integrated hydrology at princeton

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Reed Maxwell
Reed Maxwell
Professor Civil and Environmental Engineering and the High Meadows Environmental Institute
Director Integrated Groundwater Modeling Center
Princeton University

Summary Bio Reed Maxwell is a Professor in Civil and Environmental Engineering (CEE) and the High Meadows Environmental Institute (HMEI) at Princeton University. He also directs the Integrated GroundWater Modeling Center (IGWMC). His research interests are focused on understanding connections within the hydrologic cycle and how they relate to water quantity and quality under anthropogenic stresses. He was the 2020 Henry Darcy Distinguished Lecturer, an elected Fellow of the American Geophysical Union, was the 2018 Boussinesq Lecture and the 2017 School of Mines Research Award recipient. He has authored more than 160 peer-reviewed journal articles and teaches classes on hydrology and fluid mechanics. At Princeton he currently leads a research group of graduate students, postdoctoral researchers and staff housed within CEE and HMEI. Over his career he has collaborated with and mentored 16 PhD students and 18 MS thesis students. Prior to coming to Princeton, he was faculty at the Colorado School of Mines and a postdoc and then staff in the Hydrologic Sciences group at Lawrence Livermore National Laboratory. He holds a PhD degree in Environmental Water Resources from the Civil and Environmental Engineering Department at the University of California, Berkeley.

Tweets by @reedh2o



My research is interdisciplinary in nature and is focused on a range of water-related questions. My emphasis is usually the development and application of numerical models to study interfaces in hydrology, but there is also a significant field component to my work. My interests span a variety of hydrology, water resources and water quality topics including: surface water and the terrestrial hydrologic cycle; interactions of the land-surface, surface water and groundwater, and the atmosphere; human health risk assessment; and reactive contaminant transport and geochemical cycling.

The application of numerical models to water resources problems, with their inherent complications, is difficult. Because of this, my group develops models that draw on novel numerical methods and parallel or high-performance computing. My work is collaborative and I pursue lines of inquiry that transcend scientific and disciplinary boundaries by using models to understand and bridge scales and processes. I have a fantastic research group and they are critical to the projects the reason for the successes you see here.

Selected Current Research Projects and Themes

HydroFrame: A national community hydrologic modeling framework for scientific discovery

We don't know how much freshwater we have on Earth nor do we know how fast it is being replenished. Finding the answer to this fundamental question wil require the combination of models, observations and other theory and products. HydroFrame is a project to make national hydrologic simulations more accessible. We are building tools so that you can rapidly subset, run and share hydrologic models of any watershed in the US all in the cloud. HydroFrame is intended to bring the hydrologic community together to help answer some of these fundamental questions.

HydroGEN: A physically rigorous, machine learning platform for hydrologic scenario generation in a no-analog future

HydroGEN is a platform for hydrologic simulation that places the power of integrated hydrologic models in the hands of water managers and decision makers. We train machine learning emulators on advanced physically based hydrologic simulations. This allows our users to generate custom hydrologic scenarios which are both physically rigorous and computationally efficient. By leveraging both physical models and observations we can provide scenarios of what happens to our planet's resources when we are off the road map. Users will be able to rapidly and easily explore the potential for changing conditions and unprecedented events, which are difficult for machine learning approaches trained only on past behavior to capture on their own. Furthermore, most scientifically rigorous scenarios are generated at the national and global scale leaving local users with little control to modify or explore their particular area of interest. Our platform is focused on providing customizable scenarios so that individual users can generate exactly what they need to inform their own critical decisions. Users are able to customize their spatial area and metrics of interest as well as design the historical or future scenarios they would like to explore. Our platform goes well beyond just streamflow and is designed to provide spatially distributed simulations of complete watershed systems including groundwater, soil moisture, streamflow and plant water use. We understand that decision makers require transparency and reliability in any tool they use. Therefore, our platform will include model exploration tools that provide explainable AI, as well as metric and scenario exploration. Users do not need to be machine learning experts. Our tools are designed to let them focus on the variables and metrics that are of interest to them and not the mechanics of the modeling. The World's future problems are substantial, but modern tools can help. HydroGEN is a tool to put better water information in the hands of decision makers. Supported by the US National Science Foundation Convergence Accelerator Program.


Understanding water fluxes in an emblematic headwaters watershed

The East River catchment is a representative headwater basin of the Colorado River, which in turn supplies the Southwest United States with water for energy, irrigation, and municipal use. Given that 85% of streamflow is generated in small, topographically-complex basins, more research is needed to understand nutrient and water cycling in these regions. The Maxwell group contributes to the larger Department of Energy Scientific Focus Area by developing and testing integrated models of the catchment at multiple scales and maintaining multiple meteorological towers to validate simulations. Our interdisciplinary team merges field observations, model development, and climate change studies to better understand water availability for the Western United States. Current work includes improving the snow formulation of the ParFlow-CLM model by comparing simulated results to observational networks and reconciling errors in the energy balance; exploring the importance of small-scale heterogeneity to controlling water and energy fluxes; and understanding how model resolution and other scale effects complicate predicted future water export from headwater basins.

Simulating hydrology and land-energy processes at the continental scale

Changes in water storage and supply is a growing global challenge with implications in human and environmental health. Recent literature suggests that expanding hydrologic studies across continental and even global scales may provide critical insight into nonlinear interactions between the water and energy budgets; help connect, explain and guide observations from the point scale to remote sensing; inform climate and weather models that operate at the mesoscale and above; and improve national water management by bridging water management scales, e.g. from local municipalities to inter-state water policies. The Maxwell group models hydrologic processes across the Continental US (CONUS) using an integrated surface-subsurface hydrologic model, ParFlow, to study the influence of climate variations on hydrologic processes. The ParFlow CONUS model is applied to a range of applications, including 1) topographic and climatic controls to continental-scale groundwater heterogeneity; 2) the influence of hydrofacies, hydraulic parameters and availability of hydrogeologic data on simulated surface energy fluxes; 3) groundwater storage controls on Budyko relationships; 4) anthropogenic-induced anomalies to recharge and their scale-dependent impacts to national groundwater resources; 5) land-atmosphere interactions, specifically the impact of terrestrial hydrology representation in the lower boundary condition of meteorological and climate modeling; and 6) interannual variability of groundwater anomalies and comparisons of major storage changes to the Gravity Research and Climate Recovery Experiment. Studying integrated hydrologic processes across a range of scales will improve our understanding of water storage, water depletion, and groundwater-land surface coupling, and will improve national water management.

Interoperable Design of Extreme-scale Application Software

(IDEAS-Watersheds) The IDEAS-Watersh Project is intent on improving scientific productivity by qualitatively changing scientific software developer productivity, enabling a fundamentally different attitude to creating and supporting computational science and engineering (CSE) applications.

Education and Outreach

AGU-TV created a really nice video that highlights the IGWMC education and outreach program. Education and outreach is an important part of science and of the graduate experience and the IGWMC students, postdocs and staff are very engaged.

The IGWMC has a substantial outreach program and we regulary participate in STEM Fairs, teach at local schools, and host visits to the Princeton campus. If you are interested in having us deliver content please contact me.

R-Maxwell-OutReach PF Short Course

Team Maxwell participating in a local STEM fair and the 2019 ParFlow short course.

Digital Sandtank Aquifer Model

The HydroFrame Education Team along with Kitware have developed an online, virtual version of the popular sandtank aquifer model. This model is free open to use and we have included a user manual and a short how-to video to get you started. We will also include education modules over time. sandtank

Regularly Taught Classes

CEE 306 / ENV 318 Hydrology: Water and Climate (Spring)

CEE 586 /ENV 586 Physical Hydrology (Fall)

Sample of Prior Courses

GEGN 351 Geological Fluid Mechanics (Spring)

GEGN 585 Fluid Mechanics for Hydrology (Fall)

GEGN 598 Linking Climate and Hydrologic Models (Spring) part of the CCWAS IGERT

ESGN 501 Risk Assessment

GEGN 598A Hydrology of the Western United States

GEGN 598a Integrated Surface Water Hydrology Modeling

GEGN 598A Coupled processes and scaling in hydrology

Team Maxwell

MaxwellGroup Fall21
The Group of Rock Stars in Fall 21: (from left) Reed Maxwell, Jackson Swilley, Lisa Gallagher, Chen Yang, Tara Kelly, Calla Chennault, Hoang Tran, Nick Jadallah (not pictured: Elena Leonarduzzi, Danielle Tijerina, Amy Defnet, Bill Hasling, photo credit: Morgan Kelly, Mae-Yung Tang).

Postdocs and Staff, Current

  1. Lisa Gallagher, 10/15-present, Education and Outreach Coordinator (HMEI).
  2. Chen Yang, 9/20-present, Associate Research Scholar (CEE).
  3. Elena Leonarduzzi, 9/20-present, Postdoctoral Scholar (HMEI).
  4. Peyman Abbaszadeh, 1/22-present, Postdoctoral Scholar (CEE).
  5. Yueling Ma 1/22-present, Postdoctoral Scholar (HMEI).
  6. Mario Soriano, Jr. 6/22-present, Postdoctoral Scholar (HMEI), co-supervised with Allison Carruth.
  7. Amy Defnet, 11/21-present, Research Software Engineer (HMEI).
  8. William Hasling, 11/21-present, Sr. Research Software Engineer (HMEI).

