Features of spatial and temporal distribution of nitrogen and phosphorus in the Danjiangkou Reservoir and safeguarding measures for water quality
Yu Qihui
Lin Li
Jin Haiyang
Chen Li
Abstract：In order to safeguard water quality of the Danjiangkou Reservoir and its upstream watershed,features of spatial and temporal distribution and key indicators of total nitrogen and total phosphorus were analyzed based on monitoring data of 32 water quality monitoring sections of the Danjiangkou Reservoir from 2017 to 2023.Calculation and evaluation were conducted for different sources and contributions of nitrogen and phosphorus and risks of eutrophication and algal blooms in the reservoir.The results indicate that water quality of the Danjiangkou Reservoir is generally good,mainly classified as Class Ⅰ～Ⅱ,with stable total phosphorus concentration and fluctuating total nitrogen concentration.Total phosphorus and total nitrogen concentrations in the Hubei reservoir area are higher than those in the Henan reservoir area,with a decrease tendency from upstream to downstream.Continuous heavy rainfall occurred during the flood season in 2021,resulting in a significant increase in total phosphorus and total nitrogen concentrations.Water quality of the incoming river has been stable and improving,with the proportion of Class Ⅰ～Ⅲ gradually increasing,while the concentrations of total phosphorus and total nitrogen decrease and tend to stabilize.The main source of nitrogen and phosphorus comes from upstream watersheds,followed by inundation release from subsidence areas,but the influence of sediment release is relatively small.The Danjiangkou Reservoir is generally in a moderately nutritious state,but some water bodies exhibit eutrophication during specific seasons.Water blooms occur in the backwater areas of tributaries and reservoir bays,and the risks of eutrophication cannot be ignored.It is suggested to reinforce control of pollution sources in the upstream of the reservoir area and subsidence areas,enhance capability of water quality monitoring and early warning,scientific research on water quality safeguarding and perfection of institutional mechanisms.
Keywords：the Danjiangkou Reservoirnitrogen and phosphorus concentrationpollution loadwater quality riskeutrophication
Publication Date：2024-10-27
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：8( 59-66 )