Estimated Flood-Inundation Mapping 

for the Lower Blue River in Kansas City,

Missouri, 2003–05

Prepared in cooperation with the City of Kansas City, Missouri 

U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2006–5089
Cover: Blue River at 63rd Street, Kansas City, Missouri, on May 19, 2004 (left). Photograph courtesy of Paul H. Rydlund, Jr., 

U.S. Geological Survey. Flood-inundation map example for the lower Blue River, Kansas City, Missouri, between I-70 and 

12th Street (right).
Estimated Flood-Inundation Mapping for 

the Lower Blue River in Kansas City, 

Missouri, 2003–05

By Brian P. Kelly and Paul H. Rydlund, Jr.

U.S. Department of the Interior

U.S. Geological Survey

Prepared in cooperation with the City of Kansas City, Missouri

Scientific Investigations Report 2006–5089
U.S. Department of the Interior

P. Lynn Scarlett, Acting Secretary

U.S. Geological Survey

P. Patrick Leahy, Acting Director

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

For sale by U.S. Geological Survey, Information Services

Box 25286, Denver Federal Center

Denver, CO 80225

For more information about the USGS and its products:

Telephone: 1-888-ASK-USGS

World Wide Web: http://www.usgs.gov/

Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply 

endorsement by the U.S. Government.

Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report.

ISBN

Suggested citation:

Kelly, B.P., and Rydlund, P.H., Jr., 2006. Estimated Flood-Inundation Mapping for the Lower Blue River in Kansas City, 

Missouri, 2003–05: U.S. Geologic al Survey Scientific Investigations Report 2006–5089, 27 p.
 iii

Contents

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

Introduction

Purpose and Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Study Area Description

Two-Dimensional Model Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Study Reach Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

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

Model Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Development of Simulated Rating Using One-Dimensional Hydraulic Analysis . . . . . . . . . . . . . . . . . . . . . . . . 13

Simulated Velocity Magnitude and Direction Flood-Inundation Maps. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Estimated Flood-Inundation Mapping. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Estimated Flood-Inundation Mapping Benefits and Limitations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Blue River Estimated Flood-Inundation Maps on the World Wide Web. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

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

References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Appendixes

1. Velocity magnitude and direction maps—63rd Street

2. Velocity magnitude and direction maps—Mid Reach

3. Velocity magnitude and direction maps—Blue Parkway

4. Estimated flood-inundation maps

5. Estimated Missouri River backwater-inundation maps

Figures

1–9. Maps showing:

1. Study area, National Weather Service flood-forecast locations, and channel

improvement limit . . . . . . . . . 

2. Land-surface elevation of the study area

3. Simulated study reach of the Blue River between 63rd Street and Blue Parkway. . . . . . . . . .

4. Land-use coverage used in flow simulations in the study reach. . . . . . . . . . . . .

5. Finite-element mesh incorporating pier configuration for current (2005) Blue Parkway

Bridge and downstream lower Blue Parkway Bridge for the model calibration flood of 

May 19, 2004.

6. Modified finite-element mesh based on pier configuration of the proposed Blue 

Parkway structure.

7. Simulated velocity magnitude for the May 19, 2004, flood. . . . . . . . . . . . . 

8. Simulated water depth for the May 19, 2004, flood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9. Simulated stage elevation and high-water observation for the May 19, 2004, flood. . . . . . . . . . . 16

 15

. . . . . . . . . . . . . . . . . . . . . . . 14

 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

. . . . . . . . . . . . . . . . 10

 . . . .7

 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
iv 

Figures—Continued

10. Cross sections used in the constructed HEC-RAS model. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

11. Graph showing calculated Blue River slopes, stage elevations, cross sections, and sources

of data for all flood-inundation maps from Gregory Boulevard to the mouth of the Blue River . . . . . . 21

12–13. Maps showing:

12. Location of cross sections used for flood-inundation area interpolation and the area of the

constructed FESWMS model used to create flood-inundation surfaces. . . . . . . . . . . . . . . . . . . . . . . . . . . 22

13. Regions and sections of the Blue River flood-inundation maps associated with each

forecast location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Tables

1. Forecast location, zero datum, flood-gage height, and local flood impacts. . . . . . . . . . . . . . . . . . . . . . . . . . .4

2. Manning’s n roughness coefficients for the calibrated model run. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

3. Measured and simulated stage elevation, cross-sectional area, and velocity . . . . . . . . . . . . . . . . . . . . . 13

4. Measured and simulated conditions for the constructed HEC-RAS model . . . . . . . . . . . . . . . . . . . . . . . . 17

5. Energy grade line (EGL) slope for Kansas City U.S. Army Corps of Engineers HEC-RAS model of the 

lower Blue River and HEC-RAS model constructed between the lower Blue River model and the study 

reach for selected flood-frequency values. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

6. Simulated rating depicting stage elevation at the lower Blue Parkway Bridge and discharge as 

boundary conditions for developed flood-inundation maps in the study reach. . . . . . . . . . . . . . . . . . . . . 18

7. Equivalent peak flood-stage elevation and gage heights for forecast locations for flood inundation on 

the Blue River . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

8. Equivalent flood-stage elevation and gage heights for forecast locations for Missouri River 

backwater inundation of the Blue River . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
 v

Conversion Factors and Datum

Multiply By To obtain

Length

inch (in.)

foot (ft)

mile (mi)

2.54

 0.3048

 1.609

centimeter (cm)

meter (m)

kilometer (km)

Area

square foot (ft2)

square mile (mi

2)

 0.09290

 2.590

square meter (m2)

square kilometer (km2)

Flow rate

foot per second (ft/s)

foot per mile (ft/mi)

square foot per second (ft2/s)

cubic foot per second (ft

3/s)

 0.3048

0.1894

 0.0929

2446.6

meter per second (m/s)

meter per kilometer (m/km)

square meter per second (m2/s)

cubic meter per day (m3/d)

Hydraulic gradient

foot per mile (ft/mi) 0.1894 meter per kilometer (m/km)

Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as follows:

°C = (°F - 32) / 1.8

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

Elevation, as used in this report, refers to distance above the National Geodetic Vertical Datum 

of 1929 (NGVD 29)—A geodetic datum derived from a general adjustment of the first-order level 

nets of both the United States and Canada, formerly called Sea Level Datum of 1929.
vi 
Estimated Flood-Inundation Mapping for the Lower Blue 

River in Kansas City, Missouri, 2003–05

By Brian P. Kelly and Paul H. Rydlund, Jr.

Abstract

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

of Kansas City, Missouri, began a study in 2003 of the lower 

Blue River in Kansas City, Missouri, from Gregory Boulevard 

to the mouth at the Missouri River to determine the estimated 

extent of flood inundation in the Blue River valley from flooding on the lower Blue River and from Missouri River backwater. Much of the lower Blue River flood plain is covered by 

industrial development. Rapid development in the upper end of 

the watershed has increased the volume of runoff, and thus the 

discharge of flood events for the Blue River. Modifications to 

the channel of the Blue River began in late 1983 in response to 

the need for flood control. By 2004, the channel had been widened and straightened from the mouth to immediately downstream from Blue Parkway to convey a 30-year flood. 

A two-dimensional depth-averaged flow model was used 

to simulate flooding within a 2-mile study reach of the Blue 

River between 63rd Street and Blue Parkway. Hydraulic simulation of the study reach provided information for the design 

and performance of proposed hydraulic structures and channel 

improvements and for the production of estimated flood-inundation maps and maps representing an areal distribution of 

water velocity, both magnitude and direction. 

Flood profiles of the Blue River were developed between 

Gregory Boulevard and 63rd Street from stage elevations calculated from high water marks from the flood of May 19, 2004; 

between 63rd Street and Blue Parkway from two-dimensional 

hydraulic modeling conducted for this study; and between Blue 

Parkway and the mouth from an existing one-dimensional 

hydraulic model by the U.S. Army Corps of Engineers. Twelve 

inundation maps were produced at 2-foot intervals for Blue 

Parkway stage elevations from 750 to 772 feet. Each map is 

associated with National Weather Service flood-peak forecast 

locations at 63rd Street, Blue Parkway, Stadium Drive, U.S. 

Highway 40, 12th Street, and the Missouri River at the Hannibal 

railroad bridge in Kansas City. The National Weather Service 

issues peak-stage forecasts for these locations during times of 

flooding. Missouri River backwater inundation profiles were 

developed using interpolated Missouri River stage elevations at 

the mouth of the Blue River. Twelve backwater-inundation 

maps were produced at 2-foot intervals for the mouth of the 

Blue River from 730.9 to 752.9.

To provide public access to the information presented in 

this report, a World Wide Web site (http://mo.water.usgs.gov/

indep/kelly/blueriver/index.htm) was created that displays the

results of two-dimensional modeling between 63rd Street and 

Blue Parkway, estimated flood-inundation maps, estimated 

backwater-inundation maps, and the latest gage heights and 

National Weather Service stage forecast for each forecast 

location within the study area. In addition, the full text of this 

report, all tables, and all plates are available for download at 

http://pubs.water.usgs.gov/sir2006-5089.

Introduction

The Blue River flows through the middle of Kansas City to 

its mouth at the Missouri River (fig. 1) and has been a source of 

flood damage in Kansas City for many years. Flooding in the 

Blue River Basin has caused millions of dollars of damage (U.S. 

