BIOINDICATOR BASED WATER QUALITY ASSESSMENT OF WARBO AND DABO STREAMS IN AWASH CATCHMENT, DENDI WOREDA, ETHIOIPA

The increasing impact of human activities on the freshwater bodies of Ethiopia calls for efficient and cost-effective method for water quality and ecological health assessment. In Ethiopia, river water quality monitoring totally depends on conventional method using physicochemical analysis for streams and rivers. Increasing anthropogenic pressure on water bodies-initiated researchers to develop holistic water quality assessment methods for the country. So the present study was aimed at assessing the water quality of Warbo and Dabo streams using macroinvertebrates as biological indicators. The status of water quality was assessed in terms of presence or absence of indicator organisms in relation to physicochemical parameters. Hilsenhoff Family-level Biotic Index (H-FBI) results have shown that the site 6 had relatively higher value (6.5) followed by site 5 (5.8). The site 1 recorded least H-FBI value which accounts for 3.2 followed by site 4 (3.74). For Ethiopian Biological Score Index (ETHbios index), highest score was recorded at site 3 (120) followed by site site 4 (102) while the lowest score was obtained for the site 6 and site 1 which accounts for 54 and 57 respectively. The Average Score Per Taxon (ASPT) value was comparatively higher for sites 1 (6.67) and site 3 (6.31) than other sites. Principal components analysis of physicochemical variables showed wide variation among the study sites. Axis 1 and axis 2 of the Principle Component Analysis (PCA) explained 97.5 % of the total variance regarding the sites versus physicochemical association, where the first axis and second axis contributed 73.04% and 24.56% to the variation, respectively. Results of Pearson correlation reaveled that there exists significant relation between variuos pollutant parameters.