PhD Students, Current

  1. Danielle Tijerina Environmental Engineering. 8/19-current. Intercomparing continental scale hydrology models and community development.
  2. Jackson Swilley Environmental Engineering. 8/21-current. Understanding the subsurface and other model formulation challenges.
  3. Nicholas Jadallah Environmental Engineering. 8/21-current. Simulating the interactions between Food, Energy and Water.
  4. Harry Stone Environmental Engineering. 8/22-current. Understanding western water issues.
  5. Cathy Wang Environmental Engineering. 8/22-current. Food, Energy and Water in comparative international systems.

PhD Alums

  1. John Williams, Hydrology, Fall 2012. Dissertation Title: Building A Better Wind Forecast: A Stochastic Forecast System Using A Fully-Coupled Hydrologic-Atmospheric Model. Dr. Williams is currently faculty at California State University, Los Angeles.
  2. Adam Atchley, Hydrology, Spring 2013. Dissertation Title: Simulating Geochemical Reactive Transport In Physically And Chemically Heterogeneous Aquifers: Implications For Co2 Risk Assessment And Uncertainty. Dr. Atchley is currently scientific staff, Los Alamos National Laboratory, Computational Hydrology Group.
  3. Steven Meyerhoff, Hydrology, Spring 2013. Dissertation Title: Understanding Heterogeneity And Data Assimilation In Karst Groundwater Surface Water Interactions: The Role Of Geophysics And Hydrologic Models In A Semi-Confined Aquifer. Dr. Meyerhoff is currently Senior Technical Staff at Itasca Denver.
  4. Erica Siirila-Woodburn, Hydrology, Spring 2013. Dissertation Title: On the interplay between scaling small-scale reactions, mixing, and aquifer heterogeneity: Human health risk implications. Dr. Woodburn is currently staff at Lawrence Berkeley, National Laboratory.
  5. Lindsay Bearup, Hydrology, Summer 2014. Dissertation Title: Changing Flow, Transport, And Geochemistry In The Mountain Pine Beetle-Killed Forests Of Rocky Mountain National Park. (Co-advise with J. McCray). Dr. Bearup is now at US Bureau of Reclamation, Water Resources Planning and Operations Support Group.
  6. Laura Condon Hydrology, Summer 2015. Dissertation Title: The Role Of Large Scale Water Management In Natural Systems: Connections, Interactions And Feedbacks. Dr. Condon is currently an Assistant Professor at University of Arizona, Hydrology and Atmospheric Sciences Dept.
  7. Jennifer Jefferson Hydrology, Spring 2016. Dissertation Title: Exploring sensitivities of latent heat parameterizations using a coupled, integrated hydrologic model. Dr. Jefferson is currently with the State of Wisconsin, Department of Natural Resources.
  8. James Gilbert Hydrology, Summer 2016. Dissertation Title: Exploring Catchment Connections with Integrated Hydrologic Models: System Interactions and Responses to Groundwater Extraction and Climate Change in the San Joaquin River Basin. Dr. Gilbert is currently staff at NOAA.
  9. J. Tim Fry Hydrology, Spring 2017. Dissertation Title: High resolution modeling for water quantity and quality, understanding the role of green infrastructure best management practices in ultra urban environments: Connections, feedbacks and interactions. Dr. Fry is currently staff with Enguity.
  10. J. Joeseph Beisman Hydrology, Spring 2018. Dissertation Title: Balancing geochemistry and hydrology mountain systems under stress: Hydrogeochemical model development and application to pyrite weathering in alpine hillslopes. (Co-Advise with Alexis Navarre-Sitchler). Dr. Beisman is currently staff at Oak Ridge National Laboratory.
  11. Lauren Foster Hydrology, Summer 2018. Dissertation Title: Modeling Climate Change Impacts To Rocky Mountain Headwater Hydrology. Dr. Foster is currently staff at Neptune.
  12. Katherine Markovich Hydrologic Sciences, (UC Davis), Summer 2018. Dissertation Title: Integrating quantitative tools for improving conceptual models of alpine hydrogeology. (co-advise with G. Fogg). Dr. Markovich is currently at the USGS.
  13. Bryant Reyes Environmental Engineering. Summer 2019. Dissertation Title: Anthropogenic impacts on the water and energy balance of an urban semi-arid environment. (co-advise with Terri Hogue). Dr. Reyes is currently staff at RMS.
  14. Mary Michael Forrester Hydrology, Spring 2020. Dissertation Title: Understanding Water Fluxes Through Land, Vegetation and Air with Coupled Atmospheric and Hydrologic Modeling at Extreme Scales. Dr. Forrester is now a PostDoc at NASA.
  15. Anna Ryken Hydrology, Spring 2021. Dissertation Title: Constraining evapotranspiration and understanding ET drivers and limitations in a mountain headwaters system. Dr. Ryken is now staff at LRE Water.
  16. Lauren Thatch Hydrology, Fall 2021. Dissertation Title: Water management modeling within integrated hydrologic models: Process development and insights on water use impacts throughout the hydrologic cycle. Dr. Thatch is now at US Bureau of Reclamation, Water Resources Planning and Operations Support Group.

MS Thesis Alums

  1. Steven Meyerhoff, Hydrology, Spring 2010. Thesis Title: An integrated surface-subsurface model to approximate runoff for heterogeneous slopes.
  2. Erica Siirila, Hydrology, Fall 2010. Thesis Title: A quantitative methodology to assess the risks to human health from CO2 leakage into groundwater.
  3. Laura Condon Hydrology Spring 2012. Thesis Title: The impact of subsurface conceptualization on land energy fluxes and regional water budgets.
  4. Sophia Wolfenden Hydrology Fall 2012. Thesis Title: Watering the central valley: Modeling water flow and the affects of irrigation in the san joaquin valley, california using parflow.
  5. Kimberly Bandy-Baldwin Hydrology,Spring 2012. Thesis Title: Investigation of groundwater-surface water interactions at selected sites along the rio grande using high frequency pressure observations.
  6. Michael Sweetenham Hydrology, Spring 2013. Thesis Title: Assessing the timing and magnitude of precipitation-induced seepage into tunnels bored through fractured rock.
  7. J. Joeseph Beisman Hydrology, Spring 2014. Thesis Title: High-Resolution Reactive Transport: A Parallel Hydrogeochemical Model.
  8. Colin Penn Hydrology, Spring 2014. Thesis Title: Green to Grey: Modeling Hydrological Responses to Mountain Pine Beetle Tree Mortality in Heterogeneous Terrain.
  9. Christine Pribulick Hydrology, Spring 2015. Thesis Title: A High Resolution, Integrated Approach to Modeling Climate and Vegetation Change Impacts to a Mountain Headwaters Catchment using ParFlow.
  10. Nicole Bogenschuetz Hydrology, Spring 2016. Thesis Title: The Effect of the Mountain Pine Beetle on Slope Stability, Soil Moisture, and Root Strength.
  11. Mary Michael Forrester Hydrology, Summer 2016. Thesis Title: Ecohydrologic Response and Atmospheric Feedbacks from Beetle-induced Transpiration Losses in Colorado Headwaters.
  12. Caitlin Collins Hydrology, Spring 2018. Thesis Title: Using an Integrated Hydrology Model to Elucidate Plant Water Use in a Headwaters Research Catchment.
  13. Annette Hein Hydrology, Spring 2018. Thesis Title: Drought on the North American High Plains: Modeling Effects of Vegetation, Temperature and Rainfall Perturbations on Regional Hydrology.
  14. Anna Ryken Hydrology, Spring 2018. Thesis Title: Sensitivity and Model Reduction of Simulated Snow Processes: Contrasting Observational and Parameter Uncertainty to Improve Prediction.
  15. Lauren Thatch Hydrology, Spring 2018. Thesis Title: Untangling Water Management and Groundwater Extraction Signals in the California Central Valley: An Integrated Hydrologic Model and Remote Sensing Synthesis Approach.
  16. Danielle Tijerina Hydrology, 2018. Thesis title: Improving U.S. National water modeling: An intercomparison of two high-resolution, continental scale models, ParFlow-CONUS and the National Water Model v1.2 configuration WRF-Hydro.
  17. Rachel Corrigan Hydrology, Spring 2019. Thesis title: Towards a better representation of the subsurface across the continental us: Developing hydraulic conductivity datasets for integrated hydrologic models.
  18. Sarah Trutner Hydrology, Spring 2019. Thesis title: Understanding scale impacts of heterogeneity and topography on water and energy fluxes in mountain meadows using a fully-integrated hydrologic model.
  19. Jackson Swilley Hydrology, Spring 2021. Thesis title: A validation and comparison of approaches to mapping hydraulic conductivity at the continental scale using the Upper Colorado river basin as a testbed.

