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USGS1997

Evaluation of geophysical logs, Phase I, at Willow Grove Naval Air Station, Montgomery County, Pennsylvania

Between April and June 1997, the U.S. Navy contracted Brown and Root Environmental, Inc., to drill 20 monitor wells at the Willow Grove Naval Air Station in Horsham Township, Montgomery County, Pa. The wells were installed to monitor water levels and allow collection of water samples from shallow, intermediate, and deep water-bearing zones. Analysis of the samples will determine the horizontal and vertical distribution of any contaminated ground water migrating from known contaminant sources. Eight wells were drilled near the Fire Training Area (Site 5), five wells near the 9th Street Landfill (Site 3), four wells at the Antenna Field Landfill (Site 2), and three wells near Privet Road Compound (Site 1). Depths range from 73 to 167 feet below land surface. The U.S. Geological Survey conducted borehole-geophysical and borehole-video logging to identify water-bearing zones so that appropriate intervals could be screened in each monitor well. Geophysical logs were run on the 20 monitor wells and 1 existing well. Video logs were run on 16 wells. Caliper and video logs were used to locate fractures, inflections on fluid-temperature and fluid-resistivity logs were used to locate possible water-bearing fractures, and flowmeter measurements verified these locations. Single-point-resistance and natural-gamma logs provided information on stratigraphy. After interpretation of geophysical logs, video logs, and driller's notes, all wells were screened such that water-level fluctuations could be monitored and discrete water samples collected from one or more shallow and intermediate water-bearing zones in each borehole.

Open-File Report↗

USGS2002

Water quality and aquatic communities of upland wetlands, Cumberland Island National Seashore, Georgia, April 1999 to July 2000

Cumberland Island is the southernmost and largest barrier island along the coast of Georgia. The island contains about 2,500 acres of freshwater wetlands that are located in a variety of physical settings, have a wide range of hydroperiods, and are influenced to varying degrees by surface and ground water, rainwater, and seawater. In 1999-2000, the U.S. Geological Survey, in cooperation with the National Park Service, conducted a water-quality study of Cumberland Island National Seashore to document and interpret the quality of a representative subset of surface- and ground-water resources for management of the seashore's natural resources. As part of this study, historical ground-water, surface-water, and ecological studies conducted on Cumberland Island also were summarized. Surface-water samples from six wetland areas located in the upland area of Cumberland Island were collected quarterly from April 1999 to March 2000 and analyzed for major ions, nutrients, trace elements, and field water-quality constituents including specific conductance, pH, temperature, dissolved oxygen, alkalinity, tannin and lignin, and turbidity. In addition, water temperature and specific conductance were recorded continuously from two wetland areas located near the mean high-tide mark on the Atlantic Ocean beaches from April 1999 to July 2000. Fish and invertebrate communities from six wetlands were sampled during April and December 1999. The microbial quality of the near-shore Atlantic Ocean was assessed in seawater samples collected for 5 consecutive days in April 1999 at five beaches near campgrounds where most recreational water contact occurs. Ground-water samples were collected from the Upper Floridan aquifer in April 1999 and from the surficial aquifer in April 2000 at 11 permanent wells and 4 temporary wells (drive points), and were analyzed for major ions, nutrients, trace elements, and field water-quality constituents (conductivity, pH, temperature, dissolved oxygen, and alkalinity). Fecal-coliform bacteria concentrations were measured, but not detected, in samples collected from two domestic water-supply wells. During the 12-month period from April 1999 to March 2000 when water-quality and aquatic-community samples were collected, rainfall was 12.93 inches below the 30-year average rainfall. Constituent concentrations were highly variable among the different wetlands during the study period. Rainfall and tidal surges associated with tropical storms and hurricanes substantially influenced water quantity and quality, particularly in wetland areas directly influenced by tidal surges. Although surface waters on Cumberland Island are not used as sources of drinking water, exceedances of U.S. Environmental Protection Agency primary and secondary standards for drinking water were noted for comparative purposes. A nitrate concentration of 12 milligrams per liter in one sample from Whitney outflow was the only exceedance of a maximum contaminant level. Secondary standards were exceeded in 26 surface-water samples for the following constituents: pH (10 exceedances), chloride (8), sulfate (5), total dissolved solids (4), iron (2), fluoride (1), and manganese (1). The total-dissolved-solids concentrations and the relative abundance of major ions in surface-water samples collected from wetlands on Cumberland Island provide some insight into potential sources of water and influences on water quality. Major-ion chemistries of water samples from Whitney Lake, Willow Pond, and South End Pond 3 were sodium-chloride dominated, indicating direct influence from rainwater, salt aerosol, or inundation of marine waters. The remaining wetlands sampled had low total-dissolved-solids concentrations and mixed major-ion chemistries--North Cut Pond 2A was magnesium-sodium-chloride-sulfate dominated and Lake Retta and the two beach outflows were sodium-calcium-bicarbonate-chloride dominated. The higher percent calcium and bicarbonate in some wetlands sugg

