ill., maps; Includes bibliographical references;
WATER-RESOURCES APPRAISAL OF CRATER LAKE NATIONAL PARK, OREGON By F. J. Frank and A. B. Harris ABSTRACT Crater Lake National Park is on the crest of the Cascade Range in southwestern Oregon. Except for small areas of glacial deposits, the area is underlain by volcanic rocks of Tertiary and Quaternary age. The principal rock types are andesitic and basaltic lavas, pumiceous volcanic flow breccias, tuffs, and airborne and flow pumice. The pumice is an excellent medium for the infiltration of much of the 67 inches of annual precipitation. The pumice and underlying lava flows and pyro-clastic material transmit a large quantity of ground water which percolates to the water table and to various spring outlets. In many areas of the park, the occurrence of perched ground water at altitudes below 6,500 feet is shown by numerous springs that drain water from ground-water bodies perched above the regional water table. Most of the streams and springs in the area flow throughout the year. The quality of the water is excellent. It is soft, has a low mineral content, and contains insignificant amounts of objectionable constituents. During 1962, test drilling in the northern part of the park failed to locate perched-water bodies capable of supplying quantities of water adequate for proposed facilities. However, test drilling indicated that the regional water table is below an altitude of 4,960 feet and that wells at high altitudes may have to be drilled to depths exceeding a thousand feet to obtain water. Because the water table is at undetermined depth and the existence of productive perched ground-water bodies above the regional water table at a specific site cannot be predicted, the possibility of obtaining productive wells in the area is speculative. 1 Springs that have proven to be adequate and dependable are the source of water supply for present facilities. The most favorable areas for the development of ground and surface water are in the western, southern, and southeastern parts of the park. These areas have a well-defined surface-drainage system and have many springs and streams at altitudes below 6,500 feet which discharge quantities of water adequate for additional park facilities. INTRODUCTION Crater Lake National Park is in a scenic mountainous area about 65 miles north of the Oregon-California State line, and its principal attraction is Crater Lake (fig. 1). The popularity and increased use of the park have placed increasing demands on existing camping facilities and have led to the consideration of additional sites for camping and other uses. Therefore, at the request of the National Park Service, the U.S. Geological Survey made a geologic and hydrologic appraisal of potential water supplies for new recreation sites. This report explains the relation of the geologic environment to the occurrence of water. It also describes the hydrologic conditions, chemical quality of the water, and potential water supply of Crater Lake National Park. Fieldwork was done during October 1967 and June and September 1968. Discharge measurements were made of streams and springs, water samples were collected and analyzed for chemical quality, and geologic reconnaissance was made of all major streams and springs. Personnel of the Park Service, under the supervision of Donald M. Spalding, park superintendent, were helpful at all times and gave splendid cooperation, which is gratefully acknowledged. Particular thanks are given to Paul A. Larson, assistant park superintendent, and M. B. Evans, management assistant. The investigation was made under the general supervision of S. F. Kapustka, district chief in charge of water-resources investigations in Oregon, and under the immediate supervision of D. D. Harris, chief of the Hydrologic Investigations Section. GEOGRAPHIC FEATURES Crater Lake National Park is on the crest of the Cascade Range in southwestern Oregon. Altitudes range from 3,977 feet near Red Blanket Creek at the south park boundary to 8,926 feet atop Mount Scott. The park area is about 250 square miles, and its most prominent feature is Crater Lake, which occupies about 20 square miles. The lake occupies the crater of Mount Mazama, largest of several extinct volcanic cones that dot the park. The rim of the crater ranges in altitude from about 6,700 feet to more than 8,000 feet, and the lake level is about 6,170 feet. The area north of the lake is characterized by broad moderate slopes and flat areas broken by lava and cinder cones and several steep, rocky ridges. Steep-sided Mount Scott and rolling lava terrain with several steep-walled broad canyons are east of the lake. The area south 2
WATER-RESOURCES APPRAISAL OF CRATER LAKE NATIONAL PARK, OREGON By F. J. Frank and A. B. Harris ABSTRACT Crater Lake National Park is on the crest of the Cascade Range in southwestern Oregon. Except for small areas of glacial deposits, the area is underlain by volcanic rocks of Tertiary and Quaternary age. The principal rock types are andesitic and basaltic lavas, pumiceous volcanic flow breccias, tuffs, and airborne and flow pumice. The pumice is an excellent medium for the infiltration of much of the 67 inches of annual precipitation. The pumice and underlying lava flows and pyro-clastic material transmit a large quantity of ground water which percolates to the water table and to various spring outlets. In many areas of the park, the occurrence of perched ground water at altitudes below 6,500 feet is shown by numerous springs that drain water from ground-water bodies perched above the regional water table. Most of the streams and springs in the area flow throughout the year. The quality of the water is excellent. It is soft, has a low mineral content, and contains insignificant amounts of objectionable constituents. During 1962, test drilling in the northern part of the park failed to locate perched-water bodies capable of supplying quantities of water adequate for proposed facilities. However, test drilling indicated that the regional water table is below an altitude of 4,960 feet and that wells at high altitudes may have to be drilled to depths exceeding a thousand feet to obtain water. Because the water table is at undetermined depth and the existence of productive perched ground-water bodies above the regional water table at a specific site cannot be predicted, the possibility of obtaining productive wells in the area is speculative. 1 Springs that have proven to be adequate and dependable are the source of water supply for present facilities. The most favorable areas for the development of ground and surface water are in the western, southern, and southeastern parts of the park. These areas have a well-defined surface-drainage system and have many springs and streams at altitudes below 6,500 feet which discharge quantities of water adequate for additional park facilities. INTRODUCTION Crater Lake National Park is in a scenic mountainous area about 65 miles north of the Oregon-California State line, and its principal attraction is Crater Lake (fig. 1). The popularity and increased use of the park have placed increasing demands on existing camping facilities and have led to the consideration of additional sites for camping and other uses. Therefore, at the request of the National Park Service, the U.S. Geological Survey made a geologic and hydrologic appraisal of potential water supplies for new recreation sites. This report explains the relation of the geologic environment to the occurrence of water. It also describes the hydrologic conditions, chemical quality of the water, and potential water supply of Crater Lake National Park. Fieldwork was done during October 1967 and June and September 1968. Discharge measurements were made of streams and springs, water samples were collected and analyzed for chemical quality, and geologic reconnaissance was made of all major streams and springs. Personnel of the Park Service, under the supervision of Donald M. Spalding, park superintendent, were helpful at all times and gave splendid cooperation, which is gratefully acknowledged. Particular thanks are given to Paul A. Larson, assistant park superintendent, and M. B. Evans, management assistant. The investigation was made under the general supervision of S. F. Kapustka, district chief in charge of water-resources investigations in Oregon, and under the immediate supervision of D. D. Harris, chief of the Hydrologic Investigations Section. GEOGRAPHIC FEATURES Crater Lake National Park is on the crest of the Cascade Range in southwestern Oregon. Altitudes range from 3,977 feet near Red Blanket Creek at the south park boundary to 8,926 feet atop Mount Scott. The park area is about 250 square miles, and its most prominent feature is Crater Lake, which occupies about 20 square miles. The lake occupies the crater of Mount Mazama, largest of several extinct volcanic cones that dot the park. The rim of the crater ranges in altitude from about 6,700 feet to more than 8,000 feet, and the lake level is about 6,170 feet. The area north of the lake is characterized by broad moderate slopes and flat areas broken by lava and cinder cones and several steep, rocky ridges. Steep-sided Mount Scott and rolling lava terrain with several steep-walled broad canyons are east of the lake. The area south 2