U.S. Department of the Interior

U.S. Geological Survey

Pamphlet to accompany

Scientific Investigations Map 3210

Prepared in cooperation with Camp Atterbury Joint Maneuver Training Center, Edinburgh, Indiana

Flood-Inundation Maps for the Driftwood River and 

Sugar Creek near Edinburgh, Indiana
Cover. Hendricks Ford Bridge over the Driftwood River, near Edinburgh, Ind. 

 (Photograph by Chad Menke, USGS, January 2011).
Flood-Inundation Maps for the Driftwood 

River and Sugar Creek near Edinburgh, 

Indiana

By Kathleen K. Fowler, Moon H. Kim, and Chad D. Menke

Pamphlet to accompany

Scientific Investigation Map 2012–3210 

U.S. Department of the Interior

U.S. Geological Survey

Prepared in cooperation with Camp Atterbury Joint Maneuver Training Center, 

Edinburgh, Indiana
U.S. Department of the Interior

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2012

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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.

Suggested citation:

Fowler, K.K., Kim, M.H., and Menke, C.D., 2012, Flood-inundation maps for the Driftwood River and Sugar Creek 

near Edinburgh, Indiana: U.S. Geological Survey Scientific Investigations Map 3210, 8 p. pamphlet, 9 sheets, 

scale 1:54,000. 
iii

Contents

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

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

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

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

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

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

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

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

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

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

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

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

Driftwood River and Sugar Creek, Indiana, Flood-Inundation Maps on the Internet................7

Disclaimer for Flood-Inundation Maps .............................................................................................7

Uncertainty Associated with Inundation Maps...............................................................................7

Acknowledgments.........................................................................................................................................8

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

References Cited............................................................................................................................................8

Figure

1. Location of study reaches for the Driftwood River and Sugar Creek, and 

location of USGS streamgage sites...........................................................................................3

Tables

1. USGS Streamgage information for sites near Edinburgh, Indiana.......................................4

2. Comparison of measured water-surface elevations at USGS streamgage 

03363000 Driftwood River near Edinburgh, Indiana, with water-surface 

elevations output from the hydraulic model.............................................................................5

3. Comparison of measured water-surface elevations at USGS streamgage 

03362500 Sugar Creek near Edinburgh, Indiana, with water-surface elevations 

output from the hydraulic model ................................................................................................5

4. Stages and water-surface elevations, in feet, with corresponding discharge 

estimates at selected locations for the Driftwood River near Edinburgh, Indiana, 

for simulated water-surface profiles.........................................................................................6

5. Stages and water-surface elevations, in feet, with corresponding discharge 

estimates at selected locations for Sugar Creek near Edinburgh, Indiana, for 

simulated water-surface profiles...............................................................................................6
iv

Map Sheets

1–9. Flood-inundation maps for Driftwood River and Sugar Creek near Edinburgh, 

Indiana, Corresponding to Varying Stages in Feet (noted below) and Varying 

Elevations in Feet (NAVD88) at the U.S. Geological Survey Streamgage 03363000

 1. Stage of 9.00 and an elevation of 645.60 feet............................................................... link

 2. Stage of 10.00 and an elevation of 646.60 feet............................................................. link

 3. Stage of 11.00 and an elevation of 647.60 feet............................................................. link

 4. Stage of 12.00 and an elevation of 648.60 feet............................................................. link

 5. Stage of 13.00 and an elevation of 649.60 feet............................................................. link

 6. Stage of 14.00 and an elevation of 650.60 feet............................................................. link

 7. Stage of 15.00 and an elevation of 651.60 feet............................................................. link

 8. Stage of 16.00 and an elevation of 652.60 feet............................................................. link

 9. Stage of 17.00 and an elevation of 653.60 feet............................................................. link
v

 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

) 0.09290 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 either (1) stage, the height above an arbitrary datum established at 

a streamgage, or (2) elevation, the height above North American Vertical Datum of 1988 (NAVD 88). Horizontal 

