Study On Water And Soil Losses Dynamic Monitor In Minjiang Watershed Based On Geomatics

Water and soil losses is one of ecological environment problems in the earth, It causes the disasters of the descent of soil quality and silting of river. It has resulted in the threat to humanity's survival and the development. The traditional water and soil losses monitor needs the massive field investigation, consumes much time and is unable to satisfy the real-time monitor request of river basin soil erosion. The application of Geomatics supllys full accurate, rapid ,high credibility, audio visual dynamic information for space-time span regional soil erosion reseach and provides the powerful scientific assurance for regional ecological construction. This research based on Geomatics , employed 1986 and 2003 year TM remote sensing image and used the existing water and soil losses research in Minjiang watershed, carried out the dynamic monitor analysis to the Minjiang watershed's soil erosion condition, through remote sensing analysis of suspend sediment and estimation of watershed soil erosion model reflected the water and soil losses condition and its dynamic change in Minjiang Watershed.this region, the main conclusion are as follows :(1) This research takes the TM image as the foundation data resouse, uses the image process method and combine with the suspend sediment's spectrum characters, withdraws the Minjiang watershed's suspend sediment distribution information, provides the foundation data for relations research of water and soil losses and suspend sediment.(2) According to the Minjiang watershed's actual situation ,carrys out the algorithm research of the elements of R ,LS based on GIS and the RS to determine the factor chart, through the establishment of the vegetation coverage inverse model determined the C factor, has established the soil erosion qualitative estimation model and has provided the technical support for promptly implementing water and soil losses monitor of watershed.(3) This research through the research on Minjiang watershed's suspend sediment, finally indicates that: the Minjiang watershed's water quality is t on the decline, and passes through the 18a's evolution, the Minjiang' s water body is gradually transforming from clean water and lowly hanged sand to the middle and low suspend sediment primarily. (4) this research from the soil erosion analysize spatial variation and the intensity variation of soil erosion , the research indicates that the Minjiang watershed soil erosion area and soil erosion rate assume a drop tendency; from the corroded modulus change analysis we can see that Minjiang watershed soil erosion's intensity is on the increase trend, water and soil losses quantity is enlarging ,at present Minjiang watershed mildle soil erosion is primarily(5) the Minjiang watershed suspend sediment distribution and the soil erosion intensity has a stronger uniformity: although the watershed water and soil losses area reduces, the whole drains intensity is on the increase trend, which causes the soil erosion quantity increase, and the corresponding section of river suspend sediment density is increasing .