This station is operated in cooperation
Green Island Power Authority
NYS Department of Environmental
Lat 42°45'08", long 73°41'20"
referenced to North American Datum of 1983, Albany County, NY,
Hydrologic Unit 02020003, on right bank at Green Island, just upstream
from Troy Lock and Dam, and 0.5 mi downstream from 5th branch Mohawk
, approximately (including
that above site of former auxiliary gage).
PERIOD OF RECORD.--
February 1946 to current year (October 1997
to September 2000, discharges only for days when inflatable rubber dam
was considered to have been collapsed; see REMARKS).
Water-stage recorder. Datum of gage is 0.31 ft below NGVD
of 1929 (Corps of Engineers benchmark). From July 1, 1946 to Mar. 12,
1962, auxiliary water-stage recorder on bypass channel at datum 10.59
ft higher. Power transducer on each turbine in powerplant. Since Oct.
1, 2008, auxiliary acoustic velocity meter about 1,600 ft upstream from
Records good except those for estimated daily
discharges, which are poor. Records include flow over spillway, flow
through lock, and flow through powerplant. Powerplant, located on the
right bank just downstream from gage, was inoperative from Nov. 20,
1960 to Feb. 23, 1971. An inflatable rubber dam was installed on the
spillway during August 1991. August 1991 through September 1997, and
since October 2000, estimated water-discharge data based on records for
Hudson River above Lock 1 near Waterford (station 01335754) and Mohawk
River at Cohoes (station 01357500) due to inflatable rubber dam.
October 1997 to September 2000, discharges only for days when
inflatable rubber dam was considered to have been collapsed. Satellite
gage-height and power transducer telemeter readings at station.
EXTREMES FOR PERIOD OF RECORD.--
Maximum discharge, 181,000
/s, Dec. 31, 1948, Aug. 29, 2011, gage height, 27.05 ft;
minimum discharge not determined; minimum gage height, 13.68 ft, July
6, 1981, when pool was lowered for inspection of flashboards.
EXTREMES OUTSIDE PERIOD OF RECORD.--
Flood of Mar. 19, 1936,
reached a stage of 29.48 ft at gage on opposite bank, from information
by Corps of Engineers (discharge, 215,000 ft3
/s). Flood of
Mar. 28, 1913, prior to construction of Sacandaga Reservoir and Troy
lock and dam, reached a stage about 0.2 ft higher upstream from former
dam near same site. Downstream from dams, flood in 1913 was about 3.3
ft higher than flood in 1936, from information by Corps of
Peak Flow and Stage Information