Seventeen years ago, when the Bridge Marina was built it should have had a rock wall, like all good marinas do. Another design error was to not put the entrance and exit at the northern end of the marina, instead of into the harbour like a huge scoop. An opening on the southern end would facilitate total flushing.
Tauranga Bridge Marina, although privately-owned, is a major asset to Tauranga and a major employer of locals, servicing up to 500 vessels annually.
A marina's purpose is to provide safe and comfortable berthage for vessels. Bridge Marina falls short in several ways. Should an excessive tide roar up the harbour the whole complex would collapse, (remember Lyttleton Marina).
The existing entrance has two major problems - When vessels head toward one another at 90 degrees with and a 3 knot tide, neither can stop, one with the tide behind and the other with tide-side on? Secondly it scoops in any debris that is bulldozed into the upper reaches of the harbour, which putrefies and is a health hazard.
The marina is a permanent structure, therefore needs to be protected by a permanent wall.
As for the tidal restriction, the Marina is in the eddie down stream from the Harbour Bridge. Also rock walls are a great place for fishing.

Dudley Hessell, Te Puke.