Discharge Estimation From Dense Arrays of Pressure Transducers

Self Cite

Avulsions change river courses and transport water and sediment to new channels impacting infrastructure, floodplain evolution, and ecosystems. Abrupt avulsion events (occurring over days to weeks) are potentially catastrophic to society and thus receive more attention than slow avulsions, which develop over decades to centuries and can be challenging to identify. Here, we examine gradual channel changes of the Peace-Athabasca River Delta (PAD), Canada using in situ measurements and 37 years of Landsat satellite imagery. A developing avulsion of the Athabasca River is apparent along the Embarras River-Mamawi Creek (EM) distributary. Its opening and gradual enlargement since 1982 are evident from multiple lines of observation: Between 1984 and 2021 the discharge ratio between the EM and the Athabasca River more than doubled, increasing from 9% to 21%. The EM has widened by +53% since 1984, whereas the Athabasca River channel width has remained stable. The downstream Mamawi Creek delta is growing at a discharge-normalized rate roughly twice that of the Athabasca River delta in surface area. Longitudinal global navigation satellite systems field surveys of water surface elevation reveal the EM possesses a ∼2X slope advantage (8 × 10 −5 vs. 4 × 10 −5 ) over the Athabasca River, and unit stream power and bed shear stress suggest enhanced sediment transport and erosional capacity through the evolving flow path. Our findings: (a) indicate that a slow avulsion of the Athabasca River is underway with potentially long-term implications for inundation patterns, ecosystems, and human use of the PAD; and (b) demonstrate an observational approach for identifying other slow avulsions at river bifurcations globally.Plain Language Summary Avulsions shift river courses and move water and sediment to new channels, which affect infrastructure, floodplains, and ecosystems. Slow avulsions take decades to develop and are more difficult to identify. Using on-the-ground measurements and 37 years of Landsat satellite imagery, we analyze gradual channel changes in the Peace-Athabasca River Delta (PAD), Canada. The Athabasca River is changing course such that more of its water enters its westernmost outlet, the Embarras River-Mamawi Creek (EM) channel. Multiple lines of evidence demonstrate that the EM channel has been gradually opening since 1982. Between 1984 and 2021, the water entering the EM channel increased from 9% to 21% of the river's total flow. Since 1984, the EM channel has widened by 53%, while the Athabasca River channel has remained stable. The delta forming at the EM mouth (i.e., Mamawi Creek delta) has grown twice as fast as the Athabasca River delta. Field measurements of water surface elevation show the slope of the EM channel is twice as steep as the slope of the lower Athabasca River (8 × 10 −5 vs. 4 × 10 −5 ). Because water tends to flow down the steepest slope, we expect more water to flow down the EM channel in the future. Our findings indicate a slow capture of Athabasca River water into its EM channel, with potenti...

Section: Resultsmentioning

confidence: 88%

Section: Longitudinal Discharge Measurements From Adcpmentioning

confidence: 99%

Athabasca River Avulsion Underway in the Peace‐Athabasca Delta, Canada

Wang

Smith

Gleason

et al. 2023

Self Cite

“…For example, as mentioned in Section 1, river width is one of the most important hydrologic variables for the remote sensing of river discharge. The relationships between river width and discharge, such as the at‐a‐station‐hydraulic‐geometry (AHG, w = aQ b ) (Leopold & Maddock, 1953) or at‐many‐stations‐geometry (AMHG) (Gleason & Smith, 2014), are commonly used for remote sensing of river discharge (e.g., Brinkerhoff et al., 2020; Gleason & Smith, 2014; Hagemann et al., 2017; Harlan et al., 2021; Pavelsky, 2014). GLOW will enable us to build river‐specific AHG or AMHG relationships at the global scale (e.g., Figure S9 in Supporting Information ), thus enhancing our understanding of these algorithms and improving the remote sensing of river discharge.…”

Section: Discussionmentioning

confidence: 99%

“…In hydrology, multitemporal river widths are commonly used as a proxy for river discharge based on a power law usually existing between these two variables (Leopold & Maddock, 1953). This practice serves as the basis for much recent literature on remote sensing of river discharge and hydrologic/hydraulic modeling (e.g., Brinkerhoff et al., 2020; Elmi et al., 2015; Feng et al., 2019; Gleason & Smith, 2014; Hagemann et al., 2017; Harlan et al., 2021; Ishitsuka et al., 2021; Lin et al., 2020; Mengen et al., 2020; Pavelsky, 2014). Therefore, understanding how river width changes over time is essential to both scientific and engineering applications.…”

Section: Introductionmentioning

confidence: 99%

How Have Global River Widths Changed Over Time?

Feng

Gleason

Yang

et al. 2022

Self Cite

“…These two rivers converge in the central part of the state near the village of Nenana, southwest of Fairbanks. The Tanana has been the site of several previous investigations and maps and descriptions of the study area are provided elsewhere (Altenau et al., 2017; Fulton et al., 2020; Harlan et al., 2021; Legleiter & Kinzel, 2020, 2021a, 2021c). For our purposes here, important distinctions between the two rivers include the larger size and much lower clarity of the Tanana.…”

Section: Methodsmentioning

confidence: 99%

Moving Aircraft River Velocimetry (MARV): Framework and Proof‐of‐Concept on the Tanana River

Legleiter

Kinzel

Laker

et al. 2023

Information on velocity fields in rivers is critical for designing infrastructure, modeling contaminant transport, and assessing habitat. Although non‐contact approaches to measuring flow velocity are well established, these methods assume a stationary imaging platform. This study eliminates this constraint by introducing a framework for moving aircraft river velocimetry (MARV). The workflow takes as input images acquired from an airplane and involves orthorectification, frame overlap analysis, image enhancement, particle image velocimetry (PIV), and aggregation of the resulting velocity vectors onto a prediction grid. We also use new metrics to quantify the agreement between image‐derived and field‐measured velocity vectors in terms of both orientation and magnitude. The potential of MARV was evaluated using data from two Alaskan rivers: a large, highly turbid channel and its smaller, clearer tributary. Sediment boil vortices on the mainstem provided natural features trackable via PIV and estimated velocities corresponded closely with field measurements (R2 up to 0.911). We compared an exhaustive approach that evaluates overlap for all frame combinations to a simpler rolling window implementation and found that the more efficient algorithm did not compromise accuracy. Sensitivity analysis suggested that the method was robust to window parameterization. Comparing PIV output from different flying heights and imaging systems indicated that larger pixels led to higher accuracy and that a more advanced dual‐camera system provided superior performance. Results from the tributary were less encouraging, presumably due to a lack of trackable features in visible images. Testing across a range of rivers is needed to assess the generality of MARV.