogs and blanket bogs.
This gives the impression of a homogenous surface that belies the undulating glacial
topography underlying the peat, and it also highlights the origin of distinct fen peat types
(woody fen-peat formed on higher ground and Phragmites fen-peat largely formed in
depressions). This process of peatland development occurred slowly over a period of
thousands of years.
Fens are formed in areas where there is constant flushing of base-rich ground water. They are
described as minerotrophic (fed by ground water). Fen peats in Ireland have a relatively high
pH ranging from 4.5 to 8.0 (Doyle & Ó Críodáin 2002). Fen peats are mineral-rich with a
relatively high ash content (20%) and subject to a constant influx of nutrients in in-flowing
water. Fen vegetation is comprised mainly of sedges, with a diverse bryophyte layer and a
relatively rich herb component. Fens have been largely drained and cultivated for agricultural
use but there are some remaining examples in Ireland. Pollardstown Fen in Co. Kildare is the
best remaining example of a fen in Ireland. This fen was previously the only fen area in Bord
na Móna ownership and was handed over to the Irish State for conservation purposes in the
1970s. In the Irish midlands, fen peat development was generally superseded by raised bog
development. In extensive areas of cutaway bog, fen peat will be the main peat type
remaining after removal of the upper ombrotrophic peat layers in raised bogs developed by
Bord na Móna for fuel production.
Raised bogs are dome-shaped peat masses that once covered extensive areas in the Irish
midlands. Development of this bog type is dependent on the presence of Sphagnum species or
peatmosses. The vegetation is dominated by these bryophytes, which keep the peat surface
waterlogged as the peat moss grows above the water-table, while maintaining an acid
environment (typically less than pH 4) that favours continued Sphagnum establishment. The
peat is ombrotrophic (fed by precipitation only). The contrast between minerotrophic fen and
ombrotrophic peatland is extreme and the distinction rests primarily on the water regime. In
the successional development of raised bogs, the transition from fen to ombrotrophic peat
occurs once the vegetation is elevated above the influence of base-rich waters, and the
vegetation is solely supplied by nutrient-poor water derived from the atmosphere. The depth
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 48
of ombrotrophic or Sphagnum peat varies between bogs. Generally the basal layers comprise
lake-mud and fen peats. This shallow fen peat layer (generally 1m to 2m) is over lain with
highly humified Sphagnum peat, which is in turn over lain with poorly humified Sphagnum-
peat (Fig. 1). Total peat depth in any raised bog can be up to 15m in an un-drained state.
Within the upper peat layer, an active surface layer has been identified and is known as the
acrotelm. The acrotelm is generally 0.5m deep and forms the main water conduit in the bog. It
is in this active layer that physical and chemical processes occur. The underlying layer is
referred to as the catotelm and comprises the remaining inactive deep peat deposits. There are
no chemical processes ongoing in this layer and water movement is particularly slow. In
development of raised bogs for peat production, the acrotelm is destroyed and most of the
catotelm is removed. Once the acrotelm is destroyed, there is little possibility of restoring a
raised bog to its previous condition.
Blanket bogs have developed in Ireland in areas of high rainfall, covering entire landscapes.
Mountain blanket bogs have formed across mountain plateaux and gentle slopes (usually up
to 15º, but on slopes of up to 25º in the extreme south-west in mountainous areas of counties
Sphagnum peat (slightly humified)
Sphagnum peat (highly humified)
Fen peat
Glacial deposit
5Km
8m
Fig. 1 Outline of raised bog development (after Mitchell 1986; N.B. not to scale). The lower blue layer comprises lake-mud that overlies glacial deposit. The upper slightly humified peat layer is utilised for horticultural peat while the lower highly humified layers are utilised for energy production.
Woody fen peat
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 49
Cork and Kerry) (Doyle & Ó Críodáin 2002). Atlantic blanket bog has developed on lowland
areas, occurring at altitudes below 200m. Rainfall in these areas exceeds evaporation and
leads to the development of permanently waterlogged soils, and hence conditions that favour
the development of peat.
Bord na Móna developed two peat extraction sites on Atlantic blanket bog in the west of
Ireland, at Bellacorick and Bangor Erris in North-west Mayo. The peat in Atlantic blanket bog
systems is generally shallower (average depth 4m) and the underlying topography is
comprised of a series of gravel hills and ridges. In the case of the cutaway Atlantic blanket
bogs, the remaining shallow peat (usually less than 0.5m) is ombrotrophic with occasional
pockets of relatively deep minerotrophic peat (more than 1m). This is a consequence of the
bog developing over acidic glacial till as opposed to forming in calcareous influenced lake
basins as is the case for raised bogs.
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 50
1.4 Industrial Development of Peatlands
Peat is a highly organic soil type consisting of partially decomposed remains of plants and
animals. Its exploitative value for fuel been recognised for centuries, but mechanisation of the
process in the last sixty years has allowed extensive areas of peat to be exploited more
efficiently and economically. Bord na Móna was established in 1946 to promote production
and marketing of peat products.
