Maintenance of the GMW channel delivery network is crucial to ensure we provide an efficient and reliable irrigation supply. In Cohuna, the Torrumbarry Number Three Channel (TO 3) is a critical part of the region’s modernised irrigation network and runs from the Cohuna Weir along the Murray Valley Highway toward Koondrook.
TO 3 is primarily operated as an irrigation channel to deliver water for agricultural and domestic use. It is located near the Cohuna foreshore precinct which includes the Visitor Information Centre, shared pathway, visitor parking and outdoor dining areas. The channel banks are lined with native trees, shrubs and introduced species and contributes to the natural and visual amenity of the Cohuna township.
Why are the works needed?
Seepage and bank erosion has been detected along the channel. In addition, aquatic weed matter and a build-up of silt are impacting the efficient flows of water within the irrigation channel.
- GMW’s annual channel maintenance program has identified a section of the TO 3 channel in Cohuna requires remediation.
- The size and density of the vegetation growing in and along the banks of the channel limits access for maintenance.
- Cracks in the channel banks have been unable to be repaired.
- The current condition of the channel and vegetation pose a potential risk to the local community, visitors, and property through the loss of tree limbs and/or potential uprooting.
- The condition of the channel is impacting the efficient delivery of water to downstream irrigation customers.
Valuing Native Vegetation
GMW recognise the prominent location of the channel and the significant contribution the natural environment makes to the visual and recreational amenity of the township. Our regular channel maintenance program has been monitoring the operations and performance of the TO 3 since 2013.
An environmental consultant has conducted a detailed native vegetation, environmental, and ecological land assessment along the length of the channel. Overall, 159 native trees were assessed.
The assessment identified a number of the established trees in and along the banks that pose a significant risk to public safety and property through tree uprooting and limb falls due to instability and introduced species that have penetrated the banks creating leaks and seepage.
Works Methodology
In consultation with the Gannawarra Shire Council, the GMW project team have developed and sought permission for an in-channel rehabilitation program to gain access to the channel, restore capacity and functionality and minimise the impact on the established native vegetation.
A total of 22 native trees and four introduced species (palms and peppercorn trees) have been identified as needing to be removed due to the risks they pose to public safety and the essential operations of the channel.
The following measures will be in place to minimise the impact to native trees bordering the channel:
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- Overhanging branches will require trimming to make safe. This will be completed by qualified arborists.
- The trees in the channel, where possible will have the banks backfilled to protect the root ball and stabilise the tree.
- Only where not possible to fully protect the tree will trees be removed.
Timing
From Wednesday 15th May 2024, GMW will begin dewatering channels in the Gannawarra Shire area as part of our 2024 Winter Works program. The rehabilitation works will take place from the 20th of May and will take approximately eight weeks to complete (weather permitting).
In order to safely conduct the works and maintain public safety there is a need to close all access to the shared pathway.
Local Area Impacts
During this time residents and business may experience the following:
Shared Path Access:
- The walking access track along the east and west sides of the channel and pedestrian bridge adjacent King George Street/Murray Valley Highway will be temporarily closed. An alternative path will be provided and clearly signposted.
- The Cohuna Public Recreation Reserve will remain accessible via the Cohuna Island Road.
Vehicle Access:
- A traffic management plan will be in place for the Murray Valley Highway involving possible short duration single lane closure for the southbound lane during the period of works.
- There will be increased vehicular activity including trucks and machinery along O’Brien’s Road, Rosalind Street, King George Street/Murray Valley Highway and Western Road.
- This may result in an increase in heavy vehicle related noise and vibration.
- GMW has been working with the Gannawarra Shire Council to advise all emergency and essential services of these planned works.
Aquatic weed removal and desilting:
- The build-up of silt and aquatic weed in the channel network impacts the water quality and flow rates of water across our distribution network.
- During the works GMW will be removing the build-up of aquatic weeds and silt. Silt will be dried in the channel reserve area prior to being transported offsite. The organic nature of the silt may result in some minor odour as it dries.
Have a question?
Representatives from the Project Team will be in Cohuna on Monday 6th and Tuesday 7th of May to answer any questions the community might have in regards to the planned works.
Drop in session details:
GMW will be hosting drop-in sessions for people wishing to learn more on the following times and dates:
- Monday 6th May - 12pm-2pm & 4pm-6pm
- Tuesday 7th May - 12pm-2pm & 4pm-6pm
Venue: Cohuna Neighbourhood House - 29 Market St, Cohuna
To assist with scheduling and catering, please register your attendance and preferred time by emailing communications@gmwater.com.au
If you have a question regarding GMW’s winter works program and what it means for your water supply please contact our Customer Service Centre between 8.30am and 4.30pm Monday to Friday on 1800 013 357.