GRI Gcolcchnical & Environmental Consultants

9725S\\'Beave[ion-Hi]]sda1eHv.y, Ste 140 Portland, Oregon 97005-3364

PHONE 503-641-3178 FAX 5 03-64 4-80 34

January 5, 2004

Portland Development Commission

1900 SW Fourth Avenue, Suite 7000

Portland, OR 97201-5304

3990 GEOTECHNICAL RPT

(ISSUED 2/^2004)

DRAFT

Attention:

SUBJECT:

Bob Van Vickie

Preliminary Geotechnical Investigation and General Geotechnical Considerations

CSO Easement and Tunnel

South Waterfront Lot #3, Work Order No.: 201282-10 (Amendment #1)

SW Moody Avenue and SW River Parkway

Portland, Oregon

At your request, GRI has conducted a preliminary geotechnical investigation for the above-referenced

property. The parcel is located in the southwest quadrant of the intersection of SW Moody Avenue and SW

River Parkway in the South Waterfront Urban Renewal District. The general location of the site is shown on

the Vicinity Map, Figure 1. We understand PDC is granting a sliver-shaped easement for the CSO Tunnel

project along the SW River Parkway frontage of the property. Parcel 3 and the easement are shown on the

Site Plan, Figure 2. The purpose of this investigation is to review the existing geolechnical information for

the area, perform two subsurface exploration borings on and near the easement prior to tunnel construction,

provide general preliminary geotechnical recommendations concerning future development, and comment

on potential restrictions for future pile foundations that may installed in close proximity to the tunnel. This

report documents the work accomplished and provides our conclusion and recommendations. Our report

was completed after review of comments by PDC and Grummel Engineering.

Available geotechnical information developed for the area by GRI is summarized in the following reports:

"Results of Exploration Borings, Parcel 3 Waterfront Improvements for the Portland

Development Commission (PDC), Portland, Oregon," dated August 1987

Preliminary Geotechnical Investigation, Proposed Pacific Power & Light Company

Substation Relocation, South Waterfront Area, Portland, Oregon," dated August 1987

"Final Geotechnical Report, South Waterfront Improvements for the Portland

Development Commission (PDC), Portland, Oregon," dated November 1988

"Geotechnical Investigation, 5outh Waterfront Park Project, Portland, Oregon," dated

February 1998

In addition, we also reviewed the logs of borings drilled in the area by Parsons Brinckemoff for the CSO

project, which were forwarded to us by PDC from the City of Portland Environmental Services. These