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USGS2011

U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center-fiscal year 2010 annual report

The Earth Resources Observation and Science (EROS) Center is a U.S. Geological Survey (USGS) facility focused on providing science and imagery to better understand our Earth. The work of the Center is shaped by the earth sciences, the missions of our stakeholders, and implemented through strong program and project management, and application of state-of-the-art information technologies. Fundamentally, EROS contributes to the understanding of a changing Earth through 'research to operations' activities that include developing, implementing, and operating remote-sensing-based terrestrial monitoring capabilities needed to address interdisciplinary science and applications objectives at all levels-both nationally and internationally. The Center's programs and projects continually strive to meet, and where possible exceed, the changing needs of the USGS, the Department of the Interior, our Nation, and international constituents. The Center's multidisciplinary staff uses their unique expertise in remote sensing science and technologies to conduct basic and applied research, data acquisition, systems engineering, information access and management, and archive preservation to address the Nation's most critical needs. Of particular note is the role of EROS as the primary provider of Landsat data, the longest comprehensive global land Earth observation record ever collected. This report is intended to provide an overview of the scientific and engineering achievements and illustrate the range and scope of the activities and accomplishments at EROS throughout fiscal year (FY) 2010. Additional information concerning the scientific, engineering, and operational achievements can be obtained from the scientific papers and other documents published by EROS staff or by visiting our web site at http://eros.usgs.gov. We welcome comments and follow-up questions on any aspect of this Annual Report and invite any of our customers or partners to contact us at their convenience. To communicate with us, or for more information about EROS, contact: Communications and Outreach, USGS EROS Center, 47914 252nd Street, Sioux Falls, South Dakota 57198, jsnelson@usgs.gov, http://eros.usgs.gov/.

Open-File Report↗
USGS2008

Water-level altitudes 2008 and water-level changes in the Chicot, Evangeline, and Jasper Aquifers and compaction 1973-2007 in the Chicot and Evangeline Aquifers, Houston-Galveston Region, Texas

This report, done in cooperation with the Harris-Galveston Subsidence District, the City of Houston, the Fort Bend Subsidence District, and the Lone Star Groundwater Conservation District, is one in an annual series of reports that depicts water-level altitudes and water-level changes in the Chicot, Evangeline, and Jasper aquifers, and compaction in the Chicot and Evangeline aquifers in the Houston-Galveston region, Texas. The report contains 17 sheets and 16 tables: 3 sheets are maps showing current-year (2008) water-level altitudes for each aquifer, respectively; 3 sheets are maps showing 1-year (2007-08) water-level changes for each aquifer, respectively; 3 sheets are maps showing 5-year (2003-08) water-level changes for each aquifer, respectively; 4 sheets are maps showing long-term (1990-2008 and 1977-2008) water-level changes for the Chicot and Evangeline aquifers, respectively; 1 sheet is a map showing long-term (2000-2008) water-level change for the Jasper aquifer; 1 sheet is a revision of a previously published water-level-altitude map for the Jasper aquifer for 2003; 1 sheet is a map showing site locations of borehole extensometers; and 1 sheet comprises graphs showing measured compaction of subsurface material at the sites from 1973 or later through 2007, respectively. Tables listing the data used to construct the aquifer-data maps and the compaction graphs are included.

Texas↗
USGS2017

Lidar-revised geologic map of the Des Moines 7.5' quadrangle, King County, Washington

This map is an interpretation of a modern lidar digital elevation model combined with the geology depicted on the Geologic Map of the Des Moines 7.5' Quadrangle, King County, Washington (Booth and Waldron, 2004). Booth and Waldron described, interpreted, and located the geology on the 1:24,000-scale topographic map of the Des Moines 7.5' quadrangle. The base map that they used was originally compiled in 1943 and revised using 1990 aerial photographs; it has 25-ft contours, nominal horizontal resolution of about 40 ft (12 m), and nominal mean vertical accuracy of about 10 ft (3 m). Similar to many geologic maps, much of the geology in the Booth and Waldron (2004) map was interpreted from landforms portrayed on the topographic map. In 2001, the Puget Sound Lidar Consortium obtained a lidar-derived digital elevation model (DEM) for much of the Puget Sound area, including the entire Des Moines 7.5' quadrangle. This new DEM has a horizontal resolution of about 6 ft (2 m) and a mean vertical accuracy of about 1 ft (0.3 m). The greater resolution and accuracy of the lidar DEM compared to topography constructed from air-photo stereo models have much improved the interpretation of geology, even in this heavily developed area, especially the distribution and relative age of some surficial deposits. For a brief description of the light detection and ranging (lidar) remote sensing method and this data acquisition program, see Haugerud and others (2003).

