Released January 19, 2021 07:31 EST

2021, Report, New Mexico Water Resources Research Institute Technical Reports

Christopher Kubicki, Kenneth C. Carroll, James C. Witcher, Andrew J. Robertson

A significantly elevated groundwater salinity zone was identified in the southern part of the Mesilla Valley. This investigation characterized the occurrence, spatial extent, and source of the plume of elevated groundwater salinity using a wide range of geochemical and geophysical data and methods.

Released January 15, 2021 12:35 EST

1972, Report

Kenneth R. Taylor

No abstract available.

Released January 15, 2021 12:15 EST

1961, Water Data Report MD-DE-61

U.S. Geological Survey

No abstract available.

Released January 15, 2021 12:10 EST

1962, Water Data Report MD-DE-62

U.S. Geological Survey

No abstract available. 

Released January 15, 2021 12:05 EST

1963, Water Data Report MD-DE-63

U.S. Geological Survey

No abstract available. 

Released January 15, 2021 11:57 EST

2021, Open-File Report 2020-1128

Eric E. Grossman, Lisa Marrack, Nathan R. vanArendonk

Coral reefs worldwide are experiencing rapid degradation in response to climate and land-use change, namely effects of warming sea-surface temperatures, contaminant runoff, and overfishing. Extensive coral bleaching caused by the steady rise of sea-surface temperatures is projected to increase, but our understanding and ability to predict where corals may be most resilient to this effect is limited owing to a lack of knowledge of nearshore habitat conditions and the role of compromised coral health in preconditioning bleaching vulnerability. On high islands and most atolls, fresh to brackish groundwater discharges to the coast through the beach face and seafloor, where it mixes with marine waters and commonly creates cool estuarine nearshore waters that are important to wildlife and ecosystem services that benefit people. Here, we summarize results of a study to evaluate the ecosystem services and effects of groundwater on coral reef health and the potential role of groundwater to maintain cold-water refugia that can buffer corals from thermal stress during temperature maxima. Across 75 kilometers of the west coastline of the Island of Hawaiʻi, paired time-series and discrete measurements of water quality, coral-community and colony size structures, and coral health indicators, including bleaching, at 33 stations grouped into 12 study areas were made from July 2010 to December 2013. The results show that nearshore water temperatures are depressed by groundwater across extensive areas of the nearshore. Persistent cold-water refugia ranging from 1 to 5 degrees Celsius below surrounding marine water temperatures are shown to be associated with identified groundwater inputs. Significant correlations were found between metrics of coral health and water temperature. Because areas of temperature refugia were notable along the west coast of the Island of Hawaiʻi and are identified by ecologists as increasingly important to valued wildlife, improved understanding of groundwater flux to the long-term resilience of coral reefs is likely important. In particular, evaluating the extent that the magnitude and timing of groundwater discharge across the nearshore mitigate thermal bleaching stress may help inform the fate of coral reefs projected to experience rising sea-surface temperatures worldwide.

Released January 15, 2021 11:07 EST

2021, Journal of Wildlife Management (85) 303-323

M. Tim Tinker, Julie L. Yee, Kristin L. Laidre, Brian Hatfield, Michael D. Harris, Joseph Tomoleoni, Tom W. Bell, Emily Saarman, Lilian P Carswell, A. Keith Miles

The recovery of large carnivore species from over‐exploitation can have socioecological effects; thus, reliable estimates of potential abundance and distribution represent a valuable tool for developing management objectives and recovery criteria. For sea otters (Enhydra lutris), as with many apex predators, equilibrium abundance is not constant across space but rather varies as a function of local habitat quality and resource dynamics, thereby complicating the extrapolation of carrying capacity (K) from one location to another. To overcome this challenge, we developed a state‐space model of density‐dependent population dynamics in southern sea otters (E. l. nereis), in which K is estimated as a continuously varying function of a suite of physical, biotic, and oceanographic variables, all described at fine spatial scales. We used a theta‐logistic process model that included environmental stochasticity and allowed for density‐independent mortality associated with shark bites. We used Bayesian methods to fit the model to time series of survey data, augmented by auxiliary data on cause of death in stranded otters. Our model results showed that the expected density at K for a given area can be predicted based on local bathymetry (depth and distance from shore), benthic substrate composition (rocky vs. soft sediments), presence of kelp canopy, net primary productivity, and whether or not the area is inside an estuary. In addition to density‐dependent reductions in growth, increased levels of shark‐bite mortality over the last decade have also acted to limit population expansion. We used the functional relationships between habitat variables and equilibrium density to project estimated values of K for the entire historical range of southern sea otters in California, USA, accounting for spatial variation in habitat quality. Our results suggest that California could eventually support 17,226 otters (95% CrI = 9,739–30,087). We also used the fitted model to compute candidate values of optimal sustainable population abundance (OSP) for all of California and for regions within California. We employed a simulation‐based approach to determine the abundance associated with the maximum net productivity level (MNPL) and propose that the upper quartile of the distribution of MNPL estimates (accounting for parameter uncertainty) represents an appropriate threshold value for OSP. Based on this analysis, we suggest a candidate value for OSP (for all of California) of 10,236, which represents 59.4% of projected K.

Released January 15, 2021 08:05 EST

1971, Water Data Report MD-DE-69-1

U.S. Geological Survey

No abstract available.

Released January 15, 2021 08:05 EST

1970, Water Data Report MD-DE-68-2

U.S. Geological Survey

No abstract available.

Released January 15, 2021 08:05 EST

1969, Water Data Report MD-DE-67-2

U.S. Geological Survey

No abstract available. 

Released January 15, 2021 08:05 EST

1969, Water Data Report MD-DE-67-1

U.S. Geological Survey

No abstract available.

Released January 15, 2021 08:05 EST

1968, Water Data Report MD-DE-66-2

U.S. Geological Survey

No abstract available. 

Released January 15, 2021 07:37 EST

2021, Forest Ecology and Management (480)

Micah Charles Wright, Phillip J. van Mantgem, Nathan L. Stephenson, Adrian Das, Jon Keeley

Released January 14, 2021 15:30 EST

1973, Water Data Report MD-DE-70-2

U.S. Geological Survey

No abstract available. 

Released January 14, 2021 15:25 EST

1970, Water Data Report MD-DE-70-1

U.S. Geological Survey

No abstract available.

Released January 14, 2021 13:35 EST

1972, Water Data Report MD-DE-69-2

U.S. Geological Survey

No abstract available. 

Released January 14, 2021 12:15 EST

2021, Open-File Report 2020-1136

Amanda Booth

Understanding the carbon transport within aquatic environments is crucial to quantifying global and local carbon budgets, yet limited empirical data currently (2021) exist. This report documents methodology and provides data for quantifying the aquatic export of carbon from a cypress swamp within Big Cypress National Preserve and is part of a larger carbon budget study. The U.S. Geological Survey operated two continuous monitoring stations, 022889001 and 022909471, that measured flow volume and water quality within the Big Cypress National Preserve in South Florida from September 2015 to October 2017. Station 022889001 represented the flow into the study area and station 022909471 represented the flow out of the study area. Site-specific regression models were developed by using continuously measured specific conductance and concomitant, discretely collected dissolved organic carbon, dissolved inorganic carbon, and particulate carbon samples to calculate total carbon (TC) concentrations at 15-minute intervals.

Calculated TC concentrations typically increased as flow was decreasing and decreased as flow was increasing. TC loads were calculated by multiplying concentrations and flow volume, and the difference between the load calculations for input/output locations of the swamp flow system was used to determine the aquatic carbon export from the study area.

Calculated monthly TC loads ranged from 0 metric tons in spring 2017 at both stations to 3,145 and 7,821 metric tons in September 2017 at 022889001 and 022909471, respectively. During 2016, the annual loads were 10,479 and 15,243 metric tons at 022889001 and 022909471, respectively. Calculated monthly aquatic TC exports from the study area ranged from −0.7 gram of carbon per square meter in May 2016 to 44.1 grams of carbon per square meter during September 2017. The carbon export from the study area varied monthly, increased as flow increased, and was greatly influenced by Hurricane Irma in September 2017. The aquatic TC export from the Sweetwater Strand study area was 42.0 grams of carbon per square meter per year in 2016, which is substantially (about 15 times) larger than the estimated overall mean riverine carbon export per square meter for the eastern United States; however, it was also less than the monthly export of carbon in September 2017. The monthly aquatic carbon export from the study area in September 2017 alone was greater than the aquatic carbon export from all of 2016, which is largely the result of the substantial increase in flow attributed to Hurricane Irma.

Released January 14, 2021 12:05 EST

1970, Water Data Report MD-DE-68-1

U.S. Geological Survey

No abstract available.

Released January 14, 2021 10:55 EST

2021, Endangered Species Research (44) 11-31

Aimee R. Lang, Peter L. Boveng, L. Quakenbush, K. Robertson, M. Lauf, Karyn D. Rode, H. Ziel, B .L. Taylor

Although Arctic ringed seals Phoca hispida hispida are currently abundant and broadly distributed, their numbers are projected to decline substantially by the year 2100 due to climate warming. While understanding population structure could provide insight into the impact of environmental changes on this subspecies, detecting demographically important levels of exchange can be difficult in taxa with high abundance. We used a next-generation sequencing approach (DArTseq) to genotype ~5700 single nucleotide polymorphisms in 79 seals from 4 Pacific Arctic regions. Comparison of the 2 most geographically separated strata (eastern Bering vs. northeastern Chukchi-Beaufort Seas) revealed a statistically significant level of genetic differentiation (F_ST = 0.001, p = 0.005) that, while small, was 1 to 2 orders of magnitude greater than expected based on divergence estimated for similarly sized populations connected by low (1% yr^-1) dispersal. A relatively high proportion (72 to 88%) of individuals within these strata could be genetically assigned to their stratum of origin. These results indicate that demographically important structure may be present among Arctic ringed seals breeding in different areas, increasing the risk that declines in the number of seals breeding in areas most negatively affected by environmental warming could occur.

Released January 14, 2021 10:30 EST

1968, Water Data Report MD-DE-66-1

U.S. Geological Survey

No abstract available. 

Released January 13, 2021 16:30 EST

2021, Open-File Report 2020-1135

Brian N. Shaffer

The Bureau of Land Management (BLM) requested assistance from the U.S. Geological Survey (USGS) to conduct an assessment study to identify areas that may have economic potential for the future extraction of lignite and leonardite resources in the Williston Basin in North Dakota. The study will be used by the BLM to assist with the preparation of a revised resource management plan for the Williston Basin, in accordance with BLM planning policies.

The assessment of the economic potential of lignite resources required the establishment of criteria defining an economic lignite deposit. In consultation with the BLM, criteria were established to delineate drill holes that contained economic lignite beds. The criteria established are a minimum lignite bed thickness, a minimum cumulative lignite thickness, a maximum cumulative stripping ratio, and a maximum overburden. Likewise, an assessment of the economic potential of leonardite deposits required the establishment of criteria delineating drill holes that contained economic leonardite deposits. The criteria established are a minimum leonardite bed thickness, a minimum cumulative leonardite thickness, and a maximum overburden.

The drill hole data utilized in this study were obtained from the National Coal Resources Data System database and from several coal companies. Data from more than 20,000 drill holes, both proprietary and nonproprietary, were used to compile areas of economic potential for lignite or leonardite.

Areas delineated as having lignite or leonardite resources with economic potential, based on the established criteria, were present in 24 counties in the western portion of North Dakota. Areas of economic potential were delineated using a visual best-fit method without croplines. Areas defined as having economic potential for certain lignite beds or leonardite deposits may extend beyond known croplines in this study.

Stratigraphically, the lignite and leonardite deposits in the Williston Basin in North Dakota are mostly found in the Paleocene Fort Union Formation. Thick (greater than 20 feet) and laterally extensive (greater than 5 square miles) lignite beds are present in the Fort Union Formation throughout the Sentinel Butte and Tongue River Members. Lignite beds are also present in the Ludlow Member of the Fort Union Formation, although they are not as numerous or thick as they are in the overlying Sentinel Butte and Tongue River Members. As a result of lateral facies changes and migrating fluvial channel complexes in the Fort Union Formation, lignite beds of varying thickness occupy different stratigraphic horizons vertically throughout the Williston Basin.

The calculation of volumes for lignite and leonardite resources was not part of the scope of this study requested by the BLM, but a future study by the USGS may involve a comprehensive assessment of lignite resources and reserves in the Williston Basin. This future study could combine geologic data compiled in this study with geologic data from a previously unpublished 2019 assessment study by the USGS in the Williston Basin in eastern Montana. This future USGS study could also include the calculation of volumes for lignite resources and reserves, based on economic models derived using analogs from active mining operations in the Williston Basin and available spot market or contract coal prices.

Released January 13, 2021 15:00 EST

2021, Open-File Report 2020-1113

Michael H. Trippi, Leslie F. Ruppert, Cortland F. Eble, James C. Hower

Coking coal, or metallurgical coal, has been produced in the United States for nearly 200 years. Coking coal is primarily used in the production of coke for use in the steel industry, and for other uses (for example, foundries, blacksmithing, heating buildings, and brewing). Currently, U.S. coking coal is produced in Alabama, Arkansas, Pennsylvania, Virginia , and West Virginia. Historically, coking coal has also been produced in 15 other states (Alaska, Colorado, Georgia, Illinois, Indiana, Kentucky, Maryland, Montana, New Mexico, Ohio, Oklahoma, Tennessee, Utah, Washington, and Wyoming), but currently is not. Coals from the Appalachian, Arkoma, and Illinois basins are Pennsylvanian in age, while coals in Alaska, Colorado, Montana, New Mexico, Utah, Washington, and Wyoming range in age from Early Cretaceous through Eocene.

This Open-File Report presents the geographic locations of current and historical coking coal deposits of the United States, with additional information about recent and historical mining and exploration activities. Chemical, rheological, petrographic, and other criteria for evaluating the coking potential of coals are discussed, and historical data for coking coals in the United States are presented. In addition, new coking coal samples from Alabama, Arkansas, Kentucky, and Oklahoma were collected and analyzed for this report, and the data are presented in multiple tables, including proximate and ultimate analyses; calorific value; sulfur forms; major-, minor-, and trace-element abundances; Free-Swelling Index; Gieseler Plastometer analyses; American Society for Testing and Materials (ASTM) dilatation; coal petrography; and predicted values of Coal Stability Factor and Coal Strength after Reaction with CO₂ (pCSF and pCSR, respectively). Data from previously analyzed coking coal samples in Kentucky, Pennsylvania, Virginia, and West Virginia were supplied by three companies, including results from all the tests listed above, plus oxidation, Hardgrove Grindability Index, and ash fusion (in a reducing environment) temperatures are also presented in tables in the report.

Geographic Information System (GIS) data compiled for this project are available for download for public and private utilization and may be used to create maps for a variety of energy resource studies. These GIS data are in shapefile format, and metadata files are included describing all GIS processing. Additional geographic information about coking coal areas of the United States are also presented in tabular format in the report, including the following: names of coal basins, fields, regions, districts, and areas; coal beds or zones; geographic locations including States, counties, towns, rivers, mountains, etc.; stratigraphic hierarchy and age of the coal-bearing interval; coking characteristics including sulfur content, ash yield, volatile matter, moisture, calorific value, and Free-Swelling Index; coal rank; names of coal mines and coal-mining companies; current and past mining activity; and references for reports about the coal.

Released January 13, 2021 11:02 EST

2021, Environmental Science & Technology

Melissa Lombard, Johnni Daniel, Zuha Jeddy, Lauren Hay, Joseph D. Ayotte

This study assesses the potential impact of drought on arsenic exposure from private domestic wells by using a previously developed statistical model that predicts the probability of elevated arsenic concentrations (>10 μg per liter) in water from domestic wells located in the conterminous United States (CONUS). The application of the model to simulate drought conditions used systematically reduced precipitation and recharge values. The drought conditions resulted in higher probabilities of elevated arsenic throughout most of the CONUS. While the increase in the probability of elevated arsenic was generally less than 10% at any one location, when considered over the entire CONUS, the increase has considerable public health implications. The population exposed to elevated arsenic from domestic wells was estimated to increase from approximately 2.7 million to 4.1 million people during drought. The model was also run using total annual precipitation and groundwater recharge values from the year 2012 when drought existed over a large extent of the CONUS. This simulation provided a method for comparing the duration of drought to changes in the predicted probability of high arsenic in domestic wells. These results suggest that the probability of exposure to arsenic concentrations greater than 10 μg per liter increases with increasing duration of drought. These findings indicate that drought has a potentially adverse impact on the arsenic hazard from domestic wells throughout the CONUS.

Released January 13, 2021 07:09 EST

2021, Environmental Monitoring and Assessment (193)

Kelly Smalling, Jennifer Rowe, Christopher Pearl, Luke R. Iwanowiczl, Carrie E. Givens, Chauncey W. Anderson, Brome Mccreary, Michael J. Adams

Released January 12, 2021 08:14 EST

2021, Journal of Fish and Wildlife Managment

Brian O'Malley, Joseph Schmitt, Jeremy P. Holden, Brian C. Weidel

Released January 12, 2021 07:41 EST

2021, Aquatic Mammals (1) 10-20

Sergio Cobarrubia-Russo, Shannon Barber-Meyer, Guillermo R. Barreto, Alimar Molero-Lizarraga

This study reports historic capture-mark-recapture survival and abundance estimates of common bottlenose dolphins (Tursiops truncatus) based on photo-identification surveys of coastal Venezuela (along the Aragua coast between Turiamo Bay and Puerto Colombia). We used the most recent data available: dolphins identified by unique dorsal fin marks during wet and dry season surveys conducted from 2004 to 2008. Dolphin encounter histories were analyzed in the Closed Capture Robust Design framework, with the top model including random movement, constant survival, and capture-recapture probabilities that varied by secondary periods. Survival of marked adults was estimated at 0.99 (95% CI = 0.97 to 1.00). Population estimates for all adults (marked and unmarked) averaged 31 animals (SD = 13.8), and for all dolphins (all adults and calves), 41 animals (SD = 17.2). Coastal bottlenose dolphins face numerous threats, including ship strikes, oil spills, conflict with recreational and industrial fisheries, other negative human interactions, biotoxins, chemicals, noise, freshwater discharge, and coastal development. Further, small populations are, in general, at increased risk due to reduced resiliency and recovery potential when exposed to such threats and to expected environmental and demographic stochasticity. These historic estimates of abundance and survival are critical for establishing a reference state and indicate a need for ongoing monitoring of the small dolphin population while the Aragua coast is still, as of yet, relatively little impacted by humans. Should coastal development increase (as is the global trend) and/or environmental catastrophes (e.g., harmful algal blooms, hurricanes, and oil spills) occur, these historic estimates will be essential for assessing impacts and guiding management and conservation interventions. Our results show year-round dolphin presence and highlight the Venezuelan coastal–oceanic landscape as an area of both future research and conservation importance.

