§ Mr. SpearingTo ask the Secretary of State for the Environment if he will state, or investigate, the extent to which water in the aquifers of the London geological syncline could be used in greater volumes, either in the public water supply or other purposes; what is the current cost of obtaining potable water from this source; and what capital and revenue costs would be incurred in using sufficient water for these uses so as to stabilise the height of the local water table.
§ Mr. AtkinsThe National Rivers Authority has, at the request of the Department, improved the monitoring network of groundwater levels in the London area, and has worked closely with Thames Water Utilities Ltd. to investigate the potential of this resource to provide additional water for public supply. The TWUL is currently involved in several groundwater schemes in the London area including recharge and abstraction schemes in north London and south London and an exploratory scheme in central London.
In 1989, the Construction Industry Research and Information Association published a report "The Engineering Implications of rising groundwater levels in the deep aquifer beneath London", part-funded by the Department. Since that time, the TWUL has investigated 20 sites in central London. Of these, seven provided yields of sufficient quantity and quality to be of potential use for public supply. However, the development of this resource for public water supply is relatively expensive. I am informed that the TWUL is not likely to require it in the short or medium term because of the success of the north London recharge scheme, improved leakage control and the construction of the London ring main.
508WCapital and operational costs for public water supplies are a matter for the water undertakers, within the price limits determined by the Director General of Water Supplies.