Cornforth Consultants
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Cowlitz River Levee Investigation

Longview, Washington
Cornforth Consultants was retained by the Portland District, US Army Corps of Engineers to perform geotechnical field explorations and laboratory investigations and prepare a Geotechnical Data Report for five Cowlitz River levees. The investigations were conducted to determine existing levee foundation conditions and embankment properties for future stability analyses on the Castle Rock, Longview, Coweeman, Kelso, and the Lexington Levees.
​
The work consisted of drilling and sampling, Standard Penetration Tests (SPT), Cone Penetrometer Tests (CPT), laboratory testing to develop material properties, and falling head tests in the field to determine in-situ permeability. The program consisted of 14 borings and 17 CPT probes. SPT’s and falling head tests were conducted in each borehole. The CPT data was processed and interpreted to establish correlations with soil behavior classification, angle of internal friction, and equivalent SPT, N60 values. Friction angle strengths were also obtained by correlating blowcount data obtained from SPT tests.

 

Scaling 250 feet above Highway 2 and BNSF Railroad
CPT Explorations on the Coweeman Levee

​Services Provided:

  • Geotechnical Instrumentation
  • Hydrogeology
  • Laboratory Testing
  • Levee Safety Evaluation
  • Embankment Stability Analysis
  • Field Explorations
  • Home
  • Services
    • Earth & Rockfill Dams
    • Reservoirs, Canals, and Levees
    • Spillway Safety Inspections
    • Landslides and Rockfall
    • Earthquake Engineering
    • Geologic Hazards
    • Geotechnical Site Characterization
    • Hydrogeology
    • Expert Witness
    • Concrete Dams and Locks
    • Geotechnical Instrumentation
    • Deep and Shallow Foundations
    • Geotechnical Manuals
  • Industries
    • Water Resources
    • Energy
    • Natural Resources
    • Industrial
    • Transportation
    • Ports and Airports
    • Expert Witness
  • Projects
    • Earth and Rockfill Dams >
      • Barney Reservoir
      • Frog Lake Reservoir
      • Iron Gate Dam Raise
      • McGuire Dam Raise
      • Bonneville Cofferdam
      • Bull Run No. 2 Seismic Stability Analysis
    • Levees and Canals >
      • Libby Dike Rehab.
      • St. Johns Dike Stabilization
      • Cowlitz River Levees
      • Swift Canal Failure
    • Earthquake Engineering >
      • Barney Dam Seismic Analysis
      • Fern Hill WTP Liquefacation Study
      • Bull Run No. 2 Seismic Stability Analysis
      • Mt. Tabor Seismic Stability Analysis
      • Port Westward Power Plant Seismic Design
    • Rock Slopes and Tunnels >
      • Libby Rockfall Mitigation
      • Sandy River Pipeline Tunnels
      • Ketchikan Third Avenue Extension
      • Sain Creek Water Supply Tunnel
      • Montana Rockfall Hazard Rating System
    • Foundations >
      • Port Westward Power Plant
      • Cascade Locks Casino
      • Air National Guard Hangar
      • Biglow Canyon Windfarm
      • Oakridge Water System Improvements
    • Concrete Dams and Locks >
      • John Day Lock & Dam
      • Marmot Dam Removal
      • The Dalles Dam
      • Willamette Falls Dam
      • Bonneville Dam
    • Transportation >
      • OTIA Cracked Bridge Geotechnical Baselines
      • Newburg Dundee Bypass Design DEIS
      • I-84 Sandy River Bridge Investigation
      • Tanana River Bridge Foundation, Tok, Alaska
      • Montana RHRS Implementation
      • Ketchikan Third Avenue Extension
    • Ports and Airports >
      • Navy CVN Drydock
      • Depoe Bay Seawall Distress
      • Willamette Falls Flow Control Structure
      • Air National Guard Hangar
    • Water and Wastewater >
      • Fern Hill Water Treatment Plant
      • Tualatin Valley North Transmission Line
      • Evaluation of 28 Water Storage Facilities
      • City of Sandy Water Treatment Plant
      • Mt. Tabor Reservoir No. 5 Cap Study
      • Oakridge Water System Improvements
  • Staff
  • Resources
  • Careers
    • Geotechnical Engineer
  • Contact Us