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www.cerf-jcr.org

Beach Erosion along the Northeast Texas Coast

Young Hyun Park{ and Billy L. Edge{*

{BK21 SIR Group

Department of Civil and Environmental

EngineeringSeoul National University

South Korea

{Haynes Coastal Engineering Laboratory

Zachry Department of Civil Engineering

Texas A&M UniversityCollege Station, TX 77843-3136, U.S.A.

[email protected]

ABSTRACT

PARK, Y.H. and EDGE, B.L., 2011. Beach erosion along the northeast Texas coast. Journal of Coastal Research, 27(3),502514. West Palm Beach (Florida), ISSN 0749-0208.

Some areas of the Texas coast along the Gulf of Mexico are stabilized by beach nourishment or artificial protections, butthe northeast Texas coast has been damaged and changed by short- and long-period erosion. The berm or dune that canact as protection from wave activities rarely exists, and mild, sloping beaches increase the potential of erosion in thestudy area. The upper Texas coast was monitored by Texas A&M University between 1999 and 2005. The measuredbeach profiles showed the morphological short- and long-period changes by overwash, and critical erosion was observed,especially by the landfall of hurricane Rita in 2005. The suspected causes of severe erosion were analyzed by comparingdune heights and beach widths, and it was found that overwash was one of the major factors causing erosion of the

shoreline in the area. When storms made landfall in neighboring regions, such as southern Texas, Louisiana, Mississippi,

and Alabama, overwash by long-period waves of remote storms was observed during the beach surveys. Overwash byremote storms could not be ignored, and it was an important contributor to continued beach erosion in the study area.Erosion caused by direct landfall of storms had significant effects on long-period erosion as well.

ADDITIONAL INDEX WORDS: Remote storm, storm, hurricane, beach erosion, overwash, short-period, long-period,Texas.

INTRODUCTION

The northeast Texas coast has experienced extreme erosion

and has retreated for decades, though the area was directly

impacted by landfalls of only two storms from 1991 to 2005

(Tables 1 and 2). The area has been studied for decades, and

overwash is strongly suspected as the main cause of erosion.Overwash is the phenomenon of sediment transport with

overtopping, defined as a form of coastal flooding that can

move sediment landward, and it is a precursor to barrier

breaching, as described by Donnellyet al. (2004). Leatherman

(1983) said that Atlantic coast barriers whose widths are less

than200 m suffer overwash frequently. Because our study area

was located in the Gulf of Mexico, his conclusions could not be

directly applied. However, because the beach in the study area

was quite narrow and flat with small dunes, its morphological

characteristics resulted in severe erosion during even minor

overwash events.

If overwash wereprevented by some means, erosion would be

reduced.However, the shoreline and the offshore area continue

to be eroded. The offshore area, which is composed of finesediments commonly found on the northeast Texas coast, is

eroded constantly. The shoreline continues to be eroded during

major storms, and much sediment is transported seaward.

These are general beach processes that cause cross-shore

erosion. Because cross-shore sediment transport was dominant

and several overwash events were observed in the study area,

overwash by storms was investigated as a main cause of

erosion. The study area was directly and remotely affected by

storms in the Gulf of Mexico.

Overwash generally happens at the landfall of a storm, but

only two direct landfalls occurred in the study area between1991 and 2005: landfalls of Tropical Storm Ivan (2004) and

Hurricane Rita (2005) occurred at the end of the period.

However, because the continuous beach erosion problem by

overwash could not be explained by these direct landfalls, we

needed to focus on other causes. Overwash induced by remote

storms was frequently observed during beach surveys, and

remote storms were believed to be one of the main causes of

overwash in the study area. The objective of this study was to

investigate overwash of remote storms by analyzing multiple

characteristics of beach erosion in this area.

In this article, the geological and hydrodynamic character-

istics of the study area are described, followed by an

explanation of the methods of short- and long-period beach

surveys. Analyses are presented of beach erosion based on

short- and long-period measurements, beach erosion by direct

landfall of storms and remote storms, and overwash deter-

mined by comparing dune andbeach width with beach erosion.

These sections are followed by our conclusions.

CHARACTERISTICS OF THE STUDY AREA

The study area ranged from High Island to Sabine Pass near

the border between Texas and Louisiana, shown in Figure 1.

