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At least 145 records · Page 8Linked to original sources

Geologic Map of the Piedmont Hollow Quadrangle, Oregon County, Missouri

The Piedmont Hollow 7.5-min quadrangle is located in south-central Missouri within the Salem Plateau region of the Ozark Plateaus physiographic province (Fenneman, 1938; Bretz, 1965) (fig. 1). Almost all of the land in the quadrangle north of the Eleven Point River is part of the Mark Twain National Forest. Most of the land immediately adjoining the river is part of the Eleven Point National Scenic River, also administered by the U.S. Forest Service. South of the Eleven Point River, most of the land is privately owned and used primarily for grazing cattle and horses. The quadrangle has topographic relief of about 480 feet (ft), with elevations ranging from 550 ft on the Eleven Point River at the eastern edge of the quadrangle to 1,030 ft on a hilltop about a mile to the west-northwest. The most prominent physiographic feature in the quadrangle is the valley of the Eleven Point River, which traverses the quadrangle from west to northeast.

Scientific Investigations Map↗

Water Quality Conditions in Upper Klamath and Agency Lakes, Oregon, 2006

The U.S. Geological Survey Upper Klamath Lake water quality monitoring program gathered information from multiparameter continuous water quality monitors, physical water samples, dissolved oxygen production and consumption experiments, and meteorological stations during the June-October 2006 field season. The 2006 study area included Agency Lake and all of Upper Klamath Lake. Seasonal patterns in water quality were similar to those observed in 2005, the first year of the monitoring program, and were closely related to bloom dynamics of the cyanobacterium (blue-green alga) Aphanizomenon flos-aquae (AFA) in the two lakes. High dissolved oxygen and pH conditions in both lakes before the bloom declined in July, which coincided with seasonal high temperatures and resulted in seasonal lows in dissolved oxygen and decreased pH. Dissolved oxygen and pH in Upper Klamath and Agency Lakes increased again after the bloom recovered. Seasonal low dissolved oxygen and decreased pH coincided with seasonal highs in ammonia and orthophosphate concentrations. Seasonal maximum daily average temperatures were higher and minimum dissolved oxygen concentrations were lower in 2006 than in 2005. Conditions potentially harmful to fish were influenced by seasonal patterns in bloom dynamics and bathymetry. Potentially harmful low dissolved oxygen and high un-ionized ammonia concentrations occurred mostly at the deepest sites in the Upper Klamath Lake during late July, coincident with a bloom decline. Potentially harmful pH conditions occurred mostly at sites outside the deepest parts of the lake in July and September, coincident with a heavy bloom. Instances of possible gas bubble formation, inferred from dissolved oxygen data, were estimated to occur frequently in shallow areas of Upper Klamath and Agency Lakes simultaneously with potentially harmful pH conditions. Comparison of the data from monitors in nearshore areas and monitors near the surface of the water column in the open waters of Upper Klamath Lake revealed few differences in water quality dynamics. Median daily temperatures were higher in nearshore areas, and dissolved oxygen concentrations were periodically higher as well during periods of high AFA bloom. Differences between the two areas in water quality conditions potentially harmful to fish were not statistically significant (p < 0.05). Chlorophyll a concentrations varied temporally and spatially throughout Upper Klamath Lake. Chlorophyll a concentrations indicated an algal bloom in late June and early July that was followed by an algae bloom decline in late July and early August and a subsequent recovery in mid-August. Sites in the deepest part of the lake, where some of the highest chlorophyll a concentrations were observed, were the same sites where the lowest dissolved oxygen concentrations and the highest un-ionized ammonia concentrations were recorded during the bloom decline, indicating cell senescence. Total phosphorus concentrations limited the initial algal bloom in late June and early July. The rate of net dissolved oxygen production (that is, production in excess of community respiration) and consumption (due to community respiration) in the lake water column as measured in light and dark bottles, respectively, ranged from 2.79 to -2.14 milligrams of oxygen per liter per hour. Net production rate generally correlated positively with chlorophyll a concentration, except episodically at a few sites where high chlorophyll a concentrations resulted in self-shading that inhibited photosynthesis. The depth of photic zone was inversely correlated with chlorophyll a concentration. Calculations of a 24-hour change in dissolved oxygen concentration indicated that oxygen-consuming processes predominated at the deep trench sites and oxygen-producing processes predominated at the shallow sites. In addition, calculations of the 24-hour change in dissolved oxygen indicate that oxygen-consuming processes in the water column di

