Concrete Solutions

This page explores the possibilities for removing, altering or covering the concrete sections of the creek, with the aim of eventually naturalising the entire length of the creek. Where possible, costings have been included. Inclusion DOES NOT indicate endorsement by FoMPC.

1. Concrete Removal

Concrete would be completely removed and taken away. Rocks would be used to replace the concrete, to create a semi natural state that would be attractive but resistant to erosion. Estimated cost per km: million(s)

2. Concrete “Disruption”

This would involve breaking up the concrete in some way, in order to “let nature take its course”. Eventually grass and trees would grow through the broken concrete and create a more natural appearance, however the creek would maintain its regimented look, with straight lines and regular curves instead of a random path. One possible suggestion, from Prickly Pear:

Estimated cost per km: 1000s?

3. Concrete Cover up

Would involve leaving the concrete in place and covering it up using:

· Water – create small concrete dams every 100m or so, to raise height to cover concrete base, then put down wire trestle, concrete reinforcement steel sheets, gravel holders etc on the diagonal side sections, to allow grass etc to grow down from banks.
· Rocks – Either by breaking up concrete first, or applying some sort of grid of wire, then place large or medium size rocks to cover concrete. Eventually silt would get caught in rocks and vegetation would grow.
· Pebbles, clay, dirt etc
In all cases many trees and shrubs would be planted on slopes to soften creek and help prevent erosion.

4 “Two Creeks”: high and low flows

The Problem

  • The Moonee Ponds Creek currently has two 3.5 kilometre long sections of concrete-lined narrow channel, created in the 1960s and 70s, chiefly to facilitate the building of the Tullamarine freeway.
  • These concrete sections have come to be seen as an eyesore by the increasing number of people who now walk and cycle along the banks of the creek, and there is a public demand for a more “natural” appearing creek, with its associated environmental benefits.
  • The cost of removing the concrete would, however, be tens of millions of dollars, and any resulting more natural creek would be more susceptible to flooding.
  • Safety concerns about the new creek at times of high-flow would also face community resistance.

The Solution

These problems could be solved by creating two creeks; a new one above-ground that would have a constant low to medium flow, and one underground created from the concrete of the old creek, which would handle high-flow events.  As the current creek floods above the level of the concrete walls only rarely, the new surface creek would only occasionally flood.

Phase one would involve the placing of large concrete slabs over the existing concrete sections of creek; these slabs could rest on the top of the walls of the existing concrete. Possibly props or a central support could be used to ensure slabs do not collapse. Work could proceed while the creek continued to flow.

Phase two would involve landscaping the newly-created sections, all work to be done before flow resumed above-ground. Various landscapes could be created including Ponds, Wetlands, walking tracks, play areas, etc. Possibly, the above-ground sections could be the responsibility of councils and local residents, while the underground sections would remain the preserve of Melbourne Water.

Phase three would involve the creation of a reservoir at the start of the concreted section. Narrow pipes running through the rocky surrounds would create a constant low to medium flow above the surface, and a spillway would take water underground to the existing creek in times of high flow.

When work was completed, water would begin flowing above ground. The result would be a meandering stream, or a chain of ponds and wetlands. New vegetation could filter water that flows into the creek from surrounding suburbs.

Benefits

This scheme has a number of advantages over the alternatives:

  • A “chain of Ponds” creek could be created above ground with constant low flow of water, close to ground level, with minor risk of flooding and all sorts of possibilities for creating natural habitats and recreational areas.
  • Melbourne Water would get to preserve an important asset they have spent a great deal of money and effort creating, only it will be placed underground.
  • The risk of flooding would be diminished to the satisfaction of neighbouring residents, and much of the danger of above-ground high flows of water would be eliminated.
  • The scheme creates enormous possibilities for a safe, interesting, beautiful green linear park, attractive and safe for visitors.
  • The creek would be closer to the surrounding street level, meaning fewer steep banks. Perhaps with small bridges or stepping stones every 50 metres or so, crossing would be much easier at numerous places along the creek.
  • The plan allows work to proceed during all phases without having to dam off the creek to stop flow, producing cost savings.
  • The scheme creates opportunities for local residents to contribute to the landscape planning and participate in creating the new above-ground creek.
  • The new creek would be a focus point for the community, instead of something it turns its back on, as it has in the past.

Estimated cost, per 3.5km section: $    million