Impact On Runoff Studies At The Fenhe River Reservoir Watershed Land Use Change

Land use change is an important factor that results in the change of river runoff,while the different of the land use within the basin also results in the change ofwatershed underlying surface, which changes the way of hydrologic cycle. Study onthe watershed land use variation and its influence on river runoff is of greattheoretical and practical significance in water resources planning, management,protection and the sustainable development of social economy.This paper relies on the lesson4crosshead project7of the "12th five-year"national science and technology support plan, which is " The analysis of the reasonwhy fenhe river into the yellow runoff declines"(2012BAB02B0407). By studyingthe change of the watershed land use of fenhe reservoir and its influence on fenheriver runoff, we present the reason why the fenhe river runoff changes and thecontribution rate of the land use change to the fenhe river runoff change. The mainresearch contents and results of this paper are as follows:(1) Based on the GIS technology, the situation of land use change in the basinwas analyzed through the method of area change and the analysis of space conversionmatrix of land use. The change of the weather and hydrology of fenhe reservoirwatershed was analyzed by Kendall rank correlation test method and Spearman rankcorrelation test method. The results show that:The land use situation of fenhe reservoir watershed changed obvious regularity.Among them, the area of cultivated land, land, grassland and water all have reducedwith different degree. What’s more, the trend of reducing is strengthened gradually.The area of grassland does not change obviously. The land of urban constructionincreased dramatically. In addition, the rainfall and runoff in the basin trend todecrease, and the average temperature and relative humidity trend to increase. Thewind speed, dew point temperature and solar radiation all have a different degree ofreduction.(2) The SWAT hydrology analysis model of fenhe reservoir watershed was build.The collected data of meteorological hydrology, DEM, land use and soil type was transformed through finishing. And the database of the model was established. What’smore, the fenhe reservoir watershed runoff was simulated. On this basis, through themodel parameter sensitivity analysis, model calibration and model verification, theSWAT model of fenhe reservoir watershed was established.(3) Based on the SWAT hydrological model and the water balance principle, theland use change of fenhe reservoir watershed and its influence on the distribution ofyears by using5years land use data of fenhe in1970,1990,2000,2005and2010.The land use data of fenhe reservoir watershed in1970,1990,2000,2005and2010was used as five circumstances of underlying surface over different periods. Thehydrological process in fenhe reservoir basin under the condition of five kinds of landuse scenarios was simulated respectively. The influences of the land use change onfenhe river runoff and the distribution of fenhe runoff among the years were presented.In addition, according to the simulation results of evaporation, soil moisture andrunoff in the basin in different periods and the actual data of precipitation, runoff andhuman consumption, the water quantity change of the fenhe reservoir watershed wasanalyzed. What’s more, the rate of the contribution of the land use change to fenherunoff variation was analyzed. On the basis of the results of land use change in FenheRiver Reservoir watershed,1961-1985and1985-2010are respectively the naturalperiod and the changing period for the change of underlying surface. According to themodel based on the data in the natural period, the influences of the land use changeon Fenhe River runoff are analyzed in the changing period by controlling the singlevariable (climate factor, land use, etc.).