Nathan Epler, PhD, PG, LEP

Principal Hydrogeologist



Quantitative Hydrogeology

Geochemistry and Emerging Contaminants

Environmental Forensics

Environmental Project Management

Expert Witness/Litigation Support Pertaining to the Fate and Transport of Environmental Contaminants in Soil, Soil Vapor, and Groundwater

Project Manager for Remedial Investigations, Feasibility Studies, and Remedial Actions

Redevelopment of Brownfield, Petroleum Spill, and MGP Sites


PhD, Hydrogeology - State University of New York at Stony Brook

MS, Geology - State University of New York at Stony Brook

BS, Geology - Queens College, City University of New York

Nathan Epler, PhD, PG, LEP

Principal Hydrogeologist

Dr. Nathan Epler is a Principal Hydrogeologist with Roux, having 30 years of experience in site assessment, site remediation, and chemical fate and transport evaluations and modeling. He holds a Ph.D. in Groundwater Geochemistry from the State University of New York at Stony Brook, an M.S. in Geology from the State University of New York at Stony Brook, and a B.S. in Geology from the City University of New York at Queens College. Dr. Epler has extensive expertise in evaluating the timing of releases, geochemistry of groundwater including emerging contaminants, fate and transport of environmental contaminants, including LNAPL and DNAPL. Dr. Epler has managed remedial investigations at major industrial facilities, petroleum refineries, Manufactured Gas Plant, and Brownfield redevelopment sites throughout the United States. He has designed and supervised the installation of large-scale remedial systems at Superfund Sites throughout the northeast. He has prepared—and gained regulatory acceptance of—groundwater models for Industrial Site Recovery Act (ISRA) Sites in New Jersey, Federal Superfund sites, and large petroleum terminal and industrial sites, including sites impacted by mixed plumes of volatile organic compound (VOC) contamination. Dr. Epler has been a guest lecturer at Columbia and New York Law Schools, the American Law Institute and American Bar Association Environmental Litigation conferences, published with the American Bar Association, and served on panel discussions for the American Bar Association’s Dispute Resolution Section Annual Conferences. He has deposition and mediation experience.

representative projects
  • Project Manager, site investigation and remediation at a bulk petroleum storage terminal in New York. Project included soil borings and installation of wells to delineate free-product plume. Successfully negotiated with NYSDEC regarding scope and design of active free-product recovery system.
  • Project Manager of site investigation and redevelopment project for 10 parcels in Manhattan. Sites were impacted by MGP waste and petroleum hydrocarbons. Site remedies included installation of sheet-piling containment barriers, and incorporation of vapor barrier and active venting systems into building construction.
  • Project Manager of groundwater remedial investigation at an ISRA site in New Jersey. Project included installation of over 120 monitoring wells to delineate off-site plume of chloroform and pesticides in groundwater, and the installation and testing of a 1,500-gallon per minute interceptor/recharge system to capture the plume.
  • Project Manager, site investigation and remediation at a NYS Superfund Site in Glen Cove, New York. Project included performing remedial investigation to identify the nature and extent of impacts to soil and groundwater, and developing and implementing a remedial action plan.
  • Project Manager, remedial investigation at a New York State Superfund Site. Site was a former dye and pigment manufacturing facility for over 100 years. Extensive soil and groundwater contamination by arsenic and VOCs were delineated and remediated under a series of Interim Remedial Measures (IRMs) designed to be coordinated with the future redevelopment of the Site.
  • Project Manager, remedial investigation under the New York State Voluntary Cleanup Program of a closed industrial landfill. Site was contaminated with numerous compounds and contained drums and construction debris. Site was evaluated using electromagnetic surveys, trenching, and borings. Remedial action work plan included using phytotechnology to address leachate control.
  • Principal Modeler, surface water flow, solute, and sediment transport in a river adjacent to an 850-acre petroleum terminal. Dissolved phase hydrocarbon fluxes into the river were calculated based on a groundwater flow model. The fluxes were used as input into a 2D finite element river model. The river model was used to predict the maximum downstream transport of dissolved phase and sediment borne contaminants.
  • Principal Modeler, light non-aqueous phase liquid (LNAPL) recovery simulations using finite-element modeling. Recovery simulations were performed to evaluate the feasibility of recovery of a benzene plume at an industrial facility in Brazil. The modeling results indicated that LNAPL recovery alone would be inadequate to remediate the plume. Air sparging and soil vapor extraction were proposed as alternatives.
  • Principal Modeler, groundwater flow and solute transport at an industrial site on Long Island, New York, where groundwater is impacted by hexavalent chromium which threatens public water-supply wells downgradient of the Site.
  • Principal Modeler, groundwater and surface water flow and contaminant transport at a Superfund Site in New Jersey. Groundwater contaminant fluxes based on a 3D groundwater flow model are used to provide input into a 2D finite element surface water model of a tidally-influenced creek and wetlands system. The combined models are used to study the flux of contaminants through the groundwater/surface water flow system.
  • Principal Modeler, groundwater flow and remedial design at a Superfund site in Delaware impacted by VOCs. Performed dense non-aqueous phase liquid (DNAPL) investigation. Designed remedial system consisting of 12 interceptor wells.
  • An NRD claim for a large agrochemical facility in central New Jersey was avoided by creating a closed-loop pumping/treatment and reinjection system that resulted in no net loss of resource for the primary potable water supply aquifer. In addition, a supply well that was threatened by the off-site plume was shut down and replaced.

  • Expert Witness for former service station owners in Westchester, NY defending against claim of impact to adjacent private properties. Demonstrated that additional third-party defendants were equally responsible for impact.

  • Gross v. Pall Corporation. Expert Witness for Long Island industrial site. Successfully defended third-party against claim that they contributed to off-site contamination of a public supply well. Case settled prior to trail.

  • Expert Witness for upstate New York industrial site where residents were claiming indoor air impacts occurred due to migration of chlorinated solvents in groundwater along sewer lines. Used historic release data and GIS interpretation of chemical signatures to demonstrate that additional responsible parties likely contributed to contamination, which were not named in the original complaint.

  • Expert Witness for an insurance carriers’ defense group. Provided expert report concerning the timing of groundwater contamination. Case settled prior to deposition.

  • Major et al. and Green et al. v. AstraZeneca Inc., et al. Expert Witness for upstate New York industrial site. Provided litigation support on case involving a former industrial dump site where wastes were burned and whether migration from the site could have impacted surrounding domestic supply wells. Case settled prior to deposition.

  • FMC Corporation v. The Vendo Company and Wier Floway, Inc. Consulting Expert for plaintiff. Reviewed groundwater fate and transport model created by defendants. Model was shown to be flawed, inaccurate, and invalid according to generally-accepted modeling practices. Case settled prior to deposition.

  • Consulting expert for Fortune 500 corporations group related to the Passaic River/Newark Bay Superfund Site.

  • Consulting expert reviewing groundwater model for Newtown Creek Superfund Site.

  • Testifying expert for Gowanus Canal Superfund Site small party defendant.

  • Testifying Expert for a Natural Resources Damage case involving impacts to public supply wells on Long Island.

  • Consulting expert evaluating groundwater fate and transport model for large groundwater plume impacting supply wells on Long Island.

  • Expert Witness for water district impacted by a Superfund Site on Long Island, New York. Provided opinions on source and timing of VOC plume and apportionment.

  • Consulting Expert to provide opinions on impact of product release at a petroleum terminal relative to existing impacts.

  • Consulting Expert to provide opinions on nature and timing of pipeline release.