The transport and deposition of sediment is a critical and fundamental element of healthy and productive river ecosystems. Sediment deposition, however, is often a significant maintenance challenge for public works departments, because it can directly or indirectly threaten infrastructure, initiate or increase bank erosion, or raise flood risk by reducing channel capacity. For more than 20 years, there has essentially been a moratorium on removal of sediment from Pacific Northwest streams and rivers in an effort to protect and preserve sensitive aquatic habitat. During this period, the transport and deposition sediment has continued unabated with the result being that the frequency of sediment induced problems has increased.

WSE is committed to helping clients find practical and informed solutions to sediment deposition problems. The key to finding acceptable solutions is to provide stakeholders with sound scientific data to help inform their decision making processes. Our principal and senior staff’s combined 80 plus years of experience in hydrology, hydraulics, fluvial geomorphology, and sediment transport makes us exceptionally well qualified to take a lead role in this scientific effort. We are highly regarded for our ability to work collaboratively with groups of diverse stakeholders, a key trait needed when trying to find an acceptable solution to an issue that often brings out impassioned views.

Examples of our work in sediment analysis

North Fork Swift Creek Re-Route Feasibility

A deep-seated landslide in an unusual geologic formation in the Swift Creek basin produces huge volumes of sediment with potentially hazardous concentrations of asbestos and heavy metals.

Innis Creek Road Flood Mitigation Project

Innis Creek Road passes through a large wetland in which water levels rise above and typically inundate the road surface throughout the late fall, winter and spring.

Colockum Creek Bridge Scour Repair

Three Chelan County bridges sustained significant scour and erosion damage during a major flood in September 2013.

High Creek Final Design

Landslides and channel instability in High Creek produce excessive sediment that is deposited in the downstream channel reach.

Upper Hoh River Road Fish Culverts

WSE was retained to provide hydraulic engineering services for three culvert replacements along the Upper Hoh River Road in Jefferson County, Washington.

Spencer Road Bridge Blue Creek Sediment Management

Spencer Road bridge over Blue Creek in Lewis County is experiencing significant sediment deposition problems.

Manastash Creek Post Flood Investigation & Flood Relief Alternatives

In May, 2011 a major flood on Manastash Creek near Ellensburg, WA caused significant damage to private property and public infrastructure.

Monroe Street Hydroelectric Development, Spokane

Avista's Monroe Street hydroelectric project on the Spokane River in downtown Spokane is subject to excessive sediment accumulation which can plug the facility intakes causing maintenance problems and curtailing power production.

Filbert Creek Sediment Impact Investigation and Channel Redesign

Filbert Creek passes under SR-524 through a 14-foot wide, three-sided box culvert that was constructed in 2007.

Canyon Creek Sediment Management Investigation

Whatcom County retained WSE to determine if a practical and cost effective solution can be found to alleviate chronic sediment deposition problems at the Mosquito Lake Road bridge over Canyon Creek.