Prepared in cooperation with the Federal Emergency Management Agency

Characterization of Peak Streamflows and Flood Inundation 

of Selected Areas in Southeastern Texas and Southwestern 

Louisiana from the August and September 2017 Flood 

Resulting from Hurricane Harvey

Scientific Investigations Report 2018–5070

U.S. Department of the Interior

U.S. Geological Survey
Front cover, Photograph showing the area where Townsen Boulevard intersects U.S. Highway 59, about 

0.65 mile southwest of USGS streamflow-gaging station 08069500, West Fork San Jacinto River near 

Humble, Texas, August 30, 2017. Perspective of the photo is looking downstream, and the right flood plain 

of the West Fork San Jacinto River is shown. Photograph courtesy of Steve Fitzgerald, Harris County 

Flood Control District, used with permission.

Back cover:

Upper left, Photograph showing Addicks Reservoir looking upstream from top of dam with outlet 

works and lake station (USGS 08073000, Addicks Reservoir near Addicks, TX), August 29, 2017. Addicks 

Reservoir is a flood-control reservoir for the City of Houston, and its spillway is located about 12 miles 

north of Sugar Land, Texas. Photograph by Robert Ellis, Hydrologic Technician with the U.S. Geological 

Survey Gulf Coast Texas Program Office in Houston, Texas.

Upper right, Photograph showing Addicks Reservoir looking upstream from top of dam with outlet 

works and lake station (USGS 08073000, Addicks Reservoir near Addicks, TX), April 6, 2018. Addicks 

Reservoir is a flood-control reservoir for the City of Houston, and its spillway is located about 12 miles 

north of Sugar Land, Texas. Photograph by Tom Pistillo, Hydrologic Technician with the U.S. Geological 

Survey Gulf Coast Texas Program Office in Houston, Texas.

Lower left, Photograph showing Brandon Cooper, Hydrologic Technician with the U.S. Geological 

Survey, flagging a debris line on a telephone pole approximately 14.3 feet above the ground and located 

about 245 feet east of the bridge on Keith Road over Boggy Creek, September 15, 2017. Photograph by 

Melissa Null, Hydrologist with the U.S. Geological Survey North Texas Program Office in Fort Worth, 

Texas.

Lower right, Photograph showing U.S. Geological Survey streamflow-gaging station 08072600, Buffalo 

Bayou at State Highway 6 near Addicks, Texas, looking south on State Highway 6, August 31, 2017. The 

streamflow-gaging station is located about 10.5 miles north of Sugar Land, Texas. Barker Reservoir, a 

flood-control reservoir for the City of Houston, is to the right in the photo, and streamflow consists of 

releases from the reservoir. Photograph by MacKenzie Mullins, Hydrologic Technician with the U.S. 

Geological Survey Gulf Coast Texas Program Office in Houston, Texas.
Characterization of Peak Streamflows 

and Flood Inundation of Selected Areas 

in Southeastern Texas and Southwestern 

Louisiana from the August and 

September 2017 Flood Resulting from 

Hurricane Harvey

By Kara M. Watson, Glenn R. Harwell, David S. Wallace, Toby L. Welborn, 

Victoria G. Stengel, and Jeremy S. McDowell

Prepared in cooperation with the Federal Emergency Management Agency

Scientific Investigations Report 2018–5070

U.S. Department of the Interior

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

RYAN K. ZINKE, Secretary

U.S. Geological Survey

James F. Reilly II, Director

U.S. Geological Survey, Reston, Virginia: 2018

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

resources, natural hazards, and the environment—visit https://www.usgs.gov or call 1–888–ASK–USGS.

For an overview of USGS information products, including maps, imagery, and publications, 

visit https://www.usgs.gov/pubprod/.

Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the 

U.S. Government.

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

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

Suggested citation:

Watson, K.M., Harwell, G.R., Wallace, D.S., Welborn, T.L., Stengel, V.G., and McDowell, J.S., 2018, Characterization 

of peak streamflows and flood inundation of selected areas in southeastern Texas and southwestern Louisiana 

from the August and September 2017 flood resulting from Hurricane Harvey: U.S. Geological Survey Scientific 

Investigations Report 2018–5070, 44 p., https://doi.org/10.3133/sir20185070. 

ISSN 2328-0328 (online)

Inundated areas shown should not be used for navigation, regulatory, permitting, or other legal purposes. The U.S. 

Geological Survey 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.
iii

Acknowledgments

The authors would like to thank the staff of the Texas Natural Resources Information System, 

the Federal Emergency Management Agency, and the U.S. Geological Survey (USGS) who 

provided the digital elevation data necessary to complete this assessment. A special thanks 

is extended to Claire DeVaughan, USGS National Map Liaison for Texas and Oklahoma, for 

identifying data resources and interagency contacts to acquire these data.

v

Contents

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

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

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

Purpose and Scope .............................................................................................................................7

Description of Study Area ..................................................................................................................7

Weather Conditions Before and During the Flood ..................................................................................7

Methods ..........................................................................................................................................................8

Collection of High-Water Mark Data ................................................................................................8

Flood-Inundation Mapping ...............................................................................................................11

Flood Exceedance Probabilities of Peak Streamflows ................................................................11

Estimated Magnitudes and Flood Exceedance Probabilities of Peak Streamflows ........................16

Flood-Inundation Maps ..............................................................................................................................16

Brazos River and Tributaries ............................................................................................................16

Neches River and Tributaries ..........................................................................................................19

Pine Island Bayou .....................................................................................................................19

Sabine River and Tributaries ............................................................................................................23

Big Cow Creek ...........................................................................................................................27

Cow Bayou .................................................................................................................................27

San Bernard River ..............................................................................................................................27

San Jacinto River and Tributaries ...................................................................................................33

Coastal Basins ....................................................................................................................................37

East Matagorda Bay Subbasin ...............................................................................................37

Peak Water-Surface Elevations for Coastal Areas .............................................................42

Flood Damages ............................................................................................................................................42

Summary .......................................................................................................................................................42

References Cited .........................................................................................................................................42

Figures

1. Map showing rainfall totals in southeastern Texas and southwestern Louisiana 

from August 25 through September 1, 2017, resulting from Hurricane Harvey and 

locations of physiographic sections and climate divisions ..................................................2

2. Map showing the locations of U.S. Geological Survey streamflow-gaging 

stations used to calculate annual exceedance probabilities and rainfall totals 

from August 25 through September 1, 2017, resulting from Hurricane Harvey .................4

3. Map showing locations of U.S. Geological Survey streamflow-gaging stations, 

selected cities and counties, parishes, and river basins within the study area in 

southeastern Texas and southwestern Louisiana ...............................................................12

4. Flood-inundation map of the upper reach of the Brazos River for the August 

and September 2017 Hurricane Harvey-related flood event in southeastern 

Texas and southwestern Louisiana ........................................................................................17

5. Flood-inundation map of the lower reach of the Brazos River for the August 

and September 2017 Hurricane Harvey-related flood event in southeastern 

Texas and southwestern Louisiana ........................................................................................18
vi

6. Flood-inundation map of the upper reach of the Neches River for the August 

and September 2017 Hurricane Harvey-related flood event in southeastern 

Texas and southwestern Louisiana ........................................................................................20

7. Flood-inundation map of the lower reach of the Neches River for the August 

and September 2017 Hurricane Harvey-related flood event in southeastern 

Texas and southwestern Louisiana ........................................................................................21

8. Flood-inundation map of Pine Island Bayou, a tributary to the Neches River, 

for the August and September 2017 Hurricane Harvey-related flood event in 

southeastern Texas and southwestern Louisiana ...............................................................22

9. Flood-inundation map of the upper reach of the Sabine River for the August 

and September 2017 Hurricane Harvey-related flood event in southeastern 

Texas and southwestern Louisiana ........................................................................................24

10. Flood-inundation map of the middle reach of the Sabine River for the August 

and September 2017 Hurricane Harvey-related flood event in southeastern 

Texas and southwestern Louisiana ........................................................................................25

11. Flood-inundation map of the lower reach of the Sabine River for the August 

and September 2017 Hurricane Harvey-related flood event in southeastern 

Texas and southwestern Louisiana ........................................................................................26

12. Flood-inundation map of Big Cow Creek, a tributary to the Sabine River, for 

the August and September 2017 Hurricane Harvey-related flood event in 

southeastern Texas and southwestern Louisiana ...............................................................28

13. Flood-inundation map of Cow Bayou, a tributary to the Sabine River, for the 

August and September 2017 Hurricane Harvey-related flood event in 

southeastern Texas and southwestern Louisiana ...............................................................29

14. Flood-inundation map of the upper reach of the San Bernard River for the 

August and September 2017 Hurricane Harvey-related flood event in 

southeastern Texas and southwestern Louisiana ...............................................................30

15. Flood-inundation map of the middle reach of the San Bernard River for the 

August and September 2017 Hurricane Harvey-related flood event in 

southeastern Texas and southwestern Louisiana ...............................................................31

16. Flood-inundation map of the lower reach of the San Bernard River for the 

August and September 2017 Hurricane Harvey-related flood event in 

southeastern Texas and southwestern Louisiana ...............................................................32

17. Flood-inundation map of the West Fork San Jacinto River and its tributaries for 

the August and September 2017 Hurricane Harvey-related flood event in 

southeastern Texas and southwestern Louisiana ...............................................................35

18. Flood-inundation map of the East Fork San Jacinto River and its tributaries for 

the August and September 2017 Hurricane Harvey-related flood event in 

southeastern Texas and southwestern Louisiana ...............................................................36

19. Flood-inundation map of Peyton Creek, Big Boggy Creek, and Little Boggy Creek 

for the August and September 2017 Hurricane Harvey-related flood event in 

southeastern Texas and southwestern Louisiana ...............................................................38

20. Flood-inundation map of the Tres Palacios River for the August and September 

2017 Hurricane Harvey-related flood event in southeastern Texas and 

southwestern Louisiana ...........................................................................................................39

21. Flood-inundation map of the East and West Carancahua Creeks and the Keller 

Creek for the August and September 2017 Hurricane Harvey-related flood event 

in southeastern Texas and southwestern Louisiana ...........................................................40

22. Flood-inundation map from coastal water-surface elevation data for the August 

and September 2017 Hurricane Harvey-related flood event in southeastern 

Texas and southwestern Louisiana ........................................................................................41
vii

Tables

1. Rainfall totals resulting from Hurricane Harvey reported at 38 National Oceanic 

and Atmospheric Administration meteorological stations and 2 Jefferson County 

Drainage District rain gages in southeastern Texas from August 25 through 

September 1, 2017 ........................................................................................................................3

2. U.S. Geological Survey streamflow-gaging stations in southeast Texas with at 

least 15 years of record, no large data gaps in the period of record, and a 2017 

annual peak streamflow ranking in the top five of all annual peaks for a given 

station that were used to calculate annual exceedance probabilities ..............................5

3. Peak gage heights, peak streamflows, and estimated annual exceedance 

probabilities for the August and September 2017 Hurricane Harvey-related flood 

event at 74 selected U.S. Geological Survey streamflow-gaging stations in 

southeastern Texas .....................................................................................................................9

4. Counties, parishes, waterbodies, reach lengths, and number of high-water 

marks used to generate flood-inundation maps ...................................................................13

5. Site identification number, station number, and expected peak streamflows for 

selected annual exceedance probabilities with 95 percent confidence intervals 

at 74 selected U.S. Geological Survey streamflow-gaging stations in 

southeastern Texas ...................................................................................................................14

Conversion Factors

U.S. customary units to International System of Units

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

inch (in.) 25.4 millimeter (mm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

square mile (mi2) 259.0 hectare (ha)

square mile (mi2) 2.590 square kilometer (km2) 

Flow rate

cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s)

mile per hour (mi/h) 1.609 kilometer per hour (km/h) 

Datum

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

(NAVD 88) and the National Geodetic Vertical Datum of 1929 (NGVD 29).

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

Elevation as used in this report, refers to distance above the vertical datum.
viii

Abbreviations

AEP annual exceedance probability

DEM digital elevation model

FEMA Federal Emergency Management Agency

GIS geographic information system

GPS Global Positioning System

HWM High-water mark

Lidar light detection and ranging

NOAA National Oceanic and Atmospheric Administration

NWS National Weather Service

STN Short-Term Network (USGS)

USGS U.S. Geological Survey
Characterization of Peak Streamflows and Flood 

Inundation of Selected Areas in Southeastern Texas 

and Southwestern Louisiana from the August and 

September 2017 Flood Resulting from Hurricane Harvey

By Kara M. Watson, Glenn R. Harwell, David S. Wallace, Toby L. Welborn, Victoria G. Stengel, and 

Jeremy S. McDowell

Abstract

Hurricane Harvey made landfall near Rockport, Texas, 

on August 25, 2017, as a Category 4 hurricane with wind 

gusts exceeding 150 miles per hour. As Harvey moved inland, 

the forward motion of the storm slowed down and produced 

tremendous rainfall amounts over southeastern Texas, with 

8-day rainfall amounts exceeding 60 inches in some locations, 

which is about 15 inches more than average annual amounts 

of rainfall for eastern Texas and the Texas coast. Historic 

flooding occurred in Texas as a result of the widespread, 

heavy rainfall; wind and flood damages were estimated to 

be $125 billion, and the storm resulted in at least 68 direct 

fatalities. 

In the immediate aftermath of the Harvey-related flood 

event, the U.S. Geological Survey (USGS) and the Federal 

Emergency Management Agency initiated a cooperative 

study to evaluate the magnitude of the flood, determine the 

probability of occurrence, and map the extent of the flood 

in Texas. Seventy-four USGS streamflow-gaging stations in 

Texas with at least 15 years of record and no large data gaps 

in the period of record had a 2017 annual peak streamflow 

related to Harvey ranking in the top five of all annual peaks 

for each given station. New peaks of record streamflow were 

recorded at 40 of the 74 USGS streamflow-gaging stations. 

The number of years of peak streamflow record for the 

74 analyzed streamflow-gaging stations ranged from 18 to 

105, with a mean number of 55 years. The annual exceedance 

probability estimates for the analyzed streamflow-gaging 

stations ranged from less than 0.2 to 14.0 percent. USGS field 

crews surveyed 2,123 high-water marks to obtain watersurface elevations, in feet above the North American Vertical 

Datum of 1988. In some locations, several water-surface 

elevations were averaged to obtain 1 water-surface elevation, 

resulting in 1,258 water-surface elevations. Some of these 

high-water marks were used, along with peak-stage data from 

USGS streamflow-gaging stations, to create 19 inundation 

maps to document the areal extent of the maximum depth of 

the flooding. Digital datasets of the inundation area, modeling 

boundary, water-depth rasters, and final map products are 

available from the USGS data release associated with this 

report (https://doi.org/10.5066/F7VH5N3N).

Introduction

On August 17, 2017, Hurricane Harvey (referred to 

hereinafter as Harvey) entered the Caribbean Sea as a tropical 

storm, but it became disorganized and was downgraded 

to a tropical wave as it entered the Gulf of Mexico on 

August 22 (National Oceanic and Atmospheric Administration 

[NOAA], 2018a). During the next 72 hours, however, Harvey 

intensified into a Category 4 hurricane and made landfall 

near Rockport, Texas, about 10:00 p.m. on August 25 with 

wind gusts exceeding 150 miles per hour (mi/h) (NOAA, 

2018b). As Harvey moved inland, the forward motion of 

the storm slowed down and produced tremendous rainfall 

amounts in southeastern Texas and southwestern Louisiana, 

with 8-day rainfall amounts exceeding 60 inches (in.) in some 

areas of Texas (Blake and Zelinsky, 2018; fig. 1; table 1). 

Historic flooding accompanied by extensive wind damage 

occurred in Texas and Louisiana as a result of the widespread, 

heavy rainfall (NOAA, 2018c). In the immediate aftermath 

of the Harvey-related flood event, the U.S. Geological 

Survey (USGS) and the Federal Emergency Management 

Agency (FEMA) initiated a cooperative study to evaluate 

the magnitude of the flood, determine the probability of 

occurrence, and map the extent of the flood in selected river 

basins in Texas. For this study, flood-peak streamflow data 

that were recorded at 74 streamflow-gaging stations operated 

by the USGS in southeastern Texas were selected for analysis 

(fig. 2; table 2).
2 Characterization of Peak Streamflows and Flood Inundations from Hurricane Harvey, 2017

West Gulf Coastal Plain

Edwards Plateau

Central Texas

8

4

1

7

6 2

3

9

5

35

30

40

38

32

26

17 33

25

31

21

29

12

10

23

15

11

37

22

27

34

20

24

39

28

36

19

14

13

18

16

37

San Jose Island

East Texas

Upper Coast

TEXAS

LOUISIANA

ARKANSAS

Groves

Medina Houston

Victoria

Rockport

Galveston

Sugar

Land

Lake Jackson

Port Aransas Corpus Christi

Nederland

Beaumont

Rosenberg Texas City

Groves

Medina Houston

Victoria

Rockport

Galveston

Sugar

Land

Lake Jackson

Port Aransas Corpus Christi

Nederland

Beaumont

Rosenberg Texas City

Red River

Sabine River Sabine River

GULF OF MEXICO

Matagorda Bay

EXPLANATION

Physiographic section boundary, from

Fenneman (1946)

National Oceanic and Atmospheric

Administration meteorological station

and site identification number—Station

number listed in table 1

Contiguous United States (CONUS)

Climate Divisions, from National Oceanic

and Atmospheric Administration (2017)

Rainfall totals, in inches, from August 25

through September 1, 2017

0 to 1

1.1 to 5

5.1 to 10

10.1 to 15

15.1 to 20

20.1 to 25

25.1 to 30

30.1 to 35

35.1 to 40

40.1 to 45

45.1 to 54.26

Note: The record rainfall amounts of 60.58 and 

60.54 inches listed in table 1 are from 

Jefferson County Drainage District rain 

gages, which were probably not used by the 

National Weather Service to create the maps 

depicting rainfall amounts in the study area; 

to create maps of rainfall amounts, the 

National Weather Service averages rainfall 

over large areas, which could also account for 

discrepancies between the maximum rainfall 

amounts depicted in figs. 1–2 and individual 

point values exceeding 60 inches of rain listed 

in table 1.

