The Study On The Problem Of Soil And Water Loss In Yan'an City District

Today, our society is just within the trouble of environment, resource, population and development, so it is an important task for us to deal with the relationship of environment and development in 21st century. With our country's economy developing at a continual and high speed after reform and open policy, our country's cities developed faster and faster which is nearly at a speed of 1 percent every year in these years. At the same time, city's development brought a universal and serious city soil and water loss problem, and ignoring such problem will cause severe and deep bad effects because city is a zone with dense population and wealth. So this issue has aroused our government and many experts, who think it is very important to strengthen the study on city soil and water loss for Chinese economy and city's sustainable development in 21st century, pay high attention to the city soil and water loss problem.This thesis chooses Yan'an, a river valley city in a heavy water erosion area of Loess Plateau, as a study object. In according to the city soil and water loss problem appeared during Yan'an city's development and basing on field investigation and some correlated article and data, the paper analyzed the background, type, peculiarity and bad effects of the soil and water loss in Yan'an city district, which will do benefit for decision-making department to make soil and water conservation planning and to take some protection measures.Through reviewing formerly studies in city soil and water loss in domestic and overseas, the thesis points out that classifying loss intensity grade of soil and water loss, constructing evaluation model, estimating bad effects quantitatively, researching on the concrete prevention and cure measures would be the main study content of city soil and water loss in the following years; Then, the thesis systematically analyzes Yan'an city district's erosion environment of city soil and water loss, which shows that the heavy soil and water loss in Yan'an city district has close relationship with its susceptive and brittle natural environment and intensive disturbance of man's activities to the natural environment; Later, through investigating and analyzing the type, law and peculiarity of the city soil and water loss, it is found that the soil and water loss in Yan'an city district has the trait of heavy loss intensity and various loss types; On the base of stating the impact of city soil and water loss on Yan'an city district's environment, the thesis presents a set of index system with primary classification standard to evaluate the impact of soil and water loss to the environment. At last, according the trait of Yan'an city district's soil and water loss and combining with a principle of optimize regulate and control and city's sustainable development, the paper puts forward some suggestion and thought for Yan'an city district's soil and water conservation in future.