M A S T E R   P L A N

Section 5

ENVIRONMENTAL OVERVIEW

An environmental inventory, general in nature and focused on environmental issues that were deemed pertinent to the Athens/Ben Epps Airport Master Plan Update, was performed. The issues evaluated include:

• Noise;
• Historic and Archaeological Resources;
• Threatened and Endangered Species;
• Wetlands;
• Floodplains; and,
• Hazardous Materials.

This overview was based on a review of available resource materials, including, but not limited to the United States Geological Survey (USGS) Athens East, GA, 7.5 minute series topographic map (dated 1964, photorevised 1986); a color aerial photograph (dated August 1, 1997); Georgia Department of Natural Resources (GADNR), Historic Protection Division, National Historic Register listings in Clarke County (database updated May 1, 2002); the University of Georgia, Georgia Site File Database of known historic and archaeological sites (review performed August 7, 1998); GADNR Natural Heritage Programs list of known rare species occurrences in Clarke County (dated October 16, 2001); United States Fish and Wildlife Service (USFWS) list of known protected species for Clarke County (updated June 2002); USFWS Athens East, GA, National Wetland Inventory (NWI) map; the Natural Resource Conservation Service (NRCS) Soil Survey for Clarke and Oconee Counties (issued November 1968); the GADNR Environmental Protection Division (EPD) Hazardous Site Inventory (HSI, dated July 1, 2001); and the Federal Emergency Management Agency’s (FEMA), Flood Insurance Rate Maps (FIRM, Panel number 130040-0030-C, dated May 4, 1992). It should be noted that limited field reconnaissance of the study area was performed in 1998.

Environmental concerns identified in the study area were digitized onto a base map and are depicted on Figure 5-1.

5.1 Noise

Aviation noise has been a constant concern of communities and airports since the introduction of the jet engine to commercial aviation in the early 1970’s. The Airport Noise and Capacity Act (Noise Act) passed by Congress in 1990, created noise standards for aviation. Associated with the standards was the gradual phase out of older and noisier, Stage 2 aircraft and transition to quieter, Stage 3 aircraft (to be completed by January 2000). This phase out and Stage 2/3 descriptors applies only to civil aircraft weighing in excess of 75,000 pounds (i.e., 737-400, 757-200). Although this mandate does not include the majority of corporate business jet operations taking place at AHN, business jet manufacturers have made noted strides in reducing aircraft noise over the last decade, to the point of falling well below the Stage 3 required noise levels. As older business jet technology is replaced by more efficient newer models, noise levels will significantly decrease.

FAA’s Integrated Noise Model (INM), version 5.1, was utilized to assist in the review of potential noise impacts for the various development scenarios. The analysis used the Day-Night Average Sound Level (L_dn or DNL) noise metric as a descriptor of cumulative aircraft noise exposure. L_dn is a 24-hour logarithmic average of noise levels in A-weighted decibels (dB), as recommended by the FAA for evaluating aircraft noise impacts. The L_dn noise metric was developed by the Environmental Protection Agency and is used by the FAA, the Department of Housing and Urban Development, and other federal agencies concerned with community noise levels.

Figure 5-1

Click picture for larger version

Noise contours generated by the FAA INM do not depict a strict demarcation of where the noise levels end or begin. Their purpose is to describe the generally expected noise exposure. The noise contours represent average annual conditions rather than single event occurrences. Noise exposure on any one day may be greater or less than the average day. The noise model is useful for comparison of noise impacts and can provide a reasonable basis for performing airport noise compatibility planning.

Based on flight track and runway end utilization data gathered as a part of earlier phases of the Master Plan Update, future 2017 noise contours were generated for four runway extension alternatives, including the no-build option. These original noise contours are depicted on Exhibits 9 and 10 in Appendix III, "Runway 9/27 Extension Feasibility." Figure 5-1 depicts the 65 L_dn contour for the selected runway extension to both the west and east.

