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. . 30 HYDROLOGIC AND HUMAN ASPECTS OF THE 1976-77 DROUGHT During January and February 1977 several parts of the regions received above normal precipitation whereas other parts had less than 50 percent of normal. Generally, March precipitation was above normal, but in April amounts less than 50 percent of normal fell in North Dakota and near the Illinois-Iowa bor- der. Rains in May 1977 near the Sour is and Red Rivers brought the monthly values up to more than twice normal, but most of Iowa had less than 75 percent of normal. June rainfall was still low in Iowa, and it was down to half normal along part of the Red River valley. Most of the two regions had above normal rainfall from July through November 1977 though southern Wisconsin had less than normal rainfall in September and October. Soil moisture available to corn at Lamber- ton, Minn., about 115 mi southwest of St. Paul dropped below average in July 1974 and re- mained below average through 1976 except for a brief period in June and July 1975 and was below or near the wilting point in August and September each year. In Wisconsin, the soil-moisture deficit was as much as 15 in. for the last half of 1976. The deficit was reduced in late February 1977 when about 1 in. of precipitation occurred. Though the ground was frozen, it had a honey- comb texture; therefore most of the precipi- tation entered the soil rather than producing runoff. The lack of soil moisture is vividly shown (fig. 12) by the parched soil in Iowa dur- ing 1976. Records of streamflow were obtained 1911- 17 and since 1928 on the Vermilion River near Tower in northeastern Minnesota. During the drought in the 1930's, minimum daily dis- charges ranged from 31 to 34 ft 3/s, but there was virtually no flow during the spring of 1977. The index station on the lower Wisconsin River at Muscoda, 53 mi west of Madison, Wis., has been operated for 64 years. Prior to 1976, minimum monthly flows occurred in seven different years between 1924 and 1964. Three of the minimums occurred in 1934 and three in 1964. During the 1976-77 drought period five new minimum monthly flows oc- curred-in September through December 1976 and in May 1977. These 5 months were included in the 16 month period from June 1976 through September 1977 when monthly flows were below the median flows each month. The deficit amounts to 3.8 million Figure 12. Parched soil in Iowa in 1976. Photo by R. J. Modersohn, Des Moines Sunday Register. acre-ft or 49 percent of the average flow for the 16 months. Local areas in Iowa were affected by drought in 1974, and conditions got worse in 1975 and 1976 until the driest 9 months of record occurred between May 1976 and Febru- ary 1977. Streamflow decreased to the extent that it approached or became less than the 7- day, 10-year low flow which is the minimum flow required by the water-quality standards before waste-water discharges can be made. lllinois was affected by the drought but to a lesser degree than the neighboring States. Precipitation and streamflow were below nor- mal, but timely rains during the 1977 growing season alleviated drought conditions. The low flows that occurred between October 1976 and July 1977 are not considered rare events. Another effect of the drought besides re- duced volumes of runoff is the reduction in peak discharges. Peak discharges on the Mis-