Manual lake level measurements are made with a survey rod, tripod, and autolevel. Generally one measurement is taken in the early austral summer (Oct/Nov), and a second measurement towards the middle/end of the austral summer (Jan/Feb). The MCM LTER has made an attempt to reference all of our observations to the historical (and published) record from the dry valleys. That means that while the values in meters above sea level are correct with respect to the old KIWI data, they will not match differential GPS measurements made without correcting to the KIWI datum.
During MCM-I, new lake leveling benchmarks were established at the three main Taylor Valley camps for ease of measurement. Each of these new benchmarks was measured using differential GPS to a high degree of accuracy. To put lake levels in the context of the historical data, a similar GPS survey was carried out on old Kiwi benchmarks that have been used for leveling in the past, and an offset applied to the data collected from the new benchmarks.
See the following PDF files for photographs of the Dry Valleys Lake Level benchmarks: