U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2015–5129

Prepared in cooperation with the Iowa Department of Natural Resources

Simulation of Daily Streamflow for Nine River Basins in 

Eastern Iowa Using the Precipitation-Runoff Modeling 

System
Cover. Turkey River at Elkader, Iowa, 2014 (front cover); Maquoketa River near Green Island, Iowa, 

2015 (upper, back cover); and Wapsipinicon River at Oxford Mills, Iowa, 2014 (lower, back cover). 

Photographs by U.S. Geological Survey, Iowa Water Science Center.
Simulation of Daily Streamflow for Nine 

River Basins in Eastern Iowa Using the 

Precipitation-Runoff Modeling System 

By Adel E. Haj, Daniel E. Christiansen, and Kasey J. Hutchinson

Prepared in cooperation with the Iowa Department of Natural Resources

Scientific Investigations Report 2015–5129

U.S. Department of the Interior

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

SALLY JEWELL, Secretary

U.S. Geological Survey

Suzette M. Kimball, Acting Director

U.S. Geological Survey, Reston, Virginia: 2015

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as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner.

Suggested citation:

Haj, A.E., Christiansen, D.E., and Hutchinson, K.J., 2015, Simulation of daily streamflow for nine river basins in eastern Iowa using the Precipitation-Runoff Modeling System: U.S. Geological Survey Scientific Investigations Report 

2015–5129, 29 p., http://dx.doi.org/10.3133/sir20155129.

ISSN 2328-0328 (online)
iii

Contents

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

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

Purpose and Scope ..............................................................................................................................2

Description of Study Areas .................................................................................................................2

Model Development ......................................................................................................................................8

Delineation and Parameterization of Spatial Features...................................................................8

Model Input and Measured Data.....................................................................................................10

Model Calibration, Validation, and Evaluation ...............................................................................10

Simulation of Daily Streamflow for Nine River Basins in Eastern Iowa Using the

Precipitation-Runoff Modeling System ......................................................................................21

Model Limitations.........................................................................................................................................26

Summary........................................................................................................................................................27

References Cited..........................................................................................................................................27

Figures

1. Map showing landform regions for Precipitation-Runoff Modeling System 

models of nine river basins in eastern Iowa ............................................................................3

2. Map showing simulated stream segments and U.S. Geological Survey

streamflow-gaging stations providing measured data for Precipitation-Runoff

Modeling System models of nine river basins in eastern Iowa............................................4

3. Schematic diagram of a basin and its meteorological inputs simulated by the

Precipitation-Runoff Modeling System.....................................................................................9

4. Map showing National Oceanic and Atmospheric Administration’s National

Weather Service Cooperative Observer Program meteorological stations and

hydrologic response units used in the Precipitation-Runoff Modeling System

models or nine river basins in eastern Iowa..........................................................................11

5. Graphs showing a comparison of measured and simulated flow at selected 

U.S. Geological Survey streamflow-gaging stations used in calibrating

Precipitation-Runoff Modeling System models of nine river basins in eastern 

Iowa, water years 2002–12........................................................................................................22
iv

Tables

1. U.S. Geological Survey streamflow-gaging stations used for input, calibrating, and

validating the Precipitation-Runoff Modeling System models of nine river basins in

eastern Iowa..................................................................................................................................5

2. National Oceanic and Atmospheric Administration’s National Weather Service

Cooperative Observer Program meteorological stations used in the

Precipitation-Runoff Modeling System models of nine river basins in eastern 

Iowa ..............................................................................................................................................12

3. Nash-Sutcliffe efficiency, coefficient of determination, percent bias, and root 

mean square error-observation standard deviation ratio statistic values at U.S.

Geological Survey streamflow-gaging stations used for calibration or validation

periods in the Precipitation-Runoff Modeling System models of nine river basins 

in eastern Iowa ...........................................................................................................................16

4. Calibrated parameters and Let Us Calibrate calibration steps for the

Precipitation-Runoff Modeling System models of nine river basins in eastern 

Iowa ..............................................................................................................................................19

Conversion Factors

Inch/Pound to International System of Units

Multiply By To obtain

Length

inch (in.) 25.4 millimeter (mm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

square mile (mi2

) 2.590 square kilometer (km2) 

Volume

cubic foot (ft3

) 0.02832 cubic meter (m3) 

Flow rate

cubic foot per second (ft3

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

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).

The water year (WY) begins October 1 and ends September 30 of the following year. The WY is 

designated by the calendar year in which it ends; for example, WY 2014 begins on October 1, 

2013, and ends on September 30, 2014.
Simulation of Daily Streamflow for Nine River Basins in 

Eastern Iowa Using the Precipitation-Runoff Modeling 

System 

By Adel E. Haj, Daniel E. Christiansen, and Kasey J. Hutchinson

Abstract

The U.S. Geological Survey, in cooperation with the 

Iowa Department of Natural Resources, constructed Precipitation-Runoff Modeling System models to estimate daily 

streamflow for nine river basins in eastern Iowa that drain 

into the Mississippi River. The models are part of a suite of 

methods for estimating daily streamflow at ungaged sites. The 

Precipitation-Runoff Modeling System is a deterministic, distributed-parameter, physical-process-based modeling system 

developed to evaluate the response of streamflow and general 

drainage basin hydrology to various combinations of climate 

and land use. Calibration and validation periods used in each 

basin mostly were October 1, 2002, through September 30, 

2012, but differed depending on the period of record available 

for daily mean streamflow measurements at U.S. Geological 

Survey streamflow-gaging stations. 

A geographic information system tool was used to 

delineate each basin and estimate values for model parameters 

based on basin physical and geographical features. A U.S. 

Geological Survey auto-calibration tool that uses a shuffled 

complex evolution algorithm was used for initial calibration, and then manual modifications were made to parameter 

values to complete the calibration of each basin model. The 

main objective of the calibration was to match daily discharge 

values of simulated streamflow to measured daily discharge 

values. 

The accuracy of Precipitation-Runoff Modeling System 

model streamflow estimates of nine river basins in eastern 

Iowa as compared to measured values at U.S. Geological 

Survey streamflow-gaging stations varied. The PrecipitationRunoff Modeling System models of nine river basins in eastern Iowa were satisfactory at estimating daily streamflow at 

57 of the 79 calibration sites and 13 of the 14 validation sites 

based on statistical results. Unsatisfactory performance can be 

contributed to several factors: (1) low flow, no flow, and flashy 

flow conditions in headwater subbasins having a small drainage area; (2) poor representation of the groundwater and storage components of flow within a basin; (3) lack of accounting 

for basin withdrawals and water use; and (4) the availability 

and accuracy of meteorological input data. The PrecipitationRunoff Modeling System models of nine river basins in 

eastern Iowa will provide water-resource managers with a 

consistent and documented method for estimating streamflow 

at ungaged sites and aid in environmental studies, hydraulic 

design, water management, and water-quality projects.

Introduction

The U.S. Geological Survey (USGS), in cooperation with 

State, county, municipal, and other Federal agencies, collects a 

large amount of data pertaining to the water resources of Iowa 

each year. These data constitute a valuable database for developing an improved understanding of State water resources. 

Surface-water data for Iowa include records of stage, discharge, and water quality of streams and records of stage of 

lakes and reservoirs. Iowa has 71,000 miles (mi) of rivers 

and streams (Iowa Department of Natural Resources, 2000), 

and measurements collected from USGS streamflow-gaging 

stations on those streams (gaged sites) only account for a very 

narrow representation of the surface-water flow in the State. 

There is a strong need by water-resource managers of the Iowa 

Department of Natural Resources (IDNR) for a consistent and 

documented method for providing streamflow estimates in 

Iowa at locations where no USGS streamflow-gaging station is 

present (ungaged sites). Streamflow estimates at ungaged sites 

would aid water-resource managers in environmental studies, hydraulic design, water management, and water-quality 

projects. 

The USGS maintains about 149 real-time streamflowgaging stations in Iowa where daily mean streamflow information is available (U.S. Geological Survey, 2014). This 

streamflow information provides the basis for understanding 

the hydrologic characteristics of drainage basins (basins), and, 

in combination with water-quality information collected at a 

monthly time step at 75 locations across the State by State and 

Federal agencies, aids in the understanding of risks imposed 

on human and ecosystem health. Because the information collected at gaged sites is site specific, the ability to confidently 
2 Simulation of Daily Streamflow for Nine River Basins in Eastern Iowa Using the Precipitation-Runoff Modeling System 

use these data to infer information at ungaged sites within a 

basin for adaptive management and decisions can be limited. 

Hydrological models are one tool that can be used to 

overcome the lack of hydrologic information at ungaged sites 

in eastern Iowa (Christiansen, 2012). Precipitation-Runoff 

Modeling System (PRMS) models (Leavesley and others, 

1983; Markstrom and others, 2008; Markstrom and others, 

2015) were constructed, in cooperation with the IDNR, for 

nine river basins in eastern Iowa as part of an ongoing research 

project to examine methods of estimating daily streamflow at 

gaged and ungaged sites. Hydrological models can be combined with other predictive methods and techniques, such as 

the Flow Duration Curve Transfer and the Flow Anywhere 

methods (Linhart and others, 2013), to provide a comprehensive approach in developing near real-time streamflow 

estimates. 

Purpose and Scope

This report describes the use of the USGS PRMS 

(Leavesley and others, 1983; Markstrom and others, 2008; 

Markstrom and others, 2015) for simulating daily streamflow 

in nine eastern Iowa River basins draining into the Mississippi 

River. The construction, calibration, and evaluation of PRMS 

models of nine river basins in eastern Iowa to simulate daily 

streamflow at gaged and ungaged sites are described. Model 

performance is assessed to determine the ability of PRMS to 

estimate streamflow and, thus, the suitability for the model to 

serve as part of a suite of methods for estimating daily streamflow at ungaged sites. Model limitations are investigated and 

described. 

Description of Study Areas

The PRMS models were constructed for a total of nine 

river basins in eastern Iowa that are tributaries to the Mississippi River: Upper Iowa River Basin, Yellow River Basin, Turkey River Basin, Maquoketa River Basin, Wapsipinicon River 

Basin, Iowa River Basin, Skunk River Basin, Des Moines 

River Basin, and Fox River Basin (figs. 1 and 2). Although the 

percentage varies, all basins are dominated by agriculture in 

the form of corn and soybeans (U.S. Department of Agriculture, 2014). There are livestock operations (including beef and 

dairy cattle, hogs, sheep, and poultry) in varying amounts in 

each of the nine river basins in eastern Iowa. In addition, tile 

drainage is extensive throughout each basin to enhance crop 

production by removing excess water from the soil. The eastern part of the State spans seven of Iowa’s landform regions, 

and each has a characteristic topography and glacial history 

(Prior and others, 2009; Prior, 1991) (fig. 1). 

The first of these nine basins in eastern Iowa, the 

Upper Iowa River Basin, is in northeast Iowa, drains about 

1,005 square miles (mi2), and extends from its headwaters 

in Mower County, Minnesota, to the Mississippi River in 

northeast Allamakee County, Iowa (figs. 1 and 2). The Upper 

Iowa River Basin is in an area of the State characterized by 

rugged hills, steep topography, a complex network of springs, 

and diverse land use. Most of the Upper Iowa River Basin is 

within the Paleozoic Plateau landform region; the western part 

of the Upper Iowa River Basin is within the Iowan Surface 

landform region (fig. 1). Three USGS streamflow-gaging stations in the Upper Iowa River Basin were used in this study 

(table 1; fig. 2). 

The Yellow River Basin originates in southwestern Winneshiek County, northeast Iowa, and drains about 240 mi2

before its confluence with the Mississippi River in Allamakee 

County, Iowa (fig. 1). The Yellow River Basin is within the 

Paleozoic Plateau (figs. 1 and 2). The Yellow River Basin is 

mainly forest or agricultural land with little urban development (Iowa Department of Natural Resources, 2009). One 

USGS streamflow-gaging station in the Yellow River Basin 

was used in this study (table 1; fig. 2).

The Turkey River Basin originates in Howard County, 

northeast Iowa, and drains about 1,685 mi2 into the Mississippi 

River in Clayton County, Iowa (figs. 1 and 2). The upper part 

of the Turkey River Basin is within the Iowan Surface, and the 

lower part lies within the Paleozoic Plateau (fig. 1). Six USGS 

streamflow-gaging stations in the Turkey River Basin were 

used in this study (table 1; fig. 2).

The Maquoketa River Basin drains about 1,880 mi2 in 

northeast Iowa, originates in Fayette County, Iowa, and flows 

southeast to the Mississippi River in Jackson County, Iowa 

(figs. 1 and 2). The Maquoketa River Basin consists of the 

Iowan Surface and East-Central Iowa Drift Plain landform 

regions, and a small part in the northeast extends into the 

Paleozoic Plateau (fig. 1). Three USGS streamflow-gaging 

stations in the Maquoketa River Basin were used in this study 

(table 1; fig. 2). 

The Wapsipinicon River Basin drains 2,540 mi2, originates in Mower County, southeastern Minnesota, and extends 

about 225 mi southeast to its confluence with the Mississippi 

River (figs. 1 and 2). Most of the Wapsipinicon River Basin 

lies within the Iowan Surface, but small parts cross into the 

East-Central Iowa Drift Plain and Southern Iowa Drift Plain 

landform region in the eastern part of the Wapsipinicon River 

Basin near the outlet (fig. 1). Seven USGS streamflow-gaging 

stations in the Wapsipinicon River Basin were used in this 

study (table 1; fig. 2).

