U.S. Department of the Interior

U.S. Geological Survey

Open-File Report 2007–1030

Prepared in cooperation with the City of Tarrant, Alabama

Simulation of Flood Profiles for Fivemile Creek 

at Tarrant, Alabama, 2006
Cover. May 7, 2003, flood in the City of Tarrant, Alabama. (Photographed by Fire Chief Billy Hewitt of the City of Tarrant and used 

with permission.)
Simulation of Flood Profiles for Fivemile Creek 

at Tarrant, Alabama, 2006

By K.G. Lee and T.S. Hedgecock

Prepared in cooperation with the City of Tarrant, Alabama

Open-File Report 2007–1030

U.S. Department of the Interior

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

DIRK KEMPTHORNE, Secretary

U.S. Geological Survey

Mark D. Myers, Director

U.S. Geological Survey, Reston, Virginia: 2007

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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:

Lee, K.G., and Hedgecock, T.S., 2007, Simulation of flood profiles for Fivemile Creek at Tarrant, Alabama, 2006: 

U.S. Geological Survey Open-File Report 2007–1030, 25 p.
iii

Contents

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

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

Purpose and Scope ..............................................................................................................................1

Description of the Study Reach..........................................................................................................1

Flood History..........................................................................................................................................3

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

Approach.........................................................................................................................................................3

Data Collection......................................................................................................................................3

Land-Use Determination......................................................................................................................7

Hydrologic Analyses.............................................................................................................................7

Hydraulic Modeling ..............................................................................................................................9

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

Simulation of Flood Flows.........................................................................................................10

Summary........................................................................................................................................................16

References Cited..........................................................................................................................................16

Appendix. Photographs Showing Locations of Cross Sections...........................................................17

Figures

1. Map showing Fivemile Creek study reach, Tarrant, Jefferson County, Alabama..............2

2–4. Photographs showing—

 2. May 7, 2003, flooding behind the City Hall in Tarrant, Alabama ....................................3

 3. May 7, 2003, flooding on State Highway 79 in Tarrant, Alabama ..................................4

 4. May 7, 2003, flooding at the City Hall in Tarrant, Alabama .............................................4

5–7. Maps showing—

 5. Approximate locations of cross sections A through G in the 

Fivemile Creek study reach..................................................................................................5

 6. Approximate locations of cross sections F through K in the 

Fivemile Creek study reach..................................................................................................6

 7. Fivemile Creek basin and associated development........................................................8

8–10. Graphs showing—

 8. Comparison of computed and actual flood profiles for the May 2003 flood..............12

 9. Computed flood profiles for current conditions .............................................................13

 10. Comparison of U.S. Geological Survey and Federal Emergency 

Management Agency computed 100-year flood profiles .............................................14
iv

Tables

1. Computed peak flows for the May 2003 flood..........................................................................7

2. Computed peak flows for current conditions...........................................................................9

3. Difference between observed and computed water-surface profiles 

for the May 2003 flood..................................................................................................................9

4. Computed flood profiles for current conditions.....................................................................10

5. Comparison of USGS and FEMA computed 100-year flood elevations .............................15

6. Average flood-plain depths for 100-year recurrence interval flood ..................................15

7. Maximum depth of overtopping for selected roadways and railways ..............................15

Conversion Factors and Datums

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 National Geodetic Vertical Datum of 1929 

(NGVD 29).

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

A one-dimensional step-backwater model was used to 

simulate flooding conditions for Fivemile Creek at Tarrant, 

Alabama. The 100-year flood stage published in the current 

flood insurance study for Tarrant by the Federal Emergency 

Management Agency was significantly exceeded by the 

March 2000 and May 2003 floods in this area. A peak flow 

of 14,100 cubic feet per second was computed by the U.S. 

Geological Survey for the May 2003 flood in the vicinity of 

Lawson Road. Using this estimated peak flow, flood-plain surveys with associated roughness coefficients, and the surveyed 

high-water profile for the May 2003 flood, a flow model was 

calibrated to closely match this known event. The calibrated 

model was then used to simulate flooding for the 10-, 50-, 

100-, and 500-year recurrence interval floods.

The results indicate that for the 100-year recurrence interval, the flood profile is about 2.5 feet higher, on average, than 

the profile published by the Federal Emergency Management 

Agency. The absolute maximum and minimum difference is 

6.80 feet and 0.67 foot, respectively. All water-surface elevations computed for the 100-year flood are higher than those 

published by the Federal Emergency Management Agency, 

except for cross section H. The results of this study provide 

the community with flood-profile information that can be used 

for existing flood-plain mitigation, future development, and 

safety plans for the city.

