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Arthur Johnson

Publications and source records attributed to Arthur Johnson.

17 recordsLinked to original sources
USGS1980

Grinnell and Sperry Glaciers, Glacier National Park, Montana: A record of vanishing ice

Grinnell and Sperry Glaciers, in Glacier National Park, Mont., have both shrunk considerably since their discovery in 1887 and 1895, respectively. This shrinkage, a reflection of climatic conditions, is evident when photographs taken at the time of discovery are compared with later photographs. Annual precipitation and terminus-recession measurements, together with detailed systematic topographic mapping since 1900, clearly record the changes in the character and size of these glaciers. Grinnell Glacier decreased in area from 530 acres in 1900 to 315 acres in 1960 and to 298 acres in 1966. Between 1937 and 1969 the terminus receded nearly 1,200 feet. Periodic profile measurements indicate that in 1969 the surface over the main part of the glacier was 25-30 feet lower than in 1950. Observations from 1947 to 1969 indicate annual northeastward movement ranging from 32 to 52 feet and generally averaging 35-45 feet. The annual runoff at the glacier is estimated to be 150 inches, of which approximately 6 inches represents reduction in glacier volume. The average annual runoff at a gaging station on Grinnell Creek 1.5 miles downvalley from the glacier for the 20-year period, 1949-69, was 100 inches. The average annual precipitation over the glacier was probably 120-150 inches. Sperry Glacier occupied 800 acres in 1901; by 1960 it covered only 287 acres, much of its upper part having disappeared from the enclosing cirque. From 1938 to 1969 certain segments of the terminus receded more than 1,000 feet. Profile measurements dating from 1949 indicate a lowering of the glacier surface below an altitude of 7,500 feet, but a fairly constant or slightly increased elevation of the surface above an altitude of 7,500 feet. Along one segment of the 1969 terminus the ice had been more than 100 feet thick in 1950. According to observations during 1949-69, average annual downslope movement was less than 15 feet per year in the central part of the glacier and slightly more rapid toward the edges and at higher parts on the glacier.

Montana↗
USGS1962

Glacier observations, Glacier National Park, Montana, 1961

This report records the results obtained during the 1961 season in the continuing program of glacier observations in Glacier National Park. The investigations currently in progress relate to the Grinnell and Sperry Glaciers. This program is carried on cooperatively by the Geological Survey, the National Park Service and the Weather Bureau. The program includes the determination of annual changes in the surface elevation of the glaciers by the measurement of profiles, and changes during the summer months by the establishment of and observations at ablation stakes; rapping the glacier termini in selected years to record advance or recession; determination of annual movement by the location of marked rocks; the operation of two storage-precipitation gages in the immediate vicinity of the Grinnell Glacier to record annual precipitation; the operation of two gaging stations, one just below the Grinnell Glacier during the summer months and one Just below the outlet of Grinnell Lake on a year round basis; temperature data near the Grinnell Glacier and temperature and precipitation data at the Sperry Chalet near the Sperry Glacier during the summer months. The results of the work are described in the following sections.

Montana↗
USGS1955

Preliminary report on the potential waterpower of Grant, Ptarmigan, Cooper and Crescent lakes on the Kenai Peninsula, near Seward, Alaska

Grant, Ptarmigan, Cooper, and Crescent Lakes, located in the Kenai Mountains in the upper portion of the Kenai River Basin, approximately 25 miles to the north of Seward, present favorable opportunities for the development of waterpower. Grant and Ptarmigan Lakes can be made readily accessible by roads from the Seward-Anchorage Highway which in this area practically parallels the Alaska Railroad; and Cooper and Crescent Lakes by access roads from the Sterling Highway. Geologic conditions are favorable for the construction of the various elements of a power development although some special problems may be encountered. The power sites are located in areas of severe winter temperatures, -30° to -40° or less in most winters. This climatic feature must be given due consideration in the design of the various structures required for a power development. Streamflow records are available for a 7-year period for Grant and Ptarmigan Creeks and for a 5-year period for Cooper and Crescent Creeks. Only short and incomplete records of precipitation are available in the area of the power sites but records have been kept at Seward for 30 years. The precipitation at Seward during the periods for which streamflow records are available was, in general, less than average. It seems reasonable that similar conditions would prevail over the upper Kenai Basin. Consequently, the available stream-flow records cover a period of less than average precipitation and estimates of potential power based on these figures probably are on the conservative side. Only regulated flow is considered in this report. Each of the four lakes is a favorable storage site. Adequate capacity for complete regulation of the flow on a year-to-year basis or over a period of several years can be obtained by the construction of dams ranging in height from 20 to 50 feet. Water from the reservoirs can be conveyed to the powerhouses through conduits, tunnels, or pipelines of reasonable length. The total estimated potential power for the four lakes is 11,000 kilowatts for 90 percent of the time and 14,000 kilowatts for 50 percent of the time. Transmission line distances to Seward range from 22 miles for the Ptarmigan Lake power site to as much as 50 miles for the Cooper Lake power site that would be located on the Kenai River. The transmission line distance to Anchorage will approximate 100 miles, depending on the route selected.

Alaska↗
USGS1950

Reconnaissance of Lake Chackachamna, Alaska

The purpose of this brief investigation was to obtain general information on Lake Chackachamna and its water-power possibilities which would serve as a guide in planning and executing future studies. Field investigation consisted of a flight to the lake in a small float plane (see Plate I-B) by the writer on August 3, 1948, landing on the lake near the outlet, making a brief study of conditions there and taking a number of pictures of which several are included in this report with appropriate descriptions. The flight was made with Jack Carr of Anchorage from whom the plane was chartered. It was rather windy at time of landing on the lake and as the wind velocity was increasing Mr. Carr recommended that the stay there be made as short as possible and was consequently less than an hour.

Alaska↗