THE CHALK AS A KARSTIFIED AQUIFER - CLOSED-CIRCUIT TELEVISION IMAGES OF MACROBIOTA

The use of closed circuit television (CCTV) imaging in the Chalk aquif er of the Thames catchment of southern England, has shed much light on the aquifer's flow mechanisms. CCTV images indicate that flow to a Ch alk abstraction borehore is typically via a limited number of highly t ransmissive solution-enhanced fracture features. These bear some simil arities to conduits found in true karstic aquifer systems, and have im plications for the modelling of mass transport in the Chalk aquifer. A nother feature, typical of karat aquifers, noted during CCTV surveys i s the occasional presence of macroscopic biota, arthropods and annelid s, apparently inhabiting the Chalk aquifer system.