Introduction

Effective flood-plain management and planning depend 

on the accurate determination of flood profiles. In most 

cases, the application of a hydrologic and hydraulic model is 

necessary in the computation of flood profiles. Construction 

in flood-prone areas is a major concern of the City of Tarrant (formerly Tarrant City), Alabama. Tarrant is primarily 

an industrial town and is located in the Fivemile Creek basin. 

Since 1980, urban development has been based on existing 

profiles published by the Federal Emergency Management 

Agency (FEMA). Originally, these profiles were based on 

conditions reflective of 1979 (Federal Emergency Management Agency, 1980). In 1998, the FEMA flood profiles were 

revised in this reach and published in a later report (Federal 

Emergency Management Agency, 1999).

 Since the completion of the 1999 FEMA study, the basin 

has experienced increased urbanization affecting the flooding potential of Fivemile Creek. The U.S. Geological Survey 

(USGS), in cooperation with the City of Tarrant, revised the 

hydrology and flood profiles for a reach of Fivemile Creek 

that is about 20,000 feet (ft) long to accurately depict the 

current and future flooding potential. These flood profiles 

are designed to aid Tarrant’s engineers and planners with 

decisions concerning existing flood-plain mitigation, future 

development, and safety plans for the city.

Purpose and Scope

The objective of this report is to document the results of 

an investigation to determine the flood profiles for a reach of 

Fivemile Creek that is about 20,000 ft long. This reach extends 

from about 300 ft upstream from Lawson Road downstream to 

just below the L&N Railroad near Boyles Gap (fig. 1). Flood 

profiles were developed for the 10-, 50-, 100-, and 500-year 

floods using hydrologic and hydraulic models. Prior to the 

development of these profiles, the hydraulic model was calibrated to match the May 7, 2003, flood in order to apply the 

model to other flooding scenarios. The flood-profile information in this report can be used by the community for future 

planning and design purposes.

Description of the Study Reach

The City of Tarrant is located in north central Alabama, 

approximately 1.5 miles northeast of Birmingham, in Jefferson 

County, Alabama (fig. 1). The average slope of the channel 

in the study reach is 18.5 feet per mile (ft/mi). The stream 

flows in a southwesterly direction and has an average bankfull 

width of 85 ft with minimum and maximum widths of 50 and 

130 ft, respectively. Bankfull width is the width between the 

top of the left and right channel banks for a stream channel. 

The average flood-plain width is 1,000 ft and ranges from 

200 to 2,000 ft. The land cover of the reach is characterized 

by grassy fields and wooded areas with moderate vegetative 

undergrowth. The reach extends through areas of residential 

and industrial land use. These areas typically have minimal or 

maintained vegetative growth and areas of ineffective flow.

Simulation of Flood Profiles for Fivemile Creek 

at Tarrant, Alabama, 2006

By K.G. Lee and T.S. Hedgecock
LOCATION OF JEFFERSON

COUNTY IN ALABAMA

Fivemile Creek

Basin

0 1 2 MILES

0 1 2 3 KILOMETERS

Springdale Road

State Highway 79

Lawson Road

Ketona gage (USGS 02457000)

Lawson Road gage (USGS 02456980)

Study reach

Reach extent

L & N Railroad 

Alabama Power Company Road

L & N Railroad

EXPLANATION

33°36’

86°47’30” 86°45’

33°34’

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

Birmingham North, 1959, revised 1978; and Irondale, 1959,

revised 1978

Figure 1. Fivemile Creek study reach, Tarrant, Jefferson County, Alabama.

   Simulation of Flood Profiles for Fivemile Creek at Tarrant, Alabama, 2006
Flood History

Anthropogenic changes in the Fivemile Creek basin have 

substantially altered the hydrologic and hydraulic conditions 

of the basin. On March 10, 2000, and May 7, 2003, the flood 

stage at the Ketona gage on Fivemile Creek in Tarrant (USGS 

gage 02457000) (fig. 1) exceeded the published 100-year flood 

stage of 561.2 ft (Federal Emergency Management Agency, 

1999) by 2.8 ft and 4.6 ft, respectively. Both of these floods 

caused a considerable amount of damage to local residents and 

community businesses (Fire Chief Billy Hewitt, City of Tarrant, oral commun., 2004).

The study reach contains six hydraulic structures. Of the 

six structures, four were overtopped by the 2003 flood: Lawson Road, State Highway 79, Springdale Road, and the Alabama Power Company Road (fig. 1). Other roads within the 

city limits also were inundated (figs. 2–4), impeding the flow 

of traffic and causing substantial damage to local businesses.