100° 99° 98° 97° 96° 95° 94° 93°

33°

32°

31°

30°

29°

28°

Base modified from National Weather Service, Advanced Hydrologic Prediction Service

http://water.weather.gov/precip/download.php, accessed February 28, 2018

Albers Equal Area Projection, Texas Centric Mapping System

North American Datum of 1983 (2011)

0 50 100 MILES

0 50 100 KILOMETERS

Figure 1. Rainfall totals in southeastern Texas and southwestern Louisiana from August 25 through September 1, 2017, resulting from 

Hurricane Harvey and locations of physiographic sections and climate divisions.
Introduction 3

Table 1. Rainfall totals resulting from Hurricane Harvey reported at 38 National Oceanic and Atmospheric Administration 

meteorological stations and 2 Jefferson County Drainage District rain gages in southeastern Texas from August 25 through September 1, 

2017 (Blake and Zelinsky, 2018).

[N, north; S, south; E, east; W, west; I, Interstate]

Site identification 

number 

(fig. 1)

Station name1 County

Latitude 

(decimal 

degrees)

Longitude 

(decimal 

degrees)

Rainfall 

total 

(inches)2

3

1 Nederland 1.5 SW Jefferson 29.95 94.01 60.58

3

2 Groves 1.3 N Jefferson 29.96 93.92 60.54

3 Friendswood Galveston 29.50 95.20 56.00

4 Santa Fe 3 ENE Galveston 29.39 95.05 54.77

5 Friendswood Harris 29.75 95.57 54.00

6 Labelle Road Pevito Bayou Jefferson 29.96 94.17 53.82

7 League City 3 S Galveston 29.43 95.11 52.87

8 Webster 2 NW Harris 29.55 95.14 52.30

9 Ellington Field 2 E Harris 29.60 95.12 52.00

10 League City 4 S Galveston 29.42 95.11 51.62

11 Friendswood 2 NNW Brazoria 29.54 95.22 50.04

12 Liberty 2 WSW Liberty 30.06 94.82 49.39

13 Dayton 0.2 E Liberty 30.05 94.89 49.31

14 Fannett 1 NE Jefferson 29.93 94.24 49.25

15 Glenbrook Drive at Green Acres at Ditch 407 Jefferson 29.94 94.23 49.25

16 Beaumont 4 S Jefferson 30.02 94.14 49.06

17 State Highway 124 at Hillebrandt Bayou Jefferson 30.04 94.15 49.06

18 Clear Creek at I-45 Harris 29.51 95.12 48.20

19 Webster 2 S Galveston 29.50 95.12 48.20

20 Clear Lake Brazoria 29.56 95.39 48.14

21 Pine Ridge 4 NNW Hardin 30.30 94.40 42.60

22 East Fork of DB at Fairview Road Chambers 29.73 94.58 41.57

23 Greens Bayou at US 59 Harris 29.92 95.31 37.60

24 Carpenters Bayou at Wallisville Road Harris 29.81 95.16 37.44

25 Romayor/Trinity River Liberty 30.43 94.85 30.10

26 Vidor 7.2 N Orange 30.23 93.98 29.64

27 Cypress 3.2 ESE Harris 29.96 95.65 27.83

28 Brookshire Katy Drainage District at Morrison Road Waller 29.89 95.94 27.04

29 Magnolia 2.8 S Montgomery 30.17 95.76 26.93

30 Woodville 7.2 S Tyler 30.67 94.43 25.01

31 Pinehurst 0.4 SSE Montgomery 30.10 95.41 23.85

32 Wallis 1.1 NE Austin 29.64 96.05 21.83

33 Smithville 6.6 SE Fayette 29.95 97.07 21.72

34 Columbus 3.2 WSW Colorado 29.68 96.60 21.39

35 Zavalla 2.0 ESE Angelina 31.15 94.39 20.27

36 Brenham 9.9 N Washington 30.30 96.42 18.80

37 El Campo 4.9 SSE Wharton 29.13 96.26 15.16

38 West Columbia 1 ESE Brazoria 29.14 95.63 10.16

39 Carlos 3 NE Grimes 30.63 96.03 6.04

40 Willis 1 SW Montgomery 30.42 95.49 5.00

1

Station name taken directly from https://www.nhc.noaa.gov/data/tcr/AL092017_Harvey.pdf (Blake and Zelinsky, 2018).

2

Rainfall total from August 25 through September 1, 2017.

3

Jefferson County Drainage District rain gage.
4 Characterization of Peak Streamflows and Flood Inundations from Hurricane Harvey, 2017

Figure 2. The locations of U.S. Geological Survey streamflow-gaging stations used to calculate annual exceedance probabilities and 

rainfall totals from August 25 through September 1, 2017, resulting from Hurricane Harvey.

Groves

Houston

Victoria

Beaumont

Rosenberg

Galveston

Nederland

Texas City

Sugar Land

Lake Jackson

Groves

Houston

Victoria

Beaumont

Rosenberg

Galveston

Nederland

Texas City

Sugar Land

Lake Jackson

9

8

7

6

5

4

3

2

1

74

73

72

71

70

69 68

67

66

65

64

63

62

61

60

59

58

56 57

55

54 52 53

51

50 49

48

47

46

45

44 43

42

41

40 3839

37

36

35

34

33 32

31

30

29

28

27

26

25 24

23

22

21

20

19 18 17

16

15

14

13

12

11

10

LOUISIANA

TEXAS

74

97° 96° 95° 94°

31°

30°

29°

Sabine River Sabine River

GULF OF MEXICO

EXPLANATION

Rainfall totals, in inches, from August 25

through September 1, 2017

0 to 1

1.1 to 5

5.1 to 10

10.1 to 15

15.1 to 20

20.1 to 25

25.1 to 30

30.1 to 35

35.1 to 40

40.1 to 45

45.1 to 54.26

U.S. Geological Survey streamflow-gaging station

used to calculate annual exceedance probabilities

and associated site identification number—Station

number listed in table 2

Note: The record rainfall amounts of 60.58 and 60.54 inches 

listed in table 1 are from Jefferson County Drainage District 

rain gages, which were probably not used by the National 

Weather Service to create the maps depicting rainfall 

amounts in the study area; to create maps of rainfall 

amounts, the National Weather Service averages rainfall 

over large areas, which could also account for discrepancies 

between the maximum rainfall amounts depicted in figs. 1–2 

and individual point values exceeding 60 inches of rain listed 

in table 1.

0 25 50 MILES

0 25 50 KILOMETERS

Base modified from National Weather Service, Advanced 

Hydrologic Prediction Service 1:1,000,000 scale digital data

http://water.weather.gov/precip/download.php, accessed February 28, 2018

Albers Equal Area Projection, Texas Centric Mapping System

North American Datum of 1983 (2011)
Introduction 5

Table 2. U.S. Geological Survey streamflow-gaging stations in southeast Texas with at least 15 years of record, no large data gaps in 

the period of record, and a 2017 annual peak streamflow ranking in the top five of all annual peaks for a given station that were used to 

calculate annual exceedance probabilities.—Continued

[mi2, square miles]

Site 

identification 

number 

(fig. 2)

Station 

number Station name

Drainage 

area 

(mi2)

Latitude

(decimal 

degrees)

Longitude

(decimal 

degrees)

1 08026000 Sabine River near Burkeville, Texas 7,482 31.06408 93.51962

2 08028500 Sabine River near Bon Wier, Texas 8,229 30.74715 93.60851

3 08029500 Big Cow Creek near Newton, Texas 128 30.81889 93.78556

4 08030500 Sabine River near Ruliff, Texas 9,329 30.30382 93.74378

5 08031000 Cow Bayou near Mauriceville, Texas 83.3 30.18632 93.90851

6 08039100 Ayish Bayou near San Augustine, Texas 89.0 31.39630 94.15103

7 08040600 Neches River near Town Bluff, Texas 7,574 30.79104 94.15102

8 08041500 Village Creek near Kountze, Texas 860 30.39799 94.26352

9 08041700 Pine Island Bayou near Sour Lake, Texas 336 30.10605 94.33463

10 08065800 Bedias Creek near Madisonville, Texas 321 30.88472 95.77778

11 08066250 Trinity River near Goodrich, Texas 16,844 30.57215 94.94882

12 08066300 Menard Creek near Rye, Texas 152 30.48139 94.77972

13 08067000 Trinity River at Liberty, Texas 17,468 30.05772 94.81826

14 08067500 Cedar Bayou near Crosby, Texas 64.9 29.97272 94.98576

15 08067650 West Fork San Jacinto River below Lake Conroe near Conroe, Texas 451 30.34215 95.54300

16 08068000 West Fork San Jacinto River near Conroe, Texas 828 30.24466 95.45716

17 08068090 West Fork San Jacinto River above Lake Houston near Porter, Texas 962 30.08605 95.29993

18 08068275 Spring Creek near Tomball, Texas 186 30.11994 95.64606

19 08068325 Willow Creek near Tomball, Texas 41.0 30.10550 95.54661

20 08068390 Bear Branch at Research Boulevard, The Woodlands, Texas 15.4 30.19056 95.49111

21 08068400 Panther Branch at Gosling Road, The Woodlands, Texas 25.9 30.19194 95.48361

22 08068450 Panther Branch near Spring, Texas 34.5 30.13417 95.47750

23 08068500 Spring Creek near Spring, Texas 409 30.11050 95.43633

24 08068720 Cypress Creek at Katy-Hockley Road near Hockley, Texas 110 29.95022 95.80828

25 08068740 Cypress Creek at House-Hahl Road near Cypress, Texas 131 29.95911 95.71772

26 08068780 Little Cypress Creek near Cypress, Texas 41.0 30.01605 95.69745

27 08068800 Cypress Creek at Grant Road near Cypress, Texas 214 29.97356 95.59855

28 08068900 Cypress Creek at Stuebner-Airline Road near Westfield, Texas 248 30.00661 95.51189

29 08069000 Cypress Creek near Westfield, Texas 285 30.03578 95.42883

30 08070000 East Fork San Jacinto River near Cleveland, Texas 325 30.33660 95.10410

31 08070200 East Fork San Jacinto River near New Caney, Texas 388 30.14549 95.12438

32 08070500 Caney Creek near Splendora, Texas 105 30.25966 95.30244

33 08071000 Peach Creek at Splendora, Texas 117 30.23271 95.16827

34 08071280 Luce Bayou above Lake Houston near Huffman, Texas 218 30.10966 95.05993

35 08072300 Buffalo Bayou near Katy, Texas 63.3 29.74329 95.80690

36 08072730 Bear Creek near Barker, Texas 21.5 29.83078 95.68689

37 08072760 Langhan Creek at West Little York Road near Addicks, Texas 24.6 29.86694 95.64639

38 08073500 Buffalo Bayou near Addicks, Texas 277 29.76190 95.60578

39 08073600 Buffalo Bayou at West Belt Drive, Houston, Texas 290 29.76217 95.55772

Table 2. U.S. Geological Survey streamflow-gaging stations in southeast Texas with at least 15 years of record, no large data gaps in 

the period of record, and a 2017 annual peak streamflow ranking in the top five of all annual peaks for a given station that were used to 

calculate annual exceedance probabilities.

[mi2, square miles]
6 Characterization of Peak Streamflows and Flood Inundations from Hurricane Harvey, 2017

Table 2. U.S. Geological Survey streamflow-gaging stations in southeast Texas with at least 15 years of record, no large data gaps in 

the period of record, and a 2017 annual peak streamflow ranking in the top five of all annual peaks for a given station that were used to 

calculate annual exceedance probabilities.—Continued

[mi2, square miles]

Site 

identification 

number 

(fig. 2)

Station 

number Station name

Drainage 

area 

(mi2)

Latitude

(decimal 

degrees)

Longitude

(decimal 

degrees)

40 08073700 Buffalo Bayou at Piney Point, Texas 299 29.74690 95.52355

41 08074000 Buffalo Bayou at Houston, Texas 336 29.76023 95.40855

42 08074020 Whiteoak Bayou at Alabonson Road, Houston, Texas 34.5 29.87056 95.48028

43 08074150 Cole Creek at Deihl Road, Houston, Texas 7.50 29.85111 95.48778

44 08074250 Brickhouse Gully at Costa Rica Street, Houston, Texas 11.4 29.82778 95.46917

45 08074500 Whiteoak Bayou at Houston, Texas 95.1 29.77523 95.39716

46 08074800 Keegans Bayou at Roark Road near Houston, Texas 12.7 29.65662 95.56217

47 08075000 Brays Bayou at Houston, Texas 94.9 29.69717 95.41216

48 08075400 Sims Bayou at Hiram Clarke Street, Houston, Texas 20.2 29.61884 95.44605

49 08075500 Sims Bayou at Houston, Texas 63.0 29.67440 95.28938

50 08075730 Vince Bayou at Pasadena, Texas 8.26 29.69467 95.21632

51 08075770 Hunting Bayou at Interstate Highway 610, Houston, Texas 16.1 29.79328 95.26799

52 08075780 Greens Bayou at Cutten Road near Houston, Texas 8.65 29.94911 95.51966

53 08075900 Greens Bayou near US Highway 75 near Houston, Texas 36.6 29.95689 95.41799

54 08076000 Greens Bayou near Houston, Texas 68.7 29.91828 95.30688

55 08076180 Garners Bayou near Humble, Texas 31.0 29.93386 95.23396

56 08076500 Halls Bayou at Houston, Texas 28.7 29.86167 95.33472

57 08076700 Greens Bayou at Ley Road, Houston, Texas 182 29.83717 95.23327

58 08077600 Clear Creek near Friendswood, Texas 122 29.51746 95.17854

59 08110100 Davidson Creek near Lyons, Texas 195 30.41965 96.54025

60 08111700 Mill Creek near Bellville, Texas 376 29.88106 96.20524

61 08114000 Brazos River at Richmond, Texas 45,107 29.58246 95.75773

62 08116650 Brazos River near Rosharon, Texas 45,339 29.34969 95.58244

63 08117500 San Bernard River near Boling, Texas 727 29.31358 95.89384

64 08160400 Colorado River above La Grange, Texas 40,874 29.91245 96.90387

65 08160800 Redgate Creek near Columbus, Texas 17.3 29.79888 96.53194

66 08161000 Colorado River at Columbus, Texas 41,640 29.70635 96.53692

67 08162000 Colorado River at Wharton, Texas 42,003 29.30914 96.10385

68 08162500 Colorado River near Bay City, Texas 42,240 28.97415 96.01246

69 08164000 Lavaca River near Edna, Texas 817 28.95998 96.68637

70 08164300 Navidad River near Hallettsville, Texas 332 29.46691 96.81276

71 08164390 Navidad River at Strane Park near Edna, Texas 579 29.06554 96.67414

72 08164450 Sandy Creek near Ganado, Texas 289 29.16025 96.54636

73 08175800 Guadalupe River at Cuera, Texas 4,934 29.09053 97.32971

74 08176500 Guadalupe River at Victoria, Texas 5,198 28.79305 97.01304
Weather Conditions Before and During the Flood 7

Purpose and Scope

The purpose of this report is to document the 

characterization of peak streamflows and flood inundation 

of selected areas in southeastern Texas. The data collection 

methods, flood-peak magnitudes, and flood-inundation 

products generated by the USGS in support of the FEMA 

response-and-recovery operations following the August and 

September 2017 flood event in southeastern Texas caused 

by rainfall from Hurricane Harvey are described. This report 

includes (1) a description of the atmospheric conditions and 

the temporal and spatial patterns of rainfall that triggered 

the flooding and a description of the flood and its effects, 

(2) a description of the flagging and surveying of high-water 

marks (HWMs), (3) analysis of flood-peak magnitudes and 

their statistical probabilities at selected locations, (4) and 

geographic information system (GIS) analysis of HWM 

locations and elevations to produce flood-inundation maps 

(areal extent of the maximum depth of flooding) for five 

heavily flooded major river basins primarily in Texas, 

six smaller coastal basins, and coastal areas in Texas from 

Port Aransas to Matagorda Bay. Because one of the five 

heavily flooded river basins consists of the Sabine River and 

its tributaries, and the Sabine River forms part of the boundary 

between Texas and Louisiana, the study includes a small part 

of southwestern Louisiana. The wording and presentation of 

the material in this report are based on a previous USGS report 

(Watson and others, 2017); the contents of each section are 

modified from this previous report. In addition to the flooded 

river basins and areas described in this report, other river 

basins and areas also flooded as a result of Hurricane Harvey; 

documenting the flooding in other basins and areas affected by 

Hurricane Harvey is beyond the scope of this report. 

