U.S. Department of the Interior

U.S. Geological Survey

Pamphlet to accompany

Scientific Investigations Map 3255

Prepared in cooperation with the Indiana Department of Transportation

Flood-Inundation Maps for the East Fork White River 

at Columbus, Indiana
Cover: Background photo is Eastbound Highway 46 arch bridge over East Fork White River in Columbus, Indiana, (by Hieu Nguyen, 

USGS, January, 2005). Inset image shows flood inundation at stage of 19.00 feet and elevation of 621.7 feet.
Flood-Inundation Maps for the East Fork 

White River at Columbus, Indiana

By Pamela J. Lombard

Prepared in cooperation with the Indiana Department of Transportation

Pamphlet to accompany

Scientific Investigations Map 3255

U.S. Department of the Interior

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

SALLY JEWELL, Secretary

U.S. Geological Survey

Suzette M. Kimball, Acting Director

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

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

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U.S. Government.

Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials 

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

Suggested citation:

Lombard, P.J., 2013, Flood-inundation maps for the East Fork White River at Columbus, Indiana: 

U.S. Geological Survey Scientific Investigations Map 3255, 15 sheets, 8-p. pamphlet,

http://pubs.usgs/gov/sim/2013/3255/. 
iii

Acknowledgments

The author wishes to thank the Indiana Department of Natural Resources for cooperating in the 

operation and maintenance of the East Fork White River at Columbus, Indiana, streamgage used 

for this study, and the Indiana Department of Transportation for providing bridge plans. In addition, thanks are given to the National Weather Service for their continued support of the U.S. 

Geological Survey flood-inundation mapping initiative.

v

Contents

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

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

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

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

Study Area Description........................................................................................................................4

Previous Studies ..................................................................................................................................4

Constructing Water-Surface Profiles.........................................................................................................4

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

Topographic and Bathymetric Data...................................................................................................4

Energy Loss Factors .............................................................................................................................5

Model Calibration and Performance .................................................................................................5

Development of Water-Surface Profiles...........................................................................................5

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

East Fork White River, Indiana, Flood-Inundation Maps on the Internet ....................................6

Disclaimer for Flood-Inundation Maps .............................................................................................6

Uncertainties and Limitations Regarding Use of Flood-Inundation Maps .................................6

Summary..........................................................................................................................................................7

References Cited ...........................................................................................................................................7

Figures

1. Map showing location of study reach for the East Fork White River at Columbus, 

Indiana, and location of U.S. Geological Survey streamgage and National Weather 

Service forecast site. ...................................................................................................................3

Tables

1. U.S. Geological Survey streamgage and miscellaneous site information for the 

study area, East Fork White River at Columbus, Indiana. .....................................................2

2. Estimates of annual exceedance probability peak discharges on the East Fork 

White River at Columbus, Indiana, station number 03364000................................................4

3. Stages with corresponding discharge estimates at the streamgage at East Fork 

White River at Columbus, Indiana, for simulated water-surface profiles...........................5
vi

Map Sheets

Separate documents available on Web only

1–15. Flood-inundation maps for the East Fork White River at Columbus, Indiana, 

corresponding to varying gage heights in feet (noted below) and varying elevations 

in feet (NAVD 88) (noted below) at U.S. Geological Survey streamgage 03364000

1. Gage height of 5.00 and an elevation of 607.7 feet

2. Gage height of 6.00 and an elevation of 608.7 feet

3. Gage height of 7.00 and an elevation of 609.7 feet

4. Gage height of 8.00 and an elevation of 610.7 feet

5. Gage height of 9.00 and an elevation of 611.7 feet

6. Gage height of 10.00 and an elevation of 612.7 feet

7. Gage height of 11.00 and an elevation of 613.7 feet

8. Gage height of 12.00 and an elevation of 614.7 feet

9. Gage height of 13.00 and an elevation of 615.7 feet

10. Gage height of 14.00 and an elevation of 616.7 feet

11. Gage height of 15.00 and an elevation of 617.7 feet

12. Gage height of 16.00 and an elevation of 618.7 feet

13. Gage height of 17.00 and an elevation of 619.7 feet

14. Gage height of 18.00 and an elevation of 620.7 feet

15. Gage height of 19.00 and an elevation of 621.7 feet

Conversion Factors

Inch/Pound to SI

Multiply By To obtain

Length

inch (in) 25.4 millimeter (mm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

square foot (ft2

) 0.0929 square meter (m2)

