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At least 865 records · Page 48Linked to original sources
USGS2010

Conceptual ecological models to guide integrated landscape monitoring of the Great Basin

The Great Basin Integrated Landscape Monitoring Pilot Project was developed in response to the need for a monitoring and predictive capability that addresses changes in broad landscapes and waterscapes. Human communities and needs are nested within landscapes formed by interactions among the hydrosphere, geosphere, and biosphere. Understanding the complex processes that shape landscapes and deriving ways to manage them sustainably while meeting human needs require sophisticated modeling and monitoring. This document summarizes current understanding of ecosystem structure and function for many of the ecosystems within the Great Basin using conceptual models. The conceptual ecosystem models identify key ecological components and processes, identify external drivers, develop a hierarchical set of models that address both site and landscape attributes, inform regional monitoring strategy, and identify critical gaps in our knowledge of ecosystem function. The report also illustrates an approach for temporal and spatial scaling from site-specific models to landscape models and for understanding cumulative effects. Eventually, conceptual models can provide a structure for designing monitoring programs, interpreting monitoring and other data, and assessing the accuracy of our understanding of ecosystem functions and processes.

Scientific Investigations Report↗
USGS2006

Two-dimensional magnetotelluric model of deep resistivity structure in the Bodie-Aurora district of California

Introduction: Magnetotelluric data were acquired during October 2001 by the U.S. Geological Survey (USGS) as part of a study to examine the structural nature of basins in the transition zone between the Sierra Nevada Mountains of California and the Basin and Range province of Nevada. Magnetotelluric (MT) geophysical studies assist the mapping of geologic structure and the inference of lithologic packages that are concealed beneath the Earth's surface. The Basin and Range province has a complicated geologic history, which includes extension and compression of the Earth's crust to form the basins and ranges that blanket much of Nevada. The basins and ranges in the vicinity of this study trend northeastward and are bounded by steeply dipping strike slip faults. Interestingly, deep east-west magnetic trends occur in the aeromagnetic data of this study area indicating that the northeast-trending basins and ranges represent only thin-skinned deformation at the surface with an underlying east-west structure. To investigate this issue, MT data were acquired at seven stations in eastern California, 20 km east of Mono Lake. The purpose of this report is to present a two-dimensional apparent resistivity model of the MT data acquired for this study.

Open-File Report↗
USGS2015

A framework for modeling anthropogenic impacts on waterbird habitats: addressing future uncertainty in conservation planning

The amount and quality of natural resources available for terrestrial and aquatic wildlife habitats are expected to decrease throughout the world in areas that are intensively managed for urban and agricultural uses. Changes in climate and management of increasingly limited water supplies may further impact water resources essential for sustaining habitats. In this report, we document adapting a Water Evaluation and Planning (WEAP) system model for the Central Valley of California. We demonstrate using this adapted model (WEAP-CV wh ) to evaluate impacts produced from plausible future scenarios on agricultural and wetland habitats used by waterbirds and other wildlife. Processed output from WEAP-CV wh indicated varying levels of impact caused by projected climate, urbanization, and water supply management in scenarios used to exemplify this approach. Among scenarios, the NCAR-CCSM3 A2 climate projection had a greater impact than the CNRM-CM3 B1 climate projection, whereas expansive urbanization had a greater impact than strategic urbanization, on annual availability of waterbird habitat. Scenarios including extensive rice-idling or substantial instream flow requirements on important water supply sources produced large impacts on annual availability of waterbird habitat. In the year corresponding with the greatest habitat reduction for each scenario, the scenario including instream flow requirements resulted in the greatest decrease in habitats throughout all months of the wintering period relative to other scenarios. This approach provides a new and useful tool for habitat conservation planning in the Central Valley and a model to guide similar research investigations aiming to inform conservation, management, and restoration of important wildlife habitats.