Acknowledgments

Special thanks are given to Mayor Loxcil Tuck and Fire 

Chief Billy Hewitt of the City of Tarrant for their assistance 

in the initialization of this study. The assistance of Hillary 

Aten of the Cawaco Resource Conservation and Development 

Council is also greatly appreciated.

Approach

The creation of new flood profiles was accomplished 

through: (1) field data collection, (2) land-use (impervious cover) determinations, (3) hydrologic analyses, and 

(4) hydraulic modeling. Flood profiles were developed for 

the 10-, 50-, 100-, and 500-year floods using hydrologic and 

hydraulic models. Prior to the development of these profiles, 

the hydraulic model was calibrated to closely match the 

surveyed May 7, 2003, flood profile in order to increase the 

accuracy of the results provided by this study.

Data Collection

In order to accurately represent the stream-channel and 

flood-plain geometry of the reach, field surveys were conducted using an electronic total station. Eleven flood-plain 

cross sections were surveyed, and the geometry of all drainage 

structures and adjacent roadways was measured (figs. 5 and 6). 

The study reach included one culvert and five bridges. Eleven 

high-water marks from the May 7, 2003, flood also were 

surveyed by USGS personnel for model calibration purposes. 

These high-water marks define a 14,264-ft reach of the flood 

profile extending from river station 3,804 to 18,068. A river 

station was defined for each cross section, hydraulic structure, 

Figure 2. May 7, 2003, flooding behind the City Hall in Tarrant, Alabama.

Approach 
Figure 3. May 7, 2003, flooding on State Highway 79 in Tarrant, Alabama.

Figure 4. May 7, 2003, flooding at the City Hall in Tarrant, Alabama.

   Simulation of Flood Profiles for Fivemile Creek at Tarrant, Alabama, 2006
B

F

G

0 0.5 1 MILE

1 KILOMETER 0 0.5

C

D

A

E

EXPLANATION

Study reach

Cross-section location

A Cross-section identifier

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

Birmingham North, 1959, revised 1978

33°36’

86°47’ 86°46’

33°35’

Figure 5. Approximate locations of cross sections A through G in the Fivemile Creek study reach.

Approach   
J

K

F

I

H

G

0 0.5 1 MILE

1 KILOMETER 0 0.5

EXPLANATION

Study reach

Cross-section location

F Cross-section identifier

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

Birmingham North, 1959, revised 1978; and Irondale, 1959,

revised 1978

33°36’30”

86°46’ 86°44’

33°35’30”

Figure 6. Approximate locations of cross sections F through K in the Fivemile Creek study reach.

   Simulation of Flood Profiles for Fivemile Creek at Tarrant, Alabama, 2006
and high-water mark. River-stationing for the study reach is 

arbitrary and is referenced from the downstream-most cross 

section (section A), which is river station 0.

Roughness characteristics for the reach were assessed 

from field investigations. Manning’s roughness coefficients 

were selected to reflect current conditions and the conditions 

that existed during the 2003 flood. Manning’s roughness coefficients and geometric conditions were calibrated to provide 

the best match to the surveyed 2003 flood profile. These 

hydraulic parameters were then adjusted slightly to reflect 

current conditions. Manning’s roughness coefficients ranged 

from 0.05 to 0.065 for the channel and from 0.04 to 0.15 for 

the overbank areas. Photographs of the cross sections and the 

surrounding area are included in the Appendix as figures A1 

through A13.

Land-Use Determination

Industrial and residential growth have contributed to substantial changes in the hydrologic conditions in the Fivemile 

Creek basin since 1992. In order to determine the peak flows 

that reflect current conditions, land use and impervious cover 

for the basin were calculated using the most recent aerial 

photographs available for the reach. These photographs were 

supplemented with surveys and field reconnaissance in the 

newer sections of development. Impervious cover of a basin is 

the percentage of total drainage area that is covered by buildings or pavement that are impenetrable by infiltration from 

rainfall. The percentage of impervious cover is an indication 

of the degree of development or urban land use of a basin 

(Stamper, 1975).

