ACCESS ENVIRONS 
NATURAL FEATURES CULTURAL-HISTORICAL DEVELOPED FEATURESPARK PROGRAMS ADMINISTRATION-FINANCE
| ACCESS ENVIRONS NATURAL FEATURES |
| CULTURAL-HISTORICAL DEVELOPED FEATURES | |
| PARK PROGRAMS ADMINISTRATION-FINANCE
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C. NATURAL FEATURESThree vegetation zones converge within Bexar County. These include the Blackland Prairies, South Texas Plains and the Edwards Plateau. Elements from each vegetation area can be found within Friedrich Wilderness Park, however the predominant vegetation type is that of the southeast Edwards Plateau. Although most of the Park's vegetation consists of an ashe juniper live oak woodland community, its topographic complexity results in considerable internal plant diversity including several species which are rare or unusual in Bexar County. A detailed baseline inventory of the plants found within the Park is currently being developed and herbarium specimens are being prepared and maintained by FOF. |  Texas alligator lizard on a juniper beside Main Loop Trail |
| The wildlife diversity of Friedrich Wilderness Park reflects the Park's topographic and vegetative diversity and is typical of this part of the Edwards Plateau. Over forty species of butterflies and over one hundred species of birds have been documented at the Park. Nesting habitat for two endangered bird species, the Black-capped Vireo and the Golden-cheeked Warbler, is also well-documented at the Park. A variety of mammals, reptiles, and some amphibians are also present in the Park. Small mammal and reptile inventories are currently being prepared by FOF. The Park's white-tailed deer population is believed to be excessive. Some native plant species have been eliminated and others are threatened by deer over browsing. Considering the Park's objective of maintaining a representative balanced ecosystem, studies supported by FOF are attempting to document the impact of the deer on recruitment and survival of native vegetation. Other mammal related problems are due to loose domestic animals (primarily dogs and cats) from neighbors and visitors. Feral hogs known to be in the area will pose yet another serious threat to the Park's ecosystem should their number increase. Garden plants which may become established in the Park and disrupt the natural balance are becoming a greater concern as urban development approaches the Park boundary. | |
| 2. Geology The Park's geology is typical of the Canyonlands of the Balcones Escarpment. This region occurs along a fault zone where the Edwards Plateau rises abruptly over the coastal plain of the Gulf of Mexico. The limestone substrate of the Park and much of the Hill Country, is comprised of alternate massif (hard) and vugular (soft) layers, giving hillsides a terraced look. Tributaries of many creeks that drain the ten major watersheds of the Edwards Plateau have carved canyons along its edge where elevations rise abruptly. Geologic conditions of the plateau, the coastal plain, and the escarpment have created the Edwards Aquifer and a distinct recharge zone which parallel the escarpment itself. Friedrich Wilderness Park (located over the Glen Rose Aquifer) lies immediately north of the Edwards Aquifer Recharge Zone. The Edwards and Glen Rose are the two geologic formations found within Park. These formations are further subdivided within the Park, and include both the Dolomitic Member (elev. 1280'-1450'; approximately 55 acres) and the Basal Nodular Member (elev. 1230'-1280'; approximately 100 acres) of the Edwards Limestone and the Upper Member of the Glen Rose Formation (elev. 1140'-1230'; approximately 82 acres). Of the three geologic members, the Basal Nodular is the softer of the group and breaks down to form soil more quickly than the formations it is situated between. Differential erosion and solubility of these layers contributes to the horizontally layered appearance of the Park's woodland vegetation. | |
| 3. Hydrology Bexar County rainfall is subject to drought periods every few years but averages about 28" a year with peak periods in April - June and August - October. Heavy downpours are not uncommon, with a peak 24 hour accumulation of 4" at least once in an average two year period, and a 10" downpour at least once in a 100 year period. Given the typically thin soils of the Canyonlands, these rainfall patterns make stormwater erosion a serious problem. Friedrich Wilderness Park is in the Upper Leon Creek Watershed of Bexar County. Very little surface water flows onto FWP land from adjacent properties. Drainage headers within the Park lead runoff away from the land in four directions. Unnamed intermittent stream beds drain about 13% of the Park land across the north boundary, about 18% across the south boundary, and about 19% across the boundary near the Park's southwest corner. About 50% of the Park drains to the east, crossing Milsa Road near the intersection with Oak Road. The north and east drainage joins Leon Creek near Mission Cemetery after crossing I-10. The south and west drainage crosses Heurmann Road and runs alongside Babcock Road until joining Leon Creek near the UTSA campus. |
 The stock tank exhibit on the water trail is the only year-round standing water within the park. |
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Active springs have been identified in the Park only during heavy rainfalls. There are no natural ponds. One windmill and three electric pumps bring water to the surface from ground water sources at four well sites (described in Sections D and E of EXISTING CONDITIONS). 4. Microclimates, Slopes, and Elevation Classification Friedrich Wilderness Park has open slopes and canyons of varying steepness, facing all points of the compass, and at high and low elevations resulting in a great variety of microclimates. Elevations range from about 1150' near Milsa Road to 1450' between the Main Loop Trail and the Vista Loop Trail. The soils found within FWP are comprised of three types, the predominant soil being Tarrant Association, followed in area by the Brackett-Tarrant Association. The clay-loam soils of the area are typically very thin and subject to substantial erosion. | |