California↗
USGS2010

Simulation of the shallow groundwater-flow system near the Hayward Airport, Sawyer County, Wisconsin

There are concerns that removal and trimming of vegetation during expansion of the Hayward Airport in Sawyer County, Wisconsin, could appreciably change the character of a nearby cold-water stream and its adjacent environs. In cooperation with the Wisconsin Department of Transportation, a two-dimensional, steady-state groundwater-flow model of the shallow groundwater-flow system near the Hayward Airport was refined from a regional model of the area. The parameter-estimation code PEST was used to obtain a best fit of the model to additional field data collected in February 2007 as part of this study. The additional data were collected during an extended period of low runoff and consisted of water levels and streamflows near the Hayward Airport. Refinements to the regional model included one additional hydraulic-conductivity zone for the airport area, and three additional parameters for streambed resistance in a northern tributary to the Namekagon River and in the main stem of the Namekagon River. In the refined Hayward Airport area model, the calibrated hydraulic conductivity was 11.2 feet per day, which is within the 58.2 to 7.9 feet per day range reported for the regional glacial and sandstone aquifer, and is consistent with a silty soil texture for the area. The calibrated refined model had a best fit of 8.6 days for the streambed resistance of the Namekagon River and between 0.6 and 1.6 days for the northern tributary stream. The previously reported regional groundwater-recharge rate of 10.1 inches per year was adjusted during calibration of the refined model in order to match streamflows measured during the period of extended low runoff; this resulted in an optimal groundwater-recharge rate of 7.1 inches per year during this period. The refined model was then used to simulate the capture zone of the northern tributary to the Namekagon River.

Scientific Investigations Report↗
USGS2003

A compendium of P- and S-wave velocities from surface-to-borehole logging; summary and reanalysis of previously published data and analysis of unpublished data

For over 28 years, the U.S. Geological Survey (USGS) has been acquiring seismic velocity and geologic data at a number of locations in California, many of which were chosen because strong ground motions from earthquakes were recorded at the sites. The method for all measurements involves picking first arrivals of P- and S-waves from a surface source recorded at various depths in a borehole (as opposed to noninvasive methods, such as the SASW method [e.g., Brown et al., 2002]). The results from most of the sites are contained in a series of U.S. Geological Survey Open-File Reports (see References). Until now, none of the results have been available as computer files, and before 1992 the interpretation of the arrival times was in terms of piecemeal interval velocities, with no attempt to derive a layered model that would fit the travel times in an overall sense (the one exception is Porcella, 1984). In this report I reanalyze all of the arrival times in terms of layered models for P- and for S-wave velocities at each site, and I provide the results as computer files. In addition to the measurements reported in the open-file reports, I also include some borehole results from other reports, as well as some results never before published. I include data for 277 boreholes (at the time of this writing; more will be added to the web site as they are obtained), all in California (I have data from boreholes in Washington and Utah, but these will be published separately). I am also in the process of interpreting travel time data obtained using a seismic cone penetrometer at hundreds of sites; these data can be interpreted in the same way of those obtained from surface-to-borehole logging. When available, the data will be added to the web site (see below for information on obtaining data from the World Wide Web (WWW)). In addition to the basic borehole data and results, I provide information concerning strong-motion stations that I judge to be close enough to the boreholes that the borehole velocity models can be used as the velocity models beneath the stations.

California↗
USGS2025

Impact of thermoelectric power plant operations and water use reporting methods on thermoelectric power plant water use

Thermoelectric power generation accounts for over 41% of total U.S. freshwater withdrawals, making understanding the determinants of power plants’ water withdrawals (WW) and consumption (WC) critical for reducing the sector’s reliance on increasingly scarce water resources. However, reported data inconsistencies and incomplete analysis of potential determinants of thermoelectric water use hinder such understanding. We address these challenges by introducing a novel data filtering method and a more complete assessment of water use determinants. First, we applied a power-cooling ratio as an operations-based data filter that removed operationally implausible records while retaining more original data, outperforming previous statistical filtering methods. Second, we found that different water use reporting methods (WURMs) provided statistically significantly different WW and WC values, revealing the importance of this previously unrecognized feature in reported water use records. Third, our data-driven approach showed that traditionally emphasized features─such as cooling technology and gross generation─are of primary importance but can be surpassed by other, often overlooked, features when modeling WW or WC individually. The plant configuration, cooling technology, and gross generation were the most important features of WW, whereas WURM, cooling technology, and reporting month were the most important for WC. These findings can improve thermoelectric power plant management, water use reporting accuracy, and water use modeling.

