Chelan County Public Utility District (PUD) operates the Rock Island Hydroelectric Project on the Columbia River approximately 14 miles downstream of Wenatchee, WA. The project has two powerhouses, a gated spillway, and three fish passages.

Brennan was contracted to perform concrete overlays in the draft tube of Unit B-8 in Powerhouse #1 to increase the efficiency of the hydro turbine and reduce future cavitation. At the same time, the client took advantage of this outage to perform rehabilitation and upgrades to the hydro unit and generator.

Accessing A Draft Tube 100 Feet Below the Surface

To access our work area, the Chelan County PUD installed upstream and downstream bulkheads to dewater the draft tube, removing the entire hydro turbine to assist in other planned rehabilitation. Dewatering pumps lowered the water level to approximately 3 feet, and the rest was up to us.

Identifying Spillway Failure Risks and Project Background

The Upper Baker Dam Spillway Stabilization project addressed potential failure modes in the dam’s spillway chute’s foundation, identified during a 2019 Federal Energy Regulatory Commission (FERC) Part 12D dam safety workshop. After extensive analysis, design, and consultation with FERC, the project came to fruition.

When a structural failure at the Demopolis Lock and Dam in Alabama brought barge traffic to a halt on the Tennessee-Tombigbee Waterway, the US Army Corps of Engineers (USACE), R&D Maintenance, and J.F. Brennan Company (Brennan) joined forces to deliver a fast, high-stakes solution. The breach—described by Colonel Jeremy Chapman of USACE as “a hole the size of a school bus”—stopped commercial navigation across two major waterways and threatened economic losses in the millions each month.

Refinery Wastewater Pond Cleanup with Remote Dredging

We recently completed the cleanup of two wastewater ponds for a large producer of transportation fuels. Using a remotely controlled dredge, Brennan removed wastewater sludge from impoundments on the refinery site and dewatered the material with six 2-meter belt filter presses. The remotely controlled dredge added a layer of safety to the project, preventing any health risks that a Leverman might face if exposed to hydrogen sulfide gas released during the dredging process.

Equipment-heavy industries continually push for optimal uptimes. At J.F. Brennan Company, Inc. (Brennan), we’re committed to investing in our equipment not only during the purchasing process, but also during scheduled off-season maintenance. Internally, we coined the term “Brennanize” to refer to the custom alterations our team executes upon acquiring assets as well as our carefully regimented maintenance.