Resume / CV

Summary

Jeffrey D. Walker, PhD is an environmental data scientist, water resources engineer, and full-stack web developer specializing in web-based databases, models, and data visualization tools in addition to hydrologic and water quality data collection, analysis, and modeling.

Technical Skills

Data Science: Software development for scientific analysis and modeling (R, tidyverse, Python), R package development, reproducible research environments (RMarkdown, Quarto, Jupyter), source code version control (git), machine learning and AI modeling, geospatial data analysis and processing, large-scale database management and cloud computing platforms, and automated data processing pipelines.

Full-stack Web Development: Database design and implementation (PostgreSQL), cloud infrastructure (AWS, GCP, Azure), modern frontend web application development (JavaScript, Vue.js), advanced data visualization libraries for scientific applications (D3, Leaflet), geospatial platforms (PostGIS , ESRI ArcGIS), RESTful API development and server-side architecture (Express, Django), continuous integration and deployment (CI/CD) pipelines, application containerization (Docker), and serverless infrastructure.

Water Resources Engineering: Hydrologic and water quality modeling across multiple scales from local watersheds to regional systems, watershed management and climate change impact assessment, development and calibration of both mechanistic process-based models and statistical models, stream ecology and thermal habitat modeling, and integration of field monitoring data with predictive modeling frameworks.

Education

Tufts University, School of EngineeringMedford, MA
Doctor of Philosophy, Environmental and Water Resources Engineering2010 – 2014
Massachusetts Institute of TechnologyCambridge, MA
Master of Engineering, Environmental and Water Resources Engineering2006 – 2007
Cornell University, College of Agriculture and Life SciencesIthaca, NY
Bachelor of Science, Science of Earth Systems2001 – 2006

Professional Experience

Walker Environmental Research, LLCBrunswick, ME
Environmental Data Scientist, Water Resources Engineer, Full-stack Developer2010 – present

Environmental data science and engineering specializing in the development of web-based databases, models, and data visualization tools as well as hydrologic and water quality data collection, analysis, modeling, and visualization. Clients include state, tribal and federal government agencies, universities, private firms, and non-profit organizations.

Federico & Associates, IncWest Palm Beach, FL
Water Resources Engineer and Web Developer2016 – present

Water quality modeling and data analysis to support industry compliance with environmental regulations and permits, design and operation of water quality treatment systems, and development of automated water quality compliance tracking systems.

CDM SmithCambridge, MA
Water Resources Engineer2007 – 2010

Water resources engineering focusing on water quality and water supply modeling, water resources systems analysis, and watershed planning and management.

Academic Experience

Dept. of Environmental Conservation, UMass AmherstAmherst, MA
Post-doctoral Researcher2015 – 2016

Development of the Spatial Hydro-ecological Decision System (SHEDS), a collection of web applications, interactive data visualizations, and database systems designed to improve environmental decision making.

HydroSystems Research Group, UMass AmherstAmherst, MA
Post-doctoral Researcher2014 – 2015

Web application development to assess climate change vulnerability of water resources systems.

Web-Based Projects

See the Projects page for detailed descriptions.

Reports

Walker, J.D. (2025). The Flow Photo Explorer: Low-cost Environmental Monitoring using Timelapse Imagery and a Deep Learning Model. Year 2 Final Report, USEPA Regional-ORD Applied Research Program (ROAR) Project #2554. Prepared for US Environmental Protection Agency Office of Research and Development. July 25, 2025. https://doi.org/10.5281/zenodo.20885892

Walker, J.D. (2025). Low-cost Streamflow Monitoring using Timelapse Imagery and Machine Learning Models. Year 1 Final Report, USEPA Regional-ORD Applied Research Program (ROAR) Project #2554. Prepared for US Environmental Protection Agency Office of Research and Development. April 3, 2025. https://doi.org/10.5281/zenodo.15133342

Walker, J.D. (2023). A Regional Stream Temperature Model for Assessing Climate Change Impacts on Thermal Habitat in Massachusetts. Technical report prepared for Massachusetts Division of Fisheries and Wildlife (MassWildlife). July 13, 2023. https://doi.org/10.5281/zenodo.8145195

Walker, J.D. and J. Kann (2022). Spatial and Temporal Nutrient Loading Dynamics in the Sprague River Basin, OR, Water Years 2002 – 2020. Technical Report prepared for the Klamath Tribes Natural Resources Department. 114 pp + Appendices. https://doi.org/10.5281/zenodo.7377353

Walker, J.D., and J. Kann (2022). Water and Nutrient Balances of Upper Klamath Lake, Water Years 1992–2018. Technical Report prepared for the Klamath Tribes Natural Resources Department, Chiloquin, OR. 80 pp + Appendices. https://doi.org/10.5281/zenodo.6607800

Walker, J.D. and J. Kann (2020). Inflow/outflow phosphorus loading dynamics in Upper Klamath Lake, Oregon. Technical Report prepared for U.S Fish and Wildlife Service, Klamath Falls Fish and Wildlife Office. November 2020. https://doi.org/10.5281/zenodo.6628410

Walker, J.D. (2019). Spy Pond Stormwater Capture Feasibility Study. Prepared for Mystic River Watershed Association and Arlington, Belmont and Cambridge Stormwater Flood Board. October 2019. https://doi.org/10.5281/zenodo.6524907

Walker, J.D. (2018). A Method for Estimating the Daily and Total Herring Run Size on the Mystic River Using Video Counts. Prepared for Mystic River Watershed Association. May 1, 2018.