The Iowa River Basin drains about 12,640 mi2

 and 

extends from its headwaters in southern Minnesota to its outlet 

in Louisa County, southern Iowa (fig. 1). The Cedar River 

is the largest tributary to the Iowa River and drains about 

7,815 mi2 before its confluence. The Iowa River Basin is the 

second largest basin in Iowa that extends into the Des Moines 

Lobe landform region in the northwest part, the Iowan Surface 

in the central and eastern parts, and the Southern Iowa Drift 

Plain and the Iowa-Cedar Lowland in the southern part of the 

basin (fig. 1). Cedar Rapids, Waterloo, and Iowa City, Iowa, 

are the primary urban centers within the Iowa River Basin. A 

total of 33 USGS streamflow-gaging stations in the Iowa River 

Basin were used in this study (table 1; fig. 2).
Introduction 3

Wapsipinicon River

Fox River

Skunk River

Turkey River

Racoon River

Maquoketa River

Cedar River

Yellow River

Upper Iowa 

River

Iowa River

Mississippi River

Des Moines River

Ames

Newton

Marion

Austin

Ottumwa

Waterloo

Iowa

City Des Moines

Fort 

Dodge

Mason City

Cedar Falls

Cedar Rapids

Keokuk

IOWA

ILLINOIS

MISSOURI

MINNESOTA

NEBRASKA

SOUTH DAKOTA

WISCONSIN

96° 95° 94° 93° 92° 91° 90°

44°

43°

42°

41°

0 40

40

80 MILES

0 80 KILOMETERS

LINN

SAC

LEE

CLARK

SCOTLAND

POLK

TAMA

CLAY

IOWA

KOSSUTH

STORY

JASPER

ADAIR

CLAYTON

CLINTON

BENTON

BUTLER

FAYETTE

JONES

CEDAR

DALLAS

WRIGHT

SCOTT

FLOYD

DAVIS

BOONE

WEBSTER

CARROLL

HARDIN

MARION

WARREN

GUTHRIE

KEOKUK

JACKSON

GREENE

FRANKLIN

UNION LUCAS

JOHNSON

HENRY

DUBUQUE

WORTH

CALHOUN GRUNDY

MARSHALL

CLARKE

HANCOCK

HAMILTON

MADISON

MAHASKA

LOUISA

ALLAMAKEE

PALO ALTO

BREMER

DELAWARE

HOWARD MITCHELL

BUCHANAN

MONROE

EMMET

POWESHIEK

WAPELLO

BUENA VISTA

BLACK 

HAWK

AUDUBON

POCAHONTAS

WASHINGTON

JEFFERSON

VAN BUREN

CHICKASAW

HUMBOLDT

CERRO GORDO

APPANOOSE

MUSCATINE

DICKINSON WINNEBAGO

DES MOINES

WINNESHIEK

MARTIN

FILLMORE

MOWER

NOBLES

MURRAY

JACKSON FARIBAULT

FREEBORN

HOUSTON

STEELE DODGE COTTONWOOD

LYON

PIPESTONE

Basin boundary—Precipitation-Runoff 

Modeling System

Iowa landform regions

Des Moines Lobe

East-Central Iowa Drift Plain

Iowa-Cedar Lowland

Iowan Surface

Northwest Iowa Plains

Paleozoic Plateau

Southern Iowa Drift Plain

EXPLANATION

Base from U.S. Geological Survey digital data, 1: 2,000,000, 1979

Universal Transverse Mercator projection, zone 15

North American Datum of 1983 (NAD 83)

Landform regions from Prior and others, 2009

Figure 1. Landform regions for Precipitation-Runoff Modeling System models of nine river basins in eastern Iowa.
4 Simulation of Daily Streamflow for Nine River Basins in Eastern Iowa Using the Precipitation-Runoff Modeling System 

#

#

#

#

#

#

# #

##

#

#

#

#

#

#

*#

*#

*#

#

#

#

##

#

#

#

#

#

# #*#*####

# #

#

# #

#

##

#

#

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#

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#

*#

*#

*#

###

#

#

# #

#

#

#

#

##

#

#

#

#*#

*#

#

#

#

#

# # *##*#*#

#

#

##

#

#

*## *#

#

*#

# *#

#

IOWA

ILLINOIS

MISSOURI

MINNESOTA

NEBRASKA SOUTH DAKOTA

WISCONSIN

9

8 7

6

5

4

3

2

1

96

95 94

93

92

91

90

89

88

87

86 85

84

83

82

78 80 77

76

75

74

73

72 71

69

68

67

6665

64

63

62

61

60

59

58

57

55 56

54

53

52

51

50

49

48

47

46

45

44 43

42

41

40

39

38 37

36 35 34

33 32

29

28

27

26 25

24

23

22

21

20

19

18

17

16

15

14

13

12

10

11

79

70

81

30

31

96° 95° 94° 93° 92° 91° 90°

44°

43°

42°

41°

Streamflow-gaging station type and map number 

(table 1)

# Calibration location

*# Validation location

*# Input location

Stream segments—Each color represents 

a simulated stream segment

Upper Iowa River Basin

Yellow River Basin

Turkey River Basin

Maquoketa RiverBasin

Wapsipinicon RiverBasin

Iowa River Basin

Skunk River Basin

Des Moines River Basin

Fox River Basin

70

64

93

Base from U.S. Geological Survey digital data, 1: 2,000,000, 1979

Universal Transverse Mercator projection, zone 15

North American Datum of 1983 (NAD 83)

0 40

40

80 MILES

0 80 KILOMETERS

EXPLANATION

Precipitation-Runoff 

Modeling System boundary

Figure 2. Simulated stream segments and U.S. Geological Survey streamflow-gaging stations providing measured data for 

Precipitation-Runoff Modeling System models of nine river basins in eastern Iowa. 
Introduction 5

Table 1. U.S. Geological Survey streamflow-gaging stations used for input, calibrating, and validating the Precipitation-Runoff 

Modeling System models of nine river basins in eastern Iowa.

[USGS, U.S. Geological Survey; latitude and longitude in decimal degrees; mi2, square miles; IA, Iowa; Cr, creek; NE, Northeast; nr, near; MN, Minnesota; DS, 

downstream; MO, Missouri]

Map 

number 

(fig. 2)

USGS 

station 

number

USGS station name Latitude 

(north)

Longitude 

(west)

Drainage 

area 

measured 

at gage 

(mi2

)

Period of record used

Upper Iowa River Basin

1 05387440 Upper Iowa River at Bluffton, IA 43.4069 91.8990 367 10/01/2002–09/30/2012

2 05387500 Upper Iowa River at Decorah, IA 43.3049 91.7955 511 10/01/2002–09/30/2012

3 05388250 Upper Iowa River near Dorchester, IA 43.4211 91.5088 770 10/01/2002–09/30/2012

Yellow River Basin

4 05389000 Yellow River near Ion, IA 43.1119 91.2651 221 10/01/2004–09/30/2012

Turkey River Basin

5 05411600 Turkey River at Spillville, IA 43.2073 91.9503 177 05/01/2010–09/30/2012

6 05411850 Turkey River near Eldorado, IA 43.0542 91.8091 641 10/01/2002–09/30/2012

7 05412020 Turkey River above French Hollow Cr at Elkader, IA 42.8435 91.4013 903 10/01/2002–09/30/2012

8 05412340 Volga River at Fayette, IA 42.8441 91.8182 130 05/01/2010–09/30/2012

9 05412400 Volga River at Littleport, IA 42.7539 91.3690 348 10/01/2002–09/30/2012

10 05412500 Turkey River at Garber, IA 42.7400 91.2618 1,545 10/01/2002–09/30/2012

Maquoketa River Basin

11 05416900 Maquoketa River at Manchester, IA 42.1643 90.7293 275 06/23/2003–09/30/2012

12 05418400 North Fork Maquoketa River near Fulton, IA 42.4700 91.4487 505 10/01/2002–09/30/2012

13 05418500 Maquoketa River near Maquoketa, IA 42.0834 90.6329 1,553 10/01/2002–09/30/2012

Wapsipinicon River Basin

14 05420560 Wapsipinicon River near Elma, IA 43.2416 92.5331 95.2 10/01/1981–09/30/1992

15 05420680 Wapsipinicon River near Tripoli, IA 42.8361 92.2574 346 10/01/2006–09/30/2012

16 05421000 Wapsipinicon River at Independence, IA 42.4636 91.8952 1,048 10/01/2002–09/30/2012

17 05421682 Buffalo Creek South of Prairieburg, IA 42.1958 91.4228 189 04/09/2002–09/30/2012

18 05421740 Wapsipinicon River near Anamosa, IA 42.0833 91.2674 1,575 10/01/2002–09/30/2012

19 05421760 Wapsipinicon River at Oxford Mills, IA 41.9719 90.9600 1,792 04/13/2002–09/30/2012

20 05422000 Wapsipinicon River near De Witt, IA 41.7670 90.5349 2,336 10/01/2002–09/30/2012

Iowa River Basin

21 05449500 Iowa River near Rowan, IA 42.7599 93.6218 429 10/01/2002–09/30/2012

22 05451210 South Fork Iowa River NE of New Providence, IA 42.3151 93.1521 224 10/01/2002–09/30/2012

23 05451500 Iowa River at Marshalltown, IA 42.0658 92.9077 1,532 10/01/2002–09/30/2012

24 05451700 Timber Creek near Marshalltown, IA 42.0089 92.8524 118 10/01/2002–09/30/2012

25 05451900 Richland Creek near Haven, IA 41.8994 92.4744 56.1 10/01/2002–09/30/2012

26 05452000 Salt Creek near Elberon, IA 41.9642 92.3132 201 10/01/2002–09/30/2012

27 05452200 Walnut Creek near Hartwick, IA 41.8350 92.3863 70.9 10/01/2002–09/30/2012

28 05453000 Big Bear Creek at Ladora, IA 41.7494 92.1821 189 10/01/2002–09/30/2012

29 05453100 Iowa River at Marengo, IA 41.8127 92.0648 2,794 10/01/2002–09/30/2012

30 05453520 Iowa River below Coralville Dam nr Coralville, IA1 41.7153 91.5302 3,115 10/01/2002–09/30/2012

31 05454000 Rapid Creek near Iowa City, IA 41.7000 91.4877 25.3 10/01/2002–09/30/2012

32 05454090 Muddy Creek at Coralville, IA 41.7000 91.5628 8.7 10/01/2002–09/30/2012
6 Simulation of Daily Streamflow for Nine River Basins in Eastern Iowa Using the Precipitation-Runoff Modeling System 

Table 1. U.S. Geological Survey streamflow-gaging stations used for input, calibrating, and validating the Precipitation-Runoff 

Modeling System models of nine river basins in eastern Iowa.—Continued

[USGS, U.S. Geological Survey; latitude and longitude in decimal degrees; mi2, square miles; IA, Iowa; Cr, creek; NE, Northeast; nr, near; MN, Minnesota; DS, 

downstream; MO, Missouri]

Map 

number 

(fig. 2)

USGS 

station 

number

USGS station name Latitude 

(north)

Longitude 

(west)

Drainage 

area 

measured 

at gage 

(mi2

)

Period of record used

Iowa River Basin—Continued

33 05454220 Clear Creek near Oxford, IA 41.7183 91.7402 58.4 10/01/2002–09/30/2012

34 05454300 Clear Creek near Coralville, IA 41.6767 91.5988 98.1 10/01/2002–09/30/2012

35 05454500 Iowa River at Iowa City, IA 41.6567 91.5410 3,271 10/01/2002–09/30/2012

36 05455100 Old Mans Creek near Iowa City, IA 41.6064 91.6157 201 10/01/2002–09/30/2012

37 05455500 English River at Kalona, IA 41.4697 91.7146 574 10/01/2002–09/30/2012

38 05455700 Iowa River near Lone Tree, IA 41.4238 91.4785 4,293 10/01/2002–09/30/2012

39 05457000 Cedar River near Austin, MN 43.6372 92.9746 399 10/01/2002–09/30/2012

40 05457700 Cedar River at Charles City, IA 43.0622 92.6739 1,054 10/01/2002–09/30/2012

41 05458000 Little Cedar River near Ionia, IA 43.0333 92.5035 306 10/01/2002–09/30/2012

42 05458300 Cedar River at Waverly, IA 42.7372 92.4701 1,547 10/01/2002–09/30/2012

43 05458500 Cedar River at Janesville, IA 42.6483 92.4652 1,661 10/01/2002–09/30/2012

44 05458900 West Fork Cedar River at Finchford, IA 42.6294 92.5435 846 10/01/2002–09/30/2012

45 05459500 Winnebago River at Mason City, IA 43.1650 93.1927 526 10/01/2002–09/30/2012

46 05462000 Shell Rock River at Shell Rock, IA 42.7119 92.5830 1,746 10/01/2002–09/30/2012

47 05463000 Beaver Creek at New Hartford, IA 42.5720 92.6183 347 10/01/2002–09/30/2012

48 05463500 Black Hawk Creek at Hudson, IA 42.4078 92.4632 303 10/01/2002–09/30/2012

49 05464000 Cedar River at Waterloo, IA 42.4955 92.3344 5,146 10/01/2002–09/30/2012

50 05464220 Wolf Creek near Dysart, IA 42.2515 92.2989 299 10/01/2002–09/30/2012

51 05464500 Cedar River at Cedar Rapids, IA 41.9719 91.6671 6,510 10/01/2002–09/30/2012

52 05465000 Cedar River near Conesville, IA 41.4092 91.2904 7,787 10/01/2002–09/30/2012

53 05465500 Iowa River at Wapello, IA 41.1781 91.1821 12,500 10/01/2002–09/30/2012

Skunk River Basin

54 05470000 South Skunk River near Ames, IA 42.0665 93.6201 315 10/01/2002–09/30/2012

55 05470500 Squaw Creek at Ames, IA 42.0230 93.6305 204 10/01/2002–09/30/2012

56 05471000 South Skunk River below Squaw Creek near Ames, IA 42.0067 93.5955 556 10/01/2002–09/30/2012

