Geology topics
Research about Petersburg, Alaska
Source-linked reports with geographic coverage including Petersburg, Alaska.
Upper Triassic volcanogenic Zn-Pb-Ag(-Cu-Au) mineral deposits near Petersburg, Alaska
No abstract available.
Preliminary report on waterpower resources of Cascade Creek, Scenery Creek, and Delta Creek near Petersburg, Alaska
The heavy precipitation and runoff, suitable storage sites near tidewater, and steep stream gradients are favorable to the development of hydroelectric power on the streams considered in this report. A geologic examination of the sites indicates that their development would not be hindered by any unusual geologic conditions. On the basis of the 18 years of available stream-flow records for Cascade Creek, it is estimated that 20,800 kilowatts of power could have been generated continuously on Cascade Creek; 13,300 kilowatts on Scenery Creek, and 7,900 kilowatts on Delta Creek. Conditions for power development on Delta Creek are not as favorable as on Cascade Creek or Scenery Creek in view of the size of the structures required in relation to the potential power. The development of a substantial part of this power would depend upon the creation of new industries as the present power market is very limited. There is a heavy growth of timber near tidewater throughout this part of Alaska, and the utilization of this timber in the manufacture of wood pulp is the most likely industrial possibility. The Cascade Creek, Scenery Creek, and Delta Creek drainage basins are in rugged mountainous terrain. There is little land in the immediate vicinity suitable for the location of industrial developments and the supporting communities, and the power would have to be transmitted to a more favorable area. A considerable area is available near Point Agassiz on Frederick Sound about 10 air-line miles from the mouth of Scenery Creek and 5 airline miles from the mouth of Delta Creek.
Geology of waterpower sites on Scenery Creek, Cascade Creek, and Delta Creek near Petersburg, Alaska
Dam sites were examined at the outlets of Scenery Lake, Swan Lake, and Ruth Lake which are located on Scenery Creek, Cascade Creek, and Delta Creek, respectively. The Scenery Lake dam site is partly in quartz diorite and partly in hornblende plagioclase gneiss. The Swan Lake and Ruth Lake dam sites are in quartz diorite. The bedrock at these dam sites is suitable for the height of dams that would be required to achieve the full development of the potential power of the streams. No appreciable leakage from the reservoirs is anticipated. Tentative tunnel routes for conveying the water from the lakes to powerhouse sites at or near tidewater were examined. The tunnel routes from Scenery Lake and Swan Lake would be in quartz diorite. The tunnel route from Ruth Lake would pass through quartz diorite and diorite gneiss. The geologic examinations described in this report indicate that the development of the potential power of the streams under consideration is feasible as far as geologic conditions are concerned.
Water power resources of Scenery Creek near Petersburg, Alaska
Due to high unit runoff, a good storage site, and a high concentration of fall, Scenery Lake presents a favorable power site. By building a tunnel three miles long from Scenery Grove to tap Scenery Lake at elevation 900 feet and a dam to raise Scenery Lake to elevation 1020 feet, the flow of Scenery Creek can be regulated and 16,000 firm horsepower developed. No stream flow records are available on Scenery Creek but 14 years record of the flow of Cascade Creek, the adjacent drainage on the south, has been used for power estimates. A gaging station was established on Scenery Creek in September 1949, and as records become available the estimates contained in this report will require revision. A geologic examination of the dam site area at the mouth of Scenery Creek and the tunnel location along the south bank from Scenery Cove to Scenery Lake should be made before any further work is done on the project.