Santa Rosa officials have picked a new consulting firm to lead the development of an emergency water supply for the city following a contract dispute with the Sebastopol firm that managed the effort for years.

A city selection panel is recommending West Yost Associates of Davis to head up the next phase of plans to significantly increase the city's groundwater supply. The choice still needs to be affirmed by the Board of Public Utilities next month.

The project aims to ensure the city has a backup water supply in the event access to Russian River water is cut off, such as in an earthquake or severe drought. The city has spent more than a decade and an estimated $10 million studying the aquifer for possible well sites but has yet to build any new production wells.

The city last fall held up payments to its previous contractor, environmental consulting firm ECON, after it realized that ECON's owner, Andrew Rodgers, is not a licensed geologist, hydrologist or engineer.

Rodgers managed the drilling and analysis of test wells in various locations around the city from 2008 until last year. He didn't need to be personally licensed because he hired licensed engineers to do the majority of the work, he said.

Despite the dispute, which is ongoing, ECON will still have a role in the next phase of the project, said Andrew Allen, the city's supervising engineer on the program.

ECON is one of several firms West Yost is tapping to help it complete the project, Allen said. West Yost and ECON both worked closely with the city on its groundwater master plan.

ECON has a database that might prove useful in identifying areas to site wells, Allen said.

However, because of the licensing issues, the city "cannot use them for geologic services or engineering services," he said.

"We certainly have done our due diligence to determine what type of work they can do on the project," Allen said, describing ECON's future role as "focused."

The West Yost official in charge of the project, Vice President Gerry Nakano, could not be reached for comment. Rodgers said he couldn't discuss his future role because he's not the project manager.

He said he is "working through" his dispute with the city over his previous contract for test wells.

The new contract with West Yost, worth an estimated $3.5 million, is both more expansive and narrower than the previous arrangement with ECON.

In addition to continuing the search for suitable well sites, the new contract also calls for West Yost to bring four new wells online within three years and explore other supply options such as recharging the aquifer in the winter to ensure water is available in the summer months.

But the contract is narrower than ECON's because future test wells, production wells and other facilities will be bid separately, Allen explained.

Under the old contract, ECON hired well drillers as subcontractors. But because the work was considered exploratory, Rodgers didn't have to pay prevailing wages as required for public works projects.

The city's groundwater master plan in 2013 estimated the cost of developing the needed 8.4 million gallons of additional emergency supply at $27 million. The first phase of that effort, including installation of four new wells and an aquifer storage feasibility study, was pegged at $8.7 million.

That figure is likely low, however, because it does not include the cost of additional test wells, Allen said.

Aquifer storage and recovery involves man-made systems such as infiltration basins or injection wells that increase the amount of water stored underground for future uses.

(You can reach Staff Writer Kevin McCallum at 521-5207 or kevin.mccallum@pressdemocrat.com. On Twitter @citybeater.)