Research

We are interested in how complexity and heterogeneity in physical structure (topography, substrate composition, large woody debris, floodplain forest patterns) affect water distribution, flows, and pollutant transport among channel, floodplain, hyporheic, and groundwater environments in stream, river, wetland, and aquifer systems.  Further, we are interested in how such hydrologic patterns interact with human stressors such as climate change, land use change (e.g., urbanization), and engineered hydraulic structures to impact pollutant migration, water quality, and various metrics of human and aquatic ecological health.  In general, our approach to research is to accelerate the development of conceptual understanding by encouraging synergistic feedback between quantitative modeling and flume or field measurements.  We seek out relationships between driving factors and system response, noting nonlinearities and how they can be used to optimize engineering design and sustainable landscape management.

Recent Research Projects

1. Restoration of surface water-groundwater and floodplain exchange in streams, rivers, and wetlands

     
   This project is evaluating the potential value of restoring hyporheic exchange and floodplain exchange (creation of riverine wetlands) as a part of stream restoration projects.  Key benefits may include toxics attenuation, nutrient processing, and thermal mitigation, benefitting both ecological and human health in river systems.
   
   Collaborators: Durelle Scott, Cully Hession, Mike Gooseff
   
   Students: Elizabeth Cranmer, David Azinheira, Christopher Guth, Masud Rana, Benjamin Hammond, Kristen Brooks, Michael Calfe, Carly Federman, Morgan Oehler
   
   Support: National Science Foundation (ENG-CBET-Environmental Sustainability), Award#1066817; Core Fulbright Scholar Award to Taiwan, "Effect of Floodplain Inundation on River Pollution in Taiwan’s Strong Monsoonal Climate;" Chesapeake Bay Trust, Award #18006.
   
   We have also gotten support from several NSF REU programs.  One produced an excellent website with flood experiment results.
   
   Publications:
   

   Federman, C.E., D.T. Scott, and E.T. Hester. 2023. Impact of floodplain and Stage 0 stream restoration on flood attenuation and floodplain exchange during small frequent storms. Journal of the American Water Resources Association 59:29–48.  Link to open access article.
   
   Calfe, M.L., D.T. Scott, Hester, E.T. 2022. Nitrate removal by watershed-scale hyporheic stream restoration: Modeling approach to estimate effects and patterns at the stream network scale. Ecological Engineering, 175: 106498.
   
   Hester, E.T., A.Y.-C. Lin, and C.W. Tsai.  2020.  Effect of floodplain restoration on photolytic removal of pharmaceuticals.  Environmental Science & Technology 54, 3278−3287.
   
   Hester, E.T., K.E. Brooks and D.T. Scott.  2018.  Comparing reach scale hyporheic exchange and denitrification induced by instream restoration structures and natural streambed morphology.  Ecological Engineering 115:105-121.
   
   Keys, T.A., H. Govenor, C.N. Jones, W.C. Hession, E.T. Hester, and D.T. Scott.  2018.  Effects of large wood on floodplain connectivity in a headwater Mid-Atlantic stream.  Ecological Engineering 118:134-142.
   
   Rana, SM.M., D.T. Scott, and E.T. Hester.  2017.  Effects of in-stream structures and channel flow rate variation on transient storage. Journal of Hydrology 548:157-169.

   Hester, E.T., B. Hammond, and D.T. Scott.  2016.  Effects of inset floodplains and hyporheic exchange induced by in-stream structures on nitrate removal in a headwater stream.  Ecological Engineering 97:452-464.
   
   Hester, E.T., C.R. Guth, D.T. Scott, and C.N. Jones.  2016.  Vertical surface water-groundwater exchange processes within a short residence time floodplain induced by experimental floods along a headwater stream.  Hydrological Processes 30(21):3770–3787.
   
   Jones, C.N., D.T. Scott, C.R. Guth, E.T. Hester, and W.C. Hession.  2015.  Seasonal variation in floodplain biogeochemical processing in a restored headwater stream.  Environmental Science & Technology 49(22):13190−13198.
   
   Azinheira, D.L., D.T. Scott, W.C. Hession, and E.T. Hester.  2014.  Comparison of effects of inset floodplains and hyporheic exchange induced by in-stream structures on solute retention.  Water Resources Research 50(7):6168-6190.
   
   Hester, E.T., and E.N. Cranmer.  2014.  Variation of hyporheic exchange potential among urban region streams: implications for stream restoration.  Environmental & Engineering Geoscience 20(3):287-304.
   
   Hester, E.T. and M.N. Gooseff.  2011.  Hyporheic restoration in streams and rivers.  Chapter in Stream Restoration in Dynamic Fluvial Systems: Scientific Approaches, Analyses, and Tools (Simon, A., S.J. Bennett, and J.M. Castro, Eds.).
   
   Hester, E.T., and M.N. Gooseff.  2010.  Moving Beyond the Banks: Hyporheic Restoration Is Fundamental to Restoring Ecological Services and Functions of Streams.  Environmental Science & Technology  44(5):1521-1525.  Link to cover article and feature.
   
