Thought-Factory.net Philosophical Conversations Public Opinion philosophy.com Junk for code
parliament house.gif
RECENT ENTRIES
SEARCH
ARCHIVES
Commentary
Media
Think Tanks
Oz Blogs
Economic Blogs
Foreign Policy Blogs
International Blogs
Media Blogs
South Australian Weblogs
Economic Resources
Environment Links
Political Resources
Cartoons
South Australian Links
Other
www.thought-factory.net
"...public opinion deserves to be respected as well as despised" G.W.F. Hegel, 'Philosophy of Right'

Tasmania: river problems in Launceston « Previous | |Next »
February 6, 2010

As I'm off to Tasmania for a holiday next week with Suzanne. It's a break from work for Suzanne and a photographic roadtrip for me.

ratrace.jpg

So I'm interested in what is happening in that island state, environmentally speaking. One issue is the Tamar River silt problem, which refers to the massive amounts of sediment flowing into upper Tamar Basin near Launceston. Close to 30,000 cubic metres of silt is deposited each year. Boats now sitting in the mud at what was once a very picturesque part of the city's riverscape.

One consequence is that the increased amount of mud in the Basin effectively limits the space for the rising river waters---a one in 50-year flood event would lead to significant property damage and an emergency evacuation response in the low-lying suburbs of Launceston. The solution has been dredging and building flood levee banks around the city.

One cause of the increase silt is the diverted water flow down the Cataract Gorge that now passes through the Trevallyn Power Station. This has reduced the natural flows down the Gorge of 20-50 cubic metres per second has been reduced to 1.5 cubic metres per second. There is not enough water entering the basin to flush the silt away.

The increased sediment that is choking the Tamar to death with silt can be traced to the North Esk River and the North Esk catchment, rather than the tides bringing silt up the estuary Its bad catchment management. There needs to be a vegetation buffer zones (up to 100m wide) tree planting, cattle control and better regulation of agricultural and forestry practices.v

| Posted by Gary Sauer-Thompson at 4:32 PM | | Comments (2)
Comments

Comments

Some of the low lying suburbs are actually (pretty much) reclaimed swamp. King tides will bubble up into gutters regardless of the silt and river flow into the estuary. In the face of sea levels rising these suburbs ought to be abandoned, even though recently a councilor wanted some pork barrel from John Howard to waste money on barriers. If it had happened then the semi-industrial and low rent situation would have changed and been more safely gentrified.

Meika,
there seems to be a problem amongst the city fathers in Launceston in accepting that the silt buildup in the upper Tamar is caused by bad catchment management practices.

This denial wouldn't have anything to do with forestry would it?