John Callahan joined the staff of the Delaware Geological Survey in February 2008. Dr. Callahan brings to the DGS a combination scientific knowledge and technical skills. John's scientific background is in the areas of climatology/meteorology, atmospheric science, storm surge/tides, and land-surface physical geography, with an emphasis on techniques in remote sensing/lidar and (time series and spatial geoprocessing) statistical data analysis. John has taught courses, workshops, and given class presentations in meteorology, climate, GPS/GIS, and remote sensing. He holds B.Sc. degrees in Physics and Mathematics from Temple University, M.Sc. degree in Geography from UD, and a PhD in Climatology from UD.
John's current research focuses on natural hazards that impact Delaware and the Mid-Atlantic region, particularly coastal storms and inundation from storm surge/tides, sea-level rise, severe weather, watershed inland hydrology, and droughts. Projects of particular interest include coastal flooding trends in the Delaware and Chesapeake Bays, quantifying uncertainties in lidar-based elevation in coastal marshes, the Delaware Coastal Flood Monitoring System (www.coastal-flood.udel.edu), an online early warning system for coastal storms. John provides guidance to state and local gov't agencies in real-time during severe weather events and for long-term planning in regard to sea-level rise, climate change, environmental monitoring, and national reports/guidance. Additionally, at DGS John maintains the DGS web sites and public data distribution mechanisms, such as web mapping services, Delaware Geologic Information Resource (DGIR), and the Delaware Water Conditions Report.
Prior to joining the DGS, John was the lead GIS Coordinator for UD, where he built numerous web mapping applications, worked on a variety of geospatial and statistical analysis projects, and developed and taught many GIS-related and web development workshops. During this time, John was one of of the original team members, and lead developer, that created the Delaware Data Mapping and Integration Laboratory (DataMIL) in 2002, an online data sharing and mapping system for "framework" datasets within Delaware. For this work, the team received the ESRI Special Achievement in GIS (SAG) award in 2002, the USGS John Wesley Powell Award in 2003, and John presented (along with his wife Tina) DataMIL to over 12,000 attendees during the opening plenary session of the ESRI International User Conference. In addition to the DataMIL, John has contributed to several statewide GIS activities (including managing the Delaware Metadata Clearinghouse, and chair of the GIS Conference committees in 2003 and 2004) and was subsequently the recipient of the 2007 Delaware State Geographic Service Award.
Current service activities:
US Climate Variability and Predictability Program (CLIVAR) Predictability, Predictions, and Applications Interface (PPAI) Panel
Delaware River Basin Commission (DRBC) Advisory Committee on Climate Change (ACCC)
Geospatial Science and Technology (GST) Career & Technical Education High School Pathway Advisory Committee
Delaware State Hazard Mitigation Council
Delaware Resilient and Sustainable Communities League (RASCL)
DelawareView (Delaware chapter of AmericaView)
Provide real-time guidance to state, county, local agencies during severe weather events
Provide planning guidance to state agencies on climate change and sea-level rise
Recognition and Awards
UD Department of Geography and Spatial Sciences Research Award, 2021
GSA/AASG John C. Frye Memorial Award for Environmental Geology, 2019
Delaware State Geographic Service Award, 2007
USGS John Wesley Powell Award, 2003
ESRI Special Achievement in GIS (SAG) Award, 2002
Research Data Management Services (RDMS) Graduate Fellowship, University of Delaware, 1998
UD Department of Physics and Astronomy, Teaching Award, 1995
Outstanding Physics Graduate Award, Department of Physics, Temple University, 1994
Outstanding Achievement Scholarship (OAS), Full tuition, Temple University, 1989
Selected publications (refer to CV for complete list):
Stotts, Stephanie, Olivia Gulledge, and John Callahan, 2021 (in press). Impact of Channel Dredging on the Climate-Growth Relationship in a Mid-Atlantic White Cedar (Chamaecyparis thyoides L. (B.S.P.)) Freshwater Tidal Wetland, Journal of Coastal Research.
Callahan, John A., and Daniel J. Leathers, 2021 (in review). Estimation of Return Levels for Extreme Skew Surge Coastal Flooding Events in the Delaware and Chesapeake Bays for 1980 – 2019. Frontiers in Climate: Climate Risk Management.
Callahan, John A., Daniel J. Leathers, and Christina L. Callahan, 2021 (in review). Skew Surge and Storm Tides of Tropical Storms in the Delaware and Chesapeake Bays for 1980- 2019. Frontiers in Climate: Climate Risk Management (invited to special collection on Coastal Flooding: Modeling, Monitoring, and Protection Systems).
Brinson, Kevin R., Daniel L. Warner, and John A. Callahan, 2021. Determination of Flood Elevations and Hydrology of Delaware Roadways. Tech Report, Delaware Department of Transportation, 23 pp.
