From purpose and scope: This report describes methods for estimating the magnitude and frequency of floods at ungaged sites on streams with unregulated flow in eastern Oregon. The purpose is to provide a method to estimate flood magnitude and frequency and to present the supporting data. The report is based on data from nearly all unregulated streams (or data from regulated streams prior to their regulation) where gaging stations have been operated.

From introduction: The purpose of this report is to provide sufficient geologic and hydrologic data to aid in the future development of ground- and surface-water supplies. The objectives were to determine the availability, quantity, and quality of ground- and surface-water supplies with reference to problems of development, and to determine the limitations of the water resources.

Abstract: The various components of inflow and outflow to and from the lake and their relative magnitudes were identified. In 1972 water year the total inflow to the lake was 200,000 acre-feet, but it was only 75,000 acre-feet in 1973 water year. In 1972 water year the Donner and Blitzen River contributed 55 percent of the inflow, with Silvies River, direct precipitation, and Sodhouse Spring contributing 28, 13, and 4 percent respectively. Om 1973 the Donner and Blitzen River contributed 61 percent of the inflow. The Silvies River, direct precipitation, and Sodhouse Spring contributed 1, 25, and 12 percent respectively. Ground-water inflow, other than Sodhouse Spring, appears to be negligible. In 1972 water year, 81 percent of the outflow was by evapotranspiration and 19 percent was surface outflow through The Narrows. In 1973, 96 percent of the outflow was by evapotranspiration and 4 percent was surface outflow through The Narrows. Ground-water outflow is negligible.

From introduction: Of the various hydrologic hazards in our environment, the mass movement of earth material caused by excess moisture can be one of the most destructive. These events often go unnoticed because they occur in unpopulated mountainous terrain during winter seasons. This was not the case in December 1964, when a major debris flow occurred in the Cave Creek drainage of the Oregon Caves National Monument. In March 1982, the National Park Service (NPS) requested a study be made to appraise the possibility of a recurrence of the 1964 debris flow in the interest of safeguarding the public and employees of the National Park Service.

From abstract: Precipitation in the Newberry caldera is nearly in balance with evaporation, evapotranspiration, and and streamflow. A small surplus of water, estimated to be in the range 2,500 to 6,500 acre-feet, is available annually for recharge to deep aquifers beneath the caldera floor.

From introduction: The purpose of this report is to describe briefly the occurrence of ground water and to present ground-water information that will help water users, public officials, and planners to determine the probability of obtaining adequate quantities of good-quality ground water in the Myrtle Creek-Glendale area.

From abstract: "A series of equations was developed to provide a better method of determining flood frequencies in the Portland-Vancouver urban area that is now available. The resulting regression equations can be used to compute peak discharge and storm runoff with a standard error of estimate of approximately thirty percent." This report contains captioned, black-and-white photographs and a colored map.

From introduction: This report outlines procedures to relate suspended-chemical concentrations (nutrients, metals, or organic constituents) associated with suspended sediments in storm-water runoff to suspended-sediment particle-size classes based on settling velocities.

From introduction: The present study is an inventory and appraisal of the water resources of the reservation, including determination of flow in major streams, yield of water to wells and springs, and quality of water. This study was conducted in cooperation with the Confederated Tribes of the Warm Springs Reservation. The cooperation and assistance of many officials of the Confederated Tribes, of the Bureau of Indian Affairs, and of the Indian Health Service helped greatly. Well-drilling and test-pumping data and other information generously furnished by Satish Puri, Tribal Engineer, were especially helpful.

From introduction: The purpose of this report is to present information that may enable water users, potential water users, and planners to estimate likelihood of obtaining ground water in adequate quantity and of suitable quality at desired locations within the study area.

Abstract: Storm runoff as related to urbanization is defined by a series of regression equations for Salem and for the Willamette Valley, Oregon. In addition to data from 17 basins monitored in the Salem area, data from 24 basins gaged in a previous study in Portland, Oregon-Vancouver, Washington were used defining the Willamette Valley equations. Basins used to define equations ranged in size from 0.2 to 26 square mi. Rainfall intensity varied from 1.8 to 2.2 in. for the 6-hour, 0.020 exceedance probability. Sensitivity analyses of equations indicate that urbanization of an undeveloped basin can increase peak discharge more than three times and almost double runoff volume. Much of Portland and Vancouver are located on porous river terraces where dry wells are used to shunt runoff. Much of east Salem is located on previously farmed land where drain tiles used to dewater soils still connect directly to streams.

From introduction: This map report is one of a series of geologic and hydrologic maps covering all or parts of States within the Basin and Range province of the western United States. The map reports contain information on subjects that characterize the geohydrology of the province, including the ground-water hydrology, ground-water quality, surface distribution of selected rock types, tectonic conditions, areal geophysics, Pleistocene lakes and marshes, and mineral and energy resources.

From introduction: This study was made in cooperation with the planning departments of Wasco and Hood River Counties, The purposes of this report are (1) to describe the occurrence, movement, availability, and quality of ground water in the basin; and (2) to assess, where possible, the extent, thickness, hydrologic boundaries, and hydraulic properties of the principal aquifers.