Environmental Science & Technology↗
USGS2025

The importance of sampling design for unbiased estimation of survival using joint live-recapture and live resight models

Survival is a key life history parameter that can inform management decisions and basic life history research. Because true survival is often confounded with emigration from the study area, many studies are forced to estimate apparent survival (i.e., probability of surviving and remaining inside the study area), which can be much lower than true survival for highly mobile species. One method for estimating true survival is the Barker joint live-recapture/live-resight (JLRLR) model, which combines capture data from a study area (hereafter the ‘capture site’) with resighting data from a broader geographic area. This model assumes that live resights occur throughout the entire area where animals can disperse to and this assumption is often not met in practice. Here we use simulation to evaluate survival bias from a JLRLR model under study design scenarios that differ in the site selection for resights: global, random, fixed including the capture site, and fixed excluding the capture site. Simulation results indicate that fixed designs that included the capture site showed negative survival bias, whereas fixed designs that excluded the capture site exhibited positive survival bias. The magnitude of the bias was dependent on movement and survival, where scenarios with high survival and frequent movement had minimal bias. In an effort to help minimize bias, we developed a multistate version of the JLRLR and demonstrated reductions in survival bias compared to the single-state version for most designs. Our results suggest minimizing bias can be accomplished by: 1) using a random resight design when feasible if global sampling is not possible, 2) using the multistate JLRLR model when appropriate, 3) including the capture site in the resight sampling frame when possible, and 4) reporting survival as apparent survival if fixed sites are used for resight with the single state JLRLR model.

Peer Community Journal↗
USGS2013

Application of a hydrodynamic and sediment transport model for guidance of response efforts related to the Deepwater Horizon oil spill in the Northern Gulf of Mexico along the coast of Alabama and Florida

U.S. Geological Survey (USGS) scientists have provided a model-based assessment of transport and deposition of residual Deepwater Horizon oil along the shoreline within the northern Gulf of Mexico in the form of mixtures of sand and weathered oil, known as surface residual balls (SRBs). The results of this USGS research, in combination with results from other components of the overall study, will inform operational decisionmaking. The results will provide guidance for response activities and data collection needs during future oil spills. In May 2012 the U.S. Coast Guard, acting as the Deepwater Horizon Federal on-scene coordinator, chartered an operational science advisory team to provide a science-based review of data collected and to conduct additional directed studies and sampling. The goal was to characterize typical shoreline profiles and morphology in the northern Gulf of Mexico to identify likely sources of residual oil and to evaluate mechanisms whereby reoiling phenomena may be occurring (for example, burial and exhumation and alongshore transport). A steering committee cochaired by British Petroleum Corporation (BP) and the National Oceanic and Atmospheric Administration (NOAA) is overseeing the project and includes State on-scene coordinators from four States (Alabama, Florida, Louisiana, and Mississippi), trustees of the U.S. Department of the Interior (DOI), and representatives from the U.S. Coast Guard. This report presents the results of hydrodynamic and sediment transport models and developed techniques for analyzing potential SRB movement and burial and exhumation along the coastline of Alabama and Florida. Results from these modeling efforts are being used to explain the complexity of reoiling in the nearshore environment and to broaden consideration of the different scenarios and difficulties that are being faced in identifying and removing residual oil. For instance, modeling results suggest that larger SRBs are not, under the most commonly observed low-energy wave conditions, likely to move very far alongshore. This finding suggests that SRBs from one source location may not (outside of storm conditions) be redistributed to other up or down coast locations. This information can guide operational response decisions. In addition, because SRBs are less mobile compared with sand, they are likely to become buried and unburied under normal sand transport processes thereby lengthening the time SRBs may take to move onshore. The rate of onshore movement was not specifically addressed by this study, yet the results resolve the cross-shore domain and cross-shore variations in alongshore transport that are relevant to achieving the primary objectives. Furthermore, during infrequent events (for example, winter storms and severe meteorological events such as Hurricane Isaac of August 2012), energy is shown to be sufficient to move a greater range of SRB sizes and potentially expose and break up submerged oil mats. When SRBs do move alongshore, the models indicate that there are regions that are more conducive to accumulation of SRB material than others. Accumulation can occur where there are reversals and decelerations in alongshore currents and where forces created by shear stress drops below critical thresholds to maintain or initiate SRB movement. In addition, flow and SRB mobility patterns around inlets indicate patterns in hydrodynamic forces that influence redistribution of SRBs and the surface oil that mixed with sediment to form oil mats in the first place.