THE BORD NA MÓNA EXTRACTION POLICY FAVOURS HARVESTING OF AS MUCH PEAT AS IS POSSIBLE, UNTIL (A) THE UNDERLYING SUBSTRATE IS REACHED, (B) A LAYER OF BOG TIMBER IS ENCOUNTERED, OR (C) CONTINUED DRAINAGE IS NO LONGER FEASIBLE. THE PEAT EXTRACTION METHODS EMPLOYED BY BORD NA MÓNA ALLOW FOR EFFICIENT EXTRACTION OF PEAT. SUBSEQUENTLY, THE PEAT COVER REMAINING IN AN INDUSTRIAL CUTAWAY BOG CAN VARY FROM A FEW MILLIMETRES TO A FEW METRES. THIS VARIATION REFLECTS THE DEGREE OF UNDULATION OF SUB-SURFACE CONTOURS. THE VARIABILITY OF SUB-SURFACE CONTOURS IS ONE OF THE PRIMARY FACTORS AFFECTING THE CHOICE OF AFTER-USE OF CUTAWAY BOG (SEE 2.2.1).
The different layers of peat have very different physical properties and this in turn relates to
their potential commercial use. The preferred peat for horticultural purposes is the upper,
poorly humified Sphagnum-peat layer, and this is related to the high water retention properties
of the peat. In Irish raised bogs this peat is generally confined to the upper 2m to 3m of peat.
The lower, highly humified peat is suitable for fuel production. Where bogs are utilised only
for horticultural peat, the remaining bog is referred to as cut-over bog to reflect the relatively
deep layers of ombrotrophic peat. If the remaining peat however, is targeted for fuel
production, peat will continue to be harvested until the ash content of the peat exceeds
accepted levels, or until it is not economically viable to do so. This results in a broad range of
cutaway habitats that are outlined in the next section (See 2.1).
Before peat can be harvested a series of steps must be taken to drain the bog and develop the site for operation of Bord na Móna machinery.
The surface of the bog is prepared for peat extraction by drainage and stripping of the surface vegetation. Drains are inserted at 15m
intervals, giving rise to a network of long, parallel peat fields. Within three years the surface vegetation is removed and the bog is sufficiently
dry for peat extraction to commence.
Peat harvesting is generally between the months of May and September, when drying conditions are optimal. The main methods of peat
extraction are milling and sod peat cutting, but currently milling is the most widespread method. The milling method involves the use of
machinery that scarifies and loosens a thin layer of peat (15mm to 20mm) on the surface of the peat fields. This loosened peat is
subsequently turned to facilitate solar drying to attain moisture content of 45% to 50%. The peat is then stored in stockpiles adjacent to the
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 51
production fields until required. Milling may continue for up to forty to fifty years on any peat field, depending on peat depth and market
demand. The peat surface is lowered by 1m over a ten-year period. The annual rate of peat removal is variable, and this is a consequence of
shortened (and occasionally prolonged) harvest seasons due to climatic variability.
The peat extraction infrastructure comprises a narrow gauge railway network used predominantly for transporting peat from stockpiles to the
final destination, e.g. an electricity generating station. An extensive railway network has proven successful for transport across the peat
production areas and development and maintenance of a road network was considered unpractical. All other travel on the bog is generally
along peat fields and/or headlands, employing the use of low bearing pressure machinery that is suitable for bog conditions.
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 52
2. Rehabilitation of cutaway bog
2.1 Cutaway Bog – Habitat Conditions
Cutaway bog can be loosely defined as former production bog. This can range from a single
cutaway (former production) field that is surrounded by active peat production fields, to an
entire former production area comprising several peat fields, extensive drainage network,
railway beds and intact bog remnants. Cutaway bog is therefore, a broad term under which a
number of conditions and/or habitats are included.
When production ceases, cutaway bog can be broken down into one of (or a number of)
habitat types (conditions) as follows:
1. Intact bog remnants – areas of bog that vary in size from less than 1ha up to extensive
areas, usually bordering production bog but may comprise separate entities, which were
never fully developed for peat extraction.
2. Deep ombrotrophic peat – more than two metres of peat, typically acidic (e.g. horticultural
cut-over peat).
3. Shallow ombrotrophic peat – less than 2 metres of peat, also acidic (e.g. Atlantic blanket
bog cutaway).
4. Shallow minerotrophic (fen) peat – usually less than 2m peat, typically influenced by
calcareous groundwater (e.g. energy-peat cutaway).
5. Shell marl – basal calcium-rich deposit underlying fen peat (former lake deposits).
6. Mineral soil – comprised of glacial tills and gravel, generally acidic in western regions
and alkaline in the midlands region of Ireland.
Therefore, conditions within any production – cutaway bog can be variable, often with each
habitat type represented. This highlights the need for a comprehensive baseline study of each
cutaway bog unit to be carried out before a suitable after-use can be applied. There may be
more than one after-use applicable within any cutaway bog.
The primary aim of the rehabilitation programme for cutaway bog is the development of
sustainable after-uses. Where possible, these uses will be of a commercial nature, such as
forestry (both hardwood and coniferous) and grassland. In other areas the appropriate after-
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 53
use will be the creation of wetland and/or wildlife habitats, which will enhance the national
biodiversity resource through the provision of habitat for flora and fauna. A number of
research projects were conducted to examine these after-uses reflecting the current trend in
other countries (Grosvenier et al. 1995, 2000; Money, 1995 a, b; Price 1998; Quinty &
Rochefort 1997, 2000; Rochefort & Campeau 1997; Sliva 2000; Wheeler & Shaw 1995;
Wheeler et al. 1998; 2000). Commercial after-uses include development of grassland, forestry
and creation of angling lakes (Boyle et al. 1998; Caffrey 1998; Egan 1995, 1998a, b; Jones &
Farrell 2000; McNally 1984). Non-commercial after-uses include the development of wetland
areas and wildlife areas (Egan 1995; Farrell 2001; Farrell & Doyle 1998, 2002; Feehan &
Kaye 1998; Feehan & O’Donovan 1996; Kavanagh 1991, 1996, 1998; Leader 1999;
O’Connor 2000; O’Connor & Reynolds 2000; Rowlands 2001; Rowlands & Feehan 2000 a,
b; Trodd & Murray 2000). Where there are intact bog remnants, these areas will be preserved
and where possible they will be managed to conserve and/or restore peat-forming conditions.
