Designing water-saving-ecological check dam sites by a system optimization model in a region of the loess plateau, Northwest China

Abstract

Check dams are the most widespread structures for successfully retaining water and checking erosion on the semiarid portions of China's Loess Plateau. However, in the process of check dam planning and construction, difficulties in identifying the weights of influential factors, balancing all factors and making decisions are common problems that seriously restrict rapid socioeconomic development. With the goals of determining potential check dam construction sites and holistically maximizing a projected check dam array's water resource, ecosystem and socioeconomic benefits (taking into account the water shortage and ecological fragility in semiarid areas), a water-saving-ecological check dam site optimization model (WCSOM) was developed. The WCSOM, with newly added water-saving factors, was applied to the selection of check dam sites in the Sijiagou Basin. The model showed that the ecological and the water-saving factors were the top two weights, accounting for 59.88% of the total weight. The top three influencing elements were conservation of water sources, flood prevention capacity and check dam control area, which were part of the ecological, socioeconomic and economic factors, respectively, accounting for 37.77% of the total weight. The scores of larger-scale check dam sites in the basin were generally higher, while the scores of smaller-scale sites were generally lower. The use of the WCSOM in watershed planning will allow a more efficient use of water and soil resources and greatly alleviate water crises in this semiarid area. The WCSOM can be further applied in other regions by adjusting the criterion and index hierarchies, and it can provide technical support for both the planning and rapid development of a check dam system.