Water Collection Strategy

The water collection strategy tests how Lahaina’s water system can perform under two extremes: chronic drought and acute flood. Rather than relying on one centralized source, the proposal distributes capture, storage, and overflow management across the mauka-to-makai landscape.

Principles

• Minimal landscape intervention keeps the system legible and grounded in existing topography.
• Distributed water capture spreads storage across ditches, ponds, and basins instead of concentrating risk in one piece of infrastructure.
• Water independence reduces pressure on the overstressed aquifer by retaining and reusing surface water.
• Cultural heritage is supported by restoring water logic that aligns with historical land-and-water stewardship patterns.

Actions

• Reopen or strengthen ditch networks to move water deliberately through the district. WSP’s 2024 survey identified 11 rehabilitable water-control structures at 1,000–3,000 feet elevation.
• Build storage ponds and retention basins — sized at 0.5 acres per 10 acres drainage area — that hold water in drought and slow water in flood.
• Limit public access in sensitive collection areas where hydrological performance and ecological recovery need protection.

Performance targets (see support image below)

The support image tests the proposed system against drought (< 10″ annual rainfall at coast) and flood (25-year peak rainfall event) scenarios. Key targets: 30% of non-potable demand met through captured water, emergency fire-suppression reserve independent of municipal supply, and aquifer recharge contribution moving toward long-term sustainability. Under the 2023 failure conditions (combined drought + fire + grid loss), the proposed layered system avoids the single point of failure that collapsed the existing network.