Description of Study Area

The study area consists of five major river basins in 

southeastern Texas and a small part of southwestern Louisiana 

along the coast of the Gulf of Mexico, six smaller coastal 

basins that drain directly to the Gulf of Mexico, and coastal 

areas from Port Aransas to Matagorda Bay. Areas affected 

by flooding described within this report lie within the West 

Gulf Coastal Plain physiographic section (Fenneman, 1946; 

fig. 1). In general, the study area is characterized by coastal 

prairies that extend westward from the Texas and Louisiana 

border to Corpus Christi along the coast of the Gulf of Mexico 

and is primarily covered by heavy grasses. The soil in the 

study area is mostly heavy clay. The study area also extends 

into East Texas, which is covered by pine forests with some 

hardwood timber with sandy loam soils (Texas State Historical 

Association, 2018; Texas A&M Forest Service, 2018). Landsurface elevations within the study area range from about 0 

to 602 feet (ft) relative to the North American Vertical Datum 

of 1988 (NAVD 88). The study area is primarily within two 

National Weather Service (NWS) climate divisions: East Texas 

and Upper Coast (NOAA, 2017; fig. 1). According to data 

retrieved from the NWS National Climatic Data Center for the 

period from 1901 through 2013, mean annual precipitation for 

the East Texas climate division is 45.74 in., and mean annual 

precipitation for the Upper Coast climate division is 45.27 in. 

(NOAA, 2014).

Weather Conditions Before and During 

the Flood

On August 17, 2017, Harvey began as a tropical 

depression about 625 miles (mi) east of St. Vincent of 

the Lesser Antilles and became a weak tropical storm on 

August 18 near Barbados (Blake and Zelinsky, 2018). The 

storm then dissipated into a tropical wave over the Caribbean 

Sea on August 19 but re-formed into a tropical storm over the 

Bay of Campeche on August 23, eventually intensifying into 

a Category 4 hurricane on August 25. Harvey made landfall 

on August 25 as a Category 4 hurricane on the northern end 

of San Jose Island about 5 mi east of Rockport, Tex. (fig. 1) 

and made a second landfall on the mainland of Texas about 

3 hours later. Harvey had sustained winds of 132 mi/h when 

it hit the northern end of San Jose Island and sustained winds 

of 121 mi/h when it hit the Texas mainland. Harvey weakened 

rapidly over land to a tropical storm after about 12 hours and 

maintained 40 mi/h winds for the next day or so (Blake and 

Zelinsky, 2018).

After making landfall, the storm made a slow loop 

beginning on August 26 and continuing into August 27 before 

drifting eastward and southeastward over the next couple of 

days. The center of the storm passed south of the Houston 

area, but heavy rains fell near a stationary front on the north 

and east sides of the storm. The center of the storm moved 

offshore over Matagorda Bay on August 28 and eventually 

turned to the north-northeast about 69 mi offshore from the 

Texas coast on August 29. Harvey continued on that path 

and eventually made landfall in southwestern Louisiana 

on August 30 with 46-mi/h sustained winds. The storm 

weakened from a tropical storm to a tropical depression 

late on August 30 and then moved northeastward over 

northern Louisiana. By August 31, the storm had moved over 

southeastern Arkansas, northern Mississippi, and central 

Tennessee. By the time the storm reached Tennessee, it had 

become an extratropical cyclone and eventually dissipated on 

September 2 in northern Kentucky (Blake and Zelinsky, 2018).

Harvey was the most significant rainfall event in United 

States history in scope and rainfall totals since rainfall records 

began during the 1880s. For the period from August 25 

through September 1, 2017, the highest rainfall total from 

the storm at a single location was 60.58 in. near Nederland, 

Tex. (table 1). A location near Groves, Tex. (fig. 1) also 

reported 60.54 in. of rain during the same period (table 1; 

Blake and Zelinsky, 2018). The record rainfall amounts of 
8 Characterization of Peak Streamflows and Flood Inundations from Hurricane Harvey, 2017

60.58 and 60.54 inches listed in table 1 are from Jefferson 

County Drainage District rain gages, which were probably 

not used by the National Weather Service to create the maps 

depicting rainfall amounts in the study area. To create maps 

of rainfall amounts, the National Weather Service averages 

rainfall over large areas, which could also account for 

discrepancies between the maximum rainfall amounts depicted 

in figures 1–2 and the individual point values exceeding 

60 inches of rain listed in table 1. The previous record storm 

total for the continental United States was 48.00 in. of rain 

near Medina, Tex., in 1978 which was associated with Tropical 

Storm Amelia. During Harvey, 20 NOAA meteorological 

stations reported rainfall totals in excess of 48.00 in. across 

southeastern Texas for the period from August 25 through 

September 1, 2017 (table 1; Blake and Zelinsky, 2018). Not 

only were Harvey’s rainfall totals exceptional, but the areal 

extent of heavy rainfall was also larger than the areal extents 

of previous events with rainfall totals exceeding 15 in. (Blake 

and Zelinsky, 2018).

The heavy rainfall led to widespread flooding and 

record streamflows. In Texas, 74 USGS streamflow-gaging 

stations with at least 15 years of record (table 2) had annual 

peak streamflows for the 2017 water year1 resulting from 

Harvey that ranked among the top five of all annual peak 

streamflows recorded for that station (table 3). For 40 of these 

74 streamflow-gaging stations (54 percent), the 2017 annual 

peak streamflow ranked as the largest ever recorded for the 

station (table 3).

Harvey also produced 57 tornadoes (as reported by 

October 1, 2017) in Texas, Louisiana, Mississippi, Alabama, 

and Tennessee, with about half of them occurring near and 

south of the Houston metropolitan area (Blake and Zelinsky, 

2018). Most of the tornadoes were relatively weak and 

resulted in no fatalities.

Methods

The methods used to identify, document, and reference 

HWMs resulting from flooding as well as the methods used 

to create flood-inundation maps from HWMs are described 

in this section. Also discussed are the methods by which 

the estimation of flood magnitude and frequency were 

developed through analysis of the annual peak streamflows 

at 74 streamflow-gaging stations operated by the USGS. The 

USGS collects streamflow data at more than 8,000 streamflowgaging stations nationwide in cooperation with local, state, and 

Federal agencies. This includes more than 600 streamflowgaging stations currently (2018) operating in Texas. Collection 

1

The water year is the annual period from October 1 through September 30 

and is designated by the year in which the period ends. For example, the 2017 

water year is from October 1, 2016, through September 30, 2017.

of streamflow data documents the extent and effects of 

flooding. Streamflow data collected before and during flooding 

are vital because they can provide advanced flood warning, 

forecasts of the extent and potential effects of flooding, and 

information useful in optimizing allocation of emergency 

management resources to the most severely affected areas. All 

streamflow data used in support of this report can be accessed 

from the USGS National Water Information System (USGS, 

2018a).

Collection of High-Water Mark Data

HWMs are the evidence of the highest water levels 

during a flood and provide valuable data for understanding 

flood events (Koenig and others, 2016). The USGS followed 

the guidance provided by Koenig and others (2016) for 

identification and documentation of HWMs. The best HWMs 

are formed from small seeds or floating debris carried by 

floodwaters that adhere to smooth surfaces or lodge in tree 

bark to form a distinct line. Stain lines on buildings, fences, 

and other structures also provide excellent marks. HWMs 

are best identified immediately following the peak stage of a 

flood event because time and weather (wind, rain, and sun) 

may blow, wash, or fade away the evidence of the peak water 

line. Care was taken to identify HWMs as far from the main 

channel as feasible, where velocities generally are slower and 

where wave action and pileup or drawdown effects of fastmoving waters are minimized. Information about the HWMs 

identified by the USGS for this flood event was made available 

through the USGS Short-Term Network (STN) (USGS, 

2018b), which is an online interface created to facilitate the 

dissemination of field data. Additional information, including 

a download portal for HWM information from the Flood 

Event Viewer, is available from the USGS Hurricane Harvey 

web page at https://www.usgs.gov/special-topic/hurricaneharvey (USGS, 2018c).

Identification of HWMs by the USGS began on 

September 2, 2017, and continued through October 5, 2017. 

After an acceptable HWM was found, a more permanent 

identification mark was established, such as a Parker-Kalon 

nail with a disk, a stake, a chiseled mark, or a paint line. 

Written descriptions, sketches, photographs, and Global 

Positioning System (GPS) horizontal measurements obtained 

with a hand-held GPS unit were made so the marks could 

easily be found later and surveyed to the standard vertical 

datum, NAVD 88. USGS field crews surveyed 2,123 HWMs 

to obtain water-surface elevations, in feet above NAVD 88. 

In some locations, several water-surface elevations were 

averaged to obtain 1 water-surface elevation, resulting in 

1,258 water-surface elevations. The distance of the HWMs 

above the land surface was also recorded in feet for all of the 

HWMs.
Methods 9

Table 3. Peak gage heights, peak streamflows, and estimated annual exceedance probabilities for the August and September 2017 

Hurricane Harvey-related flood event at 74 selected U.S. Geological Survey streamflow-gaging stations in southeastern Texas.—

Continued

[ft, feet; ft3/s, cubic feet per second; AEP, annual exceedance probability]

Site 

identification 

number 

(fig. 2)

Station 

number

Peak streamflow for August 2017 flood Number 

of annual 

peak 

streamflows 

in period 

of record

AEP for observed August 2017 flood

Date of 

peak 

streamflow

Peak 

gage 

height 

(ft)

Peak 

streamflow 

(ft3/s)

Rank of peak 

streamflow 

among all 

annual peak 

streamflows

Estimate 

(percent)

66.7 percent 

confidence interval

Lower 

(percent)

Upper 

(percent)

1 08026000 9/1/2017 46.29 84,900 5 62 4.0 4.7 11.1

2 08028500 9/2/2017 38.93 113,000 3 93 2.3 1.5 4.8

3 08029500 8/30/2017 21.08 39,500 2 66 1.0 1.1 4.8

4 08030500 9/2/2017 31.60 161,000 2 105 0.4 0.7 3.0

5 08031000 8/30/2017 26.85 26,500 1 47 0.3 0.4 3.7

6 08039100 8/30/2017 17.49 15,700 4 60 5.4 3.6 9.5

7 08040600 8/31/2017 80.70 91,000 12 68 1.0 1.1 4.7

8 08041500 8/30/2017 35.96 182,000 1 82 0.3 0.2 2.2

9 08041700 8/30/2017 39.68 50,500 1 50 1.0 0.4 3.5

10 08065800 8/28/2017 26.03 38,700 3 50 3.8 2.8 8.9

11 08066250 8/29/2017 48.34 110,000 2 52 2.7 1.4 6.1

12 08066300 8/29/2017 36.11 15,200 1 52 1.9 0.4 3.4

13 08067000 8/31/2017 32.70 126,100 2 76 1.4 1.0 4.2

14 08067500 8/28/2017 59.06 10,600 1 46 0.3 0.4 3.8

15 08067650 8/28/2017 46.12 75,400 1 45 1.5 0.4 3.9

16 08068000 8/29/2017 126.93 122,000 1 83 0.8 0.2 2.1

17 08068090 8/29/2017 94.87 131,000 1 33 2.4 0.6 5.3

18 08068275 8/28/2017 166.38 48,900 1 18 4.5 1.0 9.5

19 08068325 8/28/2017 133.87 11,100 1 27 1.8 0.7 6.4

20 08068390 8/28/2017 140.27 3,660 3 18 14.0 7.9 23.6

21 08068400 8/28/2017 137.49 6,300 4 18 9.7 12.1 29.9

22 08068450 8/28/2018 117.12 12,500 2 25 3.4 2.9 12.4

23 08068500 8/28/2017 111.52 78,400 2 80 1.1 0.9 4.0

24 08068720 8/28/2017 162.85 12,800 1 42 0.5 0.4 4.2

25 08068740 8/28/2017 149.30 22,600 1 43 1.1 0.4 4.1

26 08068780 8/28/2017 161.23 9,140 2 35 2.3 2.1 8.9

27 08068800 8/28/2017 129.97 17,500 2 35 1.9 2.1 8.9

28 08068900 8/28/2017 113.82 23,100 1 31 1.3 0.6 5.6

29 08069000 8/28/2017 97.12 31,500 1 75 0.5 0.2 2.4

30 08070000 8/28/2017 27.17 109,000 1 79 0.8 0.2 2.2

31 08070200 8/29/2017 81.15 120,000 1 33 0.5 0.6 5.3

32 08070500 8/28/2017 26.63 21,100 4 74 3.3 2.9 7.7

33 08071000 8/28/2017 25.77 77,000 1 54 0.8 0.3 3.3

34 08071280 8/29/2017 37.86 32,800 1 33 2.6 0.6 5.3

35 08072300 8/28/2017 118.28 17,900 1 40 0.4 0.5 4.4

36 08072730 8/27/2017 114.71 15,700 2 40 3.7 1.8 7.9

37 08072760 8/27/2017 111.85 9,000 3 40 6.2 3.5 11.0

38 08073500 8/30/2017 77.31 13,800 1 73 0.4 0.2 2.4

Table 3. Peak gage heights, peak streamflows, and estimated annual exceedance probabilities for the August and September 2017 

Hurricane Harvey-related flood event at 74 selected U.S. Geological Survey streamflow-gaging stations in southeastern Texas.

[ft, feet; ft3/s, cubic feet per second; AEP, annual exceedance probability]
10 Characterization of Peak Streamflows and Flood Inundations from Hurricane Harvey, 2017

Table 3. Peak gage heights, peak streamflows, and estimated annual exceedance probabilities for the August and September 2017 

Hurricane Harvey-related flood event at 74 selected U.S. Geological Survey streamflow-gaging stations in southeastern Texas.—

Continued

[ft, feet; ft3/s, cubic feet per second; AEP, annual exceedance probability]

Site 

identification 

number 

(fig. 2)

Station 

number

Peak streamflow for August 2017 flood Number 

of annual 

peak 

streamflows 

in period 

of record

AEP for observed August 2017 flood

Date of 

peak 

streamflow

Peak 

gage 

height 

(ft)

Peak 

streamflow 

(ft3/s)

Rank of peak 

streamflow 

among all 

annual peak 

streamflows

Estimate 

(percent)

66.7 percent 

confidence interval

Lower 

(percent)

Upper 

(percent)

39 08073600 8/31/2017 71.22 14,600 1 46 0.4 0.4 3.8

40 08073700 8/31/2017 62.84 15,000 1 47 0.5 0.4 3.7

41 08074000 8/28/2017 41.90 36,400 12 83 0.3 0.9 3.8

42 08074020 8/27/2017 77.84 15,500 1 34 3.1 0.5 5.1

43 08074150 8/27/2017 74.58 2,620 5 51 8.1 5.7 13.4

44 08074250 8/27/2017 66.97 11,800 2 47 1.4 1.6 6.7

45 08074500 8/27/2017 44.31 50,600 1 83 <0.2 0.2 2.1

46 08074800 8/27/2017 75.21 9,870 1 52 0.6 0.4 3.4

47 08075000 8/27/2017 45.67 35,200 1 83 2.5 0.2 2.1

48 08075400 8/27/2017 46.78 13,500 1 53 0.7 0.3 3.3

49 08075500 8/27/2017 26.56 39,700 1 65 0.3 0.3 2.7

50 08075730 8/27/2017 22.32 8,430 1 46 0.8 0.4 3.8

51 08075770 8/27/2017 37.12 6,680 1 54 0.6 0.3 3.3

52 08075780 8/27/2017 111.84 5,840 1 53 4.3 0.3 3.3

53 08075900 8/27/2017 85.84 12,000 4 52 4.7 4.1 10.9

54 08076000 8/27/2017 62.88 26,400 2 65 1.3 1.1 4.9

55 08076180 8/28/2017 57.92 24,900 1 31 1.0 0.6 5.6

56 08076500 8/28/2017 57.54 5,550 2 65 2.8 1.1 4.9

57 08076700 8/28/2017 44.85 128,000 1 45 0.5 0.4 3.9

58 08077600 8/29/2017 24.25 44,100 1 21 0.5 0.9 8.2

59 08110100 8/28/2017 19.47 23,500 2 55 2.5 1.3 5.8

60 08111700 8/28/2017 22.49 73,800 2 47 1.5 1.6 6.7

61 08114000 9/1/2017 55.19 122,000 2 99 0.9 0.7 3.2

62 08116650 8/29/2017 52.65 133,000 1 48 0.4 0.4 3.7

63 08117500 8/31/2017 43.79 54,500 1 63 0.2 0.3 2.8

64 08160400 8/28/2017 54.14 118,000 1 29 5.2 0.6 6.0

65 08160800 8/27/2017 26.60 5,290 3 56 6.8 2.5 8.0

66 08161000 8/29/2017 48.13 165,000 3 104 1.1 1.4 4.3

67 08162000 8/31/2017 50.47 93,600 4 87 3.7 2.5 6.6

68 08162500 9/2/2017 46.16 89,000 1 71 1.6 0.3 2.5

69 08164000 8/29/2017 32.53 74,300 4 80 3.2 2.7 7.2

70 08164300 8/28/2017 36.38 61,900 1 56 0.6 0.3 3.1

71 08164390 8/29/2017 31.28 26,000 1 20 6.4 0.9 8.6

72 08164450 8/29/2017 25.84 20,500 3 40 7.9 3.5 11.0

73 08175800 8/29/2017 44.36 178,000 2 54 3.4 1.4 5.9

74 08176500 8/30/2017 31.30 86,500 5 83 8.0 3.5 8.4

1

Hurricane Harvey peak streamflow ranked second behind a historic peak of record.
Methods 11

During the mapping process, the HWMs used to create 

flood-inundation maps (Watson and others, 2018) were 

checked for location and elevation accuracy by comparing 

field note diagrams and descriptions to aerial photography 

and detailed street and parcel maps. If the location could not 

be determined accurately or if the elevation was substantially 

different from the elevations of other HWMs in the area, 

the HWM was not used. Also, some HWMs were not used 

because they were the result of localized flooding of small 

areas and did not represent the water-surface elevation of the 

surrounding area.

