Flooding is a natural part of life in the lower Snoqualmie Valley area of Western Washington. Historically, when seasonal rains would begin, many residents, land managers, and farmers would use as many data resources as they could to know if and when the Snoqualmie River would leave the banks and cover roads and farm fields. They need to prepare ahead of time by moving equipment and livestock to high ground.

Originally, there was only one US Geological Survey gauge transmitting water level data during a flooding event along the 30 miles of the river. However, community members in this area knew of multiple places where water would spill out from the banks of the river.

We have a lot of caring, clever, ambitious people in the valley. Around 2018, this project was coordinated to monitor water levels better near these roads. Community members set out to survey road levels, engineer ultrasonic sensing devices, build gauge structures, and program a LoRaWAN radio network. Snoqualmie Valley Preservation Alliance, in coordination with Geary Eppley and with funding from a King County Flood Control District grant, began creating a flood-monitoring network to enhance visibility of flooding up and down the river.

This picture (above left) is the type of scenario that many residents and land managers were encountering. They didn’t know how deep the water was, if it was rising or falling, and if there was even water at all along a road if they lived offsite from where they worked and needed to commute in.

The solution (above right) was to create a monitoring system that detected water height at different levels: Dry, Normal, Near Flooding, and Flooding. All relative to the nearby roads.

Today, we have expanded the network to cover 14 unique flood-prone sites to monitor those water levels. They transmit data every 15 minutes, 24 hours a day. We also import USGS gauge data to this map as well. Our Forecast page brings in flooding prediction data upstream.

This data can be found on the Floodzilla website or in our phone app, where you can sign up for specific site-flooding and flood-prediction alerts via text or push notifications. The Floodzilla Gauge Network is free for the public to use.

Regina Fletcher is the Floodzilla Gauge Network Program Manager at the Snoqualmie Valley Preservation Alliance, a community-based, 501(c)(3) nonprofit organization committed to protecting and enhancing the lives, livelihoods, lands, and waters of the beautiful Snoqualmie River Valley.