The scenic beauty of the lakes of Killarney, encompassing a rich landscape of lakes, mountains and woodlands, are one of the crowning jewels of Ireland's tourist industry, attracting an estimated one and a half million visitors to the area each year. The largest of the lakes, Lough Leane, gives its name to the lake's catchment, which contains numerous tributary rivers, streams and lakes, and drains an area of 560 km2. The principal tributaries are the River Flesk, the Deenagh River and the Gearhameen River, while the principal lakes are the Upper Lake, Muckross (Middle) Lake, and of course, Lough Leane (Lower Lake).

The catchment and Lough Leane in particular, is renowned as one of Ireland's premier trout and salmon fisheries, although one that is under significant threat. Both local angling groups and the Environmental Protection Agency (EPA) have noted the serious decline of the river and lake water quality within the catchment over the last 30 years, such that by 1997, Lough Leane was classified as hypertrophic (or highly polluted). This decline in water quality is principally attributed to increased levels of nutrients, most significantly phosphorus, being transported via the rivers to the lakes, which has led to eutrophication in recent years. Eutrophication is the enrichment of waters by nutrients beyond natural levels, causing the accelerated and undesirable growth in microscopic algae and other forms of plant life. The growth in algae can periodically manifest itself as an algal bloom, resulting in the deprivation of oxygen in the lower depths of the lake and the consequent serious decline in the lake's plant, insect and fish life.

In response to the appearance of a severe algal bloom outbreak in Lough Leane during the summer of 1997, Kerry Co. Council set up the Lough Leane Working Group to co-ordinate efforts to monitor and manage water quality within the catchment. The Working Group comprises representatives of Kerry Co. Council, statutory bodies (e.g., the South Western Regional Fisheries Board, Teagasc and the Forest Service), land users (e.g., the IFA and Coillte), and interest groups (e.g., local angling and environmental groups). A project proposal for a Catchment Monitoring and Management System was quickly prepared and submitted to the Department of Environment and Local Government in the Autumn of 1997, and funding approval was given in November of that year. After a public tendering process consultants were appointed to the project in July 1998.

The Lough Leane Catchment Monitoring and Management System is to run for a three-year period (July 1998-July 2001). It is sponsored by the Department of Environment and Local Government, and is being implemented by Kerry Co. Council. Expenditure on the project is in excess of £1 million, and has been supported by a major £12.6 million investment in wastewater treatment infrastructure, which has been 85% co-financed by the European Commission through the Cohesion Fund.

This Monitoring and Management System is a major catchment-based initiative, aimed at arresting the eutrophication process and restoring the rivers and lakes to a satisfactory state by reducing phosphorus inputs from all sources. A further aim of the project is to identify and quantify all significant point and diffuse sources of pollution, in particular from local authority activities, agriculture, forestry and septic tanks. A point source of pollution is another word for a single source of pollution such as a sewer pipe. Diffuse sources of pollution originate from multiple sources such as run-off from a fertilised field.

One of the first jobs tackled by the project consultants was the development of a Geographical Information System (GIS) for the catchment, to correlate data on geology, hydrology, land use, river and lake water quality. In relation to the forest sector, Coillte's Southern Region staff provided data on company-owned forests, in particular tree species, age, and fertilisation history over the previous five years in the catchment.

After the data were collected, four special subcatchments were selected for a detailed study to establish an understanding of diffuse pollution sources. These special study areas were located in:

1. the Deenagh Headwaters Subcatchment (Dairy/Drystock farming);
2. Lough Guitane Subcatchment (sheep farming);
3. River Flesk Subcatchment (Septic Tanks); and
4. Clydagh Valley Subcatchment (mainly forestry).

Studies conducted in these catchments included: water quality monitoring; groundwater monitoring at selected boreholes; intensive monitoring of Muckross lake and Lough Leane; detailed study of municipal and industrial effluents; and hydrometric monitoring to quantify river flows.

The Clydagh Valley subcatchment was selected as the special study area for forestry as it had the highest forest cover (36%) in the Lough Leane catchment. The area is predominantly planted with Sitka spruce (90%), some lodgepole pine (9%), and Japanese larch and various broadleaf species (1%). Most of the planting was conducted in the 1970s and 1980s on peat that is underlain by a permeable mineral sub-soil.

A water sampling scheme was put in place in the Clydagh Valley by the project's consultants with some advisory input by Coillte R&D's Site Studies Team in October 1998. The aim of this water sampling programme was to quantify the impact, if any, of forestry activities on water quality on the headwaters of the Clydagh River and to specifically investigate typical forest management practices that are conducted in the valley, such as forest establishment by the private sector and aerial fertilisation of unthrifty forest crops by Coillte.

