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> Site Information
LOCATION.--Lat 41°27'40.4", long 74°45'31.6" referenced to North American Datum of 1983, Sullivan County, NY, Hydrologic Unit 02040104, on right bank 300 ft downstream from powerplant, 0.5 mi downstream from Bush Kill, and 2.8 mi upstream from mouth and Mongaup.
DRAINAGE AREA.--200 mi².
PERIOD OF RECORD.--August 1939 to March 1995, October 2013 to current year.
REVISIONS HISTORY.--WDR NY-71-1: 1970. WDR NY-81-1: 1980. WDR NY-82-1: Drainage area.
GAGE.--Water-stage recorder and crest-stage gage. Datum of gage is 625.05 ft above NGVD of 1929 (levels by Orange and Rockland Utilities, Inc.) and 623.49 ft above NAVD of 1988. Prior to July 6, 1956, water-stage recorders at sites 25 ft upstream on Rio tailrace and 200 ft upstream on natural channel, at datum 4.0 ft higher.
REMARKS.--Entire flow regulated by powerplant except for runoff from about 7 mi² of drainage area downstream from Rio Dam, and during periods of spill from Rio Reservoir. Flow also regulated by storage in Cliff Lake (station 01433200), Swinging Bridge Reservoir (station 01433000), and Toronto Reservoir (station 01433100) and small reservoirs upstream from station.
Water Years 2014-20: Records fair.
EXTREMES FOR PERIOD OF RECORD.--Maximum discharge, 16,100 ft³/s, Aug. 19, 1955, gage height, 11.22 ft, site and datum then in use, from rating curve extended above 7,900 ft³/s; minimum daily, 6 ft³/s, Oct. 1, 1939, minimum instantaneous discharge not determined.
EXTREMES OUTSIDE PERIOD OF RECORD.--Maximum discharge, about 10,000 ft³/s, Apr. 3, 2005, gage height, 11.9 ft, from floodmark in gage well.
WATER TEMPERATURE: October 2013 to current year.
pH: October 2013 to current year.
DISSOLVED OXYGEN: October 2013 to current year.
INSTRUMENTATION1.--A continuous water-quality monitor with water temperature, specific conductance, pH, and dissolved oxygen provides 15-minute-interval readings.
REMARKS1.--Interruption of record was due to malfunction of recording instrument.
EXTREMES FOR PERIOD OF DAILY RECORD1.--SPECIFIC CONDUCTANCE: Maximum, 234 uS/cm at 25 °C, Mar. 19, 2017; minimum, 97 uS/cm at 25 °C, Aug. 4, 2020. WATER TEMPERATURE: Maximum, 24.5 °C, Sept. 25, 27, 2017; minimum, 0.5 °C, Feb. 8, 17, Mar. 1, 4, 2014. pH: Maximum, 8.8, Jan. 26, 31, 2015; minimum, 6.1, July 2, 2016. DISSOLVED OXYGEN: Maximum, 15.8 mg/L, Feb. 14, 18, 19, 22, 23, Mar. 3, 5, 2016; minimum, 3.0 mg/L, June 25, 2020.
1 Water-Quality Records
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> Rating Information
This station managed by the NY Water Science Center Milford.

Available Parameters Available Period
2013-10-01  2021-09-25
1990-10-01  2021-09-25
2007-10-01  2021-09-25
2013-10-01  2021-09-25
2013-10-01  2021-09-25
2021-05-28  2021-09-25
2013-10-01  2021-09-25


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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: 980 09-25-2021   11:15 EST
Graph of  Discharge, cubic feet per second

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Daily discharge, cubic feet per second -- statistics for Sep 25 based on 63 water years of record more
Median Mean 75th
Most Recent
Value Sep 25
18.0 56 124 169 212 760 980

Gage height, feet

Most recent instantaneous value: 4.19 09-25-2021   11:15 EST
Graph of  Gage height, feet

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