Tamar River/kanamaluka is not actually a river. Rather it is a tidal estuary covering 68 kilometres and entering Bass Strait at Low Head.
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On one day there are protests and "fix the mud" signs decrying the accumulation, coupled with a teenager being rescued from the Head of the River after becoming stuck, while the next there is frivolity at the Cataract Gorge as swimmers take to the Basin, a dolphin (albeit sick) is swimming in the North Esk River, and there is a picturesque full tide on sunset.
Learn to "love the mud" is an answer if the estuary was not the economic lifeblood of the city.
For amenity and to support development, businesses, and recreation providers who we have encouraged to invest, the state and federal governments must reinstate a dredging program as a community service.
Frankly, learn to love the mud is akin to saying learn to love the cold should the City of Launceston council decide to stop heating the regional aquatic centre because it is too expensive.
The banks of the Tamar Yacht Basin at Home Point, the meeting of the North and South Esk, is the most contentious confluence of the river where activities such as hospitality, sport and recreation, tourism, industry, and boat mooring are established.
IN OTHER NEWS:
The Tamar River/kanamaluka is also a conservation area managed by the Tasmania Parks and Wildlife Service, therefore requiring a permit to undertake any mitigation works. This requirement is completely appropriate.
To explain the challenges that we continue to face in simple terms: the estuary, like a blocked toilet, cannot fully flush.
By comparison, the Derwent River/timtumili minanya stretching from Lake St Clair to Storm Bay is 239 kilometres long and deep.
It incorporates a five-and-a-half wide kilometre estuary, home to our state's capital city, Hobart, before emptying into the Tasman Sea.
Hobart is just 19 kilometres from the river mouth and on an outgoing tide flushes the Derwent River.
As a result, it is often a gentle reminder in jest that in 1798 during colonisation Bass and Flinders should have established the base at George Town when they moored.
Our river is further complicated by the fact that the silt as it is commonly known is acid sulphate soil. In situ, or when not exposed to air, the silt presents no risks.
However, when exposed to oxygen, the iron sulfides react and create sulphuric acid, which can kill marine life up and down the estuary.
Confused?
Basically, when the tide goes out the silt sticks to the salt (flocculation) and travels down the river, but most of it never reaches Low Head nor out to sea. Rather, it simply returns on the incoming tide.
Further, obstructions in the tributaries and down the river including log jams, willows, jetties, groins, dikes, marinas, and rice grass, with many designed or planted to assist with the silt over the years exacerbates the problem.
And further still, the Trevallyn Dam and power station, agriculture and forestry, and an utterly inadequate combined storm water and sewerage system supporting a modern and rapidly developing city delivers one of the most talked about and theorised estuary systems in the world.
Conclusion: silt is difficult to manage and when exposed to oxygen without treatment, it is bad news. And unless you have an endless supply of lime to treat the soil, it is problematic to make use of the extracted resource as landfill.
So, day upon day, year upon year, there are yarns and calls for funding and scientific research regarding our city's major waterway.
Complaints and solutions in equal measure reach fever pitch around election time, particularly for candidates in the federal and state seats of Bass where the river has been a talking point for generations.
Plant more rice grass, dredge it, rake it, let more water flow, build a lake, or dam and flood it has all been mooted or tried.
Fortunately, the Tamar Island Wetlands Reserve has been spared from development. Wetlands are the "kidneys of the sea" - they clean the river of its contaminants.
However, it is now easier to see tiger snakes than the settling ponds at the Tailrace with the native grasses and bullrushes reaching gigantic proportions.
The ponds are used to house the silt when dredging is considered the most appropriate solution.
But dredging is mighty expensive and state and local governments claim they do not always have the money to spare, so we make the best of what we have - on high tide we show it off while at low tide we head anywhere but the river.
The best solution, as always, is natural - in an unnatural environment.
When the tributaries flood and the water cascades over Trevallyn Dam, a scourer is set free going to work scrubbing the bottom of the basin and delivering the volume of water required to flush Tamar River/kanamaluka the complaints subside like the flood waters.
Alas a 2016 flood occurs once every 50 years and was mighty concerning for Invermay and surrounding floodplains and suburbs.
We should learn to understand the mud, but it will never be love.
- Brian Wightman is a former Tasmanian Attorney-General and school principal.
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