Geological Survey, 1952; National Oceanic and Atmospheric 

Administration, 1977; Hauth and Carswell, 1978; Becker and 

Alexander, 1983) and has resulted in the deaths of more than 26 

people in the last 25 years. The National Weather Service 

(NWS) in Kansas City provides a flood peak prediction service 

at the Missouri River and five forecast locations in the study 

area (fig. 1). Although this information is useful for residents 

within the vicinity of a NWS station, it is of limited use to residents upstream and downstream because the stage elevation is 

not flat (Studley, 2003). In this report, stage is a generic term for 

river level, or river level in terms of gage height, and stage elevation is the elevation of the river surface above the National 

Geodetic Vertical Datum of 1929 (NGVD 29). Despite the 

known hazards of flooding, Federal Emergency Management 

Agency (FEMA), city of Kansas City, and State emergency 

management mitigation teams typically lack information 

related to the location, depth, and velocities of water in inundated areas during and after floods. Flood-inundation mapping 

frequently is done long after major floods (U.S. Geological Survey, 1952; Perry, 1994) and often is of marginal use to recovery 

efforts. However, in recent years the convergence of major 

technological advances in real-time streamflow information, 

flood prediction, availability of 1- and 2-ft (foot)-contour-interval topographic maps, two-dimensional hydraulic modeling, 

and geographic information systems (GIS) technology now 

makes World Wide Web based delivery of real-time stage infor-
2 Estimated Flood-Inundation Mapping for the Lower Blue River in Kansas City, Missouri, 2003–05

MISSOURI RIVER

Blue River

63rd Street

Gregory Boulevard

Blue

12th Street

Stadium

70

70

435

435

40

Drive

Parkway

#

#

#

#

#

#

U.S. Geological Survey

stage gage at 12th Street 

(06893590)

U.S. Geological Survey 

streamflow gage 

at Stadium Drive

(06893578)

Kansas City, Missouri, 

ALERT gage at 63rd Street 

Kansas City, Missouri,

 ALERT gage at Blue Parkway

National Weather Service 

flood-forecast location at 

Highway 40

U.S. Geological Survey streamflow gage, 

Missouri River at Kansas City, Missouri

(06893000)

Brush Creek 

94°34' 94°32' 94°30' 94°28'

39°00'

39°02'

39°04'

39°06'

39°08'

39°10'

EXPLANATION

#

0 1 2 MILES

0 1 2 KILOMETERS

Figure 1. Study area, National Weather Service flood-forecast locations, and channel improvement limit.

STUDY AREA

GAGE OR FLOOD-FORECAST LOCATION

 (ALERT, Automated Local Evaluation in Real Time)

Base from U.S. Geological Survey digital data, 1:24,000, 1996

Universal Transverse Mercator projection, Zone 15

Horizontal coordinate information is referenced to the 

North American Datum of 1983 (NAD83)

MISSOURI

Study

area

Channel improvement upstream limit
Study Area Description 3

mation, flood forecast prediction, and estimated flood-inundation maps possible. 

The Kansas City U.S. Army Corps of Engineers (USACE) 

was authorized by Congress in 1970 to modify the Blue River 

channel from the mouth at the Missouri River southward 

(upstream) to 63rd Street. The primary emphasis of the project 

was to increase hydraulic capacity, thereby providing flood 

damage reduction in the Blue River valley. The upstream limit 

of channel improvement is currently (2005) located approximately 1,240 ft upstream from Brush Creek (approximately 

1,250 ft downstream from the study reach) (fig. 1). Contingent 

upon funding, the remaining reach of Blue River upstream to 

63rd Street also may be channelized (http://

www.nwk.usace.army.mil/projects/blueriver/status.htm). A 

detailed two-dimensional hydraulic simulation was needed in 

the study reach between 63rd Street and Blue Parkway to provide flood-plain water velocities and depths for the design and 

performance of proposed hydraulic structures and existing 

flood-plain developments, along with the production of floodinundation maps and maps representing an areal distribution of 

water velocity, both magnitude and direction. 

To address these needs, the USGS, in cooperation with the 

city of Kansas City, Missouri, began a study in 2003 of the Blue 

River from Gregory Boulevard to the mouth to determine the 

extent and character of inundation in the Blue River valley from 

flooding in the lower Blue River and backwater from the Missouri River for selected stage elevations above flood stage. The 

results of this study supplement information provided by USGS 

gages, Kansas City ALERT (Automated Local Evaluation in 

Real Time) gages, and the NWS flood peak prediction service 

that comprise the Blue River flood-alert system and represent a 

valuable tool for public officials and residents to minimize 

flood deaths and damage in Kansas City. 

Purpose and Scope 

The purpose of this report is to describe estimated floodinundation mapping for the Lower Blue River. Methods used to 

construct, calibrate, and verify the two-dimensional hydraulic 

modeling of the Blue River between 63rd Street and Blue Parkway, to prepare estimated flood-inundation maps for the Blue 

River from Gregory Boulevard downstream to the mouth at the 

Missouri River, and to present estimated flood-inundation maps 

on the World Wide Web are described. Twelve velocity magnitude and direction maps are presented at 2-ft intervals above 

Blue River flood stage for the modeled area. Twelve Blue River 

flood-inundation maps and 12 Missouri River backwater-inundation maps are presented at 2-ft intervals above flood stage for 

the Blue River flood plain from Gregory Boulevard downstream to the mouth. 

Acknowledgments 

The following are acknowledged for their support of this 

study: the city of Kansas City—Parks and Recreation for providing access to the Blue River for flood measurement; the Kansas City U.S. Army Corps of Engineers for providing channel 

bathymetry, construction data, and one-dimensional model 

results of the improved Blue River channel; and the NWS Forecast Office—Kansas City/Pleasant Hill for providing peak 

flood stages at flood-forecast locations and historical peak stage 

information. 

Study Area Description 

The study area includes the Blue River flood plain from 

Gregory Boulevard north to the mouth of the Blue River at the 

Missouri River (fig. 1). Within the study area, the length of the 

Blue River flood plain is about 10.6 mi (miles), and the actual 

length of the Blue River is about 15.5 mi. The stage elevation of 

the Blue River at normal stage decreases about 47 ft from Gregory Boulevard to the mouth. 

The local climate is characterized by large variations and 

sudden changes in temperature and precipitation. The average 

temperature in January, the coldest month, is 26.9 °F (degrees 

Fahrenheit) and the average temperature in July, the hottest 

month, is 78.5 °F. Average annual precipitation is 38 in. 

(inches); almost 68 percent of the precipitation occurs between 

April and September (National Oceanic and Atmospheric 

Administration, 2003). An estimate of the 90 percent rainfall 

event for the Kansas City area (the 90th percentile daily rainfall 

accumulation, excluding accumulations less than 0.1 in.) is 1.37 

in. (Young and McEnroe, 2002). 

Much of the lower Blue River flood plain is covered by 

industrial development. Rapid development in the upper end of 

the watershed has increased the volume of runoff, and thus the 

discharge of flood events for the Blue River. The small size of 

the basin [275 mi2 (square miles)] causes flash floods and 

allows minimal time for flood forecasting and response. Modifications to the channel of the Blue River began in late 1983 in 

response to the need for flood control. By 2004, the channel had 

been widened and straightened from the mouth at the Missouri 

River to immediately downstream from Blue Parkway (fig. 1). 

Channel modifications were designed to convey a 30-year 

flood. 

Because of the large number of people and businesses 

along the Blue River, the NWS issues peak-stage forecasts for 

five gage locations in the study area and for the Missouri River 

at Kansas City (fig. 1) during high water. Current river stage 

and peak-stage forecasts are presented on the NWS Advanced 

Hydrologic Prediction Service internet site at http://

www.weather.gov/ahps/. The NWS forecast locations in the 

study area on the Blue River, in order from upstream to downstream are the Kansas City ALERT gage on the Blue River at 

63rd Street, the Kansas City ALERT gage on the Blue River at
4 Estimated Flood-Inundation Mapping for the Lower Blue River in Kansas City, Missouri, 2003–05

Blue Parkway, the USGS streamflow gage on the Blue River at 

Stadium Drive (station number 06893578), the NWS forecast 

location on the Blue River at U.S. Highway 40, and the USGS 

stage-only gage on the Blue River at 12th Street (station number 

06893590). The forecast location for the Missouri River is the 

USGS streamflow gage on the Missouri River at Kansas City 

(station number 06893000). Forecast location name, zero gage 

datum, flood gage height, and local impacts for selected flood 

gage heights are listed in table 1. 

Table 1. Forecast location, zero datum, flood-gage height, and local flood impacts.

[ft, feet; NGVD 29, National Geodetic Vertical Datum of 1929; USGS, U.S. Geological Survey; NA, not applicable]

Forecast location name

Zero gage 

datum (ft) 

(NGVD 29)

Flood gage 

height 

(ft)1,2 Local flood impacts1

Kansas City ALERT Gage at 63rd Street 721.78 48.0 Low-lying areas in the vicinity of 63rd Street begin to flood.

49.0 Water approaches 59th Street.

52.3 Water enters a manufacturing plant on Colorado Street.

 55.6 Water approaches the railroad tracks on the west side of the river.

Kansas City ALERT Gage at Blue Parkway 722.47 33.4 The lower Blue Parkway floods on the west side of the river.

 38.1 The lower Blue Parkway floods east of the lower bridge.

 38.2 Brighton Avenue near Blue Parkway floods.

 39.0 Hardesty Street at 51st Street floods. 

 40.7 The lower Blue Parkway Bridge is flooded.

 44.0 Flood waters approach the first floors of the businesses near the Blue River.

USGS Streamflow Gage—Blue River at Stadium 

Drive in Kansas City, Missouri

718.29 32.0 A low-lying area on the east side of the river near Stadium Drive begins to flood.

 35.2 Water reaches the bottom of the Stadium Drive Bridge.

36.4 Stadium Drive and Leeds Trafficway intersection is flooded.

 39.9 Water overtops the Stadium Drive Bridge. 

National Weather Service Forecast Location at 

U.S Highway 40 

721.65 30.0 Low-lying areas near U.S. Highway 40 are flooded.

 33.0 Water begins to flood a mobile home park on U.S. Highway 40.

USGS Stage Gage—Blue River at 12th Street in 

Kansas City, Missouri 

714.41 30.0 Low-lying areas near 12th Street flood. If the Missouri River is high, Blue River flood 

waters may approach the top of the flood wall on the west bank of the Blue River 

near the Wilson Avenue Bridge. 

36.1 12th Street floods 300 yards west of the bridge. 

36.8 Water overtops railroad tracks on the west side of the river. 

39.0 Water reaches the bottom of the 12th Street Bridge. 

51.0 Flood waters overtop the 12th Street Bridge. 
Two-Dimensional Model Application 5

Total relief of the flood plain within the study area is 

approximately 110 ft, and land-surface elevation ranges from 

more than 820 ft along the valley walls at the south end of the 

study area to about 710 ft at the mouth of the Blue River (fig. 2). 

