A DRASTIC reduction in sheep numbers is required to prevent further environmental damage by overgrazing in upland areas, according to the Environmental Protection Agency.
In a detailed report on water quality in Ireland, covering the years 1991 to 19,94, the EPA concludes that the situation is deteriorating, with a 5 per cent increase in slight to moderate pollution of rivers.
The main finding is that, whereas water quality remains good overall, increasing eutrophication (artificial enrichment due to excessive levels of nutrients) "poses a serious threat, especially to our rivers and lakes".
Agriculture is identified as the largest single source of pollution, suspected of causing 46 per cent of "slight pollution" cases, 45 per cent of "moderate pollution" cases and 25 per cent of "serious pollution" cases, measured in terms of river channel length.
For the first time, the EPA identifies sheep overgrazing as a "serious environmental problem" and says it has caused widespread soil erosion, leading to excessive siltation of lakes and rivers which, in turn, is affecting stocks of trout and salmon.
The report suggests that major flaws in administrative procedures were to blame for allowing "such extensive damage" to be done before making "any serious attempt to control it". Early warnings either "went unheeded or were dismissed out of hand", it says.
"Such messages should be taken not as threats to vested interests, but as early warning signals designed to allow minor changes in policy at an early stage which will prevent serious and perhaps irreversible environmental and economic damage at a later stage.
"Both the landscape and the rivers and lakes are intrinsically important as well as being of immense current and future economic value in terms of tourism and biodiversity. At present, all of these resources are jeopardised by excessive sheep numbers."
The EPA report also blames intensive farming - particularly the over-use of fertilisers - for contributing to the eutrophication of rivers and lakes, as well as discharges of sewage and industrial effluent.
"There seems to be little doubt that changes in agriculture, starting in the 1960s, have played a major part in the deterioration of the freshwater resource over the last 25 years", particularly the spreading of animal slurries on land, according to the report.
Eutrophication was also affecting the recreational and amenity value of rivers and lakes. "The presence of large accumulations of planktonic or attached algae along lake shores or on coastal beaches is unsightly and off-putting for bathers and strollers", it says.
"This is a matter of particular concern in Irish waters because of its potential impact on the more sensitive game fish and the fact that the quality of water abstracted for public supply. . . may be adversely affected by the presence of large amounts of algae."
Although the situation would be relieved by the installation of upgraded sewage treatment plants in towns along the waterways, the report suggests that it will be more difficult to deal with the problems presented by intensive agriculture such as the switch to silage-making.
To reverse the current trend in water quality, the EPA recommends that measures be adopted to minimise the potential of agriculture to cause enrichment of surface waters with phosphates. In some locations, it says, additional sewage treatment is required.