We are therefore presented with cutaway bog complexes that comprise a diversity of habitat
conditions, which may lead to the eventual establishment of a mosaic of after-uses that will
ultimately form a diverse landscape in place of the industrial peat production landscape that
currently exists.
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 54
2.2 Factors Affecting After-use of Cutaway Bog
2.2.1 Primary factors
A number of factors affect the choice of after-use option for cutaway bog. While a proposal
for after-use of total Bord na Móna cutaway bog areas has been outlined (Table 1), this serves
only as a guide, as the after-use will be largely dictated by the physical and chemical
characteristics presented by any cutaway bog. The main factors affecting after-use selection
are peat type, peat depth, drainage, sub-surface contours and subsoil type. While each primary
factor is discussed under a separate heading, the discussion for each overlaps in some places
highlighting how closely inter-related each factor is, e.g. peat type and sub-surface contours,
drainage and peat depth, etc. The secondary factors that may be primary factors in some
situations are accessibility, community imperatives, adjacent land-use, proximity to NHAs
and SACs and presence and/or absence of objects of archaeological interest.
Policy and economics
Bord na Móna cutaway bog policy will be that where an economically viable after-use can
be established on cutaway bog, that will be the most favourable option. This will not result
in a loss of potential wildlife habitats as it has been shown that more than 25% of the
cutaway will be unsuitable for any economic after-use. As well as that, consideration will
be given where cutaway bog is located adjacent to SACs and NHAs, and where there may
be potentially damaging effects to the local biodiversity resource. McNally (1997) outlines
the breakdown for proposed uses of cutaway bog (Table 1).
Table 1. Post-industrial future of Bord na Móna cutaway bog
Potential use Percent of BNM
holdings
Coniferous plantation
forestry
Wetland rehabilitation
40%-50%
20%-30%
20%-30%
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 55
Agricultural grassland
Hardwood forestry
10%-20%
A number of factors will alter these proposed figures, as research is ongoing and market
demands for forestry and/or grassland fluctuates. Nonetheless, research and development
into these after-uses is ongoing and the techniques involved are being continually refined.
Other after-uses such as wind-farms, gravel pits, etc. are also being explored, but these
options are generally small-scale and/or once-off operations where site-specific conditions
are suitable, e.g. the wind-farm at Bellacorick.
Cost of after-use will be a major factor of consideration for Bord na Móna in the post-
industrial development of cutaway bog. While a number of after-uses have been proposed
for cutaway bog, the market available and the cost of establishing, for example grassland,
even if conditions are suitable, will play a major role in deciding whether or not that will
be the chosen after-use. The economic viability of any commercial venture will be a
product of all of the factors outlined below, particularly factors such as accessibility, local
demand, national demand and cost of materials and/or labour.
The cost of any commercial venture is expected to largely exceed the cost associated with
renaturation and establishment of wildlife habitat, so where there is no commercial venture
practicable for a cutaway area, it will automatically be targeted for wetland development
and/or replacement wildlife habitats. Therefore, on-site conditions and economic
considerations ultimately control Bord na Móna policy for the after-use of cutaway bog.
Peat-type and depth
Peat depth and type are fundamental to the selection of after-uses for cutaway bog. Both
factors are inter-related, and are in turn a function of original peat depth, undulation of the
bog floor and the degree to which peat extraction was conducted.
Midland raised bogs consist of two distinct peat types, with a number of sub-types within
each category. The most abundant peat type is the ombrotrophic Sphagnum peat type (2m
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 56
to 10m deep) that is largely utilised for horticultural peat (the upper poorly humified layer)
and energy production (the lower highly humified layer). The basal peat layers are
minerotrophic and comprise a number of types that are a consequence of origin within
raised bog development, and in turn related to the sub-surface contours (See 1.3). Fen peat
can be broken into two sub-types, namely Phragmites fen-peat and woody fen-peat The
Phragmites and woody fen peat types each have specific characteristics that influence their
suitability for after-uses. In general, Phragmites-peat requires a higher level of treatment
for development of grassland and forestry than woody fen-peat. Fen peat will be the most
extensive peat type remaining in cutaway bog areas, although there will be ombrotrophic
peat where peat deposits are not utilised completely.
Peat depth can be a critical factor in determining the after-use of any cutaway bog. An
attempt is made here to define certain critical peat depths, however, this delimitation can
be affected by site-specific characteristics.
