Natural Conservation Areas

Natural conservation areas were created by clipping artificial pathways (generally, areas that correspond to major rivers) and intermittent and perennial stream features from the National Hydrography Dataset (NHD) flowline feature class to the Hanover County boundary. Intermittent NHD features that did not intersect the FEMA floodplain layer were deleted from the dataset. These final flowlines were then buffered by 100 feet. NHD water body features were also buffered by 100 feet. Features from the buffered water body layer were deleted if they did not intersect the buffered flowlines or the FEMA floodplain layer. Next, the buffered NHD flowlines, the FEMA floodplain layer, and the buffered water body polygons were all merged into one polygon feature class. The geoprocessing tool 'multipart to singlepart' was then run on the polygons to separate multi-part features into distinct regions. Next, the geoprocessing tool 'simplify by straight lines and circular arcs' was run on the polygon layer to reduce the number of feature vertices and improve performance. Finally, any polygons overlaying developed areas were removed from the dataset by erasing the portion of the region within the property boundary of the developed parcel.