Integrated Modeling For Urban Fringe Watershed Management Using Basins Model

Urban fringe watershed management often requires the use of integrated modeling procedure to evaluate the effects of land use and practices on pollutants loading to water bodies. Modeling can be expensive, time taking, and expert demanding in order to acquire input data for simulation and analysis of the results. In the most recent, the emerging technology of Geographic Information System (GIS) has provided the viable tool to generate, manipulate, and organize spatially, large amount of data of watershed and land uses. Because of limitation for Water Quality and Hydrological models to handle large amount of data, this dissertation has focused the development of integrated procedure for urban fringe watershed modeling using Arc/View GIS based PLOAD extension of BASINS watershed tool.The study has set the new approach for the integration of GIS, Best Management Practice (BMP) approach, Total Maximum Daily Loading (TMDL) procedure, Water Quality Modeling and Neural Network (NN) using PLOAD watershed model. GIS is used due to the intrinsic spatial-temporal variability of watershed, as it has provided essential an efficient method for collecting, storing and retrieving input data, while BMP's is used as cost effective approach to reduce the pollutants potential into the water system. In this study, NN model is developed and applied for the identification of nonpoint sources pollution of watershed using pattern classification. Water quality model is developed to simulate stream pollutants allocation and its integration has helped to develop TMDL modeling procedure for nonpoint and point sources of pollution. Model is further modified for temporal and spatial approximation by local Laplace Transform (LT) Finite Analytical Method (FAM) for the transportation of contaminants in the streams with higher accuracies without any significant numerical dispersion and oscillation comparing with Finite Analytical and conventional numerical Finite Difference Methods (FDM).Integrated procedure has helped the development of PLOAD model both for enhancing modeled input / output as well simulation efficiency on an annual average basis to address the study objective in Xishan urban fringe watershed of Taihu Lake Basin. On an event basis, one procedure is used to develop PLOAD model to computes the nonpoint source pollution and other procedure is used to integrate PLOAD with various modeling components of mathematical and physical nature to couple the modeling procedures under one roof to evaluate TMDL procedure. Alternative procedures are established for land management strategies integrated with BMP's utilization to control nonpoint sources pollution potential on an eventbasis. Study also has described the understanding of new concept of Total Maximum Daily Load (TMDL), defined as Loading Capacity (LC), which is calculated, as the sum of Load Allocation (LA) as nonpoint sources pollution and Waste Load Allocation (WLA) as point source pollution.About 877 km2 of agriculture and urbanized area of Xishan watershed in Taihu Lake basin is considered for study, which is also known as the economic development zone of this region. Event data is added together, where necessary, to correspond with observed data for validation. Modeling integration of various modeling techniques such as TMDL, BMP, NN, water quality modeling and their coupling has resulted the significant impact in reducing the potential pollutants from nonpoint and point sources, during the evaluation and management process of urban fringe watershed.For water quality model, Implicit Backward Difference Scheme (IBDS) is replaced with Four Point Implicit Difference Scheme (FPEDS) to modify the numerical treatment is resulted authenticated results after validation showing higher concentration of COD from 40 to 80 mg/1 in most of the rivers of study area. The method of adjusting Digital Elevation Model (DEM) by 'burning in' has resulted the threshold value of 2500ha watershed delineation in relation to county size resolution. A reduction coefficient of 75% for n...