• Deep ombrotrophic peat, typically more than 2m – There are two situations where deep
ombrotrophic peat may be encountered: (i) Deep peat that has a vegetation cover - this
applies to bog remnants that usually form a fringe around a developed peat production
bog. These bog remnants generally have a relatively intact vegetation cover comprising
typical peatland plants and are therefore, considered stable habitats. These areas will
not require any active rehabilitation work. (ii) Deep peat remaining after peat
production (compressed peat, bare field surface), which is ombrotrophic in nature. To
date, there has been no economic after-use developed for deep ombrotrophic peat. This
is a consequence of drainage difficulties, acidity and nutrient requirements. The most
appropriate after-use for these deep peat areas is considered to be the establishment of
wildlife habitat areas. These areas become colonised by Calluna vulgaris and
Eriophorum angustifolium, largely developing heathland vegetation and in wetter
areas, embryonic peat-forming communities re-establish. The peat is stabilised and the
after-use is considered sustainable with minimal maintenance required. Deep peat
deposits remaining after peat extraction ceases are generally termed cut-over, as the
peat resource hasn’t been exhausted completely. This is in contrast to the term cutaway
that generally refers to an area where the peat depth does not exceed 2m.
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 57
• Shallow minerotrophic peat, 1m to 2m deep – Provided drainage of the cutaway bog is
good, shallow minerotrophic peat areas will be designated for coniferous forestry.
Research has shown that deep peats are unsuitable for forestry and while forestry can
be successfully established on peat depths less than 1m, the current policy (State Forest
Service) is that trees will not be planted on peat depths less than 0.5m. A range of
hardwood species can be established on all peat depths (0m to 2m), and research is
ongoing in this area to determine the optimal conditions for commercial growing of
hardwood tress on cutaway bog (Jones & Farrell 2000).
• Peat depths 0m to 1m – Bord na Móna research has shown than on peat depths up to
1m that are underlain with suitable soils and with good drainage conditions,
agricultural grassland can be successfully established. Where drainage is poor however,
and/or the area is frequently inundated with floodwaters, the cutaway bog will be
allowed to revegetate naturally with typical fen vegetation. Fen establishment has
occurred successfully on a number of shallow, minerotrophic cutaway bog areas, e.g.
Turraun. Where there is no peat remaining, the underlying marl and/or glacial till will
be revealed. These areas are generally interspersed with areas of shallow peat, and will
either be incorporated into grassland areas or naturally revegetated fen areas.
In summary, shallow minerotrophic peats are more suitable for commercial after-uses
than deep ombrotrophic peats (Table 2), while essentially all cutaway bog areas could be
managed for non-commercial after-uses (wetlands and/or wildlife habitat). The former
will be a consequence of peat extraction for energy peat where all layers of peat are
removed (and also the most extensive scenario that will be encountered), while the latter
is generally a consequence of horticultural peat extraction.
Table 2. Critical peat depths for potential after-uses of cutaway bog.
Grassland Forestry Wetlands/wildlife
habitat Peat depth Shallow (1m –2m) * * Shallow (0m-1m) * * Deep (>2m) * Peat type Minerotrophic * * * Ombrotrophic *
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 58
There is one exception to the above delimitation of peat depths, and that is the cutaway Atlantic blanket bog situation. Because of the nature of development of the bog, all peats are ombrotrophic – both shallow and deep, and therefore there is no economic after-use suitable for the Oweninny Works. The proposed after-use is therefore re-establishment of replacement wetland plant communities that will allow the area to blend in with the surrounding Atlantic blanket bog landscape.
Drainage
The peat production drainage network is the most important factor for efficient peat extraction. Therefore, until peat extraction is completely finished within a peat production unit, it is not possible to close drains to encourage revegetation. When peat production is completed in an area of bog, the field drains and main out-falls are typically left open and will remain as such where commercial after-uses such as forestry and grassland are selected.
While all raised bogs are drained by gravity in initial years, as peat extraction continues and the level of the peat is lowered, in some cases the peat production fields are lower than the level of the regional arterial drainage network. It then becomes necessary to install artificial pumps for peat extraction to continue. Such is the case for production bogs along the River Shannon in West Offaly – these bogs are continually pumped to allow peat production to continue. Once the pumps are turned off, the area will be flooded. The only after-use available for these pumped areas is therefore renaturation of the site and establishment of wetland habitats (Leader 1999). Where the drainage is good, usually where the regional water-table lies below the peat surface, there is an improved opportunity for development of the site for commercial operations. Therefore, drainage of the cutaway bog and drainage of the surrounding land are inter-related, while also a product of peat depth and sub-surface contours.
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 59
Ultimately, if cutaway bog is difficult to drain, the cost of maintaining or improving
drainage outweighs the benefits of developing the area for commercial forestry and
grassland. These areas will be allowed to revert to wildlife habitat areas, as has been
shown to occur successfully on a number of cutaway bog areas. Converse to that
scenario, in some places drainage of surrounding private agricultural land is
dependent on the maintenance of an intact drainage infrastructure through the
adjacent Bord na Móna industrial peat production area. In such cases, Bord na
Móna may be required to maintain the integrity of the drainage network of former
production areas.
Sub-surface contours
Even though conventional diagrams of raised bog development show a typically
uniform sub-surface, the landscape underlying bogs in general is not uniform. Sub-
surface contours vary greatly from bog to bog. In any raised bog, the floor contours
may vary within a couple of metres or may vary over extensive areas – this is a
consequence of glacial deposition that is not uniform. As industrial peat extraction
continues from a drained raised bog, occasionally gravel hills and/or depressions in
an otherwise level peat field are encountered. If these features are abundant within
a production bog they lead to difficulties for peat extraction and drainage. Where
the sub-surface contours are undulating, pockets of peat may be relatively deep and
difficult to drain, leading to difficulties in developing a site for grassland and/or
forestry.
