Distribution of Nitrogen Elements and Ecological Management in the Miyun Reservoir

ZHENG Jie

doi:10.3969/j.issn.1004-7328.2025.05.003

Abstract：Based on the water quality monitoring data and related hydraulic background information of the Miyun Reservoir from 2020 to 2023,the spatiotemporal distributions of the mass concentrations of ammonia nitrogen,nitrate nitrogen,and total nitrogen concentrations were analyzed in this paper,and the variation characteristics of nitrogen elements in the reservoir were investigated.The annual changes of ammonia nitrogen,nitrate nitrogen,and total nitrogen concentrations from 2020 to 2022 showed a fluctuating increases,with a significant decrease in 2023.The peak concentrations of nitrate nitrogen and total nitrogen mostly occurred during the non-flood season,while the lowest values were generally observed during the flood season.Conversely,the peak concentrations of ammonia nitrogen mostly occurred during the flood season,while the lowest values appearing during the non-flood season.A comprehensive analysis revealed that the primary reasons for the fluctuating decline of nitrogen elements in 2023 were the effective reduction of exogenous nitrogen input due to the construction of water conservation areas upstream of the reservoir and the initial success of ecological management projects implemented by the Miyun Reservoir Management Office.These two factors were also the main measures currently used to control nitrogen increases.