The statewide average precipitation of 38.79 inches for the 1993 water year was 122 percent of the normal annual precipitation of 31.77 inches for water years 1961-90. Average precipitation values ranged from 103 percent of normal in northwestern Wisconsin to 150 percent of normal in southwestern Wisconsin (Pamela Naber Knox, UW-Extension, Geological and Natural History Survey, written commun., 1993).
Runoff was variable for rivers throughout the State ranging from 99 percent in northcentral Wisconsin to 278 percent in southwestern Wisconsin. Departure of runoff in the 1993 water year from long-term average runoff is shown in figure 4, along with long-term average runoff for the period 1951-80. Runoff was lowest (99 percent of the average annual runoff from 1936-93) for the Wisconsin River at Rainbow Lake near Lake Tomahawk. Runoff was highest (278 percent of the average annual runoff from 1939-93) for the Pecatonica River at Darlington. The average annual runoff for the 1993 water year was the maximum for the period of record at 33 long-term stations (more than 10 years of record) in the southern half of Wisconsin.
A comparison of the annual discharge for the individual water years (1916-93) at the Oconto River near Gillett, Jump River at Sheldon, and Sugar River near Brodhead is shown figure 5, The comparisons of monthly and annual discharges for the 1993 water year to discharge for a 78-year base period at the same three gaging stations are shown in figure 6.
Spring runoff from snowmelt and major storms, in the period March through September 1993, caused floods with discharges that equalled or exceeded those with a recurrence interval of 10 years (Krug and others, 1991) at a number of crest-stage gage and gaging stations.
