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INSIGHT: Geographic Information Systems For Environmental Litigation

Sept. 18, 2018, 10:01 AM

In 1908, attorney—and later U.S. Supreme Court Justice—Louis Brandeis pioneered a method of marshaling scientific and quantitative evidence in written legal submissions, an approach that came to be known in legal circles as the “Brandeis Brief.” Rather than relying solely on prior court decisions, which was the traditional form of legal persuasion, Brandeis cited facts and figures, statistics, and other tangible data in support of his argument that the Supreme Court should uphold a statute protecting female workers from exploitation in the workplace. Due in part to Brandeis’ creative, data-based approach, the Court unanimously upheld the statute.

Today, litigators regularly benefit from advances in data collection and analysis technology in persuading audiences. One technology in particular—Geographic Information Systems (GIS)—is capable of providing a wealth of information to a court or jury. This work often involves reviewing, cataloging, and analyzing large volumes of information from disparate sources collected over decades, and even centuries.

GIS is a powerful tool that assimilates layers of spatial (location) data into a database structure to assist in the collection, organization, analysis, and visualization of numerous types of information to explore conditions at a site and the surrounding area at any point in time. Some of this information comes from site-specific documents or investigation reports, but a great deal of GIS-compatible information pertinent to environmental litigation is publicly available from federal entities, (e.g., the Environmental Protection Agency, the United States Geological Survey (USGS), and the National Oceanic and Atmospheric Administration (NOAA) as well as state and municipal entities such as state departments of natural resources or environmental protection, state geological surveys, and town or county assessors’ offices. In fact, many states now have their own GIS data repositories or online mapping environments that allow users to review, download, and utilize a wide variety of GIS information.

Once placed into a GIS database, various data types from numerous sources and time periods can be aligned, cataloged, analyzed, and viewed together. Put differently, GIS can, among other things, collect and apply data to create 2-D and 3-D depictions of information, either at a static point in time or demonstrating migrations and changes over a period of time. In environmental cases, attorneys and experts rely upon testifying experts who use GIS outputs to communicate liability and/or damages arguments to aid the fact-finders in their decision-making.

The utility of GIS is rapidly gaining traction, particularly in the areas of environmental litigation, where understanding the spatial and temporal relationships of environmental conditions is essential to understanding how conditions at a site have evolved, from natural or man-made causes, over time.

Section I of this article outlines the capabilities and limitations of GIS technology. Section II highlights several case studies where the co-authors, GIS professionals at Gradient, describe projects on which they have worked to illustrate the practical benefits GIS can provide in environmental or product liability litigation. Section III discusses several reported litigation matters in which GIS-based testimony was admitted into evidence over the adverse party’s objections.

Section I: Fundamentals of GIS

Database Construction and Management

A GIS database can serve as a centralized data repository for numerous types of information in environmental litigation. Environmental sampling results, aerial or satellite images, historical or contemporary maps and engineering plans, plot and parcel plans, or land surface elevation data can be cataloged and aligned within a GIS database.

Developing a centralized database improves project efficiency in the long run. By enforcing strict data entry rules, problems with datasets can be identified and resolved before the project team relies on the information to draw conclusions. Duplicate information can be identified so that it is added just once. Analyses become more efficient since users need to learn to work with only one data format. A centralized database also keeps the project team in sync because updates are available to all users simultaneously. This in turn will reduce time spent iteratively harmonizing results and conclusions and effectively reduce costs.

A typical GIS database construction process is outlined below.

• Information Review and Cataloging

The first step in developing a GIS database is to identify information and documents for inclusion. Next, the quality of the information is evaluated and noted in the database. The work performed during this phase helps provide information about the scope of the database, including data volume, types, and quality.

