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A Semi-distributed And Parameter Self-adaptive Urban Rainfall-runoff And Pollution Modeling System

Posted on:2011-07-29Degree:MasterType:Thesis
Country:ChinaCandidate:S B LinFull Text:PDF
GTID:2131330338490418Subject:Hydraulic engineering
Abstract/Summary:PDF Full Text Request
Fast urbanization process resulted in dramatic change of urban land surface characteristics so that runoff peak of urban rain-runoff increased significantly and flow peak arrived earlier than that of natural area. For example, serious flood events occurred frequently in the Beijing, Shanghai, Shenzhen and Guangzhou city such that it brought serious threat to urban people's lives and properties. Moreover, water pollution issues are becoming serious due to mankind activities. After point source pollution has been gradually controlled in urbanization area, non-point source pollution is becoming the most important problem which is concerned by governments and researchers. In order to effectively prevent urban flooding, rainfall-runoff characteristics in highly urbanization area are desired. On the other hand, spatial and temporal characteristics of urban non-point source pollution are also required for pollution control. Therefore, it is desired to develop effective urban rainfall-runoff and nonpoint pollution model for supporting decision making on urban flood prevention and nonpoint source pollution control.Many rainfall-runoff and non-point source pollution models have been developed for natural basin. However, they are not effective in urbanization areas due to the factors affecting rainfall-runoff and nonpoint source pollution in urban areas are complex. Existing urban hydrological models have disadvantages in difficult modeling, unable dealing with hybrid urban and natural watershed, low parameters availability, hard treating drainage network, ineffective parameter calibration, and low simulation reliability.In this thesis, an urban rainfall-runoff and non-point sources pollution modeling system has been developed with characteristics of semi-distribtued and parameter self-adaptive based on TOPAZ hydrological approach and SWMM model. This system can be used for simulating rainfall runoff and nonpoint source pollution in a watershed with both natural and urban area. The parameters of hydrological and pollution models are calibrated with Genetic Algorithm(GA). The developed system contains functions of topographic data processing, basic parameters information extracting, hydrologic and pollution models parameters calibrating and verifying, model utilizing and results presenting.The developed system has been applied to the Shiyan reservoir watershed which is a fast urbanization area in the Shenzhen city. With the field monitored data, urban rainfall runoff and nonpoint pollution modes were calibrated and verified. GLUE method was used to analysis model uncertainty. The results indicated that observed results were located within range of simulation values at a confidence level of 90%. Nonpoint pollution simulation results presented that COD, TN and BOD5 had obvious characteristics of first flush at the early stages, which was affected by rainfall during and intensity. NH3-N has been washed off in a short period at the early rainfall-runoff stage.
Keywords/Search Tags:Urbanization, Semi-distributed, Parameter self-adaptive, Rainfall-runoff, Non-point source pollution
PDF Full Text Request
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