After several years metal principle spillway or draw down pipes installed in pond dams rust or corrode to the point they begin to leak or collapse. Maybe the pond you have never had a draw down pipe. In any case, the new pipe must be installed in a proper manner so it will not fail. In more cases the preferred material is PVC plastic pipe. Consult with your local Natural Resoucres Conservation Service office or a private engineer to determine proper size and other specific needs in your project.

Below are some key elements that are essential to a successful pipe replacement. It is not necessary to drain the pond to do a pipe replacement.

Please also view Basic Elements Of A Pond to gain a better understanding of pond dams before being project. Recommend printing page for reference.

[Correct Method]
[Incorrect Method]

Step Ref. No.
1REMOVE OVERBURDEN in at least a 10 foot wide trench down to the old pipe. In addition, a side slope of at least 1.5:1 must be maintained on either side of the trench so soil can later be repacked properly. DO NOT dig a vertical trench to dig out the old pipe or to install a pipe in a pond without a pipe. It will wash out.
2REMOVE OLD PIPE AND COLLARS must be completely removed. DO NOT just attempt to fill the old pipe with concrete. Sometimes a drop inlet style pipe can replaced with a canopy inlet design. Consult with your engineer about the possibility.
3RECONSTRUCT PAD along trench to match the planned pipe grade.
4ANTI-SEEP COLLAR locations are determined. Soil is excavated to accommodate collars.
5NEW PIPE is placed in the trench, anti-seep collars attached and pipe is assembled.
6SOIL IS MANUALLY TAMPED around and along the full length of the pipe to at least 2 foot of depth over pipe. Also, hand tamp around the anti-seep collars.
7ANTI-SEEP COLLAR Prevents water from seeping down the outside of the pipe which could wash out the pipe.
8FILL remainder of the area in 6 inch lifts and compact until the pond dam is fully restored in size.
9SEED dam as soon as possible, preferably before the first rain. Mulch if possible.

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