Hi all,

I have owned this property for almost a year now. There is a damed pond, almost 2 acres in size. It was built in 1966. Here is an aerial that I had taken this past fall


There is an iron overflow pipe built into the dam which spills into a small crick. The as-built drawings from 1966 (very faded)show a vertical section of ~15 feet with a horizontal section angled at ~27* and 110 feet long. I believe the pipe is old gas line pipe, as at the outlet, it appears to have a wrapping on it. This is/was very thick pipe. It is hard to imagine that it is leaking but the previous owners had a sink hole filled a few years back. Now in the same location, I noticed a small sink hole forming last fall. Pretty small, could maybe fit a basketball into the size of it. Now that the snow is melting, I've noticed that it has gotten bigger.

Maybe it's just the dirt settling after a few years, but I'm worried that the pipe is leaking and washing out below. Unfortunately the previous owners are no longer alive and I can't get much history.

I'd like to address the problem with a solution that will work. But as you all know, as a new home owner, funds are a major issue. I'm an engineer, I'm handy and I know a lot of people with a lot of skills. I really feel this is something that I can fix, I am just not sure what the best route is.

The previous owners did get a quote to have the existing pipe replaced, like for like, at over $20,000!! No thanks, I'll drain the pond for that money.

Here are some pictures
A view at the typical fishing location. This is also where the emergency spillway starts


This shows how steep the banks are, all around the pond.

A view of the dam. It's very big and VERY steep. I need to find a way to safely mow this...


A view from the outlet, looking up


Inlet and trash rack


Outlet


You can see the outlet has some sort of wrap on it. You can see the corrosion on the outlet, but this is exposed to air and water, so I'm not overly concerned about this part


Another view of the dam


So how can I fix or replace the spillway? Replacing it with another deeply buried pipe seems pointless to me. At some point, steel will rust or the plastic will crack or a weld/joint will crack and I'll have the same issue again...many years down the road.

My thought is, why not put a vertical outlet near the top of the dam, and run it angled down, laying on the dam hillside. NOT buried, and exit at the existing spillway/outlet? This would require minimal excavator work and would allow the pipe to be above ground, for easy inspection and cheaper installation. Will the pipe look ugly sitting in the open? Sure, but will it be 10x cheaper to install and should be just as effective, I think so...but that's why I am here, and that's why I'm asking.

Here is a terrible sketch, but hopefully it gets the idea across....

So, what about my idea? What about my other options that I might not be aware of? I did get a quote to have the existing pipe relined and it was close to $20,000 as well. This has to be a low budget build for me. I'd like to do it myself.

Oh, I believe the outlet is ~12" and the inlet is a little larger, I can't remember off the top of my head.

The previous owner had a company run a camera a few years back, they said it looked fine. He said it was low quality and they probably missed whatever the issue is. But, he has since passed away so I'm out of history.

What are my options and THANK YOU for the help!!

That looks like asphalt/tar coated pipe.

The sinkhole could be a tree stump that is decomposing.

First thing I'd do is call around to different plumbers or sewer guys and see about running a camera thru the pipe again, this time better resolution. No need to do anything until you know it's bad. Why spend the money to fix something if it ain't broke?

If it is bad, look at getting the pipe filled on the pond side with hydraulic grout and installing a siphon system.

Next get to work on the cattails and lilies.

Without cathodic protection that pipe should be expected to be at the end of its expected life. I would guess that pipe has leaded joints which have very little resistance to settling and all earth dams settle to some extent. However, I agree that confirming you have a problem may be in order before spending money on repair.
If you want to do it yourself, as you stated, you can buy an underwater camera with LED lights and 100' cord for less than a plumber will charge to come out and do it. Flush the pipe as best you can then temporarily block inlet. Attach camera to long pipe and go exploring. Best of all, when you are done you can spy on your fish.

Thank you all for the reply.

Esshup - I agree that it could be a stump, however I have a State of Ohio inspection report from ~1999 which makes no mention of a tree on the dam or any pictures of one. Unfortunately, I did do some calling around in the fall to see who could run a camera (a good camera) and I was stuck with the same company that did it a few years back. Not a lot of need for it around here I guess?

