SEARCH · Search USGS
Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
This report is one in an annual series of reports that depicts water-level altitudes and water-level changes since 1990 in the Chicot and Evangeline aquifers in Fort Bend County and adjacent areas, Texas.
This report is one in an annual series of reports that depicts water-level altitudes and water-level changes since 1977 and compaction since 1973 in the Chicot and Evangeline aquifers in the Houston-Galveston region, Texas.
This report is one in an annual series of reports that depicts water-level altitudes and water-level changes since 1990 in the Chicot and Evangeline aquifers in Fort Bend County and adjacent areas, Texas. The report, prepared in cooperation with the Ford Bend Subsidence District, presents maps for the Chicot and Evangeline aquifers showing the approximate water-level altitudes in wells in 1998 and approximate water-level changes in wells from 1990 to 1998 and from 1997 to 1998. The most recent previously published water-level-altitude maps and water-level-change maps for the two aquifers are by Coplin and others (1997). The earliest water-level-altitude maps and water-level-change maps for the Chicot aquifer are by Wesselman (1972). The first maps of water-level altitudes and water-level changes for the Chicot and Evangeline aquifers are by Locke (1990).
This report is one in an annual series of reports that depicts water-level altitudes and water-level changes since 1977 and compaction since 1973 in the Chicot and Evangeline aquifers in the Houston-Galveston region, Texas. The report, prepared in cooperation with the City of Houston and the Harris-Galveston Coastal Subsidence District, presents maps for the Chicot and Evangeline aquifers showing the approximate water-level altitudes in wells in 1998 and approximate water-level changes in wells from 1977 to 1998 and from 1997 to 1998, a map showing extensometer site locations, and graphs showing measured compaction of subsurface material at selected sites from 1973 to 1997. The most recent previously published water-level-altitude maps and water-level-change maps for the two aquifers in the region are by Kasmarek and others (1997). The Houston-Galveston region comprises Harris and Galveston Counties and adjacent parts of Brazoria, Fort Bend, Waller, Montgomery, Liberty, and Chambers Counties.
This report is one in an annual series of reports that depicts water-level altitudes and water-level changes since 1977 and compaction since 1973 in the Chicot and Evangeline aquifers in the Houston-Galveston region, Texas. The report, prepared in cooperation with the City of Houston and the Harris-Galveston Coastal Subsidence District, presents maps for the Chicot and Evangeline aquifers showing the approximate water-level altitudes in wells in 1999 and approximate water-level changes in wells from 1977 to 1999 and from 1998 to 1999, a map showing extensometer site locations, and graphs showing measured compaction of subsurface material at selected sites from 1973 to 1998. The most recent previously published water-level-altitude maps and water-level-change maps for the two aquifers in the region are by Coplin (1998). The Houston-Galveston region comprises Harris and Galveston Counties and adjacent parts of Brazoria, Fort Bend, Waller, Montgomery, Liberty, and Chambers Counties.
For almost two decades Little Galloo Island (LGI) has supported a large colony of Double-crested Cormorants ( Phalacrocorax auritus ) in the eastern basin of Lake Ontario. Cormorant nest counts on the island since the early 1990's have averaged 4,297 per year. However, less than 2,000 pairs have nested on the island in three of the past five years. The highest count was reached in 1996 with 8,410 nesting pairs on the island. Johnson et al. (2013) estimated that cormorants from LGI alone have consumed 504 million fish since 1992. The proliferation of cormorants in the eastern basin of Lake Ontario coincided with declines in two important recreational fish species, smallmouth bass ( Micropterus dolemieu ) and yellow perch ( Perca falvescens ). Lantry et al. (2002) and Burnett et al. (2002) provide convincing evidence linking cormorant population increases to declining eastern basin smallmouth bass and yellow perch stocks. Decline of these fish stocks was evident only in the eastern basin, suggesting a localized problem, which is consistent with the halo effect where large piscivorous waterbird colonies may deplete local fish stocks (Birt et al. 1987). The year 2013 marked the twenty second consecutive year of study of the food habits and fish consumption of LGI cormorants and the fifteenth consecutive year evaluating the efficacy of management activities to control the reproductive success of cormorants nesting at LGI. The program consists mainly of spraying cormorant eggs with food grade vegetable oil as well as the culling of adult and immature birds. This paper reports the findings of work carried out in 2013 at LGI.
