Forecasting streamflow and water availability in a Brazilian semi-arid watershed

Area of Science:

• Hydrology
• Climate Science
• Environmental Modeling

Background:

• Semi-arid regions face hydrological challenges due to climate variability and data scarcity.
• Hydrological modeling is crucial for understanding water dynamics and predicting future scenarios.
• Climate change impacts on hydrometeorological variables require detailed investigation.

Purpose of the Study:

• To assess a hydrological model's accuracy in simulating discharge in a Brazilian semi-arid mesoscale watershed.
• To evaluate the impact of reference evapotranspiration (ET0) changes on local water availability.
• To understand the relationship between ET0 trends and streamflow variations.

Main Methods:

• Utilized a hydrological model for discharge simulation.
• Analyzed model performance using Nash-Sutcliffe Efficiency (NSE), Coefficient of Determination (R²), and Root Mean Square Error (RMSE).
• Evaluated the effects of altered ET0 patterns on water availability.

Main Results:

• The hydrological model demonstrated high accuracy at an annual time step (NSE = 0.83, R² = 0.9, RMSE = 0.16 m³/s).
• Changes in ET0 exhibit a non-linear influence on watershed streamflow.
• A 15% increase in ET0 trend led to a 23% decrease in local water availability.

Conclusions:

• The validated hydrological model is a reliable tool for assessing water resources in semi-arid environments.
• Reference evapotranspiration is a critical factor influencing water availability in these regions.
• Projected increases in ET0 due to climate change pose a significant threat to water resources in semi-arid areas.