The simulation of water quality control of Fengping section in Mangshi River

Abstract

The assessment of water quality is mainly based on Environmental Quality Standards for Surface Water (GB3838-2002), which divided surface water into five classes (Class I to Class V) according to its purpose for use and protection target. In April 2015, the State Council issued an Action Plan for the Prevention and Control of Water Pollution, which is a law formulated to effectively increase the prevention and control of water pollution and ensure national water safety. In 2016, the Yunnan Provincial People’s Government and the Dehong Prefecture People’s Government successively proposed work plans for the prevention and control of water pollution, requiring the Fengping Section (State Control) in Mangshi River to reach Class III of surface water by 2020. But the current water quality fluctuates between Class III and V. Based on the current status of water quality and pollution sources, the paper uses HD (hydrodynamic model) and AD (hydrodynamics advection diffusion model) in MIKE 21 FM model to establish the two-dimensional water quality model to simulate the distribution characteristic of different water quality parameters, which are Biochemical Oxygen Demand (BOD5), Total Phosphorus (TP), Ammonium Nitrogen (NH3-N). The conclusion is that reduction targets of BOD5, TP and NH3-N are namely 40%, 30% and 10% to ensure water quality, which guides the formulation of pollutant emission reduction plans more scientifically.