Impact Of Sand Mining On The Flood Control Project And Ecological Environment In Dawen River

River basins have long been exploited as sources of fine aggregates for building constructions. Sand is a valuable resource and a main input in the construction industry. With rapid urbanization, the demand for sand in many areas increases manifold. River sand is intensely harvested during low flow periods, which has high quality compared to other building materials. While river sand resources have the characteristics of necessary, consumed in large quantities, non-renewable in the development of national economy. Although sand mining can reduce the bed elevation and deepen channel, it is conducive to flood protection, but the reduction of river sand lead to the storage capacity of river bed disappeared, the hydraulic gradient of adjacent boundary makes groundwater level decline. When the river bed declines, some wells which be used for irrigation and drinking may be dry, and bridge foundations become unstable.In this paper, taking Dawen River as an example, the impact on flood control projects and ecological environment of sand mining is investigated. All kinds of igneous rock are distributed among the mountain area of Dawen River upstream, so the river sand is known as round, pure, hard and known, it is high quality construction grade sand. Meanwhile, the transport is facilitate, the costs of river sand mining are lower in this area, lead to the local river sand resources resources are exploited. Nowadays there are more than 200 sand plant along Dawen River in Tai'an. Although the amount of river sand mining is managed by river management department, the range, depth, methods of sand mining cannot be effectively controled because the sand mining area is broad. the indiscriminate extraction of sand are very serious under the bridge, near embankment and river floodplain, the flood control projects and ecological are greatly damaged in Dawen River, it is necessary to strengthen management and regulate sand mining activities. River sand mining make many sand pits in the riverbed Dawen River Basin, cause the steady erosion of riverbed, and a threat on both sides of the embankment; sandpile change river regime lead to the crops are destroyed; the habitats of fish and waterfowl are disturbed by the noise of sand mining boat, the vegetation are rolled by the sanding vehicle, the original ecological environment is destroyed by river sand mining. Therefore, by studying on the impact of sand mining activties of Dawen River to rational planned sand mining, and it will have greater economic, social benefits for improving the shortages of water and deterioration of ecological environment caused by sand mining, and it provides the theoretical basis of knowledge to ensure the mount of water, water quality and ecological economical management of Dongping Lake in North Water Transfer Project .This specific study as follows:1. This paper introduced the purpose and significance of the study; the study on ecological destruction of river sand mining at home and abroad; impact analysis of sand mining; the innovation , content and ideas of this paper and so on.2. This part described the overview of Dawen River; meteorological characteristics of Dawen River; sediment profiles of Dawen River; discharge site of Dawen River stations and so on.3. According to study on the sediment data of Dawen River, mainly include sediment discharge, annual sediment concentration, sediment yield, sediment transport rates, etc., summed up the impact on river channels by sand mining .4. According to search for relevant information mainly from the construction of housing and road construction to analyze the demand of sand in Shandong Province, the demand of sand in 2020 is predicted, and compared to the annual amount of sand mining, the co-ordination of supply and demand of sand and gravel in Shandong Province is analyzed.5. Analyze the situation of sand mining in Dawen River, by using the change of bed elevation and the annual sediment load to estimate the average annual amount of sand mining between Linwen Site and Daicunba Site from 1980 and 1999 , by investigating the 16 sample point in Dawen River, combined with field data and analyzed impact on flood control projects and ecological environment of sand mining in Dawen River.6. By working with the size distribution of river sand, fineness modulus, etc., combined with the fineness modulus of building sand, the river is divided into erosion zone, transition zone, the sedimentary area, and the forbidden mining area, restricted mining area, mining area can be eventually established.