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

Inch/Pound to SI

Conversion Factors

Abstract

Digital flood-inundation maps for an 11.2 mile reach of 

the Driftwood River and a 5.2 mile reach of Sugar Creek, both 

near Edinburgh, Indiana, were created by the U.S. Geological 

Survey (USGS) in cooperation with the Camp Atterbury Joint 

Maneuver Training Center, Edinburgh, Indiana. 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 the 

USGS streamgage 03363000 Driftwood River near Edinburgh, 

Ind. Current conditions at the USGS streamgage in Indiana 

may be obtained on the Internet 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 at http:/water.weather.

gov/ahps/. The NWS forecasts flood hydrographs at many 

places that are often collocated at USGS streamgages. That 

forecasted peak-stage 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.

For this study, flood profiles were computed for the 

stream reaches by means of a one-dimensional step-backwater 

model. The model was calibrated using the most current 

stage-discharge relations at the USGS streamgage 03363000 

Driftwood River near Edinburgh, Ind. The hydraulic model 

was then used to determine elevations throughout the study 

reaches for nine water-surface profiles for flood stages at 1-ft 

intervals referenced to the streamgage datum and ranging 

from bankfull to nearly the highest recorded water level at the 

USGS streamgage 03363000 Driftwood River near Edinburgh, 

Ind. The simulated water-surface profiles were then combined 

with a geospatial digital elevation model (derived from Light 

Detection and Ranging (LiDAR) data) in order to delineate the 

area flooded at each water level.

The availability of these maps along with real-time 

information available online regarding current stage from 

USGS streamgages and forecasted stream stages from the 

NWS 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 Camp Atterbury Joint Training and Maneuvers 

Center, hereafter known as Camp Atterbury, is the home base 

for members of the Army National Guard and Army Reserves, 

Marine Corps, and other units that train and mobilize at Camp 

Atterbury. Camp Atterbury also serves as a training site for 

both individuals and units from all branches of service for 

both Reserve and Active Duty training and other special 

training events. In recent years Camp Atterbury has mobilized 

over 50,000 and demobilized over 30,000 soldiers, sailors, 

and airmen for duty in the United States and overseas. The 

facility has live fire ranges along with more than 33,000 acres 

of maneuver training area and dozens of artillery and mortar 

firing points (http://www.campatterbury.in.ng.mil/AboutUs/

tabid/691/Default.aspx, accessed Oct. 21, 2011). 

Camp Atterbury has a varying population depending on 

military activities at any particular time. The area has undergone flooding numerous times; most notably in 2008. The 

majority of flood damages have occurred along the Driftwood 

River, Sugar Creek, and a tributary to the Driftwood River, 

Nineveh Creek. Flood plains along the study reach are moderately developed and contain a mix of military, residential, 

agricultural, and forested areas. The town closest to Camp 

Atterbury is Edinburgh, Indiana, with a population of approximately 4,480 people in the 2010 census (U.S. Census Bureau, 

2010).

Prior to this study, Camp Atterbury officials have relied 

on several information sources to make decisions on how to 

best alert the public and military personnel and to mitigate 

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

Bartholomew and Johnson Counties dated September 15, 

1981, and August 2, 2007 respectively (Federal Emergency 

Management Agency, 1981, 2007). A second source of information is the USGS streamgage 03362500 Sugar Creek near 

Edinburgh, 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/ahps2/

index.php?wfo=ind. Although USGS current stage and NWS 

information is useful for residents in the immediate vicinity of 

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

Flood-Inundation Maps for the Driftwood River and 

Sugar Creek near Edinburgh, Indiana

By Kathleen K. Fowler, Moon H. Kim, and Chad D. Menke
2 Flood-Inundation Maps for the Driftwood River and Sugar Creek near Edinburgh, Indiana

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 streamgages or NWS floodforecast points. 

Purpose and Scope

The purpose of this report is to describe the development 

of a series of estimated flood-inundation maps for the Driftwood River and Sugar Creek near Camp Atterbury, Edinburgh, 

Indiana, and to make these maps available to emergency 

workers and the public on the USGS Flood Inundation Mapping Science Web site available at http://water.usgs.gov/osw/

flood_inundation/. The purpose is to (1) provide users with a 

library of flood-inundation maps that correspond to a range of 

flood elevations on rivers near Camp Atterbury, and (2) provide links between NWS forecasted peak stage at streamgages 

during times of flood and the corresponding flood-inundation 

map that shows what that forecast stage will look like on the 

ground.

The scope of the study was limited to approximately 

11.2 miles (mi) of the Driftwood River, 5.2 mi of Sugar Creek, 

and 1.1 mi of the Big Blue River for a total of 17.5 mi. The 

upstream extent of the Driftwood River begins at the confluence of Sugar Creek and the Big Blue River and ends at a 

location about 0.6 mi downstream of W. Lowell Road. The 

upstream extent of Sugar Creek begins at a location about 

0.5 mi upstream of the U.S. Government Railroad Bridge and 

ends at its confluence with Big Blue and Driftwood River. The 

short reach of the Big Blue River begins at the U.S. Highway 

31 Bridge down to the confluence with Sugar Creek and was 

included for modeling and mapping continuity (fig. 1). 

Development of the inundation maps was accomplished 

by first constructing water-surface profiles for the study reach. 

Constructing water-surface profiles included (1) re-establishment of the streamgage on the Driftwood River and examination of current and historical data from streamgages on the 

Driftwood River and Sugar Creek (table 1); (2) collection of 

hydrologic and steady flow data; (3) collection of topographic, 

geometric (for structures/bridges), and bathymetric data 

throughout the study reach; (4) determination of energy-loss 

factors (roughness coefficients) in the stream channel and 

flood plain; (5) model calibration and evaluation and (6) computation of water-surface profiles using the U.S. Army Corps 

of Engineer’s HEC–RAS computer program (U.S. Army 

Corps of Engineers, 2010). 

Flood-inundation maps were then produced from the 

results of the modeled water-surface profiles. Production of 

estimated flood-inundation maps corresponding to targeted 

water-surface elevations at the gages was done using the 

U.S. Army Corps of Engineer’s HEC–GeoRas computer 

program (U.S. Army Corps of Engineers, 2009) and a Geographic Information System (GIS). An interface tool that links 

to USGS real-time streamgage information and (or) NWS 

forecasted peak stage to facilitate the online display of userselected flood-inundation maps was developed. 

Techniques that varied significantly from previously 

documented methods due to local hydrologic conditions or 

available data are described in detail in this report. Maps were 

produced for inundation levels referenced to the stage at the 

USGS streamgage 03363000 Driftwood River near Edinburgh, 

Ind., and range from approximately bankfull to near the maximum recorded water level at the gage site.

Study Area Description

The Driftwood River, and those portions of Sugar Creek 

and Big Blue River that are included in this study, are in south 

central Indiana near the northern tip of the Scottsburg Lowland physiographic division. The USGS streamgage 03363000 

Driftwood River near Edinburgh, Ind., hereafter referred to 

as the Driftwood River gage, is in Bartholomew County and 

the USGS streamgage 03362500 on Sugar Creek near Edinburgh, Ind., hereafter referred to as the Sugar Creek gage, is 

in Johnson County. The Driftwood River is one of the shortest rivers in Indiana with a length of 16 miles. The Driftwood 

River originates in the southernmost part of Johnson County, 

and flows generally southward before flowing into the East 

Fork White River in Columbus, Ind. There are two major 

tributaries to the Driftwood River that join the main stem as it 

flows along the boundary of Camp Atterbury: Nineveh Creek 

and Muddy Branch Creek. The basin terrain is generally broad 

terraced valleys and low till-covered hills. The drainage area 

of the Driftwood River study reach ranges from 1,058 square 

miles (mi2

) at the upstream end (the confluence of Sugar Creek 

and Big Blue River) to 1,137 mi2 at the downstream extent of 

the study reach. The Driftwood River reach is approximately 

11.2 mi long, has an average top-of-bank channel width of 

about 220 feet (ft) and an average channel slope of 2.5 feet 

per mile (ft/mi). The Driftwood River winds through farmlands with wooded areas along both banks. The upper reach 

is mostly natural while the lower reach shows some development. The main channel within the study reach has three major 

road crossings: Hendricks Ford Road, Tannehill Road, and 

West Lowell Road. 

