U.S. Department of the Interior

U.S. Geological Survey

Open-File Report 2006–1067

Prepared in cooperation with the Iowa Department of Transportation and 

the Iowa Highway Research Board (Project HR-140)

Flood of May 23, 2004, in the Turkey and 

Maquoketa River Basins, Northeast Iowa 

Flood of May 23, 2004, in the Turkey and 

Maquoketa River Basins, Northeast Iowa

By David A. Eash

Prepared in cooperation with the Iowa Department of Transportation 

and the Iowa Highway Research Board (Project HR-140)

Open-File Report 2006−1067

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

DIRK KEMPTHORNE, Secretary

U.S. Geological Survey

P. Patrick Leahy, Acting Director

U.S. Geological Survey, Reston, Virginia: 2006

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Suggested citation:

Eash, D.A., 2006, Flood of May 23, 2004, in the Turkey and Maquoketa River Basins, northeast Iowa: U.S. Geological Survey Open-File Report 2006-1067, 35 p.

Front cover: Map of Iowa showing location of Turkey and Maquoketa River Basins (shaded area) and river 

reaches profiled in the report (shown with thicker lines).
iii

Contents

Abstract.................................................................................................................................................. 1

Introduction............................................................................................................................................ 1

Basin Descriptions................................................................................................................................ 4

Flood History.......................................................................................................................................... 6

Flood of May 23, 2004 ........................................................................................................................... 7

Storm Description........................................................................................................................ 7

Flood Description....................................................................................................................... 13

Flood Profile......................................................................................................................................... 17

Summary............................................................................................................................................... 18

Acknowledgments..................................................................................................................... 19

Literature Cited.................................................................................................................................... 19

Appendix. Temporary Bench Marks and Reference Points ........................................................ 32

Turkey River ................................................................................................................................ 32

Volga River.................................................................................................................................. 33

Maquoketa River........................................................................................................................ 33

Figures

1–2. Maps showing:

 1. Turkey River Basin and lines of equal rainfall for 72 hours ending at 1. Turkey River Basin and lines of equal rainfall for 72 hours ending at 

7:00 a.m., May 23, 2004................................................................................................. 2

 2. Maquoketa River Basin and lines of equal rainfall for 72 hours ending at 

7:00 a.m., May 23, 2004................................................................................................. 3

3. Graph showing hourly rainfall for May 21–23, 2004, at rain gages in the 

Turkey and Maquoketa River Basins and vicinity ........................................................ 11

4. Discharge hydrographs at four continuous-record, streamflow-gaging 

stations in the Turkey River Basin, May 21–27, 2004 ................................................... 14

5. Discharge hydrographs at three continuous-record, streamflow-gaging 

stations in the Maquoketa River Basin, May 21–27, 2004........................................... 15

6–9: Graphs showing profile of the May 2004 flood for the Turkey River, Iowa:

 6 River miles 1.7 to 39.1................................................................................................. 21

 7. River miles 1.7 to 15.................................................................................................... 22

 8. River miles 15 to 30..................................................................................................... 23

 9. River miles 30 to 39.1.................................................................................................. 24

10. Graph showing profile of the May 2004 flood for the Volga River, Iowa; 

river miles 0.4 to 9.3. .......................................................................................................... 25

11–15: Graphs showing profile of the May 2004 flood for the Maquoketa River, Iowa:

 11. River miles 92.2 to 143.7............................................................................................. 26

 12. River miles 92.2 to 105................................................................................................ 27

 13. River miles 105 to 120................................................................................................. 28

 14. River miles 120 to 135................................................................................................. 29

 15. River miles 135 to 143.7.............................................................................................. 30
iv

Conversion Factors, Vertical Datum, and Abbreviated 

Units of Measurement

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

square mile (mi2) 2.590 square kilometer (km2) 

Flow rate

cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s)

Elevation or vertical coordinate information is referenced to the National Geodetic Vertical 

Datum of 1929 (NGVD 29). Elevation refers to distance above or below NGVD 29. NGVD 29 

can be converted to the North American Vertical Datum of 1988 (NAVD 88) by using the 

National Geodetic Survey conversion utility available at http://www.ngs.noaa.gov/TOOLS/

Vertcon/vertcon.html.

Water year is the 12-month period from October 1 through September 30. The water year 

is designated by the calendar year in which it ends and which includes 9 of the 12 months. 

Thus, the year ending September 30, 2004, is called the “2004 water year.”

Tables

1. National Flood Insurance Program Bureau and Statistical Agent Iowa 

loss report for selected counties, May 21−31, 2004, as of July 31, 2005..................... 5

2. Approved Iowa Public Assistance Program project costs for selected 

counties for disaster number 1518, May−June 2004, as of September 16, 2005....... 6

3. Maximum stages and discharges for 2004 and selected largest-flood years, 

and the corresponding recurrence intervals, at streamflow-gaging stations 

in the Turkey and Maquoketa River Basins, Iowa.......................................................... 8

4. Twenty-four-hour rainfall amounts at selected rain gages in northeast 

and east-central Iowa during May 21−23, 2004............................................................ 12

5. Magnitude and frequency of theoretical rainfall amounts for selected 

storm periods in the Northeast Iowa Climatological Division.................................... 12

6. Elevation of high-water marks used in the May 2004 flood profile for 

the Turkey River, Iowa....................................................................................................... 17

7. Elevation of high-water marks used in the May 2004 flood profile for 

the Volga River, Iowa......................................................................................................... 17

8. Elevation of high-water marks used in the May 2004 flood profile for 

the Maquoketa River, Iowa .............................................................................................. 18
Abstract

Severe flooding occurred on May 23, 2004, in the 

Turkey River Basin in Clayton County and in the Maquoketa River Basin in Delaware County following intense 

thunderstorms over northeast Iowa. Rain gages at Postville 

and Waucoma, Iowa, recorded 72-hour rainfall of 6.32 and 

6.55 inches, respectively, on May 23. Unofficial rainfall 

totals of 8 to 10 inches were reported in the Turkey River 

Basin. The peak discharge on May 23 at the Turkey River 

at Garber streamflow-gaging station was 66,700 cubic feet 

per second (recurrence interval greater than 500 years) and 

is the largest flood on record in the Turkey River Basin. 

The timing of flood crests on the Turkey and Volga Rivers, 

and local tributaries, coincided to produce a record flood 

on the lower part of the Turkey River. Three large floods 

have occurred at the Turkey River at Garber gaging station 

in a 13-year period. Peak discharges of the floods of June 

1991 and May 1999 were 49,900 cubic feet per second 

(recurrence interval about 150 years) and 53,900 cubic feet 

per second (recurrence interval about 220 years), respectively. The peak discharge on May 23 at the Maquoketa 

River at Manchester gaging station was 26,000 cubic feet 

per second (recurrence interval about 100 years) and is the 

largest known flood in the upper part of the Maquoketa 

River Basin.

Introduction

Thunderstorms caused severe flooding along the 

lower Turkey (fig. 1) and upper Maquoketa (fig. 2) Rivers in northeast Iowa in May 2004. New maximum peak 

discharge records were set during May 22–23, 2004, at 

10 U.S. Geological Survey (USGS) streamflow-gaging 

stations (gaging stations) that included the mainstems of 

the Turkey River in Clayton County, the Maquoketa River 

in Delaware County, and Bloody Run Creek in Clayton 

Flood of May 23, 2004, in the Turkey and Maquoketa 

River Basins, Northeast Iowa

By David A. Eash

County, and included tributary streams in the Turkey River 

Basin in Clayton County, the Winnebago River Basin 

in Cerro Gordo County, the Cedar River Basin in Black 

Hawk County, the Boone River Basin in Hancock County, 

the Mosquito Creek Basin in Pottawattamie County, 

and the Nishnabotna River Basin in Shelby County (the 

Nishnabotna River and Mosquito Creek are not shown in 

figs. 1–2). Significantly high peak stages and discharges 

were measured during May 22–30, 2004, at gaging stations 

along the Wapsipinicon River at Independence, Anamosa, 

and near De Witt; on the Winnebago River at Mason City; 

on the Shell Rock River at Shell Rock; and along the 

Cedar River at Cedar Falls, Waterloo, Cedar Rapids, and 

near Conesville.

The severe storms of May 21–23, 2004, caused flash 

flooding across north-central and northeast Iowa. Flash 

flooding of local streams in Cedar Rapids, Fredericksburg 

in Chickasaw County, Independence, Mason City, and 

Des Moines flooded homes and businesses, and forced the 

evacuation of residents. Due to flooding and road closures 

in Chickasaw County, the Chickasaw County Sheriff’s 

Office and Emergency Management asked motorists to 

avoid travel through the county (Palmer and Heinselman, 

Waterloo Cedar-Falls Courier, May 23, 2004). On May 

26, state officials reported that more than 1,400 homes had 

been damaged or destroyed since May 21 and that most of 

the damage had been caused by flooding; and the National 

Weather Service announced that at least 37 tornadoes had 

been reported in the State since May 21 (Dorman and 

Haugen, Waterloo Cedar-Falls Courier, May 26, 2004). 

A woman was killed and the driver was injured when 

their vehicle struck a washed-out section of a road near 

Hazleton, in Buchanan County, during the early morning 

hours of May 23 (Gravelle, Cedar Rapids Gazette, May 24, 

2004).

A State disaster declaration was issued on May 23, 

2004, for 16 counties. On May 25, a Federal disaster 

declaration was issued to help Iowans recover from losses 
Figure 1. Turkey River Basin and lines of equal rainfall for 72 hours ending at 7:00 a.m., May 23, 2004.

   Flood of May 23, 2004, in the Turkey and Maquoketa River Basins, Northeast Iowa
Figure 2. Maquoketa River Basin and lines of equal rainfall for 72 hours ending at 7:00 a.m., May 23, 2004.

Introduction   
caused by the severe storms, tornadoes, and flooding. The 

Federal disaster declaration (number 1518), which began 

with 14 counties, and increased to 75 counties, provided 

aid for losses incurred in Iowa between May 19 and June 

24, 2004. The initial 14 counties declared disaster areas 

were: Bremer, Buchanan, Butler, Cass, Cerro Gordo, 

Clayton, Delaware, Fayette, Hancock, Humboldt, Jones, 

Linn, Mitchell, and Pocahontas. On July 27, 2004, Federal Emergency Management Agency (FEMA) officials 

reported 4,813 individuals had registered for aid, more 

than $11 million of aid had been approved for individuals, 

families, and businesses in Iowa, and an additional nearly 

$2 million had been obligated for improvements to infrastructure (Federal Emergency Management Agency, 2004).

Private property damage claims reported for residential and non-residential buildings in 10 selected counties 

in northeast Iowa are shown in table 1 (Bonnie Shepard, 

FEMA, National Flood Insurance Program Bureau and 

Statistical Agent, written commun., September 2005). 

Approved public assistance project costs (assistance to 

local governments for the repair of disaster-damaged public facilities) for the same 10 selected counties in northeast 

Iowa are shown in table 2 (Dennis Harper, Iowa Homeland 

Security and Emergency Management Division, State 

Hazard Mitigation Officer, written commun., September 

2005).

This report provides information about the May 

2004 thunderstorms and ensuing flood in the Turkey and 

Maquoketa River Basins. Flood elevations at selected sites 

along the Turkey, Volga, and Maquoketa Rivers in Clayton 

and Delaware Counties are presented as flood profiles.

Flood-peak and water-surface-elevation profile information is needed for the economical and safe location and 

design of bridges and other structures on or over streams 

and the adjacent flood plains. Defining the limits of flood 

inundation and establishing encroachment limits on flood 

plains are related problems needing this information. 

Data for major floods are needed to compute flood-peak 

discharges and calibrate water-surface-elevation profile 

models for sites along streams. This report was prepared 

in cooperation with the Iowa Department of Transportation and the Iowa Highway Research Board. A list of other 

Iowa flood-profile reports published by the USGS can be 

obtained from the World Wide Web at http://ia.water.usgs.

gov/projects/profiles/.

