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New Jersey FloodWatch

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Picture of flooding on the Duck River, Tennessee

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USGS IN YOUR STATE

USGS Water Science Centers are located in each state.

There is a USGS Water Science Center office in each State Washington Oregon California Idaho Nevada Montana Wyoming Utah Colorado Arizona New Mexico North Dakota South Dakota Nebraska Kansas Oklahoma Texas Minnesota Iowa Missouri Arkansas Louisiana Wisconsin Illinois Mississippi Michigan Indiana Ohio Kentucky Tennessee Alabama Pennsylvania West Virginia Georgia Florida Caribbean Alaska Hawaii New York Vermont New Hampshire Maine Massachusetts South Carolina North Carolina Rhode Island Virginia Connecticut New Jersey Maryland-Delaware-D.C.

Flood Magnitude and Frequency

Flood-frequency analysis provides information about the magnitude and frequency of selected flood discharges. Frequency commonly is expressed in terms of exceedance probability (a dimensionless number ranging from 0 to 1.0) or as a recurrence interval (the reciprocal of exceedance probability) in years (table 1). Flood-frequency information is important for defining flood-hazard areas; for managing floodplains; and for designing bridges, culverts, dams, levees, and other structures.


Table 1. Exceedance probabilities and associated recurrence intervals

Annual exceedance probability Recurrence interval (n-year flood)
0.6667 1.50
0.50 2.00
0.4292 2.33
0.20 5.00
0.10 10.00
0.04 25.00
0.02 50.00
0.01 100.00
0.005 200.00
0.002 500.00

Publications

  •  OFR 95-417: Flood magnitude and frequency of Hollow Brook at the culvert on New Jersey route 35, at Neptune Township, New Jersey
  •  OFR 95-323: Flood magnitude and frequency of Eightmile Branch tributary at the culvert on New Jersey route 72, at Stafford Township, New Jersey
  •  OFR 94-500: Flood magnitude and frequency of Chandlers Run at two sites, at Pennsauken Township, New Jersey
  •  OFR 94-499: Flood magnitude and frequency of Pochack Creek at two sites, at Pennsauken Township, New Jersey
  •  OFR 93-662: Flood magnitude and frequency of Delaware River tributary at the culvert on New Jersey Route 29, at Lambertville, New Jersey
  •  OFR 71-113: Extent and frequency of floods on Crosswicks Creek from New Egypt to Bordentown, New Jersey
  •  HA 104: Floods on Raritan and Millstone Rivers in Somerset County, New Jersey

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Page Last Modified: Monday, 14-Jan-2013 09:26:41 EST