Washington↗
USGS2004

Estimates of flow duration, mean flow, and peak-discharge frequency values for Kansas stream locations

Streamflow statistics of flow duration and peak-discharge frequency were estimated for 4,771 individual locations on streams listed on the 1999 Kansas Surface Water Register. These statistics included the flow-duration values of 90, 75, 50, 25, and 10 percent, as well as the mean flow value. Peak-discharge frequency values were estimated for the 2-, 5-, 10-, 25-, 50-, and 100-year floods. Least-squares multiple regression techniques were used, along with Tobit analyses, to develop equations for estimating flow-duration values of 90, 75, 50, 25, and 10 percent and the mean flow for uncontrolled flow stream locations. The contributing-drainage areas of 149 U.S. Geological Survey streamflow-gaging stations in Kansas and parts of surrounding States that had flow uncontrolled by Federal reservoirs and used in the regression analyses ranged from 2.06 to 12,004 square miles. Logarithmic transformations of climatic and basin data were performed to yield the best linear relation for developing equations to compute flow durations and mean flow. In the regression analyses, the significant climatic and basin characteristics, in order of importance, were contributing-drainage area, mean annual precipitation, mean basin permeability, and mean basin slope. The analyses yielded a model standard error of prediction range of 0.43 logarithmic units for the 90-percent duration analysis to 0.15 logarithmic units for the 10-percent duration analysis. The model standard error of prediction was 0.14 logarithmic units for the mean flow. Regression equations used to estimate peak-discharge frequency values were obtained from a previous report, and estimates for the 2-, 5-, 10-, 25-, 50-, and 100-year floods were determined for this report. The regression equations and an interpolation procedure were used to compute flow durations, mean flow, and estimates of peak-discharge frequency for locations along uncontrolled flow streams on the 1999 Kansas Surface Water Register. Flow durations, mean flow, and peak-discharge frequency values determined at available gaging stations were used to interpolate the regression-estimated flows for the stream locations where available. Streamflow statistics for locations that had uncontrolled flow were interpolated using data from gaging stations weighted according to the drainage area and the bias between the regression-estimated and gaged flow information. On controlled reaches of Kansas streams, the streamflow statistics were interpolated between gaging stations using only gaged data weighted by drainage area.

Kansas↗
USGS2005

Monitoring the natural attenuation of petroleum in ground water at the former naval complex, Operable Unit A, Adak Island, Alaska, May and June 2003

During May and June 2003, the U.S. Geological Survey installed monitoring wells and collected data to characterize the effectiveness of natural attenuation processes for remediating petroleum-contaminated ground water at Operable Unit A of the former Naval complex on Adak Island, Alaska. In addition, the evidence for petroleum biodegradation in ground water was evaluated at selected petroleum sites, plans for future natural attenuation monitoring were suggested for the selected petroleum sites, and the natural attenuation monitoring strategy for the Downtown area of Adak Island was reviewed and refinements were suggested. U.S. Geological Survey personnel measured water levels and collected ground-water samples from about 100 temporary boreholes and 50 monitoring wells. Most samples were analyzed on-site for concentrations of selected petroleum compounds and natural attenuation parameters such as dissolved oxygen, ferrous iron, and carbon dioxide. The U.S. Geological Survey evaluated the data on-site, selected new monitoring well locations, and installed, developed, and sampled 10 monitoring wells. The review and suggestions for the natural attenuation monitoring strategy focused on how to better achieve monitoring objectives specified in the Record of Decision for Adak Island petroleum sites. To achieve the monitoring objective of verifying that natural attenuation is occurring, the monitoring plans for each monitored natural attenuation site need to include sampling of at least one strategically placed well at the downgradient margin of the contaminant plume margin, preferably where contaminant concentrations are detectable but less than the cleanup level. Collection of natural attenuation parameter data and sampling background wells is no longer needed to achieve the monitoring objective of demonstrating the occurrence of natural attenuation. To achieve the objective of monitoring locations where chemical concentrations exceed specified cleanup levels, at least one natural attenuation well within or immediately downgradient from the contaminant source area at each site needs to be monitored. Achieving the Record of Decision-specified final monitoring objective of estimating the rate of natural attenuation to demonstrate achievement of cleanup levels within 75 years will be problematic. Demonstrating (predicting) achievement of cleanup levels within any timeframe in a technically defensible manner will be difficult to achieve using any type of short-term monitoring and evaluation, and will be particularly difficult to achieve through monitoring and evaluation of dissolved-phase petroleum only. Overall, natural attenuation processes appear to have greatly limited the extent of ground-water contamination at most sites investigated and have limited the risk that petroleum contaminants pose to downgradient receptors. Clarification or refinement of the monitoring objective to demonstrate cleanup within 75 years would be a reasonable prelude to developing a monitoring and data evaluation strategy to meet the objective.

