Denis R LeBlanc
Denis LeBlanc is a Scientist Emeritus with the New England Water Science Center.
Denis conducts research on the hydrology of shallow, unconfined groundwater/surface-water systems and the fate and transport of contaminants.
He joined the USGS in 1975 and, until 1983, participated in and led investigations of Cape Cod's hydrologic system.
From 1983 until his retirement in 2023, he conducted and coordinated multidisciplinary research at the USGS Cape Cod Toxic Substances Hydrology Research site at the Joint Base Cape Cod (JBCC) near Falmouth, Mass. He also led the team that provided technical support to Air Force and Army National Guard environmental restoration programs at JBCC and participated in several projects with the U.S Environmental Protection Agency on nitrogen and other wastewater contaminants in Cape Cod's groundwater.
Denis received his B.S. in Hydrology from the University of New Hampshire and his M.S. in Civil and Environmental Engineering from the Massachusetts Institute of Technology.
He is a member of the National Ground Water Association and the Geological Society of America.
Professional Experience
Scientist Emeritus, U.S. Geological Survey, New England Water Science Center, 2023 to Present
Research Hydrologist, U.S. Geological Survey, New England Water Science Center, Cape Cod Toxic Substances Hydrology projects, 1983 to 2023
Hydrologist, U.S. Geological Survey, New England Water Science Center, Cape Cod Hydrology projects, 1975 to 1983
Oceanographic Field Assistant, Normandeau Associates, 1973 to 1975
Education and Certifications
M.S. Civil and Environmental Engineering, Massachusetts Institute of Technology, 2001
B.S. Hydrology, University of New Hampshire, 1975
Affiliations and Memberships*
Geological Society of America 1997, to Present
National Groundwater Association, 1977 to Present
Honors and Awards
Eugene M. Shoemaker Award for Lifetime Achievement in Communications, U.S. Geological Survey, 2020
Distinguished Service Award, Dept. of the Interior, 2016
Fellow, Geological Society of America, 2013
Meritorious Service Award, Dept. of the Interior, 1995
Science and Products
Filter Total Items: 23
No Result Found
40 Years Presenting Cape Cod Hydrology
USGS has studied the hydrology of Cape Cod and the Islands and demonstrated our science to the public for more than four decades. Many visitor groups from government agencies, universities, nonprofit organizations, and local communities have learned about our groundwater and surface water research in southeastern Massachusetts. USGS Research Hydrologist Emeritus Denis Leblanc has been a pillar in...
Filter Total Items: 67
Importance of the colmation layer in the transport and removal of cyanobacteria, viruses, and dissolved organic carbon during natural lake-bank filtration Importance of the colmation layer in the transport and removal of cyanobacteria, viruses, and dissolved organic carbon during natural lake-bank filtration
This study focused on the importance of the colmation layer in the removal of cyanobacteria, viruses, and dissolved organic carbon (DOC) during natural bank filtration. Injection-and-recovery studies were performed at two shallow (0.5 m deep), sandy, near-shore sites at the southern end of Ashumet Pond, a waste-impacted, kettle pond on Cape Cod, MA, that is subject to periodic blooms of
Authors
Ronald W. Harvey, David W. Metge, Denis R. LeBlanc, Jennifer C. Underwood, George R. Aiken, Kenna D. Butler, Timothy D. McCobb, Jay Jasperse
Science for the stewardship of the groundwater resources of Cape Cod, Massachusetts Science for the stewardship of the groundwater resources of Cape Cod, Massachusetts
Groundwater is the sole source of drinking water and a major source of freshwater for domestic, industrial, and agricultural uses on Cape Cod, Massachusetts. Groundwater discharged from aquifers also supports freshwater pond and stream ecosystems and coastal wetlands. Six hydraulically distinct groundwater-flow systems (lenses) have been delineated on Cape Cod. Of the approximately 450...
Authors
Jeffrey R. Barbaro, John P. Masterson, Denis R. LeBlanc
Mercury speciation and mobilization in a wastewater-contaminated groundwater plume Mercury speciation and mobilization in a wastewater-contaminated groundwater plume
We measured the concentration and speciation of mercury (Hg) in groundwater down-gradient from the site of wastewater infiltration beds operated by the Massachusetts Military Reservation, western Cape Cod, Massachusetts. Total mercury concentrations in oxic, mildly acidic, uncontaminated groundwater are 0.5–1 pM, and aquifer sediments have 0.5–1 ppb mercury. The plume of impacted...
