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USGS2004

Water quality in the upper Illinois River basin: Illinois, Indiana, and Wisconsin, 1999-2001

This report contains the major findings of a 1999?2001 assessment of water quality in the upper Illinois River Basin. It is one of a series of reports by the National Water-Quality Assessment (NAWQA) Program that present major findings in 51 major river basins and aquifer systems across the Nation. In these reports, water quality is discussed in terms of local, State, and regional issues. Conditions in a particular basin or aquifer system are compared to conditions found elsewhere and to selected national benchmarks, such as those for drinking-water quality and the protection of aquatic organisms. This report is intended for individuals working with water-resource issues in Federal, State, or local agencies, universities, public-interest groups, or in the private sector. The information will be useful in addressing a number of current issues, such as the effects of agricultural and urban land use on water quality, human health, drinking water, source-water protection, hypoxia and excessive growth of algae and plants, pesticide registration, and monitoring and sampling strategies. This report also is for individuals who wish to know more about the quality of streams and ground water in areas near where they live, and how that water quality compares to the quality of water in other areas across the Nation. The water-quality conditions in the upper Illinois River Basin summarized in this report are discussed in detail in other reports that can be accessed from (http://il.water.usgs.gov/nawqa/uirb). Detailed technical information, data and analyses, collection and analytical methodology, models, graphs, and maps that support the findings presented in this report in addition to reports in this series from other basins can be accessed from the national NAWQA Web site at (http://water.usgs.gov/nawqa).

Illinois, Indiana, and Wisconsin↗

USGS2004

Water quality in the Mobile River Basin, Alabama, Georgia, Mississippi, and Tennessee, 1999-2001

This report contains the major findings of a 1999?2001 assessment of water quality in the Mobile River Basin. It is one of a series of reports by the National Water-Quality Assessment (NAWQA) Program that present major findings in 51 major river basins and aquifer systems across the Nation. In these reports, water quality is discussed in terms of local, State, and regional issues. Conditions in a particular basin or aquifer system are compared to conditions found elsewhere and to selected national benchmarks, such as those for drinking-water quality and the protection of aquatic organisms. This report is intended for individuals working with water-resource issues in Federal, State, or local agencies, universities, public interest groups, or in the private sector. The information will be useful in addressing a number of current issues, such as the effects of agricultural and urban land use on water quality, human health, drinking water, source-water protection, hypoxia and excessive growth of algae and plants, pesticide registration, and monitoring and sampling strategies. This report is also for individuals who wish to know more about the quality of streams and ground water in areas near where they live, and how that water quality compares to the quality of water in other areas across the Nation. The water-quality conditions in the Mobile River Basin summarized in this report are discussed in detail in other reports that can be accessed from the Mobile River Basin Web site (http://al.water.usgs.gov/pubs/mobl/mobl.html). Detailed technical information, data and analyses, collection and analytical methodology, models, graphs, and maps that support the findings presented in this report in addition to reports in this series from other basins can be accessed from the national NAWQA Web site (http://water.usgs.gov/nawqa).

Alabama, Georgia, Mississippi, Tennessee↗

USGS2004

Water quality in the Acadian-Pontchartrain drainages: Louisiana and Mississippi, 1999–2001

This report contains the major findings of a 1999-2001 assessment of water quality in the Acadian-Pontchartrain Drainages Study Unit. It is one of a series of reports by the National Water-Quality Assessment (NAWQA) Program that present major findings in 51 major river basins and aquifer systems across the Nation. In these reports, water quality is discussed in terms of local, State, and regional issues. Conditions in a particular basin or aquifer system are compared to conditions found elsewhere and to selected national benchmarks, such as those for drinking-water quality and the protection of aquatic organisms. This report is intended for individuals working with water-resource issues in Federal, State, or local agencies, universities, public interest groups, or in the private sector. The information will be useful in addressing a number of current issues, such as the effects of agricultural and urban land use on water quality, human health, drinking water, source-water protection, hypoxia and excessive growth of algae and plants, pesticide registration, and monitoring and sampling strategies. This report also is for individuals who wish to know more about the quality of streams and ground water in areas near where they live, and how that water quality compares to other areas across the Nation. The water-quality conditions in the Acadian-Pontchartrain Drainages Study Unit summarized in this report are discussed in detail in other reports that can be accessed from (http://la.water.usgs.gov/nawqa/default.htm). Detailed technical information, data and analyses, collection and analytical methodology, models, graphs, and maps that support the findings presented in this report in addition to other reports in this series from other basins can be accessed from the national NAWQA Web site (http://water.usgs.gov/nawqa).

