Big spit: A build-up of sand on Ocean Grove Spit, looking back toward work on the bridge replacement project. Picture: Tommy Ritchie 53080
Andrew Mathieson
Ocean Grove spit appears to be growing from the controversial addition of a second bridge at Barwon Heads, according to Geelong Environment Council.
President Joan Lindros said authorities might have to dredge the spit if it “gets any bigger”.
Ms Lindros said she believed the bridges had decreased water flow near the Barwon River mouth, allowing a build up of sand on the spit.
Objectors to the State Governments Barwon Heads Bridge project initially feared the opposite impact, claiming replacement with two bridges would draw sand away to erode the spit.
The Government has built a bridge for cyclists and pedestrians and begun work replacing the adjacent existing bridge for vehicles.
Ms Lindros said the initial fears of erosion had “obviously not been the case”.
“Changes to any marine area can often have other effects but we never really know what they will be,” she said.
“It’s possible the new pylons have acted like a groyne wall and slowed the flow of the estuary, allowing the sand to build up on the spit and making it a lot bigger.”
Ms Lindros said authorities would have to monitor the spit to determine whether it needed dredging.
“If enough sand was deposited and the spit stretched further out still the estuary would need to be dredged.”
VicRoads regional director for south-west Victoria Robin Miles said an independent environmental study ruled the bridges had “not damaged the spit in any way”.
“The position of the shoreline on the Ocean Grove spit is governed by parameters other than sea level, in particular the dominant wave direction and supply of sediment from the west,” Ms Miles said.
“It is very unlikely that these will change in a manner that would lead to a negative change in the average position of the shoreline on the spit.”
Barwon Coast Committee of Management general manager Bob Jordan was unconcerned about the spit’s growth.
He did not believe the new bridge had affected water flow.
“This is a normal pattern of sand coming and going as it does over the years. We don’t think it’s related to the bridge,” Mr Jordan said.
“It’s just an example of how the sand moves back and forth across the coast and it could go back again.”