Although 500-foot extensions are proposed for both runway ends, the 65 L_dn contour extends further to the west since a majority of operations are conducted using a westerly flow and most noise is generated on departure. In that some portions of this 65 L_dn contour fall beyond the existing Airport property line, the identification of land uses and population within these areas may become more critical. For ease of reference, Table 5-1 presents FAA Guidelines and Land Use Compatibility with L_dn Sound Levels (65, 70, 75, etc.). Most land uses, with the exception of residences, schools, and outdoor amphitheaters, are compatible with an airport noise range of 65 L_dn to 70 L_dn or less. This determination is based on the assumption that in most instances a degree of noise attenuation has been incorporated into the design of structures. The 65 L_dn contour is generally accepted as the threshold level at which residential land use is considered compatible. Approximately 6 single-family and 2 multi-family residences and 14 mobile homes are located within the 65 L_dn contour depicted on Figure 5-1. It is important to note that the noise exposure contour depicted on Figure 5-1 does not consider operational noise abatement measures that could reduce potential noise impacts.

 

 

Table 5-1 LAND USE COMPATIBILITY WITH YEARLY DAY-NIGHT AVERAGE SOUND LEVELS Athens/Ben Epps Airport
	Yearly day-night average sound level, Ldn in decibels
LAND USE	Below 65	65-70	70-75	75-80	80-85	Over 85
Residential Use
- Residential, other than mobile and transient lodgings - Mobile home parks - Transient lodgings	Y Y Y	N(1) N N(1)	N(1) N N(1)	N N N(1)	N N N	N N N
Public Use
- Schools - Hospitals and nursing homes - Churches, auditoriums and concert halls - Government services - Transportation - Parking	Y Y Y Y Y Y	N(1) 25 25 Y Y Y	N(1) 30 30 25 Y(2) Y(2)	N N N 30 N(3) Y(3)	N N N N Y(4) Y(4)	N N N N Y(4) N
Commercial Use
- Offices, business and professional - Wholesale & retail - building materials, hardware, & farm equipment - Retail trade - general - Utilities - Communication	Y Y   Y Y Y	Y Y   Y Y Y	25 Y(2)   25 Y(2) 25	30 Y(3)   30 Y(3) 30	N Y(4)   N Y(4) N	N N   N N N
Manufacturing and Production
- Manufacturing (general) - Photographic and optical - Agriculture (except livestock) and forestry - Livestock farming and breeding - Mining and fishing, resource production and extraction	Y Y Y Y Y	Y Y Y(6) Y(6) Y	Y(2) 25 Y(7) Y(7) Y	Y(3) 30 Y(8) N Y	Y(4) N Y(8) N Y	N N Y(8) N Y
Recreational
- Outdoor sports arenas and spectator sports - Outdoor music shells, amphitheaters - Nature exhibits and zoos - Amusements, parks, resorts and camps - Golf courses, riding stables and water recreation	Y Y Y Y Y	Y(5) N Y Y Y	Y(5) N N Y 25	N N N N 30	N N N N N	N N N N N

 

Table 5-1 (cont.) LAND USE COMPATIBILITY WITH YEARLY DAY-NIGHT AVERAGE SOUND LEVELS Athens/Ben Epps Airport
NOTES FOR TABLE 5.1
SLUCM	Standard Land Use Coding Manual
Y (Yes)	Land Use and related structures compatible without restrictions.
N (No)	Land Use and related structures are not compatible and should be prohibited.
NLR	Noise Level Reduction (outdoor to indoor) to be achieved through incorporation of noise attenuation into the design and construction of the structure.
25, 30, or 35	Land use and related structures generally compatible; measures to achieve an NLR of 25, 30 or 35 dB must be incorporated into design and construction of structure.
Where the community determines that residential or school uses must be allowed, measures to achieve outdoor to indoor Noise Level Reduction (NLR) of at least 25 dB and 30 dB should be incorporated into building codes and be considered in individual approvals. Normal construction can be expected to provide an NLR of 20 dB, thus, the reduction requirements are often stated as 5, 10 or 15 dB over standard construction and normally assume mechanical ventilation and closed windows year round. However, the use of NLR criteria will not eliminate outdoor noise problems. Measures to achieve an NLR of 25 dB must be incorporated into the design and construction of portions of these buildings where the public is received, office areas, noise sensitive areas, or where the normal noise level is low. Measures to achieve an NLR of 30 dB must be incorporated into the design and construction of portions of these buildings where the public is received, office areas, noise sensitive areas, or where the normal noise level is low. Measures to achieve an NLR of 35 dB must be incorporated into the design and construction of portions of these buildings where the public is received, office areas, noise sensitive areas, or where the normal noise level is low. Land uses compatible, provided special sound reinforcement systems are installed. Residential buildings require an NLR of 25. Residential buildings require an NLR of 30. Residential buildings not permitted.
SOURCE: Federal Aviation Administration.

