SURFACE-WATER RECORDS
LOCATION.--Lat 40°19'11", long 74°06'56" referenced to North American Datum of 1983, Colts Neck Township, Monmouth County, NJ, Hydrologic Unit 02030104, on left bank 50 ft upstream from spillway at Swimming River Reservoir, 1,000 ft upstream of bridge on Swimming River Road (County Route 50), 3.3 mi southwest of Red Bank, and 4.8 mi upstream from mouth.
DRAINAGE AREA.--49.2 mi².
PERIOD OF RECORD.--Continuous-record discharge station, August 1922 to current year.
REVISED RECORDS.--WSP 891: 1939. WDR NJ-83-1: Drainage area. WDR NJ-90-1: 1989
GAGE.--Water-stage recorder with telemetry above concrete dam. Datum of gage is 30.00 ft above NGVD of 1929. Prior to Jan 19, 1962, at site 800 ft upstream at datum 17.67 ft lower. Jan 19 to Mar 30, 1962, non-recording gage, 700 ft upstream at datum 13.87 ft lower.
REMARKS.--Records fair, except for estimated discharges and discharges less than 5 ft³/s, which are poor. Records given herein represent flow over spillway and flow or leakage through blowoff gates. Flow regulated by diversions from Swimming River Reservoir for municipal supply. Reservoir used for storage and water diversion by New Jersey-American Water Company. Reservoir enlarged and dam raised in 1962. Discharges above 1,100 ft³/s from rating curve extension on basis of weir formula.
EXTREMES FOR PERIOD OF RECORD.--Maximum discharge, 8,910 ft³/s, from rating curve extended above 1,100 ft³/s on basis of weir formula, Oct 27, 1943, gage height, 8.96 ft, site and datum then in use; minimum discharge, 0.00 ft³/s, many days.
EXTREMES OUTSIDE PERIOD OF RECORD.--Flood of July 1919 reached a stage of 7.84 ft (site and datum then in use; from floodmark), discharge, approximately 11,800 ft³/s.

WATER-QUALITY RECORDS
PERIOD OF RECORD.--Water years 1923-24, 1952, 1960-72, 1974-81, 2007.

Peak Flood Chart

National Weather Service flood stage for this gage is 7 ft.