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- Water-Year Summary reports summarize a year of hydrologic data in a printer-friendly format.
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USGS Water-Year Summary 2024
01478100 East Branch White Clay Creek tributary near London Grove, PA
LOCATION - Lat 39°51'30", long 75°47'01" referenced to North American Datum of 1927, Chester County, PA, Hydrologic Unit 02040205, on the left bank, 50 ft upstream from Spencer Road bridge, 2 miles north of Avondale Boro.
DRAINAGE AREA - 2.79 mi².
REVISIONS HISTORY - Prior to February 19, 2025, the datum of gage was erroneously reported as 330 ft above National Geodetic Vertical Datum of 1929.
SURFACE-WATER RECORDS
PERIOD OF RECORD - January 2020 to current year.
GAGE - Water-stage recorder, crest-stage gage, and water quality monitor. Datum of gage is 317.6 ft. above North American Vertical Datum of 1988 (GNSS survey). Prior to February 19, 2025, the datum of gage was erroneously reported as 330 ft above National Geodetic Vertical Datum of 1929. Satellite telemetry at station.
WATER-QUALITY RECORDS
PERIOD OF RECORD - Water Temperature and Specific Conductance, January 2020 to current year. Turbidity, July 2020 to current year.
COOPERATION - The station is maintained by the U.S. Geological Survey with funding provided by the U.S. Geological Survey Next Generation Water Observing System(NGWOS).
INSTRUMENTATION - Temperature, specific conductance, and turbidity are collected on a 15-minute interval from a water-quality sonde located 10 ft upstream from the gage and interfaced with site telemetry.
REMARKS - The reporting precision of the turbidity probe in low turbidity water is +/-0.3 FNU. The lowest reportable value, 0 FNU, is subject to this error and does not necessarily indicate a condition of zero turbidity. Turbidity values greater than 1300 FNU are beyond the specification of the sensor and are considered unreliable. Interruptions in the record were due to malfunctions of the equipment.
EXTREMES FOR PERIOD OF DAILY RECORD - SPECIFIC CONDUCTANCE: Maximum, 401 microsiemens/cm, Jan 18, 2020; minimum, 35 microsiemens/cm, Aug 7, 2020. WATER TEMPERATURE: Maximum, 23.3°C, Aug 9, 2022; minimum, 0.1°C, many days. TURBIDITY: Maximum 905 FNU, Aug 7, 2020; minimum, <0.3 FNU, many days.