Scientific Investigations Report↗

Assessing potential effects of highway runoff on receiving-water quality at selected sites in Oregon with the Stochastic Empirical Loading and Dilution Model (SELDM)

In 2012, the U.S. Geological Survey and the Oregon Department of Transportation began a cooperative study to demonstrate use of the Stochastic Empirical Loading and Dilution Model (SELDM) for runoff-quality analyses in Oregon. SELDM can be used to estimate stormflows, constituent concentrations, and loads from the area upstream of a stormflow discharge site, from the site of interest and in the receiving waters downstream of the discharge. SELDM also can be used to assess the potential effectiveness of best management practices (BMP) for mitigating potential effects of runoff in receiving waters. Nominally, SELDM is a highway-runoff model, but it is well suited for analysis of runoff from other land uses as well. This report provides case studies and examples to demonstrate stochastic-runoff modeling concepts and to demonstrate application of the model. Basin characteristics from six Oregon highway study sites were used to demonstrate various applications of the model. The highway catchment and upstream basin drainage areas of these study sites ranged from 3.85 to 11.83 acres and from 0.16 to 6.56 square miles, respectively. The upstream basins of two sites are urbanized, and the remaining four sites are less than 5 percent impervious. SELDM facilitates analysis by providing precipitation, pre-storm streamflow, and other variables by region or from hydrologically similar sites. In Oregon, there can be large variations in precipitation and streamflow among nearby sites. Therefore, spatially interpolated geographic information system data layers containing storm-event precipitation and pre-storm streamflow statistics specific to Oregon were created for the study using Kriging techniques. Concentrations and loads of cadmium, chloride, chromium, copper, iron, lead, nickel, phosphorus, and zinc were simulated at the six Oregon highway study sites by using statistics from sites in other areas of the country. Water‑quality datasets measured at hydrologically similar basins in the vicinity of the study sites in Oregon were selected and compiled to estimate stormflow-quality statistics for the upstream basins. The quality of highway runoff and some upstream stormflow constituents were simulated by using statistical moments (average, standard deviation, and skew) of the logarithms of data. Some upstream stormflow constituents were simulated by using transport curves, which are relations between stormflow and constituent concentrations. Stochastic analyses were done by using SELDM to demonstrate use of the model and to illustrate the types of information that stochastic analyses may provide: 1. An analysis was done to demonstrate use of dilution factors as an initial reconnaissance tool for comparing relative risk among sites. 2. An analysis of hardness-dependent, water-quality criteria was done to illustrate the effects of variations in hardness and flow on the application and interpretation of such criteria. This analysis shows that hardness-dependent criteria can vary by an order of magnitude among storm events because hardness is diluted by stormflows. 3. An analysis of uncertainties in input and output values was done to demonstrate that properly selected robust datasets are needed to represent conditions at a site of interest. This analysis shows that the rate of water-quality exceedances that are measured or simulated may depend on sample size and the luck of the draw. 4. An analysis was done to demonstrate that SELDM and other Monte Carlo models may generate extreme values from input statistics, which may or may not be feasible based on physicochemical or hydrological limits. 5. An analysis of BMP modeling methods was done to demonstrate use of the model for estimating treatment requirements for meeting water-quality objectives. 6. An analysis of the use of grab sampling and nonstochastic upstream modeling methods was done to evaluate the potential effects on modeling outcomes. Additional analyses using surrogate water-quality datasets for the upstream basin and highway catchment were provided for six Oregon study sites to illustrate the risk-based information that SELDM will produce. These analyses show that the potential effects of highway runoff on receiving-water quality downstream of the outfall depends on the ratio of drainage areas (dilution), the quality of the receiving water upstream of the highway, and the concentration of the criteria of the constituent of interest. These analyses also show that the probability of exceeding a water-quality criterion may depend on the input statistics used, thus careful selection of representative values is important.

