Pond Boss Forums POND CONSTRUCTION Renovating a Pond or Lake? How much water woudl it take?

Howdy PBers - its been a while!

A friend suggested to me that I could fill my 8.5 acre lake using a solar pump/well system. How would I determine the size and volume of water required to make a dent in filling my drought ridden property? Seems like a LOT of water to me...

What's the average depth of your pond? What kind of flow rate can you expect from your well?

1 surface acre = 44,100 ft ^2
1 ft^3 = 7.48 gallons

If your pond is 8.5 acres with a depth of 1'; your pond volume would be: 44,100 x 8.5 x 1 = 374,850 ft^3
374,850 x 7.48 = 2,803,878 gallons of water.

So, for every foot of water depth to the pond, you will need to add: 2,803,878 gallons of water. Also, you will need an evaporation/water loss factor which will drive that number up by a certain percentage. That factor will depend on your geographical location and time of year.

Once you are at full pool you would only need to pump the loss factor volume / day.

Hope this helps

Hmm... Not sure about your math. Did you mean this?

8.5 acres * 44100 ft^2/acre = 374850 ft^2

374850 ft^2 * avg depth 3 ft = 1124550 ft^3 (cubic ft)
1124550 ft^3 * 7.48 gal/ft^3 = 8411634 gal

So roughly 8.4 million gallons.

that's what I get for doing math, talking on the phone, and posts on the forum. Nice catch Bocomo

A well that provides 10 gallons/min would give you 14400 gal/day, which means that you'd need more than a year and a half to fill the pond from bone dry to full pool, and that doesn't even account for any evaporative loss.

If you can get 100 gallons/min, then you could probably do it, but you'd still need 60 days.

Ok, thx - what would I plan for in evaporation on a daily basis?

It varies widely by soil type, weather, etc. Someone who has a similar pond in TX might be able to ballpark it for you, but the best way to do it is to measure it yourself.

Set a stake in the bank at the current level. Wait a few days during which there's no flow of water to the pond, then go measure the vertical drop between the two stakes. Assume no significant decrease in the surface area of the pond and just calculate the volume loss. If you get these two measurements I'll help you with the math.

Im guessing it varies between 1/8 - 1/4 inch during the summer...I'm thinking if I could find a system that woudl out-pace evaporation, it may be worth my while...

If it's only 0.25 in/day then you must have pretty good clay.

You're losing
0.25 in = 0.02083 ft
8.5 acres * 44100 ft^2/acre = 374850 ft^2
374850 ft^2 * 0.02083 ft = 7809.375 ft^3 (cubic ft)
7809.375 ft^3 * 7.48 gal/ft^3 = 58414.125 gal

So roughly 60,000 gal/day.

10 gal/min will give you 14,400 gal/day.
100 gal/min will give you 144,000 gal/day.

You'd need to pump about 40 gal/min to stay ahead of the evaporative loss.

OK, thanks Bocomo.

40 Gallons per minute is a pretty decent amount of water...with a solar system, I'd have to pump twice that since its only running 1/2 the time.

Yeah, I don't have much experience with wells, to be honest. Our water comes from the sky...the groundwater is way, way down there.

Yes, in looking at pumps, they can pull 50 gallon per hour, I need 50 gallon per minute.

This chart is by month. Click on a different month to get the evap rate. http://www.cpc.ncep.noaa.gov/soilmst/efull_frame.html

As you can see, it varies from month to month. 25.4mm in an inch.

Here in June 2012 the evaporation rate was almost 3" for the month. (70mm)