Bioassessment of water quality in the upland streams of lesser Himalaya, Uttarakhand, India

Low-order streams are vital sources of clean drinking water, irrigation, and habitats for aquatic life. This study was conducted in three second-order streams in the Badiyar Gad sub-basin of the Lesser Himalaya to assess water quality, diversity of macroinvertebrates, and the relevance of the Biological Monitoring Working Party (BMWP) and Average Score Per Taxon (ASPT). Monthly samples were collected for the physicochemical and biotic parameters of the three second-order streams from January to December 2019. Standard metrics (Shannon-Wiener Diversity Index, Margalef Diversity Index, Simpson’s Index, BMWP, and ASPT score system) were applied to assess the water quality and benthic macroinvertebrate diversity. 49 benthic macroinvertebrate taxa belonging to 36 families and 10 orders were identified from three different second-order streams of the lesser Himalaya. Class Insecta was the most abundant group, including orders Ephemeroptera (9 taxa), Diptera (11 taxa), Hemiptera (1 taxon), Trichoptera (12 taxa), Coleoptera (6 taxa), Odonata (2 taxa), Plecoptera (5 taxa), and Lepidoptera (1 taxon). However, the other species belonging to Decapoda (1) and Gastropoda (1) were also present. The BMWP score ranged from 178 to 226 for S1 and S2, respectively. ASPT values were computed as maximum (7.33) at S3 and minimum (7.06) at S2. The quality of these lesser Himalayan streams was classified as class I based on calculated biotic indices (BMWP and ASPT) and physiochemical data. The purity of these water bodies should be maintained by proper conservation and management so that these water bodies may serve as a perpetual source of clean drinking water and a treasure of aquatic biodiversity.