 

5.2 Historic and Archaeological Resources

Section 106 of the National Historic Preservation Act, Protection of Historic and Cultural Resources, requires agencies to consider the effects of their actions on sites listed on the NRHP and sites that are eligible for listing. Historic and archaeological sites, including structures such as houses, churches, monuments, and cemeteries, as well as prehistoric sites, should be avoided wherever possible when constructing or performing improvements at airports. In addition, sites not formally eligible for listing and sites discovered during planning or construction of a project should also be considered.

Records of known historic structures and sites listed on the NRHP that are located in Clarke County are maintained by the Historic Preservation Division of GADNR. This list was reviewed to determine if any known listed sites are located in the study area. Based on a review of GADNR records, there are no known NRHP sites listed, or eligible for listing, within the study area.

The University of Georgia maintains the Georgia Site File Database Records of known historic and archaeological sites. Based on a review of this database, there are two known sites located within the study area (see Figure 5-1). One site, which is located in the western portion of the study area, is comprised of both historic and archaeological materials, and is recommended for listing on the NRHP. The status of the other, an archaeological site located in the northern portion of the study area, has not been assessed. Additionally, a cemetery is indicated adjacent and southeast of the northern end of Runway 2/20.

Although no historical or archaeological sites listed on the NRHP are known within the study area, a field survey for sites potentially eligible for listing on the NRHP in the study area may need to be performed by qualified personnel prior to implementation of the proposed improvement projects. Furthermore, the status of the two known historic/archaeological sites and cemetery would need to be assessed.

5.3 Threatened and Endangered Species

The Endangered Species Act of 1973, as amended, gives the Secretary of the Interior, acting through the USFWS, and the Secretary of Commerce, acting through the National Marine Fisheries Service, the power to protect and conserve all forms of wildlife and plants deemed to be in serious jeopardy.

By federal definition, an endangered species is any species of fish, wildlife, or plant that is in danger of extinction throughout all or a significant portion of its range. A threatened species is any species likely to become endangered within the foreseeable future throughout all or a significant portion of its range. These endangered or threatened determinations are based on: loss or modification of habitat; over utilization; disease or predation; lack of regulations or enforcement; or other natural or manmade factors affecting the continued existence of a species. Species identified as in need of protection are placed on the federal list. Any species that is officially proposed for inclusion on the list as threatened or endangered is given the same protection as listed species.

Federally protected species known to occur in Clarke County, their status, and notes on their habitat can be found in Table 5-2. Based on a review of GADNR Heritage Program records, there are no known occurrences of these species within the study area. However, a field survey of potentially suitable habitat may need to be performed during subsequent phases of the proposed improvements.

