Pond Boss Forums POND CONSTRUCTION Building a dam Principal spillway logic

I have once again conferred with my contractor and one of the subjects was the principal spillway. The spec's of the project: approx 5 surf acres, approx 35 ac/ft, 60 ac of drainage (about 40 ac of which is row crops), 36" avg annual precip.
The original plan was to utilize 2 separate 12" dia spillways. They will run for a considerable distance thru the valley we are filling in downstream of the dam. The overall spillway tube length will be 260 ft. The idea for 2 separate spillways was to cover the potential of one clogging, particularly since the pond is surrounded by heavy timber and I won't be there to watch it every waking moment.
The new thought is a hybrid of improvement with some savings. The improvement will be going to a single 18" dia pipe. The savings will be with material (likely minimal) and installation time. The 18" pipe will allow an even larger area of flow than a pair of 12's. The logic is that it if one 12" pipes is gonna clog with sticks and leaves/crap, the second one is probably not far behind. An 18" dia pipe will be less likely to clog, compared to a couple of 12's.
This all makes good sense to me. Kick back some thought, pondmeisters.

Personally, I like the odds for one 18" pipe clogging AFTER either/both 12" ones. Either way, clogged pipes and extraordinary rain events are what secondary/emergency spillways are for. What's your plan for your emergency spillway?

ahhh, yes...the emergency spillway. This is just one more facet of the engineering where I tip my hat to the guy I am paying to make this pond happen.
Like many ponds, the emergency spillway was planned to run around one end of the dam. The inflow/outflow calc's indicated that it may very likely never even get used...unless...the principal got clogged.
About 6 months ago, I got a brainstorm to divert about 5 or 6 acres of adjacent run-off into the pondsite. It would be reasonably easy, but would mean dropping the level of the pond by 24". Why? Because this new-found drainage was that close in elevation to normal pool. I started a thread here to weigh out the better decision of 6 additional ac of drainage or 2 additional ft of depth over 5 ac. pond. When I shared the thought with my contractor (who, at that time, was unaware that I had discovered the additional 24" of depth within the pond basin), he thought about it for a night and called me back. He says take the 24" of additional depth and we will put the emergency spillway at the area where you were gonna bring in the 6 additional ac of drainage. The boss and I immediately headed out to the site with the laser level and tripod and started shooting thru the woods to verify the potential outflow at this point...it will be perfect. The biggest change and only work that must be done to facilitate this emergency is to put a 20' culvert under a section of the new driveway. The crowning jewel, tho, is that it puts the emergency spillway at the opposite end of the pond, some 700 feet away from the dam.
Pretty slick "out of the box" thinking...makes it a little easier to sign the check.
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(edit; found the thread about 24" add'l ht. vs. 6 ac watershed: 24" vs. 6 acres thread )

Brettski,

Why not use one 12" since you have the emergency spillway? My other thought is that if one 12" dosent work, use one 18"...another thought is to use a vaccum breaker (or syphon) design and avoid clogs altogether.

My thinking is LESS holes through dam = better.

Gator

60 acres of drainage sounds somewhat skimpy in the midwest for that pond size. Is there a spring that runs through the area in the summer or a continous high water table?

But what do I know, I'm not a pondologist

agreed...somewhat. It is about 1/2 the ideal volume based on local stat's., but definitely not a pond deal-breaker. The payback for waiting a little longer for fill-up is the peace of mind when a 10 year rain does occur.
nope...but tons of killer clay to hold what juice is gonna be there. That, and it is a bowl completely surrounded by tall timber so the wind evap. is minimized.

DAM!!!

About 80% of the dam completed. The white PVC strainer core is barely visible at the toe. The dam is a few feet short on height and both ends are lower still to allow circuit-movement of soil to fill in the valley down-stream. It's time to start gettin' serious about placement of the primary spillway pipe.
The clay is simply extraordinary. Once the 2 - 3 ft of topsoil was removed, the subsoil is gold. The entire dig zone in front of the dam is awesome with killer clay. My contractor noted one small zone nearby that had a vein of lesser quality, but even that was reasonable.
(The "boss's" street truck is outta place here, but meets the dirt challenge as long as it doesn't rain)

Pretty freakin' exciting, ain't it!

