June 01, 2013

Using Aerial Photography, Geospatial Data, and GIS to Support the Enforcement of Environmental Statutes

Peter Stokely

Aerial photography interpretation combined with geospatial or other “collateral” data and Geographic Information Systems (GIS) analysis are established and litigation-tested tools used to support the investigation and enforcement of environmental laws and regulation. Two laws discussed in this article, the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA), 42 U.S.C. 9601–9675, and the Clean Water Act (CWA), 33 U.S.C. 1251 et seq., provide for the protection of environmental or human health from pollution originating from fixed geographic locations, and are well suited to be supported using aerial photography interpretation, geospatial data, and global information systems (GIS).

CERCLA, enacted by Congress on December 11, 1980, and commonly known as Superfund, created a tax on the chemical and petroleum industries and provided broad federal authority to clean up hazardous waste sites (Superfund site) that may endanger public health or the environment. A Superfund site is defined as an uncontrolled or abandoned place where hazardous waste is located. Thus, by definition, a Superfund site is a fixed geographic place ideally suited to study with aerial photography and GIS. Superfund sites have indicative features and conditions that can be seen and interpreted from aerial photography, and most importantly, historical aerial photography, and mapped using GIS software. Superfund site features and conditions are quite varied, ranging from obvious features such as large waste lagoons and massive drum disposal areas, to subtle scars on the landscape seen on historical aerial photography as the latent signature of buried wastes.

The CWA, which came into being under its current name in 1972, establishes the basic structure for regulating discharges of pollutants into the waters of the United States. 33 U.S.C. § 1251 et seq. (1972). Waters of the United States include our nation’s streams, rivers, lakes, oceans, estuaries, and wetland areas. Specifically, the CWA made it unlawful to discharge any pollutant from a point source into navigable waters, unless a permit is obtained. 33 U.S.C. §§ 1311, 1362. A point source (“any discernible, confined and discrete conveyance . . .”) is a fixed geographic location where pollution can be found, and thus is ideally suitable for study using aerial photography interpretation and GIS. Pollutants under the CWA include industrial and municipal waste, as well as dredged or fill material. CWA cases are also rich in facts that can be identified and described using aerial photography interpretation, geospatial data and mapping that document features such as topography, slope, drainage patterns, the locations of wetlands, and the presence and chronology of the deposition of dredged or fill material.

Aerial photography interpretation can be defined as the art and science of examining and evaluating aerial photography for objects, features, or conditions, and evaluating their significance. Aerial photography interpretation is used to identify and map soils, forest types, wetland extent, land use, land cover, tree canopy cover, the locations of animal feedlots, or to pin down the location of historical pollution events and sources, to name just a very few examples. Aerial photography is obtained from a variety of sources including, but not limited to, the U.S. Geological Survey (USGS), the Department of Agriculture’s Aerial Photography Field Office (APFO), state data warehouses, private vendors, and directly from companies that fly the aerial photography. Today a simple Google search on the terms earthexplorer, APFO, state X-geospatial, or aerial photography companies in state X, will frequently yield enough sources of aerial photography, frequently at no cost, to get started on any interpretation and mapping project. Furthermore, aerial photography is often available in file formats that allow for the accurate placement of the photography in a GIS map where it can be easily compared with other geographical data.

A GIS integrates computer hardware, commercial (or open source) software, and data, for capturing, managing, analyzing, and displaying all forms of geographically referenced information. (Definition adapted from Environmental Systems Research Institute web-based learning site. The organizing principle of GIS is geographic location; the map view is where geo-referenced data can be viewed and worked with. GIS allows the user to view on a computer screen geographic data in a way that reveals relationships between the data (proximity, overlap) as well as spatial patterns and temporal trends in the data. GIS helps the analyst look at multiple data sets in a way that is quickly understood and easily shared. Google Maps or Google Earth are simple GISs where ATMs or restaurants (point data) can be overlain with roads (line data) on top of aerial photography or satellite images.

