Jeff,
If the ocean is overtopping a berm, hydraulic modeling of a pond is probably moot. It is likely that models of coastal flooding ignore depressions such as ponds (they will be filled). Is there a flood study for this area?
you might try the Eurotop manual, there is some online software that can calculate overtopping rate due to wave runup on berms and seawalls. you will need wave period and design height which come from a wave study. alternatively, find the shore protection manual and brush up on your calculus