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

Page Loading - Please Wait...

* We've detected you're using a mobile device. Find our Next Generation Station Page here.
Click to hideNews Bulletins
! We're replacing this page with a Next Generation Monitoring Location Page.
We're modernizing Water Data for the Nation delivery. Find out what this means for you. This page will be discontinued July 2023.

USGS 01405400 Manalapan Brook at Spotswood NJ


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



LOCATION.--Lat 40°23'22", long 74°23'26" referenced to North American Datum of 1983, Spotswood Borough, Middlesex County, NJ, Hydrologic Unit 02030105, on right bank upstream of DeVoe Lake Dam in Spotswood, 0.1 mi upstream from Cedar Brook, and 0.6 mi upstream from confluence with Matchaponix Brook.
DRAINAGE AREA.--40.7 mi2.
PERIOD OF RECORD.--Continuous-record discharge station, January 1957 to current year.
REVISED RECORDS.--WSP 1722:1957-60, WDR NJ-2005-1:1989(M), WDR-US-2006:2005(m).
GAGE.--Water-stage recorder with telemetry above concrete dam. Datum of gage is NGVD of 1929 (levels by Duhernal Water System). January 1957 to September 1966 at datum 17.72 ft higher.
REMARKS.--Records fair, except for estimated discharges, which are poor. Discharge given herein includes flow over dam and through sluice gates when open. Some regulation by Lake Manalapan, Helmetta Pond, and DeVoe Lake.
EXTREMES FOR PERIOD OF RECORD.--Maximum discharge, 6,550 ft3/s, estimated, includes estimated flow through sluice gates, Aug 28, 2011, gage height, 22.22 ft, from high-water mark; minimum discharge, 0.0 ft3/s, many days, undetermined amount of leakage through sluice gates when closed and lake level is below spillway crest.

Peak Flood Chart

Gage Photo

National Weather Service flood stage for this gage is 19 ft.

When heavy rain is forecast, gates in the dam are often opened to prevent flooding. This results in a sharp reduction of lake levels before a storm, and rises in lake levels after the storm. USGS records are corrected for this gate flow before publication.

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


  -- or --



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

Discharge, cubic feet per second

Most recent instantaneous value: 14.3 09-26-2022   05:15 EDT
Graph of  Discharge, cubic feet per second

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


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

See this graph on the Monitoring Location Pages

Gage height, feet

Most recent instantaneous value: 9.69 09-26-2022   05:15 EDT
Graph of  Gage height, feet

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


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

See this graph on the Monitoring Location Pages