Georgia↗

USGS1983

Geologic and geophysical investigations of Climax Stock intrusive, Nevada

The Climax stock is a composite granitic intrusive of Cretaceous age, composed of quartz monzonite and granodiorite, which intrudes rocks of Paleozoic and Precambrian age. Tertiary volcanic rocks, consisting of ashflow and ash-fall tuffs, and tuffaceous sedimentary rocks overlie the sedimentary rocks and the stock. Erosion has removed much of the Tertiary volcanic rocks. Hydrothermal alteration of quartz monzonite and granodiorite is found mainly along joints and faults and varies from location to location. The Paleozoic carbonate rocks have been thermally and metasomatically altered to marble and tactite as much as 457 m (1,500 ft) from the contact with the stock, although minor discontinuous metasomatic effects are noted in all rocks out to 914 m (3,000 ft). Three major faults which define the Climax area structurally are the Tippinip, Boundary and Yucca faults. North of the junction of the Boundary and Yucca faults, the faults are collectively referred to as the Butte fault. The dominant joint sets and their average attitudes are N. 32? W., 22? NE; N. 60? W., vertical and N. 35? E., vertical. Joints in outcrop are weathered and generally open, but in subsurface, the joints are commonly filled and healed with secondary mineral s. The location of the water table and the degree of saturation of the granitic rocks are presently unknown. Measurement from drill holes indicated that depth to perched water levels ranges from 30 to 244 m (100-800 ft). Recent field investigations have shown the contact between the Pogonip marble and the granodiorite is a contact rather than a fault as previously mapped. The thickness of the weathered granodiorite is estimated to be 8 to 46 m (25 to 150 ft).

Open-File Report↗

USGS1999

Simulation of the effects of nearby quarrying operations on ground-water flow at the South Well Field, Franklin County, Ohio

The City of Columbus, Ohio, operates a municipal well field in southern Franklin County that is adjacent to a sand and gravel mining operation. Mining operations have the potential to alter ground-water flowpaths and change the sources of water to pumped wells. Previous ground-water-flow modeling of the area has shown that water pumped from the supply wells is derived from infiltration from nearby rivers and surrounding bedrock. Some of that water flows through existing quarries. Because water quality differs among these sources and is affected by the path along which water flows to the wells, five flow conditions were simulated to evaluate the influence of different mining scenarios on sources of water as related to the size and shape of contributing recharge areas (CRAs) to wells. The first simulation was based on a revision of an existing model by Schalk (1996). The second and third simulations included one in which a 20-foot layer of undisturbed aquifer material within the quarry above the bedrock is left intact, and another in which the 20-foot layer is removed. The fourth and fifth simulations included one in which the 20-foot layer of undisturbed aquifer material is left above the bedrock and the quarry is backfilled with fine- grained sand and silt (a byproduct of the mining operations), and another in which the 20-foot layer is removed before the quarry is backfilled with the fine-grained sand and silt. The results of the five model simulations indicate that the overall volumetric budgets among models change only slightly in response to changing conditions at the quarry. The most significant change is noted in the amount of water that the aquifers gained from constant head and river leakage. This change is due to the way the quarries were simulated and lower heads in the aquifers compared to those in simulations made with earlier models. Previously published model simulations showed that the 5-year CRAs did not extend into the area of the newest sand and gravel quarry. In this study, however, the size and shape of the CRAs differ in response to the addition of two supply wells, and the 5-year CRA for one of these wells intersects the sand and gravel quarry. Particle-tracking analysis indicates that the proportions of water from the principal water sources -- rivers, other quarries (excluding the quarry of interest), and bedrock -- stayed relatively constant among the model simulations. The number of particles that originate in the quarry of interest increased from about 1 percent of the total particles withdrawn through all wells when the 20-foot layer of undisturbed aquifer material was left intact, to 2 percent when the 20-foot layer was removed. In simulations in which the quarry of interest was filled with fine-grained sand and silt, the percentage of particles that travel through or originate in that quarry decreased to less than 1 percent of the total number of particles. Thus, the mining activities at the quarry of interest, combined with increased pumping at the two supply wells have only a small potential to change the overall water quality of water withdrawn from supply wells at the South Well Field.

Water-Resources Investigations Report↗

USGS2023

Comparing NISAR (using Sentinel-1), USDA/NASS CDL, and ground truth crop/non-crop areas in an urban agricultural region

A general limitation in assessing the accuracy of land cover mapping is the availability of ground truth data. At sites where ground truth is not available, potentially inaccurate proxy datasets are used for sub-field-scale resolution investigations at large spatial scales, i.e., in the Contiguous United States. The USDA/NASS Cropland Data Layer (CDL) is a popular agricultural land cover dataset due to its high accuracy (>80%), resolution (30 m), and inclusions of many land cover and crop types. However, because the CDL is derived from satellite imagery and has resulting uncertainties, comparisons to available in situ data are necessary for verifying classification performance. This study compares the cropland mapping accuracies (crop/non-crop) of an optical approach (CDL) and the radar-based crop area (CA) approach used for the upcoming NASA-ISRO Synthetic Aperture Radar (NISAR) L- and S-band mission but using Sentinel-1 C-band data. CDL and CA performance are compared to ground truth data that includes 54 agricultural production and research fields located at USDA’s Beltsville Agricultural Research Center (BARC) in Maryland, USA. We also evaluate non-crop mapping accuracy using twenty-six built-up and thirteen forest sites at BARC. The results show that the CDL and CA have a good pixel-wise agreement with one another (87%). However, the CA is notably more accurate compared to ground truth data than the CDL. The 2017–2021 mean accuracies for the CDL and CA, respectively, are 77% and 96% for crop, 100% and 94% for built-up, and 100% and 100% for forest, yielding an overall accuracy of 86% for the CDL and 96% for CA. This difference mainly stems from the CDL under-detecting crop cover at BARC, especially in 2017 and 2018. We also note that annual accuracy levels varied less for the CA (91–98%) than for the CDL (79–93%). This study demonstrates that a computationally inexpensive radar-based cropland mapping approach can also give accurate results over complex landscapes with accuracies similar to or better than optical approaches.

Maryland↗

USGS2002

Generalized surficial geologic map of the Pueblo 1° x 2° quadrangle, Colorado

Fifty-three types of surficial geologic deposits and residual materials of Quaternary age are described in a pamphlet and located on a map of the greater Pueblo area, in part of the Front Range, in the Wet and Sangre de Cristo Mountains, and on the plains east of Colorado Springs and Pueblo. Deposits formed by landslides, wind, and glaciers, as well as colluvium, residuum, alluvium, and others are described in terms of predominant grain size, mineral or rock composition (e.g., gypsiferous, calcareous, granitic, andesitic), thickness, and other physical characteristics. Origins and ages of the deposits and geologic hazards related to them are noted. Many lines drawn between units on our map were placed by generalizing contacts on published maps. However, in 1997-1999 we mapped new boundaries as well. The map was projected to the UTM projection. This large map area extends from near Salida (on the west edge), eastward about 107 mi (172 km), and from Antero Reservoir and Woodland Park on the north edge to near Colorado City at the south edge (68 mi; 109 km).

Colorado↗

USGS2005

Environmental contaminants and biomarker responses in fish from the Rio Grande and its U.S. tributaries: Spatial and temporal trends

We collected, examined, and analyzed 368 fish of seven species from 10 sites on rivers of the Rio Grande Basin (RGB) during late 1997 and early 1998 to document temporal and geographic trends in the concentrations of accumulative contaminants and to assess contaminant effects on the fish. Sites were located on the mainstem of the Rio Grande and on the Arroyo Colorado and Pecos River in Texas (TX), New Mexico (NM), and Colorado. Common carp (Cyprinus carpio) and largemouth bass (Micropterus salmoides) were the targeted species. Fish were examined in the field for internal and external visible gross lesions, selected organs were weighed to compute ponderal and organosomatic indices, and samples of tissues and fluids were obtained and preserved for analysis of fish health and reproductive biomarkers. Whole fish from each station were composited by species and gender and analyzed for organochlorine chemical residues and elemental contaminants using instrumental methods, and for 2,3,7,8-tetrachloro dibenzo-p-dioxin-like activity (TCDD-EQ) using the H4IIE rat hepatoma cell bioassay. Overall, fish from lower RGB stations contained greater concentrations of organochlorine pesticide residues and appeared to be less healthy than those from sites in the central and upper parts of the basin, as indicated by a general gradient of residue concentrations and biomarker responses. A minimal number of altered biomarkers and few or no elevated contaminant concentrations were noted in fish from the upper RGB. The exception was elevated concentrations [up to 0.46 ??g/g wet-weight (ww)] of total mercury (Hg) in predatory species from the Rio Grande at Elephant Butte Reservoir, NM, a condition documented in previous studies. Arsenic (As) and selenium (Se) concentrations were greatest in fish from sites in the central RGB; Se concentrations in fish from the Pecos River at Red Bluff Lake, TX and from the Rio Grande at Langtry, TX and Amistad International Reservoir, TX exceeded published fish and wildlife toxicity thresholds. In the lower RGB, residues of p,p???-DDT metabolites (???1.69 ??g/g ww), chlordane-related compounds (???0.21 ??g/g ww), dieldrin (???0.0.05 ??g/g ww), and toxaphene (???2.4 ??g/g ww) were detected in fish from most sites; maximum concentrations were in channel catfish (Ictalurus punctatus) from the Arroyo Colorado at Harlingen, TX. Concentrations of one or more residues exceeded toxicity thresholds for fish and wildlife in fish from this site and from the Rio Grande at Mission, TX and Brownsville, TX; however, concentrations were lower than those reported by previous studies. In addition, the proportional concentrations of p,p???-DDT at all sites were low, indicating weathered DDT rather than the influx of new material. Concentrations of total PCBs (<0.05 ??g/g ww) and TCDD-EQ (???6 pg/g ww) were comparatively low in all samples. Hepatic ethoxyresorufin O-deethylase (EROD) activity in some fish was elevated relative to reference rates at most sites, but was generally lower than previously reported activity in fish from heavily contaminated locations. The comparatively low PCB and TCDD-EQ concentrations together with elevated EROD activity may reflect exposure to polycyclic aromatic hydrocarbons. Reproductive biomarkers were consistent with chronic contaminant exposure at lower RGB sites; comparatively large percentages of intersex male largemouth bass, relatively low gonadosomatic indices, and elevated plasma vitellogenin concentrations in male fish were noted at three of the four stations. Large percentages of atretic eggs were also observed in the ovaries of female common carp from the Rio Grande at Brownsville, TX. Although many of the conditions noted may have other causes in addition to contaminant exposure, the biomarker results for the lower RGB sites are consistent with subtle responses of fish to contaminants, an interpretation supported by the chemical data of this and other investigations.

