Pond Boss
Posted By: BillLake Daily Summer Evaporation Rate - 06/23/12 05:06 AM
I've done a search here and on the internet in general, but I wanted some nw input from members here in the real world of ponds and lakes.

We are having a hot dry summer and my old lake is losing a half an inch of water per day, on average. I have a yardstick as a gauge, so I'm not just guessing.

The new lake (concerning leaks) I've started several threads about here is losing a little more water. I'm hoping this is only evaporation and not seepage. I hope we got that problem solved, but I can't tell right now.

Someone in our local Soil Conversation Service said that a pond or lake that doesn't have a creek running into it providing at least a trickle of water, loses a lot of water due to evaporation.

What evaporation rates are some of you experiencing now? Mu old lake has held water like a bathtub for decades, and I consider it to be very reliable. However, this year, it's dropping at the rate of about a half inch a day. I can only attribute that to evaporation.

I'd like to get your personal observations, esperiences, and what you are currently experiencing this summer if you are having an unusually hot and dry season for this time of year.

Also, I promised as update concerning the lake rennovation this past winter. I have not forgotten about that, and will be posting something very soon.

"Bill"
Posted By: Bluegillerkiller Re: Daily Summer Evaporation Rate - 06/23/12 05:21 AM
Mines down 12-15 inches atleast.. And I've had an algea explosion the last 2 days..
Posted By: BillLake Re: Daily Summer Evaporation Rate - 06/23/12 05:51 AM
Interesting you said that. I was out of town and checked my lakes today and one had a lot of algea. What's going on with that?
Posted By: John Monroe Re: Daily Summer Evaporation Rate - 06/23/12 08:34 AM
We are in a drought in east central Indiana and the water in my pond has dropped more at this time of year then it ever has in the last 15 years. My spiral ell grass is starting to come out of the water on bare ground as the water retreats. Since it cost a dollar a plant with shipping last year I hate to see any of it die even though it has spread well. So I transplant it by taking a long handled spade and take a shallow shovel full of ell grass and place it out in deeper water by setting the spade on the bottom and scooting the shovel back and forth. The grass slips off the shovel and settles on the bottom with no transplant shock. Thought I would mention this if anyone else has spiral ell grass in these drought conditions.
Posted By: RAH Re: Daily Summer Evaporation Rate - 06/23/12 10:42 AM
Really dry in west central Indiana also. Had a large LMB go belly up in a shallow pond yesterday along with another small one. Never understood how they survived with a maximun 5' depth which in now 3'. This was meant as a wetland but held more water than the experts at FWS said it could. A flood from a nearby stream stocked it some years back. I expect more casualties to come.
Posted By: FireIsHot Re: Daily Summer Evaporation Rate - 06/23/12 12:50 PM
The water level drop, and algae explosion is exactly what I'm dealing with here also. Glad to find out it's not just an isolated issue. I know nothing has really changed in my lake, but I've never seen the volume of algae here before.

John, if the water level comes back up, I would be curious to see if the eel grass survives. We get wild water level swings here, and I too would hate to lose plants like those.
Posted By: esshup Re: Daily Summer Evaporation Rate - 06/23/12 02:48 PM
My pond is a ground water pond, in sandy soil, so the water levels fluctuate greatly depending on the water table. I'm pumping roughly 25 gpm into the pond 24/7 and even so the pond is still dropping. Right now I'm 27" below full pool.

When the farmers are running the center pivot irrigation systems, and the well isn't running, I can drop 1" per day.....

For a current evap chart, go here
Posted By: RAH Re: Daily Summer Evaporation Rate - 06/23/12 03:07 PM
I am lucky, my big pond is down less than 12" even though we irrigate from it. It is sealed very well and has some tiles/springs to help it out.
Posted By: Bill Cody Re: Daily Summer Evaporation Rate - 06/23/12 04:27 PM
Expect at least 1/4" per day in the summer due to evaporation and water loss with a little wicking and seepage could easily be as high as 1/2"/day with the right conditions. The weather bureau calls this pan evaporation and some places monitor it.
http://www.wrcc.dri.edu/htmlfiles/westevap.final.html
Posted By: David Connor Re: Daily Summer Evaporation Rate - 06/26/12 03:59 PM
I would agree with evaporation. My 1.5 acre pond was built spring 11. And continued to gain water throughout last summer due to a good spring running into it, finally filling up completely in the fall. Now that it is filled to capacity, the spring is not keeping with evaporation and my pond is now roughly 7" or 8" low.
Posted By: liquidsquid Re: Daily Summer Evaporation Rate - 06/27/12 01:56 AM
I was researching the same question, so I am glad this came up. I lost one inch in one day, but that was when the pond top foot was at 90 degrees after a long hot spell, and then the temp and dew-point dropped with plenty of wind. I was very concerned for a leak. Now my losses are down to <1/4 inch a day now that it is cooler. Lost about 3" total from full pool with no rain in sight. It may work in my favor as I may be able to finish my dock up I could not finish last fall because the pond filled so quickly.

I have seepage on the middle of the back of the dam, but I cannot tell if it is from the pond or we covered a natural gas spring. It is FULL of gas bubbles which is somewhat common around here, but constantly wet to the point of sprouting cattails. The excavator was left scratching his head how our massive clay damn with a bulldozer width keyway could leak, so we are waiting to see what happens.

So as a test I filled a bucket with pond water so I could compare the two with the bucket next to the pond. The first inch loss paired up between the bucket and pond, but now the losses are differing. The 1/4 per day in the pond is 1/8 in the bucket. I am assuming that the bucket outer sides are dissipating solar heat without water loss so the water doesn't get as warm and the sides are blocking surface air flow. Really need an insulated bucket to better match the energy the pond receives and no bucket sides.
Posted By: esshup Re: Daily Summer Evaporation Rate - 06/27/12 04:51 AM
If the water in the bucket is much lower than the top lip, you won't see as much wind blowing across the water in the bucket too.
Posted By: Neskcafeshorts Re: Daily Summer Evaporation Rate - 09/13/19 05:05 AM
I have a pasture pond that is just under 1/2 acre in South Central Michigan. According to the National Weather Service, we have had abnormally low precipitation this summer . My pond sits out in the open field unprotected from the wind. This summer I lost 27 inches on my pond, so I learned about evaporation. In fact, According to a University of Montana Experiment station: shallow ponds(those under 17 feet deep) in the Midwest can loose up to 1 1/2 inches a day; and some parts of Arizona can loose up to 3 inches a day. I know I get excited when my pond goes down and there are plenty of people that will say you have a leak when it's simple evaporation. If you have a waterfall or some kind of water feature you can loose more. I also found out that you need at least 18" of water in your pond so your fish don't get froze out. I was suprised when my new pond did not freeze over at all last winter; and I live in Michigan! smile
Posted By: Snipe Re: Daily Summer Evaporation Rate - 09/13/19 05:58 AM
My location in Kansas is not a desert by any means but our Pan evaporation rate here is about 75"/year, April through Sept., Zero used for Oct through March so .25-.50" a day is pretty normal here, obviously higher on windy, dry days. With only 14" ave annual rainfall, a clean watershed is important and I'm not one of the lucky guys to have that so I have to supplement with well water.
Posted By: Funky Re: Daily Summer Evaporation Rate - 09/13/19 04:44 PM
I am in Mid-Michigan and the half acre pond dropped about 24 inches this summer. It is raining today and has for three days now. In those three days we have had a little over 3.5 inches of rain. It looks like a wet fall, so the pond will fill again. Normal summers here are a bit dry, but this summer after a very wet spring was very dry. Hoping for more level weather in summer!
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