GIS for Water Resources and Watershed Management - Chapter 18 pptx

Thus,the historical aerial photograph, unlike many newer and more sophisticated sensors, is an inexpen-sive source of invaluable information which can be used to locate a waste disposal

limita-Airborne radars can penetrate sand in hyperarid environments, between 1–6 meters in depth(Sabins, 1987); penetration is minimal in humid soil areas Thermal sensors can display tempera-ture variations at the surface, sometimes suggestive of subsurface conditions and multispectral andhyperspectral scanners can detect subtle changes in the surface environment which may be sug-gestive of buried features The historical aerial photograph, however, frequently has resolutionsfor detecting barrel size or smaller features, and the ability to show site conditions long ago Thus,the historical aerial photograph, unlike many newer and more sophisticated sensors, is an inexpen-sive source of invaluable information which can be used to locate a waste disposal site and meas-ure accurately the size and dimensions of currently buried or overgrown features and to generallytrack the history of waste disposal site activity from beginning to end.

THE HISTORICAL AERIAL PHOTOGRAPH

The historical aerial photograph is the sensor of choice of the Environmental ProtectionAgency’s Environmental Photographic Interpretation Center (EPIC), which for the past 25 plusyears has been applying this tool for locating potential waste disposal sites and characterizingthese sites and associated waste disposal practices The historical aerial photograph is an ex-tremely powerful remote sensing tool It is the only remotely sensed data to have recorded events

at sites frequently as far back in time as the 1930s This is of immense value to the Superfund gram which is charged with looking for and evaluating abandoned hazardous waste disposal sites,sites which today may display no evidence at the surface of their former use (Slonecker et al.,1999) The tool is of substantial value in litigation as evidence of the past waste disposal practices

pro-of PRPs (Principal Responsible Parties), and has been highly successful at assisting EPA and partment of Justice lawyers in winning their cases In addition, the ability to view the aerial photostereoscopically (in 3-D) and to measure, using photogrammetry, the heights, depths, volumes,and other dimensions of features and materials currently present, long removed from, or buried at

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a site has also contributed invaluable evidence in courtroom situations, and has helped to struct pictorially for jurors and judges alike and in an easily understandable format, the activity at

recon-a site over time Finrecon-ally, the recon-avrecon-ailrecon-ability of historicrecon-al recon-aerirecon-al photogrrecon-aphs from both government recon-andprivate sources, and the extent of aerial photo coverage of the United States, through various fed-eral agency mapping programs such the Agricultural Stabilization and Conservation Service (nowFarm Services Agency), and the U.S Geological Survey, to name only two, have literally ensuredthat a hazardous waste disposal site located within the conterminous US has been overflown andsite conditions documented more than once during the site’s disposal history

This chapter focuses on the value of the historical aerial photograph and the various imageanalysis and mapping functions which use aerial photos for analyzing hazardous waste disposalsites

THE BASICS OF AERIAL PHOTOINTERPRETATION FOR

WASTE SITE CHARACTERIZATION

Backlighting and Variable Magnification

Using backlighted tables with adjustable illumination, and high-power magnification zoomstereoscopes, aerial photographs are interpreted for site size, drainage patterns, type of fill materi-als, leachate, burial sites, lagoons, impoundments and their contents, and general condition of thesite Locations and descriptions of tanks, drums, open storage areas, evidence of vegetation stress,on-site obstacles, structures, equipment, access routes, and other details may also be obtainedthrough photo analysis Historical analysis provides the information necessary to obtain a chrono-logical understanding of a site’s development and activities This information is particularly im-portant for describing and illustrating past activities and conditions at abandoned hazardous wastedisposal sites which fall under the jurisdiction of the Comprehensive Environmental Response,Compensation, and Liability Act (aka Superfund) program

Film Transparencies

The use of aerial photo transparencies on backlighted variable illumination tables maximizesthe available information content of analyzed aerial photographs Aerial photo transparencies arefirst generation copies of originally exposed film Each additional step of film processing, such asproducing additional film copies or photographic prints degrades from the original product and re-duces the amount of information contained in the original photo High-powered magnifyingscopes are used to identify subtle, but often significant features on aerial photos which can easily

be overlooked if not viewed with the benefit of backlighting and variable magnification