   
   

2. Measuring environmental sustainability of water resources management in watersheds

                   

   This project is working to develop comprehensive yet feasible metrics for quantify environmental sustainability of water resources management within watersheds.
   
   Collaborators: John Little, Cayelan Carey
   
   Publications:
   

   Amaya, M., F. Duchin, E.T. Hester, and J.C. Little. 2022. Applying a coupled hydrologic-economic modeling framework: Evaluating conjunctive use strategies for alleviating seasonal watershed impacts caused by agricultural intensification. Frontiers in Water 4:913501.

   Amaya, M., F. Duchin, E.T. Hester, and Little, J.C. 2022. Applying a coupled hydrologic-economic modeling framework: Evaluating alternative options for reducing impacts for downstream locations in response to upstream development. Sustainability, 14:6630.

   Little, J.C., E.T. Hester, S. Elsawah, G.M. Filz, A. Sandu, C.C. Carey, T. Iwanaga, and A.J. Jakeman.  2019.  A tiered, system-of-systems modeling framework for resolving complex socio-environmental policy issues.  Environmental Modelling and Software 112:82-94.
   
   Little, J. C., E.T. Hester, and C.C. Carey.  2016.  Assessing and enhancing environmental sustainability - A conceptual review.  Environmental Science & Technology 50(13):6830-6845.
   
   Hester, E.T., and J.C. Little.  2013. Measuring environmental sustainability of water in watersheds.  Environmental Science & Technology  47(15):8083-8090.  Link to feature. 
   
   
   

3. Appalachian surface coal mine hydrology and effects on downstream waterways

   

   This project is utilizing various hydrologic tools to map hydrologic flowpaths through Appalachian lands impacted by surface coal mining.  This will provide information useful for addressing water quality issues in downstream waterways.

   Collaborators: Carl Zipper, Tom Burbey

   Students: Breeyn Greer, Katie Little

   Support: Wells Fargo, Office of Surface Mining (Department of Interior)

   Publications:
   
   Hester, E.T., K.L. Little, J.D. Buckwalter, C.E. Zipper, and T.J. Burbey.  2019.  Variability of subsurface structure and infiltration hydrology among surface coal mine valley fills.  Science of the Total Environment 651:2648–2661.
   
   Greer, B.M., T.J. Burbey, C.E. Zipper, and E.T. Hester.  2017.  Electrical resistivity imaging of preferential flow through surface coal mine valley fills with comparison to other landforms.  Hydrological Processes 31(12):2244-2260.
   
   Clark, E.V., B.M. Greer, C.E. Zipper, and E.T. Hester.  2016.  Specific conductance-stage relationships in Appalachian valley fill streams.  Environmental Earth Sciences 75:1222.
   
   Evans, D., C.E. Zipper, E.T. Hester, and S. Schoenholtz.  2015.  Hydrologic effects of surface coal mining in Appalachia (USA).  Journal of the American Water Resources Association  51(5):1436-1452.
   
   

   
   

4. Natural attenuation of pollutants at the surface water-groundwater interface in rivers

   
   This project is utilizing numerical modeling and laboratory experiments to evaluate controls on mixing and pollutant attenuation of contaminants in the hyporheic zone beneath riverbed dunes.  Applied benefits may include accounting for these affects in monitored natural attenuation, or active promotion of beneficial reactions through sustainable practices such as carbon augmentation through riparian planting.
   
   Collaborators: Mark Widdowson, Bayani Cardenas, Roy Haggerty, Sourabh Apte
   
   Students: Katie Young, Abenezer Nida, Katherine Santizo, Lauren Eastes, Seth Lotts
   
   Support: National Science Foundation (ENG-CBET-Environmental Engineering), Award#1437021; U.S. Department of Energy, Subsurface Biogeochemical Research (SBR), Award DE-SC0021402.

   Publications:

   Santizo, K.Y., M.W. Widdowson, and E.T. Hester. 2022. Numerical modeling of an abiotic hyporheic mixing-dependent reaction: Chemical evolution of mixing and reactant production zones. Journal of Contaminant Hydrology, 251:104066.
   
   Hester, E.T., K.Y. Santizo, A.A. Nida, and M.A. Widdowson. 2021. Hyporheic transverse mixing zones and dispersivity: Laboratory and numerical experiments of hydraulic controls. Journal of Contaminant Hydrology, 243: 103885.
   
   Santizo, K.Y., M.A. Widdowson, and E.T. Hester.  2020.  Abiotic mixing-dependent reaction in a laboratory simulated hyporheic zone.  Water Resources Research 56, e2020WR027090.

   Hester, E.T., L.A. Eastes, and M.A. Widdowson.  2019.  Effect of surface water stage fluctuation on mixing-dependent hyporheic denitrification in riverbed dunes.  Water Resources Research 55(6):4668-4687.

   Hester, E.T., M.B. Cardenas, R. Haggerty, and S.V. Apte.  2017.  The importance and challenge of hyporheic mixing.  Water Resources Research 53(5):3565-3575.

