Hi, a stakeholder requested this report recently so we thought we’d post it here. This is the final report from Cramer Fish Sciences (sponsored by the Water Forum) on impacts of reduced LAR flows on last winter’s emerging Chinook Salmon. As always, please don’t hesitate contact one of us if you have questions or concerns.
Final Embyo Impacts, Cramer Fish Sciences
Nature has been a friend to the Steelhead these past few days. The cooler air temperatures (coupled with Reclamation’s power bypass) have resulted in healthier conditions for incubating Steelhead.
The results of recent field work indicate that the recent hot spell has NOT been lethal to the incubating Steelhead in the lower American River. Actions by Reclamation to keep water temperatures and reduced daytime air temperatures are responsible for this favorable outcome.
Water Forum staff and consultants have estimates that 85% of the 2015 brood of have Steelhead emerged at this point.
Given this positive news and predictions of cooler weather ahead, Reclamation told stakeholders in a special session of the American River Group today that they will continue releasing 500 cfs from Folsom for the foreseeable future and will continue the power bypass until middle of next week. After that, the chunk of cold water accessible to the bypass will be mostly used up and Reclamation will end it.
Here is a graph showing that air and water temperatures declining yesterday.
River temperatures on Sunday remained high. This is due to record warm daily temperatures and windy conditions. The wind apparently stirred up Lake Natoma and and resulted in warmer water being released from Nimbus (see the Hazel temperature spike below). As reclamation operator said, “wind is not our friend.”
Today we had some decent cloud cover, and tomorrow we expect cooler days and the cooler water from Folsom power bypass will show up.
You can see the wind gust on Saturday in in this graph:
Folsom Lake Storage is dropping slowly as inflow continues to diminish. Note that the 24-hour pulse flow (for temperature management) resulted in the release of approximately 600 AF.
Our field folks gathered temperature data at Rossmoor on Saturday 3-28-15. You can see that conditions continued to be warm on Saturday 3-28, but not as warm as Friday 3-27. We don’t have the Sunday Rossmoor temps yet, but the William Pond temperatures indicate that we had some cooling on Sunday 3-29. I con’t explain why Hazel temps jumped on Sunday.
Reclamation operators solicited opinions from State and Federal biologists and Water Forum stakeholders during a special session of the American River Group (ARG) on Friday March 27. Meeting participants advocated for a range of possible actions: from keeping flows at 500 cfs to increasing flows to 800 cfs for a number of days.
One of the key items of discussion was the observed river temperatures at Rossmoor Bar and foretasted warm days over the weekend. This graphic (complements of the Water Forum) was presented to illustrate the relatively high river temperatures and the warm weather forecast:
After discussion and data sharing, Reclamation chose to initiate a power bypass (lower river outlets) to send colder water downstream AND send an 800 cfs pulse of of water for 24 hours. NMFS staff concurred with the plan. The intent of the pulse is to reduce the travel time through Lake Natoma and get the colder water down to the gravel as quickly as possible. This is especially important given the predicted warm weather over the weekend.
The Sac Bee had an article about the issue today [Click Here].
You can see the lower release temperatures in this graph:
This graph shows the start of the pulse flow:
Several people let me know that I had a typo in the temperature thresholds given in a previous post. Here is a correct – and more comprehensive – list of temperatures and their effects on incubating Steelhead:
Following are two graphs that illustrate projected Folsom Lake storage and LAR Flow.
- Folsom storage peaked 575.4 TAF on March 16.
- Reservoir inflow had been declining rapidly since around Feb 9.
- With the LAR flow cuts (100 cfs drop each day on 3-24 thru 3-26) the the reservoir outflow comes pretty close to matching the inflow.
- However, Reclamation projects that inflow will continue to wane and storage will drop through the end of March.
- Storage will peak again at under 600 TAF by the end of May.
- Storage may drop as low as 150 TAF by the end of November.
Notes: These graphs are based on the information distributed by Reclamation on 3/19/15 (see post below from that date). We have “discounted” the Folsom stroage by 35 TAF to correct for the actual LAR flows during the first part of March (Reclamation scenario was based on March flow at 500 cfs all month; actual flow was 800 cfs through the 21rst).
Here are the latest water temperature data. Note that we were above the healthy zone (above 57 deg F) and into the lethal zone (above 59 deg F) for several hours yesterday at Rossmoor Bar and at William Pond. Temperatures upstream are expected to be cooler.
Note also: the gravel and water gauges at Rossmoor are measuring warmer than the cdec gauge at William Pond. We assume this is because the Rossmoor gauges are more affected by direct sunlight.
- Hazel: AHZ cdec gauge.
- William Pond: AWP cdec guage.
- Rossmoor Water: Water Forum temporary gauge – average of three sites; each gauge is installed in white, slotted PVC pipe at gravel surface.
- Rossmoor Gravel: Water Forum temporary gauge – average of three sites; each gauge is installed in white, slotted PVC pipe at about 12 inches deep in the gravel.