Good water quality is an essential part of a healthy environment that benefits everybody. Living in a catchment that has clean and healthy waters can help communities to have a better quality of life and is a vital element of a thriving economy. There are a number of factors within a catchment, known as “pressures” that may have an impact on our waterbodies. Significant pressures on waterbodies may include: agriculture, hydromorphology, forestry, waste water, and extractive industries.
In Ireland, we have a total of 4,842 water bodies of which just over 1,600 are considered to be “at Risk” of not meeting their environmental objectives as required under the Water Framework Directive. Just under a half of these (46%) are impacted by a single significant pressure, while the remaining water bodies (54%) are impacted by more than one significant pressure.
The EPA has determined that the risk profile of high status objective waterbodies is different to the general risk profile across water bodies nationally. This is in part due to the fact that high status objective (HSO) water bodies tend, by and large, to be located in remote upland areas. In the case of those HSO waterbodies at risk of not meeting their objectives, the EPA has determined that 29% were at risk from hydromorphological pressures, 22% from agriculture, 20% from forestry, 11% from identified human pressures, 5% from extractive industries (peat and quarrying) and 4% from domestic waste water.
Hydromorphology, is a relatively new discipline which is described in the Water Framework Directive . It refers to the physical character of the river and includes the flow of water in the river, the course the river takes or the form and shape of the river channel.
About one tenth of the land in Ireland is covered by commercial forestry. Commercial forestry is considered to be a significant pressure in the case of about 20% of our high status objective waters bodies which are “at Risk” of not achieving their water quality objectives.
Forestry activities can impact on water quality by the release of nutrients and sediment to rivers and lakes. Forestry may also cause acidification, physical changes to habitats and changes in water level and/or flow.
Agriculture is the most common land use in Ireland, covering almost two thirds (65%) of the country. It has been identified as a significant pressure in the case of 22% of high status objective water bodies which are at risk of not meeting their water quality objectives.
The most common water quality problem arising from agriculture is excess nutrients, giving rise to eutrophication. Phosphorus is typically the issue for rivers and lakes, and too much nitrogen for estuaries and coastal waters. Excess ammonium may also be a problem in some waterbodies.
Peat extraction for commercial or domestic purposes, and modification or drainage of peatlands for other uses such as forestry or agriculture, has been identified as a significant pressure. The extractive industry has been identified as a significant pressure on about 5% of high status objective water bodies which are at risk of not meeting their water quality objectives. This is the fifth most prevalent significant pressure type in high status waterbodies.
Domestic waste water treatment systems (DWWTS), mostly septic tanks, are used by householders to treat their sewage.
If properly designed, sited and installed, septic tank and other on site waste water treatment systems can do an excellent job of removing contaminants such as nutrients, organic matter and microbes from the waste water generated in our homes. This allows the treated water to be released back into the environment without causing either pollution of waters or health problems.
