Archaeological Geophysics Survey of Atlanta's Gulch

275Archaeological Geophysics Survey of Atlanta’s Gulch Patch and Lowry

ARCHAEOLOGICAL GEOPHYSICS SURVEY OF ATLANTA’S GULCH

by Shawn M. Patch (New South Associates, Inc.) and Sarah Lowry (New South Associates, Inc.)

Supplemental material for this article is available:http://thesga.org/category/publications/early-georgia-publications/supplementary-material/

INTRODUCTION The Georgia Multimodal Passenger Termi-

nal (MMPT) will bring together various bus and rail transit services in downtown Atlanta, Fulton County, Georgia (Figures 1-2). This project re-quires compliance with Section 106 National His-toric Preservation Act (NHPA) of 1966 to identify potential archaeological resources that may be ad-versely affected by the proposed undertaking. The archaeological study area was approximately 25 acres in size and characterized by a series of sur-face parking lots and an elevated parking garage. Identification efforts included extensive archival research, historic map review, soil coring to assess depositional contexts, in-field artifact analysis, and geophysical survey (Patch et al. 2013). This paper focuses on the methods and results of the geophysi-cal survey, which formed a major component of the archaeological assessment. The present study is unique because of its large scale, urban setting, and archaeological resource types. We demonstrate the use of geophysical data to 1) identify archaeological features, 2) address broad research themes and de-rive archaeological interpretations, 3) assess physi-cal integrity of subsurface deposits, and 4) generate primary data for site evaluation for the National Register of Historic Places (NRHP).

The Gulch has been closely associated with railroads and transportation since the found-ing of Atlanta (Alexander 1970; Crimmins 1982; Garrett 1969a, 1969b, 1987; Patch et al. 2013).

During its early years its topography was character-ized by a deep ravine surrounded by rolling hills, springs, and old-growth forest. Three converging railroads were established in the 1850s and formed a distinctive wye pattern that is still visible today. By the early 1860s the rail network had grown to include large masonry structures such as a large roundhouse and turntable. For these reasons, the Gulch was a major target during the Civil War and most of these were destroyed. The transportation infrastructure was rebuilt quickly and the area saw rapid growth and development through the late 1800s, including filling and leveling of the ravine. In the early 1900s Atlanta Terminal Station was established and the Gulch became a major passen-ger hub that lasted until mid-century. Eventually, the freight operations of many railroads passing through the Gulch were transferred to other rail yards and passenger rail travel was largely discon-tinued. The passenger terminals were demolished, the majority of tracks were replaced with parking lots, and the industrial and municipal structures that paralleled the tracks were abandoned or re-placed by modern office complexes and entertain-ment venues. The physical imprint of the transpor-tation network is still present today.

Current trends in geophysical archaeol-ogy are moving toward expanding the interpre-tive value of geophysical data to explicitly address anthropological questions (Conyers and Osburn 2006; Conyers and Leckebusch 2010; Conyers

276 Early Georgia volume 41, number 2

Figure 1. Study area in Fulton County, Georgia.


Figure 2. Detail of study area.


2012; Kvamme 2003). There is a growing recogni-tion among practitioners that geophysical data can provide unique and highly detailed perspectives on archaeological sites that goes beyond simply iden-tifying subsurface features (although that remains important). This may be particularly applicable to larger sites and/or cultural landscapes where tra-ditional methods might provide only a small win-dow on broader patterns. Kvamme et al. (2006:9) wrote: “remote sensing alone can yield primary data suitable for the study of cultural forms within archaeological sites and landscapes.” Technologi-cal advances in recent years have demonstrated the effectiveness of various equipment and methods (Aspinall et al. 2009; Bevan 1998; Conyers 2004; Ernenwein and Hargrave 2009; Gaffney and Gater 2003).

METHODS Because of the study area’s urban setting

and the presence of surface parking lots, existing rail lines, fences, utility poles, buildings, and other obstacles, traditional archaeological survey was not considered a viable option for site identification. However, the area was well suited for geophysical survey because of the surface conditions and ex-pected feature types (Bevan 2006). Geophysical methods are generally fast, efficient, reliable, ac-curate, and, most importantly, non-invasive. They provide an alternative way of viewing and under-standing archaeological sites and in certain cases may be the only means of generating important information.

