School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, 13 Yanta Road, Xi'an, Shaanxi 710055, PR China.
School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, 13 Yanta Road, Xi'an, Shaanxi 710055, PR China.
Sci Total Environ. 2015 Jul 15;521-522:27-36. doi: 10.1016/j.scitotenv.2015.03.062. Epub 2015 Mar 28.
The seasonal variation of hydrological conditions caused by shifting rainfall patterns observed in recent years has significant effects on water quality. High-volume inflows following heavy rainfall events that significantly disturb stratification lead to increased dissolved oxygen (DO) at the bottom of the reservoir, inhibiting the release of nutrients from sediments and causing a rapid reduction of algal biomass in the reservoir. However, the duration and extent of these effects depend not only on the frequency and intensity of heavy rainfall events but also on the period of thermal stratification in the reservoir. The effects of heavy rainfall events on water quality during three typical stratification periods of the reservoir were systematically investigated using extensive field data. The continuous heavy rainfall that occurred in September 2011 (stratification began to diminish) completely mixed the reservoir and produced a high concentration of DO along with a low phytoplankton concentration throughout the reservoir until stratification occurred the following year. Conversely, several days were required for anoxic conditions (in the hypolimnion) and cyanobacterial blooms to reappear after the storm runoff that occurred during the stable period of stratification (August 2012). In addition, the heavy rainfall that occurred in May 2013 accelerated the formation of an anoxic zone at the bottom of the reservoir and promoted cyanobacterial blooms due to the high nutrient input and the increased water temperature after the storm runoff ended. Water-lifting aerators (WLAs) were employed in the Shibianyu Reservoir to inhibit algal growth and to control the release of nutrients. Based on our field observations and theoretical analyses, optimized management strategies are recommended to improve water quality in the reservoir under different rainfall patterns at a reduced cost.
近年来观测到的降雨模式变化引起的水文条件季节性变化对水质有重大影响。强降雨事件后的大量流入会显著干扰分层，导致水库底部的溶解氧（DO）增加，抑制沉积物中养分的释放，并导致水库中藻类生物量的快速减少。然而，这些影响的持续时间和程度不仅取决于强降雨事件的频率和强度，还取决于水库的热分层期。利用广泛的现场数据，系统研究了强降雨事件对水库三个典型分层期水质的影响。2011 年 9 月发生的连续强降雨（分层开始减弱）完全混合了水库，导致整个水库的 DO 浓度很高，浮游植物浓度很低，直到次年分层发生。相反，在稳定分层期（2012 年 8 月）发生的风暴径流之后，缺氧条件（在湖底）和蓝藻水华需要几天时间才能重新出现。此外，2013 年 5 月发生的强降雨导致在风暴径流结束后，由于高养分输入和水温升高，水库底部形成缺氧区，并促进了蓝藻水华的形成。水提升曝气器（WLAs）被用于石板峪水库，以抑制藻类生长并控制养分的释放。基于我们的现场观察和理论分析，建议采用优化的管理策略，在不同的降雨模式下以较低的成本改善水库水质。