Two-Dimensional Model Application

A depth-averaged flow model, Flo2DH, [part of the Federal Highway Administrations’s Finite Element Surface-Water 

Modeling System (FESWMS) designed for hydraulic structures 

and flood plains], was chosen to simulate steady-state flood 

flows within a hydraulically complex part of the Blue River 

reach. Two-dimensional modeling is beneficial in simulating 

flow around bends, piers, buildings, and encroaching hydraulic 

structures; flow within expanding and contracting reaches; and 

backwater effects on inflowing tributaries. The two-dimensional model was used to construct flood-inundation maps in 

the simulated reach. In addition, the model computes water 

velocity, flow direction, depth, and inundation extent within the 

flood plain. These model outputs can be useful in designing 

potential channel and flood-plain improvements throughout the 

simulated reach. 

Study Reach Description 

The hydraulically complex part of the Blue River between 

63rd Street and Blue Parkway (hereinafter referred to as the

“study reach”) is approximately 2 river miles long and consists 

of a deeply incised channel, sharp meander bends, small tributary junctions, and frequent riffles exhibiting substantial gradient change (fig. 3). The study reach is bordered on the west by 

the Union Pacific Railroad and on the east by Hardesty Avenue. 

The west and east limits of the study reach were pre-determined 

using hydraulic engineering judgement according to limits of 

substantial flow and velocity. The flood plain is representative 

of industrial land use mixed with small residential homes (fig. 

4). Aside from the thick riparian corridor along the Blue River, 

the western part of the flood plain is predominantly impervious; 

the eastern part of the flood plain consists of residential dwellings. Four small unnamed tributaries exist along the Blue River 

at the lower, middle, and upper end of the study reach (fig. 3). 

The tributaries have drainage areas between 1 and 2 mi2 and 

were not considered in the analysis because of limited contributions of flow at the time of main stem flooding. A 60-ft triple 

barrel concrete box culvert providing hydraulic connectivity to 

both sides of Brighton Avenue is present within the middle tributary that dissects the western part of the flood plain of the study 

reach (fig. 3). The channel of the middle tributary west of Brighton Avenue is inundated for high flow events because of backwater from the Blue River flooding. With time, the culvert 

essentially has become ineffective because of the infilling of silt 

and build up of debris within the barrels of the culvert. Byram’s 

Ford, a historic site from the Civil War, is located approximately 

2,800 ft downstream from the 63rd Street Bridge.

Model Development 

Two-dimensional modeling provides more hydraulic 

detail as compared to conventional one-dimensional analysis. 

The FESWMS Flo2DH model uses the Galerkin finite-element 

method as a numerical procedure for solving differential equations representing conservation of mass and momentum (Froehlich, 2002). A graphical interface known as Surface Water 

Modeling System (SMS, Environmental Modeling Systems

USGS Streamflow Gage—Missouri River at 

Kansas City

 706.40 32.0 Minor flooding outside of levees occurs. 

35.0 Farm levees are overtopped. Cropland, homesteads, and secondary roads behind the 

levees floods. 

39.0 Gaps in levees and floodwalls in the Central Industrial District must be closed. 

40.0 Gaps in the levees and floodwalls at North Kansas City must be closed. 

 43.7 Gaps in the levees and floodwalls of the East Bottoms area must be closed. 

48.5 The levee in the Birmingham Unit is overtopped. 

49.6 Major levees in the Kansas City, Missouri, area begin to overtop. 

1National Weather Service, 2005.

2

Add zero gage datum to gage height to convert gage height to stage elevation.

Table 1. Forecast location, zero datum, flood-gage height, and local flood impacts.—Continued

[ft, feet; NGVD 29, National Geodetic Vertical Datum of 1929; USGS, U.S. Geological Survey; NA, not applicable]

Forecast location name

Zero gage 

datum (ft) 

(NGVD 29)

Flood gage 

height 

(ft)1,2 Local flood impacts1
6 Estimated Flood-Inundation Mapping for the Lower Blue River in Kansas City, Missouri, 2003–05

#

#

#

#

#

U.S. Geological Survey

stage gage at

12th street 

U.S. Geological Survey

streamflow gage at Stadium Drive 

Kansas City, Missouri, 

ALERT gage at Blue Parkway 

Kansas City, Missouri, 

ALERT gage at 63rd Street 

National Weather Service

flood-forecast location 

at Highway 40

94°32' 94°30' 94°28'

39°00'

39°02'

39°04'

39°06'

39°08'

EXPLANATION

# GAGE OR FLOOD-FORECAST LOCATION

(ALERT, Automated Local Evaluation in Real Time)

LAND-SURFACE ELEVATION, 

 IN FEET ABOVE NATIONAL GEODETIC 

 VERTICAL DATUM OF 1929

 (Kansas City, Missouri, 2002, 2004)

960.1 to 970 

950.1 to 960 

940.1 to 950 

930.1 to 940 

920.1 to 930 

910.1 to 920 

900.1 to 910 

890.1 to 900 

880.1 to 890 

870.1 to 880 

860.1 to 870 

850.1 to 860 

840.1 to 850 

830.1 to 840 

820.1 to 830 

810.1 to 820 

800.1 to 810 

790.1 to 800 

780.1 to 790 

770.1 to 780 

760.1 to 770 

750.1 to 760 

740.1 to 750 

730.1 to 740 

720.1 to 730 

710.1 to 720 

709.2 to 710 

Figure 2. Land-surface elevation of the study area.

0 1

1

2 MILES

0 2 KILOMETERS

Base from U.S. Geological Survey digital data, 1:24,000, 1996

Universal Transverse Mercator projection, Zone 15

Horizontal coordinate information is referenced to the 

North American Datum of 1983 (NAD83)
Two-Dimensional Model Application 7

94°31'48" 94°31'28" 94°31'08"

39°00'55"

39°01'15"

39°01'35"

39°1'55"

Figure 3. Simulated study reach of the Blue River between 63rd Street and 

Blue Parkway.

0 500 FEET

0 300 METERS

Base from Jackson County Management Information Systems 

 digital data, 1:833, 2003

Universal Transverse Mercator projection, Zone 15

Horizontal coordinate information is referenced to the 

North American Datum of 1983 (NAD83)

Union Pacific Railroad 

60-foot triple barrel

concrete box culvert 

Lower Blue Parkway Bridge

Blue Parkway Bridge

Byram’s Ford 

historic site 

Blue River 

63rd Street 

Brighton Avenue

Hardesty Avenue

Unnamed

tributary

Unnamed tributary

Unnamed

tributary

Unnamed

tributary
8 Estimated Flood-Inundation Mapping for the Lower Blue River in Kansas City, Missouri, 2003–05

Hardesty Avenue

Union Pacific Railroad

63rd Street

Blue Parkway

0 1,000 2,000 FEET

0 300 600 METERS

Area of no flow

Sand and gravel channel

Thick brush and timber banks 

Thick timber corridor and thick underlying sprouts

Industrial area with kept grasses

Railroad embankment with ballast and sprouts

Impervious area with asphalt, concrete, and gravel

Residential area with kept grasses and interspersed trees

Thick grasses and scattered sprouts

Junkyard, cars, and machinery

Sand and gravel stockpile

Figure 4. Land-use coverage used in flow simulations in the study reach.

EXPLANATION

LAND USE—White areas within the study reach indicate buildings or other structures

94°32' 94°31'

39°00'

39°01'

Base from U.S. Geological Survey digital data, 1:24,000, 1996

Universal Transverse Mercator projection, Zone 15

Horizontal coordinate information is referenced to the 

North American Datum of 1983 (NAD83)

Lower Blue Parkway
Two-Dimensional Model Application 9

Incorporated, 19991) was used to construct and execute the twodimensional model. The SMS allows interactive editing and display of finite element networks in addition to tools specifically 

designed for FESWMS. 

Two-dimensional model geometry is characterized by elements and nodes in the form of a finite element network or mesh. 

The SMS software was used to convert existing 2-ft topographic 

contour data and supplemental field-survey data into a scatter 

data set that was optimally configured into a finite-element network, or mesh, consisting of triangular and quadrilateral elements. Field surveys were conducted using Global Positioning 

Systems (GPS) technology and conventional surveying techniques. First-floor elevations of commercial and residential structures and the Blue River channel bathymetry were surveyed. The 

finite-element mesh provides the geometric foundation for twodimensional flow characteristics as opposed to individual crosssections employed by one-dimensional models. 

The quality of the mesh was checked using a mesh-quality 

utility within SMS. Mesh quality refers to individual element 

shape and the consistency in which elements relate to one 

another; well-constructed elements will ensure better numerical 

stability in the finite element network. Elements should adhere 

to guidelines concerning interior angles, aspect ratios, element 

size, curved sides, and the location of midside nodes within the 

element. In addition to the shape of individual elements, guidelines are set to improve relative consistency among elements. 

Smooth contours and boundaries, adequate size transition 

among elements, density of elements, and the necessity of constructing smaller elements at the wet/dry boundary interface 

often were employed. The wet/dry interface is one of the more 

common causes of solution divergence, especially if the elements in transition are comparatively large, and only small parts 

of those elements actually are dry (Froehlich, 2002). The deeply 

incised channel within the study reach has steep banks that 

required smaller, thinner elements along the banks and additional element refinement near the top of the banks. 

Once a finite-element mesh has been created and the quality has been maintained, the elements of the mesh are characterized by assigning material (fig. 4) and hydraulic properties to 

the elements, such as Manning’s n roughness coefficients 

(Chow, 1959; Barnes, 1967; Arcement and Schneider, 1989), 

and additional turbulence parameters such as base kinematic 

eddy viscosities and element storativity depth. Manning’s n

roughness coefficients were established throughout the overbanks and within the channel banks. Roughness coefficients 

were water depth dependent and defined as the “lower depth” nvalue over an element existing less than the lower depth, and the 

“upper depth” n-value over an element existing greater than the 

upper depth; the n-value is interpolated linearly from the upper 

and lower n-values (Froehlich, 1989). Mannings n-roughness 

coefficients for the calibrated model run are listed in table 2.