Detection of buried features and objects with all geophysical instruments is based on the presence of contrasts (Kvamme et al. 2006:8). Basi-cally, the objects of interest must be different from the surrounding matrix. Contrasts can take a va-riety of forms, including differences in chemical, electrical and magnetic properties, or materials (e.g., concrete versus sandy loam). Not surpris-ingly, greater contrast generally equates to better detection.

Planning the geophysical survey of the Gulch required consideration of a number of lo-

gistical factors that affected instrument selection (Ernenwein and Hargrave 2009). Under certain conditions multiple instruments are sometimes preferable because they are designed for different purposes and may provide more comprehensive resolution (Clay 2001; Ernenwein and Hargrave 2009; Kvamme et al. 2006). However, in most prac-tical applications there are limitations that will af-fect instrument selection and, as Bevan (2006:29) pointed out, if a particular geophysical instrument is known to work well for detecting the features of interest, that may be sufficient. Consideration was given to the four geophysical methods commonly used in archaeology: GPR, magnetometry, electri-cal resistance, and electromagnetic induction.

Magnetometry and electromagnetic in-duction (EM) were not used primarily because of known interferences from existing rail lines, chain link fences, metal utility poles, parked cars, and the possibility of rebar in concrete (Aspinall et al. 2009; Bevan 2006:29; Silliman et al. 2000:106). Because of the strength of these sources in rela-tion to instrument sensitivity, they tend to obscure more subtle features, although under certain cir-cumstances good data can still be collected (Cook and Burks 2011). Electrical resistance was not used because the paved surfaces were a physical barrier to data collection. GPR was selected as the most appropriate instrument given the urban setting, known sources of interference, depositional and stratigraphic complexity, and expected feature types and depths, Ultimately, the decisions for in-strument selection were made in consultation with GDOT’s staff archaeologist and balanced with schedule demands, funding constraints, property access, and, most importantly, information return.

Prior to fieldwork, the study area was di-vided into contiguous 30-meter grids using ArcGIS mapping software, aerial imagery, and existing in-frastructure information (Figure 3). Each 30-meter grid was given a unique identifier consisting of a letter and a number (e.g., A1, F12, etc) and all grid corners with corresponding UTM coordinates. Grid corner point identifiers were exported to both a Trimble GeoXT global positioning system (GPS) and a TDS Recon total station data collec-


Figure 3. The project area was divided using a 30-meter grid.


phones and radio towers. Finally, hyperbola fitting was used to estimate the velocity of radar energy and approximate the RDP throughout the profile. The geometry of the hyperbolas is dependent on the velocity; hyperbola shape is quantifiable and can be used to generate the velocity (Conyers and Lucius 1996). Multiple values were recorded for each grid at varying depths in the profile and then tracked on a spreadsheet.

Individual RDP values varied considerably both horizontally and vertically across the study area but were all in the normal range for GPR data in typical settings (see Patch et al. 2013 for extensive discussion). Briefly, average RDP values were calcu-lated for the entire sample (8.71), 0-5 nanoseconds (6.54), 5-10 nanoseconds (8.42), 10-15 nanosec-onds (9.65), 15-20 nanoseconds (10.83), and 20-30 nanoseconds (13.77). In order to maintain consist-ency across the survey area, these values were aver-aged (excluding 0-5 nanoseconds), which produced a result of 10.66. All profiles and processed maps were converted from time (nanoseconds) to depth (centimeters) using this average velocity (Conyers and Lucius 1996).

Amplitude slice maps were created in RADAN 7 (Version 7.0.2.4). Many anomalies were visible in multiple slices, which was an important factor in determining the number of slices and their thicknesses. The slice parameters had to be adjusted for both antennas to accommodate the different profile depths (Table 1). For the 400 MHz dataset, slice thickness was 20 centimeters with a 10-centimeter gap between each slice, encompass-ing a total depth of 10-150 centimeters. For the 200 MHz, data slice thickness was 50 centimeters with a 10-centimeter gap between slices encompass-ing a total depth of 20-430 centimeters.

