Pipeline maintenance leads to stream restoration

Staff Reports

While conducting maintenance on our Northwest Pipeline in Washington in 2017, Williams had the opportunity to participate in a restoration project for a tributary of Walter Creek. Today, water flows and fish swim in what used to be a barren creek bed.

The Walker Creek Tributary Stream Restoration Project in Skagit County, Washington repaired a section of exposed natural gas pipeline and restored the instream habitat in a tributary channel to Walker Creek. The pipeline crossed the tributary approximately 200 feet from Walker Creek which supports several species of fish including Cutthroat Trout and Chinook Salmon.

The stream restoration along the tributary to Walker Creek removed the barrier to fish passage caused by the exposed pipe and the fluctuation of the stream bed. The restoration returned the streambed to a normal level and allowed the pipe to remain permanently covered by streambed material.

In addition, we removed non-native invasive plant along the creek banks and re-planted a native riparian buffer of shrub vegetation. This work is near an existing riparian enhancement project along the banks of Walker Creek and was designed to complement the restoration work already being done.

Williams’ engineers along with experts from Golder Associates created a design that brought the channel back to a level consistent with the adjacent upstream channel, stabilized the banks, improved the vegetation along the banks.

This project is an example of how Williams designs projects to not only resolve pipeline maintenance concerns but also to incorporate environmentally beneficial elements.

In the case of Walker Creek Tributary, we saw an opportunity to add to an existing effort to improve the riparian and aquatic habit along Walker Creek by incorporating stream habitat restoration principals into the Walker Tributary pipeline repair.

Before restoration work:

After restoration work: