Research On Wetland Flood-control And Its Development Scheme

Based on the harmonious development principle of human and nature, the research on on wetland flood-control and its development scheme is finished by taking the wetland of the Dongting Lake for example.Based on the latest scientific achievements and historic records of multiple subjects on geological structure, archaeology, historical geography and so on, the wetland evolvement rule of Dongting Lake and the historical evolutionary process and range since the Holocene Epoch is set up, and then it is concluded that Dongting Lake will maintains the existing circumstance in a relatively long period.By the way of Great Lake Model, the flood control problems on wetland of the Dongting Lake are deeply studied in the dissertation. The study indicates that the principle problem on the wetland of Dongting Lake development is the flood problem. According to the principles with less engineering cost and smaller flood-range, and improving regional flood control capacity by adopting method of flood division and storage is reasonable.By utilizing underwater topography map with the 1:10000 scale of Dongting Lake, the topography digitalization of the lake area, and established grid system coincident with actual topographic conditions and two-dimensional hydraulics model is set up.The two-dimensional hydraulics model is also used to simulate wetland flood division process and storage in flood-storage dyke of the Dongting Lake dynamically and quantitatively. Besides flood-control benefit of dredging works is calculated by utilizing this model. The study proved the dredging works will improve flow field easement degree and reduce flood level greatly under the conditions of high flood level.On the basis of wetland evolvement rule of Dongting Lake, flood control problems, dynamic simulation of wetland flood division and storage in flood-storage dyke and some studies on resettlement policy, a new development mode for the wetland on Dongting Lake is preferred. That is to say, a new wetland development scheme with building key dyke to insure the sustainable economy and community development, flood storage in flood season and carrying out scale economy like farming and forestry in non-flood season is set up in the paper. In this way, the new development scheme not only will improve regional flood control capacity but also benefit the natural ecosystem restoration and rebuilding of wetland. And it is reasonable and feasible to meet the object of harmonious coexistence of human and nature through the developed scheme.