Water distribution based on SAR and optical data to improve hazard mapping.

Area of Science:

• Earth and Environmental Sciences
• Remote Sensing
• Hydrology

Background:

• Climate change is increasing extreme precipitation and drought events, causing rapid shifts in surface water bodies.
• Accurate and rapid mapping of hydrological changes is crucial for effective disaster risk reduction and emergency management.
• Regions with drastic hydrological changes require specialized methods for hazard assessment.

Purpose of the Study:

• To present an automatic method for mapping drought and flood hazards, especially in areas experiencing significant hydrological changes.
• To develop a system capable of rapid hazard mapping, even without optical data.
• To improve the accuracy of water body identification for better disaster management.

Main Methods:

• Utilized Sentinel-1/2 and Landsat satellite data for surface water extraction.
• Combined index-based analysis for optical data and the region-Otsu method for radar data to identify water bodies.
• Classified permanent and seasonal water bodies to establish a baseline for hazard identification.

Main Results:

• Demonstrated high similarity with existing products in case studies (Poyang Lake, Po River Plain, Indus River Plain).
• The method provides detailed insights into flood and drought-affected areas.
• Validated the capability for rapid mapping, independent of optical data availability.

Conclusions:

• The developed methodology effectively maps drought and flood hazards in regions with fluctuating hydrological conditions.
• This approach enhances emergency management and disaster risk reduction by mitigating errors from natural hydrological dynamics.
• The method offers a valuable tool for understanding and responding to water-related hazards in dynamic environments.