Figure 2. Location of data-collection sites and recorded maximum surge elevation.

Figure 1. Path of Hurricane Rita, September 22-24, 2005, and monitored area in southwestern 

Louisiana and southeastern Texas.

TEXAS

LOUISIANA

ARKANSAS

MISSISSIPPI

ALABAMA

Gulf of Mexico

Monitored Area

09-22-05 4 a.m.

09-23-05 1 a.m.

09-23-05 10 p.m.

09-24-05 10 a.m.

FLORIDA

N

Hurricane Rita satellite imagery obtained from the National Aeronautics and Space 

Administration (2006).

TEXAS

LOUISIANA

Lake Charles Lafayette

Port

Arthur

Beaumont

- Water-level sensor

(9.4)

(7.5)

(10.6) (14.9)

(13.8) (13.3)

(11.2)

(5.0) (6.9)

(7.4)

(10.8)

(14.8) (14.7)

(8.9)

(8.0)

(9.4)

B15b

B12

B10

B19a B20

LC4

LC3

B1 B19b

LC12

LC13 LC11

LC9

LC7

LC6a

LC5

LC8b

LA3

LA12 LA11

LC2a

LC2b

LC6b

G u l f o f M e x i c o - Barometric-pressure sensor

- Maximum surge elevation (feet above NAVD 88)

LC10 LC8a

- Co-located barometric and water-level sensor

Abbeville (3.9) (4.2)

(4.5)

LA8 LA7

LA2

(8.7)

LA10 (6.6)

(10.7) LA9

LA9b

(10.1)

(9.5)

LF5

LF3

Sabine

Pass

165

167

96

90

49

27

10

82

82

14

27

27

Cameron

Intracoastal

City

10

Orange

Sabine Lake

Calcasieu Lake Grand Lake

White Lake

Vermilion

Lake

0 >30 - Land-surface elevation (feet above NAVD 88)

N

0 10 20 Kilometers

0 10 20 Miles

930 00’ 940

 00’

290 50’

U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2006–3136

December 2006

Monitoring Inland Storm Surge and Flooding from 

Hurricane Rita

Printed on recycled paper

Preventing flood hazards from 

becoming human disasters requires 

an understanding of the relative risks 

floods pose to specific communities 

and knowledge of the processes by 

which flood waters arise, converge, 

and abate. Such understanding can 

lead to improvements in the design 

of levees, dams, bridges, and other 

infrastructure; aid the delineation of 

flood plain boundaries and evacuation 

routes; and serve as the basis for wise 

land-use planning.

Historically, study of coastal 

storm-induced surge was based on 

analysis of flood evidence such as 

structural damage, vegetative damage, 

debris piles, high-water marks, and 

eye-witness accounts. However, 

these sources rarely provide useful 

information about the timing of the 

inundation, nor do they facilitate 

reconstruction of the various flow 

paths by which surge waters penetrate 

inland areas, or provide information 

to assess natural or man-made factors, 

which may affect flooding.

In response to these needs, the 

U.S. Geological Survey (USGS) 

designed and developed an 

experimental monitoring network 

of pressure transducers (sensors) 

to document the timing, extent, 

and magnitude of hurricane storm 

surge. The network was deployed 

to areas of southwestern Louisiana 

and southeastern Texas (figs. 1 and 

2) in the hours preceding landfall of 

Hurricane Rita in September 2005. 
Figure 3. Sensor used to collect water-level and 

barometric-pressure data.

E

l

e

v

a

t

i

o

n

i

n

F

e

e

t

23 24 25 26 27 28 29

September, 2005

-1.0

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

11.0

12.0

13.0

14.0

15.0

13

13.2

13.4

13.6

13.8

14

14.2

14.4

14.6

14.8

15

Barometric pressure

Lowest recordable elevation

Sensor water-level elevation

USGS stream gage 08012150 water-level elevation

Tape down elevation

16.0

15.0

14.0

13.0

12.0

11.0

10.0

9.0

8.0

7.0

6.0

5.0

4.0

3.0

2.0

1.0

0.0

-1.0

14.4

15.0

14.8

14.6

14.2

14.0

13.8

13.6

13.4

13.2

13.0

23 24 25 26 27 28 29

SEPTEMBER 2005

BAROMETRIC PRESSURE, IN POUNDS PER SQUARE INCH

b a Water-level sensor (a) placed near USGS coastal-streamgage (b) track together during surge inundation

WATER-LEVEL ELEVATION, IN FEET ABOVE NAVD 88

Figure 5. Hurricane Rita surge data at site LA2 west of Lafayette, Louisiana.