Released January 12, 2021 07:28 EST

2021, Harmful Algae (101)

Megan E Moriarty, M Tim Tinker, Melissa Miller, Joseph Tomoleoni, Michelle M. Staedler, Jessica A. Fujii, Francesca I. Batac, Erin M. Dodd, Raphael M. Kudela, Vanessa Zubkousky-White, Christine K. Johnson

Released January 12, 2021 06:40 EST

2021, Tectonics

Mauricio Espinoza, Veronica Oliveros, Paulina Vasquez, Laura Giambiagi, Leah E. Morgan, Rodrigo Gonzalez, Luigi Solari, Florencia Bechis

Tectonics inheritance controls the evolution of many orogens. To unravel the role of the Gondwanan heritage (late Paleozoic to Triassic) over the building of the Central Andes in northern Chile (Domeyko Range), we performed detrital U‐Pb zircon and ⁴⁰Ar/³⁹Ar muscovite geochronology along with structural analyses (kinematics and structural balancing). ⁴⁰Ar/³⁹Ar dating of detrital muscovite reveals contrasting cooling histories for the Paleozoic basement of Triassic rift sub‐basins, indicating that NW‐striking crustal structures segmented the Andean forearc since at least the middle Permian, likely related to an accretional fabric developed along SW Gondwana. These structures can be inferred based on scattered faults, gravimetric data, and basement age disruptions. During the Late Triassic, NS‐striking master faults and secondary NW‐ to NNW‐striking faults configured an oblique rift, primarily driven by subduction dynamics. We suggest that along SW Gondwana, the slab‐pull would have controlled the development of subduction‐related rift basins close to the trench whereas Triassic inland rifts were mainly driven by Pangea‐breakup stresses. Compressional tectonics began in the Late Cretaceous, yet the inversion of the Triassic rift would have started during the Eocene with the inception of the metallogenic‐fertile transpressional Domeyko fault system. Thus, the structural style of this range was determined by the architecture of the Triassic rift, where the inversion of deep‐seated faults accounted for west‐vergent thick‐ and thin‐skinned structures. Pre‐Andean NW‐striking structures also accommodated tectonic rotations during the Incaic orogeny (Eocene‐Oligocene) and may delimit the rupture zone of large earthquakes, suggesting an underestimated role of such ancient discontinuities in Andean neotectonics.

Released January 11, 2021 09:18 EST

2021, Book

Kimberli J. Miller

A step-by-step guide to “put a dot on the WHISPers map” by creating an event. Available to users assigned Partner User, Partner Manager, and Partner Administrator roles.

Released January 11, 2021 08:12 EST

2020, Human-Wildlife Interactions (14)

Brian D Peer, Barbara E. Kus, Mary J. Whitfield, Linnea S. Hall, Stephen I Rothstein

Released January 11, 2021 07:43 EST

2021, Geological Society of America Bulletin

Jim E. O'Connor, Joseph F. Mangano, Daniel R. Wise, Joshua R. Roering

Released January 11, 2021 07:11 EST

2021, Wetlands Ecology and Management

Owen P. McKenna, David A. Renton, David M. Mushet, Edward S. DeKeyser

Released January 10, 2021 07:08 EST

2021, Functional Ecology

Savannah A. Rogers, Charlie T. Robbins, Paul D. Mathewson, Anthony M. Carnahan, Frank T. van Manen, Mark A. Haroldson, Warren P. Porter, Taylor R. Rogers, Terrence Soule, Ryan A. Long

1. Heat dissipation limit theory posits that energy available for growth and reproduction in endotherms is limited by their ability to dissipate heat. In mammals, endogenous heat production increases markedly during gestation and lactation, and thus female mammals may be subject to greater thermal constraints on energy expenditure than males. Such constraints likely have important implications for behaviour and population performance in a warming climate. 2. We used a mechanistic simulation model based on the first principles of heat and mass transfer to study thermal constraints on activity (both timing and intensity) of captive female grizzly bears Ursus arctos in current and future climate scenarios. We then quantified the relative importance of regulatory behaviours for maintaining heat balance using GPS telemetry locations of lactating versus non-lactating female bears from Yellowstone National Park, and assessed the degree to which costs of thermoregulation constrained the distribution of sampled bears in space and time. 3. Lactating female bears benefitted considerably more from behavioural cooling mechanisms (e.g. partial submersion in cool water or bedding on cool substrate) than non-lactating females in our simulations; the availability of water for thermoregulation increased the number of hours during which lactating females could be active by up to 60% under current climatic conditions and by up to 43% in the future climate scenario. Moreover, even in the future climate scenario, lactating bears were able to achieve heat balance 24 hr/day by thermoregulating behaviourally when water was available to facilitate cooling. 4. The most important predictor of female grizzly bear distribution in Yellowstone, regardless of reproductive status, was elevation. However, variables associated with the thermal environment were relatively more important for predicting the distribution of lactating than non-lactating female bears. 5. Our results suggest that the costs of heat dissipation, which are modulated by climate, may impose constraints on the behaviour and energetics of large endotherms like grizzly bears, and that access to water for cooling will likely be an increasingly important driver of grizzly bear distribution in Yellowstone as the climate continues to warm.

Released January 09, 2021 23:45 EST

2013, Book chapter, Current perspectives in contaminant hydrology and water resources sustainability

Julia L. Barringer, Zoltan Szabo, Pamela A. Reilly

Paul M. Bradley, editor(s)

Mercury (Hg) has long been identified as an element that is injurious, even lethal, to living organisms. Exposure to its inorganic form, mainly from elemental Hg (Hg(0)) vapor (Fitzgerald & Lamborg, 2007) can cause damage to respiratory, neural, and renal systems (Hutton, 1987; USEPA, 2012; WHO, 2012). The organic form, methylmercury (CH₃Hg⁺; MeHg), is substantially more toxic than the inorganic form (Fitzgerald & Lamborg, 2007). Methylmercury attacks the nervous system and exposure can prove lethal, as demonstrated by well-known incidents such as those in 1956 in Minimata, Japan (Harada, 1995), and 1971 in rural Iraq (Bakir et al., 1973), where, in the former, industrial release of MeHg into coastal waters severely tainted the fish caught and eaten by the local population, and in the latter, grain seed treated with an organic mercurial fungicide was not planted, but eaten in bread instead. Resultant deaths are not known with certainty but have been estimated at about 100 and 500, respectively (Hutton, 1987). Absent such lethal accidents, human exposure to MeHg comes mainly from ingestion of piscivorous fish in which MeHg has accumulated, with potential fetal damage ascribed to high fish diets during their mothers’ pregnancies (USEPA, 2001). Lesser human exposure occurs through ingestion of drinking water (USEPA, 2001), where concentrations of total Hg (THg; inorganic plus organic forms) typically are in the low nanograms-per-liter range, particularly from many groundwater sources, and concentrations at the microgram-per-liter level are rare.

Released January 09, 2021 23:45 EST

2012, Book chapter, Telemetry techniques: a user guide for fisheries research

John W. Beeman

Noah S. Adams, John W. Beeman, John H. Eiler, editor(s)

Released January 09, 2021 23:45 EST

2012, Book chapter, Telemetry techniques: a user guide for fisheries research

Scott D. Evans, John R. Stevenson

Noah S. Adams, John W. Beeman, John H. Eiler, editor(s)

Released January 09, 2021 23:45 EST

2012, Book chapter, Implementing the Dry Tortugas National Park Research Natural Area Science Plan-The 5-Year Report

Kristin M. Hart, Ikuko Fujisaki, Autumn R. Sartain

Dry Tortugas National Park (DRTO) harbors several key benthic habitats that are important for marine turtles. Threatened loggerhead turtles (<i>Caretta caretta</i>) forage in hard-bottom areas on spiny lobsters and crabs; endangered hawksbill turtles (<i>Eretmochelys imbricata</i>) forage on reefs and consume sponges; and endangered green turtles (<i>Chelonia mydas</i>) graze on seagrasses and marine algae. The sandy beaches of DRTO provide suitable nesting habitat for all three species.</p> <br/> <p>The majority of nesting activity at DRTO consists of nest construction on East and Loggerhead Keys by loggerhead and green turtles. In order to monitor the immigration and emigration of targeted species in the Research Natural Area (RNA), we characterized the populations of the three sea turtle species in DRTO and quantified the proportion of time individuals spent in the RNA as compared to other areas of the park. We examined turtle data with respect to the RNA and DRTO boundaries.</p> <br/> <p>We initiated our on-going turtle tagging and tracking project in 2008. To distribute capture effort within park boundaries, we captured nesting turtles on East and Loggerhead Keys, and captured turtles in the waters near Bush and Garden Keys, Northkey Harbor, and Pulaski Shoal. Our total area patrolled to catch turtles has expanded over time as determined by suitable turtle capture conditions, with more area being incorporated outside the RNA than inside the RNA. In addition to capture efforts, we recorded sightings of turtles as we patrolled the park by boat and marked the locations with a Global Positioning System (GPS) receiver. Sightings could include one or more turtles at a single location.</p> <br/> <p>Turtles were captured by intercepting reproductive females on nesting beaches and catching turtles in the water with rodeo (diving from boat to snorkel-capture turtles), hand-capture, and dip-netting methods. We individually marked each turtle with internal passive integrated transponder (PIT) tags and external flipper tags. We took standard length, width, and mass measurements and obtained blood and tissue samples for genetic, isotopic, and dietary analyses. We attached acoustic and/or satellite-telemetry tags to a subset of turtles.</p> <br/> <p>Seven acoustic receivers were placed by the U.S. Geological Survey (USGS) in the northeastern region of the park; all but one of these were placed outside the RNA. These locations were chosen based on spatial gaps in the network of receivers deployed by the Florida Fish and Wildlife Conservation Commission (FWC) and Mote Marine Laboratory (MML) (see Chapter 4, this volume). We received data from the FWC/MML receiver array, which included more than 80 receivers spread throughout the park in all management areas and outside the park to the southwest.</p> <br/> <p>Using satellite and acoustic telemetry techniques, we determined daily locations and movement patterns for tagged turtles, calculated home ranges and core-use areas, and statistically summarized the extent of overlap of these areas with that of the RNA. We used the kernel density estimation technique (KDE) (Worton 1989; White and Garrott 1990) to determine “hotspots” of turtle activity in the park. KDE is a method used to identify one or more areas of disproportionately heavy use (core-use areas) within a home-range boundary, with appropriate weighting of outlying observations. We also compared the number of turtle-days within and outside the RNA using only days the turtles spent inside the park (DRTO turtle-days). We combined these data sets to determine residence times inside the park and locations of core-use areas for all three species.</p> <br/> <p>It is essential to understand the locations, movements, estimated population size, preferred habitats, and status (for example nesting, foraging, number of juveniles and adults, etc.) of marine turtles within DRTO to effectively manage activities that affect these imperiled species. Our capture and tagging results summarized here can inform decision-makers by providing key information on these population characteristics. Our spatial habitat-use information provides details on locations and areas within and outside the park that turtles select, regardless of capture site.

Released January 09, 2021 23:45 EST

2012, Book chapter, Telemetry techniques: a user guide for fisheries research

Theodore Castro-Santos, Russell W. Perry

Noah S. Adams, John W. Beeman, John H. Eiler, editor(s)

Released January 09, 2021 23:45 EST

2012, Book chapter, Telemetry techniques: a user guide for fisheries research

Theodore Castro-Santos, Christopher M. Holbrook, Benjamin P. Sandford, Russell W. Perry

Noah S. Adams, John W. Beeman, John H. Eiler, editor(s)

Released January 09, 2021 23:45 EST

2012, Book chapter, Telemetry techniques: a user guide for fisheries research

Jill M. Hardiman, Christopher E. Walker, Timothy D. Counihan

Noah S. Adams, John W. Beeman, John H. Eiler, editor(s)

Released January 09, 2021 23:45 EST

2012, Book chapter, Telemetry techniques: a user guide for fisheries research

Eric Hockersmith, John W. Beeman, R Stevenson John

Noah S. Adams, John W. Beeman, John H. Eiler, editor(s)

Released January 09, 2021 23:45 EST

2012, Book chapter, Telemetry techniques: a user guide for fisheries research

John W. Beeman, Russell W. Perry

Noah S. Adams, John W. Beeman, John H. Eiler, editor(s)

Released January 09, 2021 23:45 EST

2012, Report

Jason G. Romine, Russell W. Perry, Theresa L. Liedtke

<p>The Sacramento River and its tributaries support populations of anadromous fish species including winter-run, spring-run, fall-run, and late fall–run Chinook salmon (Oncorhynchus tshawytscha); and steelhead (O. mykiss). Several of these species are listed as threatened or endangered under the California Endangered Species Act (CESA), federal Endangered Species Act (ESA), or both. These species spawn and rear in Sacramento River tributaries; adults use the mainstem Sacramento River for primarily upstream migration and juveniles use it for downstream migration. Juvenile Chinook salmon and steelhead migrate through the lower river during winter and spring. During their downstream migration, juvenile salmonids encounter alternative pathways, such as Sutter and Steamboat Sloughs, the Sacramento–San Joaquin Delta (Delta), Delta Cross Channel (DCC), and Georgiana Slough. Likewise, sturgeon juveniles migrate downstream in the Sacramento River basin to the Delta, utilizing the distributary channels to rear within and migrate through the system.</p> <br/> <p>Georgiana Slough is a natural channel that allows water and fish to move into the interior Delta. Previous studies have demonstrated that juvenile Chinook salmon experience greater mortality when migrating into Georgiana Slough than those juveniles that continue to migrate downstream in the Sacramento River (Perry 2010). Movement and/or diversion of these fish into the interior and south Delta increases the likelihood of losses through predation, entrainment into non-project Delta diversions, and mortality associated with the State Water Project (SWP) and Central Valley Project (CVP) pumping facilities in the south Delta (Perry 2010; NMFS 2009). Figure ES-1 shows the migration pathways in the lower Sacramento River and Delta for outmigrating anadromous salmonids, and the location of the DCC, and the SWP and CVP pumping facilities in the south Delta.</p> <br/> <p>Passage of juvenile salmonids from the Sacramento River into the interior Delta through the DCC can be reduced through seasonal closure of the radial gates (February through May); however, no similar protection is available to reduce the movement of juvenile salmonids from the Sacramento River into the interior Delta through Georgiana Slough. Flows into Georgiana Slough improve water quality and flushing in the interior Delta and free access encourages use by recreational boaters. Because of these benefits, alternatives to the installation of a physical barrier (i.e. radial gates), are being investigated.</p> <br/> <p>Under the ESA, the National Marine Fisheries Service (NMFS) issued the 2009 <i>Biological and Conference Opinion for the Long-Term Operations of the Central Valley Project and State Water Project</i> (BO) for Chinook salmon and other listed anadromous fish species (NMFS 2009). Reasonable and Prudent Alternative (RPA) Action IV.1.3 of the BO requires that the California Department of Water Resources (DWR) and the U.S. Bureau of Reclamation (Reclamation) to consider engineering solutions to reduce the difersion of juvenile salmonids from the Sacramento River into the interior and south Delta. DWR implemented the 2011 Georgiana Slough Non-Physical Barrier (GSNPB) Study to test the effectiveness of using a non-physical barrier, referred to as a behavioral Bio-Acoustic Fish Fence (BAFF), that combines three stimuli to deter juvenile Chinook salmon from entering Georgiana Slough: sounds, high-intensity modulated light (previous known as stroboscopic light), and a bubble curtain. This report presents the results of the experimental tests conducted in 2011.</p>

Released January 09, 2021 23:45 EST

2011, Book chapter, Coastal habitats of the Elwha River, Washington biological and physical patterns and processes prior to dam removal

Tracy L. Fuentes, Patrick B. Shafroth, Cynthia Pritekel, Matthew M. Beirne, Vanessa B. Beauchamp

Jeffrey J. Duda, Jonathan A. Warrick, Christopher S. Magirl, editor(s)

The Elwha River estuary supports one of the most diverse coastal wetland complexes yet described in the Salish Sea region, in terms of vegetation types and plant species richness. Using a combination of aerial imagery and vegetation plot sampling, we identified 6 primary vegetation types and 121 plant species in a 39.7 ha area. Most of the estuary is dominated by woody vegetation types, with mixed riparian forest being the most abundant (20 ha), followed by riparian shrub (6.3 ha) and willowalder forest (3.9 ha). The shrub-emergent marsh transition vegetation type was fourth most abundant (2.2 ha), followed by minor amounts of dunegrass (1.75 ha) and emergent marsh (0.2 ha). This chapter documents the abundance, distribution, and floristics of these six vegetation types, including plant species richness, life form, species origin (native or introduced), and species wetland indicator status. These data will serve as a baseline to which future changes can be compared, following the impending removal of Glines Canyon and Elwha Dams upstream on the Elwha River. Dam removals may alter many of the processes, materials, and biotic interactions that influence the estuary plant communities, including hydrology, salinity, sediment and wood transport, nutrients, and plant-microbe interactions.

Released January 09, 2021 23:45 EST

2011, Book chapter, Coastal habitats of the Elwha River, Washington- Biological and physical patterns and processes prior to dam removal

Patrick B. Shafroth, Tracy L. Fuentes, Cynthia Pritekel, Matthew M. Beirne, Vanessa B. Beauchamp

Jeffrey J. Duda, Jonathan A. Warrick, Christopher S. Magirl, editor(s)

The Elwha River estuary supports one of the most diverse coastal wetland complexes yet described in the Salish Sea region, in terms of vegetation types and plant species richness. Using a combination of aerial imagery and vegetation plot sampling, we identified 6 primary vegetation types and 121 plant species in a 39.7 ha area. Most of the estuary is dominated by woody vegetation types, with mixed riparian forest being the most abundant (20 ha), followed by riparian shrub (6.3 ha) and willowalder forest (3.9 ha). The shrub-emergent marsh transition vegetation type was fourth most abundant (2.2 ha), followed by minor amounts of dunegrass (1.75 ha) and emergent marsh (0.2 ha). This chapter documents the abundance, distribution, and floristics of these six vegetation types, including plant species richness, life form, species origin (native or introduced), and species wetland indicator status. These data will serve as a baseline to which future changes can be compared, following the impending removal of Glines Canyon and Elwha Dams upstream on the Elwha River. Dam removals may alter many of the processes, materials, and biotic interactions that influence the estuary plant communities, including hydrology, salinity, sediment and wood transport, nutrients, and plant-microbe interactions.

Released January 09, 2021 23:45 EST

2010, Conference Paper, Proceedings of the Joint Federal Interagency Conference 2010 : Hydrology and sedimentation for a changing future : existing and emerging issues

Amy E. Draut, Joshua B. Logan, Mark C. Mastin, Randall E. McCoy

To complement ongoing field studies of channel morphology, we evaluate decadal-scale evolution of the dammed lower Elwha River by using historical aerial photographs. Here, we revise an analysis published by Draut et al. (2008), which covered the interval 1939–2006, to include data collected after a major flood on December 3, 2007. That flood, which resulted from substantial rainfall on snow in the upper watershed, had instantaneous peak discharge of 1,016 m3/s (35,900 ft3/s), the second-highest recorded peak on the Elwha River since records began in 1898 and the largest since dam construction. A log-Pearson Type III flood-frequency analysis indicates that this flood would have a return interval of ~30 years (annual exceedence probability of ~0.03; C.S. Magirl, unpublished data). Observing channel change on the Elwha River from that event allows a more thorough characterization of the dammed channel’s response to flow over seasonal as well as annual and decadal time scales.