Subsoil type
The underlying subsoil type of any bog largely determines the chemical nature of
the basal layers of peat. Limestone underlies the central plain of Ireland and this is
generally overlain with glacial deposits. Calcareous waters therefore, largely
influence the mineral soil underlying the midlands raised bogs. Carboniferous
shales underlie the glacial deposits beneath Atlantic blanket bog and there is
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 60
therefore, no large-scale calcareous influence. There are however, occasional
calcium and iron-rich up-wellings across the Bellacorick cutaway, but the subsoil is
largely acidic. The economic viability of grassland and/or afforestation is largely
reduced where the underlying subsoil is acidic, the cost of increasing nutrient status
generally outweighing any economic benefits. Subsoil type is strongly related to the
sub-surface contours, particularly in relation to post-glacial events (See Peat depth
and type).
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 61
2.2.2 Other factors
A number of secondary factors will also be taken into consideration on selection of
appropriate after-uses for cutaway bog. Each of these factors may be applicable in one or
more sites and in some cases may be over-riding features.
Accessibility
Accessibility is a product of location and proximity to established settlement areas,
and is important for all potential after-uses in relation to access for machinery, public
access for amenity purposes and/or access for maintenance work. Access may be by
railway line only, or old railway beds (there is no road network established in any
Works). In extensive bog areas, conditions can be difficult for travel, particularly
during winter months with rehabilitation work therefore, largely restricted to drier
months. To improve access, a road network would have to be established and this
would be dependent on a proximal source of material for development of such a
network. A consideration relevant for establishment of wind-farm and other alternative
energy options, would in turn be access to a main electricity gridline. Accessibility is
also inter-related with adjacent land-use.
Adjacent land-use
While there are currently restrictions on agricultural output within the European
Union, there are still opportunities for farming under less intensive conditions. This
would provide an outlet for new land coming on stream for farmers. Conversely, if a
cutaway bog area is in a poorly developed region there may be little call for ‘green
land’. Nevertheless, there may be a requirement for local employment opportunities
and forestry may be the option as long as the area is easy accessed. Consultation with
local landowners would be required to determine what the needs of the local area are.
Adjacent land-use would also have to account for the proximity of NHAs and SACs
and/or local community interests.
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 62
Proximity of NHAs and SACs
If an area of cutaway bog lies between NHA and SAC areas, then the ‘best’ option would be to rehabilitate the cutaway bog to provide a wildlife corridor between such areas. This is particularly relevant where Red Data species present could benefit from an expansion of the local habitat available. An example of this is the case of the grey partridge, a rare bird species whose breeding population in Ireland is confined to an area of cutaway bog within the Boora Parklands area (Kavanagh 1991). Also, development of cutaway bogs adjacent to SAC areas (for example for forestry or grassland), may have a negative impact on the integrity of the protected area and would therefore not be a suitable practice. If the protected area had been compromised by peat production developments, the adjacent area of cutaway bog could be rehabilitated to enhance the habitat and wildlife value. In the case of a raised bog, a number of options are available such as rewetting the lagg zone, extending SAC area, etc. Consultation with Dúchas and other conservation and/or ecology groups will play an important role in these situations.
Community imperatives
Community imperatives will be taken into consideration, particularly where cutaway
bog areas are close to settlement areas. Any prominent needs of the local community
will be considered, for example, there may be a local requirement for grassland and/or
industrial development land. Community involvement ultimately would depend on the
interest of the local people. An example of this is the Boora Parklands in Co. Offaly.
Since the development of (a) extensive wetland, grassland and woodland communities
at Turraun, (b) amenity lakes and (c) grassland within the Boora parkland area, the
local community has incorporated these developments into their community
development strategy (Anonymous 1998; Barron et al. 1994). This will be a case study
for consideration by other community groups that lie at the margins of cutaway bog. In
the case of Killaun bog in Co. Offaly, a portion of this bog was handed over to a local
school and has contributed greatly to a number of aspects of the secondary school
curriculum including geography, biology, social studies, history, art and economics.
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 63
Archaeological interest
Bord na Móna manages the archaeological implications of peat extraction under a
formal agreement with Dúchas. Under this agreement mitigation measures are applied
under licence from Dúchas where archaeological sites are discovered in the peat. In
certain cases portions of bog are set aside either temporarily or permanently where
mitigation/excavation is not a preferred option in the short term. When the bog is
cutaway these areas will continue to be preserved because of their archaeological
importance. Discussions have begun with Dúchas as to the maintenance of the
required conditions (moisture content, etc.) in these areas in order to prevent
deterioration of the archaeology. Dúchas will be consulted in deciding the best
approach in all such cases.
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 64
2.3 After-use Options
A number of after-uses have been proposed for industrial cutaway bog. The main after-
uses are grassland and forestry development (commercial) and establishment of fen
communities (the non-commercial wetlands option). A general description of the
methods of developing the cutaway bog for these after-uses and inter-related issues is
outlined here. A more detailed account can be attained from the references listed (See
References). The main features of these after-uses are outlined here under the following
headings:
• Technical parameters
• Development works
• Supporting infrastructure
• Indicative costs
• Nutrient requirements
• Timeframe
• Influencing issues
2.3.1 Grassland
The grassland after-use option has been developed over the last thirty years on cutaway
bog in the midlands. Grassland development has been concentrated largely in Co. Offaly
and to date approximately 1,000ha of land has been developed successfully and sold to
local farmers in varying lot sizes. Grassland development was also studied on Atlantic
blanket bog cutaways but inclement weather conditions and nutrient poor conditions led
to the developments being economically inviable.