I agree, don't fix it if it aint broke. Can you provide more information on a siphon system? I keep seeing them mentioned but my thought was that those are only used to lower pond levels when needed? Would they be easier to install? Or a DIY project?

Any advice on the cattails? Stupid things are bothering me too!

Bearbait1 - I believe the pipe has welded joints. At least that's what the original drawing called out for. Can you suggest a camera? I wouldn't know where to start? I think the plumber with the low quality camera wanted to charge $250 for the visit and $100/hr afterwards.

Well, if you are worried about holes in your dam then maybe ground penetrating radar could be the solution. It could show where the hole is and then you would be sure which way you should go.
Probably it can be used only if a friend owns one otherwise it might cost much more than a plumbers visit. Yeah, an experienced operator is needed as well.

I have a 15 year old aquaview and it works great. I've watched professional snake cameras at work and my aquaview is almost as good you just have to jury rig a way to attach it to a pipe. You want to attach it so it is a few inches above the bottom as you slide it along. I think you can buy an attachment accessory for some of the cameras. I know there are a couple of underwater camera makers, Cabelas carries some.

That's one toy I wont have access to (Ground Penetrating Radar)

I'll do some looking tonight and look at an Aquaview and whatever Cabelas offers.

Might be a good excuse for another toy!


Lets assume that my pipe has a leak, is a siphon style the way to go? Is there a sticky for FAQ that would explain this system? I always thought a siphon style was to drain a pond only, not to maintain a level

A siphon will maintain water level, but have no personal experience with them, only what I have read. Google "pond dam siphon" and you will find some simple drawings. The search feature on this site sucks so to search this site for info use google and search "pond boss siphon" or something similar.

http://www.ponddampiping.com/syphon1.html

Well I emailed the State of Ohio Department of Natural Resources, who has to approve all modifications to my dam, and they said a siphon system is not appropriate. I asked for a reason why.

They wont let me perform any modifications without their approval and the sign off from a Professional Engineer.

I'm about ready to just drain the pond and say the hell with them.

They told me to slip line or replace the pipe with the same style (which I had quoted at $20-30,000)

I'd be a shame to have to drain a pond that is almost 50 years old because of something like this.

Wow, I thought most states were just worried about ponds over 50 acre ft. Are all ponds in Ohio regulated like this?

Apparently? I'm not sure. I have a yearly fee to pay, which is based on the class of pond (I-IV) and the size of the dam.

This is ridiculous. Quite agitated...

Mine is listed as 27.8 acre ft by the way...

Well, since they have their finger in the pie so to speak, ask them what programs are available to help fund the replacement.

I'm really interested to hear what they have to say about the siphon system - why it's not allowed. If they don't reply, keep pressing. It might be that they just don't know how they work, and once they find out they'll say yes.

If there isn't a lot of water in the pipe, I wonder if a mini GoPro camera on a small RC car would work?

I am curious as to how you found out that the ODNR has to approve all modifications to the pond? What makes this pond different, etc? I would contact Bill Cody and see if he knows anyone out your way that deals with pond repairs. If there is, they may know how to work with these entities to get your work done. Bill's in Ohio, west of you.

Hard to believe that a siphon system wouldn't be allowed, if installed properly. I would think that it could handle more water than a same size regular pipe.

It can!

Esshup - I agree. ODNR's website states funding (loans) are available, on a first come, first serve basis. Still, I can't float a $30k repair bill. I fished for a whole 60 minutes last year.

I'm curious about their view on the siphon system as well, which is why I asked "why is it not appropriate?". Waiting on a response. I sent them the link above, that shows a system. Hopefully that will clear the air. I have a "backup" siphon system to lower the pond if needed. I'm hoping that is what they are picturing. But the system shown in the link, is automatic for level control.

The pipe in question is 12" ID, so a GoPro and an RC car would work. I just need to get enough light in there.

fish n chips -
I found out from the previous owners that ODNR has to approve everything. The ODNR website also states that they must approval all changes first, and you must have a Professional Engineer (of your own) sign and approve everything before submitting. They also remind you with just about every correspondence as well.

Could you message me the contact information for Mr Cody? Or is that his name on this board? I haven't had any luck finding people in this area who can work with this size of pond. It's either small Koi ponds, or huge state funded projects.

