Benthic macroinvertebrates in bioassessment of Ramganga River, a Himalaya tributary of the Ganga basin

A study was conducted to determine the role of benthic macroinvertebrate fauna in an ecosystem health assessment of the Ramganga river, a tributary of Ganga basin. During October 2014 to September 2015, samples were collected at 8 stations (S1 to S8) from headwater to mouth. Lifting of stone (stony substratum) and sieving of substrate (sand - clay - silt soft bottom; mesh size 0.05 mm) methods were adopted to collect the invertebrate samples and preserved in 5% formalin. The total mean density of benthic macroinvertebrate community decreased from S1 to S2 and S3. However, it increased at S4 to S5 but tremendously (> 6 times) increased at S6 and further recorded a decline in mean density at S7 to S8. Trichoptera was the most abundant taxa at S1, while Diptera was abundant taxa at S2, S3, S4, S5, S7 and S8. Annelida (Naididae) was observed to be the most abundant taxa at S6. The biotic indices indicated that the water quality was good (S1), fair (S2), excellent (S3), and poor/very poor (S4 –S8). The overall Family Biotic Index value of the Ramganga river showed fair water quality.