Flood-Inundation Mapping

Nineteen flood-inundation maps in 11 river and coastal 

basins were created by using GIS for areas near rivers that 

flooded as a result of Harvey in southeastern Texas and 

southwestern Louisiana (fig. 3). The flood-inundation maps 

estimate the areal extent of the maximum depth of flooding 

that corresponds to the HWMs identified and surveyed by 

USGS field crews following the flood event. The waterbody, 

reach length, and number of HWMs used to generate the 

flood-inundation maps are summarized (table 4). 

The first step in the generation of the flood-inundation 

maps was the creation of a flood-elevation raster surface. GIS 

surfaces documenting the areal extent of the maximum depth 

of flooding were created independently for each area that was 

mapped by using the HWM elevations, cross sections across 

the direction of flow at the HWMs and streamflow-gaging 

stations, and a GIS interpolation technique—the ArcGIS 

Topo to Raster tool (http://pro.arcgis.com/en/pro-app/toolreference/3d-analyst/how-topo-to-raster-works.htm, accessed 

February 13, 2018) as described by Musser and others 

(2016). A different method was used in the coastal areas with 

relatively low topography and large areas of overland flooding. 

This interpolation method used the HWM elevations as points 

rather than cross sections and interpolated between these 

elevations to generate the flood-elevation surface by using 

the ArcGIS Topo to Raster tool with the point interpolation 

procedure. A geographic limit was placed on the extent of the 

generated surface on the basis of the distribution of HWMs 

and an understanding of the natural hydrologic flow in each 

area that was mapped.

The flood-elevation surface that was created by using GIS 

interpolation was then combined with digital elevation model 

(DEM) data, derived from light detection and ranging (lidar) 

data, with cell sizes of 1.4–3.0 meters (USGS Lidar Point 

Cloud TX Neches, USGS, The National Map, 2018; Texas 

Natural Resources Information System, 2006, 2007, 2008, 

2009, 2010, 2011a–d, 2012, 2013, 2014, 2016, 2017). A DEM 

is digital point representation of a surface; in this instance, the 

DEM is a representation of the earth’s surface in the study area 

and mimics the topography of the land. An inundated area was 

depicted where the interpolated flood-elevation surface was 

higher than the DEM land surface. The maximum depth of 

flooding was determined as the difference between the floodelevation surface and the DEM land surface. For this study, 

the flood-inundation surfaces were not modified to show any 

bridges that were not inundated. Our modeling methods did 

not use a hydraulic analysis, so we cannot definitively show 

whether a bridge was inundated or not.

The flood-elevation interpolation method used to develop 

the coastal water-surface elevation layer used the HWM and 

USGS streamflow-gaging station peak stage water-surface 

elevation values as points and interpolated between these 

elevations to generate the water-surface elevation by using 

the ArcGIS Topo to Raster tool with the point interpolation 

procedure (http://pro.arcgis.com/en/pro-app/tool-reference/3danalyst/how-topo-to-raster-works.htm; Esri, 2017). This 

approach was used when the flooded area was adjacent to a 

large, low-gradient body of water, such as a swamp, or when 

the flooded area was a coastal community on the Gulf of 

Mexico.

Uncertainties in the mapped extent of the maximum 

depth of flooding exist within the maps because of the 

mapping methods used and the number and spatial distribution 

of HWMs in a given mapped reach. Hydraulic models were 

not used to determine the extent or depth of flood inundation. 

Without hydraulic models, changes in land-surface features 

in flood plains, the timing of the flooding that may have 

occurred from some of the smaller inflow tributaries versus the 

larger main stem tributaries, and the intermingling flows from 

adjacent streams are not taken into account. In locations where 

HWMs are spaced farther apart, there is a greater possibility of 

decreased accuracy of spatial interpretation of the extent of the 

maximum depth of flood inundation. Within a given mapped 

area, some extrapolation was performed beyond the most 

upstream and downstream HWMs. In many cases, the mapped 

boundary was extended to some anthropogenic structure, such 

as a road or bridge crossing.

Flood Exceedance Probabilities of Peak 

Streamflows

After a major flood, emergency managers and water 

resources engineers often need to know the expected 

frequency of peak streamflow for the streamflow magnitudes 

observed during the event. Flood-frequency analyses for 

streamflow-gaging stations with sufficient record (defined 

as greater than or equal to 15 years for the purposes of this 

report) can provide insight into the occurrence or likelihood 

of peak streamflows of varying magnitudes. The annual 

exceedance probability (AEP) for a particular location is the 

probability of that streamflow being equaled or exceeded 

during a given water year and is determined from the existing 

annual peak streamflow data for a streamflow-gaging station. 

For example, an AEP of 0.01 means there is a 1-percent 

(AEP ×100) chance that a specific peak streamflow will 

occur at a given location in a given year. Stated another way, 

the odds are 1 in 100 that the indicated streamflow will be 
12 Characterization of Peak Streamflows and Flood Inundations from Hurricane Harvey, 2017

Figure 3. Locations of U.S. Geological Survey streamflow-gaging stations, selected cities and counties, parishes, and river basins 

within the study area in southeastern Texas and southwestern Louisiana.

TEXAS NEW MEXICO

OKLAHOMA ARKANSAS

LOUISIANA

Study area

MEXICO

UNITED STATES

BEAUREGARD

PARISH

CALCASIEU

PARISH

CAMERON

PARISH

TEXAS

LOUISIANA

Rosenberg

SAN 

AUGUSTINE

COUNTY

MADISON

COUNTY

BURLESON

COUNTY

CHAMBERS

COUNTY

GALVESTON

COUNTY

5

Texas City

East Matagorda 

Bay Subbasin

West Matagorda 

Bay Subbasin

Aransas

Bay Subbasin

East San Antonio

Bay Subbasin

West San Antonio

Bay Subbasin

New Ulm

Sugar Land

Houston

Victoria

Beaumont

Galveston

Lake Jackson

Freeport

Corpus Christi

9

8

7

6

4

3 2

1

74

73

72

71

70

69

68

67

66

65

64

63

62

61

60

59

58

34

33

32 31

30

21 16

15

14 13

12

11

10

HARRIS

COUNTY

POLK

COUNTY

TYLER

COUNTY

LIBERTY

COUNTY

BRAZORIA

COUNTY

COUNTY

JASPER

HARDIN

COUNTY

DEWITT

COUNTY

LAVACA

COUNTY

GOLIAD

COUNTY

WHARTON

COUNTY

FAYETTE

COUNTY

COUNTY

NEWTON

VICTORIA

COUNTY

TRINITY

COUNTY

WALKER

COUNTY GRIMES

COUNTY

MATAGORDA

COUNTY

COLORADO

COUNTY

NUECES

COUNTY

AUSTIN

COUNTY JEFFERSON

COUNTY

JACKSON

COUNTY

REFUGIO

COUNTY

ANGELINA

COUNTY

FORT BEND

COUNTY

MONTGOMERY

COUNTY

WALLER

COUNTY

SAN PATRICIO

COUNTY

SAN JACINTO

COUNTY

WASHINGTON

COUNTY

CALHOUN

COUNTY

ORANGE

COUNTY

ARANSAS

COUNTY

GULF OF MEXICO

Base modified from U.S. Geological Survey digital data 

Albers Equal Area Projection, Texas Centric Mapping System 

North American Datum of 1983 (2011)

Corpus Christi Bay

98° 96° 94°

32°

30°

28°

0 50 100 MILES

0 50 100 KILOMETERS

Matagorda Bay

EXPLANATION

U.S. Geological Survey streamflowgaging station and site identification

number–Used for annual exceedance

probability calculation, see table 2

72

Lower Brazos Basin

Coastal basins—East Matagorda Bay Subbasin,

West Matagorda Bay Subbasin, East San Antonio

Bay Subbasin, West San Antonio Bay Subbasin,

and Aransas Bay Subbasin

Lower Neches Subbasin

Pine Island Bayou Subbasin

Sabine Basin

San Bernard Coastal Basin

San Jacinto Basin

Basin boundary

Subbasin boundary

Austin

Fort Worth Dallas

Houston

Victoria

Beaumont Rosenberg

Galveston

Texas City

Sugar Land

Lake 

Jackson Corpus 

Christi

61

58

57 56

55

54

53

52

51

50

49 48

47 46

45

44 43

42

41

40 39 38

37

36

35

34

33

32

31

29 28

27

26

25 24

23

22

20 21

18 19 17

16

14

MONTGOMERY

COUNTY

FORT BEND

COUNTY

HARRIS

COUNTY

Houston

Sugar Land

Rosenberg

Area enlarged
Methods 13

equaled or exceeded in a given year. The traditional concept of 

recurrence interval is directly related to the AEP. By definition, 

the recurrence interval (in years) is equal to 1 divided by the 

AEP. For example, the AEP of 0.01 (or 1 percent) corresponds 

to the 100-year flood (Holmes and Dinicola, 2010).

During August and September 2017, USGS personnel 

made more than 180 streamflow measurements in the study 

area by direct methods (Rantz and others, 1982a; Turnipseed 

and Sauer, 2010) and indirect methods (Benson and 

Dalrymple, 1967; Rantz and others, 1982b) at 97 locations. 

Many of the streamflow measurements were made to 

verify the accuracy of the stage-streamflow rating curve 

or to extend the stage-streamflow rating curve for a given 

streamflow-gaging station (Rantz and others, 1982a). The 

stage-streamflow rating curve for a given streamflow-gaging 

station is used to calculate instantaneous streamflow values for 

given stage values, which in turn are used to populate USGS 

annual peak streamflow files. Streamflow-gaging stations with 

the longest annual peak streamflow records are considered the 

most reliable for estimating AEPs. 

The August and September 2017 peak streamflows were 

analyzed by using the PeakFQ software (Flynn and others, 

2006) following guidance provided in USGS Office of Surface 

Water Technical Memorandum 2013.01 (Mason, 2012). For 

selected streamflow-gaging stations, AEPs corresponding 

to peak streamflows that occurred during the August and 

September 2017 flood and streamflows associated with 

selected AEPs (1, 0.5, and 0.2 percent; table 5) were estimated 

by using the Expected Moments Algorithm (Cohn and others, 

1997, 2001) in the USGS PeakFQ software (Flynn and others, 

2006; USGS, 2018d). The Interagency Advisory Committee 

on Water Data (IACWD) provides standard methods for 

computing peak streamflow frequency in a recently (2018) 

published document referred to as Bulletin 17C (England 

and others, 2018). Bulletin 17C is an update to Bulletin 17B 

(IACWD, 1982). Flood computation equations and algorithms 

in Bulletin 17C have been implemented in the PeakFQ 

software (Veilleux and others, 2014; USGS, 2018d). The 

PeakFQ software includes an updated version of the Expected 

Moments Algorithm, which allows for the incorporation of 

more complicated or subjective measurements such as paleohydrology, interval peaks, and sophisticated gap-infill for 

years of missing annual peak streamflow records. The PeakFQ 

software was updated to include the multiple Grubbs-Beck 

low outlier test, which is capable of identifying potentially 

influencing low floods. The multiple Grubbs-Beck low outlier 

test is an improvement over the single Grubbs-Beck test 

(Grubbs and Beck, 1972; England and others, 2018). 

Table 4. Counties, parishes, waterbodies, reach lengths, and number of high-water marks used to generate flood-inundation maps.

Texas County/

Louisiana Parish1 Waterbody

Reach 

length 

(miles)2

Number 

of highwater 

marks

Waller, Austin, Fort Bend, and 

Brazoria

Brazos River 171 46

Orange, Jasper, Hardin, Jefferson, and 

Tyler

Neches River 131 33

Liberty, Hardin, Jefferson, and 

Orange

Pine Island Bayou, tributary to the Neches River 68 34

Jasper, Newton, Orange, Jefferson, 

Beauregard, Calcasieu, and 

Cameron

Sabine River 131 43

Jasper and Newton Big Cow Creek, tributary to the Sabine River 37 8

Jasper, Newton, and Orange Cow Bayou, tributary to the Sabine River 23 19

Colorado, Austin, Wharton, Fort 

Bend, and Brazoria

San Bernard River 99 34

Waller, Harris, Montgomery, San 

Jacinto, and Liberty

San Jacinto River and tributaries 403 106

Matagorda, Jackson, Calhoun, 

Victoria, Refugio, San Patricio, and 

Aransas

Coastal Basins (including Peyton Creek, Big Boggy Creek, Little Boggy 

Creek, Tres Palacios River, East Carancahua Creek, West Carancahua 

Creek, and Keller Creek)

234 129

1

Bold-faced names are parishes in Louisiana.

2

Indicates total reach length mapped within a basin computed as the sum of the main stem and tributaries.
14 Characterization of Peak Streamflows and Flood Inundations from Hurricane Harvey, 2017

Table 5. Site identification number, station number, and expected peak streamflows for selected annual exceedance probabilities with 

95 percent confidence intervals at 74 selected U.S. Geological Survey streamflow-gaging stations in southeastern Texas.—Continued

[ft3/s, cubic feet per second; AEP, annual exceedance probability]

Site 

identification 

number 

(fig. 2)

Station 

number

Expected peak streamflows for selected AEP with 95 percent confidence intervals

(ft3/s)

1 percent AEP 

(100-year recurrence)

0.5 percent AEP 

(200-year recurrence)

0.2 percent AEP 

(500-year recurrence)

Estimate 

95 percent 

confidence interval Estimate

95 percent 

confidence interval Estimate 

95 percent

 confidence interval

Lower Upper Lower Upper Lower Upper

1 08026000 140,000 103,000 276,000 176,000 123,000 425,000 234,000 153,000 762,000

2 08028500 141,000 110,000 222,000 168,000 126,000 294,000 208,000 148,000 419,000

3 08029500 39,100 22,700 135,000 54,700 29,200 267,000 83,300 39,600 672,000

4 08030500 138,000 113,000 193,000 157,000 124,000 234,000 182,000 137,000 298,000

5 08031000 12,000 5,880 62,100 17,900 7,380 157,000 29,800 9,720 572,000

6 08039100 26,700 18,000 56,600 31,800 20,200 77,500 39,100 22,700 116,000

7 08040600 90,800 65,500 166,000 111,000 76,000 238,000 142,000 91,200 386,000

8 08041500 106,000 66,600 289,000 140,000 82,100 490,000 198,000 104,000 973,000

9 08041700 50,700 28,900 263,000 68,600 36,000 489,000 99,800 46,800 1,060,000

10 08065800 55,400 39,700 92,000 64,300 43,800 119,000 75,900 48,200 163,000

11 08066250 126,000 106,000 174,000 137,000 113,000 206,000 150,000 121,000 256,000

12 08066300 18,500 12,900 40,100 22,800 15,100 61,100 29,100 17,900 106,000

13 08067000 132,000 108,000 197,000 148,000 118,000 244,000 169,000 130,000 322,000

14 08067500 8,290 6,270 15,000 9,410 6,820 18,900 11,000 7,480 25,500

15 08067650 97,700 39,000 1,840,000 158,000 54,100 5,360,000 292,000 80,500 22,400,000

16 08068000 111,000 74,400 217,000 136,000 85,100 304,000 169,000 97,000 464,000

17 08068090 196,000 98,200 752,000 263,000 122,000 1,240,000 374,000 155,000 2,340,000

18 08068275 109,000 42,100 870,000 147,000 52,300 1,580,000 212,000 66,500 3,350,000

19 08068325 14,200 7,580 48,600 18,700 9,290 78,100 26,100 11,700 143,000

20 08068390 8,600 5,160 26,700 10,200 5,830 37,200 12,500 6,700 56,700

21 08068400 15,100 8,260 61,200 18,800 9,690 93,900 24,700 11,700 163,000

22 08068450 24,600 11,200 288,000 34,500 14,400 598,000 51,900 19,400 1,490,000

23 08068500 80,100 49,400 317,000 109,000 62,100 608,000 160,000 81,400 1,330,000

24 08068720 9,790 5,730 49,400 12,700 6,880 84,400 17,500 8,510 171,000

25 08068740 23,800 9,540 163,000 36,800 12,300 441,000 64,700 16,700 1,780,000

26 08068780 12,200 7,270 32,700 15,200 8,530 47,400 19,700 10,200 76,000

27 08068800 21,700 13,400 77,600 26,900 15,400 125,000 34,700 18,200 233,000

28 08068900 24,600 16,600 52,400 29,200 18,800 69,900 35,700 21,700 101,000

29 08069000 26,200 19,700 50,300 31,100 22,400 70,700 38,400 25,900 110,000

30 08070000 95,900 55,900 295,000 132,000 70,600 519,000 194,000 92,300 1,070,000

31 08070200 86,900 42,600 336,000 121,000 54,400 587,000 180,000 72,600 1,200,000

32 08070500 39,800 22,700 184,000 56,600 29,500 398,000 88,300 40,800 947,000

33 08071000 63,000 27,600 367,000 102,000 39,700 880,000 186,000 60,600 2,730,000

34 08071280 49,300 25,500 360,000 64,500 30,600 645,000 89,100 37,300 1,390,000

35 08072300 12,300 6,920 69,300 16,300 8,240 133,000 23,400 10,200 317,000

36 08072730 35,500 15,800 433,000 53,200 21,100 999,000 88,300 29,800 3,000,000

37 08072760 21,700 11,600 118,000 29,100 14,300 235,000 41,700 18,300 516,000

Table 5. Site identification number, station number, and expected peak streamflows for selected annual exceedance probabilities with 

95 percent confidence intervals at 74 selected U.S. Geological Survey streamflow-gaging stations in southeastern Texas.

