Bothell’s Horse Creek will again see the light-of-day

For more than 50 years, Horse Creek through Bothell has been diverted into an underground culvert before emptying into the Sammamish River. As part of Bothell’s downtown revitalization plan, the section of Horse Creek running through Bothell’s downtown core will be moved and re-exposed. This process is called day-lighting.

The city of Bothell is amid a multi-phase redevelopment of its downtown area that includes $207 million in private investments and $150 million in public expenditure. The overall project involved the moving of State Route 522 one block south, while extending Main Street one block west to the library. Some of the new development will occur on top of where the existing pipe runs carrying Horse Creek.

The goal of the new development is to attract more people to live, shop and dine in downtown Bothell. The day-lighting of Horse Creek will not only attract people, but soon salmon may be seen swimming through the downtown core.

According to the city’s plans, the newly day-lighted Horse Creek will be moved above ground at NE 188th Street and remain above ground until it empties into the Sammamish River at the west end of Bothell Landing Park, south of SR-522. Segments where the creek passes under driveways and intersections will be outfitted with fish passable culverts. Once the creek enters the park at Bothell Landing, the vegetative buffer surrounding the creek will be extended beyond the walls of the stream channel.

Along the entire stretch of the soon-to-be exposed Horse Creek, city planners expect pedestrians will soon enjoy the aesthetics of the stream. Within the channel, project engineers plan to plant a mix of native plants.

The pipe within which Horse Creek currently flows has had capacity issues and portions have condition problems, said Steve Morikawa of the city of Bothell.

“Portions of the new downtown development will be built on top of where the existing pipe runs,” he said. Adding, the location of the new development will prevent the city from maintaining the existing pipes.

Thus, city staff decided moving the pipe was necessary.

Before being channelized and redirected underground, Horse Creek was utilized by salmon returning from the Puget Sound to spawn. Today, anytime someone wants to move a creek, it must attain approval from multiple government agencies as well as receive consent from local tribes.

Thus, the creek must appease the interests of the native tribes. Treaties between tribes and the federal government require that streams are fish passable. In a letter to the city of Bothell, Karen Walter, watersheds and land use team leader for the Muckleshoot Indian Tribe’s fisheries division, wrote, “we support all efforts necessary to daylight piped streams to increase habitat for salmon.” adding, “we encourage the City to develop a stream channel and riparian area to the fullest extent possible in this Horse Creek corridor.”

The new stream will be fish passable, though there is no guarantee we will see fish in Horse Creek. However, at least one of the city’s environmental landscape advisers is optimistic salmon will return to Horse Creek. Peggy Gaynor, of Gaynor Inc., in an email response about this story wrote, “From our experience, salmon are opportunistic so that even in urban creeks some amount of rearing and refuge occur.”

Due to the urban nature of Horse Creek, the City of Bothell staff asked the city council to amend the existing city code to allow for a narrower buffer around the proposed day-lighted creek. The existing code typically requires a 75-foot buffer on each side of the creek. The amended buffer for Horse Creek within the downtown will be within the wall of the new creek channel. Without this reduced buffer too much land would be taken from the property, making it unlikely for a developer to build on the available lots. Moreover, if too much land is taken away from potential redevelopment, there would be less development, development which is funding a portion of the stream project.

The estimated cost of the day-lighting is $13.6 million, according to the City of Bothell’s city council agenda bill summary from 2012. Most of the cost of the project will be paid through rate-payer increases, but a substantial portion of the cost will be paid by the developers of the new downtown projects. The city’s new direct discharge system, also part of the revitalization will enable developers to maximize the use of their parcel while potentially saving money because the developers will not be required to install onsite storm water detention.

The project is scheduled to begin this spring, and it is projected to be completed by March 2016.

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