Swelled by heavy runoff from recent large storms, Lake Cachuma is expected to fill and spill by this weekend, according to Santa Barbara County officials.

The lake level continued to rise at the rate of about one foot per hour on Tuesday, and by 7 p.m. was at 78% of capacity, and about 15 feet below spill level, according to the county Public Works Department.

“We’ll still be getting inflows to the lake for the next few days,” an obviously happy Matt Young, manager of the county Water Agency, told Noozhawk.

“Just in the last day, it’s come up 34 feet, which is pretty unbelievable.”

Young estimated the lake will reach capacity and begin sending water over Bradbury Dam Friday night or Saturday.

The last time Cachuma spilled was in 2011.

The change in fortunes for Cachuma — and the other upstream reservoirs on the Santa Ynez River, Jameson Lake and Gibraltar Reservoir — is good news for the county’s water supply.

As of early December, Cachuma was at only about 30% of capacity, and water agencies that rely on it were told they would receive no new water allocations from the reservoir this year, Young said.

That will all be revisited and undoubtedly change once Cachuma fills.

It’s also likely local water agencies will receive larger allocations of State Water due to the heavy snowpack in the Sierra Nevada, which will help fill Northern California reservoirs.

More water flowing over the dam at Cachuma also is good news for communities downstream along the Santa Ynez River. The increased flows will help recharge depleted groundwater basins in the Santa Ynez and Lompoc valleys.

However, Young stressed that groundwater basins throughout the county have been drawn down and stressed by pumping during the recent drought, and will need several years of good rainfall to fully recover.

More rain is forecast for the county over the weekend, although nothing of the magnitude of the most recent storm.