Huarochirí and Canta provinces, Peru
#00203
Case study of
#00193 Revive traditional rainwater-harvesting and recharge structures through village labor and ownership
Implementer
Campesino communities with Aquafondo, The Nature Conservancy and CONDESAN
Timeline
Since Jan 1, 2015
Location
Description
Amunas are pre-Inca infiltration canals in the Peruvian highlands that divert wet-season streamflow onto permeable slopes, where water infiltrates and resurfaces downslope months later, extending dry-season availability. Since around 2015, campesino communities in Huarochiri and Canta provinces restored these canals with facilitation from Aquafondo, The Nature Conservancy and CONDESAN. Financing flows through Peru's MERESE mechanism, which earmarks approximately 1 percent of Lima's water tariffs for upstream ecosystem services, giving mountain communities a durable revenue stream for ongoing maintenance. Approximately 86 km of canals have been rehabilitated. A 2019 dye-tracer study (Nature Sustainability) confirmed a median water residence time of ~45 days before resurfacing, and modelling suggests scaling could raise Lima's dry-season flows by ~7.5 percent.
Metrics
4Funding
Lessons learned
- The MERESE tariff mechanism (~1% of Lima water tariffs) provides upstream communities a recurring revenue stream that survives NGO exit — directly addressing the maintenance-funding gap common to recharge programs.
- Independent hydrological quantification (dye tracers, published results) was essential to convert a traditional practice into a bankable water-supply option; replicators should budget for rigorous measurement before seeking large-scale finance.
- The model requires a large downstream water utility with a direct financial stake in dry-season flow to anchor the payment-for-ecosystem-services mechanism; identify that anchor institution before designing the finance structure.
Documented Jul 24, 2026