Table 2. Manning’s n roughness coefficients for the calibrated model run.

[ft, feet]

Lower depth Upper depth

Land-use coverage Manning’s n Depth (ft) Manning’s n Depth (ft)

Channel and bank

Blue River main channel (sand and gravel) 0.040 3.0 0.025 4.0

Thick brush and timber banks .110 2.5 .080 5.0 

Thick timber corridor with thick sprouts .125 3.0 .092 6.0

Thick grasses and scattered sprouts .055 1.7 .040 3.2 

Flood plain

Industrial area with kept grasses 0.050 1.0 0.033 2.7 

Railroad embankment with ballast and sprouts .038 1.0 .032 2.0 

Impervious area with asphalt, concrete, and gravel .027 1.0 .025 2.0 

Residential area with kept grasses and interspersed trees .038 1.5 .032 2.5 

Commercial area with junkyard, cars, and machinery .150 5.0 .040 7.0 

Sand and gravel stockpile .032 1.0 .030 2.5 

1

Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
10 Estimated Flood-Inundation Mapping for the Lower Blue River in Kansas City, Missouri, 2003–05

Kinematic eddy viscosities (Vo ) represent turbulent conditions throughout the finite-element mesh and are necessary to 

provide numerical damping for model stability. Element storativity is another turbulence parameter that allows partially dry 

elements to be retained in calculations when solving governing 

equations (Froehlich, 2002). 

Piers for the existing Blue Parkway Bridge and the downstream adjacent lower Blue Parkway Bridge were incorporated 

into the mesh (fig. 5). A separate model was used to simulate 

proposed deck widening of the Blue Parkway Bridge and 

removal of the lower Blue Parkway Bridge. Piers for the proposed Blue Parkway Bridge also were incorporated into the 

mesh (fig. 6). The elements within each pier location were disabled to force flow around the piers. Dimensions of all piers 

were taken from bridge plans to accurately construct disabled 

elements. (Department of Public Works, City of Kansas City, 

2004).

Model Calibration 

The amount of flow into the mesh and a stage elevation 

where flow leaves the mesh are required model inputs. A flood 

occurred May 19, 2004, that produced both bank-full and 

overbank flow conditions. Peak-flow measurements and highwater marks were acquired during this event. The total flow 

along the study reach and stage elevation at the downstream 

face of the lower Blue Parkway Bridge were used as boundary 

conditions. Two bridges are present at the downstream end of 

the reach. The Blue Parkway Bridge over the Blue River, and 

the Union Pacific Railroad is approximately 50 ft upstream 

from the lower Blue Parkway Bridge (fig. 3). The downstream 

lower Blue Parkway Bridge consists of three, 54-ft concrete 

slab spans supported by two concrete main channel piers with 

solid web walls and vertical abutments. The main channel columns for the Blue Parkway Bridge were incorporated into the 

mesh along with the main channel piers for the lower Blue 

Parkway Bridge (fig. 5). The calibrated downstream stage elevation and the low-chord elevation (ceiling elevation) of both 

downstream bridges did not induce pressure flow. As a result, 

the low chord of both bridge decks was not acknowledged in 

the calibration model run. Elements representing vertical 

abutments at the downstream lower Blue Parkway Bridge 

were disabled to force encroachment of flow. 

Simulations cannot begin directly with boundary conditions that represent measured conditions. For sub-critical flow 

regimes, flow simulations often begin with the measured discharge and a flat stage-elevation slope. An iterative process 

known as “spindown” is required to gently lower the stage elevation at the downstream boundary condition. Subsequent 

iterative model runs are used as “hotstarts,” which provide the 

initial condition for the next model run. This process is 

repeated until the desired downstream stage elevation is 

achieved. Throughout the process of a “spindown,” elements 

often are manually disabled to prevent solution instability that 

comes from wetting and drying. Throughout the iterative process of a given simulation, nodes within elements may become 

dry if the stage elevation for that particular iteration is less 

than the land-surface elevation assigned to that node. Conversely, the element becomes wet if the stage elevation is 

greater than the assigned land-surface elevation for several 

element nodes. As the simulation proceeds through the 

assigned number of iterations, an element can oscillate 

between wet and dry (Huizinga and Rydlund, 2001), which 

can lead to solution instability but may sometimes be overcome by setting a storativity depth tolerance that defines the 

depth of flow over a node. However, if an element becomes 

dry and stays dry for several iterations, it should be disabled 

to allow model convergence (Huizinga and Rydlund, 2001). 

The peak stage of May 19, 2004, occurred at 6:30 p.m. at 

63rd Street. The main stem peak stage at the lower Blue Parkway Bridge, which was consistent with the peak stage at 63rd 

Street, occurred at 7:00 p.m. Discharge measurements were 

made in a boat using hydroacoustic technology at a location 

immediately upstream from the 63rd Street Bridge and at a 

location approximately 540 ft upstream from the mouth of 

Brush Creek (fig. 1). Both measurements were made at the 

time of the peak stage. The narrow and sinuous channel, timbered corridor, considerable velocities, standing waves, and 

turbulence prevented adequate hydroacoustic measurements 

to be made anywhere else in the study reach to obtain flow and 

velocity measurements. For the upstream and downstream 

locations, mean flows of 12,200 and 12,400 ft3/s (cubic feet 

per second) were computed. Both flows were averaged as 

12,300 ft3/s, which was considered the upstream total flow 

boundary condition for a steady-state condition. As a quality 

assurance measure, a current-meter measurement was made at 

the upstream face of the lower Blue Parkway Bridge concurrent with the hydroacoustic measurement at the location above 

the mouth of Brush Creek. The measured flow from the current-meter measurement was 12,900 ft3/s. 

Four distinct high-water marks indicating peak stage 

were identified along the study reach for the flood on May 19, 

2004. One mark, in a tributary approximately 1,700 ft 

upstream from the downstream face of lower Blue Parkway 

Bridge, was unusually high and was thought to represent a 

local peak before the Blue River peak of May 19, 2004, and 

was not included in the calibration process. The measured area 

and velocity of the current-meter measurement were used as 

calibration values at the downstream boundary condition. 

Although the hydroacoustic measurement was made immediately upstream from the downstream face of the 63rd Street 

Bridge (upstream boundary location), a comparison of simulated and measured velocity and cross-sectional area also
LOWER BLUE PARKWAY BRIDGE PIER EXPLANATION PIER

94°31'38" 94°31'36" 94°31'34" 94°31'32" 

39°02'01"39°02'03"39°02'05"

0 50 0 2 10 0 

Figure 5. Finite-element mesh incorporating pier configuration for the current (2005) Blue Parkway Bridge and downstream lower Blue Parkway Bflood of May 19, 2004.

Lower Blue Parkway Bridge 

Blue Parkway Bridge

Union Pacific 

Railroad

Base from Jackson County Management Information Systems  digital data, 1:833, 2003Universal Transverse Mercator projection, Zone 15Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD83)
94°31'38" 94°31'36" 94°31'34" 94°31'32" 

39°02'03" 39°02'05"

Figure 6. Modified finite-element mesh based on pier configuration of the proposed Blue Parkway structure.

Blue Parkway Bridge

0 50 0 10 20 

PROPOSED PIER PLACEMENT

EXPLANATION

Lower Blue Parkway Bridge 

Union Pacific 

Railroad

Base from Jackson County Management Information Systems  digital data, 1:833, 2003Universal Transverse Mercator projection, Zone 15Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD83)
Two-Dimensional Model Application 13

was made at the upstream model boundary. Measured and simulated stage elevation, cross-sectional area, and velocity are 

described in table 3. Generally, the measured stage elevations 

were within 0.2 to 0.53 ft of the simulated stage elevations. The 

quality of the high-water marks indicating measured stage elevation was considered poor. 

Table 3. Measured and simulated stage elevation, cross-sectional area, and velocity.

[ft, feet; ft2, square feet; ft/s, feet per second; --, not determined/not applicable]

Location

Measured 

stage 

elevation 

(ft)

Simulated 

stage 

elevation 

(ft)

Measured 

crosssectional area 

(ft2

)

Simulated 

crosssectional area 

(ft2

)

Measured 

velocity 

(ft/s)

Simulated 

velocity 

(ft/s)

Lower Blue Parkway Bridge 748.591

1

Starting stage elevation boundary condition. 

748.591 1,883 1,797 6.85 6.87 

Brighton Ave. toe of embankment 756.56 756.78 -- -- -- -- 

Byram’s Ford 760.32 760.85 -- -- -- -- 

63rd Street Bridge 762.39 762.80 4,2302

2Measurement made immediately upstream from 63rd Street Bridge. Simulated results obtained from downstream face of bridge. 

4,8412 2.882 2.542

Except for a flood-plain area in the middle of the study 

reach, the flood of May 19, 2004, primarily was contained 

within the channel and overbanks. Velocities as high as 12 ft/s 

(feet per second) were simulated at the downstream end of the 

study reach because of increased slope, a narrow confined section of channel, and converging flow from the lower Blue Parkway Bridge (figs. 3, 7). The increased slope likely is caused by 

the channelization immediately downstream, which has lowered the stage elevation at the downstream end of the unchannelized reach and thus increased the water-surface slope. The 

general stage-elevation slope throughout the reach for the calibrated flood was approximately 0.0013 ft/ft (foot per foot) or 

about 7 ft/mi (feet per mile). Water depths of 25 to 30 ft were 

simulated in the deeply incised channel (fig. 8). The stage elevation depicted the greatest changes where substantial water 

velocity gradients occurred (fig. 9). 

Development of Simulated Rating Using OneDimensional Hydraulic Analysis 

To produce flood-inundation layers for the study reach, a 

range of boundary conditions was developed for high flows. 

