Modeling River Discharge Using Automated River Width Measurements Derived from Sentinel-1 Time Series

Abstract

Against the background of a worldwide decrease in the number of gauging stations, the estimation of river discharge using spaceborne data is crucial for hydrological research, river monitoring, and water resource management. Based on the at-many-stations hydraulic geometry (AMHG) concept, a novel approach is introduced for estimating river discharge using Sentinel-1 time series within an automated workflow. By using a novel decile thresholding method, no a priori knowledge of the AMHG function or proxy is used, as proposed in previous literature. With a relative root mean square error (RRMSE) of 19.5% for the whole period and a RRMSE of 15.8% considering only dry seasons, our method is a significant improvement relative to the optimized AMHG method, achieving 38.5% and 34.5%, respectively. As the novel approach is embedded into an automated workflow, it enables a global application for river discharge estimation using solely remote sensing data. Starting with the mapping of river reaches, which have large differences in river width over the year, continuous river width time series are created using high-resolution and weather-independent SAR imaging. It is applied on a 28 km long section of the Mekong River near Vientiane, Laos, for the period from 2015 to 2018.

Spatiotemporal Characterization and Analysis of River Morphology Using Long-Term Landsat Imagery and Stream Power

“…Based on Equation ( 14), the river width directly relates to flow discharge and is inversely related to the sediment discharge. Therefore, decreasing the flow discharge of the Karun River can be a reason for the shrinkage in the river width, which is similar to the findings of Mengen et al (2020) [54] on the Mekong River and Byishimo et al (2014) [55].…”

Spatial Distributions of At‐Many‐Stations Hydraulic Geometry for Mountain Rivers Originated From the Qinghai‐Tibet Plateau

“…proposed an AMHG-based remote sensing discharge retrieval algorithm, which works for mass-conserved reaches and produced errors within 20%-30% of in-situ measured discharge in different types of rivers. and decile thresholding discharge estimation method developed by Mengen et al (2020) contribute to a significant improvement in discharge estimation. However, estimation accuracy of the aforementioned method using only satellite-observed cross-sectional width data is not always guaranteed if no previous estimates were made (Hagemann et al, 2017;Brinkerhoff et al, 2020).…”

“…Feng et al (2019) affirmed the possibility of estimating discharge independent of ground-based measurements with BAM. Recently, geo-BAM method proposed by Brinkerhoff et al (2020) and the decile thresholding discharge estimation method developed by Mengen et al (2020) contributes to a significant improvement in discharge estimation. However, estimation accuracy of the aforementioned method using only satellite-observed cross-sectional width data is not always guaranteed if no previous estimates were made (Brinkerhoff et al, 2020;Hagemann et al, 2017).…”

HydroWidth: A small‐scale approach to calculate river width and its variability

“…In general, sparse river width measurements are unable to capture the variations of a river channel and how the river width varies over space and time (J. Yang et al, 2020). The segment method poses similar problems as averaging values eliminates small variations in width and, depending on the application, the spacing and delineation of segments greatly influence the results (Mengen et al, 2020). Clearly, measuring river width is a process that lends itself to geodata‐based workflows, substituting costly in situ measurements.…”