Risks in hydrological modelling due to uncertainties inuddischarge determination

摘要

Uncertainties in discharge determination may have serious consequences for hydrologicaludmodelling and resulting discharge predictions affecting flood and drought risk assessment and decisionudmaking. The aim of this study is to quantify the effect of discharge errors on parameters and performance ofuda conceptual hydrological model for discharge prediction applied to two catchments. Four error sources inuddischarge determination are considered: a combination of systematic and random measurement errorsudwithout autocorrelation; random measurement errors with autocorrelation; hysteresis in the discharge-waterudlevel relation; and effects of an outdated discharge–water level relation. Results show that systematic errorsudand an outdated discharge–water level relation have a considerable influence on model performance, whileudother error sources have a small to negligible effect. The effects of errors on parameters are large if theudeffects on model performance are large, and vice versa. Parameters controlling the water balance areudinfluenced by systematic errors, and parameters related to the shape of the hydrograph are influenced byudrandom errors. Large effects of discharge errors on model performance and parameters should be taken intoudaccount when using discharge predictions for risk assessment and decision making