Prepared in cooperation with the Indiana Department of Transportation 

Flood-Inundation Maps for the Tippecanoe River near 

Delphi, Indiana

Pamphlet to accompany

Scientific Investigations Map 3243

U.S. Department of the Interior

U.S. Geological Survey
Cover:

Inset image: View of downstream, left bank from USGS streamgage 03332605, Tippecanoe River below Oakdale Dam, Indiana. (Photo taken 

by Chad Menke on March 12, 2009.) 

Background image: View of USGS streamgage 03333050, Tippecanoe River near Delphi, Indiana. (Photo taken by Brad T. Reinking on 

January, 14, 2008.)
Flood-Inundation Maps for the Tippecanoe 

River near Delphi, Indiana

By Chad D. Menke, Aubrey R. Bunch, and Moon H. Kim

Prepared in cooperation with the Indiana Department of Transportation 

Pamphlet to accompany

Scientific Investigations Map 3243 

U.S. Department of the Interior

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

KEN SALAZAR, Secretary

U.S. Geological Survey

Suzette M. Kimbal, Acting Director

U.S. Geological Survey, Reston, Virginia: 2013

For more information on the USGS—the Federal source for science about the Earth, its natural and living 

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

Suggested citation:

Menke, C.D., Bunch, A.R., and Kim, M.H., 2013, Flood-inundation maps for the Tippecanoe River near Delphi, Indiana: 

U.S. Geological Survey Scientific Investigations Map 3243, 13 sheets, 9-p. pamphlet, 

http://pubs.usgs/gov/sim/3243/.
iii

Acknowledgments

The authors wish to thank the many local, State, and Federal agencies that have cooperated in the funding for the operation and maintenance of the gages used for this study. Special 

thanks are given to the Indiana Department of Transportation for their cooperation with this 

report; the Indiana Department of Natural Resources, Division of Water, for their assistance 

with this study; and the National Weather Service for their continued support to the USGS 

flood-inundation mapping initiative. 
This page has been left blank intentionally. 
v

Contents

Acknowledgments........................................................................................................................................iii

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

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

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

Study Area Description........................................................................................................................2

Previous Studies ..................................................................................................................................2

Constructing Water-Surface Profiles.........................................................................................................2

Hydrologic and Steady-Flow Data .....................................................................................................4

Topographic/Bathymetric Data ..........................................................................................................4

Energy-Loss Factors.............................................................................................................................4

Model Calibration and Performance .................................................................................................4

Development of Water-Surface Profiles...........................................................................................6

Inundation Mapping ......................................................................................................................................6

Tippecanoe River, Indiana, Flood-Inundation Maps on the Internet............................................8

Disclaimer for Flood-Inundation Maps .............................................................................................8

Uncertainties and Limitations for Use of Flood-Inundation Maps................................................8

Summary..........................................................................................................................................................8

References Cited............................................................................................................................................9

Sheets

[Sheets and additional materials are available online at http://pubs.usgs.gov/sim/3243/.]

1–13. Flood-inundation maps for near Delphi, Indiana at the USGS streamgage 03333050 

on the Tippecanoe River for a corresponding stage of:

1. 6.00 feet and an elevation of 540.66 feet (NAVD 88)..................................................................

2. 7.00 feet and an elevation of 541.66 feet (NAVD 88)..................................................................

3. 8.00 feet and an elevation of 542.66 feet (NAVD 88)..................................................................

4. 9.00 feet and an elevation of 543.66 feet (NAVD 88)..................................................................

5. 10.00 feet and an elevation of 544.66 feet (NAVD 88)................................................................

6. 11.00 feet and an elevation of 545.66 feet (NAVD 88)................................................................

7. 12.00 feet and an elevation of 546.66 feet (NAVD 88)................................................................

8. 13.00 feet and an elevation of 547.66 feet (NAVD 88)................................................................

9. 14.00 feet and an elevation of 548.66 feet (NAVD 88)................................................................

10. 15.00 feet and an elevation of 549.66 feet (NAVD 88)................................................................