Basin Descriptions

The Turkey and Maquoketa River Basins are adjoining watersheds draining from the northwest to the southeast across northeast Iowa. The two drainage basins, the 

river reaches profiled, the location USGS gaging stations 

within these river basins, and the location of bridge sites 

used in the May 23, 2004, flood profiles are shown in 

figures 1–2.

The Turkey River Basin originates in Howard County 

and flows about 148 mi through the cities of Spillville, 

Clermont, Elgin, and Elkader to its mouth at the Mississippi River in southeastern Clayton County (fig. 1). The 

Turkey River Basin includes parts of eight counties and 

drains 1,684 mi2 (Larimer, 1957). The Little Turkey and 

Volga Rivers are principal tributaries to the Turkey River. 

The Little Turkey River, with a drainage area of 355 mi2

(Larimer, 1957), originates in Howard County and flows 

about 53 mi through the city of Waucoma to its mouth in 

Fayette County. The Volga River, with a drainage area of 

403 mi2 (Larimer, 1957), originates in Fayette County and 

flows about 81 mi through the cities of Fayette and Volga 

to its mouth in Clayton County.

Most of the Turkey River Basin lies within two landform regions of the State. The northwest or upper part of 

the basin drains the low-relief plain of the Iowan Surface 

landform region (Prior, 1991; Horick and Soenksen, 1989; 

Iowa Natural Resources Council, 1958) (landform regions 

are not shown in fig. 1). Although streams draining the 

Iowan Surface are well established, stream gradients are 

low. In Fayette County, the Turkey River crosses from the 

Iowan Surface landform region to the Paleozoic Plateau 

landform region, which drains the southeast or lower part 

of the basin. The bedrock-dominated, erosional topography 

of the Paleozoic Plateau is characterized by plateau-like 

uplands, integrated drainage networks with steep gradients, 

and deeply entrenched valleys (Prior, 1991; Horick and 

Soenksen, 1989; Iowa Natural Resources Council, 1958). 

In parts of the basin, the Turkey River and its tributaries have cut deeply into the bedrock formations. Such 

entrenched river valleys usually display strong bedrock 

control in their courses (Prior, 1991). Land use in the basin 

is predominately agricultural with some livestock and timber operations. Five low-head dams have been constructed 

across the Turkey River; two low-head dams have been 

constructed across the Little Turkey River and one has 

been constructed across the Volga River (Iowa Conservation Commission, 1979). The City of Elkader dam is the 

largest dam on the Turkey River at a height of 21 ft.

   Flood of May 23, 2004, in the Turkey and Maquoketa River Basins, Northeast Iowa
Table 1. National Flood Insurance Program Bureau and Statistical Agent Iowa loss report for selected counties, May 21–31, 

2004, as of July 31, 2005.

[Source: Bonnie Shepard, Federal Emergency Management Agency, National Flood Insurance Program Bureau and Statistical Agent, written commun., 

September 2005. ND, no data]

County Occupancy Buildings with damage Building damage

(dollars)

Contents damage

(dollars)

Buchanan Single-family residential 34 289,345 41,090

Buchanan Multiple occupancy ND ND ND

Buchanan Non-residential 4 36,566 0

Chickasaw Single-family residential 1 1,551 0

Chickasaw Multiple occupancy ND ND ND

Chickasaw Non-residential ND ND ND

Clayton Single-family residential 15 322,765 13,185

Clayton Multiple occupancy1 1 7,950 0

Clayton Non-residential 3 24,594 0

Delaware Single-family residential 1 7,484 0

Delaware Multiple occupancy ND ND ND

Delaware Non-residential 3 343,357 328,421

Dubuque Single-family residential ND ND ND

Dubuque Multiple occupancy ND ND ND

Dubuque Non-residential ND ND ND

Fayette Single-family residential ND ND ND

Fayette Multiple occupancy ND ND ND

Fayette Non-residential ND ND ND

Howard Single-family residential ND ND ND

Howard Multiple occupancy ND ND ND

Howard Non-residential ND ND ND

Jackson Single-family residential ND ND ND

Jackson Multiple occupancy ND ND ND

Jackson Non-residential ND ND ND

Jones Single-family residential 2 25,622 0

Jones Multiple occupancy ND ND ND

Jones Non-residential ND ND ND

Winneshiek Single-family residential ND ND ND

Winneshiek Multiple occupancy ND ND ND

Winneshiek Non-residential ND ND ND

Total 64 1,059,234 382,696

1

Two to four family residential.

Basin Descriptions 
The Maquoketa River Basin originates in Fayette 

County and flows about 150 mi through the cities of 

Manchester, Monticello, and Maquoketa to its mouth at the 

Mississippi River in eastern Jackson County (fig. 2). The 

Maquoketa River Basin includes parts of nine counties and 

drains 1,879 mi2 (Larimer, 1957). The North Fork Maquoketa River, a major tributary to the Maquoketa River with 

a drainage area of 592 mi2 (Larimer, 1957), originates in 

Dubuque County and flows about 97 mi through the cities 

of New Vienna, Dyersville, and Cascade to its mouth in 

Jackson County.

Similar to the Turkey River Basin, most of the 

Maquoketa River Basin lies within two landform regions 

of the State. The northwest or upper part of the basin 

drains the Iowan Surface landform region. In Delaware 

County, the Maquoketa River crosses from the gently 

rolling terrain of the Iowan Surface to the steep-to-gently 

rolling terrain of the Southern Iowa Drift Plain landform 

region, which drains the southeastern or lower part of the 

basin (Prior, 1991). In northwest Delaware County, the 

Maquoketa River valley changes for a few miles from a 

gently sloped valley to a rugged gorge in Backbone State 

Park. Farther downstream in central Delaware County, 

a few miles southeast of Manchester, the Maquoketa 

River enters a canyon-like valley that persists throughout 

much of the remaining length of the river (Iowa Natural Resources Council, 1958). Land use in the basin is 

predominately agricultural and includes some wooded 

areas. Eight low-head dams have been constructed across 

the Maquoketa River (Iowa Conservation Commission, 

1979); no dams have been constructed across the North 

Fork Maquoketa River. Six of the dams on the Maquoketa 

River were originally built for hydroelectric power (Iowa 

Natural Resources Council, 1958); only the Lakehurst dam 

upstream from the city of Maquoketa in Jackson County 

(fig. 2) is currently operating as a hydroelectric dam. The 

Lake Delhi dam is the largest dam on the Maquoketa 

River at a height of 38 ft (Iowa Conservation Commission, 1979). Lake Delhi (Federally recognized as Hartwick 

Lake) is approximately 8 mi in length and 450 acres in 

area. The local name “Lake Delhi” was adopted by area 

residents in recognition of the nearby town of Delhi in 

Delaware County (fig. 2).

Flood History

Continuous records of streamflow have been collected in the Turkey River Basin since October 1932, 

and intermittent records since August 1913, at the USGS 

Table 2. Approved Iowa Public Assistance Program project costs for selected counties for disaster number 1518, May−June 

2004, as of September 16, 2005.

[Source: Dennis Harper, Iowa Homeland Security and Emergency Management Division, State Hazard Mitigation Officer, written commun., September 

2005. ND, no data]

County Number of 

applicants

Debris 

removal 

(dollars)

Emergency 

protective 

measures 

(dollars)

Roads and 

bridges 

(dollars)

Water 

control 

facilities

(dollars)

Buildings 

and 

equipment1

(dollars)

Utilities 

(dollars)

Parks and 

other 

(dollars)

Total2

(dollars)

Buchanan 8 74,016 35,517 1,021,495 ND ND ND 145,698 1,276,726

Chickasaw 3 2,075 14,011 342,965 ND 500 10,059 10,110 379,720

Clayton 19 114,496 150,208 760,344 4,800 21,866 63,928 124,957 1,240,599

Delaware 6 12,084 30,325 295,185 ND ND 6,473 53,678 397,745

Dubuque 5 31,413 54,133 242,805 ND ND ND 22,361 350,713

Fayette 7 27,028 20,994 560,036 ND ND 36,741 11,242 656,041

Howard 4 3,000 4,394 204,844 40,690 ND ND 24,059 276,987

Jackson 0 ND ND ND ND ND ND ND ND

Jones 7 3,900 48,959 94,485 ND ND 56,782 13,993 218,119

Winneshiek 4 1,570 3,146 116,987 ND ND ND 4,668 126,371

Total 63 269,582 361,687 3,639,146 45,490 22,366 173,983 410,766 4,923,021

1

Includes some insurance deductibles, and is not the estimated total cost for repair.

2

Does not include demolition projects because costs have not been estimated as of September 16, 2005.

 Flood of May 23, 2004, in the Turkey and Maquoketa River Basins, Northeast Iowa
gaging station Turkey River at Garber (station number 

05412500). Continuous records of streamflow have been 

collected in the Maquoketa River Basin since September 

1913, at the USGS gaging station Maquoketa River near 

Maquoketa (station number 05418500). Peak stages, 

discharges, and recurrence intervals for the largest known 

floods, including the May 2004 flood, are listed in table 

3 for gaging stations in the Turkey and Maquoketa River 

Basins. The gaging stations listed in table 3 also are listed 

in the USGS National Water Information System (NWIS) 

database, and users may obtain surface-water data for Iowa 

gaging stations, including information on types of data 

available and years of data collection, at http://waterdata.

usgs.gov/ia/nwis/sw. Descriptions of historic floods in the 

Turkey and Maquoketa River Basins are limited; available 

information is summarized for floods that occurred in the 

Turkey River Basin in 1922, 1947, 1972, 1979, 1991, and 

1999 in the reports Turkey/Volga River flood of March 19, 

1979 (Iowa Natural Resources Council, 1980), Floods 

of July 12, 1972, March 19, 1979, and June 15, 1991, in 

the Turkey River Basin, Northeast Iowa (Eash and Koppensteiner, 1996), and Floods of May 17−20, 1999, in the 

Volga and Wapsipinicon River Basins, Northeast Iowa

(Ballew and Fischer, 2000); and for floods that occurred in 

the Maquoketa River Basin in 1925, 1944, 1947, and 2002 

in the report Flood of June 4−5, 2002, in the Maquoketa 

River Basin, East-Central Iowa (Eash, 2005).

Flood of May 23, 2004

Table 3 indicates that the flood of May 23, 2004, 

in the Turkey River Basin is the largest flood on record 

for the period 1902, 1914−16, 1919−27, 1930, and 

1933−2004, and is probably the largest flood since at 

least 1890. Table 3 also indicates that the flood of May 

23, 2004, in the upper Maquoketa River Basin is probably 

the largest flood for the period 1925, 1928–30, 1933−73, 

1976−83, and 2001−2004. A comparison of peak discharges for floods measured at two gaging stations located 

on the Maquoketa River near Manchester (station numbers 05416900 and 05417000; table 3) indicates that the 

2004, 1925, and 1947 floods were the first, second, and 

third largest floods, respectively, along a 3-mi reach of the 

Maquoketa River downstream of Manchester. However, 

photographs taken during the 1925, 1947, and 2004 floods 

at the same location on West Main Street in Manchester 

appear to indicate that the 1925, 1947, and 2004 floods 

were the first, second, and third highest floods, respectively, in the downtown area of Manchester (photographs 

provided by Larry Schmidt, Street Superintendent, City 

of Manchester, written commun., October 2005). Schmidt 

also reported that significant floods occurred in Manchester in 1960, 1969, 1993, and 1999.

