USGS Water-Year Summary 2021
05501000 NORTH RIVER AT PALMYRA, MO
LOCATION - Lat 39°49'01.2", long 91°32'45.7" referenced to North American Datum of 1983, in SW 1/4 SW 1/4 SW 1/4 sec.14, T.58 N., R.6 W., Marion County, MO, Hydrologic Unit 07110004, on the left downstream abutment of County Road 329 bridge, 1.5 mi north of Palmyra, and 8.6 mi upstream from mouth.
DRAINAGE AREA - 354 mi².
PERIOD OF RECORD - Dec 1934 to current year. Low-flow records not equivalent prior to Oct 1, 2007, because of undetermined channel-flow loss between sites.
GAGE - Water-stage recorder and crest-stage gage. Datum of gage is 473.73 ft. above North American Vertical Datum of 1988. Prior to Oct 1, 1945, nonrecording gage at bridge 2 mi downstream; Oct 1, 1945, to Jun 22, 1951, nonrecording gage at site 1.8 mi downstream; Jun 23, 1951 to Oct 1, 2007 recording gage at site 1.8 mi downstream. Datum of these gages 464.81 ft above National Geodetic Vertical Datum of 1929 (levels by U.S. Army Corps of Engineers).
EXTREMES OUTSIDE PERIOD OF RECORD - Maximum stage prior to 1934, about 28.0 ft, from floodmarks, date unknown, at site 2 mi downstream, former datum.