Alabama;Florida↗
USGS2025

Review of the Lake Washington Ship Canal and Ballard Locks model, Seattle, Washington, 2014–20

Executive Summary The Hiram M. Chittenden (Ballard) Locks and Lake Washington Ship Canal connect freshwater Lake Washington and saline Shilshole Bay of Puget Sound in Seattle, Washington. The locks and canal allow for ships to traverse this reach. Anadromous salmonids also migrate through, transitioning between saline and freshwater environments, and making use of a fish ladder at the locks when traveling upstream. WEST Consultants, Inc., constructed a two-dimensional hydrodynamic and water-quality model (CE-QUAL-W2) simulating flow, water temperature, and salinity for the Ballard Locks and the Lake Washington Ship Canal. An initial model was built for calendar years 2014–15, and the model was updated using a more recent and modern dataset for calendar years 2016–20. The U.S. Army Corps of Engineers requested that the U.S. Geological Survey review this model and its documentation to evaluate the technical aspects of its development and calibration. Findings from this review include the following: Overall, the Lake Washington Ship Canal CE-QUAL-W2 model was well-documented and constructed largely following typical model-development methods. The Lake Washington Ship Canal model was built with CE-QUAL-W2 model version 4.5, compiled and released by Portland State University in April 2021. CE-QUAL-W2 updates and improvements are regularly released with bug fixes and new features, so any model updates would benefit from the use of the most-recent software release. The model grid that represents the Lake Washington Ship Canal bathymetry was 9.2 kilometers (5.7 miles) long, matching the expected length of the waterway. The deepest model segments were near sampling site LLLW (Large Locks site) near the locks. Lake Union is reported to constitute most of the volume of the Lake Washington Ship Canal and is depicted as such in the model grid. The model includes several water outflows at Ballard Locks, including the large and small locks, a saltwater drain, a spillway, smolt flumes, and a fish ladder. Flows from the spillway, smolt flumes, and fish ladder were combined into one structure outflow in the model and assigned one withdrawal elevation from the Lake Washington Ship Canal. The smolt flume and spillway withdraw from the same elevation, but the fish ladder flow withdraws from a higher elevation in Lake Washington Ship Canal, and that flow could be separated into its own withdrawal. The model input files were created using the Coordinated Universal Time standard instead of the more typical choice of using local standard time. This is not incorrect, but sub-daily results would need to be converted to local time for science-communication purposes. The meteorological dataset had some unexpected anomalies, such as a baseline shift in the wind-speed dataset. Other nearby meteorological datasets could be used instead or used to correct the current meteorological inputs. The upstream boundary was configured with water-temperature data from a continuous monitor buoy in Lake Washington. The boundary salinity was set at 0 parts per thousand for the duration of the model simulation. A more realistic estimate of salinity at the upstream boundary could be constructed using data from the same buoy. Saline inflow at the downstream boundary of the Lake Washington Ship Canal model through lock exchanges at the large lock was included as a tributary in the model. Salinity and temperature inputs in this tributary at the large locks were set as constant values for the entire simulation. Saline inflow through the small lock was not included in the model because few data were available, and the input was likely to be small because of the smaller surface area and volume of the small lock relative to the large lock. The model did not include any flow, water temperature, or salinity inputs to the Lake Washington Ship Canal other than at the locks and at the upstream boundary. Any point sources, small tributaries, or stormwater inputs were omitted from the model. It is unclear whether this is a substantial omission relative to model results. Most model parameters were set as defaults or to reasonable values. However, the value of the WINDH parameter, the height of the wind speed measurement, was different than the height of the meteorological site. Compared to measured data, the model simulated water-surface elevations and water temperatures with reasonable accuracy. Differences in the modeled and measured salinities revealed some opportunities to improve the simulation of salinity, both baseline salinity and the salinity maxima in summer and autumn.

