Pond Boss Forums POND CONSTRUCTION Building a dam Pond Spillway

I'm new to this forum, so this topic may have been covered. I'm building a 1.5 acre pond with a watershed of approximately 7 acres of woodland. My contractor, who builds a lot of ponds and lakes, says that most of the problems he sees on dams center around the overflow pipe. He suggests eliminating the overflow pipe in favor of a spillway only. I think the forumla is: 1/2 the watershed area divided by 2 + 15 feet. In my case 7 / 2 = 3.5 + 15 = 18.5 ft of spillway. Any thoughts on this one?

Welcome to the forum, Git1Fiddle.

Congratulations on the new pond! Sit tight, some experts on calculations like this are sure to be on their way soon. Few initial thoughts:

A 1.5 acre pond with a watershed of 7 acres and precipitation of around 40" annually [right?] to me seems as though it won't be flowing through most of the year, but that's my WAG.

An overflow pipe is a routine aspect of the job. IMO a qualified contractor shouldn't consider implementing a overflow pipe as a challenge - at least if he's confident in his abilities and has relevant experience. As we know it's always wise to seek a few contractor's opinions/quotes/ideas prior to making any commitments, and I recommend you do that here. A good place to start is to contact your NRCS and request some pond builder/engineer recommendations. Sometimes they're reluctant to provide that information, but it's worth a try.

Again, welcome to the forum. I'm sure some experienced guys will be along soon to guide you capably.

well i love overflow pipes they are the best thing to happen to most ponds. i'm not familiar with your dirt but here in osage county oklahoma i have never put a pipe in a pond for the nrcs with less than 20 acres of runoff and i say never except once it shed 15acres and was spring fed. the nrcs was afraid that it would keep spillway soft and cause erosion.they are very particular not to disturb the grass on spillway during construction of these ponds. i havent had any problem with these ponds but we did spend a lot of time picking the sites. we looked for good vegetation growing on spillway area if you dont have that i would recommend a pipe it shouldnt take a very big one thou. the 15 acre one has a 6" pipe no riser just a hood cut on end of pipe with 2 anti-seep collars the pond has 3' of freeboard is 5 years old with no sign of erosion on spillway. one other thing we had in our favor was that these were all for big ranches so we had a lot of area to pick our sites from. so if ur worried about it you should be able to get 70' of 6" pipe for around $400 and get it welded up with anti-seep collars for another 4 or 500 bucks i would think. just bought 140' of new 6" for a bottom drain of a big pond for 6.90 per ft. just given you some examples hope it helps and all these ponds had 10' wide spillways with 2' of freeboard

We tried overflow pipes 4 times and finaly ripped it out for a rock spillway best thing I ever did.
I now have stable water levels. muscrats don't dig around the pipes. Don't have to deal with leaks around the pipe anymore. The field rock was free. I have a huge watershed in the early part of the spring and it handles the water well. Spillway is about 6 foot wide

Thanks for the posts, gents. A little more information. The pond is being built in a wooded area, so the watershed of about 7 - 10 acres should provide a good clean runoff through undisturbed woodland. The dam will be built across a natural draw, and will measure approx 50 yards across by 15 ft high. The spillway will overflow across an undisturbed ridge on one side of the damed up draw. Hopefully we will have some natural woodland vegetation covering the spillway, but I'm leaning toward a nice shot rock rip-rapped look at the mouth of the spillway. Our plan is to have the spillway wide enough where it will carry the water flow in a heavy rain to a depth of no more thantwo to three inches. Another feature my contractor suggests is digging a 12 to 15 foot basin where the watershed empties into the pond and then coming up to a 6 to 7 foot level and then a gradual deepening to approx 15 feet at the dam. He says this will act as a "sendiment pond" within the pond and should increase the life of the pond.

I disagree. I like overflow pipes and want a spillway for only a momentous event.

