Introduction
The writers were members of a five-man party employed by Metcalf and Eddy, Engineers, Boston, Massachusetts, who were under contract with the U.S. Navy to make a study concerning the feasibility of constructing a land-based airfield in the Marble Point-Gneiss Point area on the western shore of McMurdo Sound, AntarcticaFootnote † The field work was carried out between 13 December 1957 and 14. February 1958. The quantity of melt water for two streams was roughly determined because of its importance in drainage and domestic water supply, and because of the possibility that water would be needed for construction if an ice fill proved feasible.
Description of Area
The area is bounded on the east and north by McMurdo Sound, on the west by Wilson Piedmont Glacier and on the south by the eastern shoulder of Hogback Mountain. Four major melt-water streams are found here. They are, from south to north, the South, Ball, Surko and Scheuren Rivers (Fig. 1). The Surko and Scheuren Rivers originate in the Davis Lakes, shallow moraine-dammed lakes located near the terminus of the glacier (Fig. 2). Only the Surko and Scheuren Rivers were studied.
Map showing the Marble Point–Gneiss Paint area. McMurdo Sound, Antarctica
A vertical aerial photograph showing Wilson Piedmont Glacier, snowdrift-ice slabs, the Davis Lakes and the Surko River
Meteorology
In the interval from 19 December 1957 to 13 February 1958, the highest air temperature at Marble Point was 5·6°C and the daily maximum air temperature was at or above 0°C for 45 days. In the interval from 2 January 1958 to 13 February 1958, the highest average daily soil temperature 2·5 cm below the surface was 11. 1°C and the average daily soil temperature 2·5 cm below the surface was at or above 0°C for at least 34 days (Fig. 3).
Daily maximum and minimum air temperatures, daily average soil temperatures and cloud cover during the 1957–58 summer season at Marble Point, McMurdo Sound, Antarctica
In the interval from 14. November 1958 to 25 January 1959, the highest air temperature at Marble Point was 5·17°C and the highest soil temperature 2·5 cm below the surface was 20·56°C (Reference Nichols and BallNichols and Ball, 1964[b], p. 358). Extrapolating from the data, it seems likely that between 1 November 1958 and t November 1959 the daily maximum air temperature was above 0°C for perhaps 39 days and the daily maximum soil temperature 2·5 cm below the surface was above 0°C for more than 63 days.
A comparison of the data for air temperature and cloud cover shows that when the cloud cover is absent or scattered the air temperature is high and when it is continuous and dense the air temperature is low (Fig. 3). The air and soil temperatures also correlate reasonably well. With these air and soil temperatures it is not surprising that sizable melt-water streams are found in the summer months in the Marble Point–Gneiss Point area and that alluvial fans, valley trains, marine and lacustrine deltas, kame moraines, hillocks, and ridges, torrential fluvial boulder deposits, thaw channels in ice, marginal channels and ravines cut in surficial deposits are common in this part of Antarctica (Reference Nichols and TedrowNichols, 1967, p. 33–34)
Melt-water Sources
The main source of the melt water is Wilson Piedmont Glacier and the snowdrift-ice slabs are next in importance (Fig. 4) (Reference NicholsNichols, 1964). Wilson Piedmont Glacier terminates in places in a ramp and in other places in an ice cliff. Small melt-water streams run down the ramp during the warm season and small melt-water waterfalls are found along the ice cliff. No water issues from the bottom of the glacier, however, because the mean annual sea-level air temperature is not far from −20·0°C (Reference Nichols and BallNichols and Ball, 1964[a], p. 355). Small slushers commonly slide down the ramps during the warmest days of summer. They form small snow fans at the edge of the glacier and they remove melt water from it.
A snowdrift-ice slab adjacent to Wilson Piedmont Glacier approximately 3·5 km west of Marble Point
The seasonal snowfall is not an important source of melt water. The snowfall is light and the presence of penitentes, plough-share snow surfaces and sun cups indicates that much of it is dissipated by evaporation (Reference NicholsNichols, 1953, p.135–37). The ice in the active zone is of no importance. No rain has ever been reported in the McMurdo Sound area (Reference SimpsonSimpson, 1919, p. 159); hence all run-off is melt water.
