Technical description

The study includes an analysis of the condition of existing water supply infrastructure and levels of leakage as well as an assessment of the viability of the potential sources of supply.

Recommendations for system developments to satisfy current and future demands include upgrading the distribution system through rehabilitation and reinforcement, storage facilities, pumping arrangements, most suitable source, water treatment process selection, design layout and waste disposal and environmental impact of the proposed scheme.

Details

The Halcrow/Mulholland Doherty project team have been appointed by the Donegal County Council to carry out a study of the Regional Water Supply Scheme for Gortahork and Falcarragh towns in Donegal. All aspects of the water supply scheme are included in the feasibility study to identify and propose the optimum design of the new water network and development of viable water resources to supply the area up to 2030.

Some specific issues concerning the existing water supply system include such problems as:

	high level of per capita usage related to high levels of leakage,
	inadequate pipe sizes to deliver water to high level storage reservoirs,
	aluminium carryover from the existing water treatment works,
	insufficient volume and inadequate treatment of the existing water resources.

The feasibility study covers all technical, social and environmental aspects related to the development of the water supply system:

	Statistical analysis of rainfall from local rain gauge stations to identify trends and average and drought year rainfall depths
	Safe yield analysis for all surface water bodies in the study area
	Bathymetric surveys and analysis for the impoundment of lakes to increase storage and available water
	Long term prediction of lake levels versus levels of abstractions
	Network modelling and field testing to analyse operation of the existing network and define leakage and existing consumer demand
	Assessment of future consumer demands and leakage levels taking into consideration the Government requirements on water conservation
	Planning and future development of the network.
	Water quality surveys and analysis of surface water sources to identify suitable treatment processes. - Design of storage reservoirs and new transmission and distribution network
	Environmental impact assessment of all proposals and design of alleviation measures
	Investigation of land ownership and water rights
	Production of reports for central government approval and public information
	Provision of a report of the applicability of water services pricing policy

This project is typical of many such water supply projects being carried out in Ireland. All issues relating to the development of a water supply scheme are investigated including public consultation and a wide range of specialist skills are required to complete the project.