Geospatial data is information that identifies the geographic location and characteristics of natural or constructed features and boundaries on the earth, and is typically represented by points, lines, and polygons. EPA, National Geospatial Data Policy (August 2005). Geospatial data comes in file types that can typically only be read and utilized by GIS software. The points, lines, and polygons that represent features and boundaries data can be created by an analyst using GIS software by a process known as digitizing. For example, an aerial photography interpreter can identify and map the boundaries of a wetland area from the aerial photography, and use the GIS software to create a digital file that represents the boundaries. The digital file can be attributed with information about the feature such as the wetland type, size, or other relevant factors. The geographic nature of the file allows it to be overlain on other GIS maps or geo-referenced aerial photography or with other geospatial data such as stream flow lines. This overlaying of a wetland boundary with past and current aerial photography will show any changes, and the types of changes, to the wetland area over time.

Geospatial data can also be created in the field using a global positioning satellite (GPS) device. For example, the GPS can be used to record the locations of fire hydrants or street lights in a city, or sample points in a field study site. The recorded GPS points are then read directly by the GIS software and placed on a map or image backdrop for display purposes and further analysis. Existing off-the-shelf geospatial data is widely available and can also be obtained from many of the same sources identified in the aerial photography discussion above. For example, the USGS offers to the public and professional user, at no cost, vast quantities of geospatial data representing stream flow paths, lines of elevation, roads, place names, cultural features, and more. Many states also have geospatial data warehouses where the data can be downloaded for free. When considering the use of aerial photography and geospatial data, it is important to note that current data often may not be the most relevant to a CERCLA or CWA case. Historical data, such as historic aerial photography or old maps, are indispensable for identifying and mapping objects, features, or conditions that have long since disappeared from the landscape. In many instances, historical aerial photography is the only data source about past environmental conditions and can help catch a polluter or identify a past pollution source.

In federal court enforcement cases, the admissibility of aerial photography interpretation and GIS mapping into evidence is governed by the Federal Rule of Evidence 702, which covers the admissibility and testimony of a potential expert witness in Federal Court. Rule 702 states that a witness who is qualified as an expert by knowledge, skill, experience, training, or education may testify in the form of an opinion or otherwise if: the expert’s scientific, technical, or other specialized knowledge will help the trier of fact to understand the evidence or to determine a fact in issue; the testimony is based on sufficient facts or data; the testimony is the product of reliable principles and methods; and the expert has reliably applied the principles and methods to the facts of the case.

The basic standards for satisfying Rule 702 were developed by the Supreme Court in the now-famous case Daubert v. Merrill Dow Pharmaceuticals, 509 U.S. 579 (1993). In Daubert, the Supreme Court held the standard to be an essential component of the U.S. Federal Rules of Evidence, and announced that the trial judge was required to act as a gatekeeper before admitting evidence, and must determine that the evidence is scientifically valid and relevant to the case at hand. Before or during a trial, parties can request a hearing in front of the judge to determine if a designated expert meets the Daubert Rule 702 standards: whether the methods and potential testimony are “junk science” and should be excluded from the trial, or whether it is “relevant to the task at hand” and that rests “on a reliable foundation” and is the product of sound “scientific methodology.” This article will present two case studies of how aerial interpretation, geophysical data, and GIS analysis have been used as evidence and expert testimony in CERCLA and CWA enforcement cases.

A Reliable Foundation

Aerial photography and its interpretation has a long and creative history starting with hot air balloons, kites, and even carrier pigeons as early platforms to hold a camera. See Professional Aerial Photographers Association, The History of Aerial Photography. The earliest known surviving aerial photograph was taken by James W. Black using a tethered hot air balloon over Boston in 1860, while the first known free flight of an aerial camera was by balloon over Paris in 1879. Almost 50 years later, in 1907, German apothecary Julius Neubronner starting fitting pigeons with an aluminum breast harness and camera and eventually sold images as postcards at the Frankfurt International Aviation Exhibition and at the 1910 and 1911 Paris Air Shows. Aerial photography has captured scenes of immense historical importance such as George Lawrence’s “San Francisco in Ruins” taken with a 49 pound camera flown by a train of kites 2,000 feet above the city after the devastating 1906 earthquake. The image he captured was a mammoth 18 x 48 inches in dimension.

