SEQUIM — An off-stream reservoir is under consideration to solve two problems: flooding from heavy rains and the needs of irrigators when the Dungeness River is low.
Last year, a zero snowpack in the Olympics led to drought conditions, with such low flow in the Dungeness River that Sequim-Dungeness Valley irrigators cut back to minimize diversion from the waterway.
Yet the dry summer was followed by a rainy fall, which put a strain on the drainage system for the city of Sequim, leading to flooding in some areas.
The situation led to local and state water managers and stakeholders pursuing an off-stream reservoir.
They are eyeing a site, owned by the state Department of Natural Resources, off River Road.
Preliminary planning is underway. The reservoir could range from 32 acres to 88 acres, with storage capacities from 550 acre-feet to 1,586 acre-feet.
“To me, the significance of that is, it’s enough water to avoid diverting Dungeness River water for more than a month,” said Ann Soule, city of Sequim water resource specialist.
The concept of a reservoir would be to divert early summer snowmelt from the nearby Dungeness River via existing irrigation canals, as well as capture stormwater runoff.
The onset of precipitation late in 2015 recharged the flow of the Dungeness River, which had dropped throughout the summer given the lack of snowmelt and the diversion of water from its channel by Sequim-Dungeness Valley irrigators from April 15 to Sept. 15.
Although the rainfall brought relief from the drought, it also put strain on the drainage system for the city of Sequim.
After and during storms, water runoff from the western Happy Valley area and Burnt Hill flowed toward the city, entering a maze of irrigation ditches, pipes and canals, including Bell Creek.
“It really becomes a problem because so much of the runoff does eventually end up in Bell Creek, and Bell Creek can just not handle it,” said David Garlington, city public works director.
“It [Bell Creek] traverses the entire city from the southwest corner to the northeast corner, so there are multiple opportunities for it to be a headache for the city and residents of the city.”
Areas with high water tables, such as Falcon Road southwest of Sequim, “can’t take on too much more water after we’ve had enough rain in the fall,” Soule said.
“Every time a house goes up on Burnt Hill probably exacerbates this because there’s such a slope, and impervious surfaces combined with slopes just generates tons of water,” she said.
“I think the amount of water is only going to go up coming from development on Burnt Hill.”
Already, flooding occurs throughout the city when the drainage system reaches its capacity, Soule said, pointing to Carrie Blake Park as an example.
Beyond providing a water supply for irrigators, reducing stormwater stress on the city of Sequim, the proposed reservoir could benefit fish and wildlife and provide recreational and infiltration opportunities, say supporters of the idea.
“We received a letter back from DNR indicating they were supportive of the concept,” said Amanda Cronin, Washington Water Trust project manager.
DNR officials also indicated interest in doing a land exchange for timberland of comparable value, Garlington said.
Early project cost estimates range from $20 million to $40 million.
Engineers with environmental consulting firm Anchor QEA of Seattle are developing a proposal for a reservoir, Cronin said.
Partners in the proposed project include officials with the Clallam Conservation District; Washington Water Trust; the state departments of Ecology, Natural Resources and Fish and Wildlife; the Jamestown S’Klallam tribe; the Dungeness Water Users Association; Clallam County; and the city of Sequim.
However, given the scope and costs of the project, Cronin predicts a long road ahead, with no set timeline just yet.
“I do think the unprecedented drought is a catalyst for driving new ideas like this,” she said.
“2015 gave us a look at what conditions could look like in the future with climate change.”
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Information is from Alana Linderroth, a reporter with the Olympic Peninsula News Group, which is composed of Sound Publishing newspapers Peninsula Daily News, Sequim Gazette and Forks Forum. Reach her at alinderroth@sequimgazette.com.
