An Analytical Baseflow Coefficient Curve for Depicting the Spatial Variability of Mean Annual Catchment Baseflow

Catchment baseflow is jointly controlled by climate and landscape properties. Previous studies have recognized that spatial variability of mean annual coefficient (BFC = , ratio to precipitation) primarily aridity index storage capacity. However, an analytical solution BFC in terms the dominant controlling factors has not yet been established. The objective this study was develop curve depict based on “limit” concept Budyko framework. relates capacity without resolving complex interactions between evapotranspiration generation. proposed showed that, arid catchments, limited available water (precipitation, P) and, humid both energy (potential evapotranspiration, Ep) catchment retention capability (ratio P, i.e., Sp/P). Observed hydrological data from 950 catchments Australia, conterminous United States Kingdom with diverse hydro-climatic conditions 0.001–0.650) were collected demonstrate developed curve. Results captured observed (R2 0.75, RMSE 0.058). Mean estimated agreed well 0.86, 0.19 mm). provides for understanding how control baseflow, will improve predictability at ungauged basins.