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This section provides general information on land uses, potential receptors, and sensitive environmental areas at CSSA.

3.1 - Land Use Survey

In accordance with the TNRCC TRRP, a land use survey was completed December 15 and 16, 1999, covering the area within a 1-mile radius of CSSA. Preliminary land use information was obtained from Texas highway maps, United States Geologic Survey (USGS) topographic maps, and aerial photography. The surrounding area was surveyed on foot and by vehicle as accessible from public roads and CSSA property. Preliminary land use information was updated when discrepancies were observed.

Figure 1.1 illustrates the general land uses in the area. Land use is primarily single-family residential, with a smaller amount of commercial use. CSSA is bordered to the west by Ralph Fair Road. Scattered residences and undeveloped land lay west of Ralph Fair Road, with residential density increasing in the city of Fair Oaks, located northwest of CSSA. Fair Oaks Elementary School is located just northwest of CSSA. A retail gas station is located just outside the northwest corner of the facility boundary. The northern boundary of CSSA is bordered by a single residence on the western side, with undeveloped land used for cattle grazing; and the adjacent Camp Bullis Army training installation on the eastern side. Camp Bullis also forms the entire eastern boundary and part of the southern boundary. The remaining area south of the facility contains single family residential housing units.

The mission of CSSA is not anticipated to change; therefore, land use changes on the facility are not anticipated. Land use in the surrounding area is not anticipated to change, except for increased residential development in undeveloped areas west and north of CSSA. Increased residential development is anticipated to result in increased demand on the public water supply, which is supplied from local wells.

There are three aquifers underlying CSSA, the upper, middle, and lower Trinity aquifers. The lower Trinity aquifer is not a primary drinking water source, due to high cost to develop wells and because it often yields mineralized (saline) water. The middle Trinity aquifer consists of the Cow Creek limestone, the Hensell Sand/Bexar Shale, and the lower Glen Rose members of the Travis Peak Formation. A number of wells on CSSA are reportedly in both the Cow Creek and lower Glen Rose. Movement of groundwater in the aquifer is toward the south and southeast, but heavy pumping or periods of extended drought have been observed to affect the direction of groundwater flow. The middle Trinity aquifer is the most widely used source of water in the area. The upper Trinity aquifer consists of the upper Glen Rose limestone, which is exposed over much of CSSA. Upper Trinity water is generally of poor quality due to excessive sulfate, and production is low (Parsons ES, 1998).

Periodic sampling of wells on CSSA and the surrounding area has been conducted since 1991. Elevated VOCs have been detected in Wells 1, 2, 3, 4, MW1, MW2, Well D and Well 16. Wells 2,3,4, MW1, MW2 and Well D are completed in the lower Glen Rose, while Wells 1 and 16 are completed in the Lower Glen Rose and Cow Creek. Well 1 is located on Camp Bullis property, and the remainder are located on CSSA. Additional monitoring wells are proposed to be drilled in the lower Glen Rose, Bexar Shale, and Cow Creek formations to further define the groundwater plume and obtain more detailed information on direction of groundwater flow. Also, additional sampling of off-site wells is proposed.

The limestone formations underlying CSSA are fractured and porous and exhibit vertical faulting. Fractured limestone features have been observed on CSSA in rock outcrops and in creek beds, which are potential groundwater recharge avenues.

Parsons ES is in the process of conducting a detailed water well search in the CSSA vicinity. Numerous water wells are located within � mile of the facility. Most of the wells are private residential wells or production wells for the Fairco Water system, which services approximately 1,770 connections in the Fair Oaks subdivision just northwest of CSSA. All Fairco wells are over 400 feet deep, open-hole completions in the Lower Glen Rose and Cow Creek aquifers (Murphy, 1999). Fairco also operates a few Lower Trinity wells (Sligo and Hosston completions) but use the water for golf course irrigation because it is too mineralized for human consumption. Bexar Metropolitan Water District owns and operates eight public supply wells within � mile of the southern base boundary. These wells supply water to the Leon Springs Villas and Hidden Springs subdivisions (approximately 800+ residents) (CSSA, 2000).