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).
Flood-Inundation Maps for the East Fork White River at 

Columbus, Indiana

By Pamela J. Lombard 

Abstract

Digital flood-inundation maps for a 5.4-mile reach of 

the East Fork White River at Columbus, Indiana, from where 

the Flatrock and Driftwood Rivers combine to make up East 

Fork White River to just upstream of the confluence of Clifty 

Creek with the East Fork White River, 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 03364000, East Fork White River at Columbus, 

Indiana. Current conditions at the USGS streamgage may be 

obtained on the Internet from the USGS National Water Information System (http://waterdata.usgs.gov/in/nwis/uv/?site_

no=03364000&agency_cd=USGS&). The National 

Weather Service (NWS) forecasts flood hydrographs for the 

East Fork White River at Columbus, Indiana at their Advanced 

Hydrologic Prediction Service (AHPS) flood warning system 

website (http://water.weather.gov/ahps/), that may be used in 

conjunction with the maps developed in this study to show 

predicted areas of flood inundation.

In this study, flood profiles were computed for the stream 

reach by means of a one-dimensional step-backwater model. 

The hydraulic model was calibrated by using the most current stage-discharge relation at USGS streamgage 03364000, 

East Fork White River at Columbus, Indiana. The calibrated 

hydraulic model was then used to determine 15 water-surface 

profiles for flood stages at 1-foot (ft) 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), 

having a 0.37-ft vertical accuracy and a 1.02 ft horizontal 

accuracy), in order to delineate the area flooded at each water 

level.

The availability of these maps, along with Internet information regarding current stage from the USGS streamgage 

at Columbus, Indiana, and forecasted stream stages from the 

NWS will provide 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 East Fork White River flows south from where it 

begins at the confluence of the Flatrock and Driftwood Rivers 

west of the City of Columbus in Bartholomew County, Indiana, through Bartholomew County and then southwest through 

Lawrence, Jackson, and Martin Counties. It then heads west 

as it enters Davies County and forms the southern border of 

Davies County until it joins the White River north of Petersburg, Indiana. 

The peak discharge from the highest stage of 

17.9 feet (ft) recorded at the East Fork White River at 

Columbus streamgage occurred in March 1913 and was 

estimated to be 100,000 cubic feet per second (ft3

/s). 

The 1913 peak flow estimate was before the period 

of continuous record at the streamgage location. The 

measured peak discharges (and stages) for other large 

flows including the 1937, 1963, 2005, and 2008 floods 

were 51,000 ft3/s (15.1 ft), 52,300 ft3/s (16.23 ft), 

57,300 ft3/s (17.05 ft), and 68,100 ft3/s (18.61 ft), respectively. 
2 Flood-Inundation Maps for the East Fork White River at Columbus, Indiana

Prior to this study, Columbus officials relied on several 

information sources (all 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 City 

of Columbus (Federal Emergency Management Agency, 1996) 

and the preliminary FIS for Bartholomew County (Federal 

Emergency Management Agency, written commun., 2012). A 

second source is U.S. Geological Survey (USGS) streamgage 

03364000. East Fork White River at Columbus, Indiana, 

from which current and historical water levels (stage) can be 

obtained. A third source is the National Weather Service’s 

(NWS) forecast of peak stage at USGS streamgage 03364000, 

East Fork White River at Columbus, Indiana, through their 

Advanced Hydrologic Prediction Service (AHPS) Web site. 

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 how deep 

the water is at locations other than near USGS streamgage or 

NWS flood-forecast points. 

Purpose and Scope

The purpose of this report is to describe the development 

of a series of estimated flood-inundation maps for the East 

Fork White River at Columbus, Indiana. The maps and other 

useful flood information are available on the USGS Flood 

Inundation Mapping Science Web site. Internet users can 

select estimated inundation maps that correspond to (1) current stages at the USGS streamgage, (2) NWS forecasted peak 

stage, or (3) other desired stream stages. 

The scope of the study was limited to a 5.4-mile reach of 

the East Fork White River at Columbus (fig. 1). To develop 

flood-inundation maps, a hydraulic model of the East Fork 

White River reach was built that provided water-surface profiles for various flood stages. 

