Pond Boss Forums POND CONSTRUCTION Building a dam Pay me now...or pay me later

Last summer '06 our pond construction project was completed. As most new pondmeisters are aware, there is a seemingly endless laundry list of things that gotta git done, and right now. It also seems that the larger the pond, the larger the volume of work based on square footage.
One very (VERY) fundamental hunney-do for a new pond is the establishment of vegetation on the dam. I can sit here and spell out a litany of excuses, but the bottom line will remain the same. In the end, a little more than a year later, I regret not spending a little more time and money on properly establishing vegetation on the pond side of the dam.
-
A few spec's...
The dam is a fairly massive chunk of about 20k yards of soil. The pond side face is 3:1. There is a 20'+ wide roadbed and the backside is approx 12:1 where we filled in the valley. The dam length is about 325 feet, but it continues to support the roadbed over a small draw as it wraps around at one end. The other end of the dam runs directly into the top of the hillside of the valley it fills. This excavation summary will better illustrate.
-
It was the end of summer, so I wanted to get something in that would grow all winter. We seeded heavily with annual winter rye over the entire dam (front and back). It came in well behind and on top of the dam, but the pond side was weak. I full expected to re-seed and mulch the following spring with perennial rye...but...it kept getting pushed back and I was reasonably assured by the strengthening growth of the winter rye. We used the W.H.I.P. program to seed the roadbed and mass behind the dam with native grasses and wildflowers. This part came in pretty good; I'm pleased with those results. The face of the dam, tho, moved in the wrong direction as the winter rye died mid summer. The weeds and wild grasses that popped up all around the rest of the pond were non-existant at the dam (curious occurrence...?).
-
Here is where we are, right now; focus on the face of the dam. The roadbed is wide and flat, but sheds toward the pond side. Any substantial rain is running to 4 or 5 areas of focused water accumulation at the top toe, then over and down into the pond. Yep, we have some small ravines in the making. Most are small at 8" deep, the worst one about 12" - 16" deep. Not horribly bad and certainly no immediate threat to the dam integrity, but must be dealt with and stopped.
-
It's too cold to establish any vegetation right now, but I can sure do some preparation for this spring. Here is my plan. I do not want to mess up the good stuff we have growing on the roadbed, so I am going to try to leave that alone as much as possible. In an effort to extract something good from this, I see this focused erosion as a good roadmap, showing me where to do my work. We will bring in a rubber tired excavator and light dump truck. We will cut in 4 or 5 shallow run-off channels, line them with geotextile fabric, and fill them with rocks (they call it oversize...this stuff)

-
Next, I need to make sure that all the water accumulation goes directly to each of these new little spillways, so we are going to add soil to create a short berm along the entire top toe of the dam. I'm not talking a substantial ridge; only enough to move the water in the right direction along the areas that need it. This will be it for right now and will hold me thru the winter. Then, this spring we come back and use the excavator to scratch up the remaining embankment, fertilize lightly and seed heavily with perennial rye, and roll out the straw blankets. The berm will also be lightly scratched for seeding with the same blend of native grasses and wildflowers. We will add some of this to the pernnial rye on the dam face, also.
-
OK, tell me what I'm forgettin' or the hidden issues that I'm not thinkin' of. Or...gimme a better plan, cuz the excavator is comin' in this weekend.

I wouldn't go with just perennial rye, Bski. IME it has a tendency to look pretty cruddy (thin & scraggly), long term. Areas where I seed with (a high % of) perennial rye don't look good until something else fills in. I'd recommend a mix of perennials, with the rye no more than 40%.

FWIW, timothy has to have the highest number of seeds per pound of any grass. Mrs. Gallus snuck 50 lbs of straight timothy into the seeding effort after our excavating was finished this year, and I like the results. That stuff made a dense mat of tiny little sprouts in the area she put it in.

Tops and pond-sides of dams are harder to get grass established on than fill areas, I think because even a nice layer of topsoil there is sitting on top of heavily compacted clay that doesn't do squat to help grass grow.

Brettski, do you have any topsoil on the pond side of the dam? We pushed a few inches over top of the clay on our 3:1 slope and the grass grew but not nearly as well as it did in places with 6+" of topsoil. I could not get grass to grow in areas with clay only. I had a hard time keeping the straw mulch in place too. I saw a pretty neat product at the Farm Science Review that has a layer of chopped straw between two layers of very fine plastic mesh. I came in a roll about 15' wide and looked like it would really stay in place. In the old days, the highway contractors would spray on "strings" of tar to hold the straw in place. The grass would grow through an you'd never notice it.

