My research interests are in watershed biogeochemical processes, specifically in identifying the hydrologic and anthropogenic drivers of those processes. My research focuses on the status and trends of stream flow and stream-water quality in response to stressors, including air pollution, climatic variability, and anthropogenic land-use influences.
Recent highlights of the impact of my science on society include invited speaking engagements at the Cosmos Club for the Geological Society of Washington, D.C.; a NASA-sponsored public panel discussion in Boulder, Co., along with Jim Hansen, Brian Toon, and Bill Nye (the Science Guy); multiple National Public Radio interviews and broadcasts; and news coverage in The Washington Post, The Baltimore Sun, USA Today, and the Natural Resources Defense Council.
Most of my research has been published in Environmental Science & Technology and Water Resources Research, but other outlets include Applied Geochemistry, Annual Review of Earth and Planetary Sciences, Atmospheric Environment, Chemical Geology, Climatic Change, Earth Surface Processes and Landforms, Hydrological Processes, and Journal of Hydrology.
I hold a joint appointment as Research Hydrologist with USGS and Research Faculty in the Department of Environmental Sciences at University of Virginia.
Education and Certifications
B.S. in Geology from James Madison University
M.S. in Geology from Utah State University
Ph.D. in Environmental Sciences from the University of Virginia
Science and Products
Climate Change in the Chesapeake Bay Watershed: Effects on Riverine Discharge, Ecosystems, and Water Quality
Appalachian Trail MEGA-Transect Atmospheric Deposition Effects Study
Science Summary-Stream temperature rising throughout the Chesapeake Bay region
Groundwater hydrology and chemistry of Jamestown Island, Virginia—Potential effects of tides, storm surges, and sea-level rise on archaeological, cultural, and ecological resources
Chemical constituent concentrations in stream water, streambed sediment, and soils of Fort Belvoir, Virginia—A characterization of ambient conditions in 2019
Chronic and episodic acidification of streams along the Appalachian Trail corridor, eastern United States
Riverine discharges to Chesapeake Bay: Analysis of long-term (1927–2014) records and implications for future flows in the Chesapeake Bay basin
Acid Rain
Transmission of atmospherically deposited trace elements through an undeveloped, forested Maryland watershed
Geology-based method of assessing sensitivity of streams to acidic deposition in Charles and Anne Arundel Counties, Maryland
Mystery solved: White deposit on streambeds proves to be diatoms
Assessment of salinity intrusion in the James and Chickahominy Rivers as a result of simulated sea-level rise in Chesapeake Bay, East Coast, USA
Comparison of mineral weathering and biomass nutrient uptake in two small forested watersheds underlain by quartzite bedrock, Catoctin Mountain, Maryland, USA
Reply to comment on “Anthropogenic sources of arsenic and copper to sediments in a suburban lake, northern Virginia"
Fort Belvoir, Virginia, stream-water, streambed-sediment, and soil data collected in 2019
Science and Products
- Science
Climate Change in the Chesapeake Bay Watershed: Effects on Riverine Discharge, Ecosystems, and Water Quality
The 64,000-square mile watershed that drains to the Chesapeake Bay is highly populated and has diverse land use, including forested, agricultural, and urbanized areas. Increased precipitation in the eastern United States over the last 100 years has affected stream flow and thus the loading of pollutants delivered to the bay. Such pollutants as suspended sediment and dissolved phosphorus and...Appalachian Trail MEGA-Transect Atmospheric Deposition Effects Study
The Appalachian Trail (AT), a 14-state footpath from Maine to Georgia, is a unit of the National Park Service that is cooperatively managed and maintained by the National Park Service (NPS), the Appalachian Trail Conservancy, AT Club volunteers, the USDA Forest Service, and other public land-management agencies. Upper elevation and ridge-top ecosystems, which comprise much of the trail corridoScience Summary-Stream temperature rising throughout the Chesapeake Bay region
U.S. Geological Survey research, published in the journal Climatic Change - Publications
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Groundwater hydrology and chemistry of Jamestown Island, Virginia—Potential effects of tides, storm surges, and sea-level rise on archaeological, cultural, and ecological resources
As the site of the first permanent English settlement in North America in 1607, Jamestown Island, Colonial National Historical Park (COLO), Virginia, contains a rich archaeological record that extends from the Paleoindian period (15,000 to 8,000 years ago) through the 20th century. The island is located on the lower James River near the mouth of Chesapeake Bay. Jamestown Island vegetation is dominChemical constituent concentrations in stream water, streambed sediment, and soils of Fort Belvoir, Virginia—A characterization of ambient conditions in 2019
