USACE Walla Walla District IDIQ

LOCATION:  Washington   |   OWNER:  USACE Walla Walla District
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The U.S. Army Corps of Engineers (USACE), Walla Walla District, awarded a five year Architect-Engineer (A-E) Indefinite Delivery/Indefinite Quantity (IDIQ) contract to McMillen Jacobs. Under this contract, individual task orders specify the professional services procured, including electrical, mechanical, structural, hydraulic, geotechnical, and civil engineering as well as the preparation of plans and specifications and/or other engineering documents and reports. Example task orders included:

McNary Lock and Dam, Potable Water System (PWDS). McMillen Jacobs provided plans and specification for the PWDS upgrade. The McMillen Jacobs team performed all hydraulic, structural, mechanical, electrical, geotechnical, and civil engineering necessary to produce the design package. The new distribution system was hydraulically modeled to determine appropriate size of the new yard and distribution piping. Facilities requiring potable water included the McNary Lock and Dam powerhouse, two machine-shop and warehouse buildings, a yard fire suppression system, and two outdoor park restrooms. A new 520,000-gallon, cast-in-place concrete reservoir has been designed to provide both the fire-flow volumes needed for the project as well as a normal 17-hour, uninterrupted water supply to the powerhouse and turbines. The system provides up to 1.0 million gallons per day (MGD) of clean utility water to the dam powerhouse for lubrication and seal water to all 14 of the powerhouse hydropower turbines.

McNary Lock and Dam, Top Spillway Weirs Permanence. To explore new fish passage technologies, Top Spillway Weirs (TSWs) were designed and prototype tested at McNary Lock and Dam on the Columbia River beginning in 2008. The TSWs were initially developed to gather fish passage information prior to implementing major retrofits, were portable, and consisted of two different configurations. The fish passage benefits provided by these structures created the requirement to make the TSWs permanent, which required additional work. McMillen prepared plans and specifications of two new hoist stands for raising the spillway gate, installation of two new easy-to-remove sealing structures attached to the bottom of the upper gate leaf, and repair of a previously modified concrete parapet to provide adequate fall protection for McNary staff and visitors.

Ice Harbor Lock and Dam, Downstream Navigation Lock Gate Machinery Replacement. McMillen Jacobs designed the replacement/upgrade of the navigation lock downstream lift gate hoist machinery and associated electrical and control equipment at Ice Harbor Dam. Mechanical upgrades for the project included the replacement of the gate hoist gear boxes, brakes, repair or replacement of the friction sheave ring gear and pinion spur gear, corresponding pinion shafting and bearings, sheave bearings, and replacement of the hydraulic motors with electric, Variable Frequency Drive (VFD) controlled motors. The scope also includes replacing the equipment hoist with a 4 ton, 2-speed electric hoist with single speed motor controls on the bridge and trolley axes. Electrical upgrades for the project include replacement of motor control centers, installation of new motors, VFD motor starters and controls, and control modifications to incorporate a modern PLC control system. The building and roof will also require extensive upgrades to meet current standards.

Dworshak Dam, Regulating Outlet Upgrade. Dworshak Dam spans the north fork of the Clearwater River, approximately 44 miles east of Lewiston, Idaho, near the town of Orofino, Idaho. Dworshak Project (dam and powerhouse), completed in 1973, serves many functions including flood control, river water level maintenance, recreation, and power generation. Three regulating outlet intakes (RO) were placed in the dam during original construction. McMillen Jacobs designed the upgrade of all three RO’s. The upstream intake openings are 22 ft tall by 16 ft wide at the face of the dam. These bell mouth intakes taper, once inside the dam, to approximately 12.5 ft tall by 9 ft wide at the Tainter gate valve (approximately 30 ft inside the dam). Depending upon forebay elevation and Tainter gate opening, discharges through each RO can exceed 10,000 cfs. Operation of the RO depends upon downstream water needs and the quantity of flow entering Dworshak Reservoir. The ROs are necessary during certain periods of the year when the forebay water surface is below the spillway crest and outflows required from the dam surpass powerhouse capacity. The RO needs to be operational to make storage space available for incoming water during the spring runoff season, and during the early summer months the ROs regulate the downstream water temperature.