Staff Alums

  1. Sophia Seo, (Mines) 6/11-6/14, Research Associate. Assistant Director IGWMC, Education and Outreach Liaison.
  2. Michael Morse, (Mines) 8/14-5/18, Research Associate. Assistant Director IGWMC, Education and Outreach Coordinator.
  3. Laura Condon, (Mines) 9/15-12/15, Research Associate.
  4. Tara Kelley, 3/21-8/22, IGWMC Project Manager and Administrator (HMEI).
  5. Calla Chennault, 10/20-9/22, Research Sofware Engineer (CEE).

Postdoctoral Researchers Alums

  1. Stefan J. Kollet, (LLNL) 1/04-6/05. Dr. Kollet is currently a Professor at the University of Bonn, Germany and a staff scientist and center director in the National Laboratory (F-Z) Juelich, Germany.
  2. Shadi Moqbel, (Mines) 3/09-4/10. Dr. Moqbel is currently an Associate Professor at the University of Jordan.
  3. Ian M. Ferguson, (Mines) 8/09-4/11. Dr. Ferguson is currently staff in Water Resources Group, Technical Services Center, US Bureau of Reclamation.
  4. Brian Kirsch, (Mines) 11/11-12/13. Dr\. Kirsch is currently working as a consultant at Write Water Engineers.
  5. Sonya Lopez, (Mines) 6/12-9/14. Dr. Lopez is currently an Associate Professor at California State University, Los Angeles.
  6. Nicholas Engdahl, (Mines) 1/13-8/14. Dr. Engdahl is currently an Associate Professor at Washington State University.
  7. Lindsay Bearup,, (Mines) 8/14-12/15. Dr. Bearup is currently staff in Water Resources Group, Technical Services Center, US Bureau of Reclamation.
  8. Inge de Graaf, (Mines) 9/15-3/17. Dr. de Graaf is currently an Assistant Professor at Wageningen University, NL.
  9. Basile Hector, (Mines) 11/16-6/17. Dr. Hector is currently staff at the IRD in Grenoble, France.
  10. Mohammad Danesh-Yazdi, (Mines) 2/17-2/18. Dr. Danesh-Yazdi is currently an Assistant Professor at Sharif University, Iran.
  11. Hoang Tran, (Princeton) 3/19-1/22, Dr. Tran is currently staff at the Pacific Northwest National Laboratory.


Summary: n=160, Google Scholar H-Index of 58, greater than 13,000 citations.
(# indicates postdoc author, * indicates student author, R.M.Maxwell in bold)