This was accomplished using existing one-dimensional Hydraulic Engineering Centers River Analysis System (HEC-RAS) 

model results from the USACE on the lower Blue River main 

stem (hereinafter referred to as the “lower Blue River HEC-RAS 

model”). Results were available from this model for a range of 

discharges on the improved channel from the mouth of the Blue 

River to a cross section immediately upstream from the mouth of 

Brush Creek (fig. 1). A new HEC-RAS model (hereinafter 

referred to as the “constructed HEC-RAS model”) was constructed to extend the results from the lower Blue River HECRAS model from immediately upstream from the mouth of 

Brush Creek to the upstream face of the lower Blue Parkway 

Bridge. Cross sections were derived from the available 2-ft contour data and cross-section data acquired from discharge measurements. Five cross sections were used in the constructed 

HEC-RAS model (fig. 10). Input into the constructed HEC-RAS 

model consisted of stage elevation and discharge measurements 

made at the upstream side of the lower Blue Parkway Bridge 

(cross-section 4) and at the limit of channel improvement immediately upstream from the mouth of Brush Creek (cross-section 

1) for the May 19, 2004, flood. The constructed HEC-RAS 

model was calibrated to the discharge measurements (table 4).

Table 4. Measured and simulated conditions for the constructed HEC-RAS model.

[ft, feet; ft2, square feet; ft/s, feet per second

Cross-section 1 Cross-section 4

Hydraulic parameter Measured Simulated Measured Simulated

Stage Elevation (ft) 747.4 747.4 749.16 749.16 

Flow area (ft2) 2,901.8 2,909.5 1,883.00 1,888.40 

Top width (ft) 238.2 238.4 146.00 145.30 

Velocity (ft/s) 4.3 4.34 6.85 6.60 
14 Estimated Flood-Inundation Mapping for the Lower Blue River in Kansas City, Missouri, 2003–05

FIgure 7. Simulated velocity magnitude for the May 19, 2004, flood. 

94°31'48" 94°31'28" 94°31'08"

39°00'55"

39°01'15"

39°01'35"

39°01'55"

0 500 FEET

0 300 METERS

12

0

9

6

3

VELOCITY, IN FEET 

 PER SECOND

EXPLANATION

63rd Street 

Blue Parkway 

Union Pacific Railroad 

Brighton Avenue

Hardesty Avenue

Unnamed

tributary

Unnamed tributary

Unnamed

tributary

Unnamed

tributary

Base from Jackson County Management Information Systems 

 digital data, 1:833, 2003

Universal Transverse Mercator projection, Zone 15

Horizontal coordinate information is referenced to the North

American Datum of 1983 (NAD83)
Two-Dimensional Model Application 15

94°31'48" 94°31'28" 94°31'08"

39°00'55"

39°01'15"

39°01'35"

39°01'55"

Figure 8. Simulated water depth for the May 19, 2004, flood. 

EXPLANATION

0 500 FEET

0 300 METERS

30

0

21

15

6

27

24

18

12

9

3

WATER DEPTH, IN FEET

63rd Street 

Blue Parkway 

Union Pacific Railroad 

Brighton Avenue

Hardesty Avenue

Unnamed

tributary

Unnamed tributary

Unnamed

tributary

Unnamed

tributary

Base from Jackson County Management Information Systems 

 digital data, 1:833, 2003

Universal Transverse Mercator projection, Zone 15

Horizontal coordinate information is referenced to the 

North American Datum of 1983 (NAD83)
16 Estimated Flood-Inundation Mapping for the Lower Blue River in Kansas City, Missouri, 2003–05

Measured stage

756.56 feet 

Simulated stage

756.78 feet 

Observed stage

760.32 feet 

Simulated stage

760.85 feet 

Observed stage

762.39 feet 

Simulated stage

762.80 feet 

Observed stage

748.59 feet 

763.2

748.5

758.8

755.9

751.4

761.7

760.3

757.3

754.4

752.9

750.0

STAGE ELEVATION, 

 IN FEET ABOVE THE NATIONAL

 GEODETIC VERTICAL DATUM 

 OF 1929

EXPLANATION

HIGH-WATER OBSERVATION

Figure 9. Simulated stage elevation and high-water observations for

the May 19, 2004, flood. 

0 500 FEET

0 300 METERS

94°31'48" 94°31'28" 94°31'08"

39°00'55"

39°01'15"

39°01'35"

39°01'55"

63rd Street 

Blue Parkway 

Union Pacific Railroad 

Brighton Avenue

Hardesty Avenue

Unnamed

tributary

Unnamed tributary

Unnamed

tributary

Unnamed

tributary

Base from Jackson County Management Information Systems 

 digital data, 1:833, 2003

Universal Transverse Mercator projection, Zone 15

Horizontal coordinate information is referenced to the North

American Datum of 1983 (NAD83)
Two-Dimensional Model Application 17

94°31'47" 94°31'37" 94°31'27" 94°31'17" 94°31'07"

0 100 200 300 METERS 

0 300 600 FEET 

39°02'02"

39°02'12"

39°02'22"

Figure 10. Cross sections used in the constructed Hydraulic Engineering Centers River Analysis System (HEC-RAS) model.

EXPLANATION

CROSS SECTION 1—U.S. Army Corps of Engineers cross section 

CROSS SECTION 2—Approximate limit of channel improvement 

CROSS SECTION 3—U.S. Army Corps of Engineers cross section

 combined with modified channel section 

CROSS SECTION 4—Upstream face measurement location lower Blue

 Parkway Bridge

CROSS SECTION 5—Proposed modification of the Blue Parkway Bridge section 

Blue Parkway 

Brighton Avenue 

Hardesty Avenue 

Union Pacific Railroad 

Brush Creek

Blue

River

Unnamed

tributary

Base from Jackson County Management Information Systems 

 digital data, 1:833, 2003

Universal Transverse Mercator projection, Zone 15

Horizontal coordinate information is referenced to the North

American Datum of 1983 (NAD83)

1

2

3

5 4
18 Estimated Flood-Inundation Mapping for the Lower Blue River in Kansas City, Missouri, 2003–05

Differences as much as 0.5 ft in stage elevation were 

observed between the lower Blue River HEC-RAS model and 

the constructed HEC-RAS model when calibrated for the discharge from the May 19 measurement data. Stage elevation differences likely were a result of scour and fill process that may 

have occurred as a result of lower main stem channel improvements. Because the Blue River is in a sub-critical flow regime 

where one-dimensional standard step computations are appropriate, the two HEC-RAS models would represent parallel slope 

or energy-grade line (EGL) characteristics at the upstream end 

of the lower Blue River HEC-RAS model and downstream end 

of the constructed HEC-RAS model. The difference in the EGL 

for the two models was 0.00003 ft/ft. This difference in EGL 

was maintained for the 2- to 500-year discharges provided by 

the lower Blue River HEC-RAS model, and are listed in table 5.

Table 5. Energy-grade line (EGL) slope for the Kansas City U.S. Army Corps of Engineers HEC-RAS model of the lower Blue River and HECRAS model constructed between the lower Blue River model and the study reach for selected flood-frequency values. 

[ft3/s, cubic feet per second; EGL, energy-grade line; ft/ft, foot per foot]

Flood 

frequency 

(years)

Discharge

(ft3)

EGL slope at cross-section 1 of the 

lower Blue River HCE-RAS model

(ft/ft)

EGL slope at cross-section 1 of the 

constructed HCE-RAS model

(ft/ft)

2 13,200 0.000574 0.000544 

5 20,300 .000512 .000482 

10 26,320 .000454 .000424 

20 34,000 .000382 .000352 

50 44,500 .000338 .000308 

100 53,690 .000344 .000314 

200 62,000 .000336 .000306 

500 74,720 .000366 .000336 

Eight flood-frequency discharge values acquired from the 

Kansas City USACE were modeled from cross-section 1 

upstream using the EGL from table 5 to the face of the lower 

Blue Parkway Bridge where the study reach begins (USACE, 

written commun., 2004). The simulated stage elevation for each 

of the flood-frequency discharge values was used to develop a 

stage-discharge rating at the face of the lower Blue Parkway 

Bridge. The resulting rating provided the boundary condition 

information needed to use the two-dimensional simulation to 

create flood-inundation maps from the lower Blue Parkway 

Bridge to 63rd Street. Discharge values associated with stage 

elevation at the lower Blue Parkway Bridge at 2-ft increments 

from 750 through 772 ft were selected from the rating curve and 

input into the two-dimensional model (table 6). 

Simulated Velocity Magnitude and Direction FloodInundation Maps 

The hydraulic flood-inundation model for the study reach 

incorporates design plans for the proposed Blue Parkway structure over the Blue River and Union Pacific Railroad. New pier 

alignment and pier dimensions were coded into the finite element mesh (fig. 6) and another “spindown” process was initiated beginning with the first boundary conditions at a discharge 

of 71,690 ft3

/s and stage elevation at 772 ft. Once the model 

attained acceptable convergence parameters, the next floodstage elevation was simulated. Convergence parameters, 

including an average change in unit flow rates in the x and y 

direction and an average change in stage elevation, were examined for each simulated flood-stage elevation. Acceptable convergence was achieved with an average change in unit flow 

rates of less than 0.1 ft2

/s (square foot per second) and an average change in stage elevation less than 0.1 ft. Geographic information system (GIS) technology was used to create velocity 

magnitude and direction profiles for the study reach. Twelve 

flood-stage elevations (2-ft increments for 750 to 772 ft above 

NGVD29) are depicted for the downstream vicinity of 63rd 

Street, the middle of the study reach, and the upstream vicinity 

of the lower Blue Parkway Bridge in Appendixes 1, 2, and 3 (at 

the back of this report). 

Estimated Flood-Inundation Mapping

Flood-profile slopes of the Blue River between Gregory 

Boulevard and 63rd Street were developed from stage elevations calculated from high-water marks from the flood of May 

19, 2004. Locations of visible changes in flood-stage elevation 

slopes were identified and different stage-elevation slopes were 

used between each break in slope. To ensure the consistency of 
Estimated Flood-Inundation Mapping 19

Blue River flood-stage elevation in this reach, the stage elevation at each change in slope was determined from downstream 

to upstream with the two-dimensional model-derived stage elevations at 63rd Street as the starting point. 

Table 6. Simulated rating depicting stage elevation at the lower 

Blue Parkway Bridge and discharge as boundary conditions for 

developed flood-inundation maps in the study reach.