Aerial photography from 2004 was made available by the 

City of Tarrant for the entire drainage basin and was used to 

measure impervious areas. The percentage of impervious area 

was calculated to be approximately 20 percent, and 5 percent 

was added to account for future growth. The resulting value 

of impervious area used in the hydrologic model, for estimated future conditions, was 25 percent. The majority of the 

Fivemile Creek basin has been developed (fig. 7); therefore, 

the percentage of impervious area used in the hydrologic 

model should adequately represent the urban land use for 

future years. Based on the 2001 National Land Cover Dataset 

(NLCD) (Multi-Resolution Land Characteristics Consortium, 

2006) and aerial photography (2004), the basin was estimated 

to be approximately 75 percent developed. The remaining 

25 percent is located in flood-plain and ridge areas and has a 

low probability of development.

As mentioned earlier, the most recent floods greatly 

exceeded the theoretical 100-year flood profile developed by 

FEMA (1999). The higher-than-expected flood stages may 

be attributed to the recent growth experienced in the basin. In 

order to understand the magnitude of the modifications the 

basin has experienced, the percentage of impervious area was 

calculated for 1992, based on the availability of the NLCD 

(U.S. Geological Survey, 1992). This analysis was performed 

for the drainage area upstream from Boyles Gap. The results of 

the calculations show that in 1992, the basin had about 12 percent impervious area, whereas the 2004 conditions show that 

the basin had about 20 percent impervious area. In a period of 

12 years, the percentage of impervious area almost doubled.

Hydrologic Analyses

Hydrologic analyses were conducted using the USGS 

urban regression equations and procedures outlined in “Synthesized Flood Frequency of Urban Streams in Alabama” (Olin 

and Bingham, 1982). In that study, a rainfall-runoff model was 

calibrated for 23 urban drainage basins in Alabama. The model, 

long-term rainfall data, and observed and synthetic evaporation 

data were used to synthesize a series of annual peak discharges 

for each site. The logarithms of the annual peaks were fitted to 

a Pearson Type III distribution to determine the frequency of 

peak discharge. Multiple regression equations were developed 

for estimating peak discharges having recurrence intervals 

of 2, 5, 10, 25, 50, and 100 years using data from 23 gaging 

stations in Alabama. Extrapolation techniques (Jennings and 

others, 1994) were used for the development of the 500-year 

recurrence interval peak-flow equation. The explanatory variables affecting peak discharge were drainage area and percentage of impervious area. Average standard errors of prediction 

for the relations in that study ranged from +24 to + 26 percent. Recurrence interval is the reciprocal of the probability 

of exceedance and is the average number of years between 

exceedances for a long period of record.

The May 7, 2003, flood brought a magnitude of flooding 

and destruction not previously seen in the City of Tarrant (Fire 

Chief Billy Hewitt, City of Tarrant, oral commun., 2004). The 

Ketona gage was destroyed prior to the peak. Additionally, the 

gage at Lawson Road (USGS gage 02456980) (fig. 1) had been 

deactivated in October 2001. Because of the lack of available streamflow data, an indirect discharge measurement was 

calculated at Lawson Road. An indirect discharge measurement 

of 14,100 cubic feet per second (ft3/s) was used to define the 

upper end of the stage-discharge relation at the Lawson Road 

gage (table 1). In order to transfer the computed peak from 

Lawson Road to the Ketona gage, the peak discharge transfer 

equation outlined in Atkins (1996) was applied. This method 

also was used to estimate peak flow at Boyles Gap.

Table 1. Computed peak flows for the May 2003 flood.

[ft,feet; mi2,

 square miles; ft3

/s, cubic feet per second]

River station

(ft) Location Drainage area(mi2)

Peak flow

(ft3/s)

259 Boyle’s Gap 28.4 18,800

13,168 Ketona Gage 23.9 16,700

17,718 Lawson Road 18.6 14,100

Approach 
0 1 2 MILES

EXPLANATION

Open waterDeveloped, open spaceDeveloped, low intensityDeveloped, medium intensityDeveloped, high inensityBarren land (rock/sand/clay)Deciduous forest

Evergreen forest

1 0 2 KILOMETERS

Mixed forestShrub/scrubGrassland/herbaceousPasture/hayCultivated cropsWoody wetlands

Streambed

Roads

Base from U.S. Geological Survey National Land Cover Data, fromLandsat-7 Thematic Mapper images 30-meter resolution, 2001

33°38’33°34’

86°48’ 86°38’

LOCATION OF JEFFERSON

COUNTY IN ALABAMA

Fivemile Creek

Basin

Figure 7. Fivemile Creek basin and associated development.

 Simulation of Flood Profiles for Fivemile Creek at Tarrant, Alabama, 2006
Using the drainage area, computed impervious area, 

and methods outlined by Olin and Bingham (1982), the peak 

flows (table 2) for each sub-reach were computed for selected 

recurrence intervals. These flows are applicable for current 

and future flooding potential. The May 7, 2003, peak flows are 

between the 100- and 500-year recurrence interval.