Oregon↗

Evidence for distributed clockwise rotation of the crust in the northwestern United States from fault geometries and focal mechanisms

Paleomagnetic and GPS data indicate that Washington and Oregon have rotated clockwise for the past 16 Myr. Late Cenozoic and Quaternary fault geometries, seismicity lineaments, and focal mechanisms provide evidence that this rotation is accommodated by north directed thrusting and right-lateral strike-slip faulting in Washington, and SW to W directed normal faulting and right-lateral strike-slip faulting to the east. Several curvilinear NW to NNW trending high-angle strike-slip faults and seismicity lineaments in Washington and NW Oregon define a geologic pole (117.7°W, 47.9°N) of rotation relative to North America. Many faults and focal mechanisms throughout northwestern U.S. and southwestern British Columbia have orientations consistent with this geologic pole as do GPS surface velocities corrected for elastic Cascadia subduction zone coupling. Large Quaternary normal faults radial to the geologic pole, which appear to accommodate crustal rotation via crustal extension, are widespread and can be found along the Lewis and Clark zone in Montana, within the Centennial fault system north of the Snake River Plain in Idaho and Montana, to the west of the Wasatch Front in Utah, and within the northern Basin and Range in Oregon and Nevada. Distributed strike-slip faults are most prominent in western Washington and Oregon and may serve to transfer slip between faults throughout the northwestern U.S.

British Columbia, Oregon, Washington↗

Geologic map and database of the Roseburg 30' x 60' quadrangle, Douglas and Coos Counties, Oregon

The Roseburg 30' x 60' Quadrangle covers the southeastern margin of the Oregon Coast Range and its tectonic boundary with Mesozoic terranes of the Klamath Mountains (see figures 1 and 2 in pamphlet, also shown on map sheet). The geologic framework of the Roseburg area was established by the pioneering work of Diller (1898), Wells and Peck, (1961) and Ewart Baldwin (1974) and his students (see figure 3 in pamphlet, also shown on map sheet). Baldwin and his students focussed on the history of the Eocene Tyee basin, where the sediments lap across the tectonic boundary with the Mesozoic terranes and record the accretion of the Coast Range basement to the continent. Others have examined the sedimentary fill of the Tyee basin in detail, recognizing the deep marine turbidite facies of the Tyee Formation (Snavely and others, 1964) and proposing several models for the Eocene evolution of the forearc basin (Heller and Ryberg, 1983; Chan and Dott, 1983; Heller and Dickinson, 1985; Molenaar, 1985; see Ryu and others, 1992 for a comprehensive summary). Along the eastern margin of the quadrangle, both the Tyee basin and the Klamath terranes are overlain by Eocene volcanic rocks of the Western Cascade arc (Walker and MacLeod, 1991). The thick Eocene sedimentary sequence of the Tyee basin has significant oil and gas potential (Armentrout and Suek, 1985; Gautier and others, 1993; Ryu and others, 1996). Although 13 deep test wells have been drilled in the Roseburg quadrangle (see figure 2 and table 1 in pamphlet, also shown on map sheet), exploration to date has been hampered by an incomplete understanding of the basin�s tectonic setting and evolution. In response, the Oregon Department of Geology and Mineral Industries (DOGAMI) initiated a five year assessment of the oil and gas potential of the Tyee basin. This map is a product of a cooperative effort by the U. S. Geological Survey, Oregon State University, and DOGAMI to systematically map the sedimentary facies and structure of the Tyee basin. New geologic mapping of twenty-eight 7.5' quadrangles is summarized on the map (see figure 3, also shown on map sheet), and the digital database contains geologic information suitable for both 1:100K and 1:24K scale analysis. DOGAMI has published a compilation and synthesis of previous mapping (Niem and Niem, 1990), a basin-wide sequence stratigraphic model and correlations (Ryu and others, 1992), and a report on the oil and gas potential (Ryu and others, 1996). Readers interested in the oil and gas potential of the Roseburg quadrangle should use the map in combination with Ryu and others (1996) to address specific stratigraphic units and structural plays. Stratigraphic terminology for the Tyee basin adopts the type sections, formation names, and framework of Ryu and others (1992, 1996), which were developed concurrently with the mapping and are recognized throughout the basin. For detailed discussion of nomenclature, type sections, lithology, thickness and distribution, age, contact relationships, and depositional environment of stratigraphic units, the reader is referred to Ryu and others (1992). In this report we focus on the spatial, temporal, and structural relationships between units revealed by geologic mapping. Map unit ages (see figure 4 in pamphlet, also shown on map sheeet) are adjusted slightly from Ryu and others (1992, 1996) to fit new coccolith age determinations (D. Bukry, cited in pamphlet), paleomagnetic polarity data (Simpson, 1977 and new data cited in pamphlet), and the time scale of Berggren and others (1995).

