Posts Tagged: cold
Dams Ineffective for Cold-Water Conservation - Study of California Streams Reveals Fish Give Dams the Cold Shoulder
Reposted from UC Davis News
Dams poorly mimic the temperature patterns California streams require to support the state's native salmon and trout — more than three-quarters of which risk extinction. Bold actions are needed to reverse extinction trends and protect cold-water streams that are resilient to climate warming, according to a study published in the journal PLOS ONE by the University of California, Davis.
The study helps identify where high-quality, cold-water habitat remains to help managers prioritize conservation efforts.
“It is no longer a good investment to put all our cold-water conservation eggs in a dam-regulated basket,” said lead author Ann Willis, a senior staff researcher at the UC Davis Center for Watershed Sciences and a fellow for the John Muir Institute of the Environment. “We need to consider places where the natural processes can occur again.”
The uncommon cold
Understanding where cold water is likely to stay cold is critical for conservation. But “cold” is more than just a number on a thermometer. The term represents the many factors that combine to create cold water capable of supporting aquatic ecosystems.
Water managers deliver cold water from reservoirs to streams to support aquatic life. But Willis said this assumes that all cold water is the same — akin to giving blood to another person without understanding their blood type and health status.
While previous studies have suggested that dams can be operated to achieve ideal temperatures, few tested that hypothesis against the temperature patterns aquatic ecosystems need.
The UC Davis study assessed stream temperature data from 77 sites in California to model and classify their “thermal regimes,” or annual temperature patterns. It found the state's reservoirs do not adequately replicate natural thermal patterns, making them incapable of supporting cold-water species effectively.
“I'm an engineer; I thought we could operate ourselves into success, but the science doesn't support that,” Willis said. “It's not a question of whether we remove a dam, but which dam, and how we need to restructure how we manage water. Or we need to be willing to take responsibility to be the generation that says, ‘OK, we're letting this ecosystem go extinct.'”
What about the drought?
Drought often tempts people to double-down on hard-infrastructure solutions for water storage.
“We falsely equate dams with water security,” Willis said. “More storage does not mean more water. A giant, empty refrigerator doesn't help you if you're starving. The same is true for water.”
Of California's 1,400 dams, only one very large and highly engineered dam — Shasta — stood out in the study as replicating natural cold-water patterns.
The study does not suggest removing all dams. However, considering removing “deadbeat dams” where there are critical ecosystems could help restore natural processes and support fish, people and biodiversity amid climate warming.
Cold comfort
Key cold-water conservation candidates include streams highly influenced by groundwater, such as in the Cascade Range, and places where water easily infiltrates the soil, such as Northern California's Feather River.
“Classifying these streams and understanding their thermal regimes is an effective way to focus our time and money on the places most likely to make a difference,” Willis said.
The study's co-authors include Ryan Peek and Andrew Rypel of the UC Davis Center for Watershed Sciences.
Funding for this research was provided by internal support from the UC Davis Center for Watershed Sciences and the John Muir Institute of the Environment.
Media Resources
Media Contacts:
- Ann Willis, UC Davis Center for Watershed Sciences, awillis@ucdavis.edu
- Kat Kerlin, UC Davis News and Media Relations, 530-750-9195, kekerlin@ucdavis.edu
UC Davis Community Ecologist Rachel Vannette's New Findings on Flowers
Community ecologist Rachel Vannette, assistant professor in the UC Davis Department of Entomology...
Community ecologist Rachel Vannette's bagged blossoms of California fuchsia in the UC Davis Arboretum and Public Garden led to her discovery of a new species of bacteria, Acinetobacter rathckeae, named for note botanist Beverly Rathcke. (Photo by Kathy Keatley Garvey)
A photo of California fuchsia from the UC Davis Arboretum and Public Garden. (Photo by Rachel Vannette)
UC Davis community ecologist Rachel Vannette discovered a new species of bacteria on this plant, Scrophularia californica in the UC Davis Stebbens Cold Canyon Natural Reserve. The plant is commonly known as "the California figwort" or "the California bee plant." (Photo by Rachel Vannette)
Bernie Sanders Really Did Visit UC Davis
As a presidential candidate, Vermont senator Bernie Sanders visited the UC Davis campus in...
Bernie Sanders in front of the Bohart Museum of Entomology on Crocker Lane, UC Davis campus.
Bernie Sanders on Crocker Lane, UC Davis campus.
Bernie Sanders at Mrak Hall, UC Davis campus.
Bernie Sanders in front of the Robert and Margrit Mondavi Center for the Performing Arts, UC Davis campus.
Bernie Sanders on Kleiber Hall Drive, UC Davis campus.
Bernie Sanders in front of the Harry H. Laidlaw Jr. Honey Bee Research Facility on Bee Biology Road, UC Davis.
It Could Still be a Cold Winter
A moderate La Niña climate phase is expected through spring 2021. This indicates that slightly above average temperatures and slightly less rainfall than normal can be expected in California's avocado/lemon growing areas.
The fact that the winter weather pattern is expected to be warmer than usual doesn't rule out the possibility of a freeze. A freeze can occur any winter, regardless of the climate phase. And dry winters are often susceptible to sudden cold spells because of the lack of tempering effect of soil wet from winter rains
La Niña is one of three climate phases that are part of the El Niño Southern Oscillation (ENSO) climate pattern. Others are El Niño, during which colder and wetter conditions are expected in California, and neutral, when conditions are neither El Niño nor La Niña.
California's most severe freezes have occurred in weak La Niña, weak El Niño or neutral ENSO phases. Severe freezes in Decembers of 1990, 1998, 2001 and 2006 occurred after droughty years and years of low rainfall. In 2015, it snowed in Temecula and again in 2020 – in February!!! So cold weather is still waiting out there.
The most damaging freezes for avocado and citrus are advection and radiation freezes. In advection freezes, cold fronts move arctic air through the region. Radiation freezes feature overnight clear skies and light to no winds with periods of calm. Cold pockets and cold locations will have lower temperatures during radiation freezes. Break freezes and unsettled freezes are the other types of freezes.
During a radiation freeze, cold air drains down and pools in low areas. Know the cold pockets in your grove, and keep that air flowing with a wind machine, if possible.
Read the collected works on frost protection, frost damage and frost recovery here:
https://www.californiaavocadogrowers.com/growing/cultural-management-library/freeze-protection
It's also a good idea to be ready for fires in years of low/no rainfall.
The 2021 Weather Forecast from Fox Weather provided by CAC is below:
Image: Temecula snow on avocados in February
avocado snow Temecula
Landscaping Tips for November
With the recent time change along with a change in temperatures, landscaping practices for pests...