Impacts of sediments from urban and rural stormwater on stream health

Progress towards zero impact from urban development

Background

Fine sediments mobilised by the channelisation of rivers have been identified as a significant threat to environmental values in Western Port, particularly important seagrass habitats (Melbourne Water, 2018). The largest sediment sources are thought to be from the stream bank and gully erosion. Recent evidence suggests that changes in agricultural practices and urban development are also impacting catchment sources. Associated with sediments are pollutants which can have significant ecological impacts on the flora and fauna of the waterways and bays. 

Approach

This case study project aims to:

  • Understand the concentrations and effects of pollutants attached to sediments generated from urbanising areas relative to existing urban and agricultural areas in the Westernport catchment.
  • Determine if current sediment controls are sufficient and if not, recommend options for increasing the protection of waterway health during urban development.

The project is a collaboration with Melbourne Waterway Research-Practice Partnership (MWRPP) Project B2.  

Stage 1: Pre-development

Herbicides

Fungicides

Nutrients

Stage 2: Bulk earthworks

0 - 9 months

Low level of Pollutants

Stage 3: House construction

9 - 12 months

Insecticides

Stage 4: Landscaping

1-4 years

Increase in Insecticides

Heavy metals?

Stage 5: Complete

4+ years

Increase in Heavy Metals

Insecticides

 

Progress to date

Sampling of sediments within the local creek and wetlands in an urbanising estate in Officer has begun.  Monitoring of pollutants within this estate will continue to occur quarterly until 2022 as well as additional monitoring  of two urbanising estates in the area

Expected Outcomes

  • Understanding of the effectiveness of current sediment control methods during urban development to reduce sediments and associated pollutants to streams, wetlands, estuaries and the bay across the Westernport catchment
  • Determining the relative contribution of sediment loads generated during urban development compared to existing urban and agricultural areas to support achievement of Healthy Water Strategy and EPA State Environmental Protection Policy objectives for sediment load reductions to Western Port

Project Team

RMIT A3P: Claudette Kellar, Kathryn Hassell, Vin Pettigrove, Dan MacMahon, James Oliver, Michael Clark, Monica Tewman.

UoM MWRPP: Kathy Russell, Geoff Vietz, Peter Poelsma, Matt Burns, Tim Fletcher, Rob James, Darren Bos.

MW: Trish Grant, Alison Rickard, Penny Rogers, Leigh Smith, Marion Urrutiaguer, Rowan Hore, Michael Godfrey, Birgit Jordan, Rhys Coleman, Slobodanka Stojkovic.

Expected Completion 2023

Contact   claudette.kellar@rmit.edu.au or 9925 4682 or kathryn.hassell@rmit.edu.au on 9925 4647

Resources: EPA 2023 Construction demolition guideline 1834 - Guidance Sheet 4: Termite pesticide starts on page 89

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Acknowledgement of Country

RMIT University acknowledges the people of the Woi wurrung and Boon wurrung language groups of the eastern Kulin Nation on whose unceded lands we conduct the business of the University. RMIT University respectfully acknowledges their Ancestors and Elders, past and present. RMIT also acknowledges the Traditional Custodians and their Ancestors of the lands and waters across Australia where we conduct our business - Artwork 'Luwaytini' by Mark Cleaver, Palawa.

aboriginal flag
torres strait flag

Acknowledgement of Country

RMIT University acknowledges the people of the Woi wurrung and Boon wurrung language groups of the eastern Kulin Nation on whose unceded lands we conduct the business of the University. RMIT University respectfully acknowledges their Ancestors and Elders, past and present. RMIT also acknowledges the Traditional Custodians and their Ancestors of the lands and waters across Australia where we conduct our business.