science for a changing world Flooding in the Mississippi River Basin in Minnesota, Spring 2001 INTRODUCTION Department of Public Safety, Division of Resources, as well as other State and local Emergency Management, oral commun. agencies. Stage and discharge data During spring 2001 there was much July 9, 2001). gathered at these gages are used for flood flooding in the Mississippi River Basin in forecasting, operations of dams and Minnesota. Greater than normal Record flows were recorded at nine U.S. Geological Survey (USGS) diversions, managing emergency activities precipitation starting with late fall rains in continuous-streamflow gaging stations during floods, and performing follow-up 2000, greater than normal snowfalls, a within Minnesota or along the Wisconsin studies to better understand river flood- delayed snowmelt, and record rains in flow characteristics. This report April, all contributed to the flooding. Parts border. In addition, 14 stations recorded their 2nd or 3rd highest peaks of record. summarizes flooding in that part of the of the southern one-half of Minnesota had These gaging stations are maintained by Mississippi River Basin that includes streamflows of magnitudes not seen in stream-gaging stations within the borders more than 30 years. Approximately 50 the USGS as part of a network of gages used by the USGS, U.S. Army Corps of of Minnesota and monitoring points along counties were declared disaster areas with Engineers, National Weather Service, the Minnesota-Wisconsin border. greater than 34 million dollars in total Minnesota Department of Natural Peak stages and discharges are reported flood damage (S. Neudahl, included in this report for 44 stream- gaging stations (table 1) maintained by the USGS in the Mississippi River Basin. Stage, in feet, is based on an arbitrary scale established when a gaging station is installed. Discharges are instantaneous determinations of peak flow, in cubic feet per second. This peak flow information is ranked with the five greatest discharges of record for each station. In addition, flood- recurrence intervals are included for stations with at least 20 years of record, and/or with little influence on peak flows by regulation. Flood-recurrence intervals are expressed in years and are the probability of a flood of this magnitude occurring. A 25-year event can be expected to occur, on average, once every 25 years. This probability is independent of individual events, so two "25-year" floods can occur in successive years. It is also possible for the probability value assigned to a flood (for example, greater than 25-year event) to change over time. As peak flows are included from Mississippi River at St. Paul, Minnesota, April 23, 2001. Retrofitting a monitoring subsequent years, flood frequencies station for high water. (U.S. Geological Survey) previously determined can change U. S. Department of the Interior USGS Fact Sheet 002-02 U.S. Geological Survey January 2002 Table 1. Provisional flood information on major Minnesota streams in the Mississippi River Basin. [Peak stage and flow of 2001 compared with the five highest ranking flows of record. Provisional information is subject to review and change. Station names that are underlined indicate peak flows of record. Mi2, miles squared: ft3/s. cubic feet per second; ~, approximately; , not available; Minn, Minnesota; S. Dak, South Dakota; Wise, Wisconsin] Station Drainage Years of Recurrence U.S. Geological Survey gaging station and Peak Stage Peak Discharge number area peak flow Date of flood interval (downstream order number) (feet) (ft3/s) (Figure 1) (mi2) record (years) Mississippi River Basin 1 Mississippi River at Grand Rapids, Minn. 3.370 118 Sept. 3, 1948 '15.20 12,500 - (05211000) April 17, 1969 - 24,610 - May 29. 1950 - 4.160 - April 16, 1945 - 4,070 - Aug. 21, 1999 - 4,060 - Apr. 18,2001 10.06 32,740 - MI 2 Mississippi River at Aitkin, Minn. T^HiHHiB t 6,140 102 May 20, 1950 22.49 20,000 -- t (05227500) May 3, 1975 14.500 -- 1 I April 23, 1969 14,400 April 28, 2001 17.74 13,900 -- April 26, 1965 13,400 i 3 Mississippi River at Brainerd 7,320 14 April 30, 2001 16.70 17,8UU (05242300) April 10. 