The Research On Comprehensive Control Model In Small Watershed

Water is origin of life, soil is root of the survival. Water and soil resources, the basic conditions for human's survival and develop are basic resources could not be replaced. Being a developing country with large population, and water and soil resources per capita is relatively scarce, China have to feed 22% of the world population with only 7% of the world farmland. Water resource share per capita in China is only 2,200 m~3, which is equal to 32% of the world's average, it is nearly approaching to internationally accepted alert line. Water and soil resources deficiency is a primary problem we are facing in our country's development. Soil erosion is one of the main reasons that our country's water and soil resources were destroyed. At present the area of water and soil erosion in China is 3,560,000 km , which accounts for 37% of our country's territorial area. The severe water and soil erosion leads the cropland decreased, the productivity of farmland dropped, ecosystem unbalanced and flood and drought disaster frequent appeared. The sum of lost soil annually is up to 5 billion ton, which means that 66,700hm2 of tillage layer was lost, this has retard the progress of sustainable development of the agriculture. The economic loss caused by soil erosion is over 10 billion RMB every year in China, and soil erosion has become China's number one environmental problem. Therefore, it's an inevitable choice for China's sustainable development to carry on comprehensive control on water and soil erosion in unit of small watershed. The research on comprehensive control model in small watershed is a complicated systems project, it is not only a technical problem, it is also important to organize and coordinate relationship of every component in the system. We should study the problem of comprehensive control in small watershed in system thinking and analyze its present obstacles in management system and technology. In order to accelerate the progress and enhance the level of prevention and control of water and the soil erosion, we should explore and establish the new comprehensive control model in small watershed from several aspects such as legal policy, capital investment, technique support, evaluation of harness effect, role of nation, peasants and social organization, etc. It needs many subjects' support including agriculture, forestry, animal husbandry, ecology, resource science, environmental science and social science. Hence, we should further researches on the comprehensive control model of small watershed from systemic and integrated angle, especially researches on coupling rule of various elements, optimization planning on structure and objective evaluation methods should be strengthened.This paper applied principal and methods of system theory, theory of value ofresources, water and soil conservation science, ecology, ecological economics, economics, game theory and other subjects, combined specification analysis with practical analysis, qualitative analysis with quantitative analysis. Basing on the systemic analysis of the history and present situation of our comprehensive control in small watershed and some representative overseas comprehensive controlling models in small watershed, this paper probe the items of Chinese comprehensive control in small watershed such as idea, main body, rule and law system, social ethic, benefit evaluation system, capital investment, technical support, organization establishment, implementation mechanism and so on. It originally put forward the quantified estimation system of the comprehensive control in small watershed, and established the corresponding system frame within which it structured a new comprehensive control model in small watershed in accordance with Chinese situation. The new model contains the following four constituents: scientific and harmonious control idea, plural investment and financing mechanism, continually perfecting technical system, market operation and organizing mode leaded by the government. Finally, this paper combine the theory with the practice to analysis the case of Letianxi watershed in Three-Gorges reservoir area and put forward a new strategy of establishing comprehensive control model in small watershed. Through the study, putting forward new model and strategy it helps to promote comprehensive control in small watershed to realize the essential objective of "Two sustainability", namely, realization of sustainable utilization of water and soil resource and sustainable maintenance of ecological environment, through realization of "two sustainability" to support sustainable development of economic society and establish a harmonious society.