Geospatial datasets and hydraulic model for flood-inundation maps for the Schoharie Creek in North Blenheim, NY

Digital flood-inundation maps for a 2.4-mile reach of the Schoharie Creek in North Blenheim, New York, were created by the U.S. Geological Survey (USGS) in cooperation with the New York Power Authority. The flood-inundation maps, which can be accessed through the USGS Flood Inundation Mapping Science web site at https://fim.wim.usgs.gov/fim/, depict estimates of the areal extent and depth of flooding corresponding to selected water levels (stages) at the USGS streamgage on the Schoharie Creek near North Blenheim, NY (station number 01350212). Flood profiles were computed for the stream reach by means of a two-dimensional implicit finite volume hydraulic model. The model was calibrated using the active (as of April, 2021) stage-discharge ratings at two USGS streamgages on the Schoharie Creek (Schoharie Creek near North Blenheim, NY [01350212] and Schoharie Creek at North Blenheim, NY [01350180]) and documented high-water marks in the study reach from the floods of August 28, 2011, January 19, 1996, and April 4, 1987. 

The hydraulic model was used to compute 13 water-surface profiles for flood stages at 1-foot (ft) intervals referenced to the streamgage datum and ranging from 14 ft, or near bankfull, to 26 ft, which is the highest whole-foot-increment on the stage-discharge rating for the streamgage. The simulated water-surface profiles were then combined with a geographic information system digital elevation model (derived from light detection and ranging data having a 0.52-ft vertical accuracy and 3.3-ft horizontal resolution) to delineate the area flooded at each stage.

This data release contains five child items: (1) the field survey points used in model development; (2) the hydraulic model used to develop the inundation maps, and the (3) depth grids, (4) inundation polygons, and (5) water surface elevation grids from the model output.