How about placing a drainage tile parallel along the top side of the dam along the edge of the road, dumping in the the pond at both ends. It seems it would be less expensive and less of a maintenance issue in the long run compared to the ditches/berm. Scratch up the dirt on the pond side and spread some topsoil and concentrate on getting a the vegetation started. Mix in some winter rye or winter wheat with your regular seed. The regular seed should come up next spring if properly mulched.

I'm curious about why the road was pitched towards the pond. What about regrading the road to drain the other direction?

Theo,
I like the idea of mixing up the grass blends. I plan on inserting native grasses in the blend, similar to the balance of the areas adjacent. IIRC, the warms we used were blue stem, switchgrass, and Virginia rye. We used Timothy in our cool season blend and it came in well. When the time comes in the spring to plant grasses, I will run it by my NRCS guy and the seed vendor that provided the WHIP seeding for all the other areas.
-
Ryan,
Thanks for your input. The balance of the dam is in good shape with existing vegetation and one full season's worth of native grass and forbes growth. I don't want to shoot myself in the foot (again) and disturb a success story by scraping it up. We are gonna borrow topsoil from other areas of the property, scrape it up into his dump truck, and place it with the rubber tired excavator. I like the drain tile idea, but laying in a very short berm (I'm talking 3" - 6") that tapers back down to the existing grade of the roadway struck me as the simplest, natural method of diverting rain water. My biggest fear was creating an awkward "bump", but the more I think about it, we can groom it to blend right in. If we are going to go thru the time to build these run-off channels, I defintely want to make sure that they get ALL the business. The berm (or drain) would get it delivered. I'm going for the berm this round. The plan is two-fold. a) stop the growing erosion channels by focusing the run-off into prepared channels; this will minimize further extensive damage until spring. b) come back in the spring and do what I should have done the day the equipment left when the pond was completed...seed and mulch. Thanks to you, my friend, I have made a good contact with Conn-Tech....the geotextile guy that provided the beach matting. I reached out to him a few weeks ago to ask him about the straw matting. Yep; he's got it. The rolls are 6' wide and each roll covers 100 sq yards. They cost $50 each plus a nominal dely to a yard in our area. We will scratch up the remaining topsoil, fertilize and seed, and roll out the straw blankets.
-
Geedub
I can't regrade as noted in my reply to Ryan. Why does it lean that way? It does and it doesn't. The roadbed was excavated as close to level as an expert dozer operator can do. Dams settle and soils migrate with rain. It only takes fractions of inches to make water run one way or another. I know now that dirt work is not an exact science. Quite frankly, had I handled seeding the entire zone correctly in the first place, we probably would not even be discussing it. But, here I am.
-
Thanks again, guys.

Brettski, I must know where you can get this stuff. Is this correct? 1 dollar for 2 sq. yds. of the stuff? I thought air was not that cheap. I have a similar situation on a smaller scale. "Yep; he's got it. The rolls are 6' wide and each roll covers 100 sq yards. They cost $50 each plus a nominal dely to a yard in our area. We will scratch up the remaining topsoil, fertilize and seed, and roll out the straw blankets."

GW
I think earthen dams are engineered that way normally in case the water should overflow the top of the dam.
The water will move slowly across the top of the dam when the dam top is sloping towards the pond.
With the dam top sloping away from the pond the water would rush across the top of the dam, causing much more erosion.

Thanks Kent, that makes sense.

Hi Brettski, just a thought. Everything I have read here makes sense. But the most important thing is getting down something where the seeds won't wash. Top soil would be better but IMHO anything now would be good.

When ground is distrubed or you have something like the clay, non-desirable by most peoples standards weeds will be the first thing to come up. If I were you the first year or two I'd leave them be. Those tall weeds are natures way of healing itself. They will in the most part be annuals and have long tap roots that will add organic matter to the soil when they die. After the soil improves clump and turf grasses will crowd them out in the natural cycle of the land going back to what is the natural surroundings. In your case now natural along with what you plant seeds will just get washed down the steep embankment.

Consider rather than doing more excavations and dirt work. Use that cloth you mentioned, or hydromulch, or put down hay. Whatever you do you need to keep it from washing. I have seen hwy depts. use kind terraced row of plastic sheeting to slow down water on steep embankments. Or you could use stakes and string or wire. I don't know how much 300+ feet of hog wire would cost but if you staked it down on hay it would hold, first for the winter short term but also to hold seeds next spring. In fact along with planting seeds next spring you could go out into your pasture areas and take out plugs with a sharp shooter or post hold diggers and plant them in one row a few inches to a foot above the full pool water line. The plugs will have some good dirt with them and will grow in the clay, just not as fast, but it will. In a year or two you can pull the wire off and use it for something else.