Oregon↗

Geothermal implications of a refined composition-age geologic map for the volcanic terrains of southeast Oregon, northeast California, and southwest Idaho, USA

Sufficient temperatures to generate steam likely exist under most of the dominantly volcanic terrains of southeast Oregon, northeast California, and southeast Idaho, USA, but finding sufficient permeability to allow efficient advective heat exchange is an outstanding challenge. A new thematic interpretation of existing state-level geologic maps provides an updated and refined distribution of the composition and age of geologic units for the purposes of assessing the implications for measurement and development of geothermal resources. This interpretation has been developed to better understand geothermal and hydrologic resources of the region. Comparison of the new geologic categories with available hydrologic data shows that younger volcanogenic terrains tend to have higher primary permeability than older terrains. Decrease in primary permeability with age is attributable to weathering and hydrothermal alteration of volcanogenic deposits to pore-filling clays and deposition of secondary deposits (e.g., zeolites). Spring density as a function of geology and precipitation can be used to infer groundwater flow path length within the upper aquifers. Beneath the upper aquifers, we postulate that, due to accelerated hydrothermal alteration at temperatures ~>30 °C, primary permeability at depths of geothermal interest will be limited, and that secondary permeability is a more viable target for hydrothermal fluid withdrawal. Because open fractures resulting from tensile stresses will affect all geologic layers, regions with a significant amount of groundwater flow through shallow, structurally controlled secondary permeability may overlay zones of deep secondary permeability. Regardless of whether the shallow permeability is connected with the deep permeability, shallow groundwater flow can mask the presence of deep hydrothermal flow, resulting in blind geothermal systems. Ideally, hydraulic connectivity between shallow and deep secondary permeability is limited, so that shallow groundwater does not cool potential geothermal reservoirs.

Conference Paper↗

Dissolved-oxygen and algal conditions in selected locations of the Willamette River basin, Oregon

During July and August 1978, the U.S. Geological Survey, in cooperation with the Oregon Department of Enviromental Quality, made three intensive river-quality dissolved-oxygen studies in the upper Willamette River basin. Two studies were made on the upper Willamette River and one was made on the Santiam River, a Willamette River tributary. Nitrification, occurring in both the upper Willamette and South Santiam Rivers, accounted for about 62% and 92% of the DO sag in the rivers, respectively. Rates of nitrification were found to be dependent on ammonia concentrations in the rivers. Periphyton and phytoplankton algal samples were collected on the main stem Willamette River and selected tributaries during August 1978. Diatoms were the dominant group in both the periphyton and phytoplankton samples. The most common diatom genera were Melosira, Stephanodiscus, Cymbella, Achnanthes, and Nitzschia. Comparisons with historical data indicate no significant difference from previous years in the total abundance or diversity of the algae. (USGS)

Open-File Report↗

Occurrence and distribution of pesticides in surface waters of the Hood River basin, Oregon, 1999-2009

The U.S. Geological Survey analyzed pesticide and trace-element concentration data from the Hood River basin collected by the Oregon Department of Environmental Quality (ODEQ) from 1999 through 2009 to determine the distribution and concentrations of pesticides in the basin's surface waters. Instream concentrations were compared to (1) national and State water-quality standards established to protect aquatic organisms and (2) concentrations that cause sublethal or lethal effects in order to assess their potential to adversely affect the health of salmonids and their prey organisms. Three salmonid species native to the basin are listed as "threatened" under the U.S. Endangered Species Act: bull trout, steelhead, and Chinook salmon. A subset of 16 sites was sampled every year by the ODEQ for pesticides, with sample collection targeted to months of peak pesticide use in orchards (March-June and September). Ten pesticides and four pesticide degradation products were analyzed from 1999 through 2008; 100 were analyzed in 2009. Nineteen pesticides were detected: 11 insecticides, 6 herbicides, and 2 fungicides. Two of four insecticide degradation products were detected. All five detected organophosphate insecticides and the one detected organochlorine insecticide were present at concentrations exceeding water-quality standards, sublethal effects thresholds, or acute toxicity values in one or more samples. The frequency of organophosphate detection in the basin decreased during the period of record; however, changes in sampling schedule and laboratory reporting limits hindered clear analysis of detection frequency trends. Detected herbicide and fungicide concentrations were less than water-quality standards, sublethal effects thresholds, or acute toxicity values. Simazine, the most frequently detected pesticide, was the only herbicide detected at concentrations within an order of magnitude (factor of 10) of concentrations that impact salmonid olfaction. Some detected pesticides are of concern, not for their toxicity alone, but for their ability to potentiate the harmful impacts of other pesticides, particularly organophosphates, on salmonids or their prey. Many samples contained mixtures of pesticides, but the effects to salmonids of relevant mixtures at environmentally realistic concentrations for the basin are unknown. Trace-element concentration data, although limited, indicate that eight trace elements are also of concern for their potential to harm salmonid health. The dataset is limited with regard to the spatial and seasonal distribution of pesticides and trace elements in all salmonid-bearing streams, the presence of particle-bound pesticides, and the presence of several unmonitored pesticides known to be used in the basin.

