Benefit evaluation of comprehensive control of rocky desertification in Southwest Guangxi and the coupling and coordination relationship.

Exploring the effectiveness of the pilot project on comprehensive control of rock desertification since its launch by China's government is of great significance for regional sustainable development. Jointly affected by the karst surface-underground geological structure and human activities, the natural ecological environment is fragile in southwest Guangxi, with frequent droughts and floods, severe soil erosion and rock desertification. Consequently, the socio-economic development in this region is relatively lagging behind. With the support of national policies, southwest Guangxi has been comprehensively carrying out projects of controlling rocky desertification, promoting the control of rocky desertification and poverty alleviation in a coordinated manner. According to "Thirteenth Five-Year Plan for Comprehensive Control of Rocky Desertification in Karst Areas of Guangxi Zhuang Autonomous Region", southwest Guangxi is designated as an area for the control of cluster-peak depression, in which comprehensive control of rocky desertification has been carried out in terms of building ecological barriers, protecting biodiversity, and promoting the protection and the comprehensive utilization of water and soil resources. In order to further investigate the effectiveness of controlling rocky desertification in cluster-peak depression of southwest Guangxi, this study the physical exploration. Based on the correction of the data from the borehole, the parameter of geological radar, V, is taken to be 0.060 m•ns -1 which is applicable to the study area. The study results indicate that Biyun lake belongs to the oblique tectonic basin, where leakage points and underground river pipes are mainly developed close to the axis of the Babu compound oblique, along the lithological interface of three sections of greystone and the second section of the mudstone of Jialingjiang Group. The mudstone constitutes a water separating plate of the karst leakage zone. After lake water seeps along the zone, it flows northwest, and is discharged in the end at the outlet of the Babu underground river. In addition, the leakage of Biyun lake is mainly of the karst pipeline type. The karst leakage zone is located at the measuring point of 540 m, with a 40-meter- deep of karst pipeline; therefore, the leakage section is relatively narrow, and it is feasible to plug the leakage by grouting. The drilling test results confirm the reliability of the technical method used in karst areas, which is combined by hydrogeological investigation, tracer test and physical exploration, because this method can well determine the direction of the leakage channel and the location of the leakage zone, and thus providing guidance on the leakage control of lakes or reservoirs in karst areas. [ABSTRACT FROM AUTHOR]