Martha A Scholl
Martha Scholl is a research hydrologist in the Earth System Processes Division, Water Cycle Branch of the USGS Water Resources Mission Area. Her work includes synthesizing stable isotope tracer methods with precipitation and land cover characteristics to determine climate patterns that control groundwater recharge and streamflow.
Primary research topics are 1) Water availability in forested mountain watersheds: Mountain forests provide a steady, sustainable supply of high-quality water, and our research aims to improve understanding of the geologic, land cover and atmospheric interactions that affect this important resource; and 2) Ecohydrology of cloud and fog systems: Cloud water and fog inputs sustain important coastal and mountain ecosystems on six continents. Research is directed toward quantifying this unmeasured precipitation source in the water balance, including contributions to soil moisture, transpiration suppression, recharge and streamflow.
Professional Experience
2017 – present: Team Lead/ Team Member, Earth System Processes Division, USGS, Reston, VA
1995 – 2017: Research Hydrologist, National Research Program, USGS, Reston, VA
1989 – 1995: Research Hydrologist, National Research Program, USGS, Menlo Park, CA
Education and Certifications
M.S. 1989 University of Virginia, Environmental Sciences (Hydrology)
B.S. 1985 University of Minnesota Duluth, Geology
Science and Products
Stable hydrogen and oxygen isotopic compositions of precipitation samples from selected Virginia and West Virginia National Atmospheric Deposition Program (NADP) sites
The stable hydrogen (delta 2H) and oxygen (delta 18O) isotopic compositions of more than 1,400 daily or weekly composite samples of precipitation from four National Atmospheric Deposition Program (NADP) sites (VA10, VA27, VA28, and WV99) in Virginia and West Virginia were analyzed on archived samples obtained from NADP over various time periods from as early as 1998. The samples are from...
Stable hydrogen and oxygen isotopic compositions of precipitation samples from selected Colorado and Utah National Atmospheric Deposition Program (NADP) sites
The stable hydrogen (delta 2H) and oxygen (delta 18O) isotopic compositions of more than 4,300 weekly composite samples of precipitation from thirteen National Atmospheric Deposition Program (NADP) sites (CO02, CO08, CO09, CO10, CO21, CO89, CO91, CO92, CO93, CO96, CO97, CO98, and UT09) in Colorado and Utah were analyzed on archived samples obtained from NADP over various time periods...
Stable hydrogen and oxygen isotopic compositions of precipitation samples from selected Delaware, Maryland, New Jersey, New York, and Pennsylvania National Atmospheric Deposition Program (NADP) sites
The stable hydrogen (delta 2H) and oxygen (delta 18O) isotopic compositions of more than 6,400 daily or weekly composite samples of precipitation from nine National Atmospheric Deposition Program (NADP) sites (DE02, MD07, NJ99, NY67, NY68, PA00, PA15, PA72, and PA98) in New York, New Jersey, Delaware, Maryland and Pennsylvania were analyzed on archived samples obtained from NADP over...
Temperature, relative humidity and cloud immersion data for Luquillo Mountains, eastern Puerto Rico, 2014-2019
Supplementary data for studies conducted in the Luquillo Experimental Forest (LEF), eastern Puerto Rico include measurements of temperature, relative humidity and cloud immersion at 30-minute resolution. Temperature and relative humidity were measured at five sites; two primary sites have records from March 2014 to June 2019; other sites have shorter records within that period. From...
Geospatial data for Luquillo Mountains, Puerto Rico: Mean annual precipitation, elevation, watershed outlines, and rain gage locations
These geospatial data sets were developed as part of a new analysis of all known current and historical rain gages in the Luquillo Mountains, Puerto Rico published in the journal article Murphy, S.F., Stallard, R.F., Scholl, M.A., Gonzalez, G., and Torres-Sanchez, A.J., 2017, Reassessing rainfall in the Luquillo Mountains, Puerto Rico: Local and global ecohydrological implications: PLOS...
Supplementary Data for Method for Quantifying Cloud Immersion in a Tropical Mountain Forest Using Time-Lapse Photography
These data are mean temperature, relative humidity, dew point and cloud immersion with hour of day for sites in El Yunque National Forest, Puerto Rico. These data support the following publication: Bassiouni, M., Scholl, M.A., Torres-Sanchez, A.J., Murphy, S.F., in review, A Method for Quantifying Cloud Immersion in a Tropical Mountain Forest Using Time-Lapse Photography, Agricultural...