Refereed Journal Articles

  1. Condon, L.E., Farley, A., Jourdain, S., O'leary, P., Avery, P., Gallagher, L., Chennault, C., and Maxwell, R.M. ParFlow Sand Tank: A tool for groundwater exploration. Journal of Open Source Education, 5:55, 179, DOI:10.21105/jose.00179, 2022
  2. Leonarduzzi#, E., Tran, H.V., Bansal, V., Hull, R., De La Fuente, L., Bearup, L.A., Melchior, P., Condon, L.E. and Maxwell, R.M. Training machine learning with physics-based simulations to predict 2D soil moisture fields in a changing climate. Frontiers in Water, DOI:10.3389/frwa.2022.927113, 2022
  3. Gallagher L.K., Farley A.J., Chennault C., Cerasoli S., Jourdain S., O'Leary P., Condon L.E. and Maxwell R.M. The ParFlow Sandtank: An interactive educational tool making invisible groundwater visible. Frontiers in Water, 4:909918, DOI:10.3389/frwa.2022.909918, 2022
  4. Carroll, R. W. H., Deems, J., Maxwell, R.M., Sprenger, M., Brown, W., Newman, A., Beutler, C., Bill, M., Hubbard, S. S., and Williams, K. H. Variability in observed stable water isotopes in snowpack across a mountainous watershed in Colorado. Hydrological Processes, 36:8, e14653, DOI:10.1002/hyp.14653, 2022.
  5. Yang#, C., Maxwell, R.M., Richard Valent, R. Accelerating the Lagrangian simulation of water ages on distributed, multi-GPU platforms: The importance of dynamic load balancing, Computers & Geosciences, 166:105189, DOI:10.1016/j.cageo.2022.105189, 2022.
  6. Tran#, H., Zhang, J., O'Neil*, M.M.F., Ryken*, A., Condon,L.E. and Maxwell, R.M. A hydrological simulation dataset of the Upper Colorado River Basin from 1983 to 2019. Scientific Data, 9:16, DOI:10.1038/s41597-022-01123-w, 2022.
  7. Ryken*, A., Gochis, D.G., and Maxwell, R.M. Unraveling groundwater contributions to evapotranspiration and constraining water fluxes in a high-elevation catchment. Hydrological Process, 36:1, e14449. DOI:10.1002/hyp.14449 also Authoria preprint DOI:10.22541/au.160974909.94645181/v1, 2022.
  8. Maxwell, R.M., Condon, L.E., Mechior, P. A Physics-Informed, Machine Learning Emulator of a 2D Surface Water Model: What Temporal Networks and Simulation-Based Inference Can Help Us Learn about Hydrologic Processes, Water, 13:3633, doi:10.3390/w13243633, 2021.
  9. Cooley D., Maxwell R.M. and Smith S.M., Center Pivot Irrigation Systems and Where to Find Them: A Deep Learning Approach to Provide Inputs to Hydrologic and Economic Models. Frontiers in Water, 3:786016, doi:10.3389/frwa.2021.786016, 2021.
  10. Gleeson, T., Wagener, T., Doell, P., Zipper, S. C., West, C., Wada, Y., Taylor, R., Scanlon, B., Rosolem, R., Rahman, S., Oshinlaja, N., Maxwell, R., Lo, M.-H., Kim, H., Hill, M., Hartmann, A., Fogg, G., Famiglietti, J. S., Ducharne, A., de Graaf, I., Cuthbert, M., Condon, L., Bresciani, E., and Bierkens, M. F. P.: GMD perspective: The quest to improve the evaluation of groundwater representation in continental- to global-scale models, Geoscientific Model Development, 14:7545-7571, doi:10.5194/gmd-14-7545-2021, 2021.
  11. Condon, L. E., Kollet, S., Bierkens, M. F. P., Fogg, G. E., Maxwell, R. M., Hill, M. C., Fransen, H.-J. H., Verhoef, A., Van Loon, A. F., Sulis, M., and Abesser, C. Global groundwater modeling and monitoring: Opportunities and challenges. Water Resources Research, 57: e2020WR029500, doi:10.1029/2020WR029500, 2021
  12. Tran#, H., Leonarduzzi#, E., De la Fuente, L., Hull, R.B., Bansal, V., Chennault, C., Gentine, P., Melchior, P., Condon, L.E., and Maxwell, R.M. Development of a Deep Learning Emulator for a Distributed Groundwater-Surface Water Model: ParFlow-ML. Water,13(23), 3393, doi:10.3390/w13233393, 2021.
  13. Gallagher L.K., Williams J.M., Lazzeri D., Chennault C., Jourdain S., O'Leary P., Condon L.E., and Maxwell R.M. Sandtank-ML: An Educational Tool at the Interface of Hydrology and Machine Learning. Water, 13(23):3328, doi:10.3390/w13233328, 2021
  14. O'Niell*, M.M.F., Tijerina*, D., Condon, L., and Maxwell, R.M. Assessment of the ParFlow-CLM CONUS 1.0 integrated hydrologic model: evaluation of hyper-resolution water balance components across the contiguous United States. Geoscientific Model Development, 14, 7223-7254, doi:10.5194/gmd-14-7223-2021, 2021.
  15. Tijerina*, D., Condon, L., FitzGerald, K., Dugger, A., O'Neill, M. M., Sampson, K., Gochis, D.J., and Maxwell, R.M. Continental hydrologic intercomparison project, phase 1: A large-scale hydrologic model comparison over the continental United States. Water Resources Research, 57, e2020WR028931, doi:10.1029/2020WR028931, 2021.
  16. Yang#, C., Zhang, Y.-C., Liang, X., Olschanowsky, C., Yang, Y., and Maxwell, R.M., Accelerating the Lagrangian particle tracking of residence time distributions and source water mixing towards large scales, Computers & Geosciences, 151:104760, doi:10.1016/j.cageo.2021.104760, 2021.
  17. Zhang, J., Condon, L. E., Tran, H., and Maxwell, R. M.: A national topographic dataset for hydrological modeling over the contiguous United States, Earth System Science Data, 13:3263-3279, doi:10.5194/essd-13-3263-2021, 2021.
  18. Maavara T., Siirila-Woodburn E.R., Maina F., Maxwell R.M., Sample J.E., Chadwick K.D., et al. Modeling geogenic and atmospheric nitrogen through the East River Watershed, Colorado Rocky Mountains. PLoS ONE 16(3): e0247907, doi:10.1371/journal.pone.0247907, 2021.
  19. Leonarduzzi#, E.,Maxwell, R.M., Mirus, B. and Molnar, P. Numerical analysis of the effect of subgrid variability in a physically-based hydrological model on runoff, soil moisture, and slope stability. Water Resources Research, 57, e2020WR027326, doi:10.1029/2020WR027326, 2021.
  20. Foster*, L.M., Williams, K.H., and Maxwell, R.M. Resolution matters when modeling climate change in headwaters of the Colorado River. Environmental Research Letters, 51:10, doi:10.1088/1748-9326/aba77f, 2020.
  21. Yang#, C., Li, H.-L., Fang, Y., Cui, C., Wang, T., Zheng, C., Leung, Z.-R., Maxwell, R.M., Zhang, Y.-K., and Yang, X. Effects of groundwater pumping on ground surface temperature: A regional modeling study in the North China Plain. Journal of Geophysical Research - Atmospheres, 125:e2019JD031764, doi:10.1029/2019JD031764, 2020.
  22. Maples*, S., Foglia, L., Fogg, G.E. and Maxwell, R.M. Sensitivity of Hydrologic and Geologic Parameters on Recharge Processes in a Highly-Heterogeneous, Semi-Confined Aquifer System. Hydrogeology and Earth Systems Sciences, 24:2437-2456, doi:10.5194/hess-24-2437-2020, 2020.
  23. Kuffour, B.N.O., Engdahl, N.B., Woodward, C.S., Condon, L.E., Kollet, S.J. and and Maxwell, R.M. Simulating coupled surface-subsurface flows with ParFlow v3.5.0: capabilities, applications, and ongoing development of an open-source, massively parallel, integrated hydrologic model. Geoscientific Model Development, 13:1373-1397, doi:10.5194/gmd-13-1373-2020, 2020.
  24. Tonkin, M., Hill, M., Maxwell, R.M., and Zhen, C. Groundwater Modeling and Beyond: MODFLOW-and-More-2019 Special Issue. Groundwater, 58:325-326, doi:10.1111/gwat.12999, 2020.
  25. Tran#, H., Zhang, J., Cohard, J.-M., Condon, L.E., and Maxwell, R.M. Simulating groundwater-streamflow connections in the Upper Colorado River Basin. Groundwater, 58:392-405, doi:10.1111/gwat.13000, 2020.
  26. de Graaf#, I.E.M., Condon, L.E., and Maxwell, R.M. Hyper-resolution continental-scale 3D-aquifer parameterization for groundwater modelling. Water Resources Research, 56, e2019WR026004, doi:10.1029/2019WR026004, 2020.
  27. Thatch*, L.M., Gilbert, J.M. and Maxwell, R.M. Integrated hydrologic modeling to untangle the impacts of water management during drought. Groundwater, 58:377-391, doi:10.1111/gwat.12995, 2020.
  28. Forrester*, M.M. and Maxwell, R.M. Impact of lateral groundwater flow and subsurface lower boundary conditions on atmospheric boundary layer development over complex terrain. Journal of Hydrometeorology, 21(6):1133-1160, doi:10.1175/JHM-D-19-0029.1, 2020.
  29. Reyes*, B., Hogue, T.S. and Maxwell, R.M. Urban irrigation in the modeling of a semi-arid urban environment: Ballona Creek watershed, Los Angeles, California. Hydrological Sciences Journal, doi:10.1080/02626667.2020.1751846, 2020.
  30. Condon, L.E., Atchley A.L., and Maxwell, R.M. Evapotranspiration depletes groundwater under warming over the contiguous United States. Nature Communications, 11:873, doi:10.1038/s41467-020-14688-0, 2020.
  31. Maxwell, R.M. Water colour and climate. Nature Climate Change, 10:102-103, doi:10.1038/s41558-019-0683-6, 2020.
  32. Wilusz, D. C., Harman, C. J., Ball, W. B., Maxwell, R.M. and Buda, A. R. Using particle tracking to understand flow paths, age distributions, and the paradoxical origins of the inverse storage effect in an experimental catchment. Water Resources Research, 56, e2019WR025140, doi:10.1029/2019WR025140, 2020.
