<p>Spatial and seasonal changes in physicochemical parameters, affect insect community structure in a freshwater ecosystem. Aquatic insects were sampled in two reservoirs in the Tipaza region from June 2023 to May 2024. Differences in community structure were compared using diversity indices, and seven physicochemical parameters were measured following standard methods. The analysis of 744 collected individuals showed that the Kef Eddir reservoir exhibited higher evenness and biodiversity, reflecting a more balanced community with the presence of sensitive taxa such as Ephemeroptera, whereas the Boukourdane reservoir had lower evenness, with a dominance of disturbance-tolerant families, including Libellulidae and Culicidae. The order Odonata was dominant in terms of abundance in both reservoirs, supporting their high dispersal ability and ecological tolerance. In the Boukourdane reservoir, nitrate, ammonium, and total organic matter were present at higher concentrations. Redundancy analysis showed strong correlations between aquatic insects and environmental parameters in spring and summer, reflecting peak insect activity and thresholds of the measured parameters. The ecological status of the Kef Eddir reservoir reflects clean water and a healthy ecosystem, whereas the Boukourdane reservoir shows disrupted water quality, revealing anthropogenic pressure. The diversity of aquatic insects in Boukourdane is predicted to decrease if environmental degradation continues, emphasizing the need for sustainable water management to ensure clean water and sanitation.</p>