Any ideal how deep the "killer clay" goes? Looks exciting here!

Hey Ahvatsa...good to hear from ya
We buried a buncha root balls in the valley behind the dam and well down-stream. The hole was about 13-14' deep and it showed no signs of stopping. Before I even purchased the parcel, I pulled the DNR well drilling records and got 3 recent wells, all within 2000' or so. They were consistent, reporting the first 30 ft is blue, yellow, or brown clay.
...Sir Gallus delivers a report from the Ohio side of the Round Table: Yes, sire, indeed it is!

Brettski

It's amazing to see your progress and how nicely it's all coming together. Some people just get lucky and it happens that way, but you are making your own luck!!!

Are you still building a pier? I remember a discussion about different ideas on how to do it and I'm curious what you've decided and when you'll start work on it?

Thanks for the pics,
Eddie

Brettski,

Nice work on the dam, great pics. I like the clay!

Gator

Thanks gents...it is truly an awesome blessing that we are experiencing. I, unlike the skillful and tenacious DIY'esness of guys like Eddie Walker and Meadowlark, rely on the performance of a 2 man crew that does this stuff for a living. As Eddie mentioned in his "Building My Lake" thread, it is rewarding when the vision turns out better in reality. My contractor does exactly what Eddie does...thinks about how to take my vision and move it up a couple more notches. I have nix'd very few of his suggestions. One outstanding idea was to cut back into the trees another 30' and add a road that starts at the boat launch/bldg site, follows the perimeter, tucks into the woods at a peninsula, then pops out the other side at the dam, goes across the dam, and comes back about 1/2 way the length of the pond, terminating at an open knoll where the sand beach will be located.
A pano-shot from the front edge of the proposed yard at the building site. Launch is immediately left, out of frame. Road begins there and follows the left perimeter. Dam is just left of center, around a slight bend, some 700 ft away. Knoll and beach at open area, upper right. The balance of the perimeter at the far right is going to be left shallow 3 - 4 ft. About 1 - 2 ft deep will run up into the timber. This is designed and reserved as a wetland zone, perhaps a half ac total.

...oh yeah...the pier(s)
Yep, I just got back from Menards. They had their stainless steel lags/bolts on sale...$300 worth. I submitted a drawing to a metal-fab shop near work; they are laser cutting and bending my stainless post support bases. I nix'd the Simpson pre-fab units as too expensive. My design will be well over-engineered for strength and still cheaper. I gotta do a balancing act with pouring concrete and establishing at least the framework of 2 piers before water finds me. A bitter-sweet thought...I want rain, but not until I'm ready, please. Being the drier days of Summer, I think my timing will be as good as it's gonna git. I imagine, tho, that it's gonna take a long time to fill 'er up with 60 ac of drainage. Yeah, right...then I think about PFF's and Rockytopper's overnite sensations!

Brettski:

Nice "pano" - pieced together, I presume? Either you are very selectively squeezing the inside of the two frames to eliminate the distortion I always get (and nicely done, I must say), or like another Illini, the late Senator Paul Simon, you favor the bow-tie. I may have to figure that out (the anti-distortion, not the bow-tie).

When we had Dell deliver the PC some 3 or 4 years ago, it came with some software junk, alot of which I don't care about nor use...except...the Canon Photo-stitch program. As I sit here peeling a banana and hanging from my cage by my tail, I rest asssured that even I can perform outstanding photo-stitches. The bowtie thing is an option for wide angle (suddenly I have a taste for pasta... ) Yes, it is a pair of panned scenes.
Pardon me now as I resume tossing and beating this Samsonite suitcase.

Awesome thread Brettski....great lookin clay, I am impressed at your level of research on the property in the first place....you should be very proud despite the wallet woes......, and now, so close to seeing the dream completed.....very exciting.

D.I.E.D.

Brettski,

Remember, I've got dibbs on a visit to the site.