Sugar Creek originates in Henry County and the river 

flows generally southward before joining the Big Blue River 

to form the Driftwood River. The drainage area of the Sugar 

Creek study reach ranges from 468 mi2

 at the upstream extent 

to 474 mi2 at the downstream extent. This part of the study 

reach is about 5.2 mi. in length and is entirely in Johnson 

County. In the study area, Sugar Creek has an average top-ofbank channel width of about 160 ft and an average channel 

slope of 3.5 ft/mi. Near the Camp Atterbury property, Sugar 

Creek flows through mostly forested lowlands and undeveloped gently rolling terrain. The channel has two major road 

crossings, County Road 650 South and Hospital Road, and a 

U.S. Government railroad crossing. 
Introduction 3

JOHNSON

COUNTY

BARTHOLOMEW

COUNTY

SHELBY

COUNTY

BROWN COUNTY

86°04' 86°00' 85°56'

39°24'

39°20'

39°16'

Driftwood

Big Blue River

Sugar

Pisgah

Lake

Nineve Creek

Creek

Muddy Branch Creek

River

Study

area

INDIANA

0 1 2 MILES

0 1 2 KILOMETERS

EXPLANATION

USGS Streamgage and number

 

Limit of study area

Interstate route marker

U.S. route marker

State route marker

Streams in study area

Flow arrow—Indicates

direction of water flow

03363000

Camp Atterbury boundary

03363000

03362500

County boundary

65

31

252

252

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/ 

Taylorsville

Corn Brook

Edinburgh

Camp Atterbury

US GOVERMENT RAILROAD BRIDGE

RAILROAD ROAD

TANNEHILL ROAD 

RIVER ROAD

CR 650 S

MAUXFERRY ROAD

CR 800 S/HOSPITAL ROAD

CR 500 N 

65

65

31

31

W. LOWELL ROAD

COUNTY LINE ROAD 

HENDRICKS FORD

ROAD

MAUXFERRY ROAD

WEST OHIO RIDGE ROAD

MORTON ROAD

Hwy 31 bridge

Figure 1. Location of study reaches for the Driftwood River and Sugar Creek, and location of USGS streamgages.
4 Flood-Inundation Maps for the Driftwood River and Sugar Creek near Edinburgh, Indiana

Previous Studies 

A Flood Insurance Study (FIS) for Bartholomew County 

(Federal Emergency Management Agency, 1981) was completed by the Louisville District of the U.S. Army Corps of 

Engineers for the Federal Insurance Administration in August, 

1979. That study provided information on the 0.2, 1.0, 2.0, 

and 10 percent annual exceedance probability water-surface 

profiles and associated flood plain maps for the Driftwood 

River, East Fork White River, Flatrock River, and numerous 

creeks and tributaries. A revised FIS was completed for Johnson County in 2007 (Federal Emergency Management Agency, 

2007). That study provided information on the 0.2, 1.0, 2.0, 

and 10 percent annual exceedance probability water-surface 

profiles and associated flood plain maps for Sugar Creek, 

Big Blue River, and numerous creeks, ditches, and swales in 

Johnson County.

Constructing Water-Surface Profiles

The water-surface profiles used to produce the nine 

flood-inundation maps in this study were computed 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 using the 

steady-state flow computation option.

Hydrologic and Steady Flow Data

The study area hydrologic network consists of two 

streamgages (fig. 1; table 1). One of the gages, Sugar Creek, 

already existed; the other gage at Driftwood River had been 

discontinued in 1991 and was re-activated in 2011 with a continuous recorder and recording tipping-bucket rain gage. Water 

level (stage) is measured continuously at both of the sites. All 

water-surface elevations are referenced to 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. 

