A New Flood Emergency

A new flash flood emergency in Louisiana’s St. Tammany Parish as a lock and dam on the Pearl River Diversion Canal is about to fail. Here is the area affected:

An 11 foot flood wave is expected downstream if it fails.

BULLETIN – EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE NEW ORLEANS LA
304 PM CDT SAT SEP 1 2012

THE NATIONAL WEATHER SERVICE IN NEW ORLEANS HAS ISSUED A

* FLASH FLOOD WARNING FOR…
CENTRAL ST. TAMMANY PARISH IN SOUTHEAST LOUISIANA…

* UNTIL 900 PM CDT

* AT 251 PM CDT…ST TAMMANY PARISH OFFICE OF EMERGENCY MANAGEMENT
REPORTED THAT THE PEARL RIVER DIVERSION CANAL LOCK AND DAM NUMBER
TWO IS ABOUT TO FAIL. HEAVY SCOUR IS TAKING PLACE ALONG SIDE THE
RELIEF SILL. THE CURRENT STAGE IS 18.5 FEET AT BUSH.

THIS IS A FLASH FLOOD EMERGENCY FOR ALL RESIDENTS AND INTEREST
DOWNSTREAM OF PEARL RIVER LOCK AND DAM #2 NEAR BUSH DOWNSTREAM TO
HIGHWAY 36 AT HICKORY.

More information…

THE FOLLOWING ARE SOME MORE DETAILS REGARDING THE FLASH FLOOD
EMERGENCY DECLARED FOR THE PEARL RIVER DIVERSION CANAL.

IF AND WHEN THE STRUCTURE FAILS…THE ESTIMATED INITIAL FLOOD WAVE
IS EXPECTED TO BE AROUND 11 FEET.

THE CAMPGROUND ONE-HALF MILE DOWNSTREAM OF THE LOCK STRUCTURE IS
ESTIMATED TO GET ABOUT 10 FEET OF FLOOD WAVE. THIS CAMPGROUND AND
NEARBY RESIDENTS HAVE BEEN EVACUATED.

TRAVEL TIME OF THE FLOOD WAVE TO LOCK AND DAM NUMBER ONE…11 MILES
DOWNSTREAM…IS ESTIMATED TO BE ONE HOUR WITH A FLOOD WAVE ESTIMATED
TO BE 5.5 FEET. THIS STRUCTURE WILL OFFER SOME RESISTANCE TO FURTHER
TRAVEL DOWNSTREAM.

IF THE WAVE SHOULD CONTINUE BEYOND LOCK AND DAM NUMBER ONE…
AT INTERSTATE 59 AT THE PEARL RIVER…18 MILES DOWNSTREAM…A FLOOD
WAVE OF AN ADDITIONAL 2.5 FEET OF WATER LEVEL WOULD REACH THAT POINT
BETWEEN 2 AND 4 HOURS OF PASSING LOCK AND DAM NUMBER ONE.

THESE HEIGHTS AND TIMES ARE ESTIMATES AS COORDINATED WITH THE LOWER
MISSISSIPPI RIVER FORECAST CENTER. AT THIS TIME…THE STRUCTURE IS
STILL INTACT AND RELIEF VALVES HAVE BEEN OPENED TO LESSEN SOME
PRESSURE ON THE STRUCTURE.

PERSONS AND INTERESTS IN THIS WARNED AREA SHOULD NOT RETURN UNTIL
THE LOCAL OFFICIALS GIVE THE ALL CLEAR. THIS REMAINS A DANGEROUS
SITUATION WITHIN A LIMITED AREA NEAR AND DOWNSTREAM OF THE PEARL
RIVER DIVERSION CANAL BELOW LOCK AND DAM NUMBER TWO.

Category: Severe Weather