Effects of the Check Dam System on Water Redistribution in the Chinese Loess Plateau

The objectives of this study are to evaluate the effects of the check dam system on water redistribution in a small basin in Chinese Loess Plateau by using a practical numerical method for the water budget process. Hydrological and meteorological observations were carried out in the small dam basin (0.43 km2). To quantitatively evaluate the effects of the check dam system on the water redistribution, hydrogeological modeling was applied to the check dam system in the basin. The numerical modeling was developed by kinematic wave theory for water flow. The model was verified by the numerical simulation of surface runoff discharge and groundwater level. Numerical calculation was carried out on the water budget of two cases: Case 1, no check dam (the control), and Case 2, with the check dam system in the year 2006. The model showed that the water budget of the surface runoff and groundwater flow in Case 1 was 97.3 and 2.7%, respectively. Conversely, the water budget of the runoff, evapotranspiration, infiltration, and change of water storage in Case 2 was 39.1, 49.3, 11.6, and 0%, respectively. The surface runoff in Case 2 decreased to 37.0% of that in Case 1. Compared with Case 1, two new components—evapotranspiration and infiltration—appeared in Case 2. Moreover, groundwater outflow slightly increased, and the surface runoff decreased. The study indicates that these effects of the check dam system are mainly caused by the formation of the sedimentary field. Evapotranspiration and infiltration are generated from the sedimentary field.