LASKEY-CLIFTON CORPORATION has won a US$3.5M contract for modification work to two Oregon, US earthfill dams that will see them become more resistant to earthquakes and able to pass greater quantities of water.
Under the terms of the deal, the dams – located on Tarheel creek and Fourth creek, and together storing over 160,000m3 of water for irrigation – are to be removed and rebuilt with the aim of controlling seepage.
The news was disclosed by the Pacific Northwest office of the US Bureau of Reclamation (USBR), which is to give construction management and design support to the team.
According to the USBR announcement, engineers will add a geosynthetic material to the earthfill to protect the dams against seismic damage. ‘New fish ladders will be constructed adjacent to new spillways, which will be able to pass higher volumes of flood water,’ said USBR.
Under the Indian Dams Safety Act of 1994 (PL 103-302), the Bureau of Indian Affairs is to foot the bill.
Work is expected to begin early this year and, once completed in spring 2005, responsibility for working the dams is to pass to the Coquille tribe, added USBR.