Modeling study of residence time and water age in Dahuofang Reservoir in China  

作　　者：SHEN YongMing WANG JinHua ZHENG BingHui ZHEN Hong FENG Yu WANG ZaiXing YANG Xu 

机构地区：[1]State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian 116023, China [2]Chinese Research Academy of Environmental Sciences, Beijing 100012, China [3]Liaoning Academy of Environmental Sciences, Shenyang 110031, China [4]Dahuofang Reservoir Administration Bureau, Fushun 113007, China

出　　处：《Science China(Physics,Mechanics & Astronomy)》2011年第1期127-142,共16页中国科学：物理学、力学、天文学（英文版）

基　　金：supported by the National Science and Technology Major Special Project of China on Water Pollution Control and Management (Grant No.2009ZX07528-006-01);the National Natural Science Foundation of China (Grant No. 50839001)

摘　　要：Understanding the dynamics of water renewal in a reservoir is essential when the transport and fate of dissolved substances are evaluated.A three-dimensional hydrodynamic model was implemented to compute average residence time and water age in Dahuofang Reservoir in China.The model was verified for a one-year time period in 2006.A simulation reproduced intra-annual variation of mixing represented by the fall/winter mixing and the spring/summer stratification.The simulated variation of vertical thermal structures also matched observation.The spatially varying average residence times and age distribution were investigated through a series of numerical experiments using a passively dissolved and conservative tracer as a surrogate.Residence time estimations yield a broad range of values depending on the position.The average residence time for a tracer placed at the head of the reservoir under high-,mean-,and low flow conditions was found to be about 125,236 and 521 days,respectively.The age simulation reveals that the age distribution is a function of the freshwater discharge.In the vertical direction,the age of the surface layers is larger than that of the bottom layers and the age difference between the surface and bottom layers decreases further downstream.The density-induced circulation plays an important role in the circulation in the reservoir,and can generate vertical age distribution in the reservoir.These findings provide useful information for understanding the transport process in Dahuofang Reservoir that can be used to assist the water quality management of the reservoir.Understanding the dynamics of water renewal in a reservoir is essential when the transport and fate of dissolved substances are evaluated.A three-dimensional hydrodynamic model was implemented to compute average residence time and water age in Dahuofang Reservoir in China.The model was verified for a one-year time period in 2006.A simulation reproduced intra-annual variation of mixing represented by the fall/winter mixing and the spring/summer stratification.The simulated variation of vertical thermal structures also matched observation.The spatially varying average residence times and age distribution were investigated through a series of numerical experiments using a passively dissolved and conservative tracer as a surrogate.Residence time estimations yield a broad range of values depending on the position.The average residence time for a tracer placed at the head of the reservoir under high-,mean-,and low flow conditions was found to be about 125,236 and 521 days,respectively.The age simulation reveals that the age distribution is a function of the freshwater discharge.In the vertical direction,the age of the surface layers is larger than that of the bottom layers and the age difference between the surface and bottom layers decreases further downstream.The density-induced circulation plays an important role in the circulation in the reservoir,and can generate vertical age distribution in the reservoir.These findings provide useful information for understanding the transport process in Dahuofang Reservoir that can be used to assist the water quality management of the reservoir.

关 键 词：Dahuofang reservoir RESERVOIR three-dimensional model residence time age 

分 类 号：TQ325.14[化学工程—合成树脂塑料工业] X524[环境科学与工程—环境工程]