Authors
Carl H. Lamborg, Doug B. Kent, Gretchen J. Swarr, Kathleen M. Munson, Tristan Kading, Alison E. O’Connor, Gillian M. Fairchild, Denis R. LeBlanc, Heather A. Wiatrowski
Transport of nitrogen in a treated-wastewater plume to coastal discharge areas, Ashumet Valley, Cape Cod, Massachusetts Transport of nitrogen in a treated-wastewater plume to coastal discharge areas, Ashumet Valley, Cape Cod, Massachusetts
Land disposal of treated wastewater from a treatment plant on the Massachusetts Military Reservation in operation from 1936 to 1995 has created a plume of contaminated groundwater that is migrating toward coastal discharge areas in the town of Falmouth, Massachusetts. To develop a better understanding of the potential impact of the treated-wastewater plume on coastal discharge areas, the...
Authors
Jeffrey R. Barbaro, Donald A. Walter, Denis R. LeBlanc
Long-term groundwater contamination after source removal—The role of sorbed carbon and nitrogen on the rate of reoxygenation of a treated-wastewater plume on Cape Cod, MA, USA Long-term groundwater contamination after source removal—The role of sorbed carbon and nitrogen on the rate of reoxygenation of a treated-wastewater plume on Cape Cod, MA, USA
The consequences of groundwater contamination can remain long after a contaminant source has been removed. Documentation of natural aquifer recoveries and empirical tools to predict recovery time frames and associated geochemical changes are generally lacking. This study characterized the long-term natural attenuation of a groundwater contaminant plume in a sand and gravel aquifer on...
Authors
Richard L. Smith, Deborah A. Repert, Larry B. Barber, Denis R. LeBlanc
Comparison of no-purge and pumped sampling methods for monitoring concentrations of ordnance-related compounds in groundwater, Camp Edwards, Massachusetts Military Reservation, Cape Cod, Massachusetts, 2009-2010 Comparison of no-purge and pumped sampling methods for monitoring concentrations of ordnance-related compounds in groundwater, Camp Edwards, Massachusetts Military Reservation, Cape Cod, Massachusetts, 2009-2010
Field tests were conducted near the Impact Area at Camp Edwards on the Massachusetts Military Reservation, Cape Cod, Massachusetts, to determine the utility of no-purge groundwater sampling for monitoring concentrations of ordnance-related explosive compounds and perchlorate in the sand and gravel aquifer. The no-purge methods included (1) a diffusion sampler constructed of rigid porous
Authors
Jennifer G. Savoie, Denis R. LeBlanc
Groundwater-quality data for a treated-wastewater plume near the Massachusetts Military Reservation, Ashumet Valley, Cape Cod, Massachusetts, 2006-08 Groundwater-quality data for a treated-wastewater plume near the Massachusetts Military Reservation, Ashumet Valley, Cape Cod, Massachusetts, 2006-08
A plume of contaminated groundwater extends from former disposal beds at the Massachusetts Military Reservation's wastewater-treatment plant toward Ashumet Pond, coastal ponds, and Vineyard Sound, Cape Cod, Massachusetts. Treated sewage-derived wastewater was discharged to the rapid-infiltration beds for nearly 60 years before the disposal site was moved to a different location in...
Authors
Jennifer G. Savoie, Denis R. LeBlanc, Gillian M. Fairchild, Richard L. Smith, Douglas B. Kent, Larry B. Barber, Deborah A. Repert, Charles P. Hart, Steffanie H. Keefe, Luke A. Parsons
Water-quality data from shallow pond-bottom groundwater in the Fishermans Cove area of Ashumet Pond, Cape Cod, Massachusetts, 2001-2010 Water-quality data from shallow pond-bottom groundwater in the Fishermans Cove area of Ashumet Pond, Cape Cod, Massachusetts, 2001-2010
The U.S. Geological Survey (USGS) collected water-quality data between 2001 and 2010 in the Fishermans Cove area of Ashumet Pond, Falmouth, Massachusetts, where the eastern portion of a treated-wastewater plume, created by more than 60 years of overland disposal, discharges to the pond. Temporary drive points were installed, and shallow pond-bottom groundwater was sampled, at 167...
