February 3, 2015

Posted on by Po Chi Fung

Feb. 7 Free Workshop:

Advances in Irrigation Efficiency and Soil Treatment

Casitas Municipal Water District is offering a free workshop on February 7, 2015. At the workshop, “Advances in Irrigation Efficiency and Soil Treatment,” experts from Aqua-Flo Supply will offer tips on how to use less water in the landscape through improvements to irrigation and soil. The workshop is appropriate for all types of landscapes and levels of expertise.

The workshop will be held from 9:00 am to noon at the Oak View Park & Resource Center, 555 Mahoney Ave., Oak View. Please call 805/649-2251 x118 to RSVP.

Workshop flier.

Groundhog’s Day Forecast
In his annual Groundhog’s Day email, local researcher Al Leydecker summarized rainfall for the year thus far and the findings of a recent research paper on California’s droughts. Excerpts from his email are copied below. 

“As of today though, things are not looking too good—in spite of all those predictions of a wetter than normal winter. In Santa Barbara we’ve gotten about 7 inches of rain downtown, compared with the long-term average of 9.2 inches for this time of year. In Ojai the numbers are 7.7 inches to date compared with 10.1 on average. So we are down about 25%. That’s the bad news. The good news, for those with hope in their hearts, is that we still have half of our rainy season left to go—typically 50% of our rain comes before Groundhog Day, 50% after. The real bad news, as this applies to California in general, is that the Sierra Nevada snowpack is currently only 25% of normal.
“And the real, real bad news—particularly for our creeks and rivers here in Southern California—comes from a recent paper based on tree-ring studies, by Daniel Grin and Kevin J Anchukaitis (How unusual is the 2012-2014 California drought?). They reached some interesting conclusions: That three-year droughts are not unusual over the last thousand years in California and can occur with as little as a single year between consecutive dry episodes. Over the last 1200 years, they estimate that there have been 37 occurrences of 3-year droughts and a total of 66 uninterrupted dry periods (with every year below the 800 to 2014 precipitation mean) lasting between 3 and 9 years. Further, that ~44% of the 3-year droughts go on to last 4 years or longer. However the 2012-2014 drought stands out. In terms of cumulative severity, it is the worst drought on record . . . and 2014 is the single most arid year in the last 1200 years. But the precipitation deficits of 2014 and current three-year drought are not unique in the paleoclimate record. They did a simple modeling exercise, calculating the average Palmer Drought Severity Index with observed vs. climatological mean temperatures, and their results suggest that temperature could have exacerbated the 2014 drought by approximately 36%. Based on these lines of evidence, they infer that the severity of the 2014 drought is a result of both anomalously low—yet, not unprecedented—water year precipitation and record high temperatures.

“So the critical ingredient may well be temperature. And while the rains may come again, ever increasing temperatures will remain with us. The attached graph shows the change over time in the average annual Santa Barbara temperature (as the annual difference from the overall 1893 through 2014 mean). The change, since Grover Cleveland was President, has been almost 4°F. If Grin and Anchukaitis are correct, all future droughts will be worse than any similar past drought, because of these increased temperatures. This brings global warming home with a vengeance. And as increased temperatures magnify evapo-transpiration, we can expect even lower flows in our region’s creeks and rivers.”