Washington↗
USGS2003

Preliminary northeast Asia geodynamics map

This map portrays the geodynamics of Northeast Asia at a scale of 1:5,000,000 using the concepts of plate tectonics and analysis of terranes and overlap assemblages. The map is the result of a detailed compilation and synthesis at 5 million scale and is part of a major international collaborative study of the Mineral Resources, Metallogenesis, and Tectonics of Northeast Asia conducted from 1997 through 2002 by geologists from earth science agencies and universities in Russia, Mongolia, Northeastern China, South Korea, Japan, and the USA. This map is the result of extensive geologic mapping and associated tectonic studies in Northeast Asia in the last few decades and is the first collaborative compilation of the geology of the region at a scale of 1:5,000,000 by geologists from Russia, Mongolia, Northeastern China, South Korea, Japan, and the USA. The map was compiled by a large group of international geologists using the below concepts and definitions during collaborative workshops over a six-year period. The map is a major new compilation and re-interpretation of pre-existing geologic maps of the region. The map is designed to be used for several purposes, including regional tectonic analyses, mineral resource and metallogenic analysis, petroleum resource analysis, neotectonic analysis, and analysis of seismic hazards and volcanic hazards. The map consists of two sheets. Sheet 1 displays the map at a scale of 1:5,000,000, explanation. Sheet 2 displays the introduction, list of map units, and source references. Detailed descriptions of map units and stratigraphic columns are being published separately. This map is one of a series of publications on the mineral resources, metallogenesis, and geodynamics,of Northeast Asia. Companion studies and other articles and maps , and various detailed reports are: (1) a compilation of major mineral deposit models (Rodionov and Nokleberg, 2000; Rodionov and others, 2000; Obolenskiy and others, in press a); (2) a series of metallogenic belt maps (Obolenskiy and others, 2001; in press b); (3) a lode mineral deposits and placer districts location map for Northeast Asia (Ariunbileg and others, in press b); (4) descriptions of metallogenic belts (Rodionov and others, in press); and (5) a database on significant metalliferous and selected nonmetalliferous lode deposits, and selected placer districts (Ariunbileg and others, in press a).

Open-File Report↗
USGS2015

Elk monitoring in Mount Rainier and Olympic national parks: 2008-2011 synthesis report

In 2008, the USGS collaborated with the NPS, the Muckleshoot and Puyallup Indian Tribes, and WDFW to develop a protocol tor monitor changes in abundance, population composition, and spatial distribution of elk on summer ranges in MORA and OLYM and winter ranges in OLYM. We developed double-observer sightability (DO-S) models that adjusted raw counts of elk as a function of factors influencing detection probabilities from the air, e.g. vegetation, elk group size, light, elk activity, and pilot experience. We plan to develop DO-S models for both MORA and OLYM summer ranges, but due to radiotelemetry collar failures in OLYM, we do not yet have enough data to model detection probabilities in OLYM. We analyzed results of the first 4 years of elk monitoring conducted under the new protocol from 2008-2011. Objectives of this first synthetic analysis are to: • update the DO-S model for MORA aerial survey results • examine abundance, composition, and distribution of elk trends in MORA summer ranges • establish a baseline of counts, population composition, and distribution of elk in OLYM summer ranges • examine trends in counts and distribution of elk in OLYM low-elevation winter ranges during early spring • determine environmental factors influencing abundance and composition of elk in selected MORA summer ranges and unadjusted counts of elk on selected OLYM winter ranges • review progress in developing a DO-S model for OLYM elk surveys • examine aerial survey operations and provide suggestions for future surveys. There was no trend in elk numbers in the N. Rainier TCA from 2008-2011; the trend in the S. Rainier TCA was not statistically significant but increased 3.3%/year. Maximum counts increased in the N. Rainier TCA ~6%/year. Maximum counts in the S. Rainier TCA increased at a rate of 17% annually. Due to failed radiocollars, weather, and other problems, we completed surveys in 2 of 5 OLYM summer range TCAs; no trend data are available. In OLYM winter ranges, we surveyed the Hoh TCA during early spring 2008-10 and of the S. Fork Hoh and Queets in 2008 and 2010. No surveys were done for early-spring counts in 2011 and 2012 due to high snowfall and lack of funding. Legacy early-spring surveys in OLYM since 1985 allowed us to assess trends in counts in the early-spring TCAs from 1985-2010. Counts of elk in the early-spring TCAs declined: 63% in the S. Fork Hoh, 18% in the Hoh, and 22% in the Queets Valley. We continue to develop and improve the DO-S model for application to OLYM summer surveys. In the next synthesis report, we will update findings with additional data following the 2015 field season, based on 8 years of survey results; it will be a more complete analysis of elk population trends.

Washington↗
USGS2005

Evaluation of models and data for assessing whooping crane habitat in the central Platte River, Nebraska

The primary objectives of this evaluation were to improve the performance of the Whooping Crane Habitat Suitability model (C4R) used by the U.S. Fish and Wildlife Service (Service) for defining the relationship between river discharge and habitat availability, and to assist the Service in implementing improved model(s) with existing hydraulic files. The C4R habitat model is applied at the scale of individual river cross-sections, but the model outputs are scaledup to larger reaches of the river using a decision support “model” comprised of other data and procedures. Hence, the validity of the habitat model depends at least partially on how its outputs are incorporated into this larger context. For that reason, we also evaluated other procedures including the PHABSIM data files, the FORTRAN computer programs used to implement the model, and other parameters used to simulate the relationship between river flows and the availability of Whooping Crane roosting habitat along more than 100 miles of heterogeneous river channels. An equally important objective of this report was to fully document these related procedures as well as the model and evaluation results so that interested parties could readily understand the technical basis for the Service’s recommendations.

