For the past few weeks, the stream team has been busy taking last minute water samples, making final gauge visits, and collecting algae. Several streams will continue to flow after we leave, so we have left the instrumentation running in the boxes to keep measuring flow just in case. The end of the season is also good for a lot of last minute construction since the ground is still not completely frozen, yet streamflow has slowed if there is still flow at all. Gauges that have been damaged during the flow season are repaired at this time, and new gauges are built either at new sites or to replace those that will be retired.
The last thing we do before we leave the Dry Valleys for the season is re-survey the streams just like we did at the beginning of the year. We also measure any changes in the levels of the lakes scattered all over the Dry Valleys to see if they are increasing, decreasing, or staying the same. Recently, Dry Valley lake levels have raised enough to require the 20-year old stream gauges to be migrated further upstream or abandoned completely. Additionally, some camp structures, sites, and transects have been claimed by the lakes, and will be an obstacle for planners for the next few years. For example, at Lake Hoare and Lake Bonney, numerous camp structures were moved to higher ground after the lake encroached upon their foundations last year.
Most everything we have at our camps goes back to McMurdo by helicopter, including our tents, equipment, and our many samples. Some samples are taken to the Crary Laboratory and analyzed right away on station, while others are shipped back to the United States where we can do the analyses at our respective institutions. When all the work in McMurdo is done, we pack up our stuff, and step back onto the sea ice where there is an enormous C-17 waiting to take us back to New Zealand, where we will smell grass, experience darkness, and see dogs for the first time in almost 4 months.