Pond Boss Forums POND CONSTRUCTION Renovating a Pond or Lake? 1/2 Acre Pond Leaking

If it was me, I'd remove the island. The pond could be much deeper without it without having sides that were too steep. Liners really, really should be covered with 12+" inches of clean dirt to protect the liner from UV. exposure.

I like the clay, but if it's not available in your area then a liner is the way to go. BT Liner has the lightest, toughest liner that I have seen. AquaArmor Liner

They have a tutorial on how a liner should be installed in a pond too.