31 Jan 2011
It was not that long ago that the department was pulling out all stops to warn boaties about the hazards of low flows into the River Murray, such as snags, sandbanks and weed infestations.
It certainly adds to the cliché of Australia as a land of droughts and flooding rains that we are now dealing with not a scarcity of water, but a massive excess of it coming down the river.
Given the system of weirs and locks that manage the amount of water travelling down the river, it is an indication of the sheer volume that is coming that there will be flooding and considerable force of flow – particularly at the Murray Mouth.
So we now face new dangers on the river that users must be aware of the keep safe.
The power of the flows in the river have increased considerably, to the extent, in conjunction with the effect of tides, that people in canoes and low powered vessels should avoid being in a situation where they are trying to go against the flow to stay safe. For example, there is greater potential around the Murray Mouth for vessels and people to be washed out to sea, so take great care in any of these waters. The area is also quite turbulent, so boats can capsize and endanger all involved.
Stay away from barrages near the Murray Mouth
The flows on either side of barrages have considerable force, while not all that fast they are powerful. Upstream vessels will be dragged towards the barrage and downstream rapidly pushed away – posing a threat to safety. It is advised that unpowered vessels like canoes and kayaks, sailboats and boards and low powered vessels stay more than the recommended 150 metre distance from the barrage.
Debris in the river
During the drought eucalypt saplings re-established in many backwaters. There is potential for these saplings to dislodge and end up in the main stream causing problems for vessels.
Furthermore, a number of larger trees that fell near the water during the drought have dried out sufficiently so that now they are likely to float off into the river.
Other debris, mostly small limbs - 200 mm to 250 mm - dropped by the trees through the drought, are now floating into the main stream with the flooding waters and creating a hazard.
With the level of the river very high, passing boats that create wash have the potential to erode sections of river banks, undermining the lawned areas. The wash from larger vessels also has the potential to lift boats moored along the side of the river with potential damage to vessels and the banks. So, take care when travelling up and down the river so as not to contribute to further damage.
Wash may also exacerbate a threat to infrastructure and homes located on the rivers banks, particularly where they have been inundated with the high water levels.
Given these new dangers to all river users, due to the high flows, I ask that great care is taken on the newly refreshed River Murray over the coming months.