1. Chehalis Basin Rain Gauge Network
Diana R. Gergel1, Bart Nijssen1, Dennis P. Lettenmaier2
Dept of Civil and Environmental Engineering, University of Washington, Seattle, WA
Dept of Geography, University of California at Los Angeles

2. Background coastal watershed
minimally affected by snow during most precipitation events (rain-dominant) except for highest elevations (transient areas)
drains directly to the Pacific
history of intensive flooding in Chehalis Basin: flood that closed down I-5
primarily privately owned land (Weyerhaeuser)

3. 2015-2016: installation of 50-100 rain gauges
Timeline of Study
: pilot year of field study: installation of 5-10 rain gauges (dual-platform gauges); CoCoRaHS recruitment
: installation of rain gauges

5. First Year Progress
partnering with Chehalis Flood Authority for precipitation monitoring in the Chehalis
connecting dual-platform data feed to the Chehalis Flood Authority
working with WA Dept of Ecology
identifying site hosts
making contacts with local colleges (Gray’s Harbor, Centralia College)
working on gaining access to Weyerhaeuser private land
recruiting additional WA CoCoRaHS observers

6. Chehalis Flood Authority Rain Gauge Network

10. Next steps find sites at higher elevations in the Chehalis
use performance of dual-platform gauges to inform type of gauge for sitings next year
work on remote data feed so that site hosts and the Chehalis Flood Authority can benefit from precipitation data