Storm Description

The flood was the result of a series of thunderstorms 

that crossed north-central and northeast Iowa on May 

21−23. The following rainfall information was provided 

by Harry Hillaker, State Climatologist, Iowa Department 

of Agriculture and Land Stewardship (written commun., 

September 2005):

The bulk of the precipitation occurred from 

late evening of the 21st to about sunrise on the 

22nd and again from late evening of the 22nd to 

the early a.m. of the 23rd. The highest official 

rainfall total in the State of 7.22 in. was recorded 

at Mason City in north-central Iowa, while the 

highest amount in northeast Iowa of 6.38 in. was 

recorded at the Elkader 1 SE rain gage in Clayton County. However, the rain gage at the Mississippi River Lock and Dam 9 near Lynxville, 

Wisconsin (located on the border of Allamakee 

County, Iowa), reported 8.34 in. This amount 

was confirmed by a second rain gage located at 

the same site. Frequent, and sometimes heavy, 

rainfall saturated soils in the two-week period 

preceding the heavy rains of May 21–23. At the 

Lansing weather station in Allamakee County, 

May 2004 was the wettest month (14.87 in.) in 

98 years of record (old record was 13.57 in. in 

July 1999).

The following rainfall information was summarized 

from the U.S. Department of Commerce, National Oceanic 

and Atmospheric Administration, and National Climatic 

Data Center (2004a) and the U.S. Department of Commerce, National Oceanic and Atmospheric Administration, 

and National Weather Service (2004a; 2004b).

Strong to severe storms developed north of a 

stationary front across Iowa and northern Illinois 

during the afternoon and evening hours of May 

21. A strong low level jet continuously pumped 

copious amounts of moisture over the front 

that resulted in heavy rains of 3 to 6 in., causing widespread flash flooding across northeast 

Iowa. There were reports from north-central 

to northeast Iowa of 2 to 4 in. of rainfall in a 

little more than an hour’s time. Some of the 

storms produced large hail, damaging winds, 

and tornadoes. A low level jet developed two 

squall lines in western Iowa during the evening 

Flood of May 23, 2004 
Table 3. Maximum stages and discharges for 2004 and selected largest-flood years, and the corresponding recurrence 

intervals, at streamflow-gaging stations in the Turkey and Maquoketa River Basins, Iowa.

[mi2, square miles; ft3/s, cubic feet per second; <, less than; --, not determined; >, greater than]

Site

Period of peakflow record

(water years)

Drainage 

area

(mi2)

Date Peak stage1

(feet)

Peak 

discharge

(ft3/s)

Recurrence

interval2

(years)

Turkey River Basin

Crest-stage gaging station

05411530 North Branch Turkey River 

near Cresco

1966–93 19.5 6/29/1969

8/25/1990

8/15/1993

92.72

93.88

94.61

2,400

3,500

4,500

13

20

35

Continuous-record gaging station

05411600 Turkey River at Spillville

1947, 1956–73, 

1978–91

177 6/--/1947

7/12/1972

8/25/1990

3

18.4

16.73

16.76

4

10,000

8,600

8,320

25

15

14

Crest-stage gaging station

05411650 Crane Creek tributary near 

Saratoga

1953–75 4.06 8/31/1962 6.56 1,830 15

Crest-stage gaging station

05411700 Crane Creek near Lourdes

1953–90 75.8 8/31/1962

6/29/1969

6/04/1974

15.70

14.10

13.71

11,900

8,840

7,700

50

20

14

Continuous-record gaging station

05411850 Turkey River near Eldorado

2001–2004 641 6/15/1991

5/23/2004

3

18.78

19.61

4

17,600

19,700

5

11

5

16

Continuous-record gaging station

05412000 Turkey River at Elkader

1916, 1929, 

1933–42

891 6/01/1916

3/16/1929

4/01/1933

3

34.30

--

--

4

30,000

6,725,200

6,723,800

45

19

15

Continuous-record gaging station

05412020 Turkey River above French 

Hollow Creek at Elkader

1991, 2002–

2004

903 6/15/1991

5/23/2004

3

27.32

25.57

38,300

33,300

5

150

5

70

Crest-stage gaging station

05412030 French Hollow Creek near 

Elkader

1990–2004 3.56 5/17/1999

5/23/2004

4

19.9

3

20.23

4

3,100

4

3,300

19

20

Continuous-record gaging station 

05412056 Unnamed Creek near Luana

1987–1992 1.15 6/15/1991 16.82 8880 510

Continuous-record gaging station

05412060 Silver Creek near Luana

1988–98 4.39 6/15/1991 14.97 83,300 120

Continuous-record gaging station

05412100 Roberts Creek above Saint Olaf

1987–2001 70.7 6/15/1991 27.88 819,600 200

Continuous-record gaging station

05412400 Volga River at Littleport

2000–2004 348 3/19/1979

6/15/1991

5/17/1999

5/23/2004

3

18.04

3

18.51

3

25.36

21.98

4

12,600

4

13,500

9

30,000

21,000

5

9

5

10

5

320

5

50

Continuous-record gaging station

05412500 Turkey River at Garber

1902, 1914–16, 

1919–27, 1930, 

1933–2004

1,545 2/23/1922

3/19/1979

6/15/1991

5/17/1999

5/23/2004

3,1028.06

25.59

3

30.10

30.91

3

32.80

32,300

26,000

8

49,900

53,900

66,700

20

9

150

220

>500

 Flood of May 23, 2004, in the Turkey and Maquoketa River Basins, Northeast Iowa
Site

Period of peakflow record

(water years)

Drainage 

area

(mi2)

Date Peak stage1

(feet)

Peak 

discharge

(ft3/s)

Recurrence

interval2

(years)

Maquoketa River Basin

Crest-stage gaging station

05416200 Lamont Creek tributary near 

Lamont

1991–2004 1.78 6/01/2000

5/23/2004

20.13

11--

4

635

>700

9

>11

Continuous-record gaging station

05416900 Maquoketa River at 

Manchester

2001–2004 275 6/04/2002

5/23/2004

18.35

21.66

10,800

26,000

9

100

Crest-stage gaging station

05416972 Sand Creek near Manchester

1991–2004 11.0 6/04/2002

5/23/2004

19.31

11.80

4

4,290

860

35

2

Continuous-record gaging station

05417000 Maquoketa River near 

Manchester

1925, 1928–30, 

1933–73, 

1976–83

305 6/15/1925

6/13/1947

7/09/1951

--

21.40

19.65

1225,400

20,000

16,800

130

60

30

Crest-stage gaging station

05417530 Plum Creek near Earlville

1966–91 41.1 9/13/1972

6/21/1974

9/26/1981

88.34

88.75

88.22

4

4,800

4

6,200

4

4,500

20

45

18

Crest-stage gaging station

05417590 Kitty Creek near Langworthy

1966–92 14.4 7/19/1969

7/08/1986

90.24

88.68

8

3,700

2,100

100

17

Continuous-record gaging station

05417700 Bear Creek near Monmouth

1944, 1958–76 61.3 6/--/1944

9/21/1965

1321.50

13.76

-- 

7,340

--

80

Continuous-record gaging station

05418400 North Fork Maquoketa River 

near Fulton

1999–2004 505 5/18/1999

6/05/2002

5/23/2004

16.46

19.87

15.34

10,700

22,600

9,680

6

110

5

Continuous-record gaging station

05418450 North Fork Maquoketa River 

at Fulton

1974, 1977–91, 

2002

516 6/05/2002 21.21 422,600 100

Continuous-record gaging station

05418500 Maquoketa River near 

Maquoketa

1903, 1914–

2004

1,553 --/--/1903

6/27/1944

6/05/2002

5/25/2004

1423.50

1424.70

34.09

25.61

43,200

48,000

47,900

15,900

40

60

60

2

Crest-stage gaging station

05418645 Williams Creek near Charlotte

1989–2004 1.77 5/29/1996

5/23/2004

13.02

--

4

990

--

14

--

1All values at current datums.

2 Interpolated using Bulletin 17B flood-frequency analyses (Interagency Advisory Committee on Water Data, 1982) computed through the 2004 water 

year and rounded to nearest 5 years for 20- to 50-year recurrence intervals, to nearest 10 years for 50- to 200-year recurrence intervals, and to nearest 20 

years for 200- to 500-year recurrence intervals.

3Gage height determined from floodmark.

4Estimated.

5Computed using regional regression equations (Eash, 2001).

6Discharge is maximum daily average.

7From records by Central States Power and Light Corporation (Iowa Geological Survey, 1944).

8Discharge computed from indirect measurement.

9Based on indirect measurement of discharge at Mederville.

10Maximum gage height known since 1890.

11Flood peak higher than top of crest-stage gage at 20.6 feet, peak stage not determined.

12Discharge computed by Prof. F.A. Nagler, University of Iowa (U.S. Geological Survey, 1964).

13 Stage affected by backwater. 

14Prior to Sept. 30, 1972, gaging station at different site and datum.

Table 3. Maximum stages and discharges for 2004 and selected largest-flood years, and the corresponding recurrence 

intervals, at streamflow-gaging stations in the Turkey and Maquoketa River Basins, Iowa—Continued.

[mi2, square miles; ft3/s, cubic feet per second; <, less than; --, not determined; >, greater than]

Flood of May 23, 2004 
of May 21. The first squall line traveled north of 

the stationary front and raced east across Iowa 

causing storms that brought renewed heavy rain 

in the early a.m. hours of May 22 over areas in 

northeast Iowa that had been saturated by storms 

just hours earlier. The second squall line moved 

across eastern Iowa during the morning hours 

of May 22. The second squall line had weakened considerably during the night so severe 

weather was sporadic, but it produced heavy rain 

over areas that were already saturated and thus 

renewed flash flooding.

A second consecutive night of flash flooding 

affected much of northeast Iowa, when rainfall 

amounts of 2 to 4 in. occurred in three hours during the early a.m. of May 23. Again, two squall 

lines developed in the late afternoon of May 22 

in western Iowa, one north and one south of the 

stationary front. These squall lines raced east 

across eastern Iowa and renewed flash flooding 

across parts of northeast Iowa that had received 

three rounds of heavy rains in the past 48 hours. 

Unofficial rainfall totals of 8 to 10 in. were 

reported in the Turkey River Basin.

Figure 3 shows hourly rainfall amounts for May 

21–23, 2004, at four selected rain gages in northeast Iowa. 

Hourly data collected at Cascade, McGregor, Spillville, 

and Strawberry Point (figs. 1–2) may provide a general 

indication of the timing and intensity of the rainfall in the 

Turkey River Basin and the upper part of the Maquoketa 

River Basin. The greatest intensity of rainfall recorded at 

the four rain gages occurred at Strawberry Point (fig. 3D) 

between midnight and 1 a.m. on May 23 during which 

1.6 in. of rain fell. Data from the four rain gages (fig. 3) 

indicate that all of the rainfall occurred during a 56-hour 

period, of which most of the rainfall occurred during about 

a 46-hour period from 4 a.m. on May 21 to 2 a.m. on May 

23. Data from the four rain gages (fig. 3) also indicate that 

Spillville recorded the greatest 24-hour rainfall of 4.9 in. 

and McGregor recorded the greatest 48-hour rainfall of 6.0 

in. (24- and 48-hour periods are independent of observation times).

Figures 1 and 2 each show an isohyetal map of the 

areal distribution of rainfall for the 72-hour period ending at 7:00 a.m. on May 23, 2004; data were provided 

by Harry Hillaker, State Climatologist, Iowa Department 

of Agriculture and Land Stewardship (written commun., 

September 2005). A 72-hour time period is shown in 

figures 1 and 2 to indicate total rainfall for the storms 

because most of the rainfall occurred during three 24-hour 

collection periods (7:00 a.m. observation times). Table 4 

lists each 24-hour rainfall amount for May 21–23, 2004, 

for the 17 rain gages nearest to the Turkey and Maquoketa 

River Basins (U.S. Department of Commerce, National 

Oceanic and Atmospheric Administration, and National 

Climatic Data Center, 2004b, 2004c; and Iowa Department 

of Agriculture and Land Stewardship, State Climatologist 

Office, 2004). Rainfall recorded during May 19–20 ranged 

from no rain to 0.05 in. at 15 of the 17 rain gages listed in 

table 4 (12 of the stations reported no rain; rainfall data 

for May 19–20 are not listed in table 4); rainfalls of 0.2 in. 

at Spillville and 1.05 in. at Cresco were reported for this 

48-hour time period. A 72-hour rainfall total is listed in 

table 4 for May 21–23 to include all relevant rainfall that 

could be considered contributing to the flood of May 23, 

2004, with the exception of the additional rainfall recorded 

at Cresco on May 20th. Seventy-two hour rainfall recorded 

at Postville and Waucoma on May 23 were 6.32 and 6.55 

in., respectively.