11. 16.00 feet and an elevation of 550.66 feet (NAVD 88)................................................................

12. 17.00 feet and an elevation of 551.66 feet (NAVD 88)................................................................

13. 18.00 feet and an elevation of 552.66 feet (NAVD 88)................................................................
vi

Figures

1. Map showing location of study reach for the Tippecanoe River and location of 

USGS streamgage sites...............................................................................................................3

Tables

1. USGS streamgage information for selected sites near Delphi, Indiana .............................4

2. Comparison of hydraulic-model output and measured stages at USGS streamgage 

03333050, Tippecanoe River near Delphi, Indiana...................................................................5

3. Comparison of hydraulic-model output and measured stages at USGS streamgage 

03332605, Tippecanoe River below Oakdale Dam, Indiana....................................................5

4. Discharge estimates for corresponding stages at selected locations along the 

Tippecanoe River near Delphi, Indiana, for simulated water-surface profiles ..................7

Conversion Factors

Inch/Pound to SI

Multiply By To obtain

Length

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

square mile (mi2

) 2.590 square kilometer (km2)

Flow rate

cubic foot per second (ft3

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

Hydraulic gradient

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

Vertical coordinate information is referenced to the North American Vertical Datum of 1988 

(NAVD 88).

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 vertical datum.
Flood-Inundation Maps for the Tippecanoe River near 

Delphi, Indiana

By Chad D. Menke, Aubrey R. Bunch, and Moon H. Kim

Abstract

Digital flood-inundation maps for an 11-mile reach of 

the Tippecanoe River that extends from County Road W725N 

to State Road 18 below Oakdale Dam, Indiana (Ind.), were 

created by the U.S. Geological Survey (USGS) in cooperation 

with the Indiana Department of Transportation. The inundation maps, which can be accessed through the USGS Flood 

Inundation Mapping Science Web site at http://water.usgs.

gov/osw/flood_inundation/, depict estimates of the areal extent 

of flooding corresponding to selected water levels (stages) at 

USGS streamgage 03333050, Tippecanoe River near Delphi, 

Ind. Current conditions at the USGS streamgages in Indiana 

may be obtained online at http://waterdata.usgs.gov/in/nwis/

current/?type=flow. In addition, the information has been 

provided to the National Weather Service (NWS) for incorporation into their Advanced Hydrologic Prediction Service 

(AHPS) flood warning system (http://water.weather.gov/ahps/). 

The NWS forecasts flood hydrographs at many places that are 

often co-located at USGS streamgages. That forecasted peakstage information, also available on the Internet, may be used 

in conjunction with the maps developed in this study to show 

predicted areas of flood inundation.

In this study, water-surface profiles were simulated for 

the stream reach by means of a hydraulic one-dimensional 

step-backwater model. The model was calibrated by using the 

most current stage-discharge relation at USGS streamgage 

03333050, Tippecanoe River near Delphi, Ind., and USGS 

streamgage 03332605, Tippecanoe River below Oakdale Dam, 

Ind. The hydraulic model was then used to simulate 13 watersurface profiles for flood stages at 1-foot intervals referenced 

to the streamgage datum and ranging from bankfull to approximately the highest recorded water level at the streamgage. 

The simulated water-surface profiles were then combined 

with a geographic information system digital elevation model 

(derived from Light Detection and Ranging (LiDAR) data) in 

order to delineate the area flooded at each water level. A floodinundation map was generated for each water-surface profile 

stage (13 maps in all) so that, for any given flood stage, users 

will be able to view the estimated area of inundation.

The availability of these maps, along with current stage 

from USGS streamgages and forecasted stream stages from 

the NWS, provides emergency management personnel and 

residents with information that is critical for flood response 

activities such as evacuations and road closures, as well as for 

post-flood recovery efforts.

Introduction 

The study area affected by flooding is a rural area 

northwest of Delphi, Indiana (Ind.), populated with riverside homes, cottages, and camps. In January 2008, a record 

flood occurred on the Tippecanoe River in the study area and 

resulted in evacuations and damage to more than 400 homes. 

