Water Quality in Melbourne’s

waterways – an urban context

Waterwatch Presentation

Julia Vanderoord

Waterwatch Coordinator

North East Melbourne Waterwatch

River and Creek ConditionsSource: Port Phillip & Westernport Regional River Health Strategy

A recent analysis shows that 25% of rivers and creeks in

Melbourne are in good or excellent condition

and 75% are in moderate to very poor.Results reflect land use

patterns

What do the results mean?

These results reflect the major land use patterns. The rivers and creeks located in mountainous, forested areas are in excellent to good condition. Large parts of these areas are protected for water supply purposes. Condition deteriorates progressively downstream as a result of: •poor quality drainage and runoff from urban and agricultural land •weeds •bed and bank erosion •loss of in-stream habitat •presence of barriers to fish migration •modified flows in many rivers and creeks, which have resulted from:

–Increased urbanisation and land clearing –The extraction of water for urban and agricultural uses.

Lets explore each of these items in more detail……

•One of the biggest issues in Melbourne•60,000 truckloads of litter (50% of this is cigarette butts) and other pollutants enter our waterways each year via the stormwater system•Velocity- leads to bank instability and erosion

•Effects?•Suggested actions to improve?

1. Poor quality drainage and runoff from urban and agricultural land

(stormwater)

•Loss of habitat•Some weeds have drastic effects on riparian system (ie willows, salvinia, alligator weed)•Sedimentation•Shading out of ground level and in-stream•Changes to flow (ie willows)

•Effects?•Suggested actions to improve?

2. Weeds

•Caused by:– high intensity stormwater flows, poor engineered placement of drain openings–loss of infiltration areas (ie more concrete in catchments) increases velocity of water-loss of habitat- bare ground

•Effects?•Suggested actions to improve?

3. Bed and bank erosion

•Caused by:– straightening and de-snagging of streams (floods)-deepening of streams-draining and removal of wetlandsRemoval of rocks (riffles)-changes to flow regimes (ie flooding, drought)

•Effects?•Suggested actions to improve?

4. Loss of in-stream habitat

•Caused by:•Fast flows in concrete channels•Weirs & waterfalls•Dams, lakes, reservoirs•Bridges and culverts•Low flows (use of water for irrigation etc)

•Effects?•Suggested actions to improve?

5. Presence of barriers to fish migration

•Caused by:•Irrigation at inappropriate times•Reservoirs & dams•Drought•Farm dams

•Effects?•Suggested actions to improve?

6. Modified flows in many rivers and creeks

For further information:Melbourne Water Website: www.melbournewater.com.au

The Biodiversity management issues series (produced by DSE)

DSE website: www.dse.vic.gov.au

The River Landscapes series. (Land & Water Australia, Canberra,

Weblink: www.lwa.gov.au

Local Council websites

PPWCMA website: www.ppwcma.vic.gov.au

DPI website: www.dpi.vic.gov.au

Environmental indicators for Metropolitan Melbourne : www.aius.org.au/indicators