Water Flow Regulation and Scheme Optimization in the Haihe River

To improve water quality in the Haihe River, 6 cycle routes and 16 water diversion schemes were simulated, and their influence on water quality was analyzed. First, a one-dimensional hydrodynamic and water quality model of the Haihe River was established. Then, according to an orthogonal experiment, 16 cycle schemes were proposed, and an orthogonal experimental table, including 3 factors and 4 levels, was used to optimize the 16 schemes. Average pollutant concentration from Sanchakou to the Erdao Sluice served as the index for orthogonal experiments. Index values were obtained from the model and the influence of three factors on chemical oxygen demand, total nitrogen, total phosphorus, and nitrogen ammonia was evaluated by range analysis. In addition, optimal schemes to reduce pollutants in each route were also obtained. After comparing the simulated results of the optimal schemes in each route, an optimal route was obtained. A combination of the one-dimensional hydrodynamic and water quality models with orthogonal experimental design was found to provide an efficient method to simulate and optimize the schemes, thereby improving water quality by water flow regulation in plain river network regions by taking into account multiple factors such as water cycle route, the operation of sluice, and the water diversion project.