Scientific Investigations Report↗
USGS2005

Questa baseline and premining ground-water quality investigation. 8. Lake-sediment geochemical record from 1960 to 2002, Eagle Rock and Fawn Lakes, Taos County, New Mexico

Geochemical studies of lake sediment from Eagle Rock Lake and upper Fawn Lake were conducted to evaluate the effect of mining at the Molycorp Questa porphyry molybdenum deposit located immediately north of the Red River. Two cores were taken, one from each lake near the outlet where the sediment was thinnest, and they were sampled at 1-cm intervals to provide geochemical data at less than 1-year resolution. Samples from the core intervals were digested and analyzed for 34 elements using ICP–AES (inductively coupled plasma–atomic emission spectrometry). The activity of 137 Cs has been used to establish the beginning of sedimentation in the two lakes. Correlation of the geochemistry of heavy-mineral suites in the cores from both Fawn and Eagle Rock Lakes has been used to develop a sedimentation model to date the intervals sampled. The core from upper Fawn Lake, located upstream of the deposit, provided an annual sedimentary record of the geochemical baseline for material being transported in the Red River, whereas the core from Eagle Rock Lake, located downstream of the deposit, provided an annual record of the effect of mining at the Questa mine on the sediment in the Red River. Abrupt changes in the concentrations of many lithophile and deposit-related metals occur in the middle of the Eagle Rock Lake core, which we correlate with the major flood-of-record recorded at the Questa gage at Eagle Rock Lake in 1979. Sediment from the Red River collected at low flow in 2002 is a poor match for the geochemical data from the sediment core in Eagle Rock Lake. The change in sediment geochemistry in Eagle Rock Lake in the post-1979 interval is dramatic and requires that a new source of sediment be identified that has substantially different geochemistry from that in the pre-1979 core interval. Loss of mill tailings from pipeline breaks are most likely responsible for some of the spikes in trace-element concentrations in the Eagle Rock Lake core. Enrichment of Al 2 O 3 , Cu, and Zn occurred as a result of chemical precipitation of these metals from ground water upstream in the Red River. Comparisons of the geochemistry of the post-1979 sediment core with both mine wastes and with premining sediment from the vicinity of the Questa mine indicate that both are possible sources for this new component of sediment. Existing data have not resolved this enigma.

New Mexico↗
USGS2006

Hydrogeology and simulation of ground-water flow in the Silurian-Devonian aquifer system, Johnson County, Iowa

