Effect Of Land Use And Land Cover Change On Runoff Inthe Wuyuer River Watershed

This paper mainly studies WuYuEr River Basin, adopting four years ’land-use data of 1980, 1995, 2000 and 2010, DEM data and soil data as data sources, using of geographic informational system, statistics and other research methods, employing L-THIA model to simulate and analyze land-use of catchment area in Ian station the hydrological effects of cover change analyzed the spatial variation of four phases of the area of land-use change which was based on the transfer matrix of land- use,providing the effective suggestions and exploitable plan for the rational utilization of land resources and protective the water safety of river basin. The conclusions are as follows:(1) Statistical analyzed of the WuYuEr River Basin land-use from 1980 to 1980, the results show that the cultivated land area is augment ting gradually in the whole River Basin land-use types, where as marsh wetland area is reducing and the change rate increasing steadily during this period. The area of woodland and grassland has a tendency to reduce before 2000, then recovery. The whole catchment area in Ian station variation trend similar to the whole watershed land-use. Cultivated land area is gradually increasing, marsh and wetland area is reducing, otherwise marsh wetland area change rate is less than the rate of change of marsh wetland area of the whole valley. Give a Conclusion by using transfer matrix analyzed with catchment area in Ian station: cultivated land mainly transform into marshes and forest land, forest land mainly transform into farmland, and swamp wetland mainly transform into cultivated land and forest land. The grass mainly transform into mire, cultivated land and forest land. The whole catchment area in Ian stationed change tendency is still cultivated land occupation to forest land and marsh and wetlands.(2) Experience prove that L-THIA model to the study area change and the influence of land-use on runoff simulation has good precision. Use L-THIA model to simulate the WuYuEr river basin the hydrological response of different rainfall intensity of three land-use types in 1980, 1995 and 2010. Results showed that the precipitation characteristics impact the hydrological of land-use type changing, which the Wet year is the most obvious, then the median water year and the dry year respond inconspicuous. Land-use types changing effect depth of runoff with seasonal differences, especially in the precipitation adequately summer. With the decrease of the runoff depth of absolute amount, the monthly runoff depth decreases variation amplitude.(3) Research in four typical basin shows that there are large difference in reciprocal transformation of land-use types on the influence of runoff depth, that The transformation of the wetland to cultivated land is most obvious which runoff depth decreased 63.10 mm/km2;secondly is the transformation of the cultivated land to the forest land which runoff depth decreased 34.86 mm/km2; the transformation of the Cultivated land to the residents has relatively weak influence on runoff depth which decreased 11.23 mm/km2; the transformation of the Grassland to the cultivated land produced the weakest variation of runoff depth which decreased about 0.93 mm/km2. Studies show that of land-use change has obvious effect to runoff depth, and put forward the solution.