57 05471050 South Skunk River at Colfax, IA 41.6814 93.2466 803 10/01/2002–09/30/2012

58 05471200 Indian Creek near Mingo, IA 41.8053 93.3094 276 10/01/2002–09/30/2012

59 05471500 South Skunk River near Oskaloosa, IA 41.3557 92.6574 1,635 10/01/2002–09/30/2012

60 05472500 North Skunk River near Sigourney, IA 41.3008 92.2046 730 10/01/2002–09/30/2012

61 05473400 Cedar Creek near Oakland Mills, IA 40.9253 91.6742 530 10/01/2002–09/30/2012

62 05473450 Big Creek North of Mount Pleasant, IA 41.0070 91.5516 58 10/01/2002–09/30/2012

63 05474000 Skunk River at Augusta, IA 40.7537 91.2771 4,312 10/01/2002–09/30/2012

Des Moines River Basin

64 05476000 Des Moines River at Jackson, MN 43.6183 94.9850 1,250 10/01/2002–09/30/2012

65 05476750 Des Moines River at Humboldt, IA 42.7194 94.2205 2,256 10/01/2002–09/30/2012

66 05479000 East Fork Des Moines River at Dakota City, IA 42.7236 94.1935 1,308 10/01/2002–09/30/2012

67 05480500 Des Moines River at Fort Dodge, IA 42.5083 94.2036 4,190 10/01/2002–09/30/2012
Introduction 7

Table 1. U.S. Geological Survey streamflow-gaging stations used for input, calibrating, and validating the Precipitation-Runoff 

Modeling System models of nine river basins in eastern Iowa.—Continued

[USGS, U.S. Geological Survey; latitude and longitude in decimal degrees; mi2, square miles; IA, Iowa; Cr, creek; NE, Northeast; nr, near; MN, Minnesota; DS, 

downstream; MO, Missouri]

Map 

number 

(fig. 2)

USGS 

station 

number

USGS station name Latitude 

(north)

Longitude 

(west)

Drainage 

area 

measured 

at gage 

(mi2

)

Period of record used

Des Moines River Basin—Continued

68 05481000 Boone River near Webster City, IA 42.4325 93.8058 844 10/01/2002–09/30/2012

69 05481300 Des Moines River near Stratford, IA 42.2519 93.9969 5,452 10/01/2002–09/30/2012

70 05481650 Des Moines River near Saylorville, IA1 41.6805 93.6683 5,841 10/01/2002–09/30/2012

71 05481950 Beaver Creek near Grimes, IA 41.6883 93.7355 358 10/01/2002–09/30/2012

72 05482000 Des Moines River at 2nd Avenue at Des Moines, IA 41.6125 93.6210 6,245 10/01/2002–09/30/2012

73 05482300 North Raccoon River near Sac City, IA 42.3548 94.9903 700 10/01/2002–09/30/2012

74 05482500 North Raccoon River near Jefferson, IA 41.9880 94.3769 1,619 10/01/2002–09/30/2012

75 05483450 Middle Raccoon River near Bayard, IA 41.7791 94.4929 375 10/01/2002–09/30/2012

76 05483600 Middle Raccoon River at Panora, IA 41.6872 94.3711 440 10/01/2002–09/30/2012

77 05484000 South Raccoon River at Redfield, IA 41.5894 94.1513 994 10/01/2002–09/30/2012

78 05484500 Raccoon River at Van Meter, IA 41.5339 93.9500 3,441 10/01/2002–09/30/2012

79 05484650 Raccoon River at 63rd Street at Des Moines, IA 41.5617 93.7036 3,529 10/01/2002–09/30/2012

80 05484800 Walnut Creek at Des Moines, IA 41.5872 93.7033 78.4 10/01/2002–09/30/2012

81 05484900 Raccoon River at Fleur Drive at Des Moines, IA 41.5817 93.6430 3,625 10/01/2002–09/30/2012

82 05485500 Des Moines River below Raccoon River at Des Moines, 

IA

41.5778 93.6055 9,879 10/01/2002–09/30/2012

83 05485605 Fourmile Creek near Ankeny, IA DS1 41.7174 93.5701 62.0 10/01/2003–09/30/2012

84 05485640 Fourmile Creek at Des Moines, IA 41.6139 93.5455 92.7 10/01/2002–09/30/2012

85 05486000 North River near Norwalk, IA 41.4579 93.6550 349 10/01/2002–09/30/2012

86 05486490 Middle River near Indianola, IA 41.4242 93.5874 489.4 10/01/2002–09/30/2012

87 05487470 South River near Ackworth, IA 41.3372 93.4863 460 10/01/2002–09/30/2012

88 05487980 White Breast Creek near Dallas, IA 41.2466 93.2902 333 10/01/2002–09/30/2012

89 05488110 Des Moines River near Pella, IA1 41.3606 92.9733 12,330 10/01/2002–09/30/2012

90 05488200 English Creek near Knoxville, IA 41.3006 93.0455 90.1 10/01/2002–09/30/2012

91 05488500 Des Moines River near Tracy, IA 41.2814 92.8615 12,479 10/01/2002–09/30/2012

92 05489000 Cedar Creek near Bussey, IA 41.2190 92.9085 374 10/01/2002–09/30/2012

93 05489500 Des Moines River at Ottumwa, IA 41.0108 92.4113 13,374 10/01/2002–09/30/2012

94 05490500 Des Moines River at Keosauqua, IA 40.7278 91.9596 14,038 10/01/2002–09/30/2012

Fox River Basin

95 05494300 Fox River at Bloomfield, IA 40.7695 92.4188 87.7 10/01/2002–09/30/2012

96 05495000 Fox River at Wayland, MO 40.3924 91.5979 400 10/01/2002–09/30/2012

1

Sites used for historical streamflows.
8 Simulation of Daily Streamflow for Nine River Basins in Eastern Iowa Using the Precipitation-Runoff Modeling System 

The Skunk River Basin drains about 4,355 mi2 southeast 

into the Mississippi River and extends from Hamilton County, 

central Iowa, to Des Moines and Lee Counties, southeast 

Iowa (figs. 1 and 2). Most of the Skunk River Basin is in the 

Southern Iowa Drift Plain, but the most northern part is within 

the Des Moines Lobe (fig. 1). The largest metropolitan areas in 

the Skunk River Basin are Ames and Newton, Iowa. A total of 

10 USGS streamflow-gaging stations in the Skunk River Basin 

were used in this study (table 1; fig. 2).

The Des Moines River Basin drains about 14,470 mi2

and extends from its headwaters in southwest Minnesota to 

its outlet near Keokuk, southeast Iowa (fig. 1). The Raccoon 

River drains about 3,625 mi2 and is the largest tributary to the 

Des Moines River. The Des Moines River Basin lies within 

the Des Moines Lobe in the northern part, and the Southern 

Iowa Drift Plain in the remainder of the basin (fig. 1). The 

Des Moines metropolitan area, Fort Dodge, and Ottumwa, 

Iowa, are the largest urban centers within the Des Moines 

River Basin. A total of 31 USGS streamflow-gaging stations in 

the Des Moines River Basin were used in this study (table 1; 

fig. 2).

The Fox River Basin drains about 405 mi2 of southeast 

Iowa and northeast Missouri to the Mississippi River. The Fox 

River Basin lies within the Southern Iowa Drift Plain (fig. 1). 

The Fox River Basin is mainly agricultural land with little 

urban development. Two USGS streamflow-gaging stations in 

the Fox River Basin were used in this study (table 1; fig. 2).

Model Development

The PRMS is a deterministic, distributed-parameter, 

physical-process-based modeling system developed to evaluate the response of streamflow and general basin hydrology 

to various combinations of climate and land use (Markstrom 

and others, 2015). The PRMS simulates the hydrologic system 

with known physical laws and empirical relations derived 

from basin characteristics (Markstrom and others, 2008). The 

PRMS is designed to account for spatially distributed parameters and basin characteristics. A schematic diagram of how 

basin and climate inputs are simulated in a typical PRMS 

model is shown in figure 3. 

In PRMS, a basin is divided into a series of contiguous 

spatial units called hydrologic response units (HRUs) based 

on hydrologic and physical characteristics such as land surface 

altitude, slope, aspect, plant type and cover, land use, soil 

morphology, geology, drainage boundaries, distribution of 

precipitation, temperature, solar radiation, and flow direction 

(Markstrom and others, 2008). The HRUs receive and produce 

streamflow to and from each other, and to the drainage network consisting of stream segments (Goode and others, 2010). 

Individual HRUs are considered homogenous with respect to 

hydrologic and physical characteristics, and storage components are instantaneously and fully mixed. Energy and water 

balance are computed by PRMS daily for each HRU (Markstrom and others, 2008).

The PRMS models of nine river basins in eastern Iowa 

were constructed in several steps, which included the compilation of necessary datasets, the delineation of HRU boundaries 

to accommodate the stream network and provide streamflows 

at specific locations for calibration and validation, and the 

parameterization of model HRUs and stream segments. This 

section describes the procedures used to prepare input datasets, basin discretization, and parameterization for the PRMS 

models of nine river basins in eastern Iowa.

Delineation and Parameterization of Spatial 

Features 

For this study, a geospatial database was created for use 

within a geographic information system (GIS) to support 

model discretization, characterize the physical features of the 

basins, and estimate PRMS model parameters. The geospatial 

database consisted of the National Land Cover Database, Percent Impervious, U.S. Forest types, U.S. Forest Density, State 

Soil Geographic Database (STATSGO) general soil maps, 

and a digital elevation model (DEM) derived from the USGS 

National Elevation Dataset (NED) (U.S. Geological Survey, 

2007; Homer and others, 2007; U.S. Department of Agriculture, 1994).

The GIS Weasel (Viger and Leavesley, 2007) was used to 

delineate, characterize the physical features of, and estimate 

initial parameter values for input into PRMS models of nine 

river basins in eastern Iowa. The DEMs were processed by 

the GIS Weasel, which created raster datasets of flow direction and flow accumulation. A drainage network was extracted 

from this surface by finding all points at which the flow accumulation is equal to or greater than a user-specified threshold 

(Viger and Leavesley, 2007). Each drainage network was 

segmented at stream tributaries from headwater to the confluence with the Mississippi River. An interactive process in the 

GIS Weasel was used to discretize the HRUs based on the 

drainage network dataset and location of USGS streamflowgaging stations (Viger and Leavesley, 2007). Two-plane HRUs 

are developed to separate contributing areas from left and 

right banks of each stream segment. The Upper Iowa River 

Basin model discretization consists of 66 stream segments and 

132 HRUs; the Yellow River Basin model discretization consists of 17 stream segments and 34 HRUs; the Turkey River 

Basin model discretization consists of 91 stream segments and 

186 HRUs; the Maquoketa River Basin model discretization 

consists of 98 stream segments and 195 HRUs; the Wapsipinicon River Basin model discretization consists of 133 stream 

segments and 265 HRUs; the Iowa River Basin model discretization consists of 1,174 stream segments and 2,340 HRUs; the 

Skunk River Basin model discretization consists of 275 stream 

segments and 550 HRUs; the Des Moines River Basin 

model discretization consists of 1,308 stream segments and 
Model Development 9

Modified from Markstrom and others, 2008

Solar

radiation

Precipitation

Evaporation

Evaporation

Evaporation

and

transpiration

Sublimation Air temperature

Plant canopy

interception

Rain Throughfall Rain

Transpiration

Snowpack

Snowmelt

Surface runoff

to stream or lake

Soil-zone reservoir Impervious-zone reservoir

Lower zone

Recharge zone

Groundwater

recharge

Groundwater

reservoir

Groundwater recharge

Groundwater

sink

Groundwater discharge to stream or lake

Subsurface recharge

Subsurface reservoir Interflow (or subsurface flow) 

to stream or lake

Figure 3. Schematic diagram of a basin and its meteorological inputs (precipitation, air temperature, and solar radiation)

simulated by the Precipitation-Runoff Modeling System.
10 Simulation of Daily Streamflow for Nine River Basins in Eastern Iowa Using the Precipitation-Runoff Modeling System 

2,627 HRUs; and the Fox River Basin model discretization 

consists of 20 stream segments and 40 HRUs (figs. 2 and 4).

Model Input and Measured Data

The PRMS can use many meteorological inputs. Precipitation, minimum temperature, and maximum temperature were 

used in the PRMS models of nine river basins in eastern Iowa 

as the main climatic drivers. In addition to meteorological 

inputs, PRMS also can use streamflow-gaging station data in 

place of simulated streamflow. This is especilly useful where 

flows are heavily affected by upstream regulation. The Iowa 

River and Des Moines River Basin models used streamflowgaging station data as input at USGS streamflow-gaging 

stations 05453520, 05481650, and 05488110 to accurately 

account for outflows from upstream reservoirs during simulations (table 1; fig. 2).

 The USGS streamflow-gaging station data and meteorological datasets for precipitation and temperature were 

prepared using the USGS Downsizer program (Ward-Garrison 

and others, 2009). The Downsizer program is a computer 

application that selects, downloads, verifies, and formats station-based time-series data for PRMS and other environmental 

modeling programs. The quality-control dialog in Downsizer 

was used to select National Oceanic and Atmospheric Administration’s National Weather Service Cooperative Observer 

Program meteorological stations that had data from January 1, 

1980, through September 30, 2012 (National Oceanic and 

Atmospheric Administration, 2014). Meteorological stations 

that had large amounts of missing or bad data values were 

removed from the PRMS input data list, and stations with 

period of record from October 1, 2002, through September 

30, 2012 were retained. The Downsizer software program also 

was used to retrieve USGS streamflow-gaging station daily 

mean streamflow observations at gaged sites in the model 

areas from October 1, 1980, through September 30, 2012. 

