Modelling Water Conservation Function Based On The InVEST Model:Case Studies In Guizhou

Water is the source of human life, and it is the basic condition of human survival, and also the basic natural resources and strategic economic resources.Water conservation is one of the important service functions of ecosystem, the ecological system retain precipitation within it through the canopy, litter, root and soil, which can not only meet the needs of the various ecological components of the system, but also can continue to provide water to the outside.Therefore, timely understanding of the dynamic changes of water conservation in regional ecosystem is the basic premise for the formulation and implementation of ecological construction and environmental protection policy, and plays irreplaceable role in the protection of regional water resources and the maintenance of ecological security.This paper took Guizhou Province, the typical Karst region as the study area,using In VEST model,combined with geographic information system(GIS) and remote sensing(RS) technology,based on the data of Landsat-8 remote sensing image, meteorological data and soil physical and chemical properties in Guizhou Province in 2010,extracting the parameters and indexes of water conservation module in In VEST model,on the basis of it, the spatial and temporal distribution pattern of water conservation in Guizhou Province in 2010 was calculated and analyzed.It established the evaluation system of water conservation importance in Karst area and evaluated the importance of water conservation function of Guizhou Province in 2010, put forward protection and utilization measures,from the perspective of the combination of planning and protection of water resources in Guizhou Province, which has important practical significance to the construction of ecological environment in Karst area.The main conclusions of the study are as follows:(1)The average annual amount of water conservation in Guizhou province in 2010 was 548.07 mm, the annual water conservation quantity was 9.6553*109mm,volume fraction was 965.53 billion m~3.(2)By introducing the method of map algebra, the spatial coupling of rainfall amount, potential evaporation, land use / cover type, soil available water content and water conservation function of Guizhou Province in 2010 was quantitatively analyzed.The results showed that the rainfall and potential evapotranspiration amount and soil effective water water level in the area of water conservation function rating scale and not in strict accordance with the more rainfall and potential evapotranspiration is small, soil available water content to be bigger or vegetation better, higher water conservation function development trend.Among them, when rainfall is 1200-1300 mm, the area of water conservation function area is the largest, which is 6994.84km~2;when the potential evapotranspiration is 1000-1050 mm, the area of high water conservation function area is the largest, which is 5483.72km~2;when the effective water content of soil <20%, the area of high water conservation function area is the largest, which is 6442.24km~2;and the area of water conservation function area was the largest in shrub land, which was 11084.43km~2.(3)The importance evaluation index system of water conservation function in Guizhou province was established, and the function of water conservation was evaluated quantitatively, and use the system to draw the importance of water conservation function in Guizhou Province in 2010 to moderate the important, accounting for 55.74% of the total area of the province,Followed by a high degree of importance, accounting for 24.51%, slightly important proportion is also larger, reaching 12.93%, the average important and extremely important area of the smallest, respectively, 3.34% and 3.48%.(4)Based on the result of Guizhou Province Water Conservation Function and importance of quantitative evaluation and of the townships in the province for water conservation type partition, combined with the situation of water resources in Guizhou Province, Guizhou Province for the development of water resources utilization and protection and puts forward the corresponding management measures and recommendations.