A second flood of nearly equal severity occurred a month later, 

in February, causing further damage to many residences in the 

study area (Scott E. Morlock, U.S. Geological Survey, written 

commun., November 2012). 

Prior to this study, local officials relied on several information sources (many of which are available on the Internet) 

to make decisions on how to best alert the public and mitigate 

flood damages. One source is the Federal Emergency Management Agency (FEMA) Flood Insurance Study (FIS) for 

Carroll County, dated 1989 (Federal Emergency Management 

Agency, 1989). A second source of information is data from 

two USGS streamgages, 03333050 Tippecanoe River near 

Delphi, Ind., and 03332605, Tippecanoe River below Oakdale Dam, Ind., from which current or historical water levels 

(stage) can be obtained at http://waterdata.usgs.gov/in/nwis/

current/?type=flow. A third source is the National Weather 

Service’s forecast of peak stage at the USGS streamgages 

through the AHPS site at http://water.weather.gov/ahps/. 

Although USGS current stage and NWS forecast stage information is particularly useful for residents in the immediate 

vicinity of a streamgage, it is of limited use to residents farther 

upstream or downstream because the water-surface elevation 

is not constant along the entire stream channel. Also, FEMA 

and State emergency management mitigation teams or property owners typically lack information related to the depth of 

water at locations other than near USGS streamgage or NWS 

flood-forecast points. 
2 Flood-Inundation Maps for the Tippecanoe River near Delphi, Indiana

Purpose and Scope

The purpose of this report is to describe the development of a series of estimated flood-inundation maps for the 

Tippecanoe River near Delphi, Ind., and to provide maps and 

other useful flood information on the USGS Flood Inundation 

Mapping Science Web site at http://water.usgs.gov/osw/flood_

inundation/ and the NWS Advanced Hydrologic Prediction 

Service Web site at http:/water.weather.gov/ahps/. Internet 

users can select estimated inundation maps that correspond 

to (1) current stages at the USGS streamgage, (2) the NWS 

forecasted peak stage, or (3) other desired stream stages.

The scope of the study was limited to the Tippecanoe 

River between USGS streamgage 03333050, Tippecanoe River near Delphi, Ind., at State Route 18 and USGS 

streamgage 03332605, Tippecanoe River below Oakdale Dam, 

Ind. (fig. 1). Tasks specific to development of the maps were 

(1) collection of topographic data and geometric data (for 

structures and (or) bridges) throughout the study reach, (2) 

determination of energy-loss factors (roughness coefficients) 

in the stream channel and flood plain, and steady-flow data, 

(3) computation of water-surface profiles using the U.S. Army 

Corps of Engineers’ HEC-RAS computer program (U.S. Army 

Corps of Engineers, 2010), (4) production of estimated floodinundation maps at various stream stages using the U.S. Army 

Corps of Engineers’ HEC-GeoRAS computer program (U.S. 

Army Corps of Engineers, 2009) and a Geographic Information System (GIS), and (5) development of a Web interface 

that links to USGS real-time streamgage information and (or) 

NWS forecasted peak stage to facilitate the display of userselected flood-inundation maps on the Internet.

Methods used generally are cited from previously 

published reports (for example, Bales and others, 2007; and 

Whitehead and Ostheimer, 2009). If techniques varied significantly from previously documented methods due to local 

hydrologic conditions or available data, they are described 

in detail in this report. Maps were produced for water levels 

referenced to the water-surface elevation (stage) at USGS 

streamgage 03333050 Tippecanoe River near Delphi, Ind., 

and ranging from approximately bankfull to the approximate 

maximum observed water level at the streamgage. 

Study Area Description

The Tippecanoe River flows through the study area in 

the western part of Carroll County, in north-central Indiana. 