Data can be accessed at http://waterdata.usgs.gov/in/nwis/

current/?type=flow by clicking on the appropriate streamgage 

number.

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

a previous study, normal depth, or streamgage rating curve 

value), and peak discharge information. 

Topographic/Bathymetric Data

Channel cross sections were developed from USGS field 

surveys that were carried out in May of 2011. These cross sections provide detailed channel elevation data below the water 

surface and were collected using hydroacoustic instrumentation to measure depth and Differential Global Positioning 

System (DGPS) instrumentation to determine horizontal position. Light Detection and Ranging (LiDAR) data were 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. Two sets of LiDAR data were merged for this study. 

The LiDAR data for Camp Atterbury and Sugar Creek were 

originated by Indianapolis Mapping and Geographic Infrastructure System in 2010 (Greater Indianapolis Area Aerial 

Lidar Survey, 2010). The LiDAR data for the Driftwood River 

were originated from Aero-Metric, Inc., Sheboygan, Wisconsin, in 2010. 

Various manmade drainage structures (bridges and 

roadway embankments) 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, structural dimensions for six bridges were measured 

and surveyed in the field concurrently with the stream channel 

surveys. A detailed description of the methods used to acquire 

and process the topographic and bathymetric data can be 

found in Bales and others (2007). 

 Steamgage 

 name

Streamgage 

number

 Drainage 

 area 

 (mi2

)

 Latitude 

 (NAD27)

Longitude 

 (NAD27) Period of record

 Datum 

 of gage 

 (NAVD88) 

 Maximum recorded 

 flood elevation 

 (NAVD88) 

 and date

Driftwood River 

near Edinburgh, 

Indiana

 03363000 1,060 39°20'21" 85°59'11" July 1941 to 

September 

1991, and 

January 2011 

to present

 636.60 ft 653.57 ft March 6, 1963

(corresponds to a stage of 

16.97 ft)

Sugar Creek near 

Edinburgh, 

Indiana

 03362500 474 39°21'39" 85°59'51" April 1943 to 

present

 645.83 ft 665.06 ft June 7, 2008 

(corresponds to a stage of 

19.23 ft)

Table 1. USGS Streamgage information for sites near Edinburgh, Indiana.
Constructing Water-Surface Profiles 5

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. The initial values were adjusted as part of the 

calibration process. The n-values for the main channel of the 

Driftwood River range from 0.035 to 0.044, and n-values for 

overbanks range from 0.045 to 0.12. For the main channel of 

Sugar Creek, n-values range from 0.031 to 0.035 and n-values 

for the overbanks range from 0.08 to 0.10. The n-value for the 

main channel of the Big Blue River was 0.038, and n-values 

for overbanks range from 0.08 to 0.09.

Model Calibration and Performance

The hydraulic model was calibrated to the stage-discharge 

relations at the USGS streamgage 03363000 Driftwood River 

near Edinburgh, Ind., and verified by comparing the stage 

values at the USGS streamgage 03362500 Sugar Creek near 

Edinburgh, Ind., based on estimated streamflow. Model calibration was accomplished by adjusting Manning’s n-values 

and loss coefficients until the results of the hydraulic computations closely agreed with the known water stage values. 

Differences between measured and simulated water-surface 

elevations were less than 0.16 ft for the Driftwood River gage 

(table 2). The differences between estimated and simulated 

water-surface elevations for the Sugar Creek gage were less 

than 0.25 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. However, due to the relatively large distance from the Driftwood River gage to the downstream extent 

of the study (10.3 mi), the accuracy of the maps may decrease 

toward the downstream end. No high-water marks were used 

for model validation since the marks from the 2008 flood were 

at a higher elevation than the highest profile used in the model. 

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 nine stages at 1-ft 

intervals between 9.00 ft and 17.00 ft as referenced to the 

USGS streamgage 03363000 Driftwood River near Edinburgh, 

Ind., corresponding to elevations of between 645.60 and 

653.60 ft NAVD88. 