Oregon↗

Geologic map of the Dog River and northern part of the Badger Lake 7.5′ quadrangles, Hood River County, Oregon

The Dog River and northern part of the Badger Lake 7.5' quadrangles encompasses an area of ~201 km2 (77.6 mi2) of the High Cascades of north-central Oregon, lying across the eastern slopes of Mount Hood volcano (Figure 1-1; Plate 1; referred to herein as Dog River–Badger Lake area). Mount Hood, known as Wy’east to Native Americans, is Oregon’s tallest peak (3,427 m [11,241 ft]). The volcano has erupted episodically for the past 500,000 years, experiencing two major eruptive periods during the last 1,500 years (Scott and others, 1997a; Scott and others, 2003; Scott and Gardner, 2017). Cascade Range volcanism and structural development in the area dates back longer, with eruptive activity dating from latest Miocene to recent time; part of that volcano-tectonic record is detailed by new high-resolution geologic mapping presented here. The geology of the Dog River–Badger Lake area was mapped by the Oregon Department of Geology and Mineral Industries (DOGAMI) between 2017 and 2020, in collaboration with geoscientists from the U. S. Geological Survey Cascade Volcano Observatory (USGS CVO) and Hamilton College, New York. The primary objective of this investigation is to provide an updated and spatially accurate geologic framework for the Dog River–Badger Lake area as part of a multi-year study of the geology of the larger Middle Columbia Basin (Figure 1-1, Figure 1-2). Additional key objectives of this project are to: 1) determine the geologic history of volcanic rocks in this part of the northern Oregon Cascade Range, including lava flows and volcaniclastic deposits erupted from Middle Pleistocene to Holocene Mount Hood volcano; 2) provide significant new details about the structure and fault history along the northern segment of the High Cascades intra-arc graben (Hood River graben); and 3) better understand geologic hazards in the region, related to earthquakes, volcanoes, and landslides. New detailed geologic data presented here also provides a basis for future geologic, geohydrologic, and geohazard studies in the greater Middle Columbia Basin. Detailed geologic mapping in this part of the Middle Columbia Basin is a high priority of the Oregon Geologic Map Advisory Committee (OGMAC), supported in part by grants from the STATEMAP component of the USGS National Cooperative Geologic Mapping Program (G17AC00210, G19AC00160). Additional funds were provided by the State of Oregon. The core products of this study are this report, an accompanying geologic map and cross sections (Plate 1), an Esri ArcGIS™ geodatabase, and Microsoft Excel® spreadsheets tabulating point data for geochemistry, geochronology, magnetic polarity, orientation points, and well data. The geodatabase presents the new geologic mapping in a digital format consistent with the USGS National Cooperative Geologic Mapping Program Geologic Map Schema (GeMS) (U.S. Geological Survey National Cooperative Geologic Mapping Program, 2020). This geodatabase contains spatial information, including geologic polygons, contacts, structures, geochemistry, geochronology, magnetic observation, orientation points, and well data, as well as data about each geologic unit such as age, lithology, mineralogy, and structure. Digitization at scales of 1:8,000 or better was accomplished using a combination of high-resolution lidar topography and imagery. Surficial and bedrock geologic units contained in the geodatabase are depicted on the Plate 1 at a scale of 1:24,000. Both the geodatabase and geologic map are supported by this report describing the geology in detail.

