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USGS Water-Year Summary 2024
16238500 Waihi Stream at Honolulu, Oahu, HI
LOCATION - Lat 21°19'42.1", long 157°48'03.1" referenced to North American Datum of 1983, Honolulu County, HI, Hydrologic Unit 20060000, on left bank, 100 feet upstream from Waaloa Way bridge, 700 feet upstream from confluence with Waiakeakua Stream, and 4.2 miles northeast of Honolulu Post Office in Honolulu.
DRAINAGE AREA - 1.12 mi². from automated delineation using 10-meter National Elevation Dataset digital elevation model data dated September 2006 and Watershed Boundary Dataset dated May 2008, using UTM Zone 4 projection, NAD 83 horizontal datum.
REVISIONS HISTORY - WDR HI-10-1: Drainage Area. Turbidity data on November 7, 2019 (0305-0430) was revised on April 20, 2020. Peak gage height and discharge for January 25, 2021 were revised on October 5, 2021. Qualifier was removed from turbidity unit values from May 1 (2140) to May 2 (0205), 2022 and May 2 (1200-2205), 2022 on June 27, 2023.
SURFACE-WATER RECORDS
PERIOD OF RECORD - Operated as a continuous gaging station from May 1913 to January 1921, and August 1925 to September 1983. Partial-record station April 1997 to October 2011. Resumed continuous monitoring October 2011 to current year. Prior to 1960, published as West Branch Manoa Stream near Honolulu.
GAGE - Water-stage recorder and eroded combination Parshall flume and concrete weir. Datum of gage is 290.77 feet above mean sea level. Prior to June 17, 1914, non-recording gage at same site at different datum. June 17, 1914 to January 16, 1921, water-stage recorder at site 150 feet upstream at different datum. August 4, 1925 to September 30, 1983, water-stage recorder at present site at different datum. Non-recording gage at present site and datum, November 1998 to September 2011.
REMARKS - Datum of gage is 290.77 feet, mean sea level, reference to City and County of Honolulu levels to City and County elevation monument dated May 19, 1997.
EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 3,250 ft³/s, January 16, 1921, gage height, 10.4 feet, from floodmarks, site and datum then in use. Minimum recorded, 0.06 ft³/s, February 11 and 12, 2012.
WATER-QUALITY RECORDS
PERIOD OF RECORD - March 1970 to September 1983, November 2011 to current year.
PERIOD OF DAILY RECORD - SUSPENDED-SEDIMENT CONCENTRATION AND SUSPENDED-SEDIMENT DISCHARGE: October 2014 to current year.
TURBIDITY, water, unfiltered, monochrome near infa-red LED light, 780-900 nm, detection angle 90 +/- 2.5 degrees: October 2015 to current year.
INSTRUMENTATION - Automatic pumping sediment sampler October 2011 to current year. Turbidity sensor October 2015 to current year.
EXTREMES FOR PERIOD OF RECORD - SUSPENDED-SEDIMENT CONCENTRATION: Maximum daily mean 280 mg/L (estimate), September 15, 2015; minimum, 0.2 mg/L on many days.
SUSPENDED-SEDIMENT DISCHARGE: Maximum daily, 280 tons (estimated), September 15, 2015; minimum, 0 tons on many days.
TURBIDITY, water, unfiltered, monochrome near infa-red LED light, 780-900 nm, detection angle 90 +/- 2.5 degrees: Maximum, 5,080 formazin nephelometric units (FNU), April 02, 2013; minimum, 0.0 FNU on many days.
