Driving Factors of Karst Wetland Degradation from the Perspective of Hydrogeology: A Case Study in SW China

As the largest karst wetland in the low latitude region, Huixian Wetland is located in the watershed belt of Liujiang River and Lijiang River in SW China. It is of great significance on water resources regulation and ecological health maintenance for Pearl River. In recent decades, Huixian Wetland degraded and the water covering area gradually reduced. The insufficient understanding of the hydrogeological background weakened the restoration effort. In the view of karst hydrogeology, the driving factor of Huixian Wetland degradation was analyzed. Firstly, the rapid conversion of ground and surface water is one of the reasons. The short response time of groundwater to precipitation leads to the frequent occurrence of drought and waterlogging in wetland. Secondly, the underground karst pipes are narrow and easy to be blocked which resulting in the outflow of recharge water. It would reduce the storage of water resources in the core area of Huixian Wetland. Thirdly, the karst rock desertification makes a large amount of lost soil deposited in wetland. It obviously decreased the capacity of wetland regulation. With the aggravation of the rocky desertification, the sedimentation would be more intensified in the future.