Nebraska↗
USGS2017

Development of simulated groundwater-contributing areas to selected streams, ponds, coastal water bodies, and production wells in the Plymouth-Carver region and Cape Cod, Massachusetts

Introduction The U.S. Geological Survey (USGS), in support of the Massachusetts Estuaries Project (MEP), delineated groundwater-contributing areas to various hydrologic receptors including ponds, streams, and coastal water bodies throughout southeastern Massachusetts, including portions of the Plymouth-Carver aquifer system and all of Cape Cod. These contributing areas were delineated over a 6-year period from 2003 through 2008 by using previously published regional USGS groundwater-flow models for the Plymouth-Carver region (Masterson and others, 2009), the Sagamore (western) and Monomoy (eastern) flow lenses of Cape Cod (Walter and Whealan, 2005), and lower Cape Cod (Masterson, 2004). The original USGS groundwater-contributing areas were subsequently revised in some locations by the MEP to remove modeling artifacts or to make the contributing areas more consistent with site-specific hydrologic conditions without further USGS review. This report describes the process used to create the USGS groundwater-contributing areas and provides these model results in their original format in a single, publicly accessible publication.

Massachusetts↗
USGS2010

Implementation of the Next Generation Attenuation (NGA) ground-motion prediction equations in Fortran and R

This report presents two methods for implementing the earthquake ground-motion prediction equations released in 2008 as part of the Next Generation Attenuation of Ground Motions (NGA-West, or NGA) project coordinated by the Pacific Earthquake Engineering Research Center (PEER). These models were developed for predicting ground-motion parameters for shallow crustal earthquakes in active tectonic regions (such as California). Of the five ground-motion prediction equations (GMPEs) developed during the NGA project, four models are implemented: the GMPEs of Abrahamson and Silva (2008), Boore and Atkinson (2008), Campbell and Bozorgnia (2008), and Chiou and Youngs (2008a); these models are abbreviated as AS08, BA08, CB08, and CY08, respectively. Since site response is widely recognized as an important influence of ground motions, engineering applications typically require that such effects be modeled. The model of Idriss (2008) is not implemented in our programs because it does not explicitly include site response, whereas the other four models include site response and use the same variable to describe the site condition (VS30). We do not intend to discourage the use of the Idriss (2008) model, but we have chosen to implement the other four NGA models in our programs for those users who require ground-motion estimates for various site conditions. We have implemented the NGA models by using two separate programming languages: Fortran and R (R Development Core Team, 2010). Fortran, a compiled programming language, has been used in the scientific community for decades. R is an object-oriented language and environment for statistical computing that is gaining popularity in the statistical and scientific community. Derived from the S language and environment developed at Bell Laboratories, R is an open-source language that is freely available at http://www.r-project.org/ (last accessed 11 January 2011). In R, the functions for computing the NGA equations can be loaded as an add-on user-contributed code, which is referred to as a ?package? in R. The details of the nga package (Kaklamanos and Thompson, 2010) are presented in this report. In addition, differences between the R and Fortran implementations will be discussed later in this report. The NGA models have established a new baseline for seismic hazard assessments, and they have been incorporated into the most recent national seismic hazard maps published by the U.S. Geological Survey (Petersen and others, 2008). However, many of the new models are significantly more complicated than previous GMPEs and, therefore, require a substantial investment of time to implement and validate. We hope that the scientific and engineering communities find our implementations to be useful in research and practice. Our implementations may be considered as an alternate to the Microsoft Excel spreadsheet implementation available on the PEER NGA project Web site (http://peer.berkeley.edu/ngawest/, last accessed 11 January 2011). The implementations in Fortran and R are more appropriate for performing batch calculations than the implementation in Microsoft Excel. Spreadsheets and Fortran code for some of the individual models also are available on the PEER NGA project Web site; our programs implement the four GMPEs simultaneously. Our programs give the same results as the programs on the PEER NGA Web site, but we offer some additional flexibility of input, additional methods of estimating unknown input parameters, and additional options for output. Although these programs have been used by the U.S. Geological Survey (USGS), Tufts University, and others, no warranty, expressed or implied, is made by Tufts or the USGS as to the accuracy or functioning of the programs and related material, nor shall the fact of distribution constitute any such warranty, and no responsibility is assumed by Tufts or the USGS in connection therewith.