The Rainfall Frequency Atlas of the Midwest (Huff 

and Angel, 1992) provides a table of the mean distribution 

of theoretical rainfall amounts for climatological divisions 

in Iowa for selected rain periods and recurrence intervals. 

Table 5 lists the magnitude and frequency of theoretical 

rainfall amounts for selected rain periods (durations) from 

the table in Huff and Angel (1992) for the Northeast Iowa 

Climatological Division. Fourteen of the 17 rain gages 

listed in table 4 are in the Northeast Iowa Climatological 

Division; the Coggon, Central City, and Maquoketa rain 

gages are located in the East-Central Climatological Division (U.S. Department of Commerce, National Oceanic 

and Atmospheric Administration, and National Climatic 

Data Center, 2004b, 2004c; and Iowa Department of Agriculture and Land Stewardship, State Climatologist Office, 

2004).

Tables 5 and 3 list recurrence intervals for two different components of a hydrologic event—rainfall and runoff, 

respectively, and for different locations in the Turkey 

and Maquoketa River Basins. Recurrence interval is the 

average interval of time during which a given rainfall or 

flood will be equaled or exceeded once. For example, a 

flood with a magnitude that is expected to be exceeded 

on average once during any 100-year period (recurrence 

interval) has a 1-percent chance of being exceeded during 

any particular year. This flood, commonly termed the 

100-year flood or 1-percent-annual-chance flood, is one of 

several selected theoretical peak discharges against which 

actual flood peaks are compared. Although the recurrence 

interval represents the long-term average period between 

rainfalls or floods of a specific magnitude, rare rainfalls or 

floods could occur at shorter intervals or even within the 

same year.

10 Flood of May 23, 2004, in the Turkey and Maquoketa River Basins, Northeast Iowa
21 21.25 21.5 21.75 22 22.25 22.5 22.75 23 23.25 23.5 23.75 24

0

0.5

1

1.5

2

21 21.25 21.5 21.75 22 22.25 22.5 22.75 23 23.25 23.5 23.75 24

0

0.5

1

1.5

2

May 21, 2004 May 22, 2004 May 23, 2004

TIME, IN HOURS

RAINFALL, IN INCHES

21 21.25 21.5 21.75 22 22.25 22.5 22.75 23 23.25 23.5 23.75 24

0

0.5

1

1.5

2

21 21.25 21.5 21.75 22 22.25 22.5 22.75 23 23.25 23.5 23.75 24

0

0.5

1

1.5

2

A. Cascade

B. McGregor

C. Spillville

D. Strawberry Point

12 p.m. 12 a.m. 12 p.m. 12 a.m. 12 p.m. 12 a.m. 12 p.m.

Hourly rainfall shown for hour ending.

Greatest 24-hour rainfall shown is 2.7 inches

Greatest 48-hour rainfall shown is 3.5 inches.

Total 72-hour rainfall shown is 3.5 inches.

Hourly rainfall shown for hour ending.

Greatest 24-hour rainfall shown is 3.5 inches.

Greatest 48-hour rainfall shown is 6.0 inches.

Total 72-hour rainfall shown is 6.1 inches.

Hourly rainfall shown for hour ending.

Greatest 24-hour rainfall shown is 4.9 inches.

Greatest 48-hour rainfall shown is 5.8 inches.

Total 72-hour rainfall shown is 6.0 inches.

Hourly rainfall shown for hour ending.

Greatest 24-hour rainfall shown is 4.1 inches.

Greatest 48-hour rainfall shown is 5.3 inches.

Total 72-hour rainfall shown is 5.3 inches.

Figure 3. Hourly rainfall for May 21–23, 2004, at four rain gages in the Turkey and Maquoketa River Basins and vicinity (U.S. 

Department of Commerce, National Oceanic and Atmospheric Administration, and National Climatic Data Center, 2004c). Location 

of rain gages shown in figures 1–2.

Flood of May 23, 2004 11
Table 4. Twenty-four-hour rainfall amounts at selected rain gages in northeast and east-central Iowa during May 21–23, 2004.

[ND, no data; T, trace. Location of rain gages shown in figures 1–2.]

Rain gage Observation

time

24-hour rainfall, in inches1,2,3 Greatest 48-hour 

rainfall total

(inches)

72-hour rainfall 

total

(inches) May 21, 2004 May 22, 2004 May 23, 2004

Cascade Midnight3 0.6 2.2 0.7 43.5 3.5

Central City Midnight3 0.6 0.7 0.3 31.6 1.6

Coggon 6 a.m. 0.00 1.72 2.24 3.96 3.96

Cresco 1 NE 8 a.m. 1.15 2.88 0.78 4.03 4.81

Elkader 5 SSW 8 a.m. 0.65 2.26 2.50 4.76 5.41

Fayette 7 a.m. 0.89 2.78 2.31 5.09 5.98

Guttenberg L & D 10 6 a.m. 0.00 2.87 1.96 4.83 4.83

Independence 6 a.m. 0.00 1.91 3.66 5.57 5.57

Manchester #2 7 a.m. 0.02 1.93 1.02 2.95 2.97

Maquoketa 4 W 7 a.m. T 1.21 0.56 1.77 1.77

McGregor Midnight3 2.4 1.4 2.3 46.0 6.1

New Hampton 7 a.m. 0.76 3.96 1.10 5.06 5.82

Oelwein 2 S 7 a.m. 0.18 2.27 2.22 4.49 4.67

Postville 7 a.m. 1.06 4.33 0.93 5.39 6.32

Spillville Midnight3 3.6 1.7 0.7 45.8 6.0

Strawberry Point Midnight3 0.9 2.6 1.8 45.3 5.3

Waucoma 7 a.m. 0.80 4.85 0.90 5.75 6.55

1Climatological Data, Iowa (U.S. Department of Commerce, National Oceanic and Atmospheric Administration, and National Climatic Data Center, 

2004b).

2 Iowa Climate Review (Iowa Department of Agriculture and Land Stewardship, State Climatologist Office, 2004).

3Hourly Precipitation Data, Iowa (U.S. Department of Commerce, National Oceanic and Atmospheric Administration, and National Climatic Data 

Center, 2004c).

4Calculated from hourly precipitation data shown on figure 3.

Table 5. Magnitude and frequency of theoretical rainfall amounts for selected storm periods in the Northeast Iowa 

Climatological Division.

[Rainfall amounts from Huff and Angel (1992)]

Duration

(hours)

Rainfall (inches) for indicated recurrence interval (years)

10 25 50 100

24 4.31 5.11 5.73 6.36

48 4.69 5.62 6.34 7.09

72 5.14 6.19 7.00 7.84

12 Flood of May 23, 2004, in the Turkey and Maquoketa River Basins, Northeast Iowa
Flood Description

As a result of the intense rainfall, severe flooding occurred in the lower part of the Turkey River Basin 

and the upper part of the Maquoketa River Basin. Peak 

discharges on the Turkey River for the flood of May 23, 

2004, of 33,300 ft3/s at the Turkey River above French 

Hollow Creek at Elkader gaging station (station number 

05412020, State Highway 13, fig. 1) and 66,700 ft3/s at 

the Turkey River at Garber gaging station (station number 

05412500, County Road C43), were determined for the 

flood (table 3). The peak discharge of the 2004 flood at the 

Garber gaging station is the largest flood on record in the 

Turkey River Basin. The recurrence interval for the peak 

discharge of 66,700 ft3/s at the Turkey River at Garber 

gaging station is estimated to be greater than 500 years as 

computed through the 2004 water year using Bulletin 17B 

flood-frequency analyses (Interagency Advisory Committee on Water Data, 1982). Three large floods have occurred 

at the Turkey River at Garber gaging station in a 13-year 

period. Peak discharges of the floods of June 15, 1991, and 

May 17, 1999, were 49,900 ft3/s (recurrence interval about 

150 years) and 53,900 ft3/s (recurrence interval about 220 

years), respectively.

The peak discharge on the Maquoketa River of 

26,000 ft3/s at the Maquoketa River at Manchester gaging 

station (station number 05416900, U.S. Highway 20) is the 

largest flood on record for the upper part of the Maquoketa 

River Basin. The recurrence interval for the peak discharge 

of 26,000 ft3/s at the Maquoketa River at Manchester gaging station is estimated to be approximately 100 years as 

computed through the 2004 water year using Bulletin 17B 

flood-frequency analyses.

Discharge hydrographs for continuous-record, gaging 

stations for May 21–27, 2004, are shown in figure 4 for 

all four active gaging stations in the Turkey River Basin 

and are shown in figure 5 for all three active gaging stations in the Maquoketa River Basin. Flooding (recurrence 

interval of 10 years or greater) that began in the upper 

part of the Turkey River Basin on May 22 at the Turkey 

River at Eldorado gaging station (fig. 4A) became major 

flooding (recurrence interval of 50 years or greater) in the 

lower part of the basin at the Turkey River above French 

Hollow Creek at Elkader, the Volga River at Littleport, 

and the Turkey River at Garber gaging stations on May 

23 (figs. 4B, 4C, and 4D). The largest measured discharge 

in the Turkey River Basin occurred at the Turkey River 

at Garber gaging station (fig. 4D), which measures the 

combined flows of the Turkey and Volga Rivers (fig. 1). 

The discharge hydrographs shown in figure 4 indicate that 

the floods on the Turkey and Volga Rivers combined to 

produce a record flood at the Turkey River at Garber gaging station. The peak discharge at the Turkey River above 

French Hollow Creek at Elkader gaging station, located 

approximately 17.9 mi upstream of the Garber gaging station, occurred at 7:00 a.m. on May 23. The peak discharge 

at the Volga River at Littleport gaging station, located 

approximately 10.5 mi upstream of the Garber gaging station, occurred at 8:30 a.m. on May 23. The travel distance 

and timing of these two flood crests coincided with other 

local tributary flow (primarily Roberts and Elk Creeks) to 

produce the largest peak discharge on record at the Turkey 

River at Garber gaging station at 12:00 a.m. on May 23. 

Although the 1991 flood (38,300 ft3/s) exceeded the 2004 

flood (33,300 ft3/s) at the Turkey River above French Hollow Creek at Elkader gaging station and the 1999 flood 

(30,000 ft3/s) exceeded the 2004 flood (21,000 ft3/s) at the 

Volga River at Littleport gaging station, the magnitude and 

timing of the crests of the 2004 flood on the Turkey and 

Volga Rivers combined to cause the 2004 flood at the Turkey River at Garber gaging station (66,700 ft3

/s) to exceed 

either of these previous floods at Garber (49,900 ft3/s in 

1991 and 53,900 ft3/s in 1999).

Major flooding in the upper part of the Maquoketa 

River Basin began on May 23 and peaked that same day 

at the Maquoketa River at Manchester gaging station (fig. 

5A). The discharge hydrographs in figure 5 indicate the 

smallest increase in discharge occurred in the lower part of 

the basin at the North Fork Maquoketa River at Fulton and 

Maquoketa River near Maquoketa gaging stations (figs. 

5B and 5C), which is consistent with rainfall amounts 

depicted in figure 2. The largest measured discharge in the 

Maquoketa River Basin occurred at the Maquoketa River 

at Manchester gaging station (fig. 5A), which measures 

discharge for the upper part of the basin. The flood attenuated downstream of the Manchester gaging station because 

of flood-plain and lake-storage effects (Lake Delhi and 

Lakehurst Dam).

