Research On Hydrological Effects Of Impervious Surface Changes In Xuzhou

The study chose Xu Zhou city as the study area. The impervious surface information was extracted based on GIS and RS technology. The study mainly analyzed the changes of impervious surface and the hydrological response to those changes in the past 30 years. The L-THIA model was applied to simulate the influence of runoff and non-point source pollution by land use changes. Meantime, a simulant indoor experiment was built to study the storage amount of the green space and the soil on rainfall runoff and runoff pollution respectively. And the potential hydrological response to the changes of impervious surface in future was evaluated based on CA-Markov model. The main conclusions are as follows.1. The study analyzes the hydrological response to the changes of impervious surface based on L-THIA model. On the basis of the validity of the model, the study analyzes the impact of runoff and non-point pollution with changes in impervious surface. The result shows that with the increase of impervious surface area of the study area, the average annual runoff showed an obvious increasing trend. The impervious rate rose from 10% in 1983 to 25% in 2013, the annual runoff proportion rose from 19% to 36%. Meanwhile, the non-point pollution also appeared an increasing trend. The rate of changes of the non-point pollution load of TN, TP and SS was 26.43%, 20.37% and 18.26% respectively.2. The study predicts the land use classification of the study area in future based on CA-Markov model and analyzes the hydrological response to the changes. Firstly, the land use classifications of 2003 and 2013 are used to predict the land use classification of 2013 and the result finds that the model is suitable for the study area. Therefore, it can predict the land use classification of 2023 with the data of 2013. Finally, the L-THIA model is used to analyze the changes of runoff and non-point pollution load with the land use classification of 2023.3. The indoor experiment finds the differences of storage amount of rainfall runoff and runoff pollution between city green space and soil in different rainfall intensity and different underlying surfaces. And the result shows that the city green space is better than the soil in reducing rainfall runoff and runoff pollution.