Bedrock of Silurian and Devonian age (termed the “Silurian-Devonian aquifer system”) is the primary source of ground water for Johnson County in east-central Iowa. Population growth within municipal and suburban areas of the county has resulted in increased amounts of water withdrawn from this aquifer and water-level declines in some areas. A 3-year study of the hydrogeology of the Silurian-Devonian aquifer system in Johnson County was undertaken to provide a quantitative assessment of ground water resources and to construct a ground-water flow model that can be used by local governmental agencies as a management tool. Johnson County is underlain by unconsolidated deposits of Quaternary age and Paleozoic-age bedrock units. The bulk of the Quaternary deposits consists of weathered and unweathered glacial till; however, shallow alluvium and buried sand and gravel deposits also are present. Six bedrock hydrogeologic units are present in Johnson County (oldest to youngest): Maquoketa confining unit, Silurian aquifer, Wapsipinicon Group (aquifer and confining unit), Cedar Valley aquifer, Upper Devonian shale confining unit, and Cherokee confining unit. Although separate aquifers and confining units are described, the Silurian- and Devonian-age units are considered as a single aquifer system. The top of the Silurian-Devonian aquifer system is considered as the top of the Cedar Valley aquifer, where present, and the base of the aquifer system is considered as the top of the Maquoketa confining unit. The hydraulic properties of the rocks that comprise the Silurian-Devonian aquifer system are highly variable as a result of the variable composition of the rocks and the presence of solution features in some of the carbonate-rock units. For the combined Silurian-Devonian aquifer system, specific capacity averages 2.1 gallons per minute per foot of drawdown, transmissivity averages about 580 feet squared per day, and hydraulic conductivity averages 8.3 feet per day. Recharge to the Silurian-Devonian aquifer system in Johnson County is predominantly from infiltration of precipitation to the bedrock. Discharge from the aquifer is primarily to municipal, industrial, and private-development wells. Reliable measurements of the amount of recharge to or discharge from the ground-water system in Johnson County, however, are not available. Altitude of the 1996 potentiometric surface ranged from more than 750 feet above the North American Vertical Datum of 1988 (NAVD88) in northern Johnson County to less than 575 feet above NAVD88 in the central part of the county. A large cone of depression within the potentiometric surface is present in the central part of the county, between Coralville and Iowa City. A large limestone quarry is located near the center of this cone of depression. Ground water generally flows from the northern and western parts of Johnson County either toward the cone of depression in the center of the county or south out of the county. Ground water also flows toward the Cedar River in the northeastern part of the county. A ground-water divide in the northeastern part of the county roughly approximates the surface-water divide between the Iowa River and Cedar River drainages. A numerical ground-water-flow model of the Silurian-Devonian aquifer system in Johnson County was used to test concepts of ground-water flow, to assess the need for additional data, and to evaluate the potential effects of anticipated increased ground-water development and drought. The 1-layer model was calibrated to average 1996 ground-water conditions, which were assumed to approximate steady-state flow conditions. The model also was used to simulate steady-state conditions for 2004, steady-state conditions using anticipated pumping rates for 2025, and potential future drought conditions. The simulated potentiometric surface generally replicated the potentiometric surface for 1996 and 2004 conditions. The calculated root mean squared error values for the 1996 and 2004 simulations were 13.6 and 18.6 feet, respectively. The mean absolute differences between measured and simulated water levels for the 1996 and 2004 simulations were about 11 and 14 feet, respectively. Total model-calculated inflow to the ground-water system for the 1996 simulation was 19.6 million gallons per day (Mgal/d), and the largest model-calculated inflow component was areal recharge (15.1 Mgal/d). Total model-calculated outflow from the ground-water system was 19.7 Mgal/d, and the largest outflow component was discharge to wells (10.5 Mgal/d). Model-calculated water-budget components for the 2004 simulation were similar to the 1996 components. Potential future steady-state conditions were simulated using anticipated 2025 pumping rates. Pumpage both for existing wells and for assumed new wells, based on anticipated population growth in the northern part of the county and for the nearby municipalities, was included in the model. Simulated 2025 pumpage was about 1.5 Mgal/d greater than simulated 2004 pumpage. Simulated steady-state ground-water levels, using anticipated 2025 pumping rates, were lower than 2004 simulated levels throughout the county, and simulated water-level declines ranged from less than 1 foot near the county boundaries to about 11 feet. Potential future drought conditions were simulated by assuming that recharge to the Silurian-Devonian aquifer system is reduced by a factor of 0.75 and that water-supply pumpage is increased by a factor of 1.25 over the anticipated 2025 pumping rates. Overall, simulated water levels for future drought conditions were greater than 5 feet lower than simulated 2004 conditions and were a maximum of about 30 feet lower in the northeastern part of the county. The greatest limitation to the model is the lack of measured or estimated water-budget components for comparison to simulated water-budget components. Because the model is only calibrated to measured water levels, and not to water-budget components, the model results are nonunique. Other model limitations include the relatively coarse grid scale, lack of detailed information on pumpage from the quarry and from private developments and domestic wells, and the lack of separate water-level data for the Silurian- and Devonian-age rocks.

