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USGS2015

Observations of territorial breeding common ravens caching eggs of greater sage-grouse

Previous investigations using continuous video monitoring of greater sage-grouse Centrocercus urophasianus nests have unambiguously identified common ravens Corvus corax as an important egg predator within the western United States. The quantity of greater sage-grouse eggs an individual common raven consumes during the nesting period and the extent to which common ravens actively hunt greater sage-grouse nests are largely unknown. However, some evidence suggests that territorial breeding common ravens, rather than nonbreeding transients, are most likely responsible for nest depredations. We describe greater sage-grouse egg depredation observations obtained opportunistically from three common raven nests located in Idaho and Nevada where depredated greater sage-grouse eggs were found at or in the immediate vicinity of the nest site, including the caching of eggs in nearby rock crevices. We opportunistically monitored these nests by counting and removing depredated eggs and shell fragments from the nest sites during each visit to determine the extent to which the common raven pairs preyed on greater sage-grouse eggs. To our knowledge, our observations represent the first evidence that breeding, territorial pairs of common ravens cache greater sage-grouse eggs and are capable of depredating multiple greater sage-grouse nests.

Idaho, Nevada↗

USGS2010

Hazards affecting grizzly bear survival in the Greater Yellowstone Ecosystem

During the past 2 decades, the grizzly bear ( Ursus arctos ) population in the Greater Yellowstone Ecosystem (GYE) has increased in numbers and expanded its range. Early efforts to model grizzly bear mortality were principally focused within the United States Fish and Wildlife Service Grizzly Bear Recovery Zone, which currently represents only about 61% of known bear distribution in the GYE. A more recent analysis that explored one spatial covariate that encompassed the entire GYE suggested that grizzly bear survival was highest in Yellowstone National Park, followed by areas in the grizzly bear Recovery Zone outside the park, and lowest outside the Recovery Zone. Although management differences within these areas partially explained differences in grizzly bear survival, these simple spatial covariates did not capture site-specific reasons why bears die at higher rates outside the Recovery Zone. Here, we model annual survival of grizzly bears in the GYE to 1) identify landscape features (i.e., foods, land management policies, or human disturbances factors) that best describe spatial heterogeneity among bear mortalities, 2) spatially depict the differences in grizzly bear survival across the GYE, and 3) demonstrate how our spatially explicit model of survival can be linked with demographic parameters to identify source and sink habitats. We used recent data from radiomarked bears to estimate survival (1983–2003) using the known-fate data type in Program MARK. Our top models suggested that survival of independent (age ≥2 yr) grizzly bears was best explained by the level of human development of the landscape within the home ranges of bears. Survival improved as secure habitat and elevation increased but declined as road density, number of homes, and site developments increased. Bears living in areas open to fall ungulate hunting suffered higher rates of mortality than bears living in areas closed to hunting. Our top model strongly supported previous research that identified roads and developed sites as hazards to grizzly bear survival. We also demonstrated that rural homes and ungulate hunting negatively affected survival, both new findings. We illustrate how our survival model, when linked with estimates of reproduction and survival of dependent young, can be used to identify demographically the source and sink habitats in the GYE. Finally, we discuss how this demographic model constitutes one component of a habitat-based framework for grizzly bear conservation. Such a framework can spatially depict the areas of risk in otherwise good habitat, providing a focus for resource management in the GYE.

Idaho, Montana, Wyoming↗

USGS2022

African penguins and localized fisheries management: Response to Butterworth and Ross-Gillespie

We present a response to Butterworth and Ross-Gillespie's (2022) comment on our perspectives on how forage fish fisheries are impacting the endangered African penguin ( Sphenicus demersus ), and corresponding management options. Butterworth and Ross-Gillespie overstate model uncertainties and downplay the clear ecological and conservation significance of the fisheries closure experiment. We demonstrate that their criticism of “pseudo-replication” is weak, and not in line with their own analyses nor with the interpretations of many international scientific review panels commissioned by the government of South Africa to evaluate experimental results. Their comment does not alter our fundamental conclusions that forage fisheries operating near penguin breeding colonies compete with the birds for food resources, are detrimental to the penguin's population health, and are impeding recovery. Given that sardines are depleted (DFFE, 2021) and the African penguin is approaching a conservation crisis, we reiterate our position that continuing the precautionary approach of closures at the local scale of central-place foraging penguins is warranted to facilitate their population growth under fisheries management goals to conserve and maintain ecosystem functions.

ICES Journal of Marine Science↗

USGS2004

Status assessment and conservation plan for the yellow-billed loon (Gavia adamsii)

Because of its restricted range, small population size, specific habitat requirements, and perceived threats to its breeding habitat, the Yellow-billed Loon (Gavia adamsii) is a species of conservation concern to the U.S. Fish and Wildlife Service and the subject of a petition for listing under the Endangered Species Act. This Status Assessment synthesizes current information on population size, trends, and potential threats to Yellow-billed Loons, and the Conservation Plan identifies research and monitoring activities that would contribute to the conservation of this species. The preparation of this report was requested and funded by the U.S. Fish and Wildlife Service, Nongame Bird Office, Region 7.The Status Assessment and Conservation Plan for the Yellow-billed Loon can be summarized as follows:? Northern Alaska breeding grounds support an average of 3,369 individuals, including <1,000 nesting pairs in most years. The Yellow-billed Loon ranks as one of the 10 rarest birds that breeds regularly within the main land U.S. and one of only 20 with a North American population <16,000 individuals (Section 6-E).? There is no evidence of a long-term trend in the Yellow-billed Loon population index since 1986 (-0.9% annual change), but interpretation of surveys is complicated by changes in observers and high annual variation, and the 95% confidence interval is large (-3.6% to +1.8% annual change). The low reproductive potential of Yellow-billed Loons suggests that recovery from a substantial decline would not occur rapidly. There are no systematic surveys of Canadian and Russian breeding populations (Section 6-F).? The expansion of the oil industry into prime Yellow-billed Loon breeding habitat is a recent occurrence and we lack the necessary information to accurately predict its effect on the population. Most of northern Alaska?s Yellow-billed Loons (91%) occur on the National Petroleum Reserve?Alaska, virtually all of which is open or proposed to be opened to development and where there is no permanent or legal protection of Yellow-billed Loon habitat (Section 7-A).? Other potential factors affecting the population are also addressed, such as contaminants, subsistence hunting, by catch in subsistence and commercial fisheries on the breeding and wintering grounds, and health of the marine ecosystem off the coast of East Asia where Alaska?s Yellow-billed Loons winter, but data are lacking to reach strong conclusions on most issues.? The conservation goal adopted by the Alaska Loon and Grebe Working Group for the Yellow-billed Loon is to maintain a stable breeding population, of current size and distribution, across the extent of the loon?s breeding range in Alaska. The Conservation Plan, designed to provide information necessary to meet this goal, puts forth seven objectives: 1) Conduct annual population surveys having negligible bias and 80% statistical power to detect a 3.4% annual decline, a decline that would result in a 50% loss of the population within 20 years; 2) Obtain an unbiased and reliable estimate of the size of Alaska?s breeding population; 3) Identify geographic regions and habitats of importance during breeding, staging, and wintering periods; 4) Use demographic models to evaluate risks to the population; 5) Identify potential effects of oil development on the breeding grounds and measures necessary to minimize the effects; 6) Evaluate the magnitude of subsistence harvest and by catch and their potential effects on the population; 7) Develop a continent-wide and range-wide context for Alaska?s population and habitat objectives.