Louisiana, Mississippi↗

USGS2004

Water quality in the lower Tennessee River Basin, Tennessee, Alabama, Kentucky, Mississippi, and Georgia, 1999-2001

This report contains the major findings of a 1999?2001 assessment of water quality in the Lower Tennessee River Basin. It is one of a series of reports by the National Water-Quality Assessment (NAWQA) Program that present major findings in 51 major river basins and aquifer systems across the Nation. In these reports, water quality is discussed in terms of local, State, and regional issues. Conditions in a particular basin or aquifer system are compared to conditions found elsewhere and to selected national benchmarks, such as those for drinking-water quality and the protection of aquatic organisms. This report is intended for individuals working with water-resource issues in Federal, State, or local agencies, universities, public interest groups, or in the private sector. The information will be useful in addressing a number of current issues, such as the effects of agricultural and urban land use on water quality, human health, drinking water, source-water protection, hypoxia and excessive growth of algae and plants, pesticide registration, and monitoring and sampling strategies. This report is also for individuals who wish to know more about the quality of streams and ground water in areas where they live, and how that water quality compares to the quality of water in other areas across the Nation. The water-quality conditions in the Lower Tennessee River Basin summarized in this report are discussed in detail in other reports that can be accessed from the Lower Tennessee River Basin Web site (http://tn.water.usgs.gov/lten/lten.html). Detailed technical information, data and analyses, collection and analytical methodology, models, graphs, and maps that support the findings presented in this report in addition to reports in this series from other basins can be accessed from the national NAWQA Web site (http://water.usgs.gov/nawqa).

Alabama, Georgia, Kentucky, Mississippi, Tennessee↗

USGS2004

Water quality in the Yellowstone River Basin, Wyoming, Montana, and North Dakota, 1999-2001

This report contains the major findings of a 1999?2001 assessment of water quality in the Yellowstone River Basin. It is one of a series of reports by the National Water-Quality Assessment (NAWQA) Program that present major findings in 51 major river basins and aquifer systems across the Nation. In these reports, water quality is discussed in terms of local, State, and regional issues. Conditions in a particular basin or aquifer system are compared to conditions found elsewhere and to selected national benchmarks, such as those for drinking-water quality and the protection of aquatic organisms. This report is intended for individuals working with water-resource issues in Federal, State, or local agencies, universities, public interest groups, or in the private sector. The information will be useful in addressing a number of current issues, such as the effects of agricultural and urban land use on water quality, human health, drinking water, source-water protection, hypoxia and excessive growth of algae and plants, pesticide registration, and monitoring and sampling strategies. This report also is for individuals who wish to know more about the quality of streams and ground water in areas near where they live, and how that water quality compares to the quality of water in other areas across the Nation. The water-quality conditions in the Yellowstone River Basin summarized in this report are discussed in detail in other reports that can be accessed from http://wy.water.usgs.gov/YELL/index.htm. Detailed technical information, data and analyses, collection and analytical methodology, models, graphs, and maps that support the findings presented in this report, in addition to reports in this series from other basins, can be accessed from the national NAWQA Web site (http://water.usgs.gov/nawqa).

