I'm dealing with an issue (probably a common one) on a pond I didn't build. The homeowner says one section of his pond liner gets pushed up when it rains heavily. I can see why. The pond was basically built on top of a massive rock that forms a bowl of sorts. The pond builder has told the homeowner to install a 4" drain from the base of the skimmer to a point in the yard that is below the lowest level of the entire pond. I don't see how this will necessarily help since the bottom of the pond will be a good 12" to 16" below the base of the skimmer (the skimmer is resting on part of the rock). In my mind, the weight of the water would have to push the water collecting under the liner over to the drain at the skimmer base. I'm thinking of suggesting to the homeowner that he drain the pond so that a pipe can be situated under the liner to its lowest point (where the most water would collect) and let the weight of the pond water force the water that is collecting under the liner into the pipe and force it out to a point in the yard where the level is lower than the lowest level in the pond. This won't be easy but I feel it is a better solution than simply putting a pipe at the skimmer. If anyone is still reading this and understands my poor excuse for explaining a situation, I would appreciate some feedback. Thanks!