Technical parameters
The cutaway bog must be drained by gravity drainage to establish sustainable commercial grassland. Peat depth must be less than 1m deep on 75% of the site and the underlying soil should comprise boulder drift and/or silty clay that is devoid of large boulders in the top 15cm.
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 65
Development work
Development of the cutaway bog for grassland requires initial, overall levelling of the
site. The area is then deep ploughed, mixing all of the residual peat and 15cm of the
underlying soil. Once ploughed, the area is left for twelve months that is followed by
re-levelling to further the mixing of peat and soil. This peat and soil mix is then left to
settle for a further twelve months. This period is required to identify and subsequently
rectify any drainage deficiencies. The seedbed is then prepared and any fossil timber is
removed. At this stage nutrients are applied according to the nutrient requirement of
the soil. Grass seed is sown between mid-July and mid-September.
Supporting infrastructure
The necessary infrastructure for sustainable grassland developments requires (a)
development of road access; (b) installation of water supply; (c) erection of fencing
and (d) installation of open drainage channels.
Indicative cost
The cost of developing grassland is generally in the range of €5,000-€6,000/ha. Costs
can be elevated however, where infrastructure costs are increased due to on-site
conditions.
Nutrient requirements
The base level of available phosphorus and potassium in peatland systems is relatively low. Following soil test results, the
nutrient status of the ploughed peat and soil is elevated to meet grass growth requirements (8-10ppm P and 150ppm K at a pH of
5.5-6). Once this level is achieved, the normal annual addition of nutrients to match stocking levels is all that is required.
Timeframe
The exposed soil is left in the ploughed state for at least 12 months during which its structure is significantly changed due to the
action of frost, rain, sun and wind. When re-levelled and mixed the area is then allowed to settle for a further 12 months, during
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 66
which time the necessary drainage is installed. From initial levelling to grass establishment, the time for grassland establishment
is two and half to three years. Work can only be undertaken in the drier months and therefore, the length of the dry period in any
year influences the timeframe of development.
Influencing issues
A number of issues must be considered as follows:
• The area developed as grassland must be capable of carrying the infrastructure costs.
• There must be a market for the land developed.
• Agricultural support mechanisms are continually changing and could impact
negatively or positively on land yet to be developed.
2.3.2 Forestry
Afforestation of cutaway bog has been under development for the last thirty years
however, a number of factors have hindered the successful establishment of crops. The
afforestation of industrial cutaway peatlands is now under active research through the
BOGFOR programme, which is co-ordinated by the Forest Ecosystem Research Group,
U.C.D. The research programme is funded by COFORD, Coillte and Bord na Móna and
is now in the fourth year of a fifteen-year programme. The aim of the research
programme is to develop commercially viable techniques for afforestation of cutaway
bog and to overcome difficulties with growing trees that have arisen in the past (Jones &
Farrell 2000).
Technical parameters
The cutaway bog must be drained by gravity drainage. Peat depth must be more than
0.5m and less than 2.5m. In general, an acidic cutaway bog surface is required with
minimal influence from the underlying soil.
Development works
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 67
Research to date indicates that the growing medium into which the trees are sown must be aerated and therefore, some disturbance of the residual peat prior to planting is necessary. Installation of the appropriate drainage infrastructure prior to planting is a major factor and this in turn is related to site-specific characteristics.
Supporting infrastructure
The available infrastructure (peat production infrastructure) is usually adequate to establish the forest but at thinning stage (year 20) it will be necessary to create a road network to facilitate extraction of timber from the site.
Indicative costs
Currently costs of development, planting and after-care are approximately
€2,800/ha.
Nutrient requirements
As with grassland, the peats require the addition of phosphorus and potassium for
commercial tree growth. A major part of the BOGFOR project is to research (a) the
timing of fertilisation; (b) the potential nutrient run-off and (c) mitigation measures
such as the creation of wetlands to intercept drainage waters etc. The present
recommendations are to apply 350 kg P/ha as ground rock phosphate and 250kg K/ha
as muriate of potash in a split application (two applications - year 1 and year 3 or year
4).
Tree species
Species selection is a key task of the BOGFOR project and the recommended planting
species (January 2002) are as follows:
Conifers: Norway Spruce, Hybrid Larch
Hardwoods: Oak, Birch, Alder
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 68
Timeframe
Preparation of the site takes place in the summer of initial year of development, while tree planting can commence in the following planting season.
Influencing issues
Currently grant aid is not available for the afforestation of non-agricultural land and
this policy is under active negotiation with the Forest Service. Another influencing
issue will be the outcome of the BOGFOR research programme.
