The Angas Bremer Water Management Committee made use of a small volunteer grant from the South Australian Murray-Darling Basin Natural Resources Management Board on 27 September to run a free bus trip to visit two of the securing low flows trial sites in the Angas Catchment. This included a number of information sessions with speakers discussing the new FrogSpotter app to monitor South Australian frogs, an update on the latest activity in pest and weed management in the Langhorne Creek area and information on the progress and content of the revised River Murray Water Allocation Plan.
Two low flow trial sites were visited which showed a couple of different options to return low flows. The first was a traditional ‘bypass’ device that diverted water prior to entering a 40 ML dam. The second site used a device that won the Low Flows Design Competition run by Natural Resources SA Murray-Darling Basin. The competition asked farmers, inventors, engineers and designers to propose new ways to secure low flows from dams and watercourse diversions in the Mount Lofty Ranges. One of the winning categories was the design used at the second site which is a ‘release’ device. This device has a sensor that detects flow into the dam and calculates the necessary volume of water that should be released. This volume is then released over the dam wall via a siphon pipe.
The pros and cons of each device were discussed. This included, for the bypass device the simplicity of the design, construction and maintenance but potential for large amounts of trenching and pipe to get the required 2 degrees of fall from the diversion point to downstream of the dam. The release device has a very small footprint, able to be set up relatively quickly and easily on the dam wall. However, it contains electronics that in most cases will require technical expertise to fix if any damage or faults occur.
The day was a great opportunity to learn more about activity happening in the Langhorne Creek area and beyond.
Site 1 – a low flow bypass device
Site 2 – a low flow release device