Skip to main content
U.S. flag

An official website of the United States government

Daniel L Calhoun

Intro:

My unofficial career with the USGS began in 1995 when I was “volunteered” to help USGS Hydrologic Technicians dig orifice lines and haul materials for new gage installations along Ichawaynochaway Creek in Southwest Georgia. I was working as a Hydrologic Technician for the Jones Ecological Research Center and had no idea what a couple days of Georgia Coastal Plain sweat would later bring. It was through this encounter that I was given an invitation to apply for an open student position (STEP in those days) with the USGS after starting graduate studies in Water Resources at the University of Georgia in 1998.  Upon completion of my degree, I converted to a Hydrologist position working with the Appalachicola-Chattahoochee-Flint Study Unit (ACFB) of the National Water Quality Assessment Program. Twenty plus years of employment have involved participation in and direction of multiple national and regional watershed and groundwater projects, amphibian research in the Southeast, liaison duties with the NPS during the Deep Water Horizon oil spill, many Regional Stream Quality Assessment tours of duty across the country, a wide assortment of scientific publications, and many other varied wonderful ways to make a living working for the USGS and DOI.  I now serve as an Assistant Director for Hydrologic Studies in Georgia for the South Atlantic Water Science Center and wouldn’t trade a minute of the time spent with the people with whom I have had the privilege of working.

Personnel of SAWSC

Science and Products

link
Sampling water for amphibian research

Amphibian Research and Monitoring Initiative (ARMI) - Southeast Region Water Quality

The U.S. Geological Survey's (USGS) Amphibian Research and Monitoring Initiative (ARMI) began in 2000 with the goal of determining the status and trends of amphibian populations throughout the U.S. The program was designed to provide information useful in determining causes of declines or other changes in population distributions. Personnel in the South Atlantic Water Science Center are...
By
South Atlantic Water Science Center (SAWSC)
link

Amphibian Research and Monitoring Initiative (ARMI) - Southeast Region Water Quality

The U.S. Geological Survey's (USGS) Amphibian Research and Monitoring Initiative (ARMI) began in 2000 with the goal of determining the status and trends of amphibian populations throughout the U.S. The program was designed to provide information useful in determining causes of declines or other changes in population distributions. Personnel in the South Atlantic Water Science Center are...
Learn More
link
USGS science for a changing world logo

Elucidating mechanisms underlying amphibian declines in North America using hierarchical spatial models

Amphibian populations are declining globally at unprecedented rates but statistically rigorous identification of mechanisms is lacking. Identification of reasons underlying large-scale declines is imperative to plan and implement effective conservation efforts. Most research on amphibian population decline has focused on local populations and local factors. However, the ubiquity of declines across
By
John Wesley Powell Center for Analysis and Synthesis
link

Elucidating mechanisms underlying amphibian declines in North America using hierarchical spatial models

Amphibian populations are declining globally at unprecedented rates but statistically rigorous identification of mechanisms is lacking. Identification of reasons underlying large-scale declines is imperative to plan and implement effective conservation efforts. Most research on amphibian population decline has focused on local populations and local factors. However, the ubiquity of declines across
Learn More
link
Need help? Contact us.

Contact the South Atlantic Water Science Center

Contact the South Atlantic Water Science Center:
By
South Atlantic Water Science Center (SAWSC)
link

Contact the South Atlantic Water Science Center

Contact the South Atlantic Water Science Center:
Learn More

Concentration of chemical constituents in lake sediments from selected coring locations on Lake Lanier, Georgia, May 2018

The data herein were collected in support of a larger study in Gwinnett County, Georgia, on the potential impacts of on-site waste water treatment (septic systems) on Lake Lanier water quality. Until recently, a missing component in this assessment was the inclusion of historical sediment and associated nutrient accumulation data from the lake to place results in a broader context. To this end, th
By
South Atlantic Water Science Center (SAWSC)

Data from a national survey for the amphibian chytrid fungus Batrachochytrium salamandrivorans

This dataset provides the results of a national survey of the conterminous U.S. for the salamander chytrid fungus Batrachochytrium salamandrivorans (Bsal) conducted by the U.S. Geological Survey Amphibian Research and Monitoring Initiative from May 2014 to August 2017. Sites were sampled by capturing amphibians by hand or by traps or nets that were then swabbed individually using methods that prev
By
Wetland and Aquatic Research Center

Water level data from select wetlands at Saint Marks National Wildlife Refuge:2010 - 2015

Small, seasonal pools and temporary ponds (
By
South Atlantic Water Science Center (SAWSC)
Filter Total Items: 19

Analysis of the herbicide diuron, three diuron degradates, and six neonicotinoid insecticides in water-Method details and application to two Georgia streams

A method for the determination of the widely used herbicide diuron, three degradates of diuron, and six neonicotinoid insecticides in environmental water samples is described. Filtered water samples were extracted by using solid-phase extraction (SPE) with no additional cleanup steps. Quantification of the pesticides from the extracted water samples was done by using liquid chromatography with tan
By
Water Resources, South Atlantic Water Science Center (SAWSC), California Water Science Center

Hydrologic and landscape database for the Cache and White River National Wildlife Refuges and contributing watersheds in Arkansas, Missouri, and Oklahoma

