Forecast City's Emergency-respond Time for Accidental Pollution in Lower Reaches of the Huainan Section of Huai River

Accidental pollution in river caused serious threat to the safety of downstream city water supply.As the accident risk increasing,emergency plan which was based on the emergencyrespond time was necessary for river-side cities.Taking the Huainan Section of Huai River for example,a hydrodynamic and water quality model was established and used to study the accidental pollution.According to different typical hydrologic conditions in different seasons the model parameters was calibrated.Then the model was used to quantitative calculate the transportation and diffusion of contaminants,and forecast the emergency respond time for accidental pollution at every water inlet.The result showed that the respond time at every water inlet for accidental pollution was significantly influenced by upper river flow conditions,and the time was obvious difference among high-flow and low-flow periods.The respond time for accidental pollution was 2.52—6.83d in low flow,and the influencing time at every water inlet by contaminated zone was nearby 3d.Accordingly,the respond time was 0.55—1.36d and the average influencing time was 0.56d in high-flow period.