2.3.3 Wetlands
The establishment of wetland systems has been well documented for midlands raised
bogs, with extensive alkaline fen systems establishing on shallow minerotrophic peats
(Egan 1995, 1998a, b; Feehan & Kaye 1998; Kavanagh 1996, 1998; O’Connor 2000;
O’Connor & Reynolds 2000; Rowlands 2001; Rowlands & Feehan 2000 a, b; Trodd &
Murray 2000). The success of this after-use option can be readily viewed at the Turraun
wetland site, which has established over the last twelve years and forms part of the Boora
Parklands. An alternative research programme has been ongoing in the west of Ireland to
study the establishment of wetland communities on industrial cutaway Atlantic blanket
bog (Farrell 2001; Farrell & Doyle 1998, 2002). Rewetting of the cutaway Atlantic
blanket bog has proven successful in establishment of poor fen communities and also
embryonic peat-forming communities, which are characterised by typical peatland
species with an active layer of Sphagnum (peatmosses). The wetland option is considered
a stable and sustainable after-use that could play a significant role in enhancing the
national wildlife habitat area and biodiversity resource. There is minimal requirement for
maintenance, reaching a stable equilibrium as natural succession occurs.
Technical parameters
The designated site must be capable of being permanently inundated with water for twelve months of the year.
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 69
Development work
In order to maintain a wetland system, the peat drainage infrastructure must be
reversed. This usually involves the removal of pipes and blocking of field drains to
impede the movement of water and create inundated areas. Other work required
includes the creation and stabilisation of peat embankments, where appropriate. These
developments apply to both minerotrophic and ombrotrophic cutaway bog areas. All
development work for wetland creation is site-specific and will have to take
underlying contours and variability of peat depth into consideration.
Supporting infrastructure - not necessary
Indicative cost
The cost of reversing drainage of production areas (blocking field drains, pipes, etc.)
currently runs at €320/ha.
Nutrient requirement - not relevant
Timeframe
Development work must be carried out during dry summer months. Inundation of the cutaway bog generally begins at the onset of wet months. Colonisation by aquatic plants usually begins as soon as the area is flooded, passing through a pioneer colonisation stage that is followed by successional development stages that comprise alkaline fen communities where there is minerotrophic influence and poor fen and/or embryonic peat-forming communities in ombrotrophic conditions. Revegetation commences within the first year of rewetting and generally within three to five years a continuous vegetation cover is established.
Influencing issues
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 70
The principal issue that would affect the creation of alkaline fen is the degree of removal of the peat. Peat extraction should generally proceed to the degree to which the residual peat is inundated with alkaline ground waters, which in turn would support typical alkaline fen species. Where ombrotrophic peat remains the most important factor is to maintain waterlogged conditions (either maintaining the water-table at the peat surface and/or permanent inundation).
2.3.4 Other options
A number of other after-use options have been proposed for industrial cutaway bog,
but these have not been studied at the same level as the grassland, forestry and wetland
options. These alternative after-uses are generally considered niche opportunities and
are either at early developmental stages or at the initial proposal stage. One example of
this niche opportunity is the established wind-farm at Bellacorick. This wind-farm was
established on an area that was comprised largely of cutaway bog and isolated from
large settlement areas, in a location where the wind regime proved economical for
electricity generation. The viability of any wind-farm depends on the wind regime and
this varies with altitude and proximity to coastal areas. Other options include the
establishment of general amenity and/or angling lakes and industrial development
sites. It is likely that other potential after-uses will come to light, particularly where
consultation with other interested parties is ongoing. These after-uses may be subject to
planning permission and/or Environmental Impact Assessment depending on statutory
requirements.
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 71
3. CUTAWAY BOG REHABILITATION PLANS
At this point a general overview of Bord na Móna policy towards industrial cutaway bog
has been outlined, as well as a description of the factors influencing the range of after-
uses that have been proposed to date and a description of the main features of each after-
use option. There are however, more practical aspects to consider such as when does
rehabilitation commence and how will rehabilitation plans be developed. In an attempt to
deal with these issues the triggers for development of a rehabilitation plan and its
implementation are outlined below.
3.1 Triggers for Development and Implementation of a Rehabilitation Plan
A series of stages and/or triggers (1 to 6) can be identified in the development and
implementation of cutaway bog rehabilitation plans. Following from stage 1 below, each
subsequent stage deals with individual Bord na Móna Works, e.g. Blackwater Works,
Oweninny Works, etc. The stages and/or triggers are outlined as follows:
1. January 2002: A broad-based plan is developed for all Bord na Móna holdings (see
Table 1 and this document). Each Bord na Móna Works continues to report on
progress of cutaway rehabilitation and potential future work as part of the Annual
Environmental Report.
2. Isolated areas of cutaway bog become available but are dispersed within larger
production areas. Even though extensive peat extraction is ongoing, at this stage a
general impression of what conditions will remain on cessation of peat extraction can
be attained and possible after-uses identified (preliminary outline of after-uses noted).
3. The final peat drainage infrastructure is installed and an executive decision is taken
on the level of peat extraction that will proceed within the bog unit, i.e. what further
depth of peat will be extracted, what acreage of bog will be required to meet market
demands, etc. Generally at this stage the operations in the bog would be winding
down and/or a realistic time-plan established for closure of the bog unit. At this stage
a rehabilitation plan should be developed for the cutaway bog, ideally incorporating
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 72
time frames, cost estimates and realistic objectives. Consultation with interested
parties will be conducted.
4. Hydrologically isolatable units of bog are available. Rehabilitation can commence
within discrete areas of cutaway bog, e.g. the Boora Parklands complex.
