From the Newsroom

Dredging operations can be seen at various times along NSW and Queensland coastal waterways (see picture) and according to one Yamba resident, used to be a common sight on the Clarence River during the 1960’s.

Dredging to alleviate flooding and stop trucks

Rodney Stevens

 

A Lower Clarence resident who witnessed the Clarence River being dredged in the 1960s for the development of Yamba’s Crystal Waters area claims the river is in dire need of dredging which he says will also alleviate flooding and stop fill laden trucks coming into Yamba.

The man, aged in his 70s said the health of the Clarence River is suffering and dredging the Clarence Bar, and areas around Yamba, would be a win-win situation to help improve the health of the river, reduce the impact of floods, and provide fill for development sites.

“Our Clarence River is starving at the moment, it’s clogged up at the mouth and it drastically needs dredging at the mouth, around Oyster Channel, Romiaka Channel, Shallow Bay, and the marina area,” he said.

“If we do get a flood there will be a problem, because the water can’t get away, and that’s what happened in the 2021-2022 flood.”

As history has previously proven, the man said the answer was to dredge the river.

“In the 1960’s we had five dredges working, cleaning up our beautiful river,” he said.

He said an agreement could be reached with the traditional owners of the area around the Clarence River mouth, the Birrigan Gargle Local Aboriginal Land Council about dredging the bar, and the material from there and other areas could be used for filling development sites, preventing numerous truck movements in and out of Yamba carrying fill.

“The developers don’t want to truck the fill in, but they have to, because there is a giant need for housing in the Clarence Valley,” he said.

“By dredging, you are fixing up the mighty Clarence River so that it gets increased water flow in flood times and also alleviating the pressure on parts of Yamba that flood, and the developers can use the dredge material as they have in the past, to prevent trucking tonnes of fill into Yamba.”

The only negative aspect of dredging, the man said, was the impact on the riverbed and sea grasses, which he said take about 12 months to recover.

The man asked what the thoughts of the Yamba Community Action Network Yamba CAN Inc. were on the idea of dredging the Clarence River and using the dredge material as fill for developments.

Challenges of dredging the Clarence River

An engineer and scientist with more than half a century of experience says dredging the Clarence River to alleviate flooding and using the dredged material to fill development sites poses problems and would be challenging.

Peter Maslen is an engineer and ecological scientist with more than fifty years environmental, water, planning and management experience, and is Vice President of Valley Watch Inc and a Yamba CAN Inc member.

Mr Maslen continues to contribute in his retirement to the Clarence Valley through his involvement with local environmental groups.

He said coastal rivers over the last 60 years have silted up for two main reasons, namely, poor land use practices and clearing of vegetation especially waterway riparian zones.

“Dredging coastal rivers has various advantages and problems,” he said.

“The use of dredged fill has multiple problems.

“Dredging of a river bar will improve navigation safety but is a process requiring regular maintenance something that governments are increasingly reluctant to undertake.

“The use of material won from bar dredging for fill has numerous issues including the transport to fill site.

“Dredge material has numerous problems for fill, including the quality of fill and its constituents, time for settlement to obtain acceptable compaction and logistics of supplying fill to a site.”

Compounding the problems associated with dredging, Mr Maslen said were the environmental impacts that would result.

“The environmental impacts of dredging are numerous, including change in waterway profiles effecting both marine creatures and their predators, marine flora which commonly takes a significant period to recover,” he said.

“Evidence of the existing loss of sea grasses in the lower Clarence suggests that recovery would be extremely long, further impacting on the biota including prawns.

“The control of turbidity especially in tidal areas, is difficult.

“In a site such as the Clarence River with the velocities in the main channels, would be a challenge.”