Iowa↗
USGS2006

Analysis of sensitivity of simulated recharge to selected parameters for seven watersheds modeled using the precipitation-runoff modeling system

Recharge is a vital component of the ground-water budget and methods for estimating it range from extremely complex to relatively simple. The most commonly used techniques, however, are limited by the scale of application. One method that can be used to estimate ground-water recharge includes process-based models that compute distributed water budgets on a watershed scale. These models should be evaluated to determine which model parameters are the dominant controls in determining ground-water recharge. Seven existing watershed models from different humid regions of the United States were chosen to analyze the sensitivity of simulated recharge to model parameters. Parameter sensitivities were determined using a nonlinear regression computer program to generate a suite of diagnostic statistics. The statistics identify model parameters that have the greatest effect on simulated ground-water recharge and that compare and contrast the hydrologic system responses to those parameters. Simulated recharge in the Lost River and Big Creek watersheds in Washington State was sensitive to small changes in air temperature. The Hamden watershed model in west-central Minnesota was developed to investigate the relations that wetlands and other landscape features have with runoff processes. Excess soil moisture in the Hamden watershed simulation was preferentially routed to wetlands, instead of to the ground-water system, resulting in little sensitivity of any parameters to recharge. Simulated recharge in the North Fork Pheasant Branch watershed, Wisconsin, demonstrated the greatest sensitivity to parameters related to evapotranspiration. Three watersheds were simulated as part of the Model Parameter Estimation Experiment (MOPEX). Parameter sensitivities for the MOPEX watersheds, Amite River, Louisiana and Mississippi, English River, Iowa, and South Branch Potomac River, West Virginia, were similar and most sensitive to small changes in air temperature and a user-defined flow routing parameter. Although the primary objective of this study was to identify, by geographic region, the importance of the parameter value to the simulation of ground-water recharge, the secondary objectives proved valuable for future modeling efforts. The value of a rigorous sensitivity analysis can (1) make the calibration process more efficient, (2) guide additional data collection, (3) identify model limitations, and (4) explain simulated results.

Scientific Investigations Report↗
USGS2011

Bathymetric surveys at highway bridges crossing the Missouri and Mississippi Rivers near St. Louis, Missouri, 2010

Bathymetric surveys were conducted by the U.S. Geological Survey, in cooperation with the Missouri Department of Transportation, on the Missouri and Mississippi Rivers in the vicinity of 12 bridges at 7 highway crossings near St. Louis, Missouri, in October 2010. A multibeam echo sounder mapping system was used to obtain channel-bed elevations for river reaches ranging from 3,280 to 4,590 feet long and extending across the active channel of the Missouri and Mississippi Rivers. These bathymetric scans provide a snapshot of the channel conditions at the time of the surveys and provide characteristics of scour holes that may be useful in the development of predictive guidelines or equations for scour holes. These data also may be used by the Missouri Department of Transportation to assess the bridges for stability and integrity issues with respect to bridge scour. Bathymetric data were collected around every pier that was in water, except those at the edge of water or in extremely shallow water, and one pier that was surrounded by a large debris raft. Scour holes were present at most piers for which bathymetry could be obtained, and ranged from 0 to 16 feet deep except at piers on channel banks or those near or embedded in rock dikes. Scour holes observed at the surveyed bridges were examined with respect to frontal slope and shape, and scour holes near railroad bridges in the vicinity of the highway bridges also were examined. Although exposure of parts of foundational support elements was observed at several piers, the exposure likely can be considered minimal compared to the overall substructure that remains buried at these piers. At piers with well-defined scour holes, the frontal slopes of the holes ranged from 1.70 to 2.94 feet per foot (computed as run over rise), which were similar to recommended values in the literature (generally ranging from 1.0 to 2.0), and the shapes of the scour holes were not substantially affected by the movement of sand waves into the holes. Spur dikes near several of the piers caused localized flow disturbances that caused the resultant scour holes to display characteristics of skewed approach flow. The channel bed in the 2010 surveys was as much as 16 feet lower than the channel bed at the time of construction at the two oldest surveyed bridges, and the range varied with age of the structure, indicating the channel-bed elevations have lowered with time. However, other research has indicated the extremely dynamic nature of the channel bed on the Mississippi River. The size of the scour holes observed at the surveyed sites likely was affected by the low to moderate flow conditions on the Missouri and Mississippi Rivers at the time of the surveys. The scour holes likely would be larger during conditions of increased flow. Artifacts of horizontal positioning errors were present in the data, but an analysis of the surveys indicated that most of the bathymetric data have a total propagated error of less than 0.33 foot.