Scientific Investigations Report↗

USGS2025

Introducing disciplinary perspectives and interdisciplinary possibilities for studying recreational fishers and fisheries

Individuals from many disciplines conduct research to understand the social dimension of recreational fisheries. This diverse inquiry has produced a comprehensive understanding of the behaviours of recreational fishers, the outcomes from fishing, and the relationships among fishers, others, and the natural and human environment. The associated body of research, however, is largely disconnected across disciplines. Our goals here are to help readers understand the similarities and differences among disciplines and to identify opportunities for interdisciplinary-based research on recreational fishers. Before addressing these goals, we begin by answering basic questions: What is a discipline? What are the primary disciplines used to study recreational fishers? And what is the genealogy of research on recreational fishers? Seven key disciplines are then classified by multi-criteria related to both focus and epistemological and methodological approaches. This classification reveals clear connections among: (i) ecological science and resource economics, and to a lesser extent historical ecology; (ii) environmental history and political ecology; and (iii) behavioural economics and social psychology. We next describe and provide possible remedies for barriers that inhibit interdisciplinary research, including different epistemologies, nomenclature, and reward bias. Finally, we highlight opportunities to conduct interdisciplinary research by describing the types of benefits that each discipline can provide when conducting interdisciplinary research on recreational fisheries.

Book chapter↗

USGS2010

Lithologic and physicochemical properties and hydraulics of flow in and near the freshwater/saline-water transition zone, San Antonio segment of the Edwards aquifer, south-central Texas, based on water-level and borehole geophysical log data, 1999-2007

The freshwater zone of the San Antonio segment of the Edwards aquifer in south-central Texas (hereinafter, the Edwards aquifer) is bounded to the south and southeast by a zone of transition from freshwater to saline water (hereinafter, the transition zone). The boundary between the two zones is the freshwater/saline-water interface (hereinafter, the interface), defined as the 1,000-milligrams per liter dissolved solids concentration threshold. This report presents the findings of a study, done by the U.S. Geological Survey in cooperation with the San Antonio Water System, to obtain lithologic properties (rock properties associated with known stratigraphic units) and physicochemical properties (fluid conductivity and temperature) and to analyze the hydraulics of flow in and near the transition zone of the Edwards aquifer on the basis of water-level and borehole geophysical log data collected from 15 monitoring wells in four transects during 1999-2007. No identifiable relation between conductivity values from geophysical logs in monitoring wells in all transects and equivalent freshwater heads in the wells at the times the logs were run is evident; and no identifiable relation between conductivity values and vertical flow in the boreholes concurrent with the times the logs were run is evident. The direction of the lateral equivalent freshwater head gradient and thus the potential lateral flow at the interface in the vicinity of the East Uvalde transect fluctuates between into and out of the freshwater zone, depending on recharge and withdrawals. Whether the prevailing direction on average is into or out of the freshwater zone is not clearly indicated. Equivalent freshwater head data do not indicate a prevailing direction of the lateral gradient at the interface in the vicinity of the Tri-County transect. The prevailing direction on average of the lateral gradient and thus potential lateral flow at the interface in the vicinity of the Kyle transect likely is from the transition zone into the freshwater zone. The hypothesis regarding the vertical gradient at the East Uvalde transect, and thus the potential for vertical flow near an interface conceptualized as a surface sloping upward in the direction of the dip of the stratigraphic units, is that the potential for vertical flow fluctuates between into and out of the freshwater zone, depending on recharge and withdrawals. At the Tri-County transect, a downward gradient on the fresh-water side of the interface and an upward gradient on the saline-water side are evidence of opposing potentials that appear to have stabilized the position of the interface over the range of hydrologic conditions that occurred at the times the logs were run. At the Fish Hatchery transect, an upward gradient on the saline-water side of the interface, coupled with the assumption of a sloping interface, implies a vertical gradient from the transition zone into the freshwater zone. This potential for vertical movement of the interface apparently was opposed by the potential (head) on the freshwater side of the interface that kept the interface relatively stable over the range of hydrologic conditions during which the logs were run. The five flow logs for Kyle transect freshwater well KY1 all indicate upward flow that originates from the Glen Rose Limestone, the uppermost unit of the Trinity aquifer; and one log for well KY2 shows upward flow entering the borehole from the Trinity aquifer. These flow data constitute evidence of the potential for flow from the Trinity aquifer into the Edwards aquifer in the vicinity of the Kyle transect. Subsurface temperature data indicate that flow on average is more active, or vigorous, on the freshwater side of the interface than on the saline-water side. A hydraulic connection between the transition zone and the freshwater zone is indicated by similar patterns in the hydrographs of the 15 transect monitoring wells in and near the transition zone and three county index wel