Oregon↗

Geologic Map of the Wilderness and Handy Quadrangles, Oregon, Carter, and Ripley Counties, Missouri

The bedrock exposed in the Wilderness and Handy Quadrangles, Missouri, comprises Early Ordovician aged dolomite, sandstone, and chert. The sedimentary rocks are nearly flat-lying except where they are adjacent to faults. The carbonate rocks are karstified and the area contains numerous sinkholes, springs, caves, and losing-streams. This map is one of several being produced under the U.S. Geological Survey National Cooperative Geologic Mapping Program to provide geologic data applicable to land-use problems in the Ozarks of south-central Missouri. Ongoing and potential industrial and agricultural development in the Ozarks region has presented issues of ground-water quality in karst areas. These quadrangles contain significant areas of the Mark Twain National Forest, including part of the Eleven Point National Scenic Riverway and the Irish Wilderness Roadless Area. A National Park in this region (Ozark National Scenic Riverways, Missouri ) is concerned about the effects of activities in areas outside of their stewardship on the water resources that define the heart of this Park. This task applies geologic mapping and karst investigations to address issues surrounding competing land use in south-central Missouri. For more information see: http://geology.er.usgs.gov/eespteam/Karst/index.html

IMAP↗

Guides to some volcanic terranes in Washington, Idaho, Oregon, and Northern California

This guidebook arose out of a series of field trips held in conjunction with the Pacific Northwest American Geophysical Union meeting held in Bend, Oregon, September 1979. The PNAGU meeting included special volcanology sessions planned by William I. Rose, Jr., Bruce A. Nolf, amd David A. Johnston. Publication of the guidebook volume was originally planned for early 1980 by the Oregon Department of Geology and Mineral Industries (DOGAMI). Inevitable delays, subsequent scheduling problems, and the death of Dave Johnston in the May 18 eruption of Mount St. Helens led to this publication as a USGS Circular. This circular differs from typical U.S. Geological Survey compilations in that not all these papers have been examined by the Geologic Names Committee of the Survey. This Committee is charged with ensuring consistent usage of formational and other stratigraphic names in U.S. Geological Survey publications. Because many of the contributions are from workers outside the Survey, review by the Geologic Names Committee would have been inappropriate. Each author provided camera-ready pages, and the articles have not been edited for uniformity of style or usage. The contributions are generally ordered so as to describe the areas from north to south. Typically, the roadlog comes after the descriptive article except in the case of the Medicine Lake Highland articles, for which the road log is first and several topical contributions follow.

California, Idaho, Oregon, Washington↗

The 3D Elevation Program: summary for Oregon

Elevation data are essential to a broad range of business uses, including forest resources management, wildlife and habitat management, national security, recreation, and many others. In the State of Oregon, elevation data are critical for river and stream resource management; forest resources management; water supply and quality; infrastructure and construction management; wildfire management, planning and response; natural resources conservation; and other business uses. Today, high-density light detection and ranging (lidar) data are the primary source for deriving elevation models and other datasets. The Oregon Lidar Consortium (OLC), led by the Oregon Department of Geology and Mineral Industries (DOGAMI), has developed partnerships with Federal, State, Tribal, and local agencies to acquire quality level 1 data in areas of shared interest. The goal of OLC partners is to acquire consistent, high-resolution and high-quality statewide coverage to support existing and emerging applications enabled by lidar data. The National Enhanced Elevation Assessment evaluated multiple elevation data acquisition options to determine the optimal data quality and data replacement cycle relative to cost to meet the identified requirements of the user community. The evaluation demonstrated that lidar acquisition at quality level 2 for the conterminous United States and quality level 5 ifsar data for Alaska with a 6- to 10-year acquisition cycle provided the highest benefit/cost ratios. The 3D Elevation Program (3DEP) initiative selected an 8-year acquisition cycle for the respective quality levels. 3DEP, managed by the U.S. Geological Survey (USGS), the Office of Management and Budget Circular A&ndash;16 lead agency for terrestrial elevation data, responds to the growing need for high-quality topographic data and a wide range of other 3D representations of the Nation&rsquo;s natural and constructed features.

Oregon↗

Beaver dams and their effects on urban streams in the Tualatin River Basin, northwestern Oregon

Introduction In response to growing interest in beaver-assisted restoration in the Tualatin River Basin of northwestern Oregon, the U.S. Geological Survey (USGS), in partnership with Clean Water Services, collected data from 2016–17 and completed a series of studies to: (1) inventory known locations of beaver dams and activity in the Tualatin River Basin, (2) estimate the number of beaver dams in the Tualatin River Basin as of 2017 and the potential number of beaver dams that could be supported with riparian vegetation improvements, and (3) assess the effects of beaver dams and ponds on storm hydrology, hydraulics, and floodplain inundation, suspended-sediment transport and deposition, and water quality along two urban stream reaches (Fanno Creek at Greenway Park and Bronson Creek between Kaiser and Saltzman Roads). This fact sheet summarizes the results of these studies and implications for beaver-assisted restoration in the Tualatin River Basin.

