Demand scenarios and validation
Reconciled development inputs with the central utility forecast, testing timing, persistence, peak demand, water-intensive uses, programme phasing and reuse availability.
Anonymised case study · Water resource strategy
Desalination supply phasing and techno-economic appraisal.
An engineering-led assessment for a large coastal development, bringing demand scenarios, supply configurations, hydraulic interfaces and whole-life economics into a decision-ready investment pathway.
- Scope
- Desalination, supply phasing and reuse
- Evidence
- Demand, system modelling and whole-life cost
- Output
- Sequenced investment and delivery gates
The decision
How can supply continuity be protected while major desalination investment is released only when demand and delivery readiness justify it?
A fast-growing coastal development needed a strategy for early construction, staged urban and industrial demand, and eventual transition to permanent regional infrastructure. The appraisal turned those connected constraints into a controlled pathway rather than a single, fixed asset choice.
The appraisal
A controlled comparison from demand to investment action.
The study combined the questions that materially shaped the preferred route: when demand would arrive, how supply could be configured, what system interfaces were required, and which timing created the most defensible whole-life outcome.
Supply configurations and system interfaces
Tested four supply configurations across the complete system boundary: source, treatment, intake and discharge, storage, pumping, transmission, temporary supply and operations.
Whole-life cost and decision gates
Compared capital, temporary-supply exposure, operating cost and discounted whole-life implications alongside asset readiness, delivery duration, environmental requirements and continuity.
Multi-scenario modelling
The preferred route was tested against changing demand, not a single forecast.
The model considered a base demand outlook alongside earlier, later and moderated exceptional-demand cases. Each was tested against alternative supply configurations before a delivery pathway was selected.
01 · Demand cases
- Base forecast
- Earlier or accelerated demand
- Later or moderated demand
02 · Supply paths
- New production capacity
- Split source configuration
- Established-source expansion
- Integrated reuse
03 · Decision tests
- Permanent-capacity timing
- Temporary-supply exposure
- Transfer-network readiness
- Whole-life value
What this changedAn option that appeared efficient under one demand curve could be exposed when the timing or magnitude of exceptional demand changed. The model made those decision sensitivities explicit before major capital was committed.
Portfolio noteThis is an anonymised synthesis of the modelling logic. Scenario labels, timings, locations, client data and commercial values have been removed.
Whole-life comparison
The preferred pathway considered capital timing, operating exposure and future flexibility together.
Demand start date, peak magnitude, commissioning, temporary-supply duration, transfer readiness and reuse availability were treated as decision sensitivities, not background assumptions.
Recommended delivery pathway
Bridge defined gaps, validate demand, then release permanent capacity in stages.
The resulting pathway retained the established source for the near-term base, used temporary supply where needed, set a demand and readiness gate for incremental capacity, and advanced new production and transfer infrastructure only for sustained demand. Non-potable reuse was enabled early as a capacity-management lever.
Decision governance
Engineering confidence was kept visible through the delivery process.
The recommendation was supported by an assumption register that recorded source, owner, confidence, impact and validation path. This made the dependencies on forecast, approvals, network readiness and construction progress explicit.
Validate
Confirm the sustained-demand case, asset and network capacity, and temporary-supply requirements before releasing expansion.
Commit
Confirm delivery readiness, environmental approvals, transfer interfaces and construction progress before committing major permanent infrastructure.
Keep the pathway adaptable
Use sensitivity testing and a live evidence register to respond to changing demand, reuse availability and delivery dates without losing the strategic intent.