Integrated Stormwater Treatment Business Case & MCA
A multi-criteria assessment (MCA) of stormwater treatment options, focusing on compliance, risk mitigation, and whole-of-life cost analysis.
MCA Results
Multi-Criteria Assessment — Why Option 3 Wins
Option 3 is the ONLY option addressing BOTH water quantity AND water quality — and it achieved the highest score across all three assessment categories.
Risk Summary
Residual Risk After Mitigation
Option 3 is the ONLY option with NO residual risks above MEDIUM after mitigation. No other option achieves this profile.
Residual Risk Comparison — Post-Mitigation
Financial Summary
Discounted Total Cost Analysis
Stormwater infrastructure generates no direct revenue — value is captured through avoided fines ($277,888/yr), regulatory compliance, and operational enablement.
Option 1 (Do Nothing) incurs $277,888/yr in penalties — inaction is the most expensive choice.
Discounted Whole-of-Life Cost Comparison
Do Nothing
Min. Compliance – Qty Only
Integrated Treatment
Advanced Treatment + Reuse
Value Justification
Avoided Fines
$277,888/yr avoided under Option 3
Regulatory Compliance
Licence conditions met; enforcement risk eliminated
Operational Enablement
STP Stage 6 expansion can proceed without stormwater constraint
Recommended: Option 3
Integrated Treatment — Water Quantity + Quality
Only Full Compliance Solution
Option 3 is the ONLY option that resolves BOTH water quantity AND water quality non-compliance. Partial solutions leave regulatory risk unresolved.
Lowest Whole-of-Life Cost
At $771,485 discounted total, Option 3 is the most cost-effective compliant solution. Do Nothing costs more through $277,888/yr in ongoing fines.
Best Risk Profile
No residual risks above Medium after mitigation. No other option achieves this. Option 3 eliminates enforcement, environmental and operational risk.
Full Strategic Alignment
Aligns with both the Solid Waste Strategy 2024 and Towards Zero Waste Plan 2025–2028. Option 3 is not just compliant — it's the strategically right investment.
Option 3 delivers compliance, lowest cost, best risk, and strategic fit — the decision is clear.
Implementation Plan
18-Month Delivery Programme
Open market tender model
Two-stage funding release
Critical path: EA amendment drives design timeline
Co-delivered with STP Stage 6 works
Funding Approval & Initiation
Business case approved. Project charter established. Funding released — Stage 1. Stakeholder notification and project team mobilised.
Design & EA Amendment
Detailed design completed. Environmental Authority amendment lodged and approved. Procurement documentation prepared.
Procurement & Tender
Open market tender released. Contractor evaluation and selection. Second-stage funding released. Contract awarded.
Construction & Commissioning
Construction of integrated stormwater treatment system. Testing and commissioning. Handover and compliance verification. Regulatory sign-off.
Critical path: EA amendment (Months 1–7) determines overall programme — delays here directly impact construction start.
- stormwater-management
- business-case
- environmental-compliance
- risk-assessment
- infrastructure-planning
- water-quality