Alexandria Flood Category Change

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Flood Categories changed on the Tidal Potomac River at Alexandria on August 15th

Effective on Wednesday, August 15th, 2018, some of the flood categories on the Tidal Potomac River at Alexandria were changed. This change is in response to recent analysis conducted by the City of Alexandria and is intended to better align impacts with the flood categories.

The NWS identifier for this gauge is AXTV2, and the gauge is operated by the United States Geological Survey (USGS).

The minor flood level at this location was raised from 3.1 feet to 3.3 feet. While only a small adjustment, this revision will allow for Coastal Flood Advisories to be issued only when nuisance-level impacts are observed, not at the first sign of water. Interests in the area should be advised that it is likely that some small amounts of water will be observed within the range between "action stage" of 2.5 feet and the new minor flood level of 3.3 feet.

The moderate flood level at this location was lowered from 4.5 feet to 4.2 feet. Collaboration with the City of Alexandria helped determine that, if not mitigated, structural flooding (which meets the moderate flood definition) occurs at 4.2 feet.

The following table summarizes the categories and changes:

Category	Current Level	New Level (8/15/2018)	Status
Action Stage	2.5 feet	2.5 feet	No change
Minor Flood	3.1 feet	3.3 feet	Raised 0.2
Moderate Flood	4.5 feet	4.2 feet	Lowered 0.3
Major Flood	6.6 feet	6.6 feet	No change

Category

Current Level

New Level
(8/15/2018)

Status

Action Stage

2.5 feet

No change

Minor Flood

3.1 feet

3.3 feet

Raised 0.2

Moderate Flood