Scientific Investigations Report↗
USGS2014

Steady-state numerical groundwater flow model of the Great Basin carbonate and alluvial aquifer system

This report describes the construction, calibration, evaluation, and results of a steady-state numerical groundwater flow model of the Great Basin carbonate and alluvial aquifer system that was developed as part of the U.S. Geological Survey National Water Census Initiative to evaluate the nation’s groundwater availability. The study area spans 110,000 square miles across five states. The numerical model uses MODFLOW-2005, and incorporates and tests complex hydrogeologic and hydrologic elements of a conceptual understanding of an interconnected groundwater system throughout the region, including mountains, basins, consolidated rocks, and basin fill. The level of discretization in this model has not been previously available throughout the study area. Observations used to calibrate the model are those of water levels and discharge to evapotranspiration, springs, rivers, and lakes. Composite scaled sensitivities indicate the simulated values of discharge to springs, rivers, and lakes provide as much information about model parameters as do simulated water-level values. The model has 176 parameters and little parameter correlation. The simulated equivalents to observations provide enough information to constrain most parameters to smaller ranges than the conceptual constraints, and most parameter values are within reasonable ranges. Model fit to observations, comparison of simulated to conceptual water-level contours, and comparison of simulated to conceptual water budgets indicate this model provides a reasonable representation of the regional groundwater system. Eighty-six percent of the simulated values of water levels in wells are within 119 feet (one standard deviation of the error) of the observed values. Ninety percent of the simulated discharges are within 30 percent of the observed values. Total simulated recharge in the study area is within 10 percent of the conceptual amount; total simulated discharge is the same as conceptual discharge. Comparison of simulated hydraulic heads with the conceptual potentiometric surface indicates that the model accurately depicts major features of the hydraulic-head distribution. The incorporation of new recharge estimates and of mountain springs and streams as model observations creates higher simulated recharge mounds under many mountain ranges and highlights that in many cases, the regional flow paths go around, not through (or under) mountain ranges. Results from the model show that much of the flow in the groundwater system occurs in deeper layers, even though about 86 percent of the discharge occurs in layer 1. Over 95 percent of the recharge moves down from layer 1, and about 25 percent moves down to layer 8. The model was used to delineate six simulated groundwater flow regions that connect recharge areas to discharge areas. The eastern Great Salt Lake and Great Salt Lake Desert model regions contain 75 percent of the groundwater budget, but only 42 percent of the study area. In contrast, the more southern Death Valley and Colorado model regions contain only 12 percent of the groundwater budget, but 37 percent of the study area. Examples of potential use of the model to investigate the groundwater system include (1) the effects of different recharge, (2) different interpretations of the extent or offset of long faults or fault zones, and (3) different conceptual models of the spatial variation of hydraulic properties. The model can also be used to examine the ultimate effects of groundwater withdrawals on a regional scale, to provide boundary conditions for local-scale models, and to guide data collection.

Great Basin↗
USGS2023

User engagement to improve coastal data access and delivery

Executive Summary A priority of the U.S. Geological Survey (USGS) Coastal and Marine Hazards and Resources Program focus on coastal change hazards is to provide accessible and actionable science that meets user needs. To understand these needs, 10 virtual Coastal Data Delivery Listening Sessions were completed with 5 coastal data user types that coastal change hazards data are intended to serve: resource managers, consultants, local planners, State planners, and non-USGS researchers. During these listening sessions, participants revealed challenges to coastal data use including being overwhelmed by too many webtools, having a lack of capacity to search for and understand new information, facing difficulties finding data, and not understanding how to apply data. The specific coastal data and information needs described by participants are also detailed in the report and describe data gaps, a need for simpler tools, data needs that differ across spatial and temporal scales, and more outreach on coastal topics and climate change. Participants also suggested leveraging data across study sites and regions to help improve capacity issues and called for more communication and collaboration among and within Federal agencies. The synthesized information from the Coastal Data Delivery Listening Sessions provided in this report can help the USGS and those working on coastal challenges better understand barriers to coastal information use and the exact data requirements of different coastal data users.

Scientific Investigations Report↗
USGS2026

Evaluating chlorophyll fluorescence sensors as a proxy for chlorophyll a concentrations in the Illinois River, Illinois, water years 2018–24

