| | Published September 28th, 2011
| Orinda's Rain Trackers
| | By Andrea A. Firth |  | | From left: Allen Prager, Lynn Trowbridge and Susan Watson Photo Andy Scheck
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By the end of our Sunday morning walk, my husband and I were soaked. Well maybe not soaked, but we were wet. We had hiked the last ten minutes in the rain, not a downpour, but fat, heavy raindrops fell steadily all around us. That was September 11th. Rain already, really? My first thought was that it was time to check in with the rain trackers.
"In California for so many years, we could count on no rain from May to October. But this year it rained measurably in June," says Lynn Trowbridge. She has lived in Orinda since the mid-1970's and started tracking the rainfall in her Sleepy Hollow neighborhood almost twenty years ago. "I was just curious," says Trowbridge," I wondered about the intensity of the rains and the impact. We live in an area where four inches of rain in four hours can make a real difference." Trowbridge tracked the daily rainfall with a plastic gauge for years and now uses a self-emptying automated gauge. She reads the rainfall measurements each morning around 7:00 a.m. as she stands warm and dry in her kitchen. [see chart on page D4]
Susan Watson has been following rainfall for over three decades from her house half way up a ridge on the south side of Orinda. She started tracking the rain after severe droughts hit the Bay Area in the late seventies. "We had as little as 12 to 14 inches of rain and were on very strict water restrictions. I would check the water meter constantly to see how much we had to use," says Watson. The marks on her 8-inch plastic gauge have worn away from exposure over the years, but she can still record daily rainfall down to .05 inches. Watson filled several stenographer's notebooks with her rain measurements but has since switched to a computerized record.
"We're not meteorologists. We're amateur rain collectors," says Allan Prager, who keeps his meticulous daily rain measurements on the refrigerator in his kitchen under a magnet that says Save Water. His cone-shaped, plastic gauge is attached to the railing of the deck outside the kitchen on the second story. Prager also lives in Sleepy Hollow but in a forested pocket several hundred feet below his neighbor Trowbridge who resides up on the ridge.
Trowbridge, Watson, and Prager are rain trackers. While they are quick to point out that their rain data are not official and may lack some precision, the three precipitation watchers have a pretty good handle on the local rainfall picture. Prager compiled his twenty years of data with the data from Trowbridge and Watson and compared it to rainfall records from East Bay Municipal Utility District, which has a gauge at the Orinda filter plant. [see chart] The data track closely, but there are some differences. And the rain trackers acknowledge that their rain experiences vary by location, Watson finds that the rain patterns by her home in south Orinda are more affected by the weather in Moraga. And although Prager and Trowbridge live in the same neighborhood, they have observed variations in both rain and temperature. "Oh yes," says Trowbridge, "It's much colder down where Allan lives."
Why do they do it? "We are interested observers," says Trowbridge, "What I really look at is the average rainfall figure. When it's cloudy out a lot, it can be misleading," she says. "And there's so much variability," adds Prager, "I like to follow what month it rains and how much." And all three agree that when a lot of rain falls in Orinda in a short period of time, problems arise. "I want to know if there is going to be a slide in the neighborhood," says Watson. "Rainfall impacts how you manage properties in Orinda. The houses sit on hills, in valleys, and many are heavily populated with trees."
How do they do it? A rain tracker must be observant, curious by nature, interested in her surroundings, and compulsive-or at the minimum quite diligent. S/he must keep the rain gauge level and in an open area without any overhang from the building, trees, or other foliage and remember to take measurements daily. And it helps to know the rainfall lingo: meniscus (measure from the bottom), trace precipitation, fog drip, storm cells, etc., and that the standard rainfall calendar runs from July 1st to June 30th. When the neighbors call... Rain trackers routinely gets calls asking about weather and outdoor plans. They ask me, "Is October safe?" says Trowbridge. When her daughter planned her wedding in late May three years ago, Trowbridge thought it was a pretty safe bet. "Turned out it rained in the morning, but fortunately it stopped," she says. When Prager's daughter chose an early September wedding date with an outdoor reception, he checked the rain records and felt pretty confident that they would stay dry. His prediction held. But who knows, as the rain trackers say, there is so much variability.
So will it be a rainy year? "There is no way you can know in December if it's going to be a dry or wet year," says Prager. He has analyzed how much rain falls in the area by late December, based on his data over the last twenty year. Early rainfall ranges from as little as three inches by December to as much as 20 inches and can represent anywhere from 15% to 52% of the year's total rainfall. [See a summary table of his rainfall data] So whether it will be a wet winter will require you to wait and see.
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Calling all rain trackers: If you have been
tracking the local rainfall patterns, we want
to hear from you. Tell us about it at
storydesk@lamorindaweekly.com.
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Related
Contra Costa County's Rain Gauge with daily rainfall measurements from Orinda (fire station 43) and Moraga (SMC) and cumulative annual data
http://www.co.contra-costa.ca.us/index.aspx?NID=1455
EBMUD's Daily Water Supply Report with daily, monthy,and seasonal data: http://www.ebmud.com/daily-water-supply-report
The Cutting Edge Use of Water Use and Reuse (in Lamorinda): https://www.lamorindaweekly.com/archive/issue0507/The-Cutting-Edge-of-Water-Use-and-Reuse.html
Orinda Can See the Forest for the Trees-another story with Allan Prager: http://www.lamorindaweekly.com/archive/issue0324/Orinda-Can-See-the-Forest-for-the-Trees.html
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Lamorinda Weekly, Moraga CA