Oregon↗

GIS database and discussion for the distribution, composition, and age of Cenozoic volcanic rocks of the Pacific Northwest Volcanic Aquifer System study area

A substantial part of the U.S. Pacific Northwest is underlain by Cenozoic volcanic and continental sedimentary rocks and, where widespread, these strata form important aquifers. The legacy geologic mapping presented with this report contains new thematic categorization added to state digital compilations published by the U.S. Geological Survey for Oregon, California, Idaho, Nevada, Utah, and Washington (Ludington and others, 2005). Our additional coding is designed to allow rapid characterization, mainly for hydrogeologic purposes, of similar rocks and deposits within a boundary expanded slightly beyond that of the Pacific Northwest Volcanic Aquifer System study area. To be useful for hydrogeologic analysis and to be more statistically manageable, statewide compilations from Ludington and others (2005) were mosaicked into a regional map and then reinterpreted into four main categories on the basis of (1) age, (2) composition, (3) hydrogeologic grouping, and (4) lithologic pattern. The coding scheme emphasizes Cenozoic volcanic or volcanic-related rocks and deposits, and of primary interest are the codings for composition and age.

Pacific Northwest Volcanic Aquifer System↗

Lithologic log of drill cuttings for DOGAMI heat flow hole CR-SB, Mount Hood, Oregon

CR-SB is one of three shallow (-82.0 m) heat flow holes drilled in 1976 at Mount Hood, Oregon by the Oregon Department of Geology and Mineral Industries (DOGAMI). Drill hole CR-SB was located on the southern flank of the mountain near the Snow Bunny ski lodge at an elevation of 1167.7 m (T 3 S, R 8.5 E, Sec. 25 AA) (Fig. 1). Temperatures, measured at 5.0 m intervals, and geothermal gradient data for the drill hole are given in Hull, Blackwell, and Black (1978) and are reproduced in Table 1 and Figures 2 and 3 in this report. Blackwell and Steele (1979) give an average thermal conductivity, based upon 6 samples of drill cuttings, of 4.53 (standard error =0.26) but indicated that the data obtained from the drill hole are unsuitable for heat flow calculations. Splits of the drill cuttings were obtained courtesy of J. F. Riccio (DOGAMI). The drill cuttings were wet sieved through a 200 mesh (0.074 mm) screen and both fractions were air dried and saved. Representative rock types and alteration material were hand-picked from the coarse fraction using a binocular microscope. Slurry slides of finely-ground cuttings were routinely run at 1/2°/min. from 3° to 37° 20 using unfiltered CuK radiation on a Norelco 1/ X-ray diffractometer equipped with a focusing monochrometer.

Oregon↗

Ground water in Myrtle Creek - Glendale area, Douglas County, Oregon

The Myrtle Creek-Glendale area covers about 400 mi 2 (1,000 km 2 in Douglas County in southwestern Oregon. Although the geologic formations of the area have low permeabilities and generally yield small amounts of water to wells, ground water is the chief source of water for domestic usse in rural parts of the area not served by public supplies. A well capable of yielding 5 to 10 gal/min (0.3 to 0.6 L/s) can supply household needs. In most places in the area, the quantities of water obtainable from wells are inadequate or would be only marginally adequate for irrigation, municipal, of large industrial use. 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 quanitities of good-quality ground water in the Myrtle Creek-Glendale area.

Oregon↗

Water quality of the lower Columbia River Basin: Analysis of current and historical water-quality data through 1994