Hydraulic Modeling

The Hydrologic Engineering Center’s River Analysis 

System (HEC-RAS) (U.S. Army Corps of Engineers, 2002) was 

selected as the model to simulate flood flow in the Fivemile 

Creek basin. The HEC-RAS model was used to calculate the 

water-surface profiles for both gradually and rapidly varied 

steady flow. The gradually varied flow results of the model are 

based on the solution of the one-dimensional energy equation. The energy losses considered are those of friction and 

contraction/expansion. The frictional losses are computed using 

Manning’s equation. The contraction/expansion losses are computed as a function of the velocity head. In the areas of rapidly 

varied flow, the momentum equation is used by the model.

Model Calibration

Input data were entered and checked, and then the computational component of the model was used to simulate the 

May 2003 flood profile. The output showed that the simulated 

water-surface elevation was higher in some areas than the 

surveyed flood profile from the May 2003 flood. The methods used to calibrate the model to the known event were: the 

addition of interpolated cross sections, changes in Manning’s 

roughness coefficients, and the modification of some cross 

sections to reflect ineffective flow areas.

In order to have improved agreement between the simulated and actual flood profiles, additional cross sections were 

added. These sections were developed using the “interpolate 

between cross sections” function in HEC-RAS. After the sections were generated, they were checked for geometric accuracy. Roughness values were assigned to these sections based 

on aerial photography and field reconnaissance. The original 

input data also were modified to account for ineffective flow 

areas by manually blocking the appropriate areas of the cross 

section. Likewise, roughness values were adjusted slightly to 

improve the model’s agreement with the 2003 flood profile. 

The computed water-surface profile (table 3) was calibrated 

Table 2. Computed peak flows for current conditions. 

[ft, feet; mi2, square miles;ft3/s, cubic feet per second]

River station

(ft) Location Drainage area(mi2)

10-year peak flow

(ft3/s)

50-year peak flow

(ft3/s)

100-year peak flow

(ft3/s)

500-year peak flow

(ft3/s)

259 Boyle’s Gap 28.4 9,390 13,500 15,700 20,700

13,168 Ketona Gage 23.9 8,340 12,000 13,900 18,300

17,718 Lawson Road 18.6 7,020 10,100 11,700 15,400

Table 3. Difference between observed and computed water-surface profiles for the May 2003 flood.

[ft, feet; HEC-RAS, Hydrologic Engineering Center’s River Analysis System; see figures 5 and 6 for cross section locations]

River station

(ft)

Cross-section

identifier

Interpolated observed 

water-surface elevation

(ft)

HEC-RAS computed watersurface elevation

(ft)

Difference between observed and 

computed water-surface elevations

(ft)

5,206 D 537.22 537.38 +0.16

 6,863 E 542.00 542.10 +0.10

 8,692 F 544.37 544.13 –0.24

11,357 G 557.40 557.54 +0.14

13,315 Downstream side of 

State Highway 79

565.84 565.93 +0.09

14,986 I 567.88 568.09 +0.21

16,798 J 573.53 573.78 +0.25

17,618 100 ft downstream 

from Lawson 

Road

576.40 576.61 +0.21

18,068 K 580.50 580.70 +0.20

Approach 
within 0.25 ft of the observed 2003 flood profile. Points of 

comparison were based on water-surface elevations interpolated from the surveyed high-water profile, at cross sections 

above section C (fig. 8).

Simulation of Flood Flows

After the model was successfully calibrated to the 2003 

flood, the 10-, 50-, 100-, and 500-year flood flows were simulated. The resulting water-surface profiles reflect the flooding 

potential for the existing flood-plain conditions and account 

for future development (fig. 9). Water-surface elevations corresponding to these profiles also were calculated (table 4).

The results indicate that for the 100-year recurrence interval, the flood profile was about 2.5 ft higher, on average, than 

the profile published in the FEMA (1999) study. The absolute 

maximum and minimum difference was 6.80 ft and 0.67 ft, 

respectively. All water-surface elevations computed for the 

100-year flood were higher than those published by FEMA, 

except for cross section H (table 5, fig. 10).

The average flood-plain depth for the 100-year flood 

was computed for each cross section by dividing the effective 

flow area by the total width of flow. These depths ranged from 

2.4 ft at section H to 11.0 ft at section B (table 6). It should be 

noted that these are average values based on the flood-plain 

conditions on either side of the channel (overbank region). The 

actual depth varies throughout the flood plain based on the 

local ground-surface elevation. The elevations of the 100-year 

flood also were compared to the elevations of local roadways 

and railroads in Tarrant (table 7).