Science of the Total Environment↗

USGS2000

Generalized surficial geologic map of the Denver 1° x 2° quadrangle, Colorado

Thirty-nine types of surficial geologic deposits and residual materials of Quaternary age are described and mapped in the greater Denver area, in part of the Front Range, and in the piedmont and plains east of Denver, Boulder, and Castle Rock. Descriptions appear in the pamphlet that accompanies the map. Landslide deposits, colluvium, residuum, alluvium, and other deposits or materials are described in terms of predominant grain size, mineral or rock composition (e.g., gypsiferous, calcareous, granitic, andesitic), thickness of deposits, and other physical characteristics. Origins and ages of the deposits and geologic hazards related to them are noted. Many lines between geologic units on our map were placed by generalizing contacts on published maps. However, in 1997-1999 we mapped new boundaries, as well. The map was projected to the UTM projection. This large map area extends from the Continental Divide near Winter Park and Fairplay (on the west edge), eastward about 107 mi (172 km); and extends from Boulder on the north edge to Woodland Park at the south edge (68 mi; 109 km).

Colorado↗

USGS1995

Modeling and predicting intertidal variations of the salinity field in the Bay/Delta

San Francisco Bay and the Sacramento/San Joaquin Delta have challenged estuarine modelers for some years. Accurate, broad-scale models of this estuary have been in demand by those concerned with its ecological health and the development of sound management policies. A description and better understanding of the dynamics that govern the bay/delta are complicated by the system's complexity, requiring models that are sophisticated enough to capture the subtle physical processes involved. One approach to simulating daily to monthly variability in the bay is the development of intertidal model using tidally-averaged equations and a time step on the order of the day. An intertidal numerical model of the bay's physics, capable of portraying seasonal and inter-annual variability, would have several uses. Observations are limited in time and space, so simulation could help fill the gaps. Also, the ability to simulate multi-year episodes (eg, an extended drought) could provide insight into the response of the ecosystem to such events. Finally, such a model could be used in a forecast mode wherein predicted delta flow is used as model input, and predicted salinity distribution is output with estimates days and months in advance. This note briefly introduces such a tidally-averaged model (Uncles and Peterson, in press) and a corresponding predictive scheme for baywide forecasting.

California↗

USGS2026

Living with wildfire in Lake County, Colorado: 2023 Data report

Homeowner wildfire risk mitigation and preparedness are important components of community wildfire readiness. This report describes the data collected through two efforts conducted in the Lake County, Colorado, study area: (1) parcel-level rapid wildfire risk assessments performed by trained assessors and (2) homeowner surveys in which respondents provided self-assessments of their parcel-level wildfire risk. This project was undertaken to support Colorado State Forest Service Salida Field Office and Leadville/Lake County Fire-Rescue. The household surveys explored the social dimensions of wildfire, including understanding of wildfire risk, outreach or communication preferences, mitigation and evacuation preparedness activities, and perceptions of community risk reduction strategies. Overall, the study results detail a community that was engaged in preparing for and mitigating the risk of wildfire while revealing more that could be done to reduce risk.

