pond overflow pipe clogged

[Margonme]

Ebenezer:

I am sure you have seen some huge piles of debris around those trash guards on the top of the riser of the principle spillway.

The subject here is clearing out the inside of the pipe. However, keeping the trash rack clear is also a chore especially in the mountains of Appalachia.

I was performing a coal mine inspection in Martin County, KY. The reclamation supervisor said they had a problem they were fixing.

The problem was they had blown the top of the riser pipe to kingdom come. A huge pile of limbs, logs, leaves, twigs, etc. had accumulated around the top of the riser. The impoundment was discharging through the emergency spillway. They took a boat out and laid explosives in the debris. The blasting crew must have got too aggressive. They took the debris away but with it they destroyed the riser pipe.

 

[BobbyLummus1]

I had a walk and talk with property owner before buying the property . Hard for me to remember, I do know the army corp has to approve pond site here . He stated he remembered a hold up building the pond dam due to getting this right . What I don't understand is it's a 6 " pvc pipe that tees on the pond side and goes down towards the bottom . Will take pic tomorrow. Oh and it's s small 2.5 acre pond in middle of cow pasture with nothing in site

 

[Margonme]

I had a walk and talk with property owner before buying the property . Hard for me to remember, I do know the army corp has to approve pond site here . He stated he remembered a hold up building the pond dam due to getting this right . What I don't understand is it's a 6 " pvc pipe that tees on the pond side and goes down towards the bottom . Will take pic tomorrow. Oh and it's s small 2.5 acre pond in middle of cow pasture with nothing in site

Bobby, if it tees toward the bottom that is sometimes done to avoid floating debris when a trash rack is not used or does not fit the design.

 

[BobbyLummus1]

I studied the tee toward the bottom today and thought probably easiest to cut that off and add new? doubt the trash pump hose will curve with the debri guard on the end . JMJ I rented a trash pump 2" this evening . Biggest they had at home depot . Also got 60 ft of pvc to attch to the 20ft hose it comes with . Gonna try this first thing in the morning . Question , the hose it comes with has metal debri guard on the end I assume I need to leave that on there ? Looks like it screens the big stuff . several have mentioned the danger on the pond side ( is that for the just big pipes or is it dangerous to be in the water close with my small 6" pipe while working ?

 

[Ebenezer]

I am a PE and retired from NRCS. 6" is fine if it is set up to store/pass the 1YR-24HR storm. Not at all an unusual size on a small dam with a well matched watershed. The easiest and safest thing is get a contractor to help you who has or will rent a decent air compressor or use a water pump with adequate pressure and gpm. Let him create a packer on the backside with a thru pipe to send the air. Then pump the air and blow the trash back out of the riser or intake end of the siphon. If it is a riser, be sure to have a decent trash guard to drop on it once you get it cleared.

Ebenezer, under federal surface mining regulations, the primary discharge pipe had to pass a 25 year 24-hour storm event. As a Professional Engineer, you understand those numbers are based on the acre feet of water calculated for the watershed above the structure. I have inspected hundreds of sedimentation basins in 10 different states and have never seen a 6 inch primary discharge pipe. Of course, the difference in the design between a one year event and a 25 year event may account for that.

On basic farm ponds the ESW is designed to carry the 10, 25 or 50 YR-24HR storms depending on criteria or the size of the watershed either set by the national NRCS standard or state variation. Get over into the watershed and high hazard dams (NRCS called them TR-60) and you begin to bump up PSW capacity and get into the PMP/PMF or fractions of it for the ESW based on state or federal regulations. Seismic zones also play into criteria. Storm water runoff ponds for development are different still. Nothing simple.

Don't try pressure removal of debris on CMP when you do not know if joints are banded or flanged. Flanged = OK. Banded is not for internal pressure and you will mess up.

The local NRCS office might still have a design for the dam that started this discussion.

 

[JMJ Farms]

I studied the tee toward the bottom today and thought probably easiest to cut that off and add new? doubt the trash pump hose will curve with the debri guard on the end . JMJ I rented a trash pump 2" this evening . Biggest they had at home depot . Also got 60 ft of pvc to attch to the 20ft hose it comes with . Gonna try this first thing in the morning . Question , the hose it comes with has metal debri guard on the end I assume I need to leave that on there ? Looks like it screens the big stuff . several have mentioned the danger on the pond side ( is that for the just big pipes or is it dangerous to be in the water close with my small 6" pipe while working ?