The drainage area ranges from 1,790 mi2 at USGS streamgage 

03332605, Tippecanoe River below Oakdale Dam, Ind., to 

1,869 mi2 at USGS streamgage 03333050, Tippecanoe River 

near Delphi, Ind. The headwaters originate from Tippecanoe 

Lake in Kosciusko County in north-central Indiana, and the 

stream flows generally southward. One major tributary to the 

Tippecanoe River (Big Creek) joins the main stem midway 

through the study reach. The study reach is approximately 

11 mi long; average top-of-bank channel width is about 280 ft, 

and an average channel slope is 2.6 ft/mi. The basin contiguous to the study reach is classified as rural and is populated 

with riverside homes, summer cottages, and recreational 

camps. The main channel within the study reach has two 

major road crossings that lie within the channel or the adjacent 

flood plain. 

Previous Studies 

The current FIS for Carroll County was completed by the 

U.S. Geological Survey in 1986 (Federal Emergency Management Agency, 1989). This study provided information on 

the 1.0-percent annual exceedance probability water-surface 

profiles and associated flood-plain maps for the Tippecanoe 

River. Estimates of the peak discharges for the 1.0-percent 

annual exceedance probability flood were documented for the 

Tippecanoe River at Oakdale Dam and at the Carroll County 

boundary with discharges of 25,500 ft3/s and 27,500 ft3/s, 

respectively (Federal Emergency Management Agency, 1989); 

the estimated drainage areas for the above locations were 

determined to be 1,790 mi2 and 1,892 mi2 respectively using 

Indiana StreamStats (http://water.usgs.gov/osw/streamstats/

indiana.html, accessed July 18, 2012). 

Constructing Water-Surface Profiles

The water-surface profiles used to produce the 13 

flood-inundation maps in this study were computed by using 

HEC-RAS, version 4.1.0 (U.S. Army Corps of Engineers, 

2010). HEC-RAS is a one-dimensional step-backwater model 

for simulation of water-surface profiles with steady-state 

(gradually varied) or unsteady-state flow computation options. 

The HEC-RAS analysis for this study was done by using the 

steady-state flow computation option.
Constructing Water-Surface Profiles 3

Projection: Transverse Mercator Horizontal coordinate information 

is referenced to the North American datum of 1983

Orthophotography from Indiana Spatial Data Portal, 

National Agriculture Imagery Program 2010, available at http://gis.iu.edu/

86°47' 86°46' 86°45' 86°44'

40°39'

40°38'

40°37'

40°36'

SPRINGBORO ROAD

WEST 725 NORTH 39

39

18

18

OAKDALE DAM

03333050

03332605

0 0.5 1 MILES

0 0.5 1 KILOMETERS

INDIANA

Study area

EXPLANATION

39

USGS streamgage and number

State route marker

Flow arrow—Indicates

direction of water flow

03333050

Creek

Lake Freeman

Big

Wallys 

Woods 

Lake

Tippecanoe

River

Figure 1. Location of study reach for the Tippecanoe River and location of USGS streamgage sites.
4 Flood-Inundation Maps for the Tippecanoe River near Delphi, Indiana

Hydrologic and Steady-Flow Data

The study area hydrologic network consists of two 

streamgages (fig. 1; table 1). Both gages were in operation 

prior to this study. Water level (stage) is measured continuously at each of the sites, and continuous records of streamflow are computed at both sites. All water-surface elevations 

are referenced to the North American Vertical Datum of 1988 

(NAVD 88). The gages are equipped with satellite radio transmitters that allow data to be transmitted routinely on the Internet within an hour of collection. USGS streamgage 03333050, 

Tippecanoe River near Delphi, Ind., is also equipped with a 

recording tipping-bucket rain gage. Flow data can be accessed 

at http://waterdata.usgs.gov/in/nwis/current/?type=flow by 

selecting the appropriate streamgage number.

Steady-flow data consisted of flow regime, boundary conditions (either known water-surface elevation associated with 

a discharge measurement, normal depth, or streamgage ratingcurve value), and peak-discharge information. The steady-flow 

data for the study reach were obtained from previous studies 

and field measurements of streamflow at USGS streamgage 

03333050, Tippecanoe River near Delphi, Ind. At gaged sites, 

all computations based on discharge values with known stages 

from actual streamflow measurements or stage-discharge relations were used.

