I need pond dredging and excavating ... and advice

[DaRube]

I have a quarter acre pond that is 30 years old. The inlet end of the pond has silted in, and the drainpipe that goes down through the earthen dam .... the metal of the top foot or two has eroded away and there may be blockages as well. Because of the damage to the drainpipe, the water level is that much lower than it should be.

Therefore, I am considering having the dam burst, replacing the pipe, having the pond dredged, possible deepened and enlarged, and having the dam rebuilt with a new drainpipe.

I have also had problems with the pond overflowing down an inadequate spillway. Last year, a very wet year, the pond overfloyed nearly 2 dozen times. This year, maybe a half dozen. When it overflows, the water goes out through a partially wooded area, covering perhaps another quarter acre or more. I am starting to see erosion damage in the wooded areas, and there are also spots that stay wet and un-tractorable. I don't want these spots to become permanent wetlands. So I am thinking of having a burm built to direct the spillage in more manageable ways.

There are several other excavating projects that I need done as well (I have 10 acres).

I am thinking that it makes sense to contract a single excavator to deal with all of these tasks at once. I also view the pond and water management problems as "systemic", and would like to implement a solution that improves the entire system.

Some of my questions are:

1) Since the dredging will produce lots of silt, mud, etc., can this stuff be used to build the burm, to fill in holes and other low spots on the property, etc. Or does silt prove inhospitable to the growth of grass, or non-porous, leading to other standing-water problems? Could there be toxins in the mud? (My pond is fed by runoff mostly from neighboring crop and cattle farms.)

2) Are there considerations for how the banks of a pond should be shaped? Are there treatments that should be applied to the banks to keep the pond healthy longer?

3) Are there specialists who I should hire to help me design and strategize this work? Or is nature pretty forgiving, so that I stand a good change of getting it right on my own?

I live in Northern Virginia, not far from the Maryland and West Virginia borders. So I am open to referrals.

Thanks in advance!! [img]/forums/images/icons/wink.gif[/img]

[Fishman]

I think you should hire someone that specializes in pond repair. If they are capable of doing the other work, then fine, but don't hire a "dirt mover" to work on your pond or you might regret it. Get references.

You might consider getting an "outdoorsy" professional involved, such as a lake or ranch manager to help you with the details. You might be able to do some really neat things that just wouldn't occur to you otherwise. For example, excess water over dam + marshy areas below = potential duck hunting spot if properly managed (at least in my mind).

Check on permit requirements for your area. Some states are funny about that.

I doubt that there would be any problem with the sediment in the bottom of your pond. However, even after cutting the dam, it will take quite a while for the bottom to dry out enough for heavy equipment. Perhaps a large excavator might be in order?

Make sure you don't compromise the clay layer in the bottom of the pond or it will leak.

As far as slope, make sure your dam is 3 to 1 or less. The sides of the pond should be sloped so that the water depth exceeds 3' as close to the bank as possible. Lots of shallow water = lots of aquatic vegetation, which is usually a nuisance in such a small pond.

Lastly, you might consider eliminated the overflow pipe alltogether and just rip-rapping your spillway. This would prevent someone from having to do this again in 30 years.

You need to get an expert. Nature is not forgiving at all. Your prevailing wind slope on the pond needs to be right or you will get erosion. You need an adequate core trench. You need adequate pond slope, size, inlet, outlet, etc. to get a good fill and prevent erosion. There are alot of variables that go into it.

To get started I would go to your NRCS. National Resources Conservation Service. They have alot of free information and will usually design your pond for free.

[Pat]

I second the NRCS suggeston. Do not worry if any locals tell you stories of excess regarding the NRCS designs. NRCS has well engineered designs that typically exceed the seat of the pants good ole boy approaches that sometimes work/last. (not just ponds but fences, gates, cattle guards, etc.)

Be careful about excavating the pond deeper than it was originally done as you may do the equivalent of pulling the plug from the drain in a bath tub. If it is fairly old it may be significantly silted and you could get a lot more pond after it is cleaned out without going beyond original depth. If you want more, consider larger area not greater than original depth.

I found I could get a LARGE track hoe (4 ft bucket) with very experienced operator for the same price as a decent dozer with operator. The large bucket and good reach will let the track hoe clean a lot of the pond without having to break the dam and wait for the bottom to dry. If you have any spring fed action to the pond, it might not dry. Even when pond bottoms look dry and you can drive across in a pickup, you may break through the crust with heavy equipment.

