Research On Technology Of Delineating Riparian Buffer Strips’ Protection Red Line

Riparian buffer strips occur as transition area between aquatic and terrestrial ecosystems. They are a typical ecotone with many kinds of ecological functions such as stagnating runoff, depositing sediment, soil and water conservation, controlling non-point source pollution, stabilizing the banks, and providing animal habitat. In our country, due to the prominent contradiction between human and land in the period of rapid economic development, human are widening the scope and intensity of developing the riparian. Riparian ecological land has been seriously squeezed, lack of a continuous distribution of vegetation. Riparian ecosystem destruction and degradation is serious. At the same time, agricultural non-point source pollution, the indiscriminate discharge of industrial wastewater and domestic sewage both caused river health continued to decline, threatening the integrity and diversity of rivers and lakes ecosystems. In order to alleviate the contradiction between economic development and river health, delineating riparian buffer strips’ protection red line is important to protect the rivers and lakes’ ecosystem health and construct ecological security pattern.This paper considering the river ecosystem health and riparian management needs, studied riparian wetland protection line, studied riparian slope, width pattern and agricultural non-point source pollution purification efficiency’s relationship. Furthermore, taking Beijing as an example studied riparian buffer strips’ protection red line.The main contents and conclusions drawn from the research are as follows:(1) The boundaries of water plant functional types and soil moisture changes are consistent, in semi-humid and semi-arid areas may use the boundary of water plant functional types to identify wetland protection red line.The water plant functional types is used as wetland ecological feature index, soil moisture as is used as the influence factor index of wetland ecological feature. According to the spring and autumn plant seasonal differences determinate wetland boundary preliminarily, analysis of summer vegetation coverage data to determine water plant functional types’ boundary, then according to the riparian soil moisture variation gradient and spatial pattern’s boundaries determine soil moisture change boundary. Plant and soil moisture analysis results show that the spring and autumn seasonal changes boundary, water plant functional types’ boundary, riparian soil moisture the actual rate peak and riparian soil moisture spatial pattern are identical, and the same as the boundary of CCA’s different quadrat clusters. Therefore, in semi-humid and semi-arid areas may use the boundary of water plant functional types to identify wetland protection red line.(2) The simulation test of riparian filtration process of agricultural non-point source pollution show the relationship between the slope and width of riparian pattern changes and filtration efficiency, and according to fitting formula of TN/TP’s removal rate and width, determine the desired pollutants removal efficiency of the intercept test buffer strips’ protection the red line.Riparian field test results show that the slope is smaller, the better the removal efficiency of non-point source pollutant. When the other conditions are the same, the removal efficiency of underground runoff is better than the removal efficiency of surface runoff. Application of non-point source pollution removal rate variation data to generate the fitting formula of removal rate and width of TN/TP, considering the surface runoff and underground runoff removal efficiency, the buffer strips’protection red line that the removal rate of agricultural non-point source pollution reaches above 50% are located on the riparian slope from the water edge of 20 m.(3) Taking Beijing as an example, the technology of delineating riparian buffer strips’ protection red line are researched.According to the topography features, pollution characteristics and different ecological functions, taking 15° as a standard, the Beijing can be divided into mountain area and plain area. The ecological function of the mountain area riparian buffer strips is water and soil conservation. The 40° is used as a constructive standard of mountain buffer strips, with reference to the main slope in Beijing mountain area. The result from buffer width fitting formula which was invented by Xia Yujiu show that the mountain area riparian buffer strips’ protection red line is located on the riparian slope from the water edge of 58 m. The ecological function of the plain area riparian buffer strips is controlling non-point source pollution. Refer to a large number of the widths of buffer strips protection practices, the location of the plain area riparian buffer strips protection red line is located on the riparian slope from the water edge of 30 m. Then taking the upper reaches of the north canal as a demonstration plot, the riparian buffer strips’ protection red line is delineated. Finally, according to the three main protection red lines that are riparian wetland protection red line, the riparian field interception test protection red line of agricultural non-point source pollutant removal efficiency which has reached more than 50% and riparian buffer strips protection red line in the plain area, the buffer protection red lines to meet different targets and desires are delineated.