WATER

Interventions on freshwater and wastewater: treatment systems, river and wetland restoration, stormwater management, water supply protection, and sanitation infrastructure with an environmental discharge outcome. A record enters this class when the intervention's primary stated aim is the quality, availability or safe return of water.

One record. C4P-WTR-0001, Indonesia's SANIMAS program: 21,832 neighborhood-scale decentralized wastewater systems built 2003-2019 at a cumulative US$941.6 million (nominal, 2002-2019). Graded T3 for transferability and E2 for evidence, with outcome status failed_social. The treatment technology largely worked: 92% of 99 tested early systems met the then-applicable BOD standard of 100 mg/L (2011). Use collapsed after handover to volunteer community groups: median usage was 100 people per site against a design basis of 250 to 500, one third of systems had no active management group, and 71% of systems in the 2020 evaluation cohort older than two years had never been desludged.

One national program, however large, is still one record. It documents a specific handover model failing at scale under three independent evaluations. It does not establish that community-managed sanitation fails in general; the same evaluations identify the conditions under which sites performed acceptably.

The class has no success-side record yet. Candidate records under research include decentralized treatment programs with co-management models of the kind the SANIMAS evaluations recommend, where post-handover performance data exists.