Released January 09, 2021 23:45 EST

2010, Report

Peter Ruggerio, Cheryl A. Brown, Paul D. Komar, Jonathan C. Allan, Deborah A. Reusser, Henry Lee II

<p>Earth’s changing climate is expected to have significant physical impacts along the coast and estuarine shorelands of Oregon, ranging from increased erosion and inundation of low lying areas, to wetland loss and increased estuarine salinity. The environmental changes associated with climate change include rising sea levels, increased occurrences of severe storms, rising air and water temperatures, and ocean acidification. The combination of these processes and their climate controls are important to beach and property erosion, flood probabilities, and estuarine water quality, with the expectation of significant changes projected for the 21st century.</p> <br/> <p>Coastal change and flood hazards along the Oregon coast are caused by a number of ocean processes, each of which has significant climate controls such that the severity and frequency of the hazards in the future can be expected to increase. There is near certainty that the rate of sea-level rise will increase in the future as a result of global warming, with the portential of greater than a 1.0 meter increase in sea level by 2100. Evaluating the consequences of intensigied and more frequent hazards is complicated by Oregon's tectonic setting, with there being significantly different rates of land uplift along the coast. Taken together, the variable rate of uplift plus the present-day rate of sea level rise, some stretches of the coast are submerging as the sea level rise is greater than the tectonic uplift, whereas other areas are emerging where the reverse is true. The prospects are that with accelerated rates of sea level rise, the entire coast will eventually be submerging and experience significantly greater erosion and flood impacts than at present day.</p> <br/> <p>Another long-term trend is increasing storm intensities and the heights of the waves they generate. In addition, the periodic occurrence of major El Niños in the future will compound the impacts of increasing sea levels and waves, resulting in severe episodes of coastal erosion and flooding, as experienced during the El Niño winters of 1982-83 and 1997-98. At present it is not known whether or not El Niño intensity and frequency will increase under a changing climate. With these multiple processes and their climate controls having important roles in causing erosion and flooding along the Oregon coast, it is challenging to collectively analyze them with the goal of providing meaningful assessments of future coastal hazards during the next several decades.</p> <br/> <p>Coastal infrastructure will come under increased risk to damage and inundation under a changing climate with impacted sectors including transportation and navigation, coastal engineering structures (seawalls, riprap, jetties etc.) and flood control and prevention structures, water supply and waste/storm water systems, and recreation, travel and hospitality.</p> <br/> <p>It is likely that regional coastal climate change will result in changes in the intensity and timing of coastal upwelling, shifts in temperatures and dissolved oxygen concentrations, and alteration of the carbonate chemistry (ocean acidification) of nearshore waters. The combination of these meteorological and nearshore ocean changes will exert stress on the communities of near-coastal and estuarine organisms. The range of community responses to the climate change stressors may include elevational shifts in the distribution of submerged aquatic vegetation, disruption of shell formation for calcifying organisms, alteration of the phenology of phytoplankton blooms, shoreward migration of tidal marshes, and increased colonization by non-indigenous aquatic species.</p> <br/> <p>Unfortunately, significant knowledge gaps remain, impairing our ability to accurately assess the impacts of climate change along our coast and estuarine shorelands. For example, the uncertainty of future global sea level rise is significant with credible projections ranging from less than 0.5 m to as much as 2.0 m by 2100. At present we do not conclusively understand the climate controls on increasing storm intensities and wave heights and therefore have a very limited ability to project future trends in coastal storm impacts. The magnitude and frequency of major El Niños has significant implications for the state of Oregon; however, at this time we are unable to assess whether or not these will increase in the future due to climate change. Further, the long-term time-series data necessary to definitively identify perturbations of estuarine communities that can be attributed to anthropogenic climate change are lacking and therefore our understanding of anticipated shifts remain largely speculative.</p>

Released January 09, 2021 23:45 EST

2009, Book chapter, Mirror Lake: interactions among air, land, and water

Gene E. Likens, James W. LaBaugh, Donald C. Buso, Darren Bade

Thomas C. Winter, Gene E. Likens, editor(s)

This chapter focuses on the variability and trends in chemical concentrations and fluxes at Mirror Lake during the period 1981–2000. It examines the water and chemical budgets of Mirror Lake to identify and understand better long-term trends in the chemical characteristics of the lake. It also identifies the causes of changes in nutrient concentrations and examines the contribution of hydrologic pathways to the contamination of Mirror Lake by road salt. The role of groundwater and precipitation on water and chemical budgets of the lake are also examined.

Released January 09, 2021 23:45 EST

1972, Technical Paper 60

G.L. Bullock

No abstract available at this time

Released January 09, 2021 19:45 EST

2012, Journal of Microbiological Methods (88) 103-109

Christina A. Kellogg, Yvette M. Piceno, Lauren M. Tom, Todd Z. DeSantis, David G. Zawada, Gary L. Andersen

Interest in coral microbial ecology has been increasing steadily over the last decade, yet standardized methods of sample collection still have not been defined. Two methods were compared for their ability to sample coral-associated microbial communities: tissue punches and foam swabs, the latter being less invasive and preferred by reef managers. Four colonies of star coral, Montastraea annularis, were sampled in the Dry Tortugas National Park (two healthy and two with white plague disease). The PhyloChip™ G3 microarray was used to assess microbial community structure of amplified 16S rRNA gene sequences. Samples clustered based on methodology rather than coral colony. Punch samples from healthy and diseased corals were distinct. All swab samples clustered closely together with the seawater control and did not group according to the health state of the corals. Although more microbial taxa were detected by the swab method, there is a much larger overlap between the water control and swab samples than punch samples, suggesting some of the additional diversity is due to contamination from water absorbed by the swab. While swabs are useful for noninvasive studies of the coral surface mucus layer, these results show that they are not optimal for studies of coral disease.

Released January 09, 2021 03:45 EST

2012, Book chapter, Telemetry techniques: a user guide for fisheries research

E Hockersmith Eric, John W. Beeman, John H. Eiler

Noah S. Adams, John W. Beeman, John Eiler, editor(s)

No abstract available.

Released January 08, 2021 12:15 EST

2021, Data Series 1132

Robert T. Kay

The U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources, designed and operates a network of monitoring stations on streams and springs throughout Missouri known as the Ambient Water-Quality Monitoring Network (AWQMN). During water year 2019 (October 1, 2018, through September 30, 2019), water-quality data were collected at 73 stations: 71 AWQMN and alternate AWQMN stations, and 2 U.S. Geological Survey National Water Quality Monitoring Program stations. Among the stations in this report, four stations have data presented from additional sampling performed in cooperation with the U.S. Army Corps of Engineers. Summaries of the concentrations of dissolved oxygen, specific conductance, water temperature, suspended solids, suspended sediment, Escherichia coli bacteria, fecal coliform bacteria, dissolved nitrate plus nitrite as nitrogen, total phosphorus, dissolved and total recoverable lead and zinc, and selected pesticides are presented. Most of the stations have been classified based on the physiographic province or primary land use in the watershed monitored by the station. Some stations have been classified based on the unique hydrologic characteristics of the waterbodies (springs, large rivers) they monitor. A summary of hydrologic conditions including peak streamflows, monthly mean streamflows, and 7-day low flows also are presented for representative streamflow-gaging stations in the State.

Released January 08, 2021 12:05 EST

1965, Water Data Report MD-DE-65-2

U.S. Geological Survey

No abstract available.

Released January 08, 2021 11:45 EST

1965, Water Data Report MD-DE-65-1

U.S. Geological Survey

No abstract available.

Released January 08, 2021 11:31 EST

2021, Techniques and Methods 4-F5

Bryant C. Jurgens, J.K. Böhlke, Karl Haase, Eurybiades Busenberg, Andrew G. Hunt, Jeffrey A. Hansen

DGMETA (Dissolved Gas Modeling and Environmental Tracer Analysis) is a Microsoft Excel-based computer program that is used for modeling air-water equilibrium conditions from measurements of dissolved gases and for computing concentrations of environmental tracers that rely on air-water equilibrium model results. DGMETA can solve for the temperature, salinity, excess air, fractionation of gases, or pressure/elevation of water when it is equilibrated with the atmosphere. Models are calibrated inversely using one or more measurements of dissolved gases such as helium, neon, argon, krypton, xenon, and nitrogen. Excess nitrogen gas, originating from denitrification or other sources, also can be included as a fitted parameter or as a separate calculation from the dissolved gas modeling results. DGMETA uses the air-water equilibrium models to separate measured concentrations of gases and isotopes of gases into components that are used for tracing water in the environment. DGMETA calculates atmospheric dry-air mole fractions (mixing ratios) for transient atmospheric gas tracers such as chlorofluorocarbons, sulfur hexafluoride, and bromotrifluoromethane (Halon-1301); and concentrations of tritiogenic helium-3 and radiogenic helium-4, which accumulate from the decay of tritium in water and the decay of uranium and thorium in rocks, respectively. 

Sample data can be graphed to identify applicable models of excess air, samples that contain excess nitrogen gas, or samples that have partially degassed, for example. Monte Carlo analysis of errors associated with dissolved gas equilibrium model results can be carried through computations of environmental tracer concentrations to provide robust estimates of error. In addition, graphical routines for separating helium sources using helium isotopes are included to refine estimates of tritiogenic helium-3 when terrigenic helium from mantle or crustal sources is present in samples. Environmental tracer concentrations and their errors computed from DGMETA can be used with other programs, such as TracerLPM (Jurgens and others, 2012), to determine groundwater ages and biogeochemical reaction rates. DGMETA also produces output files in a format that meets the U.S. Geological Survey open data requirements for documentation of model inputs and outputs. 

DGMETA is a versatile and adaptable program that allows users to add solubility data for new gases, modify the existing set of gas solubility data, modify the default set of gases used for modeling, choose calculations based on real (non-ideal) gas behavior, and select various concentration units for data entry and results to match laboratory reports and study objectives. DGMETA comes with a set of gases widely used in hydrology and oceanography and many gases include multiple solubilities from previous work. Seventeen dissolved gases are included in the default version of the program: noble gases (helium, neon, argon, krypton, and xenon), reactive gases (nitrogen, oxygen, methane, carbon dioxide, carbon monoxide, hydrogen, and nitrous oxide), and environmental tracers (chlorofluorocarbon-11, chlorofluorocarbon-12, chlorofluorocarbon-113, sulfur hexafluoride, and Halon-1301).

Released January 08, 2021 10:44 EST

2021, Toxicon (192) 1-14

Meredith D. A. Howard, Raphael M. Kudela, Kendra Hayashi, Avery O. Tatters, David A. Caron, Susanna Theroux, Stuart Oehrle, Miranda Roethler, Ariel Donovan, Keith Loftin, Zachary Laughrey

Released January 08, 2021 07:26 EST

2021, Nature Communications (12)

Kimberly Mayfield, Anton Eisenhauer, Danielle P. Santiago Ramos, John A. Higgins, Tristan Horner, Maureen Auro, Tomas Magna, Nils Moosdorf, Matthew Charette, Meagan Gonneea Eagle, Carolyn Brady, Nemanja Komar, Bernard Peucker-Ehrenbrink, Adina Paytan

Released January 08, 2021 07:04 EST

2021, Oecologia

Michala Lee Phillips, Daniel E. Winkler, Robin H. Reibold, Brooke Bossert Osborne, Sasha Reed

Released January 07, 2021 17:25 EST

2021, Scientific Investigations Report 2020-5131

Jessica D. Garrett

In support of nutrient reduction efforts, total phosphorus loads and yields were computed for the Turkey River at Garber, Iowa (U.S. Geological Survey station 05412500), for January 1, 2018, to April 30, 2020, based on continuously monitored turbidity sensor data. Sample data were used to create a total phosphorus turbidity-surrogate model. Streamflow-based total phosphorus models were used during periods of missing sensor data to obtain a more complete annual total phosphorus load. This report presents methods needed to accurately compute site-specific loads and track annual progress toward nutrient reduction goals within the State.

Annual total phosphorus loads for the Turkey River at Garber, Iowa, were 1,740 and 1,490 U.S. short tons for 2018 and 2019, respectively, with annual yields ranging from 3.01 to 3.53 pounds per acre per year, compared to a mean statewide yield of 0.73 pound per acre per year needed to achieve the total phosphorus-reduction goal.

Released January 07, 2021 15:35 EST

2021, Scientific Investigations Report 2020-5119

Kristen J. Valseth, Daniel G. Driscoll

The U.S. Geological Survey (USGS), in cooperation with the Rosebud Sioux Tribe, completed a study to characterize water-level fluctuations in observation wells to examine driving factors that affect water levels in and near the Rosebud Indian Reservation, which comprises all of Todd County. The study investigates concerns regarding potential effects of groundwater withdrawals and climate conditions on groundwater levels within an area that includes Todd County and a surrounding area that extends 10 miles north, east, and west of the county border. Characterization of water-level fluctuations in observation wells and relative driving factors was accomplished by statistical trend analysis.

Two statistical methods were used for analysis of temporal trends for climatic and hydrologic data. To determine which trend analysis to use, applicable datasets were tested for statistically significant short-term persistence (STP). In the absence of significant STP, existence of statistical trends was determined using the standard Mann-Kendall test for probability values less than or equal to 0.10 (90-percent confidence level); however, a modified Mann-Kendall test was used for datasets where statistically significant STP was detected. Trend magnitudes were computed using the Sen’s slope estimator.

Monthly data from the Parameter-elevation Regressions on Independent Slopes Model (PRISM) were aggregated to obtain annual and seasonal datasets for total precipitation, minimum air temperature (T_min), and maximum air temperature (T_max) for the study area and a surrounding buffer area. Trend tests for total precipitation, T_min, and T_max were completed for annual and seasonal time series for water years 1956–2017, which is about 2 years before the earliest available water-level measurements. A 2-year offset was arbitrarily selected because scrutiny of water-level and precipitation data indicated that responses of groundwater levels for many of the observation wells lagged major changes in precipitation patterns by about 2 years. Statistically significant upward trends were detected for annual precipitation and annual T_min for almost all of the study area and the surrounding buffer area. Statistically significant downward trends in T_max were detected for a very small part of the study area; however, the sparse spatial coverage reduces confidence that these are true trends. Spatial distributions of statistically significant trends in seasonal climate data were generally similar to the annual trends, but with substantial differences in the spatial density of the trends.

Groundwater trends for 58 observation wells were analyzed for three separate water-level parameters (minimum, median, and maximum) because wells are measured sporadically and data are biased towards more frequent measurements during periods of heaviest irrigation demand. Trends in the time series of annual precipitation (from PRISM) starting 2 years earlier than for the associated water-level trend also were analyzed for the location of each individual observation well. Sen’s slope and Mann-Kendall probability values (p-values) were computed for the three water-level parameters and for the annual precipitation time series. Graphs showing results of trend analyses for each observation well also showed changes over time in the sum of licensed groundwater withdrawals within six specified radii (0.5, 1, 2, 3, 4, and 5 miles) of each well as a qualitative indicator of proximal groundwater demand.

Of all 58 observation wells considered, 28 wells had significant upward trends for at least one of the three water-level parameters, 11 wells had significant downward trends for at least one water-level parameter, and 19 wells did not have any significant trends. Significant upward trends in annual precipitation were detected for 48 of the 58 wells.

Results of trend analyses likely show the effects of groundwater withdrawals on water levels in the Ogallala aquifer in areas of substantial demand. Precipitation trends are significantly upward for 43 of the 48 wells completed in the Ogallala aquifer that were analyzed. Of the 48 Ogallala aquifer wells, 24 had significant upward trends for at least one water-level parameter (17 with all 3); however, 10 wells had statistically significant downward trends for at least one water-level parameter (8 with all 3 parameters). All but one of the wells with significant downward trends are located in the south-central part of the study area where licensed irrigation withdrawals are concentrated.

Released January 07, 2021 15:05 EST

2021, Scientific Investigations Report 2020-5136

Gregory E. Granato, Alana B. Spaetzel, Laura Medalie

This report documents statistics for simulating structural stormwater runoff best management practices (BMPs) with the Stochastic Empirical Loading and Dilution Model (SELDM). The U.S. Geological Survey developed SELDM and the statistics documented in this report in cooperation with the Federal Highway Administration to indicate the risk for stormwater flows, concentrations, and loads to exceed user-selected water-quality goals and the potential effectiveness of mitigation measures to reduce such risks. In SELDM, three treatment variables—hydrograph extension, volume reduction, and water-quality treatment—are simulated by using the trapezoidal distribution and the rank correlation with the associated runoff variables. This report describes methods for calculating the trapezoidal distribution statistics and rank correlation coefficients for these treatment variables and methods for estimating the minimum irreducible concentration (MIC), which is the lowest expected effluent concentration from a BMP site or a category of BMPs. These statistics are different from the statistics commonly used to characterize or compare BMPs; they are designed to provide a stochastic transfer function to approximate the quantity, duration, and quality of BMP effluent given the associated inflow values for a population of storm events.

Analyses for this study were done with data extracted from a modified copy of the December 2019 version of the International Stormwater Best Management Practices Database. Statistics for volume reduction, hydrograph extension, and water-quality treatment were developed with selected data. The medians of the best-fit statistics for selected constituents were used to construct generalized cumulative distribution functions for the three treatment variables. For volume reduction and hydrograph extension, selection of a Spearman’s rank correlation coefficient (rho) value that is the average of the median and maximum values for the BMP category may help generate realistic simulation results in SELDM. The median rho value may be selected to help generate realistic simulation results for water-quality treatment variables.

Water-quality treatment statistics, including trapezoidal ratios and MIC values, were developed for 51 runoff-quality constituents commonly measured in highway and urban runoff studies. Statistics were calculated for water-quality properties, sediment and solids, nutrients, major and trace inorganic elements, organic compounds, and biologic constituents.

Analysis of MIC values provides information to guide professional judgement for selecting values for simulating water quality at sites of interest. The MIC is a lower bound for BMP discharge concentrations and will therefore replace simulated BMP discharge concentrations below the selected value. A new method for estimating MIC values, the lognormal variate of inflow concentrations, was developed in this report and these statistics were calculated for individual constituents and constituent categories. Inflow quality is correlated to MIC values for some constituents, but regional soil concentrations were not strongly correlated to MIC values.

Released January 07, 2021 13:30 EST

2021, Open-File Report 2020-1132

Leslie Hsu

The U.S. Geological Survey (USGS) Community for Data Integration (CDI) Workshop was held during June 3–7, 2019, at Center Green in Boulder, Colo. The theme of the workshop was “From Big Data to Smart Data” with the purpose of bringing together the community to discuss current topics, shared challenges, and steps forward to advance twenty-first century science at the USGS. The workshop agenda was driven by the needs of the CDI with topics highlighting current resources and technologies that could help attendees in their daily work. Workshop-session categories included enabling integrated science, computing in the cloud, advancing data management, releasing and preserving science outputs, and improving usability and communication. These proceedings provide documentation of the plenary talks, topical-session content and notes, posters, live demonstrations, and attendee comments from the 2019 CDI Workshop.

