HANSARD
SITTING CALENDAR
SEARCH
LIVE BROADCAST
Hansard Dynamic Member Index
Legislative Council - Fifty-Third Parliament, Second Session (53-2)
2015-06-02 Daily Xml
Contents
Pdf Xml

Chowilla Flood Plain

The Hon. J.S. LEE (15:27): I seek leave to make a brief explanation before asking the Minister for Water and the River Murray a question about the Chowilla Creek flood plain.

Leave granted.

The Hon. J.S. LEE: The Chowilla flood plain is one of the last remaining parts of the Lower Murray that has retained much of its natural character, and the development of the river in the Murray-Darling Basin over the past 100 years has greatly reduced the frequency, extent and duration of flood events. This has resulted in the Chowilla flood plain experiencing severe ecological decline. According to locals, the salinity levels in the Chowilla flood plain are quite extreme, resulting in severely stressed trees outside the inundated zone. One of the residents mentioned that there are examples of catastrophic decline in the area, which is now affecting surrounding vineyards.

Along with the concerns raised, it was noted that the Department of Environment, Water and Natural Resources used the airborne electromagnetic data, which showed incorrect salinity levels within the flood plain. My questions are:

1. With the airborne electromagnetic data showing increased levels of salinity, can the minister advise how the department will collect data in the current environmental conditions?

2. Has the department provided a briefing to the minister about this issue?

3. If so, when will the department investigate this matter?

The Hon. I.K. HUNTER (Minister for Sustainability, Environment and Conservation, Minister for Water and the River Murray, Minister for Climate Change) (15:29): I thank the honourable member for her most important, if somewhat misplaced, question. It gives me the opportunity once again to talk about the wonderful work we are doing in terms of the Chowilla flood plain—indeed, what we are doing cross the Murray in general.

With regard to Chowilla itself, new water regulating infrastructure has been constructed on the flood plain to enable delivery of environmental water to the site as part of the Living Murray program. The works include an environmental regulator and fishways on Chowilla Creek, smaller regulators on the Chowilla Island Loop wetland and Woolshed Creek, and the upgrade of weirs and construction of fishways on Pipeclay and Slaney creeks.

Construction was completed in mid-2014, and initial testing of the infrastructure was undertaken from September to early December 2014. Testing involved operation of the regulator to raise water levels in the Chowilla anabranch by 2.8 metres and the concurrent raising of Lock 6 by 400 millimetres, resulting in the inundation of approximately 2,300 hectares of flood plain and wetlands.

Observations and monitoring undertaken by the Department of Environment, Water and Natural Resources showed strong positive responses to the testing, particularly from trees, understorey and aquatic vegetation, invertebrates, frogs, and waterbirds. I am also advised that vegetation also responded positively in the inundated areas, particularly in species such as lignum, which is a preferred habitat for a range of frogs and other flood plain species.

Also, increased zooplankton and macro-invertebrate abundance has been found, which are important food sources for other fauna such as birds, frogs and fish. Frogs were recorded breeding during inundation, including the southern bell frog, which is listed as a vulnerable species under the Commonwealth Environment Protection and Biodiversity Conservation Act and the South Australian National Parks and Wildlife Act.

I am further advised that 25 species of waterbirds were recorded on the wetlands, including migratory species. Six species of native fish were recorded during wetland fish surveys, along with three introduced species, including a high proportion of European carp. Monitoring within some wetland sites indicated a strong carp breeding response, which is not very surprising, given the conditions.

Assessments undertaken in developing the Chowilla project identified that increasing carp populations would be at risk. A carp management strategy was subsequently developed to identify appropriate methods for minimising carp responses and maximising benefits for native species. The Chowilla Regulator Operations Plan incorporates recommendations from the fish risk assessment and carp management strategy.

The 2014 testing was designed and managed to ensure that water quality and flows for key native fish habitat were maintained throughout the testing, in line with expert advice from fish biologists. The operation plan acknowledges that carp breeding will occur during operation, of course, as will the fish breeding of other species, but we aim to maximise the benefits for native species.

A review of the testing event is continuing, I am told. An initial workshop was held in March 2015. A further workshop to review the ecological outcomes will be held in May once monitoring data analysis is completed. The outcomes of the review will inform the update of the operations plan, and identify further work required and improvements that can be made for future operations. The review will include assessment of the carp response, of course, resulting ecological impacts, and options for mitigation in the future.

There is, I understand, a concern within the community and amongst scientific fish experts about carp and the need to closely monitor and manage the infrastructure to limit carp breeding responses wherever possible. The honourable member raises other issues that are important. There has been very positive feedback, I am advised, about the range of outcomes of the testing and the opportunities for ongoing improvement in flood plain conditions. Ongoing targeted monitoring programs will be required, however, during future operating events at Chowilla to fill knowledge gaps and support management that favours native species, and deals with the issues the honourable member raised in her question.

PARLIAMENTARY BUSINESS
MEMBERS
GET INVOLVED
ABOUT PARLIAMENT
VISIT
LEGISLATIVE COUNCIL
HOUSE OF ASSEMBLY
CONTACT