Topographic/Bathymetric Data

 Channel cross sections were developed from USGS 

field surveys that were conducted in November and December 

2011; these cross sections provide detailed channel-elevation 

data below the water surface and were collected by using 

hydroacoustic instrumentation to measure depth and Differential Global Positioning System (DGPS) instrumentation to 

determine horizontal position. Light Detection and Ranging 

(LiDAR) data, collected in 2010 for Carroll County (David 

S. Nail, U.S. Geological Survey, written commun., October 

2010), was used to provide digital elevation data for the portions of the cross sections that were above the water surface at 

the time of the surveys. 

Various manmade structures (bridges, culverts, roadway 

embankments, and levees) in and along the stream affect or 

have the potential to affect water-surface elevations during 

floods along the stream. To properly account for these features in the model, bridge geometry was surveyed for the two 

bridges in the model. Both bridges were verified as current 

structures with pictures and elevation checks from digital-elevation model and field observations. A detailed description of 

the methods used to acquire and process the topographic and 

bathymetric data can be found in Bales and others (2007). 

Energy-Loss Factors

Field observations and high-resolution aerial photographs 

were used to select initial (pre-calibration) Manning’s roughness coefficients (“n” values) for energy-loss (friction-loss) 

calculations. The final Manning’s n values used were 0.04 for 

the main channel and 0.06 for the overbank areas modeled in 

this analysis. 

Model Calibration and Performance

The hydraulic model was calibrated to the most current 

stage-discharge relation at the USGS streamgages 03333050, 

Tippecanoe River near Delphi, Ind., and 0332605, Tippecanoe River below Oakdale Dam, Ind. The model calibration 

was accomplished by adjusting Manning’s n values and, 

in some cases, changing the channel cross section until the 

results of the hydraulic computations closely agreed with the 

known flood discharge and stage values. Differences between 

measured and simulated water levels for specified flows at 

USGS streamgage 03333050, Tippecanoe River near Delphi, 

Ind., were within 0.09 ft (table 2). Differences between measured and simulated water levels for specified flows at USGS 

streamgage 03332605, Tippecanoe River at Oakdale Dam, 

Ind., were within 0.36 ft (table 3). The results demonstrate that 

the model is capable of simulating accurate water levels over a 

wide range of flows in the basin. Details on techniques used in 

model development and calibration can be found in Bales and 

others (2007).

Table 1. USGS streamgage information for selected sites near Delphi, Indiana.

[mi2, square miles; NAD 83, North American Datum of 1983; NAVD 88, North American Vertical Datum of 1988; ft, feet]

Streamgage 

name

Streamgage 

number

Drainage area 

(mi2

) Latitude Longitude Period of record

Maximum flood elevation 

(ft above NAVD 88 

and date).

Tippecanoe River 

near Delphi, 

Indiana

03333050 1,869 40o35′38′′ 86o46′12′′ July 1939 to 

present

552.49 ft, Jan. 8, 2008.

Tippecanoe River 

at Oakdale Dam, 

Indiana

03332605 1,790 40o39′12′′ 86o 45′24′′ Dec. 2008 to 

present

578.53 ft, March 11, 2009.
Constructing Water-Surface Profiles 5

Table 2. Comparison of hydraulic-model output and measured stages at USGS streamgage 03333050, 

Tippecanoe River near Delphi, Indiana.

[ft, feet; NAVD 88, North American Vertical Datum of 1988]

Stage (ft)

Measured 

water-surface elevation 

(ft, NAVD 88)

Modeled 

water-surface elevation 

(ft, NAVD 88)

Elevation 

difference 

(ft)

6.00 540.66 540.75 -0.09

7.00 541.66 541.69 -0.03

8.00 542.66 542.58 0.08

9.00 543.66 543.58 0.08

10.00 544.66 544.71 -0.05

11.00 545.66 545.67 -0.01

12.00 546.66 546.66 0.00

13.00 547.66 547.62 0.04

14.00 548.66 548.61 0.05

15.00 549.66 549.69 -0.03

16.00 550.66 550.67 -0.01

17.00 551.66 551.65 0.01

18.00 552.66 552.62 0.04

Table 3. Comparison of hydraulic-model output and measured stages at USGS streamgage 03332605, 

