A simple overland flow calculation method for distributed groundwater recharge models

摘要

A method to improve the calculation of overland flow in distributed groundwater recharge models is presented and appliednto two sub-catchments in the Thames Basin, UK. Recharge calculation studies tend to simulate the runoff flow componentnof river flow in a simplistic way, often as a fraction of rainfall over a particular period. The method outlined in this studynintends to improve the calculation of groundwater recharge estimates in distributed recharge models but does not presentnan alternative to complex overland flow simulators. This method uses seasonally varying coefficients to calculate runoff fornspecified hydrogeological classes or runoff zones, which are used to model baseflow index variations across the basin. Itnemploys a transfer function model to represent catchment storage. Monte Carlo simulation was applied to refine the runoffnvalues. Decoupling the runoff zones between the two sub-catchments produces a better match between the simulated andnobserved values; however, the difference between observed runoff and the simulated output indicates other factors, suchnas landuse and topographical characteristics that affect the generation of runoff flow, need to be taken into account whennclassifying runoff zones. British Geological Survey  NERC 2011. Hydrological Processes  2011 John Wiley & Sons, Ltd.