Streaming Flows, Flowing Streams

Commonwealth Stream and Commonwealth Glacier
Canada Stream 11/14/2008 (Left) and Canada Stream 12/08/2008 (Right)

Gauging the Onyx River in the Wright Valley

The temperature has been rising over the past week or so.  At the start of last week, we had clear blue skies and temperatures hovering around 32 degrees.  We saw streams flowing, Huey Creek and Lost Seal Stream, for the first time into Lake Fryxell.  I thought that would be a jump start and all the streams would be flowing.  But a low pressure system moved into the Dry Valleys with clouds and temperatures in the low to mid twenties.  This shut off the faucet, so to speak, and the streams mentioned above weren't flowing at all the next day.  We visited Lake Bonney, which we had seen flow the week before, only to find the same result, no flow.  A short helo ride to Lake Hoare where we spend most of our weekends and gauge two streams.  By Saturday, the sun was shining and the temperatures were rising, a steamy 34 degrees.  Both streams were flowing and we went to work making discharge measurements and collecting water samples.  That is what we will be doing at each stream visit from now until the temperatures drop and streams no longer flow.  

In the Canada Stream photos, you can see the difference in a stream due to rising temperatures as we begin the warmest part of the austral summer.  We will try and visit streams at different times of day/"night" to determine the volume of water moving through the system when the source glaciers are receiving different amounts of sun.  For instance, tonight my team and I will be heading out at 2000 hours (8 p.m.) to a couple of different streams because that is when peak flow is expected.  This will give us a better understanding of how much water is flowing at low flow and peak flow periods.

Today we took a helo flight to the Onyx River in the Wright Valley.  We saw flow here for the first time all season as well.  In the picture, I am making a discharge measurement.  This is found by measuring the width of the stream and taking depth measurements at increments across the stream. This gives you the area of your cross section.  At each increment a water velocity measurement is made.  Multiplying the velocities by the area will calculate a discharge measurement, which is reported in cubic feet per second.  The measurement and sampling is only half the fun, the other part is the trips to and from the locations.