New technique helps tribe explore groundwater-fed creeks

Squaxin Island Tribe biologists are using an underwater camera to find juvenile salmon in small creeks. The camera is paired with a cell phone to peek into pools and underneath logs.

The technology is complementing snorkel surveys the tribe is conducting throughout the Skookum Creek watershed to determine where juvenile coho rear.

The camera can get into some tributaries, like Little Creek, that are too small for snorkelers to access. The biologists can look at the snapshots to see if the fish are showing signs of stress.

Surveys have shown that coho prefer cool refuges fed by groundwater. “No matter how good the habitat was otherwise, if the water was too warm, the fish weren’t there,” said Sarah Zaniewski, a tribal salmon biologist.

“These small tributaries are important places for coho salmon and largely depend on vulnerable supplies of groundwater to make them accessible to fish,” said Erica Marbet, the tribe’s hydrologist.

Because coho don’t immediately leave fresh water in the spring like other salmon, they are more susceptible to the impacts of summer low flows.

During summer low flows the only water getting into Little Creek is groundwater. “We can tell because the water here is so cold, right around 55 degrees, and there isn’t any rainwater in the stream right now,” Marbet said. Groundwater is the temperature of the earth, which is colder than surface water warmed by the sun. “If we didn’t have groundwater here, this stream would be dry,” she said.

In addition to being available year-round, groundwater is resilient to temperature changes during the day. “Elevated stream temperatures can be lethal to salmon,” Zaniewski said. “Elevated water temperatures can cause undue stress and affect feeding and growth patterns, which can lead to premature mortality.”

Groundwater is an important consideration for salmon because of the proliferation of permit-exempt wells in the Squaxin Island Tribe’s treaty-protected fishing area. According to the State of Our Watersheds Report produced by the treaty tribes in western Washington, more than 250 new permit-exempt wells have been drilled since 2010 in the watersheds around Skookum Creek.

A study on nearby Johns Creek estimates that more than 50 percent of the water withdrawals there are from permit-exempt wells.

“These wells come online without anyone really knowing what impact they’re going to have or what water resources are even available,” said Andy Whitener, natural resources director for the tribe. “We know salmon need groundwater, especially coho. At the very least, we need better monitoring and research on water withdrawals so we can protect salmon.”