Authors
Timothy D. McCobb, Denis R. LeBlanc
The influence of topology on hydraulic conductivity in a sand-and-gravel aquifer The influence of topology on hydraulic conductivity in a sand-and-gravel aquifer
A field experiment consisting of geophysical logging and tracer testing was conducted in a single well that penetrated a sand‐and‐gravel aquifer at the U.S. Geological Survey Toxic Substances Hydrology research site on Cape Cod, Massachusetts. Geophysical logs and flowmeter/pumping measurements were obtained to estimate vertical profiles of porosity ϕ, hydraulic conductivity K...
Authors
Roger H. Morin, Denis R. LeBlanc, Brent M. Troutman
Fate of sulfamethoxazole, 4-nonylphenol, and 17β-estradiol in groundwater contaminated by wastewater treatment plant effluent Fate of sulfamethoxazole, 4-nonylphenol, and 17β-estradiol in groundwater contaminated by wastewater treatment plant effluent
Organic wastewater contaminants (OWCs) were measured in samples collected from monitoring wells located along a 4.5-km transect of a plume of groundwater contaminated by 60 years of continuous rapid infiltration disposal of wastewater treatment plant effluent. Fifteen percent of the 212 OWCs analyzed were detected, including the antibiotic sulfamethoxazole (SX), the nonionic surfactant...
Authors
Larry B. Barber, Steffanie H. Keefe, Denis R. LeBlanc, Paul M. Bradley, Francis H. Chapelle, Michael T. Meyer, Keith A. Loftin, Dana W. Koplin, Fernando Rubio
Comparison of pumped and diffusion sampling methods to monitor concentrations of perchlorate and explosive compounds in ground water, Camp Edwards, Cape Cod, Massachusetts, 2004-05 Comparison of pumped and diffusion sampling methods to monitor concentrations of perchlorate and explosive compounds in ground water, Camp Edwards, Cape Cod, Massachusetts, 2004-05
Laboratory and field tests were conducted at Camp Edwards on the Massachusetts Military Reservation on Cape Cod to examine the utility of passive diffusion sampling for long-term monitoring of concentrations of perchlorate and explosive compounds in ground water. The diffusion samplers were constructed of 1-inch-diameter rigid, porous polyethylene tubing. The results of laboratory tests...
Authors
Denis R. LeBlanc, Don A. Vroblesky
Distribution and migration of ordnance-related compounds and oxygen and hydrogen stable isotopes in ground water near Snake Pond, Sandwich, Massachusetts Distribution and migration of ordnance-related compounds and oxygen and hydrogen stable isotopes in ground water near Snake Pond, Sandwich, Massachusetts
Explosive compounds, such as RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) and HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine), and the propellant compound perchlorate are present in ground water near Snake Pond, a ground-water flow-through glacial kettle pond in the glacial sand and gravel aquifer on western Cape Cod near Camp Edwards on the Massachusetts Military Reservation...
Authors
Denis R. LeBlanc, Andrew J. Massey, Jessica J. Cochrane, Jonathan H. King, Kirk P. Smith
Science and Products
Filter Total Items: 23
No Result Found
40 Years Presenting Cape Cod Hydrology
USGS has studied the hydrology of Cape Cod and the Islands and demonstrated our science to the public for more than four decades. Many visitor groups from government agencies, universities, nonprofit organizations, and local communities have learned about our groundwater and surface water research in southeastern Massachusetts. USGS Research Hydrologist Emeritus Denis Leblanc has been a pillar in...
