Sheila Murphy
Sheila Murphy is a Research Hydrologist for the USGS Water Resources Mission Area.
Sheila Murphy is a research hydrologist who focuses on how disturbances (such as wildfire, floods, hurricanes, land use change) alter watershed response, water quality, and water quantity. Her recent research has evaluated the effects of wildfire on water quality in the western U.S., and the hydrologic and geochemical responses to land cover change and hurricanes in a tropical forest in Puerto Rico.
Science and Products
Filter Total Items: 52
Reassessing rainfall in the Luquillo Mountains, Puerto Rico: Local and global ecohydrological implications
Mountains receive a greater proportion of precipitation than other environments, and thus make a disproportionate contribution to the world’s water supply. The Luquillo Mountains receive the highest rainfall on the island of Puerto Rico and serve as a critical source of water to surrounding communities. The area’s role as a long-term research site has generated numerous hydrological, ecological, a
Authors
Sheila F. Murphy, Robert F. Stallard, Martha A. Scholl, Grizelle Gonzalez, Angel J. Torres-Sanchez
Critical zone properties control the fate of nitrogen during experimental rainfall in montane forests of the Colorado Front Range
Several decades of research in alpine ecosystems have demonstrated links among the critical zone, hydrologic response, and the fate of elevated atmospheric nitrogen (N) deposition. Less research has occurred in mid-elevation forests, which may be important for retaining atmospheric N deposition. To explore the fate of N in the montane zone, we conducted plot-scale experimental rainfall events acro
Authors
Eve-Lyn S. Hinckley, Brian A. Ebel, Rebecca T. Barnes, Sheila F. Murphy, Suzanne P. Anderson
Water-quality response to a high-elevation wildfire in the Colorado Front Range
Water quality of the Big Thompson River in the Front Range of Colorado was studied for 2 years following a high‐elevation wildfire that started in October 2012 and burned 15% of the watershed. A combination of fixed‐interval sampling and continuous water‐quality monitors was used to examine the timing and magnitude of water‐quality changes caused by the wildfire. Prefire water quality was well cha
Authors
M. Alisa Mast, Sheila F. Murphy, David W. Clow, Colin A. Penn, Graham A. Sexstone
The role of precipitation type, intensity, and spatial distribution in source water quality after wildfire
Storms following wildfires are known to impair drinking water supplies in the southwestern United States, yet our understanding of the role of precipitation in post-wildfire water quality is far from complete. We quantitatively assessed water-quality impacts of different hydrologic events in the Colorado Front Range and found that for a three-year period, substantial hydrologic and geochemical res
Authors
Sheila F. Murphy, Jeffrey H. Writer, R. Blaine McCleskey, Deborah A. Martin
Stable-isotope and solute-chemistry approaches to flow characterization in a forested tropical watershed, Luquillo Mountains, Puerto Rico
The prospect of changing climate has led to uncertainty about the resilience of forested mountain watersheds in the tropics. In watersheds where frequent, high rainfall provides ample runoff, we often lack understanding of how the system will respond under conditions of decreased rainfall or drought. Factors that govern water supply, such as recharge rates and groundwater storage capacity, may be
Authors
Martha A. Scholl, James B. Shanley, Sheila F. Murphy, Jane K Willenbring, Marcie Occhi, Grizelle González
Precipitation isotopes link regional climate patterns to water supply in a tropical mountain forest, eastern Puerto Rico
Like many mountainous areas in the tropics, watersheds in the Luquillo Mountains of eastern Puerto Rico have abundant rainfall and stream discharge and provide much of the water supply for the densely populated metropolitan areas nearby. Projected changes in regional temperature and atmospheric dynamics as a result of global warming suggest that water availability will be affected by changes in ra
Authors
Martha A. Scholl, Sheila F. Murphy
A unified assessment of hydrological and biogeochemical responses in research watersheds in Eastern Puerto Rico using runoff-concentration relations
An examination of the relation between runoff rate, R, and concentration, C, of twelve major constituents in four small watersheds in eastern Puerto Rico demonstrates a consistent pattern of responses. For solutes that are not substantially bioactive (alkalinity, silica, calcium, magnesium, sodium, and chloride), the log(R)–log(C) relation is almost linear and can be described as a weighted averag
Authors
Robert F. Stallard, Sheila F. Murphy
Evaluation of wastewater contaminant transport in surface waters using verified Lagrangian sampling
Contaminants released from wastewater treatment plants can persist in surface waters for substantial distances. Much research has gone into evaluating the fate and transport of these contaminants, but this work has often assumed constant flow from wastewater treatment plants. However, effluent discharge commonly varies widely over a 24-hour period, and this variation controls contaminant loading a
