Ecosystem Threat Assessment Using Relative Scoring Method Analysis ? A New Methodology Approach to River Achencovil, Kerala

Threat factor assessment of river Achencovil, a major river originating from Southern Western Ghats, was carried out. The study attempted to fill the knowledge gap in the potential of using Relative Scoring Method Analysis on tropical riverine ecosystem for rapid threat assessment. Eighteen threat factors obtained through reconnaissance survey were subjected to RSMA for assessment purpose. The analysis revealed that the midstream of the river face severe threat with high impact values of 11 threat factors (Grant index value 382). Downstream segment also face commentable threat from 7 factors having maximum impact values (GI- 346) whereas upstream was the least affected (GI-81). From this study, it is revealed that midstream and downstream segment of this river is highly prone to pollution load and it is high time to formulate a management plan to rejuvenate this river and to eradicate the worst sources of contamination. The study recommends the restriction of high impact threat factors such as unscientific river bank cultivation, improper usage of agrochemicals, untreated discharge of industrial contaminants, waste disposal and sand mining to protect the river from degradation.