I think we all agree a siphon is just fine. I'll even put a larger pipe in, if it'll make them happy.

Info on Bill:

http://forums.pondboss.com/ubbthreads.php?ubb=showprofile&User=24

He's one of the moderators here too.

Thank you!

I received a response from the ODNR:
"That type of siphon system is known as a bottom withdrawal siphon system, It could be used in this case but needs to be properly designed by an engineer in regards to hydraulics and pipe forces. Also if you choose to go with abandoning the current spillway pipe system it will need to be completely filled with concrete grout to be considered safe and abandoned.

In regards to the open channel system I have attached 2 fact sheets about open channels. Your dam currently has a small open channel emergency spillway which could possibly be modified to act as the only spillway. The most important issue with open channels is erosion control, especially when they would have constant flow.

Again, any modifications of this nature would need to have plans submitted to us by a professional engineer."


I know a PE or two...however I don't know anyone who designs these types of systems. Seems like another major expense?

Such things happen. Maybe you'll get a project with simple ideas that every student can tell but anyway it will be additional expense.

I'd think that the company that I linked to might have an engineer on staff. If not, I'm sure they'd know of one. It'd be worth a call.

I'd be leery of using an open channel for a primiary spillway. Like they said, too great of a chance for a dam blow out without extensive erosion control methods. I think siphon system would be less expensive.

12" dia pipe, 100' long needs aroughly 3 cubic yards of grout to fill.

I just gave them a quick call. Unfortunately, no engineers on site. He recommended calling the NRCS for recommendations. I'll see if Bill Cody has any recommendations for me.

They were more than willing to talk and work with whoever I have look at the project.

I'm leery of open channel as well....that's sort of off the table in my mind

Good thinking! I agree.

How deep is the pond? My neighbor has a pond, and he said that if it gets "x" number of feet deep, then the pond goes under certain regulations. He took two feet off the top of his dam and readjusted his outflow level, just so he wouldn't be hassled. I just am at a loss of why the ODNR is involved in your pond.

Not exactly sure on the depth. As built drawings suggest only 15 feet or so.

Is your neighbor's pond dam'ed? That's why the state is involved with mine.
http://ohiodnr.com/water/dsafety/whatdam/tabid/3342/Default.aspx

Mine is a Class III, according to ODNR:
Class III:

Dams having a total storage volume greater than fifty acre-feet or a height of greater than twenty-five feet shall be placed in class III. A dam shall be placed in class III when sudden failure of the dam would result in at least one of the following conditions, but loss of human life is not probable.

(a) Property losses including but not limited to rural buildings not otherwise described in paragraph (A) of this rule, and class IV dams and levees not otherwise listed as high-value property in paragraph (A) of this rule. At the request of the dam owner, the chief may exempt dams from the criterion of this paragraph if the dam owner owns the potentially affected property.

(b) Damage or disruption to local roads including but not limited to roads not otherwise listed as major roads in paragraph (A) of this rule.


The ONLY item I can see that I meet, is that they classify the height at 26.7 feet or something around there. I believe that is the height of the dam, not the depth of the pond.

I don't have much to add for this thread. Working with anyone governmental is frustrating. Your pond probably was designed by Soil & Water and approved by the state which is why they are involved. Once they have you on record they are always in the "loop". I'll be back later after I look something up.

Thank you for the reply Bill. You're probably right...I was just hoping since it took place in 1966...they would have lost the paperwork!

If you know of any PE's in the area, let me know.

There is a home owner association near me that have two ponds one 7.5 ac and another 16 ac. Both use cement spillways for water release into Maumee River. No overflow piping.
http://www.zillow.com/homes/for_sale/Bowling-Green-OH/pmf,pf_pt/house_type/23789_rid/days_sort/41.443768,-83.777774,41.439385,-83.784458_rect/16_zm/

I think a well designed spillway with large riprap basin that released excess water down your hill would work for a 2 acre pond. Wouldn't a bouder lined spillway be acceptable instead of a cement lined one work? The pond is only 2 acres for God's sake. We are not talking about a high water volume lake situation with a huge 1000acre watershed here.

