First, that fabulous “We’re NASA and we know it” satirical music video commemorating Mohawk Guy and the successful landing of the Curiosity:

I know it’s a satire but still, I’m glad somebody made it.  NASA should be proud of themselves.  Go Curiosity!

On a more local note, I went for a walk along the river that runs through the middle of town this morning with my sister-in-law-in-law (hubster’s brother’s wife), Rachael Paschal Osborn, a public interest water lawyer and a champion of rivers and aquifers everywhere.  Her work deserves it’s own blog post…or more like a book, actually…but suffice it to say for now that she’s  “provided representation to Indian tribes, environmental organizations, labor unions, and small communities since 1992.” Center for Environmental Law and Policy (CELP).

(For anyone interested, here’s an historical blip about some of John and Rachael’s work over the years.  The whole family is like that btw…smart, fearless, idealistic, with jaws that lock…only each to their own area of interest.  Needless to say I had to grow a backbone in the early years to survive Christmas.)

Anyway, she came to town for yesterday’s water conference on the Boise River and she shared a few things with me this morning that are pertinent for local residents but may also prove interesting to anyone that lives near an actively managed river.

First, a little history recap of our dams and local flooding prospects:

The Boise River runs beside or through a series of municipalities including Boise, Garden City, Eagle, Star, etc. as it flows down the valley to eventually empty into the Snake River.  It’s 102 miles long with a watershed (the land collecting water and feeding it into the river) that covers approximately 4,100 square miles.  That’s a whole lot of land, my friends.

As I’ve mentioned in other posts, three dams were built upstream from Boise over the years: Arrowrock Dam (where we love to kayak) was built in 1915, Anderson Ranch Dam in 1950, and Lucky Peak Dam–the one directly above town that haunts all of our if-it-were-to-ever-break dreams–in 1955.

Now, here’s what I just learned this morning.  The latter two dams (I’m not sure about Arrowrock) were built by congressional decree and I always assumed it was primarily for flood control.  You know, to protect the cities that lay downriver from being inundated during catastrophic spring run-offs.  And as an additional side benefit, they could also supply a regulated flow of water into the widespread matrix of irrigation canals that supply the large agricultural industry that exists here in the Treasure Valley.

Well, turns out I had it backwards.  Flood control is not the primary purpose of our dams.  Irrigation is.  Which means that the dams’ water management policies are skewed a whopping 90% in favor of agricultural interests and a piddly 10% in favor of flood management.

In other words, farmers and the companies that own the irrigation canals have the last say, and as long as their homes aren’t flooding, they’ll be more concerned about getting plenty of water to their fields than about whether the city is underwater or not.  Water managers are legally required to maintain a minimum water level in the dams at all times for irrigation use.  Their hands are tied.  They can’t release any extra no matter what, even to make room for an unusually large snowpack or potentially catastrophic spring river flows.

Up until now, that hasn’t really been a problem.  Historically, winter snow, spring rain, and temperatures have been fairly predictable and cooperative.  The term “hundred year flood” was accurately coined back in the old days to describe the kind of whopper that only happened once in a hundred years.  Otherwise?  The water funneling down on us from across the length and breath of those 4100 miles has always been manageable.

Historically.

And there’s the rub.  Historical models are starting to break down.  Our weather, precipitation, and temperatures have been getting increasingly wonky of late and our water managers are growing correspondingly uneasy.  Take the spring flooding that happened this year for instance.

Snowfall was cooperative.  The winter storms were later than usual but by March we’d still managed to accumulate a decent snowpack in the average range.

Snowfall: Check.

Then came an unusually warm April with a couple days of temperatures that soared up into the 80’s–near record setting but not unprecedented.  As a result all that glorious snowpack started to melt at a rapid clip but confidence was still high that enough water could be released from the dams to meet the minimum irrigation requirements and still make room for the rising water flows.

Temperatures:  Check.

But then came that unexpected deluge.

Rainfall:  Huh-oh.

Two and a half inches in April–double the average–with a record breaking one and a half inches of it falling in a 24 hour period.

(Now I know some who hail from lush, green places are scratching their heads and saying “Huh?  We get an inch and a half in an HOUR sometimes.  So what?”   To understand the difference, get two big pitchers and fill them with water.  Take one outside and pour it on your grass.  That’s what happens where you live.  Then take the other pitcher and pour it on your desk.  That’s what happens here.  It’s about absorption.)

The torrential rain fell on an already warmed and melting snowpack and as a result, the creeks and streams feeding into the Boise River went ballistic.  The amount of water flowing into the dams surged and the water managers, who’d been maintaining the required minimum level of water for irrigation, suddenly didn’t have enough room for it all.  They found themselves in the historically unlikely position of having to open the stops and let her rip, those downstream be damned.

They deployed the spectacular rooster tail among other strategies.  The scale doesn’t come across in the video btw.  This thing is massive, like a major waterfall running sideways.

 

video by Rangewriter (she’s got a blog post about the rooster tail at the link for anyone interested.)

Needless to say there was some collateral damage in the municipalities downstream but luckily, it wasn’t nearly as bad as it could have been.  This year anyway, the water managers were able to walk a razor’s edge between releasing just enough water to protect the dam while inflicting the least amount of harm possible on the cities below.  There was some flooding, an overwhelmed canal, a lot of groundwater seepage into basements and crawl spaces, and several stretches of the greenbelt were submerged for a while,  but for the most part it was just chalked up to an unusual year by the unsuspecting populace.

Most people didn’t realize we dodged a bullet.

But according to Rachael, for the water managers, it was a wake up call.  She said one of them mentioned that out of all the dams he’d ever managed (the Grand Coulee dam among them) we’re the least prepared here for any deviation from historical weather norms he’s ever seen, due in large part to the fact that irrigation interests have such a stranglehold on water management policy.

Just thought you might like to know.

And now for the fun part.  You want to see how your own, particular home or business might be affected by a major flooding event in Boise?  Want to see how high the river has to be running before it starts lapping at your door?

Well NOAA has developed just the online toy for you.  Here’s an interactive map which charts how far the river would spread at higher and higher rates of water flow.  It’s among the first of it’s kind (here’s a link to an Idaho Statesman article explaining how and why it was developed and who paid for it) and you can use it to see at what stage places like the  zoo, the football stadium, and the parks would all go underwater.

(Unfortunately, the map doesn’t stretch downriver quite far enough to pinpoint when our house would submerge though.  Bummer.)

I’d encourage everyone living anywhere near the river to check it out.  I don’t see the broader politics of water management policy in our area changing anytime soon so it might be wise to make emergency plans on an individual basis instead.  In case the historical norms aren’t normal anymore.

copyright Dia Osborn 2012