Tippecanoe River below Oakdale Dam, Indiana

[ft, feet; NAVD 88, North American Vertical Datum of 1988; modeled water-surface elevations of 580.07 ft, 581.32 ft, and 

582.55 ft could not be compared because the rating was not extended to these elevations]

Stage (ft)

Measured 

water-surface elevation 

(ft, NAVD 88)

Modeled 

water-surface elevation 

(ft, NAVD 88)

Elevation 

difference 

(ft)

9.13 568.94 568.85 0.09

10.31 570.12 570.10 0.02

11.41 571.22 571.27 -0.05

12.59 572.4 572.38 0.02

13.72 573.53 573.51 0.02

14.48 574.29 574.58 -0.29

15.44 575.25 575.59 -0.34

16.78 576.59 576.58 0.01

17.52 577.33 577.54 -0.21

18.63 578.44 578.80 -0.36
6 Flood-Inundation Maps for the Tippecanoe River near Delphi, Indiana

Development of Water-Surface Profiles

Profiles were developed for a total of 13 stages at 1-ft 

intervals between 6.00 ft and 18.00 ft as referenced to USGS 

streamgage 03333050, Tippecanoe River near Delphi, Ind. 

Discharges corresponding to the various stages were obtained 

from the most current stage-discharge relation (rating no. 5.0) 

at this same streamgage. 

Models on the Tippecanoe River were calibrated to 

produce the selected profile elevations at USGS streamgage 

03333050 (table 4). Discharge at USGS streamgage 03332605, 

Tippecanoe River below Oakdale Dam, Ind., was determined 

by calculating cubic feet per second per square mile (CFSM) 

that corresponded to the measured discharges at USGS 

streamgage 03333050, Tippecanoe River near Delphi, Ind. The 

CFSM is defined as the average number of cubic feet of water 

per second flowing from each square mile of area drained by 

a stream, assuming that the runoff is distributed uniformly in 

time and area. 

The contributing drainage area to the river at the mouth 

of Big Creek accounts for the increase in discharge from the 

estimated discharge upstream at USGS streamgage 03332605 

and measured discharge downstream at USGS streamgage 

03333050. Drainage areas were calculated by using a Webbased GIS application called StreamStats (Ries and others), 

which can be accessed at

http://water.usgs.gov/osw/streamstats/indiana.html.

Inundation Mapping

Flood-inundation maps were created for USGS 

streamgage 03333050, Tippecanoe River near Delphi, Ind., 

which is also an NWS flood-forecast point. The maps were 

created in a GIS by combining the water-surface profiles and 

digital elevation model (DEM) data. The DEM data were 

derived from LiDAR data with 1.02-ft horizontal accuracy and 

a vertical accuracy of 0.37 ft (David S. Nail, U.S. Geological 

Survey, written commun., October 2010). The initial resolution of the DEM with 3.9-ft cell size was later resampled to 

10- by 10-ft cell size in order to reduce the GIS processing 

time. Estimated flood-inundation boundaries for each simulated profile were developed with HEC-GeoRAS software 

(U.S. Army Corps of Engineers, 2009). HEC-GeoRAS is a 

set of procedures, tools, and utilities for processing geospatial 

data in ArcGIS by using a graphical user interface (Whitehead 

and Ostheimer, 2009). The interface allows the preparation 

of geometric data for import into HEC-RAS and processes 

simulation results exported from HEC-RAS (U.S. Army Corps 

of Engineers, 2010). USGS personnel then modified the HEC- GeoRAS results to ensure a hydraulically reasonable transition 

of the boundary between modeled cross sections relative to the 

contour data for the land surface (Whitehead and Ostheimer, 

2009). The maps show estimated flood-inundated areas overlaid on high-resolution, georeferenced aerial photographs of 

the study area for each of the water-surface profiles that were 

generated by the hydraulic model.
Table 4. Discharge estimates for corresponding stages at selected locations along the Tippecanoe River near Delphi, Indiana, for simulated water-s[Numbers in parentheses reference NAVD 88; mi2, square miles; ft3/s, cubic feet per second]

