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Physical hydrogeology 63

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Regional groundwater flow in the Lincolnshire Limestone aquifer, England
2.10

The Lincolnshire Limestone aquifer in eastern England is part of a From a consideration of catchment water balances (see Section
relatively uniform stratigraphical succession of Jurassic strata that 8.2.1) and the use of numerical modelling, Rushton and Tomlinson
dip 1–2° to the east. The pattern of recharge and groundwater flow (1999) showed that recharge to the Lincolnshire Limestone aquifer
in the aquifer is influenced by various geological and hydrological occurs as direct recharge in the western outcrop area and as runoff
controls as shown in the schematic cross-section of Fig. 1. The Upper recharge and downward leakage from the low permeability boulder
Lias Clay forms an effective impermeable base to the limestone clay and confining strata. The boulder clay produces large volumes
aquifer. In the west of the section, the limestone is 6–8 km wide at of runoff which commonly recharges the limestone through the
outcrop. Formations overlying the limestone have a significant many swallow holes that occur at the edge of the boulder clay. In
effect on surface water and groundwater flows since they form an places, the West Glen River and East Glen River incise the confining
alternating sequence of limestone aquifer units and confining beds strata and provide a mechanism for localized groundwater dis-
of low permeability consisting of clays, shales and marls. The upper- charge from the limestone aquifer. Further east, the groundwater
most deposits of the confining strata include the Oxford Clay that potentiometric surface is above the top of the aquifer, with over-
extends to the east of the area where the continuation of the lime- flowing artesian conditions developed in the Fens. In this region
stone below the Lincolnshire Fens is uncertain. Quaternary glacial of the aquifer, slow upward leakage of the regionally extensive
deposits consisting mainly of boulder clay (glacial till) and sands groundwater flow system is expected, although the large volumes of
and gravels occur in the west of the area and also in west–east groundwater abstracted in recent years for public water supply has
drainage channels. disrupted the natural flow patterns and drawn modern recharge
water further into the confined aquifer.

Fig. 1 Schematic cross-section of the Lincolnshire Limestone aquifer in eastern England showing mechanisms of groundwater recharge
and directions of local and regional groundwater flow. After Rushton and Tomlinson (1999).

the identification of aquifers and aquitards and the 2.14.1 Hydrogeological environments of the
mechanisms of groundwater flow are to be properly United Kingdom
understood. To illustrate the range of geological
conditions in which groundwater resources can The United Kingdom is fortunate in the variety of its
occur, the following description is based on the wide rocks, structures and natural resources. As shown in
variation in groundwater occurrence in the United Fig. 2.27, the principal groundwater resources are
Kingdom. located in the Midlands and south-east of England