DOI: 10.2112/JCOASTRES-D-09-00042.1 received 19 April 2009;accepted in revision 24 February 2010.

* Corresponding author Coastal Education & Research Foundation 2011

Journal of Coastal Research 27 3 502514 West Palm Beach, Florida May 2011
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The shallow water is turbid from suspended sediment from the

Mississippi and Atchafalaya rivers; this fine sediment changes

the coastline and coastal environment in this area by

suspension, transport, erosion, and deposition. The study area

is located on the Louisiana-Texas continental shelf. The

maximum and minimum widths of the continental shelf are

200 km at the Louisiana border and 30 km in south Texas,respectively. The depth at the seaward boundary of the shelf is

180m, and theshelf forms a mild slope from theshoreline. The

study area is affected by wind and waves mostly from the

southeast, but their strength is not enough to cause critical

erosion except during severe storms.

Geologically thin barrier beach sands overlying the Pleisto-

cene headland (Beaumont Formation) occur between Sabine

Pass and High Island. The area near Sea Rim State Park is an

anomalous sandy beach that has been attributed to sand derived

locally from underlying Pleistocene river deposits (Morton,

1979) and/or possibly the convergence of littoral cells. The

shoreface between the McFadden National Wildlife Refuge to

the west of Sea Rim State Park and High Island consists of a

headland that is composed of late Pleistocene fluvial-deltaic

deposits. Beaches in this region are narrow and are often

covered by shell pads that migrate along the beach, depending

on wave heights and sedimenttransport direction. The foreshore

is steep and berm crests are well defined where thick shell pads

are present. Nevertheless, many areas of the Beaumont

Formation are exposed on the surface of the shoreface.

Texas Highway 87 along the northeast Texas coast was

destroyed by Hurricane Jerry (Category 1) in 1989, and it has

remained without any restoration. Direct impacts by storms

were rare in the study area, and only two landfalls of storms

occurred during the monitoring surveys: Tropical Storm Ivan(2004) and Hurricane Rita (2005).

The U.S. Army Corps of Engineers (Waters, 2003) conducted

a shoreline erosioncontrol demonstration project, which was

located about 3.6km away from theeast endof theshort-period

study area. Waters (2003) showed that the average wave

heights were estimated to be between 0.76 and 0.91 m in

summer and between 1.2 and 1.4 m in winter. The mean tide

range was 0.39 m. We also surveyed the control project area

and observed that the erosion control demonstration project

created a relatively stable area with the long-period rate of

retreat of about 1.5 m/y. This value was much less than the

valueof Morton (1997)of 3.7m/yand therateof retreat of3.5 m/

y from this study along all survey lines.

In this study, beachsampleswere collected from dune, beach

face, and subaqueous areas from the north Galveston jetty to

Sabine Pass, and the median grain size (D50) was measured.

The results are presented in Table 3; the presence of clay was

observed in almosthalfof the sites(8 of 19). Sand samples could

Table 1. Tropical cyclones in the period 20002005 (NOAA, 2006) near the northeast Texas coast.

Name Class Landfall Date

Data

Peak Wind (km/h) Pressure (mb)

Rita Hurricane, Cat. 3 Port Arthur, Texas 9/24/05 193 937

Katrina Hurricane, Cat. 3 Southeast Louisiana 8/29/05 201 920

Ivan (landfall twice) Hurricane, Cat. 3 Alabama 9/16/04 (first landfall) 193 943

Tropical storm Port Arthur, Texas 9/23/04 (second

landfall)

65 1003

Bill Tropical storm Southeast Louisiana 6/30/03 52 997

Claudette Hurricane, Cat. 1 Port OConnor, Texas 7/15/03 96 981

Grace Tropical storm Between Port OConnor and

Freeport, Texas

8/31/03 65 1007

Fay Tropical storm Palacios, Texas 9/06/02 93 998

Lili Hurricane, Cat. 2 South central Louisiana 10/03/02 148 963

Table 2. Landfalls of storms around the upper Texas coast from 1991 to 2005.

