Inundation Polygons
Format: ESRI shapefile polygons (WGS84 Web Mercator
(Auxiliary Sphere) EPSG: 3857).

Items: Inundation polygons for the flood stage elevations running from action stage through the 
record flood. (Note: elevations based on NAVD88 and flow based on cfs)

Notes:
1.   Inundation polygons must be created at equal intervals.
Intervals may be sized according to site characteristics and may range from 0.1 ft to 1.0 ft or an 
equivalent flow range in cfs.
2.   Inundation polygons should use the following naming convention for stage locations 
elev_{feet}_{tenth}.shp or flow_{cfs}.shp for flow locations. (Note: locations cannot present both 
stage and flow data)
a.   Example for stage: An inundation layer at 78.3 feet
NAVD88 the file would be named: elev_78_3.shp
b.   Example for flow: An inundation layer at 34,000 cfs the file would be named: flow_34000.shp
3.   Inundation polygons must pass the QC standards provided by the NWS (see Partner QA Checklist).
4.   The presence of and hydraulic effect of bridges should be reflected in the inundation polygons 
at each depth interval. If the low chord of the bridge is not inundated, then the polygons should 
be clipped adjacent to the upstream and downstream side of the bridge to show that the bridge 
decking is dry. If all or part of a bridge decking is inundated, then all or part of the bridge 
decking should be
shown as covered by the inundation polygon.