Released January 07, 2021 13:10 EST

2021, Fact Sheet 2021-3002

U.S. Geological Survey

Landsat Collections ensure that all Landsat Level-1 data are consistently calibrated and processed and retain traceability of data quality provenance. Landsat Collection 2 introduces improvements that harness recent advancements in data processing, algorithm development, data access, and distribution capabilities. Collection 2 includes Landsat Level-1 data for all sensors since 1972 and global Level-2 surface reflectance and surface temperature scene-based products for data acquired since 1982 starting with the Landsat Thematic Mapper sensor era.

Released January 07, 2021 11:29 EST

2021, Scientific Investigations Report 2020-5115

Chui Ling Cheng, Scot K. Izuka, Joseph Kennedy, Abby G. Frazier, Thomas W. Giambelluca

In cooperation with the State of Hawai‘i Commission on Water Resource Management and in collaboration with the University of Hawaiʻi Water Resources Research Center, the U.S. Geological Survey developed a water-resource monitoring program—a rainfall, surface-water, and groundwater data-collection program—that is required to meet State needs for water-resource assessment, management, and protection in Hawai‘i. Current and foreseeable issues related to water-resource management and climate-change effects guided the evaluation of data-collection sites within the monitoring program. Data-collection sites currently (2018) being operated in Hawai‘i were evaluated, and additional data-collection sites were selected on the basis of their usefulness for characterizing anthropogenic effects on water resources or representing natural conditions. Data-collection strategies consist of a combination of continuous long-term monitoring to evaluate trends and climate-change effects and occasional and periodic intensive monitoring to enhance spatial understanding of hydrologic conditions and to address current issues in priority areas—areas that currently have water-availability issues or are expected to have the greatest socioeconomic or ecological effects because of climate change.

Priority areas for rainfall monitoring consist of urban and agricultural lands, areas with high rainfall and high-rainfall gradient, and areas within the trade-wind inversion band. Surface-water priority areas consist of streams with major surface-water diversions, with established interim instream-flow standards, in a surface-water management area, that support water leases, and with uncertainties in hydrogeologic characteristics. Priority areas for groundwater monitoring consist of areas with high withdrawal, declining water levels, reduced recharge, limited alternative sources, and uncertainties in hydrogeologic characteristics.

Data-quality objectives for the rainfall, surface-water, and groundwater monitoring programs that describe anticipated uses of the data were established with the goal of producing useful, reliable, and accurate water-resource information of sufficient precision to support decision making. The data-quality objectives also consider quality-assurance and quality-control programs that ensure defensible data. Establishment of common data-quality objectives not only assures comparability of data collected by multiple agencies but also allows data from academic, private, and public organizations to be useful for meeting State monitoring needs, provided the data meet appropriate data-quality objectives and data-accessibility requirements.

Released January 07, 2021 10:14 EST

2021, Professional Paper 1867-F

Shaul Hurwitz, Sara E. Peek, Martha A. Scholl, Deborah Bergfeld, William C. Evans, James P. Kauahikaua, Stephen B. Gingerich, Paul A. Hsieh, R. Lopaka Lee, Edward F. Younger, Steven E. Ingebritsen

Matthew R. Patrick, Tim R. Orr, Don Swanson, Bruce F. Houghton, editor(s)

Kīlauea Volcano, on the Island of Hawaiʻi, is surrounded and permeated by active groundwater systems that interact dynamically with the volcanic system. A generalized conceptual model of Hawaiian hydrogeology includes high-level dike-impounded groundwater, very permeable perched and basal aquifers, and a transition (mixing) zone between freshwater and saltwater. Most high-level groundwater is associated with the low-permeability intrusive complexes that underlie volcanic rift zones and calderas and also act to compartmentalize the groundwater system. Hydrogeologic studies of Kīlauea in recent decades, accompanied by deep research drilling, have shown that high-level groundwater is more widespread than once understood, that permeability decreases dramatically at depth, particularly in rift zones, and that freshwater can occur at depths of as much as several kilometers below the local water table. Copious groundwater recharge causes near-surface conductive heat flow to be near zero over much of Kīlauea. Approximately 95 percent of groundwater discharge occurs offshore, accompanied by approximately 99 percent of the approximately 6,000 megawatts of heat supplied by magmatic intrusion. Here, we summarize current understanding of the groundwater system of Kīlauea Volcano and describe transient changes during the decade or more preceding the 2018 eruption sequence. The changes in groundwater chemistry and thermal structure beneath Kīlauea summit hold implications for volcanic-volatile transport and the potential for explosive volcanism. Between 2008 and 2018, the magma conduit beneath the lava lake likely created an adjacent zone of very hot rock that significantly delayed liquid groundwater inflow to the draining magma conduit. Sulfate concentrations in groundwater beneath Kīlauea summit, sampled at the National Science Foundation-funded drill hole 1.5 kilometers south-southwest of the lava lake, declined substantially between 2010 and present. This decline likely reflects, at least in part, the decreased effectiveness of volatile condensation and solution into groundwater (scrubbing). The vent opening in 2008 presumably focused volatile flux into the vicinity of the vent, and progressive drying of the surroundings further restricted interaction with the groundwater system. The decrease in sulfate concentrations in the drill hole between 2010 and 2018 likely reflects decreased effectiveness of scrubbing.

Released January 07, 2021 10:06 EST

2021, Professional Paper 1867

Matthew R. Patrick, Tim R. Orr, Don Swanson, Bruce F. Houghton, editor(s)

The 2008–2018 lava lake at the summit of Kīlauea marked the longest sustained period of lava lake activity at the summit in decades and provided a new opportunity for observing and understanding lava lake behavior. The individual chapters of this Professional Paper volume cover the basic chronology of the eruption, rich historical background, observations and measurements of lake activity, hydrological setting, as well as geophysical and other monitoring data that tracked the activity.  

The primary focus of this Professional Paper is the 2008–2018 lava lake activity, ending with the draining of the lake in May 2018. The 2018 summit collapse events that followed the lake draining, and which dramatically altered the topography of the summit region, are published elsewhere.  

As this volume was published online in January 2021, a new lava lake had just formed in Halemaʻumaʻu.  This new activity is further testament to the dynamic nature of Halemaʻumaʻu and the proclivity for lava lake activity at the summit of Kīlauea.

Released January 07, 2021 10:06 EST

2021, Professional Paper 1867-B

Ben Gaddis, James P. Kauahikaua

Matthew R. Patrick, Tim R. Orr, Don Swanson, Bruce F. Houghton, editor(s)

The 2018 eruption of Kīlauea Volcano marked the end of the first sustained period of volcanic activity at Halemaʻumaʻu Crater in 94 years. The views of the lava lake (informally named “Overlook,” nestled within Halemaʻumaʻu) lasted for a decade and seemed timeless. But as we were recently reminded, the summit of Kīlauea is part of a dynamic system that has provided countless new views to observers over the centuries.

This visual essay features a few of the many scenes recorded by early observers at the volcano, from the first visits by westerners in 1823 through the explosive eruption of 1924. The early images left by casual visitors, artists, and photographers raise many questions: What is shown? Where is this? Who captured the scene and when? How accurate is the portrayal? Where possible, we attempt to answer these questions and provide interpretations of the images featured.

In 1912, the nature of observations at Kīlauea changed when Thomas A. Jaggar, Jr., and others occupied the Hawaiian Volcano Observatory on a full-time basis. They began a visual and written record of what they saw, heard, and experienced that has continued to this day. We describe some of the early work of these scientists and photographers, and showcase the results.

Released January 07, 2021 09:56 EST

2021, Professional Paper 1867-A

Matthew R. Patrick, Tim R. Orr, Don Swanson, Bruce F. Houghton, Kelly M. Wooten, Liliana Desmither, Carolyn Parcheta, David Fee

Matthew R. Patrick, Tim R. Orr, Don Swanson, Bruce F. Houghton, editor(s)

The first eruption at Kīlauea’s summit in 25 years began on March 19, 2008, and persisted for 10 years. The onset of the eruption marked the first explosive activity at the summit since 1924, forming the new “Overlook crater” (as the 2008 summit eruption crater has been informally named) within the existing crater of Halemaʻumaʻu. The first year consisted of sporadic lava activity deep within the Overlook crater. Occasional small explosions deposited spatter and small wall-rock lithic pieces around the Halemaʻumaʻu rim. After a month-long pause at the end of 2008, deep sporadic lava lake activity returned in 2009. Continuous lava lake activity began in February 2010. The lake rose significantly in late 2010 and early 2011, before subsequently draining briefly in March 2011. This disruption of the summit eruption was triggered by eruptive activity on the East Rift Zone. Rising lake levels through 2012 established a more stable, larger lake in 2013, with continued enlargement over the subsequent 5 years. Lava reached the Overlook crater rim and overflowed on the Halemaʻumaʻu floor in brief episodes in 2015, 2016, and 2018, but the lake level was more commonly 20–60 meters below the rim during 2014–18. The lake was approximately 280×200 meters (~42,000 square meters) by early 2018 and formed one of the two largest lava lakes on Earth.

A new eruption began in the lower East Rift Zone on May 3, 2018, causing magma to drain from the summit reservoir complex. The lava in Halemaʻumaʻu had drained below the crater floor by May 10, followed by collapse of the Overlook and Halemaʻumaʻu craters. The collapse region expanded as much of the broader summit caldera floor subsided incrementally during June and July. By early August 2018, the collapse sequence had ended, and the summit was quiet. The historical changes in May–August 2018 brought a dramatic end to the decade of sustained activity at Kīlauea’s summit.

The unique accessibility of the 2008–18 lava lake provided new observations of lava lake behavior and open-vent basaltic outgassing. Data indicated that explosions were triggered by rockfalls from the crater walls, that the lake consisted of a low-density foamy lava, that cycles of gas pistoning were rooted at shallow depths in the lake, and that lake level fluctuations were closely tied to the pressure of the summit magma reservoir. Lava chemistry added further support for an efficient hydraulic connection between the summit and East Rift Zone. Notwithstanding the benefits to scientific understanding, the eruption presented a persistent hazard of volcanic air pollution (vog) that commonly extended far from Kīlauea’s summit.

Released January 07, 2021 09:20 EST

2021, Mineralium Deposita

Leonid Neymark, Christopher S. Holm-Denoma, Anatoly Larin, Richard J. Moscati, Yulia Plotkina

U-Pb dating of cassiterite and zircon from the Yazov granite (Transbaikalia region, Eastern Siberia, Russia) and cassiterite from spatially associated tin mineralization in the Tuyukan ore district in the Tonod uplift was conducted using in situ laser ablation inductively coupled plasma mass spectrometry. These analyses allow comparison of isotopic systematics for both minerals, especially related to transport in granitic magma. These data are also useful for understanding possible genetic links between the granite and the tin mineralization. Most of the U-Pb zircon analyses define a ²⁰⁶Pb/²³⁸U age of 719 ± 15 Ma for the granite; in addition, several zircon cores define an inheritance age of 1839 ± 21 Ma. U-Pb data for 10 nearly concordant analyses of disseminated cassiterite from the same samples yield a ²⁰⁶Pb/²³⁸U age of 1838 ± 34 Ma. This is the first documented evidence of cassiterite inheritance in granitic magma. These data indicate the robust character of U-Pb isotope systematics in cassiterite, comparable to that in zircon. The presence of numerous inclusions of cassiterite in zircon from the Yazov granite (revealed by nanotomography) supports the interpretation of inherited cassiterite included during Neoproterozoic zircon crystallization. The data indicate that high tin concentrations in the Yazov granite are due to the incorporation of older cassiterite crystals from country rock, not coeval cassiterite crystallization. Cassiterite samples from two ore occurrences spatially associated with the Yazov granite yield Pb-Pb isochron ages of 1.86–1.82 Ga, indicating that tin mineralization occurred in the Paleoproterozoic, nearly 1 Ga before emplacement of the Yazov granite. Tin mineralization of the ore region is probably related to ~ 1.85 Ga Chuya-Kodar tin-bearing granitic rocks that host tin deposits. These results have broad implications for understanding how critical elements, such as tin, may become enriched in rare-metal granites and how they are related to regional to global geodynamic processes.

Released January 07, 2021 08:45 EST

1997, Water Data Report MD-DE-96-2

M.J. Smigaj, R.W. Saffer, R.J. Starsoneck, J.L. Tegeler

No abstract available. 

Released January 07, 2021 08:40 EST

1997, Water Data Report MD-DE-96-1

R.W. James, B.M. Helinsky, R.H. Simmons, A.J. Tallman

No abstract available.

Released January 07, 2021 08:40 EST

1995, Water Data Report MD-DE-95-2

M.J. Smigaj, R.W. Saffer

No abstract available.

Released January 07, 2021 08:35 EST

1995, Water Data Report MD-DE-95-1

R.W. James, R.H. Simmons, B.M. Helinsky

No abstract available,

Released January 07, 2021 08:30 EST

1994, Water Data Report MD-DE-94-2

M.J. Smigaj, R.W. Saffer, J.L. Tegeler

No abstract available.

Released January 07, 2021 08:25 EST

1994, Water Data Report MD-DE-94-1

R.W. James, R.H. Simmons, B.F. Strain

No abstract available.

Released January 07, 2021 08:20 EST

1993, Water Data Report MD-DE-93-2

M.J. Smigaj, R.W. Saffer, J.L. Tegeler

No abstract available.

Released January 07, 2021 08:15 EST

1993, Water Data Report MD-DE-93-1

R.W. James, R.H. Simmons, B.F. Strain

No abstract available.

Released January 07, 2021 08:15 EST

1991, Water Data Report MD-DE-91-1

R.W. James, J.F. Hornlein, R.H. Simmons, B.F. Strain

No abstract available.

Released January 07, 2021 08:10 EST

1992, Water Data Report MD-DE-92-2

R.W. James, M.J. Smigaj

No abstract available.

Released January 07, 2021 08:05 EST

1992, Water Data Report MD-DE-92-1

R.W. James, R.H. Simmons, B.F. Strain, J.F. Hornlein

No abstract available.

Released January 07, 2021 08:04 EST

2021, Frontiers in Marine Science (7)

William Skirving, Andrew Pomeroy, Robert T. McCall, John Marra, Curt Storlazzi

No abstract available.

Released January 07, 2021 08:00 EST

1991, Water Data Report MD-DE-91-2

R.W. James, M.J. Smigaj

No abstract available.

Released January 07, 2021 07:44 EST

2021, Microbiology Resource Announcements (10)

Andrew B. Reeves, Mary Lea Killian, Michael E Tanner, Benjamin Joel Lagasse, Andrew M. Ramey, David E. Stallknecht, Rebecca L. Poulson

Released January 07, 2021 07:11 EST

2021, Landslides

Sujana Timilsina, Jeffrey D. Niemann, Sara L. Rathburn, Francis K. Rengers, Peter A. Nelson

Released January 07, 2021 07:04 EST

2021, Mineralium Deposita

Saulo B de Oliveira, Craig A. Johnson, Caetano Juliani, Lena VS Monteiro, David L Leach, Marianna G.N. Caran

The Shalipayco Zn–Pb deposit, in central Peru, is composed of several stratabound orebodies, the largest of which are the Resurgidora and Intermedios, contained in carbonate rocks of the Upper Triassic Chambará Formation, Pucará group. Petrography suggests that a single ore-forming episode formed sphalerite and galena within vugs, open spaces, and fractures. Three-dimensional (3D) geological modeling has allowed division of the Chambará Formation into four members (Chambará I, II, III, and IV) that better define lithological controls on sulfide formation. Diagenetic replacement of evaporite minerals with the organic matter (OM) presence likely generated secondary porosity and H₂S accumulation by bacterial sulfate reduction (BSR), providing ground preparation for the later Zn–Pb mineralizing event. The least-altered host rocks have C–O isotope compositions of 1.8 ± 0.1‰ (VPDB) and 29.9 ± 2.1‰ (VSMOW), respectively, within the Triassic marine carbonate ranges. Early dolomite contains lighter C–O composition (1.1 ± 0.9 and 23.8 ± 2.9‰, respectively) consistent with OM decomposition during burial diagenesis. Post-mineralization calcite has still lighter C–O composition (− 5.1 and 13.3‰, respectively), suggesting meteoric water that had migrated through organic-rich strata. The strontium isotopes of Mitu group basalts (0.709654–0.719669) indicate it as a possible, but not the unique source of strontium and probably of other metals. Highly negative sulfide sulfur isotope values (− 23.3 to − 6.2‰ (VCDT)) indicate a major component of the ore sulfur derived ultimately from BSR. However, multiple lines of evidence suggest that preexisting H₂S underwent thermochemical redox cycling prior to ore formation. The influx of hot metalliferous brines to dolomitized zones containing trapped H₂S is the preferred model for ore deposition at Shalipayco.

Released January 06, 2021 15:10 EST

1989, Water Data Report MD-DE-89-2

R.W. James, R.H. Simmons, B.F. Strain, M.J. Smigaj

No abstract available.

Released January 06, 2021 15:10 EST

1983, Water Data Report MD-DE-82-1

R.W. James, R.H. Simmons, B.F. Strain

No abstract available.

Released January 06, 2021 15:05 EST

1990, Water Data Report MD-DE-90-2

R.W. James, J.F. Hornlein, R.H. Simmons, M.J. Smigaj

No abstract available.

Released January 06, 2021 14:55 EST

1990, Water Data Report MD-DE-90-1

R.W. James, J.F. Hornlein, B.F. Strain, M.J. Smigaj

No abstract available.

Released January 06, 2021 14:40 EST

1989, Water Data Report MD-DE-89-1

R.W. James, R.H. Simmons, B.F. Strain, M.J. Smigaj

No abstract available.

Released January 06, 2021 14:35 EST

1988, Water Data Report MD-DE-88-1

R.W. James, R.H. Simmons, B.F. Strain, M.J. Smigaj

No abstract available.

Released January 06, 2021 14:35 EST

1987, Water Data Report MD-DE-87-1

R.W. James, R.J. Simmons, B.F. Strain

No abstract available.

Released January 06, 2021 14:30 EST

1986, Water Data Report MD-DE-86-1

R.W. James, R.H. Simmons, B.F. Strain

No abstract available. 

Released January 06, 2021 14:25 EST

1986, Water Data Report MD-DE-85-1

R.W. James, R.H. Simmons, B.F. Strain

No abstract available.