The average top width of flow for the study reach for the 

100-year flood was about 800 ft. This value varied from section to section based on the geometry of the flood plain. For 

instance, the flow at section A (fig. 5), located at Boyles Gap, 

had a top width of 150 ft. The maximum top width of flow of 

2,079 ft occurred just upstream from State Highway 79. This 

information is provided to show that the average value of top 

width of flow is averaged for the entire reach and not indicative of every cross section.

Table 4. Computed flood profiles for current conditions.

 [ft, feet; —, no data; see figures 5 and 6 for cross-section locations]

River station

(ft)

Cross-section

identifier

10-year 

water-­surface 

elevation

(ft)

50-year 

water-­surface 

elevation 

(ft)

100-year 

water-­surface 

elevation

(ft)

500-year 

water-­surface

 elevation

(ft)

0 Section A 515.84 518.43 519.68 522.24

259 — 516.32 518.58 519.64 521.71

260 L & N Railroad — — — —

589 — 518.61 522.15 525.68 534.45

661 — 520.84 525.07 528.36 536.70

1,077 Section B 521.41 525.32 528.50 536.74

2,080 — 522.57 525.45 528.75 536.86

3,030 — 528.92 530.92 531.26 537.17

3,130 — 529.35 531.43 531.94 537.24

3,131 Ala Power Co. Road — — — —

3,150 — 531.76 532.53 532.85 537.30

3,280 Section C 531.93 532.81 533.20 537.40

5,206 Section D 533.90 535.49 536.24 538.88

5,288 — 533.83 535.32 536.02 538.56

5,289 L & N Railroad — — — —

10 Simulation of Flood Profiles for Fivemile Creek at Tarrant, Alabama, 2006
River station

(ft)

Cross-section

identifier

10-year 

water-­surface 

elevation

(ft)

50-year 

water-­surface 

elevation 

(ft)

100-year 

water-­surface 

elevation

(ft)

500-year 

water-­surface

 elevation

(ft)

5,313 — 534.55 537.19 538.70 541.39

5,413 — 535.09 537.94 539.53 542.68

6,863 Section E 536.13 538.83 540.31 543.33

7,083 — 536.07 538.84 540.35 543.37

7,084 Springdale Road — — — —

7,111 — 536.84 538.90 540.54 543.44

7,203 — 537.56 539.36 540.78 543.54

7,952 — 538.36 540.06 541.30 543.86

8,692 Section F 541.35 542.46 543.10 544.91

10,000 — 548.63 549.90 550.32 550.90

11,357 Section G 554.82 556.29 556.83 557.94

13,168 Section H 560.79 562.36 562.98 564.20

13,315 — 561.51 563.19 564.05 566.37

13,316 State Highway 79 — — — —

13,430 — 561.84 564.44 565.93 567.49

13,745 — 563.25 565.85 566.26 567.72

14,986 Section I 565.17 566.75 567.18 568.44

15,898 — 565.25 566.99 567.47 568.86

16,798 Section J 571.22 572.36 572.99 574.07

17,218 — 572.41 573.75 574.41 575.62

17,618 — 573.93 575.21 575.83 576.97

17,718 — 573.78 574.78 575.23 575.92

17,719 Lawson Road — — — —

17,758 — 575.65 577.84 578.25 578.74

18,068 Section K 577.12 579.38 579.97 581.06

Table 4. Computed flood profiles for current conditions.­—Continued

 [ft, feet; —, no data; see figures 5 and 6 for cross-section locations]

Approach 11
480

–2,000 0 2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000 18,000 20,000

600580560540520500

EXPLANATION

RIVER STATION, IN FEET

ELEVATION IN FEET (NGVD)

USGS-surveyed streambedMay 2003 computed flood profile

May 2003 measured high- water marksCross section

Louisville and Nashville Railroad

Alabama Power Company Road

Louisville and Nashville Railroad

Springdale Road

State Highway 79

Lawson Road

A B C D E F G H I J K

Figure 8. Comparison of computed and actual flood profiles for the May 2003 flood. (See figures 5 and 6 for locations of cross sections.)