[ft, feet; ft3/s, cubic feet per second

Stage 

elevation 

(ft)

Discharge

(ft3

/s)

750 13,930 

752 16,740 

754 20,110 

756 23,210 

758 26,650 

760 29,970 

762 33,700 

764 37,630 

766 41,920 

768 48,100 

770 56,670 

772 71,690 

Stage elevation between 63rd Street and Blue Parkway 

was determined using the two-dimensional flow-modeling 

results previously described. The stage discharge relation 

developed between the two-dimensional model and the Lower 

Blue River HEC-RAS model for the constructed HEC-RAS 

model was used to calculate stage and stage-elevation slopes for 

the reach of unimproved channel between Blue Parkway and 

the upstream limit of the improved channel (fig.1). Stage-elevation slopes and stage elevations between the upstream limit of 

the improved channel and the mouth of the Blue River were 

obtained from the lower Blue River HEC-RAS model results 

(fig. 11). The lower Blue River HEC-RAS model is based on 

theoretical flow in the improved Blue River channel and was 

not calibrated to actual flow events; however, because stagedischarge measurements during floods on the lower Blue River 

were unavailable for improved channel conditions, the model 

results represent the best available data for that reach. Locations 

of visible changes in flood-stage elevation slope in this reach 

were identified, and different stage-elevation slopes were used 

between each break in slope. To ensure the consistency of the 

entire Blue River flood-stage elevation, the stage-elevation 

slopes were used between each break in slope. The relation 

between stage at Blue Parkway and the upstream limit of the 

improved channel developed for the constructed HEC-RAS 

model was used to ensure consistency between the two-dimensional model results and the Lower Blue River HEC-RAS 

model results. The lower Blue River HEC-RAS model provided 

river profiles and stage elevations for the 2-, 5-, 10-, 20-, 50-, 

100-, 200-, and 500-year floods at each change in slope. The 

range of stage elevations of the model encompass the range of 

stage elevations selected for flood-inundation mapping, but do 

not correspond exactly. To select the appropriate flood-stage 

slope from the model results, the stage elevation for the floodinundation surface was compared to the stage elevation determined by the model. The appropriate flood-stage slope chosen 

was from the profile with the stage elevation closest to the 

desired flood inundation stage elevation. 

Missouri River backwater inundation profiles from flood 

stage to the highest stage recorded in July 1993 were developed 

by interpolating the Missouri River stage elevation recorded at 

the gage at Kansas City to the mouth of the Blue River using 

slopes derived from Kelly (1996) and Perry and others (1997). 

The calculated stage elevation profiles and source of slope data 

(lower Blue River HEC-RAS model, calibrated two-dimensional model, or high-water marks) from Gregory Boulevard to 

the mouth of the Blue River for all Blue River flood-inundation 

maps are shown on figure 11. 

The Kansas City Missouri ALERT Gage at Blue Parkway 

was chosen as the reference gage for the Blue River flood-inundation mapping to provide a consistent naming convention 

between flood maps and two-dimensional model results. A Blue 

River NWS flood-stage elevation of 750 ft (NGVD 29) at Blue 

Parkway was used as the base elevation to generate all of the 

flood-inundation maps. Twelve maps were produced at 2-ft 

intervals from stage elevations from 750 to 772 ft at Blue Parkway to approximate the range of river stages from the 2- to 500-

year flood frequencies (tables 5 and 6). Stage elevations and 

gage heights for floods at forecast locations within the study 

area for flooding on the Blue River are listed in table 7.

Upstream from 63rd Street and downstream from Blue 

Parkway, stage elevations at each forecast location and breaks 

in slope were extrapolated across the flood plain along cross 

section lines oriented perpendicular to the downstream direction of the Blue River flood plain. The locations of these cross 

sections and the study reach, which required no horizontal 

extrapolation, are shown on figure 12. 

Two-dimensional model results, boundaries of the study 

area and study reach, cross sections of equal flood-stage elevation at gages, and changes in flood profile slopes were input into 

the GIS software program ARC/INFO. ARC/INFO software 

was used to interpolate flood-stage elevations between cross 

sections for each flood profile to produce sloped flood-inundation surfaces. The resulting surface was converted to a raster 

data set representing the flood-inundation surface using square 

cells, 5 ft on a side. 
720 730 740 750 760 770 780 790 800 0 24 6 810 12 14 16 

12th Street Stadium Drive Blue Parkway 63rd Street Gregory Boulevard Mouth 40 Highway 

1413 

22 20 19 17 18 16 15 13 14 12 9 10 11 7 8 5 6 4 3 2 1 21 23

STAGE ELEVATION, IN FEET ABOVE NGVD 29

RIVER MILE

Figure 11. Calculated Blue River slopes, stage elevations, cross sections, and sources of data for all flood-inundation maps from Gregory Boulevard to the mouth of the Blue River.

Data from the lower Blue River 

Hydraulic Engineering Centers-River Analysis System (HEC-RAS) model, 

U.S. Army Corps of Engineers, 2004

Data from 

calibrated model,

U.S. Geological 

Survey

Data from

high-water marks,

U.S. Geological 

Survey,

May 19, 2004
Estimated Flood-Inundation Mapping 21

1 2

3 4

5

6 7

8

9

22

#

#

#

#

#

# U.S. Geological Survey

stage gage at

12th street 

U.S. Geological Survey streamflow

gage at Stadium Drive 

Kansas City, Missouri, 

ALERT gage at Blue Parkway 

Kansas City, Missouri, 

ALERT gage at 63rd Street 

94°32' 94°30' 94°28'

39°00'

39°02'

39°04'

39°06'

39°08'

EXPLANATION

Figure 12. Location of cross sections used for flood-inundation area interpolation 

and the area of the constructed FESWMS used to create flood-inundation surfaces.

10

11

12

13

14

15

16

17

18

23

20

21

3

0 1

1

2 MILES 

0 2 KILOMETERS 

FINITE-ELEMENT SURFACE-WATER 

 MODELING SYSTEM (FESWMS) AREA

SECTION AND NUMBER

FLOOD-FORECAST LOCATION

(ALERT, Automated Local Evaluation in Real Time)

National Weather Service

flood-forecast location

at Highway 40

19

Base from Jackson County Management Information Systems 

 digital data, 1:833, 2003

Universal Transverse Mercator projection, Zone 15

Horizontal coordinate information is referenced to the North

American Datum of 1983 (NAD83)
Table 7. Equivalent peak flood-stage elevations and gage heights for forecast locations for flood inundation on the Blue River.

[ft, feet; datum NGVD29; bold stage elevation indicates gage height is above flood stage] 

Forecast location

12th Street U.S. Highway 40 Stadium Drive Blue Parkway 63rd Street

Stage 

elevation

(ft)

Gage 

height (ft 

above 

gage 

datum of 

714.41)

Stage 

elevation

(ft)

Gage 

height (ft 

above 

gage 

datum of 

721.65)

Stage 

elevation

(ft)

Gage 

height (ft 

above 

gage 

datum of 

718.30)

Stage 

elevation

(ft)

Gage 

height (ft 

above 

gage 

datum of 

722.47)

Stage 

elevation

(ft)

Gage 

height (ft 

above 

gage 

datum of 

721.78)

736.3 21.9 739.5 17.8 741.1 22.8 750.0 27.5 763.8 42.0 

737.9 23.5 741.1 19.4 742.7 24.4 752.0 29.5 765.8 44.0

740.1 25.7 743.3 21.7 744.8 26.5 754.0 31.5 767.8 46.0

741.7 27.3 744.9 23.3 746.4 28.1 756.0 33.5 769.8 48.0

744.0 29.5 747.1 25.5 748.5 30.2 758.0 35.5 771.8 50.0

745.8 31.3 748.9 27.3 750.3 32.0 760.0 37.5 773.8 52.0

747.7 33.3 751.7 30.1 752.8 34.5 762.0 39.5 775.8 54.0

749.6 35.2 753.6 32.0 754.7 36.4 764.0 41.5 777.8 56.0

751.6 37.2 754.9 33.3 757.0 38.7 766.0 43.5 779.8 58.0

754.1 39.7 757.4 35.8 759.5 41.2 768.0 45.5 781.8 60.0

756.0 41.6 759.0 37.4 761.0 42.7 770.0 47.5 783.8 62.0

758.3 43.9 761.6 39.9 762.9 44.6 772.0 49.5 785.8 64.0

22 Estimated Flood-Inundation Mapping for the Lower Blue River in Kansas City, Missouri, 2003–05

Land-surface elevations from 2001 with updates from 

2004, provided by the city of Kansas City, Missouri, included 

the latest modifications to the Blue River channel and were converted to a raster data set representing land surface using square 

cells, 5 ft on a side. Elevations of all bridges that span the Blue 

River and major roadways on the flood plain of the Blue River 

were incorporated into the land-surface elevation data. The data 

generally are accurate to 1 ft (one-half of the 2-ft contour interval). Flood-inundation maps were created by subtracting the 

land-surface elevation from the flood-stage elevation for each 

flood-inundation surface. The positive values in the resulting 

raster data set indicate the extent of flood inundation and the 

water depth. The resolution of each flood inundation raster data 

set is the same as the flood-inundation surface and the land surface. 

Some locations within the study area are protected by 

levees, flood walls, or embankments. The techniques used to 

generate the flood-inundation maps identified these protected 

areas as being inundated although they are protected from 

flooding as long as Blue River stage elevation is below the top 

of the levee or flood wall. A field survey was conducted to 

determine if these locations were open to flooding from the 

Blue River at stage elevations below the tops of the levee, flood 

wall, or embankment protecting the site. Sites were inspected 

for culverts, pipes, or other openings that would allow water to 

enter the protected area. Protected sites are indicated on the 

flood-inundation maps as areas that lie lower than the selected 

flood-stage elevation of the inundation map. Unprotected sites 

are indicated as inundated. Twelve Blue River flood-inundation 

maps are shown on plates 4.1 through 4.12 in Appendix 4 (at the 

back of this report). 

