In January 2015, the Cantareira reservoir system — the principal source of drinking water for 9 million
residents of Greater São Paulo — fell below 5 per cent of its operating capacity. The drought that triggered
this crisis was exceptional, yet its roots were systemic: decades of deforestation in the surrounding watersheds
had eroded the natural sponge that once moderated rainfall into river flows. SABESP, the state water utility
responsible for the metropolitan area’s supply, faced a stark choice: invest billions in additional reservoir
capacity and pumping infrastructure, or restore the native Atlantic Forest vegetation across hundreds of
thousands of upstream hectares.
From Grey to Green – Financing Nature-Based Solutions in Public Enterprise