Circular↗

USGS2003

Water quality in the Northern Rockies Intermontane basins, Idaho, Montana, and Washington, 1999-2001

This report contains the major findings of a 1999–2001 assessment of water quality in the Northern Rockies Intermontane Basins. It is one of a series of reports by the National Water-Quality Assessment (NAWQA) Program that present major findings in 51 major river basins and aquifer systems across the Nation. In these reports, water quality is discussed in terms of local, State, and regional issues. Conditions in a particular basin or aquifer system are compared to conditions found elsewhere and to selected national benchmarks, such as those for drinking-water quality and the protection of aquatic organisms. This report is intended for individuals working with water-resource issues in Federal, State, or local agencies, universities, public interest groups, or in the private sector. The information will be useful in addressing a number of current issues, such as the effects of agricultural and urban land use on water quality, human health, drinking water, source-water protection, hypoxia and excessive growth of algae and plants, pesticide registration, and monitoring and sampling strategies. This report is also for individuals who wish to know more about the quality of streams and ground water in areas near where they live, and how that water quality compares to the quality of water in other areas across the Nation. The water-quality conditions in the Northern Rockies Intermontane Basins summarized in this report are discussed in detail in other reports that can be accessed from (http://id.water.usgs.gov/nrok/index.html). Detailed technical information, data and analyses, collection and analytical methodology, models, graphs, and maps that support the findings presented in this report in addition to reports in this series from other basins can be accessed from the national NAWQA Web site (http://water.usgs.gov/nawqa).

Idaho;Montana;Washington↗

USGS2004

Water Quality in the Great Salt Lake Basins, Utah, Idaho, and Wyoming, 1998-2001

This report contains the major findings of a 1998-2001 assessment of water quality in the Great Salt Lake Basins. It is one of a series of reports by the National Water-Quality Assessment (NAWQA) Program that present major findings in 51 major river basins and aquifer systems across the Nation. In these reports, water quality is discussed in terms of local, State, and regional issues. Conditions in a particular basin or aquifer system are compared to conditions found elsewhere and to selected national benchmarks, such as those for drinking-water quality and the protection of aquatic organisms. This report is intended for individuals working with water-resource issues in Federal, State, or local agencies, universities, public interest groups, or in the private sector. The information will be useful in addressing a number of current issues, such as the effects of agricultural and urban land use on water quality, human health, drinking water, source-water protection, hypoxia and excessive growth of algae and plants, pesticide registration, and monitoring and sampling strategies. This report is also for individuals who wish to know more about the quality of streams and ground water in areas near where they live, and how that water quality compares to water quality in other areas across the Nation. The water-quality conditions in the Great Salt Lake Basins summarized in this report are discussed in detail in other reports that can be accessed at http://ut.water.usgs.gov. Detailed technical information, data and analyses, collection and analytical methodology, models, graphs, and maps that support the findings presented in this report in addition to reports in this series from other basins can be accessed at the national NAWQA Web site http://water.usgs.gov/nawqa.

Circular↗

USGS2004

Water quality in the Santa Ana Basin, California, 1999-2001

This report contains the major findings of a 1999-2001 assessment of water quality in the Santa Ana River Basin. It is one of a series of reports by the National Water-Quality Assessment (NAWQA) Program that present major findings in 51 major river basins and aquifer systems across the Nation. In these reports, water quality is discussed in terms of local, State, and regional issues. Conditions in a particular basin or aquifer system are compared to conditions found elsewhere and to selected national benchmarks, such as those for drinking-water quality and the protection of aquatic organisms. This report is intended for individuals working with water-resource issues in Federal, State, or local agencies, universities, public interest groups, or in the private sector. The information will be useful in addressing a number of current issues, such as the effects of agricultural and urban land use on water quality, human health, drinking water, source-water protection, hypoxia and excessive growth of algae and plants, pesticide registration, and monitoring and sampling strategies. This report is also for individuals who wish to know more about the quality of streams and ground water in areas near where they live and how that water quality compares to other areas across the Nation. The water-quality conditions in the Santa Ana River Basin summarized in this report are discussed in detail in other reports that can be accessed from http://ca.water.usgs.gov/ sana_nawqa/. Detailed technical information, data and analyses, collection and analytical methodology, models, graphs, and maps that support the findings presented in this report in addition to other reports in this series from other basins can be accessed from the national NAWQA Web site (http://water.usgs.gov/nawqa).

