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Hydrograph
Weather Forecast Office Philadelphia/Mount Holly, NJ
Middle Atlantic River Forecast Center
Hydrograph
River at a Glance
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About this graph
Tabular Data (UTC)
Tabular Data (EST)
Datum: Not Available
Metadata
NOTE:
Please refer to our
Coastal Hazard Message
for specific information regarding Coastal Flood Watches, Warnings and Advisories. Flood impacts are based on long-term averages. Actual impacts from any tidal flooding event may vary due to factors such as rainfall, wave action, and the number of tide cycles during which there is an onshore flow. During tropical cyclones, please refer
here
for additional storm surge information.
NOTE: During a Tropical Storm or Hurricane Watch or Warning, inundation mapping provided by the
National Hurricane Center
reflects a plausible worst case scenario. The experimental forecast above is the total water forecast that is expected to occur.
NOTE:
Forecasts for the Delaware Bay at Reedy Point (IN MLLW) are issued routinely year-round.
Vertical Datum references a tidal datum (MLLW)...for more information see
Tides and Currents
.
Default Hydrograph
Scale to Flood Categories
Return to Area Map
Flood Categories (in feet)
Major Flood Stage:
9.2
Moderate Flood Stage:
8.2
Flood Stage:
7.2
Action Stage:
0
Low Stage (in feet):
-2
Historic Crests
(1) 9.24 ft on 04/16/2011
(2) 9.19 ft on 12/21/2012
(3) 9.10 ft on 10/30/2012
(4) 8.88 ft on 10/25/1980
(5) 8.66 ft on 09/19/2003
Show More Historic Crests
(P)
: Preliminary values subject to further review.
Recent Crests
(1) 8.62 ft on 09/10/2018
(2) 8.25 ft on 05/01/2014
(3) 9.19 ft on 12/21/2012
(4) 9.10 ft on 10/30/2012
(5) 9.24 ft on 04/16/2011
Show More Recent Crests
(P)
: Preliminary values subject to further review.
Low Water Records
(1) -4.01 ft on 04/07/1982
(2) -3.83 ft on 11/21/1989
(3) -3.76 ft on 03/02/2018
(4) -3.60 ft on 03/08/1986
(5) -3.54 ft on 02/25/1990
Show More Low Water Records
Zoom Level:16
Legend
FEMA Layer
Gauge Location
Disclaimer
Latitude/Longitude Disclaimer: The gauge location shown in the above map is the approximate location based on the latitude/longitude coordinates provided to the NWS by the gauge owner.
Flood Impacts & Photos
If you notice any errors in the below information, please contact our
Webmaster
9.24
(Mean Lower Low Water (MLLW)) The level reached on April 16, 2011.
9.2
(MLLW) MAJOR FLOODING. At this level, widespread roadway flooding begins near the bay, the river and the tidal tributaries in New Castle County DE and Salem County NJ. Vulnerable homes and businesses may be damaged as water levels rise further above this threshold. Numerous roads become impassable and some neighborhoods may be isolated. The flood waters become a danger to anyone who attempts to cross on foot or in a vehicle.
8.2
(MLLW) MODERATE FLOODING. At this level, additional roadways near the bay, the river and the tidal tributaries in New Castle County DE and Salem County NJ begin to flood. Lives may be at risk when people put themselves in harm's way. Some damage to vulnerable structures may begin to occur. COASTAL FLOOD WARNING LEVEL.
7.8
(MLLW) Flooding begins along East 12th Street and along the south bank of the Christina River in Wilmington DE. Flooding begins where the Red Clay Creek, the White Clay Creek and the Christina River meet. The area is just to the west and northwest of the New Castle Airport and it includes the communities of Christiana, Glenville and Stanton DE. Flooding begins along the Appoquinimink River in Odessa DE. Flooding begins along NJ Route 49, Quinton-Alloway Road and Sickler Street in Quinton Township NJ.
7.6
(MLLW) Flooding begins along Oldmans Creek at US Route 130 and near Pedrickton NJ. Flooding begins in Penns Grove and Carneys Point NJ. Flooding begins along Riviera Drive and Hook Road in Pennsville Township NJ. Flooding begins along Pointers-Auburn Road in Mannington Township NJ. Flooding begins along NJ Route 45 at the Salem River. Flooding begins along Sinnicksons Landing Road and South Locust Avenue in Elsinboro Township NJ. Flooding begins along Beasley Neck Road in Lower Alloways Township NJ.
7.5
(MLLW) COASTAL FLOOD ADVISORY LEVEL.
7.4
(MLLW) Flooding begins in New Castle DE along the Strand and in the Dobbinsville section. Flooding begins along the section of DE Route 9 to the south of New Castle DE and around the approaches to the DE Route 9 bridge over the Red Lion Creek. Flooding begins in Delaware City DE including the area around the 5th Street bridge. Flooding begins in Port Penn, Augustine Beach and Bay View Beach DE. Flooding begins around the approaches to the DE Route 9 bridge over the Appoquinimink River.
7.2
(MLLW) MINOR FLOODING.
About This Location
Latitude: 39.551389° N, Longitude: 75.567778° W, Horizontal Datum: NAD83/WGS84
River Stage
Reference Frame
Gauge Height
Flood Stage
Uses
NWS stage
0 ft
7.2 ft
Interpreting hydrographs and NWS watch, warnings, and forecasts, and inundation maps
Vertical Datum
Elevation
(gauge height = 0)
Elevation
(gauge height = flood stage)
Elevation information source
NAVD88
-2.97
4.23
Survey grade GPS equipment, FEMA flood plain maps, newer USGS topographic maps
NGVD 29
Not Available
Not Available
Older USGS topographic maps, NGVD29 benchmarks
MSL
Not Available
Not Available
Older USGS topographic maps, MSL benchmarks
Other
-2.87
1.36
NAVD88 to MHHW conversion from NOAA Vertical Datum Transformation (VDatum)
Additional Information
All gage data is referenced in MLLW. During winter months, cold and ice may result in inaccurate real-time stages. Adjustments or deletions of this data can only be done after detailed analysis.
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The National Weather Service prepares its forecasts and other services in collaboration with agencies like the US Geological Survey, US Bureau of Reclamation, US Army Corps of Engineers, Natural Resource Conservation Service, National Park Service, ALERT Users Group, Bureau of Indian Affairs, and many state and local emergency managers across the country. For details,
please click here
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NWS Information
National Weather Service
Philadelphia/Mount Holly Weather Forecast Office
732 Woodlane Road
Mount Holly, NJ 08060-9615
(609) 261-6600
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Page last modified: 30-Oct-2020 4:10 PM
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