Image analysis techniques to estimate river discharge using time-lapse cameras in remote locations

Abstract

Cameras have the potential to provide new data streams for environmental science. Improvements in image quality, power consumption and image processing algorithms mean that it is now possible to test camera-based sensing in real-world scenarios. This paper presents an 8-month trial of a camera to monitor discharge in a glacial river, in a situation where this would be difficult to achieve using methods requiring sensors in or close to the river, or human intervention during the measurement period. The results indicate diurnal changes in discharge throughout the year, the importance of subglacial winter water storage, and rapid switching from a "distributed" winter system to a "channelised" summer drainage system in May. They show that discharge changes can be measured with an accuracy that is useful for understanding the relationship between glacier dynamics and flow rates.

Automatic Image‐Based Water Stage Measurement for Long‐Term Observations in Ungauged Catchments

“…Also, water stage information can be derived from image data. Young et al () and Leduc et al () detect the waterline on stage boards or assumed vertical rocks using perpendicularly oriented cameras. Camera geometry is simplified to project waterlines from image space into object space instead of considering strict geometric modeling of surface geometry and interior and exterior camera geometry resulting in potential inaccuracies in the water stage measurement.…”

Surface melt‐driven seasonal behaviour (englacial and subglacial) from a soft‐bedded temperate glacier recorded by in situ wireless probes

“…Since there is a diurnal change (and winter diurnal rises in discharge were recorded (Young et al, 2015), these sources must be a combination of the release of storage (Rennermalm et al, 2013;Schoof et al, 2014), as well as melt generated from glacier movement. It could be argued that the melt season water pressure stability was because the borehole remained full of water (from the drilling) and was unable to drain (DOY 220-291).…”

“…But once surface inputs were stopped, during winter, water pressure decreased and the only water sources must be within the ice. Since there is a diurnal change (and winter diurnal rises in discharge were recorded (Young et al, 2015), these sources must be a combination of the release of storage (Rennermalm et al, 2013;Schoof et al, 2014), as well as melt generated from glacier movement. This 'new' water has much lower conductivity (due to dilution) and higher temperatures.…”

Technical Note: Semi-automated effective width extraction from time-lapse RGB imagery of a remote, braided Greenlandic river

“…Another parameter estimation approach relies on water surface delineation from automatically generated DEMs constructed from stereo imagery and other data sources (Chandler et al, 2002;Ashmore and Sauks, 2006;Bird et al, 2010;Bertoldi et al, 2010). Additionally, Young et al (2015) recently demonstrated the effectiveness of calculating water stage change at a station from terrestrial photogrammetry, which they combined with assumptions of channel geometry and roughness to calculate river discharge via Manning's equation. This approach is highly effective, but limited to situations where bathymetry is known or channel geometry may be simply described.…”

“…Braided rivers in particular typically display a power-law relationship between floodplain inundation area (which can be remotely sensed) and discharge, which has been exploited using satellites, aerial imagery, and terrestrial time-lapse photography (Smith et al, 1996;Smith, 1997;Chandler et al, 2002;Ashmore and Sauks, 2006;Egozi and Ashmore, 2008;Smith and Pavelsky, 2008;Bertoldi et al, 2009;Hundey and Ashmore, 2009;Bertoldi et al, 2010;Bird et al, 2010;Ashmore et al, 2011;Welber et al, 2012;Williams et al, 2013;Young et al, 2015).…”