Assessment of climate change on river streamflow under different representative concentration pathways

Area of Science:

• Hydrology and Climate Science
• Environmental Modeling
• Water Resource Management

Background:

• Climate change and greenhouse gas emissions significantly alter hydrological cycles, especially in arid/semi-arid regions.
• Impacts on water resources, agriculture, soil, and flood risk necessitate detailed regional assessments.
• The Zarrineh River Basin in Iran faces potential water resource challenges due to these climatic shifts.

Purpose of the Study:

• To investigate the impacts of climate change on streamflow in the Zarrineh River Basin.
• To project future streamflow alterations across three decadal intervals up to 2099.
• To inform adaptation and mitigation strategies for water resource management.

Main Methods:

• Utilized four General Circulation Models (GCMs) under distinct Representative Concentration Pathways (RCPs).
• Generated daily temperature (Tmax, Tmin) and precipitation data from GCMs.
• Employed the Soil and Water Assessment Tool (SWAT) to simulate streamflow changes.

Main Results:

• Projected a decline in annual precipitation and maximum temperatures (Tmax), with a notable increase in minimum temperatures (Tmin).
• Average precipitation is expected to decrease from 0.77 mm (1985-1994) to 0.28-0.42 mm by 2090-2099.
• Simulated streamflow at the basin outlet shows a significant reduction from 52 m³/s to a range of 20-41 m³/s by 2090-2099.

Conclusions:

• Climate change projections indicate a substantial decrease in streamflow within the Zarrineh River Basin.
• The GCM with the highest temperature gradient predicted the lowest streamflow, emphasizing temperature's role.
• Findings underscore the urgent need for adaptive water management strategies in response to diminishing water resources.