It would also provide 20 hectares of new saltmarsh wetlands for birds and fish to breed and feed in.
The Ford Rd boat ramp provided boating access to the Kaituna River and the river-mouth at Te Tumu Cut.
A new public jetty and sealed carpark had also been provided.
There were a few changes that people would have to get used too, including boaties needing to travel upstream for 1km to access the main river channel before heading out to sea via Te Tumu Cut.
"There is a strong downstream current to watch for, especially when the new diversion control gates under Ford Rd are open on the rising tide."
Warning lights would flash or sirens will sound just before the gates open and close, but people should avoid jumping off the bridge or swimming near the boat ramp or control gates at any time.