Gradient Analysis of Landscape Pattern Affected by Hydroelectric Station Based on Moving Window Method

Based on GIS technology and by using moving window method,We carried out gradient analysis of upstream and downstream landscape pattern before and after the construction of Manwan hydropower station.Practically,it is important to quantify the ecological effect and influential range of cascade hydropower development.The results showed that in the 30 years of 1974—2004,as distance to the dam increased the upstream and downstream landscape pattern presented different gradient change because of the construction cascade hydroelectric station.Within 0~10 km upstream from the power plant,the index of landscape fragmentation,landscape diversity and landscape richness were the largest.There was a slight decrease in all indexes within 11~30 km.Due to the construction of Xiaowan hydropower station upstream,the landscape pattern within 31~38 km upstream affected greatly.In addition,through the comparison of upstream and downstream change,it shows that the influence on landscape pattern caused by construction of Manwan hydropower station within 0~10 km in the upstream is greater than that in downstream.Although the factors resulting in landscape pattern changes of downstream outside 10 km distance is uncertain,the implementation of the policy of "Returning farmland to forest" may influence to a great extent.