Waterway Investment prioritisation The Merri Creek Catchment Pilot Study

The question… “Can we deliver better value to the community by integrating our water management programs and services?” Hypothesis: By integrating water agencies and local councils’ waterway investments, greater value can be provided to the community in terms of (1) improved waterway health and (2) provision of amenity Approach: Undertaking a wholistic waterway investment review exercise of existing and planned waterway health and amenity programs within a selected pilot catchment.

Inflow & Infiltration

Emergency Relief structure

Historical approach Grey Infrastructure Large sewer duplications

Current Planned investment – 5 years Yarra Valley Water Melbourne Water Sewer main duplications TOTAL EXPENDITURE ~ $19M Revegetation Community grants Weed management Stabilisation Desilting TOTAL EXPENDITURE ~ $5M Councils Parkland and stream management programs Education programs – Stormwater and site management practices Stormwater runoff programs / local WSUD assets Local Stormwater harvesting and reuse projects TOTAL EXPENDITURE ~ $1M Only place more than one slide per page if you are making comparisons between them. Remember to reference the author. For tips on using graphs in your presentations see: http://blog.hubspot.com/marketing/data-graph-design-powerpoint-tips-ht#sm.000002215dedbwfb3zzbnd2q4mquq

Community Expectations Only place more than one slide per page if you are making comparisons between them. Remember to reference the author. For tips on using graphs in your presentations see: http://blog.hubspot.com/marketing/data-graph-design-powerpoint-tips-ht#sm.000002215dedbwfb3zzbnd2q4mquq

Understanding the Impact Three key waterway attributes were assessed: Public Health Environment Amenity/Aesthetics

PUBLIC HEALTH What do we know about the Merri Creek? Too much background E.coli for primary contact Too much E. coli during wet weather for secondary contact Wastewater overflows in wet weather are very infrequent (less than 1 per year) Large dilution during wet weather leads to sewer spills due to hydraulic capacity having minimal impact Urban storm water contributes 99% of all pollutant loads

PUBLIC HEALTH Key Conclusions? Primary or secondary contact in Merri Creek is not practically achievable regardless of wastewater infrastructure upgrades Wastewater overflows are very low risk for contact recreation in Yarra River and Port Phillip Bay Complete elimination of wastewater overflows would result in no measurable benefits for practically achievable public health outcomes or mitigation of risk to the Yarra River and Port Phillip Bay Identification and rectification of illegal sewer to storm water connections is best public health risk mitigation measure for Yarra River and Port Phillip Bay There are other barriers to achieving secondary or primary contact standards in the Merri Creek – e.g. turbidity, toxicants, hydraulics, etc.

Aesthetics & Amenity Melbourne Water and Council’s contribute to vegetation management / enhancement Key risks to aesthetics and amenity include: Gross pollutants from Stormwater discharge (high frequency) Gross pollutants from wastewater overflows (low frequency) Odours in the Merri Creek haven’t been a key issue in the past and are considered low risk Turbidity / water murkiness is a key issue and vast majority of sediment loads come from stormwater

Environment Current Status: Urban sections of Merri Creek are highly degraded and typical for an urban stream Sediments contaminated with heavy metals and pesticides which represent the main threats to plant & animal life Mixture of point source and diffuse pollution Primary Areas of Focus? Stormwater pollutant load reductions Source control measures Riparian vegetation enhancement.

Planned expenditure vs outcome Description Investment Outcome Benefit Sewer Hydraulic Upgrades to meet current SEPP 1 in 5yr wet weather containment standard ~$19M (80%) Public Health (YR &PPB only) Very Low Capital program for vegetation management (ecological enhancement and some amenity) ~$1.5M (6.5%) Aquatic Life, Riparian vegetation, Aesthetics High Maintenance programs (vegetation and litter/debris/sediment removal) ~$1.8M (7.5%) Stormwater Runoff / WSUD / harvesting and reuse projects/capacity and education programs ~$1.4M (6%) Aquatic Life, Aesthetics High (local) TOTAL ~ $25M

Alternative approaches Stormwater: Strategic stormwater to sewer diversion Additional gross pollutant traps Raingardens Community group grants Riparian Vegetation Sewer: ERS screening Sewer illegal connection identification and rectification Inflow and infiltration rectification

Next steps Currently monitoring to establish baseline and determine target areas: Litter surveys Drain surveys Water quality monitoring Working towards regulatory approval (EPA) for revised approach Further community consultation

Questions