Texas↗

USGS2015

Survival and recovery rates of mottled ducks banded in Texas and Louisiana

The Western Gulf Coast population of the mottled duck (Anas fulvigula) is dependent on the Gulf coastal marsh to complete its entire life cycle. Band recovery data can be used to monitor mottled duck populations by estimating annual survival, indexing harvest rate, and assessing movements. Band returns from hunting seasons 1997–2013 were used to evaluate factors influencing annual survival, recovery rates, and movements of mottled ducks in Texas and Louisiana. For banding years of 1997–2013, 58,349 normal, wild mottled ducks were banded and released in Texas and Louisiana. Since 2002, 86% of mottled duck bandings have occurred on the Chenier Plain of Texas and Louisiana. Hunters shot, recovered, and reported 7,061birds with bands during this period. Direct recovery rates were greater for juveniles than adults but changed little since the 1970s. Estimates of annual survival did not differ between Texas and Louisiana, but did among years and between sex and age classes. Adult male and juvenile female mottled ducks had the greatest and lowest annual survival rates, respectively. Recovery of birds banded on the Chenier Plain was four times greater for birds banded in Texas and harvested in Louisiana than banded in Louisiana and harvested in Texas. Much of the current inference of results from banding mottled ducks is limited to the Chenier Plain. To monitor the entire Western Gulf Coast population of mottled ducks, managers can consider expanding operational banding operations with annual quotas, which would improve survival and recovery estimates and allow for inference beyond the Chenier Plain region.

Louisiana, Texas↗

USGS2010

Fish habitat degradation in U.S. reservoirs

As the median age of the thousands of large reservoirs (> 200 ha) in the United States tops 50, many are showing various signs of fish habitat degradation. Our goal was to identify major factors degrading fish habitat in reservoirs across the country, and to explore regional degradation patterns. An online survey including 14 metrics was scored on a 0 (no degradation) to 5 (high degradation) point scale by 221 fisheries scientists (92% response rate) to describe degradation in 482 reservoirs randomly distributed throughout the continental United States. The highest scored sources of degradation were lack of aquatic macrophytes (41% of the reservoirs scored as 4–5), lack or loss of woody debris (35% scored 4–5), mistimed water level fluctuations (34% scored 4–5), and sedimentation (31% scored 4–5). Factor analysis identified five primary degradation factors that accounted for most of the variability in the 14 degradation metrics. The factors reflected siltation, structural habitat, eutrophication, water regime, and aquatic plants. Three degradation factors were driven principally by in-reservoir processes, whereas the other two were driven by inputs from the watershed. A comparison across U.S. regions indicated significant geographical differences in degradation relative to the factors emphasized by each region. Reservoirs sometimes have been dismissed as unnatural and disruptive, but they are a product of public policy, a critical feature of landscapes, and they cannot be overlooked if managers are to effectively conserve river systems. Protection and restoration of reservoir habitats may be enhanced with a broader perspective that includes watershed management, in addition to in reservoir activities.

Fisheries↗

USGS1989

Duck harvest on public hunting areas in California

We summarized hunter visits and success, and the magnitude and species composition of the duck harvest recorded on California public hunting areas (PHAs) during 1950-87. Hunter visits and harvest increased during 1950-74 as new PHAs were added, then declined concurrently with duck populations. Of six geographic regions, the Sacramento Valley, with numerous PHAs and the largest duck concentrations, accounted for the largest portion of PHA hunter visits (28%) and harvest (35%). Duck population levels, regulations, and hunter numbers affected PHA hunter success. Success was highest during 1955-59 but declined with no consistent trend after 1960. Species vulnerability, abundance, distribution, and hunter preference affected harvest composition. Northern pintails, Anas acuta, averaged 27% of the PHA harvest but declined in importance after 1974. Green-winged teal, A. crecca, the most important species in southern regions, averaged 21% of the PHA harvest. Mallards, A. platyrhynchos, averaged 16% of the PHA harvest but increased in importance after 1974 to become the most common duck bagged after 1983. PHA harvest comprised a small (4-16%) portion of the total state harvest. However, this portion increased from 1950-70 because of increased hunter visits to new PHAs and after 1970 because hunter success on PHAs did not decline as on other areas. PHA hunters tended to harvest fewer preferred species and more vulnerable species, as proportions of total bag, than did other hunters. The continued decline in numbers of waterfowl hunters presents important challenges for management of waterfowl areas in California.

California Fish and Game↗

USGS2013

Tracing groundwater with low-level detections of halogenated VOCs in a fractured carbonate-rock aquifer, Leetown Science Center, West Virginia, USA

Measurements of low-level concentrations of halogenated volatile organic compounds (VOCs) and estimates of groundwater age interpreted from 3 H/ 3 He and SF 6 data have led to an improved understanding of groundwater flow, water sources, and transit times in a karstic, fractured, carbonate-rock aquifer at the Leetown Science Center (LSC), West Virginia. The sum of the concentrations of a set of 16 predominant halogenated VOCs (TDVOC) determined by gas chromatography with electron-capture detector (GC–ECD) exceeded that possible for air–water equilibrium in 34 of the 47 samples (median TDVOC of 24,800 pg kg −1 ), indicating that nearly all the water sampled in the vicinity of the LSC has been affected by addition of halogenated VOCs from non-atmospheric source(s). Leakage from a landfill that was closed and sealed nearly 20 a prior to sampling was recognized and traced to areas east of the LSC using low-level detection of tetrachloroethene (PCE), methyl chloride (MeCl), methyl chloroform (MC), dichlorodifluoromethane (CFC-12), and cis-1,2-dichloroethene (cis-1,2-DCE). Chloroform (CHLF) was the predominant VOC in water from domestic wells surrounding the LSC, and was elevated in groundwater in and near the Fish Health Laboratory at the LSC, where a leak of chlorinated water occurred prior to 2006. The low-level concentrations of halogenated VOCs did not exceed human or aquatic-life health criteria, and were useful in providing an awareness of the intrinsic susceptibility of the fractured karstic groundwater system at the LSC to non-atmospheric anthropogenic inputs. The 3 H/ 3 He groundwater ages of spring discharge from the carbonate rocks showed transient behavior, with ages averaging about 2 a in 2004 following a wet climatic period (2003–2004), and ages in the range of 4–7 a in periods of more average precipitation (2008–2009). The SF 6 and CFC-12 data indicate older water (model ages of 10s of years or more) in the low-permeability shale of the Martinsburg Formation located to the west of the LSC. A two-a record of specific conductance, water temperature, and discharge recorded at 30-min intervals demonstrated an approximately 3-month lag in discharge at Gray Spring. The low groundwater ages of waters from the carbonate rocks support rapid advective transport of contaminants from the LSC vicinity, yet the nearly ubiquitous occurrence of low-level concentrations of halogenated VOCs at the LSC suggests the presence of long-term persistent sources, such as seepage from the closed and sealed landfill, infiltration of VOCs that may persist locally in the epikarst, exchange with low-permeability zones in fractured rock, and upward leakage of older water that may contain elevated concentrations of halogenated VOCs from earlier land use activities.