The magnitude of the 2004 flood in comparison to 

selected theoretical, flood-frequency discharges is shown 

in figures 4 and 5. Recurrence intervals estimated for the 

2004 flood at Eldorado (fig. 4A), Elkader (fig. 4B), and 

Littleport (fig. 4C) gaging stations are about 16, 70, and 50 

years, respectively (table 3), as computed using regional 

regression equations (Eash, 2001). The recurrence interval 

for the 2004 flood at the Turkey River at Garber (fig. 4D) 

gaging station is estimated to be greater than 500 years 

(table 3), as computed through the 2004 water year using 

Bulletin 17B flood-frequency analyses (Interagency Advisory Committee on Water Data, 1982). At least 10 years 

Flood of May 23, 2004 13
21 22 23 24 25 26 27 28

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

21 22 23 24 25 26 27 28

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

21 22 23 24 25 26 27 28

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

May 2004

21 22 23 24 25 26 27 28

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

A. 05411850 Turkey River at Eldorado

B. 05412020 Turkey River above French Hollow Creek at Elkader

C. 05412400 Volga River at Littleport

21 22 23 24 25 26 27

100-year flood

50-year flood

25-year flood

10-year flood

100-year flood

50-year flood

25-year flood

10-year flood

100-year flood

50-year flood

Flood stage

Flood stage

25-year flood

10-year flood

D. 05412500 Turkey River at Garber

10-year flood

25-year flood

50-year flood

100-year flood

200-year flood

500-year flood

DISCHARGE, IN CUBIC FEET PER SECOND

Figure 4. Discharge hydrographs at four continuous-record, streamflow-gaging stations in the Turkey River Basin, May 21–27, 

2004. Location of gaging stations shown in figure 1.

14 Flood of May 23, 2004, in the Turkey and Maquoketa River Basins, Northeast Iowa
21 22 23 24 25 26 27 28

0

5,000

10,000

15,000

20,000

25,000

30,000

21 22 23 24 25 26 27 28

0

5,000

10,000

15,000

20,000

25,000

30,000

May 2004

DISCHARGE, IN CUBIC FEET PER SECOND

21 22 23 24 25 26 27 28

0

5,000

10,000

15,000

20,000

25,000

30,000

A. 05416900 Maquoketa River at Manchester

B. 05418400 North Fork Maquoketa River near Fulton

C. 05418500 Maquoketa River near Maquoketa

21 22 23 24 25 26 27

100-year flood

50-year flood

25-year flood

10-year flood

100-year flood

50-year flood

25-year flood

10-year flood

2-year flood

5-year flood

Flood stage

Flood stage

5-year flood

2-year flood

Figure 5. Discharge hydrographs at three continuous-record, streamflow-gaging stations in the Maquoketa River Basin, May 

21–27, 2004. Location of gaging stations shown in figure 2.

Flood of May 23, 2004 15
of gaged annual peak discharges are required to compute 

flood-frequency analyses using the “Bulletin 17B” method. 

Regional regression equations were used to compute 

flood-frequency discharges for the Eldorado, Elkader, and 

Littleport gaging stations because peak discharge records 

for these three gages were less than 10 years. Recurrence 

intervals estimated for the 2004 flood at the Manchester 

(fig. 5A), Fulton (fig. 5B), and Maquoketa (fig. 5C) gaging 

stations are about 100, 5, and 2 years, respectively (table 

3), as computed through the 2004 water year using the 

“Bulletin 17B” method.

The flood stage established by the National Weather 

Service for the Turkey River above French Hollow Creek 

at Elkader gaging station is 12.0 ft, which is the stage at 

which minor flooding occurs in areas near the river (at 

http://www.crh.noaa.gov/ahps2/hydrograph.php?wfo=arx

&gage=ekdi4&view=1,1,1,1,1,1). The Turkey River above 

French Hollow Creek at Elkader gaging station was above 

flood stage from May 22–25 (fig. 4B), and the peak stage 

of 25.57 ft (table 3) exceeded the flood stage at this site by 

almost 13.6 ft. The flood stage for the Turkey River at Garber gaging station is 17.0 ft, which is the stage at which 

minor flooding begins in the communities of Garber, 

Osterdock, and Millville (at http://www.crh.noaa.gov/

ahps2/hydrograph.php?wfo=arx&gage=grbi4&view=1,

1,1,1,1,1). The Turkey River at Garber gaging station was 

above flood stage from May 22–26 (fig. 4D), and the peak 

stage of 32.80 ft (table 3) exceeded the flood stage at this 

site by 15.8 ft. The flood stage for the Maquoketa River 

at Manchester gaging station is 14.0 ft, which is the stage 

at which water is on West Main Street and affects residences on the south side of town (at http://www.crh.noaa.

gov/ahps2/hydrograph.php?wfo=dvn&gage=mchi4&view

=1,1,1,1,1,1). The Maquoketa River at Manchester gaging 

station was above flood stage from May 23–24 (fig. 5A), 

and the peak stage of 21.66 ft (table 3) exceeded the flood 

stage at this site by almost 7.7 ft. The flood stage for the 

Maquoketa River near Maquoketa gaging station is 24.0 ft, 

which is the stage at which water begins affecting agricultural fields in the Maquoketa area and several storm sewers 

in town (at http://www.crh.noaa.gov/ahps2/hydrograph.

php?wfo=dvn&gage=maqi4&type=0&view=1,1,1,1,1,1). 

The Maquoketa River near Maquoketa gaging station was 

above flood stage from May 23–24 and again from May 

25–26 (fig. 5C), and the peak stage of 25.61 ft on May 25 

(table 3) exceeded the flood stage by about 1.6 ft. Flood 

stages are not available for the other three gaging stations 

shown in figures 4 and 5.

The following flood description information presented in this section was obtained from newspaper 

articles in the Cedar Rapids Gazette (Gravelle, May 24, 

2004; Hogan, May 25, 2004; Love, May 26, 2004) and 

the Des Moines Register (Jordan, May 24, 2004; Leys, 

May 24, 2004; Jordan, July 13, 2004; Jordan, February 

10, 2005; Harris, September 18, 2005), and from on-line 

sources obtained from the U.S. Department of Commerce, 

National Oceanic and Atmospheric Administration, and 

National Climatic Data Center (2004a). Flash flooding 

was reported in many locations following the storms of 

May 21–23. In the Turkey and Maquoketa River Basins, 

flooding damaged several bridges and caused numerous 

roads to become impassable, closed, or washed-out. The 

flooding closed State Highway 13 in downtown Manchester and north of Strawberry Point, and closed U.S. Highway 52 at Millville and State Highway 187 at the Fayette 

County line. On May 23, the Clayton County Sheriff’s 

Office banned travel to and from Volga, Garber, Elkport, 

and Littleport. In Elkader, flooding along the Turkey 

River in the early morning hours of May 23, threatened to 

overtop the dike, and forced emergency crews to evacuate 

more than 25 homes on the south side of town, shut off 

gas and electricity, and use a boat to rescue campers from 

the City Park and nearby Deer Run Resort, reported Paul 

Olson, Elkader Fire Chief. In Volga, about 24 people were 

evacuated from rising floodwaters on the Volga River. In 

Manchester, flooding along the Maquoketa River forced 

evacuations of some businesses and homes. In Arlington, 

in southeastern Fayette County, law enforcement officials 

reported water 3 ft deep inundating roads in town during 

the early morning hours on May 23.

Flooding on Turkey River devastated the town of 

Elkport. Residents of Elkport, population 88, and Garber, 

population 103, went on alert on May 22 because of the 

rapid rise of the Turkey and Volga Rivers, which converge 

just upstream of the two communities. In Elkport, the 

dike protecting the town from the Turkey River and Elk 

Creek broke at 11:30 a.m. on May 23, for the first time 

in 50 years, and the entire community was flooded. By 

the afternoon, most of Elkport’s 30 houses were under at 

least 8 ft of water, causing the town to be a total loss. The 

combination of floodwaters in Elk Creek and the Turkey 

River broke the dike and sandbagging became ineffective, reported Roger Bolsinger, Fire Chief of Elkport and 

Garber. In nearby Garber, 10–12 homes were flooded by 

the Turkey River. The May 2004 flood resulted in private 

home buyout assistance totaling more than $2 million from 

Federal, State, and local governments to remove 42 homes 

in Iowa from flood plains. Most of the buyout assistance 

approved by FEMA, about $1.2 million, was for 28 homes 

in Elkport, and about $425,000 was approved for eight 

16  Flood of May 23, 2004, in the Turkey and Maquoketa River Basins, Northeast Iowa
homes in Garber, with the remaining assistance approved 

for two homes in Independence, two homes in Mason 

City, one home in Manchester, and one home in Clayton 

County.

Flood Profile

To develop a flood profile, the USGS measured the 

elevation of high-water marks (HWMs) at selected bridge 

and dam sites along selected reaches of the Turkey and 

Maquoketa Rivers. River miles were determined for the 

bridge and dam sites using a geographic information 

system (GIS) to measure the distance along each river 

reach from its mouth using USGS 1:24,000-scale topographic-map data. HWMs were measured at all Federal 

and State Highway bridges and at USGS gaging stations 

along the selected river reaches. Additional HWMs were 

measured at county road bridges to keep the maximum 

distance between points at about 10 river miles. The flood 

profiles were determined using HWMs generally located 

immediately downstream and one bridge-length upstream 

from selected bridges. The HWMs were flagged within 

4 days of the flood peak, surveyed to temporary bench 

marks (see appendix) at bridges and dams within 2 weeks 

of the flood peak, and were later referenced to the National 

Geodetic Vertical Datum of 1929 by differential leveling or 

differential positioning using a global positioning system 

(GPS). The line connecting the marks on the profiles (figs. 

6–15 following references) is a linear interpolation and, 

therefore, only approximates the flood elevation between 

marks; the line does not depict the effects on the profile 

caused by intermediate bridges or flood-plain and channel features. Additional HWMs were provided by David 

Allen, Water Resources Section, Iowa Department of 

Natural Resources, (written commun., May 2004) for 

the Maquoketa River profile for the downstream side of 

the Lake Delhi dam, and the upstream and downstream 

sides of County Road X21 and Marion Street bridges. 

The HWMs used to profile the May 23, 2004, flood in the 

Turkey and Maquoketa River Basins are listed in tables 

6–8 and are plotted by river mile in figures 6–15. Primary 

highways referred to in the report are shown in figures 

1–2; secondary roads are not shown.

Table 6. Elevation of high-water marks used in the May 2004 flood profile for the Turkey River, Iowa.

[HWM, high-water mark; NGVD 29, elevation data are referenced to the National Geodetic Vertical Datum of 1929; --, not determined]

Distance upstream 

from mouth of 

Turkey River

(river miles)

Site description

Downstream 

HWM

(feet above 

NGVD 29)

Upstream 

HWM

(feet above 

NGVD 29)

1.71 Iowa, Chicago, and Eastern railroad, east of Millville 616.28 619.44

5.24 U.S. Highway 52, north of Millville 627.90 628.55

12.96 County Roads C43 and X47/Osterdock Road, Osterdock 641.81 643.61

21.16 USGS gaging station 05412500, County Road C43/Jupiter Road, Garber 667.26 --

21.84 County Road C7X, between Elkport and Garber 668.42 668.70

33.79 Galaxy Road (abandoned), Motor 704.79 705.46

39.09 USGS gaging station 05412020, State Highway 13, south of Elkader 720.50 --

Table 7. Elevation of high-water marks used in the May 2004 flood profile for the Volga River, Iowa.