The resulting water-level/barometricpressure and related high-water mark 

data are described in USGS Data 

Series 220 and are available on the 

Internet at

 http://pubs.usgs.gov/ds/2006/220/

Monitoring Storm Surge

As Hurricane Rita approached 

the coast, sensor sites were selected 

based on storm-surge forecasts, the 

location and accessibility of piers 

and bridges, and local topography. 

Sensors were deployed at 33 sites 

from September 22-23, 2005, along 

selected waterways and in coastal 

marshes from Sabine Pass, Tex., to 

Lafayette, La., at distances ranging 

from a few hundred feet from the 

coast to approximately 30 miles 

inland. Sensors (fig. 3) were 

programmed to measure and record 

date and time, temperature, and 

pressure every 30 seconds during the 

storm and for several days afterward. 

Sensor housings were fabricated of 

1.25-inch diameter by 18-inch-long 

metal pipes and were deployed by 

strapping to permanent objects, such 

as piers and power poles (fig. 4A). 

Co-located sensors recorded water 

level and barometric pressure at 

7 selected sites, and individual sensors recorded water levels at 17 sites 

and barometric pressure at 9 sites. 

Figure 4. U.S. Geological Survey employees: (A) documenting site conditions during sensor 

recovery, (B) establishing a reference mark during sensor deployment, and (C) measuring the 

distance between the temporary reference mark and the sensor measuring point.

After the storm, the sensors 

(minus one that was destroyed) were 

recovered and the data downloaded 

and processed. Water-level data were 

corrected for changes in barometric 

pressure using data from a co-located 

or nearby barometric-pressure sensor. 

Water-level data also were corrected 

for salinity (water density). Corrections for salinity were based upon the 

location of the sensor in proximity to 

B C

A

the coast, as either saltwater (density 

of 64.0 lbs/ft3 [pounds per cubic 

foot]), brackish water (density of 

63.1, lbs/ft3), or freshwater (density of 

62.4, lbs/ft3).

To convert the water-level 

data from all the sensor sites to a 

common datum, temporary reference 

marks (fig. 4B) were established on 

permanent objects near each waterlevel sensor. Differential levels and 

graduated tapes (fig. 4C) were then 

used to relate the relative elevation of 

the temporary reference marks to that 

of the sensors, available high-water 

marks, and to the level of the water at 

the time the sensor was removed. 

Global Positioning System 

(GPS) equipment and techniques 

were used to determine the elevation 

of the temporary benchmarks. The 
23 24 25 26 27 28 29

September, 2005

-1.0

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

11.0

12.0

13.0

14.0

15.0

16.0

13.0

13.2

13.4

13.6

13.8

14.0

14.2

14.4

14.6

14.8

15.0

Barometric pressure

Lowest recordable elevation

Water-level elevation

High-water mark elevation

16.0

15.0

14.0

13.0

12.0

11.0

10.0

9.0

8.0

7.0

6.0

5.0

4.0

3.0

2.0

1.0

0.0

-1.0

14.4

15.0

14.8

14.6

14.0

13.8

13.6

13.4

13.2

13.0

23 24 25 26 27 28 29

SEPTEMBER 2005

High-water mark

BAROMETRIC PRESSURE, IN POUNDS PER SQUARE INCH

14.2

WATER-LEVEL ELEVATION, IN FEET ABOVE NAVD 88

Figure 6. Hurricane Rita surge data at site LA9b near Intracoastal City, Louisiana.

