Diagnosis toward predicting mean annual runoff in ungauged basins

Abstract. Prediction of mean annual runoff is great interest but still poses a challenge in ungauged basins. The present work diagnoses the prediction affected by uncertainty estimated distribution soil water storage capacity. Based on function, balance model for estimating developed, which effects climate variability and capacity are explicitly represented. As such, two parameters have explicit physical meanings, relationships between controlling factors established. from existing data watershed characteristics applied to 35 watersheds. results showed that could capture 88.2 % actual average across study watersheds, indicating proposed new promising underestimation mainly caused area percentage low due neglecting effect land surface bedrock topography. Higher spatial through height above nearest drainage (HAND) topographic wetness index (TWI) indicated topography plays crucial role determining performance basins can be improved employing better estimation including soil, topography, bedrock. It leads diagnosis requirement predicting based newly developed process-based finally.