Walker, J.D. (2018). A Comparison of Video and Volunteer Fish Count Data for Estimating the 2017 Herring Run Size on the Mystic River. Prepared for Mystic River Watershed Association. March 26, 2018.

Walker, J.D. (2017). Development of Real-time Bacteria Exceedance Models for the Mystic River Recreational Flagging Project. Prepared for Mystic River Watershed Association. October 24, 2017.

Durant, J.L., Jacobs, B., Walker, J.D., Shanahan, P., and J.F. Knott (2017). Modeling N-Nitrosodimethylamine and Trichloroethylene Concentrations in the Wilmington, Massachusetts Water Supply System: 1974 to 2000. Prepared for Massachusetts Department of Public Health. July 6, 2017.

Walker, J.D. (2016). Malden River: Exploratory Water Quality Data Prepared for the Mystic River Watershed Association by Jeffrey D. Walker PhD, Walker Environmental Research LLC. August 9, 2016.

Walker, J.D., Kann, J., and W.W. Walker (2015). Spatial and temporal nutrient loading dynamics in the Sprague River Basin, Oregon. Prepared by Aquatic Ecosystem Sciences, J. D. Walker, and W. W. Walker for the Klamath Tribes Natural Resources Department. 73 pp. + appendices.

Walker, J.D., and C. Brown (2015). An R Package and Web Application for Performing a Climate Stress Test. Prepared for U.S. Army Corps of Engineers. August 2015.

Walker, W.W., and J.D. Walker (2014). Trends in Total Phosphorus Concentration and Flow at Monitoring Sites Within and Upstream of Everglades National Park. Prepared for U.S. Department of the Interior.

Walker, W.W., and J.D. Walker (2013). Analysis of Fecal Coliform Data from Onondaga Lake Tributaries. Prepared for Upstate Freshwater Institute and Onondaga County Department of Water Environment Protection.

Walker, W.W., Walker, J.D., and J. Kann (2012). Evaluation of Water and Nutrient Balances for the Upper Klamath Lake Basin in Water Years 1992-2010. Technical Report to the Klamath Tribes Natural Resources Department, Chiloquin, OR. 50 pp + Appendices.

Beresin, G., Crossley, L., Gareau, G., Jiang, Y., Olson, K., Sexton, A., Walker, J., Wu, R., and Zhao, S. (2012). Stormwater Management in the Aberjona River. Report for the 2012 Water: Systems, Science + Society (WSSS) Practicum. Prepared for The Mystic River Watershed Association and Tufts University Department of Urban + Environmental Policy + Planning. May 2012.

Walker, W.W., and J.D. Walker (2011). Trends in Onondaga Lake Nearshore Monitoring Data. Onondaga Lake Ambient Monitoring Program – 2011 Report. Prepared for Ecologic, LLC & Onondaga County Department of Water Environment Protection.

Publications

Goodling, P., Fair, J., Gupta, A., Walker, J., Dubreuil, T., Hayden, M., and Letcher, B. (2025). Technical note: A low-cost approach to monitoring streamflow dynamics in small, headwater streams using timelapse imagery and a deep learning model. Hydrology and Earth System Sciences. 29, 6445–6460. doi: 10.5194/hess-29-6445-2025.

Shank B., Miller A.S., Solinger L., Asaro M.J., Sigourney D., Huamani A., Trego M.L., Franco C., Roberts J.J., Walker J.D., Price A.L., Duffing Romero M.D., Coogan C., Goebel J., Cole T.V.N. and S.A. Hayes (2025). A decision support tool for assessing entanglement risk to protected species from fixed-gear fisheries with applications to North Atlantic right whales (Eubalaena glacialis) in the Northwest Atlantic. Frontiers in Marine Science. 12: 1549345. doi: 10.3389/fmars.2025.1549345

Gupta, A., Chang, T., Walker, J., and B. Letcher (2022). Towards Continuous Streamflow Monitoring with Time-Lapse Cameras and Deep Learning. In ACM SIGCAS/SIGCHI Conference on Computing and Sustainable Societies (COMPASS ’22). Association for Computing Machinery, New York, NY, USA, 353–363. doi: 10.1145/3530190.3534805

