Technical note: Stage and water width measurement of a mountain stream using a simple time-lapse camera

Abstract

Abstract. Remote sensing applied to river monitoring adds complementary information useful for understanding the system behaviour. In this paper, we present a method for visual stage gauging and water surface width measurement using a ground-based time-lapse camera and a fully automatic image analysis algorithm for flow monitoring at a river cross section of a steep, bouldery channel. The remote stage measurement was coupled with a water level logger (pressure transducer) on site and shows that the image-based method gives a reliable estimate of the water height variation and daily flow record when validated against the pressure transducer (R = 0.91). From the remotely sensed pictures, we also extracted the water width and show that it is possible to correlate water surface width and stage. The images also provide valuable ancillary information for interpreting and understanding flow hydraulics and site weather conditions. This image-based gauging method is a reliable, informative and inexpensive alternative or adjunct to conventional stage measurement especially for remote sites.

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

“…The approach shown in this study either requires river segments with distinct changes during an image sequence, for example, due to waves, or opaque water in the case of calm conditions to avoid edge detection of underwater structures. Therefore, turbulent rivers, like those captured by Young et al (), Gleason et al (), and Leduc et al (), and/or sediment loaded rivers would be suitable locations.…”

“…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.…”

A rockfall-induced glacial lake outburst flood, Upper Barun Valley, Nepal

“…The mass entry rate of the avalanche into the lake was adapted from Lala et al (2018), which simulated potential avalanches and resulting impulse wave-induced GLOFs at the nearby Imja Tsho. Because Langmale glacial lake was mostly filled to its previous water level with debris, it was assumed that 1.1 million m 3 entered the lake, and the inflow of avalanche mass from Imja Tsho was scaled linearly such that its total volume was equal to this number.…”

“…The use of two distributions also provided some quantification of uncertainty associated with the erosion due to the grain size distributions. Density and porosity were determined from a sample taken at Imja Tsho (Lala et al 2018), yielding values of 1800 kg m −3 and 30%, respectively.…”

Spatiotemporal Variability in Water Sources Controls Chemical and Physical Properties of a Semi‐arid Urban River System

“…These processes differentially affect water sources contributing to river discharge (Kendall et al 1995;Kendall and Caldwell 1998). Analyses of water isotopes have been used in urban watersheds to quantify changes in stormwater discharge resulting from altered stormwater management (Jefferson et al 2015), to investigate variation in municipal water sources Jameel et al 2016Jameel et al , 2018Tipple et al 2017), and to show evidence of interbasin water transfers (Good et al 2014).…”