Pond Boss Forums POND CONSTRUCTION Building a dam Do I need a collar on a dry hydrant?

My best guess is to place it where it can be sealed the best. This might depend on variations in the dam material, or a location in the trench where it will be easier to work, or ???

It would certainly be possible to make a collar yourself. We purchased 4 anti-seep collar kits from a nearby drainage supply house; these consisted of a 4'x4' sheet of heavy, flexible rubber and 1"x2" fir strips to make a square framework. You cut a hole of appropriate size through the middle of the rubber and slide it onto the line in the dam either before or after stapling it to the square frame. The wood will of course rot in a couple of years, but it's job is to hold the rubber sheet in place while you pack clay as hard as possible on both sides of the sheet all around the pipe.

I messed up cutting the hole in one sheet, got a slice extending farther than the pipe diameter, and got creative in an attempt to fix it (and help fasten the torn sheet to the pipe) with rubber inner tubes, silicon seal, and cable ties. This held together fine while we backfilled and tamped; I don't know what it looks like now but the dam holds water.

I cannot guess as to the suitability of pond liner for this purpose (no experience with it), but 19 years of fixing (and all too frequently re-fixing) washed-out holes at cracks in field drainage tile has showed me that rigid, plastic-like materials (such as visquilene) are easily torn under ground by moving water. The thicker and the more pliable a material is, the better it should work for this purpose (old inner tubes are my favorite material for sealing tile repairs; I have not had to replace a fix made using them yet).