The U.S. Geological Survey deployed instream chlorophyll fluorescence sensors on the Illinois River in Illinois to better understand the formation, dynamics, and persistence of riverine algal blooms. At five sensor locations across four U.S. Geological Survey streamgages, chlorophyll fluorescence (fChl) sensors were set to measure instantaneous fChl in micrograms per liter as chlorophyll at 15-minute intervals. These sensors estimate fChl based on the fluorescence response of algal pigments but do not directly measure chlorophyll a (Chl) concentrations or algal biomass. To evaluate the reliability of fChl as a proxy for Chl, fChl measurements were compared to laboratory-measured Chl concentrations. These Chl concentrations were obtained from water-quality samples collected at the sensor locations and analyzed using the standard chromatographic-fluorometric method with acetone extraction. A total of 209 paired fChl and Chl observations were analyzed using Pearson’s correlation and model II regression. Statistically significant, positive correlations (Pearson’s correlation coefficient of 0.68–0.95) were detected at all sensor locations, indicating that fChl generally tracked with Chl. However, model II regression detected proportional and fixed bias at three of the five locations and proportional bias at another location. At locations with proportional biases, model II regression slopes were less than 1, indicating that fChl increasingly underestimated Chl as concentrations increased; however, paired observations at high Chl concentrations were sparse. Substantial variability in bias was also observed across sensor locations with slopes ranging from 0.43 to 0.93. Overall, the results indicated that fChl correlates well with Chl in the Illinois River, but fChl may not reliably represent Chl concentrations without adjustment. For applications requiring accurate Chl estimates, a sensor location-specific surrogate model could be beneficial. These findings underscore the importance of field validation, consistent sensor placement, and careful interpretation of fChl data, particularly when reported in micrograms per liter.

Illinois, Indiana, Wisconsin↗
USGS2007

Catalog of type specimens of recent Crocodilia and Testudines in the National Museum of Natural History, Smithsonian Institution

The known type specimens of Crocodilia and Testudines in the collection of the Division of Amphibians and Reptiles, National Museum of Natural History, Smithsonian Institution, published through 2006 represent 93 names of taxa. The catalog presents a list of 249 type-specimen records consisting of 39 holotypes, 52 syntypes, 3 lectotypes, 2 neotypes, 132 paratypes, and 21 paralectotypes. The list is arranged alphabetically by family within Crocodilia and Testudines, and alphabetically by genus and species, as described originally within family. Each entry provides both original and current genus and species names, author(s), date of publication, abbreviated type citation, page of original description, and accompanying fi gures and plates (if any), current type status, USNM catalog number, number of specimens, specimen measurement(s), locality, collector, and date collected. Also included for each taxon is the published type locality, type material at other institutions, an etymology, and remarks on corrections or additional data for original type records, changes in type status, and information pertaining to lost, exchanged, or destroyed specimens. An index of scientific names follows the catalog.

Smithsonian Contributions to Zoology↗
USGS1980

Satellite image atlas of glaciers

The US Geological Survey has initiated a project to prepare a satellite image atlas of glaciers with the cooperation of a number of US and international organizations. The atlas will include the geographical distribution of glaciers as well as topics of glaciology and related environmental phenomena using Landsat, NOAA and other satellite data. The primary objectives of the atlas are to provide an inventory of available images of extant glaciers, to demonstrate their scientific value and to serve as the basis of Landsat image maps of glacierized areas.

Antarctica, Svalbard↗
USGS2026

Geologic map of pre-Middle Jurassic basement rocks beneath the Atlantic and Gulf Coastal Plains in Florida

Much of the southeastern United States, including all of Florida, is covered by flat-lying sedimentary strata of the Atlantic and Gulf Coastal Plains which have accumulated since Middle Jurassic time. The pre-Middle Jurassic rocks that underlie these coastal plains in Florida, here collectively referred to as “basement,” are known only from a relatively small number of boreholes. This scientific investigations map presents an interpretation of the basement geology in a 1:1,000,000-scale subsurface geologic map with supporting text, data, and figures. The subsurface mapping methodology integrates petrographic, geochronological, thermochronological, geochemical, and mineralogical analyses of drill cores and cuttings in the context of regional geophysical data. The pre-Middle Jurassic rocks of Florida consist of the Gondwanan (West African) Suwannee terrane which was accreted to Laurentia during the Alleghanian orogeny and subsequently intruded by Permian granites, superposed by early Mesozoic rift basins, and partially overlain by bimodal Jurassic volcanic rocks. The younger basement components, specifically the Southwest Florida volcanic province, North Florida tholeiites, early Mesozoic rift basins, and Alleghanian granitoids, have correlative and contemporaneous units throughout the Appalachian orogen. In contrast, Florida’s older basement rocks, including Paleozoic siliciclastic strata of the Suwannee basin, North Florida volcanic series, Osceola and Gaskin intrusive complexes, and the St. Lucie Metamorphic Complex, have neither surface exposures nor unequivocal correlates. Major structures include early Mesozoic normal faults and northwest-striking transfer zones such as the Jay fault. Many of these faults define the boundaries of subbasins within the South Georgia rift system. Top-of-basement structure contours show gentle arches and embayments that are also recognized in overlying coastal plain strata.