The analysis of aerial photography as a systematic method for gathering information began in earnest with World War I, when as many as 10,000 frames of aerial photography of enemy lines and potential bombing targets were taken and printed in a day for aerial photography interpreters to analyze. It was also during this time the first airplane-specific mapping cameras were developed. The routine use of aerial photography for natural resource application began in this country in the 1930s, growing out of the need to assist farmers after the dust bowl and concurrent great depression, where government aerial photo interpreters and soils scientists used aerial photography to assess the effects of the dust bowl. After the second World Ward war, aerial photography interpretation continued to play an important role where civilian agencies such as the U.S. Geological Survey (USGS) and the U.S. Department of Agriculture (USDA) routinely flew aerial photography missions for agency-specific purposes, creating detailed topographic maps and soil surveys respectively. Fortunately, much of the vast historical archive of aerial photography is held by government institutions and has been preserved for our backward-looking research needs.

Reliable Principles and Methods

Aerial photography interpretation has had a long history of reliably producing intelligence for military purposes and the basis of making maps for civilian use. I still employ the tools and standard methods for my field that were used historically, a light table using overlapping photographic prints or transparencies and an optical stereoscope, but have also incorporated onscreen viewing and analysis using GIS software. Viewing overlapping frames of aerial photography, known as stereo viewing, enables me to see the heights of objects or terrain and determine slope of the land and direction of surface flow. Whichever way it is done, viewing the aerial photography at various magnification levels allows me to zoom in on a site for detailed examination of site-specific features and conditions, while viewing the site from a distance allows the observation of the site in its landscape context and in relationship to other features of interest.

The analysis of historical aerial photography reveals the natural and cultural conditions at the time the photo was taken. The analysis of a chronological sequence of aerial photography reveals consistent conditions and features over time, as well as changes to them. For example, I have observed wetland areas on aerial photography from the 1930s and 1940s to determine their historical conditions. By then examining more recent aerial photography I have described changes to the wetlands over time.

Objects, features or conditions seen on aerial photography can be recognized by their unique signatures. An aerial photography signature is the combination of shape, size, pattern, photographic texture, tone or color, along with the association with other objects, features or conditions that allow for its identification. For example, wetlands can be identified from aerial photography by their association with depressional or low gradient drainage areas, flood plains, by their adjacency to lakes, estuaries or other water features, the texture and pattern of their characteristic vegetation cover (emergent, shrub or forested vegetation) and their photographic tone caused by standing water, wetland drainage patterns, and persistent ground moisture conditions.

Today, GIS facilitates the analysis of aerial photography data and geospatial sets. GIS allows for the accurate overlay of multiple dates of aerial photography (which are geo-referenced to a common map projection) for easy change detection. Sequential aerial photography covering an area of interest can be rapidly turned on and off with a click of the mouse creating a dynamic visual picture of change of an area over time. GIS can be used to overlay and compare features or conditions seen on aerial photography to collateral geospatial information such as USGS stream and elevation data, National Wetland Inventory (NWI) data, soil survey data, as well as other investigative reports and data that cover the area of interest. Collateral data is used to add information not obtainable from aerial photography alone, such as stream names or flow characteristics. This data is also used to offer a second opinion to support, or provide evidence to refute, the identification features and conditions seen on the aerial photography. For example, stream reaches and wetland boundaries observed on aerial photography can be compared to USGS stream flow paths and NWI wetland boundaries to see if there is a convergence of evidence and options to support the analysis, or not.

The large suite of tools found in GIS software can be used to measure area, length, and even the height of features seen on the aerial photography. For example, the size of historical wetlands and their reduction in size due to manmade encroachment can be measured using the GIS tools. GIS tools can be used to create, edit, clip, and combine data sets. GIS can be used to clip large data sets to a smaller study area for ease in handing and to combine data sets for further analysis. Finally, the mapmaking functions contained in GIS software can be used to create scaled thematic maps with annotations, north arrows, and legends for use in reports, displays, and trial exhibits.

