Global‐scale river network extraction based on high‐resolution topography and constrained by lithology, climate, slope, and observed drainage density

• Published in: Geophysical research letters 2017-03, Vol.44 (6), p.2773-2781
• Main Authors: Schneider, A., Jost, A., Coulon, C., Silvestre, M., Théry, S., Ducharne, A.
• Format: Article
• Language: English
• Subjects: Assessments; Calibration; Climate; Climate models; Density; Dependence; Digital Elevation Models; Drainage; Drainage area; Drainage density; Drainage water; Earth Sciences; Elevation; Environmental factors; Freshwater; Geophysics; global scale; Groundwater; Groundwater flow; High resolution; Lithology; Mathematical models; Networks; Pixels; Resolution; river network extraction; River networks; Rivers; Sciences of the Universe; Slope; Slopes; Water currents
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1002/2016GL071844

To improve the representation of surface and groundwater flows, global land surface models rely heavily on high‐resolution digital elevation models (DEMs). River pixels are routinely defined as pixels with drainage areas that are greater than a critical drainage area (Acr). This parameter is usually uniform across the globe, and the dependence of drainage density on many environmental factors is often overlooked. Using the 15″ HydroSHEDS DEM as an example, we propose the calibration of a spatially variable Acr as a function of slope, lithology, and climate, to match drainage densities from reference river networks at a 1:50,000 scale in France and Australia. Two variable Acr models with varying complexities were derived from the calibration, with satisfactory performances compared to the reference river networks. Intermittency assessment is also proposed. With these simple tools, river networks with natural heterogeneities at the 1:50,000 scale can be extracted from any DEM. Key Points We propose simple models for global river network extraction coherent with a 1:50,000 scale and first‐order intermittency assessment The resulting drainage density is spatially variable and offers an acceptable fit with observation‐based patterns On average, globally, the predicted drainage density is approximately 0.70 km–1, with approximately 30% intermittent streams