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USGS 01387500 Ramapo River near Mahwah NJ


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During winter months, cold and ice may result in inaccurate real-time gage height and streamflow data. Adjustments or deletions of this data can only be done after detailed analysis.



LOCATION.--Lat 41°05'53", long 74°09'46" referenced to North American Datum of 1983, Mahwah Township, Bergen County, NJ, Hydrologic Unit 02030103, on left bank 350 ft downstream from State Highway 17, 0.6 mi downstream from Mahwah River, 1.0 mi west of Mahwah, and 1.2 mi downstream of New York-New Jersey State line.
DRAINAGE AREA.--120 mi².
PERIOD OF RECORD.--Continuous-record discharge station October 1902 to December 1906, September 1922 to current year. October 1902 to February 1905 monthly discharge only, published in WSP 1302. Figures of daily discharge Feb 10, 1903 to Dec 31, 1904, published in WSP 97 and 125, are unreliable and should not be used. Gage-height records for 1903-14 are contained in reports of the National Weather Service.
REVISIONS HISTORY.--WSP 781: 1904(M). WSP 1031: 1938, 1940. WSP 1552: 1923(M), 1924, 1925-26(M), 1927-28, 1933, 1937. WRD-NJ 1971: 1968(M). WDR NJ-82-1: Drainage area. WDR-NJ-87-1: 1986. WDR US-2011: 1984(M), 1999(M), 2010(M). WDR US-2013: 2011.  On Jun 13, 2019, discharge below 5 ft³/s for the period of Jul 23, 1993 to Sep 2, 1993, was revised based on changes to the stage-discharge rating.
GAGE.--Water-stage recorder with telemetry. Datum of gage is 253.10 ft above NGVD of 1929. Prior to Dec 31, 1906, non-recording gage on former bridge at site 250 ft downstream at different datum. Sep 1, 1922 to Dec 23, 1936, water-stage recorder just below former bridge at present datum.
REMARKS.--Records good, except for estimated discharges, which are fair. Flow affected by diversion from United Water-New York well field upstream of gage (see 01387420). Occasional regulation from lakes and ponds upstream of gage.
EXTREMES FOR PERIOD OF RECORD.--Maximum discharge, 18,300 ft³/s, Aug 28, 2011, gage height, 15.77 ft; minimum discharge, 1.9 ft³/s, Aug 11, 1993.


PERIOD OF RECORD.--Water years 1963 to current year.
REMARKS.--Discrete water-quality data were collected as part of the New Jersey Ambient Surface-Water-Quality Monitoring Network.

Peak Flood Chart

Gage Photo

National Weather Service flood stage for this gage is 8.0 ft.

Forecasts for this gage are issued by the National Weather Service routinely year-round.
Forecast information is available here.

This station managed by the New Jersey Water Science Center.

Available Parameters Available Period
1981-10-01  2022-09-26
2007-10-01  2022-09-26


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Summary of all available data for this site
Instantaneous-data availability statement

Discharge, cubic feet per second

Most recent instantaneous value: 17.1 09-26-2022   06:00 EDT
Graph of  Discharge, cubic feet per second

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Daily discharge, cubic feet per second -- statistics for Sep 26 based on 103 water years of record more
Most Recent
Value Sep 26
Median Mean 75th
10.0 17.1 23 47 109 110 2080

Gage height, feet

Most recent instantaneous value: 2.56 09-26-2022   06:00 EDT
Graph of  Gage height, feet

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