IntroductionThe U.S. Army Fort Belvoir (FTBL) installation is on the banks of the Potomac River in Fairfax County, northeastern Virginia. The installation was founded by the U.S. Army during World War I. It has been home to a variety of military organizations over the course of its more than 100-year history and currently houses more than 145 mission partners. The installation consists of two noncChronic and episodic acidification of streams along the Appalachian Trail corridor, eastern United States
Acidic atmospheric deposition has adversely affected aquatic ecosystems globally. As emissions and deposition of sulfur (S) and nitrogen (N) have declined in recent decades across North America and Europe, ecosystem recovery is evident in many surface waters. However, persistent chronic and episodic acidification remain important concerns in vulnerable regions. We evaluated acidification in 269 heRiverine discharges to Chesapeake Bay: Analysis of long-term (1927–2014) records and implications for future flows in the Chesapeake Bay basin
The Chesapeake Bay (CB) basin is under a total maximum daily load (TMDL) mandate to reduce nitrogen, phosphorus, and sediment loads to the bay. Identifying shifts in the hydro-climatic regime may help explain observed trends in water quality. To identify potential shifts, hydrologic data (1927–2014) for 27 watersheds in the CB basin were analyzed to determine the relationships among long-term precAcid Rain
Although acid rain is fading as a political issue in the United States and funds for research in this area have largely disappeared, the acidity of rain in the Eastern United States has not changed significantly over the last decade, and it continues to be a serious environmental problem. Acid deposition (commonly called acid rain) is a term applied to all forms of atmospheric deposition of acidicTransmission of atmospherically deposited trace elements through an undeveloped, forested Maryland watershed
Retention and transmission of atmospherically-derived major (H+, Na+, K+, Ca2+, Mg2+, HCO3-, NO3-, SO4-2, Cl-, SiO2) and trace (Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Se, and Zn) species were evaluated in an undeveloped forested watershed underlain by a rather inert quartzite lithology (Bear Branch, Catoctin State Forest, Thrumont, Maryland). These comparisons were based on atmospheric input to streGeology-based method of assessing sensitivity of streams to acidic deposition in Charles and Anne Arundel Counties, Maryland
The report describes the results of a study to assess the sensitivity of streams to acidic deposition in Charles and Anne Arundel Counties, Maryland using a geology-based method. Water samples were collected from streams in July and August 1988 when streams were at base-flow conditions. Eighteen water samples collected from streams in Charles County, and 17 water samples from streams in Anne ArundMystery solved: White deposit on streambeds proves to be diatoms
In the late winter and early spring of 2006 an unusual white deposit was observed on rocks and margins of streambeds in a number of park streams. Inquiries were made to park staff and scientists studying water resources in the park as to what the deposit was and did it pose any type of risk. A number of explanations were proposed, but it was not until samples were collected and examined with a scaAssessment of salinity intrusion in the James and Chickahominy Rivers as a result of simulated sea-level rise in Chesapeake Bay, East Coast, USA
Global sea level is rising, and the relative rate in the Chesapeake Bay region of the East Coast of the United States is greater than the worldwide rate. Sea-level rise can cause saline water to migrate upstream in estuaries and rivers, threatening freshwater habitat and drinking-water supplies. The effects of future sea-level rise on two tributaries of Chesapeake Bay, the James and Chickahominy (Comparison of mineral weathering and biomass nutrient uptake in two small forested watersheds underlain by quartzite bedrock, Catoctin Mountain, Maryland, USA
To quantify chemical weathering and biological uptake, mass-balance calculations were performed on two small forested watersheds located in the Blue Ridge Physiographic Province in north-central Maryland, USA. Both watersheds, Bear Branch (BB) and Fishing Creek Tributary (FCT), are underlain by relatively unreactive quartzite bedrock. Such unreactive bedrock and associated low chemical-weatheringReply to comment on “Anthropogenic sources of arsenic and copper to sediments in a suburban lake, northern Virginia"
Saxe and Beck (1) raise two groups of questions regarding the mass-balance approach in our paper.(i) Only some of the data and calculations used for the mass balance were provided; the apparent number of samples collected is not sufficient to support a reliable mass balance; measurements were not made on all tributaries. - News
- Data
Fort Belvoir, Virginia, stream-water, streambed-sediment, and soil data collected in 2019
Field parameters and chemical-analysis results of stream water, streambed sediment, and soil data collected during 2019 at Fort Belvoir, Virginia are presented. - Multimedia