Gaged sites were selected based on being in current operation, 

having a minimum period of record of 5 years, and having a 

period of record from October 1, 2002, through September 30, 

2012, with a few exceptions (table 1). The 96 USGS streamflow-gaging stations and 155 meteorological stations included 

in the PRMS model data files of nine river basins in eastern 

Iowa are listed in tables 1–2 and shown in figures 2 and 4. 

Model Calibration, Validation, and Evaluation

Calibration and validation periods used in each basin 

mostly were October 1, 2002, through September 30, 2012. 

The calibration or validation period differed depending on the 

period of record available for daily mean streamflow measurements at U.S. Geological Survey streamflow-gaging stations 

(table 1). 

The PRMS model was calibrated using the Luca computer program (Hay and Umemoto, 2006). Luca is a graphical user interface that provides a simple, systematic way of 

implementing a multiple-objective, stepwise calibration of 

the PRMS model parameters. Luca uses the Shuffled Complex Evolution (SCE) (Duan and others, 1993) global search 

algorithm to calibrate model parameters. Luca has been used 

by researchers to calibrate many PRMS models (Hay and 

Umemoto 2006; Dudley, 2008; Goode and others, 2010; 

Christiansen, 2012; LaFontaine and others, 2013; Haj and others, 2014). 

In this study, Luca was used to complete a multipleobjective, stepwise calibration of the PRMS models of nine 

river basins in eastern Iowa. A total of 79 USGS streamflowgaging stations throughout the nine river basins in eastern 

Iowa were used for calibration with emphasis on matching 

model simulated daily streamflow with measured daily streamflow (fig. 2; table 3). The Luca calibration includes three 

objective functions—low, high, and mean flows—in an effort 

to accurately represent all flow regimes. A basin-wide, sixstep calibration of climate and streamflow related parameters 

(table 4) was initially completed, and additional calibration 

of subbasin streamflow parameters (table 4) was completed at 

selected gaged sites (table 3) to increase the parameter resolution and accuracy. Of the remaining 17 gaged sites (tables 1 

and 3), data from 3 were used for input to account for outflows 

from reservoirs (as discussed in “Model Input and Measured 

Data”), and data from 14 were used for model validation 

to demonstrate potential accuracy of model estimated daily 

streamflows at ungaged sites. 

Statistical tests were used to evaluate how well each 

PRMS model of the nine river basins in eastern Iowa estimated daily streamflow. The Nash Sutcliffe efficiency (NSE), 

coefficient of determination (R2), percent bias (PBIAS), and 

root mean square error-observation standard deviation ratio 

(RSR) statistics (Moriasi and others, 2007; Singh and others, 

2004; Nash and Sutcliffe, 1970) were used to evaluate model 

performance. The NSE is a normalized statistic that provides 

a measure of how well simulated values match measured 

datasets. The NSE values range from -∞ to 1. Values of 0 or 

less indicate that the mean measured streamflow is a better 

predictor than simulated streamflows. A value of 0.0 indicates 

the simulated streamflow is as good as using the average value 

of all the measured data, and a value of 1 indicates a perfect fit 

between measured and simulated values. Moriasi and others 

(2007) suggest that a monthly NSE of greater than 0.50 is satisfactory in basin models such as PRMS. Although daily values may be lower than 0.50 and still hold a satisfactory rating, 

an NSE value of greater than 0.50 is considered satisfactory. 

The R2 evaluates how accurately the model tracks the 

variability in the measured data that is explained by the simulated data. The R2 can reveal the strength of the linear relationship between the predicted and the measured values. It can 

range from 0 and 1, and the closer the value is to 1 the better 

the linear correlation between simulated and measured values 

(Kalin and Hantush, 2006). Values above 0.5 are considered to 

be satisfactory (Gassman and others, 2007). 

The PBIAS measures the average tendency of the 

simulated data to be larger or smaller than their observed 
Model Development 11

IOWA

KANSAS

ILLINOIS

MISSOURI

MINNESOTA

NEBRASKA SOUTH DAKOTA

WISCONSIN

9 8

7

6

5

4

3

2

1

99

98

97

96

95

94

93

92

91

90

89

88

87

86

85

84

83

82

81

80

79

78

77

76

75

74

73

72

71

70

69

68

67

66 65

64

63

62

61

60

59

58

57

56

55

54

53

52

51

50

49

48

47

46

45

44

43

42 41

40

39

38

37

36

35

34

33

32

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

155

154

153

152

151

150

149

148

147

146 145 144

143

142

141

140

139

138

137

136

135

134 133

132

131 130

129

128

127

126

125

124

123

122

121

120

119

118

117

116

115

114

113

112

111

110

109 108

107

106

105

104

103

102

101

100

96° 95° 94° 93° 92° 91° 90°

44°

43°

42°

41°

40°

EXPLANATION

Meteorological stations and 

map number (table 3)

Precipitation

Temperature

Precipitation and temperature

Upper Iowa River Basin 

Yellow River Basin

Turkey River Basin

Maquoketa River Basin

Wapsipinicon River Basin

Iowa River Basin

Skunk River Basin

Des Moines River Basin

Fox River Basin

21

2

14

Base from U.S. Geological Survey digital data, 1: 2,000,000, 1979

Universal Transverse Mercator projection, zone 15

North American Datum of 1983 (NAD 83)

0 40

40

80 MILES

0 80 KILOMETERS

Hydrologic response units used in the 

Precipitation-Runoff Modeling System

Figure 4. National Oceanic and Atmospheric Administration’s National Weather Service Cooperative Observer Program 

meteorological stations and hydrologic response units used in the Precipitation-Runoff Modeling System models or nine river basins in 

eastern Iowa.
12 Simulation of Daily Streamflow for Nine River Basins in Eastern Iowa Using the Precipitation-Runoff Modeling System 

Table 2. National Oceanic and Atmospheric Administration’s National Weather Service Cooperative Observer Program meteorological 

stations used in the Precipitation-Runoff Modeling System models of nine river basins in eastern Iowa.

[Latitude and longitude in decimal degrees; IL, Illinois; NNE, north, northeast; IA, Iowa; W, west; WSW, west, southwest; SE, southeast; WNW, west, northwest; S, south; E, east; NE, northeast; Wsfo, weather service forecast office; N, north; ft, fort; Mt, Mount; NNW, north, northwest; SW, southwest; NW, northwest; SSW, south, southwest; MN, Minnesota; MO, Missouri; WI, Wisconsin]

Map 

number 

(fig. 4)

Station 

number Meteorological station name Latitude (north)

Longitude 

(west) Elevation Period of record used

1 110598 Bentley, IL 40.3444 91.1125 650.00 10/01/2001–09/30/2012

2 112745 Elizabeth, IL 42.3161 90.2269 675.00 10/01/2001–09/30/2012

3 113290 Fulton Dam, IL 41.8978 90.1544 592.00 10/01/2001–09/30/2012

4 113312 Galena, IL 42.3994 90.3861 753.00 10/01/2001–09/30/2012

5 114355 Illinois City Dam 16, IL 41.4256 91.0094 550.00 10/01/2001–09/30/2012

6 114823 La Harpe, IL 40.5839 90.9686 690.00 10/01/2001–09/30/2012

7 116080 New Boston Dam 17, IL 41.1925 91.0578 548.00 10/01/2001–09/30/2012

8 117072 Quincy Regional Airport, IL 39.9369 91.1919 769.00 10/01/2001–09/30/2012

9 117077 Quincy Dam 21, IL 39.9058 91.4281 483.00 10/01/2001–09/30/2012

10 117388 Rock Island Lock and Dam 15, IL 41.5181 90.5647 568.00 10/01/2001–09/30/2012

11 130112 Albia 3 NNE, IA 41.0656 92.7867 880.00 10/01/2001–09/30/2012

12 130133 Algona 3 W, IA 43.0683 94.3053 1,239.00 10/01/2001–09/30/2012

13 130157 Allison, IA 42.7536 92.8022 1,048.00 10/01/2001–09/30/2012

14 130193 Amana, IA 41.8083 91.8750 730.00 10/01/2001–09/30/2012

15 130197 Ames Municipal Airport, IA 41.9906 93.6189 955.00 10/01/2001–09/30/2012

16 130200 Ames 8 WSW, IA 42.0208 93.7742 1,099.00 10/01/2001–09/30/2012

17 130203 Ames 5 SE, IA 41.9519 93.5656 870.00 10/01/2001–09/30/2012

18 130213 Anamosa 1 WNW, IA 42.1117 91.2933 805.00 10/01/2001–09/30/2012

19 130241 Ankeny, IA 41.7183 93.5742 940.00 10/01/2001–09/30/2012

20 130385 Audubon, IA 41.7069 94.9222 1,280.00 10/01/2001–09/30/2012

21 130600 Belle Plaine, IA 41.8814 92.2764 810.00 10/01/2001–09/30/2012

22 130608 Bellevue Lock and Dam 12, IA 42.2611 90.4231 603.00 10/01/2001–09/30/2012

23 130753 Bloomfield 1 WNW, IA 40.7597 92.4394 812.00 10/01/2001–09/30/2012

24 130807 Boone, IA 42.0417 93.8906 1,051.00 10/01/2001–09/30/2012

25 130933 Brooklyn, IA 41.7394 92.4400 910.00 10/01/2001–09/30/2012

26 130999 Buckeye, IA 42.4172 93.3775 1,150.00 10/01/2001–09/30/2012

27 131060 Burlington 2 S, IA 40.7747 91.1164 690.00 10/01/2001–09/30/2012

28 131233 Carroll, IA 42.0650 94.8500 1,240.00 10/01/2001–09/30/2012

29 131257 Cascade, IA 42.2989 90.9983 870.00 10/01/2001–09/30/2012

30 131300 Cedar Falls, IA 42.5378 92.4431 763.00 10/01/2001–09/30/2012

31 131314 Cedar Rapids Municipal Airport, IA 41.8833 91.7167 868.00 10/01/2001–09/30/2012

32 131319 Cedar Rapids 1, IA 42.0500 91.5881 810.00 10/01/2001–09/30/2012

33 131394 Chariton 1 E, IA 41.0164 93.2792 940.00 10/01/2001–09/30/2012

34 131402 Charles City, IA 43.0603 92.6717 993.00 10/01/2001–09/30/2012

35 131610 Clermont, IA 42.9975 91.6583 840.00 10/01/2001–09/30/2012

36 131635 Clinton 1, IA 41.7947 90.2639 585.00 10/01/2001–09/30/2012

37 131704 Clutier, IA 42.0800 92.4050 900.00 10/01/2001–09/30/2012

38 131954 Cresco 1 NE, IA 43.3894 92.0939 1,255.00 10/01/2001–09/30/2012

39 132110 Decorah, IA 43.3042 91.7953 860.00 10/01/2001–09/30/2012
Model Development 13

Table 2. National Oceanic and Atmospheric Administration’s National Weather Service Cooperative Observer Program 

meteorological stations used in the Precipitation-Runoff Modeling System models of nine river basins in eastern Iowa.—Continued

[Latitude and longitude in decimal degrees; IL, Illinois; NNE, north, northeast; IA, Iowa; W, west; WSW, west, southwest; SE, southeast; WNW, west, 

northwest; S, south; E, east; NE, northeast; Wsfo, weather service forecast office; N, north; ft, fort; Mt, Mount; NNW, north, northwest; SW, southwest; NW, 

northwest; SSW, south, southwest; MN, Minnesota; MO, Missouri; WI, Wisconsin]

Map 

number 

(fig. 4)

Station 

number Meteorological station name Latitude (north)

Longitude 

(west) Elevation Period of record used

40 132112 Decorah 2 S, IA 43.2833 91.7833 879.00 10/01/2001–09/30/2012

41 132203 Des Moines International Airport, IA 41.5339 93.6531 957.00 10/01/2001–09/30/2012

42 132205 Des Moines 17 E, IA 41.5561 93.2856 921.00 10/01/2001–09/30/2012

43 132209 Des Moines Wsfo Johnston, IA 41.7367 93.7236 959.00 10/01/2001–09/30/2012

44 132235 De Witt, IA 41.8108 90.5406 685.00 10/01/2001–09/30/2012

45 132299 Donnellson, IA 40.6458 91.5639 705.00 10/01/2001–09/30/2012

46 132311 Dorchester, IA 43.4706 91.5108 758.00 10/01/2001–09/30/2012

47 132364 Dubuque Lock and Dam 11, IA 42.5400 90.6461 620.00 10/01/2001–09/30/2012

48 132367 Dubuque Regional Airport, IA 42.3978 90.7036 1,056.00 10/01/2001–09/30/2012

49 132573 Eldora, IA 42.3619 93.0989 1,144.00 10/01/2001–09/30/2012

50 132603 Elkader, IA 42.7753 91.4536 788.00 10/01/2001–09/30/2012

51 132638 Elma, IA 43.2419 92.4433 1,172.00 10/01/2001–09/30/2012

52 132724 Estherville 2 N, IA 43.4036 94.7472 1,320.00 10/01/2001–09/30/2012

53 132725 Estherville Municipal Airport, IA 43.4011 94.7472 1,317.00 10/01/2001–09/30/2012