12 Simulation of Flood Profiles for Fivemile Creek at Tarrant, Alabama, 2006
Louisville and Nashville Railroad

Alabama Power Company Road

Louisville and Nashville Railroad

Springdale Road

State Highway 79

Lawson Road

600580560540520500480

ELEVATION IN FEET (NGVD)

–2,000 0 2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000 18,000 20,000

RIVER STATION, IN FEET

EXPLANATION

USGS-surveyed streambed10-year flood50-year flood100-year flood500-year flood

May 2003 measured high- water marksCross section

A B C D E F G H I J K

Figure 9. Computed flood profiles for current conditions. (See figures 5 and 6 for locations of cross sections.)

Approach 13
Louisville and Nashville Railroad

Alabama Power Company Road

Louisville and Nashville Railroad

Springdale Road

State Highway 79

Lawson Road

600580560540520500480

ELEVATION IN FEET (NGVD)

–2,000 0 2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000 18,000 20,000

RIVER STATION, IN FEET

EXPLANATION

USGS-surveyed streambedUSGS 100-year flood

FEMA 100-year flood

A B C D E F G H I J K

Figure 10. Comparison of U.S. Geological Survey and Federal Emergency Management Agency computed 100-year flood profiles. (See figures 5 and 6 for locations of cross sections.)

14 Simulation of Flood Profiles for Fivemile Creek at Tarrant, Alabama, 2006
Table 5. Comparison of USGS and FEMA computed 100-year flood elevations.

[ft, feet; see figures 5 and 6 for cross-section locations; USGS, U.S. Geological Survey; FEMA, Federal Emergency Management Agency]

River station (ft) Cross-section

identifier

USGS 100-year watersurface elevation (ft)FEMA 100-year watersurface elevation (ft) Difference (ft)

0 A 519.68 516.70 +2.98

1,077 B 528.50 521.70 +6.80

 3,280 C 533.20 529.20 +4.00

 5,206 D 536.24 533.00 +3.24

 6,863 E 540.31 538.20 +2.11

 8,692 F 543.10 539.80 +3.30

11,357 G 556.83 554.60 +2.23

13,168 H 562.98 563.90 –0.92

14,986 I 567.18 566.50 +0.68

16,798 J 572.99 570.10 +2.89

18,068 K 579.97 579.30 +0.67

Table 6. Average flood-plain depths for 100-year recurrence interval flood.

[ft, feet; see figures 5 and 6 for cross-section locations]

River station (ft) Cross-section

identifier

100-year water surface 

elevation (ft)

Average hydraulic 

depth (ft)

0 A 519.68 9.2

1,077 B 528.50 11.0

3,280 C 533.20 3.8

5,206 D 536.24 8.0

6,863 E 540.31 6.7

8,692 F 543.10 3.9

11,357 G 556.83 3.3

13,168 H 562.98 2.4

14,986 I 567.18 7.0

16,798 J 572.99 5.5

18,068 K 579.97 4.3

Table 7. Maximum depth of overtopping for selected roadways and railways.

[ft, feet; —, no data]

River station (ft) Roadway crossing in vicinity of bridge 100-year water-surface 

elevation (ft)

Maximum depth of 

overtopping (ft)

 260 L & N Railroad 525.68 —

 3,131 Alabama Power Company Road 532.85 3.2

 5,289 L & N Railroad 538.70 —

 7,084 Springdale Road 540.54 3.5

13,316 State Highway 79 Southbound Lane 565.93 2.1

13,316 State Highway 79 Northbound Lane 565.93 5.4

17,719 Lawson Road 578.25 0.8

Approach 15
Summary

A one-dimensional step-backwater model was used to 

simulate flooding conditions for Fivemile Creek at Tarrant, 

Alabama. The results of this study provide the community 

with flood-profile information that can be used for existing 

flood-plain mitigation, future development, and safety plans 

for the city. Land use and impervious cover for the basin were 

calculated using the most recent (2004) aerial photographs 

available for the reach and the National Land Cover Dataset 

for 1992 and 2001. The results of the calculations show that in 

1992, the basin had about 12 percent impervious area, whereas 

the 2004 conditions show that the basin had about 20 percent 

impervious area. In a 12-year period, the percentage of impervious area almost doubled.

Using data collected by the USGS from the May 2003 

flood, a flow model was calibrated to match (within 0.25 ft) 

the recorded event. The calibrated model then was used to 

simulate flooding for the 10-, 50-, 100-, and 500-year recurrence interval floods. The results indicate that for the 100-year 

recurrence interval, the flood profile was about 2.5 ft higher, 

on average, than the profile published by the Federal Emergency Management Agency (FEMA) in 1999. The absolute 

maximum and minimum difference was 6.80 ft and 0.67 ft, 

respectively. All water-surface elevations computed for the 

100-year flood were higher than those published by FEMA, 

except for cross section H.

