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Posted at 04:25 PM ET, 10/31/2012

Alexandria, Georgetown brace for Potomac river flooding


Hydrograph for Georgetown showing past river levels in blue and forecast rivers levels in purple. (NOAA)
As the runoff from Sandy’s prolific rains washes down the Potomac river, rounds of coastal flooding in Alexandria and Georgetown will last into Thursday.

A coastal flood warning is in effect through 2 p.m. Thursday, spanning the next 2 high tide cycles. Water levels of 2 to 3 feet above normal tide are expected, which will result in moderate flooding the National Weather Service says.

Here are the next two high tides:

WASHINGTON CHANNEL...9:54 PM AND 10:26 AM...

ALEXANDRIA...10:12 PM AND 10:44 AM...

The last comparable flood events occurred in this area occurred on May 18-19, 2011 and April 18, 2011. In the April event , the Georgetown waterfront was evacuated and some businesses flooded . Levels rose three feet above flood stage, but the floodgates had not been engaged exacerbating related problems.

The National Weather Service forecasts levels to be slightly less than both of these events. For example, in Georgetown, the level is forecast to reach 7.6 feet (1.6 feet above flood stage), whereas it reached 9 feet (3 feet above flood stage) on April 18, 2011 and 8.5 feet (2.5 feet above flood stage) May 18-19.

Last night, minor flooding was reported in both Georgetown and Old Town. In Georgetown, the level reached 7.6 feet, the same level forecast tonight.

Further upstream, a flood warning continues for the Monocacy river near Frederick through this evening although levels are dropping. The National Weather Service reported the following flooding was occurring at of 3:23 p.m.:

MUCH OF PINECLIFF PARK AND RIVERMIST PARK IN FREDERICK ARE FLOODED. BUCKEYSTOWN COMMUNITY PARK IS ALSO FLOODED WITH WATER APPROACHING THE PARKING LOT. WATERS ARE ALSO APPROACHING THE FREDERICK CITY WASTEWATER TREATMENT PLANT AND THE BALLENGER CREEK WASTEWATER TREATMENT PLANT. SIGNIFICANT BACKWATER FLOODING IS OCCURRING. SEVERAL ROADS WILL BE CLOSED ALONG THE RIVER AND ADJOINING CREEKS.

Also, a flood warning is in effect for the upper Potomac River at Point of Rocks, Md. through Thursday morning. As of 3:09 p.m., the following flooding was occurring according to the NWS:

FLOODING OF AN AGRICULTURAL FIELD ADJACENT TO THE MCKIMMEY BOAT RAMP IS OCCURRING. ABOUT HALF THE PARKING LOT OF THE POINT OF ROCKS BOAT RAMP IS ALSO FLOODED

Levels are forecast to drop overnight.

By  |  04:25 PM ET, 10/31/2012

Categories:  Latest, Floods

 
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