All slices were further processed in Archae-oFusion, a software program that is optimized for archaeological geophysics (Ernenwein et al. 2012). The primary goal of this step was to integrate indi-vidual grids into site-wide mosaics for each depth slice. Additional processing was also performed to eliminate striping, resample data, and minimize edge discontinuities between individual grids (Er-nenwein and Kvamme 2008).

tor. Individual grid points were then marked on the ground to facilitate data collection.

The GPR survey was conducted by two teams, each using a GSSI SIR-3000 system, four-wheeled cart, and either a 400MHz or 200MHz antenna. Instrument gain settings were set to local conditions based on subtle changes in the relative dielectric permittivity (RDP) (Conyers 2004). The entire study area was first covered with the 400MHz antenna using a time window of 35 nanoseconds (Figure 4). Subsequent sampling was conducted us-ing a 200MHz antenna in selected areas using a time window of 150 nanoseconds (Figure 4). Field tests and data processing indicated signal attenua-tion was a consistent problem across much of the study area that limited effective depth penetration from both antennas to approximately two meters (although there were exceptions).

It is generally standard practice to orient transects perpendicular to the long axis of expect-ed features, if known. To maintain consistency and simplify data processing, collection orientation for all data (400MHz and 200MHz) was east-west (along the X axis) with one-meter profile intervals. Additional survey was conducted in selected grids using the 400MHz antenna at 50-centimeter pro-file spacing in a north-south orientation (Y axis). This was done to generate higher resolution data for features of particular interest.

Organized data processing was required due to the sheer volume of GPR data, the short time allotted for field data collection, and com-pressed project schedule. Our priority was to cre-ate three-dimensional imagery of the entire survey area for interpretation, and then supplement those plan view maps with two-dimensional profile anal-ysis.

The first task in data processing was to set “time zero”. This is critical to getting accurate results when elapsed time is converted to target depth. The time-zero position was selected as the mid-point between the first positive and negative ground waves. Next, an overall background filter was applied to the data, which removes the hori-zontal banding that can result from antenna en-ergy “ringing” and outside frequencies such as cell


Figure 4. GPR profile of 400MHz and 200MHz data.

The final step was to incorporate all of the sliced mosaics into ArcGIS 10 (Figures 5-9). Indi-vidual anomalies were then digitized as polygons with corresponding attributes such as anomaly ID, UTM coordinates, depth, and interpretation. The results could then be used to generate maps and tables based on specific queries.

IDENTIFICATION OF ARCHAEOLOGICAL FEA-TURES

In any archaeological geophysical survey the major goal is to produce imagery that can be

used to locate, identify, and, interpret potential cultural features (Kvamme et al. 2006:234). This is a multi-step process that requires extensive knowl-edge and experience with both geophysical instru-mentation (i.e., how and what is measured) and archaeology (i.e., the range of cultural features that might exist) (Kvamme et al. 2006). Kvamme et al. (2006) outlined an “anomaly classification system” that was important for the current study. A range of potential feature types was developed based on the archival research results and previous archaeo-logical experience in urban settings (Patch and Bot-wick 2012). Historic maps in particular provided


Antenna Frequency Slice Position (cm) Slice Thickness (cm)

400 MHz (1-m spacing) 10-30 20

40 - 60 20

70 - 90 20

100 - 120 20

130 - 150 20

400 MHz (0.5-m spacing) 10-30 20

40 - 60 20

70 - 90 20

100 - 120 20

130 - 150 20

200 MHz (I9, H7, H8, H9, F9) 10-40 30

50 - 80 30

90 - 120 30

130 - 160 30

170 - 300 30

200 MHz (H13, H14, H15, I16, J15) 20 - 70 50

80 - 130 50

140 - 190 50

200 - 250 50

260 - 310 50

320 - 370 50

380 - 430 50

Table 1. Slice parameters for 400MHz and 200MHz datasets.

insight into feature location, orientation, layout, and size.

