Bitter Root Irrigation District Siphon

The siphon and bridge both presented serious problems including structural integrity and leaking that would eventually fail. After careful inspection, Morrison-Maierle found deterioration in all areas including the pipe, expansion joints, shallow pier footings, and bridge trusses. Investigations indicated that the bridge footings lacked sufficient depth, and as the river migrated, the entire bridge would eventually collapse.

Failure of any major element of this project would result in a total loss of irrigation water to the Bitterroot Valley and would eventually cause damage to the river system, wetlands, residential homes, and the adjacent U.S. highway as all are impacted by the water provided by the BRID. As with most water projects, economic impacts on the area’s agriculture, economy, and recreation would be felt if any part of this infrastructure failed.

Morrison-Maierle came up with a solution that simplified the river crossing by designing a bridge that spanned the river channel. The money saved after receiving low bids for materials and construction helped them purchase more pipe that allowed them to replace more of the aging siphon. As the previous solution used several piers that were problematic themselves, the new design greatly reduced the number of piers also resulting in less risk of scour and safety hazards to river users.

From a fiscal standpoint, the team also lent its expertise in bidding and came up with an approach that saved $60,000. As Morrison-Maierle’s team also helped write two grants and one loan application (and permit requirements from six regulatory agencies), these cost-saving measures aided in the success of the project.

Finally, this project encompasses numerous renewable resources and benefits to public safety. With a team-centered approach, it now is a benefit to the area’s users, economy, and environment.