Friday, March 11, 2011

River Flood Update

Two soaking rain events over the past six days have depsosited over three inches of rainfall in the watershed area causing most streams to rise to bank full levels.  Prior to this week, melting snowfall in mid-February combined with late February rainfall primed soils in the Ohio Valley for river flooding.  River flooding is different from flash flooding in that it develops slowly and only affects floodplain near stream confluences with the Ohio River.  Because of its low-lying elevation, Powhatan Point routinely experiences river flooding in areas close to the mouth of Captina Creek.  According to the hydrograph issued by the NWS at 8 am this morning the Ohio River is expected to crest at Powhatan Point below major flood stage at 40.9ft (flood stage 37ft.).   At a level of 40 ft. the SR 7 bridge crossing Captina Creek begins to submerge disrupting a major travel artery along the Ohio River.  *If the current predicted crest holds, this would be the fifth highest river crest in recorded history at Powhatan Point.  Monitor updated forecasts on the crest by clicking on the NWS advanced hydrologic prediction link on the right side of the page.

*Edit:  After doing a little research on record crests of the Ohio River at Powhatan, I began to realize the NWS top five on the advanced hydrologic prediction page for Powhatan is not accurate. For a better perspective on the matter click Wheeling Hydrograph Data and scroll down on the left side of the page.

  The latest predicted crest for the Ohio River at Powhatan Point
is 40.9 ft. just below major flood status but nowhere close
to the all-time record set in the great 1936 flood. 
*Interestingly, the next four highest crests after 1936 have
all occurred in the last fifteen years.  (See edit above)
Note: kcfs=kilo cubic feet/second!!

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