Walker, J. D., Letcher, B. H., Rodgers, K. D., Muhlfeld, C. C., & D’Angelo, V. S. (2020). An Interactive Data Visualization Framework for Exploring Geospatial Environmental Datasets and Model Predictions. Water, 12(10), 2928. doi: 10.3390/w12102928

Kann, J., and J.D. Walker (2020). Detecting the effect of water level fluctuations on water quality impacting endangered fish in a shallow, hypereutrophic lake using long-term monitoring data. Hydrobiologia 847, 1851–1872. doi: 10.1007/s10750-020-04215-z

Letcher, B. H., Walker, J. D., O’Donnell, M. J., Whiteley, A. R., Nislow, K. H., & Coombs, J. A. (2018). Three Visualization Approaches for Communicating and Exploring Passive Integrated Transponder Tag Data. Fisheries, 43(5), 241–248. doi: 10.1002/fsh.10067

Asarian, J. E., and J.D. Walker (2016). Long-Term Trends in Streamflow and Precipitation in Northwest California and Southwest Oregon, 1953-2012. J. of the American Water Resources Association, 52(1): 241–261. doi: 10.1111/1752-1688.12381

Whateley, S., Walker, J.D., and C. Brown (2015). A web-based screening model for climate risk to water supply systems in the northeastern United States. Environmental Modelling & Software, 73: 64–75. doi: 10.1016/j.envsoft.2015.08.001

Walker, J.D., and S.C. Chapra (2014). A client-side web application for interactive environmental simulation modeling. Environmental Modelling & Software, 55: 49–60. doi: 10.1016/j.envsoft.2014.01.023

Howarth, R.W., Hayn, M., Foreman, K., Marino, R., McGlathery, K., Berg, P., Giblin, A., and J.D. Walker (2014). Metabolism of a nitrogen-enriched coastal marine lagoon during the summertime. Biogeochemistry 118 (1-3): 1–20. doi: 10.1007/s10533-013-9901-x

Walker, J.D., Walter, M.T., Parlange, J.-Y., Rose, C.W., Tromp-van Meerveld, H.J., Gao, B., and A.M. Cohen (2007). Reduced raindrop-impact driven soil erosion by infiltration. Journal of Hydrology 342 (3-4): 331–335. doi: 10.1016/j.jhydrol.2007.06.003

Parasiewicz, P. and J.D. Walker (2007). Comparison of MesoHABSIM with two micro-habitat models (PHABSIM and HARPHA). River Research and Applications 23 (8): 904–923. doi: 10.1002/rra.1043

Conference Proceedings

Starosta, L.E., Westphal, K.S., and J.D. Walker (2011). Simple Management Tools to Reduce Water Pumping Based on Hydrologic Probabilities and Supply Shortage Risk Quantification. Conference Proceedings of the American Society of Civil Engineers (ASCE) Environment and Water Resources Institute (EWRI) World Environment and Water Resources Congress 2011: Bearing Knowledge for Sustainability. Palm Springs, CA. May 22, 2011.

Walker, J.D., Rees, P.S. and T.K. Walsh (2009). The Importance of Instream Hydraulics in River Water Quality Models: Lessons from the Blackstone River. Oral presentation and publication in the Conference Proceedings of the American Society of Civil Engineers (ASCE) Environment and Water Resources Institute (EWRI) World Environment and Water Resources Congress 2009: Great Rivers. Kansas City, MO. May 19, 2009.

Lefkowitz, J., Westphal, K., Walker, J., and G. Mercer (2009). The Economic and Environmental Significance of Nonpoint Source Abatement in Large Watersheds. Conference Proceedings of the ASCE-EWRI World Environment and Water Resources Congress 2009: Great Rivers. Kansas City, MO. May 19, 2009.

Presentations

Walker, J.D., Knight, R., and B. Letcher (2019). An Interactive Data Visualization Tool for Exploring the Causes and Extent of Streamflow Alteration across the Lower Mississippi and Gulf Coast Region. Mississippi Water Resources Conference: Jackson, MS. April 3, 2019.

Walker, J.D., and B. Letcher (2016). A Web-based System for Managing, Analyzing, and Visualizing Stream Temperature Data across New England. Maine Sustainability and Water Conference. Augusta, ME. March 29, 2016.

Kaczor, K., and J.D. Walker (2016). Informing Beach Advisories: Using Data Visualization Techniques to Explore and Better Understand the Maine Healthy Beaches Dataset. Maine Sustainability and Water Conference. Augusta, ME. March 29, 2016.

Walker, J.D. (2014). Interactive and Web-based Approaches to Environmental Modeling. 2014 UCOWR-NIWR-CUAHSI Conference. Medford, MA. March 28, 2014.