Archaeological interpretations of the GPR anomalies (n=243) was based on the amplitude slice maps (both 400MHz and 200MHz data), two-dimensional profile analysis, and comparison with historic maps (Figure 10, Table 2). Spatial distribution of the feature classes is valuable for identifying broad patterns across the study area. The 243 anomalies were assigned to seven feature classes based on their reflection properties, geom-etry, depths, and correlations with historic maps and aerial photographs. The vast majority of these (n=241) are located in the upper 1.5 meters of the profile, with two additional anomalies between 1.5 and 4.3 meters.

Rail-related features (n=106) are the most common type, accounting for approximately 44 percent of the total (Table 2, Figure 11). This class includes objects such as track, ties, gravel/fill, and compacted surfaces associated with the grade itself and/or adjacent areas that may have served as par-allel work zones. They are distributed throughout the study area and form prominent components of the archaeological landscape. Most rail features correlate very well with rail systems as depicted on a range of historic maps and aerial photographs. Morphologically they are clearly linear, relatively narrow, and vary in length. Several features along the western edge of the study area appear to be seg-mented and those on the eastern edge are intact. In profile, rail features are dense clusters of high


Figure 5. Amplitude slice map from 10-30cmbs.









Figure 10. Total set of anomalies identified in the project area, without interpretation.


Figure 11. Rail features make up 44% of the total identified anomalies.


roundhouses contained stalls radiating from the center for individual engines with adjacent pits where work crews could service the underside of the locomotive. Although the physical location does not line up perfectly with any of the historic maps, it is close enough to be within the margin of error based on issues regarding scale and geo-referencing.

Anomalies 234-237 may be associated with a second roundhouse depicted on the 1899 San-born map. They are located in close proximity and there are no other structural elements in this area on subsequent maps that are comparable. Al-though they range in depth from 20-100 cm below ground surface, they are situated slightly lower in the profile, which suggests they may be earlier fea-tures.

Debris scatters (n=26) account for approxi-mately 11 percent of the total (Table 2, Figure 15). This category includes anomalies that are relatively large and amorphous. Expected feature types in this class include trash scatters, debris fields, struc-tures lacking good outlines, trash pits or disposal areas, or fill episodes (Bevan 2006). Their GPR properties are generally high amplitude reflections consisting of a series of point reflections (Figure 16). Many of these could be the result of building demolition and the resulting “smears” as material was moved around. Spatially, these are distributed throughout the project area with no obvious pat-terning. There are noticeable areas void of debris in the northwest and south-central sections, and very few anomalies in the far southern section. The areas without debris tend to correspond to areas with high concentrations of rail features as noted above. Unknown features (n=26) account for approximately 11 percent of the total (Table 2, Figure 17). It is impossible to identify and articu-late the full range of potential features. Many of the compacted surfaces could not be clearly associ-ated with map-depicted features or further inter-pretations (Figure 18). However, the “Unknown” category was used sparingly and only as a last resort when a particular anomaly could not be directly associated with historic mapping or assigned to another category based on its geometry. Spatially,

amplitude reflections with clear horizontal surfac-es (Figure 12). GPR characteristics suggest that in most cases the track itself had been removed (ex-cept for active lines).

Structural remains (n=64) account for ap-proximately 27 percent of the total (Table 2, Figure 13). This class includes primarily architectural fea-tures such as building outlines, foundations, base-ments, intact wall segments, and presumed floors (Bevan 2006). Morphologically these tend to have regular, patterned outlines in plan view that may or may not correlate with historic maps. Spatially, these are distributed throughout the study area, with no easily defined clusters. Historic maps indi-cate a range of potential features such as commer-cial/industrial buildings, freight sheds, workshops, the W&ARR roundhouse, and an unnamed roundhouse.

Anomaly 209 is of particular interest be-cause of its morphological characteristics. In plan view, it is approximately circular or square. In pro-file it appears as a large basin-shaped feature with a clear bottom that is consistent with a floor or other durable surface (Figure 14). Vertically, it is located between approximately 30 and 120 cmbs. Rail anomalies 18, 19, 205, 206, 207, and 208 are in direct association to the north and south, giv-ing the overall appearance of a wheel with spokes. Railroad turntables for steam engines required very similar conditions for operation, with a deep pit that was semi-circular in cross-section. Along with the central pit containing the turntable,

Table 2. Anomaly classification groups.

