Delta Hydrology -- Delta Actions Team Real-time Assessments

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Current Delta Hydrologic Conditions

Last updated: Monday, March 02, 2026 at 3 PM

Operational and Regulatory Conditions

The current controlling factor is OMRI restrictions to no more negative than -5,000 cfs. See most recent weekly outlook for more information.

Current Conditions

Most recent inflow at Freeport in the Sacramento River and Vernalis in the San Joaquin River is 59,435 and 6,955 cfs respectively. Most recent Jersey Point Flow (JPF) is 9,820 cfs. Most recent 1-day, 5-day, and 14-day OMRI measurements were -5,000, -4,966, and -5,061 cfs, respectively, and most recent export data were 3,551 cfs for Jones Pumping Plant and 1,734 cfs for Henry O. Banks Pumping Plant.

Four-part plot showing hydrologic conditions over time. Top plot shows a time series of flow at Vernalis and Freeport. The upper middle plot shows a time series of Jersey Point Flow, with a horizontal line at 0 cfs. The middle plot shows a time series of daily, weekly, and 14-day average OMRI, with vertical lines and shading to show when actions were taken or thresholds were reached. The lower plot is a column chart showing combined exports from both CVP and SWP. — Figure 1: Operations and Action Summary, WY 2026. The numbers and lines in the OMRI plot indicate different triggers and thresholds (see Table 1), with shading representing specific action periods. Dashed and dotted vertical lines represent triggered actions and thresholds, respectively. OMRI data (colored lines) calculated by SacPAS, Freeport (FPT) and Vernalis (VNS) flow data from CDEC, Jersey Point Flow (JPF) from DWR, and CVP (TRP) and SWP (HRO) exports data from CDEC.

Table 1: Summary of Actions and Triggers, WY 2026

Label	Action	Date Triggered	Date Implemented	Number Days Implemented	Regulation
1	DCC Gate Closure	10/28/2025	2025-10-30	Ongoing	DCC gates
2	First Flush	12/24/2025	2025-12-25	14 days	Entrainment Management
3	Offramp temperature threshold	2/12/2026		3 consecutive days	Delta Smelt Adult Entrainment, no action taken WY26

Zone of Influence

Zone of Influence (ZOI) analysis is discussed in detail in the December 22 assessment. Current conditions were queried from most recent Freeport flow data on the Sacramento River and Vernalis flow data on the San Joaquin river from SacPAS. Forecasted flows were queried from short range deterministic flows provided by the California Nevada River Forecast Center.

Current conditions at Freeport and Vernalis indicate that delta hydrology falls within the ‘hihi’ category. Forecasted conditions averaged across the next 7 days falls within the ‘hihi’ category.

The altered channel length for the current “hihi” hydrology is 99, 100, 119 and 114 kilometers (km) across OMR bins of -2000, -3500, -5000 and <-5500 respectively. The altered channel length for forecasted “hihi” hydrology is 99, 100, 119 and 114 kilometers (km) across OMR bins of -2000, -3500, -5000 and <-5500 respectively.

Change in altered channel length between OMR levels is 15 km for current conditions and 15 km for forecasted conditions indicating that ZOI impacts across OMR scenarios would not change between current and forecasted conditions. Across the nine hydrology bins, changes in altered channel length across OMR scenarios are low (<25th percentile) for both current and forecasted hydrology.

Two-part figure showing results for current hydrology (left) and forecasted hydrology (right). Each map of the Delta shows contour lines for the extent of the hydrologic footprint for different OMRI scenarios (colors). — Figure 2: Modeled Zone of Influence at different OMRI scenarios based on current inflow hydrology (left) and forecasted inflow hydrology (right) from the Sacramento River and San Joaquin River