• Information Extraction and Compilation

The next step in database construction is to identify details from the source document that should be recorded in the database. Sources of data vary in format (spreadsheets, PDF documents, etc.) and quality (completeness, legibility, etc.), and extracting data accurately and efficiently requires careful planning. Details that are extracted need to be standardized to match the database architecture. For example, when extracting information from a site investigation report where environmental samples have been analyzed, GIS professionals include specific elements such as sample date, measurement method, sample media, location, and measurement result. Efficiency can be improved by writing computer code to parse information and/or by utilizing character recognition tools to extract information from PDF documents.

After extraction, each data element must be standardized before it is added to the database. For example, the following elements typically need to be harmonized: result qualifiers, such as signifiers of results below laboratory detection limits; sampling methodology used through time; chemicals of potential concern identification; units of measurement; and sample matrices (e.g., soil, sediment, water, etc.).

• Location Information

The information compiled into a GIS database can be tagged to a location (latitude/longitude, X/Y coordinates) and elevation. It is therefore important to obtain accurate spatial information from the source documents.

Occasionally, source material will report accurate spatial information in an electronic file or pre-existing GIS-compatible files, which can be uploaded to the database with minimal effort. When geographic information is not provided in the source document, this information can be added through georeferencing procedures. Georeferencing is a technique for aligning a digital image with north and east in a ground coordinate system by selecting ground control points (GCPs), which are features that can be clearly identified and matched to known locations in the source image. The GIS database also includes tools to evaluate the accuracy of the georeferenced image.

• Quality Control

Quality control (QC) procedures are essential to the database construction process to ensure the accuracy of the information in the final database. Such procedures are performed in each phase, and the information is checked against the original source document. This also is essential to satisfy evidentiary standards applicable to expert testimony in environmental litigation.

Data Mining and Analysis

Once the GIS database has been constructed and the information passes QC, it can be used to perform data analyses to support a variety of project objectives while ensuring that project team members or litigation experts are relying on the same base information. A GIS database can be used to facilitate spatial analyses (e.g., land-cover changes or contamination delineation), temporal analyses (e.g., time series trend analysis), and statistical analyses (e.g., exposure concentration estimates).

Visualization and Data Communication

GIS offers flexibility in generating well-constructed data visualization that enhances the communication of facts. GIS can be used to create web-based mapping tools where users can select layers of data and apply filters to explore the information.

In addition, GIS can be enabled on mobile devices to help collect data in the field (e.g., notes, photographs, points of interest) that can then be uploaded directly to a centralized GIS database. Since GIS visualizations are based on a database structure, they can be updated quickly when new data are available.

GIS software can be used to create impressive animations or 3-D drawings of output from models. GIS maps also can be used as powerful and informative demonstratives or figures that can be displayed at trial or used as figures in an expert report.


With the massive amount of information usually available in environmental litigation, building an accurate GIS database from numerous and often disparate historical or contemporary documents is a time-consuming process. However, investing in a GIS database will reap long-term rewards as experts can rely on a single harmonized, quality-controlled, data set.

GIS is normally only one piece of a good environmental data management program. GIS databases are inherently limited by the quality of the information on which they were constructed. Limitations derived from disparate historical or contemporary documents can, however, be assessed by a GIS professional to estimate uncertainty in spatial and historical accuracy. Finally, while GIS can help to accurately interpolate between known data sets, it is not often used for predictive modeling or forecasting.

Section II: Practical Uses of GIS—Case Studies

Case Study 1. For an insurance claim related to an agricultural chemical, Gradient evaluated the relationship between historical applications and more recent detections in groundwater and surface water throughout the United States. Gradient utilized a GIS database to compile and evaluate chemical concentrations in water and physical characteristics of the surface and subsurface hydrologic systems and of the water supply systems. The database comprised analytical data for over 30,000 groundwater and surface water sampling locations collected over a 75-year period. In addition to the analytical data, Gradient also incorporated streamflow data and analyzed aerial images to describe historical land use and land cover changes through time within the GIS environment. The analysis illustrated the extent to which chemical applications can contribute to chemical detections in groundwater and surface water during defined periods after the application.

