From American River Group Meeting March 19, 2015.
Reclamation update on hydrology and weather:
- Rain: low.
- Folsom storage: not bad at the moment.
- Snow pack: really bad.
Conclusion: 2015 may be a worse water year for AR basin than 2014. The reservoir is higher now (than last year) because, “we got our paycheck early,” in the form of wet, early-season precip. However, “we don’t know when we will get paid again.”
Additional notes from Reclamation:
- Low Storage point on chart is 188 TAF end of Nov.
- That value is probably close to 153 TAF when you consider that the flows for most of March were actually 800 cfs (it represents about 35 TAF of unaccounted outflow).
- These numbers could be worst given the recent weather forecasts.
- This projection assumes minimal CVP export pumping (health and safety of M&I only).
- This projection assumes some of the TUCP actions that have yet to be approved.
- The biggest “swing” in the data is assumptions of Sac Valley “depletion” and Delta Water Quality requirements (which are subject to future TUCPs).
- The biggest fishery concern over the next 4 to 6 weeks is incubating Steelhead: eggs and alevin in the gravel.
- If temperatures in the gravel get above 47 degree Fahrenheit (47 dF), then the incubating Steelhead get stressed and some may die.
- If the gravel temp gets aboe 59 dF the Steelhead eggs and alevin that are maturing there are likely to die.
- This is bad since they are a listed (Theatened) species.
- Keeping temperatures in the river low now is more important than saving cold water for later because of the high sensitivity of egg & alevin.
- We want to keep temps below these thresholders while there are still Steelhead in the gravel. This means at least through the first week in April and preferably through the end of April.
- Biologist have estimate when the Steelhead will emerge (leave the gravel): see chart below.
- The 2014 brood of Fall Run Chinook is believed to be fully emerged (out of the gravel) and are out-migrating now. They are less sensitive to flow and temperatures that Steelhead right now.
Estimated cumulative proportion and number of fry to emerge by date for observed Lower American River Steelhead redds through 20 March 2015:
Conclusion after group discussion:
- Reclamation will reduce flows to 500 cfs, starting at 1 am on Tues 3/24/15.
- Flows will be dropped 100 cfs each day.
- Drops will be made in the middle of the night to reduce fish stranding.
- Reclamation will “do their best” to keep water temperature at Rossmoor Bar below 57 dF though the first week in April.
- Temperature management available to Reclamation: use of lower river outlets (power bypass), shutter pull, flow change.
- There is not a permanent temperature gage at Rossmoor Bar.
- Reclamation will continue stranding surveys over the next several weeks.
- Water Forum (at Reclamation’s request) will conduct temperature and water quality monitoring.
- Water Forum (at Reclamation’s request) will make our Rossmoor Bar temperature data available to Reclamation (we’ve had a non-permanent temp gage there for a few years).