For almost two decades Little Galloo Island (LGI)has supported the largest colony of double-crested cormorants ( Phalacrocorax auritus ) in the eastern basin of Lake Ontario. Cormorant nest counts on the island since the early 1990's have averaged about 5,000 per year reaching a high of 8,400 in 1996. Johnson et al. (2008) estimate that cormorants from LGI alone have consumed 400 million fish since 1992. The proliferation of cormorants in the eastern basin of Lake Ontario has coincided with declines in two important recreational fish species, smallmouth bass and yellow perch. Lantry et al. (2002) and Burnett et al. (2002) provide convincing evidence linking cormorant population increases to declining eastern basin smallmouth bass and yellow perch stocks. Decline of these fish stocks is evident only in the eastern basin, suggesting a localized problem which is consistent with the halo effect where large piscivorous waterbird colonies may deplete local fish stocks (Birt et al. 1987). The year 2008 marked the seventeenth consecutive year of study of the food habits and fish consumption of LGI cormorants, and represented the tenth consecutive year evaluating the efficacy of management activities to control the reproductive success of cormorants nesting at LGI. The program consists mainly of spraying cormorant eggs with oil as well as the culling of adult and immature birds.This paper reports the findings of work carried outin 2008 at LGI.
Explore the source record for details and available documents.
Flood-frequency analysis is based on records of annual maximum instantaneous flows observed at long-term streamgages with 10 years or more of operation. Since the last flood-frequency analysis in Nebraska, an additional 30 years of annual peak-flow data have become available, and new flood-frequency analysis techniques have been developed. Moreover, the Elkhorn River Basin in north-central and eastern Nebraska has experienced two of the three highest magnitude floods on record in 2010 and 2019. The U.S. Geological Survey, in cooperation with the Nebraska Department of Transportation, analyzed flow frequency at streamgages in the Elkhorn River Basin in Nebraska. Flow data from the U.S. Geological Survey and the Nebraska Department of Water, Energy, and Environment annual hydrographic reports were utilized to analyze peak flows. The Peak flow FreQuency (PeakFQ) software was used to perform a flood-frequency and nonstationarity analysis on the selected streamgages in the Elkhorn River Basin in Nebraska. Results of the peak-flow nonstationarity analysis indicate that, of the 23 streamgages analyzed for peak-flow frequency, 4 showed trends that were likely increasing for annual peak flows, whereas 3 indicated trends that were somewhat likely to be increasing. For 11 streamgages, the trend was categorized as about as likely as not, meaning there is less than a 70-percent chance of the trend being either upward or downward. Additionally, 2 streamgages exhibited trends that were somewhat likely to be decreasing, and 3 streamgages showed trends that were likely decreasing. Low-flow streamflows and nonstationarity in the Elkhorn River Basin were analyzed for low flow periods representing the 1-day, 7-day, and 30-day flows at 21 streamgages using the Hydrologic Toolbox software. Spatially, the nonstationarity analysis results indicated likely increasing or somewhat increasing trend likelihoods for the 1-day, 7-day, and 30-day low flows for many of the Elkhorn streamgages downstream from the Elkhorn River at Ewing, Nebr., streamgage (U.S. Geological Survey station 06797500) and on eastern tributaries during the period of record.
This report presents biomass-based summaries of fish communities in western Lake Erie derived from USGS bottom trawl surveys conducted from 2013 to 2023. Analyses herein evaluated trends in total biomass, abundance of dominant predator and forage species, non-native species composition, biodiversity and community structure. Data from this effort can be explored interactively online and are accessible for download. Annual survey data are added to these sources as data become available.
Much scientific research demonstrates the existence of recent climate variation, particularly global warming. Climate prediction models forecast that climate will change; it will become warmer, droughts will increase in number and severity, and extreme climate events will recur often—desiccating aridity, extremely wet, unusually warm, or even frigid at times. However, the global models apply to average conditions in large grids approximately 150 miles on an edge (Thorpe, 2005), and how or whether specific areas within a grid are affected is unclear. Flagstaff's climate is mentioned in the context of global change, but information is lacking on the amount and trend of changes in precipitation, snowfall, and temperature. The purpose of this report is to understand what may be happening to Flagstaff's climate by reviewing local climate history. Flagstaff is in north-central Arizona south of San Francisco Mountain, which reaches 12,633 feet, the highest in Arizona (fig. 1). At 6,900 feet, surrounded by ponderosa pine forest, Flagstaff enjoys a four-season climate; winter-daytime temperatures are cool, averaging 45 degrees (Fahrenheit). Summer-daytime temperatures are comfortable, averaging 80 degrees, which is pleasant compared with nearby low-elevation deserts. Flagstaff's precipitation averages 22-inches per year with a range of 9 to 39 inches. Snowfall occurs each season, averaging 97 inches annually. This report, written for the non-technical reader, interprets climate variation at Flagstaff as observed at the National Weather Service (NWS) station at Pulliam Field (or Airport), a first-order weather station staffed by meteorologists (Staudenmaier and others, 2007). The station is on a flat-topped ridge surrounded by forest 5-miles south of Flagstaff at an elevation of 7,003 feet. Data used in this analysis are daily measurements of precipitation (including snowfall) and temperature (maximum and minimum) covering the period from 1950, when the station began operation, through spring 2007. Conversations with Byron Peterson and Michael Staudenmaier of the NWS helped us understand the difficulties of collecting consistent weather data, operation of the station, and Flagstaff's climate. Weather is the daily or even instantaneous state of temperature and precipitation. Climate is the average or accumulation of these parameters over longer time scales such as a week, month, or year. Seasonal (winter, spring, summer, and fall) and annual averages of temperature and accumulated precipitation describe the temporal variation of Flagstaff's climate, which is shown graphically with time series (figs. 2, 4, 6, 8-15). These plots show precipitation or temperature on the ordinate plotted against time on the abscissa, which is a year for annually repeating data or the year of a particular season. The plots reveal changing patterns of precipitation and temperature related to droughts, wet episodes, and rising temperatures.