Filter Total Items: 32
The National integrated water availability assessment, water years 2010–20
Water availability is fundamentally important to human well-being, economic vitality, and ecosystem health. Because of its central importance, the U.S. Congress tasked the U.S. Geological Survey (USGS) and other Federal agencies with conducting regular, comprehensive assessments of water availability in the United States through the requirements under the SECURE Water Act. In response to...
Authors
Edward G. Stets, Althea A. Archer, James R. Degnan, Melinda Erickson, Galen Gorski, Laura Medalie, Martha A. Scholl
Water supply in the conterminous United States, Alaska, Hawaii, and Puerto Rico, water years 2010–20
We present an assessment of water supply across the conterminous United States (CONUS), Alaska, Hawaii, and Puerto Rico covering water years 2010–20. Our analysis drew on two national hydrologic models, the National Hydrologic Model Precipitation-Runoff Modeling System and the Weather Research and Forecasting model hydrologic modeling system. Both models produced estimates of streamflow...
Authors
Galen Gorski, Edward G. Stets, Martha A. Scholl, James R. Degnan, John R. Mullaney, Amy E. Galanter, Anthony J. Martinez, Julie Padilla, Jacob LaFontaine, Hayley R. Corson-Dosch, Allen Shapiro
Climate change and future water availability in the United States
The steady rise in global temperature as a result of human activity is causing changes in Earth’s water cycle. The balance of water stored within and moving between vapor, liquid, and frozen states in the water cycle is shifting, with consequences for water availability that include increases in drought, fire weather, flooding, and heavy precipitation, as well as cryosphere decline and...
Authors
Martha A. Scholl, Gregory J. McCabe, Carolyn G. Olson, Kathryn A. Powlen
Forest cover lessens hurricane impacts on peak streamflow
Cyclonic storms (i.e., hurricanes) are powerful disturbance events that often cause widespread forest damage. Storm-related canopy damage reduces rainfall interception and evapotranspiration, but impacts on streamflow regimes are poorly understood. We quantify streamflow changes in Puerto Rico following Hurricane Maria in September 2017, and evaluate whether forest cover and storm...
Authors
Jazlynn S. Hall, Martha A. Scholl, James B. Shanley, Serena Matt, María Uriarte
Extreme rainstorms drive exceptional organic carbon export from forested humid-tropical rivers in Puerto Rico
Extreme rainfall events in the humid-tropical Luquillo Mountains, Puerto Rico export the bulk of suspended sediment and particulate organic carbon. Using 25 years of river carbon and suspended sediment data, which targeted hurricanes and other large rainstorms, we estimated biogenic particulate organic carbon yields of 65 ± 16 tC km−2 yr−1 for the Icacos and 17.7 ± 5.1 tC km−2 yr−1 for...
Authors
Kasey E. Clark, Robert Stallard, Sheila F. Murphy, Martha A. Scholl, Grizelle González, Alain F. Plante, William H. McDowell
Forest cover lessens the impact of drought on streamflow in Puerto Rico
Tropical regions are experiencing high rates of forest cover loss coupled with changes in the volume and timing of rainfall. These shifts can compromise streamflow and water provision, highlighting the need to identify how forest cover influences streamflow generation under variable rainfall conditions. Although rainfall is the key driver of streamflow regimes, the role of forests is...
Authors
Jazlynn S. Hall, Martha A. Scholl, Yuri Gorokhovich, María Uriarte
Anomalous noble gas solubility in liquid cloud water: Possible implications for noble gas temperatures and cloud physics
The noble gas temperature climate proxy is an established tool that has previously been applied to determine the source of groundwater recharge, however, unanswered questions remain. In fractured media (e.g., volcanic islands) recharge can be so rapid that groundwater is significantly depleted in heavy noble gases, indicating that the water has retained noble gas concentrations from...
Authors
Chris M. Hall, M. Clara Castro, Martha A. Scholl, Julien Amalberti, Stephen Gingerich
Drought stress and hurricane defoliation influence mountain clouds and moisture recycling in a tropical forest
Mountain ranges generate clouds, precipitation, and perennial streamflow for water supplies, but the role of forest cover in mountain hydrometeorology and cloud formation is not well understood. In the Luquillo Experimental Forest of Puerto Rico, mountains are immersed in clouds nightly, providing a steady precipitation source to support the tropical forest ecosystems and human uses. A...
