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At least 1,153 records · Page 64Linked to original sources
USGS2001

Summary of and factors affecting pesticide concentrations in streams and shallow wells of the lower Susquehanna River basin, Pennsylvania and Maryland, 1993-95

This report presents the detection frequency of 83 analyzed pesticides, describes the concentrations of those pesticides measured in water from streams and shallow wells, and presents conceptual models of the major factors affecting seasonal and areal patterns of pesticide concentrations in water from streams and shallow wells in the Lower Susquehanna River Basin. Seasonal and areal patterns of pesticide concentrations were observed in 577 samples and nearly 40,000 pesticide analyses collected from 155 stream sites and 169 shallow wells from 1993 to 1995. For this study, shallow wells were defined as those generally less than 200 feet deep. The most commonly detected pesticides were agricultural herbicides?atrazine, metolachlor, simazine, prometon, alachlor, and cyanazine. Atrazine and metolachlor are the two most-used agricultural pesticides in the Lower Susquehanna River Basin. Atrazine was detected in 92 percent of all the samples and in 98 percent of the stream samples. Metolachlor was detected in 83 percent of all the samples and in 95 percent of the stream samples. Nearly half of all the analyzed pesticides were not detected in any sample. Of the 45 pesticides that were detected at least once, the median concentrations of 39 of the pesticides were less than the detection limit for the individual compounds, indicating that for at least 50 percent of the samples collected, those pesticides were not detected. Only 10 (less than 0.025 percent) of the measured concentrations exceeded any established drinking-water standards; 25 concentrations exceeded 2 mg/L (micrograms per liter) and 55 concentrations exceeded 1 mg/L. None of the elevated concentrations were measured in samples collected from streams that are used for public drinking-water supplies, and 8 of the 10 were measured in storm-affected samples. The timing and rate of agricultural pesticide applications affect the seasonal and areal concentration patterns of atrazine, simazine, chlorpyrifos, and diazinon observed in water from wells and streams in the Lower Susquehanna River Basin. Average annual pesticide use for agricultural purposes and nonagricultural pesticide use indicators were used to explain seasonal and areal patterns. Elevated concentrations of some pesticides in streams during base-flow and storm-affected conditions were related to the seasonality of agricultural-use applications and local climate conditions. Agricultural-use patterns affected areal concentration patterns for the high-use pesticides, but indicators of nonagricultural use were needed to explain concentration patterns of pesticides with smaller amounts used for agricultural purposes. Bedrock type influences the movement and discharge of ground water, which in turn affects concentration patterns of pesticides. The ratio of atrazine concentrations in stream base flow to concentrations in shallow wells varied among the different general rock types found in the Lower Susquehanna River Basin. Median concentrations of atrazine in well water and stream base flow tended to be similar in individual areas underlain by carbonate bedrock, indicating the connectivity of water in streams and shallow wells in these areas. In areas underlain by noncarbonate bedrock, median concentrations of atrazine tended to be significantly higher in stream base flow than in well water. This suggests a deep ground-water system that delivers water to shallow wells and a near-surficial system that supplies base-flow water to streams. In addition to the presence or absence of carbonate bedrock, pesticide leaching potential and persistence, soil infiltration capacity, and agricultural land use affected areal patterns in detection frequency and concentration differences between samples collected from streams during base-flow conditions and shallow wells.

Water-Resources Investigations Report↗
USGS2012

Introduction to emergent wetlands: Chapter A in Emergent wetlands status and trends in the northern Gulf of Mexico: 1950-2010

Throughout the past century, emergent wetlands have been declining across the Gulf of Mexico. Emergent wetland ecosystems provide a plethora of resources including plant and wildlife habitat, commercial and recreational economic activity, water quality improvement, and natural barriers against storms. As emergent wetland losses increase, so does the need for information on the causes and effects of these losses, for emergent wetland mapping, for monitoring and restoration efforts, and for increased education. The U.S. Geological Survey (USGS) and the U.S. Environmental Protection Agency’s Gulf of Mexico Program Office (EPA GMPO) are committed to providing the best science to restore, enhance, and protect these important ecosystems. The Emergent Wetlands Status and Trends Report is a continuation of the completed Seagrass Status and Trends in the Northern Gulf of Mexico Report (Handley and others, 2007), both of which serve to update the EPA GMPO Status and Trends of Emergent and Submerged Vegetated Habitats of Gulf of Mexico Coastal Waters, USA Report (Duke and Kruczynski, 1992). The Emergent Wetlands Status and Trends Report is also part of the Gulf of Mexico Alliance Ecosystems Integration and Assessment Priority Issue Team’s work plan to provide resources that will aid in the ecological and economic enhancement of the Gulf of Mexico region. The purpose of this report is to provide scientists, managers, and citizens with valuable baseline information on the status and trends of emergent wetlands along the coast of the Gulf of Mexico. The study upon which this report is based examines the emergent wetlands of eight individual estuarine areas within the northern Gulf of Mexico region and presents statewide summaries for Texas, Louisiana, Mississippi, Alabama, and Florida. Each estuarine area is detailed in vignettes that address current status and historical trends of estuarine and palustrine emergent wetlands, emergent wetlands mapping and monitoring, causes of status change, restoration and enhancement activities, background information for the study area, and the methodology employed to analyze and document the historical trends and current status of emergent wetlands. The eight individual estuarine areas examined in this report are:  Corpus Christi/ Nueces/Aransas Bays, Tex.  Galveston Bay, Tex.  Barataria/Terrebonne Bay, La.  Mississippi Delta, La.  Mississippi Sound, Miss.  Mobile Bay, Ala.  Florida Panhandle, Fla.  Tampa Bay, Fla.