Authors
Ronald C. Antweiler, Jeffrey H. Writer, Sheila F. Murphy
Weathering processes in the Rio Icacos and Rio Mameyes watersheds in Eastern Puerto Rico: Chapter I in Water quality and landscape processes of four watersheds in eastern Puerto Rico
Streams draining watersheds of the two dominant lithologies (quartz diorite and volcaniclastic rock) in the Luquillo Experimental Forest of eastern Puerto Rico have very high fluxes of bedrock weathering products. The Río Blanco quartz diorite in the Icacos watershed and the Fajardo volcaniclastic rocks in the Mameyes watershed have some of the fastest documented rates of chemical weathering of si
Authors
Heather L. Buss, Arthur F. White
Physiography, geology, and land cover of four watersheds in eastern Puerto Rico: Chapter A in Water quality and landscape processes of four watersheds in eastern Puerto Rico
Four watersheds with differing geology and land cover in eastern Puerto Rico have been studied on a long-term basis by the U.S. Geological Survey to evaluate water, energy, and biogeochemical budgets. These watersheds are typical of tropical, island-arc settings found in many parts of the world. Two watersheds are located on coarse-grained granitic rocks that weather to quartz- and clay-rich, sand
Authors
Sheila F. Murphy, Robert F. Stallard, Matthew C. Larsen, William A. Gould
Weathering, landscape equilibrium, and carbon in four watersheds in eastern Puerto Rico: Chapter H in Water quality and landscape processes of four watersheds in eastern Puerto Rico
The U.S. Geological Survey's Water, Energy, and Biogeochemical Budgets (WEBB) program research in eastern Puerto Rico involves a double pair-wise comparison of four montane river basins, two on granitic bedrock and two on fine-grained volcaniclastic bedrock; for each rock type, one is forested and the other is developed. A confounding factor in this comparison is that the developed watersheds are
Authors
Robert F. Stallard
Land use, population dynamics, and land-cover change in eastern Puerto Rico: Chapter B in Water quality and landscape processes of four watersheds in eastern Puerto Rico
We assessed current and historic land use and land cover in the Luquillo Mountains and surrounding area in eastern Puerto Rico, including four small subwatersheds that are study watersheds of the U.S. Geological Survey's Water, Energy, and Biogeochemical Budgets (WEBB) program. This region occupies an area of 1,616 square kilometers, about 18 percent of the total land in Puerto Rico. Closed forest
Authors
William A. Gould, Sebastián Martinuzzi, Isabel K. Pares-Ramos, Sheila F. Murphy, Robert F. Stallard
Science and Products
Filter Total Items: 52
Reassessing rainfall in the Luquillo Mountains, Puerto Rico: Local and global ecohydrological implications
Mountains receive a greater proportion of precipitation than other environments, and thus make a disproportionate contribution to the world’s water supply. The Luquillo Mountains receive the highest rainfall on the island of Puerto Rico and serve as a critical source of water to surrounding communities. The area’s role as a long-term research site has generated numerous hydrological, ecological, a
Authors
Sheila F. Murphy, Robert F. Stallard, Martha A. Scholl, Grizelle Gonzalez, Angel J. Torres-Sanchez
Critical zone properties control the fate of nitrogen during experimental rainfall in montane forests of the Colorado Front Range
Several decades of research in alpine ecosystems have demonstrated links among the critical zone, hydrologic response, and the fate of elevated atmospheric nitrogen (N) deposition. Less research has occurred in mid-elevation forests, which may be important for retaining atmospheric N deposition. To explore the fate of N in the montane zone, we conducted plot-scale experimental rainfall events acro
Authors
Eve-Lyn S. Hinckley, Brian A. Ebel, Rebecca T. Barnes, Sheila F. Murphy, Suzanne P. Anderson
Water-quality response to a high-elevation wildfire in the Colorado Front Range
Water quality of the Big Thompson River in the Front Range of Colorado was studied for 2 years following a high‐elevation wildfire that started in October 2012 and burned 15% of the watershed. A combination of fixed‐interval sampling and continuous water‐quality monitors was used to examine the timing and magnitude of water‐quality changes caused by the wildfire. Prefire water quality was well cha
Authors
M. Alisa Mast, Sheila F. Murphy, David W. Clow, Colin A. Penn, Graham A. Sexstone
The role of precipitation type, intensity, and spatial distribution in source water quality after wildfire
Storms following wildfires are known to impair drinking water supplies in the southwestern United States, yet our understanding of the role of precipitation in post-wildfire water quality is far from complete. We quantitatively assessed water-quality impacts of different hydrologic events in the Colorado Front Range and found that for a three-year period, substantial hydrologic and geochemical res
