What volume will be retained in the following retention pond case? Given: QN = 20,000 CFS, QD = 34,000 CFS, Period of retention = 90 min V = (QD - QN) x Period of retention in hours x 60 x 60

What volume will be retained in the following retention pond case? Given: QN = 20,000 CFS, QD = 34,000 CFS, Period of retention = 90 min V = (QD - QN) x Period of retention in hours x 60 x 60

• A. 75,600,000 CF
• B. 75,600,000 CFS
• C. 75,600,000 FPS
• D. cannot calculate without areas of three water levels

Answer: (A)

To determine the volume retained in the retention pond, we utilize the provided equation: V = (QD - QN) x Period of retention in hours x 60 x 60. In this scenario, QN represents the inflow rate (20,000 CFS), and QD represents the outflow rate (34,000 CFS). First, we calculate the difference between the outflow and inflow rates: QD - QN = 34,000 CFS - 20,000 CFS = 14,000 CFS. Next, we need to convert the period of retention from minutes into hours. Since the retention period is given as 90 minutes, we convert this into hours: 90 minutes = 90/60 hours = 1.5 hours. Now we substitute the values into the volume formula: V = 14,000 CFS x 1.5 hours x 60 x 60. Calculating this step-by-step: 1. 60 seconds multiplied by 60 minutes gives us 3,600 seconds in an hour. 2. So, we have: V = 14,000 CFS x 1.5 x 3600 = 14,000 C

To determine the volume retained in the retention pond, we utilize the provided equation:

V = (QD - QN) x Period of retention in hours x 60 x 60.

In this scenario, QN represents the inflow rate (20,000 CFS), and QD represents the outflow rate (34,000 CFS). First, we calculate the difference between the outflow and inflow rates:

QD - QN = 34,000 CFS - 20,000 CFS = 14,000 CFS.

Next, we need to convert the period of retention from minutes into hours. Since the retention period is given as 90 minutes, we convert this into hours:

90 minutes = 90/60 hours = 1.5 hours.

Now we substitute the values into the volume formula:

V = 14,000 CFS x 1.5 hours x 60 x 60.

Calculating this step-by-step:

1. 60 seconds multiplied by 60 minutes gives us 3,600 seconds in an hour.

2. So, we have:

V = 14,000 CFS x 1.5 x 3600 = 14,000 C