I also agree with Theo, dont plant too much rye, mix in other grasses. If the rye is too thick in early spring it will crowd out the summer grasses will come up like little hairs almost. Then in late spring the rye will die out and pretty much mulch out any of your other seeds. You need to get a balance where the perrenial grass will get established and then they and the rye will kind of take turns.

I'm no expert on this and there may be other ways, but this method has worked for me, and it is relatively cheap, and not as labor intensive as it sounds.

In any case good luck.

I think you are over engineering it by creating your small berms and rock channels. I also don't like rye grass for anything but lawns. It's root system and the way it grows individually doesn't do very much, if anything to stop erosion.

If you go about building your berms and then the rock areas, it will become very dificult to mow and maintain. If you don't mow it, you will have other plants that will take over and create problems of thier own. Mowing is the best way to keep the vegitation under control.

Have you done any research into grass varieties for your area that have runners? Here, common bermuda is cheap and works incredibly well at stablizing the soil. There are dozens of types of bermuda that are used for everthing from golf corses, to hay and erosion control.

For ruts, it's best to just leave them alone until you can get some vegitation going. Then when that happens, you fill in the ruts so they are higher then the vegitation, and divert the water to the grass. This will stop the ruts from reappering and allow the grass to spread onto the new soil.

Until the grass takes hold and does its job, a quality silt fence will do everything you want without the expense of heavy equipment and loads of rock. Then when the grass is established, it's a simple job to remove the silt fence.

My farm supply store carries rolls of fabric with seed in it for stabilizing dams and new dirt work. He says he sells allot of it to the highway departments, that use it along the roads when they do work. My neighbor bought quite a bit of it for his dam when we received almost 4 feet of rain in four months. It worked great, but now he's having issues with mowing and how steep he made his dam, but that's another story. LOL

My dam is 4:1 up to the water line, then I cut it allot more shallow to between 5:1 and 6:1 for mowing. I try to catch all the water on my dam that I can and have it flow into my lake. It's free water, and I want all of it that I can get. hahaha The bermuda grass does an amazing job of moving water without any ruts developing.

This picture was taken just over a week ago. I seeded the dam last November and had about a month of growth before winter hit and it went dormant. It remained that way until late spring, then it's been growing and spreading out all summer and fall. I'm not 100 percent covered, but I sure am close to it.

Eddie

[img][/img]

That slope is so great for mowing, it is not obviously a dam at first glance, Eddie.

How to:
http://www.pondboss.com/forums/ubbthreads.php?ubb=showflat&Number=74464&fpart=1

Great post and photo, Eddie Walker.

Yep, agree with Burger. Thanks guys.
To address some of Eddie's thoughtful input...
I will use rye. It grows well up here and is fairly drought tolerant. It will be part of a blend, tho, that includes a good dose of native grasses and wildflowers. I am sure that wheat or some other cover crop will also be used to hold while the natives and forbs take hold. Remember, we are in very different climates. Also, most of this area is a steep 3:1. Nothing is going to take at this time of year up here. This spring is my next/best opportunity.
Regarding mowing, the plan will include only prescriptive mowing to get things established. The idea here is an area that looks like Mother Nature took over. If the entire dam is overgrown with native grasses and wildflowers, my mission will be complete.
-
The ruts. This one is still kinda difficult. There is a couple of channels that are serious. It will be very difficult to impossible to force these areas to vegetation. It's one of those things that you have to see to fully understand. Once again, the climate thing comes into play. Up here, the exposed soils freeze solid as a rock during the dead of winter. The lower portions of a washout will also freeze, but not deep. The perfect storm occurs when we get a few days of thaw and then a good rain. All the water is refused by all the top/flat surrounding landscape. It heads right for you-know-where. The bottoms of these run-offs are now thawed because they were never deeply frozen solid and the 2-3 day thaw softened them. The result is killer erosion, straight down the center. If that occurs in these couple/three areas that have already suffered this, I could have double-trouble this spring. The decision to create narrow rock spillways covers all the bases and should be the end of it. In time, grass and weeds will likely grow over into the rocks (rooted into pockets of trapped soil) and they will all but disappear.
-
That is a v nice pic of your baby.

Bski I still got some of that Johnson Grass seed if you need it.
Just kidding.

