About

Stanley Grant is a Professor of Civil and Environmental Engineering at Virginia Tech and serves as the Director of the Occoquan Watershed Monitoring Lab (OWML) in Northern Virginia. His research focuses on pollutant fate and transport through aquatic systems, with particular interest in water supply and water quality, environmental fate and transport modeling, and coupled human-natural systems. Professor Grant and his team have been awarded a $3.6 million NSF-funded Growing Convergence Research grant to study novel approaches for managing inland freshwater salinization.

Research topics

• Computer Science
• Geography
• Water resource management
• Environmental science
• Ecology
• Environmental planning
• Biology
• Soil science
• Economic growth
• Business
• Geochemistry
• Finance
• Economics
• Engineering
• Geology
• Geotechnical engineering

Selected publications

• Social-ecological-technological drivers of freshwater salinization in the Occoquan Reservoir, United States

  Communications Earth & Environment · 2026-01-05 · 2 citations

  articleOpen access1st authorCorresponding

  Freshwater salinization is an emerging and largely unregulated threat to drinking water security. We identify three dominant, seasonally distinct sources of rising sodium in a drinking water supply serving 1 million people: (1) road deicers, which elevate reservoir sodium in winter, with detectable impacts at watershed impervious cover as low as 3%; (2) reclaimed water, which increases sodium during summer low flows when dilution is minimal; and (3) the drinking water treatment plant (DWTP), which adds NaOH to neutralize acidity from coagulation and in-reservoir microbial processes. In this social-ecological-technological system (SETS), salinization is tied to population growth, impervious cover, sodium-rich waste streams, nitrogen management, reservoir biogeochemistry, and DWTP operations. Framing drinking water salinization as a SETS challenge integrates behavioral and biophysical drivers with engineering and governance responses, providing a framework for adaptation in One Water systems. Long-term monitoring reveals that rising sodium concentrations in a large One Water drinking water supply arise from road salts, reclaimed water, and treatment chemicals, highlighting freshwater salinization as a socio-ecological-technological challenge.

  PublisherOA PDFDOI

• From PFAS source attribution to collaborative management in a One Water system

  Research Square · 2026-03-18

  preprintOpen access1st authorCorresponding
  PublisherOA PDFDOI

• Collaborative Communities, Brokers, and Integrators in a Convergence Research Team: A Social Network Analysis

  Minerva · 2026-05-21

  articleOpen accessSenior author

  Abstract We used Social Network Analysis (SNA) and self-reported measures of transdisciplinary orientation to uncover the types of collaborative communities, broker, and integrator roles that emerged in a large convergence research team and examined how these communities and roles correspond to team members’ network positions and orientations. We modeled an undirected, weighted collaboration network using twenty team members’ levels and frequencies of collaboration with peers and contextualized the network patterns with open-ended responses on team dynamics. We overlaid community detection and node-level metrics (degree, betweenness centrality, clustering coefficient) with team members’ disciplinary backgrounds, cross-disciplinary ties, and transdisciplinary orientation. We identified three collaborative communities: a leadership core of experienced integrators , mentor-mentee pairs, and domain anchors who provide technical expertise. Broker ( major brokers, information carriers, satellite collaborators ) and integrator ( cross-cluster, hidden, within-cluster, narrow ) role classification revealed that boundary spanning depends on the interplay of personal orientation, opportunity, and project context. Influence was distributed beyond formal leadership, boundary spanning was not determined by seniority, and subgroup expertise and between-group reach reinforced each other. We outline practical applications of SNA for the evaluation and design of scientific teams that aim for knowledge integration across disciplinary boundaries.

  PublisherOA PDFDOI

• Nature Water

  VTechWorks (Virginia Tech) · 2026-01-01

  articleSenior author

  A major barrier to preventing per- and polyfluoroalkyl substances (PFAS) from entering drinking water supplies is identifying and quantifying their upstream sources, particularly in One Water systems that integrate diverse water inputs. Here we combine high-frequency measurements with mass-balance analysis to quantify PFAS and major-ion loading to the Occoquan Reservoir, a drinkingwater supply serving one million people in Northern Virginia, USA. Mass-balance analysis at the confluence of watershed inflows and treated wastewater inputs reveals seasonally varying contributions from domestic wastewater, watershed runoff, and a single significant industrial user (SIU) of the sanitary sewer system. A one-month, system-scale diversion of SIU effluent confirms this source attribution for several short-chain PFAS and major ions, with concentration deficits closely matching withheld mass. These results demonstrate that traditional mass-balance approaches can inform collaborative management of PFAS contamination in One Water systems.

  Publisher

• Watershed Continuum Monitoring Approach: combining multiple water quality patterns along stream and river flowpaths to track sources, pathways, and processing of pollutants

  Ecological Engineering · 2026-05-12

  articleOpen access
  PublisherDOI

• Transit time modeling framework for predicting freshwater salinization in urban catchments

  Water Research · 2026-03-04

  articleOpen access

  when normalized by the 20,000 people living in the watershed. In winter months, higher infiltration routes a large fraction of snowmelt and deicers into shallow subsurface pathways, enhancing vadose-zone and interflow contributions to stream salinity. Limited subsurface storage capacity and seasonal hydrologic turnover flush excess chloride from the vadose zone and groundwater during subsequent summer storms. By linking climate-driven deicer inputs, hydrologic connectivity, and stream water age, the framework provides a transferable basis for diagnosing and managing freshwater salinization in urban watersheds.

  PublisherDOI

• Collaborative Solutions to Inland Freshwater Salinization

  Research Square · 2025-05-22

  preprintOpen access1st authorCorresponding
  PublisherOA PDFDOI

• Transit times link pollution sources to drinking water quality in a “One Water” system

  Water Research · 2025-09-27 · 5 citations

  articleOpen accessCorresponding

  Innovative approaches are needed to manage chronic and emerging water quality challenges in communities that rely on treated wastewater and urban stormwater as sources of raw water for drinking water treatment, or “One Water” systems. When amended to account explicitly for upstream versus distributed inflow to the reservoir, we show that unsteady transit time theory links pollution sources to water quality in the Occoquan Reservoir (Virginia, USA), one of the largest and oldest One Water systems in the United States. Using 11 years of hydrologic and water quality data, the model identified distinct sources and transformation rates for reactive (nitrate) and relatively non-reactive (sodium, chloride) solutes. High predictive skill was achieved with a strikingly small number of parameters: two for sodium and chloride (one for the upstream storage selection function, one for solute input from distributed sources; Nash–Sutcliffe Efficiency (NSE) = 0.65 and 0.76) and two additional for nitrate (capturing seasonal denitrification linked to summer stratification and hypolimnetic processes; NSE = 0.55). The simplicity of unsteady transit time theory supports rigorous parameter estimation (Bayesian Markov Chain Monte Carlo) and model structure evaluation (Bayesian Information Criterion). It also opens the door to real-time interactive simulations with stakeholders, supporting collaborative solutions to cascading water quality challenges. • Transit time theory describes the fate and transport of pollutants in a drinking water reservoir. • Upstream sources are described by a shifted-uniform storage selection function. • Distributed sources are described by a uniform storage selection function. • Water quality at the drinking water intake is accurately predicted with few model parameters. • Transit time theory supports real-time water quality simulations for collaborative One Water management.

  PublisherDOI

• Decision rules for salt –feedback loops in One Water systems and their implications for collective management

  Global Environmental Change Advances · 2025-09-01 · 1 citations

  articleOpen access

  Freshwater salinization is an emerging challenge that threatens ecosystem health and drinking water security. Coordinated action is necessary to address this challenge, but is often hampered by fragmented management of water subsystems that does not consider the feedback loops between them. This study uses surveys, interviews, and fuzzy cognitive maps (mental models that capture important system concepts and relationships) to characterize stakeholder perceptions of feedback loops between water subsystems and their implications for salt management. We use Virginia’s Occoquan Reservoir, a salinizing “One Water” system where wastewater, drinking water, and stormwater are coupled and the need for integrated management is great, as a test case, focusing on (1) the prevalence of feedback loops in stakeholder mental models of salinization, (2) the existence of decision rules - feedback loops that bridge social and natural subsystems and constitute potential levers for managing salt, and (3) the extent to which aggregating multiple mental models generates “wiser” decision rules. Our results suggest that while stakeholders perceive relatively few feedback loops and decision rules individually, collectively they resolve a dynamic and interconnected system. Aggregating multiple perspectives revealed over 450 decision rules, not all of which made sense to individuals. Sense-making depended more on the content of decision rules than their length or dynamics. Stormwater subsystems were absent from all decision rules, highlighting a gap in systems understanding that could hinder effective management. Creating opportunities for cross-agency communication and shared learning could help bridge such gaps, supporting collective governance in One Water systems like the Occoquan. • Social-ecological feedback loops capture decision rules for managing salinization. • Decision rules are rarely recognized by individuals but emerge in aggregate. • Not all decision rules make sense, reflecting misspecified processes and bias. • Emergent rules bridge wastewater and drinking water subsystems, but omit stormwater. • Cross-agency communication/learning is needed to support collective salt management.

  PublisherDOI

• Toward a universal model of hyporheic exchange and nutrient cycling in streams

  2025-03-15

  preprintOpen access

  Transformation and removal of dissolved nutrients and pollutants in streams strongly depends on microbial processes in streambed sediments. The contact between these solutes and microbial communities is mediated by the physical transport from the bulk stream to, and through, the streambed, a process broadly referred to as hyporheic exchange. Even though multiple physical and biological processes influence the rate of hyporheic exchange, we here show that many hyporheic exchange mechanisms can be represented simply as a one‐dimensional diffusion process, where the diffusion coefficient decays exponentially with depth into the streambed. This framework is applied to a classic study of nitrate removal in 72 headwater streams across the United States, showing how the interplay among land‐use, stream physics, and stream biology collectively influence nutrient transformation in streambeds. The proposed modeling framework can help the upscaling of hyporheic exchange and promote better understanding of its role for processing and removal of contaminants in streams.

  PublisherDOI

Recent grants

• Planning Grant: Engineering Research Center for the Global Environment Nutrient Network (GEN-2)

  NSF · $100k · 2018–2021

• CAREER: The Coagulation and Gravitational Settling of Particles in Aqueous Environments

  NSF · $300k · 1995–2001

• Collaborative Research: GCR: Common Pool Resource Theory as a Scalable Framework for Catalyzing Stakeholder-Driven Solutions to the Freshwater Salinization Syndrome

  NSF · $2.0M · 2020–2026

• PIRE: Low Energy Options for Making Water from Wastewater

  NSF · $4.9M · 2012–2018

Frequent coauthors

• Megan A. Rippy

  Waters (United States)

  163 shared

• Sujay S. Kaushal

  Earth System Science Interdisciplinary Center

  72 shared

• Shantanu V. Bhide

  53 shared

• Jong Ho Ahn

  49 shared

• Brett F. Sanders

  Irvine University

  46 shared

• Sunny C. Jiang

  45 shared

• J. D. Gomez‐Velez

  Oak Ridge National Laboratory

  44 shared

• Emily A. Parker

  Centre for Sustainable Healthcare

  44 shared

Labs

• Occoquan Watershed Monitoring Lab (OWML)PI

Education

• PhD, Environmental Engineering Science

  California Institute of Technology

  1991

• Geology with Distinction, Geology

  Stanford University

  1985

Awards & honors

• NSF-funded Growing Convergence Research grant