Author(s): Amina Bensalem and Karim Haddad

Abstract: Dam construction has long been regarded as a vital tool for water resource management, hydroelectric power generation, and flood control. However, it also poses significant ecological challenges, particularly to aquatic biodiversity. This study evaluates the ecological impacts of dam construction on aquatic biodiversity, water quality, and fish migration patterns while identifying effective mitigation strategies. Field surveys were conducted across upstream, mid-reservoir, and downstream zones of selected dam-affected river systems. Biodiversity indices, including the Shannon-Weiner Index and Simpson Diversity Index, were calculated, and hydrological models (SWAT and HEC-RAS) were employed to assess flow regime changes. Radio telemetry and PIT tagging techniques monitored fish migration patterns, while water quality parameters such as dissolved oxygen (DO), temperature, nitrate, and phosphate concentrations were measured in situ.The results revealed a significant decline in biodiversity indices in mid-reservoir zones (Shannon-Weiner Index = 2.1) compared to upstream zones (3.5). Migratory fish species exhibited reduced success rates in navigating fish ladders, with only 45% achieving successful passage. Water quality parameters showed significant spatial variability, with elevated temperatures and reduced DO levels in mid-reservoir zones. Regression analysis demonstrated a strong negative correlation (R² = 0.97, p<0.05) between water temperature and biodiversity indices, highlighting thermal stratification as a key factor affecting biodiversity. Despite mitigation efforts such as fish ladders and controlled environmental flow releases, their effectiveness remained inconsistent.The study concludes that dam construction significantly disrupts aquatic ecosystems, but targeted mitigation strategies can alleviate some of these impacts. Recommendations include improved environmental flow management, advanced fish passage designs, habitat restoration, and community participation in dam management. A holistic approach integrating ecological, technological, and policy interventions is essential to balance human development with aquatic ecosystem preservation.

DOI: 10.22271/27078302.2024.v5.i2a.55

Pages: 55-60 | Views: 81 | Downloads: 22

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