[HWM, high-water mark; NGVD 29, elevation data are referenced to the National Geodetic Vertical Datum of 1929; --, not determined]

Distance upstream 

from mouth of Volga 

River (river miles)

Site description

Downstream HWM

(feet above 

NGVD 29)

Upstream HWM

(feet above NGVD 29)

0.52 County Road X3C/Grandview Road, north of Elkport 671.13 671.76

9.33 USGS gaging station 05412400, County Road X21/Littleport 

Road, Littleport

698.98 --

Flood Profile 17
The May 2004 flood along the Turkey River is profiled from the Iowa, Chicago, and Eastern railroad (fig. 7) 

near the mouth upstream to State Highway 13 near Elkader 

(fig. 9). The 37-mi river reach that was profiled along the 

Turkey River is shown in figure 1, and the seven stream 

sites where HWMs were measured are listed in table 6. A 

low-water profile measured on September 22, 1992, (Eash 

and Koppensteiner, 1996) is shown for the river reach. The 

low-water profile was obtained for the purpose of indicating the range in stage along the stream and to define the 

low-water slope.

The May 2004 flood along the Volga River is profiled 

from County Road X3C near Elkport upstream to County 

Road X21 at Littleport (fig. 10). The 9-mi reach that was 

profiled along the Volga River is shown in figure 1, and the 

two stream sites where HWMs were measured are listed in 

table 7.

The May 2004 flood along the Maquoketa River is 

profiled from County Road D47 near Hopkinton (fig. 12) 

upstream to State Highway 187 near Arlington (fig. 15). 

The 52-mi river reach that was profiled along the Maquoketa River is shown in figure 2, and the 14 stream sites 

where HWMs were measured are listed in table 8.

Summary

Information on flood-peak and water-surface-elevation profiles is needed for the economical planning and 

safe design of bridges and other structures located along 

streams and for the effective management of flood plains. 

Data for major floods are needed to compute flood-peak 

discharges and calibrate water-surface-elevation profile 

models. This report was prepared in cooperation with the 

Iowa Department of Transportation and the Iowa Highway 

Research Board.

Severe flooding occurred on May 23, 2004, in the 

Turkey River Basin in Clayton County and in the Maquoketa River Basin in Delaware County following intense 

thunderstorms over northeast Iowa. Seventy-two hour 

rainfall recorded at Postville and Waucoma on May 23 

were 6.32 and 6.55 in., respectively. Unofficial rainfall 

Table 8. Elevation of high-water marks used in the May 2004 flood profile for the Maquoketa River, Iowa.

[HWM, high-water mark; NGVD 29, elevation data are referenced to the National Geodetic Vertical Datum of 1929; --, not determined]

Distance upstream 

from mouth of 

Maquoketa River 

(river miles)

Site description

Downstream HWM

(feet above 

NGVD 29)

Upstream HWM

(feet above 

NGVD 29)

92.17 County Road D47/Marion Street, southwest of Hopkinton 837.05 837.47

101.58 County Road X31/230th Avenue crossing Lake Delhi dam, 

southwest of Delhi

873.49 897.58

103.58 County Road X29/220th Avenue, southwest of Delhi 1898.1 --

109.40 County Road X21/240th Street, southeast of Manchester 904.67 906.03

113.25 USGS gaging station 05416900, U.S. Highway 20, south of 

Manchester

922.07 922.94

114.42 Marion Street, Manchester 926.29 930.12

114.76 State Highway 13/ West Main Street, Manchester 931.02 932.06

116.98 195th Street, northwest of Manchester 937.22 937.68

117.03 Quaker Mill Pond dam, northwest of Manchester 937.68 949.86

125.52 County Road C64/Richland Street, Dundee 981.66 982.59

127.82 Backbone State Park dam 996.03 1,003.46

131.32 Backbone State Park Road, near road leading to County Road 

C57/120th Street

1,016.06 21,016.14

139.73 State Highway 3, west of Strawberry Point 1,079.40 1,080.79

143.71 State Highway 187, southeast of Arlington 1,103.84 1,105.07

1Estimated flood elevation.

2High-water mark on stone shelter building located approximately 320 ft upstream of bridge.

18  Flood of May 23, 2004, in the Turkey and Maquoketa River Basins, Northeast Iowa
totals of 8 to 10 in. were reported in the Turkey River 

Basin. The peak discharge on May 23 at the Turkey River 

at Garber gaging station was 66,700 ft3/s (recurrence 

interval greater than 500 years) and is the largest flood 

on record in the Turkey River Basin. The timing of flood 

crests on the Turkey and Volga Rivers, and local tributaries, coincided to produce a record flood on the lower part 

of the Turkey River. Three large floods have occurred at 

the Turkey River at Garber gaging station in a 13-year 

period. Peak discharges of the floods of June 15, 1991, and 

May 17, 1999, were 49,900 ft3/s (recurrence interval about 

150 years) and 53,900 ft3/s (recurrence interval about 220 

years), respectively. The peak discharge on May 23 at the 

Maquoketa River at Manchester gaging station was 26,000 

ft3/s (recurrence interval about 100 years) and is the largest known flood in the upper part of the Maquoketa River 

Basin.

Acknowledgments

The author expresses his gratitude to the following: 

David Allen, Water Resources Section, Iowa Department 

of Natural Resources, for providing additional high-water 

marks for the May 23, 2004, flood along the Maquoketa 

River; Jim Whitman and Terry Morse, Iowa Department 

of Transportation, Tom Taylor, Clayton County Engineer’s 

Office, and Doug Dabroski, Delaware County Secondary Road Department, for providing elevation data for 

temporary bench marks at bridges; Harry Hillaker, State 

Climatologist, Iowa Department of Agriculture and Land 

Stewardship, for providing an isohyetal map of rainfall 

for the 72-hour period ending 7:00 a.m. on May 23, 2004; 

Bonnie Shepard, National Flood Insurance Program 

Bureau and Statistical Agent, Federal Emergency Management Agency, for providing private property damage 

claims for 10 counties in Iowa; and Dennis Harper, State 

Hazard Mitigation Officer, Iowa Homeland Security and 

Emergency Management Division, for providing public 

assistance project costs for 10 counties in Iowa. The author 

also expresses gratitude to the following U.S. Geological Survey employees: Myrna Gouw, Jason Smith, Greg 

Littin, and Aimee Donnelly for collecting field data for the 

determination of water-surface and bench-mark elevations 

listed in this report; and Kaylene Carney for obtaining 

newspaper articles for the compilation of flood-description 

information.

Literature Cited

Ballew, J.L., and Fischer, E.E., 2000, Floods of May 

17–20, 1999, in the Volga and Wapsipinicon River 

Basins, northeast Iowa: U.S. Geological Survey OpenFile Report 00–37, 36 p.

Dorman, Todd, and Haugen Dan, 2004, May 26, Waterloo 

Cedar-Falls Courier newspaper article.

Eash, D.A., 2001, Techniques for estimating flood-frequency discharges for streams in Iowa: U.S. Geological 

Survey Water-Resources Investigations Report 00–4233, 

88 p. [Available online at http://ia.water.usgs.gov/pubs/

reports/WRIR_00-4233.pdf]

Eash, D.A., 2005, Flood of June 4–5, 2002, in the Maquoketa River Basin, east-central Iowa: U.S. Geological 

Survey Open-File Report 2004–1250, 29 p. [Available 

online at http://pubs.usgs.gov/of/2004/1250/.]

Eash, D.A., and Koppensteiner, B.A., 1996, Floods of July 

12, 1972, March 19, 1979, and June 15, 1991, in the 

Turkey River Basin, northeast Iowa: U.S. Geological 

Survey Open-File Report 96–560, 55 p.

Federal Emergency Management Agency, 2004, Iowa 

severe storms, tornadoes, and flooding declared May 

25, 2004: Federal Emergency Management Agency 

Declared Disasters, accessed February 27, 2006, at 

http://www.fema.gov/news/event.fema?id=3023

Gravelle, Steve, 2004, May 24, Cedar Rapids Gazette 

newspaper article.

Harris, Bonnie, 2005, September 18, Des Moines Register 

newspaper article.

Hogan, Dick, 2004, May 25, Cedar Rapids Gazette newspaper article.

Horick, P.J., and Soenksen, P.J., 1989, Water resources of 

northeast Iowa: Iowa Department of Natural Resources 

Water Atlas 8, 133 p.

Huff, F.A., and Angel, J.R., 1992, Rainfall frequency atlas 

of the Midwest: Champaign, IL, Illinois State Water 

Survey, Bulletin 71, 141 p.

Interagency Advisory Committee on Water Data, 1982, 

Guidelines for determining flood flow frequency: 

Hydrology Subcommittee Bulletin 17B, 28 p. and 

appendixes.

Iowa Conservation Commission, 1979, Iowa’s low-head 

dams—their past, present, and future roles: Des Moines, 

Iowa, Iowa State Water Resources Research Institute 

Special Report no. 96, 312 p.

Literature Cited 19
Iowa Department of Agriculture and Land Stewardship, 

State Climatologist Office, 2004, Iowa climate review: 

Des Moines, Iowa, Monthly Summaries, v. 18, no. 5, 

22 p.

Iowa Geological Survey, 1944, Surface water resources of 

Iowa for the period October 1, 1940 to September 30, 

1942: Iowa City, Iowa, Iowa Geological Survey WaterSupply Bulletin no. 2, 222 p.

Iowa Natural Resources Council, 1958, An inventory of 

water resources and water problems, northeastern Iowa 

river basins: Des Moines, Iowa, Iowa Natural Resources 

Council Bulletin no. 7, 74 p.

Iowa Natural Resources Council, 1980, Turkey/Volga 

River flood of March 19, 1979: Des Moines, Iowa, 

25 p.

Jordan, Erin, 2004, May 24, Des Moines Register newspaper article.

Jordan, Erin, 2004, July 13, Des Moines Register newspaper article.

Jordan, Erin, 2005, February 10, Des Moines Register 

newspaper article.

Larimer, O.J., 1957, Drainage areas of Iowa streams: Iowa 

Highway Research Board Bulletin No. 7 (reprinted 

1974), 439 p.

Leys, Tony, 2004, May 24, Des Moines Register newspaper article.

Love, Orlan, 2004, May 26, Cedar Rapids Gazette newspaper article.

Palmer, Joel, and Heinselman, Karen, 2004, May 23, 

Waterloo Cedar-Falls Courier newspaper article.

Prior, J.C., 1991, Landforms of Iowa: Iowa City, Iowa 

Department of Natural Resources, University of Iowa 

Press, 153 p.

U.S. Department of Commerce, National Oceanic 

and Atmospheric Administration, and National Climatic Data Center, 2004a, National Climatic Data 

Center storm events, accessed February 27, 2006, 

at http://www4.ncdc.noaa.gov/cgi-win/wwcgi.

dll?wwEvent~storms (search terms: Iowa, 5/21/2004 to 

5/23/2004, flood).

U.S. Department of Commerce, National Oceanic and 

Atmospheric Administration, and National Climatic 

Data Center, 2004b, Climatological data, Iowa, May 

2004: Asheville, N.C., Monthly Summaries, v. 115, no. 

5, 44 p.

U.S. Department of Commerce, National Oceanic and 

Atmospheric Administration, and National Climatic 

Data Center, 2004c, Hourly precipitation data, Iowa, 

May 2004: Asheville, N.C., Monthly Summaries, v. 54, 

no. 5, 28 p.

U.S. Department of Commerce, National Oceanic and 

Atmospheric Administration, and National Weather 

Service, 2004a, Monthly report of rivers and flood conditions, Davenport, Iowa, Hydrologic Service Area, May 

2004: National Weather Service, NWS Form E–5, 5 p.

U.S. Department of Commerce, National Oceanic and 

Atmospheric Administration, and National Weather 

Service, 2004b, Monthly report of rivers and flood conditions, La Crosse, Iowa, Hydrologic Service Area, May 

2004: National Weather Service, NWS Form E–5, 1 p.

U.S. Geological Survey, 1964, Compilation of records of 

surface waters of the United States, October 1950 to 

September 1960, part 5, Hudson Bay and upper Mississippi River Basins: U.S. Geological Survey Water-Supply Paper 1728, 576 p.