Methods used are generally cited from previously 

published reports. If techniques varied significantly from 

previously documented methods owing 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 East Fork White River 

at Columbus and range from approximately bankfull to the 

maximum observed water level at the streamgage. 

Table 1. U.S. Geological Survey streamgage and miscellaneous site information for the study area, East Fork White River at Columbus, 

Indiana. 

[mi2, square mile; ft, foot; NAVD 88, North American Vertical Datum of 1988; °, degrees; ʼ, minutes; ˮ, seconds]

Station name Station 

number

Drainage 

area 

(mi2

)

Latitude Longitude Period 

of record

Maximum recorded 

flood elevation at gage 

(ft above NAVD 88) 

and date

East Fork White River 

at Columbus

03364000 1,707 39°12’00” 85°55’32” 1948 to 2012 621.33, June 8, 2008.1

1

Current streamgage datum is 602.72 ft above NAVD 88. Conversion from NAVD 88 to National Geodetic Vertical Datum of 1929 is +0.4 ft at this location.
Introduction 3

Figure 1. Location of study reach for the East Fork White River at Columbus, Indiana, and location of U.S. Geological Survey 

streamgage and National Weather Service forecast site.

0 0.5 1 KILOMETERS

0 0.5 1 MILES Projection: Indiana State Plane Eastern Zone

Horizontal coordinate information is referenced to the North American Datum of 1983

Orthophotography from Esri ArcGIS World Imagery, 2011, 

available at http://goto.arcgisonline.com/maps/World_Imagery

85°57' 85°56' 85°55' 85°54' 85°53'

39°13'

39°12'

39°11'

39°10'

39°09'

03364000

JONESVILLE ROAD

WEST JONATHAN MOORE PIKE

Columbus

Garden City

3RD STREET

2ND STREET

White

River

East

Fork

Clifty

Creek

Driftwood

River

River

Flatrock

Haw

Creek

46

46

46

46

65

EXPLANATION

46

USGS Streamgage and 

 number

Limit of study area

State route marker

Flow arrow—Indicates 

 directionof water flow

03364000

65 Interstate route marker

11

65

INDIANA

Study area
4 Flood-Inundation Maps for the East Fork White River at Columbus, Indiana

Study Area Description

The City of Columbus is located in central Bartholomew 

County and is surrounded by unincorporated areas of Bartholomew County. The estimated population of Columbus, 

according to the 2010 U.S. Census, was 45,578 (U.S. Census 

Bureau, 2011). The Flatrock River and the East Fork White 

River border the City of Columbus on the west. The Driftwood River, from the northwest, and the Flatrock River, from 

the north-northeast, converge and form the East Fork White 

River near the southwest corner of the city. Haw Creek flows 

through the City of Columbus and joins the East Fork White 

River approximately 2 miles (mi) south of the confluence of 

the Driftwood and Flatrock Rivers. Clifty Creek flows in a 

southwesterly direction along the extreme eastern part of the 

city and discharges into the East Fork White River approximately 4 mi downstream from its junction with Haw Creek, 

and just downstream of the studied reach. Most of the residential properties and the larger part of the business section of 

the city are located on high ground, but there are commercial 

and some industrial establishments on the flood plains of 

the Driftwood and Flatrock Rivers. Development along the 

flood plains of Clifty Creek and the Flatrock River is partially 

residential. The flood plains of the Driftwood River and the 

East Fork White River are primarily agricultural, except for an 

industrial site along Interstate Highway 65. The Haw Creek 

flood plain is primarily clear, with a little development consisting of a mixture of industrial, residential, and commercial 

development.

The drainage area of the East Fork White River is 

1,707 square miles (mi2

) at the Columbus streamgage. The 

basin terrain is generally flat. The study reach is approximately 

5.4 mi long and has an average top-of-bank channel width 

of 240 ft and an average channel slope of 0.0004. The main 

channel within the study reach has two road crossings and 1 

railroad crossing. 

Previous Studies 

The current FIS for the City of Columbus (Federal 

Emergency Management Agency, 1996) was completed by the 

U.S. Army Corps of Engineers for FEMA in 1996. That study 

provided information on the 10-, 2-, 1-, and 0.2-percent annual 

exceedance probability water-surface profiles and discharges. 

Hydrologic and hydraulic information from the 1996 publication will be incorporated into the Bartholomew County publication by FEMA (Federal Emergency Management Agency, 

2012, written commun.) (table 2).

