Pond Boss Forums INTRO Questions & Observations Spillway Goof / Rookie Surveying

Last weekend, I dug a 40 x 70, 8 ft. deep pond in a low spot on my property. A day after I had finished digging, I received 2.5 inches of rain, which took the pond from empty to completely full. To my surprise, I found out that the spillway is 6 inches higher than the inlet!

...I guess that's why you don't see many real surveyors using a string level like I did.

The pond receives water from a very gentle slope, and the planned spillway is also on a gentle slope, so I can't just dig a little to solve the problem. Here are the possible remedies I see:

1. Bring in several truckloads of fill and build up the inlet area so it is higher than the spillway. This is probably the best way, but it will be expensive and time-consuming.
2. Create a broad, general overflow area around the entire circumference of the pond to give the overflow space to evaporate/absorb.
3. Run electrical and buy a float-activated pump to send water up and out the spillway when it reaches a certain level.

Any opinions/ideas?

Follow the water. Water always seeks the path of least resistance. We have actually designed ponds where the inlet is also the outlet.
The pond reaches a certain level, can't rise more, and overflows naturally, the same way it did before the pond was built.
Your other best choice is to build up an area where water has no choice but flow where you want it. A levee, or a dike allows you to manage water flow.
The best answer is to watch the water, enhance it's current flow route and leave it be.

Bob,

I'm glad you mentioned that you had designed ponds where the inflow is in the same place as the outflow. That is exactly the case with my pond. It reaches a certain level and the inflow area floods.

When you designed such ponds, how did you ensure that the inlfow area didn't stay perpetually underwater and become a soupy mess?

Bob,

Your advice proved to be prophetic. We got another 2 inches of rain, the pond hit a certain level, then blasted through a piece of the surrounding berm to tell me exactly where the spillway needs to be. I'm going to obey its direction and work with the natural flow.

i think #2 would be a bad idea. provides too much swampy area. i really prefer sending the water somewhere else in a somewhat "focal" manner, or a given space instead of widespread areas. CONTROL the water, or it will control you!!! also, have you called your soil conservation service guy, i think he'll come out and "shoot your lines" for free, rather than using a string method!! if he says it will be a while, bribe him!!! if you continue having too much overflow, build ya a bigger pond and take advantage of your water source. bigger/deeper whatever, just try to hold as much of that water resource if you can. good luck . mark

When we design an inflow/outflow area in the same spot, we don't make it wide. When the creek flows, it quickly recedes. But, the pond stays full. So, we usually place a short berm, slightly higher than natural ground level, where water will overflow, then recede. Other times, we lower a short section of the creek bank, at a slope, where water won't stand as long as the creek recedes.
Where your water came through the berm, widen that area, be sure it isn't a steep fall, and you will have a natural spillway. Be sure to vegetate the area, or add riprap, if the grade is too steep. Minimize erosion on your spillway.

Bob,

Thanks again for the info. The new spillway is working well. The spillway is about an inch higher than the lowest inlet, so water backs up a few feet into the inlet at full pool, but it's no big deal. I'm happy with how things worked out considering my initial plan was totally flawed.

I have one more question...based on Pond Boss advice, I had planned to compact the pond floor before filling. Unfortunately, the rain beat me to it. The pond is holding water just fine, but will the mushy bottom cause any probs. for the fish nests after I stock in the Spring? I am looking to stock minnows, bluegill, and eventually a few channel catfish.

Fathead minnows stick their eggs on the underneath side of firm objects, like floating wooden pallets, or PVC pipe in shallow water. Bluegill make nests in colonies, in water less than a foot deep. Soft mud is not often a deterrent to bluegills. They find a spot. But, watch and observe. If you aren't seeing baby bluegill mid-spring, look for their colonies. No colonies, then provide spawning habitat.

steve...concerning this time of year/clay and grass. i raised my spillway and dam recently, had bare soil. and as Bob stated also, i wanted to prevent erosion. I think ideally that bermuda is best for erosion control (i'm not a grass expert, just a general comment) however, i can't expect that until summer. my pond filled up last year by jan/feb. sooo, i threw some rye out ("Improved Marshall Rye"...if that means anything) and some winter wheat... we've had some crazy cold and warm days in my area lately. but the winter wheat has come up great. i planted it last year in non clay areas, well, maybe a little bit of clay in it and some unfavorable soil, and that darn stuff stayed green all winter. plus deer love it. so my plans for grass around my property/yard/dam/pond edges will be throw out bermuda seed in spring and "winter/feed" wheat in the fall...this has been MY best combo... keep in mind, bermuda is not cheap..but spreads well. i think i paid about 3 dollars a pound for bermuda. NOW, in the past i paid about 25 dollars for a 50 pound bag of rye...but as i said above, i think the winter wheat came up better and stayed green longer and fed the deer better than rye...and at 4.50/50# bag of "feed wheat" (which is basically bulk winter wheat...so farm supplies get it cheaper and sell it cheaper) or the pre bagged and ordered by farm supplies "winter wheat" at 7.50/60# ... "generic vs. brand name" . So, if you like this idea, ask your farm supplier for "winter wheat", then ask if he has bulked or "feed wheat" ...kinda like Brand name medicines or generic...same thing, but pay for the name. hope this helps. mark

Bob, you said above that bluegills spawn/build nests in areas about 1 foot deep. in another post i saw today you had discussed the bluegill may spawn again if the water temp returns to above 61 degrees (i think it was your post). i was wondering...i got some fat bluegill that look like they should spawn..but the 1 foot deep areas that i saw the nests this summer..no nests. i think the water temp there is less than 61..haven't checked...but will bluegills make nests and spawn down the slopes and at what depth if the water is above 61 ? does this make sense? i guess i'm wondering if they are spawning at the 3 -5 feet deep range because the water temp maybe more favorable. but i got my pond pretty green and can't see that deep. but the gills sure look like they're about to deliver!

until that layer of warmer water cools, what depth will the blue gill go to spawn? (assuming we know that water won't be 61 degrees at say 40 feet unless it is a power plant lake/hot water lake or whatever.)

For any extended period (several days) the warmest water is always on top because when water on top cools to temps below that of overlying water the upper cooler water will sink or be wind mixed into the waters below. This is how fall circulation/overturn progresses.

Bgill usually spawn in the shallow water because it is the warmest. Warmer water hatches the eggs faster. The faster the eggs hatch the better the survival rate.

oh yeah, ya think i'd remember that from chemistry 101..long time ago!!! ha thanks. mark

Steven, I know it's a little late for advice, but for future reference, a water level would have kept your goodies out of the crack.