Using new satellites to supplement a river monitoring program – an example from the Dolores River

Monitoring of fluvial environments is critical for measuring how rivers change in response to external and internal drivers, and for evaluating the impact of restoration programs. The Dolores River Adaptive Management and Support (DRAMS) project is a 5-year effort focused on monitoring changing conditions on the lower Dolores River, downstream of McPhee Reservoir. Building on a legacy of patchy monitoring efforts, a goal of DRAMS was to develop a consistent monitoring protocol through both dry and wet years. DRAMS monitoring occurred from 2021-2025. Monitoring efforts included the traditional pre/post comparisons (rod-and-level surveying, pebble counts, tracking mobility of designated patches of sediment, and water level loggers). We supplemented these efforts with remote sensing data leveraged from PlanetScope, a satellite constellation now collecting daily imagery at 3 meter resolution and with 4 spectral bands (R, B, G, and NIR).  

Although the river was maintained at only a small controlled release for most of the monitoring period, there was one relatively high water event (spring runoff 2023), and a handful of moderate monsoon flows. Analysis of PlanetScope imagery during that time has permitted monitoring of some channel conditions that are otherwise difficult to measure over the whole range of realistic flow levels, including: 1) Floodplain connectivity, 2) side channel length, 3) presence of pools during extreme low water conditions. These measurements allow water managers to better understand how different flow levels can impact river hydraulics, complexity, and habitat. Here I will share some of the insights gleaned from this additional monitoring perspective, and offer some considerations that prospective users should make before incorporating this approach into a protocol.