 Stage, in feet above gage datum 

Location

Drainage area 

(mi2)

6.00

(540.66)

7.00

(541.66)

8.00

(542.66)

9.00

(543.66)

10.00

(544.66)

11.00

(545.66)

12.00

(546.66)

13.00

(547.66)

14.00

(548.66)

15.00

(549.66)

(5

Discharge (ft3/s)

USGS streamgage 

03333050

1,869 5,350 6,960 8,663 10,450 12,440 14,520 16,690 18,940 21,380 25,020 2

At mouth of Big 

Creek confluence

1,860 5,324 6,926 8,621 10,400 12,380 14,450 16,610 18,849 21,277 24,900 2

USGS streamgage 

03332605

1,790 5,124 6,666 8,297 10,008 11,914 13,906 15,985 18,139 20,476 23,962 2

Sheet no. 1 2 3 4 5 6 7 8 9 10 
8 Flood-Inundation Maps for the Tippecanoe River near Delphi, Indiana

Tippecanoe River, Indiana, Flood-Inundation 

Maps on the Internet

A USGS Flood Inundation Mapping Science World Wide 

Web portal has been established by the USGS to provide estimated flood-inundation information to the public (see http://

water.usgs.gov/osw/flood_inundation/). The maps and data 

from this study showing the extent of inundated areas can be 

downloaded in three electronic file formats from that portal: 

(1) GIS shapefile format, (2) Keyhole Markup Language 

(KML) file format, and (3) Portable Document Format (PDF). 

Users can print out formatted maps quickly or create a customized map using available GIS data layers. In addition, downloadable GIS raster files showing the depth of flooded areas 

are available at the Web portal. All PDF and KML maps show 

aerial photography beneath the flood layers. Each stream reach 

displayed on the Web site contains links to NWISWeb graphs 

of the current stage and streamflow at USGS streamgage 

03333050, Tippecanoe River near Delphi, Ind., to which the 

inundation maps are referenced. A link also is provided to the 

NWS AHPS site (http://water.weather.gov/ahps/) so that the 

user can obtain applicable information on forecasted peak 

stage. The estimated flood-inundation maps are displayed in 

sufficient detail to note the extent of flooding with respect to 

individual structures so that preparations for flooding and decisions for emergency response can be performed efficiently. 

Disclaimer for Flood-Inundation Maps

Inundated areas shown should not be used for navigation, 

regulatory, permitting, or other legal purposes. The USGS 

provides these maps “as-is” for a quick reference, emergency 

planning tool but assumes no legal liability or responsibility 

resulting from the use of this information.

Uncertainties and Limitations for Use of FloodInundation Maps

Although the flood-inundation maps represent the boundaries of inundated areas with a distinct line, some uncertainty 

is associated with these maps. The flood boundaries shown 

were estimated based on water stages and streamflows at 

selected USGS streamgages. Water-surface elevations along 

the stream reaches were estimated by steady-state hydraulic 

modeling, assuming unobstructed flow, and using streamflows and hydrologic conditions anticipated at the USGS 

streamgages. The hydraulic model reflects the land-cover characteristics and any bridge, dam, levee, or other hydraulic structures existing as of December 2011. Unique meteorological 

factors (timing and distribution of precipitation) may cause 

actual streamflows along the modeled reach to vary from those 

assumed during a flood, which may lead to deviations from 

the water-surface elevations and inundation boundaries shown. 

Additional areas may be flooded due to unanticipated conditions such as changes in the streambed elevation or roughness, 

backwater into major tributaries along a main-stem river, or 

backwater from localized debris or ice jams. The accuracy of 

the floodwater extent portrayed on these maps will vary with 

the accuracy of the digital elevation model used to simulate 

the land surface. Additional uncertainties and limitations pertinent to this study may be described elsewhere in this report.

