Department of Geography, University of Alabama, Tuscaloosa, AL, 35487, USA.
Department of Zoology and Environmental Management, University of Kelaniya, Kelaniya, Sri Lanka.
Sci Rep. 2021 Jan 12;11(1):546. doi: 10.1038/s41598-020-79576-5.
Our study focused on quantifying the alterations of streamflow at a weir site due to the construction of a mini-hydropower plant in the Gurugoda Oya (Sri Lanka), and evaluating the spatial responses of benthic macroinvertebrates to altered flow regime. The HEC-HMS 3.5 model was applied to the Gurugoda Oya sub-catchment to generate streamflows for the time period 1991-2013. Pre-weir flows were compared to post-weir flows with 32 Indicators of Hydrologic Alteration using the range of variability approach (RVA). Concurrently, six study sites were established upstream and downstream of the weir, and benthic macroinvertebrates were sampled monthly from May to November 2013 (during the wet season). The key water physico-chemical parameters were also determined. RVA analysis showed that environmental flow was not maintained below the weir. The mean rate of non-attainment was ~ 45% suggesting a moderate level of hydrologic alteration. Benthic macroinvertebrate communities significantly differed between the study sites located above and below the weir, with a richness reduction due to water diversion. The spatial distribution of zoobenthic fauna was governed by water depth, dissolved oxygen content and volume flow rate. Our work provides first evidence on the effects of small hydropower on river ecosystem in a largely understudied region. Studies like this are important to setting-up adequate e-flows.
我们的研究重点是量化由于在斯里兰卡古鲁戈达河上建造小型水电站而导致堰址处的径流量变化，并评估底栖大型无脊椎动物对改变的水流状况的空间响应。我们应用 HEC-HMS 3.5 模型来模拟古鲁戈达河流域的子流域，以生成 1991 年至 2013 年期间的流量数据。使用变异性范围方法（RVA），将堰前流量与堰后流量进行了比较，共使用了 32 个水文变化指标。同时，在堰的上下游建立了六个研究点，并于 2013 年 5 月至 11 月（雨季期间）每月对底栖大型无脊椎动物进行采样。还确定了关键的水物理化学参数。RVA 分析表明，环境流量在堰以下没有得到维持。未达标率平均约为 45%，表明水文变化程度为中等。位于堰上下游的研究点的底栖大型无脊椎动物群落存在显著差异，由于引水导致生物多样性减少。底栖动物区系的空间分布受水深、溶解氧含量和体积流量的控制。我们的工作首次提供了关于小型水电站对该地区河流生态系统影响的证据。像这样的研究对于制定适当的生态流量非常重要。