 

Table 5-2 THREATENED AND ENDANGERED SPECIES KNOWN TO OCCUR IN CLARKE COUNTY, GEORGIA1 Athens/Ben Epps Airport
SCIENTIFIC NAME	COMMON NAME	FEDERAL STATUS	NOTES ON HABITAT AND OCCURRENCES
Haliaeetus leucocephalus	Bald eagle	T	Prefers nesting along major river drainages of the Lower Coastal Plain, usually adjacent to large areas of impounded marshes.
Myotis grisescens	Gray bat	E	Roosts in caves or cave-like habitat.
Picoides borealis	Red-cockaded woodpecker	E	Nests only in mature (trees with a minimum age of 60 years) pine forests and forages in pine stems at least 30 years old (9.8 inches or larger in diameter), usually long-leaf or loblolly, which are fairly open and free of hardwood understory.
1USFWS listing last updated on April 1, 2002. NOTES: E = Endangered T = Threatened

 

5.4 Wetlands

Executive Order 11990, Protection of Wetlands, requires federally supported projects to preserve wetlands and to avoid and minimize wetland impacts to the maximum extent practicable. NWI mapping, the county soil survey, and a color aerial photograph were used to identify potential wetlands and jurisdictional waters of the United States within the study area.

Approximately 45 to 50 acres of potential bottomland hardwood wetlands were mapped in the study area along stream channels, as well as 1 to 2 acres of emergent wetlands, and 3 to 4 acres of open water (see Figure 5-1). Although this level of detail is suitable for this Master Plan Update and for avoidance and minimization of impacts and during initial improvement project phases, wetlands within the construction limits of a proposed improvement would need to be delineated and requisite federal and state permits and certifications obtained prior to beginning construction. Unavoidable impacts would need to be mitigated either by restoration, preservation, enhancement, or creation of wetlands.

5.5 Floodplains

According to Executive Order 11988, Federal Floodplain Management, agencies must reduce the risk of flood loss, minimize the impacts of floods on human safety, health and welfare, and restore and preserve the natural and beneficial values served by floodplains and floodways. The 100-year floodplain delineates the area that would be inundated by a flood of such intensity that its probability of occurrence is once every 100 years. A floodway is a channel of a river or other watercourse and the adjacent land areas that must be reserved in order to discharge the base flood without cumulatively increasing the water surface elevation more than a designated height.

Based on review of FEMA maps and as depicted on Figure 5-1, relatively narrow floodplains (Zone A) and a floodway (Zone AE) associated with Shoal Creek are located approximately 4,500 feet east of the eastern end of Runway 9/27. This designation indicates that this portion of the study area is within the boundaries of the 100-year flood and that base flood elevations and flood hazard factors have been determined. Federal regulations allow development encroachment into the floodplain, but not the floodway (which must be unobstructed to convey the 100-year flood), unless it has been demonstrated through hydrologic and hydraulic analysis that the encroachment will not result in an increase in flood levels. This encroachment must not increase the base flood elevation by more than one foot.

During construction of the proposed improvement projects, local regulations must be complied with and precautions taken to minimize potential impact to the existing floodplain and floodway areas.

5.6 Hazardous Materials

The EPD maintains a Hazardous Site Inventory (HSI) of sites in Georgia that are known or suspected of having had a release of a regulated substance. The HSI was reviewed to determine if any known hazardous material sites are located in the study area. Additionally, the locations of potential sources of contamination that were observed during the site reconnaissance were mapped on the base map (see Figure 5-1). Review of the HSI did not reveal any known hazardous material sites within the study area. However, during a 1998 site reconnaissance, several potential sources for contamination were observed. These included gas stations with underground storage tanks (USTs), automotive repair shops, a dry cleaning facility, a fertilizer production plant, and six excavated USTs and four tanker trucks observed stored on property adjacent to the study area. These sites were located in the southern and western portions of the study area. Because these are potential sources for contamination, a Phase I Environmental Site Assessment should be performed for the study area prior to planning construction in the vicinity of these sites.

Additionally, during the preparation for construction of an extension to Runway 27 in 1994, a former landfill was discovered. The runway extension was constructed over the landfill. According to County officials, municipal garbage had been placed in this landfill, which was closed in 1974. Geotechnical borings in the proposed safety area indicate that the landfill is covered with soil and that the trash layer ranges from 3 to 20 feet thick.

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