Colorado↗

USGS1960

Wetland and water supply

The Geological Survey has received numerous inquiries about the effects of proposed changes in the wetland environment. The nature of the inquiries suggests a general confusion in the public mind as to wetland values and an increasing concern by the public with the need for facts as a basis for sound decisions when public action is required. Perhaps the largest gap in our knowledge is in regard to the role played by the wetland in the natural water scheme. Specialists in such fields as agriculture and conservation have studied the wetland in relation to its special uses and values for farming and as a habitat for fish and wildlife. However, except as studied incidentally by these specialists, the role of the wetland with respect to water has been largely neglected. This facet of the wetland problem is of direct concern to the Geological Survey. We commonly speak of water in terms of its place in the hydrologic environment---as, for example, surface water or ground water. These terms imply that water can be neatly pigeonholed. With respect to the wetland environment nothing can be further from the truth. In fact, one objective of this discussion is to demonstrate that for the wetland environment surface water, ground water, and soil water cannot be separated realistically, but are closely interrelated and must be studied together. It should be noted that this statement holds true for the hydrologic environment in general, and that the wetland environment is by no means unique in this respect. Our second and principal objective is to identify some of the problems that must be studied in order to clarify the role of the wetland in relation to water supply. We have chosen to approach these objectives by briefly describing one area for which we have some information, and by using this example to point out some of the problems that need study. First, however, let us define what we, as geohydrologists, mean by wetland and briefly consider wetland classifications. For our purpose wetlands are land areas that are covered with shallow water or subjected to intermittent flooding and subsequent slow drainage, and which generally are characterized by an accumulation of organic matter hereafter termed swamp deposits.' These wetlands may be classified in a number of different ways depending on the purpose of the classifier. For example, the Fish and Wildlife Service classifies wetlands into 20 different types based on water quality (fresh or salty), drainage, and vegetation. At the risk of some oversimplification we might consider 4 types of wetland from the standpoint of hydrology: (1) fresh-water swamps in which the swamp deposits are underlain by glacial till or bedrock; (2)fresh-water swamps in which the swamp deposits are underlain by marine or lacustrine clay and silt; (3) fresh-water swamps in which the swamp deposits are underlain by glacial outwash or alluvium consisting mostly of sand or sand and gravel; and (4) salt .marshes and salt meadows. The three fresh-water types of wetland are of interest with respect to water supply, and of these, the type in which swamp deposits are underlain by glacial outwash is of particular interest in New England. In the Ipswich River basin above the Geological Survey gaging station at South Middleton, Mass., is an area of 44 square miles which forms the headwaters section of the basin. The relief of the area is low. About half the area consists of hills mostly underlain by bedrock but mantled by a thin layer of glacial till. The other half consists Of lowlands---including swamps, low terraces and plains---underlain by glacial outwash, Swampland, used hereafter as a synonym for wetland, forms about a fourth of the area. Some of the swamps occupy depressions in the till blanket and are situated at somewhat higher levels than the lowlands. The largest swamps, however, border the Ipswich River and its tributaries. Here the swamp deposits, which consist of muck and peat mixed with s

Circular↗

USGS2013

Regional bankfull-channel dimensions of non-urban wadeable streams in Indiana

During floods, damage to properties and community infrastructure may result from inundation and the processes of erosion. The damages imparted by erosion are collectively termed the fluvial erosion hazard (FEH), and the Indiana Silver Jackets Multi-agency Hazard Mitigation Taskforce is supporting a program to build tools that will assist Indiana property owners and communities with FEH-mitigation efforts. As part of that program, regional channel-dimension relations are identified for non-urban wadeable streams in Indiana. With a site-selection process that targeted the three largest physiographic regions of the state, field work was completed to measure channel-dimension and channel-geometry characteristics across Indiana. In total, 82 sites were identified for data collection; 25 in the Northern Moraine and Lake region, 31 in the Central Till Plain region, and 26 in the Southern Hills and Lowlands region. Following well established methods, for each data-collection site, effort was applied to identify bankfull stage, determine bankfull-channel dimensions, and document channel-geometry characteristics that allowed for determinations of channel classification. In this report, regional bankfull-channel dimension results are presented as a combination of plots and regression equations that identify the relations between drainage area and the bankfull-channel dimensions of width, mean depth, and cross-sectional area. This investigation found that the channel-dimension data support independent relations for each of the three physiographic regions noted above. Furthermore, these relations show that, for any given drainage area, northern Indiana channels have the smallest predicted dimensions, southern Indiana channels have the largest predicted dimensions, and central Indiana channels are intermediate in their predicted dimensions. When considering the suite of variables that influence bankfull-channel dimensions, it appears that contrasting runoff characteristics between the three physiographic regions may explain much of the inequality observed in the measured channel dimensions. While this investigation targeted non-urban wadeable streams in Indiana, site conditions prevented data collection in some areas. Therefore, application of the results of this study always should include knowledge gained from local observations.

Indiana↗

USGS1986

Map of Western Copper River Basin, Alaska, Showing Lake Sediments and Shorelines, Glacial Moraines, and Location of Stratigraphic Sections and Radiocarbon-Dated Samples