West Virginia↗

USGS1962

Water resources of the Utica-Rome area, New York

The Utica-Rome area is along the Mohawk River and New York State Erie (Barge) Canal about midway between Lake Ontario and Albany. It encompasses about 390 square miles centered around the industrial cities of Utica and Rome. The Mohawk River, its tributary West Canada Creek, and a system of reservoirs and diversions to maintain the flow in the barge-canal system, assure an ample water supply for the foreseeable needs of the area. The water from these sources is generally of good chemical quality requiring little treatment, although that from the Mohawk River is only fair and may require some treatment for sensitive industrial processes. Additional surface water is available from smaller streams in the area, particularly Oriskany and Sauquoit Creeks, but the water from these sources is hard, and has a dissolved-solids content of more than 250 ppm (parts per million). Ground water is available in moderate quantities from unconsolidated sand and gravel deposits in the river valleys and buried bedrock channels, and in small quantities from bedrock formations and less permeable unconsolidated deposits. The quality of water from sand and gravel, and bedrock ranges from good to poor. However, where necessary, the quality can be improved with treatment. The Mohawk River is the source of the largest quantity of water in the area. The flow of the stream below Delta Dam equals or exceeds 108 mgd (million gallons per day) 90 percent of the time, and at Little Falls it equals or exceeds 560 mgd 90 percent of the time. The flow between these two points is increased by additions from Oriskany, Sauquoit, and West Canada Creeks and from many smaller tributary streams. The flow is also increased by diversions from outside the area, from the Black and Chenango Rivers and West Canada Creek for improvement of navigation in the Erie (Barge) Canal, and from West Canada and East Branch Fish Creeks for the public supplies of Utica and Rome. Much of the public-supply water eventually reaches the river by way of sewerage and industrial waste-disposal systems. The total diversion from these sources averages more than 92 mgd. An estimated 18.5 mgd is withdrawn from the Mohawk River by industry, mostly for nonconsumptive uses. Floods in the Utica-Rome area are not a frequent problem owing to the use of regulatory measures. The major streams fluctuate through a narrow range in stage and generally only a narrow strip along the streams is subject to flooding. Water-bearing sand and gravel deposits in the major river valleys are the principal sources of ground water, especially where they are recharged by infiltration from streams. The most important potential source is the deposit of sand and gravel underlying the extensive plain adjacent to the Mohawk River between Delta Reservoir and Rome. Maximum sustained yields from these deposits are not known; but moderate quantities of water, 300 gpm (gallons per minute) or less from a single well, can probably be obtained from some parts of the sand plain area, particularly in the vicinity of a buried bedrock channel that extends southwestward from Delta Reservoir. Similar quantities of ground water probably can be withdrawn from some parts of the flood plain of the Mohawk River between Rome and Frankfort and from the sand and gravel deposits filling the valley of Ninemile Creek below Holland Patent. The deposits underlying the flood plain of the Mohawk River generally are fine grained but in places contain interstratified beds of coarser sand and gravel. The most productive part of the flood plain is at the east end near Frankfort. The deposits in Ninemile Creek valley also are generally fine grained; but where they are sufficiently thick, as over a buried bedrock valley southwest of Floyd, moderate quantities of water may be obtained. Small to moderate quantities of water (150 gpm or less from a single well) can be obtained from sand and gravel deposits in the bottoms of Oriskany and Sauquoit Creek vall

New York↗

USGS1978

Status of the peregrine falcon in the Rocky Mountains and the southwestern United States, Baja California, and Mexico (south of Texas)

About 31 pairs of peregrines still nest north of Mexico, from Idaho and Montana south through West Texas, New Mexico and Arizona. At least thirty-six additional pairs nest in Mexico. Although the nesting sites are occupied, the tissues of the peregrine?s prey species still contain high concentrations of pesticides. The eggs in some Rocky Mountain eyries have shells which are precariously thin and have high residue levels of DDE in their contents. Increasing economic development is encroaching on the peregrine habitat throughout its range in western North America. In Baja California. and Mexico south of Texas this involves increased agricultural activity including use of organochlorine pesticides, increased tourism and increased use of the Gulf of California both for commercial and sport fishing, with their potential disturbance of eyrie sites and reduction of the peregrine?s aquatic feeding prey base. As the fish in the Gulf decrease in number, some of the avian species on which peregrines prey will likewise decrease. This ultimately may effect the peregrine. These factors may have been involved in the demise of the peregrine on Baja California?s Pacific coast. Furthermore, throughout its range, residential, industrial, mining, geothermal, recreational and other types of development and land use practices sometimes destroy habitat essential to the survival of the peregrine. A recent request for the protection of an historical site in California as Critical Habitat under Section 7 of the Endangered Species Act was rejected because peregrines, although observed there, were not known to have produced eggs or young at the site for several decades. With inadequate protection of abandoned, but still suitable, historical eyrie sites, the peregrine may have an insufficient number of eyries to reoccupy in recovery attempts. The lack of present occupancy of a site, without biological evidence that the site is no longer suitable for reoccupancy, is insufficient cause to give up the site to the pressures of development. Since destruction of habitat is forever, preservation of this essential habitat is of utmost importance to the survival of the species. On the other hand, we must not allow the peregrine, or other of the endangered species, to be used as levers for the sole purpose of restricting economic development. When an impasse between the two does occur, our defense of the endangered species must be justified on sound biological evidence if the Endangered Species Act of 1973 is to survive. The formation of the recovery teams, the development of recovery plans, and the success of captive breeding and reintroduction projects are all on the plus side of the ledger for the peregrine. They suggest optimism for the future of the peregrine, providing use of DDT is restricted both north and south of our southern border, and a sufficient number of the still suitable inactive eyrie sites are preserved to effect recovery. We need to categorize all active and inactive sites on the basis of quality and/or suitability for reoccupancy and preserve those required for the recovery of the species. Categorizing inactive eyries as to suitability for reoccupancy will provide land management agencies information badly needed for critical value judgements affecting the future of the peregrine falcon in the West.

