Interactive Flood Inundation Map Available

STATION.--01570500 SUSQUEHANNA RIVER AT HARRISBURG, PA
LOCATION.--Lat 40`15'17", long 76`53'11", Dauphin County, Hydrologic Unit 02050305, on east bank of City Island, 60 ft downstream from Market Street bridge in Harrisburg, 3,670 ft upstream from sanitary dam, and 1.7 mi upstream from Paxton Creek.
DRAINAGE AREA.--24,100 square miles.
PERIOD OF RECORD.--October 1890 to current year.
GAGE.--Water-stage recorder and heated tipping bucket precipitation gage. Concrete control since Aug. 29, 1916. Datum of gage is 290.01 ft above National Geodetic Vertical Datum of 1929. Prior to Oct. 1, 1928, non-recording gage at Walnut Street Bridge 600 ft upstream, and Oct. 1, 1928, to Aug. 31, 1975, water-stage recorder at site 3,170 ft downstream, all gages at same datum.
COOPERATION.--Station established and maintained by the U.S. Geological Survey. Funding for the operation of this station is provided by Exelon Generation, the Pennsylvania Department of Environmental Protection and the U. S. Geological Survey.
REMARKS.--Water temperature data collection at the City Island site was discontinued on March 25, 2015. Regulations and diversions from 15 flood-control reservoirs upstream, combined capacity of 1,571,000 acre-ft.
WATER QUALITY DATA FROM THE WALNUT STREET PIER LOCATION IS SEASONAL AND IS NOT TRANSMITTED VIA SATELLITE TELEMETRY AND THEREFORE WILL ONLY BE UPDATED ABOUT EVERY 6 WEEKS.

The 30-minute precipitation data for this station are temporary and will only be displayed for 120 days. Time series of 1-hour or cumulative daily values will NOT be available for retrieval following the 120-day display period. Although the instrumentation is calibrated at least once a year, the temporary classification means that documented routine inspections and other quality assurance measures are not performed that would make the data acceptable for archival, retrieval, or future use in general scientific or interpretive studies.

Water-quality parameters at this station can vary substantially at different locations in the river. Therefore, water-quality data displayed here characterizes conditions only at the location where water-quality equipment is deployed.
GAGE HEIGHTS OF IMPORTANCE.-
Supplied by USGS: Maximum recordable gage height (stage sensor operational limit) - 45.2 ft; Data transmitter operational limit - 46.2 ft;
Supplied by NWS: Action stage 11 ft, recreational use of City Island begins to be curtailed; river interests should monitor conditions; Flood stage-17 ft, basements of residences and businesses on both banks flood; the parking lot of City Island begins to take on water; Moderate flood stage-20 ft, a number of homes in West Fairview, Dauphin and Harrisburg flood; Major flood stage-23 ft, evacuations are necessary in the Shipoke area of Harrisburg; the water level reaches the corner of Keller and Front Streets.