The information on OMR Managment on this website is summarized for Delta Smelt from the OMR Entrainment Management Guidance Document and does not reflect a comprehensive description of each of the OMR actions.

"First Flush" conditions may be triggered between December 1 and January 31 and include: Running 3-day average of the daily flows at Freeport is greater than 25,000 cfs and running 3-day average of the daily turbidity at Freeport is 50 NTU or greater, or real-time monitoring indicates a high risk of migration and dispersal into areas at high risk of future entrainment. This "First Flush" may only be initiated once during the December through January period and will not be required if: spent female Delta Smelt are collected in monitoring surveys.

Turbidity Bridge Avoidance ("South Delta Turbidity"): After the Integrated Early Winter Pulse Protection (above) or February 1 (whichever comes first) and until a ripe or spent female is detected or April 1 (whichever is first), Reclamation and DWR propose to manage exports in order to maintain daily average turbidity in Old River at Bacon Island (OBI) at a level of less than 12 NTU. Reclamation and DWR recognize that readings at individual sensors or localized groups of sensors can generate spurious results in real-time. To avoid triggering an OMR flow action during a sensor error or a localized turbidity spike that might be caused by local flows or a wind-driven event, Reclamation and DWR will consider and review data from other locations.

OMR criteria may control operations until June 30 (for Delta Smelt and Chinook salmon), until June 15 (for steelhead/rainbow trout), or when the following species-specific off ramps have occurred, whichever is earlier.

Delta Smelt: when the daily mean water temperature at CCF reaches 77°F for 3 consecutive days. 77°F is equal to 25°C.