Book chapter↗

USGS2017

Five hydrologic and landscape databases for selected National Wildlife Refuges in the Southeastern United States

This report serves as metadata and a user guide for five out of six hydrologic and landscape databases developed by the U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service, to describe data-collection, data-reduction, and data-analysis methods used to construct the databases and provides statistical and graphical descriptions of the databases. Six hydrologic and landscape databases were developed: (1) the Cache River and White River National Wildlife Refuges (NWRs) and contributing watersheds in Arkansas, Missouri, and Oklahoma, (2) the Cahaba River NWR and contributing watersheds in Alabama, (3) the Caloosahatchee and J.N. “Ding” Darling NWRs and contributing watersheds in Florida, (4) the Clarks River NWR and contributing watersheds in Kentucky, Tennessee, and Mississippi, (5) the Lower Suwannee NWR and contributing watersheds in Georgia and Florida, and (6) the Okefenokee NWR and contributing watersheds in Georgia and Florida. Each database is composed of a set of ASCII files, Microsoft Access files, and Microsoft Excel files. The databases were developed as an assessment and evaluation tool for use in examining NWR-specific hydrologic patterns and trends as related to water availability and water quality for NWR ecosystems, habitats, and target species. The databases include hydrologic time-series data, summary statistics on landscape and hydrologic time-series data, and hydroecological metrics that can be used to assess NWR hydrologic conditions and the availability of aquatic and riparian habitat. Landscape data that describe the NWR physiographic setting and the locations of hydrologic data-collection stations were compiled and mapped. Categories of landscape data include land cover, soil hydrologic characteristics, physiographic features, geographic and hydrographic boundaries, hydrographic features, and regional runoff estimates. The geographic extent of each database covers an area within which human activities, climatic variation, and hydrologic processes can potentially affect the hydrologic regime of the NWRs and adjacent areas. The hydrologic and landscape database for the Cache and White River NWRs and contributing watersheds in Arkansas, Missouri, and Oklahoma has been described and documented in detail (Buell and others, 2012). This report serves as a companion to the Buell and others (2012) report to describe and document the five subsequent hydrologic and landscape databases that were developed: Chapter A—the Cahaba River NWR and contributing watersheds in Alabama, Chapter B—the Caloosahatchee and J.N. “Ding” Darling NWRs and contributing watersheds in Florida, Chapter C—the Clarks River NWR and contributing watersheds in Kentucky, Tennessee, and Mississippi, Chapter D—the Lower Suwannee NWR and contributing watersheds in Georgia and Florida, and Chapter E—the Okefenokee NWR and contributing watersheds in Georgia and Florida.

Alabama, Arkansas, Florida, Georgia, Kentucky, Mis↗

USGS2015

An updated conceptual model of Delta Smelt biology: Our evolving understanding of an estuarine fish

The main purpose of this report is to provide an up-to-date assessment and conceptual model of factors affecting Delta Smelt (Hypomesus transpacificus) throughout its primarily annual life cycle and to demonstrate how this conceptual model can be used for scientific and management purposes. The Delta Smelt is a small estuarine fish that only occurs in the San Francisco Estuary. Once abundant, it is now rare and has been protected under the federal and California Endangered Species Acts since 1993. The Delta Smelt listing was related to a step decline in the early 1980s; however, population abundance decreased even further with the onset of the “pelagic organism decline” (POD) around 2002. A substantial, albeit short-lived, increase in abundance of all life stages in 2011 showed that the Delta Smelt population can still rebound when conditions are favorable for spawning, growth, and survival. In this report, we update previous conceptual models for Delta Smelt to reflect new data and information since the release of the last synthesis report about the POD by the Interagency Ecological Program for the San Francisco Estuary (IEP) in 2010. Specific objectives include: 1. Provide decision makers with a practical tool for evaluating difficult trade-offs associated with management and policy decisions. 2. Provide scientists with a framework from which they can formulate and evaluate hypotheses using qualitative or quantitative models. 3. Provide the general public with a new way of learning about Delta Smelt and their habitat. Our updated conceptual model describes the habitat conditions and ecosystem drivers affecting each Delta Smelt life stage, across seasons and how the seasonal effects contribute to the annual success of the species. The conceptual model consists of two nested and linked levels of increasing specificity. The general life cycle conceptual model for four Delta Smelt life stages (adults, eggs and larvae, juveniles, and subadults) includes stationary ecosystem components and dynamic environmental drivers, habitat attributes, and Delta Smelt responses. The more detailed life stage transition conceptual models for each of the four Delta Smelt life stages describe relationships between environmental drivers, key habitat attributes, and the responses of Delta Smelt to habitat attributes as they transition from one life stage to the next. Our analyses and conceptual model show that good larval recruitment is essential for setting the stage for a strong year class; however, increased growth and survival through subsequent life stages are also needed to achieve and sustain higher population abundance. We used our conceptual model to generate 16 hypotheses about the factors that may have contributed to the 2011 increase in Delta Smelt relative abundance. We then evaluated these hypotheses by comparing habitat conditions and Delta Smelt responses in the wet year 2011 to those in the prior wet year 2006 and in the drier years 2005 and 2010. Larval recruitment was similarly high in both wet years and lower in the drier antecedent years, but juvenile and adult abundance increased only in 2011. In 2005 and 2006, the population was limited by very poor survival from the larval to the juvenile life stage. We found that in 2011, Delta Smelt may have benefitted from a combination of favorable habitat conditions throughout the year, including: 1. Adults and larvae benefitted from prolonged cool spring water temperatures, high 2011 winter and spring outflows which reduced entrainment risk and possibly improved other habitat conditions, and possibly enhanced food availability in late spring. 2. Juveniles benefitted from cool water temperatures in late spring and early summer as well as from improved food availability and low levels of harmful Microcystis. 3. Subadults also benefitted from improved food availability and from favorable habitat conditions in the large, low salinity zone (salinity 1-6) located more toward Suisun Bay,

