Thanks for the suggestions. The track hoe was here over the last 2 days, and so I had to fill the trench with the dry hydrant and did not have time to put in a collar. All this pond work has been going on in the middle of my elk hunting season!Anyway, I did pack under and on the sides of the pipe with the shovel handle and then the contractor put guys to work with a jumping jack to compact the clay on top. I'm thinking of adding the pond liner collar on the surface and then hand compacting it with more clay.
Of course if I get an elk in the next day or two, then I'll probably blow off the collar project and put bentonite around it if it leaks next spring!
But the exciting news is that my excavate/build sedimenation galleries upstream/and line my leaky pond with clay and put in the dry hydrant project is finished! Now I'm filling it with water from the solar pump on the well which will take awhile, giving me time now to place the pea gravel, build more structure and start the recovery work from the surrounding track hoe damage. I'm going to have a fun winter working at the pond.
Thanks to everyone on this website-your advice has been very helpful. When I get a chance I'll post pictures. Barbara