Summary of supply sources
We obtain our water resources from three sources: Blithfield Reservoir, the River Severn and groundwater from 25 sites across our supply area. Approximately 40% of the total water available to us is taken from groundwater sources and the remaining 60% from the two surface water sources.
Groundwater is abstracted from over 60 boreholes (2-3 per source), all of which allow water to be pumped from the Triassic Sandstone aquifer. This aquifer is very porous (like a sponge) which means that it can hold large quantities of water in between the sand grains and in cracks in the rock. As the sandstone can hold large volumes of water the water levels within the sandstone do not fall very far in dry periods. This makes the groundwater sources a very reliable supply of water.
Blithfield Reservoir is an impoundment reservoir with a capacity of approximately 18.224 billion litres of water. It was formed in 1953 by the construction of a dam across the River Blithe. The raw water is taken out of the reservoir by pipeline to the treatment works at Seedy Mill near Lichfield before going into the distribution network. (For further information on Blithfield reservoir, its construction and history, visit our Blithfield Website.)
The River Severn is a regulated river i.e. flows in the river are augmented by inputs from both groundwater and reservoirs at its head at times of low flows. The regulation of the River Severn is controlled and operated by the Environment Agency who monitor and report on the situation regularly. We take water from the River Severn at Hampton Loade where it is stored in Chelmarsh Reservoir before being treated and distributed.
Current water resources position at the end of October 2013
Long term rainfall patterns for the period April to the end of October 2013 were 92% of the ten year average. The rainfall for October 2013 has been exceptionally high at 172% of the ten year average. Blithfield Reservoir storage level was 75% at the end of October. There are no groundwater resources issues. The overall water resources position is healthy.
We use the level in Blithfield Reservoir as the main indicator of resource availability. Regular analyses of refill scenarios for Blithfield Reservoir are routinely carried out and the levels are monitored continuously. Blithfield Reservoir storage level was 75% full at the end of October, which is above the drought monitoring curve.
No river regulation alerts were posted for the River Severn during October and the regulation season has now finished for the year.
Groundwater levels in the Sherwood Sandstone aquifer do not tend to react rapidly to short periods of high or low rainfall; current groundwater levels are comfortable. They have continued to recede as groundwater recharge is normally delayed.
Rainfall (recorded at our Seedy Mill treatment works) for October was 172% of the ten year average figure.
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