PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE WILMINGTON OH
1216 PM EST THU DEC 27 2012

...FLOOD STAGE CHANGES TO OCCUR ON JANUARY 28 FOR RACCOON CREEK AT
GRANVILLE OH...

EFFECTIVE JANUARY 28, 2013...THE FLOOD STAGE AND MODERATE AND
MAJOR FLOOD CATEGORIES FOR THE RACCOON CREEK NEAR GRANVILLE, OHIO
WILL BE LOWERED BY SEVERAL FEET.

THE LOWERING WAS DUE IN PART TO AN ELEVATION CORRECTION BY THE
OHIO USGS...AS WELL AS CORRECTIONS BY THE NWS WITH REGARD TO
HISTORIC FLOODS AND IMPACTS IN THE AREA. 

THE RACCOON CREEK AT GRANVILLE IS ALSO PART OF A USGS INUNDATION
MAPPING EFFORT...IN WHICH MORE SPECIFIC FLOOD INUNDATION WAS USED
TO DETERMINE SPECIFIC FLOOD CATEGORIES.

THE USGS-CORRECTED CHANNEL BOTTOM ELEVATION AT THE GAGE IS 901.46
FEET...NAVD88 DATUM. THE PREVIOUS USGS CHANNEL BOTTOM ELEVATION
WAS 900.17 FEET...NAVD88 DATUM.

THE UPDATED FLOOD STAGE CHANGES ARE AS FOLLOWS:

ACTION STAGE: 10 FEET...NO CHANGE
FLOOD STAGE/MINOR FLOODING: 13 FEET...LOWERED FROM 17 FEET

MODERATE FLOODING/SOME INUNDATION OF CRITICAL STRUCTURES: 16
FEET...LOWERED FROM 20 FEET.

MAJOR FLOODING/SIGNIFICANT INUNDATION OF CRITICAL STRUCTURES:
17 FEET...LOWERED FROM 22 FEET. 

BECAUSE OF THE COMBINATION OF THESE CHANGES/CORRECTIONS...
EFFECTIVE ON JANUARY 28, 2013...FLOOD WARNINGS AND STATEMENTS WILL
REFERENCE THE NEW FLOOD CATEGORY LEVELS.

IT IS ESTIMATED THAT THE FLOOD OF RECORD FOR THE AREA WAS DURING
THE JANUARY 1959 FLOOD. BASED ON CURRENT ELEVATIONS AND HISTORIC
PHOTOS OF THAT SIGNIFICANT FLOOD...IT IS ESTIMATED THAT THIS FLOOD
WOULD REACH ROUGHLY 18 TO 18.5 FEET ON THE CURRENT GAGE NEAR GRANVILLE.

DUE TO THE VARIABLE TERRAIN NEAR THE GRANVILLE AREA...ROUGHLY 90
PERCENT OF GRANVILLE ITSELF IS WELL OUT OF THE FLOOD PLAIN. THE
CRITICAL STRUCTURES TO FLOOD AT THE HIGHER CREEK LEVELS ARE VERY
NEAR THE CREEK CHANNEL ITSELF.

IF YOU HAVE ANY QUESTIONS OR COMMENTS ON THIS CHANGE...PLEASE CONTACT:

JULIE DIAN-REED
SERVICE HYDROLOGIST
NATIONAL WEATHER SERVICE FORECAST OFFICE, WILMINGTON OH
1901 S. STATE ROUTE 134
WILMINGTON, OH 45177
937-383-0428


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