Abstract:

Ganjiang River Basin is the biggest basin of the Poyang Lake water system. Due to the large population density and a lot of enterprises, water environment in the Ganjiang River Basin has become increasingly serious. This study takes Ganjiang River Basin as the research object. We chose Waizhou site as a representative site, and used the Load Duration Curve method to draw the basin pollutant flow duration curve, and load duration curve, and obtain the maximum daily load of pollutants under different guarantee rate. We analyzed the change features of pollutant maximum daily load, and found that pollutant maximum daily load fluctuation during each month, season and water phase was bigger, each period of pollutant maximum daily load showed negatively skewed distribution, formulating different periods of pollutant total control is of great significance. Months average maximum daily load range for COD was 1 38006 t/d-7 42893 t/d, the strongest average daily pollutant carrying capacity was June, the weakest was December. The sequence of the strength of the pollutant carrying capacity of each season: summer > spring > autumn > winter; each season average pollutant maximum daily load ratio was: 3.08〖DK〗∶3.01〖DK〗∶1.24〖DK〗∶1. The sequence of the strength of the pollutant carrying capacity of each water phase was: wet season>level period 2> level period 1> dry season, and each water phase average pollutant maximum daily load ratio was: 386〖DK〗∶222〖DK〗∶151〖DK〗∶1. Water phase change characteristics can more intuitively reflect the pollutant maximum daily load changes, and discrimination of pollutant maximum daily load among wet season, level period, dry season was bigger. Finally,we compared the present load of Ganjiang river basin and allowable load fluxes, found that the water quality of Ganjiang river basin was better in general, COD had a part of surplus, but the present load of TP and NH3N had been close to the maximum allowable load, especially in the high flow period. It indicate that nonpoint source information of the Ganjiang river basin of NH3N and TP is larger, the regulated pollutants of Ganjiang river basin should give priority to nonpoint source, and focus on the control of NH3N and TP