Since you are an engineer and for this simple project you should be able to design something yourself and get it approved - stamped by the required engineer (PE) whoever that may be in your region. You should be able to do most all the required calculations and design. This is not rocket science. Do some research on spillways and spillway design and see if it won't work for your situation. Often in larger water bodies there are two spillways one major to handle 98% of the water flows and one emergency for the 100yr flood event.

I do have a contact for a soil scientist that used to 'service' NW Ohio. Now retired and consulting. I can get you his contact info if you want it. He may know of professionals to provide assistance.

It's the 26.7' dam height that is the root of your troubles, I wouldn't have imagined it was so tall.

Bill -

I'm a bit nervous about a spillway. Mainly with erosion occurring underneath the concrete or the boulder lined one. It'd be nice to have a waterfall type spillway, but I think it might cause more issues in the long run. I even thought about taking a large diameter pipe, cutting it in half and making a U-shaped trough down the hillside. Like a spillway....sound crazy? It'd be easy to look for leakage and monitor the flow.

I was thinking the siphon design would be easiest and cheapest to install? The link above, pretty much sells the siphon system as a kit, in my view. I can do a quick CAD drawing and hopefully get a PE to sign it and be on my way. I don't know if I will have to do any calculations. Not sure how to address that. ODNR hasn't asked for anything calcs (yet). That might be as simple as referencing flow charts for various pipe diameters and just going one size up to show that there is no issues.

I expect and hope the DNR desires calculations of watershed runoff flow amounts into your pond for historical large or heavy documented rain events in your region. That is just implementing good pre-planning and design. Watershed should be fairly easy to calculate with the aid of a USGS topographic map. The DNR may have on file the original plans and documents relating to design of the original pond. The sunshine law should give you a rights to view or receive copies of those documents. The original documents could save you some time and effort.

Erosion where there will be anticipated water movement is often controlled with concrete riprap. Broken concrete is often available free from concrete contractor's construction projects. You may need to draw down the pond's water level 5 to 8ft to accomplish whatever method you decide to use.

By impounding water you do have a responsibility to protect the receiving stream's integrity by having a sound dam and adequate oversized overflow structure / spillway.

IMO you need to do quite a bit more homework before deciding which plan is the best for you to use.

I've been speaking on and off with the DNR about this for about a year, and there has never been a mention of any calculations required. I honestly don't think they want to know the watershed runoff flow amounts. (However, I agree with you that perhaps they should)

However, flow rates of the proposed system would likely be required.

I currently have a riprap where my current drain is. It would have to expand if I were to do a large spillway. However, there really is a very small volume of water that goes through that pipe.

I agree, more homework is needed, as I haven't decided on anything yet. I'm completely open to ideas. So far however, the siphon seems like the most reasonable, and cost effective method.

Otherwise, honestly, the pond does not add enough value to me, to make it worth $20k or another high expense repair.

See added notes in my previous post about original documents at the DNR.
IMO a well designed spillway will handle and discharge a lot more water volume compared to a overflow pipe. However the overflow pipe allows slow release vs rapid release of a spillway. One has to consider the volume capability of the receiving stream.

Mike Otto of Pond Boss magazine wrote an article in the magazine about spillways and their design. Let me see if I can find that article in a back issue.

Here are some of the information items that I greened about spillways.
The first section is lists of fairly recent general discussion in Pond Boss articles in back issues about spillways and outlet pipes by Mike Otto.
Nov-Dec 2007 SPILLWAYS . . AVOID THE FLOOD. Otto looks at various types of spillways, their purposes, and considerations for building them. Fences on spillways are also discussed

Jan-Feb 2008. PIPE, PIPE, AND MORE PIPE. Otto discusses the reasons for an overflow pipe compared to a dirt spillway. Included are types of pipe, inlets, compaction around pipes, risers, siphon pipes, anti-seep collars.

Nov-Dec 2008 OVERFLOWING WATER KNOWLEDGE…CHOOSING PIPE. Otto tells what to do when drain pipes fail. Includes types of pipe, pipe terms, and varieties.

Nov-Dec 2012. PIPE. Otto tells all about types, sizes, best types, and uses of pipe and necessary parts for spillways, overflows, and outlets for ponds – lakes. Covers emergency spillways, and installation advice.



A google search yields lots of information about spillway design and construction.
YouTube 49 minute video about spillway design
https://www.youtube.com/watch?v=p1wAljba6Fk

I had lots more links but lost them in the transfer.