Models on the Driftwood River were calibrated to produce the selected profile elevations at the USGS streamgage 

03363000 (table 4) and the estimated profile elevations at 

the Sugar Creek gage (table 5). Discharges at the mouth of 

Nineveh Creek and Muddy Branch Creek, tributaries to the 

Driftwood River, were determined by calculating cubic feet 

per second per square mile (CFSM) that corresponded to the 

measured discharges at the Driftwood River gage. Discharges 

at the Pisgah Lake tributary and at the upstream extent of 

Sugar Creek were also determined using CFSM. 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. 

Discharges on Sugar Creek and Big Blue River at the 

confluence with the Driftwood River were determined by 

calculating the relative percentage of drainage area to the 

combined drainage area of the Driftwood River at the gage. 

The drainage area for Sugar Creek is approximately 45 percent 

of the drainage area at the Driftwood River gage. The drainage area for Big Blue River is approximately 55 percent of the 

drainage area at the Driftwood River gage. It is important to 

note that the percentages of the two contributing basins is an 

estimate based on drainage areas, the actual discharge contributions depend on precipitation amounts in each basin. If a 

large amount of precipitation falls in only one of the contributing basins, the percentage of flow to the Driftwood River 

increases from that basin. Conversely, if little or no precipitation occurs in one of the basins there is little contribution to 

Driftwood River and the percentage decreases. Drainage areas 

Stage 

(ft)

Measured watersurface elevation 

(ft, NAVD88)

Modeled watersurface elevation 

(ft, NAVD88)

Elevation 

difference 

(ft)

9.00 645.60 645.51 0.09

10.00 646.60 646.60 0.00

11.00 647.60 647.47 0.13

12.00 648.60 648.59 0.01

13.00 649.60 649.54 0.06

14.00 650.60 650.45 0.15

15.00 651.60 651.48 0.12

16.00 652.60 652.73 -0.13

17.00 653.60 653.75 -0.15

Table 2. Comparison of measured water-surface elevations 

at USGS streamgage 03363000 Driftwood River near Edinburgh, 

Indiana, with water-surface elevations output from the hydraulic 

model. 

Table 3. Comparison of measured water-surface elevations at 

USGS streamgage 03362500 Sugar Creek near Edinburgh, Indiana, 

with water-surface elevations output from the hydraulic model.

Stage 

(ft)

Measured watersurface elevation 

(ft, NAVD88)

Modeled watersurface elevation 

(ft, NAVD88)

Elevation 

difference 

(ft)

7.62 653.45 653.40 0.05

8.19 654.02 654.03 -0.01

8.79 654.62 654.68 -0.06

9.65 655.48 655.64 -0.16

10.59 656.42 656.66 -0.24

11.70 657.53 657.48 0.05

13.10 658.93 658.85 0.08

15.03 660.86 660.65 0.21

16.42 662.25 662.36 -0.11
6 Flood-Inundation Maps for the Driftwood River and Sugar Creek near Edinburgh, Indiana

were calculated using a Web-based GIS application called 

Streamstats which can be accessed at http://water.usgs.gov/

osw/streamstats/indiana.html. Profile verification at the Sugar 

Creek gage used elevations that corresponded to 45 percent of 

the discharges at the Driftwood River gage. For example, the 

9.00 ft profile at the Driftwood River gage has a discharge of 

5,020 cubic feet per second (ft3

/s). Forty-five percent of 5,020 

ft3/s is 2,259 ft3/s. Using the current stage-discharge rating for 

the Sugar Creek gage, a discharge of 2,259 ft3/s corresponds to 

a stage of 7.62 or an elevation of 653.45 ft. This comparison 

method was used for each of the nine profiles. The modeled 

elevations at the Driftwood River gage were all within 0.16 

ft of the elevations corresponding to the estimated discharges 

at the gage. The modeled elevations at the Sugar Creek gage 

were all within 0.25 ft of the elevations corresponding to the 

estimated discharges at the gage.

