Rivers

My new home and office sit in the bottom of the Upper Middle Fork of the San Joaquin River Valley, or the UMFSJRV, if you like.  I arrived early enough this year to witness the peak flow pulse, caused by melting snow thousands of feet up the valley:

One component of our climate change research is detecting changes in flow and timing of snowmelt pulses in the river.  Across the West, the timing of peak stream flow in snowmelt-driven rivers is occurring earlier and earlier into the spring and appears to be correlated with rising temperatures.  What’s left to discern is whether this change is due to natural variability or human actions.  So, when word came through that a snowmelt surge was imminent in the San Joaquin we called in a crew from Yosemite to help us quantify the pulse.  Their machine utilizes acoustic doppler  to map the profile of the river bottom and also measures the velocity of individual water molecules to calculate discharge.

What sounds like a technical or challenging task in this job, however, is ultimately another opportunity to enjoy being outdoors:

I was also thrilled to operate a piece of equipment that comes with a $30,000 price tag:

Of course, rivers aren’t just meant to be studied.  They’re meant to be enjoyed during sweltering, all day bike rides through the mountains:

And the bike riding has been exceptional lately, as evidenced by the smiles:

and the destinations of rides lately:

But, back to the San Joaquin valley.  The cool thing about my new home, I’ve discovered, is all the stories that are written in the rock, waiting for someone to come along and read them.  There are stories of lava rivers flowing down valley, mountains rising and eroding, magma chambers building below the earth, and of glaciers advancing and retreating.  It’s all basically introductory geology subject material but when you see the products of those events right in front of you it quickly captures your imagination.

Some of my more recent encounters with these clues of the geologic past include this glacial erratic, carried miles away from where it originated and plopped down amongst foreign rock when the glacier melted:

and clutching this chunk of granite that began its life as a swirling, molten pool of magma that formed miles below the Earth’s surface:

Essentially, wherever you go the eastern Sierra has stories to tell and I’m definitely not done reading them.

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