[ft3/s, cubic feet per second; AEP, annual exceedance probability]
Methods 15

Table 5. Site identification number, station number, and expected peak streamflows for selected annual exceedance probabilities with 

95 percent confidence intervals at 74 selected U.S. Geological Survey streamflow-gaging stations in southeastern Texas.—Continued

[ft3/s, cubic feet per second; AEP, annual exceedance probability]

Site 

identification 

number 

(fig. 2)

Station 

number

Expected peak streamflows for selected AEP with 95 percent confidence intervals

(ft3/s)

1 percent AEP 

(100-year recurrence)

0.5 percent AEP 

(200-year recurrence)

0.2 percent AEP 

(500-year recurrence)

Estimate 

95 percent 

confidence interval Estimate

95 percent 

confidence interval Estimate 

95 percent

 confidence interval

Lower Upper Lower Upper Lower Upper

38 08073500 10,900 8,340 19,200 12,700 9,360 25,300 15,300 10,700 36,300

39 08073600 11,700 8,580 30,300 13,800 9,650 42,400 16,900 11,100 66,200

40 08073700 12,500 9,180 33,500 14,800 10,400 48,200 18,300 11,900 78,100

41 08074000 26,900 20,100 48,700 32,000 23,000 66,000 39,700 26,700 97,800

42 08074020 19,200 13,800 36,300 21,600 14,600 45,000 24,700 15,400 59,200

43 08074150 3,860 3,000 6,130 4,230 3,150 7,330 4,690 3,300 9,220

44 08074250 12,400 9,520 22,700 14,000 10,400 29,500 16,000 11,300 41,600

45 08074500 33,900 26,000 55,000 38,900 28,700 70,200 45,600 31,800 95,800

46 08074800 8,660 6,330 14,700 10,000 7,080 18,500 12,000 8,040 24,700

47 08075000 40,000 32,400 56,300 43,100 33,800 65,500 46,500 35,000 79,300

48 08075400 12,500 9,120 24,900 14,500 10,100 33,200 17,300 11,300 47,900

49 08075500 30,300 21,900 59,000 35,600 24,400 78,900 43,200 27,500 114,000

50 08075730 8,040 6,040 19,000 9,320 6,730 25,600 11,200 7,660 37,800

51 08075770 6,200 4,860 10,200 6,830 5,170 12,500 7,620 5,500 16,200

52 08075780 12,700 6,860 67,100 17,600 8,740 141,000 26,600 11,700 329,000

53 08075900 16,900 12,600 41,100 19,300 13,900 53,600 22,600 15,600 74,400

54 08076000 27,900 19,400 69,300 34,400 22,500 106,000 44,400 27,000 186,000

55 08076180 24,700 14,200 152,000 32,100 17,000 271,000 44,600 21,200 585,000

56 08076500 6,690 5,410 10,900 7,500 5,880 13,600 8,630 6,460 18,100

57 08076700 91,000 50,100 568,000 124,000 61,700 1,130,000 185,000 79,900 2,820,000

58 08077600 32,700 18,600 154,000 43,000 21,600 343,000 61,300 25,800 893,000

59 08110100 31,700 21,100 66,200 38,500 24,500 92,600 48,200 28,800 143,000

60 08111700 84,500 49,800 472,000 109,000 60,500 818,000 149,000 75,700 1,610,000

61 08114000 121,000 109,000 144,000 128,000 114,000 155,000 136,000 120,000 170,000

62 08116650 117,000 98,500 152,000 129,000 107,000 176,000 146,000 117,000 212,000

63 08117500 36,200 27,000 72,300 44,000 31,300 106,000 55,800 37,100 177,000

64 08160400 203,000 118,000 574,000 251,000 137,000 821,000 324,000 164,000 1,290,000

65 08160800 8,460 6,310 16,300 9,670 6,950 21,800 11,300 7,700 32,300

66 08161000 169,000 134,000 245,000 196,000 149,000 305,000 233,000 166,000 402,000

67 08162000 135,000 102,000 233,000 160,000 116,000 314,000 194,000 133,000 460,000

68 08162500 94,100 79,800 118,000 102,000 85,600 133,000 111,000 91,400 156,000

69 08164000 118,000 76,600 275,000 151,000 91,900 419,000 204,000 113,000 717,000

70 08164300 55,700 40,700 93,200 63,300 44,500 119,000 72,900 48,300 163,000

71 08164390 48,500 27,300 152,000 58,500 31,300 215,000 73,000 36,400 331,000

72 08164450 54,500 30,200 347,000 73,000 37,200 647,000 105,000 47,500 1,470,000

73 08175800 363,000 182,000 2,680,000 532,000 240,000 5,980,000 858,000 337,000 15,800,000

74 08176500 240,000 149,000 614,000 320,000 184,000 987,000 454,000 237,000 1,810,000
16 Characterization of Peak Streamflows and Flood Inundations from Hurricane Harvey, 2017

The PeakFQ software uses the three-parameter, logPearson type III (LPIII) probability distribution; the use 

of this distribution for flood analysis is a standard practice 

in the United States (IACWD, 1982). The first and second 

parameters of the LPIII are the arithmetic mean and standard 

deviation, and the third parameter of the LPIII is the sample 

skew. The sample skew was computed for the data for most 

streamflow-gaging station locations by using the “station 

skew” option, which uses the LPIII calculated skew without 

any regional weighting. If a station lacked information on 

natural peak streamflows, the skew calculated by PeakFQ was 

weighted by a regional skew value. The following situations 

required the use of a regionally weighted skew value: (1) the 

period of record was too short for a reliable LPIII fitted 

distribution (typically less than 40 years); (2) the periods 

of record were extensively truncated because of low outlier 

thresholds (for example, a large amount of the peak-flow 

record consisted of nonflood peak events that were removed 

by the multiple Grubbs-Beck low outlier test, leaving a much 

shorter period of record available for analysis); or (3) the 

peak-flow record was visibly affected by upstream dams or 

other streamflow regulation. Regional skew information was 

obtained from Judd and others (1996), who calculated regional 

regression equations for natural stream basins in Texas, thus 

providing a more focused analysis than the regional skew 

values presented in Bulletin 17B. The weighted streamflow 

estimates were then used to determine the AEP associated with 

the August and September 2017 peak streamflow.

Estimated Magnitudes and Flood 

Exceedance Probabilities of Peak 

Streamflows

The number of years of peak streamflow record for the 

74 analyzed streamflow-gaging stations ranged from 18 to 

105, with a mean of 55 years. New record peak streamflows 

were measured at 40 of the 74 USGS streamflow-gaging 

stations (table 3). Peak streamflows ranked second or third 

among the highest peaks of record measured at another 

25 streamflow-gaging stations. At the nine remaining 

streamflow-gaging stations, peak streamflows ranked fourth 

or fifth among the highest peaks of record measured at these 

stations. The AEP estimates for the analyzed streamflowgaging stations ranged from less than 0.2 to 14.0 percent. 

The expected peak streamflows for selected AEPs (1, 0.5, 

and 0.2 percent) with 95 percent confidence intervals at the 

74 streamflow-gaging stations are provided in table 5.

Flood-Inundation Maps

Nineteen flood-inundation maps were created for flooded 

areas in southeastern Texas and a small part of southwestern 

Louisiana (figs. 3–22). Each map presents the areal extent of 

the floodwaters along affected reaches. The HWMs used to 

create the inundation maps and associated information can be 

accessed at the USGS STN website (USGS, 2018b) and are 

provided in Watson and others (2018). Digital datasets of the 

inundation area, modeling boundary, water-depth rasters, and 

final map products are available for download at https://doi.

org/10.5066/F7VH5N3N (Watson and others, 2018). The areas 

covered by the specific flood-inundation maps are described in 

the following sections. All reported peak-stage data obtained 

from USGS streamflow-gaging stations (U.S. Geological 

Survey, 2018a) for use in this report represent final approved 

data unless explicitly stated as provisional data.

Brazos River and Tributaries

The Brazos River is the third longest river in Texas, and 

it flows from the headwaters in Curry County, New Mexico, to 

the Gulf of Mexico near Freeport, Tex. Two flood-inundation 

maps were created to show the areal extent of flooding in 

the Brazos Basin—one flood-inundation map for the upper 

reach and a second flood-inundation map for the lower reach 

(figs. 4–5). 

The upper reach inundation map includes 99 mi of 

the main stem of the Brazos River from Burleigh, Tex., 

downstream to Thompsons, Tex. (fig. 4). This map also 

includes a 43-mi reach of Bessies Creek beginning upstream 

from Pattison, Tex., to the confluence with the Brazos River 

near Fulshear, Tex., and a 9-mi reach of Mill Creek from 

USGS streamflow-gaging station 08111700 Mill Creek near 

Bellville, Tex., to the confluence with the Brazos River. 

Communities along the upper reach of the Brazos River 

include San Felipe, Wallis, Brazos Country, Simonton, Weston 

Lakes, Rosenberg, Richmond, Sugar Land, and Booth, Tex., 

covering parts of Waller, Austin, and Fort Bend Counties. 

The lower reach inundation map is for a 20-mi reach 

of the main stem of the Brazos River from Holiday Lakes, 

Tex., to just upstream from Lake Jackson, Tex. (fig. 5). 

Communities along the lower reach include West Columbia, 

East Columbia, Bailey’s Prairie, Brazoria, and Lake Jackson, 

Tex., in Brazoria County.

A total of 46 surveyed HWMs were used to create the 

inundation maps for the Brazos Basin. The measured depths 

of water at the HWMs ranged from 0 to 8.6 ft above ground, 

and peak water-surface elevations ranged from 19.6 to 283.9 ft 

above NAVD 88. The measured depths of water at the HWMs 

and the surveyed peak water-surface elevation data are 

available for download at https://doi.org/10.5066/F7VH5N3N

(Watson and others, 2018).
Flood-Inundation Maps 17

Figure 4. Flood-inundation map of the upper reach of the Brazos River for the August and September 2017 Hurricane Harvey-related 

flood event in southeastern Texas and southwestern Louisiana.

Dry Creek

Big Creek

Rabbs Bayou

08111700

08111850

08114000

08116400

Burleigh

Booth

San Felipe

Wallis

Sugar Land

Richmond

Fulshear

Orchard

Rosenberg

Thompsons

Brookshire

Pattison

Weston Lakes

Simonton

Monaville

Brazos

Country

FORT BEND

COUNTY

AUSTIN

COUNTY

COLORADO

COUNTY

WHARTON

COUNTY

WALLER

COUNTY HARRIS COUNTY

BRAZORIA

COUNTY

96°10' 96°05' 96°00’ 95°55' 95°50' 95°45' 95°40' 95°35' 95°30'

30°00’

29°55'

29°50'

29°45'

29°40'

29°35'

29°30'

29°25'

Brazos River

Bessies Creek

Mill Creek

EXPLANATION

Inundated area, derived from high-water

mark water-surface elevation and

streamflow-gaging station data

Mapped boundary

Flow direction

08114000

High-water mark

U.S. Geological Survey streamflowgaging station and number

Levee

Mapped area boundary—Restricted by

high-water mark coverage

0 5 10 MILES

0 5 10 KILOMETERS

Base modified from U.S. Geological Survey digital data 

Hydrography and inundated area 1:24,000 scale

Imagery from: Esri World Image Service

Albers Equal Area Projection, Texas Centric Mapping System 

North American Datum of 1983 (2011)
18 Characterization of Peak Streamflows and Flood Inundations from Hurricane Harvey, 2017

Figure 5. Flood-inundation map of the lower reach of the Brazos River for the August and September 2017 Hurricane Harvey-related 

flood event in southeastern Texas and southwestern Louisiana.

BRAZORIA

COUNTY

East

Columbia

Holiday Lakes

Angleton

Bailey's

Prairie

West Columbia

Brazoria Lake

Jackson

95°40' 95°35' 95°30' 95°25'

29°15'

29°10'

29°05'

29°00’

Dry Bayou

Mill Bayo

B

u

razos River

EXPLANATION

Inundated area, derived from high-water

mark water-surface elevation and

streamflow-gaging station data

Mapped boundary

Flow direction

High-water mark

Mapped area boundary—Restricted by

high-water mark coverage

0 2 4 MILES

0 2 4 KILOMETERS

Base modified from U.S. Geological Survey digital data 

Hydrography and inundated area 1:24,000 scale

Imagery from: Esri World Image Service

Albers Equal Area Projection, Texas Centric Mapping System 

North American Datum of 1983 (2011)
Flood-Inundation Maps 19

The USGS operates five streamflow-gaging stations 

on the Brazos River and surrounding tributaries that were 

used in the creation of the inundation maps. The following 

streamflow-gaging stations were used in the creation of the 

maps:

1. Mill Creek near Bellville, Tex. (USGS 08111700): A 

peak stage of 22.49 ft above streamflow-gaging station 

(streamgage) datum (water-surface elevation of 145.31 ft 

above the National Geodetic Vertical Datum of 1929 

[NGVD 29]) was recorded on August 28, 2017; 

2. Brazos River at San Felipe, Tex. (USGS 08111850): A 

peak stage of 129.00 ft above streamgage datum (watersurface elevation of 129.00 ft above NAVD 88) was 

recorded on August 29, 2017; 

3. Brazos River at Richmond, Tex. (USGS 08114000): A 

peak stage of 55.19 ft above streamgage datum (watersurface elevation of 83.13 ft above NGVD 29) was 

recorded on September 1, 2017; 

4. Dry Creek near Rosenberg, Tex. (USGS 08116400): A 

peak stage of 82.53 ft above streamgage datum (watersurface elevation of 82.53 ft above NAVD 88) was 

recorded on August 27, 2017; and

5. Brazos River near Rosharon, Tex. (USGS 08116650): A 

peak stage of 52.65 ft above streamgage datum (watersurface elevation of 52.65 ft above NGVD 29) was 

recorded on August 29, 2017. Note that this station does 

not appear on figures 4 or 5 because it is located between 

the two mapped areas and outside of the extents of the 

two maps, but the peak-stage data were used to create 

the water-surface elevation.

Rainfall totals ranged from about 13 to 39 in. within 

the Brazos Basin for the duration of the event. The highest 

rainfall totals from this one storm event in the Brazos Basin 

are similar to the average annual rainfall for the study area of 

about 45 in. (NOAA, 2014).

Neches River and Tributaries

The headwaters of the Neches River are located in 

northeastern Texas; the Neches River flows approximately 

428 mi to Sabine Lake near the Texas-Louisiana border. 

Several Texas communities are located along a 131-mi reach 

of the Neches River in the counties of Orange, Jasper, Hardin, 

Jefferson, and Tyler, including Beaumont, Evadale, Port 

Neches, and Central Gardens, Tex. Two flood-inundation 

maps were created to show the areal extent of flooding in this 

131-mi reach of the Neches Basin—one flood-inundation map 

for the upper reach and a second flood-inundation map for the 

lower reach (figs. 6–7). The upper reach of the Neches River 

extends from near the confluence with the Angelina River 

to the confluence with Black Creek (fig. 6). The lower reach 

of the Neches River extends from the confluence with Black 

Creek to Sabine Lake (fig. 7).

A total of 33 surveyed HWMs were used to create the 

flood-inundation maps for the Neches Basin. The measured 

depths of water at the HWMs ranged from 0 to 11.6 ft above 

ground, and peak water-surface elevations ranged from 9.2 to 

200.2 ft above NAVD 88.

The USGS operates four streamflow-gaging stations on 

the Neches River that were used in the analysis to create the 

inundation maps: 

1. Neches River near Rockland, Tex. (USGS 08033500): A 

peak stage of 32.08 ft above streamgage datum (watersurface elevation of 120.49 ft above NGVD 29) was 

recorded on September 1, 2017; 

2. Neches River near Town Bluff, Tex. (USGS 08040600): 

A peak stage of 80.70 ft above streamgage datum (watersurface elevation of 80.70 ft above NGVD 29) was 

recorded on August 31, 2017; 

3. Neches River at Evadale, Tex. (USGS 08041000): A 

peak stage of 25.11 ft above streamgage datum (watersurface elevation of 33.36 ft above NGVD 29) was 

recorded on September 2, 2017; and

4. Neches River at Saltwater Barrier at Beaumont, Tex. 

(USGS 08041780): A peak stage of 21.56 ft above 

streamgage datum (water-surface elevation of 21.56 ft 

above NGVD 29) was recorded on September 1, 2017.

Rainfall totals ranged from about 18 to 52 in. within the 

Neches Basin for the duration of the event (NOAA, 2014).

Pine Island Bayou

Pine Island Bayou, a tributary to the Neches River, flows 

south and east intermittently, beginning in northern Liberty 

County, Tex., and continuing through Hardin and Jefferson 

Counties, Tex., before reaching the Neches River in Orange 

County. The extent of the inundation map is a 68-mi reach of 

Pine Island Bayou through the Texas communities of Hull, 

Daisetta, Sour Lake, Nome, Bevil Oaks, Rose Hill Acres, and 

the outskirts of Beaumont (fig. 8). 
20 Characterization of Peak Streamflows and Flood Inundations from Hurricane Harvey, 2017

Figure 6. Flood-inundation map of the upper reach of the Neches River for the August and September 2017 Hurricane Harvey-related 

flood event in southeastern Texas and southwestern Louisiana.

