A simulation model to assess the hydrologic perforance of the Tinau watershed, Nepal

Abstract

A physical event-based computer methodology is presented for evaluating the hydrologic performance of the Tinau watershed in Nepal. A stochastic model of the seasonal precipitation was developed and used to generate long-term daily synthetic rainfall data. Storm systems in the monsoon months of JUNE through SEPTEMBER are treated as frontal systems, and the storms of the remaining months of the year as independent thunderstorm events. A fitted-parameter conceptual model, called a generalized streamflow simulation system (GSSS), is used to simulate long baseflow recessions. The GSSS model transforms the synthetic rainfall data into daily streamflow using a soil moisture accounting process in a physically consistent manner. The computer output from the model consists of statistics and cumulative density functions for monthly, seasonal and annual discharges, maximum daily high and low flows, and consecutive days of low baseflow. The model output can be used by decision makers to meet the objectives of proper land use and development.