McKenna, Thomas E., John A. Callahan, Catherine L. Medlock, and Naomi S. Bates (2018). Creation of Improved Accuracy LiDAR-Based Digital Elevation Models for the St. Jones River and Blackbird Creek Watersheds. Technical Report prepared for the Delaware Department of Natural Resources and Environmental Control (DNREC) Delaware Coastal Programs, 37 pp.
Callahan, John and Naomi Bates (2018). Development of Delmarva Fox Squirrel Habitat Maps from LiDAR Data for Sussex County, Delaware. Technical Report prepared for the Delaware Department of Natural Resources and Environmental Control (DNREC) Division of Fish and Wildlife, 20 pp.
Callahan, John A., Benjamin P. Horton, Daria L. Nikitina, Christopher K. Sommerfield, Thomas E. McKenna, and Danielle Swallow (2017). Recommendation of Sea-Level Rise Planning Scenarios for Delaware: Technical Report prepared for Delaware Department of Natural Resources and Environmental Control (DNREC) Delaware Coastal Programs, 115 pp.
Abdolali, A., Guiteras, S., Callahan, J., Kirby, J.T., Shi, F. and Mitchell, L. (2016) Vegetation bias correction in tidal salt marsh LiDAR data sets with artificial neural networks. Restore America’s Estuaries 8th National Summit on Coastal and Estuarine Restoration and 25th Biennial Meeting of The Coastal Society, December 10-15, 2016 New Orleans, LA, USA.
Callahan, John (2015). Analysis of Storm Surge and Tidal Data Relationships in the Delaware Inland Bays based on Meteorological Conditions, Technical Report to DNREC Delaware Coastal Programs, 38 pp.
Tehranirad, Babak, Banihashemi, Saeidah, Kirby, James T., Callahan, John A. and Shi, Fengyan (2014). Tsunami Inundation Mapping for Ocean City, MD NGDC DEM, Research Report No. CACR-14-04, Center for Applied Coastal Research, Department of Civil and Environmental Engineering, University of Delaware. 58 pp.
Samoteskul, K., Firestone, J., Corbett, J., Callahan, J. (2014). Changing Vessel Routes Could Significantly Reduce the Cost of Future Offshore Wind Projects, Journal of Environmental Management, Volume 141, Pages 146–154.
Bates, A., Samoteskul, K., Callahan, J., Corbett, J., Kempton, W., Madsen, J., Shriver, G., Dvorak, M., Kenney, R., McCormack, R., Harris, K. Noel, L., and Firestone, J. (2012). Delaware Marine Spatial Planning: Offshore Wind Context. Final Report. Center for Carbon-free Power Integration.
Madsen, J., A. Bates, J. Callahan and J. Firestone (2011). Use of Geospatial Data in Planning for Offshore Wind Development. Geospatial Techniques for Managing Environmenal Resources. J. K. Thakur, Singh, S.K., Ramanathan, A., Prasad, M.B.K., Gossel, W. . Heidelberg, Germany, Springer and Capital publication.
Angelia S. M. Vanderlaan, James J. Corbett, Shannon L. Green, John A. Callahan, Chengfeng Wang, Robert D. Kenney, Christopher T. Taggart, and Jeremy Firestone (2009). Probability and Mitigation of Vessel Encounters with North Atlantic Right Whales, Endangered Species Research, Vol 6, p. 273-285, March 2009.
Chengfeng Wang, John Callahan, and James Corbett (2007). Geospatial Modeling of Ship Traffic and Air Emissions, Proceedings of the ESRI International User Conference, June 2007.
DeLiberty, Tracy L., and John A. Callahan (2001), Diurnal Variability of Satellite Derived Precipitable Water in the Amazon Basin, Proceedings of the 11th Conference on Satellite Meteorology and Oceanography, American Meteorological Society. Madison, Wisconsin, Oct. 15-18, p. 196-199.
Deliberty, T.L., J.A. Callahan, A.R. Guillory, and G.J. Jedlovec (2000). A Regional Scale Assessment of Satellite-Derived Precipitable Water in the Amazon Basin. Preprints, 10th Conference on Satellite Meteorology and Oceanography, Long Beach, CA, Amer. Meteor. Soc., 414-417.
First State Geology
Callahan, John (2011), DGS Unveils New Website and Web-Mapping Services, First State Geology, Delaware Geological Survey Newsletter, Vol 28, No. 1, Winter Edition, p. 2.
Callahan, John (2011), Prototype Coastal Flood Monitoring System for Delaware, First State Geology, Delaware Geological Survey Newsletter, Vol 28, No. 1, Winter Edition, p. 3.
Callahan, John (2011), DataMIL Gets a New Look, First State Geology, Delaware Geological Survey Newsletter, Vol 28, No. 1, Winter Edition, p. 4.
Callahan, John (2002), Delaware: A National Map Pilot Project, First State Geology, Delaware Geological Survey Newsletter, Vol 20, No. 1, Winter Edition. p. 2.
Selected Invited Presentations and Panels
Solve Climate by 2030: A Global Dialog – Delaware, Panel Session. Bard College Center for Environmental Policy, April 2021.
