USGS Water-Year Summary 2018
04116000 GRAND RIVER AT IONIA, MI
LOCATION - Lat 42°58'19", long 85°04'09" referenced to North American Datum of 1927, in NW 1/4 sec.30, T.7 N., R.6 W., Ionia County, MI, Hydrologic Unit 04050006, on left bank 15 ft downstream from bridge on State Highway 66 in Ionia, 2.7 mi downstream from Prairie Creek, and at mile 87.
DRAINAGE AREA - 2,840 mi².
PERIOD OF RECORD - March to June 1931, July 1951 to current year. Gage-height records collected in this vicinity 1907-28 (flood seasons only) are contained in reports of the National Weather Service.
GAGE - Water-stage recorder. Datum of gage is 615.38 ft above NGVD 29. Mar. 19 to Sept. 24, 1931, nonrecording gage at site 1.5 mi upstream at different datum.
EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 25,100 ft³/s, Apr. 20, 2013, gage height, 24.69 ft; minimum discharge, 40 ft³/s, May 13, 1968.