Constructing Water-Surface Profiles

The water-surface profiles used to produce the 15 floodinundation 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.

Hydrologic and Steady-Flow Data

The study area hydrologic network consists of one USGS 

streamgage (fig. 1; table 1), which has been in operation since 

1948. This gage has a continuous record of measured water 

level (stage) and computed streamflow. All water-surface 

elevations are referenced to North American Vertical Datum 

of 1988 (NAVD 88). Conversion from NAVD 88 to National 

Geodetic Vertical Datum of 1929 is approximately 0.4 ft at 

this location. The streamgage is equipped with satellite radio 

transmitters that allow data to be transmitted routinely on the 

Internet within 2 hours of collection. 

Steady-flow data consisted of flow regime, boundary conditions (normal depth slope was set to 0.0003), and peak discharge information. The steady-flow data for the study reach 

were obtained from field measurements and stage-discharge 

rating calculations made by USGS personnel at the East Fork 

White River at Columbus streamgage. 

Topographic and Bathymetric Data

 Channel cross sections were developed from USGS field 

surveys that were conducted in September 2011. Detailed 

channel depths below the water surface were collected by 

using hydroacoustic instrumentation, while differential Global 

Positioning System (DGPS) instrumentation was used to 

determine horizontal position. Cross-section elevation data 

were obtained from a digital elevation model (DEM) that was 

derived from Light Detection and Ranging (LiDAR) data that 

Table 2. Estimates of annual exceedance probability peak 

discharges on the East Fork White River at Columbus, Indiana, 

station number 03364000 (from Federal Emergency Management 

Agency, 1996).

[ft3/s, cubic foot per second]

Annual exceedance probability 

(percent)

Discharge estimate 

(ft3

/s)

10 47,000

2 69,000

1 79,000

0.2 105,000
Constructing Water-Surface Profiles 5

were collected as part of this project during April 2010, by 

Aero-Metric, Inc., Sheboygan, Wisconsin. Post-processing of 

these data was completed by Aero-Metric, Inc., on July 14, 

2010 (Aero-Metric, Inc., 2010). The original LiDAR data have 

horizontal accuracy of 1.02 ft (31 centimeters) with horizontal resolution of 3.9 ft (1.2 meters) and vertical accuracy of 

0.37 ft at a 95-percent confidence level for the “open terrain” land-cover category (root mean squared error of 0.19 ft 

(5.8 centimeters)). Although a finer resolution of the DEM was 

possible given the accuracy of the LiDAR data, the final DEM 

had a grid-cell size of 10 square feet (ft2) in order to decrease 

the geographic information system (GIS) processing time. 

Three bridges in Columbus have the potential to affect 

water-surface elevations during high water along the East 

Fork White River in the studied reach. To properly account for 

these features in the model, bridge geometry was taken from 

a previous HEC-2 step-backwater model (Federal Emergency 

Management Agency, 1996) and from bridge plans received 

from Indiana Department of Transportation (IN DOT) (Teresa 

Hammons, Indiana Department of Transportation, written 

commun., 2012). All three bridges were verified as current 

structures with pictures and elevation checks from the DEM 

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 (friction) loss calculations. Manning’s n values were determined to be 0.045–0.05 

for the main channel, and 0.087 for the overbank areas. It was 

determined that roughness coefficients varied with stage for 

this reach of the East Fork White River. Values were increased 

by a factor of 1.29 or decreased by a factor of 0.81 depending on the flow, and generally increased with increasing flow. 

Although typically roughness coefficients decrease with 

increasing flow, the increases could be owing to increased vegetation in the overbanks.

Model Calibration and Performance

The hydraulic model was calibrated to the most current 

stage-discharge relation at USGS streamgage 03364000, East 

Fork White River at Columbus, Indiana. Model calibration 

was accomplished by adjusting Manning’s n values 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 were 

equal to or less than 0.1 ft. 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).

Development of Water-Surface Profiles

Profiles were developed for a total of 15 stages at 

1-ft intervals between 5 and 19 ft as referenced to USGS 

streamgage 03364000, East Fork White River at Columbus, 

Indiana. Discharges corresponding to the various stages were 

obtained from the most current stage-discharge relation at 

the East Fork White River gage, which is in the upper end 

of the 5.4 mi reach. Although Haw Creek enters East Fork 

White River within the study reach, its drainage area is only 

3.2 percent of the East Fork White River drainage area; thus, 

it was considered negligible in terms of additional flow during a flood. Discharges for each profile were held constant 

throughout the reach (table 3). Clifty Creek enters East Fork 

White River downstream of the studied reach and thus was not 

included in the model or mapping. 