08033500

08040600

B A

Steinhagen Lake

Angelina River

Neches River

Black 

Creek

TYLER COUNTY

HARDIN COUNTY

ANGELINA COUNTY

JASPER COUNTY

Curtis Jasper

94°20' 94°10' 94°00’

31°00’

30°50'

30°40'

30°30'

EXPLANATION

Inundated area, derived from high-water

mark water-surface elevation and

streamflow-gaging station data

Mapped boundary

Flow direction 08040600

High-water mark

U.S. Geological Survey streamflowgaging station and number

Mapped area boundary—Restricted by

high-water mark coverage

2 4 MILES

0 2 4 KILOMETERS

Base modified from U.S. Geological Survey digital data 0

Hydrography and inundated area 1:24,000 scale

Imagery from: Esri World Image Service

Albers Equal Area Projection, Texas Centric Mapping System 

North American Datum of 1983 (2011)
Flood-Inundation Maps 21

Figure 7. Flood-inundation map of the lower reach of the Neches River for the August and September 2017 Hurricane Harvey-related 

flood event in southeastern Texas and southwestern Louisiana.

08041000

EXPLANATION

Inundated area, derived from high-water

mark water-surface elevation and

streamflow-gaging station data

Mapped boundary

Flow direction

High-water mark

U.S. Geological Survey streamflowgaging station and number

Mapped area boundary—Restricted by

high-water mark coverage

2 4 MILES

0 2 4 KILOMETERS

0

J

NEWTON COUNTY

ASPER CO

U

NTY

HARDIN

COUNTY

ORANGE COUNTY

JEFFERSON

COUNTY

Neches River

Black

Creek

Sabine

Lake

08041000

08041780

Evadale

Central

Gardens

Beaumont

Port Neches

94°10' 94°OO’ 93°50'

30°20'

30°10'

30°00’

Base modified from U.S. Geological Survey digital data 

Hydrography and inundated area 1:24,000 scale

Imagery from: Esri World Image Service

Albers Equal Area Projection, Texas Centric Mapping System 

North American Datum of 1983 (2011)
Figure 8. Flood-inundation map of Pine Island Bayou, a tributary to the Neches River, for the August and September 2017 Hurricane Harvey-related fTexas and southwestern Louisiana.

08041700

08041749

Pine Island Bayou

Batiste Creek

Black Creek Boggy Creek

Jackson Creek Long Island Creek

Cotton Creek

Little Pine Island Bayou

Nome

Hull

Batson

Daisetta

Sour Lake

Bevil Oaks

Rose HillAcres

HARDIN COUNTY

LIBERTY COUNTY

JEFFERSON COUNTY

94°40' 94°35' 94°30' 94°25' 94°20' 94°15' 94°10' 

30°15'30°10'30°05'

30°00’

0 0 4 

08041700

EXPLANATION

Inundated area, derived from high-water

mark water-surface elevation andstreamflow-gaging station data

Mapped boundaryFlow direction

High-water markU.S. Geological Survey streamflowgaging station and numberMapped area boundary—Restricted by

high-water mark coverage

Base modified from U.S. Geological Survey digital data Hydrography and inundated area 1:24,000 scaleImagery from: Esri World Image ServiceAlbers Equal Area Projection, Texas Centric Mapping System North American Datum of 1983 (2011)
Flood-Inundation Maps 23

A total of 34 surveyed HWMs in the Pine Island Bayou 

Subbasin were used in the creation of the inundation map. 

The measured depths of water at the HWMs ranged from 0 to 

14.3 ft above ground, and the peak water-surface elevations 

ranged from 16.3 to 79.3 ft above NAVD 88. The USGS 

operates two streamflow-gaging stations on Pine Island Bayou 

that were used in the creation of the inundation map:

1. Pine Island Bayou near Sour Lake, Tex. (USGS

08041700): A peak stage of 39.68 ft above streamgage

datum (water-surface elevation of 39.68 ft above

NGVD 29) was recorded on August 30, 2017; and

2. Pine Island Bayou above BI Pump Plant, Beaumont,

Tex. (USGS 08041749), was inundated during the storm

event, and a HWM peak of 28.97 ft above streamgage

datum (water-surface elevation of 28.13 ft above

NAVD 88) were documented on October 18, 2017. The

date of the peak of 28.13 ft was not recorded because

the station was damaged during the storm event, but the

estimated date of the peak is August 30, 2017.

Rainfall totals ranged from about 24 to 44 in. within the

Pine Island Bayou Subbasin for the duration of the event. The 

highest rainfall totals from this one storm event in the Pine 

Island Bayou Subbasin are similar to the average annual 

rainfall for the study area of about 45 in. (NOAA, 2014).

Sabine River and Tributaries

From its headwaters in Hunt County in north Texas, 

the Sabine River flows approximately 510 mi to its mouth at 

Sabine Lake on the Texas-Louisiana border near the Gulf of 

Mexico. Numerous communities in Jasper, Newton, Orange, 

and Jefferson Counties in Texas and Beauregard, Calcasieu, 

and Cameron Parishes in Louisiana are located along a 131-

mi reach of the Sabine River, including Newton, Tex., Bon 

Wier, Tex., Merryville, La., Kirbyville, Tex., Buna, Tex., 

Deweyville, Tex., Starks, La., Mauriceville, Tex., Vidor, 

Tex., Orange, Tex., West Orange, Tex., Pinehurst, Tex., and 

Bridge City, Tex. Separate flood-inundation maps were created 

to show the areal extent of flooding in the Sabine Basin in 

the upper, middle, and lower reaches of the Sabine River 

(figs. 9–11).

A total of 70 HWMs were surveyed and used to make 

flood-inundation maps for the Sabine Basin. Of these 

70 HWMs, 43 were used to make separate flood-inundation 

maps for either the upper, middle, or lower reaches of the 

Sabine River—13 HWMs in the upper reach, 12 HWMs in 

the middle reach, and 18 HWMs in the lower reach. The 

remaining 27 HWMs were used to make flood-inundation 

maps for tributaries to the Sabine River. For all 70 HWMs in 

the Sabine Basin, the measured depths of water at the HWMs 

ranged from 0 to 7.0 ft above ground, and the peak watersurface elevations associated with the HWMs ranged from 5.7 

to 117.5 ft above NAVD 88. 

The USGS operates four streamflow-gaging stations on 

the Sabine River that were used to create flood-inundation 

maps for the Sabine Basin. One tributary station, Cow Bayou 

near Mauriceville, Tex. (USGS 08031000), was damaged 

during the storm event and not used in the creation of the 

inundation maps. The following streamflow-gaging stations 

were used in the creation of the Sabine Basin flood-inundation 

maps: 

1. Sabine River near Bon Wier, Tex. (USGS 08028500): A 

peak stage of 38.93 ft above streamgage datum (watersurface elevation of 72.35 ft above NGVD 29) was

recorded on September 2, 2017;

2. Big Cow Creek near Newton, Tex. (USGS 08029500): A 

peak stage of 21.08 ft above streamgage datum (watersurface elevation of 155.77 ft above NGVD 29) was

recorded on August 30, 2017;

3. Sabine River near Ruliff, Tex. (USGS 08030500): A 

peak stage of 31.60 ft above streamgage datum (watersurface elevation of 25.68 ft above NGVD 29) was

recorded on September 2, 2017; and

4. Sabine River (at Navy Pier) at Orange, Tex. (USGS

08030540): A peak stage of 7.94 ft above streamgage

datum (water-surface elevation of 7.94 ft above

NAVD 88) was recorded on September 3, 2017.

In the upper reach of the Sabine Basin, the measured

depths of water at the HWMs ranged from 0 to 6.6 ft above 

ground, and the peak water-surface elevations ranged from 

55.7 to 117.5 ft above NAVD 88. Data from one USGS 

streamflow-gaging station (Sabine River near Bon Wier, Tex.) 

were used to help create the inundation map for the upper 

reach (fig. 9). In the middle reach of the Sabine Basin, the 

measured depths of water at the HWMs ranged from 0 to 

7.0 ft above ground, and the peak water-surface elevations 

ranged from 32.0 to 116.2 ft above NAVD 88. In the lower 

reach of the Sabine Basin, the measured depths of water at the 

HWMs ranged from 0 to 7.0 ft above ground, and the peak 

water-surface elevations ranged from 5.7 to 24.4 ft above 

NAVD 88. Data from two USGS streamflow-gaging stations 

were used for the inundation analysis for the lower reach: 

Sabine River near Ruliff, Tex., and Sabine River (at Navy 

Pier) at Orange, Tex.

Rainfall totals ranged from about 19 to 48 in. within 

the Sabine Basin over the duration of the event. The highest 

rainfall totals from this one storm event in the Sabine Basin 

exceed the average annual rainfall for the area of about 45 in. 

(NOAA, 2014).
24 Characterization of Peak Streamflows and Flood Inundations from Hurricane Harvey, 2017

Figure 9. Flood-inundation map of the upper reach of the Sabine River for the August and September 2017 Hurricane Harvey-related 

flood event in southeastern Texas and southwestern Louisiana.

EXPLANATION

Inundated area, derived from high-water

mark water-surface elevation and

streamflow-gaging station data

Mapped boundary

Flow direction

08028500

High-water mark

U.S. Geological Survey streamflowgaging station and number

Mapped area boundary—Restricted by

high-water mark coverage

BEAUREGARD

PARISH

NEWTON

COUNTY

08029500

08028500

Merryville

Big Cow Creek

Quicksand

Creek

Hoosier Creek

Cypress Creek

Sabine River

Newton

93°45' 93°40' 93°35' 93°30'

30°50'

30°45'

30°40'

30°35'

Bon

Wier

0 2.5 5 MILES

0 2.5 5 KILOMETERS

Base modified from U.S. Geological Survey digital data 

Hydrography and inundated area 1:24,000 scale

Imagery from: Esri World Image Service

Albers Equal Area Projection, Texas Centric Mapping System 

North American Datum of 1983 (2011)
Flood-Inundation Maps 25

Figure 10. Flood-inundation map of the middle reach of the Sabine River for the August and September 2017 Hurricane Harvey-related 

flood event in southeastern Texas and southwestern Louisiana.

08030500

EXPLANATION

Inundated area, derived from high-water

mark water-surface elevation and

streamflow-gaging station data

Mapped boundary

Flow direction

High-water mark

U.S. Geological Survey streamflowgaging station and number

Mapped area boundary—Restricted by

high-water mark coverage

JASPER

COUNTY

NEWTON

COUNTY

BEAUREGARD

PARISH

CALCASIEU

PARISH

Cypress

Creek

Slaydons Creek

Little Cypress

Creek

Big Cow

Creek

Nichols Creek

Starks

Sabine River

Buna

Evadale

Deweyville

Kirbyville

08030500

94°00’ 93°55' 93°50' 93°45' 93°40' 93°35'

30°40'

30°35'

30°30'

30°25'

30°20'

0 3 6 MILES

0 3 6 KILOMETERS

Base modified from U.S. Geological Survey digital data 

Hydrography and inundated area 1:24,000 scale

Imagery from: Esri World Image Service

Albers Equal Area Projection, Texas Centric Mapping System 

North American Datum of 1983 (2011)
26 Characterization of Peak Streamflows and Flood Inundations from Hurricane Harvey, 2017

Figure 11. Flood-inundation map of the lower reach of the Sabine River for the August and September 2017 Hurricane Harvey-related 

flood event in southeastern Texas and southwestern Louisiana.

EXPLANATION

Inundated area, derived from high-water

mark water-surface elevation and

streamflow-gaging station data

Mapped boundary

Flow direction

High-water mark

U.S. Geological Survey streamflowgaging station and number

Levee

08030540

CALCASIEU

PARISH

ORANGE

COUNTY

JEFFERSON

COUNTY

CAMERON

PARISH

NEWTON

COUNTY

GULF OF MEXICO

Beaumont

Taylor

Landing

Rose

City

Vidor

Port

Neches

Bridge

City

Orange

West

Orange

Nederland

Pine Forest

Groves

Pinehurst

Port Arthur

Deweyville

Mauriceville

Evadale

Central

Gardens

Sulphur

Vinton Carlyss

Hackberry

Starks

Sabine River

Black

Bayou

Black Bayou

Adams Bayou

Cow Bayou

Neches River

Sabine River

Black

Bayou

Black Bayou

Adams Bayou

Cow Bayou

Neches River

08030500

08030540

94°10' 94°05' 94°00’ 93°55' 93°50' 93°45' 93°40' 93°35' 93°30' 93°25' 93°20'

30°20'

30°15'

30°10'

30°05'

30°00’

29°55'

29°50'

29°45'

0 6 12 MILES

0 6 12 KILOMETERS

Base modified from U.S. Geological Survey digital data 

Hydrography and inundated area 1:24,000 scale

Imagery from: Esri World Image Service

Albers Equal Area Projection, Texas Centric Mapping System 

North American Datum of 1983 (2011)
Flood-Inundation Maps 27

Big Cow Creek

Big Cow Creek, a tributary to the Sabine River, flows 

south towards the Sabine River near Newton and Kirbyville, 

Tex., in Jasper and Newton Counties. The extent of the 

inundation map is a 37-mi reach of Big Cow Creek and its 

tributary, Trout Creek (fig. 12). Eight HWMs were surveyed 

in the Big Cow Creek Basin and used to make the inundation 

map for the area near Kirbyville, Tex., and surrounding areas. 

The measured depths of water at these eight HWMs ranged 

from 1.8 to 6.2 ft above ground, and the peak water-surface 

elevations ranged from 95.4 to 265.9 ft above NAVD 88. Data 

from one USGS streamflow-gaging station were also used to 

make the Big Cow Creek inundation map: Big Cow Creek 

near Newton, Tex. (USGS 08029500), where a peak stage of 

21.08 ft above streamgage datum (water-surface elevation of 

155.77 ft above NGVD 29) was recorded on August 30, 2017.

Cow Bayou

Cow Bayou, a tributary to the Sabine River, flows south 

toward Bridge City, Tex., near Mauriceville, Tex., in Jasper, 

Newton, and Orange Counties. The extent of the inundation 

map is a 23-mi reach of Cow Bayou from its headwaters 

northeast of Evadale, Tex., to State Highway 87 at Bridge City 

near the Sabine River (fig. 13). A total of 19 surveyed HWMs 

in the Cow Bayou Basin were used to make the inundation 

map in the community of Mauriceville and surrounding areas. 

The measured depths of water at the HWMs ranged from 0 

to 6.2 ft above ground, and the peak water-surface elevations 

ranged from 7.6 to 55.5 ft above NAVD 88. One USGS 

streamflow-gaging station within the Cow Bayou Basin, 

Cow Bayou near Mauriceville, Tex. (USGS 08031000), was 

damaged during the storm event, so data from this streamflowgaging station were not available to help make the floodinundation map for Cow Bayou.

San Bernard River

The San Bernard River generally flows southeast through 

Texas from the headwaters near New Ulm, Tex., to its mouth 

on the Gulf of Mexico. Separate inundation maps were 

created to show the areal extent of flooding in the San Bernard 

Coastal Basin in the upper, middle, and lower reaches of the 

river (figs. 14–16). The upper reach includes 20 mi of the San 

Bernard River, extending from northwest of Interstate 10 near 

Sealy, Tex., on the upstream end and continuing downstream 

through the Attwater Prairie National Wildlife Refuge in 

Colorado County, Tex. (fig. 14). The middle reach includes 

46 mi of the San Bernard River, extending from Wallis, Tex., 

in Austin County downstream through East Bernard, Tex., in 

Wharton County and Kendleton, Tex., in Fort Bend County 

(fig. 15). The lower reach includes 33 mi of the San Bernard 

River. In this reach, the San Bernard River flows past Sweeny 

and Brazoria, Tex., in Brazoria County; the downstream 

extent terminates at the San Bernard National Wildlife Refuge 

(fig. 16). 

A total of 34 HWMs surveyed along the San Bernard 

River were used to create flood-inundation maps: 7 HWMs in 

the upper reach, 17 HWMs in the middle reach, and 10 HWMs 

in the lower reach. The measured depths of water at the 

HWMs ranged from 0 to 6.8 ft above ground, and the peak 

water-surface elevations ranged from 8.0 to 253.2 ft above 

NAVD 88. The USGS operates two streamflow-gaging stations 

on the San Bernard River that were used in the creation of the 

inundation maps:

1. San Bernard River near Boling, Tex. (USGS 08117500): 

A peak stage of 43.79 ft above streamgage datum (watersurface elevation of 74.60 ft above NGVD 29) was 

recorded on August 31, 2017; and

2. San Bernard River near Sweeny, Tex. (USGS 08117705): 

A peak stage of 30.16 ft above streamgage datum (watersurface elevation of 30.16 ft above NAVD 88) was 

recorded on September 2, 2017.

Rainfall totals ranged from about 11 to 33 in. within the 

San Bernard Coastal Basin over the duration of the event. The 

highest rainfall totals from this one storm event in the San 

Bernard Coastal Basin represent more than 70 percent of the 

average annual rainfall for the area (about 45 in.) (NOAA, 

2014).
28 Characterization of Peak Streamflows and Flood Inundations from Hurricane Harvey, 2017

Figure 12. Flood-inundation map of Big Cow Creek, a tributary to the Sabine River, for the August and September 2017 Hurricane 

Harvey-related flood event in southeastern Texas and southwestern Louisiana.

