At the last boot-camp during the discussion on repairing water and sewer lines that were failing it occurred to me I had used this epoxy coating system on a rental building I own.
http://www.curaflo.com/EpoxyPipeLining/EngineeredFlowLiningSystem.aspx
This is not the company I used, but it is spot on as to how the process works. They shut off the water to the entire system, dry it out with compressed air, clean out the corrosive material in the pipes, blow this epoxy through the lines that coats the lines. It was much less expensive to fix my pipes this way in my small apartment building, and I am pretty sure this would save large amounts of money on replacing water lines in a park, especially if the lines are really hard to get to.
anyway… just a taste of what is shared at a boot-camp…