Feature Class Total

n %

Rail 106 43.57

Structural remains 64 26.56

Debris 26 10.79

Unknown 26 10.79

Utility 12 4.98

Topography 5 2.07

Surface 4 1.24

Grand Total 243 100.00


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Figure 13. Structural remains make up approximately 27% of total identified anomalies.


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Figure 15. Debris make up approximately 11% of the total identified anomalies.


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Figure 17. Anomalies that could not be categorized make up approximately 11% of the total identified anomalies.


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these are distributed throughout the study area with no obvious patterning. However, there are virtually no features of this type in the southeast-ern, extreme southern, and far eastern sections. These are areas that tend to have high concentra-tions of rail features.

Utility features (n=12) account for approxi-mately five percent of the total (Table 2, Figure 19). These anomalies tend to be linear and have clear hyperbolic reflections in multiple, consecutive profiles (Figure 20). However, it is almost impos-sible to distinguish between historic and modern utilities based on GPR data alone. Potential his-toric features might include sewer drains and water pipes that existed in the Gulch. Modern utilities include fiberoptics, water and sewer lines, natural gas lines, and conduit for electric service. Spatially, these are distributed in the northwest and extreme southern sections of the study area.

Topographic features (n=5) account for approximately two percent of the total identified anomalies (Table 2, Figure 21). This category in-cludes landscape elements such as slope, stratig-raphy, and other geomorphic elements. Some of these topographic changes may be man-made and others appear to coincide with natural topography changes noted on historic maps. It would not be possible to see natural topography in areas with a large amount of fill deposits, but 183 and 239 may be reflections off the slope at the edge of the ra-vine (Figure 22). Leveling the fill areas, excavating through the existing ground surface, or deposit-ing a new layer of different materials would create man-made topography. It is extremely difficult to determine whether a feature should be considered man-made or natural as, typically, deposition and removal activities are not documented in historic records. Some natural topography is noted on his-toric maps, although this is not necessarily com-plete. Spatially, these topography features are re-stricted to the northern and central sections of the survey area.

Surfaces (n=4) account for approximately one percent of the total (Table 2, Figure 23). These appear as large, amorphous, broad areas with gen-erally high amplitude reflections (Figure 24). They

likely formed as a result of greater compaction, heavier use, and/or pooled moisture.. Potential activities might include roads, exterior work areas, cleared zones around buildings, and parking/stor-age lots. Spatially, there is little to note in the way of patterns.

RESEARCH THEMES AND ARCHAEOLOGICAL INTERPRETATIONS

Research themes were developed for the original study including 1) the development of topography, 2) the range of archaeological feature types, 3) effects of the Civil War, 4) transportation, and 5) changing land use (Patch et al. 2013). As a result of that study multiple datasets and lines of evidence were generated or examined. Archival research provided a highly detailed context for un-derstanding the history of the study area that was particularly useful for identifying a range of expect-ed feature types. Historic map review indicated the locations and types of features that existed at vari-ous points in time as well as changes in the overall landscape. Soil coring yielded information regard-ing the original topography of the Gulch, depth of deposits, and nature of the fill events and episodes. GPR survey mapped an extensive distribution of archaeological features.

There is abundant evidence from all data-sets for major changes in topography of the Gulch from the 1850s to today. Archival research defined broad trends in development that was further re-fined through historic map review. Core results in-dicate a complex depositional history with evidence for multiple layers of deep fill and reworked de-posits that suggests relatively rapid and intentional burial. Soil core descriptions and corresponding artifact analysis indicate this process was underway as early as the mid-nineteenth century, although at a relatively slow pace. By the late 1890s the remain-ing section of the ravine was filled rapidly and the entire area was brought up to the current grade. GPR survey identified at least a few topographic features that correspond to later fill events.

All four datasets yielded information re-garding the range of archaeological features. Ar-chival research and mapping indicated rail lines,


Figure 19. Utilities make up approximately 5% of the total identified anomalies.


Figure 20. Exam

ple of a utility in profile.


Figure 21. Topography makes up approximately 2% of the total identified anomalies.


Figure 22. An exam

ple of topography in profile.


