Tributary oscillations generated by diurnal discharge regulation in Three Gorges Reservoir
Among the major consequences of dam construction and operation are the deterioration of water quality and the increasing frequency of occurrence of harmful algae blooms in reservoirs and their tributaries. Former studies at Three Gorges Reservoir demonstrated that the Yangtze River main stream is th...
| Main Authors: | , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2020-01-01
|
| Series: | Environmental Research Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1748-9326/ab8d80 |
| _version_ | 1827869949065953280 |
|---|---|
| author | L H Long D B Ji Z Y Yang H Q Cheng Z J Yang D F Liu L Liu A Lorke |
| author_facet | L H Long D B Ji Z Y Yang H Q Cheng Z J Yang D F Liu L Liu A Lorke |
| author_sort | L H Long |
| collection | DOAJ |
| description | Among the major consequences of dam construction and operation are the deterioration of water quality and the increasing frequency of occurrence of harmful algae blooms in reservoirs and their tributaries. Former studies at Three Gorges Reservoir demonstrated that the Yangtze River main stream is the main source of nutrients and pollutants to connected tributary bays. Eutrophication and other water quality problems reported for the tributaries along Three Gorges Reservoir are likely a consequence of density-driven exchange flows. Past work has focused mainly on the influence of seasonal and daily flow regulation on exchange flows, less attention has been paid to hydrodynamic processes resulting from sub-daily discharge dynamics. High-frequency measurements of flow velocity and water level in a eutrophic tributary (Xiangxi River) of Three Gorges Reservoir revealed the persistent nature of bidirectional density currents within the bay. Superimposed on this mean flow, we observed ubiquitous flow oscillations with a period of approximately 2 h. The flow variations were associated with periodic water level fluctuations with increasing amplitude for increasing distance from the river mouth (up to ±0.1 m at a distance of 27.4 km from the river mouth). They were caused by a standing wave in the tributary bay, which was generated by rapid increase or decrease in discharge following peak-shaving operation modes at Three Gorges Dam. The high-frequency wave made up the largest contribution to the temporal variance of flow velocity in the tributary bay and represents a so far overlooked hydrodynamic feature of tributaries bays in large reservoirs. |
| first_indexed | 2024-03-12T15:51:50Z |
| format | Article |
| id | doaj.art-63e6927765ab47f498e9a2c7d59cd5c1 |
| institution | Directory Open Access Journal |
| issn | 1748-9326 |
| language | English |
| last_indexed | 2024-03-12T15:51:50Z |
| publishDate | 2020-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Environmental Research Letters |
| spelling | doaj.art-63e6927765ab47f498e9a2c7d59cd5c12023-08-09T15:08:00ZengIOP PublishingEnvironmental Research Letters1748-93262020-01-0115808401110.1088/1748-9326/ab8d80Tributary oscillations generated by diurnal discharge regulation in Three Gorges ReservoirL H Long0https://orcid.org/0000-0001-7118-0959D B Ji1Z Y Yang2H Q Cheng3Z J Yang4D F Liu5L Liu6A Lorke7Institute for Environmental Sciences, University of Koblenz-Landau 76829, Landau, Germany; College of Hydraulic and Environmental Engineering, China Three Gorges University 443002, Yichang, People’s Republic of ChinaCollege of Hydraulic and Environmental Engineering, China Three Gorges University 443002, Yichang, People’s Republic of ChinaCollege of Hydraulic and Environmental Engineering, China Three Gorges University 443002, Yichang, People’s Republic of ChinaState Key Laboratory of Estuarine and Coastal Research, East China Normal University 200062, Shanghai, People’s Republic of ChinaCollege of Hydraulic and Environmental Engineering, China Three Gorges University 443002, Yichang, People’s Republic of ChinaHubei Key Laboratory of River-lake Ecological Restoration and Algal Utilization, Hubei University of Technology 430068, Wuhan, People’s Republic of ChinaDepartment of Experimental Limnology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries 16775, Stechlin, GermanyInstitute for Environmental Sciences, University of Koblenz-Landau 76829, Landau, GermanyAmong the major consequences of dam construction and operation are the deterioration of water quality and the increasing frequency of occurrence of harmful algae blooms in reservoirs and their tributaries. Former studies at Three Gorges Reservoir demonstrated that the Yangtze River main stream is the main source of nutrients and pollutants to connected tributary bays. Eutrophication and other water quality problems reported for the tributaries along Three Gorges Reservoir are likely a consequence of density-driven exchange flows. Past work has focused mainly on the influence of seasonal and daily flow regulation on exchange flows, less attention has been paid to hydrodynamic processes resulting from sub-daily discharge dynamics. High-frequency measurements of flow velocity and water level in a eutrophic tributary (Xiangxi River) of Three Gorges Reservoir revealed the persistent nature of bidirectional density currents within the bay. Superimposed on this mean flow, we observed ubiquitous flow oscillations with a period of approximately 2 h. The flow variations were associated with periodic water level fluctuations with increasing amplitude for increasing distance from the river mouth (up to ±0.1 m at a distance of 27.4 km from the river mouth). They were caused by a standing wave in the tributary bay, which was generated by rapid increase or decrease in discharge following peak-shaving operation modes at Three Gorges Dam. The high-frequency wave made up the largest contribution to the temporal variance of flow velocity in the tributary bay and represents a so far overlooked hydrodynamic feature of tributaries bays in large reservoirs.https://doi.org/10.1088/1748-9326/ab8d80water level fluctuationsThree Gorges Reservoirdischarge regulationreservoir hydrodynamics |
| spellingShingle | L H Long D B Ji Z Y Yang H Q Cheng Z J Yang D F Liu L Liu A Lorke Tributary oscillations generated by diurnal discharge regulation in Three Gorges Reservoir Environmental Research Letters water level fluctuations Three Gorges Reservoir discharge regulation reservoir hydrodynamics |
| title | Tributary oscillations generated by diurnal discharge regulation in Three Gorges Reservoir |
| title_full | Tributary oscillations generated by diurnal discharge regulation in Three Gorges Reservoir |
| title_fullStr | Tributary oscillations generated by diurnal discharge regulation in Three Gorges Reservoir |
| title_full_unstemmed | Tributary oscillations generated by diurnal discharge regulation in Three Gorges Reservoir |
| title_short | Tributary oscillations generated by diurnal discharge regulation in Three Gorges Reservoir |
| title_sort | tributary oscillations generated by diurnal discharge regulation in three gorges reservoir |
| topic | water level fluctuations Three Gorges Reservoir discharge regulation reservoir hydrodynamics |
| url | https://doi.org/10.1088/1748-9326/ab8d80 |
| work_keys_str_mv | AT lhlong tributaryoscillationsgeneratedbydiurnaldischargeregulationinthreegorgesreservoir AT dbji tributaryoscillationsgeneratedbydiurnaldischargeregulationinthreegorgesreservoir AT zyyang tributaryoscillationsgeneratedbydiurnaldischargeregulationinthreegorgesreservoir AT hqcheng tributaryoscillationsgeneratedbydiurnaldischargeregulationinthreegorgesreservoir AT zjyang tributaryoscillationsgeneratedbydiurnaldischargeregulationinthreegorgesreservoir AT dfliu tributaryoscillationsgeneratedbydiurnaldischargeregulationinthreegorgesreservoir AT lliu tributaryoscillationsgeneratedbydiurnaldischargeregulationinthreegorgesreservoir AT alorke tributaryoscillationsgeneratedbydiurnaldischargeregulationinthreegorgesreservoir |