Three intermittent streams serve as drainage ways for CSSA (Parsons ES, 1998). Salado Creek begins approximately 1 mile west of CSSA and flows across the facility generally from northwest to southeast. Several unnamed tributaries of Salado Creek are also located within facility boundaries. Cibolo Creek is located north of CSSA, as close as approximately � mile from the northern CSSA boundary. Cibolo Creek flows west to east in this area. Leon Creek flows generally northwest to southeast through the City of Leon Springs, which is southwest of CSSA. Leon Creek is as close as approximately � mile from the CSSA boundary.

CSSA is in the watersheds of all three creeks. Most of the facility drains to the Salado Creek watershed. The northeastern corner of the facility falls in the Cibolo Creek watershed, while the southwestern corner occurs in the Leon Creek watershed. The creeks were dry at the time of the field survey, but can carry substantial flow after rainfall events.

No springs were observed during field surveys; however, intermittent springs or seeps occur in the area after rain events. One spring is delineated on the USGS topographic map near the City of Leon Springs, approximately 1 mile from the CSSA boundary.

A wetlands delineation has been previously performed for CSSA (SAIC, 1997). Four jurisdictional wetlands were delineated, all occurring within the channel of tributaries of Cibolo Creek or Salado Creek. Seven additional impoundments or wetlands which were not considered jurisdictional were also delineated. Most of the wetlands or impoundments occur in drainages that have been excavated or where an embankment or road impedes flow and allows water to collect. There are also several small impoundments or potential wetlands within � mile of the facility, where drainages have been blocked with embankments to impound water or where water backs up behind road crossings and may collect for a period of time.

There are no wildlife management areas or other sensitive environmental areas within � mile of the CSSA boundary. Some land within CSSA is managed for wildlife as discussed below in the "Ecological Receptors" section.

3.2 - Receptor Survey

A more intensive survey was conducted within a �-mile radius of CSSA to identify potential receptors, points of human exposure, and possible constituent pathways. Locations of sensitive human receptors such as schools, day care facilities, and recreational facilities were noted.

As shown on Figure 1.1, land use surrounding CSSA is primarily residential. Sensitive receptors observed within the �-mile radius include children attending Fair Oaks Elementary School, located just northwest of CSSA. The area south of the facility is fairly densely populated, with trailer homes located on small lots. Homes are only sparsely scattered along most of the western boundary; however, there is much undeveloped land that has potential for additional residential development.

Living quarters and work areas in Camp Bullis are located approximately 3 miles away from the common boundary with CSSA. One classroom is located approximately � mile southeast of Gate 8, but is scheduled to be abandoned in about 1 year. Field training exercises may be conducted anywhere within Camp Bullis. An individual trainee may be located at Camp Bullis for training for anywhere from 1 day to 3 weeks, with an average duration of approximately 5 days. Training exercises may include time on foot and/or in vehicles (Bruins, 2000).

Within CSSA, there is a full-time work force of approximately 100 persons working in shops and office buildings. Personnel also work outdoors throughout the facility to perform maintenance activities such as road and fence maintenance, brush clearing, and security patrols. Approximately 25 people, including children, occupy seven residences on the CSSA facility. The location of the residential area on CSSA is shown in Figure 1.1.

CSSA contains mostly forested, undeveloped land, various portions of which are being managed to promote different species. Some areas are managed to maintain habitat for two endangered bird species, the golden-cheeked warbler and the black-capped vireo. The native white-tailed deer and introduced axis deer populations are also managed, and controlled hunting is allowed. Management practices which benefit the deer and other wildlife species include maintenance of feed plots, feeding and watering stations, and clearing of Ashe juniper to improve habitat. Other areas are managed as pastures for grazing by cattle. The evaluation of ecological receptors will examine potential pathways such as use of watering facilities (from groundwater) and surface water by wildlife, and contact with soil and sediment. Potential pathways are discussed in more detail in the next section.

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