Released January 05, 2021 12:20 EST

2020, Open-File Report 2020-1118

Zachery W. Fehr, Kimberly K. Yates

Bathymetric geoprocessing analyses of the Florida Reef Tract have provided insights into trends of seafloor accretion and seafloor erosion over time and following major storm events. However, bathymetric surveys sometimes capture manmade structures and vegetation, which do not represent the desired bare-earth data. Therefore, ground truthing is essential to maintain the most accurate bathymetric data possible. Field procedures were developed in the Florida Reef Tract in order to quickly and accurately collect consistent imagery and habitat data across variable sites. Areas of significant elevation change were determined through elevation change analyses; these areas were targeted for ground truthing in order to check the reliability of the surveys. This report outlines the standard operating procedures for underwater photographic imagery and habitat data collection, as well as procedures for the storage of these photographs and associated metadata. These standard operating procedures ensure the reproducibility of photographic operations and habitat data collection in future field excursions, enable longitudinal visual comparisons alongside seafloor elevation change analyses, and also have the potential to be applied to similar studies in different coastal environments.

Released January 05, 2021 08:16 EST

2021, Bulletin of the Seismological Society of America

Kevin R. Milner, Bruce E. Shaw, Christine A. Goulet, Keith B. Richards-Dinger, Scott Callaghan, Thomas H. Jordan, James H. Dieterich, Edward H. Field

Released January 05, 2021 08:07 EST

2021, Water Resources Research

N LeRoux, B. Kurylyk, Martin A. Briggs, D. Irvine, J Tamborski, V. F. Bense

Released January 02, 2021 06:59 EST

2021, Molecular Ecology

Richard G.J. Hodel, Robert Massatti, Sasha G.D. Bishop, L. Lacey Knowles

Co‐distributed species may exhibit similar phylogeographic patterns due to shared environmental factors or discordant patterns attributed to the influence of species‐specific traits. Although either concordant or discordant patterns could occur due to chance, stark differences in key traits (e.g., dispersal ability) may readily explain differences between species. Multiple species’ attributes may affect genetic patterns, and it is difficult to isolate the contribution of each. Here we compare the relative importance of two attributes, range size and niche breadth, in shaping the spatial structure of genetic variation in four sedge species (genus Carex) from the Rocky Mountains. Within two pairs of co‐distributed species, one species exhibits narrow niche breadth, while the other species has broad niche breadth. Furthermore, one pair of co‐distributed species has a large geographical distribution, while the other has a small distribution. The four species represent a natural experiment to tease apart how these attributes (i.e., range size and niche breadth) affect phylogeographic patterns. Investigations of genetic variation and structure revealed that range size, but not niche breadth, is related to spatial genetic covariation across species of montane sedges. Our study highlights how isolating key attributes across multiple species can inform their impact on processes driving intraspecific differentiation.

Released January 01, 2021 23:45 EST

2012, Book chapter, Telemetry techniques: a user guide for fisheries research

Theresa L. Liedtke, Wargo Rub Michelle

Noah S. Adams, John W. Beeman, Wargo Rub Michelle, editor(s)

Released January 01, 2021 07:57 EST

2021, Science (371) 34-36

Gerardo Herrera, Pablo Ezquerro, Roberto Tomás, Marta Béjar-Pizarro, Juan López-Vinielles, Mauro Rossi, Rosa M. Mateos, Dora Carreón-Freyre, John Lambert, Pietro Teatini, Enrique Cabral-Cano, Gilles Erkens, Devin Galloway, Wei-Chia Hung, Najeebullah Kakar, Michelle Sneed, Luigi Tosi, Hanmei Wang, Shujun Ye

Subsidence, the lowering of Earth's land surface, is a potentially destructive hazard that can be caused by a wide range of natural or anthropogenic triggers but mainly results from solid or fluid mobilization underground. Subsidence due to groundwater depletion (1) is a slow and gradual process that develops on large time scales (months to years), producing progressive loss of land elevation (centimeters to decimeters per year) typically over very large areas (tens to thousands of square kilometers) and variably affects urban and agricultural areas worldwide. Subsidence permanently reduces aquifer-system storage capacity, causes earth fissures, damages buildings and civil infrastructure, and increases flood susceptibility and risk. During the next decades, global population and economic growth will continue to increase groundwater demand and accompanying groundwater depletion (2) and, when exacerbated by droughts (3), will probably increase land subsidence occurrence and related damages or impacts. To raise awareness and inform decision-making, we evaluate potential global subsidence due to groundwater depletion, a key first step toward formulating effective land-subsidence policies that are lacking in most countries worldwide.

Released December 31, 2020 19:45 EST

2011, Earth (56) 24-26

M.W. Hamburger, W.D. Mooney

[No abstract available]

Released December 31, 2020 11:15 EST

2020, Fact Sheet 2020-3070

Jena M. Huntington, Derek C. Entz, Carl E. Thodal

A pesticide is a substance, or mixture of substances, used to kill or control insects, weeds, plant diseases, and other pest organisms. Commercial pesticide applicators, farmers, and homeowners apply about 1.1 billion pounds of pesticides annually to agricultural land, non-crop land, and urban areas throughout the United States. Although intended for beneficial uses, there are also risks associated with pesticide applications, including contamination of groundwater and surface-water resources, which can adversely affect aquatic life and water supplies. Pesticides can contaminate groundwater and surface water directly through point sources (spills, disposal sites, or pesticide drift during an application). The main avenue of contamination, however, is indirect by non-point sources, which include agricultural and urban runoff, erosion, leaching from application sites, and precipitation that has become contaminated by upwind applications.

Released December 31, 2020 08:56 EST

2020, Diseases of Aquatic Organisms

Mark A Matsche, Vicki S. Blazer, Erin Pulster, Patricia M. Mazik

Recent surveys of white perch Morone americana from Chesapeake Bay revealed a high prevalence of hepatic and biliary lesions, including neoplasia, and bile duct parasites. Here, we describe lesions in the liver and gallbladder and evaluate for statistical associations between lesions, parasites, and biomarkers of chemical exposure in fish from two tributaries of Chesapeake Bay, USA. Fish were collected from an estuarine site in the Choptank River (n = 122, ages 3-11), a tributary with extensive agriculture within the watershed, and the Severn River (n = 131, ages 2-16), a tributary with extensive urban development. Passive integrative samplers were deployed at the fish collection site and an upstream, non-tidal site in each river for 30 days. Intrahepatic biliary lesions observed in fish from both rivers included neoplasia (23.3%), dysplasia (16.2%), hyperplasia (46.6%), cholangitis (24.9%) and dilated ducts containing plasmodia of Myxidium sp. (24.9%). Hepatocellular lesions included foci of hepatocellular alterations (FHA, 15.8%) and neoplasia in 4 Severn River fish (2.3%). Age of fish and Myxidium sp. infections were significant risk factors for proliferative and neoplastic biliary lesions, age alone was a risk factor for FHA, and Goussia bayae infections were associated with cholangitis and cholecystitis. Lesion prevalence was higher in fish from the Severn River, which contained higher concentrations of polycyclic aromatic hydrocarbons (PAH), organochlorine pesticides, and brominated diphenyl ethers. Metabolite biomarkers indicated higher PAH exposures to Severn River fish. The potential roles of contaminant exposures and Myxidium sp. as a tumor promoter are discussed.

Released December 31, 2020 08:06 EST

2020, Chelonian Conservation and Biology (19) 217-235

Gregory A Geller, Gary S Casper, Brian J. Halstead

Released December 31, 2020 08:01 EST

2020, Northwestern Naturalist (101) 194-209

Brian J. Halstead, Caren S. Goldberg, Robert B Douglas, Patrick M. Kleeman, David W Ulrich

Released December 31, 2020 07:28 EST

2020, Herpetological Conservation and Biology (15) 597-610

David Pilliod, Lisa A. Hallock, Mark P. Miller, Thomas D. Mullins, Susan M. Haig

Conservation of wide-ranging species is aided by population genetic information that provides insights into adaptive potential, population size, interpopulation connectivity, and even extinction risk in portions of a species range. The Striped Whipsnake (Masticophis taeniatus) occurs across 11 western U.S. states and into Mexico but has experienced population declines in parts of its range, particularly in the state of Washington. We analyzed nuclear and mitochondrial DNA extracted from 192 shed skins, 63 muscle tissue samples, and one mouth swab to assess local genetic diversity and differentiation within and between the last known whipsnake populations in Washington. We then placed that information in a regional context to better understand levels of differentiation and diversity among whipsnake populations in the northwestern portion of the range of the species. Microsatellite data analyses indicated that there was comparable genetic diversity between the two extant Washington populations, but gene flow may be somewhat limited. We found moderate to high levels of genetic differentiation among states across all markers, including five microsatellites, two nuclear genes, and two mitochondrial genes. Pairwise state-level comparisons and dendrograms suggested that Washington whipsnakes are most closely related to those in Oregon, and distinct from Idaho, Nevada, and Utah, approximately following an isolation by distance model. We conclude that Washington populations of whipsnakes have experienced recent isolating events, but they have yet to lose genetic diversity. The longevity and high vagility of the species may provide opportunity for conservation of whipsnakes in the state as long as shrubland habitat is available

Released December 31, 2020 07:13 EST

2020, Journal of Parasitology (106) 843-853

Mai Fahmy, Kalani Williams, Michael Tessler, Sarah R. Weiskopf, Evon Hekkala, Mark E. Siddall

Released December 30, 2020 15:55 EST

1985, Water Data Report MD-DE-84-1

R.W. James, R.H. Simmons, B.F. Strain

No abstract available.

Released December 30, 2020 15:25 EST

1984, Water Data Report MD-DE-83-1

R.W. James, R.H. Simmons, B.F. Strain

No abstract available. 

Released December 30, 2020 15:15 EST

1982, Water Data Report MD-DE-81-1

U.S. Geological Survey

No abstract available.

Released December 30, 2020 15:10 EST

1981, Water Data Report MD-DE-80-1

U.S. Geological Survey

No abstract available.

Released December 30, 2020 15:05 EST

1978, Water Data Report MD-DE-77-1

U.S. Geological Survey

No abstract available. 

Released December 30, 2020 14:55 EST

1980, Water Data Report MD-DE-79-1

U.S. Geological Survey

No abstract available.

Released December 30, 2020 14:55 EST

1979, Water Data Report MD-DE-78-1

U.S. Geological Survey

No abstract available.

Released December 30, 2020 14:40 EST

1977, Water Data Report MD-DE-76-1

U.S. Geological Survey

No abstract available.

Released December 30, 2020 14:35 EST

1976, Water Data Report MD-DE-75-1

U.S. Geological Survey

No abstract available. 

Released December 30, 2020 14:30 EST

1975, Water Data Report MD-DE-74-2

U.S. Geological Survey

No abstract available.

Released December 30, 2020 14:30 EST

1975, Water Data Report MD-DE-74-1

U.S. Geological Survey

No abstract available. 

Released December 30, 2020 14:05 EST

1975, Water Data Report MD-DE-73-2

U.S. Geological Survey

No abstract available. 

Released December 30, 2020 13:55 EST

1975, Water Data Report MD-DE-72-2

U.S. Geological Survey

No abstract available.

Released December 30, 2020 13:55 EST

1974, Water Data Report MD-DE-73-1

U.S. Geological Survey

No abstract available. 

Released December 30, 2020 13:55 EST

1973, Water Data Report MD-DE-72-1

U.S. Geological Survey

No abstract available.

Released December 30, 2020 13:35 EST

1974, Water Data Report MD-DE-71-2

U.S. Geological Survey

No abstract available.

Released December 30, 2020 13:30 EST

1972, Water Data Report MD-DE-71-1

U.S. Geological Survey

No abstract available.

Released December 30, 2020 13:15 EST

2020, Scientific Investigations Report 2020-5118

John H. Ellis, Derek W. Ryter, Leland T. Fuhrig, Kyle W. Spears, Shana L. Mashburn, Ian M.J. Rogers

The Washita River alluvial aquifer is a valley-fill and terrace alluvial aquifer along the valley of the Washita River in western Oklahoma that provides a productive source of groundwater for agricultural irrigation and water supply. The Oklahoma Water Resources Board (OWRB) has designated the westernmost section of the aquifer in Roger Mills and Custer Counties, Okla., as reach 1 of the Washita River alluvial aquifer; reach 1 is the focus of this report. The OWRB issued an order on November 13, 1990, that established the maximum annual yield (MAY; 120,320 acre-feet per year [acre-ft/yr]) and equal-proportionate-share (EPS) pumping rate (2.0 acre-feet per acre per year [(acre-ft/acre)/yr]) for reach 1 of the Washita River alluvial aquifer. The MAY and EPS were based on hydrologic investigations that evaluated the effects of potential groundwater withdrawals on groundwater availability in the Washita River alluvial aquifer. Every 20 years, the OWRB is statutorily required to update the hydrologic investigation on which the MAY and EPS were based. Because 30 years have elapsed since the last order was issued, the U.S. Geological Survey, in cooperation with the OWRB, conducted a new hydrologic investigation and evaluated the effects of potential groundwater withdrawals on groundwater flow and availability in the Washita River alluvial aquifer.

The Washita River is the primary source of inflow to Foss Reservoir, a Bureau of Reclamation reservoir constructed in 1961 for flood control, water supply, and recreation. Foss Reservoir provides water for Bessie, Clinton, New Cordell, and Hobart, Okla. Nearly 98 percent of the total groundwater use from the Washita River alluvial aquifer during 1967 to 2015 was for irrigation; other uses of groundwater in the study area include public supply, mining, and agriculture.

A hydrogeologic framework was developed for the Washita River alluvial aquifer and included the physical characteristics of the aquifer, the geologic setting, the hydraulic properties of hydrogeologic units, the potentiometric surface (water table), and groundwater-flow directions at a scale that captures the regional controls on groundwater flow. The Washita River alluvial aquifer consists of alluvium and terrace deposits that were transported primarily by water and range from clay to gravel in size. The terrace includes windblown deposits of silt size and, in some cases, contains gravel laid down at several levels along former courses of present-day rivers.

A conceptual flow model is a simplified description of the aquifer system that includes hydrologic boundaries, major inflow and outflow sources of the groundwater-flow system, and a conceptual water budget with the estimated mean flows between those hydrologic boundaries. During the study period 1980–2015, mean annual groundwater withdrawals, predominantly used for agricultural irrigation, totaled 5,502 acre-ft/yr, or 14 percent of aquifer outflows. When applied across the 132-square-mile aquifer area used for modeling purposes (84,366 acres), mean annual recharge of 3.15 inches per year corresponds to a mean annual recharge volume of 22,169 acre-ft/yr, or 56 percent of aquifer inflows. The annual saturated-zone evapotranspiration outflow was 11,828 acre-ft/yr for the Washita River alluvial aquifer, or about 30 percent of aquifer outflows. For the Washita River alluvial aquifer, lateral flow was 17,157 acre-ft/yr, or 44 percent of the aquifer inflows. The conceptual flow model and hydrogeologic framework were used to conceptualize, design, and build the numerical groundwater-flow model.

A numerical groundwater-flow model of the Washita River alluvial aquifer was constructed by using MODFLOW-2005. The Washita River alluvial aquifer groundwater-model grid was spatially discretized into 350-foot (ft) cells and two layers. Layer 1 represented the undifferentiated alluvium and terrace deposits of Quaternary age, and layer 2 represented the bedrock of Permian age, which was given a uniform nominal thickness of 100 ft. The groundwater-simulation period was temporally discretized into 433 monthly transient stress periods, representing January 1980 to December 2015. An initial 365-day steady-state stress period was configured to represent mean annual inflows and outflows from the Washita River alluvial aquifer for the study period. The groundwater-flow model was calibrated manually and by automated adjustment of model inputs by using PEST++. Calibration targets for the Washita River alluvial aquifer model included groundwater-level observations and reservoir-stage observations, as well as base-flow and stream-seepage estimates.

Three groundwater-availability scenarios were used in the calibrated groundwater model to (1) estimate the EPS pumping rate that retains the saturated thickness that meets the minimum 20-year life of the aquifer, (2) quantify the effects of projected pumping rates on groundwater storage over a 50-year period, and (3) evaluate how projected pumping rates extended 50 years into the future and sustained hypothetical drought conditions over a 10-year period affect base flow and groundwater in storage. The results of the groundwater-availability scenarios could be used by the OWRB to reevaluate the established MAY of groundwater from the Washita River alluvial aquifer.

EPS scenarios for the Washita River alluvial aquifer were run for periods of 20, 40, and 50 years. The 20-, 40-, and 50-year EPS pumping rates under normal recharge conditions were 1.7, 1.6, and 1.6 (acre-ft/acre)/yr, respectively. Given the aquifer area used for modeling purposes (84,366 acres), these rates correspond to annual yields of 142,579, 134,986, and 134,986 acre-ft/yr, respectively. Groundwater storage at the end of the 20-year EPS scenario was about 281,000 acre-feet (acre-ft), or about 306,000 acre-ft (52 percent) less than the starting storage. Considering the land-surface area of the Washita River alluvial aquifer and using a specific yield of 0.12, this decrease in storage was equivalent to a mean groundwater-level decline of about 30 ft. The Washita River downstream from Foss Reservoir and most of the streams in the study area were dry at the end of the 20-year EPS scenario. Foss Reservoir stage was below the dead-pool stage of 1,597 ft after about 7 years of pumping in the 20-year EPS scenario.

Four projected 50-year groundwater-use scenarios were used to simulate the effects of selected well withdrawal rates on groundwater storage in the Washita River alluvial aquifer. These four scenarios used (1) no groundwater use, (2) groundwater use at the 2015 pumping rate, (3) mean groundwater use for the simulation period, and (4) increasing groundwater use. Groundwater storage after 50 years with no groundwater use was 545,249 acre-ft, or 693 acre-ft (0.1 percent) greater than the initial groundwater storage; this groundwater storage increase is equivalent to a mean groundwater-level increase of 0.1 ft. Groundwater storage at the end of the 50-year period with 2015 pumping rates was 543,831 acre-ft, or 723 acre-ft (0.1 percent) less than the initial storage; this groundwater storage decrease is equivalent to a mean groundwater-level decrease of 0.1 ft. Groundwater storage after 50 years with the mean pumping rate for the study period was 543,202 acre-ft, or 1,349 acre-ft (0.2 percent) less than the initial groundwater storage; this groundwater storage decrease is equivalent to a mean groundwater-level decrease of 0.1 ft. Groundwater storage at the end of the 50-year period with an increasing demand groundwater-pumping rate, which was 38 percent greater than the 2015 groundwater-pumping rate, was 542,584 acre-ft, or 1,967 acre-ft (0.4 percent) less than the initial storage; this groundwater storage decrease is equivalent to a mean groundwater-level decrease of 0.2 ft.

A hypothetical 10-year-drought scenario was used to simulate the effects of a prolonged period of reduced recharge on groundwater storage in the Washita River alluvial aquifer and Foss Reservoir stage and storage. To simulate the hypothetical drought, recharge in the calibrated model was reduced by 50 percent during the simulated drought period (1983–1992). Groundwater storage at the end of the drought period in December 1992 was 562,000 acre-ft, or 36,000 acre-ft (6 percent) less than the groundwater storage of the calibrated groundwater model (598,000 acre-ft). At the end of the hypothetical drought, the largest changes in saturated thickness (as great as 43.5 ft) were in the area upgradient from Foss Reservoir, particularly in the terrace at the model boundary. Substantial decreases in the Foss Reservoir stage began during the fall of 1985 in conjunction with base-flow decreases of up to 100 percent at U.S. Geological Survey streamgage 07324200 Washita River near Hammon, Okla. These lake-stage declines outpaced groundwater-level declines in the surrounding aquifer. The minimum Foss Reservoir storage simulated during the drought period was 77,954 acre-ft, which was a decrease of 46 percent from the nondrought storage.