A hydrologic and landscape database was developed by the U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service, for the Cache River and White River National Wildlife Refuges and their contributing watersheds in Arkansas, Missouri, and Oklahoma. The database is composed of a set of ASCII files, Microsoft Access® files, Microsoft Excel® files, an Environmental Systems Resear
By
Water Resources, South Atlantic Water Science Center (SAWSC)

Contaminants in stream sediments from seven U.S. metropolitan areas: Data summary of a National Pilot Study

This report presents data collected as a part of a synoptic survey of stream sediment contaminants, associated watershed characteristics and invertebrate responses in laboratory sediment toxicity tests from 98 streams (sites) in seven metropolitan study areas across the continental United States. The report presents methods, data, and sediment-quality guidelines, including the derivation of a new
By
Water Resources, Washington Water Science Center, Columbia Environmental Research Center

Algal and Invertebrate Community Composition along Agricultural Gradients: A Comparative Study from Two Regions of the Eastern United States

Benthic algal and invertebrate communities in two Coastal Plain regions of the Eastern United States?the Delmarva Peninsula (27 sites) and Georgia Upper Coastal Plain (29 sites)?were assessed to determine if aspects of agricultural land use and nutrient conditions (dissolved and whole-water nitrogen and phosphorus) could be linked to biological community compositions. Extensive effort was made to
By
Water Resources, South Atlantic Water Science Center (SAWSC)

Chapter B. Physical, Chemical, and Biological Responses of Streams to Increasing Watershed Urbanization in the Piedmont Ecoregion of Georgia and Alabama, 2003

As part of the U.S. Geological Survey National Water-Quality Assessment Program?s effort to assess the physical, chemical, and biological responses of streams to urbanization, 30 wadable streams were sampled near Atlanta, Ga., during 2002?2003. Watersheds were selected to minimize natural factors such as geology, altitude, and climate while representing a range of urban development. A multimetric
By
Water Resources, South Atlantic Water Science Center (SAWSC)

Water quality and aquatic communities of upland wetlands, Cumberland Island National Seashore, Georgia, April 1999 to July 2000

Cumberland Island is the southernmost and largest barrier island along the coast of Georgia. The island contains about 2,500 acres of freshwater wetlands that are located in a variety of physical settings, have a wide range of hydroperiods, and are influenced to varying degrees by surface and ground water, rainwater, and seawater. In 1999-2000, the U.S. Geological Survey, in cooperation with the N
By
Water Resources, South Atlantic Water Science Center (SAWSC)

Occurrence of pesticides in water and sediment collected from amphibian habitats located throughout the United States, 2009-10

Water and bed-sediment samples were collected by the U.S. Geological Survey (USGS) in 2009 and 2010 from 11 sites within California and 18 sites total in Colorado, Georgia, Idaho, Louisiana, Maine, and Oregon, and were analyzed for a suite of pesticides by the USGS. Water samples and bed-sediment samples were collected from perennial or seasonal ponds located in amphibian habitats in conjunction w
By
Water Resources, California Water Science Center

Spatial and temporal assessment of back-barrier erosion on Cumberland Island National Seashore, Georgia, 2011–2013

Much research has been conducted to better understand erosion and accretion processes for the seaward zones of coastal barrier islands; however, at Cumberland Island National Seashore, Georgia, the greater management concern is the effect that erosion is having on the resources of the island’s western shoreline, or the back barrier. Catastrophic slumping and regular rates of erosion greater than 1
By
Water Resources, South Atlantic Water Science Center (SAWSC)

Quantifying climate sensitivity and climate-driven change in North American amphibian communities

Changing climate will impact species’ ranges only when environmental variability directly impacts the demography of local populations. However, measurement of demographic responses to climate change has largely been limited to single species and locations. Here we show that amphibian communities are responsive to climatic variability, using >500,000 time-series observations for 81 species across 8
By
Ecosystems, Water Resources, Wildlife Program, Eastern Ecological Science Center, Forest and Rangeland Ecosystem Science Center, Fort Collins Science Center, Northern Rocky Mountain Science Center, Patuxent Wildlife Research Center, South Atlantic Water Science Center (SAWSC), Southwest Biological Science Center, Upper Midwest Environmental Sciences Center, Western Ecological Research Center (WERC), Wetland and Aquatic Research Center , John Wesley Powell Center for Analysis and Synthesis

Pathogenic lineage of Perkinsea associated with mass mortality of frogs across the United States

Emerging infectious diseases such as chytridiomycosis and ranavirus infections are important contributors to the worldwide decline of amphibian populations. We reviewed data on 247 anuran mortality events in 43 States of the United States from 1999–2015. Our findings suggest that a severe infectious disease of tadpoles caused by a protist belonging to the phylum Perkinsea might represent the third
By
Ecosystems, National Wildlife Health Center, Wetland and Aquatic Research Center

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 landscap
By
Water Resources, South Atlantic Water Science Center (SAWSC)

Identifying small depressional wetlands and using a topographic position index to infer hydroperiod regimes for pond-breeding amphibians

Small, seasonal pools and temporary ponds (
By
Water Resources, South Atlantic Water Science Center (SAWSC), Wetland and Aquatic Research Center
link

Large-scale Review of Amphibian Species and Community Response to Climate Change

Amphibian species and community richness has been declining in North America and climate change may play a role in these declines. Global climate...

Read Article

Science and Products