Sea-Level Rise Projections and Impacts on Delaware. University of Delaware, College of Earth, Ocean, and Environment and Delaware Sea Grant, Coast Day, October 2020.
Hurricanes, Sea-Level Rise, and Coastal Flooding in the Mid-Atlantic. University of Delaware, College of Earth, Ocean, and Environment Ocean Currents Lecture Series, September 2020.
Climate Change and Sea-Level Rise: Observations and Projections for the State of Delaware. NOAA Community Climate Adaptation Planning Training, St. Jones Reserve, Dover, DE, January 2019.
High Tide in Dorchester Documentary Screening. Guest Panelist, Earth Ocean and Environment Club UD, Newark, DE, November, 2018.
Determination of Future Sea-Level Rise Planning Scenarios for Delaware. 110th Annual Meeting of the Association of American State Geologists, Rehoboth Beach, DE, June 2018.
LiDAR Vertical Bias Estimation and DEM Correction in a Tidal Salt Marsh. 110th Annual Meeting of the Association of American State Geologists, Rehoboth Beach, DE, June 2018.
Storms, Climatology, and Changing Conditions in Delaware, Guest Panelist at the Delaware Resilient and Sustainable Communities League (RASCL) Summit, Dover, DE, November 2017.
Past Observations and Future Projections of Climate in Delaware, Guest Speaker at the Delaware March for Science and Our Earth, Newark, DE, April 2017.
Delaware Coastal Flood Monitoring System, Delaware River Basin Commission Flood Advisory Committee, Trenton, NJ, May 2016.
The Delaware Coastal Flood Monitoring System, MACRI Coastal Flooding Workshop, Clayton Hall Conference Center, Newark, DE, September 2015.
Monitoring Severe Weather and Flooding in Delaware's Environment, Army Reserve Force Policy Committee (ARFPC), Bethany Beach National Guard Training Site, September 2015.
GIS Portals and Web Mapping Services, Guest panelist, Northeast Map Organization (NEMO) Annual conference, New York, NY, June 2007.
Status of Geographic Information Systems in Delaware, Center for Remote Sensing Seminar Series, University of Delaware, Newark, DE, November 2002.
The Delaware DataMIL, Plenary presentation at the ESRI User Conference plenary (12,000+ attendees), San Diego, CA, July 2002.
The Delaware Data Mapping and Integration Laboratory (DataMIL), Plenary presentation at the Delaware State GIS Conference, Rehoboth Beach, DE, April 18, 2002.
The State of GIS in Delaware, University of Delaware, Department of Geography Seminar Series, February 15, 2002.
Selected projects (refer to CV for complete list):
Co-Principal Investigator, "Assessing spatial distributions of soil carbon stocks and their vulnerability to sea level rise in tidal marsh ecosystems", Delaware National Estuarine Research Reserve (DNERR), November 2019 - March 2021.
Co-Principal Investigator, "Determination of Flood Elevations and Hydrology of Delaware Roadways", Delaware Department of Transportation, March 2020 - October 2020.
Principal Investigator, "Storm Surge and High Tide Relationships in Development of a Delaware Inland Bays Coastal Flood Warning System", DNREC Delaware Coastal Programs, October 2019 - March 2021.
Co-Principal Investigator, "Morphology and Tidal Inundation of Tidal Wetlands in the Delaware Estuary", Delaware Sea Grant, February 2018 - January 2020.
Principal Investigator, "Development of a Coastal Storm Hazard Early Warning and Decision Support Dashboard for Delaware: Integration and Analysis of Past Coastal Storms", Delaware Sea Grant, October 2017 - March 2018.
Principal Investigator, "Digital Elevation Model, GIS, and Watershed Analysis to Support USGS StreamStats Update", Delaware Department of Transportation, July 2017 - December 2018.
Principal Investigator, "Determination of Future Sea-Level Rise Planning Scenarios and Development of Coastal Inundation Maps for the State of Delaware", DNREC Delaware Coastal Programs, June 2015 - September 2016.
Principal Investigator, "Development of a High Water Mark Database and Display System for Coastal Flooding Events in Delaware", Delaware Sea Grant, February 2014 - July 2016.
Co-Principal Investigator, "Modeling Tsunami Inundation and Assessing Tsunami Hazards for the US East Coast", NOAA National Tsunami Hazard Mitigation Program (NTHMP), August 2010 – July 2013.
Principal Investigator, "A Web-Delivered Application for Hydrogeologic Data", Delaware Department of Natural Resources and Environmental Control (DNREC), Water Supply Section, July 2010 – December 2011.
Co-Principal Investigator, "Offshore Wind Power for Delaware in a Marine Spatial Planning Context", Delaware Sea Grant Program, February 2011 - February 2012.
Co-Principal Investigator, "A Prototype Coastal Flood Monitoring System for Delaware", Joint funding from Delaware NSF EPSCoR and Delaware Department of Environmental Control (DNREC), July 2009 – July 2010.