Don't worry about the 60 acres...don't look back, only forward. It's going to be one great pond! (Even with those holes in the dam )

Brettski :

Remember that you were/are going to do a thread on the entire process. You may need to cut and paste from this thread to the other thread to make it complete. Great job with the pics but even more so on the pond methods/planning and thread/story concept.

Meadowlark...the gate is open for ya anytime! I know you luv the dozer stuff. The guy runnin' the dozer is actually a retired dirt guy that can't get enough...done it all his life. (I imagine the pay package is fair incentive) Red makes that D-6 dance...not one wasted motion. I mean he pops that thing around like he's attached to it. I know he would learn ya a few things, be happy to do it, and I would double his pay knowing the value of the edumacation.
John, the other guy and the boss, typically runs the excavator and the scraper (E-mover). It is nice these past few days to finally see volume production of dirt movement. The scraper is now the main player. It's an older model (1984?), but John really takes care of his equipment. It shows...and still delivers.
...and, finally, they keep cuttin' and scrapin' and the clay won't stop...a shot after many scraper passes in front of the dam:

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Ewest...yep, you bet I will compose a collective analysis and summary into one thread. I think it will be a nice Fall/Winter project. If it will help somebody else like you guys have helped me, I am obliged and deeply humbled.

Brettski- It is so great that your dream is finally coming true. Keep those great photos coming.

Brettski,

I'll second Ponds. Keep the pictures comeing!!!

The picture of the dozer is really nice. Do you know how much dirt he's moving? Mine is rated for three yards, but I have a different type of blade. That one looks like it's doing twice what I am!!!!

Thanks,
Eddie

Brettski what is the next step after pond construction wrt fish , if any ? Now is the time to plan and fix the pond bottom to meet your fish needs , if any. For example if SMB then look for some chunk rock/large gravel/broken up concrete and think about where to put it. Other structure needs and desires (like your tires) are much easier to do now now with the equipment than later with water. Same for pond bottom humps , cuts , rip-rap and ledges etc.

Another question are you putting a pier next to your beach ?

eddie_walker the D6H pushes about 7 yards and is 165 horsepower.

brettski, you are going to have a beatiful pond. I can't wait to see pics of how the emergency spillway comes out.

Ewest...
Yes, indeed...da fish. It is no mystery that I come to this forum with very little fish background. My drive was nothing more than creation of a beautiful water feature. I always had plans of stocking, but had no idea of the depth of the art and science until I arrived at PB. Quite simply, I had never walked a mile in the shoes of a fishing nut. Now I realize the value and will endeavor to do the right thing.
I expect that I will resume where I left off as a boy, fishing on ocassion, now and then. This place will be a "vacation home" situation, so I need to select a viable, self maintaining pond stock. Based on all I have absorbed, I lean toward the standard LMB, BG, CC mix with step one being FH forage base establishment.
The pond will run about 15 ft deep at the dam and about 11 ft at the opposing end. I plan some ditches and humps. Cuts into the banks creating ledges that drop off in 2-3 ft increments are planned. Yes, the tires will be assembled to create "jungle gyms". I have the materials waiting in the garage for about 6 PVC trees cemented into concrete based buckets. Hopefully these turn out well and I have the time to make a bunch more before the water backs up...?? I never gathered the wooden skids. I am having a wierd problem with their actual need for FH spawning. There will be a 1/4 ac zone of wetland depth that I expect will over-grow with vegetation...planned that way. Is it fair to say and expect that this will provide the natural objects that FH are looking for to attach eggs? If not, I could still get the skids and sink 'em in there. If they are needed, how many?
Yes, there is a pier planned at the beach area. I remember your point of it's logistical value WRT the swim area. Besides, the beach will be some 1/3 + mile away from the building site via the perimeter road. If I decide to use the Liberty Ferry to get there, I will need a place to dock her.
JBL...
The emergency spillway winds up being the lowest tech, lowest cost facet of the entire project. As luck would have it, the lowest natural bank on the entire perimeter is right at an out-flow area that works. We had to remove a swath of trees about 40 feet wide, 50 feet deep into the woods, and cut down the bank about 1 ft.....finito.
I s'pose I better get you guys kickin' in ideas v soon. Bring it on...thanks.