Graduate Research Assistant Univerisity of Georgia, Georgia, United States
Abstract: Abstract The development of hydropower dams has rapidly increased worldwide, but the use of water for hydropower production can cause disruption to the connectivity of streams, rivers, and the ecosystems that support them. Benthic macroinvertebrates have been shown to be excellent bio-indicators for evaluating the impacts of a wide range of water pollution, climate change, and flow alteration in river ecosystems because they are very sensitive to these stressors. This study aims to assess the impact of the Trishuli 3A hydropower dam on benthic macroinvertebrates and water quality in upstream and downstream areas of the dam in two seasons, winter and spring.
The study was conducted at five sites, including one reference site (far above the dam), three disturbed sites (just above the dam, just below the dam, and a dewatered section), and a recovery site (far below the dam). The Multi-Habitat Sampling (MHS) method was used for macroinvertebrate sampling, and 60 water samples (6 replicates in each site) were collected for physico-chemical analysis. Statistical analyses, including Principal Component Analysis (PCA), Redundancy Analysis (RDA), and Two-way Analysis of Variance (ANOVA), were used to evaluate the data. The river water quality was analyzed using GRSBIOS/ASPT, and all the sites were found to belong to class I, indicating good water quality.
The results showed that the species richness of macroinvertebrates was higher in the reference sites, i.e., the upstream and downstream recovery sites, than in the disturbed sites near the dam. RDA analysis showed that Dissolved Oxygen (DO), pH, temperature, and conductivity were closely associated with benthic macroinvertebrates. PCA analysis showed that alkalinity and nitrate (NO3) were correlated with PCA1 in winter, while TDS and NH3 were correlated with PCA1 in spring. PCA2 was correlated with free CO2 in winter and with Turbidity and calcium hardness in spring.
The study highlights the need for rigorous assessment studies before implementing future hydropower projects to minimize the potential environmental impact of hydropower dams. The findings of this study can serve as a reference document for future studies and inform decision-making processes for future hydropower projects. The study also emphasizes the importance of considering the impact of hydropower dams on benthic macroinvertebrates and water quality in river ecosystems to ensure sustainable and responsible hydropower development.
Index words :- Hydropower dam, Benthic macroinvertebrates, Water quality, River ecosystems, Environmental impact, Sustainability
