Impact of fly ash on channel morphology and ambient water quality of Chandrabhaga River of Eastern India

摘要

The present article intends to capture the impact of fly ash generated from Bakreswar Thermal Power Plant (BKTPP) on Chandrabhaga River of proximate location. Impacts have been captured giving emphasis on the morphological aspects of the channel and water quality standard. Chandrabhaga River (length: 26 km) of Birbhum district covers a mostly Rarh tract composed of coarse grain laterite soil. Field measurement of morphological parameters, water and soil samples collection from nine river sites and testing in laboratory reveal the following results: (1) In very proximate location of the fly ash pond, the river bed has raised up to 10-75 cm and the rate of aggradations declined downstream; (2) textural characteristics of bed materials have altered and become finer after huge influxing of fly ash; (3) leaching of finer fly ash particles in the pore space of the sand bed and consequent clogging has started which withstand the interaction between surface and subsurface flow; (4) suspended and dissolved load has increased by 62 % in comparison with the load before over spilling of fly ash from fly ash pond; (5) due to overloaded condition, more than 12,000 m(3)/year of fly ash is deposited over the river bed and it can defer the graded time of that river; (6) an analysis of physicochemical properties of the collected water samples states that some of the parameters, e.g., turbidity, TDS, BOD, COD and DO, are not only beyond drinking standard but also beyond the standard of irrigation and aquatic life, specifically fishes; (7) fly ash contamination highly reduced carp fishes on which a troop of fishermen spend their livelihood and they are now in anxiety for the viability of their livelihood.