  33. Ryken*, A., Bearup, L.A., Jefferson, J., Constantine, P. and Maxwell, R.M. Sensitivity and model reduction of simulated snow processes: contrasting observational and parameter uncertainty to improve prediction. Advances in Water Resources, 135:103473, doi:10.1016/j.advwatres.2019.103473, 2020.
  34. Cottrell, S., Mattor, K.M., Morris, J.L., Fettig, C.J., McGrady, P., Maguire, D., James, P.M.A., Clear, J., Wurtzebach, Z., Wei, Y., Brunelle, A., Western, J., Maxwell, R.M., Rotar, M., Gallagher, L., and Roberts, R. Adaptive capacity in social-ecological systems: a framework for addressing bark beetle disturbances in natural resource management. Sustainability Science, 1-13, doi:10.1007/s11625-019-00736-2, 2019.
  35. Condon, L.E. and Maxwell, R.M. Simulating the sensitivity of evapotranspiration and streamflow to large-scale groundwater depletion. Science Advances, 5(6) eaav4574, doi:10.1126/sciadv.aav4574, 2019.
  36. Markovich*, K.H., Dahlke, H.E., Arumi, J.L., Maxwell, R.M. and Fogg, G.E. Bayesian hydrograph separation in a minimally gauged alpine volcanic watershed in central Chile. Journal of Hydrology, 575:1288-1300, doi:10.1016/j.jhydrol.2019.06.014, 2019.
  37. Hein*, A., Condon, L.E. and Maxwell, R.M. Evaluating the relative importance of precipitation, temperature and land-cover change in the hydrologic response to extreme meteorological drought conditions over the North American High Plains. Hydrology and Earth System Sciences, 23:1931-1950, doi:10.5194/hess-23-1931-2019, 2019.
  38. Maples*, S., Fogg, G.E. and Maxwell, R.M. Modeling managed aquifer recharge processes in a highly heterogeneous, semi-confined aquifer system. Hydrogeology Journal, 1-20, doi:10.1007/s10040-019-02033-9, 2019.
  39. Condon, L.E. and Maxwell, R.M. Modified priority flood and global slope enforcement algorithm for topographic processing in physically based hydrologic modeling applications. Computers and Geosciences, 126:73-83, doi:10.1016/j.cageo.2019.01.020, 2019.
  40. Foster*, L.M. and Maxwell, R.M., Sensitivity analyses of hydraulic conductivity and Manning's n parameters lead to new method to scale effective hydraulic conductivity across model resolutions. Hydrological Processes, 33(3):332-349, doi:10.1002/hyp.13327, 2019.
  41. Maxwell, R.M., Condon, L.E., Danesh-Yazdi#, M. and Bearup, L.A. Exploring source water mixing and transient residence time distributions of outflow and evapotranspiration with an integrated hydrologic model and Lagrangian particle tracking approach. Ecohydrology, 12(1):e2042, doi:10.1002/eco.2042, 2019.
  42. Fry*, T. and Maxwell, R.M. Using a distributed hydrologic model to improve the green infrastructure parameterization used in a lumped model. Water, 10(12), doi:10.3390/w10121756, 2018.
  43. Reyes*, B., Hogue, T.S. and Maxwell, R.M. Urban irrigation suppresses land surface temperature and changes the hydrologic regime in semi-arid regions. Water, 10(11), doi:10.3390/w10111563, 2018.
  44. Gou, S., Miller, G. R., Saville, C., Maxwell, R.M., and Ferguson, I.M. Simulating groundwater uptake and hydraulic redistribution by phreatophytes in a high-resolution, coupled subsurface-land surface model. Advances in Water Resources, 121:245-262, doi:10.1016/j.advwatres.2018.08.008, 2018.
  45. Forrester*, M.M., Maxwell, R.M., Bearup, L.A., and Gochis, D.J. Forest Disturbance Feedbacks from Bedrock to Atmosphere Using Coupled Hydro-Meteorological Simulations Over the Rocky Mountain Headwaters. Journal of Geophysical Research-Atmospheres, 123:9026-9046, doi:10.1029/2018JD028380, 2018.
  46. Hubbard, S.S., Williams, K.H., Agarwal, D., Banfield, J., Beller, H., Bouskill, N., Brodie, E., Carroll, R., Dafflon, B., Dwivedi, D., Falco, N., Faybishenko, B., Maxwell, R.M., Peter Nico, P., Steefel, C., Steltzer, H., Tokunaga, T., Tran, P.A., Wainwright, H. and Varadharajan C. The East River, CO Watershed: A Mountainous Community Testbed for Improving Predictive Understanding of Multi-Scale Hydrological-Biogeochemical Dynamics. Vadose Zone Journal, 17(1):1-25, doi:10.2136/vzj2018.03.0061, 2018.
  47. Gilbert*, J.M. and Maxwell, R.M. Contrasting warming and drought in snowmelt-dominated agricultural basins: revealing the role of elevation gradients in regional response to temperature change. Environmental Research Letters, 13:7, doi:10.1088/1748-9326/aacb38, 2018.
  48. Maxwell, R.M., Navarre-Sitchler, A.K. and Tonkin, M. Forward: Modeling for Sustainability and Adaptation. Groundwater, 56:4, 515-516, doi:10.1111/gwat.12795, 2018.
  49. Danesh-Yazdi#, M., Klaus, J., Condon, L.E., and Maxwell, R.M. Bridging the gap between numerical solutions of travel time distributions and analytical storage selection functions. Hydrological Processes, doi:10.1002/hyp.11481, 2018.
  50. McDowell, N.G., Michaletz, S. T., Bennett, K.E., Solander, K.C., Xu, C., Maxwell, R.M. and Middleton, R.S. Predicting chronic climate-driven disturbances and their mitigation. Trends in Ecology and Evolution, 33(1):15-27, doi:10.1016/j.tree.2017.10.002, 2018.
  51. Fan, Y., Leung, L.R., Duan, Z., Wigmosta, M.S., Maxwell, R.M., Chambers, J.Q. and Tomasella, J. Influence of landscape heterogeneity on water available to tropical forests in an Amazonian catchment and implications for modeling drought response. Journal of Geophysical Research - Atmospheres, 16(27):8410-8426, doi:10.1002/2017JD027066, 2017.
  52. Fry*, T.J. and Maxwell, R.M. Evaluation of distributed BMPs in an Urban Watershed: High resolution modeling for Stormwater Management. Hydrological Processes , 31(15):2700-2712, doi:10.1002/hyp.11177, 2017.
  53. Gilbert*, J.M., Maxwell, R.M. and Gochis, D.J. Effects of water table configuration on the planetary boundary layer over the San Joaquin River watershed, California. Journal of Hydrometeorology, 18:1471-1488, doi:10.1175/JHM-D-16-0134.1, 2017.
  54. Sweetenham* M.G., Maxwell, R.M. and Santi, P.M. Assessing the timing and magnitude of precipitation-induced seepage into tunnels bored through fractured rock. Tunnelling and Underground Space Technology, 65:62-75, doi:10.1016/j.tust.2017.02.003, 2017.
  55. Winnick, M., Carroll, R.W.H., Williams, K.H., Maxwell, R.M., Dong, W. and Maher, K. Snowmelt controls on concentration-discharge relationships and the balance of oxidative and acid-base weathering fluxes in an alpine catchment, East River, Colorado. Water Resources Research, 53(3) 2507-2523, doi:10.1002/2016WR019724, 2017.
  56. Sulis, M., Williams, J.L., Shrestha, P., Diederich, M., Simmer, C., Kollet, S.J., and Maxwell, R.M. Coupling groundwater, vegetation, and atmospheric processes: a comparison of two integrated models. Journal of Hydrometeorology, 18:1489-1511, doi:10.1175/JHM-D-16-0159.1, 2017.
  57. Condon, L.E. and Maxwell, R.M. Systematic shifts in Budyko relationships caused by groundwater storage changes. Hydrology and Earth System Sciences, 21, 1-19, doi:10.5194/hess-21-1-2017, 2017.
  58. Gilbert*, J.M. and Maxwell, R.M. Examining regional groundwater-surface water dynamics using an integrated hydrologic model of the San Joaquin River basin. Hydrology and Earth System Sciences, 21, 923-947, doi:10.5194/hess-21-923-2017, 2017.
  59. Jefferson*, J.L., Maxwell, R.M., Constantine, P.G. Exploring the sensitivity of photosynthesis and stomatal resistance parameters in a land surface model. Journal of Hydrometeorology, 18(3):897-915, doi:10.1175/JHM-D-16-0053.1, 2017.
  60. Kollet, S., Sulis, M., Maxwell, R.M., Paniconi, C., Putti, M., Bertoldi, G., Coon, E.T., Cordano, E., Endrizzi, S., Kikinzon, E., Mouche, E., Mügler, C., Park, Y-J, Stisen, S., Sudicky, E., The Integrated Hydrologic Model Intercomparison Project, IH-MIP2: A second set of benchmark results to diagnose integrated hydrology and feedbacks, Water Resources Research, 53(1), 867-890, doi:10.1002/2016WR019191, 2017.
  61. Pribulick*, C.E., Foster*, L.M., Bearup, L.A., Navarre-Sitchler, A.K., Williams, K.H., Carroll, R.W.H, and Maxwell, R.M. Contrasting the hydrologic response due to land cover and climate change in a mountain headwaters system. Ecohydrology, 9:8, 1431-1438, doi:10.1002/eco.1779, 2016.
  62. Maxwell, R.M. and Condon, L.E. Connections between groundwater flow and transpiration partitioning. Science, 353:6297, 377-380, doi:10.1126/science.aaf7891, 2016.
  63. Kenwell, A., Navarre-Sitchler, A., Prugue, R., Spear, J.R., Hering, A.S., Maxwell, R.M., Carroll, R.W.H., Williams, K.H. Using geochemical indicators to distinguish high biogeochemical activity in floodplain soils and sediments. Science of the Total Environment, 563-564, 386-395, doi:10.1016/j.scitotenv.2016.04.014, 2016.
  64. Kurtz, W., He, G., Kollet, S.J., Maxwell, R.M., Vereecken, H. and Hendricks Franssen,H.-J. TerrSysMP-PDAF (version 1.0): A modular high-performance data assimilation framework for an integrated land surface-subsurface model. Geoscientific Model Development , 9, 1341-1360, doi:10.5194/gmd-9-1341-2016, 2016.