Thanks Bill. I'll have to do some more reading.

An update from ODNR, on why my dam is a Class III
"
The height of the dam is measured from the streambed at the downstream toe of the dam to the top of the embankment which yours is greater than 25ft, the other main determining factor is the road that is directly downstream of the dam. It would more than likely be damaged if the dam were to fail which also puts it in class III. I have attached a classification fact sheet to help explain our regulations.
"

Side note...any advice for the cat tails along the dam? The muskrats really enjoy them...

Use a glyphosate based herbicide that is rated for pond use. Shore-Klear, Refuge. Add an ounce or two of non-ionic surfactant to every gallon of tank mix. follow mixing instructions on the label for the herbicide.

Hey everybody.

I've noticed that the sink hole on my dam is slowly getting deeper and larger. Enough to where I can notice it over the past month.

It doesn't give me the warm and fuzzy feelings. I don't know what to do.

The previous owner paid the neighbor down the street (excavator) to dig down and repack the dirt a few years back. I've learned that much. But it looks like the problem is back.

Obviously there must be a pipe leak since the sink hole is back.

The State doesn't seem to want to be of any help, other than telling me that I need a PE to sign and approve any design before they will even consider it, to let me change or fix anything.

The final option, is drain the pond and be done with the anxiety. I'm not a fan of this option, the pond is pretty, it's nice to watch the wild life, but it's not worth the anxiety either.

I really don't know what to do. I'll probably call the local county guy and tell him what I think is going on. I haven't spoke with him yet. He will either help me, or it will open a can of worms and the state will want everything fixed immediately.

Well, I'm not spending a ton of money on the pond, I just can't afford it.

I'm pretty stressed and pretty disappointed...

If anyone has any suggestions (especially if you are from Ohio) I would appreciate it.

I'd siphon the pond down below the inlet. After you do that there should be zero water flow. If there is any at all the pipe is leaking.

If you stop flow then you stop erosion. Since the water is not leaking out around the outside of the pipe that end is still sealed. I'd consider trimming off that bottom end and welding on a cap.

Then I might mix up loose concrete and fill that pipe.

Then run a pipe at water level through the dam, and run it down the face to the bottom. A 12 inch pipe will move one heck of a lot of water. On the pond end put on a tee followed by an elbow, both pointed up.

That's exactly what I want to do. I can do all of that myself.

Problem is, the state says that my pond is a class III and that I need to hire a Professional Engineer to design and stamp everything, then I have to pay the state to review and monitor the installation....it's way overkill for a pond this small.

The ONLY reason I am a Class III is because my dam height is "26.5 ft" so they say. Anything over 25 makes it a class III. The height is from the base of the outlet to the top of the dam.

So you could have a 10 ft deep pond and a 26.5ft tall dam, and still be a class III...that is essentially what I have...

Back-fill the area below the dam with several feet of material. Put up the classic sign "Clean Fill Wanted" and perhaps that will resolve the issue? Bring the base of the dam up quite a lot that way.

That's what I want to point out, is that I could do what you stated. Or point out that my pond could be 1 foot deep and still be a class III with their regulations.

If I can get them to de-regulate, I can add the overflow without any fuss.

Actually, if I could just find a PE to sign off on a simple drawing showing the proposed new drain pipe, I would probably be okay. However, I'm having trouble finding a P.E.

What about lowering the top of the dam by 2'? Would that drop you below the class 3? Push the top of the dam down to the bottom and raise that area by two more feet. Do you need a permit to do that? After that's all done, plug the old drain and install a drain that would not make the pond fall in their permit range.

I'm very sorry you are having an issue with your new pond. From the arial picture your place looks amazing. I too have a new pond and would be so bummed if I was faced with what you are. I wish you all the best on this endeavor.

Realizing I have no idea what I'm saying....

A year or so ago the city brought in a very large truck with a lot of hoses and stuff. They were redoing the sewage pipes from the inside. They never tore up a street. I have absolutely no idea how they did it. But my understanding is they fixed old drain pipes from the inside.

Best of luck

Cold, ODNR supposedly maintains a list of PE's they consider qualified...ask for, or search online for that information.