Stereoscopy

The importance of stereoscopy in the photointerpretation process cannot be ignored oscopy allows the photo analyst to see features on an aerial photograph in three dimensions (3-D).Through stereoscopic parallax (the apparent displacement of the position of a feature in an imagecaused by a change in the position of observation) a stereoscope may be used to view overlapping

When coupled with various measuring devices such as stereo comparators or other digital togrammetric devices highly accurate measurements can be made of the dimensions (height,widths, lengths, depth) of features seen on the aerial photograph Volumes of materials and volu-

pho-Figure 18.1 Acquisition of stereoscopic aerial photographs and stereoscopic parallax The area of 60% ward overlap is shown as the cross-hatched area, and it represents the same ground area photographed along a flightline by two overlapping aerial photos.

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metric capacities of excavations can be calculated This same technique is used to make graphic maps which show land surface elevations using contour lines.

topo-The Signature Concept

A basic part of photointerpretation is the extraction of useful information from an image though this may be performed by human (manually) or machine (electronically by computer) de-pending on the form of the original data (e.g., as analog, hard copy photos versus digital images,respectively) the photo analysis performed by EPIC in support of EPA’s hazardous waste program

Al-is conducted almost exclusively by manual, not machine analysAl-is Using manual methods, sometypes of information displayed on aerial photos are obvious to anyone used to reading a map Anexample includes large bodies of water However, the vast bulk of information is not evident to theuntrained or inexperienced viewer

The training and experience that makes feature identification possible on aerial photos is based

on learning to recognize combinations of imagery characteristics called signatures A signature is

a combination of visible characteristics (such as color, tone, shadow, texture, size, shape, pattern,and association) which permit a specific object or condition to be recognized on an aerial photo-graph The relative potential of a given signature to enable possible, probable, or positive identifi-

cation of an object or condition is the degree of certainty Possible is a term signifying a degree of

certainty of signature identification when only a few characteristics are discernible on a photo or

these characteristics are not unique to a signature Probable, on the other hand, is a term

signify-ing a degree of certainty of signature identification when most characteristics, or strong or uniquecharacteristics of a signature are discernible but fall short of positive identification

When interpreting an aerial photograph, the analyst is generally searching for the signature ofone or more objects or conditions by viewing aerial photo stereopairs through stereoscopes An an-alyst relies either on experience or “ground truth” information (corroborative information obtainedthrough other data sources or on-site field visits to the site) in identifying signatures When work-ing with historical aerial photographs of areas that have changed or are inaccessible, experiencebecomes critically important For some forms of photo-interpretation, e.g., to map wetlands vege-tation or forest types, signatures representative of various vegetation types are confirmed by on-site visits and then extrapolated over a much larger area to map vegetation types displaying thesame signatures, but not visited on the ground

The signature concept is not an all or none concept since signatures can vary in degree of

cer-tainty Because of this it is essential to clearly distinguish between positive identifications andcalls of lesser certainty Because hazardous waste site characterization by aerial photo interpreta-tion may be used to support civil or criminal litigation, it is important that the degrees of certainty

be clearly stated by the photo interpreter

The characteristic signature of a given object or condition can vary with the type of film or agery, scale, resolution, and other factors Therefore, aerial photos vary in suitability depending onthe object of the analysis For example, 55-gallon drums can be positively identified on averagequality, 1:6,000 scale aerial photographs On the other hand, typical 1:20,000 scale aerial photos

im-do not normally allow for positive identification of drums, but may allow for possible or probable

identifications to be made Even smaller scale (higher altitude) imagery is so inappropriate for

drum identification that even possible identifications cannot be made Variability in photo type

also affects the interpretability and signatures of objects Natural color, color infrared, and blackand white aerial photos, for example, have no sensitivity for heat detection, while thermal scannerimagery can reveal temperature differences of objects An experienced photo interpreter is able to

use a variety of remote sensing tools and is fully knowledgeable of the capabilities and limitations

of these tools for specific applications Table 18.1 is a listing of the kinds of features, natural sources, and site activities which are routinely identified on aerial photographs by skilled imageanalysts for characterizing waste disposal sites.

