Just what is a "dew pond"?

[Eric in TN]

Can anyone tell me just what exactly is a "dew pond"?

[tkrabec]

Basically it is a pond filled by moisture in the air. There is generally a pile of rocks (thermal mass) that is cooler than the surrounding air (think de-humidifier). The air naturally (not exactly sure, but solar chimney type affect, or just wind) flows thru the rocks causing the water to condense.

-- tim

[WanderingOak]

Originally Posted by tkrabec

Basically it is a pond filled by moisture in the air. There is generally a pile of rocks (thermal mass) that is cooler than the surrounding air (think de-humidifier). The air naturally (not exactly sure, but solar chimney type affect, or just wind) flows thru the rocks causing the water to condense.

-- tim

I heard tell that the Romans used to construct them on hilltops for the use of their soldiers. There has been research on them on a much larger scale more recently. The thermal masses constructed were 2-3 stories high and were designed to provide water for an entire community. I am not sure where the research led or if the end result was practical or not.

[tkrabec]

it depends on the area you live, some places people watter their livetock, others I would imagine are not very effective, I'm considering building one here in FL.

Note: the rocks have to be stacked loosly and covered with insulation (dirt) to be most effective.

-- Tim

[Don Armstrong]

I can't see that the thermal mass would need insulation. What you need is for it to be cooler than the dewpoint for as long as possible. You definitely want it shaded during the day to stop it heating up. I can't see that it'd need insulation - that might help keep it lower in temperature, but it would then stop it from cooling quickly, and it would stop dew-laden air getting to the thermal mass.

They'd work best in air that was near the dew-point - foggy and misty at night would be good. Seems to me that sounds like a lot of otherwise-arid California.

[marvella]

eric in tn- howdy from tn! where ya at in this great state?? anywhere near rag mtn?

anybody got a link to this info?/ i think it's interesting.

so, here in the smokies, which does have lots of humidity, it would also need to be sheltered from the sun during the day?

i may just build a little one and see what happens. save trying to develop a spring to water stock.

[connie in nm]

I had never heard of this til today. Read of it on a forum - maybe this one??- and did a google search. Yep, a shallow saucer shaped bowl at top of a hill to collect water. Learn something new every day!!

[Explorer]

Originally Posted by Don Armstrong

I can't see that the thermal mass would need insulation. What you need is for it to be cooler than the dewpoint for as long as possible. You definitely want it shaded during the day to stop it heating up. I can't see that it'd need insulation - that might help keep it lower in temperature, but it would then stop it from cooling quickly, and it would stop dew-laden air getting to the thermal mass.

They'd work best in air that was near the dew-point - foggy and misty at night would be good. Seems to me that sounds like a lot of otherwise-arid California.

I agree, Don. The ones I saw is South Africa many years ago did not use any insulation. Just rock piled thirty or fourty feet high.

[Stickywitch]

It's something dogs wash thier dew claws off in.