We are planning to upgrade the Jack Roper Reserve (CSL) retarding basin in Glenroy to ensure it continues to reduce flood risk for the community.
These works will begin in April 2018, weather permitting.
This retarding basin plays a crucial role in managing stormwater in your local area.
Timing of works
Work will be undertaken from 7am to 6pm Monday to Friday and 7am to 1pm Saturday, if required.
What is happening
Aqua Metro Services is delivering these works on behalf of Melbourne Water.
Work will be undertaken primarily on the embankment and in the road reserve on the downstream side of the retarding basin.
The upgrade involves:
- excavating a trench along the embankment and backfilling the trench with a new sand filter
- upgrading the spillway
- removal trees and vegetation along the embankment
- revegetation after construction work, this is a standard practice on all Melbourne Water retarding basin upgrade projects that require tree removal
Once construction is complete, the grassed areas will be reinstated with topsoil and hydroseed. Hydroseed is a mixture of seed, water and mulch that produces grass growth at a much faster pace than regular seeding.
Melbourne Water is working with Moreland City Council and VicRoads to develop a reinstatement plan for the shared path and planting trees elsewhere.
Jack Roper Reserve (CSL) Retarding Basin was originally constructed in 1964. Recent assessments have shown the embankment and outlet filters need to be upgraded to ensure the continued integrity and stability of the retarding basin.
Location and access
This retarding basin is located on the southern end of Jack Roper Reserve, on the south side of the Western Ring Road (M80) in Glenroy. The basin is known as the CSL retarding basin.
Construction crews and traffic will access the site via Morely Street, Glenroy. The work area will be contained to the embankment, spillway and will extend to Merlynston Creek. The work area will be fenced off during construction.
The shared user path, known as the M80 bikeway, sits directly on top of the embankment and will be closed during construction. This shared path will reopen upon completion of the project.
A new path will be established prior to construction and this will be clearly marked as the detour route for all users of the M80 bikeway during construction.
We’ll continue to work with local residents and other users of the basin to inform them of the works schedule and any associated impacts that may take place.
What to expect
As this project is taking place in a residential area, we anticipate our neighbours may notice:
- permanent detour pathway will be constructed, this will be the first stage of the construction, prior to the M80 shared path closure and basin upgrade work
- closure of the M80 shared path during construction, a majority of the works will be occurring here
- large trucks and machinery working in the basin
- tree and vegetation removal from the work area
- site shed and worker amenities installed in the basin
- an increase in traffic in the area, particularly along Morely Street, Glenroy
- some noise, dust and vibration from construction activities, mitigation measures will be in place
Working with the community
We’re committed to reducing impact of construction works on the local community.
We will be speaking with local residents in late 2017 and early 2018 about the upcoming works.
We’ll continue to keep you updated as the project progresses.
Why the project is happening
Melbourne Water has been directed by the Minister for Water to ensure all of retarding basins comply with the Australian National Committee on Large Dams (ANCOLD) guidelines. The ANCOLD guidelines represent the best Australian and international engineering practice in the safe design, management and operation of dams. Each retarding basin is assessed individually so each will have different upgrade requirements to ensure they are compliant with the ANCOLD guidelines and continue to operate safely.
Jack Roper Reserve (CSL) retarding basin has recently been assessed against the ANCOLD guidelines. The assessment has shown that upgrade works are necessary to ensure the retarding basin continues to reduce flood risk and to ensure the risk is as low as reasonable practicable.
Under the ANCOLD guidelines trees must be removed from the whole length of a retarding basin embankment to ensure its integrity and provide the best possible level of dam safety. In the past, it was common practice to have trees on retarding basin embankments. However, as understanding of dam engineering has improved, it has become evident that trees significantly weaken embankments and increase the risk of failure in a high rainfall event. Jack Roper Reserve (CSL) retarding basin will require approximately 26 trees and/or vegetation to be removed as part of this safety upgrade project.
During a large rain event, trees on the embankment increase the chances of embankment failure. They do this by increasing the risk of:
- soil erosion and displacement – when a tree dies its roots decompose and offer open water passages through the embankment
- trees uprooting and taking part of the embankment with them
- water speeding up around tree trunks and causing accelerated embankment erosion
We understand the emotional and environmental importance of trees to the local community and are committed to working closely with Moreland City Council to develop an appropriate plan for reinstatement of trees elsewhere.
Melbourne Water is working with Moreland City Council and VicRoads regarding this safety upgrade to the retarding basin.
We will work with Council to develop a new shared path during construction.
We will develop a reinstatement plan with Moreland City Council for planting of new trees in another location.
Upon completion of works, we will also develop a reinstatement plan with VicRoads for a new M80 shared path on top of the embankment and installation of a new noise barrier.
Melbourne Water is committed to providing regular updates on the project to keep the community informed.
If you do have any questions or feedback, please get in touch: