Zachary Easton

Courses Taught Last Five Years

BSE 4304-5304G Watershed Modeling

Other Teaching and Advising

I serve as a faulty advisor to a Senior Design team (BSE 4125-4126 Comprehensive Senior Design Project).

Program Focus

My research addresses both native and managed systems, considers processes at plot- to large river basin-scales, and is relatively evenly divided among field study/monitoring, modeling, and application of results to real world problems. Current projects focus on several areas, such as:

1. How do land use and climate (change) impact water quality? Work here focuses on characterization of the relationships between land use distributions, climate, and patterns of nutrient and water flows in the landscape. 
2. How do agricultural and urban management practices affect water quality? This work integrated plot and field scale research with basin scale modeling to assess the impact of best management practices on water quantity and quality. One of the roles has been to develop and test basin scale hydrologic models designed to provide accurate estimates of both water quality and quantity. 
3. What processes control the fate and transport of nutrients and sediment? Recent work has focused on assessing influence of anaerobic conditions on denitrification in a denitrifying bioreactor designed to treat diffuse ground water nitrate. 
4. Developing data access and sharing protocols that facilitate seamless and transparent data transfer between multiple data source. We develop tools and code that provide researchers from multiple domains with the data they need to complete their research. 
5. Can we bridge basic research and modeling to management and application? For instance, results from research efforts are currently being used to drive policy decisions on nutrient management in both agricultural and urban systems.

Current Projects

• Twenty-first century development of 21st century precision agriculture for water quality protection. USDA-AFRI. This project aims to develop a dynamic real time Decision Support System (DSS) that provides information relevant to water quality protection. A unique feature of the proposed DSS is that it will predict runoff risks in real-time and forecast risks 6-hrs to 3-days into the future.  These risks are displayed on Google-map-like images on smart phones.

• NSF-WSC-Category-1: Collaborative Proposal: Coupled Multi-scale Economic, Hydrologic, and Estuarine Modeling to Assess Impacts of Climate Change on Water Quality Management. The overarching goal of this project is to develop a quantifiable, predictive framework that couples biogeochemical and hydrologic drivers of terrestrial nutrient export with climate change to evaluate the effects of ecosystem management on estuarine function and costs of water quality protection. To achieve this goal, we propose to work broadly across common regional Chesapeake Bay watershed physiographic gradients and dominant landuses (e.g., agriculture, forest and urban). The following goals will allow us to develop a this framework based on our best current knowledge, explore the impact of climate change and extreme weather events on nutrient and sediment export, and develop new modeling paradigms to improve water quality models used for management decisions.

  1. Bracket the mid-century changes in climate for the Chesapeake Bay watershed with downscaled high-resolution regional climate models.
  2.  Evaluate likely changes in landscape patterns and magnitudes of N and P cycling and erosion using downscaled climate model outputs coupled to multi-scale landscape models.
  3.  Investigate how climate change and alternative nutrient management strategies affect water quality in the Chesapeake Bay.
  4.  Assess tradeoffs between costs of Best Management Practices (BMPs) and landscape management intended to control nitrogen (N) loadings and variability of N loadings under alternative climate change scenarios

• NSF-WSC-Category-3: Collaborative Proposal:Impacts of Climate Change on the Phenology of Linked Agriculture-Water Systems. Our proposed research is based on the premise that climate induced changes in the timing of agricultural practices  that may seem insignificant when analyzed in isolation  have the potential to create disproportionately large effects on downstream watersheds and ecosystems due to their interactions with other climate induced changes. Our objective is to explore various aspects of this premise  and, in the course of so doing, to develop new approaches and  understanding of the following four research elements of the  system, and the links between them. Here, we seek improved  understanding of:

1. How a change in climate affects farmers’ decisions about land use and timing of agricultural practice (human phenology);
2. How a change in climate, agricultural practice, and land-use  affects watersheds’ intra-annual variability of water, sediment, and nutrient export (watershed phenology);
3. How changes in timing, location, and watershed inputs affect estuary physical and biological response, including the severity of  hypoxia (estuarine phenology); and
4. How policy designed to influence agricultural land use and practice to mitigate ecosystem impacts can account for these cascading human, biological, and physical effects in water systems.

• NSF-EarthCube Building Blocks: A Broker Framework for Next Generation Geoscience. We are developing  a Broker Framework of the Geosciences which addresses the need for effective and efficient multi-disciplinary collaboration through the introduction of brokering as an EarthCube building block. The need for expanded collaboration has increased as science addresses the complex challenges of understanding and predicting Earth’s environment. The issues, identified as Grand Challenges by the NSF in their GEOVision report, are: “Understanding and forecasting the behavior of a complex and evolving Earth system” and “Reducing vulnerability and sustaining life.” This same report highlights that an “integrated and interdisciplinary approach in the geosciences will lead to new paradigms for human interactions with the Earth and guide us to solution-oriented applications.” EarthCube (EC) is the NSF GEO flagship initiative identified in the GEO Vision to create a new generation of information infrastructure. EC aims to transform the conduct of research through the development of community-guided cyberinfrastructure to integrate information and data across the geosciences.
• Decreasing Nitrogen and Phosphorus in Drainage Waters Using a Comprehensive Drainage Management Approach.Controlling nutrient loss from artificially drained agricultural lands on the Atlantic Coastal Plain requires a comprehensive approach that includes field and drainage management practices to address production and water quality concerns. Previous research by the project team has demonstrated significant nitrogen (N) and phosphorus (P) reduction with conventional and novel management practices, e.g., flow control structures, gypsum curtains, biofilter reactors. This project seeks to integrate field and drainage management practices to develop, demonstrate and test a comprehensive approach to drainage management that can be readily adopted by producers on the Coastal Plain.
• Refining P Indices in the Chesapeake Bay Region to Improve Critical Source Area Identification. Despite the apparent success of the P Index concept, there remain concerns about the effectiveness of the Indexing approach for attaining water quality goals. One of the major concerns that has been raised is that the transport component of many P indices is either not well developed, or unimportant (i.e., in some P Indices the transport scales from 0 to 1 and the source from 0 to 100 or more). Our regional project seeks to refine P management via the P Index concept, specifically:

1. Evaluate P Indices by comparing their output with water quality monitoring data and fate-and-transport models.
2. Use water quality data (monitored or predicted by model) to refine P Indices, improving their prediction of P loss potential, ensuring consistency across state boundaries and within physiographic provinces, and promoting effective recommendations for P management.
3. Predict the management impact of P Indices on nutrient management practices and water quality.

Program Focus

My program focuses on developing and delivering programing to improve our understanding of the processes that control water and chemical cycles and transport with the ultimate goal of developing policies and management practices that protect water, soil, air and other natural resources. I have two primary extension focus areas: 1) Watershed modeling and management, and 2) Climate change adaptation. I work closely with fellow scientists at Virginia Tech and other Land Grant Institutions in the Mid-Atlantic region, the USDA-NRCS, local Soil and Water Conservation Districts and Extension Agents to develop and deliver pertinent information to stakeholders. Each program area has a distinct clientele as an intended audience. My watershed modeling and management program is intended to provide regulators and scientists with cutting edge information about advances in watershed modeling capabilities and provide them with the insight and understanding they can use to drive water quality management policy and regulation, as well as provide producers, conservation personnel, and extension agents with scientifically defensible information about best management practices and field management that improve water quality. My climate change program assesses and develops management recommendations that improves climate resiliency in agricultural systems.  Both programs deliver research-based educational programing that seeks to improve the effectiveness of the models we use to drive watershed management and the ensuing management practices to improve water quality or agricultural resiliency.

Current Projects

• Twenty-first century development of 21st century precision agriculture for water quality protection. USDA-AFRI. This project integrates both tool development and stakeholder driven modifications to the tool (see above).

Selected Recent Publications

(*student or postdoc, chronological)

Refereed Publications

• Garna, R.G, D.R. FukaRS, R.R. White, J.W. Faulkner, A.S. Collick*, Z.M. Easton. 2024. Development of a dairy model for the Soil and Water Assessment Tool (SWAT) to direct water quality management of livestock. (In Review).
• Garna, R.G, Z.M. Easton, J.W. Faulkner, A.S. Collick*, D.R. FukaRS. 2023. Employing higher density lower reliability weather data from the Global Historical Climatology Network (GHCN) monitors to generate serially complete weather data for watershed modelling. Hydrological Processes 37(11), e15013. https://doi.org/10.1002/hyp.15013
• Ketterings, Q. C. Twombly, A. Collick*, J. Faulkner, Z.M. Easton. 2024. An evaluation BMP performance using a regional P Index and process-based watershed models. Soil Science Society of America. (In Review).
• Garna, R.G, D.R. FukaRS, J.W. Faulkner, A.S. Collick*, Z.M. Easton. 2023. Watershed model parameter estimation in low data environments. Journal of Hydrology Regional Studies. 45 (2023) 101306. https://doi.org/10.1016/j.ejrh.2022.101306
  
• Stephenson, K., L. Shabman, J. Shortle, Z.M. Easton. 2022. Confronting our agricultural nonpoint source control policy problem. Journal of the American Water Resources Association. https://doi.org/10.1111/1752-1688.13010
• Deval, C., E.S. Brooks, M. Dobre, R. Lew, P.R. Robichaud, A. Fowler, J. Boll, A.S. Collick*, Z.M. Easton. 2022. Pi-VAT: A web-based visualization tool for decision support using spatially complex water quality model outputs. Journal of Hydrology. https://doi.org/10.1016/j.jhydrol.2022.127529
• Fleming, P., K.S. Stephenson, A.S. Collick*, Z.M. Easton. 2022. Targeting for nonpoint source pollution reduction: a synthesis of lessons learned, remaining challenges, and emerging opportunities. Journal of Environmental Management. DOI: 10.1016/j.jenvman.2022.114649
• Modi, P.G, J. Czuba, Z.M. Easton. 2022. Coupling a land surface model with a hydrodynamic model for regional flood risk assessment due to climate change: application to the Susquehanna River. Journal of Flood Risk Management. http://doi.org/10.1111/jfr3.12763
  
• Stamps, S., J. Gallagher, S. Peckham, A. Sheehan, N. Potter, Z.M. Easton, D.R. FukaRS. 2022. Seamless Long-Tail and Big Data Access via the EarthCube Brokering Cyberinfrastructure BALTO. Authorea. doi:10.1002/essoar.10503488.1
• Alamdari, N., P. Claggett, D.J. Sample, Z.M. Easton, M. Yazdi. 2022. Evaluating the joint effects of climate and land use change on runoff and pollutant loading in a rapidly developing watershed. Journal of Cleaner Production. https://doi.org/10.1016/j.jclepro.2021.129953
• Modi, P.G, D.R. FukaRS, Z.M. Easton. 2021. Impacts of climate change on terrestrial hydrological components and crop water use in the Chesapeake Bay watershed. Journal of Hydrology Regional Studies. https://doi.org/10.1016/j.ejrh.2021.100830
• Modi, P.G, D.R. FukaRS, Z.M. Easton. 2021. Data in Short “Impacts of climate change on terrestrial hydrological components and crop water requirement in the Chesapeake Bay Watershed. Journal of Hydrology Regional Studies. https://doi.org/10.6084/M9.FIGSHARE.14049569
  
• Stephenson, K., W. Ferris, E. BockG, Z.M. Easton. 2021. Treatment of legacy nitrogen as a compliance option to meet Chesapeake Bay TMDL requirements. Environmental Science & Technology. https://doi.org/10.1021/acs.est.1c04022
• Fuka, D.R.RS and Z.M. Easton. 2021. TopoSWAT Source. Data in Short. Figshare. https://doi.org/10.6084/m9.figshare.1342823.v4 
• Twombly, C., J. Faulkner, A. Collick*, Z.M. Easton. 2021. Identification of P Index improvements through model comparisons across topographic regions in a small agricultural watershed in Vermont, USA. Soil Science Society of America Journal. http://doi.org/10.1002/saj2.20254
• Hood, R., G. Shenk, R. Dixon, W. Ball, J. Bash, P. Claggett, Z.M. Easton, M. Friedrichs, T. Ihde, L. Linker, A. Miller, G. Noe, K. Rose, J. Testa, R. Tian, T. Veith, L. Wainger, D. Weller, J. Zhang. 2021. The Chesapeake Bay Program management modeling system: progress, challenges, and prospects. Ecological Modeling. https://doi.org/10.1016/j.ecolmodel.2021.109635
  
• Dos Reis B., Z.M. Easton, R.R. White D.R. FukaRS. 2021. A LoRa sensor network for monitoring pastured livestock location and activity. Translational Animal Science. https://doi.org/10.1093/tas/txab010
• Dos Reis B., D.R. FukaRS, Z.M. Easton, R.R. White. 2021. An open-source research tool to study triaxial inertial sensors for monitoring selected behaviors in sheep. Translational Animal Science 4(4):01 Oct 2020. doi.org/10.1093/tas/txaa188
• Dos Reis B., D.R. FukaRS, Z.M. Easton, R.R. White. 2020. An open-source microprocessor-based sensor for monitoring grazing animal behaviors. Journal of Dairy Science 103:9, 0022-0302
• Xu, Y., D. Bosch, M. WagenaG, A. Collick*, Z.M. Easton. 2020. Reducing costs of mitigating nitrogen loadings by within- and cross-county targeting. Journal of Environmental Management. https://doi.org/10.1016/j.jenvman.2020.110333
  
• Wagena, M.B.G, D.G. Goering, A.S. Collick*, E.M. Bock G, A.R. Buda, D.R. FukaRS, Z.M. Easton. 2020. A comparison of short-term streamflow forecasting using stochastic time series, neural networks, process-based, and Bayesian models. Environmental. Modeling & Software. https://doi.org/10.1016/j.envsoft.2020.104669
• Easton, Z.M., E.M. BockG, K. Stephenson. 2020. Feasibility of employing bioreactors to treat legacy nutrients in emergent groundwater. Environmental Science & Technology. http://dx.doi.org/10.1021/acs.est.9b04919
• Bock, E.M.G, and Z.M. Easton. 2020. Export of nitrogen and phosphorus from golf courses in the Mid Atlantic, are current export rates accurate? Journal of Environmental Management.

Extension Publications  (Peer Reviewed)

• Bock, E.M.*, A.S. Collick, and Z.M. Easton. 2018. Managing agricultural drainage quality with denitrifying bioreactors in the Mid-Atlantic (In Press).
• Easton, Z.M., A.S. Collick and E.M. Bock*. 2017. What to consider when considering an agricultural drainage system. BSE-208.
• Easton, Z.M. and J.W. Faulkner. 2016. Communicating climate change to agricultural audiences. BSE-203P.
• Easton, Z.M. and E.M. Bock*. 2016. Soil and soil water relationships. BSE-194P.
• Easton, Z.M. and E.M. Bock*. 2015. Hydrology basics and the hydrologic cycle.  BSE-191P
• Easton, Z.M. and J.W. Faulkner. 2014. Climate change adaptation: Mitigating short and long-term impacts of climate on agriculture. BSE-109P.
• Faulkner, J.W. and Z.M. Easton. 2014. Agricultural adaptation to climate change: improving resilience in row crop production. University of Vermont Extension.Rogers, M.*, E. Lassiter*, and Z.M. Easton. 2014. Greenhouse gas emissions in agriculture: How producers can help to mitigate climate change. BSE-105P.
• Lassiter, E.* and Z.M. Easton. 2013. Denitrifying bioreactors: An emerging best management practice to improve water quality. BSE-55P. http://pubs.ext.vt.edu/BSE/BSE-55/BSE-55-PDF.pdf.
• Easton, Z.M. and E. Lassiter*. 2013. Denitrification management. BSE-54P.