EXPLANATION

Inundated area, derived from high-water

mark water-surface elevation and

streamflow-gaging station data

Mapped boundary

Flow direction

High-water mark

U.S. Geological Survey streamflowgaging station and number

Mapped area boundary—Restricted by

high-water mark coverage

08029500

JASPER

COUNTY

NEWTON

COUNTY

08029500

Sabine River

Big Cow Creek

Thickety Creek

Davis Creek

Trout Creek

Melhomes

Creek

Boggy Creek

White Oak

Creek

Robinson Branch

Jasper

Newton

Kirbyville

94°00’ 93°55' 93°50' 93°45' 93°40'

30°55'

30°50'

30°45'

30°40'

0 3 6 MILES

0 3 6 KILOMETERS

Base modified from U.S. Geological Survey digital data 

Hydrography and inundated area 1:24,000 scale

Imagery from: Esri World Image Service

Albers Equal Area Projection, Texas Centric Mapping System 

North American Datum of 1983 (2011)
Flood-Inundation Maps 29

Figure 13. Flood-inundation map of Cow Bayou, a tributary to the Sabine River, for the August and September 2017 Hurricane Harveyrelated flood event in southeastern Texas and southwestern Louisiana.

08031000

EXPLANATION

Inundated area, derived from high-water

mark water-surface elevation and

streamflow-gaging station data

Mapped boundary

Flow direction

High-water mark

U.S. Geological Survey streamflowgaging station and number

Mapped area boundary—Restricted by

high-water mark coverage

JASPER

COUNTY

ORANGE

COUNTY

NEWTON

COUNTY

08031000

Starks

Cow Bayou

Adams Bayou

Cole Creek

Gum Slough

Neches River

Sabine River

Evadale CDP

Deweyville CDP

Mauriceville CDP

Vidor

Orange

Pinehurst

Rose City

Pine Forest

West Orange

Bridge City

94°05' 94°00’ 93°55' 93°50' 93°45' 93°40'

30°25'

30°20'

30°15'

30°10'

30°05'

0 3.5 7 MILES

0 3.5 7 KILOMETERS

87

Base modified from U.S. Geological Survey digital data 

Hydrography and inundated area 1:24,000 scale

Imagery from: Esri World Image Service

Albers Equal Area Projection, Texas Centric Mapping System 

North American Datum of 1983 (2011)
30 Characterization of Peak Streamflows and Flood Inundations from Hurricane Harvey, 2017

Figure 14. Flood-inundation map of the upper reach of the San Bernard River for the August and September 2017 Hurricane Harveyrelated flood event in southeastern Texas and southwestern Louisiana.

EXPLANATION

Inundated area, derived from high-water

mark water-surface elevation and

streamflow-gaging station data

Mapped boundary

Flow direction

High-water mark

Mapped area boundary—Restricted by

high-water mark coverage

Mapped area boundary—Restricted by

lack of ground surface elevation data

AUSTIN

COUNTY

Sealy

COLORADO

COUNTY

§ ̈¦10

ATTWATER PRAIRIE 

NATIONAL WILDLIFE 

REFUGE

WHARTON

COUNTY

San Bernard River

96°20' 96°15' 96°10'

29°50'

29°45'

29°40'

0 2 4 MILES

0 2 4 KILOMETERS

Base modified from U.S. Geological Survey digital data 

Hydrography and inundated area 1:24,000 scale

Imagery from: Esri World Image Service

Albers Equal Area Projection, Texas Centric Mapping System 

North American Datum of 1983 (2011)
Flood-Inundation Maps 31

Figure 15. Flood-inundation map of the middle reach of the San Bernard River for the August and September 2017 Hurricane Harveyrelated flood event in southeastern Texas and southwestern Louisiana.

EXPLANATION

Inundated area, derived from high-water

mark water-surface elevation and

streamflow-gaging station data

Mapped boundary

Flow direction

High-water mark

Mapped area boundary—Restricted by

high-water mark coverage

Mapped area boundary—Restricted by

lack of ground surface elevation data

U.S. Geological Survey streamflow08117500 gaging station and number

08117500

East 

Bernard

AUSTIN

COUNTY

WHARTON

COUNTY

FORT BEND

COUNTY

COLORADO

COUNTY

San Bernard River

Brazos River

Wallis

Kendleton

96°10' 96°05' 96°00’ 95°55' 95°50'

29°40'

29°35'

29°30'

29°25'

29°20'

0 3 6 MILES

0 3 6 KILOMETERS

Base modified from U.S. Geological Survey digital data 

Hydrography and inundated area 1:24,000 scale

Imagery from: Esri World Image Service

Albers Equal Area Projection, Texas Centric Mapping System 

North American Datum of 1983 (2011)
32 Characterization of Peak Streamflows and Flood Inundations from Hurricane Harvey, 2017

Figure 16. Flood-inundation map of the lower reach of the San Bernard River for the August and September 2017 Hurricane Harveyrelated flood event in southeastern Texas and southwestern Louisiana.

08117705

EXPLANATION

Inundated area, derived from high-water

mark water-surface elevation and

streamflow-gaging station data

Mapped boundary

Flow direction

High-water mark

U.S. Geological Survey streamflowgaging station and number

Mapped area boundary—Restricted by

 high-water mark coverage

San Bernard River

Mound

Creek MoundCreek

Brazoria Sweeny

SAN BERNARD 

NATIONAL WILDLIFE 

REFUGE

West Columbia

Brazos RiverBrazos River

BRAZORIA

COUNTY

MATAGORDA

COUNTY

08117705

95°50' 95°45' 95°40' 95°35' 95°30'

29°10'

29°05'

29°00’

28°55'

MILES

0 2.5 5 KILOMETERS

Base modified from U.S. Geological Survey digital data 0 2.5 5

Hydrography and inundated area 1:24,000 scale

Imagery from: Esri World Image Service

Albers Equal Area Projection, Texas Centric Mapping System 

North American Datum of 1983 (2011)
Flood-Inundation Maps 33

San Jacinto River and Tributaries

The San Jacinto River flows south-southeast from 

its headwaters in Grimes and Walker Counties in Texas to 

Galveston Bay and includes the West Fork San Jacinto River 

and the East Fork San Jacinto River. The inundation map of 

the West Fork San Jacinto River is a 36-mi reach of the main 

stem of the San Jacinto River near Conroe, Tex., and includes 

Cypress Creek (53-mi reach), Little Cypress Creek (21-mi 

reach), Willow Creek (6-mi reach), Spring Creek (68-mi 

reach), Walnut Creek (15-mi reach), Panther Branch (11-mi 

reach), Lake Creek (7-mi reach), and Crystal Creek (2-mi 

reach) (fig. 17). The inundation map of the East Fork San 

Jacinto River is a 65-mi reach of the main stem of the San 

Jacinto River near Magnolia, Tex., and includes White Oak 

Creek (9-mi reach), Caney Creek (31-mi reach), Peach Creek 

(19-mi reach), Winters Bayou (33-mi reach), and Luce Bayou 

(9-mi reach) (fig. 18). The 18-mi reach of the San Jacinto 

River from the confluence of the West and East Forks to the 

Lake Houston Dam near Kingwood, Tex., is also included in 

the inundation map (fig. 18).

A total of 106 surveyed HWMs in the entire San Jacinto 

Basin were used in the creation of the two inundation maps. 

The measured depths of water at the HWMs ranged from 0 to 

9.6 ft above ground, and peak water-surface elevations ranged 

from 52.3 to 276.4 ft above NAVD 88.

The USGS operates 22 streamflow-gaging stations on 

the San Jacinto River and its tributaries that were used in the 

creation of the inundation maps:

1. Cypress Creek at Sharp Road near Hockley, Tex. (USGS 

08068700): A peak stage of 170.05 ft above streamgage 

datum (water-surface elevation of 170.05 ft above 

NAVD 88) was recorded on August 28, 2017; 

2. Cypress Creek at Katy-Hockley Road near Hockley, 

Tex. (USGS 08068720): A peak stage of 162.85 ft above 

streamgage datum (water-surface elevation of 162.85 ft 

above NAVD 88) was recorded on August 28, 2017; 

3. Cypress Creek at House-Hahl Road near Cypress, Tex. 

(USGS 08068740): A peak stage of 149.30 ft above 

streamgage datum (water-surface elevation of 149.30 ft 

above NAVD 88) was recorded on August 28, 2017; 

4. Little Cypress Creek near Cypress, Tex. (USGS 

08068780): A peak stage of 161.23 ft above streamgage 

datum (water-surface elevation of 161.23 ft above 

NAVD 88) was recorded on August 28, 2017; 

5. Cypress Creek at Grant Road near Cypress, Tex. (USGS 

08068800): A peak stage of 129.97 ft above streamgage 

datum (water-surface elevation of 129.97 ft above 

NAVD 88) was recorded on August 28, 2017; 

6. Cypress Creek at Stuebner-Airline Road near Westfield, 

Tex. (USGS 08068900): A peak stage of 113.82 ft 

above streamgage datum (water-surface elevation of 

113.82 ft above NAVD 88) was recorded on August 28, 

2017; 

7. Cypress Creek near Westfield, Tex. (USGS 08069000): A 

peak stage of 97.12 ft above streamgage datum (watersurface elevation of 97.12 ft above NAVD 88) was 

recorded on August 28, 2017; 

8. West Fork San Jacinto River near Humble, Tex. (USGS 

08069500): A peak stage of 69.18 ft above streamgage 

datum (water-surface elevation of 69.18 ft above 

NAVD 88) was recorded on August 29, 2017; 

9. Spring Creek near Tomball, Tex. (USGS 08068275): A 

peak stage of 166.38 ft above streamgage datum (watersurface elevation of 166.38 ft above NAVD 88) was 

recorded on August 28, 2017; 

10. Willow Creek near Tomball, Tex. (USGS 08068325): A 

peak stage of 133.87 ft above streamgage datum (watersurface elevation of 133.87 ft above NAVD 88) was 

recorded on August 28, 2017; 

11. Bear Branch at Research Boulevard, The Woodlands, 

Tex. (USGS 08068390): A peak stage of 140.27 ft above 

streamgage datum (water-surface elevation of 140.27 ft 

above NAVD 88) was recorded on August 28, 2017; 

12. Panther Branch at Gosling Road, The Woodlands, Tex. 

(USGS 08068400): A peak stage of 137.49 ft above 

streamgage datum (water-surface elevation of 137.49 ft 

above NAVD 88) was recorded on August 28, 2017; 

13. Panther Branch near Spring, Tex. (USGS 08068450): A 

peak stage of 117.12 ft above streamgage datum (watersurface elevation of 117.12 ft above NAVD 88) was 

recorded on August 28, 2017; 

14. Spring Creek near Spring, Tex. (USGS 08068500): A 

peak stage of 111.52 ft above streamgage datum (watersurface elevation of 111.56 ft above NGVD 29) was 

recorded on August 28, 2017; 

15. West Fork San Jacinto River below Lake Conroe near 

Conroe, Tex. (USGS 08067650): A peak stage of 46.12 ft 

above streamgage datum (water-surface elevation of 

162.18 ft above NGVD 29) was recorded on August 28, 

2017; 

16. Lake Creek at Sendera Ranch Road near Conroe, Tex. 

(USGS 08067920): A peak stage of 150.99 ft above 

streamgage datum (water-surface elevation of 150.99 ft 

above NAVD 88) was recorded on August 28, 2017; 
34 Characterization of Peak Streamflows and Flood Inundations from Hurricane Harvey, 2017

17. West Fork San Jacinto River near Conroe, Tex. (USGS 

08068000): A peak stage of 126.93 ft above streamgage 

datum (water-surface elevation of 126.93 ft above 

NAVD 88) was recorded on August 29, 2017; 

18. West Fork San Jacinto River above Lake Houston near 

Porter, Tex. (USGS 08068090): A peak stage of 94.87 ft 

above streamgage datum (water-surface elevation of 

94.87 ft above NAVD 88) was recorded on August 29, 

2017; 

19. Caney Creek near Splendora, Tex. (USGS 08070500): A 

peak stage of 26.63 ft above streamgage datum (watersurface elevation of 145.07 ft above NGVD 29) was 

recorded on August 28, 2017; 

20. Peach Creek at Splendora, Tex. (USGS 08071000): A 

peak stage of 25.77 ft above streamgage datum (watersurface elevation of 107.38 ft above NGVD 29) was 

recorded on August 28, 2017; 

21. East Fork San Jacinto River near New Caney, Tex. 

(USGS 08070200): A peak stage of 81.15 ft above 

streamgage datum (water-surface elevation of 81.15 ft 

above NAVD 88) was recorded on August 29, 2017; and

22. Luce Bayou above Lake Houston near Huffman, Tex. 

(USGS 08071280): A peak stage of 37.86 ft above 

streamgage datum (water-surface elevation of 77.77 ft 

above NGVD 29) was recorded on August 29, 2017.

Rainfall totals ranged from about 17 to 43 in. within the 

San Jacinto Basin over the duration of the event. The highest 

rainfall totals from this one storm event in the San Jacinto 

Basin approximated the average annual rainfall for the area of 

about 45 in. (NOAA, 2014).
Flood-Inundation Maps 35

Figure 17. Flood-inundation map of the West Fork San Jacinto River and its tributaries for the August and September 2017 Hurricane 

Harvey-related flood event in southeastern Texas and southwestern Louisiana.

Rose Hill

Hockley

Cypress

Security

Decker

Prairie

Woodloch

Stagecoach

Magnolia

Waller

Conroe

Hufsmith

Klein

Westfield

Pine Grove

Bammel

Kohrville

Kingwood

Fostoria

Egypt

Chateau Woods East River

Porter

Williams

Shenandoah

Patton Village

Spring

Tomball

Humble

Oak Ridge North

New Caney

Woodbranch Village Roman Forest

The Woodlands

Splendora

Rose Hill

Hockley

Cypress

Security

Decker

Prairie

Woodloch

Stagecoach

Magnolia

Waller

Conroe

Hufsmith

Klein

Westfield

Pine Grove

Bammel

Kohrville

Kingwood

Fostoria

Egypt

Chateau Woods East River

Porter

Williams

Shenandoah

Patton Village

Spring

Tomball

Humble

Oak Ridge North

New Caney

Woodbranch Village Roman Forest

The Woodlands

Splendora

LIBERTY

GRIMES COUNTY COUNTY

SAN

JACINTO

COUNTY MONTGOMERY

COUNTY

WALLER COUNTY

HARRIS COUNTY

08067650

08067920 08068000

08068090

08069500

08070500

08071000

08068275

08068325

08068390

08068400

08068450

08068500

08068700

08068720

08068740

08068780

08068800

08068900

08069000

95°55' 95°50' 95°45' 95°40' 95°35' 95°30' 95°25' 95°20' 95°15' 95°10'

30°30'

30°25'

30°20'

30°15'

30°10'

30°05'

30°00’

29°55'

29°50'

Spring Creek

Lake Creek

Caney Creek

Peach Creek

Walnut Creek

Willow Creek

Cypress Creek

Little Cypress Creek

Crystal Creek

Bear Branch

West Fork San Jacinto River

White Oak Creek

Panther Branch

Lake

Houston 

Spring Creek

Lake Creek

Caney Creek

Peach Creek

Walnut Creek

Willow Creek

Cypress Creek

Little Cypress Creek

Crystal Creek

Bear Branch

Panther Branch

White Oak Creek

West Fork San Jacinto River

Lake

Houston 

Lake Conroe

08067650

EXPLANATION

Inundated area, derived from high-water

mark water-surface elevation and

streamflow-gaging station data

Mapped boundary

Flow direction

High-water mark

U.S. Geological Survey streamflowgaging station and number

Mapped area boundary—Restricted by

 high-water mark coverage

Levee

0 6 12 MILES

0 6 12 KILOMETERS

Base modified from U.S. Geological Survey digital data 

Hydrography and inundated area 1:24,000 scale

Imagery from: Esri World Image Service

Albers Equal Area Projection, Texas Centric Mapping System 

North American Datum of 1983 (2011)
36 Characterization of Peak Streamflows and Flood Inundations from Hurricane Harvey, 2017

Figure 18. Flood-inundation map of the East Fork San Jacinto River and its tributaries for the August and September 2017 Hurricane 

Harvey-related flood event in southeastern Texas and southwestern Louisiana.

