Water evaporation

[herzausstahl]

I find evaporation one of the most interesting aspects of a pond.
Low humidity = high evaporation rate no matter the temperature. -40c to +40c. Even ice evaporates.
High evaporation = temperature reduction.

That's why pond covers work so well for retaining heat in the winter - they increase the humidity which in turn reduces temperature reduction. A pond cover can be man made or natural ice.

Plants will increase evaporation when their stomata are fully open ( stomata are small openings on the plant leaf surface to aid in gas exchange). What conditions dictate fully open depends on the plant species.
It always gives me something to think about, anyways.

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I've noticed it too, 90 degrees Fahrenheit & humid equals little evaporation. 70-75 degrees low humidity equals much more.

 

[herzausstahl]

I’m sure you meant to say “dechlorinator.” I always keep some on hand in case of an emergency! We have chlorine and chloramines in our water. When I add water, I spray it in so that the chlorine can dissipate, but the chloramines are still there.

Honestly I'm gonna blame autocorrect on the iPad on that one lol catches me a lot, type in the word I mean & it changes it on me

 

[herzausstahl]

In general, yes. Math IS too hard. But I think in this case there are just too many variables to come up with a formula that works across the board. There are definitely evaporation rate tables, but how do you factor in a sunny pond vs a shady pond, or a splash waterfall vs a trickling stream. Or a pond full of plants vs one with few plants. Windy vs calm. High humidity vs low. Lots of factoring. And - math=hard.

I have waaaaaaaay too many variables to try to figure it out. I usually search for a leak when it seems abnormally excessive to me.

 

[sissy]

heat index has been over 95 and up to over 100 here for almost a month and a half and day temps. in the high 80's to high 90's .But humidity already at 7:30 am is already 99 ,,

 

[carolinaguy]

We have a natural pond near our house. It’s about 4 feet deep and an acre in size. It routinely dries up completely at least once per summer. And it will happen in a matter of days. A garden pond would slow down evaporation once the water level was too low for the pump, but it could definitely evaporate completely given the right conditions.

The challenge with using a natural pond to determine evaporation rates probably involves soil absorption, tree root draw, and the ratio of water volume versus surface area. The water temperature would need to be measured too. Tough to compare a static flow water body to a recirculating pool. Then there is the amount of rainfall and how much soil area drains to the pond. The lake behind our house is 6.5 acres and dropped at least 18 inches below the drainage level into a creek when we went 10 weeks without rain. Yes they dry up but the factors are tough to separate. Our pond loses 3/4 inch a day with leaks. It looks like 1/4 inch a day is probably evaporation.