Chilterns South-West Chalk Operational Catchment

About

The SW Chilterns Groundwater Body (GWB) describes part of the Chalk Group that lie beneath the Chilterns. The SW Chilterns Chalk GWB is located on the northern part of the London Basin syncline but on the southern dip slope of the Chilterns. The Chiltern Scarp Chalk GWB coincides with the northern side of the Lower River Thames Catchment. The River Wye and other streams such as the Hambledon Stream and Hughendon Stream flow from springs in the Chilterns and on into the River Thames. The Chalk consists of water-bearing permeable strata that provide a high level of storage. Since they support regionally important groundwater supplies these aquifers are classified as Principal Aquifers. The Chalk is exposed at the surface mainly in the valleys in the SW Chilterns Chalk GWB and in these areas the Chalk is susceptible to vertical migration of chemicals, including fertilisers. On the hill tops the Chalk is confined by superficial clays and head deposits so is generally protected from vertical migration of chemicals used at the surface. Some of the valleys are quite steep sided such as that at High Wycombe.