Relevant to the Task at Hand

Burnt Fly Bog Superfund site located in Marlboro Township, New Jersey, is named after a large wetland area that took the brunt of the pollution that was released from the site when large lagoons containing waste oil leaked, and one eventually ruptured, pouring a toxic sludge into the nearby Burnt Fly Bog. In 1983 the area was designated a Superfund site and by 1993 the cleanup of the lagoons was complete. See EPA Region 2, NPL Listing History. In 1997 the Department of Justice (DOJ) initiated a cost recovery action against the defendants. Using some of the aerial photography interpretation methods described in this report, I conducted an analysis of historical aerial photography, maps, and other data to support the DOJ investigation. The analysis of the historical aerial photography revealed that the major breach of the lagoon, which lead to a massive plume of oil laden water, occurred between 1963 and 1967. From the analysis of the aerial photography, I could see the breach, the underlying topography, flow patterns, and the large plume. I was called to testify and presented my findings in court in 2003. U.S. & New Jersey v. Dominick Manzo, Carmella Manzo & Ace-Manzo, Inc., Civil Action No. 3:97-cv-00289.

The “before and after” aerial photography dramatically showed the results of the lagoon breach in the 1960s. Pinning down a time frame (in this case between 1963 and 1967) when spills or other waste disposal activity is visible in the historical aerial photography record helps CERCLA enforcement officials determine who was responsible.

Partially based on the aerial photography record, as well as other records, a judgment was awarded in favor of the United States for $31 million in costs incurred cleaning up the Burnt Fly Bog Superfund site. DOJ Summary of Litigation Accomplishments 2006.

In a CWA case, United States v. Lucas, 516 F.3d 316 (5th Cir. 2008), a Mississippi developer was charged with filling of federally protected wetlands without a permit and other related crimes. In CWA enforcement, the government must prove five basic elements; that 1) a person (or company), 2) discharged a pollutant, 3) via a point source, 4) into a water of the United States, and 5) without a permit. Aerial photography interpretation can be instrumental in demonstrating a discharge occurred, that it was from a point source, and that the discharge was into a water of the United States. To demonstrate the latter, the United States was required to show that the wetlands where the pollutant was placed (in this case earthen fill was the pollutant) were part of the surface water tributary system that leads to the Gulf of Mexico. This was a perfect fit for aerial photo interpretation and mapping. Interpreting multiple dates of aerial photography in the GIS environment (on screen), I interpreted wetland and drainage path signatures, mapped their locations, and compared this to collateral information such as the NWI, soil maps, and USGS stream and elevation data. I mapped the flow paths and overall surface water connection as they went to the Gulf of Mexico. One aspect of the aerial photography interpretation vital to the case was the creation of more detailed stream maps than were available from the USGS. Using the details seen in the sequential aerial photography, I was able to see and map streams and drainage patterns not previously identified by the USGS. This detailed stream mapping, which showed a dense network of tributaries (and adjacent wetlands), was instrumental for the government to prove that the discharge of pollutants was into the surface water tributary system to the Gulf of Mexico.

I testified in the case as an expert witness, over the objections of the defendants. See Defendants’ Memorandum In Support of Motion to Exclude Testimony, Opinions, and Powerpoint Presentation of Peter M. Stokely, United States v. Lucas, Criminal No: 1:04cr60GuRo (U.S. S.D. Miss. Jan. 25, 2005). Using the courtroom’s audio-visual capabilities and the GIS zooming tools, I was able to show the jury the clearly visible signatures of the streams and wetlands as seen on the aerial photography. Based on the live GIS presentation, and other facts placed in front of the jury, Robert Lucas was sentenced to nine years in prison for violating the CWA by filling in wetlands without a federal permit, and for conspiracy and mail fraud for selling homes to hundreds of families despite the warnings from public health officials that the illegal septic systems were installed in saturated soil and were likely to fail causing contamination of the underlying property and the drinking water aquifer. Lucas’s codefendants were each sentenced to serve eighty-seven months in prison, and his two companies were ordered to pay a total $5.3 million in criminal fines. DOJ Summary of Litigation Accomplishments 2006.