A pipe is a problem if you do not have an experienced or knowledgeable pond builder. Get a new pond builder, have an experience pond builder help him, or don't build a pond. Otherwise you'll likely be posting here soon requesting help in fixing your pond. If the dam is built correctly and wide enough, muskrats etc. are not an issue. Sorry to be so blunt, but that's my nature,

"Sorry to be so blunt, but that's my nature"

Yeah, RAH, expressing your opinion is kind of the idea in a forum, that's how we learn from each other. And there are certainly varied opinions in this thread about the use of an overflow pipe in a pond the size I'm building (3 are OK without the pipe and 2 are definitely for the pipe). One thing for sure, when I read the forums on dam repairs I see that my contractor wasn't far off the mark ...there's an awful lot of people dealing with leaking and collapsed overflow pipes. I'll continue to do my research and see what other posts show up here.
Thanks guys....

Make that "3" for the pipe.
soils with decent clay content + proper compaction and installation + suitable trash guard = restful nights of sleep during torrential downpours.

I'm new to the website too, but we built our first ponds in 1992, and now are up to 18, all with principle spillways being overflow tubes. I agree with some of the prior comments about questioning your contractor. I've had 3 different contractors and they all put in fine tubes. I'd suggest at least a 10 inch tube, to minimize problems with trash plugging it. Every once in a while we have cattails plug even a 12 inch tube in the spring, so maintenance is important. Your secondary spillway is also called an emergency spillway for a reason-- it is only to be used during 25+ year storm events. In addition, this spillway should be vegetated with a sod forming grass that will protect the soil in the event that water does flow though it. Trees on the spillway (and moreso on the dam) are not good, because when the tree eventually dies and the roots rot, they form perfect little channels to breach your dam.

Your contractors idea about building a deep pool at the inlet, then a higher ridge before dropping into the basin near the dam might sound like it will work. However in practicality, if you have sediment enter your pond during a heavy rain it won't settle out in the upper pool. Your best bet is to make sure you have good vegetation cover in the watershed. Otherwise if you finances allow, you might consider a series of ponds in a single watershed, if you have enough water.

Back to tubes, we've used heavy grade sewer pipe for several ponds, covering the outlet and inlet with sections of galvinized corrugated steel to prevent UV damage to the plastic. Rent a tamper and be out there when the pipe is installed. When you fill in the trench, the most critical area is below and to the side of the tube, so fill slowly and pack often. It's easy to get in a hurry and fill too fast, then you could have poor packing below the midline of the pipe. Get good quality antiseep collars and carefully install them. Then we take heavy plastic sheeting and put around the tube on both the inlet and outlet, and cover with field stone.

Well said Bill.
I think most pipe area leaks come from poorly compacted soil around the collar. If I ever need my spillway, make that my emergency spillway, I want it to be in good shape.

From the ponds that I've seen with properly installed overflow pipes, I recommend them instead or relying on an earthen spillway. We're talking about years and years of usage, and soil will erode, no matter what vegetation is growing on it. I am of the opinion that if you build it right, you only have to build it once.

Git, Where in Missouri is your pond located?

I ask, because if your pond is in the Ozarks, it is highly unlikely a 7-10 acre watershed will support a 1.5 acre pond, and even less likely to provide enough "flushing" of the old water to maintain a good water quality at the depth of the pond. In the Ozarks, you'll need 15 acres of watershed for an 8' deep, 1 acre pond. For the size of your's, a 30 acre watershed would be about the minimum in an average rainfall year.

There are a lot of dirt movers and tree clearers in Missouri, but precious few pond builders and I would hate to see you spend a few grand to build a pond and 20-30 grand to fix it later.

Rainman...
Pond is in Callaway County, right in the middle of the state. We finished digging the pond at the end of September and I'm about 2 feet from full... just from fall rains and winter snow. By my calculations, a 1 inch rain raises my levels by 1 to 1.5 feet. Of course we had some hellacious snow this year, that last one around 18 inches. I ran a depth finder off my kayak this afternoon to take a look at our structure from the top to see if it looked the same as when we were digging it. Max dept is approx 30 feet at the center, with shelves at various depths (15 ft, 8 ft, 6 ft etc) and some stretches of rocky, sandy substrate at 2.5 to 4 feet for spawning beds. We stacked oak stumps with root balls for cover and made some spawning holes for our catfish. I stocked 200 bluegill, 50 redear and 2 lbs of fathead minnows in October. The bass and catfish will go in this spring.