The purpose of this report is to make available basic data on radiocarbon dating of 61 organic samples from 40 locations in the western Copper River Basin and adjacent uplands and in the uppermost Matanuska River Valley. The former distribution of late Quaternary glacial lakes and of glaciers as mapped from field work and photo interpretation is provided as background for interpretation of the radiocarbon dates and are the basic data needed for construction of the late Quaternary chronology. The glacial boundaries, formed and expressed by moraines, ice-contact margins, marginal channels, deltas, and other features, are obscured by a drape of glaciolacustrine deposits in a series of glacial lakes. The highest lake, represented by bottom sediments as high as 914 m to 975 m above sea level, extends from Fog Lakes lowland on Susitna River upstream into the northwestern part of the Copper River Basin (the part now draining to Susitna River) where it apparently was held in by an ice border. It was apparently dammed by ice from the Mt. McKinley area, by Talkeetna G1acier, and may have had a temporary drainage threshold at the headwaters of Chunilna Creek. No shorelines have been noted within the map area, although Nichols and Yehle (1961) reported shorelines within the 914-975 m range in the Denali area to the north of that mapped. Recent work by geologic consultants for the Susitna Hydroelectric Project has confirmed the early inferences (Karlstrom, 1964) about the existence of a lake in the Susitna canyon, based originally on drilling by the Bureau of Reclamation about 35 years ago. According to dating of deposits at Tyone Bluff (map locations 0, P), Thorson and others (1981) concluded that a late Wisconsin advance of the glaciers between 11,535 and 21,730 years ago was followed by a brief interval of lacustrine sedimentation, and was preceded by a long period of lake deposition broken by a lowering of the lake between 32,000 and about 25,000 years ago. An alternate interpretation of the late Wisconsin till at Tyone Bluff is that it is a glaciolacustrine diamicton of the 914-975 m lake into which the ice advanced to the Hatchet Lake and to the Old Man moraines. The level of this regional lake in the Susitna drainage and on Heartland Ridge then dropped from over 914 m to about 777 m, to uncover the Tyone Spillway. An intermediate lake level in the Susitna-Tyone-Louise lake region was lowered rapidly by erosion of the spillway to 747 m. The drainage of the 747 m lake was concentrated in the spillway leading west from the West Fork Gulkana River. This spillway or a rock threshold downstream apparently was stable enough to permit formation of basin-wide, apparently undeformed, shoreline systems at 747 m, and, on recession, local shorelines at 717 m and 700 m and lower levels. The level of the 747 m lake that was confined to about 9000 km2 of the present Copper River Basin fluctuated for one or more reasons such as: the volume of ice added to or withdrawn from the system, because of changes in water budget (assuming no outflow), and/or because of temporary releases through the only outlets, perhaps Mentasta Pass, but importantly, the Copper River canyon. The 747 m lake persisted until glaciers had withdrawn to well within the Chugach Mountains, perhaps 10 to 20 km from the present glaciers.

Open-File Report↗

USGS2021

Living with wildfire in Chalk Creek, Chaffee County, Colorado: 2019 data report

Wildfire affects many types of communities and is a particular concern for communities in the wildland urban interface (WUI), such as Chalk Creek in Chaffee County. The core intent of this project was to provide evidence to support Colorado State Forest Service (CSFS) Salida Field Office’s wildfire mitigation and education program. This report analyzes existing wildfire risk data collected in late 2017 through 2019 and pairs it with social data collected in the summer of 2019, in order to better understand Chalk Creek residents’ knowledge, experiences, and perceptions about wildfire risk. This greater understanding will help CSFS focus its programs and outreach and ultimately promote increased mitigation and reduced wildfire risk in Chalk Creek.

Colorado↗

USGS1992

The Galileo Solid-State Imaging experiment

The Solid State Imaging (SSI) experiment on the Galileo Orbiter spacecraft utilizes a high-resolution (1500 mm focal length) television camera with an 800 ?? 800 pixel virtual-phase, charge-coupled detector. It is designed to return images of Jupiter and its satellites that are characterized by a combination of sensitivity levels, spatial resolution, geometric fiedelity, and spectral range unmatched by imaging data obtained previously. The spectral range extends from approximately 375 to 1100 nm and only in the near ultra-violet region (??? 350 nm) is the spectral coverage reduced from previous missions. The camera is approximately 100 times more sensitive than those used in the Voyager mission, and, because of the nature of the satellite encounters, will produce images with approximately 100 times the ground resolution (i.e., ??? 50 m lp-1) on the Galilean satellites. We describe aspects of the detector including its sensitivity to energetic particle radiation and how the requirements for a large full-well capacity and long-term stability in operating voltages led to the choice of the virtual phase chip. The F/8.5 camera system can reach point sources of V(mag) ??? 11 with S/N ??? 10 and extended sources with surface brightness as low as 20 kR in its highest gain state and longest exposure mode. We describe the performance of the system as determined by ground calibration and the improvements that have been made to the telescope (same basic catadioptric design that was used in Mariner 10 and the Voyager high-resolution cameras) to reduce the scattered light reaching the detector. The images are linearly digitized 8-bits deep and, after flat-fielding, are cosmetically clean. Information 'preserving' and 'non-preserving' on-board data compression capabilities are outlined. A special "summation" mode, designed for use deep in the Jovian radiation belts, near Io, is also described. The detector is 'preflashed' before each exposure to ensure the photometric linearity. The dynamic range is spread over 3 gain states and an exposure range from 4.17 ms to 51.2 s. A low-level of radial, third-order, geometric distortion has been measured in the raw images that is entirely due to the optical design. The distortion is of the pincushion type and amounts to about 1.2 pixels in the corners of the images. It is expected to be very stable. We discuss the measurement objectives of the SSI experiment in the Jupiter system and emphasize their relationships to those of other experiments in the Galileo project. We outline objectives for Jupiter atmospheric science, noting the relationship of SSI data to that to be returned by experiments on the atmospheric entry Probe. We also outline SSI objectives for satellite surfaces, ring structure, and 'darkside' (e.g., aurorae, lightning, etc.) experiments. Proposed cruise measurement objectives that relate to encounters at Venus, Moon, Earth, Gaspra, and, possibly, Ida are also briefly outlined. The article concludes with a description of a 'fully distributed' data analysis system (HIIPS) that SSI team members intend to use at their home institutions. We also list the nature of systematic data products that will become available to the scientific community. Finally, we append a short 'historical' note outlining the responsibilities and roles of institutions and individuals that have been involved in the 14 year development of the SSI experiment so far. ?? 1992 Kluwer Academic Publishers.

