标题：EFFECT OF RESERVOIR’S INITIAL IMPOUNDMENT AND CLIMATIC CONDITIONS ON THE DISSOLVED OXYGEN IN DOWNSTREAM REACHES: A CASE STUDY ON XIANGJIABA AND XILUODU RESERVOIRS
摘要：Dissolved oxygen (DO) has a significant impact on aquatic ecological environment and the living conditions of fishes. Water quality, especially water temperature, reservoir discharge pattern and climatic conditions are believed to influence the changes in DO levels. A case study was carried out, considering all of the 3 conditions in the upstream of RURY (standing for National Nature Reserve for the Rare and Endemic Fishes in the Upper Reaches of the Yangtze River), which was established to protect the rare fish species in the Yangtze River. The study sites are in the downstream of the Xiangjiaba (XJB) and Xiluodu (XLD) reservoirs, which have been constructed and used for the initial impoundment. The objective of this research was to investigate the effects of abiotic conditions on the DO levels in the downstream reaches of the XJB and XLD reservoirs, and accordingly, to provide guidance on reservoirs’ operations strategies to control the DO levels and maintain a relatively healthy aquatic ecological environment for the rare and endemic fishes there. Data of DO concentration, water temperature, pH levels, as well as 14 meteorological parameters and 7 hydrological parameters are considered in statistical modeling. The analysis was conducted via the analysis of the changes of DO levels and stepwise multiple linear regression analysis. The results indicate that (1) DO concentration and saturation in all monitoring stations significantly increased after initial impoundment; (2) the super-saturation of DO occurred downstream of the XLD and XJB reservoirs after each impoundment; (3) DO concentration and saturation downstream of the XJB reservoir were significantly affected by water-discharging patterns, atmosphere pressure (particularly its maximum value) and pH levels, whereas DO concentration and saturation downstream of the XLD reservoir were more related to atmospheric parameters, such as atmospheric temperature and wind speed.
关键词：dissolved oxygen; abiotic factor; initial impoundment; stepwise multiple linear regression
