This isn't the first year California has been in a serious drought. I got my first lesson in business sustainability from the Truckee River. The Truckee flows out of Lake Tahoe, through Reno, and into the desert, and during the late 1980s and early 1990s, a shortage of snow pushed the lake level down. In 1994 the Truckee, which is the lake's only outlet, channeled only about 32 cubic feet of water per second, barely enough to keep its rocks wet.

The river recovered and today, pushes five to 10 times as much water on average as it pushed during that low point. But it recovered only because more snow eventually fell, raising the lake level and strengthening the flow. Credit unions have experienced a similar loss in snowmelt; as income from net interest margin has dried up, more has had to come from noninterest income. But rather than waiting on the clouds, many have been building enough NII to guarantee that the river of net income doesn't run dry. As they look for additional sources, they need to be sure they're giving members value, not just extracting it.

Filene recently conducted research seeking to balance two important credit union imperatives: the need for NII that supports the operating costs of the credit union, and the imperative that credit union leaders feel to charge fees that are fair and that support services that add value to members. The tension is real. Too many or ill-advised fees and credit unions run the risk of alienating members and losing their cooperative difference. Not enough NII and profitability, like the Truckee, will dissipate.