MANNINGS N VALUES ASSICITED WITH LANDUSE LAYER AND FLOODPLAIN INUNDATION MODELING USING ArcGIS _____

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MANNINGS N VALUES ASSICITED WITH LANDUSE LAYER
AND FLOODPLAIN INUNDATION MODELING USING
ArcGIS________CASE STUDY LAKE DARDANELLE,
ARKANSAS

• GIS For Water Resources Fall 2004
• By Kinagoto Nanadoum

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• The advent of ArcGIS created an opportunity to
  design a new way of representing water resources
  data
• _____________
• Landuse is used the generate Mannings n values
  in HEC-RAS Model

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• DATA USED
• - DEM
• - DAMS
• - LANDUSED
• - STREAMS
• - STREAM GAGES
• SOURCE USGS.GOV

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• USGS 07258000 Arkansas River at Dardanelle, AR
• Pope County, ArkansasHydrologic Unit Code
  11110203 Latitude  3513'32.82", Longitude 
  9308'56.19" NAD83Drainage area 153,670
   square milesGage datum 280.16 feet above sea lev
  el NGVD29

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• RESULTS
• June 16 1995 Streamflow
• Gage datum 280.16 feet above sea level NGVD29
• h 33.38 ft.
• Water Surface Elevation 280.16  33.38
  313.57 ft
• HEC-RAS Results 321.35 ft
• Difference 7.78 ft

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• 2. Feb. 19, 1938 Streamflow
• Gage datum 280.16 feet above sea level NGVD29
• h 29.55 ft.
• Water Surface Elevation 280.16  29.55
  309.71 ft
• HEC-RAS Results 326.33 ft
• Difference 16.62 ft.

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• CONCLUSION
• Differences exist
• Need more run through numerous site to
• draw conclusions.
• 3. Adjust Mannings n value et test the
  sensitivity