Chiltern Chalk Scarp Operational Catchment

About

The Chiltern Scarp Groundwater Body (GWB) describes part of the Chalk Group and Upper Greensand Strata that lie beneath the Chilterns. The Chiltern Scarp Chalk GWB is located on the northern part of the London Basin syncline. The Chiltern Scarp Chalk GWB coincides with the southern side of the River Thame Catchment and part of the Middle Thames Catchment. The River Thame is located to the north of the Chiltern Scarp slope hence tributaries of the River Thame flow from springs that emanate from the base of the Chilterns A similar scenario applies to the River Thames where the river has cut through the Chalk outcrop to form the Goring Gap. The Chalk and Upper Greensand Aquifers are 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 for a large part of the Chiltern Scarp Chalk GWB and in these areas the Chalk is susceptible to vertical migration of chemicals, including fertilisers. Where the Chalk is confined by superficial clays and head deposits it is generally protected from vertical migration of chemicals used at the surface.