Manage Hydrologic Fluxes Instead of Land Cover in Watershed Services Projects

Payments for Watershed Services (PWS), Water Funds, and other payment schemes intended to increase the delivery of hydrologic ecosystem services have great potential for ensuring water resources for downstream beneficiaries while improving livelihoods for upstream residents. However, it is often ambiguous which land-management options should be promoted to enhance watershed service delivery. In many watershed investment programs, specific land covers are promoted as proxies for water service delivery. This approach is based on assumed relationships between land cover and water service outcomes. When land cover does not sufficiently describe ecosystem characteristics that affect water flow, however, desired water services may not be delivered. The use of land cover proxies is especially problematic for watershed investments in the tropics, where many projects are located, because these proxies rely on generalizations about landscape hydrology established for temperate zones. Based on an extensive review of hydrologic fluxes in the high-elevation tropics, we argue that direct management of hydrologic fluxes is a good design for achieving quantifiable results. We use case studies from sites in the Caribbean and Latin American tropics to illustrate how designers of watershed payment projects can manage hydrologic fluxes. To do so, projects must explicitly articulate the water service of interest based on the specific social setting. Projects must also explicitly account for the particulars of the geographic setting. Finally, outcomes must be assessed relative to water services delivered under an alternative land use or land cover scenario.