Case Study 2. For a Clean Water Act litigation project, Gradient reviewed and analyzed historical aerial photographs and digital topographic information to evaluate terrain and land cover changes that occurred on, and in the vicinity of, a site from the 1930s to the early 2000s. This information was compiled within a GIS database to facilitate the analysis of time-series land cover changes to the site and its vicinity and interpret the locations of gullies and engineered drainage features through time.

Case Study 3. In support of a mediation for allocating remedial costs associated with a regional contaminant plume downgradient of a former industrial complex, Gradient provided technical evaluation related to the sources, release timing, and fate and transport of contaminants in the subsurface, focusing on their plume contributions. Gradient reviewed historical environmental investigations and other records dating back to the 1930s to develop a comprehensive database of multimedia sampling data, hydrogeologic information, and aquifer demand. This database was critical to help develop: (1) a conceptual model of contaminant release and migration in groundwater, as well as 3-D representations using environmental visualization system (EVS) software to illustrate plume evolution over time; and (2) 3-D renderings of the data and web-based mapping solutions to help communicate results to the client and the mediator.

Case Study 4. For a product liability case involving the presence of chemicals in surface water bodies, Gradient analyzed the fate and transport pathways of these chemicals from their points of use to the water body. Gradient used a database to compile decades’ worth of sampling from the watershed and identified multiple sites throughout the watershed that could have contributed chemicals to the surface water body. Gradient reviewed and analyzed aerial photography and satellite-derived data to evaluate the land cover for numerous sites. This information, along with multimedia sampling information and other pertinent geographic data throughout the watershed, was compiled in a GIS database. Gradient developed web-based and mobile-based GIS applications to help communicate and collect information. The work helped the client identify the actors and actions that caused chemical discharges within the watershed.

Section III: Admissibility and Use of GIS in Litigation

Courts have deemed GIS to be an effective tool in environmental litigation when: (1) it is introduced by a qualified expert; (2) it is a good “fit” for the case; and (3) the methods employed are reliable. Litigators have used GIS to successfully argue causation as well as damages, and in some cases, to demonstrate violations of environmental regulations. While the reported litigation matters discussed below focus on cases where plaintiffs successfully sought to introduce GIS evidence at trial, GIS should be considered a valuable tool for defendants as well.

A. Causation

Causation refers to whether a defendant’s conduct caused harm.

The U.S. and the State of South Dakota initiated an action against Black Hills Power, Inc., for negligence, trespass, and nuisance based on a forest fire near Grizzly Gulch in the Black Hills of South Dakota in U.S. v. Black Hills Power, Inc. A key factual dispute was whether the defendant’s electricity conductors started the Grizzly Gulch fire.

The government expert, a GIS specialist for the U.S. Forest Service, created a series of 3-D maps and a computer-based animation clip that depicted the area of the Black Hills burned by the fire. The expert created a 3-D map from a 1972 aerial photograph of the area where the Grizzly Gulch fire later started. Using industry-standard GIS software, he overlaid the photograph on a digital model of the elevation of the land created by USGS. He also created a 3-D map using an aerial photograph taken in 2000 (pre-fire), and then created two more 3-D maps of the area during the fire using infrared satellite photographs while the fire was burning. The expert also created four additional 3-D maps from an aerial photograph taken in 2002 (post-fire). In conjunction with each of the 3-D maps, the expert created a computer-based animation clip so that the viewer could experience “flying over” the impacted area.

Over the defendant’s objections, the court allowed the expert to testify because the 3-D maps were evidence that would help the jury understand the complex, factually intense, matters that would enable them to decide whether the defendant’s electricity conductors started the fire.

B. Damages

If a court or jury finds that causation has been proven, then it must next address what damages must be paid to compensate the harmed individual(s).

In 2006, a group of property owners commenced an action against the former operators of the Rocky Flats Nuclear Weapons Plant for nuisance and trespass in Cook v. Rockwell Int’l Corp. To establish their damages, the plaintiffs retained an expert to testify about a market-impact analysis he had conducted to assess the effect of proximity to the Rocky Flats Nuclear Weapons Plant on their property values.