Hufsmith

Klein

W Huffman estfield

Pine Grove

Bammel

Kohrville

Kingwood

Fostoria

Security

Egypt

Chateau Woods East River

Porter

Pumpkin

Williams Snuff Ridge

Shenandoah

Patton Village

Spring

Tomball

Humble

Woodloch

Oak Ridge North

New Caney

Woodbranch Village Roman Forest

The Woodlands

Magnolia

Splendora

Plum Grove

Cleveland

Conroe

Hufsmith

Klein

W Huffman estfield

Pine Grove

Bammel

Kohrville

Kingwood

Fostoria

Security

Egypt

Chateau Woods East River

Porter

Pumpkin

Williams Snuff Ridge

Shenandoah

Patton Village

Spring

Tomball

Humble

Woodloch

Oak Ridge North

New Caney

Woodbranch Village Roman Forest

The Woodlands

Magnolia

Splendora

Plum Grove

Cleveland

Conroe

LIBERTY

COUNTY

SAN

JACINTO

COUNTY

MONTGOMERY

COUNTY

POLK COUNTY

HARRIS COUNTY

WALKER COUNTY

95°35' 95°30' 95°25' 95°20' 95°15' 95°10' 95°05' 95°00’ 94°55' 94°50' 94°45'

30°35'

30°30'

30°25'

30°20'

30°15'

30°10'

30°05'

30°00’

29°55'

West Fork San Jacinto River

White Oak Creek

Bear Branch

Spring Creek

East Fork San Jacinto River

Winters Bayou

Caney Creek

Peach Creek

W

Cypress Creek

illow Creek

Luce Bayou

Panther Branch

West Fork San Jacinto River

White Oak Creek

Bear Branch

Spring Creek

East Fork San Jacinto River

Winters Bayou

Caney Creek

Peach Creek

W

Cypress Creek

illow Creek

Luce Bayou

Panther Branch

Lake Houston

Lake Conroe

0 6 12 MILES

0 6 12 KILOMETERS

08067650

08067920

08068000

08068090

08069500

08070200

08070500

08071000

08071280

08068325

08068390

08068400

08068450

08068500

08068800

08068900

08069000

08067650

EXPLANATION

Inundated area, derived from high-water

mark water-surface elevation and

streamflow-gaging station data

Mapped boundary

Flow direction

High-water mark

U.S. Geological Survey streamflowgaging station and number

Mapped area boundary—Restricted by

 high-water mark coverage

Levee

Base modified from U.S. Geological Survey digital data 

Hydrography and inundated area 1:24,000 scale

Imagery from: Esri World Image Service

Albers Equal Area Projection, Texas Centric Mapping System 

North American Datum of 1983 (2011)
Flood-Inundation Maps 37

Coastal Basins

Harvey made landfall on the northern end of San Jose 

Island about 5 mi east of Rockport, Tex. (fig. 1). The coastal 

watershed basins primarily affected by the flooding that were 

included in this study consist of East and West Matagorda Bay 

Subbasins, East and West San Antonio Bay Subbasins, and 

Aransas Bay Subbasin, all of which are along the southeastern 

coast of Texas (fig. 3; figs. 19–22). Texas coastal areas affected 

by Harvey begin at Matagorda Bay near the San Bernard 

National Wildlife Refuge south of Freeport, Tex., continue 

along the coast through the communities of Matagorda, 

Palacios near Tres Palacios Bay, Port O’Connor, Port Lavaca, 

Austwell, and Rockport, and continue on to the northern side 

of Corpus Christi Bay at Port Aransas and San Jose Island (fig. 

22). The coastal basins in Texas that were affected by Harvey 

contain parts of Matagorda, Jackson, Calhoun, Victoria, 

Refugio, San Patricio, and Aransas Counties.

A total of 129 surveyed HWMs within the selected 

coastal basins in Texas were used to create flood-inundation 

maps (figs. 19–22). Peak stage elevation was recorded at the 

HWMs along stream reaches for the following seven streams: 

Peyton Creek, Big Boggy Creek, Little Boggy Creek, Tres 

Palacios River, East and West Carancahua Creeks, and Keller 

Creek. Peak stage elevation was also measured along the 

Texas coast. Flood-inundation maps were created for the seven 

stream reaches (figs. 19–21) following the same mapping 

methods as described previously for the watershed basins. 

The USGS operates seven streamflow-gaging stations 

within the coastal basins that provided data used to help make 

the inundation maps. Data from the following streamflowgaging stations were used:

1. Colorado River near Bay City, Tex. (USGS 08162500): 

A peak stage of 46.16 ft above streamgage datum (watersurface elevation of 46.16 ft above NGVD 29) was 

recorded on September 2, 2017; 

2. Colorado River near Wadsworth, Tex. (USGS 

08162501): A peak stage of 19.65 ft above streamgage 

datum (water-surface elevation of 26.65 ft above NAVD 

88) was recorded on September 2, 2017 (provisional 

data); 

3. Tres Palacios River near Midfield, Tex. (USGS 

08162600): A peak stage of 30.21 ft above streamgage 

datum (water-surface elevation of 35.59 ft above NGVD 

29) was recorded on August 29, 2017; 

4. Garcitas Creek near Inez, Tex. (USGS 08164600): A 

peak stage of 24.74 ft above streamgage datum (watersurface elevation of 53.90 ft above NGVD 29) was 

recorded on August 27, 2017; 

5. Placedo Creek near Placedo, Tex. (USGS 08164800): A 

peak stage of 29.77 ft above streamgage datum (watersurface elevation of 35.35 ft above NGVD 29) was 

recorded on August 26, 2017; 

6. Guadalupe River near Tivoli, Tex. (USGS 08188800): A 

peak stage of 11.78 ft above streamgage datum (watersurface elevation of 11.82 ft above NGVD 29) was 

recorded on September 1, 2017; and

7. Copano Creek near Refugio, Tex. (USGS 08189200): A 

peak stage of 16.84 ft above streamgage datum (watersurface elevation of 34.09 ft above NGVD 29) was 

recorded on August 29, 2017.

During the 8-day event, rainfall totals ranged from about 

6.67 to 12.54 in. within the West Matagorda Bay Subbasin. 

Within the East Matagorda Bay Subbasin, the rainfall totals 

ranged from about 6.85 to 31.50 in. Within the West San 

Antonio Bay Subbasin, the rainfall totals ranged from about 

12.02 to 17.45 in. Within the East San Antonio Bay Subbasin, 

the rainfall totals ranged from about 7.96 to 16.38 in., and 

within the Aransas Bay Subbasin, the rainfall totals ranged 

from about 11.65 to 33.09 in. (Blake and Zelinsky, 2018). By 

comparison, the mean annual precipitation for the area is about 

45 in. (NOAA, 2014).

East Matagorda Bay Subbasin

Flood-inundation maps were created for several streams 

in the East Matagorda Bay Subbasin in Matagorda County. 

The flood-inundation maps cover a 17-mi reach of Peyton 

Creek, a 16-mi reach of Big Boggy Creek, and a 6-mi reach 

of Little Boggy Creek (fig. 19). A total of 11 surveyed HWMs 

within these reaches were used to create the inundation maps; 

2 HWMs were used for the Little Boggy Creek reach, and 

9 HWMs were used for the Peyton Creek and Big Boggy 

Creek reaches. The measured depths of water at the HWMs 

ranged from 0 to 3.2 ft above ground, and the water-surface 

elevations ranged from 3.3 to 50.7 ft above NAVD 88. 

Ten surveyed HWMs were used to create a floodinundation map for a 21-mi reach of the Tres Palacios River 

within Matagorda County (fig. 20). The measured depths of 

water at the HWMs ranged from 0 to 5.7 ft above ground, and 

the water-surface elevations ranged from 4.9 to 32.8 ft above 

NAVD 88. 

Flood-inundation maps for a 13.5-mi reach of West 

Carancahua Creek, a 14.5-mi reach of East Carancahua Creek, 

and a 9.6-mi reach of Keller Creek within Matagorda, Jackson, 

and Calhoun Counties were created (fig. 21). A total of 

11 surveyed HWMs were used to create the inundation maps 

for these reaches; 7 HWMs were used for the East and West 

Carancahua Creeks, and 4 HWMs were used for Keller Creek. 

The measured depths of water at the HWMs ranged from 0 to 

7.7 ft above ground, and the water-surface elevations ranged 

from 6.7 to 21.7 ft above NAVD 88.
38 Characterization of Peak Streamflows and Flood Inundations from Hurricane Harvey, 2017

Figure 19. Flood-inundation map of Peyton Creek, Big Boggy Creek, and Little Boggy Creek for the August and September 2017 

Hurricane Harvey-related flood event in southeastern Texas and southwestern Louisiana.

EXPLANATION

Inundated area, derived from high-water

mark water-surface elevation and

streamflow-gaging station data

Mapped boundary

Flow direction

High-water mark

Mapped area boundary—Restricted by

 high-water mark coverage

0 2 4 MILES

0 2 4 KILOMETERS

Big Boggy Creek

Live Oak Bayou

Live Oak Bayou

Peyton Creek

Little Boggy

Creek

MATAGORDA

COUNTY

EAST MATAGORDA 

BAY

GULF OF

MEXICO

95°55' 95°50' 95°45'

28°50'

28°45'

Base modified from U.S. Geological Survey digital data 

Hydrography and inundated area 1:24,000 scale

Imagery from: Esri World Image Service

Albers Equal Area Projection, Texas Centric Mapping System 

North American Datum of 1983 (2011)
Flood-Inundation Maps 39

Figure 20. Flood-inundation map of the Tres Palacios River for the August and September 2017 Hurricane Harvey-related flood event in 

southeastern Texas and southwestern Louisiana.

08162500

EXPLANATION

Inundated area, derived from high-water

mark water-surface elevation and

streamflow-gaging station data

Mapped boundary

Flow direction

High-water mark

Mapped area boundary—Restricted by

 high-water mark coverage

Mapped area boundary—Restricted by

lack of ground surface elevation data

U.S. Geological Survey streamflowgaging station and number

Colorado River

Tres Palacios River Tres Palacios River

MATAGORDA

COUNTY

WHARTON

COUNTY

08162600

08162500

Tres 

Palacios

Bay

96°15' 96°10' 96°05'

28°55'

28°50'

28°45'

MILES

0 2 4 KILOMETERS

Base modified from U.S. Geological Survey digital data 0 2 4

Hydrography and inundated area 1:24,000 scale

Imagery from: Esri World Image Service

Albers Equal Area Projection, Texas Centric Mapping System 

North American Datum of 1983 (2011)
40 Characterization of Peak Streamflows and Flood Inundations from Hurricane Harvey, 2017

Figure 21. Flood-inundation map of the East and West Carancahua Creeks and the Keller Creek for the August and September 2017 

Hurricane Harvey-related flood event in southeastern Texas and southwestern Louisiana.

EXPLANATION

Inundated area, derived from high-water

mark water-surface elevation and

streamflow-gaging station data

Mapped boundary

Flow direction

High-water mark

Mapped area boundary—Restricted by 

 lack of ground surface elevation data

West Carancahua Creek

East Carancahua Creek

Keller Creek

West Carancahua Creek

East Carancahua Creek

Keller Creek

Carancahua 

Bay

Keller 

Bay

Lavaca 

Bay

Tres

Palacios

Bay

Carancahua 

Bay

Keller 

Bay

Lavaca 

Bay

Tres

Palacios

Bay

CALHOUN

COUNTY

MATAGORDA

COUNTY

JACKSON

COUNTY

CALHOUN

COUNTY

96°35' 96°30' 96°25' 96°20' 96°15'

28°55'

28°50'

28°45'

28°40'

0 3 6 MILES

0 3 6 KILOMETERS

Base modified from U.S. Geological Survey digital data 

Hydrography and inundated area 1:24,000 scale

Imagery from: Esri World Image Service

Albers Equal Area Projection, Texas Centric Mapping System 

North American Datum of 1983 (2011)
Figure 22. Flood-inundation map from coastal water-surface elevation data for the August and September 2017 Hurricane Harvey-related flood evensouthwestern Louisiana.

35

97° 96°

29°28°

San Jose 

Island

DEWITT

COUNTY

GOLIAD

COUNTY

VICTORIA

COUNTY

JACKSON

COUNTY

REFUGIO

COUNTY

SAN PATRICIO

COUNTY

CALHOUN

COUNTY

CALHOUN COUNTY ARANSAS COUNTY

MATAGORDA

COUNTY

BEE

COUNTY

BRAZORIA 

NUECES

COUNTY

DEWITT

COUNTY

GOLIAD

COUNTY

VICTORIA

COUNTY

JACKSON

COUNTY

REFUGIO

COUNTY

SAN PATRICIO

COUNTY

CALHOUN

COUNTY

CALHOUN COUNTY ARANSAS COUNTY

MATAGORDA

COUNTY

BEE

COUNTY

BRAZORIA 

NUECES

COUNTY

08189200

08188800

08164600

08164800

08162600

08162501

Port O'Connor

Austwell

Port Lavaca

Rockport

Port Aransas

Palacios Matagorda

Tivoli

Corpus Christi

GULF OF MEXICO

Co

lo

rado

River

Copano Creek

Guadalupe River Guadalupe River

Garcitas Creek Garcitas Creek

Placedo Creek Placedo Creek

Tres

Palacios

Tres

Palacios River Colorado

River

Copano Creek

Guadalupe River Guadalupe River Guadalupe River

Garcitas Creek Garcitas Creek Garcitas Creek

Placedo Creek Placedo Creek Placedo Creek

Tres

Palacios

Tres

Palacios

Tres

Palacios River

Matagorda Bay

San Antonio Bay

Corpus Christi Bay

EXPLANATION

Mapped boundaryHigh-water markU.S. Geological Survey streamflow08162600 gaging station and number

Mapped area boundary—Restricted by

high-water mark coverage

Flood peaks—Water-surface elevation, in feet. Datum is 

North American Vertical Datum of 1988

0 to 22.1 to 44.1 to 66.1 to 8

8.1 to 1010.1 to 1212.1 to 1414.1 to 16

16.1 to 2020.1 to 2424.1 to 2828.1 to 34.4

Base modified from U.S. Geological Survey digital dataHydrography and water-surface elevation 1:24,000 scale Imagery from: Esri World Image ServiceAlbers Equal Area Projection, Texas Centric Mapping System North American Datum of 1983 (2011)

0 0 
42 Characterization of Peak Streamflows and Flood Inundations from Hurricane Harvey, 2017

Peak Water-Surface Elevations for Coastal Areas

The coastal water-surface elevation map for the 135-

mi coastline of Texas including the counties of Matagorda, 

Jackson, Calhoun, Victoria, Refugio, San Patricio, and Aransas 

is shown in figure 22. A total of 97 surveyed HWMs and 

6 USGS streamflow-gaging stations were used to create the 

coastal water-surface elevation map. This map shows the watersurface elevation, generated from topo to raster interpolation 

methods, from peak stage recorded during the flood event. The 

mapped boundary was kept in close proximity to the location 

of surveyed HWMs. The measured depths of water at the 

HWMs ranged from 0 to 4.8 ft above ground, and the watersurface elevations ranged from 2.7 ft above NAVD 88 near Port 

O’Connor to 34.4 ft above NAVD 88 along State Highway 35 

near Tivoli. 

Flood Damages

More than 300,000 structures and at least 500,000 cars 

were flooded as a result of Harvey (NOAA, 2018c). The most 

current (2018) damage estimate from Harvey is $125 billion, 

making it the second costliest event behind Hurricane Katrina 

in 2005 when adjusted for inflation (NOAA, 2018c). Harvey 

ranks as the deadliest hurricane to hit the United States since 

Hurricane Sandy in 2012. Harvey is responsible for at least 

68 direct fatalities, all in Texas. Direct fatalities are those 

that are a direct result of the tropical storm such as lightning, 

wind-related collapses, and drowning from storm surge, rough 

seas, rip currents, and freshwater flooding. All but three of 

the fatalities were a result of freshwater flooding; none of the 

fatalities resulted from storm surge. In addition to the 68 direct 

fatalities, an additional 35 people died as a result of indirect 

causes such as electrocution, vehicle crashes, and lack of 

medical services (NOAA, 2018c).

Summary

Hurricane Harvey made landfall near Rockport, Texas, on 

August 25 as a Category 4 hurricane with wind gusts exceeding 

150 miles per hour. As Harvey moved inland, the forward 

motion of the storm slowed down and produced tremendous 

rainfall amounts to southeastern Texas, with 8-day rainfall 

amounts exceeding 60 inches in some locations, which is about 

15 inches more than average annual amounts of rainfall for 

eastern Texas and the Texas coast. Historic flooding occurred in 

Texas as a result of the widespread, heavy rainfall. 

In the immediate aftermath of the Harvey-related 

flood event, the U.S. Geological Survey (USGS) and the 

Federal Emergency Management Agency (FEMA) initiated 

a cooperative study to evaluate the magnitude of the flood, 

determine the probability of occurrence, and map the extent 

of the flood in Texas. Seventy-four USGS streamflow-gaging 

stations in Texas with at least 15 years of record and no 

large data gaps in the period of record had a 2017 annual 

peak streamflow related to Harvey ranking in the top five 

of all annual peaks for each given station. New record peak 

streamflows were recorded at 40 of the 74 USGS streamflowgaging stations. The number of years of peak streamflow 

record for the 74 analyzed streamflow-gaging stations 

ranged from 18 to 105, with a mean of 55 years. The annual 

exceedance probability estimates for the analyzed streamflowgaging stations ranged from less than 0.2 to 14.0 percent. 

During the weeks following the event, USGS field crews 

surveyed 2,123 high-water marks to obtain water-surface 

elevations. In some locations, several water-surface elevations 

were averaged to obtain 1 water-surface elevation, resulting 

in 1,258 water-surface elevations. Some of these high-water 

marks were used, along with peak-stage data from USGS 

streamflow-gaging stations, to create 19 inundation maps of 

the extent of the maximum depth of the flooding.

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For more information about this publication, contact

Director, Texas Water Science Center

U.S. Geological Survey

1505 Ferguson Lane

Austin, TX 78754–4501 

For additional information visit https://tx.usgs.gov/.

Publishing support provided by

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Watson and others—Characterization of Peak Streamflows and Flood Inundations from Hurricane Harvey, 2017—SIR 2018–5070

ISSN 2328-0328 (online)

https://doi.org/10.3133/sir20185070