Figure 23. Compacted surfaces make up approximately 1% of the total identified anomalies.


Figure 24. Exam

ple of a compacted surface in profile.


freight shops, platforms, and work yards. Soil cor-ing indicated a high degree of variation in the na-ture and type of fill deposits. GPR data were the most informative in terms of archaeological. Over-all, the data are skewed toward features that are larger, denser, and higher contrast; it was not pos-sible to identify individual artifacts or very small deposits. The types of features that were identified include rail lines, beds, track segments, building footprints, foundations, basements, utilities, de-bris scatters, and landform elements.

There is little direct evidence related to the effects of the Civil War from any of the data-sets other than archival research. No artifacts or features were identified that could be directly as-sociated with any Civil War activities. Destruction from Civil War battles and the subsequent burn-ing of Atlanta likely removed most traces of ma-jor features that existed at that time. Because the ravine was still a major landscape feature at that time it may have served as a convenient location for refuse disposal that would be very deep. The GPR data did reveal a small number of features that may represent traces of the original W&ARR roundhouse. The lack of good data on the round-house is likely due to complete destruction of its physical remains and footprint or it is beyond the depth range of GPR detection limits regardless of antenna frequency. Potential archaeological re-mains from this period are likely not substantial, and there are no intact patterns identified with the current methodology.

The archival research, historic map, and GPR datasets all provided significant information regarding the transportation history of the Gulch. Early rail corridors were heavily influenced by to-pography in the Gulch because it provided a path of least resistance compared to surrounding areas. Once these locations were fixed Atlanta’s future development was intimately connected to trans-portation. Trolley systems became a major trans-portation mode for Atlanta at a very early date (Sullivan et al. 2012). GPR data mapped locations and conditions of rail features, associated work ar-eas, and structural remains. This is not surprising given their high contrast and archaeological visibil-

ity. The transportation aspect of the Gulch is still visible today.

All four datasets support an interpretation of land-use continuity through time. At a broad level land use in the MMPT area was relatively con-sistent from approximately the 1850s through the 1960s. During that period of time, it served as a major rail and transportation hub for Atlanta itself and provided links to other areas of the country. Landscape development reflected this importance and left its imprint on the area. Although the scale and intensity have declined in recent decades, transportation continues to be a major aspect of the Gulch. The geophysical anomalies and corre-sponding interpretations all relate to transporta-tion, industrial, and commercial uses of the area throughout its history.

INTEGRITY

Integrity, or physical condition, of archaeo-logical resources is a critical aspect of the Section 106 process. This generally refers to the degree to which artifacts, features, and sites have been impacted or affected since their formation and whether or not they convey their significance. The level of integrity of features depends on a number of variables, including age, material composition, location, and how much subsequent disturbance has occurred. As a general rule, larger objects constructed of more durable materials will tend to be more resistant simply because of their size and mass. GPR data provide the best estimate of archaeological integrity in the Gulch.

Rail features provide a good proxy for as-sessing potential integrity because of their frequen-cy and spatial distribution. Many are first visible between 10 and 30 centimeters of the surface and some extend to depths beyond one meter. The vast majority of rail features appear to be intact in the northeastern and southeastern sections, yet much more segmented along the western side, which suggests different levels of integrity. Intact rail fea-tures appear to have had the track removed and then simply paved over, preserving the grade and alignment. At the other end of the spectrum, rail features on the western side appear to have been


deliberately and more completely removed leaving only small segments.

Depth does not appear to be an important factor in their integrity and condition. The highly segmented lines in the western area and relative lack of rail features on the extreme eastern edge are likely the result of major disturbances and deliber-ate removal of grades and alignments. Although somewhat counterintuitive, the more intact seg-ments are located under the CNN deck and in the parking lot to the south. This suggests that rela-tively little disturbance occurred as a result of con-struction and overall feature preservation may be high. The zone with highest integrity is bounded on the west by an inactive but still present track leading approximately north-south, on the north by Centennial Olympic Park Drive, on the east by the Spring Street Viaduct, and on the south by the MLK Viaduct. That is not to say that additional areas do not have intact features, only that rail fea-tures are better preserved in these areas.