Open-File Report↗
USGS2008

A regression model for computing index flows describing the median flow for the summer month of lowest flow in Michigan

In 2006, Michigan enacted laws to prevent new large capacity withdrawals from decreasing flows to the extent that they would functionally impair a stream's ability to support characteristic fish populations. The median streamflow for the summer month of lowest flow was specified by state decision makers as the index flow on which likely impacts of withdrawals would be assessed. At sites near long-term streamflow-gaging stations, analysis of streamflow records during July, August, and September was used to determine the index flow. At ungaged sites, an alternate method for computing the index flow was needed. This report documents the development of a method for computing index flows at ungaged stream sites in Michigan. The method is based on a regression model that computes the index water yield, which is the index flow divided by the drainage area. To develop the regression model, index flows were determined on the basis of daily flows measured during July, August, and September at 147 streamflow-gaging stations having 10 or more years of record (considered long-term stations) in Michigan. The corresponding index water yields were statistically related to climatic and basin characteristics upstream from the stations in the regression model. Climatic and basin characteristics selected as explanatory variables in the regression model include two aquifer-transmissivity and hydrologic-soil groups, forest land cover, and normal annual precipitation. Regression model estimates of water yield explain about 70.8 percent of the variability in index water yields indicated by streamflow-gaging station records. Index flows computed on the basis of regression-model estimates of water yield and corresponding drainage areas explain about 94.0 percent of the variability in index flows indicated by streamflow-gaging station records. No regional bias was detected in the regression-based estimates of water yield within seven hydrologic subregions spanning Michigan. Thus, the single regression model developed in this report can be used to produce unbiased estimates of index water yield and flow statewide. In addition, a technique is presented for computing prediction intervals about the index flow estimates.

Michigan↗
USGS2006

Simulated water budgets and ground-water/surface-water interactions in Bushkill and parts of Monocacy Creek watersheds, Northampton County, Pennsylvania: A preliminary study with identification of data needs

This report, prepared in cooperation with the Department of Environmental Protection, Office of Mineral Resources Management, provides a preliminary analysis of water budgets and generalized ground-water/surface-water interactions for Bushkill and parts of Monocacy Creek watersheds in Northampton County, Pa., by use of a ground-water flow model. Bushkill Creek watershed was selected for study because it has areas of rapid growth, ground-water withdrawals from a quarry, and proposed stream-channel modifications, all of which have the potential for altering ground-water budgets and the interaction between ground water and streams. Preliminary 2-dimensional, steady-state simulations of ground-water flow by the use of MODFLOW are presented to show the status of work through September 2005 and help guide ongoing data collection in Bushkill Creek watershed. Simulations were conducted for (1) predevelopment conditions, (2) a water table lowered for quarry operations, and (3) anthropogenic changes in hydraulic conductivity of the streambed and aquifer. Preliminary results indicated under predevelopment conditions, the divide between the Bushkill and Monocacy Creek ground-water basins may not have been coincident with the topographic divide and as much as 14 percent of the ground-water discharge to Bushkill Creek may have originated from recharge in the Monocacy Creek watershed. For simulated predevelopment conditions, Schoeneck Creek and parts of Monocacy Creek were dry, but Bushkill Creek was gaining throughout all reaches. Simulated lowering of the deepest quarry sump to an altitude of 147 feet for quarry operations caused ground-water recharge and streamflow leakage to be diverted to the quarry throughout about 14 square miles and caused reaches of Bushkill and Little Bushkill Creeks to change from gaining to losing streams. Lowering the deepest quarry sump to an altitude of 100 feet caused simulated ground-water discharge to the quarry to increase about 4 cubic feet per second. Raising the deepest sump to an altitude of 200 feet caused the simulated discharge to the quarry to decrease about 14 cubic feet per second.Decreasing the hydraulic conductivity of the streambed of Bushkill Creek in the reach of large losses of flow caused simulated ground-water levels to decline and ground-water discharge to a quarry to decrease from 74 to 45 cubic feet per second. Decreasing the hydraulic conductivity of a hypothesized highly transmissive zone with a plug of relatively impermeable material caused ground-water levels to increase east of the plug and decline west of the plug, and decreased the discharge to a quarry from 74 to 53 cubic feet per second. Preliminary results of the study have significant limitations, which need to be recognized by the user. The results demonstrated the usefulness of ground-water modeling with available data sets, but as more data become available through field studies, a more complete evaluation could be conducted of the preliminary assumptions in the conceptual model, model sensitivity, and effects of boundary conditions. Additional streamflow and ground-water-level measurements would be needed to better quantify recharge and aquifer properties, particularly the anisotropy of carbonate rocks. Measurements of streamflow losses at average, steady-state hydrologic conditions could provide a more accurate estimate of ground-water recharge from this source, which directly affects water budgets and contributing areas simulated by the model.