Filter Total Items: 67
Importance of the colmation layer in the transport and removal of cyanobacteria, viruses, and dissolved organic carbon during natural lake-bank filtration Importance of the colmation layer in the transport and removal of cyanobacteria, viruses, and dissolved organic carbon during natural lake-bank filtration
This study focused on the importance of the colmation layer in the removal of cyanobacteria, viruses, and dissolved organic carbon (DOC) during natural bank filtration. Injection-and-recovery studies were performed at two shallow (0.5 m deep), sandy, near-shore sites at the southern end of Ashumet Pond, a waste-impacted, kettle pond on Cape Cod, MA, that is subject to periodic blooms of
Authors
Ronald W. Harvey, David W. Metge, Denis R. LeBlanc, Jennifer C. Underwood, George R. Aiken, Kenna D. Butler, Timothy D. McCobb, Jay Jasperse
Science for the stewardship of the groundwater resources of Cape Cod, Massachusetts Science for the stewardship of the groundwater resources of Cape Cod, Massachusetts
Groundwater is the sole source of drinking water and a major source of freshwater for domestic, industrial, and agricultural uses on Cape Cod, Massachusetts. Groundwater discharged from aquifers also supports freshwater pond and stream ecosystems and coastal wetlands. Six hydraulically distinct groundwater-flow systems (lenses) have been delineated on Cape Cod. Of the approximately 450...
Authors
Jeffrey R. Barbaro, John P. Masterson, Denis R. LeBlanc
Mercury speciation and mobilization in a wastewater-contaminated groundwater plume Mercury speciation and mobilization in a wastewater-contaminated groundwater plume
We measured the concentration and speciation of mercury (Hg) in groundwater down-gradient from the site of wastewater infiltration beds operated by the Massachusetts Military Reservation, western Cape Cod, Massachusetts. Total mercury concentrations in oxic, mildly acidic, uncontaminated groundwater are 0.5–1 pM, and aquifer sediments have 0.5–1 ppb mercury. The plume of impacted...
Authors
Carl H. Lamborg, Doug B. Kent, Gretchen J. Swarr, Kathleen M. Munson, Tristan Kading, Alison E. O’Connor, Gillian M. Fairchild, Denis R. LeBlanc, Heather A. Wiatrowski
Transport of nitrogen in a treated-wastewater plume to coastal discharge areas, Ashumet Valley, Cape Cod, Massachusetts Transport of nitrogen in a treated-wastewater plume to coastal discharge areas, Ashumet Valley, Cape Cod, Massachusetts
Land disposal of treated wastewater from a treatment plant on the Massachusetts Military Reservation in operation from 1936 to 1995 has created a plume of contaminated groundwater that is migrating toward coastal discharge areas in the town of Falmouth, Massachusetts. To develop a better understanding of the potential impact of the treated-wastewater plume on coastal discharge areas, the...
Authors
Jeffrey R. Barbaro, Donald A. Walter, Denis R. LeBlanc
Long-term groundwater contamination after source removal—The role of sorbed carbon and nitrogen on the rate of reoxygenation of a treated-wastewater plume on Cape Cod, MA, USA Long-term groundwater contamination after source removal—The role of sorbed carbon and nitrogen on the rate of reoxygenation of a treated-wastewater plume on Cape Cod, MA, USA
The consequences of groundwater contamination can remain long after a contaminant source has been removed. Documentation of natural aquifer recoveries and empirical tools to predict recovery time frames and associated geochemical changes are generally lacking. This study characterized the long-term natural attenuation of a groundwater contaminant plume in a sand and gravel aquifer on...
Authors
Richard L. Smith, Deborah A. Repert, Larry B. Barber, Denis R. LeBlanc
Comparison of no-purge and pumped sampling methods for monitoring concentrations of ordnance-related compounds in groundwater, Camp Edwards, Massachusetts Military Reservation, Cape Cod, Massachusetts, 2009-2010 Comparison of no-purge and pumped sampling methods for monitoring concentrations of ordnance-related compounds in groundwater, Camp Edwards, Massachusetts Military Reservation, Cape Cod, Massachusetts, 2009-2010
Field tests were conducted near the Impact Area at Camp Edwards on the Massachusetts Military Reservation, Cape Cod, Massachusetts, to determine the utility of no-purge groundwater sampling for monitoring concentrations of ordnance-related explosive compounds and perchlorate in the sand and gravel aquifer. The no-purge methods included (1) a diffusion sampler constructed of rigid porous
Authors
Jennifer G. Savoie, Denis R. LeBlanc
Groundwater-quality data for a treated-wastewater plume near the Massachusetts Military Reservation, Ashumet Valley, Cape Cod, Massachusetts, 2006-08 Groundwater-quality data for a treated-wastewater plume near the Massachusetts Military Reservation, Ashumet Valley, Cape Cod, Massachusetts, 2006-08
A plume of contaminated groundwater extends from former disposal beds at the Massachusetts Military Reservation's wastewater-treatment plant toward Ashumet Pond, coastal ponds, and Vineyard Sound, Cape Cod, Massachusetts. Treated sewage-derived wastewater was discharged to the rapid-infiltration beds for nearly 60 years before the disposal site was moved to a different location in...
