The All-American Canal (AAC) in southern Imperial County, California, has historically been unlined, resulting in substantial losses to seepage. In 2006, the Imperial Irrigation District (IID), under a contract with the United States Bureau of Reclamation (Reclamation), initiated a project to build a concrete-lined canal parallel to 23 miles of the earthen AAC. Construction was completed in 2010, and was estimated to conserve about 67,000 acre-feet per year of seepage. Since 2009, groundwater levels and groundwater storage in the vicinity of the canal have decreased substantially. Repeat microgravity measurements provide estimates of storage change independent of aquifer porosity or depth to water. Measurements also provide estimates [...]