Space Science Reviews↗

USGS1979

Water resources of the St. Louis River watershed, northeastern Minnesota

The St. Louis River is the largest tributary to Lake Superior in Minnesota. It drains a predominantly forested area of about 3,650 mi 2 (Minnesota Department of Conservation, 1959) and discharges into the lake at Duluth. The Mesabi Iron Range, noted for rich deposits of iron ore, parallels much of the northern watershed boundary. Large areas of land were altered by mining activities, as seen on the Landsat-1 MSS 7 images for September 26, 19744 (No. 1795-16203). The northeastward-trending string of water bodies along the northern boundary are flooded mine pits and tailings basins. The northeastern part of the watershed is largely State and National forest, whereas much of the southwestern and central parts are peat-covered wetlands. Generalized topographic features are shown on the map above. The topographic high along the northern boundary includes the Iron Range and is dissected by post-glacial drainage. The most notable drainage gap is that occupied by the Embarrass River. The series of southwestward-trending elongate hills in the eastern part of the watershed, visible on both the Landsat image and the topographic map, is the Toimi Drumlin Field (Wright, 1972). Topographically low, relatively flat land in the southwestern and central parts is a glacial lake plain. St. Louis River gradients are highly variable, being 9 ft/mi from its headwaters to the mouth of Partridge River, slightly more than 1 ft/mi from Partridge River to Cloquet, and 35 to 40 ft/mi in a 15-mi reach below Cloquest. The watershed is sparsely settled except for its northern and south-eastern parts. About 80 percent of the urban population lives on the Iron Range. Most of the suburban and rural residents alro live on or near the range or in the southeastern part of the watershed. Total population (1970), exclusive of those in the city of Duluth, which is included in the Lake Superior watershed (Olcott and others, 1976), was about 117,000.

Minnesota↗

USGS2021

Borehole analysis, single-well aquifer testing, and water quality for the Burnpit well, Mount Rushmore National Memorial, South Dakota

Mount Rushmore National Memorial (hereafter referred to as “the memorial”), in western South Dakota, is maintained by the National Park Service (NPS) and includes 1,278 acres of land in the east-central part of the Black Hills. An ongoing challenge for NPS managers at the memorial is providing water from sustainable and reliable sources for operations, staff, and the increasing number of visitors. In 2020, the U.S. Geological Survey (USGS) and NPS completed a hydrological study of the Burnpit well (well 5), a 580-foot-deep open hole groundwater well completed in metamorphic (crystalline) rock at the memorial. The purpose of this study was to estimate the geological and hydraulic properties of the aquifer supplying the well and to determine the water quality of the groundwater from the well. The study provides NPS staff and managers background information for assessing future uses for the well. Methods for data collection and analysis for the study included borehole and video camera analysis in 2020, aquifer testing by the NPS in 2009 and the USGS in 2020, and water-quality sampling in 2020. Borehole camera video generally matched the lithology recorded in the well log. Fractures recorded in the well log and observed with the borehole camera, including more than 20 less prominent fractures and rough sidewall areas, indicated a fractured aquifer. The fractures are the primary conduits for groundwater flow through the rock and into the well. Transmissivity was estimated for the upper and lower water-level drawdown zones at the Burnpit well with data from the NPS and USGS using the Theis and Cooper-Jacob methods. Transmissivity for the NPS test using the Theis method was 9.0 and 11 feet squared per day (ft 2 /d) for the upper and lower drawdown zones, respectively. Using the Cooper-Jacob method, the transmissivity was 22 and 14 ft 2 /d for the upper and lower drawdown zones of the aquifer, respectively. Transmissivity estimates from data from the USGS test were similar. The Theis method, applied to the upper and lower drawdown zones of the aquifer, produced transmissivity estimates of 7.7 and 10 ft 2 /d, and the Cooper-Jacob method produced estimates of 9.7 and 12 ft 2 /d, respectively. Storativity (specific yield) estimated using the Theis method for the NPS aquifer-test data was 0.85 and 0.92 for the upper and lower drawdown zones of the aquifer, respectively. The Cooper-Jacob method applied to the NPS aquifer-test data produced storativity estimates of 0.11 and 0.50 for the upper and lower drawdown zones, respectively. The Theis method applied to the USGS aquifer-test data estimated storativity values of 0.77 and 1.0 for the upper and lower drawdown zones, respectively. The Cooper-Jacob method estimated storativity of 0.50 and 0.60 for the upper and lower drawdown zones of the USGS aquifer test, respectively. The estimated storativity values from the NPS and USGS aquifer tests for the upper and lower drawdown zones were higher than expected for limestones and schists. The hypothetical equilibrium drawdown for the Burnpit well was estimated after the NPS test in 2009 at no more, and possibly less, than 35 gallons per minute. The NPS noted that the sustainable yield likely was overestimated because the water level did not stabilize during the NPS aquifer test. The specific capacity for the NPS aquifer test in 2009 was 0.16 gallon per minute per foot ([gal/min]/ft) of drawdown at 3 hours, and the specific capacity for the USGS aquifer test in 2020 was 0.13 (gal/min)/ft of drawdown at 3 hours. The rate of water-level recovery after pumping ceased was 0.017 and 0.013 (gal/min)/ft for the NPS and USGS aquifer tests, respectively. The water-level recovery rate was nearly an order of magnitude less than the specific capacity estimated during pumping, indicating that water levels in the Burnpit well may not recover quickly enough during pumping to provide for a continuous source of water. Water-quality samples were collected at the Burnpit well on June 24 and July 23, 2020, and analyzed for field-measured properties, major ions, metals, nutrients, and perchlorate. Iron, zinc, and lithium concentrations for unfiltered samples in the well were at least three times greater than the mean filtered sample concentrations reported for crystalline aquifers in the Black Hills. Manganese concentrations were less than the mean concentration for crystalline aquifers but exceeded the U.S. Environmental Protection Agency (EPA) secondary drinking-water standards. The iron concentration from the June 24 sample was about 11 times greater than the EPA secondary drinking-water standards and mean concentrations from crystalline aquifers in the Black Hills. Arsenic concentrations in Burnpit well samples collected in 2020 were greater than the EPA primary drinking-water standard and the mean concentration for crystalline aquifers in the Black Hills. Arsenic occurs naturally in the rock of crystalline aquifers, and concentrations from samples in the Black Hills commonly exceed the EPA primary drinking-water standard of 10 micrograms per liter. High concentrations of arsenic, iron, and manganese metals in the Burnpit well make groundwater from the well in its natural state unusable as a drinking-water source, and water treatment would be necessary to reduce the trace element concentrations to less than the EPA primary and secondary drinking-water standards. However, if the memorial has immediate nonpotable water requirements, such as for construction and fire suppression, groundwater from the Burnpit well could provide water without causing additional stress to current (2021) drinking-water sources.