re-OVERVIEW

Hazardous Waste Site Analyses

Hazardous waste disposal site characterization using historical and current aerial photographscomprises a major part of EPIC’s workload Utilizing the vast archives of aerial photographs ofthe country maintained by government and private sources, dating back to the 1930s, EPIC’s ana-lysts reconstruct the waste handling and disposal history of a site in order to support site cleanupand regulatory or enforcement efforts Aerial photographs have proved to be powerful tools incourt in the form of evidence and to support expert witness testimony and for facilitating the re-covery of millions of dollars in site cleanup costs and penalties from responsible parties (Garofaloand Wobber, 1974; Erb et al., 1981; Evans and Mata, 1984; Stohr et al., 1987; Mata and Christie,1991)

The information interpreted from an aerial photograph is annotated onto a clear film overlaywhich identifies and delineates the location of significant ground features and activities Accom-

Table 18.1 Hazardous Waste Disposal Site Features/Activities Routinely Extracted by Image Analysis from Historical Aerial Photographs

Flow direction Graded area Ground scar Historical boundary Horizontal tank Impoundment Indeterminate drainage Lagoon

Landfill Leachate Light-toned Liquid Material Medium-toned Mounded material (extensive) Mounded material (small) Objects

Open storage Outfall Pipeline Pit Pond Possible drum area

Pressure tank Probably underground drainage Railroad

Refuse Revegetated Revetment Site boundary Sludge Solid waste Stacked objects Stain

Standing liquid Structure Study area Surface runoff Suspected drainage Tank farm

Tank trailer Trench Unfenced site boundary Vegetated

Vegetation stress Vehicle

Vehicle access Vertical tank Waste disposal area Wastewater treatment plant Wetland

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Figure 18.2 Sample historical site analysis prepared by EPIC October 19, 1958 No significant activity was evident on the 1946 or 1947 photographs (not shown here) Significant features observed on the 1951 photographs are annotated and discussed in conjunction with the following analysis

The landfill study area consists of two landfills, the Western Landfill and the Eastern Landfill Both fills are south of Wheatfield Road No significant activity is visible within the portion of the study area north

land-of Wheatfield Road throughout the analysis, and this area will not be discussed further.

Each landfill is divided into three portions for the purpose of discussion The northern, central, and ern portions will not be annotated further Fill areas are annotated in both landfills throughout the analysis, but are not discussed individually Disposal activities noted within fill areas are annotated and discussed Drainage at and around the landfill is shown in the Wetland and Drainage analysis ( Figure 18.10 ) Min- imal changes were evident in the overall drainage routes throughout the years of analysis Minor variations

south-in drasouth-inage resulted from the gradual development of the landfill These transient drasouth-inage routes are tated for each year of analysis, but are not discussed unless a significant change is visible.

anno-Western Landfill No significant activity is evident.

Eastern Landfill Northern portion In 1951, possible refuse (R) was noted in a possible fill area (FA) outside the eastern site boundary.

In 1958 the east side has been partially cleared (not annotated) Material (M) is piled in three areas within the clearing A possible excavation (EX) with dark-tone (DK) liquid (LQ) is noted on the south edge

of the clearing Possible refuse remains evident in the possible fill area outside the eastern site boundary Central and southern portions No significant activity is evident.

Figure 18.3 June 17, 1964 Western Landfill No significant activity is evident.

Eastern Landfill Extensive clearing (not annotated) is underway in the eastern landfill, and brush piles (not annotated) are scattered throughout the clearing.

Northern portion The material and possible excavation with liquid seen in 1958 are no longer visible Piles of coarse-textured (CT) material, an open storage (OS) area, a building (B) with a parking area, and

an empty excavation, possible a catchment basin, are noted in the northern portion of the landfill A variety

of objects and equipment are visible in the open storage area The open storage area, building and parking area remain active and expand throughout the analysis, and will be annotated but not discussed in detail The possible refuse seen outside the eastern site boundary in 1958 is no longer visible.

Central Portion Piles of coarse-textured material and a rectangular bermed area are visible The bermed area appears empty, and its use is not evident.

