USGS Water-Year Summary for Site 05538020

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	Available Parameters
	00010 Temperature, water(Max.,Min.,Mean)
	00095 Specific cond at 25C(Max.,Min.,Mean)
	00300 Dissolved oxygen(Max.,Min.,Mean)
	00400 pH(Max.,Min.,Med.)
	32316 fChl, water, in situ(Max.,Mean,Min.)
	32319 fPC, water, in situ(Min.,Max.,Mean)
	63680 Turbidity, Form Neph(Mean,Min.,Max.)
	99141 CO2, water, diss, in situ(Max.,Mean,Min.)

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Water year 2025: 2025-10-01 to 2026-09-30

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USGS Water-Year Summary 2025

05538020 DES PLAINES RIVER IN LOCK CHANNEL AT ROCKDALE, IL

LOCATION - Lat 41°30'00", long 88°06'25" referenced to North American Datum of 1983, in NE 1/4 NW 1/4 SE 1/4 sec.20, T.35 N., R.10 E., Will County, IL, Hydrologic Unit 07120004,

REVISIONS HISTORY -

Revisions: Chlorophyll data for the period Feb. 19, 2016, to Jan. 12, 2022, was revised on Apr. 6, 2022, because data had been published using the incorrect parameter code. The values did not change only the parameter code was updated.

Revisions: Carbon Dioxide data for the period Aug. 2015 to Oct. 2024, was revised on May 23. 2025, because the data had been published using an incorrect parameter code and units.

SURFACE-WATER RECORDS

PERIOD OF RECORD -

SURFACE-WATER QUALITY:
WATER TEMPERATURE: August 2015 to October 2024.
SPECIFIC CONDUCTANCE: August 2015 to October 2024.
PH: August 2015 to October 2024.
DISSOLVED OXYGEN: August 2015 to October 2024.
TURBIDITY: August 2015 to October 2024.
DISSOLVED CARBON DIOXIDE: August 2015 to October 2024.
CHLOROPHYLL-A: February 2016 to October 2024.
PHYCOCYANIN: October 2021 to October 2024.
DISSOLVED CARBON DIOXIDE: August 2015 to October 2024.

GAGE - Water-stage recorder and water-quality monitor. Datum of gage is 0.43 ft below North American Vertical Datum of 1988. Gage height minus 0.43 ft equals NAVD88 elevation.

REMARKS - Accuracy of records is discussed in the annual Station Analysis archived at the USGS IL Water Science Center.

EXTREMES FOR PERIOD OF RECORD -
WATER TEMPERATURE: Maximum, 30.0 oC, Aug. 11, 2016; minimum 0.28 oC, Jan. 8, 2018.
SPECIFIC CONDUCTANCE: Maximum, 3396 us/cm, Feb. 8, 2021; minimum 395 us/cm, Sept. 27, 2019.
PH: Maximum, 8.63, Aug. 24, 2023; minimum 6.7, May 31, June 1, 2016, and July 15, 2017.
DISSOLVED OXYGEN: Maximum, 18.86 mg/L, July 23, 2023; minimum 3.3 mg/L, June 1 and 15, 2016.
TURBIDITY: Maximum, 134 FNU, Jan. 29, 2018; minimum 0.36 FNU, Aug. 27, 2024.
DISSOLVED CARBON DIOXIDE: Maximum, 1.55%, July 28, 2021; minimum 0.01%, Aug. 24, 2023.
CHLOROPHYLL-A: Maximum, 66.8 ug/L, July 28, 2024; minimum, 0.07 ug/L, March 06, 2016.
PHYCOCYANIN: Maximum: 2.55 ug/L, July 26, 2023; minimum: 0.0, multiple days in 2022 and 2023.