Authors
Jennifer G. Savoie, Denis R. LeBlanc, Gillian M. Fairchild, Richard L. Smith, Douglas B. Kent, Larry B. Barber, Deborah A. Repert, Charles P. Hart, Steffanie H. Keefe, Luke A. Parsons
Water-quality data from shallow pond-bottom groundwater in the Fishermans Cove area of Ashumet Pond, Cape Cod, Massachusetts, 2001-2010 Water-quality data from shallow pond-bottom groundwater in the Fishermans Cove area of Ashumet Pond, Cape Cod, Massachusetts, 2001-2010
The U.S. Geological Survey (USGS) collected water-quality data between 2001 and 2010 in the Fishermans Cove area of Ashumet Pond, Falmouth, Massachusetts, where the eastern portion of a treated-wastewater plume, created by more than 60 years of overland disposal, discharges to the pond. Temporary drive points were installed, and shallow pond-bottom groundwater was sampled, at 167...
Authors
Timothy D. McCobb, Denis R. LeBlanc
The influence of topology on hydraulic conductivity in a sand-and-gravel aquifer The influence of topology on hydraulic conductivity in a sand-and-gravel aquifer
A field experiment consisting of geophysical logging and tracer testing was conducted in a single well that penetrated a sand‐and‐gravel aquifer at the U.S. Geological Survey Toxic Substances Hydrology research site on Cape Cod, Massachusetts. Geophysical logs and flowmeter/pumping measurements were obtained to estimate vertical profiles of porosity ϕ, hydraulic conductivity K...
Authors
Roger H. Morin, Denis R. LeBlanc, Brent M. Troutman
Fate of sulfamethoxazole, 4-nonylphenol, and 17β-estradiol in groundwater contaminated by wastewater treatment plant effluent Fate of sulfamethoxazole, 4-nonylphenol, and 17β-estradiol in groundwater contaminated by wastewater treatment plant effluent
Organic wastewater contaminants (OWCs) were measured in samples collected from monitoring wells located along a 4.5-km transect of a plume of groundwater contaminated by 60 years of continuous rapid infiltration disposal of wastewater treatment plant effluent. Fifteen percent of the 212 OWCs analyzed were detected, including the antibiotic sulfamethoxazole (SX), the nonionic surfactant...
Authors
Larry B. Barber, Steffanie H. Keefe, Denis R. LeBlanc, Paul M. Bradley, Francis H. Chapelle, Michael T. Meyer, Keith A. Loftin, Dana W. Koplin, Fernando Rubio
Comparison of pumped and diffusion sampling methods to monitor concentrations of perchlorate and explosive compounds in ground water, Camp Edwards, Cape Cod, Massachusetts, 2004-05 Comparison of pumped and diffusion sampling methods to monitor concentrations of perchlorate and explosive compounds in ground water, Camp Edwards, Cape Cod, Massachusetts, 2004-05
Laboratory and field tests were conducted at Camp Edwards on the Massachusetts Military Reservation on Cape Cod to examine the utility of passive diffusion sampling for long-term monitoring of concentrations of perchlorate and explosive compounds in ground water. The diffusion samplers were constructed of 1-inch-diameter rigid, porous polyethylene tubing. The results of laboratory tests...
Authors
Denis R. LeBlanc, Don A. Vroblesky
Distribution and migration of ordnance-related compounds and oxygen and hydrogen stable isotopes in ground water near Snake Pond, Sandwich, Massachusetts Distribution and migration of ordnance-related compounds and oxygen and hydrogen stable isotopes in ground water near Snake Pond, Sandwich, Massachusetts
Explosive compounds, such as RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) and HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine), and the propellant compound perchlorate are present in ground water near Snake Pond, a ground-water flow-through glacial kettle pond in the glacial sand and gravel aquifer on western Cape Cod near Camp Edwards on the Massachusetts Military Reservation...
Authors
Denis R. LeBlanc, Andrew J. Massey, Jessica J. Cochrane, Jonathan H. King, Kirk P. Smith
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government