Water’s never really wasted. It always goes somewhere and does something.
See, for example, the lining of the Coachella Canal, on the northeast side of the Salton Sea:
[L]eakage from the unlined Coachella Canal recharged local aquifers. Wetlands have expanded due to spring discharge below the canal. Wetlands were natural features prior to canal construction, but their areal extent has increased substantially due to leakage from Coachella Canal. Lining of the entire canal was completed in early 2007.
A wetland mitigation project has been developed using artificial recharge to maintain adequate flow at the springs, but artificial recharge will amount to no more than 15 to 20% of the canal leakage that occurred before the canal was lined.
From Use of Environmental Isotopes to Determine Impacts on Wetlands Due to Lining of Irrigation Canals, Salton Sea Area, California, ASCE Conf. Proc. doi:10.1061/41173(414)109 B. J. Hibbs, M. Kelliher, and N. Erdelyi