I'd like to know more about the aeration. My surface area ended up being just under 1 acre...any suggestions for a system? Also, are you suggesting that if I aereate the pattern should be deep in the summer and move to the shallower water in winter?
Appreciate your input.

Will the fish that you stocked in the Fall have a chance to spawn before you stock the LMB and CC? (are they big enough to spawn?) and what size are the LMB and CC that you are planning on stocking?

esshup...
I'm following Missouri Department of Conservation recommendations on stocking which is forage fish (3" BG and Redear, fathead minnows) in fall followed by LMB and CC fingerlings in late spring (May). If I understand the recommendations, the fingerling bass will feed on zooplankton and insects early on giving both minnows and BG ample opportunity to spawn.
My goal is a balanced population for all around recreational/table meat fishing...mostly with a fly rod. I welcome your suggestions...

git1fiddle, Per your statement:

"I stocked 200 bluegill, 50 redear and 2 lbs of fathead minnows in October. The bass and catfish will go in this spring."

Was this based on a conscious decision or just coincidental with the timing of completion of your pond?

I plan to stock Bream in the Fall, bass the following Spring but that means I have to WAIT. I don't want to but that seems to be the prevailing advice of sources other than this site.

Just curious. Thanks.

Fly rod. You'll be a big hit with George1. He's a fly fishing extraordinaire!

I think you will be a little light in your stocking numbers. Typically, it's roughly 1,000 BG/sunfish per acre, 80%/20% BG/RES

I feel that the LMB will start eating any fry that is spawned the first year and not let you reach your forage numbers, resulting in less than optimal growth for the pond. Personally, if it was my pond, I'd stock it heavier with forage, trying to hit the 1,000/ac number. If funds weren't available to do that, and you kept the forage fish numbers the same, then I'd wait 2 years to stock the LMB and CC.

Are there any plans for supplemental feeding the fish?

You are correct in aerating deep for summer and shallow for winter. Deepest hole for summer, 25% depth for winter.

We probably should break this up into 2 different questions now and move them to the appropriate forums to get a broader viewing base. Aeration and creating the food chain. It might get lost in "building a dam"

Git glad to have you on board as you can see this place is a lot of fun. Lots of good advice.
The spillway pipe is used to protect the emergency spillway. If you have a good place for the water to run around your dam then it is not needed. This has as much to do with the change in elevation as the venation. IF THE WATER WILL FALL FROM THE POND DOWN FIFTEEN FEET TO THE CREEK IT WILL TAKE A LONG SPILLWAY WITH GOOD GRASS TO NOT BE A PROBLEM.
There has been a lot of good info already—I will only second some of it.
Use good thick plastic.
Install it properly. The hand packing is the key.

Git, I sent you a private message...As Kiko asked, are you stocking due to the timing of the pond building or waiting?

There will be little if any growth of your forage fish over winter and without a good food chain base, many may lose size over the winter or even die from starvation. We have a good Conservation Dept in Mo. but some of their ideas can leave you scratching your head asking "why do they say that?". A fall forage stocking with a spring predator stocking has virtually the same results as stocking everything at the same time in our climate.

Git, esshup is right about your stocking being very light on it's numbers, but your area does not have the fertility to feed 1000/acre rate...500 more would be better for BG and about 150-200 more Redear.

Essentially, you want 10 BG for each bass...You may want to add another 10 pounds of Fatheads and maybe some golden shiners this spring when the bass are stocked.

OK, guys, I got approximately three sets of numbers going and a couple of timing recommendations...let me lay them out (numbers per acre):

esshup: 1,000 forage fish (80/20) BG/RES...100 LMB?
Rainman: 700 BG (add 500 to my current 200) and 200 RES (add 150 to current 50)...100 LMB

Mo DNR & Nebraska DNR: 250 BG...50 LMB

Timing: I'm timing my stocking based on recommendations from Missouri DNR and Nebraska DNR (because they are a little colder climate) which both recommend:
BG in fall...LMB fingerlings in late spring of following year. Most fish farms hold "fish days" during both of those stocking periods since many folks follow the DNR guidelines.