20 Flood of May 23, 2004, in the Turkey and Maquoketa River Basins, Northeast Iowa
DISTANCE UPSTREAM FROM MOUTH OF TURKEY RIVER, IN MILES

ELEVATION, IN FEET ABOVE NGVD 29

0 10 20 30 40

740

720

700

680

660

640620

600

Bridge-deck elevation

Low-bridge-chord elevation

Flood of May 23, 2004

Flood of June 15, 1991Flood of March 19, 1979 (Iowa

Natural Resources Council, 1980)

Low water September 22, 1992

Locations indicated by these vertical lines are described in figures 7–9

Figure 6. Profile of the May 2004 flood for the Turkey River, Iowa; river miles 1.7 to 39.1.

Flood Profile 21
DISTANCE UPSTREAM FROM MOUTH OF TURKEY RIVER, IN MILES

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

670

665

660

655

650

645

640

635

630

625

620

615

610

605

600

595

590

Bridge-deck elevation

Low-bridge-chord elevation

Flood of May 23, 2004

Flood of June 15, 1991

Flood of March 19, 1979 (Iowa

Natural Resources Council, 1980)

Low water September 22, 1992

Iowa, Chicago, and 

Eastern railroad bridge

U.S. Hghway 52

9102-09SE

County Roads C43 & X47

9103-02NE

Mouth of Little Turkey River

Osterdock

ELEVATION, IN FEET ABOVE NGVD 29

Figure 7. Profile of the May 2004 flood for the Turkey River, Iowa; river miles 1.7 to 15.

22 Flood of May 23, 2004, in the Turkey and Maquoketa River Basins, Northeast Iowa
DISTANCE UPSTREAM FROM MOUTH OF TURKEY RIVER, IN MILES

15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

700

695

690

685

680

675

670

665

660

655

650

645

640

635

630

625

620

Bridge-deck elevation

Low-bridge-chord elevation

Flood of May 23, 2004

Flood of June 15, 1991

Flood of March 19, 1979 (Iowa

Natural Resources Council, 1980)

Low water September 22, 1992

September 22, 1992,

discharge 1,070 cubic feet per second

Flood peak May 23, 2004,

discharge 66,700 cubic feet per second

Flood peak May 17, 1999,

discharge 53,900 cubic feet per second

Flood peak March 19, 1979,

discharge 26,000 cubic feet per second

Garber Elkport

Flood peak June 15, 1991,discharge 49,900 cubic feet per second

USGS gaging station

05412500

County Road C43

9204-36NW

Mouth of Elk Creek

County Road C7X

9204-35NE

Mouth of Volga River

ELEVATION, IN FEET ABOVE NGVD 29

Figure 8. Profile of the May 2004 flood for the Turkey River, Iowa; river miles 15 to 30.

Flood Profile 23
DISTANCE UPSTREAM FROM MOUTH OF TURKEY RIVER, IN MILES

30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45

740

735

730

725

720

715

710

705

700

695

690

685

680

675

670

665

660

Bridge-deck elevation

Low-bridge-chord elevation

Flood of May 23, 2004

Flood of June 15, 1991

Flood of March 19, 1979 (Iowa

Natural Resources Council, 1980)

Low water September 22, 1992

Elkader

Flood peak May 23, 2004,

discharge 33,300 cubic feet per second

Flood peak June 15,1991,

discharge 38,300 cubic feet per second

September 22, 1992,

discharge approximately

960 cubic feet per second

GS gaging station US

05412020

State Highway 13

9305-26NW

Galaxy Road (abandoned)

9204-06SE

Dam below Bridge Street

9305-23SW

Mouth of Roberts Creek

ELEVATION, IN FEET ABOVE NGVD 29

Figure 9. Profile of the May 2004 flood for the Turkey River, Iowa; river miles 30 to 39.1.

24 Flood of May 23, 2004, in the Turkey and Maquoketa River Basins, Northeast Iowa
DISTANCE UPSTREAM FROM MOUTH OF VOLGA RIVER, IN MILES

0 1 2 3 4 5 6 7 8 9 10

710

705

700

695

690

685

680

675

670

665

660

655

650

645

640

635

630

Bridge-deck elevation

Low-bridge-chord elevation

Flood of May 23, 2004

Flood of May 17, 1999

Flood of June 15, 1991

Flood of March 19, 1979 (Iowa

Natural Resources Council, 1980)

Low water September 22, 1992

Littleport

Flood peak May 17, 1999,

discharge 30,000 cubic feet per second

Flood peak May 23, 2004,

discharge 21,000 cubic feet per second

Flood peak June 15, 1991,

discharge 13,500 cubic

feet per second

Flood peak March 19, 1979,

discharge 12,600 cubic

feet per second

September 22, 1992,

discharge approximately190 cubic feet per second

County Road X3C

9204-26SE

County Road X21

9205-25SE

ELEVATION, IN FEET ABOVE NGVD 29

Figure 10. Profile of the May 2004 flood for the Volga River, Iowa; river miles 0.4 to 9.3.

Flood Profile 25
Figure 11. Profile of the May 2004 flood for the Maquoketa River, Iowa; river miles 92.2 to 143.7

26  Flood of May 23, 2004, in the Turkey and Maquoketa River Basins, Northeast Iowa
DISTANCE UPSTREAM FROM MOUTH OF MAQUOKETA RIVER, IN MILES

90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105

910

905

900

895

890

885

880

875

870

865

860

855

850

845

840

835

830

825

820

815

810

Bridge-deck elevation

Low-bridge-chord elevation

County Road D47

8704-24NW

Mouth of Buck Creek

Mouth of Plum Creek

County Road X31

Lake Delhi dam

8804-30NE

County Road X29

8804-30NW

Flood of May 23, 2004

Flood of June 4, 2002

Low water November 10, 2004

Hopkinton

Lake Delhi

ELEVATION, IN FEET ABOVE NGVD 29

Figure 12. Profile of the May 2004 flood for the Maquoketa River, Iowa; river miles 92.2 to 105.

Flood Profile 27
DISTANCE UPSTREAM FROM MOUTH OF MAQUOKETA RIVER, IN MILES

105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120

970

965

960

955

950

945

940

935

930

925

920

915

910

905

900

895

890

885

880

875

870

Bridge-deck elevation

Low-bridge-chord elevation

Flood of May 23, 2004

Flood of June 4, 2002

Low water November 10, 2004

Manchester

November 10, 2004,

discharge 68 cubic feet per second

Flood peak June 4, 2002,

discharge 10,800 cubic feet per second

Flood peak May 23, 2004,

discharge 26,000 cubic feet per second

ELEVATION, IN FEET ABOVE NGVD 29

County Road X21

8805-15NE

USGS gaging station

05416900

U.S. Highway 20

8905-33SW

Dam 8905-32NE

Marion Street

State Highway 13

8905-32NW

Mouth of Coffin Creek

Mouth of Honey Creek

195th Street

Quaker Mill Pond dam

8905-19NE

Figure 13. Profile of the May 2004 flood for the Maquoketa River, Iowa; river miles 105 to 120.

28  Flood of May 23, 2004, in the Turkey and Maquoketa River Basins, Northeast Iowa
DISTANCE UPSTREAM FROM MOUTH OF MAQUOKETA RIVER, IN MILES

120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135

995

990

985

980

975

970

965

960

955

950

1050

1045

1040

1035

1030

1025

1020

1015

1010

1005

1000

Bridge-deck elevation

Low-bridge-chord elevation

Flood of May 23, 2004

Low water November 10, 2004

Dundee Backbone State Park

ELEVATION, IN FEET ABOVE NGVD 29

County Road C64

9006-27SW

Backbone State Park dam

9006-22NE

Backbone State Park Road

9006-09SW

Mouth of South Fork

Maquoketa River

Figure 14. Profile of the May 2004 flood for the Maquoketa River, Iowa; river miles 120 to 135.

Flood Profile 29
DISTANCE UPSTREAM FROM MOUTH OF MAQUOKETA RIVER, IN MILES

135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150

1130

1125

1120

1115

1110

1105

1100

1095

1090

1085

1080

1075

1070

1065

1060

1055

1050

1045

1040

1035

1030

Bridge-deck elevation

State Highway 3

9107-24NE

State Highway 187

9107-02SW

Low-bridge-chord elevation

Flood of May 23, 2004

Low water November 10, 2004

ELEVATION, IN FEET ABOVE NGVD 29

Figure 15. Profile of the May 2004 flood for the Maquoketa River, Iowa; river miles 135 to 143.7.

30 Flood of May 23, 2004, in the Turkey and Maquoketa River Basins, Northeast Iowa
Appendix

Appendix 31
Appendix. Temporary Bench Marks and Reference Points

To facilitate measuring and referencing the highwater marks (HWMs) used in the flood profiles to a 

common datum, temporary bench marks (TBMs) and 

reference points (RPs) were found or established by the 

U.S. Geological Survey (USGS) at bridges and dams 

along the profiled river reaches. All TBM and RP elevations listed in this tabulation are referenced to the National 

Geodetic Vertical Datum of 1929. Tables 6–8 list the 23 

bridge and dam sites where the USGS measured HWMs 

for the May 2004 flood profile. Of these 23 sites, TBMs 

are presented in this appendix for 20 of the sites and RPs 

are presented for 14 of the sites (note: more than one TBM 

or RP are listed for some sites). For 5 of the 20 sites listed 

in this appendix, TBMs and corresponding elevations were 

established by other agencies and these agencies are noted 

in the descriptions of the TBMs. The USGS established 

TBMs at 15 sites and RPs at 14 sites during 2002–04; with 

the exception of the first four sites listed for the Turkey 

River for which TBMs and RPs were established by the 

USGS prior to 1993 and the Volga River at Littleport site 

for which a bench mark was established in 1964. TBMs or 

reference marks established at USGS gaging stations are 

identified in this tabulation with an RM number. TBM and 

RP elevations established by the USGS were determined 

from differential leveling, with the exception of TBMs at 

seven sites, where elevations were determined from postprocessed differential positioning using a global positioning system (GPS). Elevations determined using GPS are 

noted in the TBM and RP descriptions. Level lines or GPS 

networks, used to establish the third-order accuracy of the 

15 TBMs established by the USGS shown herein, were 

surveyed or configured from bench marks established and 

adjusted by the Geography Discipline of the USGS and 

National Geodetic Survey. Errors of closure in the USGS 

level work were adjusted along level lines to balance TBM 

and RP elevations. Specific GPS-network and satelliteconstellation configurations, equivalent hours of data collection with multiple GPS receivers, and post-processing 

quality controls were used to control the effects of error in 

GPS-derived elevations.

The TBMs and RPs are designated by an index number or legal description derived from their respective locations using Public Land Survey System coordinates (township, range, section). Within the section, the quarter section 

in which the TBM or RP is located is designated by NE, 

SE, NW, and SW. For example, 9102-12 SW refers to a 

location in Township 91 North, Range 2 West, southwest 

quarter of section 12. A number in parentheses following 

the quarter-section designation indicates the number of the 

TBM or RP in that particular quarter section. The index 

number serves to describe the legal description of the mark 

without further reference in the body of the description. 

The physical location of the TBM on a bridge dictates the 

appropriate legal description. An RP, and any additional 

TBMs, are listed with the related TBM and are identified 

by the same legal description though, at times, they are in 

a different section, range, or township as determined by 

upstream or downstream location.

Standard marks, such as squares, crosses, or marks 

were chiseled or filed on concrete or metal; or existing 

bolts on bridges were used as TBMs or RPs. RPs are 

distinguished from TBMs by the notation “(REFERENCE 

POINT)” following the legal description. RPs were established to permit water-surface elevations to be determined 

by use of a tape and weight. The terms “right” and “left” in 

the descriptions are determined as viewed while facing in 

the downstream direction.