1997 16.03 15.400 April 30, 1996 14.59 14,000 - May 18, 1999 14.52 13,000 - July 10, 1993 13.65 12,200 - 4 Crow Wing River at Nimrod. Minn. 1,030 73 ' Oct. 10, 1973 7.35 3,700 50400 (05244000) April 18, 1979 7.24 3.610 50-100 April 13, 1965 *7.57 2,890 10-25 May 23, 1962 6.04 2,750 10-25 June 9, 1968 6.07 2,750 10-25 ,^_^^^^_^_. April 12, 2001 ,^1,720(24*1 2-5 |^ Mfe 5 Long Prairie River at Long Prairie, Minn. 434 30 July 22, 1972 9.37 3.270 50-100 (05245100) April 9, 2001 8.81 2,660 25-50 April 20, 1979 7.55 1,850 10-25 April 8, 1997 7.90 1,580 5-10 April 1, 1986 7.10 1,570 5-10 ' 6 Crow Wing River near Pillager. Minn.'*******1^^*^mt 3,520 33 April 12, 2001 12.12 17,200 (05247500) April 12. 1969 16,600 .- i April 7, 1997 11.73 16,300 - April 15, 1996 10.16 13,900 I April 14, 1974 12,200 7 Sauk River near St. Cloud, Minn. 1,030 67 April 13, 1965 10.68 9.100 200-500 (05270500) April 13. 1951 7.89 5,580 25-50 April 13, 1952 7.78 5,410 25-50 April 11, 1969 7.96 5,300 25-50 April 6, 1997 8.72 5,150 -25 April 14, 2001 8.37 4,780 (6th) 10-25 : '" " 50,100 Mississippi River at St. Cloud, Mintt^HH^HHH r 13,320 13 April 15, 2001 ' 11.74 (05270700) j^^^^^H April 8. 1997 11.44 46,900 May 17, 1999 9.38 33,800 April 22, 1996 8.70 27,300 May 2, 1994 8.24 23,300 L9 Elk River near Big Lake, Minn. 559 75 April 16, 1965 10.86 7,360 50-100 (05275000) April 10, 1969 10.08 5.980 25-50 April 10, 1952 10.36 5,330 10-25 May 7, 1912 10.10 5,180 10-25 June 16, 1984 9.87 4,980 10-25 April 27, 2001 9.46 4,520 (6th) 10-25 Table 1. Provisional flood information on major Minnesota streams in the Mississippi River Basin. (Continued) Station Drainage Years of Recurrence U.S. Geological Survey gaging station and Peak Stage Peak Discharge number area peak flow Date of flood interval (downstream order number) (feet) (ft3/s) (Figure 1) (mi2) record (years) * "10 ;e&w Kiver at Roekfedi MfiMi. ;(Q52»OQ!00) 16"24 136.14 April *>, 2001 11 Rum River near St. Francis, Mmn. 1,360 72 "April 2071965 11.57 (05286000) April 13, 1969 11.63 July 29, 1972 11.20 April 13, 1952 11.03 April 28, 2001 10.47 to Cask near Champlin MJmu 10:03" Kfaj; 15, Mississippi River at Anoka, Minn. 19,100 71 AprilT7~1965 (05288500) April 14, 1952 17.51 April 14, 1969 16.84 April 9, 1997 16.44 April 15, 2001 15.77 Minnesota River Basin :-«3B 54 * 12,15 m.-r 25, 1943 * 13.35 4,320 10-25 M,..r. 2^ 1 '^ ': H82 3^9-3 10-25 A,«ri2,2QOi f ,8.64, |J?1'' l..;25 Whetstone River near Big Stone City. S. Dak 398 75 Apnl 8, 2001 15.93 9,980 25-50 (05291000) April 6, 1997 14.21 7,940 10-25 April 8, 1969 14.32 6,870 10-25 April 8, 1952 13.64 5,710 10-25 April 11, 1947 13.95 5,500 10-25 64 12:85 4-850 fl B. J952 2,950 1*!7:?J' 1^? 10.76 52J|fl North Fork Yellow Bank River near Odessa, S. Dak 208 11 Apnl 8, 2001 16.84 7,300 (p5292704) Mar. 31, 1997 15.94 4,670 July 8, 1994 14.62 2,580 April 19, 1995 14.15 2,420 June 18, 1992 13.32 2,020 W Mfeftf sota "River nearTLae qui Parfp. J^fiim, i » * * ' * ' 4J050 55 &f*?il ^W» $ffi& ' " ' ' "^tihT^ 300% (U^OHOOD) Aptil I2U909 39.75 29*^0 AprBlG. B52 37.9*; 7 W7(XJ April 'S.,1'9* 36-8d t32,W ft. %ill,4v 1965 3fe.l7 ^j^Tta '18.03" " "" "l4,40o" 19 Chippewa River near Milan, Minn. 1,880 65 April 6, 1997 (05304500) April 10, 2001 14.63 11,600 April 9, 1969 8 15.45 11,400 July 6, 1995 8 13.48 8,440 April 6, 1952 8 12.12 6,930 Table 1. Provisional flood information on major Minnesota streams in the Mississippi River Basin. (Continued) Drainage Years of Recurrence . U.S. Geological Survey eaemg station and Peak Stage Peak Discharge number , , " , " , x area peak flow Date of flood interval . , N (downstream order number) (feet) (ft3/s) (Figure 1) (mi2) record (years) -92 April 12; 1P69: am 351100 50-LOfii AiadI 13,2001 2002 24,500 25-30, 21 Yellow Medicine River near Granite Falls, Minn. 664 71 April 10, 1969 14.90 17,200 100-200 (05313500) June 18, 1957 12.41 1 1,800 50-100 April 9, 1952 10.50 9,610 25-50 Mar. 31, 1997 11.80 9,020 25-50 June 21, 1993 11.46 8,380 10-25 April 26, 2001 8.00 3,860 (10th) 5-10 i "--gSjgQ- 'l|.W se-iee ?, is®? law. 5,370 25-50 April Ji4,.2001 3,930 s "Mar.