Antarctica is a desert–on average, the continent receives about half the precipitation we get in Boulder. The Dry Valleys are… ummm…drier than the Antarctic average. The continent has accumulated a lot of water over millennia, but that water is stored as ice (three quarters of the World’s fresh water is stored in continental ice sheets in Antarctica). During the Austral summer, however, some of that water moves, and in the Dry Valleys that moving water forms streams. When I was in the Valleys in 2003 I left in early December, and saw no hint of liquid water. But, today, we found liquid water at C1.
We visited three sites today: the Onyx River at Lake Vanda, the Upper Onyx River in the Lower Wright Valley (hmmmmm) and the Commonwealth Stream. The Wright Valley is one of the most beautiful and interesting places on Earth. At the west head of the Valley is the Wright Upper Glacier, plunging about 1,500 feet over the Airdevronsix icefall. (It’s easy to remember this name if you keep in mind that it is named after U.S. Navy Air Development Squadron Six, which provided air support for Operation Deep Freeze during 1956-1957.) At the opposite end of the Valley, Lake Brownworth is formed by meltwater from the Wright Lower Glacier. Lake Brownworth is the source of the Onyx River, which flows from the Lower Wright Valley west toward the Upper Wright Valley. What? The Wright Valley is an endorheic region–it is a closed basin with its lowest point in the middle, near Lake Vanda, the terminus of the Onyx River. (The same is true of the Taylor valley, where there are three major endorheic lakes. Don Juan Pond, in the Upper Wright Valley is the saltiest body of water on earth. It actually absorbs moisture from the air under certain conditions. This represents the ultimate endorheic lake.)
First, we opened the Onyx River at Lake Vanda gauge. The panorama at the top is looking downstream toward the Vanda gauge. The gauge box is right of center with the Kiwi hut on the extreme right in the background, all in front of Lake Vanda.
Here I am illustrating one of our reference points, an odd little drywall screw in the staff plate at the Vanda gauge. Note that the staff plate extends to 3.3 feet–the Onyx is a big river. In fact, it is the largest and longest river in Antarctica. If we’re lucky, we’ll see some good flows here in a month or so.
It was cold and breezy out today–we all worked in our “Big Red” parkas. When we fly outside of the Taylor Valley we are required to wear our ECW gear, including the Bunny Boots. Mikey and I got “boot waivers” that allow us to fly to neighboring valleys in our mountain boots, but I misplaced mine. I could work that out, but it doesn’t matter much for those flights, since we don’t walk much when we fly to a site outside the Taylor Valley. (In the Valley we sometimes fly out and walk back.) I was glad to have the bunny boots today–working on the gauges involves a lot of standing around.
After we opened the Onyx at Vanda, we moved to the Upper Onyx at Lower Wright. (We could call that the paradox site, just as the Paradox Valley in Colorado and Utah is so named because the Dolores River cuts across the valley.) The Lower Wright gauge is right below Lake Brownworth, and it has a channel worthy of Colorado or Utah.
The gauge box on the left holds the equipment, which I will describe in a later post. the control is the line of rocks (actually a gabion of chicken wire filled with rock), with the PZF (point of zero flow, or the low spot) in the center. Here’s a closeup of the staff plate.
Like the Lower Onyx at Vanda, this staff can measure 3.3 feet (about a meter) of depth. This river could be kayaked.
But, the action today was at C1, a gauge on the Commonwealth Stream, on the east side of the Commonwealth Glacier. Chris had e-mailed some telemetry data that implied liquid water was present (this gauge, and a few others, send data back to Boulder via a satellite connection). Chris’s data showed subtle diurnal changes (changes occurring in a daily cycle) in conductivity and stage (the depth of water) that made him suspect that the water around the sensors was liquid. When we arrived at C1 that was not apparent, but when we walked down to the stream we broke through a relatively thin skim of ice and found water. This is not a great photo, but here it is.
Speaking of photos, this afternoon I felt like I was paying for some serious sins in a previous life, or perhaps that I had sinned more in this life than I tho had thought–my camera ran out of battery just before we left the Lower Wright site to move to C1. That is a spectacular flight (they all are, honestly) with some beautiful ventifacts. I’ll be more conscientious about charging the camera from now on.