“For ruts, it's best to just leave them alone until you can get some vegetation going. Then when that happens, you fill in the ruts so they are higher then the vegetation, and divert the water to the grass. This will stop the ruts from reappearing and allow the grass to spread onto the new soil. “


I have to side with Eddie on this one. I agree with him you are being a KOOK again. I really don't thank in the short term you have any real worries of dam integrity issues. The ruts you are getting are common place in west Texas were they build ponds and don't even concern themselves with putting top soil back on the Dam. They have been there for 50 years+ and counting. If it were me I would save the rock to line the waterline of the dam too prevent wave action erosion. Any further erosion this winter should be minimal by next spring. Another words you can easily fill in the ruts when it’s time to till and seed next spring. I do agree about getting rye grass on there now if you can as a temporary fix or deterrent. If anything just put a pile of dirt at the top of the ruts on the worst areas and force the water elsewhere for awhile until you get it fixed. It’s your baby so do as you wish and good luck. I wasted 1500$ on Bermuda seed the last couple of years cause our local farm stores have no problem selling you an 800$ bag of bird seed and calling it grass seed. I have gotten zero germination twice when trying to get Bermuda started on a 10 acre patch. The first time may have been lack of moisture but this last spring I seeded it in the rain and it rained on it for 6 days straight.

Hey Ski, if Rocky runs out of Johnson Grass seed, I could cut you a sweet deal on some ragweed seed. Dang near guaranteed to grow.

i got a good deal on thistles....star, milk, and cow.

FWIW, when new ruts developed around my puddle, i basically allowed them to be the "new" drainage. i let them deepen some (all the while watching stuff erode into my new clean pond....it was tough to watch) but then lined them by hand with a relatively thin layer of concrete. if you dont want bare concrete showing, you could "tile" them w/ some small rock before the concrete sets. the second year through they worked great and erosion has basically stopped. the hydroseed job i did has filled in, and you cant even see them now.

thanks, Dave...that's pretty much the plan, but lining with erosion fabric and (a D.I.E.D. rockhound drum-roll please)....filling it with ROX!

DONE
-
We hired a local excavator that came recommended. $60 per hour, using a rubber tired front-end loader/back-hoe and a dump truck (the dump truck came into play when we had to move larger volume of rock from the stockpile). I had another guy bring in 20 tons of the oversize rock. I was able to call the guy that owns the pit and ask him to send product that contained minimal sand and clay; just rock. He said that he would use the rock bucket to load the tri-axle. $210 delivered.
We cut 3 run-off channels along the dam. Each was about 3-4 feet wide and 12- 18" deep.

-
D-ski and I cut the geotextile fabric from the 12' long roll he brought and laid it into the trench. We would hold the edges of the fabric up with shovels from each side as our dirt-guy dropped in the rock.

-
We also re-channeled and rocked the pond side of a feeder culvert that gets pretty good action during decent rains. The last channel was a substantial run-off rut from the building pad that ran down near the launch. This one was about 25 feet long and had a nice little bend in it. It looks cool with the rocks in it; kinda like a dry creek.

-
We selected an area to borrow soil from to build the berms. It was far enough away to be out of site, at the edge of the woods and at the base of a run-off draw. I told our dirt-guy to stay in one area and create a small vernal pond (Lance aka; beaverboy will appreciate this decision...Bing too). So, now we have a 10 or 15' x 24" deep mosquito laboratory. Hey, who knows. Bruce will probably have me growing FH in it.
-
We manually raked down the berms to dress them a little, yet leave them high enough to allow for settling. I cast fertilizer and winter rye on 'em and lightly scratched it in with a leaf rake. We are expecting rain and warm temps this coming week. I know that winter rye puts out some extraordinary performances in the cold weather. I just want it to hold the soil as it settles out for re-seeding in the spring with a more permanent blend.

-
(EDIT)
Oh yeah, we had some extra rock and a couple ruts on either side of the exit end of the 18" dia. spillway pipe. I planted grass down here that did take fairly well around the pipe, but it is located in an area that catches run-off further above and either side above the pipe was wearing away. So, rock me.

That looks like it ought to work (hold in place in the presence of runoff), Brettski. The rocked-in swale by the boat ramp looks like it belongs there, landscaping-wise.

I'm trying to half-remember and half-judge from the photos - you're like, what, 5 feet below full pool right now? I expect the rock below the overflow will get some serious use by Spring if not a little earlier.

We're about 3-1/2 feet shy of spillway. I'm kinda depressed and a little concerned for the water level. We hit 25" short after the last spring rain drencher. Since then, it has fallen and risen (mostly fallen)with sporadic rains. This is all new to me, so I'm trying to temper my concern by chalking it up to a)new pond, new soil saturation---b)fairly dry spring and summer---c)evap---d)surrounding run-off is sucking up my precious feedstock.
-
If this is another wet winter like last, we better be splashing those spillway exit rocks or I have a problem.

You're fine. We're all low in the Midwest (not the North Central, Bruce) states this year, even if we were full pool coming out of Winter.

-
-
I just ran thru this thread again, and forgot to address Rocky-T's callous, demeaning remark. Allow me to respond:

Rocky, jeez the word Kook is not very politically correct. We prefer the term Reality Challenged.

Tejas vs. Cali. We have more kookiness than reality challengeness.