How Do You Calculate River Concentration After a Discharge?

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To calculate the river concentration after a discharge, the initial conditions include a discharge of 10 MGD with a concentration of 150 mg/l into a river with an upstream flow of 20 MGD at zero concentration. The downstream flow dynamics involve a velocity of 10 mpd for 15 miles, followed by a slower velocity of 2 mpd for the next 20 miles, with a decay rate of 0.2/day affecting the concentration. Participants emphasize the importance of showing original effort in calculations before receiving assistance, as per forum policy. The final concentration at 35 miles downstream can be determined by applying these parameters and accounting for decay over the distance traveled. Engaging with the problem-solving process is crucial for effective learning and understanding.
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I have a question about hydraulic environment...i hope that u can solve the problem for me if possible. thank you very much.

belowing is the question:
A river receives a discharge of 10 MGD at a concentrattion of 150 mg/l. The river flow upstream is 20 MGD at zero concentration. For 15 mi downstream, the velocity is 10 mpd. A region of slow moving water is then encountered for next 20 mi where the velocity drops to 2 mpd. If the decay rate of the substance is 0.2/day, what is the concentration at the point 35 mi downstream from the outfall?
 
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yellow,

Please show what effort you have made towards solving this problem.
 
anybody can do the calculation for me?
 
It is against the policy here to provide solutions to homework problems unless the OP has shown original effort. So if you tell us what you've tried, we can help you along.
 
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