Authors
Martha A. Scholl, Maoya Bassiouni, Angel J. Torres-Sanchez
Groundwater dynamics at Kīlauea Volcano and vicinity, Hawaiʻi
Kīlauea Volcano, on the Island of Hawaiʻi, is surrounded and permeated by active groundwater systems that interact dynamically with the volcanic system. A generalized conceptual model of Hawaiian hydrogeology includes high-level dike-impounded groundwater, very permeable perched and basal aquifers, and a transition (mixing) zone between freshwater and saltwater. Most high-level...
Authors
Shaul Hurwitz, Sara E. Peek, Martha A. Scholl, Deborah Bergfeld, William C. Evans, James P. Kauahikaua, Stephen Gingerich, Paul A. Hsieh, R. Lopaka Lee, Edward F. Younger, Steven E. Ingebritsen
A 42 year inference of cloud base height trends in the Luquillo Mountains of northeastern Puerto Rico
The Luquillo Mountains of eastern Puerto Rico are home to the only tropical rainforest managed by the United States Forest Service, with cloud-immersed forests historically occupying the highest elevations. However, within the past 50 yr, studies of the Luquillo cloud forest have suggested an increase in cloud base heights (CBH), although the CBH in the area was not quantified until...
Authors
Paul W. Miller, Thomas L. Mote, C.A. Ramseyer, Ashley E. Van Beusekom, Martha A. Scholl, Grizelle González
Seasonality of stable isotope composition of atmospheric water input at the southern slopes of Mt. Kilimanjaro, Tanzania
To understand the moisture regime at the southern slopes of Mt. Kilimanjaro, we analysed the isotopic variability of oxygen (δ18O) and hydrogen (δD) of rainfall, throughfall, and fog from a total of 2,140 samples collected weekly over 2 years at 9 study sites along an elevation transect ranging from 950 to 3,880 m above sea level. Precipitation in the Kilimanjaro tropical rainforests...
Authors
Insa Otte, Florian Detsch, Adrian Gutlein, Martha A. Scholl, Ralf Kiese, Tim Appelhans, Thomas Nauss
A method for quantifying cloud immersion in a tropical mountain forest using time-lapse photography
Quantifying the frequency, duration, and elevation range of fog or cloud immersion is essential to estimate cloud water deposition in water budgets and to understand the ecohydrology of cloud forests. The goal of this study was to develop a low-cost and high spatial-coverage method to detect occurrence of cloud immersion within a mountain cloud forest by using time-lapse photography...
Authors
Maoya Bassiouni, Martha A. Scholl, Angel J. Torres-Sanchez, Sheila F. Murphy
Science and Products
Stable hydrogen and oxygen isotopic compositions of precipitation samples from selected Virginia and West Virginia National Atmospheric Deposition Program (NADP) sites
The stable hydrogen (delta 2H) and oxygen (delta 18O) isotopic compositions of more than 1,400 daily or weekly composite samples of precipitation from four National Atmospheric Deposition Program (NADP) sites (VA10, VA27, VA28, and WV99) in Virginia and West Virginia were analyzed on archived samples obtained from NADP over various time periods from as early as 1998. The samples are from...
Stable hydrogen and oxygen isotopic compositions of precipitation samples from selected Colorado and Utah National Atmospheric Deposition Program (NADP) sites
The stable hydrogen (delta 2H) and oxygen (delta 18O) isotopic compositions of more than 4,300 weekly composite samples of precipitation from thirteen National Atmospheric Deposition Program (NADP) sites (CO02, CO08, CO09, CO10, CO21, CO89, CO91, CO92, CO93, CO96, CO97, CO98, and UT09) in Colorado and Utah were analyzed on archived samples obtained from NADP over various time periods...
Stable hydrogen and oxygen isotopic compositions of precipitation samples from selected Delaware, Maryland, New Jersey, New York, and Pennsylvania National Atmospheric Deposition Program (NADP) sites
The stable hydrogen (delta 2H) and oxygen (delta 18O) isotopic compositions of more than 6,400 daily or weekly composite samples of precipitation from nine National Atmospheric Deposition Program (NADP) sites (DE02, MD07, NJ99, NY67, NY68, PA00, PA15, PA72, and PA98) in New York, New Jersey, Delaware, Maryland and Pennsylvania were analyzed on archived samples obtained from NADP over...
