Resilience is a system’s ability to absorb a shock and still retain its basic structure and function.

Here, in one complicated table, is an example of the sort of institutional plumbing valves we need to build to increase resilience in the face of drought. It’s a table accounting for the Metropolitan Water District of Southern California’s diversions of Colorado River Water in 2014, water that provided a buffer against California’s extraordinary drought, and it shows how Met essentially doubled the amount of water it was able to take from the Colorado River in 2014 to meet the needs of coastal cities:

The key point to understand is that under the basic Colorado River water allocation rules, Met is entitled to 550,000 acre feet of water per year in a “normal”, non-surplus year, but last year it took more than twice that: 1.18 million acre feet. It did that by invoking a long list of policy widgets that allowed it to either pay for conservation in other places, or to conserve water in previous years that was banked in Lake Mead for later use.

• 113,400 acre feet of water saved by lining canals in the Imperial and Coachella, the region’s two big ag water districts
• 100,000 af saved by fallowing land in Imperial
• 67,700 af saved by lining the All-American Canal
• 338,500 af that had been saved through conservation efforts and banked in Lake Mead

Each one of these widgets is the result of the unglamorous work of building personal and institutional relationships among water users and agencies, many of them across the difficult ag-urban interface. They were built over time, and are now available when they’re needed. They have added resilience to the system.