Building a hydrologic foundation for tropical watershed management

Area of Science:

• Hydrology
• Tropical Ecosystems
• Water Resource Management

Background:

• Tropical watershed hydrology is complex, influenced by rainfall variability, high evapotranspiration, and forest canopy dynamics.
• Previous water budgets for El Yunque National Forest (EYNF) included external withdrawals and estimated volumes, limiting their accuracy for internal management.

Purpose of the Study:

• To develop an empirical hydrologic foundation for water management within EYNF.
• To provide realistic water withdrawal estimates for the EYNF.
• To inform decisions protecting native aquatic species.

Main Methods:

• Developed mass-balance and observation-based water budgets for nine EYNF watersheds.
• Utilized remotely sensed rainfall data, gaged streamflow, and operational municipal water withdrawal data.
• Confined water budget analysis to within EYNF boundaries, using conservative withdrawal estimates.

Main Results:

• Established novel water budgets specific to EYNF watersheds.
• Generated more conservative and realistic estimates of water withdrawals within the EYNF.
• Highlighted the importance of considering withdrawal impacts at various probability scales.

Conclusions:

• This research provides a critical hydrologic basis for sustainable water management in the EYNF.
• The findings underscore the challenges and necessity of accurate water budget assessments in tropical ecosystems.
• Considering ecological flow needs, especially for migratory species, is vital for preventing over-abstraction.