Water Quality of the River Damanganga (Gujarat)

Abstract

Water quality (pH, suspended solids, chlorides, DO, BOD, reactive and total phosphorus, nitrates and boron) of River Damanganga which receives 0.2 mld of industrial waste into its fresh water zone through Pimparia River and 3.7 mld in its tidal zone was studied at 10 stations, along a 35 km stretch. Riverine flow decreased considerably in the premonsoon season and became almost negligible after April. Strong tidal effect with a water rise 5.5 m was observed near the mouth of the river during spring tides which decreased to 3.5 m during neap tides. Tidal influence was weak at upstream stations and the industrial effluent was discharged in a zone where appreciable tidal influence occurs only during spring tides. The flood and ebb currents were fairly strong. Quality of water in the discharge zone deteriorated considerably after March (DO decreasing to about 1 mg/litre). High acid content of the effluent lowered pH of water. The discharge in the fresh water zone, presently did not affect the water quality adversely. The flushing time for the estuary was calculated to be 3 days, during February. The suspended load within the estuary was high. High concentrations of phosphate at some estuarine stations were associated with the waste water discharge