Development of channel transmission loss function for WRF_HYDRO modeling of semi-arid regions: The case of wadi Faria, Palestine

In arid and semi-arid regions, the quantitative understanding of the processes of runoff generation and prediction of the streamflow hydrographs and their transmission to the catchment outlet are among the most basic challenges of hydrology. To address these challenges, hydrological modeling has been used to gain understanding of the hydro-logical systems and to provide the required inputs needed for sustainable water resources management. Further-more, coupling hydrological models with climatic models provides even more understanding of the influence of the climatic parameters on hydrological processes and systems, and hence on runoff generation mechanism. In this research, WRF-Hydro (the Weather Research Forecasting model coupled with the Distributed Hydrologic Modeling System) was used for streamflow forecasting in the Faria catchment. Faria (320 km2), located in the northeastern part of the West Bank, Palestine, is a gauged catchment where rainfall and streamflow data are available for more than ten years. This study aims to assess the functionality of the WRF-Hydro to predict reliable streamflow hydro-graphs at the upper part of the catchment. Additionally, a new channel loss function was incorporated into WRF-Hydro to model the amount of water lost in the ephemeral (loosing) streams of the catchment. Hence, the rainfall and streamflow data for the rainy season; 2017-2018.were utilized. Results indicate that WRF-Hydo model is well functioning, but model calibration and validation is still required to further improve the model performance.