Presenter
Prof. Wentai Zhang, Xinjiang Agricultural University
Co-author(s)
Mrs. Guiqing Hu, Xinjiang Agricultural University
Sub-theme
3. Building Resilience for Disaster Prevention and Mitigation
Topic
3-4. Floodwater resource management and utilization
Body
Ili Valley locates in the inland arid region of northwest China. However, occasional rainstorms characterized by short duration and high intensity there might cause serious soil and water loss both on hillslope and in gully. It is estimated that flood disasters occurred in downstream lead to averagely 364 million yuan economic loss per year from 2000 to 2016 in Ili Valley. Therefore, it is urgently needed to bring out an economic and ecological solution for utilizing the surface runoff produced by rainfall completely in suit in the hilly and low mountain area. The key issues should be addressed of this study involves: (1) to evaluate the suitability of gully for rainwater harvesting at watershed scale, and (2) to test the effect of check dams on reducing runoff and promoting vegetation rehabilitation. We selected Kulusitai river watershed of Ili Valley as the study area, and calculated spatial runoff potential by using Geographical Information System techniques as well as parameters such as topographic wetness index, normalized difference vegetation index (NDVI), slope, and land use/cover. We also surveyed 21 gullies by measuring parameters such as total gully length, main gully width, main gully depth, area of catchment, and drainage density in the study area. The relationship between runoff potential and gully development characteristics was discussed. Furthermore, we planted trees near the built check dams in one gully and monitored runoff and tree growth. Results showed that nearly 40% of Kulusitai river watershed could be divided to high runoff potential area, and gully as the water flow channel became the ideal site for storing harvested rainwater. Check dams and the harvested rainwater sustained about 80 m2 vegetation patches in the gully. This study presents an approach by combining spatial runoff potential of watershed with gully characteristics to evaluate the suitability of different types of gully for rainwater harvesting. Under the background of increasing precipitation and temperature in Ili Valley, this study emphasizes the importance of gully rainwater harvesting on reducing flood disaster risk.