MODELING OF RISING GROUNDWATER LEVELS IN THE CHALK AQUIFER OF THE LONDON BASIN

The rising groundwater level in the confined chalk aquifer of the Cent ral London Basin syncline has been the subject of study and concern fo r over a decade, Settlement effects in deep foundations and the floodi ng of tunnels are seen as the main problems arising from resaturation of the London Clay. The Thames Region of the National Rivers Authority has undertaken to formulate a strategy to monitor and control the ris e in groundwater levels. Using a finite element, multi-layer computer model of the London Basin aquifer, various scenarios involving groundw ater abstraction have been modelled and analysed up to the year 2040. The objective of the study has been to optimize the location of potent ial groundwater abstraction points and the quantities pumped to provid e the most effective control of regional groundwater levels. The water available is seen as a valuable resource for public water supply in a n area where there is a demand deficit. The economics of utilizing thi s resource are complicated, however, by variations in water quality, t he cost of treatment and the availability of lower cost water from oth er resources in some areas.