Water security, global change and land-atmosphere feedbacks

Area of Science:

• Hydrology
• Environmental Science
• Climate Science

Background:

• Competing pressures on water resources necessitate understanding future water balances under environmental change.
• Effective policy planning requires a robust, scientifically rigorous evidence base for water resource management.
• Environmental change encompasses climate change, land-use change (e.g., deforestation), and human interventions (e.g., dams).

Purpose of the Study:

• To examine the role of land surface models in providing a scientific basis for resource management decisions amidst environmental change.
• To review recent developments in land surface hydrology modeling.
• To identify key areas for improvement in land surface and hydrology models for hydrological applications.

Main Methods:

• Analysis of current land surface and hydrology models, identifying variability and areas for improvement.
• Examination of specific hydrological processes including groundwater representation, human interventions (dams, irrigation), uncertainty quantification, and water reuse.
• Demonstration through examples of reciprocal impacts between water use changes and climate.

Main Results:

• Current land surface and hydrology models exhibit significant variability, indicating a need for improved specification and parameterization of basic processes.
• Key areas for model improvement include groundwater representation, human interventions, uncertainty quantification, and understanding multiple water uses.
• Changes in water use can have significant reciprocal impacts on regional climate, effects that are increasingly being investigated.

Conclusions:

• Land surface models are essential tools for informing water resource management decisions in the face of environmental change.
• Improvements in model representation of hydrological processes and human interventions are critical for accurate predictions.
• Understanding the interconnectedness of water systems, climate, and ecosystem services is vital for sustainable resource management, particularly in complex environments like wetlands.