Looking back on 2014, it’s hard not to feel despair for California salmon.
With drought-stricken rivers running dangerously warm and slow for spring migration, the government was giving millions of young hatchery salmon a lift to the Pacific by truck and barge. Come August, several streams in the Central Valley were drying up. Native fish were absent from many of their summer haunts.
There was, however, a startling exception to the run of bad salmon news.
On the Shasta River, a lifeline for Siskiyou County cattle ranchers, more than 18,000 fall-run Chinook salmon returned from the ocean. That’s more than double the return from the previous fall. More importantly, average returns during the past four years have quadrupled.
No one knows for sure why salmon are surging in the Shasta; many factors affect salmon population dynamics. However, one of those factors — the condition of freshwater habitats — dramatically improved following the exclusion of cattle from a spring-fed tributary, Big Springs Creek.
Historically, the creek had been a poster child for salmon habitat. Its water originates from springs fed from the snow-capped Mount Shasta, elevation 14,162 feet. As snow melts, it flows underground through porous volcanic rock, rather than running off in streams. Water eventually bubbles up, forming the creek, at about 55 degrees (12 degrees C) — just right for salmon and steelhead trout.
Enriched with nitrogen and phosphorous from volcanic and sedimentary rock, the spring water nourishes an abundance of aquatic plants that teem with insects. The plants provide good cover from fish-eating birds and a respite from high-velocity currents. Fish can eat bugs at their leisure. They grow exceptionally fast and big, increasing their chances of survival when they leave for the ocean and return to the creek to spawn.
All 2.2 miles of Big Springs Creek flows through a cattle ranch that has been operating for more than 100 years. During that time, the luxurious habitat gradually deteriorated. Cows trampled banks and spawning beds and stripped streamside vegetation. They devoured the aquatic plants, making the creek shallower and inhospitably warm in the summer.
The Nature Conservancy had long eyed the Shasta Basin because of its potential to provide high quality habitat for native salmon and steelhead — particularly coho salmon, which are federally designated as “threatened” with extinction. Historically, the 60-mile-long Shasta River was one of the most productive salmon streams in California. As a tributary to the Klamath River, the Shasta contributed only 1 percent of the flow but supported 50 percent of the Chinook salmon (NRCS 2004).
Little was known about the ecology and hydrology of the Shasta River because nearly all of the watershed is privately owned. But a research opportunity arose after the Nature Conservancy bought the 1,700-acre Nelson Ranch, in 2005. The U.S. Bureau of Reclamation, a Klamath Basin dams operator obligated to protect imperiled fish, commissioned the UC Davis Center for Watershed Sciences and Watercourse Engineering Inc. to do a baseline assessment of conditions for salmon and steelhead.
The study confirmed that the river through Nelson Ranch “provides unique and potentially very high quality habitat for rearing juvenile salmonids,” but found the water too warm in the spring and summer for young coho (Jeffres et al. 2007).
Significantly, the 2007 report suggested that temperatures could be improved by repairing Big Spring Creek, just upstream of Nelson Ranch. Researchers found that the creek contributes most of the Shasta’s summertime flow and strongly influences its temperatures for as much as 14 miles downstream (Nichols et al. 2014).
Two years later, in 2009, the Nature Conservancy bought all but 407 acres of the 4,543-acre Shasta Big Springs Ranch along the creek. The organization leased the pastures so ranching could continue, but fenced the entire stream.
Results of the cattle exclusion were dramatic.
In just the first year, the creek transformed from wide, turbid and shallow to cool, clear and deep. Without the constant grazing, the aquatic plants began to grow back, providing shade, protective fish cover and insect habitat. As of last fall, just five years later, annual maximum water temperatures had declined by as much as 7 degrees (4 degrees C) – a substantial and rapid improvement.
Likewise, the extent of suitable, connected salmon and steelhead habitat has increased dramatically throughout the creek — and for miles downstream in the Shasta River. Young coho are now seen at several sites in the creek and river, compared with surveys of 2008, when they were observed only in a single pool at the creek’s headwaters.
Video of Chinook salmon in Big Springs Creek by Carson Jeffres, UC Davis, 2012
The Shasta Basin strategy has useful implications for stream recovery efforts elsewhere. While it’s tempting to focus on the livestock fencing as the solution, three cornerstones laid the foundation for success:
- An earnest and transparent scientific process to identify ecologically high-value sites and key limiting factors
- Acceptance of the scientific process, with its uncertain timelines and outcomes, by recovery project funders and interest groups
- Commitment to implement a solution that maintains the economic well-being of riverside landowners – in this case, cattle ranchers.
Together, these elements paved the way for scientific discovery, both in identifying the major ecological impairments and determining how to address them.
With habitat recovery in Shasta Basin now underway, other basin landowners can help sustain it. Salmon restoration efforts in the region already enjoy broad support and collaboration among public, private and non-profit entities. Several measures are already established, including controls on irrigation runoff, removal of barriers to fish passage and water transactions that increase streamflows for fish at biologically important times.
Conservation activities at the basin scale are necessary to develop and maintain salmon and steelhead habitat. However, certain ecologically important river reaches are paramount to successful recovery. Good stewardship of these critical reaches leverages the value of all conservation efforts in the basin.
Ann Willis, an engineer and research coordinator with the UC Davis Center for Watershed Sciences, wrote this article with contributions from the center’s Peter Moyle, professor of fish biology, and Michael Deas, president of Watercourse Engineering Inc. of Davis. Center researchers Robert Lusardi, Carson Jeffres and Andrew Nichols also contributed.
Jeffres CA, Dahlgren RA, Kiernan JD, King AM, Lusardi RA, Nichols AL, Null SE, Tanaka SK, Willis AD, Mount JD, Moyle PB, Deas ML. 2009. Baseline Assessment of Physical and Biological Conditions Within Waterways on Big Springs Ranch, Siskiyou County, California. Center for Watershed Sciences, UC Davis
Jeffres CA, Mount JF, Moyle PB, Deas ML, Buckland E, Hammock B, Kiernan JD, King AM, Krigbaum N, Nichols AL, Null SE. 2007. Baseline Assessment of Salmonid Habitat and Aquatic Ecology of the Nelson Ranch, Shasta River, California Water Year 2007. Center for Watershed Sciences, UC Davis
Lusardi RA and Willis AD. 2014. Aquatic plants: unsung but prime salmon habitat. California WaterBlog
Lusardi RA. 2013. How to save salmon: Location, location, location. California WaterBlog
National Research Council (NRC). 2004. Endangered and Threatened Fishes in the Klamath River Basin: Causes of Decline and Strategies for Recovery
Nichols AL, Willis AD, Jeffres CA, Deas ML. 2014. Water Temperature Patterns Below Large Groundwater Springs: Management Implications for Coho Salmon in the Shasta River, California. River Research and Applications, vol. 30 (4)
Willis AD, Nichols AL, Jeffres CA, Deas ML. 2013. Water Resources Management Planning: Conceptual Framework and Case Study of the Shasta Basin. Center for Watershed Sciences, UC Davis
Willis AD, Deas ML, Jeffres CA, Mount JF, Moyle PB, Nichols AL. 2011. Executive Analysis of Restoration Actions in Big Springs Creek March 2008-September 2011. Center for Watershed Sciences, UC Davis
U.S. Environmental Protection Agency. 2003. EPA Region 10 Guidance for Pacific Northwest State and Tribal Temperature Water Quality Standards