Water, Energy and Environmental Engineering Research Unit, University of Oulu, P.O. Box 4300, FIN-90014 Oulu, Finland.
School of Environment, College of Engineering, University of Tehran, Tehran, Iran.
Sci Total Environ. 2021 Jul 10;777:146097. doi: 10.1016/j.scitotenv.2021.146097. Epub 2021 Mar 1.
Cycling of water quality constituents in lakes is affected by thermal stratification and homo-thermal conditions and other factors such as oligotrophication, eutrophication, and microbial activities. In addition, hydrological variability can cause greater differences in water residence time and cycling of constituents in man-made lakes (reservoirs) than in natural lakes. Thus, investigations are needed on vertical mixing of constituents in new impounded reservoirs, especially those constructed to supply domestic water. In this study, sampling campaigns were conducted in the Sabalan reservoir, Iran, to investigate vertical changes in constituent concentrations during the year in periods with thermal stratification and homo-thermal conditions. The results revealed incomplete mixing of constituents, even during cold months when the reservoir was homo-thermal. These conditions interacted to create a bottom-up regulated reservoir with sediment that released settled pollutants, impairing water quality in the Sabalan reservoir during both thermal stratification and homo-thermal conditions. Analysis of total nitrogen and total phosphorus concentrations revealed that the reservoir was eutrophic. External pollution loads, internal cycling of pollutants diffusing out from bottom sediments, reductions in inflow to the reservoir, and reservoir operations regulated vertical mixing and concentrations of constituents in the Sabalan reservoir throughout the year.
湖泊水质成分的循环受到热分层和同温条件以及贫营养化、富营养化和微生物活动等其他因素的影响。此外，水文变异性会导致人为湖泊（水库）中水质成分的停留时间和循环产生比天然湖泊更大的差异。因此，需要对新筑坝水库中成分的垂直混合进行研究，特别是那些为供应生活用水而建造的水库。在这项研究中，在伊朗的萨巴兰水库进行了采样活动，以调查在热分层和同温条件下一年中成分浓度的垂直变化。结果表明，即使在水库同温的寒冷月份，成分也没有完全混合。这些条件相互作用，形成了一个自下而上调节的水库，底部沉积物释放出已沉降的污染物，在热分层和同温条件下都影响了萨巴兰水库的水质。总氮和总磷浓度的分析表明，水库处于富营养化状态。外部污染负荷、底泥中扩散出的污染物的内部循环、流入水库的减少以及水库运行全年调节了萨巴兰水库中成分的垂直混合和浓度。