Report↗
USGS2021

Beach placer mineral deposits along localized paleoshorelines of the western Interior Seaway, upper cretaceous Fox Hills sandstone, eastern Denver Basin, Colorado

Beach placers deposited within the Fox Hills Sandstone along the eastern flank of the Denver Basin contain minerals deemed critical in 2018 by the U.S. Department of the Interior. These marine beach placers, or paleoplacers, were deposited in the Late Cretaceous along the western edge of the retreating Western Interior Seaway (WIS). Preliminary investigations determined that these deposits contain potential critical mineral resources including titanium, zirconium, hafnium, and rare earth elements (REE). This report contains the results of a limited investigation conducted by the CGS in this area to provide additional information on the nature of these mineral deposits. The following tasks were completed during this investigation: review and summary of publicly available documents and publications; collection of samples and stratigraphic analysis of accessible outcrops; mineralogical analysis of select samples; and laboratory analysis of samples for select critical mineral concentrations. This report may assist with future mineral exploration efforts in this area and provide insight into the retreat of the WIS during the Late Cretaceous.

Report↗
USGS1990

Opportunities to protect instream flows and wetland uses of water in Florida

This document combines the efforts of several individuals, agencies, and organizations toward a common objective: the identification, description, and preliminary evaluation of promising opportunities for protecting instream uses of water under existing laws in Florida. this report is intended for the use of State and Federal planning and management personnel who need an overview of potential opportunities for preserving instream flows. It is not intended to replace or challenge the advice of agency counsel, nor is it written to provide legal advice. Instead, it is designed as a guide for the person trying to find his way among sometimes bewildering State statutes and administrative practices. This report is not, and should not be taken as, official policy or prediction of future actions by any agency. It is simply a summary of some potential opportunities for protecting instream uses. Toward these objectives, the U.S. Fish and Wildlife Service, through its Water Resource Analysis Project, contracted in 1977 with R. Dewsnup and D. Jensen to identify available strategies under State and Federal laws, interstate compacts, and water quality laws. A second firm, Enviro Control, Inc., was contracted to evaluate the most promising strategies. The resulting documents reported instream flow strategies for 11 States. These reports have been revised, updated, and combined in a number of new monographs, and the Service has added more States to this service over the years. The discussion of instream flow programs and opportunities for each State is written so that each report can be read independently, with minimal cross-referencing from one State report to another. The opportunities for Florida are summarized in the table.

Report↗
USGS1994

Paleogene stratigraphy of the Solomons Island, Maryland, corehole

The Solomons Island corehole was drilled in the hope of obtaining a continuous and more nearly complete section of upper Paleocene and lower Eocene strata than are found in the discontinuous and fragmentary sections in the outcrop belt to the west. Consultation with Harry Hansen (Maryland Geological Survey) on possible drilling sites that were within the limits of our equipment and funding led to the selection of Solomons Island. A strong factor in this selection was the stratigraphic information available from the nearby Lexington Park well (Hansen and Wilson, 1984). As anticipated, all Paleogene units previously reported in the Maryland and Virginia Coastal Plain, except for the upper Eocene Chickahominy Formation and the upper Oligocene Old Church Formation, were penetrated at Solomons Island. The upper part of the Solomons Island corehole also penetrated the Calvert Formation of Miocene age and the younger Lowland Deposit. Gibson and Andrews (1994) described the lithology and biostratigraphy of these Miocene sediments. This paper describes the lithologies of the Lower Cretaceous, Paleocene, and Eocene strata that were recovered from the Solomons Island corehole and gives a brief biostratigraphic and paleoenvironmental summary of the beds penetrated there.

Maryland↗
USGS2025

Relative abundance, seasonal occurrence, and distribution of marine birds in the northern Gulf of Mexico

Marine birds in the U.S. Gulf of Mexico have long been poorly studied. Given statutory obligations to protect migratory birds and endangered species, three broad-scale vessel and aerial programs initiated since 2010 have now surveyed the entire northern Gulf. Vessel coverage alone exceeds 700 d and 74,000 km of observer effort using 300-m strip transects. We supplemented these survey data with earlier, smaller-scale studies, eBird checklists, literature reviews, and other less accessible sources to create snapshot summaries of relative abundance, seasonal occurrence, and regional distribution for 117 taxa of marine and water birds reported from the northern Gulf (113 of which were substantiated with physical evidence). Using taxonomic and functional criteria, we identified 56 taxa characteristic of open shelf, slope, and pelagic waters (federal jurisdiction), 41 taxa with primarily coastal affinities (state and federal jurisdiction), and 20 taxa of sea and diving ducks. High species richness of marine birds in the northern Gulf is attributed to (1) a temperate-to-tropical gradient facilitating diverse marine environments year-round; (2) varied geographic origins of marine bird species using the Gulf; and (3) a mostly enclosed sea basin acting as a vagrant trap for wide-ranging species. Our taxonomic list and status updates seek to bridge information gaps for marine birds now subject to accelerated commercial uses of this region's continental shelf, including newly proposed offshore wind energy development. Other applications include guiding risk and vulnerability assessments of Gulf marine birds, providing core content for seabird observer training, and prioritizing environmental impact reviews and monitoring programs in offshore energy construction and operations plans.

