Low-cost stage-camera system for continuous water-level monitoring in ephemeral streams

Monitoring ephemeral and intermittent streams is a major challenge in hydrology. On-site inspections may be impractical in difficult-to-access environments. Motivated by the latest advancements in digital cameras and computer vision techniques, in this work, we describe the development and application of a stage-camera system to monitor the water level in ungauged headwater streams. The system encompasses a consumer-grade wildlife camera with near-infrared (NIR) night vision capabilities and a white pole that serves as reference object in the collected images. The feasibility of the approach is demonstrated through a set of benchmark experiments performed in natural settings. Maximum mean absolute errors between stage-camera and reference data are approximately equal to 2 cm in the worst scenario that corresponds to severe storms with intense rainfall and fog. Our preliminary results are encouraging and support the scalability of the stage-camera in future implementations in a wide range of natural settings.