Study On Water Quantity And Quality Integrated Regulation Of Coastal Plain River Network

Coastal plains area which has flat terrain,developed river system,crisscross watercourse,complex level of the main tributary and more to form a circular river network with reciprocating flow direction is generally on the verge of the sea that makes flood be affected by tide.Coupled with numerous water conservancy facilities,this series of factors are caused the water quantity and quality process of the coastal plain river network is extremely complex.In this paper,the study area,YAO northwest coastal plain of YUYAO City,which has the typical water features of the coastal river network,not only has many dams and pumps but also accompanied with serious water pollution.This paper relying on the "National Natural Science Foundation" project researches dispatching water quantity and quality simulation of the study area through dams and pumps to provide constructive suggestions for flood treatment,water pollution prevention and control scheme as to enhance water security in the study area.In this paper,the HEC-RAS application software is applied to build a reasonable generalization of the river network and establish the hydrodynamic-water quality model in the study area based on the research achievements of the scholars and verify the accuracy and reliability of the model.A variety of dam scheduling scenes were designed to study the change rule of water quantity and quality to provide a strong support and basis for water quality improvement program.The main conclusions are as follows:1)Establishing a one-dimensional hydrodynamic model by HEC-RAS software.Analyzing the sensitivity of the river roughess and boundary conditions to the hydrodynamic model,verifying them by the measured hydrological data.Then comparing the simulation results with the measured data and the simulation results established simultaneously of MIKE 11 to verify the accuracy and reliability.Then designing different water flow patten of tyical inter-area waterlogging schemes,the model lateral inflow is used to calculate the hydraulic characteristics of river networks under different inflow scenarios.2)Establishing a one-dimensional water quality model by HEC-RAS software.According to the characteristics of water quality and quantity of the northwestern Yao River network,establishing the model of hydrodynamics-water quality in YAO northwest coastal plain,analyzing the sensitivity of water quality parameters and boundary conditions to the water quality model and then verifying them by the measured water quality data.Using the model to study the five pollutants concentration DO,BOD5,NH3-N,TP and TN in YAO northwest coastal plain,the transport and diffusion of the concentration value along the river network,the values of simulation were compared with the measured data and the simulation results of MIKE11 to verify the accuracy and reliability.The results show that the model is reasonable in calculation accuracy and good in reliability.3)Studying the dams joint control technology in YAO northwest water network.Analyzing the operation system and rules of regional dams,and designing five different dams and pumps scheduling scenes to simulate the water quality of the study area,the results show that the dams and pumps scheduling greatly enhances the water quality.Designing different typical point source pollutant scenarios,then analysing the change rule of the path diffusion and impact about source point pollution while the movement of water changes whether there is the side-inflow.The research results can provide technical advice to the water pollution control scheme and the water security in YAO northwest coastal water body.