California↗

USGS2017

Estimation of the groundwater resources of the bedrock aquifers at the Kettle Moraine Springs State Fish Hatchery, Sheboygan County, Wisconsin

Groundwater resources information was needed to understand regional aquifer systems and water available to wells and springs for rearing important Lake Michigan fish species at the Kettle Moraine Springs State Fish Hatchery in Sheboygan County, Wisconsin. As a basis for estimating the groundwater resources available, an existing groundwater-flow model was refined, and new groundwater-flow models were developed for the Kettle Moraine Springs State Fish Hatchery area using the U.S. Geological Survey (USGS) finite-difference code MODFLOW. This report describes the origin and construction of these groundwater-flow models and their use in testing conceptual models and simulating the hydrogeologic system. The study area is in the Eastern Ridges and Lowlands geographical province of Wisconsin, and the hatchery property is situated on the southeastern edge of the Kettle Moraine, a north-south trending topographic high of glacial origin. The bedrock units underlying the study area consist of Cambrian, Ordovician, and Silurian units of carbonate and siliciclastic lithology. In the Sheboygan County area, the sedimentary bedrock sequence reaches a thickness of as much as about 1,600 feet (ft). Two aquifer systems are present at the Kettle Moraine Springs State Fish Hatchery. A shallow system is made up of Silurian bedrock, consisting chiefly of dolomite, overlain by unconsolidated Quaternary-age glacial deposits. The glacial deposits of this aquifer system are the typical source of water to local springs, including the springs that have historically supplied the hatchery. The shallow aquifer system, therefore, consists of the unconsolidated glacial aquifer and the underlying bedrock Silurian aquifer. Most residential wells in the area draw from the Silurian aquifer. A deeper confined aquifer system is made up of Cambrian- and Ordovician-age bedrock units including sandstone formations. Because of its depth, very few wells are completed in the Cambrian-Ordovician aquifer system (COAS) near the Kettle Moraine Springs State Fish Hatchery. Three groundwater-flow models were used to estimate the water resources available to the hatchery from bedrock aquifers under selected scenarios of well placement and seasonal water requirements and subject to constraints on the effects of pumping on neighboring wells, local springs, and creeks. Model input data (recharge, water withdrawal, and boundary conditions) for these models were compiled from a number of data and information sources. The first model, named the “KMS model,” (KMS stands for Kettle Moraine Springs) is an inset model derived from a published USGS regional Lake Michigan Basin model and was constructed to simulate groundwater pumping from the semiconfined Silurian aquifer. The second model, named the “Pumping Test model,” was constructed to evaluate an aquifer pumping test conducted in the COAS as part of this project. The Pumping Test model was also used to simulate the local effects of 20 years of groundwater pumping from this deep bedrock aquifer for future hatchery operations. The third model, named the “LMB modified model,” is a version of the published Lake Michigan Basin (LMB) model that was modified with aquifer parameters refined in an area around the hatchery (approximately a 5-mile radius circle, corresponding to the area stressed by the aquifer pumping test). This LMB modified model was applied to evaluate regional effects of pumping from the confined COAS. The available Silurian aquifer groundwater resource was estimated using the KMS model with three scenarios—named “AllConstraints,” “Constraints2,” and “Constraints3”—that specified local water-level and flow constraints such as drawdown at nearby household wells, water levels inside pumping well boreholes, and flow in local streams and springs. Each scenario utilized the MODFLOW Groundwater Management Process (GWM) to select three locations from six candidate locations that provided the greatest combined flow while satisfying the constraints. The three constraint scenarios provided estimates of 430 gallons per minute (gal/min), 480 gal/min, and 520 gal/min pumping from three wells—AllConstraints, Constraints2, and Constraints3, respectively. The same three wells were selected for the scenarios that estimated 480 gal/min and 520 gal/min; the scenario that estimated 430 gal/min shared two of these same wells, but the third selected well was different. The available COAS groundwater resource was estimated by two scenarios with each conducted over a period of 20 years with the Pumping Test model and the LMB modified model . The Pumping Test model was used to simulate local effects of pumping, and the LMB modified model was used to simulate regional effects of pumping. The scenarios simulate a range of total and seasonal pumping rates potentially linked to site activities. Scenario 1 simulates two wells completed in the Cambrian-Ordovician aquifer system, each pumping for 8 months at 300 gal/min, followed by pumping for 4 months at 600 gal/min. The average yearly pumping rate of Scenario 1 is 800 gal/min. Scenario 2 simulates three wells completed in the Cambrian-Ordovician aquifer system pumping for 8 months at 200 gal/min, followed by pumping for 4 months at 500 gal/min. The average yearly pumping rate of Scenario 2 is 900 gal/min. The Pumping Test model simulations confirmed that drawdown in the boreholes of the pumping wells at the selected 2-well or 3-well rates will meet the desired condition that the pumping water level remains at least 100 ft above the highest Cambrian-Ordovician unit open to the well. The LMB modified model was used to evaluate the regional drawdown of the pumping from the confined COAS under the same 2-well and 3-well scenarios. At the nearest known existing COAS well, Campbellsport production well #4, the simulated drawdown for Scenario 1 after 20 years of cyclical pumping with two pumping wells averaging a total of 800 gal/min is 16.9 ft, whereas the simulated drawdown for Scenario 2 after 20 years of pumping with three pumping wells averaging a total of 900 gal/min is 19.0 ft. The total deep aquifer thickness at the Campbellsport location is on the order of 620 ft, meaning that the simulated drawdown for either scenario is about 3 percent of the confined aquifer thickness. The models developed as part of this project are archived in the project data release. The archive includes the model input and output files as well as MODFLOW source code and executables. ( Haserodt and others, 2017 ).

