abstract
- © 2019, The Author(s).The construction of the 42-km long All-American Canal in southern California (USA) near the border with Mexico in the 1940s generated infiltration which raised groundwater levels in the area inducing groundwater to flow into the Mexicali Valley aquifer (Mexico). In the late 2000s, the USA started a controversial lining project to reduce infiltration below the canal, with far-reaching consequences. This investigation implemented a numerical groundwater flow model to determine the hydrodynamic effects of the lining of the All-American Canal on the Mexicali Valley aquifer. For this purpose, plenty of information was acquired with a 32-year span of data and 88 monitoring wells in the area of interest. Field evidences and the model approach suggest that seepage from the All-American Canal resulted in the rise of groundwater levels to 14 m in the northern Mexicali Valley aquifer. However, continuous drawdowns were observed after concluding the lining in 2008, with the result of a drop in the water table to 5.8 m after 4 years of monitoring. A forecast shows that groundwater levels will tend to stabilize to those levels that existed prior to the infiltration produced by the canal. At the existing wetlands in the Mesa de Andrade in Mexico, a 1-m drawdown will be registered due to the lining, which could affect the existing ecosystem. Any additional extraction done on the Mesa de Andrade will likely dry the wetland.