Long Island Retarding Basin Upgrade (Frankston)

Shape Copy 2 Completed

John Holland-KBR Joint Venture (JH-KBR JV) delivered upgrade works to the Long Island Retarding Basin at Frankston, on behalf of Melbourne Water. The upgrade works will ensure the retarding basin continues to reduce the risk of flooding to the community.

Why are we upgrading the Long Island retarding basin?

Melbourne Water has over 200 retarding basins that we regularly assess for risks, conduct maintenance on, and upgrade as necessary. The Australian National Committee on Large Dams (ANCOLD) guidelines represents the best Australian and international engineering practice in the safe design, management and operation of dams. We use these guidelines to manage our retarding basins. The Long Island retarding basin has recently been assessed against the ANCOLD guidelines. This assessment has shown that upgrade works are necessary to ensure the retarding basin continues to reduce flood risk and operate safely for the community.

What to expect during construction?

The upgrade works will be carried out by John Holland-KBR Joint Venture on behalf of Melbourne Water. These works will include:

  • removal of trees, root ball excavation and backfill of embankment
  • sand filter trench excavation and backfill
  • embankment hardening
  • embankment crest capping
  • sheet pile installation for foundation cut-off wall

We will do everything possible to minimise disruption during construction, however it is likely that nearby residents will notice:

  • large trucks and machinery working around the retarding basin.
  • worker amenities set up within the construction area
  • some noise, dust and vibration from construction works
  • removal of trees and vegetation from the retarding basin embankment - trees and vegetation in other parts of the reserve will be retained
  • construction traffic and equipment will enter and exit the site via Long Island

Map showing where upgrade works will be taking place on the Long Island Retarding Basin
Area of works on the Long Island Retarding Basin

Timing of works

This project is now complete.

Wildlife handling

A qualified wildlife handler, with 25 years’ experience in zoology and ecology, has been hired by the project team as a precaution and to put community concerns at ease.

The handler has a permit under the Wildlife Act 1975 and we are operating under this Act. The wildlife handler will remain onsite for the duration of the tree removal works (if required).

Melbourne Water's wildlife Management process

  • A Flora and Fauna assessment was completed in the design phase
  • A wildlife pre clearance check will be completed prior to construction, including checking the site for fauna and marking trees likely to have habitat. If fauna is found the wildlife handler will be on site for the duration of the tree removal works.
  • The wildlife handler will complete a walk through on the day of the tree removal and again checked all hollows to ensure no wildlife had moved in, including checking higher location via a boom (cherry picker).
  • If fauna is found in a tree, the wildlife handler will attempt to catch it (without chasing or causing it distress). If it can’t be caught the wildlife handler will encourage the fauna to move. If this isn’t possible the contractors will move to the next tree and return to try again.
  • To check for micro bats, the wildlife handlers have been lifting the bark and checking in hollows and cracks. If any micro bats are found they are bagged, put in a dark, quiet, cool area and released at dusk, preferably on a mirror image tree.
  • Nest boxes will be installed on site as they create more habitat.
  • Nests in trees that are being removed will be relocated. If they are intact, they will be put next to the nest box and if not, the remnants are strategically placed in the nest boxes in trees to encourage the fauna into other trees.
  • Any hollow trees will be retained for fauna habitat
  • A fauna ladder is being considered for connectivity for arboreal species.
  • Flowering eucalyptus tree branches are being retained as a food source for birds and some mammals (and being donated to wildlife carers/shelters).
  • Seeds are being collected from Eucalypt and Melaleuca trees and being extracted, cleaned and processed to use for propagation for the local area. They will be donated to Frankston City Council’s indigenous nursery.

Further information

Your feedback

Phone: 1800 096 546 Option:5 Long island retarding basin or email

Email: [email protected]

Last updated:
10 July 2019