   Hester, E.T., K.I. Young, and M.A. Widdowson.  2014.  Controls on mixing-dependent denitrification in hyporheic zones induced by riverbed dunes: a steady-state modeling study.  Water Resources Research 50(11):9048-9066.  

   Hester, E.T., K.I. Young, and M.A. Widdowson.  2013.  Mixing of surface and groundwater induced by riverbed dunes: implications for hyporheic zone definitions and pollutant reactions.  Water Resources Research  49:5221–5237.    
   
   

5. Preferential flow at the surface water-groundwater interface in streams and rivers

   
   This project is evaluating the significance of preferential flow for surface water-groundwater exchange in stream and river systems.  We are interested in the exchange of water as well as pollutants.
   
   Collaborators: Adam Ward, Durelle Scott
   
   Students: Garrett Menichino, Amiana McEwen, Seth Lotts
   
   Support: National Science Foundation (GEO-EAR-Hydrologic Sciences), Award#1446481, Jeffress Memorial Trust, Consortium of Universities for the Advancement of Hydrologic Science, Inc. (CUAHSI) Hydrogeophysics Travel Grant, Institute for Critical Technology and Applied Science (ICTAS) at Virginia Tech
   
   Publications:
   
   Lotts, W.S., and E.T. Hester. 2023. Take it to the bank: A numerical examination of the effects of soil pipes on bypass of riparian buffer nitrate removal capacity. Journal of Hydrology 616:128821.
   
   Lotts, W. S., and E.T. Hester. 2022. Pipe dreams: The effects of stream bank soil pipes on hyporheic denitrification caused by a peak flow event. Water Resources Research, 58, e2021WR030312.  Link to open access article.
   
   Hester, E.T., and G.A. Fox. 2020. Preferential flow in riparian groundwater: Gateways for watershed solute transport and implications for water quality management. Water Resources Research, 56, e2020WR028186. Link to open access article.
   
   Hester, E.T., A.M. McEwen, B. Kim, and E. Rost.  2020.  Abundance, distribution, and geometry of naturally occurring streambank soil pipes.  Freshwater Science 39(4):735–751.
   

   Lotts, W.S., and E.T. Hester.  2020.  Filling the void: the effect of streambank soil pipes on transient hyporheic exchange during a peak flow event.  Water Resources Research 56(2), e2019WR025959.  Link to open access article.

   Menichino, G.T., and E.T. Hester.  2015.  The effect of macropores on bi-directional exchange between stream channels and bank groundwater.  Journal of Hydrology  529(3):830-842.
   
   Menichino, G.T., D.T. Scott, and E.T. Hester.  2015. Abundance and dimensions of naturally occurring macropores along stream channels and the effects of artificially constructed large macropores on transient storage.  Freshwater Science 4(1):125–138.  Invited article to special issue.
   
   Menichino, G.T., A.S. Ward, and E.T. Hester.  2014.  Macropores as preferential flow paths in meander bends.  Hydrological Processes 28(3):482-495.
   
   
   

6. Microhydropower

   
   Microhydropower, or capturing the energy of water movement on a small scale, is well suited to the mountainous western portion of Virginia, and there is high potential for this form of power generation to be a productive component of green energy.  We have recently done a series of feasibility studies for microhydropower facilities for various private clients in Virginia.  Our focus has been the hydraulic feasibility, which answers the question whether or not the particular stream has enough flow and head drop on the particular property to generate enough power to meet the needs of the project.  If microhydropower becomes more widespread, there may be concerns of cumulative impacts on aquatic ecology, thus we have also done some ecological impact assessments of client projects.
   
   
   

7. Migration of urban thermal pollution in ponds and streams

   
   This project is measuring the thermal impact of heated runoff from parking lots during summer storms in receiving streams and wetlands.  This study will help understand how urbanization impacts aquatic organisms, which are often quite sensitive to thermal perturbations.  The project will also help understand how streams and wetlands work, but providing insight into how perturbations propagate through aquatic systems.
   
   Students: Kalen Bauman
   
   Publications: Hester, E.T., and K.S. Bauman.  2013.  Stream and retention pond thermal response to heated summer runoff from urban impervious surfaces.  Journal of the American Water Resources Association  49(2):328-342.
   
   
   

8. In-stream structures, non-Darcy flow, and stream temperature

   
   This project is utilizing computational fluid dynamics models (Ansys CFX) to evaluate the overarching control of hydraulic conductivity of sediments on where and when in-stream structure induced hyporheic heat exchange is significant for subsurface thermal heterogeneity and surface water temperature.  We are also studying the onset of non-Darcy flow in coarser sediments and its significance for hyporheic processes.
   
   Students: Garrett Menichino

   Publications: Menichino, G.T., and E.T. Hester.  2014.  Hydraulic and thermal effects of in-stream structure-induced hyporheic exchange across a range of hydraulic conductivities.  Water Resources Research 50(6):4643-4661.