Optimizing selective withdrawal strategies to mitigate hypoxia under water-level reduction in Germany’s largest drinking water reservoir  

作　　者：Chenxi Mi Karsten Rinke Tom Shatwell 

机构地区：[1]Helmholtz Centre for Environmental Research,Department of Lake Research,Magdeburg 39114,Germany [2]College of Water Conservancy,Shenyang Agricultural University,Shenyang 110866,China

出　　处：《Journal of Environmental Sciences》2024年第12期127-139,共13页环境科学学报（英文版）

基　　金：supported by the German Research Founda-tion(DFG,grant RI 2040/4-1);the InventWater ITN(Inventive forecasting tools for adapting water quality management to a new climate)through the European Union’s Horizon 2020 research,innovation program under the Marie Skłodowska-Curie grant agreement No.956623 and UFZ Program Integra-tion Budget;Chenxi Mi acknowledges the financial support from the National Natural Science Foundation of China(No.42107060);Liaoning Provincial Doctoral Research Startup Fund Project(No.2022-BS-174);supported by the“Xingliao Talents Plan”science and technology in-novation leading talents project of Liaoning Province(No.XLYC2002054);the National Key Research and Develop-ment Program of China(NO.2022YFF1301000-4).

摘　　要：Water-level reduction frequently occurs in deep reservoirs,but its effect on dissolved oxygen concentration is not well understood.In this study we used a well-established water qual-itymodel to illustrate effects of water level dynamics on oxygen concentration in Rappbode Reservoir,Germany.We then systematically elucidated the potential of selectivewithdrawal to control hypoxia under changing water levels.Our results documented a gradual decrease of hypolimnetic oxygen concentration under decreasing water level,and hypoxia occurred when the initial level was lower than 410 m a.s.l(71 m relative to the reservoir bottom).We also suggested that changes of hypoxic region,under increasing hypolimnetic withdrawal discharge,followed a unimodal trajectory with themaximum hypoxic area projected under the discharge between 3 m^(3)/sec and 4 m^(3)/sec.Besides,our results illustrated the extent of hypoxia was most effectively inhibited if the withdrawal strategy was applied at the end of stratification with the outlet elevation at the deepest part of the reservoir.Moreover,hy-poxia can be totally avoided under a hybrid elevation withdrawal strategy using surface withdrawal during early and mid stratification,and deep withdrawal at the end of strat-ification.We further confirmed the decisive role of thermal structure in the formation of hypoxia under water-level reduction and withdrawal strategies.We believe the conclusions from this study can be applied to many deep waters in the temperate zone,and the results should guide stakeholders to mitigate negative impacts of hypoxia on aquatic ecosystems.

关 键 词：HYPOXIA Water-level reduction Hypolimnetic water withdrawal Stratification phenology Water quality simulation Sediment oxygen demand 

分 类 号：X524[环境科学与工程—环境工程]