Selected Recent Funding

• 2021: USDA-Cooperative Agreement. Fuka*, D.R., Z.M. Easton, R.R. White. Developing and evaluating rapidly deployable inexpensive weather, soil moisture, shock, and streamflow sensors to aid the monitoring, inspection, and rehabilitation of aging dams. $150,000. June 2021-Nov 2022.
• 2021: USDA-Cooperative Agreement. Easton, Z.M. Modeling the Lake Champlain Basin CEAP watersheds to understand and predict conservation effects on legacy phosphorus. $134,223. Oct 2021-Sept 2023.
• 2021: DARPA-USC. Easton, Z.M. and D.R. Fuka*. Integrating the SWAT Model into the MINT Framework. $64,000. June 2021-Nov 2021
• 2021: Virginia Tech CALS Strategic Plan Advancement. Easton, Z.M., R.R. White, K. Hamed, D.R. Fuka*, M.  Eick. Eyes in the Sky and Boots on the Ground: Collaborative Technologies for Monitoring and Managing Livestock Pastures. $60,000. June 2021-May 2023.
• 2021: NSF CPS (Cyber-Physical Systems). White, R.R., E. Feuerbacher, Z.M. Easton. Collaborative Research: CPS: Medium: Greener Pastures: A pasture sanitation cyber physical system for environmental enhancement and animal monitoring. $998,232. June 2021-Nov 2023.
• 2020: USDA NIFA. Collick, A.S., Z.M. Easton, and R. Bryant. UMES Stormwater Management Research Facility: Investigating nutrient and sediment reduction from poultry house stormwater drainage systems. $399,000. Sept 2020-Aug 2022.
• 2020: NOAA-CBP Easton, Z.M. A Systematic Review of Chesapeake Bay Climate Change Impacts on Tidal and Near Tidal BMPs. $93,400. Oct 2020-Sept 2021.
• 2020: USDA CEAP.  Easton, Z.M., A Conservation Effects Assessment Project (CEAP) Watershed Assessment Study: A collaboration between the University of Vermont, Virginia Tech, the Natural Resources Conservation Service, and the Agricultural Research Service. $179,668. Oct 2020-Sept 2022.
• 2019: US EPA.  Easton, Z.M., R. Najjar, J. Shortridge, K. Stephenson, L. Wainger. US EPA Chesapeake Bay Program. A Systematic Review of Chesapeake Bay Climate Change Impacts and Uncertainty: Watershed Processes, Pollutant Delivery, and BMP Performance. $125,000. Sept 2019-July 2021.
• 2019: VT-CALS. White. R.R., Z.M. Easton, V. Mercadante, D. Ha, G. Morota. VT-CALS. A 2-Year Plan to Establish Sustainable Precision Animal Agriculture Infrastructure at Virginia Tech. $350,000. Sept 2019-Aug 2021.
• 2019: US EPA STAC. Easton, Z.M., K. Stephenson, M. Ribaudo, G. Shenk, P. Fleming, J. Davis-Martin, A.S. Collick. Increasing Effectiveness and Reducing the Cost of Non-Point Source Best Management Practice Implementation: Is Targeting the Answer? A Proactive Workshop. $10,000.
• 2018: USDA-AFRI. Stephenson, K., K. Cobourn, Z.M. Easton. Development and Evaluation of Market-like Pay-for-Performance Programs to Address Legacy Nutrients. $500,000. Dec 2018-April 2022.
• 2017: NSF Earth Cube. Stamps, D. Z.M. Easton, D.R. Fuka*, D. Fuller, S. Peckahm. Collaborative Proposal: EarthCube Integration: Brokered Alignment of Long-Tail Observations (BALTO). $1,695,122. Aug 2017-July 2021.