24' - The Potomac River and C&O Canal form a single body of water upstream of Dalecarlia Reservoir. A portion of Canal Road begins to flood near Chain Bridge. Flooding and backwater cover much of lower Georgetown south of the Canal, and the Rock Creek Parkway south of M Street NW. The George Washington Parkway is flooded south of Spout Run in Arlington. Floodwaters reach Constitution Avenue near the Lincoln Memorial at the low spot on Henry Bacon Drive.
20' - Significant flooding is occurring in lower Georgetown, with all of Water Street NW and K Street NW flooded west of Rock Creek. Floodwaters reach about halfway up Thomas Jefferson Street NW in Georgetown. Numerous buildings are flooded. Rock Creek Parkway is flooded south of Virginia Avenue NW, and portions of the Kennedy Center are flooded. Ohio Drive is flooded in the vicinity of the Lincoln Memorial.
18' - Floodwaters reach the top of the protection of the floodgates at Washington Harbour.
17.5' - All of Water Street NW and K Street NW are flooded between the Key Bridge and Rock Creek, with numerous roads and buildings in lower Georgetown affected. Multiple portions of the George Washington Parkway are flooded south of Spout Run. Rock Creek Parkway is flooded south of the Watergate Complex. Ohio Drive is flooded in the vicinity of Memorial Bridge.
16.5' - A portion of Rock Creek and Potomac Parkway is flooded near the Kennedy Center. Much of lower Georgetown is flooded, including Water Street and K Street between 33rd and 30th, and all adjacent unprotected structures. Portions of the George Washington Parkway are also flooded between Spout Run Parkway and the Memorial Bridge.
15.5' - A portion of Rock Creek and Potomac Parkway near the Kennedy Center begins to flood. A significant portion of lower Georgetown is flooded, including K Street between Wisconsin Avenue and 30th Street NW. Portions of Ohio Drive near the Lincoln Memorial also are flooded. On the Virginia side of the river, portions of the George Washington Memorial Parkway are flooded between Key Bridge and Memorial Bridge.
14.5' - Portions of the George Washington Parkway begin to flood between the Roosevelt Island access point and the Memorial Bridge.
13.5' - K Street is flooded between Wisconsin Avenue and 30th Street. Backwater flooding along Rock Creek is affecting buildings between the C&O Canal and the Potomac.
12' - Floodwaters reach Georgetown Waterfront Park at the foot of Wisconsin Avenue in Georgetown. Low spots on Ohio Drive SW near the Memorial Bridge begin to flood.
11' - The river reaches a height in which usual high and low tides are no longer observed. From this point the river will rise until crest and then fall. Overflow of the C&O Canal may cause water to flow down the walkways near the Georgetown Visitors Center. Access roads in the vicinity of the Fletchers Boathouse are flooded. Floodwaters approach portions of the Capital Crescent Trail.
10' - Backwater flooding threatens structures along Rock Creek south of K Street. Water reaches the parking area at Fletcher's Boathouse. The Washington Canoe Club and Potomac Boat Club buildings are flooded. Water also reaches the parking lot and access road for Roosevelt Island.
8' - Backwater flooding of Rock Creek in Georgetown begins at this level.
7.5' - Washington Harbour will begin to flood if floodgates are not in place. More than a third of Roosevelt Island is covered by water.
7' - Water begins to cover the boardwalk at Washington Harbour. Downstream, water is out of the banks in a few low spots between Fletcher's Boathouse and Interstate 66.
6.5' - During some events, water may begin to bubble up through storm drains near Washington Harbour.
6' - Low lying areas near Fletcher's Boathouse begin to flood. Water also begins to overflow the banks near the mouth of Rock Creek. Portions of the Swamp Trail on Roosevelt Island are flooded.