Hey all I'm just wondering what would be acceptable for water loss in a given period of time. I'm in ontario and I'm looking about .25 inches of water a day in my 6 acre lake. Luckily we have been getting lots of rain this summer so it keeps topping up. The odd time it'll go past my overflow. We've been getting lots of warm days too, and I do haveca small trickle of water coming in from an upper pond and runoff area.
Stressless posted a response to a similar question and provided a link to US National Weather Service data. It really depends on T, humidity, wind, sun intensity, shade, etc. The data in the attachment gives evaporation rates across the US and includes some Canadian data. Many sites show rates >0.2 but as many are less.
.25” daily in 6 ac pond is 40,731 gallons or 28 gpm. A significant portion of that is due to evaporation and capillary action but appears to be a minor seep, too. My clients would trade a kidney for .25” daily loss - consider yourself fortunate - absolutely zero to be concerned with here.
On hot, dry days in the States I think it is possible to reach evaporation rates as high as 0.25" per day.
One test would be for you to set out an evaporation pan in some spot near the lake. (Probably need to put a little weld-wire over it to keep the wildlife out.) Check your actual evaporation rate. If you place it in the shade, it will probably be an underestimate. If you place it in the sun, a little overestimate. (A shallow pan will be subject to more solar heating and subsequent evaporation than your pond.)
I would use a five gallon bucket and monitor for a week. Personally I would not be concerned about 0.25" per day.
On hot, dry days in the States I think it is possible to reach evaporation rates as high as 0.25" per day.
One test would be for you to set out an evaporation pan in some spot near the lake. (Probably need to put a little weld-wire over it to keep the wildlife out.) Check your actual evaporation rate. If you place it in the shade, it will probably be an underestimate. If you place it in the sun, a little overestimate. (A shallow pan will be subject to more solar heating and subsequent evaporation than your pond.)
The other issue is plant roots drawing from the saturated soil around your lake.
I have two groundwater ponds and a groundwater creek on our farm. After the first hard freeze in the fall, the water level in my ponds AND the creek actually goes up with no rain once all of the plants in the area quit sucking massive amounts of water out of the aquifer.
You may have a smaller version of that process on your lake.
