Since I last wrote about Parteen Weir, see here, it has been in the news for two reasons:
The first is because it is the proposed location for a large water extraction project. It is planned to extract, treat and pipe water from here to Dublin, 160 km away. I was recently at a lecture given to the Irish Branch of the Institute of Structural Engineers by Irish Water where the scheme was outlined. Some of the main points of the presentation were as follows:
- The preferred option is for water to be extracted at Parteen basin, treated and pumped to Dublin via an underground pipe, feeding towns along the route.
- The planned pipe will be a single steel pipe 2m in diameter. A twin pipe solution would be better to provide redundancy, but it was ruled out on cost grounds.
- Part of the project budget of €800 million will be spent on improving to local facilities. This could include improved fish passes at Parteen Weir.
- The level of water take off will be 4 cubic metres per second. This represents 2% of the average flow of the river. But the flow of River Shannon varies considerably, between a low of 10 and a high of 1000 cubic meters per second (based on over 80 years of measurements).
- As part of this scheme approx. 8000 km’s of water mains in Dublin will be repaired to stop leaks. The leakage rate is currently estimated to be 40% and the plan is to reduce this to 20%. Below 20% it is reckoned to be uneconomic to repair the leaks.
The second reason Parteen Weir was in the news was as a result of the heavy winter rainfall which caused flooding on the River Shannon during last December. I happened to be in the area at the time when over 400 cubic metres of water per second was flowing through the weir, the remaining river flow being diverted through the turbines at Ardnacrusha. 400 cubic metres is a very high flow rate through the weir and there was some minor flooding downstream of the weir with the walking route I previously used along the river was under water, see link here. I took a photo of the stone arch in the village of O’Briens Bridge which was completely filled with water. See below for a comparison with photos of more normal water levels there.
The water levels have since subsided thankfully.