View In:   Map Viewer

The selected HU12 polygons received an estimated water surface elevation in feet above NAVD88 from the Coastal_Profile polyline. This was done by generating centroids for the HU12 polygons and snapping the centroid points to the closest location along the Coastal_Profile polyline layer. These snapped centroid points were assigned a station measurement value in feet along the Coastal_Profile line. This station value could then be used to derive an estimated Water Surface Elevation (WSE) value in feet above NAVD88 for the January and March 2018 storm events as well as an estimated USGS stillwater elevation. The HUC12 centroids with assigned WSE values were joined back to the HU12 polygon attribute table. The WSE fields for each storm event and USGS stillwater are documented in the metadata for this layer. The WSE fields were used to delineate inundation polygons inside each HU12. This was done by creating a raster surface from the WSE fields and determining where the WSE rasters were greater than or equal to the lidar digital elevation model (DEM). The process produces estimated inundation surface raster data sets that can then be converted to inundation polygon layers for cartographic smoothing and generalization.