MURRAY RIVER, RIVERBANK SLUMPING

Mr PEDERICK (Hammond) (14:52): My question is to the Minister for Water Security. What action does the government propose to take to prevent a recurrence of the riverbank slumping, which has recently occurred in the Murray Bridge area at Tailem Bend? Slumpings along the lower reaches of the Murray River have been reported for the past two years. It was apparent that falling river levels were the primary contributor to this risk, yet, as we understand it, no specific preventative or corrective actions have been taken by the government, and it is only recently that the report has been presented.

The Hon. K.A. MAYWALD (Chaffey—Minister for the River Murray, Minister for Water Security) (14:53): This is a really important question, because the issue of riverbank slumping is of great concern to the state government and to the communities that are affected by it. The Department of Water, Land and Biodiversity Conservation (DWLBC) has received about 40 reports in relation to riverbank collapses since February 2009, some which noted extensive cracking with the high likelihood of future slumping. A main road is also at risk near Young Husband due to cracking.

The most severe incident to date was on 4 February at Long Island Marina, an 80 metre strip of land. A number of trees and three cars disappeared into the river. Since then there has been secondary slumping extending this total to around 400 metres. Nearby, an SA Water sewer main has been rerouted. We have been unable to locate two of the vehicles that disappeared into the lake bed, and it is indicative of what we understand is the base of the river there. It is very fine silt and, as the riverbank slumped, the cars disappeared into that like quicksand and we have not been able to locate them.

However, DWLBC is coordinating efforts to manage these incidents. Ongoing actions, including fencing off incident sites, removing navigation hazards, establishing a 24-hour hotline for public reporting and monitoring identified high risk sites below Lock 1 is occurring. We have put in place a communications strategy, which has incorporated media releases, newspaper advertisements and distribution of pamphlets; and we have contacted owners in high risk areas individually and had many public awareness presentations.

Factors such as steep riverbanks and the presence of deep water have been used to identify 26 locations below Lock 1 facing high risk of collapse, and relevant landholders and local councils have been notified. Council has been pushing some parts of the bank to reduce the slope level and the like in areas where there is high risk.

The overall management approach covers legal compliance, scientific and technical advice, local knowledge and other responses. All relevant agencies, including local councils, SA Water, Department for Transport, Energy and Infrastructure and ETSA are participating in this process. A technical expert has been engaged to provide advice and is consulted on a needs basis.

One of the important things to note in this entire process is that we are all working together to try to minimise the risk to public health and public safety in relation to these incidents. We are playing a very strong role in ensuring the community is well informed and landowners understand what their responsibilities are, and we are working to minimise the risk on land that the government is responsible for managing. It is not easy.

The member suggests that remedial action should take place. It is very difficult to undertake remedial action in this instance. It is a natural phenomenon as a consequence of the low levels in the river, and we are doing all we can to ensure that the public is protected from the risk of these riverbank slumpings.