Temperature, relative humidity and cloud immersion data for Luquillo Mountains, eastern Puerto Rico, 2014-2019
Supplementary data for studies conducted in the Luquillo Experimental Forest (LEF), eastern Puerto Rico include measurements of temperature, relative humidity and cloud immersion at 30-minute resolution. Temperature and relative humidity were measured at five sites; two primary sites have records from March 2014 to June 2019; other sites have shorter records within that period. From...
Geospatial data for Luquillo Mountains, Puerto Rico: Mean annual precipitation, elevation, watershed outlines, and rain gage locations
These geospatial data sets were developed as part of a new analysis of all known current and historical rain gages in the Luquillo Mountains, Puerto Rico published in the journal article Murphy, S.F., Stallard, R.F., Scholl, M.A., Gonzalez, G., and Torres-Sanchez, A.J., 2017, Reassessing rainfall in the Luquillo Mountains, Puerto Rico: Local and global ecohydrological implications: PLOS...
Supplementary Data for Method for Quantifying Cloud Immersion in a Tropical Mountain Forest Using Time-Lapse Photography
These data are mean temperature, relative humidity, dew point and cloud immersion with hour of day for sites in El Yunque National Forest, Puerto Rico. These data support the following publication: Bassiouni, M., Scholl, M.A., Torres-Sanchez, A.J., Murphy, S.F., in review, A Method for Quantifying Cloud Immersion in a Tropical Mountain Forest Using Time-Lapse Photography, Agricultural...
Filter Total Items: 32
The National integrated water availability assessment, water years 2010–20
Water availability is fundamentally important to human well-being, economic vitality, and ecosystem health. Because of its central importance, the U.S. Congress tasked the U.S. Geological Survey (USGS) and other Federal agencies with conducting regular, comprehensive assessments of water availability in the United States through the requirements under the SECURE Water Act. In response to...
Authors
Edward G. Stets, Althea A. Archer, James R. Degnan, Melinda Erickson, Galen Gorski, Laura Medalie, Martha A. Scholl
Water supply in the conterminous United States, Alaska, Hawaii, and Puerto Rico, water years 2010–20
We present an assessment of water supply across the conterminous United States (CONUS), Alaska, Hawaii, and Puerto Rico covering water years 2010–20. Our analysis drew on two national hydrologic models, the National Hydrologic Model Precipitation-Runoff Modeling System and the Weather Research and Forecasting model hydrologic modeling system. Both models produced estimates of streamflow...
Authors
Galen Gorski, Edward G. Stets, Martha A. Scholl, James R. Degnan, John R. Mullaney, Amy E. Galanter, Anthony J. Martinez, Julie Padilla, Jacob LaFontaine, Hayley R. Corson-Dosch, Allen Shapiro
Climate change and future water availability in the United States
The steady rise in global temperature as a result of human activity is causing changes in Earth’s water cycle. The balance of water stored within and moving between vapor, liquid, and frozen states in the water cycle is shifting, with consequences for water availability that include increases in drought, fire weather, flooding, and heavy precipitation, as well as cryosphere decline and...
Authors
Martha A. Scholl, Gregory J. McCabe, Carolyn G. Olson, Kathryn A. Powlen
Forest cover lessens hurricane impacts on peak streamflow
Cyclonic storms (i.e., hurricanes) are powerful disturbance events that often cause widespread forest damage. Storm-related canopy damage reduces rainfall interception and evapotranspiration, but impacts on streamflow regimes are poorly understood. We quantify streamflow changes in Puerto Rico following Hurricane Maria in September 2017, and evaluate whether forest cover and storm...
Authors
Jazlynn S. Hall, Martha A. Scholl, James B. Shanley, Serena Matt, María Uriarte
Extreme rainstorms drive exceptional organic carbon export from forested humid-tropical rivers in Puerto Rico
Extreme rainfall events in the humid-tropical Luquillo Mountains, Puerto Rico export the bulk of suspended sediment and particulate organic carbon. Using 25 years of river carbon and suspended sediment data, which targeted hurricanes and other large rainstorms, we estimated biogenic particulate organic carbon yields of 65 ± 16 tC km−2 yr−1 for the Icacos and 17.7 ± 5.1 tC km−2 yr−1 for...
