Please factor in that ...

Please factor in that ECOLOGICAL BALANCE of the River Systems has been damaged by dumping of sewerage, untreated or partially treated sewerage and effluents, involuntary disposal of solid wastes with storm water flows during first few heavy rains...resulting into (a) Inceased BOD and highly reduced DO in River waters ; (b) Orbainic sludge created in the process makes the top layer of the river bottom a base for pollutants that also interfere with the natural percolation of river waters into the acquifers, (c) Planned or unplanned interventions in the River systems and its Flood plains have altered the flows --making natural flows less than the minimum flows during certain periods, thereby reducing the capacity of the river system to maintain its cross section, making silt pile up as flow velocities become less than 0.6 m/sec... and (c) desilting by the ageold practice of excavation/ removal of sand from the river beds has been drastically changed to prevent / regulate illegal mining of sand  -- So, objections to Dredging for removal of silt alongwith Slush and Pollutants along the bottom top cover is nacessary to improve the flows, reduce the pollutants, decrease the BOD .Same is much more relevant for Manmade water reservoirs/ lakes....as continuous dredging of top cover of bottom , of silt can also increase their storage capacity and increase their useful life while also improving the quality of water and acquatic life..Unscientific dredging at localised space beyond certain depths can create problems but it is avoidable.