Florida↗
USGS1980

Lunar remote sensing and measurements

Remote sensing and measurements of the Moon from Apollo orbiting spacecraft and Earth form a basis for extrapolation of Apollo surface data to regions of the Moon where manned and unmanned spacecraft have not been and may be used to discover target regions for future lunar exploration which will produce the highest scientific yields. Orbital remote sensing and measurements discussed include (1) relative ages and inferred absolute ages, (2) gravity, (3) magnetism, (4) chemical composition, and (5) reflection of radar waves (bistatic). Earth-based remote sensing and measurements discussed include (1) reflection of sunlight, (2) reflection and scattering of radar waves, and (3) infrared eclipse temperatures. Photographs from the Apollo missions, Lunar Orbiters, and other sources provide a fundamental source of data on the geology and topography of the Moon and a basis for comparing, correlating, and testing the remote sensing and measurements. Relative ages obtained from crater statistics and then empirically correlated with absolute ages indicate that significant lunar volcanism continued to 2.5 b.y. (billion years) ago-some 600 m.y. (million years) after the youngest volcanic rocks sampled by Apollo-and that intensive bombardment of the Moon occurred in the interval of 3.84 to 3.9 b.y. ago. Estimated fluxes of crater-producing objects during the last 50 m.y. agree fairly well with fluxes measured by the Apollo passive seismic stations. Gravity measurements obtained by observing orbiting spacecraft reveal that mare basins have mass concentrations and that the volume of material ejected from the Orientale basin is near 2 to 5 million km 3 depending on whether there has or has not been isostatic compensation, little or none of which has occurred since 3.84 b.y. ago. Isostatic compensation may have occurred in some of the old large lunar basins, but more data are needed to prove it. Steady fields of remanent magnetism were detected by the Apollo 15 and 16 subsatellites, and the lunar dipole field was revised to no more than 6x 10 19 gauss. High-resolution mapping of fields of weak remanent magnetism (to 0.1 gamma) was made possible by the Apollo plasma and energetic-particle experiment. Although the causes of remanent magnetism are poorly understood, correlations with geologic units suggest the results may ultimately have farreaching significance to lunar history. Maria are much less structured by strong surface magnetic anomalies than the highlands. The strongest anomalies are associated with ejecta of farside basins, plains materials filling pre-Imbrian craters, and other old Imbrian to pre-Imbrian units. The high remanent fields could be due to cooling of ejecta units in an ancient magnetic field, lunar regolith maturity, extensive reworking and disruption of a magnetized layer, or simply surface roughness. Orbital geochemical experiments have shown that lunar high lands have larger Al: Si ratios and smaller Mg: Si ratios than maria. These two ratios are inversely related on a regional basis. With the exception of fresh craters, albedo and Al : Si ratios vary directly, showing that compositional differences as well as exposure of fresh materials are responsible for high albedos. Statistically treated data show that geologic contacts and compositional boundaries are concentric and can be roughly matched. Some craters on mare material have penetrated the mare fill, bringing highland-type materials to the surface. Natural radioactivity from thorium, potassium, and uranium is inversely correlated with elevation. Mare regions are enriched in iron, titanium, and magnesium relative to the highlands. Orbital bistatic-radar results provide estimates of surface roughness at two scale lengths (about 30 m and 250 m), which agree with visual estimates of roughness. The dielectric constant of the lunar surface, where sampled, is uniform to 13-cm radar and near 3. Slope frequency distributions measured by the radar vary and

Professional Paper↗
USGS1974

The cartographic and scientific application of ERTS-1 imagery in polar regions

The first Earth Resources Technology Satellite (ERTS-1), launched by the National Aeronautics and Space Administration in. July 1972, is providing valuable data for investigations of the most inaccessible and hostile regions of the Earth the Arctic and Antarctic. ERTS images and map products derived from them offer a whole new dimension in source material for multidiscipline investigations in the earth sciences. For the first time scientists can view synoptic, repetitive scenes of the polar regions in four spectral bands. Ongoing experiments funded by NASA and conducted in the U.S. Geological Survey have demonstrated the feasibility of revising coastlines on maps of Antarctica, detected gross changes in the northern limits of the three largest ice shelves in the world, and led to the discovery of uncharted mountain ranges.

Journal of Research of the U.S. Geological Survey↗