54 132789 Fairfield, IA 41.0211 91.9553 740.00 10/01/2001–09/30/2012

55 132864 Fayette, IA 42.8503 91.8158 1,130.00 10/01/2001–09/30/2012

56 132977 Forest City 2 NNE, IA 43.2844 93.6306 1,300.00 10/01/2001–09/30/2012

57 132999 Ft Dodge 5 NNW, IA 42.5836 94.2006 1,140.00 10/01/2001–09/30/2012

58 133007 Ft Madison, IA 40.6222 91.3339 530.00 10/01/2001–09/30/2012

59 133120 Garwin, IA 42.0900 92.6756 912.00 10/01/2001–09/30/2012

60 133239 Gilman, IA 41.8781 92.7786 1,040.00 10/01/2001–09/30/2012

61 133438 Greenfield, IA 41.2981 94.4561 1,340.00 10/01/2001–09/30/2012

62 133473 Grinnell 3 SW, IA 41.7203 92.7489 905.00 10/01/2001–09/30/2012

63 133487 Grundy Center, IA 42.3647 92.7594 1,045.00 10/01/2001–09/30/2012

64 133509 Guthrie Center, IA 41.6686 94.4972 1,075.00 10/01/2001–09/30/2012

65 133517 Guttenberg Lock and Dam 10, IA 42.7858 91.0958 618.00 10/01/2001–09/30/2012

66 133584 Hampton, IA 42.7561 93.2011 1,230.00 10/01/2001–09/30/2012

67 133960 Hubbard, IA 42.3008 93.3008 1,089.00 10/01/2001–09/30/2012

68 134063 Indianola, IA 41.3656 93.6481 942.00 10/01/2001–09/30/2012

69 134094 Ionia 2 W, IA 43.0336 92.5017 1,019.00 10/01/2001–09/30/2012

70 134101 Iowa City, IA 41.6092 91.5050 640.00 10/01/2001–09/30/2012

71 134106 Iowa City Municipal Airport, IA 41.6328 91.5431 650.00 10/01/2001–09/30/2012

72 134142 Iowa Falls, IA 42.5189 93.2536 1,130.00 10/01/2001–09/30/2012

73 134228 Jefferson, IA 42.0347 94.4114 1,055.00 10/01/2001–09/30/2012

74 134244 Jewell, IA 42.3008 93.6389 1,060.00 10/01/2001–09/30/2012

75 134308 Kanawha, IA 42.9311 93.7933 1,185.00 10/01/2001–09/30/2012

76 134381 Keokuk Lock and Dam 19, IA 40.3967 91.3750 527.00 10/01/2001–09/30/2012

77 134389 Keosauqua, IA 40.7275 91.9683 592.00 10/01/2001–09/30/2012

78 134502 Knoxville, IA 41.3247 93.1008 915.00 10/01/2001–09/30/2012
14 Simulation of Daily Streamflow for Nine River Basins in Eastern Iowa Using the Precipitation-Runoff Modeling System 

Table 2. National Oceanic and Atmospheric Administration’s National Weather Service Cooperative Observer Program 

meteorological stations used in the Precipitation-Runoff Modeling System models of nine river basins in eastern Iowa.—Continued

[Latitude and longitude in decimal degrees; IL, Illinois; NNE, north, northeast; IA, Iowa; W, west; WSW, west, southwest; SE, southeast; WNW, west, 

northwest; S, south; E, east; NE, northeast; Wsfo, weather service forecast office; N, north; ft, fort; Mt, Mount; NNW, north, northwest; SW, southwest; NW, 

northwest; SSW, south, southwest; MN, Minnesota; MO, Missouri; WI, Wisconsin]

Map 

number 

(fig. 4)

Station 

number Meteorological station name Latitude (north)

Longitude 

(west) Elevation Period of record used

79 134557 Lake Mills, IA 43.4178 93.5347 1,260.00 10/01/2001–09/30/2012

80 134705 Le Claire Lock and Dam 14, IA 41.5747 90.4006 577.00 10/01/2001–09/30/2012

81 134963 Lowden, IA 41.8564 90.9300 715.00 10/01/2001–09/30/2012

82 135086 Manchester 2, IA 42.4733 91.4517 990.00 10/01/2001–09/30/2012

83 135131 Maquoketa, IA 42.0494 90.7489 762.00 10/01/2001–09/30/2012

84 135198 Marshalltown, IA 42.0647 92.9244 870.00 10/01/2001–09/30/2012

85 135199 Marshalltown Municipal Airport, IA 42.1106 92.9161 974.00 10/01/2001–09/30/2012

86 135230 Mason City, IA 43.1631 93.1953 1,105.00 10/01/2001–09/30/2012

87 135232 Mason City 1, IA 43.1533 93.1981 1,097.00 10/01/2001–09/30/2012

88 135235 Mason City Municipal Airport, IA 43.1544 93.3269 1,225.00 10/01/2001–09/30/2012

89 135493 Milford 4 NW, IA 43.3828 95.1842 1,402.00 10/01/2001–09/30/2012

90 135622 Monmouth 4 SW, IA 42.0500 90.9167 869.00 10/01/2001–09/30/2012

91 135650 Montezuma 1 W, IA 41.5836 92.5497 965.00 10/01/2001–09/30/2012

92 135796 Mt Pleasant 1 SSW, IA 40.9486 91.5647 730.00 10/01/2001–09/30/2012

93 135837 Muscatine, IA 41.4075 91.0728 549.00 10/01/2001–09/30/2012

94 135844 Muscatine 2 N, IA 41.4714 91.0464 680.00 10/01/2001–09/30/2012

95 135952 New Hampton, IA 43.0453 92.3122 1,148.00 10/01/2001–09/30/2012

96 135992 Newton, IA 41.7117 93.0297 960.00 10/01/2001–09/30/2012

97 136103 Northwood, IA 43.4386 93.2253 1,190.00 10/01/2001–09/30/2012

98 136200 Oelwein 2 S, IA 42.6467 91.9131 1,010.00 10/01/2001–09/30/2012

99 136305 Osage, IA 43.2794 92.8106 1,170.00 10/01/2001–09/30/2012

100 136316 Osceola, IA 41.0194 93.7503 1,028.00 10/01/2001–09/30/2012

101 136327 Oskaloosa, IA 41.3214 92.6467 830.00 10/01/2001–09/30/2012

102 136389 Ottumwa Industrial Airport, IA 41.1078 92.4467 842.00 10/01/2001–09/30/2012

103 136527 Pella 1 S, IA 41.3761 92.9203 780.00 10/01/2001–09/30/2012

104 136566 Perry, IA 41.8394 94.1106 965.00 10/01/2001–09/30/2012

105 136719 Pocahontas, IA 42.7292 94.6614 1,212.00 10/01/2001–09/30/2012

106 136755 Popejoy 1S, IA 42.5864 93.4364 1,175.00 10/01/2001–09/30/2012

107 136766 Postville, IA 43.0900 91.5581 1,165.00 10/01/2001–09/30/2012

108 137161 Rockwell City, IA 42.3969 94.6292 1,195.00 10/01/2001–09/30/2012

109 137312 Sac City, IA 42.4194 94.9761 1,210.00 10/01/2001–09/30/2012

110 137678 Sigourney, IA 41.3328 92.1975 800.00 10/01/2001–09/30/2012

111 137726 Sioux Rapids 4 E, IA 42.8931 95.0653 1,420.00 10/01/2001–09/30/2012

112 137859 Spirit Lake, IA 43.4231 95.1394 1,420.00 10/01/2001–09/30/2012

113 137932 Steamboat Rock, IA 42.4069 93.0697 980.00 10/01/2001–09/30/2012

114 137979 Storm Lake 2 E, IA 42.6347 95.1694 1,425.00 10/01/2001–09/30/2012

115 138026 Swea City, IA 43.4022 94.3831 1,239.00 10/01/2001–09/30/2012

116 138062 Swisher, IA 41.8497 91.6764 790.00 10/01/2001–09/30/2012

117 138296 Toledo 3 N, IA 42.0356 92.5806 949.00 10/01/2001–09/30/2012
Model Development 15

Table 2. National Oceanic and Atmospheric Administration’s National Weather Service Cooperative Observer Program 

meteorological stations used in the Precipitation-Runoff Modeling System models of nine river basins in eastern Iowa.—Continued

[Latitude and longitude in decimal degrees; IL, Illinois; NNE, north, northeast; IA, Iowa; W, west; WSW, west, southwest; SE, southeast; WNW, west, 

northwest; S, south; E, east; NE, northeast; Wsfo, weather service forecast office; N, north; ft, fort; Mt, Mount; NNW, north, northwest; SW, southwest; NW, 

northwest; SSW, south, southwest; MN, Minnesota; MO, Missouri; WI, Wisconsin]

Map 

number 

(fig. 4)

Station 

number Meteorological station name Latitude (north)

Longitude 

(west) Elevation Period of record used

118 138339 Tripoli, IA 42.8125 92.2575 960.00 10/01/2001–09/30/2012

119 138568 Vinton, IA 42.1703 92.0078 850.00 10/01/2001–09/30/2012

120 138632 Walford 2 SE, IA 41.8625 91.8025 790.00 10/01/2001–09/30/2012

121 138668 Wapello, IA 41.1761 91.1922 590.00 10/01/2001–09/30/2012

122 138688 Washington, IA 41.2825 91.7078 687.00 10/01/2001–09/30/2012

123 138706 Waterloo Municipal Airport, IA 42.5544 92.4011 868.00 10/01/2001–09/30/2012

124 138742 Waucoma 3 SE, IA 43.0533 92.0372 1,045.00 10/01/2001–09/30/2012

125 138755 Waukon, IA 43.2742 91.4711 1,275.00 10/01/2001–09/30/2012

126 138806 Webster City, IA 42.4686 93.7972 1,170.00 10/01/2001–09/30/2012

127 139067 Williamsburg, IA 41.6403 91.9783 810.00 10/01/2001–09/30/2012

128 139132 Winterset 2 NNW, IA 41.3561 94.0128 1,040.00 10/01/2001–09/30/2012

129 139750 Zearing, IA 42.1669 93.3097 1,116.00 10/01/2001–09/30/2012

130 210075 Albert Lea 3 SE, MN 43.6064 93.3019 1,230.00 10/01/2001–09/30/2012

131 210355 Austin Waste Water Treatment 

Facility, MN

43.6542 92.9739 1,199.00 10/01/2001–09/30/2012

132 210981 Bricelyn, MN 43.5439 93.8422 1,170.00 10/01/2001–09/30/2012

133 211198 Caledonia, MN 43.6308 91.5028 1,166.00 10/01/2001–09/30/2012

134 212698 Fairmont, MN 43.6447 94.4656 1,187.00 10/01/2001–09/30/2012

135 213290 Grand Meadow, MN 43.7047 92.5644 1,350.00 10/01/2001–09/30/2012

136 213520 Harmony, MN 43.5458 92.0122 1,350.00 10/01/2001–09/30/2012

137 214453 Lakefield, MN 43.7022 95.1519 1,530.00 10/01/2001–09/30/2012

138 214534 Lake Wilson, MN 43.9981 95.9572 1,650.00 10/01/2001–09/30/2012

139 214563 Lanesboro, MN 43.7203 91.9717 955.00 10/01/2001–09/30/2012

140 216654 Preston, MN 43.6725 92.0747 930.00 10/01/2001–09/30/2012

141 218323 Tracy, MN 44.2394 95.6308 1,403.00 10/01/2001–09/30/2012

142 219033 Windom, MN 43.8575 95.1167 1,375.00 10/01/2001–09/30/2012

143 219170 Worthington 2 NNE, MN 43.6450 95.5803 1,570.00 10/01/2001–09/30/2012

144 231275 Canton Lock and Dam 20, MO 40.1433 91.5158 490.00 10/01/2001–09/30/2012

145 232482 Edina, MO 40.1636 92.1658 808.00 10/01/2001–09/30/2012

146 234544 Kirksville, MO 40.2058 92.5747 970.00 10/01/2001–09/30/2012

147 235492 Memphis, MO 40.4575 92.1822 770.00 10/01/2001–09/30/2012

148 238051 Steffenville, MO 39.9714 91.8872 690.00 10/01/2001–09/30/2012

149 473038 Genoa Dam 8, WI 43.5706 91.2294 639.00 10/01/2001–09/30/2012

150 474546 Lancaster 4 WSW, WI 42.8278 90.7889 1,040.00 10/01/2001–09/30/2012

151 474937 Lynxville Dam 9, WI 43.2117 91.0986 633.00 10/01/2001–09/30/2012

152 476646 Platteville, WI 42.7489 90.4656 990.00 10/01/2001–09/30/2012

153 476827 Prairie Du Chien, WI 43.0514 91.1350 658.00 10/01/2001–09/30/2012

154 478164 Steuben 4 SE, WI 43.1342 90.8372 1,015.00 10/01/2001–09/30/2012

155 478827 Viroqua, WI 43.5594 90.8761 1,255.00 10/01/2001–09/30/2012
16 Simulation of Daily Streamflow for Nine River Basins in Eastern Iowa Using the Precipitation-Runoff Modeling System 

Table 3. Nash-Sutcliffe efficiency, coefficient of determination, percent bias, and root mean square error-observation standard 

deviation ratio statistic values at U.S. Geological Survey streamflow-gaging stations used for calibration or validation periods in the 

Precipitation-Runoff Modeling System models of nine river basins in eastern Iowa.