The TBMs and RPs are listed in the downstream to 

upstream order with respect to their correspondence to 

bridges or dams across the Turkey, Volga, and Maquoketa Rivers. The user of this information is cautioned that 

TBMs and RPs listed herein might have been disturbed, 

destroyed, or moved since elevations were established. It 

is the responsibility of the user to determine the condition 

and the suitability of the TBM or RP.

Turkey River

9102-12 SW (1)—Approximately 2.4 mi east of Millville 

at Iowa, Chicago, and Eastern railroad bridge over Turkey 

River, on right upstream bridge footing, 5.1 ft lower than 

wood plank, most streamward and downstream bolt; top of 

bolt.

Elevation 616.89 ft.

9102-12 SW (2)—(REFERENCE POINT) Approximately 

2.4 mi east of Millville at Iowa, Chicago, and Eastern railroad bridge over Turkey River, on third truss member from 

right upstream bridge abutment, 6 in. lower than wood 

deck; chiseled arrow.

Elevation 621.43 ft.

9102-09 SE (1)—At north of Millville, on U.S. Highway 

52 bridge over Turkey River, on right upstream wing32 Flood of May 23, 2004, in the Turkey and Maquoketa River Basins, Northeast Iowa
wall; National Geodetic Survey (U.S. Coast & Geodetic 

Survey) bench mark disk stamped “B179-1970.” Elevation 

obtained from National Geodetic Survey.

Elevation 634.822 ft.

9102-09 SE (2)­—(REFERENCE POINT) At north of 

Millville, on U.S. Highway 52 bridge over Turkey River, 

on downstream curb between 13th and 14th guardrail posts 

from right end of bridge; chiseled square.

Elevation 634.78 ft.

9103-02 NE (1)—At Osterdock, on County Roads C43 

and X47/Osterdock Road bridge over Turkey River, on 

right upstream concrete curb; brass tablet stamped “1957.” 

Elevation obtained from Clayton County Engineer (revised 

elevation).

Elevation 647.94 ft.

9103-02 NE (2)—(REFERENCE POINT) At Osterdock, 

on County Roads C43 and X47/Osterdock Road bridge 

over Turkey River, on downstream curb between 31st 

and 32nd guardrail posts from left end of bridge; chiseled 

arrow.

Elevation 648.88 ft.

9204-36 NW (1)—At Garber, on County Road C43/Jupiter 

Road bridge over Turkey River, on center of left upstream 

guardrail; Iowa Department of Transportation bench mark. 

(RM 10)

Elevation 672.10 ft.

9204-35 NE (1)—Between Elkport and Garber, on County 

Road C7X bridge over Turkey River, on right downstream 

wingwall; Iowa Department of Transportation bench mark. 

Elevation obtained from Clayton County Engineer.

Elevation 677.27 ft.

9204-35 NE (2)—(REFERENCE POINT) Between Elkport and Garber, on County Road C7X bridge over Turkey 

River, on downstream concrete barrier guardrail at fourth 

section from right end of bridge; chiseled square.

Elevation 679.40 ft.

9305-26 NW (1)—Approximately 0.5 mi south of Elkader, 

on State Highway 13 bridge over Turkey River, on right 

upstream wingwall; Iowa Department of Transportation 

bench mark. (RM 1)

Elevation 732.88 ft.

9305-26 NW (2)—Approximately 0.5 mi south of Elkader, 

on State Highway 13 bridge over Turkey River, on left 

upstream wingwall; Iowa Department of Transportation 

bench mark. (RM 2)

Elevation 731.50 ft.

Volga River

9205-25 SE (1)—At Littleport, on County Road X21/

Littleport Road bridge over Volga River, on left upstream 

wingwall curb; U.S. Geological Survey brass tablet 

stamped “15 JRE 1964 708.”

Elevation 708.254 ft.

Maquoketa River

8704-24 NW (1)—Approximately 0.5 mi southwest of 

Hopkinton, on County Road D47/Marion Street bridge 

over southern channel of Maquoketa River, on left downstream end of sidewalk concrete barrier wall; Delaware 

County bench mark. Elevation of bench mark on bridge 

surveyed by USGS from elevation southwest of bridge 

provided by Delaware County Engineer’s Office. 

Elevation 846.90 ft

8704-24 NW (2)—(REFERENCE POINT) Approximately 

0.5 mi southwest of Hopkinton, on County Road D47/

Marion Street bridge over southern channel of Maquoketa River, on downstream side of cyclone fence at 12th 

fence post from right downstream end of bridge; edge of 

concrete sidewalk. 

Elevation 844.83 ft

8804-30 NE (1)—Approximately 1.5 mi southwest of 

Delhi, on County Road X31/230th Avenue crossing Lake 

Delhi dam on Maquoketa River, on end of right downstream wingwall; chiseled cross. Elevation determined 

using GPS.

Elevation 907.37 ft

8804-30 NW (1)—Approximately 2 mi southwest of 

Delhi, on County Road X29/220th Avenue bridge over 

Lake Delhi, on corner of wingwall near guardrail at left 

downstream end of bridge; chiseled square. Elevation 

determined using GPS.

Elevation 906.33 ft

Appendix 33
8804-30 NW (2)—(REFERENCE POINT) Approximately 

2 mi southwest of Delhi, on County Road X29/220th Avenue bridge over Lake Delhi, on metal guardrail between 

11th and 12th guardrail posts from right downstream end 

of bridge; three filed marks. Elevation determined using 

GPS.

Elevation 911.45 ft

8805-15 NE (1)—Approximately 4 mi southeast of Manchester, on County Road X21/240th Street bridge over 

Maquoketa River, on corner of wingwall near guardrail at 

right upstream end of bridge; chiseled square. Elevation 

determined using GPS.

Elevation 915.58 ft

8805-15 NE (2)—(REFERENCE POINT) Approximately 

4 mi southeast of Manchester, on County Road X21/240th 

Street bridge over Maquoketa River, on metal guardrail 

behind 3rd drain from right downstream end of bridge; 

three filed marks. Elevation determined using GPS.

Elevation 917.32 ft

8905-33 SW (1)—Approximately 0.5 mi south of Manchester, on eastbound lane of U.S. Highway 20 bridge over 

Maquoketa River (downstream bridge), on left upstream 

abutment; Iowa Department of Transportation bench mark. 

(RM 1)

Elevation 938.14 ft

8905-33 SW (2)—Approximately 0.5 mi south of Manchester, on eastbound lane of U.S. Highway 20 bridge over 

Maquoketa River (downstream bridge), on left downstream 

abutment; chiseled square. (RM 2)

Elevation 938.34 ft

8905-32 NE (1)—At Manchester, on Marion Street bridge 

over Maquoketa River, at left downstream end of bridge 

underneath Marion Street bridge sign; chiseled cross. 

Elevation 939.00 ft

8905-32 NE (2)—At Manchester, on Marion Street bridge 

over Maquoketa River, on retaining wall at left upstream 

abutment; chiseled cross. 

Elevation 938.93 ft

8905-32 NE (3)—( REFERENCE POINT) At Manchester, 

on Marion Street bridge over Maquoketa River, beneath 

metal box attached to downstream guardrail; edge of concrete sidewalk. 

Elevation 940.72 ft

8905-32 NW (1)—At Manchester, on State Highway 

13/West Main Street bridge over Maquoketa River, on left 

downstream end of sidewalk concrete barrier wall at end of 

metal rail; Iowa Department of Transportation bench mark. 

Elevation obtained from Iowa Department of Transportation.

Elevation 944.30 ft

8905-32 NW (2)—(REFERENCE POINT) At Manchester, on State Highway 13/West Main Street bridge over 

Maquoketa River, on downstream side of cyclone fence at 

10th fence post from left downstream end of bridge; edge 

of concrete sidewalk.

Elevation 945.08 ft

8905-19 NE (1)—Approximately 0.5 mi northwest of 

Manchester, on 195th Street bridge over Maquoketa River, 

on right upstream end of lower wingwall; chiseled square. 

Elevation determined using GPS.

Elevation 943.11 ft

9006-27 SW (1)—At west edge of Dundee, on County 

Road C64/Richland Street bridge over Maquoketa River, 

on right downstream wingwall; chiseled square. Elevation of bench mark on bridge surveyed by USGS from 

elevation west of bridge provided by Delaware County 

Engineer’s Office.

Elevation 992.57 ft

9006-27 SW (2)—(REFERENCE POINT) At west edge of 

Dundee, on County Road C64/Richland Street bridge over 

Maquoketa River, on guardrail at right of 10th guardrail 

post from left downstream end of bridge; filed arrow. 

Elevation 994.90 ft

9006-22 NE (1)—At Backbone State Park, on southeast 

dam of two dams across Maquoketa River, below cyclone 

fence on downstream end of upper horizontal concrete 

structure on left end of dam; chiseled square. Elevation 

determined using GPS.

Elevation 1,007.34 ft

9006-22 NE (2)—(REFERENCE POINT) At Backbone 

State Park, on southeast dam of two dams across Maquoketa River, below cyclone fence on upstream end of upper 

horizontal concrete structure on left end of dam; most 

upstream edge of upper horizontal concrete surface. Elevation determined using GPS.

Elevation 1,007.48 ft

34 Flood of May 23, 2004, in the Turkey and Maquoketa River Basins, Northeast Iowa
9006-22 NE (3)—(REFERENCE POINT) At Backbone 

State Park, on southeast dam of two dams across Maquoketa River, behind cyclone fence post on upstream end 

of lower horizontal concrete structure on left end of dam; 

most upstream edge of lower horizontal concrete surface. 

Elevation determined using GPS.

Elevation 996.08 ft

9006-09 SW (1)—At Backbone State Park, on Backbone 

State Park Road bridge across Maquoketa River near 

road leading to County Road C57/120th Street, on right 

downstream wingwall; Iowa Department of Transportation 

bench mark. Elevation determined using GPS.

Elevation 1,010.28 ft

9006-09 SW (2)—(REFERENCE POINT) At Backbone 

State Park, on Backbone State Park Road bridge across 

Maquoketa River near road leading to County Road C57/

120th Street, on downstream concrete barrier wall about 

1 ft right of center of concrete sections; chiseled square. 

Elevation determined using GPS.

Elevation 1,010.27 ft

9107-24 NE (1)—Approximately 3.5 mi west of Strawberry Point, on State Highway 3 bridge across Maquoketa 

River, on left downstream lower wingwall; Iowa Department of Transportation bench mark. Elevation obtained 

from Iowa Department of Transportation.

Elevation 1,088.42 ft

9107-24 NE (2)—(REFERENCE POINT) Approximately 

3.5 mi west of Strawberry Point, on State Highway 3 

bridge across Maquoketa River, on outer concrete platform 

behind 8th guardrail post from left downstream end of 

bridge; chiseled square.

Elevation 1,089.44 ft

9107-02 SW (1)—Approximately 2.25 mi southeast of 

Arlington, on State Highway 187 bridge across Maquoketa 

River, on left downstream wingwall; Iowa Department of 

Transportation bench mark. Elevation determined using 

GPS.

Elevation 1,109.99 ft

9107-02 SW (2)—(REFERENCE POINT) Approximately 

2.25 mi southeast of Arlington, on State Highway 187 

bridge across Maquoketa River, on outer concrete platform 

behind 3rd drain from right downstream end of bridge; 

chiseled square. Elevation determined using GPS.

Elevation 1,108.37 ft

Appendix 35
Prepared by the Iowa District office:

U.S. Geological Survey, WRD

Room 269, Federal Building

P.O. Box 1230

400 South Clinton Street

Iowa City, IA 52244

This publication is available online at URL:

http://pubs.water.usgs.gov/ofr20061067

Information regarding the water resources in Iowa is available at URL:

http://ia.water.usgs.gov
Printed on recycled paper

Eash, D.A..—Flood of May 23, 2004, in the Turkey and Maquoketa River Basins, Northeast Iowa—Open-File Report 2006–1067