“If you are reading this sign, chances are it’s not raining,
and Petaluma Creek is not streaming around your ankles.” They were right. It
was cold, but the beet-red sun was inching up into a clear sky, and it had been
nearly a month since Petaluma Creek spread itself across the flood plain here.
I was standing in the new Denman Reach Flood Terrace Park just upstream from
Corona Road. Before me was a block-long shelf of open land fronting the creek. A long low levee, topped by a wide path, separated
the terrace from Industrial Avenue. The idea here, explained the sign, was to
allow flood water a safe place to spread out rather than gouge the creek
channel as it barreled downstream, or spread into someone’s home or business. When
the waters recede to their channel, the terrace becomes a riverside park (Raymond
Jax, *here’s* the place for your music festival!)
Terraces are an increasingly popular flood control technique.
It’s a shame that we didn’t use them, along with downsized development, 60
years ago in the Payran neighborhood, or 20 years ago
along the outlet and auto malls. Councilman Mike O’Brien argued that the
December 31 storm conditions were so unusual that attempting to mitigate them
now, especially by restricting development, is like planning for helicopters
falling out of the sky.
Mr. O’Brien ought to know there are laws of physics (and
Murphy) at work here that should lead the prudent person to avoid certain
behaviors. I was backpacking with a buddy in the Sierras once; having ascended
to the lip of a hanging glacial valley, we pitched our little tent in a sandy area
close to a spectacular vista point. Not exactly high ground --there were safer
sites a bit up the canyon-- but we were very tired, and liked the view. No way
*this* could ever flood, we thought. Well, it rained all night and when day broke we heard a loud gurgling; the floor of our
tent jiggled like a waterbed. We looked outside, and saw that our convenient
campsite was now, in fact, a streambed. By the time we started our 20 mile
evacuation, everything was heavily soaked. Lesson: water takes the lowest path; stay well
out of its way, or pay.
While running errands on New Years Eve morning, we got a
good look at the Petaluma River. Many of the letter streets east of 1st
Street had disappeared into the flood. Milk chocolate rapids churned just few
feet below the new Water Street promenade. Looking across the standing waves at
the Petaluma Village, it was clear our outlet mall needed a better outlet.
Later I checked the aerial photos on City’s website, especially the pictures around
the flood control weir. Hmmm…was our flood fix a floodwater whack-a-mole effort,
hit it here and it pops up there? I’m not going to second-guess the City’s
pending investigation, but consider this: when we walled off the Payran neighborhood, we lost an awfully large (and largely
awful) detention basin. Where did *that* water go? If we channelize
the creek all the way back up to the Pumpkin Patch, storm water won’t back up
in the sky – it will rush and rise into downtown.
I don’t know what the cure is, but some things seem obvious.
The proposed Rainier crossing and the development that might
accompany it… what would the flooding have done to that? What would it
have done to the flooding? Upstream detention basins and terraces seem
promising, on one condition: if the City buys the waterlogged pumpkin patch or
any of the Chelsea expansion parcels, we had better not pay an inflated,
pre-flood development value.
Flooding is a fascinating wild phenomenon when viewed from
high ground. But having many times evacuated my mother-in-law from her Russian
Riverfront home, and twice cleaned up the muddy mess afterwards, I’m familiar
with the tragedy of floods. Our ignorance and folly only compound the problem.
Will we humans continue to cook up extreme weather and rising tides, and still
build along the water’s edge? We’ve made enough mistakes already. Let’s not
make any more.