USGS Water-Year Summary for Site 01363400

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	Available Parameters
	62614 Elevation, lake/res, NGVD29(Ins.) [East Basin (01363399)]
	62614 Elevation, lake/res, NGVD29(Ins.) [West Basin (01363398)]

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Water year 2023: 2022-10-01 to 2023-09-30

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USGS Water-Year Summary 2023

01363400 ASHOKAN RESERVOIR AT ASHOKAN, NY

LOCATION - Lat 41°57'01", long 74°12'30" referenced to North American Datum of 1927, Ulster County, NY, Hydrologic Unit 02020006, at gatehouse located at Dividing Weir Dyke, and 1.6 mi south of Shokan.

DRAINAGE AREA - 256 mi².

REVISIONS HISTORY - WDR NY-72-1: 1968. WDR NY-83-1: 1982 (M,m).

SURFACE-WATER RECORDS

PERIOD OF RECORD - September 1913 to September 2013 (month-end elevations, contents, and diversions). October 2013 to current year (daily observation elevations).

GAGE - Nonrecording gages read daily. Datum of gages is NGVD of 1929 (levels by Board of Water Supply, City of New York).

COOPERATION - Elevation records and capacity tables provided by New York City Department of Environmental Protection.

REMARKS - The reservoir is formed by the masonry Olive Bridge Dam across Esopus Creek and a series of earth embankments between hills. The reservoir is divided into two basins separated by a weir containing a gatehouse. Storage began Sept. 9, 1913. Usable capacity of West basin (01363398) 47,180 mil gal between minimum operating level elevation 495.50 ft and crest of spillway to East basin (01363399), elevation 590.00 ft; dead storage below minimum operating level 2,237 mil gal. Usable capacity of East basin 80,678 mil gal between elevation 500.00 ft and crest of spillway, elevation 587.10 ft; no dead storage. Figures given herein represent total contents for each basin. Reservoir impounds water for diversion (01363401) into Catskill Aqueduct (completed in 1917) for New York City water supply. Any flood spillage enters the Esopus Creek channel below Olive Bridge Dam.

West Basin capacity table (elevation, in feet, and total contents, in millions of gallons)

Elevation  Contents      Elevation  Contents
495.5      2,237         555.0      20,621
510.0      4,206         570.0      31,337
525.0      7,443         585.0      44,438
540.0     12,655         600.0      60,269

East Basin capacity table (elevation, in feet, and total contents, in millions of gallons)

Elevation  Contents      Elevation  Contents
500.0          0         560.0      41,063
515.0      2,666         575.0      61,376
530.0     11,157         590.0      85,543
545.0     24,364         600.0     103,175

EXTREMES FOR PERIOD OF RECORD - Maximum contents observed, in West basin, 54,541 mil gal, Apr. 3, 2005, elevation, 594.84 ft, in East basin, 89,411 mil gal, Mar. 31, 1951, elevation, 592.23 ft; minimum contents observed, in West basin, 9,098 mil gal, Oct. 24, 1926, elevation, 530.56 ft, in East basin, 8,394 mil gal, Oct. 24, 1926, elevation, 525.91 ft.