[Red indicates that statistic value below satisfactory rating level. USGS, U.S. Geological Survey; NSE, Nash-Sutcliffe efficiency; R2, coefficient of determination; PBIAS, percent bias; RSR, root mean square error-observation standard deviation ratio; IA, Iowa; C, calibration location; Cr, Creek; V, validation location; 

NE, Northeast; MN, Minnesota; DS, downstream; MO, Missouri]

Map 

number 

(fig. 2)

USGS 

station 

number

USGS station name Type NSE R2 PBIAS RSR

Upper Iowa River Basin

1 05387440 Upper Iowa River at Bluffton, IA C 0.79 0.79 1.25 0.46

2 05387500 Upper Iowa River at Decorah, IA C 0.84 0.85 5.23 0.40

3 05388250 Upper Iowa River near Dorchester, IA C 0.88 0.88 -2.68 0.35

Yellow River Basin

4 05389000 Yellow River near Ion, IA C 0.68 0.71 -7.74 0.56

Turkey River Basin

5 05411600 Turkey River at Spillville, IA C 0.49 0.52 -5.88 0.71

6 05411850 Turkey River near Eldorado, IA C 0.51 0.51 -9.04 0.70

7 05412020 Turkey River above French Hollow Cr at Elkader, IA C 0.61 0.61 -4.06 0.62

8 05412340 Volga River at Fayette, IA C 0.41 0.46 2.64 0.77

9 05412400 Volga River at Littleport, IA C 0.67 0.68 -14.67 0.57

10 05412500 Turkey River at Garber, IA C 0.66 0.66 -8.42 0.59

Maquoketa River Basin

11 05416900 Maquoketa River at Manchester, IA C 0.50 0.51 23.89 0.71

12 05418400 North Fork Maquoketa River near Fulton, IA C 0.55 0.58 11.15 0.67

13 05418500 Maquoketa River near Maquoketa, IA C 0.65 0.68 16.76 0.59

Wapsipinicon River Basin

14 05420560 Wapsipinicon River near Elma, IA C 0.43 0.44 -17.54 0.75

15 05420680 Wapsipinicon River near Tripoli, IA C 0.66 0.70 -24.15 0.58

16 05421000 Wapsipinicon River at Independence, IA V 0.70 0.72 -12.93 0.55

17 05421682 Buffalo Creek South of Prairieburg, IA C 0.53 0.53 -2.30 0.68

18 05421740 Wapsipinicon River near Anamosa, IA V 0.67 0.71 -4.68 0.58

19 05421760 Wapsipinicon River at Oxford Mills, IA V 0.76 0.78 14.79 0.49

20 05422000 Wapsipinicon River near De Witt, IA C 0.70 0.72 1.47 0.55

Iowa River Basin

21 05449500 Iowa River near Rowan, IA C 0.52 0.58 16.15 0.69

22 05451210 South Fork Iowa River NE of New Providence, IA C 0.62 0.65 30.26 0.61

23 05451500 Iowa River at Marshalltown, IA C 0.65 0.68 23.52 0.59

24 05451700 Timber Creek near Marshalltown, IA C 0.45 0.46 14.66 0.74

25 05451900 Richland Creek near Haven, IA C 0.50 0.52 20.46 0.70

26 05452000 Salt Creek near Elberon, IA C 0.65 0.66 16.53 0.59

27 05452200 Walnut Creek near Hartwick, IA C 0.29 0.47 1.29 0.84

28 05453000 Big Bear Creek at Ladora, IA C 0.54 0.55 17.65 0.68

29 05453100 Iowa River at Marengo, IA C 0.73 0.76 20.90 0.52

31 05454000 Rapid Creek near Iowa City, IA C 0.42 0.48 21.18 0.76

32 05454090 Muddy Creek at Coralville, IA V 0.50 0.43 9.51 0.71

33 05454220 Clear Creek near Oxford, IA C 0.54 0.56 20.03 0.68
Model Development 17

Table 3. Nash-Sutcliffe efficiency, coefficient of determination, percent bias, and root mean square error-observation standard 

deviation ratio statistic values at U.S. Geological Survey streamflow-gaging stations used for calibration or validation periods in the 

Precipitation-Runoff Modeling System models of nine river basins in eastern Iowa.—Continued

[Red indicates that statistic value below satisfactory rating level. USGS, U.S. Geological Survey; NSE, Nash-Sutcliffe efficiency; R2, coefficient of determination; PBIAS, percent bias; RSR, root mean square error-observation standard deviation ratio; IA, Iowa; C, calibration location; Cr, Creek; V, validation location; 

NE, Northeast; MN, Minnesota; DS, downstream; MO, Missouri]

Map 

number 

(fig. 2)

USGS 

station 

number

USGS station name Type NSE R2 PBIAS RSR

Iowa River Basin—Continued

34 05454300 Clear Creek near Coralville, IA C 0.60 0.62 21.99 0.63

35 05454500 Iowa River at Iowa City, IA C 0.99 1.00 1.56 0.08

36 05455100 Old Mans Creek near Iowa City, IA C 0.56 0.58 17.97 0.66

37 05455500 English River at Kalona, IA C 0.52 0.54 22.77 0.69

38 05455700 Iowa River near Lone Tree, IA C 0.92 0.92 5.10 0.28

39 05457000 Cedar River near Austin, MN C 0.39 0.42 14.97 0.78

40 05457700 Cedar River at Charles City, IA C 0.63 0.66 14.52 0.61

41 05458000 Little Cedar River near Ionia, IA C 0.70 0.70 -3.57 0.55

42 05458300 Cedar River at Waverly, IA C 0.73 0.74 11.24 0.52

43 05458500 Cedar River at Janesville, IA C 0.77 0.78 17.50 0.48

44 05458900 West Fork Cedar River at Finchford, IA C 0.64 0.66 18.59 0.60

45 05459500 Winnebago River at Mason City, IA C 0.53 0.60 17.06 0.69

46 05462000 Shell Rock River at Shell Rock, IA C 0.65 0.68 16.34 0.59

47 05463000 Beaver Creek at New Hartford, IA C 0.69 0.73 26.88 0.55

48 05463500 Black Hawk Creek at Hudson, IA C 0.59 0.62 31.82 0.64

49 05464000 Cedar River at Waterloo, IA C 0.79 0.82 21.84 0.46

50 05464220 Wolf Creek near Dysart, IA C 0.56 0.59 30.32 0.66

51 05464500 Cedar River at Cedar Rapids, IA V 0.77 0.79 17.26 0.48

52 05465000 Cedar River near Conesville, IA V 0.67 0.70 17.56 0.58

53 05465500 Iowa River at Wapello, IA V 0.74 0.77 11.53 0.51

Skunk River Basin

54 05470000 South Skunk River near Ames, IA C 0.69 0.69 -6.26 0.56

55 05470500 Squaw Creek at Ames, IA C 0.65 0.66 -6.92 0.59

56 05471000 South Skunk River below Squaw Creek near Ames, IA C 0.72 0.74 -10.67 0.52

57 05471050 South Skunk River at Colfax, IA C 0.57 0.66 -4.22 0.66

58 05471200 Indian Creek near Mingo, IA C 0.69 0.72 -6.51 0.55

59 05471500 South Skunk River near Oskaloosa, IA C 0.50 0.63 0.89 0.70

60 05472500 North Skunk River near Sigourney, IA C 0.68 0.70 -2.61 0.57

61 05473400 Cedar Creek near Oakland Mills, IA C 0.68 0.71 1.03 0.57

62 05473450 Big Creek North of Mount Pleasant, IA C 0.57 0.60 19.07 0.66

63 05474000 Skunk River at Augusta, IA C 0.82 0.82 -3.39 0.42

Des Moines River Basin

64 05476000 Des Moines River at Jackson, MN C 0.50 0.58 -4.81 0.71

65 05476750 Des Moines River at Humboldt, IA C 0.64 0.65 12.93 0.60

66 05479000 East Fork Des Moines River at Dakota City, IA C 0.49 0.63 1.35 0.72

67 05480500 Des Moines River at Fort Dodge, IA C 0.69 0.71 7.93 0.55

68 05481000 Boone River near Webster City, IA C 0.61 0.65 24.13 0.62
18 Simulation of Daily Streamflow for Nine River Basins in Eastern Iowa Using the Precipitation-Runoff Modeling System 

Table 3. Nash-Sutcliffe efficiency, coefficient of determination, percent bias, and root mean square error-observation standard 

deviation ratio statistic values at U.S. Geological Survey streamflow-gaging stations used for calibration or validation periods in the 

Precipitation-Runoff Modeling System models of nine river basins in eastern Iowa.—Continued

[Red indicates that statistic value below satisfactory rating level. USGS, U.S. Geological Survey; NSE, Nash-Sutcliffe efficiency; R2, coefficient of determination; PBIAS, percent bias; RSR, root mean square error-observation standard deviation ratio; IA, Iowa; C, calibration location; Cr, Creek; V, validation location; 

NE, Northeast; MN, Minnesota; DS, downstream; MO, Missouri]

Map 

number 

(fig. 2)

USGS 

station 

number

USGS station name Type NSE R2 PBIAS RSR

Des Moines River Basin—Continued

69 05481300 Des Moines River near Stratford, IA C 0.73 0.74 10.46 0.52

71 05481950 Beaver Creek near Grimes, IA C 0.64 0.70 9.18 0.60

72 05482000 Des Moines River at 2nd Avenue at Des Moines, IA V 0.99 0.99 3.04 0.11

73 05482300 North Raccoon River near Sac City, IA C 0.44 0.48 32.56 0.75

74 05482500 North Raccoon River near Jefferson, IA C 0.65 0.65 9.37 0.59

75 05483450 Middle Raccoon River near Bayard, IA C 0.44 0.45 11.20 0.75

76 05483600 Middle Raccoon River at Panora, IA C 0.48 0.48 6.97 0.72

77 05484000 South Raccoon River at Redfield, IA C 0.57 0.57 4.72 0.66

78 05484500 Raccoon River at Van Meter, IA C 0.69 0.71 3.59 0.56

79 05484650 Raccoon River at 63rd Street at Des Moines, IA V 0.72 0.73 9.64 0.52

80 05484800 Walnut Creek at Des Moines, IA C 0.55 0.56 5.70 0.67

81 05484900 Raccoon River at Fleur Drive at Des Moines, IA V 0.74 0.74 10.04 0.51

82 05485500 Des Moines River below Raccoon River at Des Moines, IA V 0.93 0.93 2.56 0.27

83 05485605 Fourmile Creek near Ankeny, IA DS1 C 0.56 0.56 8.91 0.67

84 05485640 Fourmile Creek at Des Moines, IA C 0.59 0.61 14.97 0.64

85 05486000 North River near Norwalk, IA C 0.60 0.60 -2.25 0.63

86 05486490 Middle River near Indianola, IA C 0.47 0.47 -1.36 0.73

87 05487470 South River near Ackworth, IA C 0.46 0.47 9.80 0.74

88 05487980 White Breast Creek near Dallas, IA C 0.45 0.47 -2.09 0.74

90 05488200 English Creek near Knoxville, IA C 0.54 0.55 -8.39 0.68

91 05488500 Des Moines River near Tracy, IA V 1.00 1.00 1.65 0.06

92 05489000 Cedar Creek near Bussey, IA C 0.49 0.50 12.64 0.71

93 05489500 Des Moines River at Ottumwa, IA V 0.98 0.98 1.64 0.14

94 05490500 Des Moines River at Keosauqua, IA V 0.96 0.97 4.63 0.19

Fox River Basin

95 05494300 Fox River at Bloomfield, IA C 0.25 0.27 -12.09 0.87

96 05495000 Fox River at Wayland, MO C 0.61 0.61 -13.99 0.63
Model Development 19

Table 4. Calibrated parameters and Let Us Calibrate (Luca) calibration steps for the Precipitation-Runoff Modeling System models of 

nine river basins in eastern Iowa.

[PRMS, Precipitation-Runoff Modeling System; ET, evapotranspiration; nmonth, 12 months; one, one basin-wide value; NRMSE; normalized root mean square 

error; nhru, number of hydrologic response units; nssr, number of subsurface reservoirs equal to nhru; HRU, hydrologic response unit; ngw, number of groundwater reservoirs equal to nhru; nseg, number of model segments]

Calibration 

dataset Objective function PRMS parameter Dimensions Range Parameter description

Calibration step 1

Solar radiation 

and potential 

ET

Absolute difference dday_intcp nmonth -60–10 Monthly (January to December) intercept in 

degree-day equation.

1. Mean monthly dday_slope nmonth 0.2–0.9 Monthly (January to December) slope in degreeday equation.

jh_coef nmonth 0.005–0.09 Monthly (January to December) air temperature 

coefficient used in Jensen-Haise potential ET 

calculations.

Calibration step 2

Water balance NRMSE: adjust_rain nmonth 0–2.0 Precipitation adjustment factor for rain days.

1. Annual

2. Monthly mean

3. Mean monthly

adjust_snow nmonth 0–2.0 Precipitation adjustment factor for snow days.

Calibration step 3

Daily flow NRMSE: adjmix_rain nmonth 0.6–1.4 Factor to adjust proportion in mixed rain/snow 

event.

1. Daily

2. Monthly mean

cecn_coef nmonth 0.6–1.4 Convection condensation energy coefficient.

freeh2o_cap one 0.01–0.2 Free-water holding capacity of the snowpack.

potet_sublim one 0.1-0.75 Fraction of potential ET that is sublimated from 

snow surface.

slowcoef_lin1 nhru 0.0001–0.05 Linerar subsurface reservoir routing coefficient.

soil_moist_max1 nssr 2–10 Maximum available water holding capacity of soil 

profile.

soil_rech_max1 nssr 1.5–5 Maximum available water holding capacity of 

recharge zone.

emis_noppt one 0.757–1 Emissivity of air on days without precipitation.

tmax_allrain nmonth 30–40 If HRU maximum temperature exceeds this value, 

precipitation is assumed rain.

tmax_allsnow one 30–40 If HRU maximum temperature is below this 

value, precipitation is assumed snow.

Calibration step 4

Daily flow NRMSE: fastcoef_lin1 nhru 0.0001–0.8 Linear preferential-flow routing coeficient.

1. Daily high

2. Monthly high

pref_flow_den1 nhru 0–.1 Preferential-flow pore density.

sat_threshold1 nhru 1–15 Soil saturation threshold, above field-capacity 

threshold.

smidx_coef1 nhru 0.0001–0.8 Coefficient in nonlinear surface runoff contributing area algorithm.

Calibration step 5

Daily flow NRMSE: gwflow_coef 1 ngw 0.001–0.89 Groundwater routing coefficient.