If this series of flood-inundation maps will be used in 

conjunction with NWS river forecasts, the user should be 

aware of additional uncertainties that may be inherent or factored into NWS forecast procedures. The NWS uses forecast 

models to estimate the quantity and timing of water flowing 

through selected stream reaches in the United States. These 

forecast models (1) estimate the amount of runoff generated 

by precipitation and snowmelt, (2) simulate the movement 

of floodwater as it proceeds downstream, and (3) predict the 

flow and stage (and water-surface elevation) for the stream at 

a given location (AHPS forecast point) throughout the forecast 

period (every 6 hours and 3 to 5 days out in many locations). 

For more information on AHPS forecasts, please see http://

water.weather.gov/ahps/pcpn_and_river_forecasting.pdf. 

Summary

A series of estimated flood-inundation maps was developed in cooperation with the Indiana Department of Transportation for the Tippecanoe River in Indiana between State Road 

18 and Oakdale Dam. These maps, available at a USGS Web 

portal, in conjunction with the real-time stage data from USGS 

streamgage 03333050, Tippecanoe River near Delphi, Ind., 

and National Weather Service flood-stage forecasts, will help 

to guide the general public in taking individual safety precautions and will provide local officials with a tool to efficiently 

manage emergency flood operations and flood mitigation 

efforts. 

The maps were developed by using the U.S. Army Corps 

of Engineers’ HEC-RAS and HEC-GeoRAS programs to compute water-surface profiles and to delineate estimated floodinundation areas for selected stream stages. The maps show 

estimated flood-inundation areas overlaid on high-resolution, 

georeferenced aerial photographs of the study area for stream 

stages between 6.00 ft and 18.00 ft at USGS streamgage 

03333050, Tippecanoe River near Delphi, Ind. 
References Cited 

9

References Cited

Bales, J.D., Wagner, C.R., Tighe, K.C., and Terziotti, Silvia, 

2007, LiDAR-derived flood-inundation maps for realtime flood-mapping applications, Tar River Basin, North 

Carolina: U.S. Geological Survey Scientific Investigations 

Report 2007–5032, 42 p.

Federal Emergency Management Agency (FEMA), 1989, 

Flood insurance study, Carroll County, Indiana and unincor-

porated areas: Washington D.C., Flood Insurance Study 

no. 180019, 17 p., 3 pls., available at https://msc.fema.gov/.

Ries, K. G., III; Guthrie, J. G.; Rea, A. H.; Steeves, P. A.; 

Stewart, D. W., 2008. StreamStats: A water resources Web 

application, U.S. Geological Survey Fact Sheet 2008–3067, 

6 p., available at http://pubs.usgs.gov/fs/2008/3067/.

U.S. Army Corps of Engineers, 2009, HEC-GeoRAS, GIS 

tools for support of HEC-RAS using ArcGIS, user’s man-

ual, version 4.2: U.S. Army Corps of Engineers, Hydrologic 

Engineering Center [variously paged], available at http://

www.hec.usace.army.mil/software/hec-ras/documents/HECGeoRAS42_UsersManual.pdf.

U.S. Army Corps of Engineers, 2010, HEC-RAS River 

analysis system, hydraulic reference manual, version 4.1: 

U.S. Army Corps of Engineers, Hydrologic Engineering 

Center [variously paged], available at http://www.hec.usace.

army.mil/software/hec-ras/documents/HEC-RAS_4.1_

Reference_Manual.pdf.

U.S. Geological Survey, 2012, StreamStats data-collection 

station report, Tippecanoe River near Delphi, IN, accessed 

March 3, 2012, at http://streamstatsags.cr.usgs.gov/

gagepages/html/03333050.htm.

Whitehead, M.T., and Ostheimer, C.J., 2009, Development 

of a flood-warning system and flood-inundation mapping 

for the Blanchard River in Findlay, Ohio: U.S. Geological 

Survey Scientific Investigations Report 2008–5234, 9 p.

Menke and others—Flood-Inundation Maps for the Tippecanoe River near Delphi, Indiana—Scientific Investigations Map 3243