The Study Of Small Watershed Landscape Function Division And Hydrological Response Assisted By LFA Method And GIS

In order to verify the applicability of the appraisal method about the landscape functions, LFA method for short, in studying areas, and at the same time using the studying ways to make comprehensive assessment, study the Caijiachuan scenery function size and combining the hydrographic observation data about Caijiachuan basin to analy the hydrographic response mechanisms of different ranks of the landscape functions in the sub-basin. The experimental investigations have been researched from july to august in 2008 and july to august in 2009 in Caijiachuan basin. The results showed that:(1) LFA method have a good application in the area, so it can become a quick and quantitative appraisal method of landscape functions for different types of vegetation and land in loess area. Utilizing the LFA method to provide the indicators of the patch area, the indicators of the landscape instruction, the indicators of the soil structural stability, the indicators of the soil structural permeability, the indicators of the soil structural nutrient circulation, we could better appraise the human influence of the landscape functions of artificial woodland and the soil performance, and the result is a match case of the physical truth.(2) According to the five indicators like patch area and so on in LFA method, the value of variables-landscape functions which comprehensively reflected the landscape functions in the studying area can be calculated by weighted sum. and this value could be quickly computed by the land use and the average slope. The theory value of the landscape function is between 0 and 69. If the value is greater, then the plaque retain function is better, the soil structural stability is more significant,the soil structural permeability is stronger, and the soil structural nutrient circulation is more active.(3) In view of the clustering functionality and the scope of the landscape functions value, the landscape functions level can be carved up to four classes:badly, normally, better and best. Using this classification, the landscape functions level of the different types of the studying area can be divided more quickly and exactly.(4) The whole landscape functions level in the Caijiachuan basin belongs to the better part, the fewer landscape feature belongs to the general level, the more little landscape feature belongs to the worse level, and only a very small landscape feature belongs to the high level. The basin should reduce the number of the common agricultural land,and apply to the forestation of the wide and large areas, but not only directed at 25 degrees above. (5) The level of watershed landscape features on watershed runoff and inter-runoff changes are significant. Landscape features mean a higher basin, can effectively increase the surface infiltration, reduce runoff, and reduced inter-basin runoff coefficient on changes in intensity. Landscape features within the basin land the size of the difference between the value of inter-month changes affect runoff coefficient. Landscape features of the basin mean little difference between the standard deviation of the value of landscape features smaller basins, inter-month changes in runoff coefficient is more gentle.