Articles | Volume 22, issue 1
Technical note
03 Jan 2018
Technical note |  | 03 Jan 2018

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

Pauline Leduc, Peter Ashmore, and Darren Sjogren

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.

Short summary
We show the utility of ground-based time-lapse cameras for automated monitoring of stream stage and flow characteristics. High-frequency flow stage, water surface width and other information on the state of flow can be acquired for extended time periods with simple local calibration using a low-cost time-lapse camera and a few simple field measurements for calibration and for automated image selection and sorting. The approach is a useful substitute or complement to the conventional stage data.