Wisconsin↗

USGS2021

Groundwater/surface-water interactions in the Partridge River Basin and evaluation of hypothetical future mine pits, Minnesota

The Partridge River Basin (PRB) covers 156 square miles in northeastern Minnesota with headwaters in the Mesabi Iron Range. The basin is characterized by extensive wetlands, lakes, and streams in poorly drained and often thin glacial material overlying Proterozoic bedrock. To better understand the interaction between these extensive surface water features and the groundwater system, a three-dimensional, steady-state, groundwater-flow model of the PRB was developed by the U.S. Geological Survey in cooperation with the Great Lakes Indian Fish & Wildlife Commission using the finite-difference computer code MODFLOW-NWT. The model simulates steady-state base flow in streams and groundwater interactions using the streamflow routing (SFR2) package. Existing mining features including tailings basins, stockpiles, pumped mine pits, and flooded mine pits were simulated using either high hydraulic conductivity zones or the drain (DRN) package. The unsaturated zone flow (UZF) package was used to better represent the groundwater system in areas with a high water table and for wetlands often associated with such areas. UZF typically is used to represent unsaturated zone processes but also can simulate the rejection of recharge and groundwater discharge to the land surface when the water table is near land surface. The steady-state model used data from the 2011 to 2013 period when 2011 high-resolution land surface (light detecting and ranging [lidar]) data were available that reflected land-surface and water elevations from mining activity in the basin. The parameter-estimation software suite PEST_HP was used to obtain a best fit of the modeled to measured groundwater levels, streamflow, pit inflow rates, and mapped peat deposits. The PEST calibration used the target residuals from two models with the same model parameters and targets from two separate periods: (1) a 1995–2015 calibration model, which provided a larger number of calibration targets, and (2) a 2011–2013 mining conditions model, which included calibration targets that reflected conditions consistent with the modeled mine-workings topography. Calibration of the PRB model resulted in ranges of glacial horizontal hydraulic conductivity parameters that generally agreed with literature values and other models of the region. Horizontal hydraulic conductivity of the bedrock was higher in the upper bedrock layers where numerous and continuous fractures have been observed and lower in the deeper bedrock layers. Average basin-wide calibrated infiltration was 5.3 inches per year. An average of 4.6 inches per year of infiltration crosses the water table and becomes recharge and 0.7 inch per year is rejected by UZF due to saturated conditions at the land surface. Simulated groundwater runoff (the sum of rejected recharge and groundwater seepage to the land surface) can either be routed to streams or removed from the model as evapotranspiration. The calibrated model indicates relatively shallow groundwater-flow paths dominating and approximately 50 percent of the stream base flow coming from groundwater runoff. The 2011–2013 mining conditions model was then used to develop five model scenarios simulating the response of the groundwater and surface-water system to potential hydrologic stress. The purpose of these mine pit scenarios is to present a possible workflow to quantify a model’s uncertainty for a given model forecast and serve as a possible guide for initial data collection that may improve a future model’s ability to make such a forecast. The scenarios included one scenario with the currently existing Peter Mitchell pit at final buildout and flooded to an elevation of 1,500 feet, and four scenarios with a hypothetical, new mine pit plus the flooded Peter Mitchell at final buildout. The five model scenarios were used to forecast streamflow at six locations in the PRB, pit inflow rates for the new mine pits and the flooded Peter Mitchell pit, and the average depth to water in 12 wetlands. A linear uncertainty analysis was performed using information from the PEST calibration and tools in the PyEMU python package to assess model uncertainty propagation to the model forecasts. Streamflows generally were reduced with future mining and the greatest streamflow reductions occurred from the flooded Peter Mitchell Pit, probably due to its large size. Average depth to groundwater in wetlands was most affected the closer the wetland was to a new mine pit. Linear uncertainty methods were also used to evaluate data worth, which is the ability for potential new groundwater elevation observations to reduce the uncertainty in scenario forecasts. Data worth was performed for a grid of new hydraulic head observations. Overall, areas with nonnegligible data worth generally corresponded to wetland areas with no groundwater seepage to land surface from UZF. These model behaviors indicated that the land-surface boundary condition simulated by the UZF package was pinning the groundwater elevations to the land surface in areas with groundwater seepage (33 percent of the 2011–2013 base conditions model) such that the sensitivity to new observations in these areas was minimal. Therefore, representing wetlands as boundary conditions minimized the usefulness of data worth calculations because wetland areas were present over a large part of the model domain. Probabilistic capture zones were estimated for each of the mines in the model scenarios. A capture zone represents the area contributing recharge to a model feature, like a well or a mine pit, and can be calculated by forward tracking particles from the water table. By using Monte Carlo techniques, it is possible to generate estimated capture zones that include the probability of recharge capture given the uncertainty present in the model. Monte Carlo techniques use randomly generated model parameter sets sampled from a plausible parameter range to create many possible realizations. The resulting capture zone arrays were calculated by tallying the total number of realizations in which a particle from a model cell was captured by the feature. Probabilities from the Monte Carlo runs ranged from 1 (captured in 100 percent of the runs) near the pits to 0 (captured in 0 percent of the runs) at the edges of the capture zone. Capture zones were not always spatially continuous; for example, the capture zone for the proposed mine pits south of the flooded Peter Mitchell pit was discontinuous with capture surrounding the proposed mine pit and north of the flooded Peter Mitchell pit. This northern section represents deeper groundwater flow paths that originate in the topographic high, move under the flooded pit, and discharge into the proposed pit. This pattern of capture indicates the possibility of some deeper flow through the upper fractured bedrock when the shallow groundwater flow system is modified. These results underscore that future site-specific applications of the base condition model require the input of site-specific data and recalibration to focus on the site of interest.

