With all of the water in the western United States spoken for, there’s an increasingly common problem in water policy and politics discussions in which a seemingly simple solution to a water problem in fact just creates a different problem somewhere else.

An article in the March/April Southwest Hydrology from my old stomping grounds of eastern Washington nicely makes the point. Bob Brower and Aristides Petrides write about what happened when 23 miles of irrigation canals in the Walla Walla Basin were piped or lined to reduce water losses.

What the found was that the water “lost” when it drained into the ground from unlined canals was not being lost at all. Springs and seeps that were being fed by the “lost” water went dry:

This seemingly successful restoration overlooked an important aspect of surface-water management: the role of groundwater. As conservation measures were implemented, the spatial distribution, timing, and volume of recharge to the shallow aquifer system changed. In fact, surface water gains observed in the main tributaries can generally be attributed to a net loss of aquifer recharge. This is because significant amounts of water that used to infiltrate throughout the watershed now flow directly into the river.

There are often, in other words, unintended consequences.