INTRODUCTION
The Auburn Ravine is a unique river when compared to other small waterways that feed the Feather River and Sacramento Rivers. Many western Sierra streams are ephemeral at present and in past history. While the Auburn Ravine was mistakenly classified as ephemeral historically, that classification was based upon faulty assumptions. In reality the Auburn Ravine was fed year round by any number of springs that existed historically. Some of those springs have since been destroyed by man, but some are still in existence. There were no less than five strong springs above Old Town Auburn, at least two smaller springs on the branch that follows Auburn Ravine Road in Auburn, three or more springs that feed the North Ravine, beginning just south of Atwood Road near the Placer County County Jail. Immediately downstream of Ophir Tunnel, two unnamed springs feed year round streams that currently flow into the Ravine as observed by Jack Sanchez, who was born and grew up in that exact location. On the Sanchez property, one or more springs feed what is known to the locals as Myrtle Creek just east of the Lozanos Bridge, crossing Sunset Lane in Ophir. Immediately downstream of Lozanos Bridge, Little Bridge Ravine, fed by multiple springs, one fork of which flows through Ophir Elementary School and the other fork through the grove of alders known to locals as Jiminy Crickets. One or more springs feed Dutch Ravine, running parallel to Highway 193, and joining Auburn Ravine downstream of Gold Hill Road. Two or more springs empty into the Auburn Ravine between Gold Hill Road and Fowler Road, downstream from the Rabe property on Stonewood Road. There are also some smaller springs that exist today between the Fowler Road and the City of Lincoln.
The accumulation of these springs very likely placed a flow from between four and six cfs in the stream throughout the summer months and into the Fall. It is quite possible that the stream was ephemeral somewhere in the Lincoln area although there were numerous wetland ponds that survived the summer located west of Lincoln. It is abundantly clear that the Auburn Ravine from somewhere downstream of Fowler road east to the City of Auburn flowed year round.
Clearly, that makes Auburn Ravine a unique stream as compared to hundreds of small streams that feed the Sacramento and Feather Rivers.
Beginning mid-century during the Gold Rush, the Auburn Ravine began carrying irrigation water from Auburn to the Sacramento River. Thus, the Auburn Ravine began a significant change which allowed the river to contain steelhead and various seasonal salmon runs. It is unclear whether or not there were Spring Run Salmon within its banks, but Fall and Winter Run Chinook were observed through 1987 and up to1992 in one location 2.3 miles east of Gold Hill Road. The period 1987 to present is significant as man-made barriers were put in place and had a very negative impact upon Salmon populations within the Auburn Ravine. That said, at least 25 salmon were spotted below the NID Gauging Station in Lincoln as late as 2010.
There is every reason to believe that Salmon and Steelhead will return in significant numbers as the various barriers are removed and the significant canals are screened.
Minimum flows, however, must be maintained in order to protect the habitat. SARSAS has studied and observed the various flows within the Ravine and has data demonstrating the need to maintain minimum flows no lower than 10 cfs and preferably between 12 to 20 cfs.
RATIONALE FOR SARSAS FLOW RECOMMENDATIONS
First, it is important to understand that no government agency or water district has done more day to day observations and in-stream studies than SARSAS. Also, SARSAS strives to make sure that their studies adhere to good scientific standards. SARSAS has done the following studies: in stream flow rates, temperature measurement, dissolved oxygen levels and ph measurements.
FINDINGS
1. From approximately April 1 through October 15th (during the irrigation season) the daily flow in the Auburn Ravine ranges from a low of 50 cfs to a high of 250 cfs. The typical flow during these months is between 175 cfs and 250 cfs
2. During PGE’s Fall Outage to repair canals, the lowest flow recorded by SARSAS was 1.5 cfs in both 2010 and 2011. Those measurements were taken west of the NID Auburn Ravine 1, known locally as the Gold Hill Dam. In some of the riverbed just west of the Gold Hill Dam, stretches of the river were actually dry with large numbers of fish stranded in deep pools causing SARSAS to rescue countless stranded fishes. Flows in the Auburn Ravine east of the Gold Hill dam were better with estimated flows of between seven and 10 cfs. Flow measurements were not done at that time east of Gold Hill dam.
Measured flows of between 12 and 20 cfs clearly maintain good rifles and deep pools creating significant havens for larger as well as smaller fishes.
3. Water Temperature
During the irrigation season SARSAS has not measured an in-stream temperature above 60 degrees Fahrenheit east of Fowler Road. Water temperatures west of Lincoln do exceed 60 degrees and clearly there is evidence of fewer trout and more warm water
species west of Highway 65. It should be noted that SARSAS perceives habitat west of Joiner Bridge in Lincoln as weak habitat for salmon, rainbow trout and steelhead. SARSAS sees this stretch of river as a highway to spawning grounds east of Highway 193 in Lincoln.