The Blue River flood-inundation surfaces used for maps in 

this report (appendix 4) correspond to hypothetical surfaces 

demarked by the maximum inundation of the flood plain. Consequently, these maps do not depict stage elevations that occur 

at a point in time, but a surface of inundation caused by a flood 

peak that occurs at different locations at different times. Also, 

the flood-inundation maps are based on uniform increments of 

river stage elevation above flood-stage elevation and not on discharge changes. Therefore, it is unlikely that one map will correctly represent flood inundation for the entire study area 

caused by a single flood. Rather, flood inundation will be represented for different forecast locations using inundation maps 

that match the peak river stage elevation for each forecast location. 
Estimated Flood-Inundation Mapping 23

94°32' 94°30' 94°28'

39°00'

39°02'

39°04'

39°06'

39°08'

A B C D E F

13

12

11 

10

9

8

7

6

5

4

3

2

1

EXPLANATION

*# GAGE OR FLOOD-FORECAST LOCATION

(ALERT, Automated Local Evaluation in Real Time)

FORECAST LOCATION REGION

12th Street 

12th Street or Highway 40 

Highway 40 or Stadium Drive 

Stadium Drive 

Blue Parkway or Stadium Drive 

Blue Parkway 

63rd Street 

Figure 13. Regions and sections of the Blue River flood-inundation maps associated 

with each forecast location.

0 1

1

2 MILES 

0 2 KILOMETERS 

Base from Jackson County Management Information Systems 

 digital data, 1:833, 2003

Universal Transverse Mercator projection, Zone 15

Horizontal coordinate information is referenced to the North

American Datum of 1983 (NAD83)

*#

*#

*#

*#

*#

U.S. Geological Survey

stage gage at

12th street 

Kansas City, Missouri, 

ALERT gage at 63rd Street 

National Weather Service

flood-forecast location 

at Highway 40

Kansas City, Missouri, 

ALERT gage at Blue Parkway 

U.S. Geological Survey streamflow

gage at Stadium Drive 
24 Estimated Flood-Inundation Mapping for the Lower Blue River in Kansas City, Missouri, 2003–05

The study area was divided into five regions that correspond to the five forecast locations on the Blue River (fig. 13). 

Each region is divided into equal-sized square sections (4,000 ft 

on a side) that correspond to the square sections shown on 

flood-inundation plates in appendix 4. Several sections are 

associated with two forecast location regions because the extent 

of flood inundation for those sections is equally valid for data 

from either forecast location. Sections are named by their 

respective row (1-13) and column (A-F) designations. For 

example, section 1-C is at the top center of each plate and section 13-A is at the bottom left of each plate. 

The USGS streamflow gage on the Missouri River at Kansas City, Missouri, was chosen as the reference gage for maps 

of Blue River inundation caused by backwater from floods on 

the Missouri River. Backwater-inundation maps of the Blue 

River were developed using techniques similar to those used to 

create the Blue River flood-inundation maps. River-stage elevation data for the flood of 1993, the 500-year flood, the 100-year 

flood, and lower flood data were used to determine the change 

in stage elevation between the USGS streamflow gage and the 

mouth of the Blue River (Kelly, 1996, Perry and others, 1997). 

At stage elevations above flood-stage elevation on the Missouri 

River, the decrease in river-stage elevation between the USGS 

streamflow gage on the Missouri River at Kansas City and the 

mouth of the Blue River becomes greater as river stage rises. 

This occurs because levees and flood walls between the USGS 

gage and the mouth of the Blue River are nearer to the channel 

of the Missouri River than upstream and downstream from this 

reach, and flow is constricted in the Missouri River during 

floods. At the mouth of the Blue River, a Missouri River stage 

elevation of 730.9 ft was used as the lowest elevation for generation of backwater-inundation maps. This stage elevation corresponds to an elevation of 738.4 ft and a NWS flood stage of 32 

ft at the USGS streamflow gage on the Missouri River at Kansas 

City. Twelve maps were produced at 2-ft intervals from 730.9 

to 752.9 ft (Missouri River stage at the USGS streamflow gage 

from 32 to 59.3 ft) to include the historic range of Missouri 

River stage elevations above flood-stage elevation for the Kansas City area. Equivalent stage elevations and gage heights for 

forecast locations within the study area for Missouri River 

backwater inundation of the Blue River are listed in table 8.

Table 8. Equivalent flood-stage elevations and gage heights for forecast locations for Missouri River backwater inundation of the Blue 

River.

[ft, feet; datum NGVD29; bold stage elevation indicates gage height is above flood stage; na, not applicable]

Forecast location

Missouri River at Kansas City Blue River at the mouth 12th Street U.S. Highway 40

Stage 

elevation 

(ft)

Gage height 

(ft above gage 

datum of 

706.4)

Stage 

elevation 

(ft) Gage height 

Stage 

elevation 

(ft)

Gage height 

(ft above gage 

datum of 

714.41)

Stage 

elevation 

(ft)

Gage height 

(ft above gage 

datum of 

721.65)

738.4 32.0 730.9 -- 730.9 16.5 730.9 9.3 

740.9 34.5 732.9 -- 732.9 18.5 732.9 11.3 

743.8 37.4 734.9 -- 734.9 20.5 734.9 13.3 

745.8 39.4 736.9 -- 736.9 22.5 736.9 15.3 

749.0 42.6 738.9 -- 738.9 24.5 738.9 17.3 

752.5 46.1 740.9 -- 740.9 26.5 740.9 19.3 

755.3 48.9 742.9 -- 742.9 28.5 742.9 21.3 

757.7 51.3 744.9 -- 744.9 30.5 744.9 23.3 

759.7 53.3 746.9 -- 746.9 32.5 746.9 25.3 

761.7 55.3 748.9 -- 748.9 34.5 748.9 27.3 

763.7 57.3 750.9 -- 750.9 36.5 750.9 29.3 

765.7 59.3 752.9 -- 752.9 38.5 752.9 31.3
Table 8. Equivalent flood-stage elevations and gage heights for forecast locations for Missouri River backwater inundation of the Blue 

River.—Continued

[ft, feet; datum NGVD29; bold stage elevation indicates gage height is above flood stage; na, not applicable]

Forecast location

Stadium Drive Blue Parkway 63rd Street

Stage 

elevation 

(ft)

Gage height 

(ft above gage 

datum of 

718.30)

Stage 

elevation 

(ft)

Gage height 

(ft above gage 

datum of 

722.47)

Stage 

elevation 

(ft)

Gage height 

(ft above gage 

datum of 

721.78)

730.9 12.6 730.9 8.4 730.9 9.1

732.9 14.6 732.9 10.4 732.9 11.1

734.9 16.6 734.9 12.4 734.9 13.1

736.9 18.6 736.9 14.4 736.9 15.1

738.9 20.6 738.9 16.4 738.9 17.1

740.9 22.6 740.9 18.4 740.9 19.1

742.9 24.6 742.9 20.4 742.9 21.1

744.9 26.6 744.9 22.4 744.9 23.1

746.9 28.6 746.9 24.4 746.9 25.1

748.9 30.6 748.9 26.4 748.9 27.1

750.9 32.6 750.9 28.4 750.9 29.1

752.9 34.6 752.9 30.4 752.9 31.1

Estimated Flood-Inundation Mapping 25

The elevation of the backwater inundation surface as calculated is constant and equal to the stage elevation at the mouth 

of the Blue River. Therefore, backwater-inundation-surface 

profiles are flat. Backwater-inundation-stage elevations were 

created in ARC/INFO by assigning the stage elevation at the 

mouth of the Blue River to all cells in each raster data set. Backwater-inundation maps were created by subtracting the landsurface elevation data from the backwater-inundation-stage elevation data. The positive values in the resulting raster data set 

indicate the extent of backwater inundation and the water depth. 

The resolution of each backwater-inundation raster data set (5-

ft squares) is the same as the backwater-inundation surface and 

the land-surface elevation. Areas protected by levees were identified as previously discussed, and are indicated as areas that lie 

lower than the selected flood stage elevation of the inundation 

map. Twelve Blue River backwater-inundation maps are shown 

in appendix 5 (plates 5.1 through 5.12, at the back of this 

report). Backwater-inundation maps are divided into the same 

sections as the flood-inundation maps. However, stage elevation data from the USGS streamflow gage on the Missouri River 

at Kansas City are associated with all sections because it was 

the only gage used to create the backwater-inundation maps.

Estimated Flood-Inundation Mapping Benefits and 

Limitations 

The estimated flood-inundation maps created during this 

study are an important tool for public officials and residents to 

use to minimize flood deaths and damage in the flood plain of 

the lower Blue River in Kansas City, and to supplement information collected by the metropolitan Kansas City flood-alert 

system. Availability on the World Wide Web of estimated 

flood-inundation maps and near real-time river-stage data permit users to view near real-time stage information and select 

inundation maps for current flood conditions, forecasted peak 

stage, or other selected crests. Forecast inundation maps permit 

people in flood-affected areas to know where unsafe driving 

conditions are or might be, and to warn neighbors who do not 

have computer access or the World Wide Web. Local emergency management personnel can use forecast peak inundation 

maps to determine threatened areas, identify road closures, and 

take appropriate actions to warn property owners. The maps 

will help the public, business owners, and the media give warnings of property and roads threatened by floodwater, help in rescue operations during a flood, and may help save lives. Federal, 

State, and local emergency management teams can more effi-
26 Estimated Flood-Inundation Mapping for the Lower Blue River in Kansas City, Missouri, 2003–05

ciently conduct damage assessments and provide public information concerning flood insurance, acquisition of property, and 

applications for hazard mitigation grants (Studley, 2003). 

In addition to providing information related to the location 

and the water depth of inundated areas, the two-dimensional 

modeling results also provide velocity magnitude and direction 

throughout the study reach along the Blue River between 63rd 

Street and Blue Parkway. Such hydraulic details can be used for 

proposed channel improvements and assessing flooding effects 

on structures in the flood plain. 

