Need Help

We bought a 165 gal pond from Lowe's to upgrade from our 90 gallon pond. I
didn't realize at the time we have a "drainage lip" on one side that goes
down about two inches. This feature will not allow us to fill our pond
close to the rim. What Id like to do is somehow put some liner or another
material over it and caulk/glue it so that I might fill the pond higher.

Any suggestions on how to go about doing this ???????

Thanks