23 24 25 26 27 28 29

September, 2005

-1.0

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

11.0

12.0

13.0

14.0

15.0

16.0

13.0

13.2

13.4

13.6

13.8

14.0

14.2

14.4

14.6

14.8

15.0

Barometric pressure

Lowest recordable elevation

Water-level elevation

High-water mark elevation

BAROMETRIC PRESSURE, IN POUNDS PER SQUARE

WA

INCH

TER-LEVEL ELEVATION, IN FEET ABOVE NAVD 88

16.0

15.0

14.0

13.0

12.0

11.0

10.0

9.0

8.0

7.0

6.0

5.0

4.0

3.0

2.0

1.0

0.0

-1.0

14.4

15.0

14.8

14.6

14.2

14.0

13.8

13.6

13.4

13.2

13.0

23 24 25 26 27 28 29

SEPTEMBER 2005

High-water mark

Figure 7. Hurricane Rita surge data at site LC8a in Cameron, Louisiana.

GPS data were processed using 2 

first-order benchmarks and 6 National 

Geodetic Survey continuously 

operating reference stations (CORS) 

(National Geodetic Survey, 2006a) 

with Ashtech Solutions software 

(Ashtech Precision Products, 1999).

Quality Assurance

Quality-assurance procedures 

were used at selected sites to assess 

the variability and confirm the 

accuracy of the recorded water-level 

data. These procedures consisted of 

comparing water levels recorded by 

sensors to (1) water levels recorded 

by co-located sensors, (2) water 

levels recorded by nearby established 

USGS streamgages, (3) water-surface 

elevation of the water from which the 

sensor was recovered, and (4) field 

observed high-water mark elevations. 

Water levels recorded by the sensors 

at sites LF3 and LA7 were similar to 

water levels recorded by co-located 

sensors, and water levels recorded by 

the sensors at sites LA2 (fig. 5) and 

LA8 closely matched water levels 

recorded by USGS streamgages.

Water-level data were compared 

to the water-surface elevations of the 

water from which the sensors were 

recovered at seven sites: LA2 (fig. 5), 

LA3, LA9, LC2a, LF3, LC5, and 

LC8b. The data from the sensors 

matched the water-surface elevations 

within + 0.1 foot at all seven sites. 

The highest water levels 

recorded at seven sites, including 

LA9b (fig. 6), LA12, LC2b, LC5, 

LC7, LC8a (fig. 7), and LF5, were 

compared to the elevation of the 

nearest high-water mark. In general, 

the highest water levels recorded 

by sensors were similar to nearby 

high-water marks rated as excellent; 

however, the highest water levels 

recorded consistently were higher 

than high-water marks rated as 

good, fair, or poor. For example, the 

highest recorded water level near 

site LA9b (fig. 6) was approximately 

0.2 foot higher than the nearby highwater mark rated as excellent, and 

the highest recorded water level near 

site LC8a (fig. 7) was approximately 

1 foot higher than the nearby highwater mark rated as good.

Storm Surge And Flooding

In general, the highest surge 

elevations were recorded near the 

coast, and lower elevations were 

in excess of 5 feet per hour at many 

locations. Flooding at some locations 

near Interstate 10, such as sites LA3 

and LA2, was increased by river 

flows in addition to storm surge. 

The storm-surge data indicate the 

timing of flood waters as Hurricane 

Rita moved across the coast and 

inland. Approximate visualizations 

of these events can be created by 

interpolating water-level data between 

sensor locations and overlaying the 

results onto a digital-elevation model. 

For example, on September 24, 2005, 

3:00 a.m., a flood wave (dark red 

recorded inland through the approximate latitude of Interstate 10 (fig. 2). 

Figures 5, 6, and 7 show water-level 

and barometric-pressure data before, 

during, and after landfall of Hurricane 

Rita. Analysis of these and the 

remaining data indicate that peak 

water levels over 14 feet above North 

American Vertical Datum of 1988 

(NAVD 88) occurred at Constance 

Beach (LC11), Creole (LA12), and 

Grand Chenier (LA11), La., about 

20, 48, and 54 miles respectively, east 

of Sabine Pass, Tex. (fig. 2). During 

the storm surge, water levels rose 
B15b

B12

B10

B19a B20

LC4 LC3

B19b

B1

LC12

LC13 LC11

LC9

LC7

LC6a

LC5

LC8b

LA3

LA12 LA11

LC2a

LC2b

LC6b LA8 LA7

LA2

LA10

LA9

LA9b

LF5

LF3

TEXAS

LOUISIANA

Lake Charles Lafayette

Port

Arthur

Beaumont

- Water-level sensor Gulf of Mexico

- Barometric-pressure sensor

LC8a

- Co-located barometric-pressure and water-level sensors

Abbeville

Sabine

Pass

165

167

96

90

49

27

10

82

82

14

27

27

Cameron

Intracoastal

City

10

Orange

>13

12

11

0

1

10

9

8

6

5

4

3

2

Storm-surge depth (feet)

September 24, 3:00 a.m.