I added a drain to a pond dam that didn't have one and had been washed out at one end. Job was done with the track hoe excavator. We welded a large anti-erosion collar to the 12 inch drain pipe and packed clay to fill the trench we cut through the dam. It has held perfectly with no seep when the pond has been full and overflowing.

With a small pond like yours, a track hoe can reach a significant amount of the silt from the edges. Someday you might want to set up a drag bucket on a cable and use your tractor to pull out silt from where the track hoe can't reach.

Best of luck to you. Let us know how it turns out.

[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]

[egon]

That silt on the bottom is good for growing things but shouldn't be used for structural purposes.

Egon

[donh]

<font color="blue"> Someday you might want to set up a drag bucket on a cable and use your tractor to pull out silt from where the track hoe can't reach. </font color>

Recently, when I had my pond dug by a large excavator, we sent the excavator next door to my daughter's house to clean out their pond. They did a nice job, getting rid of all the silt, debris and hydrilla, and resloping the banks.

But, now the hydrilla is starting to come back. This has been an ongoing problem for them. They've tried draging things like old bedsprings through the pond, which works for a very short while. It may also become a problem for my pond, sometime down the road.

So, I'd love to rig some sort of a drag bucket to be pulled by my tractor on a cable, but I don't have a clue what it would look like. I think I can envision how it might work -- drop the bucket on one side of the pond, drive around the pond dragging the slack cable behind, and then drive away from the pond once the tractor is directly across from the bucket. When the bucket gets to the near side, lift it, empty it, and position for a pass back across in the other direction. Do I have the gist of it?

If so, what I need is some idea of the shape of the bucket and the way in which it would be rigged to pull with the right angles. I tried a Google search and came up with some references for a tractor-pulled drag bucket, but no detailed photos or drawings.

[Fishman]

Don,

Don't know if herbicides are an option for you personally or not, but there are some good ones that will take care of hydrilla. Some don't even require specialized application equipment. Another option is triploid grass carp that just love hydrilla. I think Florida allows those but they may have a permitting system like TX. Just need to contact your local biologist. You'd need to make sure that the plant was indeed, Hydrilla, because it is often misidentified. See this site for some good pictures.

Dragging out weeds with a tractor can be fun . . . I guess, but it's a never ending process. Most times the results are less than stellar as well.

[DaRube]

You guys are great .... as usual!!! [img]/forums/images/icons/smile.gif[/img]

Calling the NRCS sounds very wise. Pulling this design together will be one of my winter projects, in preparation for making it happen next spring. And believe me ... I will share pictures with you guys when the work is done. [img]/forums/images/icons/wink.gif[/img]

[Pat]

Don, An effective way to use a drag bucket to scrape silt from a pond is to have the "POWERFUL" vehicle (tractor, dozer, wife driving a team of mules, or whatever) pull the bucket in the scraping direction and another vehicle pull it on the back stroke. The power requirement for puling the bucket on the "backstroke" is way less than in the "productive" direction.

It requires only a little bit of coordination between the drivers so the "pull back" line is slack when the "main line" is in tension and vice versa. Hand held radios (FRS or GMRS radios, CB or whatever are way better than hand signals and horn blowing.)

There are various configurations for rigging a drag bucket and I am no expert. Some use a bridle that allows setting the "angle of attack" so the bucket doesn't "dive" and require too much force nor just skip across the surface. You can rig two cables so that blade angle can be adjusted while making a cut till you have it right. The retrieving cable is connected (with or without a bridle) so that it doesn't dig in or flop into some high drag position and make it hard for the retrieving vehicle.

It is possible to use a double bucket (or two buckets back to back) and use two powerful vehicles so you remove material "coming and going" on both strokes.

The operator on the production side can slightly change his line of pull. The retrieve driver just follows that lead and stays in line wilth the lead driver. This way you can move around and access different parts of the pond.

I'm sure you can find pix or dimensions for buckets. Think of a drag bucket as a FEL bucket being towed. As you have less finess of control, you want a bucket considerably smaller than what the tractor would come equipped with so you don't "stick" it. If you are just going after silt you shouldn't have to downsize the bucket too awfull much. I'd recommend something like about 1/2 size of FEL for that machine or a tad less since you have much less precise control.

[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]

[egon]

Mayhaps check into some of the old English steam plough cable systems.

Egon