SWAT Literature Database for Peer-Reviewed Journal Articles

Title:Development of an evapotranspiration data assimilation technique for streamflow estimates: A case study in semi-arid region 
Authors:Zhang, Y., L. Zhang, J. Hou, J. Gu and C. Huang 
Article ID:1658 
URL (non-DOI journals): 
Broad Application Category:hydrologic only 
Primary Application Category:evapotranspiration assessment 
Secondary Application Category:model comparison 
Watershed Description:10,000 km^2 Upper Heihe River, located in northwest China. 
Calibration Summary: 
Validation Summary: 
General Comments: 
Abstract:Streamflow estimates are substantially important as fresh water shortages increase in arid and semi-arid regions where evapotranspiration (ET) is a significant contribution to the water balance. In this regard, evapotranspiration data can be assimilated into a distributed hydrological model (SWAT, Soil and Water Assessment Tool) for improving streamflow estimates. The SWAT model has been widely used for streamflow estimations, but the applications combining SWAT and ET products were rare. Thus, this study aims to develop a SWAT-based evapotranspiration data assimilation system. In particular, SWAT is gridded at Hydrologic Response Unit (HRU) level to incorporate gridded ET products acquired from the remote sensing-based ETMonitor model. In the modeling case, Gridded SWAT (GSWAT) shows a good agreement of streamflow modeling with the original SWAT. Such a scant margin between them is due to the modeling domain mismatch caused by different HRU delineations. In the ET assimilation case, we carry out a synthetic data experiment to illustrate the state augmentation Direct Insertion (DI) method and a real data experiment for the upper Heihe River Basin. The results demonstrate the benefits of the ET assimilation for improving hydrologic processes representations. In the future, more remotely sensed data can be assimilated into the data assimilation system to provide more reliable hydrological predictions. 
Keywords:evapotranspiration; streamflow; data assimilation; SWAT; semi-arid