Water keeps getting behind pond liner

[addy1]

Sounds very much like a "French drain." You can also find info on how to build them using perforated corrugated pipe.

yep modified to work the way I needed.

 

[Waterbug]

French drains work great in soil that percolates well and where ground slopes.

In soil that doesn't drain well, or flat ground, like when liners are floating a French drain won't work. The water needs some place to go.