During the Outage water temperatures can and do fluctuate considerably. When flows are in the 1.5 to 4 cfs range, temperatures occasionally rise into the high 60’s and algal bloom will at times be evident. Usually, water temperatures will be cooler during a Fall Outage as daytime temperatures are lower and night time temperatures are considerably lower, helping to keep water cooler. This same trend may or may not occur in the Spring Outages. When the flows are between 4 and 8 cfs, water temperatures tend to be better but not ideal - from 58 to 65 degrees Fahrenheit. Thse temperatures are somewhat equal whether in the fall or spring low flows.
However, when the flows are between 10 and 18 cfs, the fall period will bring water temperatures between 55 and 60 degrees Fahrenheit. And the spring outages will be between 54 and 58 degrees Fahrenheit on average.
4. PH Levels
During the irrigation season the ph level is relatively constant – between 6.9 to 7.2
During a flow of 1.5 to 4cfs, there is wide fluctuation - between 6.6 to 7.8
During a flow between 10 and 18 cfs, there are fairly consistent levels of 7.0 to 7.4
5. Dissolved Oxygen
It should be noted that oxygen levels appear to be most heavily influenced by flow levels as follows:
a. With flows between 18 cfs and 250 cfs, the readings east of Fowler road typically are at or above 58% with a high of 62%. SARSAS usually does not do regular tests when the flows exceed 50 or more cfs as there is little fluctuation in dissolved oxygen levels, and certainly SARSAS has not measured poor oxygen levels when stream flows are above 18 cfs.
b. With flows between 1.5 to 4 cfs, dissolved oxygen levels have been measured as low as 19 % to as high as 30%
c. With flows between 4 and 8 cfs, dissolved oxygen levels have been measured as low as 18% and as high as 45%
d. With flows ranging between 10 and 18 cfs, the dissolved oxygen levels have been measured in the range of 48 to 60%
5. PREDATION
The primary predators within the Auburn Ravine are Grey Heron, Raccoon and fresh water Otters.
During outages SARSAS members and some residents along the banks of the Auburn Ravine have observed the following:
1. Heron have easy access to frogs, crawfish and smaller salmonids
2. Raccoon have easy access to salmonids
3. Fresh water Otter feast at will on salmonids within the shrunken pools
Important considerations regarding flow between Wise Powerhouse and Lincoln
When minimum flows are discussed it is critical to keep in mind the flow from in and around the Wise Powerhouse all the way to the City of Lincoln. It is not unusual during low flows to have a positive flow from the Wise Powerhouse to NID 1 commonly referred to as the Gold Hill Dam. NID has a large canal that removes water from the Auburn Ravine. It has not been unusual during low flows to have the entirety of the Auburn Ravine diverted into that canal leaving the Auburn Ravine below the dam completely without water. SARSAS has pictures(please see attached photos) Thus the only water is what accumulates in deep pools. This is an unacceptable practice as SARSAS has documented fish kills as well as rampant predation. Further, it leaves some of the best steelhead habitat in peril. The distance left dry during these occurrences is approximately 3.6 miles. At the point that Dutch Ravine enters the Auburn Ravine water will exist but at a cfs of approximately 1.5.
SUMMARY
SARSAS has studied the Auburn Ravine over the past four years in order to determine minimum flows that would suggest positive conditions for all riparian habitat, as well as those creatures living along and in the Auburn Ravine. The conclusion SARSAS has reached is flows below 12 cfs are detrimental to all habitat and species living within the Ravine, and, especially to salmonids. During outages two factors stand out as major problems for maintenance of a healthy habitat: 1. Dissolved oxygen levels; and 2. Predation; and, to a degree, water temperature. PH levels are not poor during outages but neither are they ideal.
Therefore, given on-stream observation coupled with electronic measurement of water temperature, dissolved oxygen and ph levels and including issues with predation, SARSAS recommends a range of flow from 12 to 20 cfs. Further, SARSAS finds any flow below 10 cfs as dangerous to the maintenance of a healthy salmonid population.
These recommendations are primarily focused upon the regions upstream of the Hemphill Dam.
Further Considerations
SARSAS recognizes that because the Auburn Ravine has ideal flows created by irrigation water, these conditions are ideal for habitat required by Spring Run Salmon. High flows, coupled with ideal temperatures, excellent dissolved oxygen levels, positive ph levels and a flow that creates deep cold pools enhance a positive habitat for these Spring Run Salmon. The only factor that would inhibit this ideal condition would be allowing flow levels below 12 cfs. That same factor can and should be applied to the threatened steelhead in Auburn Ravine.
Clearly the Auburn Ravine is an excellent stream for trout, steelhead and salmon spawning. The only negative factor regarding habitat is maintenance of a suitable habitat for the salmonid species. Clearly, flow levels below the SARSAS
recommendation should not be considered as viable.
Contact information
Jack Sanchez
SARSAS President
3675 Larkin Lane
Auburn, CA95603
530 888 0281
Jlsanchez39@gmail.com
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