【正文】 s existing water conservancy project has quite part of engineering quality is not high, low standard design, some water engineering facilities aging, large and mediumsized irrigation engineering destroyed seriously supporting not neat, cause engineering benefit attenuation, some engineering even scrapped. Fifth, the water pollution is very serious, water environmental problems. Therefore, only ensure water resources and water conservancy projects, to guarantee the sustainable utilization of the sustainable development of national economy. Only to ensure the sustainable development of water conservancy, to ensure the economic, population, resource, environment coordinated development. Water conservancy sustainable development of sustainable development of our overall is an important part of the whole national economy and, and sustainable development of the social basis and guarantee. The 21st century China, economic and social sustainable development, success will largely depend on the sustainable utilization of water resources. Water conservancy of sustainable development is a plicated system engineering, involves many aspects of resources such as water, development, utilization, management, configuration, saving, protection, engineering use and management, water conservancy investment and construction and talent development and use, water and soil conservation, flood control and waterlogged elimination, system and mechanism, science and technology and regulations, etc. Among them, the soil and water conservation is the sustainable development of water an important ponent. 2. The present situation of Chinese soil erosion China has 356 million km2 of soil erosion, among which the soil and water loss by hydraulic erosion by 165 million km2, of the wind erosion of soil erosion 191 million km2, in the water and wind erosion area 26 million km2 in the soil erosion area water erosion, wind erosion crisscross area for. Survey shows that the nationwide soil erosion side wide, large volume, whether in a mountainous, hilly or sandstorm area, or rural, urban, coastal areas have different degrees of soil erosion problems. For example, in three gorges reservoir area of approximately 5 million total km2, involving chongqing, hubei two provinces 19 area (county, city), including chongqing for 16 area (county or city), the total area is million km2. Part of chongqing soil erosion area covers million km2 in soil erosion modulus, for 3751t/million km2 for 11481 million in erosion and t. 3. The harm of soil and water loss of water conservancy dry season, easy occurrence patterns flow reductionSoil erosion is the primary consequences to reduce dry season, the serious water is parched, with discontinuous flow, specific shown in two aspects: first, the soil 21,200,000 decrease. The gap between soil particles of soil total volume in 30 ~ 50%, gap existing space, is water is the key to keeping waterhead, with water and the soil, water storage space is lost, then the soil, thus reduce also 21,200,000 from hydrological point, enhance the years a runoff change, make the flood season water more, we watersaving less. Second, soil erosion makes terraced fields, ponds, water , reservoirs, lakes, rivers, storage capacity in deposition decreased, drop accordingly 21,200,000, also make flood water more, dry water less. Therefore, soil erosion caused easily patterns. increased surface runoff, exacerbate flooding Water and soil loss make water dry season in flood season, but reduce the opposite. Serious soil erosion areas, vegetation, and most damaged mountain soil erosion is more likely to occur. When heavy rains occurs, due to ground slope is big, the vegetation is insufficient, slope intercepting ability is bad, contain the surface soil water, make rainfall intensity lower ability than soil water infiltration rate, rain infiltration, quickly to a runoff, instantaneous shapeForm the flood process and heavy rains and floods process similar, shot up steep falls, lasted for short, intense flooding torrents of inclusion, sediment downstream of the lives and property of the people suffered heavy losses. cause river, reduce water conservancy project library siltation of benefits Because the surface soil bareness, the erosion of hydraulic, TangKu with surface runoff sediment flow of rivers, and, on the other hand, the sediment deposition in the reduced capacity of flood, weakened ability, reduce the service life of the reservoir, it is apt to cause serious breakdown of ManBa, such disasters caused rivers, on the other hand, pick up high river channels, which seriously affected flood passage ability water level rises, 1994, vent appear so often in a flow of 10 years of water level in 20 years a phenomenon. easy to set off landslides and debris flow disaster Due to damage to vegetation, runoff change, soil and geological structure affected, in a rainstorm, landslides and mudslides formed extremely easily, cause flash flood disasters. Landslides and debris flows disasters in addition to houses, roads, isin electric power munication facilities outside, will also destroy the farmland, ponds, water conservancy facilities , reservoir, etc, serious still can affect shipping, make discontinuous flow. water environment quality decline The floods, occurred frequency increases with increased, surface soil sediment forms into water, water and sediment increased increased turbidity of. Meanwhile, loss of soil organic matter and contain large amount of residual pesticides, fertilizers, and other substances, these substances with soil together, make water into water nonpoint pollution increase. The more serious soil and water loss, enter the water pollutants, the more serious water pollution。s total water flow, cannot satisfy the needs of socioeconomic development. Meanwhile, the country39。附錄1. 附圖本次設(shè)計(jì)共畫4張CAD圖，它們分別是：（1）水閘縱剖面圖一張；（2）水閘平面布置圖一張；（3）水閘細(xì)部平面圖一張；