Effect of Topographic Data Accuracy on Watershed Management

Area of Science:

• Geosciences
• Geomorphology
• Hydrology

Background:

• Digital Elevation Models (DEMs) are crucial for terrain analysis, geomorphology, and hydrology.
• Various DEM sources exist (SRTM, GTOPO30, ASTER GDEM) with differing accuracies and resolutions.
• High-resolution DEMs offer accuracy but demand significant processing time.

Purpose of the Study:

• To analyze the impact of different DEMs on watershed geomorphological properties.
• To provide guidelines for selecting the most suitable DEM for accurate and efficient analysis.
• To compare the accuracy of SRTM, GTOPO30, and ASTER GDEM.

Main Methods:

• Utilized three software programs: Watershed Modeling System (WMS), Global Mapper, and Google Earth.
• Conducted three case studies to assess DEM accuracy.
• Employed high-resolution Google Earth satellite images as a reference for comparison.

Main Results:

• SRTM DEM demonstrated the highest accuracy at 95% across all case studies.
• ASTER GDEM achieved 87% accuracy.
• GTOPO30 exhibited 80% accuracy.

Conclusions:

• SRTM DEM is recommended for accurate and time-efficient watershed geomorphological analysis.
• DEM selection significantly impacts the precision of geomorphological property extraction.
• Users should consider DEM accuracy and resolution trade-offs for their specific applications.