Water Banking

Water Banking

As another hedge against water shortage and climate change, the Southern Nevada Water Authority has entered into a series of “Water Banking” agreements with other the Lower Basin Colorado River states, Arizona and California. In these agreements, Nevada pays the other Colorado River water rights holders to store unused water in times of surplus by injecting it into aquifers. Nevada then receives credits for the stored water; if the water is needed, Nevada uses the credits to draw the equivalent water from Lake Mead, and in exchange, the “banker” withdraws the same amount from the aquifer. Although pumping is energy-intensive, groundwater banking does not require the construction of large reservoirs, and the water is not subject to large evaporative losses.

In its water banking agreement with Arizona, the SNWA paid $100 M initially and began making yearly $23 M payments in 2009 that will continue indefinitely. The agreement allows the SNWA to withdraw up to 40,000 acre-feet per year. In 2004, SNWA also began a water banking agreement with the Southern California Metropolitan Water District (the water district that serves L.A.) in which some of Nevada’s surplus Colorado River water is stored in an aquifer in Southern California. The agreement allows the SNWA to withdraw up to 30,000 acre-feet per year, provided that they give 6 months notice. Since 1987, Southern Nevada has also been banking its own surplus water – when available - in the valley’s aquifer for later use if needed. In Nevada, about 333,000 acre-feet have been stored through 2022, and in Arizona’s aquifer, the SNWA has stored 614,000 acre-feet of the Colorado River’s water through 2023.