Hi guys... great forum! We purchased a property with a 2 acre pond. It appears to have been put together well in the early 80's and seems to be in good shape. It's has a steady amount of water coming in from neighboring farms and a nice steady outflow out of the 18" horizontal overflow outlet. I have no interest in screening the outlet with the disaster stories I've heard from plugged screens... but is there any reason why I can't simply put an elbow on it to raise the level a couple feet and also help prevent fish from going through the existing horizontal drain so easily??
So the next question is where I can find an 18" elbow or maybe even a T Connect to fit? It's simply a typical 18" culvert... or any other ideas to make this work as well?? thank you!!

Did it on a lot smaller scale to three of my ponds.

Raised overflow on main pond

Raised level of forage pond

Raised level of sediment pond

Doubt if that will help much, but as you can see I made the use of concrete to finish two of the three jobs.

Thanks Snrub!!

The overflow pipe is a typical black plastic 18" culvert with a smooth inside... does anyone know where I could find an elbow that would slide inside (of any type of material)? I don't plan to make it permanent at this point... this was I could control water level if I decide to at some point.

I think they make PVC elbows in that size.

Thanks Bill... looking but can't find anything... I thought so too!

Here's a site that might have what you want.

http://www.pvcfittingsonline.com/catalogsearch/result/?cat=0&q=18+inch+elbow

Thank you!! I was just looking at that site. Maybe I'll end up just building a box around the existing pipe that can be staked down and removed... it doesn't have to be water tight. I have a decent flow as mentioned above so the water will come up.

There are water control structures that attach to the overflow pipe and control water height by adding or removing boards. I don't have a link right off hand but google "water level control" or something similar.

If it is just very temporary, you could just put a peice of plywood and cover about half the opening. T posts or something in front to hold in place till water pressure got against it.

Be aware of any large rain events coming so you could remove it if needed.

They ain't cheap. We have 2 inline ones on wetlands, and 2 inlet ones on ponds.

https://www.agridrain.com/shop/c85/water...rol-structures/

I brought my ponds up 5-7" per year to allow plants to adapt.

Good stuff! Thank you!!
I don't want to close the outlet off or down in size at all in fear of the big rains. Instead I simply want to change to a vertical outlet in place of the current horizontal in hopes of keeping a few more fish from escaping... then to also bring that water level up another 1'-3' possibly. At least for now, I want it as temporary as possible in case I decide it's best to revert back to the existing.

Well... for what I'm seeing the cost of piping or making something myself... this might be as good as anything. https://www.agridrain.com/shop/c53/catch-basins/p211/26-catch-basin-18-stub/
but I do like Rah's link too...

I am not sure the planned modification will change the fish loss much. The trick there is a lot of surface area on the screen. I use hog panels with 1/2" mesh fastened to the outside using hog rings. My panels form a "U" around the drain with the side runs cut to taper up the banks on either side of the drain pipe such that the top of all the panels are level. The smaller mesh can be cut shorter that the height of the hog panels so high water will flow over it if a gully washer happens. Not sure if I described this well enough to understand.

Understood completely... thanks Rah. My main focus is to get the water level up more than the fish loss. Thanks again!

I got mine from a commercial plumbing supply company.

They talk about custom models on their web page. Maybe they could make you one like that with a removable end panel so when you wanted the water back down just slide the end out and leave it in place for the next time you want to raise the water level.

Thanks guys!!

Maybe install a T instead of an elbow so you can just cap it when you want the water level higher?

I was thinking that too Bill... part of the issue is finding this stuff... but it's out there.

Commercial Plumbing Suppliers

Menards has a 18" dual wall HPDE 90 degree elbows:


https://www.menards.com/main/plumbing/ro...44451522965.htm

and

https://www.menards.com/main/plumbing/ro...44451524844.htm

What!!! lol... I looked for one of those on their site. Perfecto. Thanks!

You're welcome. Bear in mind there will be a lot of upwards force on the joint due to it displacing a lot of water - ie acting like a boat. You may need to encase it in concrete.

The water control structures are often held down with spiral ground anchors and a strap over the top.

The good info just keeps coming in! Thanks all!!

Planning to do the t-pipe now and plug the horizontal end. This will allow us to have a choice of a couple levels. After a year or two of ownership I can decided on more of a permanent setup.

Side not... I have a fish list now... I decided to hit it hard up front which will hopefully pay off down the road. I plan to do a little more homework on the pond before we dump them in but the plan is to get some fish back in this pond in the next week or two!

Pond is right at 2 acres
200 LMB
1000 BG
1000 HBG
400 Shellcrackers
200 Catfish
20 Grass carp

You probably already thought of this but just in case...I would spend a little time thinking about how I want to plug the end of the horizontal part of the T. An 18 inch pipe has a cross section of around 250 sq in. If you decide to lower the pond level from the vertical of the T to the horizontal, I would remove the horizontal plug while the drain pipe is still full. If you let the pond drain to where the vertical is not overflowing, level is still above the horizontal and the drain pipe goes empty, there could be a few hundred pounds of water pressure trying to keep you from removing the plug from the horizontal....In other words, I would think of a way to plug the horizontal that can be removed even if there are a few hundred pounds against the plug.

Just my 1 cent...

Shawk,
I did this exact thing when my pond was expanded back in 2014, but I used a 90 degree elbow instead of a T. I cut it and installed it extra long, then slowly started cutting it back and monitored water level in the pond. I actually cut it shorter than I wanted to, but went to a supply store and picked up a rubber pipe clamp. After I calculated the desired height for the correct water level, I slipped the rubber clamp over both ends of the drain (siphon) pipe and tightened them up. The water level is spot on even to this day, except for after big rains when the siphon runs over until the water level drops. Good luck.

I'm all ears with this thing Bill... so I appreciate all info.

Thanks Stick... Good to know others have done this! I have not plans to add huge amounts of water, but with the layout around the pond I think an extra foot or two would put it right were it should be... we'll see.

I would leave out the grass carp unless you have a serious vegitation problem, or only start with 2 and increase very slowly (2per year). From what I have seen here they can strip a pond bare of natural cover, stir up sediment when they run low on food, and getting them out is near impossible.

I think we may need a few in the pond... but I may hang tight and see how bad the pond gets this year too. Thanks!