Abstract
For optimal water delivery and efficient use of water resources in arid landscapes, canal conveyance losses should be minimized whenever possible. This is especially true in southeast Idaho where seepage losses from earthen canals often exceed 50% of total annual diversion and competition for water resources is ever increasing. Quantifying canal losses and locations provides the first crucial step for canal operators in determining how to address the numerous causes of loss and maintain the water delivery systems that communities depend on. In this study, we used a comprehensive approach including: 1) a review of the social, physical and economic irrigation complexities associated with the age-old issue of seepage losses in the Aberdeen-Springfield Canal, 2) the determination of seepage losses, regional aquifer properties and groundwater levels, and 3) an evaluation of the overall effect of the quantified losses in the region. This resulted in discharge and loss rates for every mile of the canal under peak operating conditions totaling 678.0 cfs with 52.5% of losses occurring in the upper 52.9 linear miles of canal. Near the lower end of the canal, aquifer transmissivity of 2 x 105 ft2/day and storativity of 0.0003 were determined. These findings, combined with groundwater levels were used to predict the locations most likely to experience effects of the 195,069.2 af seepage losses that occurred in 2017.