Yes leave the screen on there. It will filter anything that's not capable of passing through the pump. And also be extremely careful even with a 6" pipe IF THE TOP OF THE PIPE IS UNDER THE WATER LEVEL. When the pipe fills up with water it will create a very powerful suction. This will take a few seconds or possibly a minute or two. But it will create a vacuum that is potentially dangerous. Just be careful and use common sense. You will be safe in a boat but if you were to get your arm or leg or whatever caught in that suction you would probably not be able to pull it lose.

 

[Margonme]

I am a PE and retired from NRCS. 6" is fine if it is set up to store/pass the 1YR-24HR storm. Not at all an unusual size on a small dam with a well matched watershed. The easiest and safest thing is get a contractor to help you who has or will rent a decent air compressor or use a water pump with adequate pressure and gpm. Let him create a packer on the backside with a thru pipe to send the air. Then pump the air and blow the trash back out of the riser or intake end of the siphon. If it is a riser, be sure to have a decent trash guard to drop on it once you get it cleared.

Ebenezer, under federal surface mining regulations, the primary discharge pipe had to pass a 25 year 24-hour storm event. As a Professional Engineer, you understand those numbers are based on the acre feet of water calculated for the watershed above the structure. I have inspected hundreds of sedimentation basins in 10 different states and have never seen a 6 inch primary discharge pipe. Of course, the difference in the design between a one year event and a 25 year event may account for that.

On basic farm ponds the ESW is designed to carry the 10, 25 or 50 YR-24HR storms depending on criteria or the size of the watershed either set by the national NRCS standard or state variation. Get over into the watershed and high hazard dams (NRCS called them TR-60) and you begin to bump up PSW capacity and get into the PMP/PMF or fractions of it for the ESW based on state or federal regulations. Seismic zones also play into criteria. Storm water runoff ponds for development are different still. Nothing simple.

Don't try pressure removal of debris on CMP when you do not know if joints are banded or flanged. Flanged = OK. Banded is not for internal pressure and you will mess up.

The local NRCS office might still have a design for the dam that started this discussion.

The ESW on a surface mining impoundment has to pass a 100 YR event. I inspected them but I didn't design them but I have worked through some of the issues when we had to sit down with the engineers and look at the watershed. It was interesting that in some watersheds the 100 YR events was not a great difference from the 25 YR events.

I can see farm ponds are an entirely different kettle of fish.

 

[TexasBred]

I worked for the Soil Conservation Service a couple of summers while I was in college (I think it's called NRCS today). Margonme described exactly how we designed and built ponds in the '60's. Six inch diameter pipe sounds very small to me. Sure to clog easier and faster. Best bet might be to install a new one.

And put a 90 on the end of it pointed down into the water. Will keep trash out better than one turned up so trash falls in.

 

[Margonme]

I worked for the Soil Conservation Service a couple of summers while I was in college (I think it's called NRCS today). Margonme described exactly how we designed and built ponds in the '60's. Six inch diameter pipe sounds very small to me. Sure to clog easier and faster. Best bet might be to install a new one.

And put a 45 on the end of it pointed down into the water. Will keep trash out better than one turned up so trash falls in.

Yes. Same concept that is used on septic tank outlet to prevent floating solids from discharging into leach line.

 

[True Grit Farms]

http://www.meatprocessingproducts.com/b ... gQodjWwJiQ

This basket with a piece of all - thread makes a great pond screen. Put the basket 6" above the PVC and the pipe will never clog up.

 

[wlamarparmer]

My Area all ponds/lakes appear governed by USCG. this falls into the Chattahoochee River watershed.
Though not used today, is a navigable watery, plus multiple issues Ala/Ga on water use. Know several
farm pond construction issues shut down, and multiple trip to Coast Guard Office, Savannah, Ga to resolve.
From what I gather, if navigable waterway, USCG pretty much has Carte Blanc on any watershed into said
waterway. that how appears to work here. West Central Georgia.

 

[wlamarparmer]

My Area all ponds/lakes appear governed by USCG. this falls into the Chattahoochee River watershed.
Though not used today, is a navigable watery, plus multiple issues Ala/Ga on water use. Know several
farm pond construction issues shut down, and multiple trip to Coast Guard Office, Savannah, Ga to resolve.
From what I gather, if navigable waterway, USCG pretty much has Carte Blanc on any watershed into said
waterway. that how appears to work here. West Central Georgia.