Upper Nisqually Channel Migration Zone Analysis
GeoEngineers responds quickly to deliver accurate flood-damage data
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The Upper Nisqually River in the rainy season
Expertise
  • River Science & Engineering

Market
  • Water & Natural Resources

Location
  • Western Washington State

Overview

In November 2006, GeoEngineers was midway through a channel migration zone (CMZ) study for Pierce County on the Upper Nisqually River when heavy storms battered the region. The storm damaged a number of bridges and caused extensive changes to the river channel. With a State deadline quickly approaching, the County had to quickly revise the CMZ study to reflect the storm damage.

Approach

To create a visual baseline for the study, GeoEngineers loaded pre-flood aerial photos into a handheld GPS unit and referenced them to GPS coordinates. GeoEngineers' channel migration specialists then flew the river by helicopter, reviewing actual conditions on the river with the pre-flood photos. The team was able to immediately provide exact GPS coordinates where large channel changes had occurred and relay this information to County planners, who used the information to plan and prioritize their efforts.

Awards


ACEC-Washington 2008 Engineering Excellence Awards, Silver Award for Innovative Application of New or Existing Techniques

Results

  • GeoEngineers provided the County with detailed information regarding the type and magnitude of channel changes within three days, allowing the client to meet the State reporting deadline, despite the dramatic channel changes.
  • By using infrared instead of standard photos, GeoEngineers was able to distinguish the difference between damaged vegetation, woody debris and the active channel to indicate flood damage accurately.
  • Through a creative arrangement with a subconsultant, GeoEngineers was able to reduce the client's orthophotography costs by two-thirds.

Accolades


From start to finish, it was clear that GeoEngineers was the right firm to hire in order to develop and complete the project.

Harold P. Smelt, Water Programs Manager
Pierce County Public Works and Utilities