  65. Gilbert*, J.M., Jefferson*, J.L., Constantine, P.G. and Maxwell, R.M. Global spatial sensitivity of runoff to subsurface permeability using the active subspace method. Advances in Water Resources, 92, 30-42, doi:10.1016/j.advwatres.2016.03.020, 2016.
  66. Penn*, C.A., Bearup#, L.A., Maxwell, R.M. and Clow, D.W. Numerical experiments to explain multi-scale hydrological responses to mountain pine beetle tree mortality in a headwater watershed. Water Resources Research, 52:4, 3143-3161, doi:10.1002/2015WR018300, 2016.
  67. Markovich*, K.H., Maxwell, R.M. and Fogg, G.E. Hydrogeological response to climate change in alpine hillslopes. Hydrological Processes, doi:10.1002/hyp.10851, 2016.
  68. Lopez#, S.R. and Maxwell, R.M. Identifying Urban Features from LiDAR for a High-Resolution Urban Hydrologic Model. Journal of the American Water Resources Association, 52:3, 756-768, doi:10.1111/1752-1688.12425, 2016.
  69. Foster*, L.M., Bearup#, L.A., Molotch, N.P., Brooks, P.D. and Maxwell, R.M. Energy Budget Increases Reduce Mean Streamflow More Than Snow-Rain Transitions: Using integrated modeling to isolate climate change impacts on Rocky Mountain hydrology. Environmental Research Letters, 11(40), doi:10.1088/1748-9326/11/4/044015, 2016.
  70. Bearup*, L.A., Maxwell, R.M. and McCray, J.E. Hillslope response to insect-induced land-cover change: an integrated model of end-member mixing. Ecohydrology, 9, 195-203, doi:10.1002/eco.1729, 2016.
  71. Maxwell, R.M., Condon*, L.E. , Kollet, S.J., Maher, K., Haggerty, R., and Forrester*, M.M. The imprint of climate and geology on the residence times of groundwater. Geophysical Research Letters, 43, doi:10.1002/2015GL066916, 2016.
  72. Ferguson#, I.M., Jefferson*, J.L., Maxwell, R.M. and Kollet, S.J. Effects of Root Water Uptake Formulation on Simulated Water and Energy Budgets at Local and Basin Scales. Environmental Earth Sciences, 75(15), doi:10.1007/s12665-015-5041-z, 2016.
  73. Reyes*, B., Maxwell, R.M. and Hogue, T.S. Impact of lateral flow and spatial scaling on the simulation of semi-arid urban land surfaces in an integrated hydrologic and land surface model. Hydrologic Processes, doi:10.1002/hyp.10683, 2015.
  74. Brooks, P.D., Chorover, J., Fan, Y., Godsey, S.E., Maxwell, R.M., McNamara, J.P., Tague, C. Hydrological Partitioning in the Critical Zone: Recent Advances and Opportunities for Developing Transferrable Understanding of Water Cycle Dynamics. Water Resources Research, 51, doi:10.1002/2015WR017039, 2015.
  75. Condon*, L.E. and Maxwell, R.M. Evaluating the relationship between topography and groundwater using outputs from a continental scale integrated hydrology model. Water Resources Research, 51, doi:10.1002/2014WR016774, 2015.
  76. Clark, M.P., Fan, Y., Lawrence, D.M., Adam, J.C., Bolster, D., Gochis, D.J., Hooper, R.P., Kumar, M., Leung, L.R., Mackay, D.S., Maxwell, R.M., Shen, C., Swensen, S.C., Zeng, X. Improving the representation of hydrologic processes in Earth System Models. Water Resources Research , 51, doi:10.1002/2015WR017096, 2015.
  77. Jefferson*, J.L., Gilbert*, J.M., Constantine, P.G. and Maxwell, R.M. Active subspaces for sensitivity analysis and dimension reduction of an integrated hydrologic model. Computers and Geosciences, 83, 127-138, doi:10.1016/j.cageo.2015.07.001, 2015.
  78. Jefferson*, J.L. and Maxwell, R.M. Evaluation of simple to complex parameterizations of bare ground evaporation. Journal of Advances in Modeling Earth Systems, 7, 1-15, doi:10.1002/2014MS000398, 2015.
  79. Rihani*, J., Chow, F.K., and Maxwell, R.M. Isolating Effects of Terrain and Soil Moisture Heterogeneity on the Atmospheric Boundary Layer: Idealized simulations to diagnose land-atmosphere feedbacks. Journal of Advances in Modeling Earth Systems, 7(2), 915-937, doi:10.1002/2014MS000371, 2015.
  80. Condon*, L.E., Hering, A.S. and Maxwell, R.M. Quantitative assessment of groundwater controls across major US river basins using a multi-model regression algorithm. Advances in Water Resources, 82, 106-123, doi:10.1016/j.advwatres.2015.04.008, 2015.
  81. Maxwell, R.M., Condon*, L.E. , and Kollet, S.J. A high resolution simulation of groundwater and surface water over most of the continental US with the integrated hydrologic model ParFlow v3. Geoscientific Model Development, 8, 923-937, doi:10.5194/gmd-8-1-2015, 2015.
  82. Beisman*, J.J., Maxwell, R.M., Navarre-Sitchler, A.K., Steefel, C.I., and Molins Rafa, S. ParCrunchFlow: An Efficient, Parallel Reactive Transport Simulation Tool for Physically and Chemically Heterogeneous Saturated Subsurface Environments. Computational Geosciences, 19(2), 403-422, doi:10.1007/s10596-015-9475-x, 2015.
  83. Seck, A. Welty, C., and Maxwell, R.M. Spin-up behavior and effects of initial conditions for an integrated hydrologic model. Water Resources Research, 51, doi:10.1002/2014WR016371, 2015.
  84. Kirsch#, B.R. and Maxwell, R.M. The Use of a Water Market to Minimize Drought-Induced Losses in the Bay Area of California. Journal- American Water Works Association, 107,5, doi:10.5942/jawwa.2015.107.0066, 2015.
  85. Bhaskar, A.S. Welty, C., Maxwell, R.M. and Miller, A.J. Untangling the effects of urban development on subsurface storage in Baltimore. Water Resources Research , 51,2, 1158-1181, doi:10.1002/2014WR016039, 2015.
  86. Engdahl#, N.B. and Maxwell, R.M. Quantifying changes in age distributions and the hydrologic balance of a high- mountain watershed from climate induced variations in recharge. Journal of Hydrology, 522, 152-162, doi:10.1016/j.jhydrol.2014.12.032, 2015.
  87. Bierkens, M.F.P., Bell, V., Burek, P., Chaney, N., Condon*, L.E., David, C., de Roo, A., Doell, P., Drost, N., Famiglietti, J., Florke, M., Gochis, D., Houser, P., Hut, R., Keune, J., Kollet, S., Maxwell, R.M., Reager, J., Samaniego, L., Sutandudjaja, E., van de Giesen, N., Winsemius, H, and Wood, E. Hyper-resolution global hydrological modelling: what's next? Hydrologic Processes, 29(2), 310-320, doi:10.1002/hyp.10391, 2015.
  88. Siirila-Woodburn*, E.R. and Maxwell, R.M. A heterogeneity model comparison of highly resolved statistically anisotropic aquifers. Advances in Water Resources, 75, 53-66, doi:10.1016/j.advwatres.2014.10.011, 2015.
  89. Srivastava, V., Graham, W.D., Muñoz-Carpena, R. and Maxwell, R.M. Insights on geologic and vegetative controls over hydrologic behavior of a large complex basin: Global Sensitivity Analysis of an Integrated Parallel Hydrologic Model. Journal of Hydrology, 519b 2238-2257, doi:10.1016/j.jhydrol.2014.10.020, 2014.
  90. Osei-Kuffuor, D., Maxwell, R.M. and Woodward, C.S. Improved Numerical Solvers for Implicit Coupling of Subsurface and Overland Flow. Advances in Water Resources, 74 185-195, doi:10.1016/j.advwatres.2014.09.006, 2014.
  91. Atchley*, A.L., Navarre-Sitchler, A.K. and Maxwell, R.M. The Effects of Physical and Geochemical Heterogeneity on Hydro-geochemical Transport and Effective Reaction Rates. Journal of Contaminant Hydrology, 165 53-46, doi:10.1016/j.jconhyd.2014.07.008, 2014.
  92. Bearup*, L.A., Mikkelson, K.M., Wiley, J.F., Navarre-Sitchler, A.K., Maxwell, R.M., Sharp, J.O. and McCray, J.E. Metal fate and partitioning in soils under bark beetle-killed trees. Science of the Total Environment, 496 348-357, doi:10.1016/j.scitotenv.2014.07.052, 2014.
  93. Cui, Z., Welty, C. and Maxwell, R.M. Modeling Nitrogen Transport and Transformation in Aquifers Using a Particle-Tracking Approach. Computers and Geosciences, 70, 1-14, doi:10.1016/j.cageo.2014.05.005, 2014.
  94. Bearup*, L.A., Maxwell, R.M., Clow, D.W., and McCray, J.E. Hydrological effects of forest transpiration loss in bark beetle-impacted watersheds. Nature Climate Change, 4, 481-486 doi:10.1038/NCLIMATE2198, 2014.
  95. Condon*, L.E. and Maxwell, R.M. Feedbacks between managed irrigation and water availability: Diagnosing temporal and spatial patterns using an integrated hydrologic model. Water Resources Research , 50(3) 2600-2616, doi:10.1002/2013WR014868, 2014.
  96. Meyerhoff*, S.B., Maxwell, R.M., Revil, A., Martin, J.B., Karaoulis, M. and Graham, W.D. Characterization of groundwater and surface water mixing in a semi-confined karst aquifer using time-lapse electrical resistivity tomography. Water Resources Research, 50(3) 2566-2585, doi:10.1002/2013WR013991, 2014.
  97. Engdahl#, N.B. and Maxwell, R.M. Approximating groundwater age distributions using simple streamtube models and multiple tracers. Advances in Water Resources, 66, 19-31, doi:10.1016/j.advwatres.2014.02.001, 2014.
