John de Boer of Launceston believes a cutting bypassing Stephensons Bend would improve the Tamar River silt problem. Picture: PHILLIP BIGGSGorge flow a silt solverMariner says narrowing Tamar would scour river
LAUNCESTON mariner John de Boer believes the Tamar silt problem could be solved with a narrower river at Home Reach and a channel through Stephensons Bend.
Mr de Boer, a builder who worked for Hydro Tasmania in the 1960s, said that a faster and smoother flow from the Gorge would help carry sediment downstream and create a cleaner, deeper river.
``Narrowing the river in Home Reach would increase the speed of the tidal flow and help scour the river.''
He said that the idea of a channel at Stephensons Bend wasn't new.
``They started digging a channel through there in 1915 and there were a couple of other attempts over the years.''
The idea then was to make the river more navigable and reduce the need for dredging.
The path of the channel is still visible in aerial photos of the area.
Mr de Boer, who has been boating on the Tamar since moving to Launceston in the late 1960s, is converting the former 20-metre Ulverstone-based pilot boat Girralong into a charter vessel.
He said that the incoming tide eliminated the effect of water from the Trevallyn power station in shifting sediment from Home Reach.
``Diverting some of the water that goes through the Trevallyn dam to a restored Duck Reach power station would also help.''
He said that sheet piling (a continuous metal barrier) from Ritchies Mill to Home Point, on the eastern bank, and from Tamar Marine to the Tailrace, on the western side, could be backfilled with river material to reclaim land for new recreation areas.
``Straightening the river with a channel through Stephensons Bend would get the water away from the city and reduce the flooding risk.''
He said that the channel at Stephensons Bend could include an opening bridge (for boats to travel through) across the river connecting the West Tamar Highway to the Alanvale Connector on the eastern side.
The existing settling ponds in the area could become retention basins and also help mitigate flooding.
Funding for a bridge across the Tamar in the area was part of a Launceston City Council submission to the federal government in March. The cost was put at $50 million.
``I'd just like to see the experts think a bit outside the square on the Tamar's problem,'' he said.