A single layer soil water balance model for estimating deep drainage (potential recharge): An application to cropped land in semi-arid North-east Nigeria

摘要: Abstract The understanding and quantification of groundwater recharge in semi-arid areas are fundamental to sound management water resources such areas. A soil balance model, if designed adequately represent the physical processes involved, carried out with a short enough (daily) time step, can provide realistic estimates deep drainage (potential recharge) over long periods. We describe single store (single layer) mass model applicable areas, which recognises wetting near surface during rainfall, subsequent availability for evaporation transpiration days following rainfall. allows major hydrological taking place at or soil-vegetation including runoff. Model results presented North-east Nigeria, continuous period 36 years mean annual rainfall was 431 mm (range 321–650 mm) modelled 14 mm 0–95 mm, 23 years having zero potential recharge). modelling indicate that totals not main predictor recharge. temporal distribution daily magnitude antecedent (pre-season) moisture deficit strongest determinants particular location, year. Sensitivity analysis vegetation parameters suggests is most sensitive holding capacity rooting depth. These key determine spatial variability shown be plausible by examination concepts underlie it, comparison field measurements, model's ability qualitative observations crop yield variations from year Future development could include applications other climatic conditions inclusion hydrologic processes.