Hydrography Centerlines. This dataset contains lines representing all perennial streams and the centerlines of rivers wider than 10 feet. The features are pointed in the direction of streamflow. Features were updated using NGA and USGS 30 centimeter aerial photos flown from March 26th through April 3rd, 2012 that encompass the entire County. Red-Green-Blue and Color Infrared were both used to capture, modify, and validate new and changed features.