The Phosphorus Problem

The primary cause of decline in water quality can be attributed to input of nutrients into lakes and rivers. The main nutrient of concern is Phosphorus, which is a natural nutrient needed for plant growth. Phosphorus is found in abundance in domestic sewage, farmyard run-off, animal slurries, milk washings, silage effluent, artificial fertilisers and many industrial wastewaters. The availability of phosphorus in lakes and rivers needs to be reduced or controlled in order to prevent excessive growth of algae. Algae are a form of plant life, which develops in an aquatic environment and can cause water quality problems. These problems include reduction of dissolved oxygen, which is needed for fish life and growth. Reduction in fish stocks, fish sizes and even substantial fish kills may result. Algae blooms can also make water unsafe for use as a source of drinking water and for bathing in. Algae tend to form scrums along the lake shore, which looks unsightly and decaying algae masses produce bad odours.

Protection Measures under the Phosphorus Regulations, 1998
In 1998 water quality standards were set for phosphorus levels in rivers and lakes with the introduction of the Local Government (Water Pollution) Act, 1977 (Water Quality Standards for Phosphorus) Regulations, 1998. All local authorities had to prepare a plan to achieve the standards by 2007. This involved preparation of a Measures Report setting out the current water quality status, specific measures, targets and timescales for implementation of the plan. Current good water quality has to be preserved, while poor water quality has to be improved.

Updates in the form of Implementation Reports are presented to the EPA on a by-annual basis.


Proposed Measures
A Phosphorus Regulations Implementation Report 2004 was prepared by Leitrim County Council in Dec 2004 with a comprehensive list of targets, actions and timeframes for 2005 to 2007. This programme of work was submitted to the EPA.

Some of the Measures were as follows:

  • Promotion of adequate household sewage treatment systems
  • Promotion of responsible farming practices
  • Issue and review of Licences to discharge to waters and sewers
  • Participation in catchment management committees where shared responsibility of all stakeholders is encouraged
  • Increasing water protection awareness
  • Promotion of responsible forestry practices
  • General enforcement of Water Pollution Act
  • Farm surveys of river catchment areas needing improvement in water quality
  • Investigation of unauthorised urban discharges to waters and sewers
  • Rehabilitation of landfills at Mohill and Carrick on Shannon
  • Control of waste from sheep dip tanks
  • Control of cattle and pig slurries
  • Environmental control on proposed large development and Marinas
  • Control of sewage discharges from boats and provision of pump-out facilities at private marinas
  • Provision of Urban Wastewater Treatment Plants in unsewered Villages.
  • Phosphate removal from all Urban Waste Water Treatment Plants
  • Measures to reduce storm overflows at UWWTP
  • Correct wrong sewer connections
  • Liase with Cavan, Roscommon and Fermanagh Local Authorities regarding catchment management issues
  • Liase with Waterways Ireland re sewage discharges from cruisers navigation on the Shannon and Shannon Erne Waterway
  • Liase with EPA re IPC Licences


  • Ireland Structural and Investment Funds
  • EU European Regional Development Fund