Authors
Kasey E. Clark, Robert Stallard, Sheila F. Murphy, Martha A. Scholl, Grizelle González, Alain F. Plante, William H. McDowell
Forest cover lessens the impact of drought on streamflow in Puerto Rico
Tropical regions are experiencing high rates of forest cover loss coupled with changes in the volume and timing of rainfall. These shifts can compromise streamflow and water provision, highlighting the need to identify how forest cover influences streamflow generation under variable rainfall conditions. Although rainfall is the key driver of streamflow regimes, the role of forests is...
Authors
Jazlynn S. Hall, Martha A. Scholl, Yuri Gorokhovich, María Uriarte
Anomalous noble gas solubility in liquid cloud water: Possible implications for noble gas temperatures and cloud physics
The noble gas temperature climate proxy is an established tool that has previously been applied to determine the source of groundwater recharge, however, unanswered questions remain. In fractured media (e.g., volcanic islands) recharge can be so rapid that groundwater is significantly depleted in heavy noble gases, indicating that the water has retained noble gas concentrations from...
Authors
Chris M. Hall, M. Clara Castro, Martha A. Scholl, Julien Amalberti, Stephen Gingerich
Drought stress and hurricane defoliation influence mountain clouds and moisture recycling in a tropical forest
Mountain ranges generate clouds, precipitation, and perennial streamflow for water supplies, but the role of forest cover in mountain hydrometeorology and cloud formation is not well understood. In the Luquillo Experimental Forest of Puerto Rico, mountains are immersed in clouds nightly, providing a steady precipitation source to support the tropical forest ecosystems and human uses. A...
Authors
Martha A. Scholl, Maoya Bassiouni, Angel J. Torres-Sanchez
Groundwater dynamics at Kīlauea Volcano and vicinity, Hawaiʻi
Kīlauea Volcano, on the Island of Hawaiʻi, is surrounded and permeated by active groundwater systems that interact dynamically with the volcanic system. A generalized conceptual model of Hawaiian hydrogeology includes high-level dike-impounded groundwater, very permeable perched and basal aquifers, and a transition (mixing) zone between freshwater and saltwater. Most high-level...
Authors
Shaul Hurwitz, Sara E. Peek, Martha A. Scholl, Deborah Bergfeld, William C. Evans, James P. Kauahikaua, Stephen Gingerich, Paul A. Hsieh, R. Lopaka Lee, Edward F. Younger, Steven E. Ingebritsen
A 42 year inference of cloud base height trends in the Luquillo Mountains of northeastern Puerto Rico
The Luquillo Mountains of eastern Puerto Rico are home to the only tropical rainforest managed by the United States Forest Service, with cloud-immersed forests historically occupying the highest elevations. However, within the past 50 yr, studies of the Luquillo cloud forest have suggested an increase in cloud base heights (CBH), although the CBH in the area was not quantified until...
Authors
Paul W. Miller, Thomas L. Mote, C.A. Ramseyer, Ashley E. Van Beusekom, Martha A. Scholl, Grizelle González
Seasonality of stable isotope composition of atmospheric water input at the southern slopes of Mt. Kilimanjaro, Tanzania
To understand the moisture regime at the southern slopes of Mt. Kilimanjaro, we analysed the isotopic variability of oxygen (δ18O) and hydrogen (δD) of rainfall, throughfall, and fog from a total of 2,140 samples collected weekly over 2 years at 9 study sites along an elevation transect ranging from 950 to 3,880 m above sea level. Precipitation in the Kilimanjaro tropical rainforests...
Authors
Insa Otte, Florian Detsch, Adrian Gutlein, Martha A. Scholl, Ralf Kiese, Tim Appelhans, Thomas Nauss
A method for quantifying cloud immersion in a tropical mountain forest using time-lapse photography
Quantifying the frequency, duration, and elevation range of fog or cloud immersion is essential to estimate cloud water deposition in water budgets and to understand the ecohydrology of cloud forests. The goal of this study was to develop a low-cost and high spatial-coverage method to detect occurrence of cloud immersion within a mountain cloud forest by using time-lapse photography...
Authors
Maoya Bassiouni, Martha A. Scholl, Angel J. Torres-Sanchez, Sheila F. Murphy