1. Daily low

2. Monthly low

soil2gw_max1 nhru 0–0.5 Maximum value for lower zone excess to groundwater reservoir.

ssr2gw_rate1 nssr 0.05–0.8 Coefficient to route water from subsurface reservoir to groundwater reservoir.
20 Simulation of Daily Streamflow for Nine River Basins in Eastern Iowa Using the Precipitation-Runoff Modeling System 

counterparts (Gupta and others, 1999). A PBIAS value of 0.0 

indicates ideal performance, whereas positive values indicate 

underestimation bias and negative values indicate overestimation bias (Moriasi and others, 2007). Model performance for 

streamflow is considered “very good” if the PBIAS is between 

0 and plus or minus (+/-) 10 percent, “good” if the PBIAS is 

between +/- 10 and +/- 15 percent, “satisfactory” if the PBIAS 

is between +/-15 and +/- 25 percent, and “unsatisfactory” if 

the PBIAS is +/- 25 percent and greater (Moraisi and others, 

2007).

The RSR was developed to use the standard deviation of 

observations to qualify what is considered a low root mean 

square error for model performance (Singh and others, 2004). 

The RSR incorporates the benefits of error index statistics and 

includes a normalization/scaling factor. The RSR ranges from 

0 (optimal value) to a large positive value (poor fit) (Singh and 

others, 2004). The lower the RSR value, the better the model 

simulation performance. If RSR is between 0 and 0.5 then performance is “very good,” if RSR is between 0.5 and 0.6 then 

performance is “good,” RSR between 0.6 and 0.7 is “satisfactory,” and RSR greater than 0.7 is “unsatisfactory” (Moraisi 

and others, 2007). 

The statistics NSE, R2

, PBIAS, and RSR are defined as:

NSE=1 1

2

1

2 − ( −

( −

















=

=

∑

∑

i

n

obs i sim i

i

n

obs i obs i

Q Q

Q Q

, ,

, ,

)

) , (1)

R2= i

n

obs i obs i sim i sim i

i

n

obs i obs i

QQQ Q

Q Q

=

=

∑

∑

 ( ) − ( ) −  



−

0

2

0

, ,,,

( ) , , ( ) − 

  ∑ = 

2

0

2

][ , , i

n

Q Q sim i sim i

(2)

PBIAS= i

n

obs i sim i

i

n

obs i

Q Q

Q

=

=

∑

∑

( −

(

















1

1

100 , ,

,

)

) * (3)

RSR= RMSE

STDEVobs

= i

n

obs i sim i

i

n

obs i obs i

Q Q

Q Q

=

=

∑

∑

( ) − 



 





( ) − 



 





0

2

0

2

, ,

, ,

(4)

where

Qobs,i is the ith measurement for basin streamflow,

Qsim i, is the ith simulated basin streamflow,

Qobs,i is the mean of the measured basin streamflow,

Qsim i, is the mean of the simulated basin streamflow,

RMSE is the root mean square error,

STDEVobs is the standard deviation of the observations, 

and 

n is the total number of measurements.

The PRMS models of nine river basins in eastern Iowa 

were evaluated at 79 calibration and 14 validation gaged 

sites (fig. 2; table 3). The NSE, R2, PBIAS, and RSR daily 

values for the period used for calibration are listed for each 

of these sites (table 3). Based on statistical results, the nine 

eastern Iowa river basin PRMS models are a good fit for daily 

streamflow estimation at most sites because PBIAS and RSR 

ratings range from very good to good, and NSE and R2 ratings 

are satisfactory (table 3). Some headwater sites show unsatisfactory ratings. Explanation of the statistical results by river 

basin is provided in “Simulation of Daily Streamflow for Nine 

River Basins in Eastern Iowa Using the Precipitation-Runoff 

Modeling System.”

Table 4. Calibrated parameters and Let Us Calibrate (Luca) calibration steps for the Precipitation-Runoff Modeling System models of 

nine river basins in eastern Iowa.—Continued

[PRMS, Precipitation-Runoff Modeling System; ET, evapotranspiration; nmonth, 12 months; one, one basin-wide value; NRMSE; normalized root mean square 

error; nhru, number of hydrologic response units; nssr, number of subsurface reservoirs equal to nhru; HRU, hydrologic response unit; ngw, number of groundwater reservoirs equal to nhru; nseg, number of model segments]

Calibration 

dataset Objective function PRMS parameter Dimensions Range Parameter description

Calibration step 6

Daily flow NRMSE: K_coef 1 nseg 1–24 Muskingum storage coefficient.

1. Daily slowcoef_sq1 nhru 0–1 Nonlinerar subsurface reservoir routing coefficient.

fastcoef_sq1 nhru 0–1 Nonlinear preferential-flow routing coeficient.

1

Parameter calibrated in both basin-wide and subbasin calibration.
Simulation of Daily Streamflow for Nine River Basins in Eastern Iowa Using the Precipitation-Runoff Modeling System 21

Simulation of Daily Streamflow for 

Nine River Basins in Eastern Iowa 

Using the Precipitation-Runoff 

Modeling System 

The estimates of PRMS models of nine river basins in 

eastern Iowa for daily streamflow at USGS streamflow-gaging 

stations varied in accuracy when compared to measured daily 

streamflow data. Models were satisfactory at estimating daily 

streamflow at USGS streamflow-gaging stations based on statistical results; however, at some gaged sites, the models were 

below a satisfactory level. Results from the nine eastern Iowa 

River Basin models are presented below.

The Upper Iowa River Basin PRMS model meets the 

criteria for satisfactory fit or better for streamflow estimation 

at all streamflow-gaging stations (table 3). A comparison of 

simulated and measured streamflow at the streamflow-gaging 

station nearest to the outlet, station 05388250, shows that for 

the calibration period (October 1, 2002, through September, 

30, 2012) model output estimates peak timing and volumes 

well, but either overestimates or underestimates some peak 

flow volumes (fig. 5). 

The Yellow River Basin PRMS model also meets the 

criteria for satisfactory fit or better for streamflow estimation 

at all streamflow-gaging stations (table 3). A comparison of 

simulated and measured streamflow at the streamflow-gaging 

station nearest to the outlet, station 0589000, shows that for 

the calibration period (October 1, 2004, through September, 

30, 2012) model output estimates peak timing and volumes 

well (fig. 5). Peak flow events that happen during the winter 

months (January, February, and March) are underestimated 

possibly because of the effects of frozen ground, which are not 

captured in the version of the model used for this study, the 

underestimation of rainfall in a rain-snow event, or underestimation of snow-melt runoff. The model also underestimates 

the record peak flows during 2007 and 2008. These two exceptions and minor base flow discrepancies could be improved 

upon with more extensive and informed calibration. 

The Turkey River Basin PRMS model meets the criteria 

for satisfactory fit or better for streamflow estimation in all 

streamflow-gaging stations except at stations 05411600 and 

05412340 (table 3). A comparison of simulated and measured 

streamflow at the streamflow-gaging station nearest to the 

outlet, station 05412500, shows that for the calibration period 

(October 1, 2002, through September, 30, 2012) model output 

estimates peak timing and volumes well; however, peak flow 

volumes tend to be underestimated (fig. 5). As with the Yellow River Basin model, the Turkey River Basin model also 

underestimates peak flow events that happen during the winter 

months (January, February, and March). 

The Maquoketa River Basin PRMS model exceeds 

the minimum criteria for satisfactory fit or for streamflow 

estimation in all streamflow-gaging stations except at station 05416900. A comparison of simulated and measured 

streamflow at the streamflow-gaging station nearest to the 

outlet, station 05418500, shows that for the calibration period 

(October 1, 2002, through September, 30, 2012) model output 

estimates peak timing and volumes well; however, peak flow 

volumes during lower flows tend to be overestimated, whereas 

peak flow volumes during higher flows tend to be underestimated. (table 3; fig. 5). 

The Wapsipinicon River Basin PRMS model meets the 

criteria for satisfactory fit or better for streamflow estimation 

in all streamflow-gaging stations except at station 05420560. 

A comparison of simulated and measured streamflow at 

the streamflow-gaging station nearest to the outlet, station 

05422000, indicates that for the calibration period (October 1, 

2002, through September, 30, 2012) model output estimates 

timing of peak flows well; however, peak flow volumes during 

lower flows tend to be overestimated, whereas peak flow volumes during higher flows tend to be underestimated (table 3; 

fig. 5).

The Iowa River Basin PRMS model also exceeds the 

minimum criteria for satisfactory fit or for streamflow estimation in all but 9 of the 32 streamflow-gaging stations (table 3). 

A comparison of simulated and measured streamflow at the 

streamflow-gaging stations 05453100 and 05465000 indicates that for the calibration period (October 1, 2002, through 

September, 30, 2012) model output estimates peak flow 

timing well (table 3; fig. 5). Peak flow volumes are generally 

underestimated.

The Skunk River Basin PRMS model also meets the 

criteria for satisfactory fit or better for streamflow estimation 

in all streamflow-gaging stations (table 3). A comparison of 

simulated and measured streamflow at the streamflow-gaging 

station nearest to the outlet, station 05474000, indicates that 

for the calibration period (October 1, 2002, through September, 30, 2012) model output estimates peak timing and 

volumes well; however, peak flow volumes during lower flows 

tend to be overestimated, whereas peak flow volumes during 

higher flows tend to be underestimated (table 3; fig. 5). 

 The Des Moines River Basin PRMS model exceeds the 

minimum criteria for satisfactory fit or for streamflow estimation in all but 9 of the 29 streamflow-gaging stations (table 3). 

A comparison of simulated and measured streamflow at station 

05484500 on the Raccoon River indicates that for the calibration period (October 1, 2002 through September, 30, 2012) 

model output estimates peak flow timing and volumes well, 

however peak flow volumes are generally overestimated. A 

comparison of simulated and measured streamflow at station 05481300 on the Des Moines River shows that for the 

calibration period (October 1, 2002, through September, 30, 

2012) model output estimates peak flow timing and volumes 

well; however, peak flow volumes during lower flows tend to 

be overestimated, whereas peak flow volumes during higher 

flows tend to be underestimated (table 3; fig. 5).

The Fox River Basin PRMS model meets the criteria for 

satisfactory fit or better for streamflow estimation at one of the 

two streamflow-gaging stations, the streamflow-gaging station 

nearest to the outlet, station 05495000. For the calibration 
22 Simulation of Daily Streamflow for Nine River Basins in Eastern Iowa Using the Precipitation-Runoff Modeling System 

0

WY2002 WY2003 WY2004 WY2005 WY2006 WY2007 WY2008 WY2009 WY2010 WY2011 WY2012

05412500 Turkey River at Garber, Iowa 

Streamflow, in cubic feet per second

20,000

30,000

40,000

50,000

60,000

10,000

Date (Water year, October 1 through September 30)

0

2,000

3,000

4,000

5,000

6,000

7,000

05389000 Yellow River near Ion, Iowa 

1,000

0

10,000

15,000

20,000

25,000

30,000

05388250 Upper Iowa River near Dorchester, Iowa 

5,000

Measured flow

Simulated flow

EXPLANATION

Measured flow

Simulated flow

EXPLANATION

Measured flow

Simulated flow

EXPLANATION

Figure 5. A comparison of measured and simulated flow (October 1, 2002, through September 30, 2012) at selected U.S. Geological 

Survey streamflow-gaging stations used in calibrating Precipitation-Runoff Modeling System models of nine river basins in eastern 

Iowa, water years (WYs) 2002–12.
Simulation of Daily Streamflow for Nine River Basins in Eastern Iowa Using the Precipitation-Runoff Modeling System 23

0

WY2002 WY2003 WY2004 WY2005 WY2006 WY2007 WY2008 WY2009 WY2010 WY2011 WY2012

05453100 Iowa River at Marengo, Iowa 

Streamflow, in cubic feet per second

20,000

30,000

40,000

50,000

60,000

10,000

Date (Water year, October 1 through September 30)

0

10,000

15,000

20,000

25,000

30,000

05422000 Wapsipinicon River near De Witt, Iowa 

5,000

40,000

35,000

0

10,000

15,000

20,000

25,000

30,000

05418500 Maquoketa River near Maquoketa, Iowa 

5,000

40,000

35,000

Measured flow

Simulated flow

EXPLANATION

Measured flow

Simulated flow

EXPLANATION

Measured flow

Simulated flow

EXPLANATION

Figure 5. A comparison of measured and simulated flow (October 1, 2002, through September 30, 2012) at selected U.S. Geological 

Survey streamflow-gaging stations used in calibrating Precipitation-Runoff Modeling System models of nine river basins in eastern 

Iowa, water years (WYs) 2002–12.—Continued
24 Simulation of Daily Streamflow for Nine River Basins in Eastern Iowa Using the Precipitation-Runoff Modeling System 

0

20,000

30,000

40,000

50,000

60,000

05481300 Des Moines River near Stratford, Iowa 

10,000

WY2002 WY2003 WY2004 WY2005 WY2006 WY2007 WY2008 WY2009 WY2010 WY2011 WY2012

Streamflow, in cubic feet per second

Date (Water year, October 1 through September 30)

0

10,000

15,000

20,000

25,000

30,000

05474000 Skunk River at Augusta, Iowa 

5,000

0

40,000

60,000

80,000

100,000

120,000

05465000 Cedar River near Conesville, Iowa 

20,000

Measured flow

Simulated flow

EXPLANATION

Measured flow

Simulated flow

EXPLANATION

Measured flow

Simulated flow

EXPLANATION

Figure 5. A comparison of measured and simulated flow (October 1, 2002, through September 30, 2012) at selected U.S. Geological 

Survey streamflow-gaging stations used in calibrating Precipitation-Runoff Modeling System models of nine river basins in eastern 

Iowa, water years (WYs) 2002–12.—Continued
Simulation of Daily Streamflow for Nine River Basins in Eastern Iowa Using the Precipitation-Runoff Modeling System 25

0

5,000

10,000

15,000

20,000

25,000

WY2002 WY2003 WY2004 WY2005 WY2006 WY2007 WY2008 WY2009 WY2010 WY2011 WY2012

05495000 Fox River at Wayland, Iowa 

Streamflow, in cubic feet per second

Date (Water year, October 1 through September 30)

0

20,000

30,000

40,000

50,000

60,000

05484500 Racoon River at Van Meter, Iowa 

10,000

Measured flow

Simulated flow

EXPLANATION

Measured flow

Simulated flow

EXPLANATION

Figure 5. A comparison of measured and simulated flow (October 1, 2002, through September 30, 2012) at selected U.S. Geological 

Survey streamflow-gaging stations used in calibrating Precipitation-Runoff Modeling System models of nine river basins in eastern 

Iowa, water years (WYs) 2002–12.—Continued
26 Simulation of Daily Streamflow for Nine River Basins in Eastern Iowa Using the Precipitation-Runoff Modeling System 

period (October 1, 2002, through September, 30, 2012), the 

model output estimates peak flow timing well, but tends 

to underestimate peak flow volumes, and overestimate and 

poorly characterize base flow volumes (table 3; fig. 5).