The lower Columbia River Basin includes the river basins draining into the Columbia River below Bonneville Dam&mdash;the largest of which is the Willamette River. This report presents the results of a study by the U.S. Geological Survey, done in cooperation with the Lower Columbia River Bi-State Water- Quality Program, to describe the water-quality conditions in the lower Columbia River Basin by interpreting historical data collected and data collected in 1994. Historical water-quality data spanning more than 50 years and comprising more than 200 parameters were collated for interpretation in this report. The U.S. Geological Survey, the Oregon Department of Environmental Quality, and the Washington Department of Ecology collected water-quality data at 10 sites in the lower Columbia River Basin from January to December of 1994. Water-quality constituents measured in 1994 were screened against U.S. Environmental Protection Agency (EPA) and State guidelines. Arsenic, a human carcinogen, was detected in 15 of 16 samples in the lower Columbia River, but was not detected in any of the sampled tributaries. All 15 arsenic detections had concentrations that exceeded both the EPA ambient water-quality criteria for the protection of human health and the EPA human-health advisories for drinking water. Chromium was detected at all four Columbia River sites&mdash;most frequently in the Columbia River at Hayden Island. None of the chromium concentrations detected, however, exceeded water-quality criteria or guidelines. Measurements of suspended trace-element concentrations (trace-element concentrations associated with the suspended-sediment fraction) showed that the suspended form is the dominant transport phase for aluminum, iron, and manganese, whereas the dissolved form is the dominant transport phase for arsenic, barium, chromium, and copper. On the basis of tributary loads during summer low-flow months, sources of suspended silver, nickel, aluminum, and antimony exist in the lower Columbia River Basin, whereas the sources of suspended zinc and arsenic exist outside of the lower basin. Twenty organic compounds were detected of the 47 compounds analyzed for this study. None of the organic compounds measured exceeded EPA&rsquo;s ambient water-quality criteria or drinking-water guidelines. The Willamette River at Portland had the largest number of detections, and all 20 compounds were detected at one time or another at that site. The largest concentrations of the agricultural pesticides, atrazine, metolachlor, and simazine were detected in the Willamette River, where they were detected in 93, 86, 93 percent, respectively, of the samples collected. The highest concentrations of atrazine in the Willamette River were associated with the spring application and fall runoff periods. Both historical and current data showed that the highest water temperatures in the lower Columbia River Basin are present during August. For water years 1977&ndash;81 in the Columbia River at Bradwood (river mile 38.9), 75 percent of the daily mean water temperatures during August exceeded 20 degrees Celsius, a &ldquo;special condition&rdquo; criterion for the State of Washington. The special condition criterion was exceeded at four sites on the lower Columbia River during July and August, 1994&mdash;a period coinciding with season-high air temperatures and low streamflow. Trend tests using data from 1974 to 1994 showed significant (r < 0.05) upward trends for water temperature at the Columbia River at Warrendale and the Willamette River at Portland. Concentrations of dissolved oxygen and total dissolved gas were above saturation levels during high stormflows in the lower Columbia River and the Willamette River during 1994. The high concentrations of total dissolved gas in the Columbia River exceeded Oregon and Washington State standards of 110 percent of saturation and were caused by spilling water at the Columbia River dams. Aquatic life in the lower Columbia River Basin was not subjected to low dissolved-oxygen concentrations. Comparison of dissolved-oxygen concentrations in the Willamette River from 1949&ndash;58 to 1972&ndash;94 showed a significant increase in dissolved-oxygen concentrations during the low-streamflow months of summer. Trend tests showed significant (r < 0.05) downward trends from 1973 to 1994 for three constituents at the Columbia River at Warrendale: phosphorus in unfiltered water, total dissolved solids, and specific conductance. These trends may be a consequence of more conservative agricultural practices in the area upstream from Warrendale.

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Geothermal potential of the Umatilla Indian Reservation, Oregon: Evidence from detailed geophysical investigations

Recent geologic and geophysical investigations were undertaken in northeastern Oregon to better assess earthquake hazards in the region and determine relative favorability for geothermal energy development on lands of the Confederated Tribes of the Umatilla Indian Reservation (CTUIR). This work was funded in part by a Bureau of Indian Affairs grant awarded to the CTUIR to identify areas most suitable for further exploration of geothermal resources. Results from this work were utilized as inputs to a geothermal favorability modeling process that led to the identification of target sites for further geothermal investigation. Beyond the geothermal aspect of this project, the region is of great tectonic significance as it marks the intersection of two major physiographic and geophysical features, the Klamath-Blue Mountain lineament (KBL) and Olympic-Wallowa lineament (OWL), inferred to represent major basement boundaries. The Thorn Hollow and Hite faults, which appear to be major linkages between the KBL and OWL, run through the study area. New aeromagnetic, gravity and magnetotelluric (MT) surveying, along with fault analyses, were conducted as part of this effort. Detailed geophysical exploration resulted in the collection of 1,380 new gravity stations, 34,524-line kilometers of aeromagnetic data (covering 12,524 km2) and measurements from 36 MT stations. Two-dimensional (2D) forward-modeling was executed along several profiles using gravity and aeromagnetic data, combined with existing geologic mapping and rock property constraints measured from hand samples and outcrops. These models are used to define lithologic contacts in the subsurface in the absence of well logs or borehole data to determine possible geothermal fluid reservoirs, as well as identify major structures that may act as conduits for the upward migration of geothermal fluids.

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