Description: The computed elevation to which floodwater is anticipated to rise during the base flood. Base Flood Elevations (BFEs) are shown on Flood Insurance Rate Maps (FIRMs) and on the flood profiles. The BFE is the regulatory requirement for the elevation or floodproofing of structures
Service Item Id: 6ba2ed4d5fe54d698b4ed133b4ac8aa3
Copyright Text: Roanoke County, FEMA (Federal Emergency Management Agency)
Description: There are two separate components to the NH Screening Coverage...1) Conservation Sites represent key areas of the landscape of protection and stewardship action because of the natural heritage resources and habitat they support. Conservation sites are polygons built around one or more rare plant or animal, or significant natural community or geological feature. Sites are designed to include the element and, where possible, its associated habitat, and buffer or other adjacent land thought necessary for the element's conservation. For rare aquatic species we define Stream Conservation Units (SCUs), which identify stream reaches that contain aquatic natural heritage resources, including upstream and downstream buffer and tributaries associated with this reach. There are almost 2000 terrestrial and SCU site records in the Conservation Sites coverage; these sites encompass all viable, recently-verified element occurrences documented in our databases. Conservation Sites and SCUs are given a biodiversity significance ranking based on the rarity, quality, and number of natural heritage resources they contain. Conservation Sites can be used to identify land management needs and protection priorities. They can also be used as a screening tool, to identify potential conflicts with development activities, and they can be used for proactive planning to ensure that development projects successfully avoid or enhance natural heritage resources.2) General Location Areas for Natural Heritage Resources represent the approximate locations of documented natural heritage resource occurrences that were not incorporated into Conservation Sites, either because they are poor quality, their location was not precisely identified, or they have not been reverified in over 20 years. These approximate locations are included in the Screening Coverage because they indicate areas with relatively high potential for natural heritage resource occurrences to be redocumented. Depending on the apparent suitability of local habitat, DCR-NH may recommend biological surveys when reviewing projects that intersect these locations. Some general location areas are represented by circular polygons of 0.5 mi. radius. Some are regular polygons. For these records, a review of recent aerial photography in conjunction with known habitat needs for the element identified potential habitat that might exist within the limits documented in the original occurrence.
Description: The data set was developed by the Virginia Division of Geology and Mineral Resources to depict areas of karst as defined by the presence of sinkholes. Sinkholes were identified from low-altitude stereoscopic aerial photo pairs and traced onto 1:24:000 paper topographic maps, from which they were table-digitized. This is the same data depicted at 1:250,000 scale in Division of Geology Mineral Resources Publications 44, 83, and 167. Field checking has revealed that many more sinkholes are present than are depicted in this dataset. Therefore, these data should serve as a general guide to areas of karst-related sinkhole development, and not as a true indication of the presence or absence of sinkholes at a particular location.
Service Item Id: 6ba2ed4d5fe54d698b4ed133b4ac8aa3
Copyright Text: Virginia Division of Geology and Mineral Resources
Department of Mines, Minerals and Energy
Hubbard, D. A., Jr., 1983, Selected Karst Features of the Northern Valley and Ridge Province, Virginia: Virginia Division of Mineral Resources Publication 44, 1:250,000-scale map.
Hubbard, D. A., Jr., 1988, Selected Karst Features of the Central Valley and Ridge Province, Virginia: Virginia Division of Mineral Resources Publication 83, 1:250,000-scale map.
Hubbard, D. A., Jr., 2001, Selected Karst Features of the Southern Valley and Ridge Province, Virginia: Virginia Division of Mineral Resources Publication 167, 1:250,000-scale map.
Description: This polygon feature was obtained from the United States Department of Agriculture. It is a polygon feature that inventories existing soil types.
Service Item Id: 6ba2ed4d5fe54d698b4ed133b4ac8aa3
Copyright Text: United States Department of Agriculture, GIS Services Staff, Roanoke County Communitt Development Staff.