Monday, October 18, 2021
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Marin utility orders water pipeline design


The Marin Municipal Water District has authorized the full design of a water pipeline across the Richmond-San Rafael Bridge in case its reservoirs go dry next summer.

The board’s unanimous approval of the $1.25 million design contract marks one of several significant investments the district will consider to have the 8-mile pipeline in place in July.

District forecasts show its main reservoir supplies could be depleted by July should the area experience a third consecutive dry winter this year. The district serves 191,000 residents in central and southern Marin.

While board members noted the design contract is an investment, it is not the final approval for the project.

“Going forward with this doesn’t mean we can’t go in another direction,” Cynthia Koehler, the board president, said on Tuesday.

The design contract was awarded to Canada-based WSP Global Inc., which received $154,500 from the district earlier this year for preliminary design studies of the pipeline. The contract approved this week also includes a contingency of about $208,000.

The full design is expected to be completed in late February, according to the contract.

The estimated $60 million to $90 million pipeline across the bridge would bring in water purchased from Sacramento Valley agricultural producers. The water purchases are still under negotiation.

Using a network of canals, pumping sites and reservoirs, the water would travel more than 100 miles to the East Bay before being pumped over the bridge from Richmond into Marin. The district intends to pay for the project by issuing bonds.

The district is working under a breakneck schedule to design, permit and construct the pipeline by next summer. This schedule will require the board to decide whether to make an estimated $18 million to $25 million investment in piping and other construction materials at its Oct. 19 meeting. Materials need to be purchased early to ensure that they are manufactured and ready for construction use by early 2022, according to district staff.

An estimated $40 million construction contract might go to the board in January should it decide to proceed with the project.

Unlike other Bay Area water suppliers, the Marin district relies on seven local reservoirs for 75% of its water supply. Those reservoirs are now just a third full. Water imports from Sonoma County that make up the district’s remaining supply have been cut by 20% because of the drought and could be curtailed further if conditions worsen.

The water district built a pipeline across the Richmond-San Rafael Bridge in 1977 when it faced running out of water supplies. At that time, the pipeline lay on the top deck of the bridge, where the bicycle and pedestrian path is now. The pipeline was removed in 1982 at the request of Caltrans so the space could be used for traffic.

This time around, the district and Caltrans determined the best placement for the pipeline to be the underside of the top deck. This is in part because the pipeline might become a permanent fixture of the bridge that can be used in future droughts.

Paul Sellier, the district operations director said, this configuration is preferred because it “preserves the current and future uses for the bridge.”

While Sellier said a cost comparison between the two configurations was available in the Caltrans assessment, he did not release it this week because it has not been presented to the board. He said the cost difference “is not as much as people might think.”

It will presented at the board’s Oct. 19 meeting.

“While Caltrans is still reviewing alternatives, attaching the water pipe under the top deck makes sense because it would continue the benefits of the bike path and require fewer permits,” Caltrans District 4 spokesman Vince Jacala said.

The bike path, which opened in late 2019, is part of a four-year pilot project led by Caltrans, the Bay Area Toll Authority and the Transportation Authority of Marin. At the end of the pilot phase, officials will determine whether to continue operating the bike path or potentially convert it into a third lane of westbound traffic.

Sellier said the preferred pipeline configuration would allow these uses to continue while also allowing Caltrans to more safely use its bridge inspection equipment.



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