WATER LEVEL

[Neil Cheney]

I have two ponds with a blade connecting the two. The smaller pond pumps water into the larger pond and then overflows via the blade back into the smaller pond. I have noticed that the water level in the smaller pond decreases over time probably from evaporation and aquatic plants and the odd passing cat. The larger pond level remains constant although it does rise a little when the pump is operated otherwise it stays at the level of the liner. The smaller pond level drops and the liner becomes visible fairly soon even when the pump is not being operated. Is this normal?

 

[Lisak1]

Welcome!

It sounds like it's normal for THIS pond. Is this when everything is running? I'm taking a wild guess that the big pond overflow is set to a level that it will stop flowing before the level drops below the liner. And I'm thinking it's better this way, as you wouldn't want the reverse - the big pond to keep sending water into the little pond and overflow it when the pump is off.

Am I understanding the question?

 

[Neil Cheney]

When the pump is running the water level in the smaller pond drops below the top of the liner as water is being pumped into the larger pond which is twice as big and the level of course rises and then returns via the blade to the smaller pond. What I’ve noticed is that when the pump is not running the water level in the larger pond remains constant even though the level in the smaller pond has dropped. What happens is that over time the level in the smaller pond drops by a few inches possible from evaporation but the water level in the larger pond always is constant when the pump is not running. It seems evaporation from both pond is only seen in the water level of the smaller pond.

 

[Lisak1]

And the small pond is the lower pond, correct? Maybe just because the water volume is smaller, you see the loss faster? If you fill it up, does it hold the level?

 

[Neil Cheney]

Yes, the smaller pond is the lower one. When I fill up the small pond the water level holds when the pump is not on but over time the level gradually drops. I suppose the total area of the two ponds would lead to a fair amount of evaporation particularly in this heatwave but is does seem strange that the much larger pond maintains its level presumably at the expense of the smaller pond.

 

[Lisak1]

Yeah, I don't know how that would be if there's no water exchange happening though. The evaporation rate should be the same.

Post some pictures of your pond - maybe there's a mystery we can solve!

 

[Neil Cheney]

Thanks and please see attached

 

[Lisak1]

Oh my gosh! It's beautiful!

Well the only difference I can see right off the bat is plants in the lower pond vs none in the upper, but nothing extreme there, so I doubt that makes a difference. Logic would tell you the upper pond dumps into the lower until the water level is below the outlet, so it just must be set at a level that keeps that pond nearly full at all times. Why the bottom loses water faster - no clue. Greater surface area? More sun exposure? If it holds the water level when you fill it with the pump off, then it's not leaking. The mystery continues!

@MitchM - any thoughts?

 

[Neil Cheney]

Oh my gosh! It's beautiful!

Well the only difference I can see right off the bat is plants in the lower pond vs none in the upper, but nothing extreme there, so I doubt that makes a difference. Logic would tell you the upper pond dumps into the lower until the water level is below the outlet, so it just must be set at a level that keeps that pond nearly full at all times. Why the bottom loses water faster - no clue. Greater surface area? More sun exposure? If it holds the water level when you fill it with the pump off, then it's not leaking. The mystery continues!

@MitchM - any thoughts?

Thanks and it is a great feature expedite at this time of year. The photo was taken som4 time ago and roughly one third of the large pond is covered with water Lily’s and two plants and the small pond has just one plant. I saw two cats drinking from the large pond the other day as well as some birds so it probably not surprising to see the water level drop. The fish also presumably drink too. I suppose that the two ponds combined have a large surface area so evaporation is also reducing the level which is only seen of course in the small pond. I used to suspect that there was a leak but I’m feeling it’s just the environment and aquatic life that’s causing the water loss. I shall keep an eye on it over the winter as I’ve only had to look after it from March this year.

 

[Stephen Noble]

'Bing,' in Star Trek lingo, I just transported your magnificent setting to my backyard! Simply beautiful.
Stephen

 

[Lisak1]

@Neil Cheney - fish don't drink. But knowing that you have lots of plants does explain some of the evaporation. Plants take up LOTS of water and "breathe" it out into the atmosphere. That's why they are so useful to the planet - they help clean the air and add good things back in!

 

[Neil Cheney]

Lets hope it starts raining soon.

 

[Lisak1]

Lets hope it starts raining soon.

I'll second that one! We call that "free pond fill up!" We're supposed to get some rain later this week - fingers crossed!

 

[MitchM]

..

@MitchM - any thoughts?

It sounds about right, especially if 1/3 of the upper pond surface area is covered by lily pads.

...The fish also presumably drink too. ...

Fish don't consume water. They maintain an ionic balance with the minerals in the water via osmoregulation.

.

 

[Neil Cheney]

It sounds about right, especially if 1/3 of the upper pond surface area is covered by lily pads.



Fish don't consume water. They maintain an ionic balance with the minerals in the water via osmoregulation.

.

So to “drink like a fish” is actually the opposite of what most are suggesting.