Research On Impact Of Bed Sediment Stirring To Water Quality Of Flow Discharged From A Reservoir

The heavy metal pollution in the bed sediment is an important respect of the natural waterpollution and it threatens biological existence and human health seriously. Once the environmentof water body from river and lake storehouse change,the heavy metal deposited in sed sedimentwill release to enter the water body again,influencing the water quality of flow.This text isdirected primarily to the reservoir of Feilai Gorge of north river, to carry on heavy metal pollutedcharacteristic analysis through the invesitigation of reservoir; to find out the river terms of bedsediment with different makeup and grade happening to raise; to find out the main influenceinfactor that the cadmium (Cd) releases; through simulated test then, to describe the releasecourse of the cadmium in bed sediment of reservoir adopting the second response dynamicsequation.The field investigation shows: the water quality of Feilai Gorge reservoir is better in thenormal running situation and the heavy metal Cd content meets I standard requirement ofwater of the country《ground water environment quality level》(GB3838-88). Through gradeanalysis of bed sediment, it has been shown that the media diameter of bed sediment is0.54mm, and proportion that sands of 0.18-2.0mm take up is relatively big, and sand kind isrelatively even. At the same time the raising term under different depth is different, and startvelocity of flow will increase with increasing of the depth of water. The simulated test haveconsidered these factors to influence the release of Cd, including polluted concentration of bedsediment, flow speed of river and diameter of bed sediment.The result reveals, the biggerpolluted concentration and flow speed of river is, the greater the release amount of Cd is. andwhen the mud is the thicker, the release amount of Cd has also the tendency to becomebig. Through describing the release course of the heavy metal Cd with the second responsedynamics equation finally, the result obtained reveals that the effect of describing is better. Theresult still reveals the time of the maximum of release of heavy metal is nearly the same, but themaximal release amount will increase with increasing of the velocity of flow, and the balance ofrelease will ahead with increasing of the velocity of flow.