  98. Condon*, L.E. and Maxwell, R.M. Groundwater-fed irrigation impacts spatially distributed temporal scaling behavior of the natural system: A spatio-temporal framework for understanding water management impacts. Environmental Research Letters, 9(3), 034009, doi:10.1088/1748-9326/9/3/034009, 2014.
  99. Maxwell, R.M., Putti, M., Meyerhoff*, S.B., Delfs, J.-O., Ferguson, I.M., Ivanov, V., Kim, J., Kolditz, O., Kollet, S.J., Kumar, M., Lopez, S., Niu, J., Paniconi, C., Park, Y.-J., Phanikumar, M.S., Shen, C., Sudicky. E.A., and Sulis, M. Surface-subsurface model intercomparison: A first set of benchmark results to diagnose integrated hydrology and feedbacks. Water Resources Research, 50(2) 1531-1549, doi:10.1002/2013WR013725, 2014.
  100. Meyerhoff*, S.B., Maxwell, R.M., Graham, W.D. and Williams, J.L. III Improved Hydrograph Prediction Through Subsurface Characterization: Conditional Stochastic Hillslope Simulations. Hydrogeolgy Journal, doi:10.1007/s10040-014-1112-6, 2014.
  101. Williams*, J.L. III, Maxwell, R.M. and Delle Monache, L. Development and verification of a new wind speed forecasting system using an Ensemble Kalman Filter data assimilation technique in a fully coupled hydrologic and atmospheric model. Journal of Advances in Modeling Earth Systems, 5(4) 785-800, doi:10.1002/jame.20051, 2013.
  102. Condon*, L.E., Maxwell, R.M. and Gangopadhyay, S. The impact of uncertainty in subsurface conceptualization on land energy fluxes. Advances in Water Resources, 60, 188-203, doi:10.1016/j.advwatres.2013.08.001, 2013.
  103. Condon*, L.E. and Maxwell, R.M. Implementation of a linear optimization water allocation algorithm into a fully integrated physical hydrology model. Advances in Water Resources, 60, 135-147, doi:10.1016/j.advwatres.2013.07.012, 2013.
  104. Mikkelson*, K.M., Bearup*, L.A., Maxwell, R.M., Stednick, J.D., McCray, J.E. Sharp, J.O. Bark beetle infestation impacts on nutrient cycling, water quality and interdependent hydrological effects. Biogeochemistry, doi:10.1007/s10533-013-9875-8, 2013.
  105. Atchley*, A.L., Maxwell, R.M. and Navarre-Sitchler, A.K. Human health risk assessment of CO2 leakage into overlying aquifers using a stochastic, geochemical reactive transport approach. Environmental Science and Technology, 47(11), 5954-5962, doi:10.1021/es400316c, 2013.
  106. Grebel, J.E., Mohanty, S.K., Torkelson, A.A., Boehm, A.B. Higgins, C.P., Maxwell, R.M., Nelson, K.L., Sedlak, D.L. Engineered Infiltration Systems for Urban Stormwater Reclamation. Environmental Engineering Science, 30(8) 437-454, doi:10.1089/ees.2012.0312, 2013.
  107. Taylor, R.G Scanlon, B., Doell,P., Rodell, M., van Beek, R., Wada, Y., Longuevergne, L., Leblanc, M., Famiglietti, J.S., Edmunds, M., Konikow, L., Green, T.R., Chen, J., Taniguchi, M., Bierkens, M.F.P., MacDonald, A., Fan, Y., Maxwell, R.M., Yechieli, Y., Gurdak, J.J., Allen, D., Shamsudduha, M., Hiscock, K., Yeh, P.J.-F., Holman, I. and Treidel, H. Groundwater and climate change. Nature Climate Change, 3, 322-329, doi:10.1038/nclimate1744, 2013.
  108. Mikkelson*, K.M. Dickenson, E.R, Maxwell, R.M., McCray, J.E., and Sharp, J.O. Adverse water quality impacts from climate-induced forest die-off. Nature Climate Change , 3, 218-222, doi:10.1038/nclimate1724, 2013.
  109. Mikkelson*, K.M., Maxwell, R.M., Ferguson#, I.M., McCray, J.E., Stednick, J.D., Sharp, J.O. Mountain pine beetle infestation impacts: Modeling water and energy budgets at the hill-slope scale. Ecohydrology , 6(1), 64-72, doi:10.1002/eco.278, 2013.
  110. Keyes, D.E., L. C. McInnes, C. Woodward, W. Gropp, E. Myra, M. Pernice, J. Bell, J. Brown, A. Clo, J. Connors, E. Constantinescu, D. Estep, K. Evans, C. Farhat, A. Hakim, G. Hammond, G. Hansen, J. Hill, T. Isaac, X. Jiao, K. Jordan, D. Kaushik, E. Kaxiras, A. Koniges, K. Lee, A. Lott, Q. Lu, J. Magerlein, R.M. Maxwell, M. McCourt, M. Mehl, R. Pawlowski, A.P. Randles, D. Reynolds, B. Rivière, U. Rüde, T. Scheibe, J. Shadid, B. Sheehan, M. Shephard, A. Siegel, B. Smith, X. Tang, C. Wilson and B. Wohlmuth Multiphysics simulations: Challenges and opportunities. International Journal of High Performance Computing Applications , 27(1):4-83, doi:10.1177/1094342012468181, 2013.
  111. Maxwell, R.M. A terrain-following grid transform and preconditioner for parallel, large-scale, integrated hydrologic modeling. Advances in Water Resources, 53:109-117, doi:10.1016/j.advwatres.2012.10.001, 2013.
  112. Navarre-Sitchler#, A.K., Maxwell, R.M., Siirila*, E.R., Hammond, G.H. and Lichtner, P.C. Elucidating geochemical response of shallow heterogeneous aquifers to CO2 leakage using high-performance computing: implications for monitoring of CO2 sequestration. Advances in Water Resources, 53:45-55, doi:10.1016/j.advwatres.2012.10.005, 2013.
  113. Atchley*, A.L., Maxwell, R.M. and Navarre-Sitchler#, A.K. Linking complex geochemical and hydrological processes using streamlines for highly-resolved, reactive transport CO2 leakage scenarios. Advances in Water Resources, 52:93-106, doi:10.1016/j.advwatres.2012.09.005, 2013.
  114. de Rooij#, R., Graham, W., Maxwell, R.M. A particle-tracking scheme for simulating pathlines in coupled surface-subsurface flows. Advances in Water Resources 53:7-18, doi:10.1016/j.advwatres.2012.07.022, 2013.
  115. Benson, D.A., Maxwell, R.M., Poeter, E., Ibrahim, H. , Dean, A., Revielle, J., Dogan, M., Major, E. Reply to comment by T. R. Ginn on “Comparison of Fickian and temporally nonlocal transport theories over many scales in an exhaustively sampled sandstone slab” Water Resources Research, 49, 2:1196, doi:10.1002/wrcr.20090, 2013.
  116. Meyerhoff*, S.B., Karaoulis, M., Fiebig, F., Maxwell, R.M., Revil, A., Martin, J.B., and Graham, W.D. Visualization of conduit-matrix conductivity differences in a karst aquifer using time-lapse electrical resistivity. Geophysical Research Letters, 39, L24401, doi:10.1029/2012GL053933, 2012.
  117. Ferguson#, I.M. and Maxwell, R.M. Human impacts on terrestrial hydrology: Climate Change versus pumping and irrigation. Environmental Research Letters, 7 044022, doi:10.1088/1748-9326/7/4/044022, 2012.
  118. Benson, D.A., Atchley*, A.L., Maxwell, R.M., Poeter, E., Ibrahim, H. , Dean, A., Revielle, J., Dogan, M., Major, E. Reply to Comment on “Comparison of Fickian and temporally non-local transport theories over many scales in an exhaustively sampled sandstone slab.” Water Resources Research, 48, W07802, 5pp, doi:10.1029/2012WR012004, 2012.
  119. Bearup*, L.A., Navarre-Sitchler#, A.K., Maxwell, R.M., McCray, J.E. Kinetic metal release from competing processes in aquifers. Environmental Science and Technology, 46(12), 6539-6547, [doi:10.1021/es203586y](], 2012.
  120. Siirila*, E.R. and Maxwell, R.M. A new perspective on human health risk assessment: Development of a time dependent methodology and the effect of varying exposure durations. Science of the Total Environment, 431, 221-232, doi:10.1016/j.scitotenv.2012.05.030, 2012.
  121. Siirila*, E.R. and Maxwell, R.M. Evaluating effective reaction rates of kinetically driven solutes in large-scale, statistically anisotropic media: human health risk implications. Water Resources Research, 48, W04527, 23pp, doi:10.1029/2011WR011516, 2012.
  122. Siirila*, E.R., Navarre-Sitchler#, A.K., Maxwell, R.M., and McCray, J.E. A quantitative methodology to assess the risks to human health from CO2 leakage into groundwater. Advances in Water Resources, 36(2), 146-164, doi:10.1016/j.advwatres.2010.11.005, 2012.
  123. Major*, E., Benson, D.A., Revielle, J., Ibrahim*, H.,Dean*, A., Maxwell, R.M., Poeter, E. and Dogan, M. Comparison of Fickian and temporally non-local transport theories over many scales in an exhaustively sampled sandstone slab. Water Resources Research , 47, W10519, 14pp, doi:10.1029/2011WR010857, 2011.
  124. Maxwell, R.M. and Anspaugh, L.R., An improved model for the prediction of resuspension. Health Physics , 101(6) 722-730, doi:10.1097/HP.0b013e31821ddb07, 2011.
  125. Meyerhoff*, S.B. and Maxwell, R.M. Quantifying the effects of subsurface heterogeneity on hillslope runoff using a stochastic approach. Hydrogeology Journal , 19:1515-1530, doi:10.1007/s10040-011-0753-y, 2011.
  126. Williams*, J.L. III and Maxwell, R.M. Propagating subsurface uncertainty to the atmosphere using fully-coupled, stochastic simulations. Journal of Hydrometerology , 12, 690-701, doi:10.1175/2011JHM1363.1, 2011.
  127. Kollat*, J.S., Reed, P.M. and Maxwell, R.M. Many-Objective Groundwater Monitoring Network Design Using Bias-Aware Ensemble Kalman Filtering and Evolutionary Optimization. Water Resources Research, 47, W02529, doi:10.1029/2010WR009194, 2011.
  128. Daniels*, M.H. Maxwell, R.M. and Chow, F.K. An algorithm for flow direction enforcement using sub-grid scale stream location data. ASCE Journal of Hydrologic Engineering , 16, 677, doi:10.1061/(ASCE)HE.1943-5584.0000340, 2011.