Inundation Mapping

Flood-inundation maps were created for two stream 

reaches near USGS streamgages, one of which, the Driftwood 

River gage, has been designated as a NWS flood-forecast point 

(as of 2012). The maps were created in a GIS by combining 

the water-surface profiles and digital elevation model data. 

The digital elevation model (DEM) data were derived from 

merged LiDAR data sets with horizontal accuracy ranging 

from 1.0 to 3.2 ft and a vertical accuracy ranging from 0.18 

to 0.37 ft. The initial resolution of the DEM with 2.5-ft cell 

size was later modified to 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). 

 Stage in feet above gage datum at Driftwood River (reference datum 636.598 NAVD88) 

Location

Drainage 

area 

(mi2

)

9.00 

(745.60)

10.00 

(746.60)

11.00 

(747.60)

12.00 

(748.60)

13.00 

(749.60)

14.00 

(750.60)

15.00 

(751.60)

16.00 

(752.60)

17.00 

(753.60)

 Discharge (ft3/s)

Downstream extent of 

study area

 1,137 5,385 6,560 7,872 9,972 12,518 15,800 20,412 28,672 43,442

At mouth of Muddy 

Branch Creek 

confluence

 1,114 5,274 6,426 7,711 9,768 12,261 15,477 19,994 28,085 42,553

At mouth of Nineveh 

Creek confluence

 1,104 5,227 6,368 7,642 9,680 12,151 15,337 19,815 27,832 42,170

Streamgage number 

03363000

 1,060 5,020 6,116 7,339 9,297 11,670 14,730 19,030 26,730 40,500

Table 4. Stages and water-surface elevations, in feet, with corresponding discharge estimates at selected locations for the Driftwood 

River near Edinburgh, Indiana, for simulated water-surface profiles.

Table 5. Stages and water-surface elevations, in feet, with corresponding discharge estimates at selected locations for Sugar Creek 

near Edinburgh, Indiana, for simulated water-surface profiles.

 Stage in feet above gage datum at Driftwood River (reference datum 636.598 NAVD88) 

Location

Drainage 

area 

(mi2

)

7.60 

(653.40)

8.20 

(654.00)

8.80 

(654.60)

9.60 

(655.50)

10.60 

(656.40)

11.70 

(657.50)

13.10 

(658.90)

15.00 

(660.90)

16.40 

(662.20)

 Discharge (ft3/s)

Streamgage number 

03362500

 474.2 2,259 2,752 3,303 4,184 5,251 6,628 8,564 12,028 18,225

At mouth of Pisgah Lake 

tributary confluence

 8.9 2,230 2,718 3,261 4,131 5,185 6,544 8,450 11,876 17,994

Upstream extent of study 

area

 459.2 2,188 2,666 3,199 4,052 5,086 6,420 8,294 11,650 17,652
Inundation Mapping 7

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). The HEC–

GeoRAS results at the cross sections were adjusted 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, 

geo-referenced aerial photographs of the study area for each of 

the water-surface profiles that were generated by the hydraulic 

model.

Driftwood River and Sugar Creek, Indiana, 

Flood-Inundation Maps on the Internet

The flood-inundation maps and current study documentation are available online at the U.S. Geological Survey 

Publications Warehouse (http://pubs.usgs.gov/sim/2012/3210). 

Also, a Flood Inundation Mapping Science website has been 

established to provide a portal for USGS flood-inundation 

study information to the public at http://water.usgs.gov/osw/

flood_inundation/. That web portal has a link (http://wim.

usgs.gov/FIMI/FloodInundationMapper.html) to interactive online map libraries that can be downloaded in several 

commonly-used electronic file formats. In the latter link, each 

stream reach displayed contains further links to NWISWeb 

graphs of the current stage and streamflow at USGS 

streamgage 03363000 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. Roadways and bridges were closely 

reviewed and are shown as shaded (inundated and likely 

impassable) or not shaded (dry and passable) to facilitate 

emergency planning and use. However, buildings which are 

shaded do not reflect inundation but denote that bare earth 

surfaces in the vicinity of the buildings are inundated. When 

the water depth (as indicated in the Web Mapping Application 

by holding the cursor over an inundated area) in the vicinity 

of the building of interest exceeds that building’s height, the 

structure can be considered fully submerged.