South Dakota↗

USGS2016

Stratigraphic architecture of a fluvial-lacustrine basin-fill succession at Desolation Canyon, Uinta Basin, Utah: Reference to Walthers’ Law and implications for the petroleum industry

A continuous window into the fluvial-lacustrine basin-fill succession of the Uinta Basin is exposed along a 48-mile (77-kilometer) transect up the modern Green River from Three Fords to Sand Wash in Desolation Canyon, Utah. In ascending order the stratigraphic units are: 1) Flagstaff Limestone, 2) lower Wasatch member of the Wasatch Formation, 3) middle Wasatch member of the Wasatch Formation, 4) upper Wasatch member of the Wasatch Formation, 5) Uteland Butte member of the lower Green River Formation, 6) lower Green River Formation, 7) Renegade Tongue of the lower Green River Formation, 8) middle Green River Formation, and 9) the Mahogany oil shale zone marking the boundary between the middle and upper Green River Formations. This article uses regional field mapping, geologic maps, photographs, and descriptions of the stratigraphic unit including: 1) bounding surfaces, 2) key upward stratigraphic characteristics within the unit, and 3) longitudinal changes along the river transect. This information is used to create a north-south cross section through the basin-fill succession and a detailed geologic map of Desolation Canyon. The cross section documents stratigraphic relationships previously unreported and contrasts with earlier interpretations in two ways: 1) abrupt upward shifts in the stratigraphy documented herein, contrast with the gradual interfingering relationships proposed by Ryder et al., (1976) and Fouch et al., (1994) , 2) we document fluvial deposits of the lower and middle Wasatch to be distinct and more widespread than previously recognized. In addition, we document that the Uteland Butte member of the lower Green River Formation was deposited in a lacustrine environment in Desolation Canyon. Two large-scale (member-scale) upward patterns are noted: Waltherian, and non-Waltherian. The upward successions in Waltherian progressions record progradation or retrogradation of a linked fluvial-lacustrine system across the area; whereas the upward successions in non-Waltherian progressions record large-scale changes in the depositional system that are not related to progradation or retrogradation of the ancient lacustrine shoreline. Four Waltherian progressions are noted: 1) the Flagstaff Limestone to lower Wasatch Formation member records the upward transition from lacustrine to fluvial—or shallowing-upward succession; 2) the upper Wasatch to Uteland Butte records the upward transition from fluvial to lacustrine—or a deepening upward succession; 3) the Uteland Butte to Renegade Tongue records the upward transition from lacustrine to fluvial—a shallowing-upward succession; and 4) the Renegade Tongue to Mahogany oil shale interval records the upward transition from fluvial to lacustrine—a deepening upward succession. The two non-Waltherian progressions in the study area are: 1) the lower to middle Wasatch, which records the abrupt shift from low to high net-sand content fluvial system, and 2) the middle to upper Wasatch, which records the abrupt shift from high to intermediate net-sand content fluvial system.

Utah↗