Water-quality and flow data from 31 sites in nontidal portions of the Chesapeake Bay Basin were analyzed to document annual nutrient and sediment loads and trends for the period 1985 through 1999 as part of an annual reevaluation and reporting for the Chesapeake Bay Program. Annual loads were estimated by use of the U.S. Geological Survey ESTIMATOR model. Trends were estimated using linear regression. Trends were reported for monthly mean flow, monthly load, flow-adjusted concentration, and flow-weighted concentration. Median yields and concentrations were calculated to help facilitate comparisons between basins. The drought of 1999 had pronounced effects on trend results. The trend in flow increased at 4 of the 31 sites, 8 fewer sites than in 1998. Ten less significant trends were estimated for nutrient and sediment loads compared to 1985-98. Trends in flow-weighted and flow-adjusted concentrations varied little by nutrient species and geographic location. Trends were generally downward or not significant for both the nitrogen and phosphorus species throughout the Chesapeake Bay Basin. Trends in flow-adjusted concentration indicated downward trends at most sites for nutrients and about half the sites for sediments, an indication that management actions are reducing nutrient and sediment concentrations.
Introduction This report primarily describes activities during Federal fiscal year (FY) 1997. During FY 1997, the USGS engaged in cooperative research projects, data collection, informal outreach, and work done under Memoranda of Understanding that related to American Indians or Alaska Natives. Some work was technical and/or research-oriented. Other work was educational. As much as possible, activities are listed from east to west and from north to south.
This report presents biomass-based summaries of fish communities in the West Basin of Lake Erie derived from USGS bottom trawl surveys conducted from 2013 to 2020 during June and September. The survey design provided temporal and spatial coverage that did not exist in the interagency trawl database, and thus complemented the August ODNR-OMNRF effort to reinforce stock assessments with more robust data. Analyses herein evaluated trends in: total biomass, abundance of dominant predator and forage species, non-native species composition, biodiversity and community structure. Data from this effort can be explored interactively online (https://lebs.shinyapps.io/western-basin/), and are accessible for download (https://www.sciencebase.gov/catalog/item/6013031fd34e162231fed756, Keretz et al. 2021). Annual survey data are added to these sources as the data become available.
An attempt will be made in the following paper to bring together, so far as is practicable, all that is known of the geology of the Philippine Islands. The report is intended as a vade mecum for geologists in the field and a guide to the literature in the office. Doubtless something has escaped which should have been included, especially among the shrewd remarks of early Spanish travelers, but research in that direction is curious rather than profitable. If here and there they caught a glimpse of truth, with which it would be pleasant to credit them, most of their views on geological matters were of a grotesque falsity, with which it would be unkind to reproach them.
