Case Study: City of St. Helena achieves transparent, data-driven water planning and robust supply forecasts with Lumina Decision Systems' Analytica

City of St Helena - Customer Case Study

The City of St Helena faced contentious debate over whether its water supply could support future growth amid variable rainfall, a reservoir that provides ~50% of supply, an uncertain contract with the City of Napa (~30%), and limited groundwater (~20%). To inform its state-required general plan update and defuse pro/anti-growth tensions, the City enlisted modeling with Analytica, using tools from Lumina Decision Systems to quantify supply risks and test alternative water policies.

Consultant Tim Neiman built a transparent Analytica model (from Lumina Decision Systems) that replicated the city’s deterministic analysis, nested the three water sources, imported historic precipitation, and ran large-scale Monte Carlo simulations and climate-change scenarios to forecast supply and demand under different growth, conservation, and recycled-water assumptions. The model improved planning efficiency versus spreadsheets, increased stakeholder buy-in by making assumptions explicit, and helped inform the City Council’s discussion and eventual approval of new water-usage policies.

City of St Helena

Tim Nieman

Decision Analysis Consultant