Volume in Pond

[MaryJ]

1.) If given in a problem the followings:

Parcel acreage, precipitation and duration and time of concentration, how would one go about finding the amount of water captured at a certain time period.

Basically, Im trying to find a formula to find the voulume of water in a pond if I just found the total flow from the parcel over a certain time frame.

For example:

I found out that after infiltration is accounted for, a flow going into a pond is 180cfs. Assuming that 100% flows directly into the pond. Say this is coming off a 1-ac parcel that is 50% impervious.

Is it the right thing to just convert cfs found (my Flow rate)to ac-ft(volume) and thats my answer (I believe this is the correct method, but not sure)?

2.) Next, how can one easily size the pond dimension required for a particular flow rate? Would it be correct to find the dimension (L , W & h) for the pond and check if that equals the the same volume of vater found in question #1 above?

 

[sac_engineer]

1.) If given in a problem the followings:
Parcel acreage, precipitation and duration and time of concentration, how would one go about finding the amount of water captured at a certain time period.

Basically, Im trying to find a formula to find the voulume of water in a pond if I just found the total flow from the parcel over a certain time frame.

For example:

I found out that after infiltration is accounted for, a flow going into a pond is 180cfs. Assuming that 100% flows directly into the pond. Say this is coming off a 1-ac parcel that is 50% impervious.

Is it the right thing to just convert cfs found (my Flow rate)to ac-ft(volume) and thats my answer (I believe this is the correct method, but not sure)?

2.) Next, how can one easily size the pond dimension required for a particular flow rate? Would it be correct to find the dimension (L , W & h) for the pond and check if that equals the the same volume of vater found in question #1 above?

If you can send the actual problem, that would help provide some clarity in resolving your inquiry. But from what I gather, you need to calculate the volume based on a rate of flow and how long that flow will occur (i.e. rate x time = volume). There are standard hydrologic procedures used to calculate the peak flow based on rainfall intensities and runoff coefficients. Because runoff isn't constant during a storm, a quick method of calculating the required storage volume of a detention pond is to graph the runoff in relation to time and calculate the required volume from the area between the y-axis (flow rate) and the curve.

Based on my hydrology notes, most problems, if not all, require calculation of the the peak flow discharge rather than detention calculations.

Good luck!

 

[engineergurl]

I recommend waiting until the rain is over, then going and measure the depth of the water in the pond... j/k

Assuming this is a permenant BMP that you are designing, check out this website for help...

http://www.georgiastormwater.com/