Not surprisingly, with such a stiff sentence, the Lucas defense team appealed the verdict, which was upheld. United States v. Lucas, 516 F.3d 316 (5th Cir. 2008). GIS and aerial photography interpretation were front and center in the appeals court ruling. In affirming the sufficiency of the evidence supporting the finding that the wetlands fell with the coverage of the CWA, the court relied on the testimony and mapping evidence that was based on aerial photography interpretation and mapping:

The Government maps of Big Hill Acres presented at trial also show Fort Bayou Creek, Bayou Costophia, tributaries to Bayou Catophia, and tributaries to Little Bluff Creek all connected to the development property, and all eventually flowing into the navigable Tchoutachabouffa River, the Pascagoula River, and the Mississippi Sound. Expert Peter Stokely testified that “there is a continuous band of wetlands and streams and creeks that lead from the site to the waters,” and showed aerial photographs of “drainage and wetlands patterns on the site” as well as drainage and wetlands patterns that “branch up towards the site” and that lead “up on to the property itself.”

Id. at 326–327.

In Lucas, the factors supporting federal CWA jurisdiction were rather straightforward: were the wetlands connected by a surface water tributary to the Gulf of Mexico? Since Lucas, the inquiry into whether wetlands and streams are jurisdictional under the CWA has been complicated by Rapanos v. United States, 547 U.S. 715 (2006). While a complete discussion of jurisdiction after Rapanos is beyond the scope of this article, a couple of concluding points regarding use of aerial photography and maps to determine federal CWA jurisdiction after Rapanos are worth making. Establishing CWA jurisdiction has long required the examination of certain geospatial relationships that can be revealed from aerial photography and maps; tributary connections and wetland adjacency. However, Rapanos has added some additional lines of inquiry regarding whether waters are jurisdictional: their relative permanence and a significant nexus to traditional navigable waters. These new standards also contain elements of inquiry that can be explored directly with geospatial data.

The post-Rapanos standards were addressed head on in the case of Smith Farms, located in Chesapeake, Virginia. The case was first heard by an EPA administrative law judge in 2005 where I presented my aerial photography interpretation regarding the presence of wetland, the placement of fill material in them and other facts relevant to the case. After Rapanos, the case was remanded back to the EPA administrative law judge for further fact finding regarding the standards for CWA jurisdiction consistent with Rapanos. In a May 2007 hearing, I addressed the CWA jurisdiction issue by presenting additional facts based on aerial photography, such as the historic presence of wetland and streams, the proximity of the wetlands to tidal waters and the acreage and locations of similar wetland in the area. On the post-remand, the EPA ALJ again found federal jurisdiction, stating “[i]t is important to take note that the numerous photos which were included within [exhibit] show, through historical aerial photography, that several of the drainages at the Site have been in existence for a very long time” and “[t]hus, it is fair to note that the USGS has identified these as relatively permanent geographic features for decades. In re Smith Farm Enterprises, LLC, 2008 WL 13741 (E.P.A. Mar. 07, 2008) (No. CWA-03-2001-0022). The ALJ decision was affirmed by the EPA Environmental Appeals Board. Final Decision and Order, In re Smith Farm Enterprises, 15 E.A.B. ____ (Mar 16, 2011), which noted that the “aerial photographs and maps depict the conveyance of water via these tributaries to navigable-in-fact waters over time, and from as early as 1920, document a quantity and regularity of flow that cannot be said to have been “remote,” “irregular,” insignificant or “minor” as reflected by Justice Kennedy.” Id. at note 31. An appeal is pending in the Fourth Circuit Court of Appeals.

The judge in Smith, the jury and appeals court in Lucas, and the court in Burnt Fly Bog found the analysis of historical aerial photography and mapping using GIS to be based on a “reliable foundation” using “reliable principles and methods” and that it was “relevant to the task at hand” of demonstrating the factors relevant to enforcing our environmental laws. While eyewitness accounts, corporate records, surveillance, and database searches will always important when developing an environmental enforcement case, aerial photography and mapping, particularly historical aerial photography and maps, can be also key pieces to the environmental enforcement puzzle.

Peter Stokely

Mr. Stokely is an environmental scientist in EPA’s Office of Civil Enforcement, Washington, DC.