The expert developed several computerized models to identify, quantify, and explain differences in the value of properties near Rocky Flats and properties located elsewhere in the area. Employing his expertise in GIS and spatial modeling, the expert also developed and incorporated additional variables relating to location-based characteristics of the property, such as neighboring land use, employment levels, demographic data, crime and poverty, traffic volume, accessibility to open space, topography, and commute time to employment and other locations.

Over the defendant’s objections, the court permitted the expert’s testimony to be admitted into evidence based in part on his undisputed expertise in GIS, spatial modeling, and computing, and his ability to rely on GIS to assist the jury in understanding the amount of damages to award the plaintiffs.

C. Regulatory Compliance

The U.S. employs GIS to assist with the prosecution of regulatory violations.

In 2001, the U.S. brought an action against the creators of an earthen dam, claiming that the dam’s impoundment of water violated the Clean Water Act in United States v. Roberts. The U.S. retained an environmental scientist to opine that a decades-old stream existed at the dam site prior to and up until the construction of the dam. The scientist reviewed 14 aerial photographs of the area from 1953 through 2010 under various magnifications to analyze the features and conditions appearing on the photographs. He used GIS to geographically reference and overlay the photographs so that the same locations could more easily be examined across the various photographs under consideration, to examine specific features close up, and to look at the stream in the context of the surrounding landscape. Over the defendants’ objection, the court admitted the scientist’s testimony into evidence.


Litigants in environmental and product liability are increasingly relying on the benefits of GIS technology to advance their cases. A GIS database is capable of assisting litigators and litigation experts to achieve a variety of goals, including developing a theory of the case, creating demonstrative exhibits for fact-finders, establishing liability, or proving damages. Attorneys should be mindful, however, that GIS is only as good as the controls established when initially developing the database to ensure reliability. Similarly, attorneys should ensure that retained experts are sufficiently experienced with the technology before relying on it in court. Nonetheless, the cost of creating a GIS database, mitigated in part by the wealth of publicly available resources that can be mined for underlying data, is often well-justified when this powerful tool is used appropriately.

Jonathan I. Handler is a partner at Day Pitney LLP whose practice in complex commercial litigation involves the representation of corporate clients and individuals in tort and contract disputes. He has represented clients in state and federal courts in a wide variety of disputes, including matters involving complex product liability, accounting malpractice, unfair and deceptive trade practices, mergers and acquisitions, and tortious interference. He also counsels corporate clients in a variety of industries, including specialty chemicals and aerospace, on ways to mitigate risk and avoid litigation.

Sylvia-Rebecca Gutierrez, an associate at Day Pitney LLP, represents corporate clients in a variety of disputes, including in the areas of labor and employment litigation, legal malpractice, tort, and real estate tax litigation. Her experience includes defending manufacturers in mass tort personal injury suits alleging asbestos or other toxic exposure.

Matthew J. Mayo, M.S., GISP, CPG, P.G., is a senior GIS/environmental scientist at Gradient, an environmental and risk sciences consulting firm. He is a certified Geographic Information System (GIS) professional and licensed professional geoscientist with expertise in GIS database construction and analysis, 2D and 3D spatial modeling, and remote sensing. His work focuses on analyzing imagery and GIS data for projects related to hydrology, exposure assessment, cost allocation, historical operations, and contaminant fate and transport. He has been retained as an expert in aerial and satellite imagery and GIS data analysis for clients involved in environmental litigation.

Maggie Pollock, M.S., is a senior environmental scientist at Gradient who specializes in quantitative data analysis, data coding, and database development to support a wide range of environmental projects including hazard assessment, exposure assessment, cost estimation, and historical operations. She has been instrumental in developing interactive information management tools to summarize literature reviews and to streamline information collected in toxic tort litigation.

The opinions expressed here do not represent those of Bloomberg Environment, which welcomes other points of view.