Estimating runoff–recharge in the Southern Lincolnshire Limestone catchment, UK

Abstract

This article addresses the problem of aquifers where recharge can arise from runoff from less permeable areas. A distributed model is described which is used to estimate the runoff from various strata, this runoff can subsequently infiltrate into the aquifer as the water flows onto the permeable areas of the aquifer system. The approach is illustrated by a Limestone aquifer; in the model, direct percolation, infiltration, soil moisture storage, minor aquifer storage etc. are considered for areas of 1km2. Runoff directed down the catchment, infiltration into the aquifer system can occur at the margins of the low permeability areas or when the streams pass onto the aquifer outcrop. Parameters of the runoff model are selected to reflect the physical processes, subsequently they are modified to match field measurements of runoff at three gauging stations located on the less permeable sub-catchments. The water balance and runoff calculations are carried out each day, the averaged values over half-monthly periods are used as input to a regional groundwater model.