A tunneling project to control river temperatures for fish on the Sultan River is approaching completion by the Snohomish County Public Utility District (PUD). The goal is to have the Jackson Hydro Project finished when salmon return to spawn this fall.
"We just had opportunities to create options for the fish," says Keith Binkley, the PUD’s natural resources manager.
This portion is called the Water Temperature Conditioning Project (WTC). It is the second phase of changes that came with the re-licensing of the hydro project. The first phase opened in late 2016: the breaching of a diversion dam six miles below the main Culmback Dam that created Spada Lake, which supplies Everett’s drinking water.
Binkley says when the diversion dam was altered to allow fish passage, they started populating much of the six miles leading to the main dam. That stretch of the river did not allow for the passage of salmon even before the Culmback Dam was built, Binkley noted.
He says different times require different temperatures for returning salmon. The expectation is that salmon will create nests, called redds, where they will lay their eggs about two miles below the larger Culmback Dam. Temperatures can be modified to help rear younger fish when they hatch.
An existing pipe can bring warmer water from the upper part of the lake, which measured at 73 degrees on this day. But the lake, which is 225-feet deep, reaches all different temperatures, sometimes down to 40 degrees.
The WTC project creates a new 700-foot tunnel that diverts some of the cooler, deeper water into the Sultan River. A valve system can pull water from different depths depending on what temperature is needed, and even mix it with the warmer water from the existing pipe.
The cost of the Jackson Hydro Project is $7.5 million.
