PROJECT ALERT NOTICE (CA) California experiencing another wave of AR storms—Continued: Day 2

Date: Fri, 20 Jan 2017 16:24:41 EST

Summary: Flooding is expected as multiple atmospheric rivers bring heavy rainfall and snow to parts of California beginning today and continuing into next week.

Many counties in central and southern California are under flood or high wind warning today with winter storm warnings issued for high elevation areas in the State. Light to moderate precipitation will continue into tonight and will taper off tomorrow before a stronger storm brings heavy precipitation to the region on Sunday. Currently, streamflow is elevated at numerous gages across the state, with many of those sites predicted to exceed monitor or flood stage at least once during this series of storms.

The California Water Science Center (CAWSC) has 21 crews responding to this event today from the following service areas: Ukiah, CA (4); Eureka, CA (1); Santa Cruz, CA (4); Santa Maria, CA (4); Redlands, CA (3) and Poway, CA (5). Most crews are performing measurements today, but some are performing service repairs or maintenance.

The CAWSC remains in contact with water resource managers from the Bureau of Reclamation, the Army Corps of Engineers, and other partners to coordinate sampling efforts or perform verification measurements during planned flood releases. Today, USGS crews are conducting verification measurements over a range of flows at Prado Dam during planned releases in coordination with the U.S. Army Corps of Engineers, Los Angeles District. A USGS crews is conducting water-quality sampling today for the USGS San Antonio Creek Project, a study that is investigating whether streamflow infiltration during winter storm events is a major source of recharge to the San Antonio Creek groundwater system. Another USGS crew is collecting water-quality samples today in the Los Angeles area for a national characterization study of contaminants of emerging concern in urban stormwater, a study conducted as part of a multi-agency effort that includes the USGS Toxic Substances Hydrology Program and the U.S. Environmental Protection Agency Kerr Environmental Research Center.

The CAWSC hosted a media events today for reporters to accompany USGS scientists and field technician crews as they collect water-quality samples in the Cache Creek Settling Basin, a basin that serves to partially trap sediments and minimize mercury and methylmercury contamination. This work is conducted by the USGS in cooperation with the California Department of Water Resources. Another media event is planned for Monday, January 23 where reporters can accompany USGS scientists and field technician crews as they monitor streamflow and flooding on the San Diego River at Fashion Valley (11023000), a site that is predicted to exceed flood monitor stage later today and again on Monday.

Additional CAWSC crews are planned to deploy over the weekend and into next week in response to these events. No safety issues have occurred during this series of storms and all staff have followed USGS field reporting and safety protocols. Updates will continue to be provided during the course of this event.