Released December 30, 2020 12:55 EST

2020, Open-File Report 2020-1148

Pamela J. Lombard, Janet R. Barclay, Dee-Ann E. McCarthy

Below average and infrequent rainfall from May through September 2020 led to an extreme hydrologic drought across much of New England, with some areas experiencing a flash drought, reflecting its quick onset. The U.S. Geological Survey (USGS) recorded record-low streamflow and groundwater levels throughout the region. In September, the U.S. Department of Agriculture (2020) declared Aroostook County in Maine and Hillsborough and Merrimack Counties in New Hampshire as crop disaster areas. By the beginning of October, 166 community water systems and 5 municipalities in New Hampshire, more than 100 municipalities in Massachusetts, and several community water supplies in Connecticut, Maine, and Rhode Island had mandatory water restrictions in place.

Released December 30, 2020 07:04 EST

2021, Soil Dynamics and Earthquake Engineering Journal (141)

Jawad Fayaz, Sanaz Rezaeian, Farzin Zareian

There is a need for benchmarking and validating simulated ground motions in order for them to be utilized by the engineering community. Such validation may be geared towards a specific ground motion simulation method, a target engineering application, and a specific location; the validation presented herein focuses on a bridge engineering application in southern California. Catalogs of simulated ground motions representing a 200,000-year forecast are selected from the Southern California Earthquake Center CyberShake version 15.12 database for five sites in Southern California (~20,000 unscaled ground motions per site). They are used in Non-Linear Time History Analysis (NLTHA) of four Ordinary Standard Bridge structures. For each site, these data are used to obtain simulation-based Engineering Demand Parameter (EDP) hazard curves. These are compared against EDP hazard curves that are constructed using conventional methods based on empirical models, i.e., using recorded ground motions through Incremental Dynamic Analysis and integration over the Intensity Measure (IM) hazard curve. The two sets of simulation-based and conventional EDP hazard curves are compared at various return periods. To further account for the differences between simulated and recorded ground motions, direct comparisons are also made between IM hazard curves for simulated and recorded catalogs, as well as the EDP versus IM data obtained from NLTHA of the bridges. We observe that CyberShake simulates motions that yield similar EDP values compared to empirical data for shorter return periods. For longer return periods, however, EDPs from the simulation-based analysis tend to be lower than the EDPs obtained from utilizing recorded ground motions for short-period bridges, while the opposite is the case for long-period bridges. It is recommended that validation efforts go beyond IM levels and also include comparisons of the relations between IMs and EDPs. Finally, site-specific relations are proposed that correlate the ratio between the two types of EDPs (simulation-based and conventional) with the hazard level, shallow site condition, and site basin depth.

Released December 30, 2020 07:00 EST

2021, Journal of Volcanology and Geothermal Research (410)

Tim R. Orr, Richard W. Hazlett, Liliana G. DeSmither, James P. Kauahikaua, Ben Gaddis

Released December 29, 2020 16:50 EST

2020, Open-File Report 2020-1142

Li H. Erikson, Ann E. Gibbs, Bruce M. Richmond, Curt D. Storlazzi, Benjamin M. Jones, Karin Ohman

Executive Summary

Arey Lagoon, located in eastern Arctic Alaska, supports a highly productive ecosystem, where soft substrate and coastal wet sedge fringing the shores are feeding grounds and nurseries for a variety of marine fish and waterfowl. The lagoon is partially protected from the direct onslaught of Arctic Ocean waves by a barrier island chain (Arey Island) which in itself provides important habitat for migratory shorebirds and waterfowl. In this work, numerically modeled waves and water levels are computed under the provision of sea-level rise and changing conditions brought about by 21st century climate variability. Model results, supported by observations, are used to assess the stability of the barrier chain and spatiotemporal changes in flood patterns across fringing coastal wet sedge areas. The results aim to support studies that investigate the possibility of new biological succession trajectories and loss or increase of habitat areas. 

Released December 29, 2020 07:40 EST

2020, Report

Samuel Levi Helmuth, Evan Martin, Mary K. V. Hodges, Duane E. Champion

The geologic map of the Butte City 7.5’ quadrangle is based on mapping summarized in the 1:100,000 scale map of the Idaho National Laboratory, U.S. Geological Survey Miscellaneous Investigations Map I-2330, by Kuntz and others, 1994. New surficial geologic mapping was completed by National Association of Geoscience Teachers (NAGT) interns, Evan Martin (2015) and Samuel Helmuth (2017). Previously published maps and associated data, by various authors, including Kuntz, M.A., Betty Skipp, M.A. Lanphere, W.E. Scott, K.L. Pierce, G.B. Dalrymple, L.A. Morgan, D.E. Champion, G.F. Embree, W.R. Page, R.P. Smith, W.R. Hackett, and D.W. Rodgers from 1994 to 2017, were incorporated into this project. The U. S. Geological Survey (USGS) Idaho National Laboratory Project Office, a field office of the Idaho Water Science Center, conducts subsurface investigations to study the Snake River aquifer at the Idaho National Laboratory. Many subsurface basalts erupted from vents exposed at the surface. Tracing the flows from the surface to the subsurface provides data for numerical models of groundwater flow and contaminant transport.

Released December 29, 2020 07:38 EST

2021, Book chapter, Galapagos giant tortoises—Biodiversity of world—Conservation from genes to landscapes

Stephen Blake, Charles B. Yackulic, Freddy Cabrera, Sharon L. Deem, Diego Ellis-Soto, James P. Gibbs, Franz Kummeth, Martin Wikelski, Guillaume Bastille-Rousseau

(Yackulic) At first glance, the decision to study movement in Galapagos tortoises seems curious. Given the slow speed of tortoises and tendency to forage and rest as they move, it seems implausible that tortoises would string their slow bursts of activity together to accomplish large-scale movements. Nonetheless, as early as 1815 (Porter 1815), visitors to Galapagos have noted the propensity for tortoises to walk long distances along well used trails, leading to seasonal changes in the distribution of tortoises on the various islands of the Archipelago. In recent years, advances in the technology used to track animals have led to a better understanding of movement and the diversity of movement strategies among many animal taxa. This chapter focuses on the application of these technologies to study of movement in Galapagos tortoises. Recent work has shown not only the diversity of movement strategies employed by Galapagos tortoises, but also illustrated how movement can both cause and be a consequence of interaction between reproductive and foraging ecologies of tortoises and the presence of strong environmental gradients. Understanding how critical unimpeded movement is to the persistence of Galapagos tortoises also informs efforts to maintain connectivity to, and suitable habitat within, tortoise range outside of protected areas.

Released December 29, 2020 07:17 EST

2020, Geophysical Journal International

M.-A. Meier, P. Ampuero, Elizabeth S. Cochran, Morgan T. Page

To what extent can the future evolution of an ongoing earthquake rupture be predicted? This question of fundamental scientific and practical importance has recently been addressed by studies of teleseismic source time functions (STFs) but reaching contrasting conclusions. One study concludes that the initial portion of STFs is the same regardless of magnitude. Another study concludes that the rate at which earthquakes grow increases systematically and strongly with final event magnitudes. Here we show that the latter reported trend is caused by a selection bias towards events with unusually long durations, and by estimates of STF growth made when the STF is already decaying. If these invalid estimates are left out, the trend is no longer present, except during the first few seconds of the smallest events in the dataset, Mw5–6.5, for which the reliability of the STF amplitudes is questionable. Simple synthetic tests show that the observations are consistent with statistically indistinguishable growth of smaller and larger earthquakes. A much weaker trend is apparent among events of comparable duration, but we argue that its significance is not resolvable by the current data. Finally, we propose a nomenclature to facilitate further discussions of earthquake rupture predictability and determinism.

Released December 29, 2020 07:14 EST

2021, Diversity

Deborah Mardeane Epperson, Craig R. Allen, Katharine F.E. Hogan

Released December 29, 2020 07:00 EST

2021, Environmental Science and Technology (55) 974-984

J.E. Cavallin, William A. Battaglin, Jon Beihoffer, Bradley D. Blackwell, Paul Bradley, AR Cole, Drew R. Ekman, R Hofer, J Kinsey, Kristen Keteles, R Weissinger, Dana L. Winkelman, Daniel L. Villeneuve

Monitoring of the Colorado River near the Moab, Utah, wastewater treatment plant (WWTP) outflow has detected pharmaceuticals, hormones, and estrogen-receptor (ER)-, glucocorticoid receptor (GR)-, and peroxisome proliferator-activated receptor-gamma (PPARγ)-mediated biological activities. The aim of the present multi-year study was to assess effects of a WWTP replacement on bioactive chemical (BC) concentrations. Water samples were collected bimonthly, pre- and post-replacement, at 11 sites along the Colorado River upstream and downstream of the WWTP and analyzed for in vitro bioactivities (e.g., agonism of ER, GR, and PPARγ) and BC concentrations; fathead minnows were cage deployed pre- and post-replacement at sites with varying proximities to the WWTP. Before the WWTP replacement, in vitro ER (24 ng 17β-estradiol equivalents/L)-, GR (60 ng dexamethasone equivalents/L)-, and PPARγ-mediated activities were detected at the WWTP outflow but diminished downstream. In March 2018, the WWTP effluent was acutely toxic to the fish, likely due to elevated ammonia concentrations. Following the WWTP replacement, ER, GR, and PPARγ bioactivities were reduced by approximately 60–79%, no toxicity was observed in caged fish, and there were marked decreases in concentrations of many BCs. Results suggest that replacement of the Moab WWTP achieved a significant reduction in BC concentrations to the Colorado River.

Released December 28, 2020 12:00 EST

2020, Open-File Report 2020-1139

Laurel E. Low, Hilary A. Neckles, James E. Lyons, Jessica L. Nagel, Susan C. Adamowicz, Toni Mikula, Kristina Vagos, Richard Potvin

Structured decision making is a systematic, transparent process for improving the quality of complex decisions by identifying measurable management objectives and feasible management actions; predicting the potential consequences of management actions relative to the stated objectives; and selecting a course of action that maximizes the total benefit achieved and balances tradeoffs among objectives. The U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service, applied an existing, regional framework for structured decision making to develop a prototype tool for optimizing tidal marsh management decisions at the Stewart B. McKinney National Wildlife Refuge in Connecticut. Refuge biologists, refuge managers, and research scientists identified multiple potential management actions to improve the ecological integrity of two marsh management units within the refuge and estimated the outcomes of each action in terms of performance metrics associated with each management objective. Value functions previously developed at the regional level were used to transform metric scores to a common utility scale, and utilities were summed to produce a single score representing the total management benefit that would be accrued from each potential management action. Constrained optimization was used to identify the set of management actions, one per marsh management unit, that would maximize total management benefits at different cost constraints at the refuge scale. Results indicated that, for the objectives and actions considered here, total management benefits may increase consistently up to approximately $1,190,000, but that further expenditures may yield diminishing return on investment. Management actions in optimal portfolios at total costs less than $1,190,000 included controlling avian predators in both management units, managing stormwater on lands adjacent to one marsh management unit, and removing a tide gate and breaching a dike to improve tidal flow in the other marsh management unit. The management benefits were derived from expected increases in the numbers of spiders (as an indicator of trophic health) and tidal marsh obligate birds, and an expected decrease in the use of herbicides to control invasive vegetation. The prototype presented here provides a framework for decision making at the Stewart B. McKinney National Wildlife Refuge that can be updated as new data and information become available. Insights from this process may also be useful to inform future habitat management planning at the refuges.

Released December 28, 2020 07:09 EST

2020, Native Plants Journal (21) 268-274

Daniel E. Winkler, Robert Massatti, Sasha Reed

Released December 28, 2020 07:08 EST

2020, Bulletin of the American Meteorological Society (101)

Elinor Martin, Renee McPherson, Emma Kuster, Aparna Bamzai

Released December 28, 2020 06:49 EST

2020, PLoS ONE (15)

Meredith B. Nevers, Katarzyna Przybyla-Kelly, Dawn A. Shively, Charles C. Morris, Joshua Dickey, Muruleedhara Byappanahalli

Environmental DNA (eDNA) can be used for early detection, population estimations, and assessment of potential spread of invasive species, but questions remain about factors that influence eDNA detection results. Efforts are being made to understand how physical, chemical, and biological factors—settling, resuspension, dispersion, eDNA stability/decay—influence eDNA estimations and potentially population abundance. In a series of field and controlled mesocosm experiments, we examined the detection and accumulation of eDNA in sediment and water and the transport of eDNA in a small stream in the Lake Michigan watershed, using the invasive round goby fish (Neogobius melanostomus) as a DNA source. Experiment 1: caged fish (average n = 44) were placed in a stream devoid of round goby; water was collected over 24 hours along 120-m of stream, including a simultaneous sampling event at 7 distances from DNA source; stream monitoring continued for 24 hours after fish were removed. Experiment 2: round goby were placed in laboratory tanks; water and sediment were collected over 14 days and for another 150 days post-fish removal to calculate eDNA shedding and decay rates for water and sediment. For samples from both experiments, DNA was extracted, and qPCR targeted a cytochrome oxidase I gene (COI) fragment specific to round goby. Results indicated that eDNA accumulated and decayed more slowly in sediment than water. In the stream, DNA shedding was markedly lower than calculated in the laboratory, but models indicate eDNA could potentially travel long distances (up to 50 km) under certain circumstances. Collectively, these findings show that the interactive effects of ambient conditions (e.g., eDNA stability and decay, hydrology, settling-resuspension) are important to consider when developing comprehensive models. Results of this study can help resource managers target representative sites downstream of potential invasion sites, thereby maximizing resource use.

Released December 25, 2020 07:31 EST

2021, Rangeland Ecology & Management (75) 17-28

Amy Symstad, Deborah A. Buhl, Daniel J Swanson

Concern about the impacts of two invasive annual brome grasses (cheatgrass and Japanese brome, Bromus tectorum L. and B. japonicus Thunb. ex Murray) on the mixed-grass prairie of North America's northern Great Plains (NGP) is growing. Cheatgrass is well known west of the NGP, where replacement of fire-intolerant, native sagebrush steppe by fire-prone, exotic annual grasslands is widespread. Consequently, fire is often not considered as a tool for controlling annual bromes. This should not be the case in the NGP, where mixed-grass prairie is adapted to frequent fires. Fire's efficacy may vary with the degree of invasion, though; suppressing postfire annual brome populations or enhancing the native plant community may improve postfire annual brome control in highly invaded areas. To test this, we performed an experiment at two sites to evaluate the relative effectiveness of prescribed fire alone, fire followed by imazapic application and fire followed by native seeding across a pretreatment invasion gradient of annual brome-to-native species cover ranging from 0.05 to 2.35. Fall-prescribed fire alone greatly reduced annual bromes, but by the second yr after treatment the effect was significant only at invasion ratios < 1.2. Postfire imazapic application reduced annual bromes even further than fire alone, but only for 1 yr at the less invaded site and only at invasion ratios > 1.2 in yr 2 at the other site. Native species cover and total species richness responded positively to all treatments, but the degree of their response varied along the invasion gradient, between sites, with time since treatment and among treatments. Also, at one site, fire yielded a lagged stimulation of short-lived, exotic forbs. Seeding had little effect. Fire is an effective tool for reducing annual bromes in the NGP at lower invasion levels, but more tools are needed for long-term, effective control at highly invaded sites.

Released December 25, 2020 06:53 EST

2021, Biological Conservation (253)

Joshua R. Ennen, Mickey Agha, Sarah C. Sweat, Wildredo A. Matamoros, Jeffrey E. Lovich, John B. Iverson, Anders G.J. Rhodin, Robert C. Thomson, H. Bradley Shaffer, Christopher W. Hoagstrom

Conservation planners use a variety of decision-making tools, many of which require identifying and prioritizing spatial units based on their biodiversity and levels of imperilment. Turtles are highly imperiled, but present schemes for determining global priority areas are focused mostly on broad regional scales. We conduct the first global evaluation of turtle biodiversity and imperilment at a sub-basin level to identify geographically smaller areas of high conservation value, and compare with these existing prioritizations. We employed two spatial analyses—bivariate maps and local indicator of spatial association (LISA)—to identify and prioritize sub-basin clusters based on multiple biodiversity and conservation metrics in addition to species richness. Most high-priority sub-basin clusters were located along tropical and subtropical coastlines. A new area of global significance for turtle conservation was identified in southwest India. Many sub-basins of the Indomalayan Realm were clustered as high or intermediate priority, with large clusters of high-priority sub-basins also in tropical Australasia. Other high and intermediate priority sub-basin clusters were found in the Afrotropical, Neotropical, and Nearctic realms, often in previously recognized turtle biodiversity hotspots. Many conservation-priority sub-basins with high turtle-species richness and endemism are in lowland and coastal areas where endemics (some from ancient lineages) are imperiled in association with a high human footprint. Our findings reiterate the global significance of Asia as a key area of chelonian conservation need, while identifying focal areas across the globe where the need for targeted turtle conservation is especially great.

Released December 24, 2020 07:19 EST

2021, Applied Geochemistry (126)

MaryLynn Musgrove

Groundwater samples from 32 principal aquifers across the United States (U.S.) provide a broad spatial scope of the occurrence and distribution of strontium (Sr) and are used to assess environments and factors that influence Sr concentration. Strontium is a common trace element in soils, rocks, and water and is ubiquitous in groundwater with detectable concentrations in 99.8% of samples (n=4,824; median = 225 μg/L). Concentrations in 2.3% of samples exceeded the 4,000 μg/L health-based screening level. The relative importance of controlling factors on Sr concentration are spatially variable and partly dependent on the type of groundwater well. Three case settings illustrate controls on Sr concentration. For drinking-water supply wells, most high concentrations (>4,000 μg/L) were measured in samples from carbonate aquifers that resulted from water-rock interaction with Sr-bearing rocks and minerals. High Sr concentrations from monitoring wells were more common in unconsolidated sand and gravel aquifers in arid or semi-arid setting where shallow groundwater is affected by irrigation and evaporative concentration of dissolved constituents in combination with lithologic or applied Sr sources. Upwelling saline groundwater is also a source of Sr source in some locations. Total dissolved solids concentration is an indicator of high Sr in all settings. An estimated 2.2 million people in the conterminous U.S. are potentially supplied water from public-supply wells with high Sr concentration, ∼86% of whom use carbonate aquifers (with > half supplied by the Floridan aquifer system). An additional 120,000 people are potentially supplied high-Sr-concentration water from domestic wells, >half of whom (∼58%) are in Texas. This study markedly expands the coverage of previous surveys of Sr in groundwater and is of interest given potential adverse human-health effects related to elevated concentrations of Sr and consideration of Sr for drinking-water regulation. Case settings with elevated Sr described for U.S. groundwater are likely indicative of settings and processes affecting Sr concentration in groundwater globally.