If I understand correctly, esshup suggests waiting two years before stocking LMB and Rainman recommends (and I'm just inferring from what you've written about forage fish not growing or spawning during the winter) waiting another year.

Alright, that gives me info to process...thanks guys.

Git...The MO and NE guidelines are about 50 years old and frankly...wrong....MDC publishes general guidelines, but does not follow them in the public lake stockings and opt for the 10:1 rate. Your pond has a finite carrying capacity and improper stocking or overstocking can stunt the fish or make disrupt the original balance of the predator/prey relationship.

BG will spawn several times per year and be the main food source for the Bass...The best proved stocking ratio is 10:1 Your RES grow slower, yet larger than BG and are there to eat snails that host the grub parasite...RES only spawn once annually and won't produce an adequate forage source. They serve a specific purpose in the pond's ecosystem and are a great "unexpected" catch plus they're great table fare.

I suggested a 75% stocking rate because I know your pond's general location and the surrounding grounds are a little less fertile than needed for stocking 1000 BG. I would not stock 100 LMB in a one acre pond in your area....Your Bass will spawn in a year and over-populate faster, grow considerably slower and require more intensive management to prevent/correct.

The fish CAN be stocked together or separately, but overall growth is going to be better for all species if forage fish are stocked one growing season before the predators...ie..BG stocked in Spring and predators the following Fall of the same year...CC, if used, can be stocked with the forage as they are a poor predator and make no notable impact. Feeding a good quality fish food such as Aquamax can over double the first year growth also.

2 lb of FH (that's only about 5 FH for each BG to eat) with the BG won't be able to reproduce enough for good growth rates on either the BG or LMB when introduced. If it were my pond, and it's not, I would add another 10 pounds of FH asap and 10 pounds of Golden Shiners. The FH will be gone in a year or two after the bass, but the shiners will likely establish a reproducing population and add another forage source for your BG, RES and LMB.

After one fish farm was sold a couple years ago, IMO, Missouri no longer has a good quality fish farm for pond owners, but that has only made me busier...lol

Bottom line is... It's all about what YOU want from your pond and what YOUR goals are. A puddle can grow fish but it takes an informed owner, quality fish stock and good management practices to create a quality fishing pond for generations to come....IMO, the MDC program gets an average MO pond about 5 years of decent fishing of a few medium sized fish before stunting badly.

I always ask clients why they spend $1000's on building a pond for fishing, then skimp or cut corners on what all that money was spent for to begin with...the fish. We closely check out our builder's qualifications, research and plan the pond extensively, create great habitat for fish to thrive, then stock whatever fish are readily available of an unknown quality or source at rates that are questionable and then wonder what went wrong a few years later with what all that research was intended to create.

Thanks for the detailed overview, Rainman, you really took some time. The FH and Golden Shiners will be an easy additon and I'll plan on getting on those soon. But rather than add more BG to the pond, maybe I introduce only 25 LMB...that gives me the 10:1 ratio BG/LMB ratio, and maybe alleviates the overcrowding issue in future years. You know, I like a nice slab bluegill cooked up probably better than a bass, though the bass are more fun to catch. Will the 10:1 stocking ratio allow for some good sized BG and RES, or do you sacrifice size for the benefit of larger LMB?

Your thoughts on the above would be appreciated

Git...You could go that route. Problem is that the pond volume you have may allow you to instantly become BG heavy because the low numbers of bass will have a larger area to hunt, allowing too high of a BG recruitment.

The 10:1 ratio will usually provide you with a lot of medium large BG (1#)and several 4-5# LMB and even a few lunkers of each.

After the second or third LMB spawn, you'll want to remove any skinny bass caught and maybe make a slot size like 8-12" bass that you remove 100 per year. Keeping records of fish caught/kept will help you understand the dynamics developing in your pond to prevent any overpoulation and stunting.

Some of this may seem a little overwhelming and extremely complex. In many ways it is, but you'll get used to it pretty quickly and it becomes second nature. We put fish in expecting one result and often ignore or never think of the many unintended consequences. We can want anything...getting the fish to agree with us is tough!