Engineering Aspects Water Supplies

Ever since it first opened the Basingstoke Canal has suffered from a shortage of water. The main supply came from springs at the Greywell Tunnel, with other sources from small streams. During the period of disuse and dereliction there was a growth in housing and industry which has diverted a significant amount of the available water from entering the canal. In addition, after several recent years of less than average rainfall, the level of the water table became reduced and the canal has suffered from an extreme lack of water. Usually, there is a sufficiency during the winter months when obtusely, there is minimal use. In recent years the canal has had to be closed during the summer and autumn period, (and even some years in the spring as well), just when most users wish to visit the canal.... Therefore it has been necessary to look for additional supplies. A new reservoir has been suggested at the upper end of the canal, but at the present time a more immediately practical solution is the provision of back-pumping facilities at two locations along the canal --- Woodham, from Lock 1 to Lock 6, to supply the Woking pound, and St Johns, from Lock 7 to Lock 11. In addition, there is already a scheme which pumps water from the nearby railway into the canal at Frimley, to supply that pound and the Deepcut Flight. Some consideration has been given to a similar scheme that might take water from the railway at Deepcut. At present, the Frimley and Woodham schemes are in operation. Work on the St Johns scheme to pump water back up the flight of 5 locks (Locks 7-11) started in August 2001.

Water supply The following is the criteria used by the Canal Authority in determining when the canal has to be closed due to shortage of water - When the water is running over the side weirs on the Hampshire pound, all sluices and bypasses are fully opened and the maximum amount of water that we are able to pass down is delivered to the lower pounds of the canal (at this stage the canal is full and our water supply is exceeding our demand). When the water levels drop to weir level on the Hampshire pound (an early indication that water demand is exceeding supply), bypass sluices are partially closed to allow sufficient water to continue to pass down the canal to maintain levels without allowing any water to run to waste. When the water level reaches 2" (50mm) below side weir level on the Hampshire pound, restrictions are placed on the use of locks, initially for visiting boats only (ie. allowing some internal movement between pounds, particularly down to the Woking pound, without losing water from the canal to the Wey Navigation. Once the water levels reach a point at which they are 4" (100mm) below the Hampshire weir level, navigation throughout the whole canal is placed in jeopardy and the Mytchett pound is likely to become unnavigable. The Hampshire and Mytchett pounds together give 20 miles of navigation out of a total of 32 miles of canal. Our prime concern is to ensure that these major stretches are kept navigable even in the dryest of summers.

Some reasons water is short - Water consumption has doubled over the last 30 years. (BBC News, Radio 4, Tuesday 4 November 1997) Adrian Beavey, Director of Communications for Water UK (the "umbrella" group for the UK water companies) said that the south east of England relies on underground water and that it takes a long time for rainfall to drain through the soil. Over the last few years there were some very long dry spells which dried out the soil and stopped rainwater from getting through to replenish the underground supplies. (You and Yours, BBC Radio 4, Wednesday, 15 April 1998)   BACK

Last updated March 2003