Although there are substantial benefits to the flood-inundation maps, correct map interpretation depends on understanding the limitations and the error associated with the data used to 

construct the maps. Data used to construct the flood-inundation 

maps include topographic data, one- and two-dimensional 

hydraulic model results, measured high-water marks, and interpolated stage elevations. In addition, small tributary flooding 

and ponding of local runoff can cause inundation not depicted 

on the maps. 

Flood-inundation maps show inundation for the downstream reaches of some minor tributaries of the Blue River. 

Flood inundation indicated for these tributaries is from flooding 

on the Blue River. When flooding occurs on these tributaries, as 

well as on the Blue River, the actual flood inundation along 

these tributaries could be higher than the estimated flood inundation. Inundation maps in this report also assume open channels with no blockages from log jams or other debris. Flood 

inundation can be greater upstream from the obstructions.

Topographic data provided by the city of Kansas City is 

accurate to plus or minus 1 ft (one-half the contour interval of 2 

ft). Depth of flood inundation was calculated by subtracting 

land-surface elevation from stage elevation for each flood-inundation map. For areas that are flat or have a low slope, a 1-ft 

increase or decrease in flood depth may result in a large increase 

or decrease in inundated area. 

Hydraulic models are approximations of actual streamflow 

and simulated discharge and stage typically deviate from reality. Measurements of discharge typically are within plus or 

minus 5 percent of the actual discharge, and hydraulic model 

results calibrated to measured discharge are subject to the limitations of those measurements. Variations in the error range are 

caused by changes in the cross-sectional area of flow at different discharge values. As stated in the model calibration section, 

the two-dimensional model results were within about 0.5 ft of 

high water marks for the study reach. However, error also is 

associated with the use of high-water marks collected after a 

flood. These marks are indicated by the elevation of the line of 

sediment or mud-coated surfaces or the location of deposits of 

floating material that were left behind as flood water receded. 

They approximate the maximum elevation of the flood surface, 

but are not exact because of wave action, multiple peaks, or 

peaks from local tributaries; errors usually are less than 0.25 ft.

During flood conditions when water flows at a high velocity, ramping may occur as water flows over submerged structures. This can raise the flood surface above what an interpolated surface indicates over small areas near submerged 

structures. Ramping can occur where water flows over submerged road beds, bridge decks, or other large features. In areas 

where flow is constricted, such as bridges or other structures 

with small openings, actual stage elevations may differ from 

interpolated stage elevations over small areas near the constriction. Upstream from these structures, the actual stage elevation 

will be higher than the interpolated surface; downstream the 

stage elevation will be lower. The amount of error is variable 

and depends on water velocity and the size of the constriction.

Flooding usually is associated with large amounts of local 

rainfall. Inundation from direct rainfall of some small areas 

within the Blue River flood plain may occur from small tributaries before the flood-inundation maps indicate flooding 

caused by the Blue River. 

Errors and variations in data rarely occur in only one direction. The chance that the flood-inundation data for any one 

point is based on the maximum possible error is small because 

the errors are unlikely to be all positive or all negative with 

respect to the actual value. A combination of errors of varying 

value and sign is more likely to occur. To account for errors, the 

user should inspect not only the maps that represent the gage 

location and stage of interest, but also maps for values of stage 

both greater and less than the stage of interest. 

Blue River Estimated Flood-Inundation Maps on the 

World Wide Web 

To provide public access to the information presented in 

this report, a World Wide Web site (http://mo.water.usgs.gov/

indep/kelly/blueriver/index.htm) was created that displays the 

results of two-dimensional modeling between 63rd Street and

Blue Parkway, flood-inundation maps, backwater-inundation 

maps, and the latest gage heights and NWS stage forecast for

each forecast location within the study area. In addition, the full 

text of this report, tables, and plates are available for download. 

The Web site URL is http://pubs.water.usgs.gov/sir2006-5089/.

The main page of the Blue River Flood Inundation Web 

site contains a map of the forecast locations and a table that lists 

current stages for gages on the Blue River, the Missouri River 

gage at Kansas City, and NWS forecast peak stage, if available. 

The user can select one of the forecast locations from the table 

to access the web page specific to that location. Each forecast 

location web page has a graph depicting the most recent stage 

observations for that location, a locator map with the region 

highlighted for which the gage data are valid, and a drop-down 

menu used to select a particular flood-stage elevation of interest. Once the flood-stage elevation is selected, the flood-inundation map of the region for the flood-forecast location appears. 

The user can view flood-inundation maps of the region for other 

flood stages of interest by selecting a new stage from a dropdown menu. Each region is divided into sections to allow closer 

inspection of inundated areas. The user can click on a section to 

access a more detailed view of the flood-inundation map within 

that section. The current section appears and also is outlined on 

a small locator map. The user can navigate to adjacent sections 
Summary 27

within the region for which the gage data are valid at that stage 

by clicking on the desired section on the locator map. The user 

can view flood-inundation maps of the section for other flood 

stages of interest by selecting a new stage from a drop-down 

menu. To access flood-inundation maps for another region, the 

user can click on the main flood inundation page link at the bottom of the page and select another region. 

Summary

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

the city of Kansas City, Missouri, began a study in 2003 of the 

Blue River from Gregory Boulevard to the mouth to determine 

the estimated extent of flood inundation in the Blue River valley 

from flooding on the Blue River and from backwater inundation 

from flooding in the Missouri River for selected stage elevations above flood-stage elevation. Specific objectives of this 

project were to hydraulically model a complex stretch of the 

Blue River between 63rd Street and Blue Parkway to provide 

water velocity magnitudes and direction, and stage elevations in 

two dimensions, and create and provide access to estimated 

flood-inundation/water-depth maps and the National Weather 

Service (NWS) forecast stage for each forecast location on the 

World Wide Web for the lower Blue River in Kansas City, Missouri. 

Much of the lower Blue River flood plain is covered by 

industrial development. Rapid development in the upper end of 

the watershed has increased the volume of runoff, and thus the 

discharge of flood events for the Blue River. The small size of 

the basin causes flash floods and allows minimal time for flood 

forecasting and response. Modifications to the channel of the 

Blue River began in late 1983 in response to the need for flood 

control. By 2004, the channel had been widened and straightened from the mouth to just downstream from Blue Parkway. 

The NWS issues peak-stage forecasts for five locations on the 

lower Blue River and for the Missouri River at Kansas City during high water. 

A two-dimensional depth-averaged flow model, FESWMS Flo2DH, was used to simulate flooding within a 2-mile 

hydraulically complex study reach of the Blue River between 

63rd Street and Blue Parkway. Hydraulic simulations of the 

study reach provided design and performance information for 

proposed hydraulic structures and channel improvements, 

extent of inundation, and the areal distribution of water velocity 

and flow direction. To produce flood-inundation maps for the 

study reach, boundary conditions for high flows were calculated 

using an existing lower Blue River Hydraulic Engineering Centers River Analysis System (HEC-RAS) one-dimensional 

model. A secondary HEC-RAS model was constructed and calibrated to extend stage elevations from the upper end of the 

lower Blue River HEC-RAS model near the mouth of Brush 

Creek to the upstream face of the lower Blue Parkway Bridge. 

The constructed HEC-RAS model was calibrated to the discharge measurements. Discharge values associated with stage 

at the lower Blue Parkway Bridge were selected from the simulated rating curve and input into the two-dimensional model. 

Two-dimensional flood-inundation simulations incorporated 

design plans for the proposed Blue Parkway Bridge over the 

Blue River and Union Pacific Railroad. Twelve velocity magnitude and direction profiles were produced for the reach just 

downstream from 63rd Street, the middle of the study reach, and 

the reach just upstream from the lower Blue Parkway Bridge.

Flood profiles of the Blue River were developed from 

stage elevations and slopes calculated between Gregory Boulevard and 63rd Street from high-water marks from the flood of 

May 19, 2004, between 63rd Street and Blue Parkway from 

two-dimensional hydraulic modeling conducted for this study, 

and between Blue Parkway and the mouth from the lower Blue 

River HEC-RAS model. Twelve maps were produced at 2-ft 

(foot) intervals from 750 to 772 ft at the Kansas City, Missouri, 

ALERT gage at Blue Parkway to approximate the range of 

river-stage elevations from the 2- to 500-year flood frequencies. 

Missouri River backwater inundation profiles from flood-stage 

elevation to the highest historical stage elevation were developed using Missouri River stage elevations at the mouth of the 

Blue River. The USGS streamflow gage on the Missouri River 

at Kansas City, Missouri, is the reference gage for maps of Blue 

River backwater inundation caused by flooding on the Missouri 

River. At the mouth of the Blue River, a Missouri River stage 

elevation of 730.9 ft was used as the lowest flood elevation for 

generation of backwater-inundation maps. This river-surface 

elevation corresponds to an elevation of 738.4 ft at the USGS 

gage on the Missouri River at Kansas City, and a stage of 32 ft. 

Twelve backwater-inundation maps were produced at 2-ft intervals to include the historical range of Missouri River stages 

above flood stage for the Kansas City area. 

The flood-inundation maps created during this study represent a substantial increase in the capability of public officials 

and residents to minimize flood deaths and damage in the flood 

plain of the lower Blue River in Kansas City, and supplement 

information collected by metropolitan Kansas City flood-alert 

system. Data used to construct the flood-inundation maps 

include topographic data, one- and two-dimensional hydraulic 

model results, measured high-water marks, and interpolated 

stage elevations. 

To provide public access to the information presented in 

this report, a World Wide Web site (http://mo.water.usgs.gov/

indep/kelly/blueriver/index.htm) was created that displays the 

results of two-dimensional modeling between 63rd Street and 

Blue Parkway, flood-inundation maps, backwater-inundation

maps, and the latest gage heights and NWS stage forecast for

each forecast location within the study area. In addition, the full 

text of the report, tables, and plates are available for download. 

The Web site URL is http://pubs.water.usgs.gov/sir2006-5089/. 
28 Estimated Flood-Inundation Mapping for the Lower Blue River in Kansas City, Missouri, 2003–05

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Appendixes 1–4
Kelly and Rydlund, Jr.—Estimated Flood-Inundation Mapping for the Lower Blue River in the Kansas City, Missouri,—Scientific Investigations Report 2006–5089

2003–05