Pennsylvania↗
USGS2015

Incorporating induced seismicity in the 2014 United States National Seismic Hazard Model: results of the 2014 workshop and sensitivity studies

The U.S. Geological Survey National Seismic Hazard Model for the conterminous United States was updated in 2014 to account for new methods, input models, and data necessary for assessing the seismic ground shaking hazard from natural (tectonic) earthquakes. The U.S. Geological Survey National Seismic Hazard Model project uses probabilistic seismic hazard analysis to quantify the rate of exceedance for earthquake ground shaking (ground motion). For the 2014 National Seismic Hazard Model assessment, the seismic hazard from potentially induced earthquakes was intentionally not considered because we had not determined how to properly treat these earthquakes for the seismic hazard analysis. The phrases “potentially induced” and “induced” are used interchangeably in this report, however it is acknowledged that this classification is based on circumstantial evidence and scientific judgment. For the 2014 National Seismic Hazard Model update, the potentially induced earthquakes were removed from the NSHM’s earthquake catalog, and the documentation states that we would consider alternative models for including induced seismicity in a future version of the National Seismic Hazard Model. As part of the process of incorporating induced seismicity into the seismic hazard model, we evaluate the sensitivity of the seismic hazard from induced seismicity to five parts of the hazard model: (1) the earthquake catalog, (2) earthquake rates, (3) earthquake locations, (4) earthquake Mmax (maximum magnitude), and (5) earthquake ground motions. We describe alternative input models for each of the five parts that represent differences in scientific opinions on induced seismicity characteristics. In this report, however, we do not weight these input models to come up with a preferred final model. Instead, we present a sensitivity study showing uniform seismic hazard maps obtained by applying the alternative input models for induced seismicity. The final model will be released after further consideration of the reliability and scientific acceptability of each alternative input model. Forecasting the seismic hazard from induced earthquakes is fundamentally different from forecasting the seismic hazard for natural, tectonic earthquakes. This is because the spatio-temporal patterns of induced earthquakes are reliant on economic forces and public policy decisions regarding extraction and injection of fluids. As such, the rates of induced earthquakes are inherently variable and nonstationary. Therefore, we only make maps based on an annual rate of exceedance rather than the 50-year rates calculated for previous U.S. Geological Survey hazard maps.

Open-File Report↗
USGS1979

Modeling sandhill crane population dynamics

The impact of sport hunting on the Central Flyway population of sandhill cranes (Grus canadensis) has been a subject of controversy for several years. A recent study (Buller 1979) presented new and important information on sandhill crane population dynamics. The present report is intended to incorporate that and other information into a mathematical model for the purpose of assessing the long-range impact of hunting on the population of sandhill cranes.The model is a simple deterministic system that embodies density-dependent rates of survival and recruitment. The model employs four kinds of data: (1) spring population size of sandhill cranes, estimated from aerial surveys to be between 250,000 and 400,000 birds; (2) age composition in fall, estimated for 1974-76 to be 11.3% young; (3) annual harvest of cranes, estimated from a variety of sources to be about 5 to 7% of the spring population; and (4) age composition of harvested cranes, which was difficult to estimate but suggests that immatures were 2 to 4 times as vulnerable to hunting as adults.Because the true nature of sandhill crane population dynamics remains so poorly understood, it was necessary to try numerous (768 in all) combinations of survival and recruitment functions, and focus on the relatively few (37) that yielded population sizes and age structures comparable to those extant in the real population. Hunting was then applied to those simulated populations. In all combinations, hunting resulted in a lower asymptotic crane population, the decline ranging from 5 to 54%. The median decline was 22%, which suggests that a hunted sandhill crane population might be about three-fourths as large as it would be if left unhunted. Results apply to the aggregate of the three subspecies in the Central Flyway; individual subspecies or populations could be affected to a greater or lesser degree.

Special Scientific Report - Wildlife↗