Minnesota↗

USGS2000

Hydrology and water and sediment quality at James Campbell National Wildlife Refuge near Kahuku, Island of Oahu, Hawaii

The James Campbell National Wildlife Refuge occupies two lowland marsh and pond complexes on the northern coastal plain of Oahu: the mostly natural ponds and wetlands of the Punamano Unit and the constructed ponds of the Kii Unit. The U.S. Fish and Wildlife Service manages the Refuge primarily to protect and enhance habitat for four endangered species of Hawaiian waterbirds. Kii Unit is fed by artesian wells and rainfall, whereas Punamano Unit is fed naturally by rainfall, runoff, and ground-water seepage. Streams drain from the uplands into lowland ditches that pass through Kii Unit on their way to the ocean. A high-capacity pump transfers water from the inner ditch terminus at Kii to the ocean outlet channel. Stormwaters also exit the inner ditch system over flood-relief swales near the outlet pump and through a culvert with a one-way valve. A hydrologic investigation was done from November 1996 through February 1998 to identify and quantify principal inflows and outflows of water to and from the Refuge, identify hydraulic factors affecting flooding, document ground-water/surface-water interactions, determine the adequacy of the current freshwater supply, and determine water and sediment quality. These goals were accomplished by installing and operating a network of stream-gaging stations, meteorology stations, and shallow ground-water piezometers, by computing water budgets for the two Refuge units, and by sampling and analyzing water and pond-bottom sediments for major ions, trace metals, and organic compounds. Streamflow during the study was dominated by winter stormflows, followed by a gradual recession of flow into summer 1997, as water that had been stored in alluvial fans drained to lowland ditches. Outflow at the ditch terminus in 1997 was 125 million gallons greater than measured inflow to the coastal plain, mainly reflecting gains from ground water along the ditches between outlying gages and the ditch terminus. Of the measured 1997 outflow, 98 percent was through the Kii outlet pump, with the outlet culvert valve only opening for brief periods during storms. Large volumes of stormflow overflowed the flood-relief swales unmeasured. The largest storm of the study, in November 1996, was estimated to have a flood frequency of about 3 to 4 years. Streamflow exceeded culvert capacity and overtopped Kamehameha Highway at Kalaeokahipa Stream and Hospital ditch. Slight overbank flooding in Kii ditch resulted strictly from high discharge. Minor overbank flooding farther out on the coastal plain probably was caused mainly by the small hydraulic gradients available to convey stormflows along the lowland ditches. Stormwaters flooded Kii ponds and flowed back upstream along Punamano ditch into Punamano marsh, introducing suspended sediment and possibly other contaminants to the Refuge. Two smaller storms in January 1997 resulted in smaller flows and no overbank flooding. The Kii outlet pump ran continuously for 7 days during the November 1996 storm and for 1 to 2 days during the January 1997 storms. During all three storms, the outlet culvert valve opened and the inner ditches overtopped the flood-relief swales, allowing free outflow of water from the inner ditch. Backwater effects hindered drainage during the January 1997 storms at Hospital ditch at Kamehameha Highway, and at Punamano ditch at Nudist Camp Road (where the backflow into Punamano marsh in November 1996 constituted an extreme backwater effect). A probable marine backwater effect was imposed at the ocean outlet ditch during the November 1996 storm through a combination of high spring tides and wave setup from large surf. Whether this backwater effect propagated upstream in the ditches to affect inland sites could not be determined conclusively. A sand plug may have built up in the ocean outlet channel before the November 1996 storm, but if so, it probably washed out prior to, or early in the storm, and was not present at the time of peak stage at inland sites. A season-long buildup of the sand plug in late 1997 was inferred from rising water levels in the outlet ditch. Seawater flows up the outlet channel or over the sand berm and into the outer ditch system on most high tides, and particularly during spring high tides. Ponds and ditches of the Refuge and surrounding lowlands have mud- and clay-lined bottoms that form an effective confining unit and inhibit interaction with an underlying shallow limestone aquifer. At Kii Unit, pond levels are higher than adjacent ditch levels and underlying ground-water levels, establishing lateral and downward head gradients that could foster seepage losses from the ponds. Regional ground-water discharge from the Koolau aquifer to the coastal-plain sediments is mostly diffuse, but is concentrated where ridges of Koolau Basalt plunge beneath coastal-plain sediments near Punamano Unit and at the head of Hospital ditch. Kii ditch gains brackish ground water downstream of Kamehameha Highway. Wastewater disposal from the sewage treatment plant adjoining Kii Unit poses little or no threat to Refuge habitat. Disposal is at six injection wells located 0.45 mi away at Kahuku, and the wells inject into confined limestone aquifers that do not extend to Kii Unit. The natural freshwater supply to Punamano Unit is adequate for maintaining the wildlife habitat, judging from stable pond levels and low salinities there. A monthly water budget for Punamano showed an apparent annual deficit in measurable flows in 1997, requiring unmeasured ground-water gains equalling 51 inches of water. The freshwater supply to Kii Unit is inadequate according to Refuge managers, because there is not enough water to manipulate levels adequately in the ponds during most of the year, and particularly during the driest months. This is confirmed by monthly deficits in the water budget for the Kii ponds during summer months. However, the Kii budget showed an annual surplus in measurable flows for 1997 equalling 24 inches of water. Unmeasured losses are required to explain the apparent annual surplus, such as discharge to the ditches through pond water-control structures and downward and/or lateral ground-water seepage. The apparent surplus at Kii is strictly hydrologic and is not a surplus in a management sense; it cannot be stored or used to supply the Refuge, but instead reflects losses from the system that render this amount of water unavailable for use. The budget year, 1997, was drier than normal (24 percent below long-term mean rainfall) and so the measured potential evaporation for 1997 was probably higher than the long-term mean. Few metals or organic compounds of potential concern were detected in pond and ditch waters and in pond-bottom sediments. Detected pesticides were at trace levels or just above minimum reporting limits. Exceptions that exceeded quality guidelines for freshwater sediment were copper and zinc in sediment from Kii ponds C and D, and copper in sediment from Punamano north pond. Therefore, urban and agricultural runoff probably have contributed little in the way of harmful metals or organic compounds to the Refuge, although the potential for such contribution remains from periodic flooding of the ponds by ditch stormflows. Salinity was low throughout most Refuge waters, qualifying as fresh to slightly brackish and suitable for the environmental needs of Refuge fauna. Higher salinities have been observed in ditches during past periods of sugarcane cultivation and saltwater aquaculture, however. Resumption of saltwater aquaculture could raise ditch salinities if saltwater effluents are disposed directly into the ditches, as they were in the past.

Hawaii↗