| Description | Spatial | Attributes |
Water bodies greater then 20FT in width for all of Prince George's County, Maryland
This coverage contains the drainage area where the width of the identified feature is 20 feet or more as photointerpreted from aerial photography. All lakes and ponds with a visible and distinct shoreline and having an aerial coverage greater than 20,000 square feet will be captured as polygons. The shoreline for these features is based on the water surface elevation when the aerial photography was taken and may not represent the normal pool elevation for the feature. The water surface elevation will be graphically labeled at or near the centroid of the feature. Areas of standing water, which may or may not be interspersed with areas of vegetation and which do not have a visible water impoundment structure will be outlined and labeled as ASTANDING WATER.@ RIVERS AND STREAMS: Bodies of water with an average width greater than or equal to 20 feet at ground scale will be captured as double line and stored with both polygon and line attributes. Streams with an average width of less than twenty feet will be shown as a single line and stored as an attributed line. MAJOR CULVERTS AND DAMS: Culverts greater than 50 feet in length and which carry rivers or streams under roads or railroads will be captured as a straight line connecting the apparent points where the stream or river enters and exits the culvert. Concrete structures such as head walls, wingwalls, and/or end sections will be shown if they are greater than 50 feet in length. Man made barriers erected across a stream to prevent or regulate the flow of water will be captured and labeled as ADAM.@ MAN MADE DRAINAGE FEATURES: Man made drainage basins, or reservoirs, are designed to store water runoff in order to recharge the ground water supply. These basins will be captured as linear features and labeled as ARESERVOIR@ only when visible from the photography, are greater than 10,000 square feet in aerial coverage, and are not bounded by fencing or other linear features. Man made drainage channels will be shown if they are greater than 200 feet in length and if visible on the aerial photography. All other hydrologic features not expressly described in these specifications will be connected by straight lines during the graphic workstation editing phase. This will be done in order to maintain a continuous network. Layer was created by ASI, Inc.