The cumulative effects of cascade reservoirs control nitrogen and phosphorus flux: Base on biogeochemical processes

Leifang Li; Lei Chen; Shibo Chen; Yuhan Zhang; Yanzhe Xu; Xiaosha Zhi; Xinyi Meng; Zhenyao Shen; Yong Liu; Dawen Yang; Lihua Tang

doi:10.1016/j.watres.2024.121177

The cumulative effects of cascade reservoirs control nitrogen and phosphorus flux: Base on biogeochemical processes

Water Res. 2024 Mar 15:252:121177. doi: 10.1016/j.watres.2024.121177. Epub 2024 Jan 22.

Authors

Leifang Li¹, Lei Chen², Shibo Chen³, Yuhan Zhang³, Yanzhe Xu³, Xiaosha Zhi³, Xinyi Meng³, Zhenyao Shen⁴, Yong Liu⁵, Dawen Yang⁶, Lihua Tang⁶

Affiliations

¹ School of Environment, Beijing Normal University, Beijing 100875, China; Department of Hydraulic Engineering, Tsinghua University, Beijing 100084, China.
² School of Environment, Beijing Normal University, Beijing 100875, China; State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China. Electronic address: chenlei1982bnu@bnu.edu.
³ School of Environment, Beijing Normal University, Beijing 100875, China; State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China.
⁴ School of Environment, Beijing Normal University, Beijing 100875, China; State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China; Key Laboratory of Hydrology and Sediment Science of Ministry of Education, Beijing 100875, China.
⁵ State Environmental Protection Key Laboratory of All Materials Flux in River Ecosystems, College of Environment science and Engineering, Peking University, Beijing 100871, China.
⁶ Department of Hydraulic Engineering, Tsinghua University, Beijing 100084, China.

PMID: 38290240
DOI: 10.1016/j.watres.2024.121177

Abstract

The reservoir serves as a water source, a flood control structure, a navigational aid, and also impacts the downstream ecosystem as well as the reservoir zone. However, debate exists about effectiveness of cascade reservoirs in controlling the transportation of nutrients, particularly in the Yangtze River basin, which has been significantly affected by reservoir development. This research develops a new model X-NPSEM (X with Nitrogen and Phosphorus Steady-state Reservoir Model) based on biogeochemical processes of nitrogen and phosphorus reaction for investigating the dynamic storage capacity of cascade reservoirs at both reservoir- and watershed scales. Then the cumulative effects of cascade reservoirs and the related mechanism were investigated in Fujiang watershed, China. Based on the results, cascade reservoirs retained 16.3 % of nitrogen fluxes and 37.6 % of phosphorus fluxes annually. Downstream reservoirs have higher retention rates of phosphorus (0.48/d) compared to upstream reservoirs (0.10/d), mainly due to inflow sediment. Nitrogen retention rates show seasonal variations: wet season (0.21/d) and dry season (0.17/d). These fluctuations in nitrogen retention are primarily influenced by changes in temperature rather than other factors such as operation period, nitrogen and phosphorus concentration, or the nitrogen/phosphorus ratio. In upstream, the concentration of sediment entering the reservoir plays a decisive role in the transformation of P retention from sink to source. The X-NPSRM coupler model could be used for global reservoir operation and watershed management.

Keywords: Biogeochemical reaction processes; Cascade reservoirs; Cumulative effects; Nitrogen; Phosphorus; Retention rate; Yangtze river.

MeSH terms

China
Ecosystem
Environmental Monitoring
Nitrogen / analysis
Phosphorus* / analysis
Water Pollutants, Chemical* / analysis

Substances

Phosphorus
Nitrogen
Water Pollutants, Chemical