Table 3. Stages (elevations referenced to streamgage datum 

and to NAVD 88) with corresponding discharge estimates at the 

streamgage at East Fork White River at Columbus, Indiana, for 

simulated water-surface profiles.

[NAVD 88, North American Vertical Datum of 1988; ft3/s, cubic foot per 

second]

Stage 

(feet above 

gage datum)

Elevation 

(feet, NAVD 88)

Discharge 

(ft3

/s)

5 607.7 10,160

6 608.7 11,460

7 609.7 13,030

8 610.7 14,600

9 611.7 16,800

10 612.7 20,480

11 613.7 24,540

12 614.7 28,980

13 615.7 33,810

14 616.7 39,020

15 617.7 44,620

16 618.7 50,620

17 619.7 57,000

18 620.7 63,800

19 621.7 71,000
6 Flood-Inundation Maps for the East Fork White River at Columbus, Indiana

Inundation Mapping

Flood-inundation maps were created for the reach surrounding USGS streamgage 03364000, which is currently 

(2012), an NWS flood-forecast point. The maps were created 

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

data. The DEM data were derived from LiDAR data that had 

a horizontal accuracy of 1.02 ft and a vertical accuracy of 

0.37 ft. 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. 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 throughout the reach. The 

resulting inundation maps have a vertical accuracy of about 

1 ft. 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.

East Fork White 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 two electronic file formats from that portal: 

(1) GIS shapefile format, and (2) 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 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 stream-flow at USGS streamgage 

03364000, East Fork White River at Columbus, Ind., to which 

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

the NWS Advanced Hydrologic Prediction Service (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 Regarding Use of 

Flood-Inundation 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 (water-surface elevations) and streamflows at USGS streamgage 03364000, 

East Fork White River at Columbus, Indiana. Water-surface 

elevations along the stream reach were estimated by steadystate hydraulic modeling, assuming unobstructed flow, and 

using streamflows and hydrologic conditions anticipated at 

the USGS streamgage. The hydraulic model reflects the landcover characteristics, bridges, and other hydraulic structures 

existing as of September, 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 in the 

water-surface elevations and inundation boundaries shown. 

Additional areas may be flooded owing 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 DEM used to simulate the land surface. 

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 (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. 
References Cited 7

Summary

A series of estimated flood-inundation maps were 

developed in cooperation with the Indiana Department of 

Transportation for a 5.4-mile reach of the East Fork White 

River Columbus, Indiana, from the confluence of the Flatrock and Driftwood Rivers to just upstream of the confluence 

of Clifty Creek. These maps, available at a U.S. Geological Survey (USGS) Web portal (http://water.usgs.gov/osw/

flood_inundation/ ). These maps, in conjunction with the 

real-time stage data from USGS streamgage 03364000, East 

Fork White River at Columbus, Indiana, and National Weather 

Service flood-stage forecasts, will help to guide the general 

public in taking individual safety precautions and will provide 

city 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 

flood-inundation areas for selected stream stages. The maps 

show estimated (shaded) flood-inundation areas overlaid on 

high-resolution, georeferenced, aerial photographs of the study 

area for stream stages between 5 and 19 feet at the East Fork 

White River streamgage. GIS Shapefiles showing the extent 

of the inundated area, and GIS raster files showing the depth 

of the inundated areas are also available for download at the 

USGS web portal.

References Cited 

Aero-Metric, Inc., 2010, Indiana Flood LiDAR (ARRA) Task 

Order, Remote-sensing Image: Sheboygan, Wis., 

Aero-Metric, Inc.

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, 1996, Flood Insurance Study, City of Columbus, Bartholomew County, 

Indiana: Washington D.C. Flood Insurance Study Number 

January 5, 1996.

U.S. Army Corps of Engineers, Hydrologic Engineering 

Center, 2009, HEC-GeoRAS, GIS tools for support of 

HEC–RAS using ArcGIS, user’s manual, version 4.2 

[variously paged]. Available at http://www.hec.usace.

army.mil/software/hec-ras/documents/HEC-GeoRAS42_

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