Released December 24, 2020 06:57 EST

2020, Virus Evolution

Nichola J. Hill, Lacy M. Smith, Sabir B. Muzaffar, Jessica L. Nagel, Diann Prosser, Jeffery D. Sullivan, Kyle A. Spragens, Carlos A. DeMattos, Cecilia C. Demattos, Lu'ay El Sayed, Kiraz Erciyas-Yavuz, C. Todd Davis, Joyce Jones, Zoltan Kis, Ruben O. Donis, Scott H. Newman, John Y. Takekawa

Understanding transmission dynamics that link wild and domestic animals is a key element of predicting the emergence of infectious disease, an event that has highest likelihood of occurring wherever human livelihoods depend on agriculture and animal trade. Contact between poultry and wild birds is a key driver of the emergence of highly pathogenic avian influenza (HPAI), a process that allows for host-switching and accelerated reassortment, diversification and spread of virus between otherwise unconnected regions. This study addresses questions relevant to the spillover of HPAI at a transmission hotspot: what is the nature of the wild bird-poultry interface in Egypt and adjacent Black Sea-Mediterranean countries and how has this contributed to outbreaks occurring worldwide? Using a spatio-temporal model of infection risk informed by satellite tracking of waterfowl and viral phylogenetics, this study identified ecological conditions that contribute to spillover in this understudied region. Results indicated that multiple ducks (Northern Shoveler and Northern Pintail) hosted segments that shared ancestry with HPAI H5 from both clade 2.2.1 and clade 2.3.4 supporting the role of Anseriformes in linking viral populations in East Asia and Africa over large-distances. Quantifying the interface between wild ducks and H5N1-infected poultry revealed an increasing interface in late winter peaking in early spring when ducks expanded their range before migration, with key differences in the timing of poultry contact risk between local and long-distance migrants.

Released December 23, 2020 10:20 EST

2020, Techniques and Methods 11-D3

Michael L. Noll, Paul H. Rydlund, Jr.

With the advent of highly precise total stations and modern surveying instrumentation, trigonometric leveling has become a compelling alternative to conventional leveling methods for establishing vertical-control networks and for perpetuating a datum to field sites. Previous studies of trigonometric-leveling measurement uncertainty proclaim that first-, second-, and third-order accuracies may be achieved if strict leveling protocols are rigorously observed. Common field techniques to obtain quality results include averaging zenith angles and slope distances observed in direct and reverse instrument orientation (F1 and F2, respectively), multiple sets of reciprocal observations, quality meteorological observations to correct for the effects of atmospheric refraction, and electronic distance measurements that generally do not exceed 500 feet. In general, third-order specifications are required for differences between F1 and F2 zenith angles and slope distances; differences between redundant instrument-height measurements; section misclosure determined from reciprocal observations; and closure error for closed traverse. For F1 observations such as backsight check and check shots, the construction-grade specification is required for elevation differences between known and observed values.

Recommended specifications for trigonometric-leveling equipment include a total station instrument with an angular uncertainty specification less than or equal to plus or minus 5 arc-seconds equipped with an integrated electronic distance measurement device with an uncertainty specification of less than or equal to plus or minus 3 millimeters plus 3 parts per million. A paired data collector or integrated microprocessor should have the capability to average multiple sets of measurements in direct and reverse instrument orientation. Redundant and independent measurements by the survey crew and automated or manual reduction of slant heights to the vertical equivalent are recommended to obtain quality instrument heights. Horizontal and vertical collimation tests should be conducted daily during trigonometric-leveling surveys, and electronic distance-measurement instruments should be tested annually on calibrated baselines maintained by the National Geodetic Survey. Specifications that were developed by the National Geodetic Survey for geodetic leveling have been adapted by the U.S. Geological Survey (USGS) for the purpose of developing standards for trigonometric leveling, which are identified as USGS Trigonometric Level I (TL I), USGS Trigonometric Level II (TL II), USGS Trigonometric Level III (TL III), and USGS Trigonometric Level IV (TL IV). TL I, TL II, and TL III surveys have a combination of first, second, and third geodetic leveling specifications that have been modified for plane leveling. The TL III category also has specifications that are adapted from construction-grade standards, which are not recognized by the National Geodetic Survey for geodetic leveling. A TL IV survey represents a leveling approach that does not generally meet criteria of a TL I, TL II, or TL III survey.

Site conditions, such as highly variable topography, and the need for cost-effective, rapid, and accurate data collection in response to coastal or inland flooding have emphasized the need for an alternative approach to conventional leveling methods. Trigonometric leveling and the quality-assurance methods described in this manual will accommodate most site and environmental conditions, but measurement uncertainty is potentially variable and dependent on the survey method. Two types of closed traverse surveys have been identified as reliable methods to establish and perpetuate vertical control: the single-run loop traverse and double-run spur traverse. Leveling measurements for a double-run spur traverse are made in the forward direction from the origin to the destination and are then retraced along the same leveling route in the backward direction, from the destination to the origin. Every control point in a double-run spur traverse is occupied twice. Leveling measurements for a single-run loop traverse are made in the forward direction from the origin point to the destination, and then from the destination to the origin point, along a different leveling route. The only point that is redundantly occupied for the single-run loop traverse is the origin. An open traverse method is also considered an acceptable approach to establish and perpetuate vertical control if the foresight prism height is changed between measurement sets to ensure at least two independent observations. A modified version of leap-frog leveling is recommended for all traverse surveys because it reduces measurement uncertainty by forcing the surveying instrumentation into a level and centered condition over the ground point as the instrumentation is advanced to the objective. Sideshots are considered any radial measurement made from the total station that is not part of a traverse survey. F1 and F2 observations are recommended for sideshots measurements for projects that require precise elevations. Quality-assurance measurements made in F1 from the station to network-control points should be considered for surveys that require a high quantity of sideshots.

The accuracy of a trigonometric-leveling survey essentially depends on four components (1) the skill and experience of the surveyor, (2) the environmental or site conditions, (3) the surveying method, and (4) the quality of the surveying instrumentation. Although components one and two can sometimes be difficult to evaluate and be highly variable, the objective of this manual is to disseminate information needed to identify, maintain, and operate quality land-surveying instrumentation, and to document procedures and best practices for preparing and executing precision trigonometric-leveling surveys in the USGS.

Released December 23, 2020 07:45 EST

2021, Conference Paper, WLF 2020: Understanding and reducing landslide disaster risk

Rex L. Baum

One of the challenges in assessing temporal and spatial aspects of landslide hazard using process-based models is estimating model input parameters, especially in areas where limited measurements of soil and rock properties are available. In an effort to simplify and streamline parameter estimation, development of a simple, rapid approach to sensitivity analysis relies on field measurements of landslide characteristics, especially slope and depth. This method is demonstrated for a case study in Puerto Rico where widespread destruction resulted from tens of thousands of debris flows induced by Hurricanes Irma and María in Puerto Rico in 2017. The approach can be applied to estimation of shear strength as well as hydrologic parameters that control infiltration and flow of water in the subsurface and ultimately the timing of landslides resulting from heavy rainfall. Results narrow the possible range of cohesion and friction parameters as well as hydraulic conductivity and other soil water parameters by counting the fraction of field observations that can be explained by each combination of parameters. For cases studied in Puerto Rico, the method identified combinations of cohesion and friction values that explain more than 80–90% of observed landslide source areas.

Released December 23, 2020 07:22 EST

2021, Journal of Geophysical Research- Biogeosciences (126)

Fenix Garcia-Tigreros, Mihai Leonte, Carolyn D. Ruppel, Angel Ruiz-Angulo, DoongJoo Joung, Benjamin Young, John D. Kessler

Released December 22, 2020 19:01 EST

2020, Scientific Investigations Report 2020-5114

Eileen M. Kirsch

Floodplain forest on the upper Mississippi River (UMR), a unique habitat in the Midwest that is important for many bird species, has been reduced and is undergoing continued reduction and changes in structure and species diversity because of river engineering and invasive species. Hydrological changes are causing tree diversity to decline favoring Acer saccharinum (silver maple) and Fraxinus pennsylvanica (green ash). Invasive Phalaris arundinacea (reed canary grass, Phalaris) threatens tree regeneration, and recent Agrilus planipennis (emerald ash borer) arrival threatens to decimate the important ash component of the forest canopy. During the 1990s, virtually no information was available about breeding songbird species and abundances on the UMR floodplain forest from along many river miles and a broad range of forest situations (for example, mainland, island, edge, interior). From 1994 to 1997, we surveyed breeding birds and sampled vegetation at 391 random points on UMR floodplain forest along a latitudinal gradient from Red Wing, Minnesota, to Clinton, Iowa, to characterize bird assemblages and associations with gradients in forest structure at survey points (local scale) and land cover composition within a 200-meter radius of survey points (landscape scale).

Eighty-six bird species were detected during the study, but 28 species comprised 90 percent of all detections. Species that are typically associated with woodland edge or are tolerant of fragmentation were the most common: Setophaga ruticilla (American Redstart), Troglodytes aedon (House Wren), Turdus migratorius (American Robin), Quiscalus quiscula (Common Grackle), and Vireo gilvus (Warbling Vireo). Species typically associated with large forest patches—Setophaga cerulea (Cerulean Warbler), Hylocichla mustelina (Wood Thrush), and Dryocopus pileatus (Pileated Woodpecker)—were rare. Principal components analyses consistently described local habitat gradients related to canopy cover and Phalaris presence and described landscape gradients related to forest area and areas of open land cover types. However, nonmetric multidimensional scaling revealed no pattern in bird assemblages. Canonical correspondence analyses with local habitat variables for each year revealed that bird assemblages were affected by canopy cover, the presence of Phalaris, and the number of tree species. Four bird species were consistently associated with Phalaris presence or negatively with canopy cover, and no species were associated with the number of tree species variable. Although landscape variables were significantly related to the bird assemblage in canonical correspondence analyses, no bird species were consistently related to any landscape variable. These results indicate that there is one assemblage of forest birds on the UMR composed mainly of edge-tolerant species. Species associated with lower canopy cover and Phalaris presence may be favored to increase in abundance as canopy cover opens as trees die and Phalaris becomes more prevalent.

Released December 22, 2020 12:00 EST

2020, Scientific Investigations Map 3462

Gregory J. Walsh, Peter M. Valley, Thomas R. Armstrong, Nicholas M. Ratcliffe, Arthur J. Merschat, Beau J. Gentry

The bedrock geology of the 7.5- by 15-minute Springfield quadrangle consists of highly deformed and metamorphosed Mesoproterozoic through Devonian metasedimentary and meta-igneous rocks. In the west, Mesoproterozoic gneisses of the Mount Holly Complex are the oldest rocks and form the eastern side of the Chester dome. The Moretown slice structurally overlies the Chester dome along the Keyes Mountain thrust fault which represents the Ordovician Taconic suture (Red Indian Line) between Laurentian and Ganderian crust. The allochthonous Cambrian through Ordovician Moretown slice includes the Moretown and Cram Hill Formations and the North River Igneous Suite. Silurian and Devonian metasedimentary and metavolcanic rocks of the Connecticut Valley trough (CVT) unconformably overlie the Moretown slice. Ordovician to Silurian and Devonian metasedimentary and meta-igneous rocks of the New Hampshire sequence structurally overlie the CVT along the Devonian, Acadian Monroe thrust fault. The oldest part of the New Hampshire sequence consists of Ordovician metamorphosed volcanic, plutonic, and sedimentary rocks of the Bronson Hill arc including the Ammonoosuc Volcanics, the Partridge Formation, and the Oliverian Plutonic Suite. The Ammonoosuc Volcanics are the base of the exposed arc section in the map area. The Bronson Hill arc rocks are exposed in fault-bounded structural belts, including the Monroe thrust sheet, the Claremont belt, the Sugar River and Unity domes, and the footwall of the Brennan Hill thrust fault. Silurian to Devonian metasedimentary rocks of the Clough Quartzite, and Fitch and Littleton Formations unconformably overlie the Bronson Hill arc rocks. Devonian granitic and pegmatitic dikes and sills of the New Hampshire Plutonic Suite intruded previously deformed rocks.

Devonian, Acadian F₁ fold nappes have a sheath fold geometry and are truncated by multiple generations of faults. The Bronson Hill arc structurally overlies the CVT along the Acadian Monroe fault with preserved tectonic mélange in the footwall. Upright dome-stage F₂ folds post-date amphibolite facies metamorphism and locally developed into sheath folds in high-strain zones. F₃ folds exhibit sinistral rotation associated with Alleghanian lower-greenschist facies faults. Late Paleozoic Alleghanian to Mesozoic shear zones transpose stratigraphy, early structures, and peak metamorphic isograds. ⁴⁰Ar/³⁹Ar white-mica growth ages (300–250 million years before present [Ma]) indicate that retrograde deformation continued into the latest Paleozoic and earliest Mesozoic. Apatite fission track data show that brittle faults were active prior to about 100 Ma and experienced Late Cretaceous and even Paleocene re-activation.

The bedrock geology was mapped to study the tectonic history of the area and to provide a framework for ongoing characterization of the bedrock of Vermont and New Hampshire. This Scientific Investigations Map of the Springfield 7.5- x 15-minute quadrangle consists of sheets 1 and 2 as well as a geographic information system (GIS) database that includes bedrock geologic units, faults, outcrops, and structural geologic information. Sheet 1 of the report includes a bedrock geologic map, a correlation of map units, and a description of map units. Sheet 2 includes a discussion of the geology, references cited, two cross sections from the geologic map on sheet 1, a tectonic map showing major structural features, and a structural domain map showing the orientation of brittle features.

Released December 22, 2020 10:12 EST

2020, Scientific Investigations Report 2020-5127

Jared J. Trost, Anna-Turi Maher, William W. Simpkins, Alyssa N. Witt, James R. Stark, Justin Blum, Andrew M. Berg

Confined (or buried) aquifers of glacial origin overlain by till confining units provide drinking water to hundreds of thousands of Minnesota residents. The sustainability of these groundwater resources is not well understood because hydraulic properties of till that control vertical groundwater fluxes (leakage) to underlying aquifers are largely unknown. The U.S. Geological Survey, Iowa State University, Minnesota Geological Survey, and Minnesota Department of Health investigated hydraulic properties and groundwater flow through till confining units using field studies and heuristic MODFLOW simulations. Till confining units in the following late-Wisconsinan stratigraphic units (with locations in parentheses) were characterized: Des Moines lobe till of the New Ulm Formation (Litchfield, Minnesota), Superior lobe till of the Cromwell and Aitkin Formations (Cromwell, Minn.), and Wadena lobe till of the Hewitt Formation (hydrogeology field camp [HFC] near Akeley, Minn.). Pre-Illinoian till of the Good Thunder formation (Olivia, Minn.) was also characterized.

Hydraulic and geochemical field data were collected from sediment cores and a series of five piezometer nests. Each nest consisted of five to eight piezometers screened at short vertical intervals in hydrostratigraphic units including (if present) surficial aquifers, till confining units, confined/buried aquifers, and underlying bedrock. Till hydraulic conductivity was estimated from slug tests (horizontal [K_h]) and constant-rate aquifer tests in the confined aquifer (vertical [K_v]). Travel times through the till were evaluated with Darcy’s law and stable isotope concentrations. A series of heuristic MODFLOW simulations were used to evaluate groundwater fluxes through till across the range of till hydraulic properties and pumping rates observed at the field sites.

The field data demonstrated variability in hydraulic properties between and within till stratigraphic units horizontally and vertically. The variability in hydraulic properties within and between sites resulted in substantial differences in groundwater flux through till. A conceptual understanding that emerges from the vertical till profiles is that they are not homogeneous hydrostratigraphic units with uniform properties; rather, each vertical sequence is a heterogeneous mixture of glacial sediment with differing abilities to transmit water.

Till thicknesses varied from 60 to 166 feet, and till textures ranged from a sandy loam (Hewitt Formation, HFC site) to a silt loam/clay loam (Good Thunder formation, Olivia site). Till Kh varied by one to three orders of magnitude within each piezometer nest. Four piezometer nests had downward hydraulic gradients ranging from 0.04 to 0.56, and one nest had a slight upward hydraulic gradient of 0.02. The Cromwell, HFC, and Litchfield 1 sites were examples of “leaky” tills with high Kv (0.001 to 1.1 feet per day [ft/d]) and geometric mean Kh (0.03 to 0.07 ft/d) and extensive vertical hydraulic connectivity between the confined aquifer and the overlying till. Estimated groundwater travel times through these sites ranged from 1 to 81 years, and two of these sites had tritium throughout their till profiles. The tills at the other two sites, Olivia and Litchfield 2, were effective confining units that had low Kv (0.001 to 0.0005 ft/d) and geometric mean Kh (0.0002 to 0.004 ft/d). The till piezometers at these sites had no drawdown response to short-term (up to 10 hours for Olivia and up to 5 days for Litchfield) high-capacity pumping from the confined aquifer. Estimated groundwater travel times through the tills at these sites ranged from 165 to nearly 1,800 years, and tritium was only detected in the upper one-third of these till profiles. Across all sites, the till vertical anisotropy (ratio of K_h to K_v) ranged by four orders of magnitude from 0.05 at the Cromwell nest to 70 at the Litchfield 1 nest. Stable isotopes of oxygen and hydrogen indicate that groundwater throughout all five till profiles is younger than the last glacial advance into Minnesota at about 11,000 years ago.

The heuristic modeling demonstrated that, for understanding sustainability of groundwater pumping from confined aquifers, knowledge of till hydraulic properties is just as important as knowledge of aquifer hydraulic properties. Substantial differences in groundwater fluxes into and through till were observed across hydrogeologic settings representative of the field sites. Over long periods of time (hundreds of years), pumping-induced hydraulic gradients are established in confined aquifer systems and, even in low hydraulic conductivity tills, these pumping-induced hydraulic gradients increase leakage into and through till compared to ambient conditions.

In conclusion, groundwater flowing vertically downward through till confining units (leakage) replenishes water pumped from confined aquifers. Till hydraulic properties, such as those presented in this report, provide important information that can be used to quantify leakage rates through till. Till hydraulic properties are variable over short distances and profoundly affect leakage rates, demonstrating the importance of site-specific till hydraulic data for evaluating the sustainability of groundwater withdrawals from confined aquifers.

Released December 22, 2020 10:11 EST

2020, Techniques and Methods 7-C26

Jeremy T. White, Randall J. Hunt, Michael N. Fienen, John E. Doherty

PEST++ Version 5 extends and enhances the functionality of the PEST++ Version 3 software suite, providing environmental modeling practitioners access to updated Version 3 tools as well as new tools to support decision making with environmental models. Version 5 of PEST++ includes tools for global sensitivity analysis (PESTPP-SEN); least-squares parameter estimation with integrated first-order, second-moment parameter and forecast uncertainty estimation (PESTPP-GLM); an iterative, localized ensemble smoother (PESTPP-IES); and a tool for management optimization under uncertainty (PESTPP-OPT). Additionally, all PEST++ Version 5 tools have a built-in fault-tolerant, multithreaded parallel run manager and are model independent, using the same protocol as the widely used PEST software suite.

