Design, implementation and hydrologic evaluation of a snow-measurement network using wireless sensors in the American River basin of California

Abstract:

American River Hydrologic Observatory in the Sierra Nevada of California, comprising of portions of the American River basin that receive significant snow, is the site for the deployment of a wireless sensor network (WSN) that provides distributed estimates of water balance and a full-basin, well-instrumented research platform. The WSN is a set of sensors integrated into a single instrument to make spatial measurements to capture the landscape variability, and provide both spatially distributed and representative values of snowcover and the energy that drives snowmelt across the basin. Each local WSN has 10 snow-depth, air-temperature and relative-humidity sensors placed in a ~1-km² area, and is centered on existing snow-pillow, snow-course and meteorological-station. A subset of the nodes are equipped with 15-20 soil-moisture and soil-temperature sensors. The temporal resolution of all measurements are 15-minutes. Results indicate that the aggregate of all measurement nodes are representative of the landscape variability across the American River basin, as well as the three forks of the American River. Snow measurements across elevation gradients and at each local WSN show similar trends but different magnitudes. Across elevation gradients snow amounts can vary as much as 60%-80%, while variability across a 1-km² 10 measurement network range by as much as 60%. Additionally, spatially distributed sensors distinguish temperature and humidity differences across topographic and vegetation variables, which control variable snowmelt rates across the terrain. Snowmelt rates across a 1-km² can ranged from 8 to 70 mm day^-1. The Hydrologic data from the WSN is being used for research, and for modernizing forecasting and decision-support systems through spatially explicit modeling, and by enhancing existing physically and statistically based snowmelt and hydrologic models. Data are available through the American River Hydrologic Observatory (arho@ucmerced.edu) and real-time updates are available through SierraNet (glaser.berkeley.edu/wsn).