The South Columbia Basin Irrigation District planned to install concrete lining on the 1,800 cubic feet per second Potholes East Canal from Station 1946+50 to 1958+50. The existing compacted earth lining seemed to be deteriorating and had been repaired several times, with additional core banking installed in 2008. Despite the core banking, the canal continued developing minor sinkholes and the district wished to reduce the risk that future sinkholes could lead to a major canal failure. The work required lining approximately 1,200 feet of the earthen canal with a 4-inch shotcrete liner and geomembrane liner.
Three design alternatives were presented during the bidding period, allowing the district to determine which alternative best fit its long-term goals, operationally and financially. The design alternatives included: 1) pneumatically placed, fiber reinforced finished shotcrete; 2) geosynthetic membrane liner with a shotcrete finish; and 3) conventionally placed, unreinforced, finished concrete.
RH2 produced the specifications and design drawings for the lining project and provided services during bidding and construction.