Simply Brilliant! New Approach for Isolating Spillway Gates

The eight spillway gates at Brilliant Dam had never been dewatered since the dam’s construction during World War II and were in need of painting and maintenance. A spillway gate isolation system was not incorporated into the structure for the 34-feet-wide by 36-ft high vertical lift roller gates when the dam was constructed. Lowering the reservoir was also not an option for this run-of-river hydro plant on the Kootenay River. As the operating agent for Brilliant Dam, FortisBC selected a design-build team of Dix Corporation, Aubian Engineering, Schnabel Engineering and Northwest Steel-Fab for provision of a means to isolate an individual spillway gate. They proposed a reverse needle cofferdam using “floating needles” – an industry first. The floating needle design utilized Aubian Engineering’s patented system for segmental floating stop logs. This spillway gate isolation system was successfully installed in an individual bay at Brilliant Dam in late March 2008, just before the spring freshet was to begin. With the spillway bay dewatered, FortisBC began rehabilitation and repainting of the now dry and accessible gate. 14 pp, 6 references.