Warning: Javascript must be enabled to use all the features on this page!

Page Loading - Please Wait...

Click to hideNews Bulletins
* IMPORTANT: Next Generation Station Page

USGS 01387450 Mahwah River near Suffern NY


Click to hidestation-specific text
Funding for this site is provided by:



LOCATION.--Lat 41°08'28", long 74°06'58" referenced to North American Datum of 1983, Ramapo Township, Rockland County, NY, Hydrologic Unit 02030103, on left bank 13 ft upstream from bridge on U.S. Route 202, 2.5 mi northeast of Suffern, and 4.8 mi upstream from mouth.
DRAINAGE AREA.--12.3 mi2.
PERIOD OF RECORD.--Continuous-record discharge station, water years 1959-95, 2006 to current year. Annual maximum gage, water years 1996 to 2005.
REVISED RECORDS.--WDR NY-79-1:1977(P). WDR NY-87-1:1986. WRD US-2011: 2001(M), 2005(M), 2006(M), 2007(M), 2008(M), 2010(M).
GAGE.--Water-stage recorder with telemetry. Datum of gage is 321.57 ft above NGVD of 1929. Prior to Nov 18, 1976, water-stage recorder at site on right bank, 13 ft downstream, at present datum.
REMARKS.--Records fair, except for estimated discharges, which are poor. Occasional regulation at low flow due to unknown source. Pumping from wells upstream of gage may affect flow past gage. Discharges above 2,200 ft3/s from rating curve extension on basis of contracted-opening and flow-over-road computations.
EXTREMES FOR PERIOD OF RECORD.--Maximum discharge, 3,700 ft3/s, Aug 28, 2011, gage height, 10.66 ft, from rating curve extended above 2,200 ft3/s on basis of contracted-opening and flow-over-road computations; minimum discharge, 0.05 ft3/s, Oct 20, 1970, result of temporary pumping from gage pool.

Peak Flood Chart

Gage Photo

National Weather Service flood stage for this gage is 4.0 ft.

Rain gage data is available from this location at this link.

This station managed by the New Jersey Water Science Center.

Available Parameters Available Period
All 2 Available Parameters for this site
00060 Discharge 1989-10-31  2019-07-22
00065 Gage height 2007-10-01  2019-07-22

Graph w/ stats
Graph w/o stats
Graph w/ (up to 3) parms
Days  (7)

  -- or --
Begin date

End date

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

Discharge, cubic feet per second

Most recent instantaneous value: 5.60 07-22-2019   07:30 EDT
Graph of

Add up to 2 more sites and replot for "Discharge, cubic feet per second"

 Add site numbers

Create presentation-quality / stand-alone graph.   Subscribe to WaterAlert      

Daily discharge, cubic feet per second -- statistics for Jul 22 based on 49 water years of record more
Median Most Recent
Value Jul 22
Mean 75th
0.88 2.3 4.1 5.60 7.0 9.5 23.0

Gage height, feet

Most recent instantaneous value: 1.59 07-22-2019   07:30 EDT
Graph of

Add up to 2 more sites and replot for "Gage height, feet"

 Add site numbers

Create presentation-quality / stand-alone graph.   Subscribe to WaterAlert