Silver Jackets Project - Chattahoochee River in Helen, Georgia (General)

The purpose of this project was to complete Flood Forecast Inundation Mapping (FFIM) for a reach of the Chattahoochee River through the city of Helen, Georgia. The FFIM project submittals include a geo-referenced HEC-RAS hydraulic model and geo-referenced inundation polygons and depth grids. In addition to this main data submittal, base and supplemental data are required to accompany the mapping products for proper documentation and implementation of the flood mapping outputs. The reach was modeled with 1-D, steady flow hydraulic modeling software, utilizing geo-referenced stream parameters and a 2-m LiDAR dataset. These data will be provided to the National Weather Service (NWS) of the National Oceanic and Atmospheric Association (NOAA) for potential implementation onto the Advanced Hydrologic Prediction Service (AHPS) web interface and connected with the river forecast for HDCG1.

The project area is located in the city of Helen, Georgia, which lies in north-central White County and the Chattahoochee River Watershed. The county is bordered by Towns County to the north, Union and Lumpkin Counties to the west, Habersham County to the east, and Hall County to the south. The project area encompasses an approximate 5.25-mile reach of the Chattahoochee River, beginning at a location approximately 7,600 feet upstream of the Helen, GA corporate limits, and ending at a location approximately 5,800 feet downstream of the Helen, GA corporate limits.

NWSLID: HDCG1
Latitude: 34.700833° N, Longitude: 83.729444° W, Horizontal Datum: NAD83/WGS84