Preparing for a fourth year of drought, NOAA Fisheries takes action with partners for 2015 water operations

Winter 2015

Recent rains in California are a welcome relief to a state stricken with drought. However, similar levels of precipitation must fall consistently throughout the coming winter and spring for reservoir storage conditions to improve to the point of recovery. Since Governor Brown’s drought declaration last January, NOAA Fisheries has worked with federal and state partners to manage the state’s limited water supply as efficiently and effectively as possible—meeting competing demands for human health, agricultural production, and protected salmon and steelhead. Partners have now turned their attention to the upcoming season, seeking to put a plan in place for 2015 water operations. The result of these efforts is the 2015 Interagency Drought Strategy.

The strategy is an interagency effort to manage the state’s two largest water projects—the Central Valley Project and the State Water Project—in 2015, responding to forecasts that drought conditions will persist. The U.S. Bureau of Reclamation (Reclamation), U.S. Fish and Wildlife Service (USFWS), NOAA Fisheries, California Department of Water Resources (DWR), and California Department of Fish and Wildlife (CDFW) collectively reviewed 2014 operations and assessed real time adaptive management decisions to craft a management strategy for 2015 that incorporates the operational flexibility established in 2014 and the lessons learned.

In this collaboration, NOAA Fisheries is focused on protecting Central Valley’s salmon and steelhead populations throughout the drought, ensuring these listed species do not succumb to the state’s water shortages. We are working with our partners to monitor conditions for fish in real time, assessing how listed salmon and steelhead are responding to operational changes and taking action to minimize adverse effects—accounting for both the needs of listed fish and water users.

Here’s what we learned from monitoring salmon in 2014 that will inform our strategies for managing the drought in 2015:   

  1. Managing Old and Middle River (OMR) flow regimes to protect salmon is critically important. Effectively managing flow regimes allows juveniles to stay in the best habitat in the North Delta, ensuring they are not drawn toward the South Delta pumps where they are frequently killed by predators or the pumps themselves. During a rare rainstorm last March, and under a flexible operation approved as part of the 2014 Drought Contingency Plan, we allowed for higher levels of pumping and reverse OMR flows.  Evaluating the effects of the action this fall, we learned that salvage and loss of juvenile Chinook salmon, including winter-run, at the federal and state fish collection facilities increased when OMR’s 14-day running average was more negative than -5,000 cfs. This confirms the importance of managing OMR flows carefully to ensure pumping is increased when it will be most effective for increasing water supply and least impactful to juvenile fish.
  2. Operating the Delta Cross Channel (DCC) Gates affects salmon survival. Studies show that keeping the gates closed during outmigration improves survival because fewer fish are routed through the interior Delta. In 2014, partners developed a plan for operating the gates that relied on a complex set of triggers, including the presence and number of fish in the vicinity of the gates, the tidal cycle, and projected salinity levels. This plan provided adequate protection to listed fish, with the added benefit of protecting water quality by reducing salinity levels.
  3. Temperature management is critical. Salmon rely on cold water, particularly during early life stages when fish are young and vulnerable. Shasta and Keswick dams block endangered winter-run Chinook from accessing their native cold water habitat in the Upper Sacramento and McCloud Rivers, so their eggs and fry are particularly vulnerable to high summer temperatures. Data from the Sacramento River indicate 2014 temperatures were at levels that impact the survival of juvenile salmon and steelhead. We found that the 2014 temperature criterion was exceeded starting in August, resulting in approximately 95% mortality of eggs and fry upstream of Red Bluff Diversion Dam.  As of December 16, 2014, an estimated 390,000 juvenile winter-run Chinook salmon passed Red Bluff, compared to 1.8 million in the previous brood year and 850,000 in brood year 2011, the year of the winter-run collapse (see Nov. 18 USFWS/CDFW/NOAA Fisheries presentation to State Water Board). This is the fewest winter-run Chinook juveniles per female spawner passing Red Bluff in 11 years. 

In addition to these conclusions, 2014 highlighted the need to collect more robust information to improve management decisions made in real time. To address this need, NOAA Fisheries and CDFW developed the Anadromous Fish Monitoring Plan to complement the 2015 Interagency Drought Strategy. The monitoring plan provides specifications for 2015 that will improve monitoring data collection and analysis, based on what we learned in 2014, to improve our understanding of fish behavior and survival in dry conditions.

The monitoring plan proposes adding observation stations at Jersey Point and Prisoners Point to provide information that better informs managers on the relationship between OMR flows and fish entrainment. The data collected at these stations allow managers to make decisions about the timing and duration of reverse OMR flows to minimize impacts to listed fish. The plan also identifies the need for 24-hour sampling at Knights Landing, and increased sampling at Sherwood Harbor and the Sacramento River prior to and throughout the opening of the DCC Gates, to make certain last year’s gate operations plan truly achieves adequate protection for listed fish.

Temperature models provide critical data that inform management decisions, and it is imperative that we have as robust and accurate a pre-season prediction tool as possible.  In 2014, the model’s early season predictions indicated that water temperature compliance thresholds would be achieved at the Sacramento River’s Clear Creek through mid-September. However, observed water temperatures were consistently above the 56°F compliance point by August, subjecting eggs and fry to potentially lethal conditions.  Fortunately, as a precaution, we tripled the small conservation production of winter-run Chinook at the Livingston Stone National Fish Hatchery in 2014. These juvenile fish will be released in early 2015.  This will not, however, mitigate 2014 temperature impacts to winter run in their entirety.

To address the need to obtain improved temperature model forecasts, the 2015 Anadromous Fish Monitoring Plan describes a joint NOAA Fisheries/Reclamation effort to assess the potential for recalibrating the Sacramento River temperature forecasting model.  If recalibrating Reclamation’s model is not possible, the plan identifies the potential for including seasonal forecasts in an alternative model, NOAA and NASA’s River Assessment for Forecasting Temperature model.

The more we learn about salmon and their behavior in the Bay Delta system, the better our management decisions will be. As such, the Anadromous Fish Monitoring Plan goes beyond monitoring to include studies that will improve our understanding of salmon behavior, movement, and survival. This includes NOAA Fisheries’ Southwest Fisheries Science Center’s efforts to enhance DWR’s Particle Tracking Model (PTM) in order to predict the movement of salmon from the Sacramento River into and through the Delta (see Anadromous Fish Monitoring Plan, section B.1.c.). By developing an enhanced PTM that incorporates salmon movement, we will be able to better simulate salmon distribution patterns that can inform real time operations.

In a parallel effort, we are working with Reclamation to implement acoustic tag technology to monitor the movement of juvenile fish in real time. Using real-time receivers, we will be able to monitor acoustically-tagged winter-run Chinook and wild Butte Creek spring-run Chinook as they move down the Sacramento River and into the North Delta. This information will be used to tailor in-season operations accordingly.

The drought has presented the state with considerable challenges over the past few years, and while recent precipitation provides newfound hope that an end is in sight, we must prepare for another season of extreme conditions. This is why NOAA Fisheries is working with federal and state partners to proactively plan for 2015 water operations, building on what we have learned over the past few years to better manage the state’s very limited water supply. The more robust data we are able to collect, the better our management decisions will be; and when we achieve this, we will be better equipped to meet the needs of water users and the state’s threatened and endangered salmon and steelhead runs.

LEARN MORE about water operations in the Central Valley…

LEARN MORE about recovering Sacramento River winter-run Chinook salmon, Central Valley spring-run Chinook salmon, and Central Valley steelhead…

LEARN MORE about the 2015 Interagency Drought Strategy…

Home page photo of Southern California's Santa Catalina Gulf Coast by Mark Capelli