Rainwater collection facilities to alleviate water deficit in Karst areas

Karst areas are usually water deficit due to lack of surface runoff, groundwater exceeding 120 m depth, and no obvious sign of underground streams on the ground surface. Guangxi Province karst areas in the southwestern part of China are well known for its drought conditions. It is often classified as extremely fragile karst ecosystem. Rock desertification occurs easily in this region, due mainly to less soil cover, shortage in surface water resources, and difficult vegetation recovery. Although the water problem is temporally resolved with the discovery of underground streams using water cave investigations, water supply problems still exist in these areas owing to the large-scale human activities such as mining and water pollution hazard. This study uses the SWAT (Soil and Water Assessment Tools) model to assess the hydrologic environment in karst areas located in Yaji experimental site, Guilin City, Guangxi Province, China. Water runoff condition is estimated at the study site along with surface water yield and movement. Results are also utilized to establish rainwater harvesting management schemes, to enhance water resources supply efficiency, and to minimize soil loss and sediment yield. Optimum rainwater catchment sites may be selected at high water runoff and less soil erosion locations to harvest rainwater, to reduce soil and water related disaster risks, and to alleviate intensification of rock desertification problem.