PEST++ Version 5 is consistent with PEST++ Version 3 conventions and design philosophy. The software’s emphasis continues to target efficient and optimized algorithms that have proven beneficial in decision-support settings and can accommodate large, highly parameterized problems. Expanded and new capabilities are now available to express uncertainty using Monte Carlo and analytical uncertainty approaches and allow evaluation of thousands to millions of parameters. New management optimization capabilities in Version 5 also allow environmental models to be used to answer management questions using multiple societal constraints in a risk-based framework.

The PEST++ Version 5 software suite can be compiled for Microsoft Windows® and Unix-based operating systems such as Apple and Linux®; the source code is available with a Microsoft Visual Studio® 2019 solution; and CMake support for all three operating system is also provided. PEST++ Version 5 continues to build a foundation for an open-source framework capable of producing model-independent, robust, and efficient decision-support tools for large environmental models. The functionality of each of the PEST++ tools are demonstrated on a simple example problem. Implications of decisions used when using the PEST++ suite tools are also discussed.

Released December 22, 2020 10:09 EST

2020, Professional Paper 1824-R

Timothy R. Klett, Janet K. Pitman

The U.S. Geological Survey (USGS) assessed the potential for undiscovered oil and gas resources of the Yenisey-Khatanga Basin Province as part of the USGS Circum-Arctic Resource Appraisal. The province is situated between the Taimyr-Kara high (Kara block, Central Taimyr fold belt, and South Taimyr fold belt) and the Siberian craton. The two assessment units (AUs) defined for this study—the Khatanga Saddle AU and the Yenisey-Khatanga Basin AU were assessed for undiscovered, technically recoverable, conventional resources. The estimated mean volumes of undiscovered resources for the Yenisey-Khatanga Basin Province are ~5.6 billion barrels of crude oil, ~100 trillion cubic feet of natural gas, and ~2.7 billion barrels of natural-gas liquids, all north of the Arctic Circle.

Released December 22, 2020 09:55 EST

2020, Open-File Report 2020-1133

Larry G. Mastin, Alexa R. Van Eaton, Hans F. Schwaiger

Hanford, Washington (USA) is the construction site of a multi-billion-dollar high-level nuclear waste treatment facility. This site lies 200 kilometers (km) east of Mount St. Helens (MSH), the most active volcano in the contiguous United States. Tephra from a future MSH eruption could pose a hazard to the air intake and filtration systems at this plant. In this report, we present a probabilistic estimate of the amount of tephra that could fall, and the concentrations of airborne ash that could occur at the Hanford Site during a future eruption. Mount St. Helens has produced four large explosive eruptions in approximately the past 500 years, suggesting that its annual probability of eruption (P₁) is roughly 4/500=0.008. Assuming that a large eruption occurs, we calculate the probability (P_3|1) of a given fall deposit thickness or airborne concentration at Hanford by running about 10,000 simulations of ash-producing eruptions using the atmospheric transport model Ash3d. In each simulation, we calculate the pattern of tephra dispersal, deposit thickness at Hanford, and airborne ash concentration at ground level. As input for each simulation, we choose meteorological conditions from a randomly chosen time in the historical record between 1980 and 2010, using data from the European Centre for Medium-Range Weather Forecasting (ECMWF) Reanalysis (ERA) Interim model. The volume (dense-rock equivalent) of each simulated eruption is randomly chosen from a uniform probability distribution on a log scale from the range of magma volumes (0.008–2.3 cubic kilometers [km³]) estimated for late Holocene eruptions at MSH. Plume heights and durations of each eruption are chosen using empirical correlations between volume, height, and eruption rate, which account for the fact that larger eruptions have higher plumes and last longer. We construct summary tables of final deposit thickness (T), maximum ground-level airborne concentration (C_max), and average ground-level airborne concentration (C_avg) during tephra-fall for each run. Each table is sorted and ranked by decreasing value of T, C_max, or C_avg. Conditional probabilities (P_3|1) are derived by dividing rank by n+1, where n is the total number of successful runs. For example, a deposit thickness of 5.10 centimeters (cm) from run 446 is ranked 123 of 9,785 successful runs, yielding P_3|1=123/9,786=0.01257. Its annual probability is P=P₁·P_3|1=0.008×0.01257=0.000101. By interpolation, the deposit thickness (T_10k) having an annual probability of 1 in 10,000 (P= 0.0001) is 5.11 cm. Analogous concentration values are C_max,10k=3,819 and C_avg,10k=1,513 milligrams per cubic meter (mg/m³), respectively. Independent calculations using the known mass accumulation rate of the deposit (=0.001–0.006 kilograms per square meter per second [kg/m²/s]), aggregate fall velocities (u=0.3–0.8 meters per second [m/s]), and the simple formula , yield similar results, although highly variable fall velocities add significant uncertainty. This formula implies that deposit accumulation rates of millimeters (mm) to greater than 1 cm per hour, which are not uncommon during heavy ash fall, are associated with airborne concentrations of 10²–10³ milligrams per cubic meter (mg/m³). These concentrations are much higher than published measurements (10^-3–10¹ mg/m³), which record only suspended particles sampled in sheltered areas. During heavy ashfall, most fine ash falls as aggregates. Whether such aggregates will be ingested into air ducts will depend on the aggregate size and fall rate, the fragility of the aggregates, the air duct geometry, intake velocity, and other factors.

Released December 22, 2020 08:06 EST

2020, Report

Hannah Brenkert-Smith, Chris Chambers, Katie Gibble, Christopher M. Barth, Colleen Donovan, Carolyn Wagner, Alison Lerch, James R. Meldrum, Patricia A. Champ

Wildfire affects many types of communities. Improved understandings of urban conflagrations are leading some fire-prone communities, such as Ashland, Oregon, to expand their attention from focusing solely on the intermix fringe to managing wildfire threats across more urbanized wildland urban interface (WUI) communities. The core intent of this project was to build a partnership between the Wildfire Research (WiRē) Team and Ashland Fire and Rescue (AFR) by leveraging existing wildfire risk data collected in March 2018 and pairing it with newly collected social data to better understand Ashland, Oregon residents’ knowledge, experiences, and perceptions about wildfire risk. This greater understanding will help AFR focus its programs and outreach and ultimately promote increased mitigation and reduced wildfire risk in Ashland.

Released December 22, 2020 07:35 EST

2021, Book chapter, Renewing our rivers—Stream corridor restoration in dryland regions

Waite Osterkamp, Mark K. Briggs, David Dean, Alfredo Rodriquez

An assessment of a drainage basin and its stream corridor will provide the data and information needed to understand current biophysical conditions and trends. Developing an understanding of the drivers of change is the next essential step for restoration success (Osterkamp and Toy, 1997; Corenbilt et al., 2007; Briggs and Osterkamp, 2003), Shields et al. 2003; Osterkamp et al., 2011). Establishing such a robust scientific foundation will allow stream practitioners to develop realistic restoration objectives and the tactics that will be effective to achieve them. Accomplishing this requires collecting data at watershed and reach scales and by drawing on scientific data from areas where conditions may be similar to, or applicable to, your site. Although decisions should be backed by conclusive data, to make progress we need to rely on the best available information, even if scientific uncertainty remains. Additional information will become available, so it is necessary to plan a project in a manner that incorporates available knowledge and permits goals, objectives, and tactics to be adjusted accordingly.

Released December 22, 2020 07:23 EST

2021, Environmental Pollution (271)

Chris S. Eckley, Todd P. Luxton, Brooks Stanfield, Austin K. Baldwin, JoAnn Holloway, John McKernan, Mark Johnson

Released December 21, 2020 17:13 EST

2020, Fact Sheet 2020-3068

U.S. Geological Survey

Alaska’s landscapes are changing at a more rapid rate than those of the lower 48. Its large size makes the collection of aerial surveys—a biannual occurrence for the conterminous United States—cost-prohibitive. That means the Landsat series of land imaging satellites offer the only publicly available, up-to-date imagery of land conditions for Alaska. Landsat satellites underpin public and private sector decisions in the State and across the Nation for effective adaptation to changing landscapes.

Released December 21, 2020 17:11 EST

2020, Fact Sheet 2020-3066

U.S. Geological Survey

Maine is a place of rocky coastlines, of rich maritime history symbolized by lighthouses dotting the ocean bluffs, and of wondrous nature areas like the granite and spruce islands of Acadia National Park. But Maine is a place of changes, too. Climate variability has brought the state heavier and more frequent rainstorms. Summers are hotter and drier. With sea levels rising, severe storms increasingly cause floods that damage property and infrastructure. In the coming decades, Landsat satellite systems can be valuable tools in monitoring those changes and their effects on the land and in the water.

Released December 21, 2020 17:10 EST

2020, Fact Sheet 2020-3065

U.S. Geological Survey

In Ohio, remote-sensing systems such as Landsat play an important role in monitoring natural resources and informing management decisions on everything from dangerous freshwater algal blooms to gypsy moth defoliation and more. Landsat imagery underpins public and private sector decisions in Ohio and across the Nation for effective adaptation to changing landscapes. Those decisions lead to enhanced agricultural productivity, smart urban development, sustainable forest management, and inland lake water-quality monitoring.

Released December 21, 2020 17:10 EST

2020, Fact Sheet 2020-3060

U.S. Geological Survey

New Mexico relies on observations from the Landsat series of satellites operated by the U.S. Geological Survey. Data from Landsat also assist New Mexico in managing its precious water resources for agriculture, recreation, and industrial and community consumption. Landsat supports a variety of public and private sector decisions across New Mexico and the Nation for effective adaptation to changing landscapes.

Released December 21, 2020 17:10 EST

2020, Fact Sheet 2020-3059

U.S. Geological Survey

Landsat land-imaging satellites underpin public and private sector decisions in the Minnesota and across the Nation for effective adaptation to changing landscapes. Those decisions often lead to enhanced agricultural productivity, smart urban development, and sustainable forest management. Landsat also enables more accurate inland lake water-quality monitoring, increased aster resilience and risk assessment, effective water use, more-informed climate research, and other applications.

Released December 21, 2020 17:09 EST

2020, Fact Sheet 2020-3053

Angela L. Robinson, Vincent E. White

Information concerning the availability, use, and quality of water in Red River Parish, Louisiana, is critical for proper water-supply management. The purpose of this fact sheet is to present information that can be used by water managers, parish residents, and others for stewardship of this vital resource. In 2014, about 5.76 million gallons per day (Mgal/d) of water were withdrawn in Red River Parish: about 4.23 Mgal/d from groundwater sources and 1.54 Mgal/d from surface-water sources. Withdrawals for agricultural use, composed of general irrigation, rice irrigation, and livestock uses, accounted for about 72 percent (4.15 Mgal/d) of the total water withdrawn. Other categories of use included public supply (about 18 percent of the total water withdrawn, or 1.03 Mgal/d), industry (about 7 percent, or 0.39 Mgal/d), and rural domestic (about 4 percent, or 0.20 Mgal/d). Water-use data collected at 5-year intervals from 1960 to 2010 and again in 2014 indicated that water withdrawals peaked in 1975 at more than 7.3 Mgal/d.

Released December 21, 2020 17:08 EST

2020, Fact Sheet 2020-3052

Angela L. Robinson, Vincent E. White

Information concerning the availability, use, and quality of water in Bienville Parish, Louisiana, is critical for proper water-supply management. The purpose of this fact sheet is to present information that can be used by water managers, parish residents, and others for stewardship of this vital resource. In 2014, about 13.03 million gallons per day (Mgal/d) of water were withdrawn in Bienville Parish, including about 12.88 Mgal/d from groundwater sources and 0.15 Mgal/d from surface-water sources. Withdrawals for industrial use accounted for about 78 percent (10.18 Mgal/d) of the total water withdrawn. Other categories of use included public supply, which accounted for about 18 percent of the total water withdrawn (2.33 Mgal/d); agriculture, composed of general irrigation and livestock, which accounted for about 1 percent (0.18 Mgal/d); and rural domestic (0.33 Mgal/d), which accounted for about 2 percent. Water-use data collected at 5-year intervals from 1960 to 2010 and again in 2014 indicated that water withdrawals peaked in 1995 at more than 17 Mgal/d.

Released December 21, 2020 08:28 EST

2020, Scientific Investigations Report 2020-5007

Andre B. Ritchie, Jeff D. Pepin

The U.S. Geological Survey, in cooperation with the Albuquerque Bernalillo County Water Utility Authority (ABCWUA), measures groundwater levels continuously (hourly) and discretely (semiannually and annually) at a network of wells and piezometers (hereafter called the observation network) within the Middle Rio Grande Basin in central New Mexico. Groundwater levels that are measured in this observation network provide a long-term hydrologic dataset that is heavily relied upon to make water management decisions. The desire to upgrade and perform maintenance on this observation network initiated this study, which assesses the spatial and temporal importance of measurements towards optimization of monitoring the observation network to reduce or redirect monitoring costs. This report describes the methods and results of the optimization assessment of this observation network, which included separate spatial and temporal methodologies and an evaluation using principal component analysis (PCA).

Results from the spatial optimization assessment can be used to help identify observation network sites that do not significantly affect the generation of winter groundwater-elevation contour maps of the production zone. Results from the temporal optimization assessment and PCA can also be consulted when deciding which sites to remove from the network, especially for sites that are monitored more frequently than annually. Results from the temporal optimization assessment can be used to inform the minimum monitoring frequency at the observation network required to capture the trends shown in higher frequency monitoring. The PCA results distinguish spatially distributed characteristic water-level trends that can inform the management decisions that are made when using the spatial and temporal optimization assessment results. Reducing the temporal frequency or spatial density of monitoring is ultimately a management decision that depends on the amount of data loss or degradation that is deemed acceptable while still meeting the network objectives of the ABCWUA. This study can also serve as a starting point to a data gap analysis of local aquifer characteristics and help guide enhanced observation network design as needs arise or in advance of future water management decisions.

The results of the spatial optimization assessment indicate that as many as about 20 specified sites can be removed from the observation network with a relatively small loss in the ability to represent the kriged groundwater-elevation surfaces of the production zone that were generated by using median groundwater elevations for two periods: the 2001 time interval and 2015 time interval. This analysis also demonstrated the importance of wells at the margin of the study area and in areas where there are large hydrologic gradients. At many of the 47 hourly monitored sites analyzed in the temporal optimization assessment, temporal trends were well represented for at least one of the reduced monitoring frequencies tested, indicating that a reduced frequency may be sufficient to adequately characterize seasonal and long-term trends. PCA and k-means clustering analysis of the 15 hourly monitored sites that are screened within the production zone indicate that the sites can be categorized into four groups, or clusters, of differing groundwater-level hydrograph characteristics. Except for one cluster, all of the clusters have the potential to be well represented by fewer index monitoring sites.

Released December 21, 2020 05:56 EST

2020, Scientific Investigations Map 3467

Shelby L. Hunter, Adam R. Trevisan, Jennifer Villa, Kevin A. Smith

The U.S. Geological Survey (USGS), in cooperation with the Grand River Dam Authority, completed a high-resolution multibeam bathymetric survey to compute a new area and capacity table for Grand Lake O’ the Cherokees in northeastern Oklahoma. Area and capacity tables identify the relation between the elevation of the water surface and the volume of water that can be impounded at each water-surface elevation. The area and capacity of Grand Lake O’ the Cherokees were computed from a triangular irregular network surface created in Global Mapper Version 21.0.1. The triangular irregular network surface was created from three datasets: (1) a multibeam mapping system bathymetric survey of Grand Lake O’ the Cherokees completed during April–July 2019, (2) a previous bathymetric survey of the Neosho, Spring, and Elk Rivers, and (3) a 2010 USGS lidar-derived digital elevation model. The digital elevation model data were used in areas with land-surface elevations greater than 744 feet above the North American Vertical Datum of 1988 where the multibeam sonar data could not be collected. The 2019 multibeam sonar data were the predominant data used to compute the new area and capacity table for Grand Lake O’ the Cherokees.

Released December 20, 2020 06:41 EST

2020, Ecology of Freshwater Fish

Emily A. Buege, Peter Esselman, Sarah J. Praskievicz

The Cichlidae are among the most diversified families of fish in the Neotropics and represent an important component of aquatic biodiversity. Understanding cichlid nest‐site selection is important for assemblages facing uncertain futures due to species invasions and environmental change. This information could be used to predict how inter‐ and intraspecific competition for reproductive space may affect populations with changing community dynamics or to identify areas as targets for conservation. We investigated which hydrogeomorphological factors correlated to preferred nest sites of four native cichlid species in the Bladen River, Belize. We recorded the locations of nest sites and collected habitat data through the study reach, including flow velocity, depth, sediment type, fish cover type richness and distance to the bank. Nest locations and physical habitat data were used to construct spatially explicit habitat models using boosted regression trees (BRTs). The models provided statistically significant evidence that physical habitat variables influence the distribution of the nest sites. We found that all species except Archocentrus spilurus were associated with substrate, specifically sand. Thorichthys meeki was also associated with lower water velocities, whereas Cichlasoma salvini was influenced by all five variables. Vieja maculicauda and Archocentrus spilurus were both influenced by flow velocity, distance to bank and depth, although A. spilurus preferred deeper, slightly faster locations about the same distance to the bank. This study suggests that the spatial distribution of nest sites within this cichlid community is significantly different than random and is at least partially governed by physical controls.

Released December 20, 2020 06:35 EST

2020, North American Journal of Fisheries Management

David Kazyak, Barbara A. Lubinski, Jacob M Rash, Thomas C Johnson, Timothy L. King

Following centuries of declines, there is growing interest in conserving extant wild populations and reintroducing Brook Trout (Salvelinus fontinalis) populations of native ancestry. A population genetic baseline can enhance conservation outcomes and promote restoration success. Consequently, it is important to document existing patterns of genetic variation across the landscape and translate these data into an approachable format for fisheries managers. We genotyped 9,507 Brook Trout representing 467 wild collections at 12 microsatellite loci to establish a genetic baseline for North Carolina, USA. Rarefied allelic richness and observed heterozygosity, which reflect within‐population diversity, were low to moderate relative to levels typically observed at higher latitudes (means = 3.12 and 0.42, respectively). Effective population sizes varied widely, but were often very low (151 collections with an estimated N_e < 10). Despite decades of intensive stocking across the state, we found little to no evidence of hatchery introgression in most populations. Although genetic variation was significant at a variety of spatial scales (mean pairwise F’_ST = 0.73), substantial genetic variation occurred between patches within individual watersheds. Analysis of molecular variance (AMOVA) found that a substantial portion (28.5%) of the observed genetic variation was attributed to differences among populations, with additional genetic variation among hydrological units (HUCs; 16.0%, 16.6%, 12.1%, and 9.4% of the overall variation among twelve‐, ten‐, eight‐, and six‐digit HUCs, respectively). We discuss a suite of potential applications for this type of genetic data to enhance management outcomes, such as conservation prioritization and selection of source stocks for reintroductions or genetic rescue.