Modeling and Designing Control Flow Systems for Drainage Channels at McMurdo Station, Antarctica

During the Austral summer at McMurdo Station in Antarctica, snowmelt runoff can be very heavy. The runoff passes through McMurdo via a system of drainage ditches, gullies, and culverts. During heavy flow, the runoff mobilizes sediment, erodes the drainage channels and embankments, and overflows onto roads. This problem can be minimized by controlling the flow, e.g., via check dams, wooden weirs, or other methods. Important site properties are the steepness of the terrain and drainage paths and the lack of vegetation. Critical to this study is understanding the flow characteristics in the channels. Based on the flow characteristics taken from 2010-2011 field measurements, flow control modeling was developed for an extreme flow scenario in the McMurdo drainage systems. A one-dimensional hydraulic model was used to estimate the impact of weirs during high flow conditions. Owing to the complex environment at McMurdo, three dam designs are being considered for their portability, durability, and practicality, including ease of installation and removal each season. These flow structures included check dams, a wooden weir, and a commercially produced system to help impound the flow during the extreme runoff event. Both the estimated frictional and horizontal ratio and the bearing capacity ratio of the designed structures are greater than one, a requirement of the design conditions. The modeling and preliminary designs are intended to be part of erosion mitigation at McMurdo Station.