Marine Ornithology: Journal of Seabird Research an↗
USGS1995

Structure of the basins and ranges, Southwest New Mexico, an interpretation of seismic velocity sections

This report presents a geologic appraisal of seismic velocity sections that profile a total of 790 km in southwest New Mexico west of Las Cruces and south of Lordsburg and Deming. The present work outlines the contribution of these velocity sections to estimating areas favorable for mineral resource occurrences. Seismic refraction surveys are carried out with the initial goal of estimating the subsurface distribution of acoustic compressional velocity (Vp), which may ultimately be interpreted to provide information on lithology, geologic structure, and the occurrence of natural resources. The seismic sections presented here show velocity detail having dimensions of 100's to 1000's of meters to a depth of about 2.5 km, and across a net of traverses that profile most basins well as several ranges in the study area. Figure 1 shows the location of the seismic refraction lines. The lines are designated 1, 2, 3, 4, 5, and 7; there is no line 6. The survey covers a broad swath of the southwest Basin and Range Province extending from the Arizona border eastward to the Rio Grande River, and from the Mexican border to about lat. 32° 30' N. Lines 1, 3, and 7 traverse the axis of basins in roughly northsouth directions; the remaining lines 2, 4, and 5 trend east-west and cross various ranges and basins. Seismic data that have been collected in this region include deep-crustal refraction traverses by university scientists and commercial seismic reflection profiles acquired for petroleum exploration. Results of deep-crustal refraction studies are reviewed to provide a regional setting for the higher resolution refraction data. Results from seismic reflection will not be discussed. Industry reflection data in the area are not generally available for non-proprietary use. The nearest reflection data publicly available are in the Socorro area, about 80 km north of the present study area (Brown and others, 1980). These data were acquired by the Consortium for Continental Reflection Profiling (COCORP), a public-supported research group, to investigate the possibility of magma beneath part of the Rio Grande valley. Up to 1978 there were about 36 deep borings in the region of southwest New Mexico (Thompson and others, 1978). This drilling resulted mainly from an evaluation of petroleum potential of the Pedrogosa basin which is an extensive area of Paleozoic subsidence in Arizona, New Mexico, and Mexico that accumulated about three kilometers of Paleozoic sedimentary rock (Zeller, 1965; Thompson and others, 1978). Of these drill holes, 25 are close enough to the present seismic sections to provide correlations of velocity to lithology, and to provide an estimate of the errors associated with depth-to-interface interpretations. This information is summarized prior to considering the implications of the seismic sections in detail. The major portion of the report centers around two plates: Plate I shows seismic lines and selected drill hole locations superimposed on gravity contours, and Plate II shows velocitysections with drill hole summaries. These plates provide the foundation for developing inferences on buried lithologic, structural, and mineral resources for the region.

New Mexico↗
USGS2007

Synthesis of U.S. Geological Survey science for the Chesapeake Bay ecosystem and implications for environmental management

The purpose of this report is to present a synthesis of the USGS Chesapeake Bay science related to the 2001-06 goals and provide implications for environmental management. The report provides USGS findings that address the science needs of the Chesapeake Bay Program (CBP) restoration goals and includes summaries of 1. land-use change; 2. water quality in the watershed, including nutrients, sediment, and contaminants; 3. long-term changes in climate and estuarine water quality; 4. estuary habitats, focusing on submerged aquatic vegetation (SAV) and tidal wetlands; and 5. factors affecting fish and waterbird populations.

Delaware, Maryland, New York, Pennsylvania, Virgin↗
USGS1992

Water resources of Massachusetts

This report describes the water resources of Massachusetts. It contains sections describing the location, use, quality, and management of water resources in Massachusetts, followed by a summary of the surface water and ground-water resources of all 27 river basins designated by the State for planning purposes. The data for each basin include information about selected continuous record streamflow-gaging stations, the distribution and size of major lakes and streams, and the character of the principal aquifers. Each basin summary is accompanied by a map that shows basin and political boundaries, hydrography, locations of continuous-record streamflow-gaging stations, and aquifer areas. The aquifer areas were derived from the Hydrologic Investigations Atlases and generally show areas that are likely to yield 100 gallons per minute or more to individual wells. The report was compiled from many reports, including 30 U.S. Geological Survey Hydrologic Investigations Atlases that inventory water resources of the State.

Massachusetts↗