New gages are being added near the Nooksack River to provide faster warnings when water has surged over dikes near Everson and Nooksack, and to give scientists more precise data on where floodwaters are flowing in rural areas of northern Whatcom County.
One gage will measure stream flow and depth in real time for the U.S. Geological Survey and the other is a water sensor to let USGS and Whatcom County officials know when water is flowing over Emerson Road south of Everson, a sign that floodwaters are heading toward downtown Everson and Nooksack, said John Thompson, a senior planner in the Natural Resources Division of the Whatcom County Public Works Department.
"That's the road that overtops when the flow to Sumas initiates," Thompson told The Bellingham Herald.
A pair of torrential rainstorms in mid- and late November 2021 caused floods in Whatcom County that killed one person and caused more than $150 million in damages.
"Once that road overtops, it's flowing across the field. It has kind of a warning system component," Thompson said.
A camera will be added at that location so that Public Works won't have to station a person to watch the river.
"We won't have to put someone physically out there when they could be elsewhere," he said.
A second new gage is being placed seasonally in the Sumas River, but the location hasn't been chosen yet, Thompson said.
"It helps us better understand the November 2021 flood and it helps us better understand future flood events, too," he said.
About 20 gages are installed along the Nooksack River system, including the north, south and middle forks and the river's main channel as it widens west of Nugents Corner, said John Greene, field office chief at the USGS's Northwest Washington office in Ferndale.
Those gages send data via satellite that is used by a host of agencies, including Whatcom County, the USGS, and NOAA's Northwest River Forecast Center, which predicts if flooding can be expected based on rainfall forecasts from the National Weather Service and historical river measurements.
"It's such a dynamic system. It's nearly impossible to get your finger on the pulse of what's going on," Greene told The Herald.
Warm winter storms called "atmospheric rivers" occasionally drop immense amounts of rain in a short time, causing rapid snowmelt in the mountains and sending torrents of water downstream, along with sand and gravel.
That gravel builds up south of Everson and Nooksack and causes water to spill out of its channel, like a huge clogged drain pipe, Greene said.
A slug of gravel built up after the first November 2021 flood and then a second lesser storm at the end of the month also caused flooding that caught officials by surprise, he said.
"That's what we're hoping, is that these river gages will give people some advance warning," Greene said.