7 30 10’0’’ o

0 >30 - Land-surface elevation (feet above NAVD 88)

0 10 20 Kilometers

0 10 20 Miles N

Figure 8. Simulation of surge from Hurricane Rita on September 24, 2005, 3:00 a.m., using water-level and barometric-pressure data from sensors 

(Dean Gesch, U.S. Geological Survey, written commun., 2006).

930 00’ 940 00’

290 50’

area in fig. 8) is shown inland of the 

coast and along Louisiana Highway 

82 from sites LC11, LC9, LC8a, 

LA12, and LA11 (Dean Gesch, U.S. 

Geological Survey, written commun., 

2006).

Maps also can be generated 

to display flood duration, times 

of surge arrival and retreat, and 

maximum depths. Overlaying that 

information on other visualizations 

of hurricane impact, such as beach 

erosion and housing damage, could 

ultimately enable scientists and 

engineers to better understand surge 

mechanisms and design more robust 

infrastructure. Future deployments 

may feature monitoring of salinity 

and may include real-time telemetry 

to help emergency officials respond 

when storm surge threatens coastal 

communities.

Acknowledgments

The authors wish to thank the 

following USGS personnel for their 

dedication and diligence in collecting, 

processing, and publishing data for 

this study: Wade H. Kress, Joe G. 

Beauchamp, Christopher L. Braun, 

Marcus O. Gary, Robin H. Gary, and 

Joseph Vrabel, Texas Water Science 

Center; Brenda K. Woodward, 

Nebraska Water Science Center; 

Christopher J. Rowden and Paul H. 

Rydlund, Missouri Water Science 

Center; and the employees of the 

Ruston Program Office, Louisiana 

Water Science Center.

Selected References

Ashtech Precision Products, 1999, 

Ashtech solution user’s guide: 

Santa Clara, Calif., Magellan 

Corporation, 170 p.

McGee, B.D., Goree, B.B., Tollett, 

R.W., Woodward, B.K., and Kress, 

W.H., 2006, Hurricane Rita surge 

data, southwestern Louisiana and 

southeastern Texas, September to 

November 2005: U.S. Geological 

Survey Data Series 220.

National Aeronautics and Space 

Administration, 2006, Life on 

Earth-Looking at Earth: accessed 

May 16, 2006, at URL 

http://www.nasa.gov/vision/earth/

lookingatearth/h2005_rita.html 

National Geodetic Survey, 2006a, 

National Geodetic Survey 

continuously operating reference 

stations (CORS): accessed May 16, 

2006, at URL 

http://www.ngs.noaa.gov/CORS/

National Geodetic Survey, 2006b, 

National Geodetic Survey datasheet 

retrieval page: accessed May 16, 

2006, at URL http://www.ngs.noaa.

gov/cgi-bin/datasheet.prl

National Oceanic and Atmospheric 

Administration, 2006, National 

Hurricane Center: Hurricane 

Preparedness, SLOSH model: 

accessed September 21, 2005, at 

URL http://www.nhc.noaa.gov/

HAW2/english/surge/slosh.shtml

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).

Any use of trade, product, or 

firm names in this report is for 

descriptive purposes only and does 

not imply endorsement by the U.S. 

Government.

By Benton D. McGee, Roland W. Tollett, 

and Robert R. Mason, Jr.

For additional information contact:

Director

U.S. Geological Survey

Louisiana Water Science Center

3535 S. Sherwood Forest Blvd., Suite 120

Baton Rouge, LA 70816

Telephone: (225) 298-5481

Fax: (225) 298-5490

Email: crdemas@usgs.gov

Internet Home Page: http://la.water.usgs.gov