Southern Portion An impoundment (IM1) and an excavation are visible IM1, a leachate collection poundment, is dry inside and contains a small amount of material The excavation contains murky liquid.

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Figure 18.4 April 17, 1968 Western Landfill North portion A wetland has been cleared (CL); however, there is no evidence of fill activity in this location.

Central Portion Extensive filling has occurred since 1964, an impoundment (IM2), an excavation, ing (GR), and material are evident A channel leads from the east edge of the landfill into IM2 Murky liq- uid is visible in the channel and in IM2 The excavation is on the southwest side and appears to be empty Southern portion No significant activity is evident.

grad-Eastern Landfill Northern portion The coarse-textured material noted in 1964 is no longer present A berm and the grading of a fill area are evident in the northern portion The graded fill area includes the former excavation which was noted in 1964.

Central portion The bermed area and debris (DB) are visible The bermed area remains empty, and the debris is along the edge of a fill area.

Southern portion IM1, debris, two pits, and two excavations are visible IM1 contains liquid, the debris

is along the edge and sides of a fill area, the northern pit is full of dark-toned liquid, and the southern pit contains a small amount of dark-toned liquid/material Both excavations contain murky liquid.

A drainage channel is visible at the south edge of the site It receives runoff from slopes south and east

of the landfill as well as from on-site The channel leads west to the natural drainage, which flows north ( Figure 18.10 ).

Figure 18.5 July 18, 1971 Western Landfill North portion Vegetation (VEG) is growing where the clearing

of a wetland was noted in 1968.

Central Portion Filling has continued since 1968, and the upper surface of the landfill has been graded IM2 contains dark-toned liquid Dark-toned liquid is adjacent to the east side of IM2, indicating the possi- bility of a breach or overflow in the impoundment The western excavation is no longer visible A dark-toned stain (ST) extends from the top of the landfill downslope to the base, as if caused by a liquid

Southern portion Extensive filling has occurred since 1968 A clearing is noted along the southeast edge Eastern Landfill Northern portion The fill area with a berm noted in 1968 is vegetation A shallow exca- vation is noted south of the former fill area The graded fill area noted in 1968 and part of the parking area around the building are in use for open storage A large clearing is seen on the west side of the landfill Central Portion Vegetation is growing where a fill area with debris was noted in 1968 The bermed area appears inactive and is partially overgrown with vegetation A clearing is seen on the west side of the landfill Southern portion The northern pit seen in 1968 is no longer present; the southern pit is smaller and ap- pears empty IM1 contains liquid The debris seen along the edge of a fill area in 1968 is no longer visible, and the top of the fill area has been graded A small amount of probable debris is evident on top of the fill area The two excavations remain and contain murky liquid.

Tree canopy obscures the drainage channel seen along the south edge of the landfill in 1968.

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panying text provides a full site description Figures 18.2 through 18.11 illustrate a standard torical site analysis of a hazardous waste disposal site, and show the kinds of information that can

his-be extracted from an analysis of these photos, and changes at the site over time The historicalanalysis clearly shows and documents the location of major fill areas which were evident duringthe life of the landfill Disposal-related activities identified within the fill areas include debris, ma-terial, refuse, dark-toned liquid in erosion rills, excavations, and pits containing liquid Between

1964 and 1984 a leachate collection impoundment was present on the site and a second leachatecollection impoundment was present from 1968 through 1984 An upgraded leachate collectionimpoundment was present from 1980 through 1992

Inventories of Potential Hazardous Waste Sites

Inventories of potential hazardous waste sites covering large areas and decades in time are avery cost-effective way to discover sites for future investigation The aerial photographs are sys-tematically searched for specific features or to identify types of sites Type might include landfills,open dumps, scrap salvage yards, chemical handling and storage facilities, impoundments, orabandoned industrial sites Identified sites are located on overlays to topographic maps accompa-nied by data sheets describing site conditions The site conditions are presented chronologicallywith the period of site activity shown on the map overlay This approach is helpful to determinethe origin of a progressive problem and to identify a hazardous site that is currently hidden by newdevelopment