Authors
Sheila F. Murphy, Jeffrey H. Writer, R. Blaine McCleskey, Deborah A. Martin
Stable-isotope and solute-chemistry approaches to flow characterization in a forested tropical watershed, Luquillo Mountains, Puerto Rico
The prospect of changing climate has led to uncertainty about the resilience of forested mountain watersheds in the tropics. In watersheds where frequent, high rainfall provides ample runoff, we often lack understanding of how the system will respond under conditions of decreased rainfall or drought. Factors that govern water supply, such as recharge rates and groundwater storage capacity, may be
Authors
Martha A. Scholl, James B. Shanley, Sheila F. Murphy, Jane K Willenbring, Marcie Occhi, Grizelle González
Precipitation isotopes link regional climate patterns to water supply in a tropical mountain forest, eastern Puerto Rico
Like many mountainous areas in the tropics, watersheds in the Luquillo Mountains of eastern Puerto Rico have abundant rainfall and stream discharge and provide much of the water supply for the densely populated metropolitan areas nearby. Projected changes in regional temperature and atmospheric dynamics as a result of global warming suggest that water availability will be affected by changes in ra
Authors
Martha A. Scholl, Sheila F. Murphy
A unified assessment of hydrological and biogeochemical responses in research watersheds in Eastern Puerto Rico using runoff-concentration relations
An examination of the relation between runoff rate, R, and concentration, C, of twelve major constituents in four small watersheds in eastern Puerto Rico demonstrates a consistent pattern of responses. For solutes that are not substantially bioactive (alkalinity, silica, calcium, magnesium, sodium, and chloride), the log(R)–log(C) relation is almost linear and can be described as a weighted averag
Authors
Robert F. Stallard, Sheila F. Murphy
Evaluation of wastewater contaminant transport in surface waters using verified Lagrangian sampling
Contaminants released from wastewater treatment plants can persist in surface waters for substantial distances. Much research has gone into evaluating the fate and transport of these contaminants, but this work has often assumed constant flow from wastewater treatment plants. However, effluent discharge commonly varies widely over a 24-hour period, and this variation controls contaminant loading a
Authors
Ronald C. Antweiler, Jeffrey H. Writer, Sheila F. Murphy
Weathering processes in the Rio Icacos and Rio Mameyes watersheds in Eastern Puerto Rico: Chapter I in Water quality and landscape processes of four watersheds in eastern Puerto Rico
Streams draining watersheds of the two dominant lithologies (quartz diorite and volcaniclastic rock) in the Luquillo Experimental Forest of eastern Puerto Rico have very high fluxes of bedrock weathering products. The Río Blanco quartz diorite in the Icacos watershed and the Fajardo volcaniclastic rocks in the Mameyes watershed have some of the fastest documented rates of chemical weathering of si
Authors
Heather L. Buss, Arthur F. White
Physiography, geology, and land cover of four watersheds in eastern Puerto Rico: Chapter A in Water quality and landscape processes of four watersheds in eastern Puerto Rico
Four watersheds with differing geology and land cover in eastern Puerto Rico have been studied on a long-term basis by the U.S. Geological Survey to evaluate water, energy, and biogeochemical budgets. These watersheds are typical of tropical, island-arc settings found in many parts of the world. Two watersheds are located on coarse-grained granitic rocks that weather to quartz- and clay-rich, sand
Authors
Sheila F. Murphy, Robert F. Stallard, Matthew C. Larsen, William A. Gould
Weathering, landscape equilibrium, and carbon in four watersheds in eastern Puerto Rico: Chapter H in Water quality and landscape processes of four watersheds in eastern Puerto Rico
The U.S. Geological Survey's Water, Energy, and Biogeochemical Budgets (WEBB) program research in eastern Puerto Rico involves a double pair-wise comparison of four montane river basins, two on granitic bedrock and two on fine-grained volcaniclastic bedrock; for each rock type, one is forested and the other is developed. A confounding factor in this comparison is that the developed watersheds are
Authors
Robert F. Stallard
Land use, population dynamics, and land-cover change in eastern Puerto Rico: Chapter B in Water quality and landscape processes of four watersheds in eastern Puerto Rico
We assessed current and historic land use and land cover in the Luquillo Mountains and surrounding area in eastern Puerto Rico, including four small subwatersheds that are study watersheds of the U.S. Geological Survey's Water, Energy, and Biogeochemical Budgets (WEBB) program. This region occupies an area of 1,616 square kilometers, about 18 percent of the total land in Puerto Rico. Closed forest
Authors
William A. Gould, Sebastián Martinuzzi, Isabel K. Pares-Ramos, Sheila F. Murphy, Robert F. Stallard