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. 

Uncertainty Associated with 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 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 discharges and hydrologic conditions anticipated at the USGS 

streamgage(s). The hydraulic model reflects the land-cover 

characteristics and any bridge, dam, levee, or other hydraulic 

structures existing as of September 2011. Unique meteorological factors (timing and distribution of precipitation) may 

cause actual discharges along the modeled reach to vary from 

assumed during a flood, which may lead to deviations in 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 National Weather Service (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 or 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. 
8 Flood-Inundation Maps for the Driftwood River and Sugar Creek near Edinburgh, Indiana

Acknowledgments

The authors wish to thank the State and Federal agencies that have cooperated in the funding for the operation 

and maintenance of the gages used for this study, especially 

Camp Atterbury Joint Maneuver Training Center, Edinburgh, 

Indiana, the Indiana Department of Transportation, and the 

National Weather Service. 

Summary

A series of estimated flood-inundation maps were developed in cooperation with Camp Atterbury Joint Maneuver 

Training Center for the Driftwood River and Sugar Creek 

near Edinburgh, Indiana. In addition to maps showing areas of 

inundation, downloadable GIS raster files and KML map files 

showing the depth of flooded areas were produced. The estimated inundation areas are shaded to give a general indication 

of depth of water at any point.

These maps, available at a USGS Web portal, in conjunction with the real-time stage data from the USGS streamgage 

03363000 Driftwood River near Edinburgh, Ind., and National 

Weather Service flood-stage forecasts, can help to guide the 

general public in taking individual safety precautions and can 

provide Camp Atterbury officials with a tool to efficiently 

manage emergency flood operations and flood mitigation 

efforts. 

The maps were developed 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 (shaded) flood-inundation areas overlaid on highresolution, geo-referenced, aerial photographs of the study 

area for stream stages between 9.00 and 17.00 ft (645.60 and 

653.60 ft NAVD88) at USGS streamgage 03363000 Driftwood 

River near Edinburgh, Ind. 

References Cited

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

Order, Remote-sensing Image: Sheboygan, Wis., AeroMetric, 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 (FEMA), 1981, 

Flood Insurance Study, County of Bartholomew, Indiana, 

Community Number 180006. Washington, D.C., 68 p.

Federal Emergency Management Agency (FEMA), 2007, Flood 

Insurance Study, Johnson County, Indiana, Flood Insurance 

Study Number 18081CV000A. Washington D.C., 140 p.

Greater Indianapolis Area Aerial Lidar Survey, 2010, Remotesensing Image: Indianapolis Metropolitan Planning Organization (IndyMPO), Indianapolis Mapping and Geographic 

Infrastructure System (IMAGIS).

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

tools for support of HEC–RAS using ArcGIS, user’s manual: U.S. Army Corps of Engineers, Hydrologic Engineering 

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

army.mil/software/hec-ras/hec-georas_downloads.html 

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]. Availabe at http://www.hec.usace.army.

mil/software/hec-ras/hecras-download.html

U.S. Census Bureau, 2010, 2010 Census interactive population 

search IN-Edinburgh town: Washington, D.C., U.S. Census 

Bureau. Available at http://2010.census.gov/2010census/

popmap/ipmtext.php?fl=18:1820404

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.

Publishing support provided by: 

Denver Publishing Service Center

Manuscript approved for publication May 1, 2012

For more information concerning this publication, contact:

Director, Indiana Water Science Center

U.S. Geological Survey

5957 Lakeside Blvd.

Indianapolis, IN 46278

(317) 290-3333

Or visit the Indiana Water Science Center Web site at:

http://in.water.usgs.gov/

This report is available at: http://pubs.usgs.gov/sim/3210/.
Fowler and others— Flood-Inundation Maps for the Driftwood River and Sugar Creek near Edinburgh, Indiana—Scientific Investigations Map 3210