Circular↗

USGS2013

Five-year interim report of the United States-Mexico Transboundary Aquifer Assessment Program: 2007--2012

Transboundary aquifers are an essential, and in many cases, singular source of water for United States – Mexico border communities, particularly in arid regions. Declining water levels, deteriorating water quality, and increasing use of groundwater resources by municipal, industrial, and agricultural water users on both sides of the international border have raised concerns about the long-term availability of this supply. Water quantity and quality are determining and limiting factors that ultimately control agriculture, future economic development, population growth, human health, and ecological conditions along the border. Knowledge about the extent, depletion rates, and quality of transboundary aquifers, however, is limited and, in some areas, completely absent. The U.S. – Mexico Transboundary Aquifer Assessment Act (Public Law 109-448), referred to in this report as “the Act,” was signed into law by the President of the United States on December 22, 2006, to conduct binational scientific research to systematically assess priority transboundary aquifers and to address water information needs of border communities. The Act authorizes the Secretary of the Interior, through the U.S. Geological Survey (USGS), to collaborate with the States of Arizona, New Mexico, and Texas through their Water Resources Research Institutes (WRRIs) and with the International Boundary and Water Commission (IBWC), stakeholders, and Mexican counterparts to provide new information and a scientific foundation for State and local officials to address pressing water-resource challenges along the U.S. – Mexico border.

Open-File Report↗

USGS2020

Forest management and bats

Because more than half of the forest land in the United States is privately owned, forest landowners play an important role in the stewardship of our wildlife resources. This publication will introduce you to a group of wildlife that is particularly important to forest ecosystems, but also one of the most misunderstood: bats. We will demonstrate how active forest management can improve forest health and productivity while maintaining and enhancing habitat for these fascinating and beneficial mammals.

Report↗

USGS2010

Harmful algal blooms: A case study in two mesotrophic drinking water supply reservoirs in South Carolina

Algal blooms can be harmful and a nuisance in a variety of aquatic ecosystems, including reservoirs and lakes. Cyanobacterial(blue-green algae) harmful algal blooms are notorious for producing both taste-and-odor compounds and potent toxins that may affect human health. Taste–and-odor episodes are aesthetic problems often caused by cyanobacterial-produced organic compounds (geosmin and methylisoborneol) and are common in reservoirs and lakes used as source water supplies. The occurrences of these taste-and-odor compounds and toxins (like microcystin) can be sporadic and vary in intensity both spatially and temporally. Recent publications by the U.S. Geological Survey address this complexity and provide protocols for cyanotoxin and taste-and-odor sampling programs. A case study conducted by the U.S. Geological Survey, in cooperation with Spartanburg Water, monitored two mesotrophic reservoirs that serve as public drinking water supplies in South Carolina. Study objectives were (1) to identify spatial and temporal occurrence of the taste-and-odor compound geosmin and the cyanotoxin microcystin and (2) to assess the associated limnological conditions before, during, and after these occurrences. Temporal and spatial occurrence of geosmin and microcystin were highly variable from 2007 to 2009. The highest geosmin concentrations tended to occur in the spring. Microcystin tended to occur in the late summer and early fall, but occurrence was rare and well below World Health Organization guidelines for finished drinking water and recreational activities. No current U.S. Environmental Protection Agency standards are applicable to cyanotoxins in drinking or ambient water. In general, elevated geosmin and microcystin concentrations were the result of complex interactions between cyanobacterial community composition, nutrient availability, water clarity, hydraulic residence time, and stratification.

South Carolina↗

USGS2024

Results of 2018–19 water-quality and hydraulic characterization of aquifer intervals using packer tests and preliminary geophysical-log correlations for selected boreholes at and near the former Naval Air Warfare Center Warminster, Bucks County, Pennsylvania

