While the city of Santa Rosa, Calif., needed to reduce the discharge from its water treatment plant into the Russian River, Calpine Geothermal needed water to replenish the aquifer feeding its geothermal steam fields. The solution seemed simple—build a pipeline to connect the city and the electric utility—but it proved to be complex. Between the two lay 30 miles of premier vineyards and 10 miles of rugged mountain wilderness rising 3300 feet above sea level.
During the growing season, Santa Rosa's recycled water is used to irrigate 6500 acres, but in winter, agricultural demand stops. In 1985, when rains didn't replenish the Russian River, the city exceeded its 1% of volume discharge limit after storage ponds overflowed. The North Coast Regional Water Board issued a cease-and-desist order requiring development of a weather-independent system to dispose of effluent from its Laguna Water Treatment Plant.
At its peak in 1987, the Geysers, the world's largest geothermal steam field, produced energy for 2 million households. As the aquifer feeding the steam field depleted, electricity production declined, supplying only 1 million households in 2000.
It would be 18 years and many options later before the 40-mile pipeline solution would be complete. One of the challenges to starting construction in 2000 was the public's lack of faith in the city's ability to solve the discharge problem, according to Dan Carlson, Santa Rosa deputy director of utilities.
“When we awarded the first construction contract in June 2000, we thought it key to break ground with a picture ceremony of our mayor at the controls of an excavator,” said Carlson, “The pipe was on order and wouldn't arrive until September, but we didn't want implementation of the project to continue as a controversial issue in the coming election season.”
Santa Rosa negotiated an agreement to share the project cost with Calpine Geothermal. The city would build the $184 million pipeline with low-interest State Revolving Fund loans and revenue bonds. Grants funded 2% of the project, while Calpine would build a $50 million water distribution and power system. When the pipeline became operational, Calpine would supply electricity for the three Mayacamas Mountains pumping stations, while Santa Rosa would pay for electricity at the Llano pumping station at the Laguna Treatment Plant.
“Since pumping the 11 mgd would require 8 MW annually to produce 85 MW of electricity, the project was economically feasible,” said Bob Austin, Santa Rosa Geysers operations and maintenance coordinator.
Because this was the county's second largest public works project ever and its largest in 30 years, the city council wanted local contractors and suppliers to have a shot at the business. After meeting with local contracting and engineering associations, the city decided to divide the construction into 10 bid packages generally ranging from $15 million to $20 million each so local firms could compete for the work. Eight contractors, four of them from local Sonoma County, won the 10 contract awards.
“We knew we needed a national firm with significant resources for the design and construction management of this project and chose a team headed by CH2M Hill,” said Carlson. Several local offices of consulting firm CH2M Hill partnered with Winzler & Kelly's Santa Rosa, Calif., office, and assembled a team including several local companies.
“The project could easily have stalled in implementation were it not for the strong technical expertise and the close teamwork with the client and between team members,” said Jane Rozga, CH2M Hill construction manager