Overall, the PRMS models of nine river basins in eastern 

Iowa constructed for this investigation satisfactorily estimate 

daily streamflow at 57 of the 79 calibration and 13 of the 

14 validation gaged sites as indicated by the NSE, R2, PBIAS, 

and RSR values presented in table 3. In general, gaged sites 

in headwater subbasins with small drainage areas and streamflows tended to have less accuracy than the main-stem gaged 

sites with larger drainage areas and streamflows. The graphs of 

measured and simulated values at selected USGS streamflowgaging stations within the basins show that the models indicate 

that unsatisfactory performance may be attributed to several 

factors: (1) low flow, no flow, and flashy flow conditions in 

headwater subbasins having a small drainage area; (2) poor 

representation of the groundwater and storage components of 

flow within a basin; (3) lack of accounting for basin withdrawals and water use; and (4) the availability and accuracy of 

meteorological input data. In addition, streamflow is simulated at a daily time step, so shorter-duration, flashy streamflow events are not well represented. A more robust subdaily 

modeling routine may be necessary at the smaller headwater 

subbasins to accurately reflect flashy, subdaily climatic events. 

Further refinement and calibration with more detailed information on groundwater and subsurface storage, water use, and 

local precipitation and temperature would better guide the 

proper modeling of low and peak flows and improve model 

performance.

As indicated in the statistical results at validation gaged 

sites (which evaluate the accuracy of the model at potential 

ungaged sites), calibrated models can provide satisfactory 

streamflow estimates throughout the nine river basins in eastern Iowa, at a model HRU and stream segment scale (table 3). 

The PRMS models provide a consistent and documented 

method for streamflow estimation at locations within the basin 

that may not have available USGS streamflow-gaging station 

information. 

Model Limitations

The PRMS model uses parameters generated by the GIS 

Weasel that are dependent upon soil and land cover input 

datasets (see “Delineation and Parameterization of Spatial 

Features”). These datasets are dated, have variable degrees of 

resolution, and may not reflect current land cover or land use 

conditions in parts of the study area. These inaccuracies may 

contribute to the overestimation or underestimation of streamflow by the PRMS model.

The PRMS model depends on the use of meteorological datasets to drive the model computations to simulate 

streamflow. In this study, a network of meteorological stations was used to derive precipitation and temperature model 

inputs. The spatial distribution of the meteorological stations 

used to interpolate the spatial distribution of temperature and 

precipitation within the nine river basins in eastern Iowa is 

shown in figure 4. Temperature and precipitation can vary 

over small distances; this variability may not be captured by 

meteorological stations; for example, summer thunderstorm 

activity can produce rapid changes in temperature and a large 

amount of precipitation in a small area. Summer thunderstorm 

activity can be missed if there is no meteorological station in 

the area; thus, the lack of accurate meteorological data over 

each basin could have contributed to the underestimation or 

overestimation of daily streamflow. The use of a more robust 

spatial distribution of climatic data such as Next Generation 

Radar (NEXRAD), a product of the National Weather Service 

(NWS), may aid in improving climatic calculations that are the 

driving forces of the PRMS model (Kalin and Hantush, 2006). 

There are several notable limitations in the PRMS 

models. First, the PRMS models have a daily time step that 

has all flows and storages expressed as daily mean values. 

Because of this, error may result because of the daily averaging of near land-surface flows, or when streamflow changes 

during subdaily time increments (Markstrom and others, 

2012). Second, flows and storages are assumed to be homogeneous within each HRU, and some hydrologic complexity 

and parameter variability within an HRU may be lost. Third, 

the method of simulating solar radiation values for each HRU 

does not account for variations in solar activity or changes in 

atmospheric events. This limitation, however, typically results 

in only small changes in solar radiation, which have a minimal effect on hydrologic variables and projected basin runoff 

(Markstrom and others, 2012). Fourth, there are complications 

in simulations when rain falls on the snowpack in excess of its 

available pore space. Either the water will runoff the snowpack, in which case it is erroneously considered as snowmelt, 

or the water will freeze to the snowpack causing the model 

to later report more snowmelt than snowfall (Markstrom and 

others, 2012). Both of these cases may complicate interpretation of the model with regard to rain on snowpack events. 

This study used the Jensen-Haise method (Jensen and others 

1970; and Markstrom and others, 2008) to estimate stationary 

monthly mean values for potential evapotranspiration (PET) 

at each calibration point for subbasin calibration, which may 

be a source of uncertainty in the model. Studies (Kingston and 

others, 2009; and Donohue and others, 2010) show that this 

uncertainty is reduced because PRMS uses simulated PET, 

vegetation type, land-use characteristics, soil type, simulated atmospheric conditions, and soil moisture availability 

to compute actual evapotranspiration (AET), and it is AET 

that PRMS used in the water balance simulation (Markstrom 

and others, 2008; and Markstrom and others, 2012). A more 

detailed discussion of PET uncertainty in the PRMS model is 

presented in Markstrom and others (2012).
References Cited 27

Summary

The U.S. Geological Survey (USGS) maintains about 

149 real-time streamflow-gaging stations in Iowa where daily 

mean streamflow information is available. This streamflow 

information provides the basis for understanding the hydrologic characteristics of basins and, in combination with waterquality information collected at a monthly time step at 75 locations across the State by State and Federal agencies, aids in 

understanding risks imposed on human and ecosystem health. 

Because the information collected at these streamflow-gaging 

stations is site specific, the ability to confidently use these data 

to infer streamflow information at ungaged sites within a basin 

for adaptive management and decisions can be limited. Hydrological models are one tool that can be used to overcome 

this limitation in eastern Iowa. Precipitation-Runoff Modeling System (PRMS) models were constructed in cooperation 

with the Iowa Department of Natural Resources for nine river 

basins in eastern Iowa as part of an ongoing research project to 

examine methods of estimating daily streamflow at gaged and 

ungaged sites. 

The PRMS models were constructed for a total of nine 

river basins in eastern Iowa that are each a tributary to the 

Mississippi River: Upper Iowa River Basin, Yellow River 

Basin, Turkey River Basin, Maquoketa River Basin, Wapsipinicon River Basin, Iowa River Basin, Skunk River Basin, Des 

Moines River Basin, and Fox River Basin. The construction, 

calibration, and evaluation of PRMS basin models to simulate 

daily streamflows and hydrologic components for river basins 

in eastern Iowa were described. Model performance was 

assessed to determine the ability of PRMS to estimate streamflow and the suitability for models to serve as part of a suite 

of methods for estimating daily streamflow at ungaged sites. 

Model limitations were investigated and described.

The PRMS is a modular, distributed-parameter, physicalprocess basin model developed to evaluate the effects of 

various combinations of precipitation, climate, and land use 

on surface-water runoff. The PRMS simulates the hydrologic 

system with known physical laws and empirical relations 

derived from basin characteristics. The nine river basins in 

eastern Iowa were delineated with the GIS Weasel. The GIS 

Weasel was used to characterize the physical features of each 

river basin in eastern Iowa into the requisite sets of parameters 

for input into PRMS.

Precipitation, minimum temperature, and maximum temperature were used in the PRMS models of nine river basins 

in eastern Iowa as the main climatic drivers. In addition to 

meteorological inputs, PRMS can also use streamflow-gaging 

station data in place of simulated streamflow. The USGS 

streamflow-gaging station data and meteorological datasets for 

precipitation and temperature were collected using the USGS 

Downsizer program. The PRMS model was calibrated using 

the Luca program, which is a multiple-objective, stepwise 

procedure. Calibration and validation periods used in each 

basin mostly were October 1, 2002, through September 30, 

2012, but differed depending on the period of record available 

for daily mean streamflow measurements at U.S. Geological 

Survey streamflow-gaging stations. 

Overall, PRMS models of nine river basins in eastern 

Iowa constructed for this investigation satisfactorily estimate 

daily streamflow at 57 of the 79 calibration and 13 of the 

14 validation gaged sites as indicated by the NSE, R2, PBIAS, 

and RSR values. Unsatisfactory performance may be attributed to several factors: (1) low flow, no flow, and flashy flow 

conditions in headwater subbasins having a small drainage 

area; (2) poor representation of the groundwater and storage 

components of flow within a basin; (3) lack of accounting for 

basin withdrawals and water use; and (4) the availability and 

accuracy of meteorological input data. In addition, the version 

of PRMS used for this study will average a short-duration, 

flashy streamflow event during a daily time step, whereas a 

more robust subdaily modeling routine may be necessary at 

the smaller headwater subbasins to accurately reflect flashy, 

subdaily climatic events. Further refinement and calibration 

with more detailed information would better guide the proper 

modeling of these flow components and improve model 

performance.

The PRMS models of nine river basins in eastern Iowa 

can provide satisfactory streamflow estimates at model HRU 

and stream segment scale. The PRMS models will provide 

a consistent and documented method for estimating streamflow at locations within the basin that may not have available 

USGS streamflow-gaging station information.

References Cited

Christiansen, D.E., 2012, Simulation of daily streamflows 

at gaged and ungaged locations within the Cedar River 

Basin, Iowa, using a Precipitation-Runoff Modeling System 

model: U.S. Geological Survey Scientific Investigations 

Report 2012–5213, 20 p. [Also available at http://pubs.usgs.

gov/sir/2012/5213/.]

Donohue, R.J., McVicar, T.R., and Roderick, M.L., 2010, 

Assessing the ability of potential evaporation formulations 

to capture the dynamics in evaporative demand within a 

changing climate: Journal of Hydrology, v. 386, no. 1–4, 

p. 186–197. [Also available at http://dx.doi.org/10.1016/j.

jhydrol.2010.03.020.]

Duan, Q.Y., Gupta, V.K., and Sorooshian, Soroosh, 1993, 

Shuffled complex evolution approach for effective and efficient global minimization: Journal of Optimization Theory 

and Applications, v. 76, no. 3, p. 501–521. [Also available 

at http://dx.doi.org/10.1007/BF00939380.]
28 Simulation of Daily Streamflow for Nine River Basins in Eastern Iowa Using the Precipitation-Runoff Modeling System 

Dudley, R.W., 2008, Simulation of the quantity, variability, and timing of streamflow in the Dennys River Basin, 

Maine, by use of a precipitation-runoff watershed model: 

U.S. Geological Survey Scientific Investigations Report 

2008–5100, 44 p. [Also available at http://pubs.usgs.gov/

sir/2008/5100/.]

Gassman, P.W., Reyes, M.R., Green, C.H., and Arnold, J.G., 

2007, The soil and water assessment tool—Historical 

development, applications, and future research directions: 

Transactions of the American Society of Agricultural and 

Biological Engineers, v. 50, no. 4, p. 1211–1250. [Also 

available at http://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs143_013639.pdf.]

Goode, D.J., Koerkle, E.H., Hoffman, S.A., Regan, R.S., Hay, 

L.E., and Markstrom, S.L., 2010, Simulation of runoff and 

reservoir inflow for use in a flood-analysis model for the 

Delaware River, Pennsylvania, New Jersey, and New York, 

2004–2006: U.S. Geological Survey Open-File Report 

2010–1014, 68 p. [Also available at http://pubs.usgs.gov/

of/2010/1014/.]

Gupta, H.V., Sorooshian, Soroosh, and Yapo, P.O., 1999, 

Status of automatic calibration for hydrologic models—

Comparison with multilevel expert calibration: Journal 

of Hydrologic Engineering, v. 4, no. 2, p. 135–143. [Also 

available at http://dx.doi.org/10.1061/(ASCE)1084-

0699(1999)4:2(135).]

Haj, A.E., Christiansen, D.E., and Viger, R.J., 2014, The 

effects of Missouri River mainstem reservoir system 

operations on 2011 flooding using a Precipitation-Runoff 

Modeling System model: U.S. Geological Survey Professional Paper 1798–K, 33 p. [Also available at http://dx.doi.

org/10.3133/pp1798K.]

Hay, L.E., and Umemoto, Makiko, 2006, Multiple-objective 

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Publishing support provided by: 

Rolla Publishing Service Center

For more information concerning this publication, contact:

Director, USGS Iowa Water Science Center

P.O. Box 1230

Iowa City, IA 52244

(319) 337–4191

Or visit the Iowa Water Science Center Web site at:

http://ia.water.usgs.gov/

Haj and others—Simulation of Daily Streamflow for Nine River Basins in Eastern Iowa Using the Precipitation-Runoff Modeling System —SIR 2015–5129

ISSN 2328-0328 (online)

http://dx.doi.org/10.3133/sir20155129