ITs hard to guarantee against the stupidity of people
They need a grate, but it must be far enough away that the current is NOT strong enough to suck you against it.
This IS a huge security breach- and there should be a grate
Put a cage on the lagoon side, with some of it above the water, and monitor it for invaders. Anyone comes in gets the same treatment the USAF used to give college students in Grand Forks who got too close to the fence around a missile silo—or worse.