Abstract:The soft policy-making is a method that the experts determine the importance or the weight of each factor in a plan, then make comprehensive evaluation and the policy.‘The fundamentals of the method is comprehensive evaluation based on fuzzy maths as B=A*R, here, R is a fuzzy matrix composed by fuzzily evaluated values of each factor in the programmes A is a rank matrix composed by weights that show the important extent of each factor;B is the result from the evaluations *is an operation symbol. When we evaluate several control programmes or plans of soil loss, the first thing is to have rexperts and research workers to estimate the possibility, rationality and feasibility of these programmes,, then to choose the adoptable one through comprehensive evaluation. The evaluating of an overall plan can be done by experts and reseach workers in this way that the related land use programme, forest-grass construction programme, husbandry develop programme, capital construction on farmland programme, agricultural production programme, diverified economy programme and other single programmes，included in the olcrall plan, are evaluated and given the weights of them in the plan, the policy-making "yes" or "no" is made to the overall plan. On choosing the best one from several programmes given,at first, the memtership function can be used to transform the values of the farmland area, forest-land area, land area for livestock breeding, the cost to control the soil loss and the income from sideline production into the values between 0,0-1 .0，forming a. fuzzy matrix for evaluation. At last, the nearness of evaluated result of each programme to that of standard programme is calculated through comparing. The greater the nearness, the better the programme.

Abstract:As a non-equilibrium open certain structure and function system, the water system formed under action between and environment. In this paper the dissipation structure of geomorphological processes of a watershed is discussed. Attention is paid to the antagonistic action of force and resistance, dynamic and material condition.According to non-equilibrium thermodynamics, the principle of the minimum-maximum energy-dissipation rate is set up and proved with calculus oL viriation.

Abstract:This paper discusses the problem of the way to determine the value of beginning rain causing debris flow when sufficient observed rainfall data for the gully concerned are not available,The method of fuzzy similarity selection is applied for this purpose by making gullies as models for comparison whose value use of some debris flow of beginning rain debris flow are known. For any debris flow gully, the possible range value of beginning rain can be determined by analysing the degree causing of the of similarity models,the range of which would likely be the dangerous enveloped area of rainfall condition of would likely be the dangerous that gully.

Abstract:In the Yangtze River Valley, the water energy resources is plentiful in its upper reaches and branch streams, but specifically rare in the lower reach regions, So, Sichuan Province, located in the upper reaches of the Yangtze River, is rich in water energy resources too, but the power shortage is still severe at present. To solve the intense contradiction, we must make the following things well:first, to combine the economy development in the east with the exploitation of energy resources in the west closely in order to make them interdependent, intersupport, interpromotion and advance with same path; second, to act according to the principle of system engineering such as upper reaches is prior to lower reaches and branch streams to trunk streams, and not vice versa; third, to exploite the water energy resources on the upper reaches and branch streams in the first place to enable the old liberated, the minority nationality, the border and the poverty-stricken areas in the vast. west China to take off the poor and get the rich and to become a strategic rear; fourth, to pay close attention to build the water storage projects on the upper reaches and branch streams of the Yangtze River to impel tapping all available potentialities and renovating the present water power stations for the urgent problems of power shortage in winter in whole valley and its neighbour areas to be solved.

Abstract:We will take a major step toward realizing the national goal of quadrupling agricultural and industrial output value by the year 2000, energy industry and the means of transportation development have to give priority to others. Our country preserve abundant of coal deposits and hydro-power potential for use, energy industry development will mainly depend on coal mining and hydroelectric power. We must pay much attention to the work of soil and water conservation to reduce silt deposits of reserviors, and take precautions to prevent pollution of the environment. We should attach importance to solve problem through promotion of bettered culture level, and aware of importance of ecology science on one hand, strenthen the socialist legel system of soil and water conservation on the other in order to protect our national land resources.

Abstract:It is a problem of universality that debris flows endangered cities and towns in the mountainous region, especially in the Hongduan Mountains.In recent twenty years，the damages in different scales take place in every year, and cause heavy casualties and losses，even destroy part of a town.The reasons that the cities and towns were endangered by debris flows are directly related to the human activity, as well as the natural factors.The cities and towns destroyed by debris flow are mainly distributed in high mountains and deep valleys or along the foot of the mountain with a great difference of height. In history, the development of of cities and towns in the mountainous region was confined by the human cognitive ability to natural disasters and the developing level of production. Most of the destroyed cities and towns were built on the fan land of debris flow ravines. Despite facing the heavy and frequent disasters,up to now the prevention of debris flow as an important problem has not been ,known and solved, Since the middle of the sixties，the disasters have been more serious because the development. of the mountains and the construction of the cities and villages is quickened,the managemnt of the construction and the plan of city and town was imperfect and the prevention to the the disasters has not been carefully thought out or not be handled properly in the construction of city. The authors made an analysis to the destruction，destructive types and danger degree of debris flow ravines according to the position of city and town on the fan of debris flows，and to the relationship of the ravines and rivers, the factors of the distribution of city and town. It is of importance for planning city and town and working out the emergency measures to prevent against debris flows.

Abstract:Huaying city is a precious land with rich resources of mineral,energy and agriculture, being convenient in transportation and developed in industry and agriculture. As the resources is exploited and taken gradually, the natural ecological environment is being frequently. The main disasters often destroyed, mountain disasters occur seen are these, i, e,soil and water loss, collapsing, slop sliding, debris flow，mountain torrents and so on, which cause great loss in economy，and damage fields and houses terribly every year, threatening the safety and property of the local residents,The harness measures are to stablize the gully slope and sliding mass of the slope, to block the loosening solid material coming from branch ditches and upper reaches, to dredge the channels and protect the section for flood to come through, and to construct new channels in order to lead the mountain torrents and debris flow into predetermined section for the harmfulness to be avoided or reduced.