Emergency Response

EPIC reacts through quick response capabilities to emergency situations such as hazardous rial releases and natural disasters like hurricanes (Hugo) and earthquakes (San Francisco/Oakland,CA) Aerial photographs are flown, processed and analyzed to provide immediate information to on-site personnel regarding circumstances not easily or safely observed from the ground Typical prod-ucts for an emergency response include an immediate telephone report to on-site personnel followed

mate-by photographs or positive film transparencies with interpretation results annotated on overlays, notated topographic maps, and a short letter report describing analysis results

an-Wetlands

Wetlands analyses are performed by EPIC in support of various sections of the Clean Water Actconcerning enforcement, permitting, and advance identification Analysis of historical aerial pho-tographs is often the only means of establishing the prior existence of wetlands on lands that havebeen dredged or filled, and for calculating wetlands loss acreage necessary for mitigation settle-ments Aerial photographs also provide information concerning vegetative type, periodicity offlooding, tidal influences, and affected drainage patterns

EPIC image analysts perform various types of wetlands mapping depending on the needs of the

requesting EPA headquarters or regional program office A wetlands/upland boundary delineation

identify the location of wetlands and to separate wetlands from nonwetlands areas A detailed

lands analysis is performed to identify and classify various wetland types, often using the

wet-lands and deepwater habitat classification developed for the Fish and Wildlife Service by

Cowardin et al (1979) Using jurisdictional wetlands delineation procedures and associated

field-work, EPIC maps wetlands in support of Section 404 of the Clean Water Act which protects

wet-lands from unpermitted dredge and fill activities Also, in support of the Advance Identification

process of Section 404, wetlands maps are prepared as a cost-effective way to identify wetlands inadvance of permit application and evaluation EPIC also performs image interpretation for wet-lands delineation in support of EPA enforcement cases Historical aerial photographs are usedalong with field checking to map wetlands losses and change due to filling and/or dredging activ-ities Photogrammetry is used to make accurate quantitative measurements of wetlands losses, ex-tent of filling, and overall area changes Geographic Information Systems (GIS) technology isapplied to produce maps and graphics displays which are suitable for courtroom presentations andwhich clearly illustrate these changes

Photogeology

EPIC employs aerial photointerpretation to study the geology of an area from an analysis oflandforms, drainage, tones/textures, and vegetation distribution EPIC conducts two types of pho-togeologic analysis and mapping: fracture trace and lithologic

Fracture trace analysis involves the use of aerial photographs and other types of remote

sens-ing imagery to identify linear features on the earth’s surface that are naturally occurrsens-ing and are

in cross-section, fracture traces are seen to be vertical or near vertical breaks in the bedrock tures are of particular environmental concern because contaminants are likely to move more easilythrough zones of fractured bedrock than through the surrounding more consolidated bedrock ma-terial Thus, fracture traces can be used to identify possible migration routes of pollutants and areoften used in the placement of monitoring/remedial wells around hazardous waste sites (Stohr etal., 1987; Scheinfeld et al., 1988; Mata and Christie, 1991)

Frac-EPIC conducts lithologic mapping (mapping of distinct rock types or units) from aerial

photo-graphs in order to produce a more accurate geologic map in areas where geologic mapping is complete due to limited fieldwork, small map scale, or other factors (Figure 18.9B) Thisprocedure is usually performed by consulting available geologic maps of the area

in-Photogrammetric Mapping

In support of EPA’s mission, EPIC produces highly accurate topographic and planimetric maps,generally at a large scale, which conform with National Map Accuracy Standards and EPA Pho-togrammetric Mapping Specifications Map scales, contour intervals, and planimetric details can

be varied to suit specific requirements

EPIC uses analytical stereoplotters, digital video plotters, or other digital photogrammetricmethods to measure the area and volume of hazardous wastes; determine the height and placement

pits Changes in size, shape, and other physical characteristics of a waste site are documentedthrough sequential photogrammetric mapping (Slima, 1980)

Photogrammetric techniques are also used by EPIC to establish precise location and orientationdata to support geophysical monitoring or for monitoring well placement

Geographic Information Systems (GIS)

EPIC applies GIS technology to support a variety of EPA Headquarters or Regional ProgramOffice Needs For example, a National Priorities List (NPL) hazardous waste site investigationwas performed using information from diverse sources (including numerous years of historical

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