Construction of 176-in. and 156-in. Diameter Cast-In-Place Reinforced Concrete Siphons Expanding the East Low Canal

The Odessa Groundwater Replacement Program (OGWRP) was put in place to develop alternatives to groundwater and reduce depletion of the Odessa aquifer by delivering Columbia Basin Project surface water supply, via the East Low Canal to additional farmland. Widening of the existing canal and construction of seven additional parallel siphons was chosen as the best alternative. This paper will discuss the construction and coordination challenges that were encountered throughout the placement of (4) 176-in. and (3) 156-in. inner diameter cast-in-place reinforced concrete siphons. Lessons learned on the first contract of siphons were immediately implemented for subsequent concrete placements and contracts. Some of the more significant changes were modifications to specialized formwork and vibratory methods, creative concrete mix designs with varying slump, placement sequencing and cure time, and coordination between different entities.