The Northern California city of Santa Rosa sits just below the Mayacamas Mountains in Sonoma County, where some of the best wines in the world are produced. For years the city of 169,000 used its treated wastewater for crop irrigation; the rest flowed into the nearby Russian River. But when the river overflowed one too many times, Santa Rosa officials were forced to start looking for another way to dispose of the city’s surplus water.
Read the May issue of Governing magazine.
High in the nearby Mayacamas, steam rises from muddy pools called fumaroles. In the 1850s, a grizzly bear hunter stumbled upon these bubbling hot springs and mistakenly identified them as “geysers.” The name stuck. Energy companies have been generating electricity commercially in the Geysers since 1960, and today, the Calpine Corp. operates 15 geothermal plants here.But the underground reservoirs are slowly being depleted. Only 20 percent of the steam captured and sent through the generators can be returned to the ground as water. The power company’s need for water and the city’s need to dispose of its water gave rise to the Santa Rosa Geysers Recharge Project, a $200 million engineering feat that took three years to complete. (And that was after the city spent years dealing with a number of lawsuits to stop it.)
The project, which began operating in 2003, uses wastewater to replenish the steam reservoir. Highly treated wastewater is pumped 41 miles from Santa Rosa up into the Mayacamas, where it is injected deep into the ground. On the way, it passes under the Russian River and the environmentally sensitive Mayacamas Mountain Audubon Sanctuary.
It’s a major effort that sends more than 12 million gallons of recycled water to the steam fields each day, boosting Calpine’s output enough to meet the energy needs of 100,000 households.