5. The entire bog out of peat production. Only at this point can the complete
rehabilitation plan be implemented, as well as decommissioning procedures for
workshops and workstations.
These stages and triggers will occur within the next thirty years for all bog units in Bord
na Móna ownership. Within this framework, the most appropriate after-use must be
established on the basis of research and trials conducted and the conditions required for
each potential after-use, while taking all primary and secondary factors into
consideration.
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 73
3.2 Development of a Rehabilitation Plan
An important aspect of each rehabilitation plan will be the completion of a baseline study
of the cutaway bog in each bog unit. A number of aspects will be covered within this
study, including: peat depth and type remaining, a bottom contour map, surface drainage
patterns, a vegetation map and details of site-specific biological and/or physical
parameters that will yield information for the development of a site-specific rehabilitation
plan. Following that, a desk study will be required to look at aspects such as cost,
accessibility, etc. and relevant organisations will have to be consulted.
Development of a cutaway bog rehabilitation plan therefore involves a number of
aspects:
• Triggers for development of the rehabilitation plan as outlined here, will be followed
• A baseline study of the cutaway bog will be carried out at an early stage to evaluate
the conditions (primary factors) and outline potential after-uses
• Potential after-uses will be considered in the light of secondary factors (the best
option for after-use will be determined, See 3.3)
• Consultation with other organisations will be conducted, i.e. Dúchas, etc.
• A rehabilitation plan will be produced based on the best-option after-use(s)
• The rehabilitation plan(s) will be implemented on cessation of peat production *
*In general, rehabilitation of Bord na Móna peat production areas will be implemented as
conditions on site allow and that is typically when peat production ceases completely in
an isolatable unit of bog. However, where there is scope for rehabilitation work to be
carried out, as much work, as possible will be carried out before the complete shutdown
of operations in any one area. This is however, not generally possible for the reasons
outlined already. Bord na Móna are however, committed to rehabilitation and will
complete rehabilitation within a minimal period of time following cessation of
operations. Rehabilitation will also require a number of years with subsequent monitoring
of each site to ensure the work is implemented (the degree of monitoring required will
depend on the chosen after-use).
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 74
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 75
3.3 Determining the ‘Best Option’ After-use
A simple model illustrates the thought pathways that will be followed in selection of
potential after-uses (Fig.2). The model can be used only after an on-site baseline study
has been conducted to yield information on peat depth and type, drainage, etc. While the
baseline study will provide information on physical and biological parameters, other
factors will have to be studied by looking at the area as a whole (accessibility, adjacent
land-use) and consultation with relevant parties (local groups, Dúchas, etc.)
The model begins with an area of cutaway bog that is isolated from adjacent production
bog. Before anything can be established a baseline study, as outlined previously, will be
conducted. This will identify the baseline conditions, such as is there peat remaining, how
deep is the peat and what kind of peat is it, is the topography relatively uniform or
undulating. Following on from that drainage is considered i.e. is the area easily drained or
poorly drained. Once these primary issues have been established, secondary factors come
into play, such as is the area accessible for construction of a road network, etc.
All of these questions, and several others, will be addressed in identifying the most
appropriate after-use for any area of cutaway bog. The model outlined in Fig. 2 shows the
main after-uses and incorporates drainage, peat depth and peat type (See Table 2). Other
factors, such as accessibility are difficult to incorporate into such a model, as relativity
will have to be considered in each case. It should be noted as outlined already that
secondary factors may be an over-riding influence in the selection of an after-use and are
termed secondary here to distinguish from natural restrictions. For example, in a situation
where deep ombrotrophic peat is remaining and the area is well drained, there may be a
potential for afforestation. Market demand however, may be low or the area may be
considered inaccessible. Other options would have to be considered at this point.
The model is simple, yet effective and will be modified as further work is carried out and
a greater understanding of cutaway bog areas is attained.
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 76
Fig. 2
Bord na Móna Energy Ltd. Cutaway Bog Rehabilitation 77
4. GENERAL CONCLUSIONS
Based on the work carried out to date and taking into consideration the main factors
affecting the after-use of cutaway bog areas, a number of general comments can be
highlighted:
• No two cutaway bog areas can be assumed to be the same
• Following that, each cutaway bog has its own characteristic features and will require
a specific on-site physical and biological description before any rehabilitation plan
can be produced.
• It is not possible to predict the conditions that will remain after peat production ceases
completely in any bog, however, based on a knowledge of cutaway conditions to date,
it can be assumed that one or more of the conditions already described to date will be
present.
• It is also not possible to say for definite when peat production will cease in any bog,
as this is related to the continued existence of the peat-fired electricity stations and the
demand for horticultural peat.
• It is possible to gather all the data amassed to date and build a general picture of
possible after-uses and the factors that will affect selection of the after-use(s), which
is the purpose of this document.
• A number of after-uses may be appropriate within one area of cutaway bog,
highlighted the requirement for an integrated use plan that will involve a broad range
of interest, such as Dúchas and local farmers. The Boora Parklands is the best
example of this scenario.
• Following that, any general overview must guarantee that rehabilitation and
decommissioning of cutaway bog will be conducted in such a way that: (a) the after-
use is implemented; (b) the areas will be self-maintaining and/or maintained; (c) an
economic output will be generated where the after-use is considered a commercial
venture; (d) the national wildlife resource enhanced where renaturation is the
objective, as well as (e) contributing to community development and the general good
of the national economy.
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