The rainstorms that visited San Luis Obispo County over the Christmas weekend dropped an average of 2 inches of rain. This was enough to noticeably increase the amount of water stored in two of the county’s reservoirs, but the rain added only negligible amounts of water to the other two. None of the reservoirs in the county are full.

Nacimiento Lake and Santa Margarita Lake, both of which are fed by large watersheds, increased their storage by about 2 percentage points to about 40 percent and 60 percent, respectively. Lopez Lake is about 75 percent full, and Whale Rock Reservoir is about 70 percent full. Both of these are fed by smaller watersheds.

Another benefit of the recent rains has been the return of a flowing Salinas River in the North County.

The San Luis Obispo County Public Works Department said that the “live stream” was officially recognized at 7:30 a.m. Thursday.

The river was flowing from Santa Margarita Lake to the confluence with the Nacimiento River northwest of San Miguel.

The distinction is important: Under a 1973 ruling by the state Water Resources Control Board, once a live stream is declared for the Salinas River through the North County, the outlet gates in the dam forming Santa Margarita Lake can be closed. When that happens, any water flowing into the lake (also called Salinas Reservoir) gets stored for use by the city of San Luis Obispo.