getting water over pond dams without erosion

Discussion in 'Homesteading Questions' started by Paul Wheaton, Oct 23, 2004.

  1. Paul Wheaton

    Paul Wheaton Well-Known Member

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    I have 80 acres and two ponds. Next year I plan on expanding/reworking these two ponds, plus adding another dozen ponds.

    The two existing dams use culverts to carry the water across the dam. On both dams, the culverts have lots of problems.

    On the upper pond, the culvert is high and frost heaves in the winter move it. Two winters ago the culvert was heaved so that the intake was higher than the dam and water ran over the top of the dam. Plus water finds its way around the culvert and is starting to erode the dam.

    On the lower pond, water is finding its way around the culvert and is starting to erode the dam.

    In the summer, the amount of water flow here is very small. So small, that the water tends to go underground in many places. The water running into the upper pond is pretty good. The runoff from that pond eventually ends up at the lower pond where the water running into that pond is zero. Without fresh water, the water becomes warm and oxygen becomes too low, making aquaculture projects difficult if not impossible. I'm thinking that the solution is to make series of ponds with the runoff from any pond running into something water tight and carrying the water to the next pond. Either a poly pipe (which wouldn't be enough for the spring flow, but enough for summer) or a series of cement/tufa catch basins/troughs.

    Each of these ideas has problems, not to mention expense.

    Any suggestions?
     
  2. caballoviejo

    caballoviejo Well-Known Member

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    Paul, how big are your ponds and how deep is your frost heave?

    Re water getting around the culverts, put collars around them to stop laminar flow between the culvert and soil.

    Do you have clay soil?
     

  3. Paul Wheaton

    Paul Wheaton Well-Known Member

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    The two ponds I have now are a quarter of an acre apiece.

    Legal frost line is 18 inches, although many people have trouble with that, and those people are going with three feet. Plus, with a culvert, won't it need to be buried deeper because it lets cold air in? And the ends of the culvert are sticking out in the cold ...

    We have mostly gravely soil (decomposed granite), but we do have some clay spots.
     
  4. Chuck

    Chuck Well-Known Member Supporter

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    The proper way to install the pipe is an L-shaped pipe going through the bottom of the dam (preferably with a concrete collar around it) and the vertical piece coming up to the desired waterline about 6 -10 feet in from the dam. that way water doesn't go over it.

    The other way is to make a concrete spillway (I've heard riprap will also work) for the water, but then you won't be able to walk around the pond without making a bridge of some sort.
     
  5. Paul Wheaton

    Paul Wheaton Well-Known Member

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    Chuck,

    I'm wrapping my head around the idea of the L shape. My lower pond is that way now.

    I guess that the benefit is that a majority of the culvert is below the frost line. But if you put it at the bottom of the dam, won't it need to be much longer than if it was about four feet from the top?
     
  6. caballoviejo

    caballoviejo Well-Known Member

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    Reasons for puttting the drain pipe below the dam: 1. as the water rises head pressure increases and water is discharged faster. Especially good in a flood, the is no head if the pipe entry is close to the top of the dam, 2. discharge is closer to or at the natural grade of the land - not higher up on the dam where it where the likelihood of erosion problems increase, 3. the vertical portion of the pipe can be a stand pipe, i.e., it can be fitted into the elbow near the bottom of the pond without glueing. This allows it to be removed if draining the pond is desired, allows substitution with other lengths of pipe height.

    Instead of being open at the top the vertical pipe can be turned down with a 180 degree curve (as in a sink's or toilet's p-trap) to keep it from getting clogged by floating debri (or beaver work).

    The easiest, cheapest solution to excess water is construction of a broad earthen spillway towards an upslope side of the pond. This depend on the lay of the land, of course. The objective is to release overflow over a broad area and with slow velocity so that erosion does'nt occur.

    Two inch pvc as standpipe drain through the dam can be used to "tap" usefull water from the pond.
     
  7. agmantoo

    agmantoo agmantoo Supporter

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    Paul, read the info here http://www.ponddampiping.com/syphon1.html on the syphon method for water control. I use this of 2 ponds, both under 3 acres and it works fine. I do suggest that a collar be used however. This is particularly good for removing stale, low oxygen water. All ponds should have both an overflow and a spillway IMO.
     
  8. Paul Wheaton

    Paul Wheaton Well-Known Member

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    caballoviejo,

    Some excellent info! It loads my head with all sorts of excellent ideas. The point of keeping the water flow off of the dam is quite important. And the high flow keeping debris out is another point I had not thought of.

    The p-trap idea is excellent!

    agmantoo,

    Most of that page is over my head. I've read it three times, and I plan to keep reading it until I get it. But if nothing else, it makes some great points. I like the idea of pulling water from nearer the bottom of the pond. That water will have less oxygen. And as it makes its way to the next pond, it will pick up more oxygen. Plus, in the winter, it will be warmer and less likely to freeze and cause problems.

    Excellent! My brain is unstuck! Thanks guys!!!
     
  9. texican

    texican Well-Known Member

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    I use a wide earthen spillway (off to the side of the dam, on undisturbed ground) on my 8 acre pond dam...having water go over the 35' dam would quickly erode it into a catastrophic failure...so I try and keep old tarps around, so if we get one of those 6"+ rains, and it threatens to go over the top, I can place the tarps in the lowest spots, mitigating most of the erosion off the high portions of the dam.