Given the overall number of features, di-versity of types, and their spatial distribution, the archaeological integrity of the Gulch is relatively high, despite known development. Therefore, fea-ture preservation should be good, with intact re-mains, deposits, and sufficient context for further research.

NRHP EVALUATION The Section 106 process requires identifi-

cation of archaeological sites (and other historic properties), evaluation of their significance accord-ing to National Register of Historic Places (NRHP) criteria, assessment of potential effects, and reso-lution of adverse effects through avoidance, mini-mization, or mitigation. The present study is an example of an alternative, yet equivalent, approach to archaeological survey. The geophysical survey has generated primary data that can now be used to evaluate the archaeological landscape of the Gulch for the National Register of Historic Places (NRHP).

Because of its size, scale, and complexity, the MMPT study area is an excellent example of an urban archaeological site, and it has been desig-

nated as 9FU584. It is comprised of numerous fea-tures from different periods and activities and rep-resents a unique chance to generate information about a major, yet poorly understood, aspect of At-lanta’s history. Features within the landscape are all connected by their physical proximity to each other and their association with the broad trans-portation theme. Based on information obtained from archival research, historic maps, soil coring, and GPR survey, it was recommended eligible for the NRHP under Criteria A and D at the regional level of significance.

Site 9FU584 meets Criterion A because it is directly associated with a pattern of events that was critical to the founding and development of Atlanta. Its archaeological remains reflect the im-portance of transportation networks (rail in par-ticular) in Atlanta’s history. Atlanta’s growth in its early years was a direct result of transportation infrastructure. The Gulch was so important to this development that it left a physical imprint on the city’s layout that is still visible today. It retains es-sential physical features that made up its character and appearance during its period of significance.

Site 9FU584 meets Criterion D because of the number, density, diversity, and information po-tential of the features identified in the GPR survey. As noted above, these features reflect a full range of transportation and industrial activities. Their spatial distributions and good physical integrity make them likely to yield significant information regarding a number of research questions.

CONCLUSIONS

Multiple datasets were generated to pro-vide the maximum amount of information on potential archaeological features. The GPR data-set was used to detect, image, and map subsurface features over a large area in great detail, address broad research themes, assess integrity, and evalu-ate the Gulch for the NRHP (Kvamme 2003:435). The size of the study area and amount of informa-tion that is now available enabled broad inferences about the archaeology in a way not possible with standard techniques.


Based on this survey we now know what types of features to expect, their spatial distribu-tion, suspected stratigraphy, depths of potential deposits, an estimate of the original landform prior to historic alterations, and what types of activities were conducted. Recommendations for management and treatment were based on all lines of evidence but with a specific focus on the GPR anomalies because they represent tangible archaeo-logical resources that are likely to be impacted. The previous discussion has demonstrated several ways geophysical data can be used in a cultural resources management setting.

ACKNOWLEDGMENTS

This project was the result of extensive collaboration, consultation, and cooperation among multiple individuals. The Georgia Department of Transportation and HNTB Corporation were the primary institutional drivers of the work. Sara Gale, for-merly with GDOT and now with Geophysical Survey Systems, Inc. (GSSI) deserves recognition for her support of a geophysical survey of this magnitude. After her departure, Terri Lotti, also with GDOT, adeptly handled the transition and nurtured the project to comple-tion. This study is a testament to GDOT’s longstanding, early, and highly influential use of geophysics over the past ten years.

Lynn Pietak and Dylan Woodliff, at Edwards-Pitman Environmental, Inc. (EPEI) conducted all the archival and back-ground research for this project. Keith Seramur and Matt Mat-ternes worked on the soil coring and associated artifact analysis, respectively. Adam Archual at HNTB was involved in all aspects of the geophysical fieldwork. Charlotte Weber, also at HNTB, was re-sponsible for keeping us on schedule and providing a comprehensive technical review. Eileen Ernenwein and Elsa McMakin of Foxfire Geophysics assisted with data processing. Daniel Bigman and one anonymous reviewer offered constructive comments and suggestions that improved the overall quality of this paper. All of these individu-als are thanked for their efforts.

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Documents

Archaeological Geophysics Survey of Atlanta's Gulch