USGS Water-Year Summary 2021
01077400 COCKERMOUTH RIVER BELOW HARDY BROOK, AT GROTON, NH
LOCATION - Lat 43°42'14", long 71°50'00" referenced to North American Datum of 1983, Grafton County, NH, Hydrologic Unit 01070001, 50 ft upstream from North Groton Road, 200 ft downstream from Hardy Brook, 0.2 mi northeast of North Groton Road, Groton Road, and Sculptured Rocks Road intersection at Groton, and 9.1 mi northwest of South Main Street (NH 3A), Summer Street (NH 104), and Pleasant Street (NH 3A/104) intersection in Bristol.
DRAINAGE AREA - 21.4 mi².
PERIOD OF RECORD - Discharge records: September 2008 to current year.
GAGE - Water-stage recorder and crest-stage gage. Datum of gage is 608.42 ft above North American Vertical Datum of 1988.
COOPERATION - New Hampshire Department of Environmental Services and USGS Groundwater and Streamflow Information Program.
EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 8920 ft³/s, July 11, 2019, gage height, 11.99 ft; minimum discharge, 0.53 ft³/s, Sep 20 and 21, 2020.