As no new private sector forest developments were established in the Clydagh Valley subcatchment during 1999, two sites located on other subcatchments in Lough Leane (i.e., the Glanlea and Woodford Rivers) were selected to investigate the impacts of forest establishment and initial fertilisation on water quality in Lough Leane. The first study site consisted of a cluster of four forestry developments with a combined area of 97.5 ha, situated on the headwaters of the Glanlea River, a tributary of the Flesk River. The dominant tree species planted is Sitka spruce. The second study site on the Woodford River is 24.5 ha in size and planted equally with Sitka spruce and ash. The surrounding land cover at both study sites consists mainly of extensive grazing and unimproved grassland/bog. In 1999, granulated rock phosphate was applied by hand at a rate of 350 kg/ha at both the Glanlea and Woodford study sites.

Initial results from both sites show occasional high levels of soluble phosphorus and suspended solids in the water samples that were taken from adjacent tributary streams. Further monitoring will continue at both sites to determine the longer-term impacts arising from these forest developments.

In response to concerns expressed by the Lough Leane Working Group in April 1999, Coillte reduced its 1999 aerial fertilisation programme in the Clydagh Valley, from 4.8 tonnes of elemental phosphorus to 1.3 tonnes of elemental phosphorus. Water monitoring results showed that although elevated levels of soluble phosphorus were observed in forest drains located in the fertilised compartments, little to no significant change in water quality was detected in adjacent tributary streams and the Clydagh River after fertilisation.

The 2nd Interim Report of the Lough Leane Catchment Monitoring and Management System was published in December 2000. This was the first major opportunity for the project consultants to: report on results obtained in the special study areas; give an overview of chemical and biological river water quality in the catchment; and provide a first estimate of the contribution from each sector (forestry, agriculture etc.) to the nutrient loading to Lough Leane. Furthermore, this report would include management proposals specific to each sector that would incorporate protection strategies to improve surface water quality in the catchment.

The results of the report showed that agriculture accounted for the majority of the phosphorus input to Lough Leane at 47%, Urban & Industrial sources in Killarney were next at 15%, followed by Septic Tanks at 12% and Forestry at 3%, with Background (or natural sources) at 23%.

Studies conducted in the Deenagh Headwaters Sub-Catchment Study have identified poor slurry storage facilities on farms as the predominant problem in the agricultural sector, with 70% of the farms examined found to be deficient. The project consultants estimated that up to £3 million was required to be spent on upgrading the farmyards in the catchment. A further £7 million was required to significantly upgrade the Killarney Waste Water Treatment Works in order to process storm overflows which it is not capable of handling at the moment. The project consultants found that septic tanks were a serious cause of concern, with studies in the River Flesk indicating that many are rarely, if ever, de-sludged, and are not regularly inspected or maintained. Furthermore, 20% of the tanks failed to meet the minimum capacity requirements for single dwellings, and up to 50% failed percolation tests.

In relation to specific key management proposals to reduce phosphorus outputs from forested lands, the following were the key recommendations made in the 2nd Interim Report:

1. The long term plans for the redevelopment of the forested areas in the Clydagh Valley should be reviewed and the clearfelling licence altered from a "general felling licence" to a "limited felling licence" to facilitate more appropriate forest planting in the future;
2. Under a "limited felling licence", harvesting in the catchment could be regulated, with strict controls on the location and size of clearfell and time interval between felling of adjacent sites;
3. All replanting should be in accordance with the Forest Service Code of Best Forest Practice;
4. Coillte would be required to submit Forest Management Plans to Kerry Co. Council and the Lough Leane Working Group, detailing, in particular, future plans for aerial fertilisation of forest properties in the catchment;
5. All developers would be required to submit site suitability plans and water quality monitoring data to the Forest Service in support of new forest developments;
6. The Forest Service would undertake random site visits to ensure compliance with the forestry guidelines and to consider the cumulative environmental impacts of new developments in close proximity to one another;
7. Designated sensitive areas in the catchment would not be planted/replanted.

It is envisaged that with the more integrated approach by the statutory bodies to promoting better water quality in the catchment and the implementation of management protection strategies for each sector, the steady improvement in the water quality status observed in Lough Leane will be copper-fastened and continued. Lough Leane, which was initially classified as "highly polluted" prior to the commencement in 1997, changed to the lesser "polluted" status in 1998 and was considered as "moderately polluted" in 1999. According to government phosphorus regulations implemented in 1998, Lough Leane is required to attain "satisfactory" or better condition by the year 2007.

The final report of the Lough Leane Catchment Monitoring & Management System was published in December 2003 by Kerry County Council. Click here for further information on this study.