Project Details

Owner: U.S. Department of the Interior, Bureau of Reclamation

Contract value: $17,276,691

Description

The Glenn-Colusa Irrigation District (GCID) Hamilton City pump station is located approximately 100 miles north of Sacramento. Because GCID was one of the largest diverters of Sacramento River water, its pumping operations were identified as a significant impediment to downstream migration of juvenile salmon.

The new fish screen extension structure was over 600 ft long and when combined with the existing fish screen was over 1,200 ft long. The combined fish screen structure was the largest in the world at the time of construction. Another feature of this project was the water control structure. This structure used a series of removable weir blocks to raise or lower the water elevation in the fish screen area to control flow.

Other modifications to the diversion facility included access and temporary roads, a 54-in MLMC steel pipe bypass line (approximately 1,700 linear ft of it underwater), and a bridge. Shimmick installed and dewatered temporary cofferdams in the river and installed a 60-in RCP bypass pipeline, and excavated about 50,000 cubic yards of soil in this environmentally sensitive area.