The U.S. Geological Survey (USGS) collected data on the vertical distribution of hydraulic head, specific capacity, and water quality using aquifer-interval-isolation tests and other vertical profiling methods in 15 boreholes completed in fractured sedimentary bedrock in Northampton, Warminster, and Warwick Townships, Bucks County, Pennsylvania during 2018–19. This work was done, in cooperation with the U.S. Navy, to support detailed investigations at and near the former Naval Air Warfare Center (NAWC) Warminster, where groundwater contamination with per- and polyfluoroalkyl substances (PFAS) had become a concern since 2014. Two PFAS compounds, perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), have been measured in groundwater samples from supply and monitoring wells at or near NAWC Warminster in concentrations above U.S. Environmental Protection Agency health advisory levels for drinking water. The area is underlain by the Triassic Stockton Formation, which predominantly consists of sandstone interbedded with shale and siltstone beds and forms a layered fractured-rock aquifer used for private, industrial, and public drinking water supply. The vertical distribution of aquifer properties and water quality was assessed through hydraulic tests and sampling of aquifer intervals using a straddle-packer system (13 boreholes) or depth-discrete point sampling under known borehole-flow conditions (2 boreholes). Geophysical and video logs collected by USGS during 2017–19 were used to identify potential water-bearing fractures in 15 boreholes, which ranged in depth from 210 to 604 feet (ft) and included 6 boreholes drilled in 2018 and 9 existing wells on or near the former NAWC Warminster. Measured borehole flow was predominantly downward in most of the deepest boreholes (greater than 400 ft), which were commonly located at the highest land-surface elevations, with inflow from fractures at relatively shallow depths and outflow through fractures near or below depths of 500 ft below land surface. Hydraulic head differences measured during packer tests were up to about 60 ft between shallow and deep intervals. Borehole flow was predominantly upward in most boreholes less than 400 ft in depth and farther from, and at lower land-surface elevations than, the former NAWC Warminster. Total borehole specific capacity ranged from about 0.07 to 41 gallons per minute per foot [(gal/min)/ft]. Specific-capacity values for individual intervals ranged from 0.02 to 40.0 (gal/min)/ft, with a median of 1.14 (gal/min)/ft and a large range in values at most depths. Differences in water quality of samples as indicated by field properties (pH, dissolved oxygen, and specific conductance) and concentrations of dissolved major ions, PFOA, and PFOS were apparent among isolated intervals in the boreholes. Summed concentrations of PFOA and PFOS ranged from about 11 to 10,780 nanograms per liter (ng/L) and were greater than the 2016 U.S. Environmental Protection Agency health advisory of 70 ng/L for summed PFOA and PFOS concentrations in 62 of 104 intervals and discrete depths tested. The mass ratio of PFOS to PFOA was generally higher than 1.0 in samples with summed PFOA and PFOS concentrations greater than 70 ng/L, with ratio values as high as 8.7. In many boreholes, summed concentrations of PFOA and PFOS were positively related to chloride concentrations, which were elevated above natural-background values [less than 10 milligrams per liter] in most samples and as high as 717 milligrams per liter. Sources of the elevated chloride other than, or in addition to, common rock salt (sodium chloride) were indicated by chloride to sodium molar ratios greater than 1.0. Water-quality data indicated that sampled water from some intervals with lower hydraulic heads may be affected by water from intervals with higher hydraulic heads because of vertical flow in open boreholes; samples from these intervals with lower hydraulic heads may not be fully representative due to some component of cross contamination and should be interpreted with caution. Through a preliminary correlation of natural gamma and resistivity logs of boreholes drilled at and near the former NAWC Warminster, 11 lithologic units were identified and interpreted to strike northeast and dip to the northwest. Hydraulic heads were generally highest in isolated intervals that intercepted beds which, when projected up dip, crop out at the highest land-surface elevation on the former NAWC Warminster, indicating that the dipping-bed structure and topography are factors affecting the distribution of hydraulic head in the aquifer. The hydrogeologic framework in conjunction with the vertical distribution of hydraulic heads and water quality may assist in evaluating the locations of various PFAS sources and potential migration pathways of PFAS in groundwater at and near NAWC Warminster.

Pennsylvania↗

USGS2020

The relation of geogenic contaminants to groundwater age, aquifer hydrologic position, water type, and redox conditions in Atlantic and Gulf Coastal Plain aquifers, eastern and south-central USA