 The average flood-plain depth was computed for each 

cross section based on the effective flow area and the total 

width of flow for the 100-year flood. These depths ranged 

from 2.4 ft at section H to 11.0 ft at section B. The results 

indicate that for the 100-year recurrence interval, overtopping 

would occur at the Alabama Power Company Road, Springdale Road, State Highway 79, and Lawson Road. The average 

top width of flow at a given section in the study reach for the 

100-year flood was about 800 ft. Top widths of flow in the 

study reach ranged from about 150 ft at section A to 2,079 ft 

just upstream from State Highway 79.

References Cited

Atkins, J.B., 1996, Magnitude and frequency of floods in Alabama: U.S. Geological Survey Water-Resources Investigations Report 95–4199, 234 p.

Federal Emergency Management Agency, 1980, Flood insurance study­—Tarrant City, Jefferson County, Alabama: 

Federal Emergency Management Agency, 18 p.

Federal Emergency Management Agency, 1999, Flood insurance study—Jefferson County, Alabama and incorporated 

areas: Federal Emergency Management Agency, 105 p.

Jennings, M.E., Thomas, W.O., Jr., and Riggs, H.C., 1994, 

National summary of U.S. Geological Survey regional 

regression equations for estimating magnitude and frequency of floods for ungaged sites, 1993: U.S. Geological 

Survey Water-Resources Investigations Report 94–4002, 

196 p.

Multi-Resolution Land Characteristics Consortium, 2006, 

National Land Cover Database 2001, accessed July 19, 

2006, at http://www.mrlc.gov/mrlc2k_nlcd.asp

Olin, D.A., and Bingham, R.H., 1982, Synthesized flood 

frequency of urban streams in Alabama: U.S. Geological 

Survey Water-Resources Investigations Report 82-683, 23 p.

Stamper, W.G., 1975, Flood mapping in Charlotte and 

Meklenburg County, North Carolina: U.S. Geological Survey Open-File Report, 22 p.

U.S. Army Corps of Engineers, 2002, HEC-RAS river analysis 

system users’ manual, version 3.1: U.S. Army Corps of 

Engineers, 420 p.

U.S. Geological Survey, 1992, National Land Cover Dataset 

1992, accessed December 1, 2005, at http://landcover.usgs.

gov/natllandcover.php

16 Simulation of Flood Profiles for Fivemile Creek at Tarrant, Alabama, 2006
Appendix. Photographs Showing Locations 

of Cross Sections

Figure A1. Cross section A, outlet of the box culvert at the L & N Railroad in Tarrant, Alabama. 

(See figure 5 for location.)

Figure A2. Downstream view of cross section B, in Tarrant, Alabama. (See figure 5 for location.)

Appendix 19
Figure A3. Upstream view of the Alabama Power Company Bridge, in Tarrant, Alabama. 

(See figure 5 for location.)

Figure A4. Upstream view of cross section C, in Tarrant, Alabama. (See figure 5 for location.)

20 Simulation of Flood Profiles for Fivemile Creek at Tarrant, Alabama, 2006
Figure A5. Downstream view of cross section D, in Tarrant, Alabama. (See figure 5 for location.)

Figure A6. Upstream view of the Railroad Bridge, in the vicinity of cross section D, 

in Tarrant, Alabama. (See figure 5 for location.)

Appendix 21
Figure A7. Downstream view of cross section E, in Tarrant, Alabama. (See figure 5 for location.)

Figure A8. West overbank of cross section F, in Tarrant, Alabama. (See figure 5 for location.)

22 Simulation of Flood Profiles for Fivemile Creek at Tarrant, Alabama, 2006
Figure A9. Downstream view of cross section H, in Tarrant, Alabama. (See figure 6 for location.)

Figure A10. Upstream view of the State Highway 79 Bridge, in Tarrant, Alabama. 

(See figure 6 for location.)

Appendix 23
Figure A11. Downstream view of cross section I, in Tarrant, Alabama. (See figure 6 for location.)

Figure A12. Upstream view of cross section J, in Tarrant, Alabama. (See figure 6 for location.)

24 Simulation of Flood Profiles for Fivemile Creek at Tarrant, Alabama, 2006
Figure A13. Downstream view of cross section K, in Tarrant, Alabama. (See figure 6 for location.)

Appendix 25



Lee and Hedgecock—Simulation of Flood Profiles for Fivemile Creek at Tarrant, Alabama, 2006—Open-File Report 2007–1030

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