Lake Erie has the most populated watershed of all the Great Lakes and has undergone dramatic anthropogenic changes. Since the 1800s, overexploitation of fish populations, habitat destruction, non-native species proliferation, industrial contamination, and changes in nutrient loading have impacted the fish community including declines in or extirpation of many native species (Regier et al. 1969, Hartman 1973; Leach & Nepszy 1976; Ludsin et al. 2001). Implementation of the Clean Water Act and Great Lakes Water Quality Agreement in the 1970s improved habitat conditions (Reutter 2019), which contributed to several strong percid year-classes (Vandergoot et al. 2019). These strong year-classes also benefited from more restrictive management practices that reduced harvest, ultimately rehabilitating Lake Erie percid stocks (Kayle et al. 2015, STC 2020). Historically, Lake Erie supported a cool water fish community dominated by percids and salmonids. Recently updated FCOs set forth a vision that “Lake Erie will consist of diverse fish communities that support ongoing societal benefits, including thriving commercial and recreational fisheries, improved fish habitat and desirable ecosystem performance, and reduced adverse impacts from invasive fish” (Francis et al. 2020). Today, mixed fisheries resulting from seasonally changing cool and warm water habitats have developed in Lake Erie, and the new FCOs reflect a desire to manage both predator and prey fish communities within them. Although Lake Erie management agencies have traditionally focused on numerical indices of a few economically important species, aquatic ecosystem models are typically evaluated in terms of entire fish community biomass. As a result, our understanding of fish community structure and ecosystem dynamics from biomass-based models has been limited to short-term investigations and proxy measurements (e.g., length-weight conversion; FTG 2020). Therefore, many Lake Erie fish community databases are now incorporating biomass-based measurements. In response, USGS revised the Lake Erie trawl program to provide biomass-based measurements for all encountered species (Table 1). The survey design change occurred in 2012, coincident with commissioning of a new research vessel and a change in bottom trawl gear. These modifications already altered the existing time series; therefore, the survey design was also expanded to include greater spatial coverage and increased sample size generating a new time series. The purpose of this report is to develop a comprehensive understanding of the long-term changes and fish community dynamics including population dynamics of key fishes of interest to management agencies, such as native percids and their prey. Here, we summarize survey results for the most recent series of West Basin trawl data from 2013 through 2025. Note that a detailed description of the sampling process along with traditional numericallybased catch data (e.g., fish/ha) for individual species can be downloaded online (DuFour et al. 2026) or obtained for earlier years (https://doi.org/10.5066/F75M63X0; U.S. Geological Survey, Great Lakes Science Center 2019).
SIR : In accordance with your instructions dated Washington, April 1, 1869, I have the honor to transmit my preliminary field report of the United States geological survey of Colorado and New Mexico, conducted by me, under your direction, during the past season. A portion of your instructions is as follows : “You will proceed to the field of your labors as soon as the necessary arrangements can be made and the season will permit, and your attention will be especially directed to the geological, mineralogical and agricultural resources of the Territories herein designated; you will be required to ascertain the age, order of succession, relative position, dip, and comparative thickness of the different strata and geological formations, and examine with care all the beds, veins, and other deposits, of ores, coals, clays, marls, peat, and other mineral substances, as well as the fossil remains of the different formations; and you will also make full collections in geology, mineralogy, and paleontology, to illustrate your notes taken in the field.”
An improved understanding of hydrologic responses to changing climatic conditions is needed to better inform water management practices. East Canyon Creek, a perennial, snowmelt-dominated stream in the Wasatch Mountains of northern Utah, is subjected to increasing development and demands on water in the Snyderville Basin and adjacent areas. In this study, streamflow and specific conductance measured at three U.S. Geological Survey streamgages on East Canyon Creek were used to estimate daily baseflow for water years 2011–22. Trends in these estimates and correlations with climate data from two Natural Resource Conservation Service snow telemetry (SNOTEL) stations within the Snyderville Basin above East Canyon Reservoir, were quantified and reported. Peak annual streamflow also was assessed for flood potential on the study reach of East Canyon Creek. The hydrograph separations showed consistent baseflow indices among all sites, with a larger baseflow component during the fall–spring period (September–April; baseflow indices approximately equal to [≈] 0.751–0.835) and smaller component during the summer period (May–August; baseflow indices ≈ 0.428–0.532). In-stream specific conductance during spring (February–April) was influenced by road salt application, limiting the utility of the hydrograph separation approach. Annual streamflow and climate data were evaluated for trends using the nonparametric Mann–Kendall test, with inconclusive results. Related tests for trends, the Seasonal and Regional Kendall tests, were used to evaluate data at monthly timesteps and indicated a decreasing trend in total streamflow and baseflow at all streamgages. The rank-based Kendall’s tau test for correlation was used to measure the ordinal association with climatic data at co-located SNOTEL stations. Total streamflow and baseflow were strongly correlated with precipitation and snow-water equivalent. By incorporating a predictive regression model, the nonparametric Theil–Sen line, these correlations could support the development of streamflow forecast models using climate data from SNOTEL stations. Such models would provide water managers with tools to help make proactive decisions, such as reservoir or water reclamation releases and curtailment of withdrawals, in response to regional drought or varying snowpack and spring runoff in a given year.