  129. Atchley*, A.L. and Maxwell, R.M. Influences of subsurface heterogeneity and vegetation cover on soil moisture, surface temperature, and evapotranspiration at hillslope scales. Hydrogeology Journal , 19(2), 289-305, doi:10.1007/s10040-010-0690-1, 2011.
  130. Ferguson#, I.M. and Maxwell, R.M. Hydrologic and land–energy feedbacks of agricultural water management practices. Environmental Research Letters , 6, 014006, doi: 10.1088/1748-9326/6/1/014006, 2011.
  131. Maxwell, R.M., Lundquist, J.K., Mirocha, J., Smith, S.G., Woodward, C.S. and Tompson, A.F.B. Development of a coupled groundwater-atmospheric model. Monthly Weather Review , 139(1), 96-116, doi:10.1175/2010MWR3392, 2011.
  132. Rihani*, J.F., Maxwell, R.M. and Chow, F.K. Coupling Land Surface and Groundwater Processes: Idealized Simulations to Identify Effects of Terrain and Subsurface Heterogeneity on Land Surface Energy Fluxes. Water Resources Research , 46, W12523, doi:10.1029/2010WR009111, 2010.
  133. Maxwell, R.M. Infiltration in arid environments: Spatial patterns between subsurface heterogeneity and water-energy balances. Vadose Zone Journal , 9, 970-983, doi:10.2136/vzj2010.0014, 2010.
  134. Ferguson#, I.M. and Maxwell, R.M. The role of groundwater in watershed response and land-surface feedbacks under climate change. Water Resources Research 46, W00F02, doi:10.1029/2009WR008616, 2010.
  135. Kollet, S.J., Maxwell, R.M., Woodward, C.S., Smith, S.G., Vanderborght, J., Vereecken, H., and Simmer, C. Proof-of-concept of regional scale hydrologic simulations at hydrologic resolution utilizing massively parallel computer resources, Water Resources Research, 46, W04201, doi:10.1029/2009WR008730, 2010.
  136. Sulis*, M., Meyerhoff*, S.B., Panniconi, C., Maxwell, R.M., Putti, M. and Kollet#, S.J. A comparison of two physics-based numerical models for simulating surface water–groundwater interactions, Advances in Water Resources 33(4), 456-467, doi:10.1016/j.advwatres.2010.01.010, 2010.
  137. Maxwell, R.M. Coupled surface-subsurface modeling across a range of temporal and spatial scales, Vadose Zone Journal , doi:10.2136/vzj2009.0117, 2009.
  138. Frei*, S., Fleckenstein, J.H., Kollet#, S.J. and Maxwell, R.M. Patterns and dynamics of river-aquifer exchange with variably-saturated flow using a fully-coupled model. Journal of Hydrology 375(3-4), 383-393, doi:10.1016/j.jhydrol.2009.06.038, 2009.
  139. Kollet#, S.J., Cvijanovic, I., Schuettemeyer, D., Maxwell, R.M., Moene, A.F. and Bayer P. The Influence of Rain Sensible Heat and Subsurface Energy Transport on the Energy Balance at the Land Surface. Vadose Zone Journal, doi:10.2136/vzj2009.0005, 2009.
  140. Maxwell, R.M., Tompson, A.F.B. and Kollet, S.J. A Serendipitous, Long-Term Infiltration Experiment: Water and Tritium Circulation Beneath the CAMBRIC Trench at the Nevada Test Site. Journal of Contaminant Hydrology 108(1-2) 12-28, doi:10.1016/j.jconhyd.2009.05.002, 2009.
  141. de Barros*, F.P.J., Rubin, Y. and Maxwell, R.M. The concept of comparative information yield curves and their application to risk-based site characterization. Water Resources Research 45, W06401, doi:10.1029/2008WR007324, 2009.
  142. Lobell, D., Bala, G. Mirin, A., Phillips, T., Maxwell, R.M. and Rotman, D. Regional differences in the influence of irrigation on climate. Journal of Climate 22(8) 2248-2255, doi:10.1175/2008JCLI2703.1, 2009.
  143. Maxwell, R.M. and Kollet, S.J. Interdependence of groundwater dynamics and land-energy feedbacks under climate change. Nature Geoscience 1(10) 665-669, doi:10.1038/ngeo315, 2008.
  144. Kollet#, S.J. and Maxwell, R.M. Demonstrating fractal scaling of baseflow residence time distributions using a fully-coupled groundwater and land surface model. Geophysical Research Letters 35, L07402, doi:10.1029/2008GL033215, 2008.
  145. Maxwell, R.M. and Kollet, S.J., Quantifying the effects of three-dimensional subsurface heterogeneity on Hortonian runoff processes using a coupled numerical, stochastic approach. Advances in Water Resources, 31(5), 807-817, doi:10.1016/j.advwatres.2008.01.020, 2008.
  146. Kollet#, S.J. and Maxwell, R.M., Capturing the influence of groundwater dynamics on land surface processes using an integrated, distributed watershed model, Water Resources Research, 44:W02402, doi:10.1029/2007WR006004, 2008.
  147. Maxwell, R.M., Carle, S.F. and Tompson, A.F.B., Contamination, Risk, and Heterogeneity: On the Effectiveness of Aquifer Remediation, Environmental Geology, 54:1771-1786, doi:10.1007/s00254-007-0955-8, 2008.
  148. Maxwell, R.M., Chow, F.K. and Kollet#, S.J., The groundwater-land-surface-atmosphere connection: soil moisture effects on the atmospheric boundary layer in fully-coupled simulations, Advances in Water Resources, 30(12), doi:10.1016/j.advwatres.2007.05.018, 2447-2466, 2007.
  149. Maxwell, R.M., Welty, C. and R.W. Harvey, R.W., Revisiting the Cape Cod Bacteria Injection Experiment Using a Stochastic Modeling Approach, Environmental Science and Technology 41(15), doi:10.1021/es062693a, 5548-5558, 2007.
  150. Kollet#, S.J. and R.M. Maxwell. Integrated surface-groundwater flow modeling: A free-surface overland flow boundary condition in a parallel groundwater flow model. Advances in Water Resources , 29(7), 945-958, doi:10.1016/j.advwatres.2005.08.006, 2006.
  151. Maxwell, R.M. and N.L. Miller. Development of a coupled land surface and groundwater model. Journal of Hydrometeorology, 6(3), 233-247, doi:10.1175/JHM422.1, 2005.
  152. Maxwell, R.M., C. Welty, and A.F.B. Tompson. Streamline-based simulation of virus transport resulting from long term artificial recharge in a heterogeneous aquifer, Advances in Water Resources , 25(10),1075-1096, doi:10.1016/S0309-1708(03)00074-5, 2003.
  153. Tompson AFB., C.J. Bruton, G.A. Pawloski, D.K. Smith, W.L. Bourcier , D.E. Shumaker A.B. Kersting, S.F. Carle and R.M. Maxwell. On the evaluation of groundwater contamination from underground nuclear tests. Environmental Geology . 42(2-3):235-247, doi:10.1007/s00254-001-0493-8, 2002.
  154. Anspaugh, L.R., K.I. Gordeev, I.A. Likhtarev, R.M. Maxwell, S.L. Simon, Movement of Radionuclides in Terrestrial Ecosystems by Physical Processes, Health Physics , 82(5), 669-679, doi:10.1097/00004032-200205000-00013, 2002.
  155. Tompson, A.F.B., S.F. Carle, N.D. Rosenberg, and R.M. Maxwell, Analysis of groundwater migration from artificial recharge in a large urban aquifer: A simulation perspective Water Resources Research , 35(10),2981-2998, doi:10.1029/1999WR900175, 1999.
  156. Maxwell, R.M., W.E. Kastenberg, and Y. Rubin, A methodology to integrate site characterization information into groundwater-driven health risk assessment. Water Resources Research , 35(9), 2841-2856, doi:10.1029/1999WR900103, 1999.
  157. Rubin, Y., A. Sun*, R.M. Maxwell, and A. Bellin, The concept of block effective macrodispersivity and a unified approach for grid-scale and plume-scale dependent transport. Journal of Fluid Mechanics , 395, 161-180, doi:10.1017/S0022112099005868, 1999.
  158. Maxwell, R.M. and W.E. Kastenberg, A Model for Assessing and Managing the Risks of Environmental Lead Emissions. Stochastic Environmental Research and Risk Assessment, 13(4), 231-250, doi:10.1007/s004770050041, 1999.
  159. Maxwell, R.M.,and W.E. Kastenberg, Stochastic Environmental Risk Analysis: An Integrated Methodology for Predicting Cancer Risk from Contaminated Groundwater. Stochastic Environmental Research and Risk Assessment, 13(1-2), 27-47, doi:10.1007/s004770050030, 1999.
  160. Maxwell, R.M., S.D Pelmulder, A.F.B. Tompson, and W.E. Kastenberg, On the Development of a New Methodology for Groundwater-Driven Health Risk Assessment. Water Resources Research, 34(4), 833-847, doi:10.1029/97WR03605, 1998.



ParFlow is an open-source, object-oriented, parallel watershed flow model. It includes fully-integrated overland flow, the ability to simulate complex topography, geology and heterogeneity and coupled land-surface processes including the land-energy budget, biogeochemistry and snow (via CLM). It is multi-platform and runs with a common I/O structure from laptop to supercomputer. ParFlow is the result of a long, multi-institutional development history and is now a collaborative effort between Princeton, F-Z Juellich, UniBonn, LLNL, WSU, LBL, and LTHE. ParFlow has been coupled to the mesoscale, meteorological code ARPS, the NCAR code WRF and the German Weather Service model COSMO.

ParFlow Web Page

ParFlow Blog

ParFlow is on GitHub, we recommend starting there. The project may be accessed here.


EcoSLIM is a Lagrangian, particle-tracking model for simulating subsurface , diagnosing transport, ravel times, paths etc, and integrates seamlessly with ParFlow.

For more information please contact me by email.