Factors in the Formation of Melt Water
Among the important factors in the formation of melt water are: (1) The air temperature, which depends mainly on the height of the sun, the length of the day and the characteristics of the cloud cover. (2) The soil temperature, which depends mainly on the free-air temperature, the albedo and moisture content of the soil, and insolation. (3) The presence or absence of debris on snow and ice. (4) The surface gradients of the glaciers, as these gradients determine the areas of snow and ice in the zone where melting can occur, as well as the amount of insolation. (5) The orientation of the snow and ice slopes. In general, in the Southern Hemisphere north-facing slopes receive more insolation than south-facing slopes.
Hydrology
Data were obtained on the melt-water discharge of both the Surko and Scheuren Rivers (Fig. 1). The construction equipment, instruments and manpower for a comprehensive program were not available. However, sufficient measuring devices were installed to obtain a general picture of the seasonal run-off. No measurements were made before 20 December 1957 or after 12 February 1958. Estimates of the run-off for the periods of melt-water flow not covered by measurements were made by extrapolation from the hydrologic data obtained and from an analysis of the available weather records of the area.
Stream gauging was initially limited to the construction of a small rock-fill dam and weir across one of the two channels of the Surko River, and to a few cross-section and velocity measurements made periodically at other locations along both the Surko and Scheuren Rivers. However, after the arrival of the heavy construction equipment a diversion dam was built and the entire flow of the Surko River was made to pass through the weir. Further details on the measurement procedures can be obtained from an unpublished report submitted to the Department of the Navy, Bureau of Yards and Docks, Washington, D.C. (Reference Metcalf and EddyMetcalf and Eddy, unpublished, p. 180–88).
Temperature, Flow Pattern and Quantity of Melt Water
There is a good correlation between air temperature and melt-water temperature. When the air temperature is high the melt-water temperature is high, and when the air temperature is low the melt-water temperature is low (Fig. 5). The average melt-water temperature is at times several degrees warmer than the average air temperature (Fig. 5). At first this seems surprising, especially in view of the fact that the temperature of the melt water was measured only a few hundred meters from Wilson Piedmont Glacier. However, much of the melt water comes from the Davis Lakes, which are shallow. The temperature of one of them in early January was approximately 7°C.
A comparison of air and melt-water temperatures at Marble Point, McMurdo Sound, Antarctica
The maximum discharge of the north branch of the Surko River for the 1957–58 season occurred on 22 January 1958 (Fig. 6). The melt-water flow in general is at a minimum in the early morning (05.00 h) and rises to a maximum in the mid-afternoon (16.00 h).
A typical daily flow pattern of the north branch of the Surko River, Marble Point, McMurdo Sound, Antarctica
The average daily melt-water discharge for both the Surko and Scheuren Rivers is shown on Figure 7. The maximum average daily melt-water discharge of the Surko River is about 0·39 m3 s−1 (14 ft3 s−1) and the maximum average daily melt-water discharge of the Scheuren River is approximately 0·59 m3 s−1 (22 ft3 s−1) (Fig. 7). There is a good correlation between air temperature and meltwater discharge (Figs. 5 and 7).
The average daily melt-water discharge of the Surko and Scheuren Rivers, Marble Point, McMurdo Sound, .Antarclica
The seasonal discharge for the Surko River is estimated to be approximately 13 m3 s−1 d (470 ft3; s−1 d), and for the Scheuren River approximately 19 m3 s−1 d (670 ft3 s−1 d) (Fig. 8). The combined seasonal discharge of both rivers is approximately 32 m3 s−1 d (1 140 ft3 s−1 d). It seems likely that the total discharge of all the major melt-water streams of the Marble Point-Gneiss Point area for the 1957–58 melt season was not far from 50 m3 s−1 d (t 800 ft3 s−1 d). The average yearly discharge is unknown, as almost nothing is known of the meteorology of the area.
The seasonal discharge of the Surko and Schrurera Rivers, Marble Point, McMurdo Sound, Antarctica
The glacial front which contributes melt water to the Surko River is approximately 8300 ft (2530 m) long. The snowdrift-ice slab found in the drainage basin of the Surko River also contributes significantly to the run-off. The Scheuren River is fed by only 6 300 ft (1920 m) of the front of the glacier. It seems likely that the Scheuren River receives more melt water from a shorter distance along the front of the glacier because here the glacier slopes more to the north (Fig. 1).
Acknowledgements
Data were provided by the Commanding Officer, U.S. Naval Construction Battalion Reconnaissance Unit. The writers are happy to acknowledge the help they received from Commander Henry C. Stephens, U.S.N., and from Messrs Donald G. Ball and J. J. Scheuren. Jr., both of Metcalf and Eddy, Engineers, Boston, Massachusetts, U.S.A.
