Water loss caused by net

[Becky]

We've been having some problems with our pond recently, and now that we've figured it out I thought I'd share it here!

Over the past few weeks we've had a lot of rain here in the UK, but weirdly we kept seeing dramatic water loss in our pond. Some mornings we would look out and see that almost half of the water had gone. In the end we thought that we had a leak, which was quite concerning as it would mean disassembling the pond to fix it. We were regularly filling up the pond from our water butt, but it was getting through so much that we couldn't keep up - despite all the rain. We have had drops in the water level before, but I always thought it was due to evaporation as the drop was not at a steady rate.

A few days ago we took out the water iris plants and took off the net to see if we could spy any damage to the liner... we left the pond like that after topping it up, and the next day saw that the water level had not dropped... interesting. We put the plants back in, and the next day it was still fine...

Turns out that the problems were caused by the net!

Link to the topic where Ian made the net: https://www.gardenpondforum.com/threads/rubberizeit-for-ponds.15687/

Our fountain comes up through the middle of the net, and so it would appear that some of the water was evaporating off the net instead of dropping back into the pond.

I'm just so surprised that such a large amount of water could be lost due to evaporation from such a small pond!

You learn something new every day

 

[Big Lou]

Wow! Very glad your made the discovery.

 

[Nepen]

I'm glad you figured it out.
I had a lot water evaporated from my pond before and it was very interesting because one day the water would be fine and the next a few inches drop (it was a big pond so it'd be 100 gallons gone woosh) and I couldnt figure it out. I havnt had any problem since last summer so I know mine is simple evaporation too.

 

[AJ1500]

good thing you figured it out, I would think that if the netting is porous material that it acts like a sponge and absorbs the water
expanding outward until the entire net is saturated, at this point you have a large area able to evaporate. if you wanted to leave the net I would say let it lay level on top but in the water

 

[Tula]

Wow, pretty surprising to me too! I really like your net, so hope you can figure out a way to keep it and your water

 

[Lisak1]

Evaporation can be surprising, for sure. As can splashing, which also adds to evaporation rate. We haven't had measurable rainfall here in several weeks and are noticing the amount of evaporation as a result. Glad you figured it out!

 

[cas]

How interesting - thanks for sharing.

 

[addy1]

Unreal, I would never have thought that. Thanks for sharing.

 

[j.w]

Strange and who would have ever thought! Maybe you can raise the net up to where the fountain won't hit it. Course it means if you want the net covering the whole pond then you have to have little sides on it down to the pond. You needed something more to do to take up your time tho anyways right

 

[Becky]

I'm pleased to hear you were all as surprised as I was!

I would think that if the netting is porous material that it acts like a sponge and absorbs the water
expanding outward until the entire net is saturated, at this point you have a large area able to evaporate.

Yep, exactly that. I imagine the fact the net is black (and therefore absorbs more energy from the sun) was not helping matters either!

It would be quite tricky to either raise or lower the net, so we're going to see how it fares without it for a while. I do like being able to see the pond without the net though, so I hope it will be ok. The reason we got the net in the first place was following a heron attack when we lost 4 fish, so I'll start looking into some deterrents!

 

[mrsclem]

I put burlap fabric over the 3 55 gallon barrel filter I have on one pond. If it drops down into the water, it wicks it up and there is water running off the edges! Lost 8" of water overnight. I now have netting to keep the fabric out of the barrels.
Love your pond and net!