Chowilla Works Update – September 2014
Chowilla is finally open again after 4 years.
The new regulator is complete and all boat traffic can now pass freely.
Slaney Weir has now been open for a couple of weeks.
There is an on-going testing programme that is due to start on the 8th September through to late November 2014.
This won't affect access but conditions experienced upstream of the Chowilla regulator will vary. (Currently pool level at Lock 5 is 100mm above normal operational level and Lock 6 will vary with maximum of approx 400mm above normal pool level.
This variation is to be tested over the coming months and will allow for flooding of the floodplains to benefit birds, fish, frogs and vegetation according to Jarrod Easton from DPTI
Portage conditions past the weirs and regulators haven't been scoped at this stage – please check with DPTI or Murray Darling Basin Commission before you go to get an update, for when the regulator is in action.
I have included below a summary of the testing passed to me by email and website information to help you get a better handle on what is occurring.
I have also include photos of the Chowilla regulator taken from upstream, Pipeclay and Slaney Weirs taken from downstream.
Portage around Pipeclay is as before on the eastern bank. Slaney has steep access/exit on the downstream side while on the upstream side there is now a landing point on the river just to the east of the creek entrance where vehicle access was created during construction. The ground is fairly rough near the weir with a lot of logs laying around.
The portage upstream of Customs House into the Hypurna Creek has had a tidy up and there is safe clear access across right at the 399 mileage marker.
SUMMARY OF PLANNED TESTING
The testing will involve use of the regulator up to a ‘medium level’ operational height to raise water levels in Chowilla Creek and its associated anabranches by approximately 2.8 metres with resulting progressive inundation of low lying wetlands and floodplain areas within the Chowilla Game Reserve.
It is anticipated that water levels will be raised sufficiently to enable water to be passed through structures on the Chowilla Island Loop and through the Woolshed Creek South and East regulators allowing these structures to be tested as well.
Testing will ensure that the structures can be operated as designed. Engineering checks and monitoring will be undertaken throughout the event. The testing event will also provide ecological benefits for the floodplain.
As water levels are raised behind the Chowilla regulator, Lock 6 will also be progressively raised by a maximum of 40 centimetres above its normal operating level to ensure that flow velocities through the Chowilla anabranch can be maintained. This is important to enable the management of water quality and protect critical habitat for native fish including the Murray cod.
If the regulator is operated at flows to South Australia of below 15,000 ML/day there may also be a 10 centimetre raising of Lock 5 to ensure optimum operation of the Chowilla regulator fishway.
It is intended that the testing event will occur over approximately 3 months between early September and early December. Lock 6 weir pool water levels will be raised for approximately eight weeks from late September to mid-November.
The FAQ and factsheet and video can also all be downloaded from the website as follows:
Website: www.environment.sa.gov.au/chowilla-floodplain See ‘related links’