HYDROGEOLOGY OF THE COVENTRY REGION (UK) - AN URBANIZED, MULTILAYER, DUAL-POROSITY AQUIFER SYSTEM

The Coventry Groundwater Investigation has researched the sources and movement of chlorinated hydrocarbon solvents in the groundwater system underlying the Coventry region. The hydrogeological scene is set in t his paper as a basis for the other aspects of the investigation which are reported in the other papers in this volume. The deep, intercalcat ed sandstones and mudstones of the Permo-Carboniferous which underly t he study area, behave as a multilayer aquifer, although individual aqu ifer units are not regionally extensive. The sandstone units are fract ured and behave as dual porosity aquifers, with rapid tracer movement in fractures and diffusion into the low-permeability but porous matrix . The water balance of the groundwater system has changed from natural conditions because of man's influence. Although direct recharge has b een reduced by the impermeable surfaces of roads and towns, substantia l extra recharge arises in the urban areas from leaking water mains.