Description

Thomas/Wright, Inc. performed the high accuracy deformation monitoring surveys for the U.S. Army Corps of Engineers, Portland District.

The project scope was to perform deformation monitoring of the John Day Dam and Lock, Detroit Dam, Big Cliff Dam, Hills Creek Dam, and Lookout Point Dam located in the State of Oregon.

Previous years included the Applegate Dam, Cougar Dam, and Lost Creek Dam.

Before mobilization of the field crew, T/WI conducted an inspection tour of the dams to identify potential maintenance issues, especially line-of-site problems, condition of control monuments, and coordinated with the on-site Project staff, where required. An inspection report with recommendations was prepared.

The monitoring involved collecting field data as outlined in the procedures provided by the Corps for each dam. The horizontal monitoring included standard dam check trilateration, radiation measurements, and standard alignment procedures. The vertical monitoring included 2nd Order Class I and 3rd Order leveling procedures.

The distance measurements and angles were conducted using a Wild T2002/DI2000 instrument reading to 0.1 second in angle and 0.0001 meters in distance. Level runs and loops were conducted with a Leica DNA10 digital level reading to 0.001 feet in elevation.

The survey data, field notes, prism calibration files, work reports, and other pertinent materials were delivered to the Corps.