Protection of water quality
Groundwater is the principle source of water in Offaly. 72% of the people of Offaly receive water from schemes with groundwater sources, compared with a national average of less than 25%. Because of our reliance on groundwater, it is essential that we protect this natural resource. To do this, a groundwater protection scheme has been adopted for all public and group water supply sources in Offaly.
This scheme, which was first put in place in 1987, was based on a relatively simple scheme proposed by the Geological Survey of Ireland and utilising available hydrogeological information.
Since 1996, a program has been in place to update the groundwater protection plan in line with guidelines prepared by the Geological Survey of Ireland, Environmental Protection Agency and the Department of Environment Heritage and Local Government. Under this new scheme, Groundwater Source Protection Zones have been established for groundwater sources at 5 group water schemes and 10 public schemes.
The scheme consists of two closely interlinked components:
- Land surface zones – based on hydrogeological concepts and information on aquifers and vulnerability ·
- Groundwater protection responses – for potentially polluting activities
The groundwater protection responses provide guidelines on the acceptability of activities, investigation requirements and, where appropriate, the likely planning or licensing controls.
Treatment Practices
To ensure a clean and wholesome supply of water and to meet EC regulations, all water must be treated. Depending on the source of water used for drinking water supplies and its quality, treatment can vary considerably from disinfection up to full physio-chemical treatment.
Groundwater, which is the source for a large proportion of the drinking water in Co. Offaly, receives just a precautionary dose of chlorine to provide disinfection. This is due to the excellent quality of the groundwater at our sources.
Surface water is the source for 4 drinking water supplies in Co. Offaly, namely; the River Shannon for Banagher Regional Water Supply, the Camcor river for Birr water supply, the Gageborough river for Clara Regional water supplies and Gorragh and Clodiagh rivers for Tullamore's water supply.
These river sources receive full physio-chemical treatment, consisting of coagulation, floculation, sedimentation, filtration, pH correction and disinfection.