The Contra Costa County Board of Supervisors on Tuesday approved laying off more than 30 library workers and adjusting county library branch hours in response to some Contra Costa cities saying they will cut some or all of their funding for extra library hours.

The county library system provides a baseline 35 open hours each week at each of the system's 26 branches. While the baseline library hours are paid for from countywide property tax revenue, 10 Contra Costa cities last year paid extra to have their libraries open more hours per week.

Those cities, according to a county staff report, are expected to contribute a combined $700,000 less than the $3.38 million included in the county's preliminary 2020-21 budget.

As a result, the supervisors on Tuesday approved cutting 39

positions -- seven of them vacant -- and cut extra open library hours, in most cases, from four to 10 hours a week per branch.

Hours at the Brentwood library, however, are to be cut from 56 open hours a week to 35, county Librarian Melinda Cervantes told supervisors, and Walnut Creek is expected to make a similar drastic funding reduction for extra open hours, which Cervantes said will likely require further cuts.

Library open hours, even at libraries where cuts aren't happening or are relatively minimal, are changing at most branches to provide for relatively uniform Tuesday-through-Saturday schedules. Cervantes said library staffing has already been "lean" before these cuts were approved.

The funding numbers could be further revisited, county officials said Tuesday, as most of Contra Costa County's 19 cities have not yet finalized their 2020-2021 budgets. But every city is expected to make budget cuts from 2019-2020, as the COVID-19 coronavirus shelter-in-place order has decimated municipal sales tax, real estate transfer tax and gas tax revenues.

County Administrator David Twa told the supervisors Tuesday that many of the displaced library employees will have the opportunity to shift to other county jobs, including some other vacant library positions, clerical positions, eligibility worker spots and as "contact tracers" who work to identify the people who have come in contact with those who have tested positive for COVID-19.

The Board of Supervisors has postponed approval of its 2020-2021 budget, usually done each June, until August this year because of complications and added expenses tied to the COVID-19 pandemic.