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| The Nov 22nd and Dec 14th peak flows on San Geronimo Creek were the same: 1,105 cfs. Daily average flows were 423 cfs & 356 cfs, respectively. In November it took 8.75 hrs of 2.34" of rain (1/4" per hour) to get to peak from 113 cfs; In December it took 7.25 hrs of 2.32" of rain (1/3" per hour). These calculations use rounded times to the nearest hour for rain and quarter hour for flow & add an hour of lag time between rain and flow. |
"They turned it into Muir Woods," I heard someone say as I was leaving Roy's Redwoods yesterday. Roy's Redwoods is San Geronimo Valley's busiest and most famous local redwood grove. There grows the tallest tree in Marin County.
I had heard this criticism of the $3.5 million Roy's Redwoods rehabilitation project before. The Marin County Open Space District site was closed all summer and completely redone. It is nice to be able to go back this fall and see what it looks like.
The goal of the project was to "
When something like this happens, it is like gentrification of the woods. The "new" Roy's Redwoods looks nice--nice trails, well-organized, nice stone work (although the large boulders are a bit out of place and seem to belong in the Sierra Nevada), nice new boardwalks and bridges. It is welcoming in a familiar National Park sort of way, and makes walking the trails pleasant and efficient. I really like the nested loops of the named trails--once you figure out that pattern it is fairly easy to remember where the trails go. The Wilderness Way exploration and adventure zone is a nice (and surprisingly hazardous, and a totally fun mud pit when rainy) touch.
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| Nice new bridges |
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| Wilderness Way adventure area |
The November 20-22, 2024 Atmospheric River dropped 11.65" in San Geronimo Valley compared to much higher amounts to the north. It was not as wet as the October 2021 storm (that dropped 12.67" in 36 hours causing San Geronimo Creek to peak over twice as high). But the 2024 storm lasted longer--it rained for three days straight (except for a break during the second night). It was so nice to see the sun again on the bright yellow fall leaves on Saturday! San Geronimo Creek peaked at 1,105 cfs at 2:15 pm on Friday November 22nd (at day 3 hour 14 on the graph below). The creek started at its late summer-fall baseflow of less than 1 cfs at the Lagunitas gauge, and as of December 1st is still flowing at 7 cfs. The peak flow was similar in magnitude to last winter season's highest flow in January. We already have about a third of our annual average rainfall as of the end of November, and our 3rd-highest to-date total since water year 2012. Along with over an inch of rain in early November, this has been a wonderful start to our rainy season.
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| Barnabe and Woodacre rain are reported about 10 minutes before and after the hour, respectively, but shown on the hour here (the hourly differences are mostly due to that). The x-axis is day.hour. |