Groundwater age distributions developed from carbon-14 (14C), tritium (3H), and helium-4 (4He) concentrations, along with aquifer hydrologic position, water type, and redox conditions, were compared to geogenic contaminants of concern (GCOC) from 252 public-supply wells in six Atlantic and Gulf Coastal Plain unconsolidated-sediment aquifers. Concentrations of one or more GCOCs in 168 (67%) wells exceeded MCLs (maximum contaminant levels), SMCLs (secondary MCLs), or HBSLs (health-based screening levels). Human-health benchmark thresholds (MCLs or HBSLs) were exceeded in 31 (12%) wells, and included 0.8% for fluoride (F), 2.4% for arsenic (As), 4% for lead-210 (210Pb), and 4.8% for polonium-210 (210Po). Values of pH increase with age and were outside the SMCL in 31% of wells (23% < 6.5 and 7.5% > 8.5, SMCL). Among GCOCs with concentrations that increased significantly with groundwater age, the frequency of sentry threshold exceedances (i.e., one-half of MCL, SMCL, or HBSL) included 40% for dissolved solids (DS), 12% for chloride (Cl), 3.6% for F, 4.4% for As, and 9.1% for 210Po. Iron (Fe) concentrations did not correlate with groundwater age but exceeded sentry thresholds in 29% of wells. Groundwater age, water types, redox, pH, and GCOCs varied because of unique hydrogeologic features of the aquifers (recharge locations and geometry). As expected, primarily confined aquifers had young, oxic, low to near-neutral pH water near the outcrop (recharge area), and older, reduced, high pH water deeper and farther along flow paths. However, unique aquifer hydrogeologic conditions, such as multiple-recharge zones produced anomalous patterns of young and old groundwater at varying depths and locations along flow paths. Evidence for this variability is seen in disequilibrium patterns in the progression of the chemical evolution of groundwater with hydrologic position. When hydrogeologic differences are considered, groundwater age combined with hydrologic-position data, can provide a strong basis for inferring potential occurrence of GCOCs.

Gulf Coastal Plain aquifers↗

USGS2014

USGS investigations of water produced during hydrocarbon reservoir development

Significant quantities of water are present in hydrocarbon reservoirs. When brought to the land surface during oil, gas, and coalbed methane production, the water—either naturally occurring or injected as a method to enhance production—is termed produced water. Produced water is currently managed through processes such as recycling, treatment and discharge, spreading on roads, evaporation or infiltration, and deep well injection. U.S. Geological Survey (USGS) scientists conduct research and publish data related to produced water, thus providing information and insight to scientists, decisionmakers, the energy industry, and the public. The information advances scientific knowledge, informs resource management decisions, and facilitates environmental protection. This fact sheet discusses integrated research being conducted by USGS scientists supported by programs in the Energy and Minerals and Environmental Health Mission Areas. The research products help inform decisions pertaining to understanding the nature and management of produced water in the United States.

Fact Sheet↗

USGS2020

PFAS in the environment

The U.S. Geological Survey (USGS) is working with Federal, State, and local partners to monitor and evaluate perfluoroalkyl and polyfluoroalkyl substances (PFAS) in the State’s groundwater and surface waters. PFAS are synthetic chemicals with widespread commercial and industrial use that can take a very long time to break down in the environment and may affect human health. The USGS in New York is working with experts across the Nation to develop and implement rigorous and innovative techniques to detect PFAS at concentrations as low as parts per trillion to help the public understand the spatial distribution and magnitude of PFAS contamination within the environment.

General Information Product↗

USGS2020

Monitoring and real-time modeling of Escherichia coli bacteria for the Chattahoochee River, Chattahoochee River National Recreation Area, Georgia, 2000–2019