Kennedy, L., Herron, P., and J. Walker (2014). Collaborative Planning for Green Infrastructure in the Mystic River Watershed. 2014 NEWEA Annual Conference. Boston, MA.

Walker, J., Beresin, G., Crossley, L., Jiang, Y., Olson, K., Zhao, S., Gareau, G., Sexton, A., Wu, R., Russell, R., and Vogel, R. (2012). A GIS-based Approach to Identify Priority Locations for Stormwater Best Management Practices in the Aberjona River Watershed. The 2012 WSSS Interdisciplinary Water Symposium, The Glass Half Full: Valuing Water in the 21st Century. Awarded First Prize in Student Poster Competition.

Professional Activities

Maine Thermal Infrared (TIR) Imagery Data Management Workgroup2026 - present
Maine Water Temperature Working Group, Coordinator2018 - present
Maine State Wildlife Action Plan (SWAP), Freshwater Aquatic Habitats Subcommittee2025
Trout Unlimited, Merrymeeting Bay Chapter — Technical Advisor2023 – 2024
Gulf of Maine Research Institute — Technical Advisory Committee, EdTech, LabVenture Program2017 – 2018
Maine Healthy Beaches — Technical Advisory Committee, Subcommittee on New U.S. EPA Beach Action Value (BAV) Recommendations2015 – 2016

Clients

  • 2026 – present Conservation Science Partners
  • 2026 – present NH Dept. of Environmental Services (Fuss & O'Neill)
  • 2025 – present Atlantic Salmon Federation
  • 2025 – present MT Fish, Wildlife & Parks and University of Montana
  • 2024 – present National Park Service, South Florida Natural Resources Center
  • 2024 – present Penobscot Indian Nation
  • 2024 – present U.S. Geological Survey, Northern Rocky Mountain Science Center
  • 2021 – present University of Alaska, Anchorage
  • 2021 – present U.S. Geological Survey, Lower Mississippi-Gulf Water Science Center
  • 2019 – present NOAA Fisheries, Northeast Fisheries Science Center (TechGlobal, IBSS)
  • 2018 – present U.S. Geological Survey, Eastern Ecological Science Center
  • 2014 – present Mystic River Watershed Association
  • 2010 – present U.S. Dept of Interior, Bureau of Indian Affairs (Aquatic Ecosystem Sciences, LLC)
  • 2026 Lake Winnipesaukee Alliance (FB Environmental)
  • 2022 – 2026 U.S. Environmental Protection Agency, Region 1 (CEI)
  • 2024 – 2025 U.S. Environmental Protection Agency, Office of Research and Development
  • 2024 Tova
  • 2023 – 2024 National Fish and Wildlife Federation (Aquatic Ecosystem Sciences, LLC)
  • 2023 Piscataqua Region Estuaries Partnership (FB Environmental)
  • 2023 MA Div. of Fish and Wildlife
  • 2021 – 2022 MassBays (CEI, Hodge Water Resources)
  • 2020 – 2022 Klamath Tribes (Aquatic Ecosystem Sciences, LLC)
  • 2020 – 2021 National Geographic Society (Conservation Science Partners)
  • 2020 – 2021 U.S. Dept of Agriculture, Forest Service
  • 2019 – 2021 U.S. Fish and Wildlife Service (Aquatic Ecosystem Sciences, LLC)
  • 2019 – 2021 U.S. Environmental Protection Agency, Region 1 (Horsley Witten Group, FB Environmental)
  • 2018 – 2019 UMass Amherst, Dept of Environmental Conservation
  • 2018 Alberta Environment and Parks
  • 2017 – 2019 U.S. Environmental Protection Agency, Region 1 (ERG Inc)
  • 2016 – 2017 U.S. Geological Survey, Northern Rocky Mountain Science Center
  • 2016 – 2017 MA Dept. of Public Health (John Durant, PE, PhD)
  • 2016 U.S. Fish and Wildlife Service (North Atlantic Salmon Federation)
  • 2016 U.S. Geological Survey, Conte Anadromous Fish Lab and University of Massachusetts, Amherst (Hodge.WaterResources, LLC)
  • 2014 – 2016 National Marine Fisheries Service (Kier Associates)
  • 2012 – 2016 U.S Dept of Interior and U.S. Environmental Protection Agency (William W. Walker, Jr, PhD)
  • 2015 CDM Smith, Inc
  • 2015 Columbia Habitat Monitoring Program (South Fork Research, Inc)
  • 2014 – 2015 Klamath Tribes Natural Resources Dept. (Aquatic Ecosystem Sciences, LLC)
  • 2011 – 2015 Onondaga County Dept of Environmental Protection (William W. Walker, Jr, PhD)
  • 2014 National Oceanic and Atmospheric Administration (Riverbend Sciences and Kier Associates)

Names in parentheses denote primary contractor.