| Vegatation is an important factor to influence soil erosion, Discussion on water and sandcontrol benefits of vegetation can reflect the important effection in soil and waterconservation measures, soil and water conservation measures can be collocated reasonably,the basin soil erosion can also be reduced effectively. In this paper, we put the Huangfuchuanwatershed as the research object, based on TM images, TUD-Basin and the results of researchhave been made, obtaining vegetation coverage and changes in different years in the basinand combining with the rainfall data to analys the benefits of water and sediment reduction ofvegetation measures. Main research results are as follows:（1）Vegetation coverage increased significantly since80s to90s in the last century inHuangfuchuan basin. The whole watershed vegetation coverage area was about772squarekilometers in the late1980s, the average vegetation coverage was23.8%; The vegetationcoverage area was1262square kilometers in the late1990s, the average vegetation coveragewas31.2%. Compared with the late1980s, the average vegetation coverage in the late1990sincreased31.2%, the area increased was241square kilometers.（2）The simulation results of the runoff and sediment production based on theTUD-Basin in Huangfuchuan basin accord with actual, and can be used for simulating theprocess of the runoff and sediment yield in basin. In model calibration period（1981~1983）and model validation period（1984~1986）, except that the fitting degree of flow and sedimentis poor in1986and the relative error of sediment simulation is more than30%, the relativeerror of runoff simulation are all less than30%, the simulation coefficient of runoff andsediment production are all close to0.60or greater or equal to0.60.（3）Compared with the late1980s, the effection of water and sediment reduction of thevegetation measures was not significant in the late1990s in Huangfuchuan basin, thepercentage of water and sediment reduction was lower, it suggested that the ecologicalenvironment still need to be improved. The average water reduction of vegetation measures was0.15billion cubic meters, and the average sediment reduction was0.04billion tons; Thevegetation area increased1square kilometers, the water would be reduced6.22thousands ofcubic meters and the sand would be reduced1.66thousands of tons. The benefit of waterreduction was6.22, the benefit of sand reduction was6.05, the benefit of water reduction wasmore than sand reduction; Compared with the two vegetation conditions, when vegetationmeasures reduced one hundred million tons of sand, the water reduction was about4billioncubic meters, the ratio of water and sand reduction was lower. |