The Chattahoochee River National Recreation Area (CRNRA) is a National Park Service unit/park with 48 miles of urban waterway in the Atlanta metropolitan area. The Chattahoochee River within the CRNRA is a popular place for water-based recreation but is known to periodically experience elevated levels of fecal-coliform bacteria associated with warm-blooded animals that can result in a variety of pathogen-related human illnesses. In 2000, the National Park Service entered into a public-private partnership with the U.S. Geological Survey (USGS) and the Chattahoochee Riverkeeper, called the Chattahoochee River BacteriALERT program, to monitor Escherichia coli ( E. coli ), which is a fecal indicator bacteria and a proxy for human health risk from waterborne pathogens. The BacteriALERT network monitors E. coli densities at three stations on the Chattahoochee River within the CRNRA, at Norcross (USGS station 02335000), Powers Ferry (USGS station 02335880), and Atlanta (USGS station 02336000). E. coli densities determined from water samples were compared to the U.S. Environmental Protection Agency’s Beach Action Value (BAV) of 235 colony forming units per 100 milliliters to assess whether conditions were considered safe for freshwater, primary contact recreational use. Sample E. coli densities exceeded the BAV for 15.5 percent of the samples collected at Norcross (n = 1,969) and 30.3 percent of the samples at Atlanta (n = 1,938) for the study period October 23, 2000, to May 23, 2019, and 33.6 percent of the samples from Powers Ferry (n = 134) for the study period May 5, 2016, to May 23, 2019. Models to predict E. coli densities in near real-time were developed for the three BacteriALERT stations. Models were developed using forward-stepwise multiple linear regression with the Bayesian Information Criteria and were calibrated with samples collected between October 4, 2007, and May 23, 2019. Explanatory variables included season, turbidity, water temperature, streamflow, upstream tributary streamflows, and temporal trend. The most statistically significant explanatory variables in the models were turbidity, upstream tributary streamflows, and season. The Norcross model had an increasing trend in E. coli densities of 2.3 percent per year. A significant trend was not detected for the Atlanta station, while trends were not assessed for Powers Ferry models due to the short (3-year) calibration period. Model adjusted R 2 s ranged from 0.686 (Atlanta) to 0.795 (Norcross with time trend) indicating that the models explained a substantial portion of the variations in E. coli densities. Evaluation of model predictions and residuals indicated that models were well posed and exhibited little bias. The models performed well in accurately determining compliance and exceedance of the BAV with low misidentification rates ranging from 3.5 percent (Norcross) to 11.3 percent (Powers Ferry). Misidentification was most common for densities near the BAV, and misidentification rates in the study were low despite fairly low model precisions because E. coli densities were infrequently near the BAV. The precisions of the models developed herein were comparable to the more complex models developed by Lawrence (2012) that were never implemented in the BacteriALERT program due to their computational complexity. The predictive E. coli models developed herein will improve the ability to assess the health risks of water-based recreational activities in the CRNRA in near real-time.

Georgia↗

USGS2004

Historical perspectives on the concept of ecosystem degradation

The concept of environmental degradation has evolved with the development of human society and settlement. In early human development, tribes went through a series of cycles of taming or developing mastery over the environment, to utilizing the resources of that environment until they could no longer support the population, which lead to moving on to do it again in a new area. There seems to have been little sense that human activity was causing any degradation, it was only that there was no longer enough food. This sense of the concept of degradation can even be seen as late as the 16th and 17th centuries in North America as Europeans "tamed" the land from the south, east, and north. For the Europeans, this taming of the "dangerous" and "inhospitable" lands even included the indigenous peoples. World-wide, as humans gathered into towns and cities, the impacts on the environment became increasingly widespread. Goods had to be brought to the people from further and further away. While agriculture and herd management were being developed, there was still the sense that these activities were improvements. It is a rather modern social understanding that human activities can and do damage and degrade natural ecosystems. The concept began to dawn when society began to understand that some activities caused degraded human health. Only recently has society begun to understand the need for generally healthy natural ecosystems and this understanding has brought with it a whole host of legal and political actions to make it happpen. ?? International Scientific Publications, New Delhi.

Conference Paper↗

USGS1998

Reduction of earthquake risk in the United States: Bridging the gap between research and practice

Continuing efforts under the auspices of the National Earthquake Hazards Reduction Program are under way to improve earthquake risk assessment and risk management in earthquake-prone regions of Alaska, California, Nevada, Washington, Oregon, Arizona, Utah, Wyoming, and Idaho, the New Madrid and Wabash Valley seismic zones in the central United States, the southeastern and northeastern United States, Puerto Rico, Virgin Islands, Guam, and Hawaii. Geologists, geophysicists, seismologists, architects, engineers, urban planners, emergency managers, health care specialists, and policymakers are having to work at the margins of their disciplines to bridge the gap between research and practice and to provide a social, technical, administrative, political, legal, and economic basis for changing public policies and professional practices in communities where the earthquake risk is unacceptable.

IEEE Transactions on Engineering Management↗