North Texas South Texas Louisiana Mississippi Alabama Total

1991 0

1992 1 1

1993 1 1

1994 1 1 2

1995 1 1 1 3

1996 0

1997 1 1

1998 2 1 1 1 5

1999 1 1

2000 1 1

2001 1 1 2

2002 2 1 1 1 5

2003 2 1 3

2004 1 1 1 3

2005 1 2 2 5

Total 2 10 6 5 10 33

Beach Erosion along the Northeast Texas Coast 503

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not be collected from Sea Rim State Park to Sabine Pass

because the recently deposited fine-grained deposits were too

soft and deep to walk on. The average median grain sizes were

0.171 mm, 0.165 mm, and 0.155 mm at dunes, beach faces, and

surf zones, respectively.

A thin layer of sand overlay the clay, and both Pleistocene

and Holocene clays were exposed due to a deficiency of sand in

most of the area. Substantial wave damping was observed in

some locations with an aqueous muddy bottom. Tuttle (2000)

studied the impact of these aqueous muddy bottoms in

Jefferson County and found that waves are damped quicklyin these areas. Tuttle noted that the density of the mud is

closely related to viscosity, with denser mud showing higher

viscosity. Zhang and Zhao (1999) found that dense and viscous

mud responds more slowly in wave action and causes wave

energy dissipation. The exposed mud of Pleistocene and

Holocene periods by erosion of veneer sand along the study

area is shown in Figure 2. We believe that wave heights in the

study area were reduced due to viscous damping by the muddy

bottom.

METHODS

To assess beach erosion due to remote storms, beach profiles

in fixed locations and wave data were analyzed. Time-series

surveys were conducted for the beach profiles, and wave data

were obtained from the National Data Buoy Center (NDBC).

Beach erosion was analyzed using changes in beach profiles,

dunes, and beach widths. The profiles were measured using

real time kinematicdifferential global positioning system

equipment with approximately 2-cm accuracy in vertical andhorizontal directions, but the resolution varied with the

distance from the base station. A dual frequency echosounder

was used in the measurement of water depth.

Beach profiles along the study area were measured by our

research team from 1999 to 2005. There were initially 156

survey lines betweenHigh Island and SabinePass, but only the

even-numbered lines were measured throughout the duration

of the survey. The distance from the first to the last line was

about 31 km, and the interval between each line was

Figure 1. Aerial photo of the study area and the location of cross-shore survey lines along the northeast Texas coast (Google Earth, 2009).

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approximately 400 m. The coordinates of several survey lines

and the survey periods are given in Table 4.

The surveys were conducted to monitor short- and long-

period beach changes. The long-period surveys were conducted

eachseasonbetween 1999and 2002. Theshort-periodintensive

surveys were repeated seven times for lines 126 and 128between 2004 and2005 by Park (2006). Lines126 and 128were

selected due to high potential for overwash. Each beach profile

was measured from the dune to the closure depth at a distance

of 600 m offshore. The measured beach profiles were analyzed

in short and long periods separately, and the data were

analyzed by comparing changes in dune and in beach width.

COASTAL PROCESSES

Sand Budget

Morang (2006) discussed sediment transport in the study

area as part of a study to determine options for long-period

stabilization of the shoreline from Sabine River to San LouisPass, southwest of Galveston. He noted that 75% of sediment

movement is in the cross-shore direction and only 25% of sand

moves alongshore. In the cross-shore movement, 40% of eroded

sand moves offshore and 35% of sand is eroded and moved by

overwash. Our study area does not have a balance alongshore

in sand budget either. Sediment transport by overwash was

directly related to the intensity of the storm, waves, and storm

surge level, andan increase of overwash might be a main cause

of permanent shoreline recession.

Long-Period Changes

Morton (1979) concluded that three factorsdeficit in

sediment, sea level rise, and storm activitiescontributed to

long-period changes along the southeast Texas coast. Morton

(1997) studied beach erosion in the area between Sabine Passand Galveston Island and showed therateof retreat depictedin

Figure 3. He found that the maximum rate of retreat (9.8 m/y)

was observed between Sabine Pass and Sea Rim State Park

over 23 years (1974 to 1996). The average rate of retreat was

3.7 m/y in the study area between 1974 and 1996 (Morton,

1997). Oursurveys showed that theaverage rate of retreat was

3.5m/y at L126 and L128 before thelandfall of HurricaneRita,

but it sharply increased to 5.2 m/y due to the hurricanes

impact. It seemed that the rate of retreat almost kept constant

between 1974 and 1996; the study area has been suffering the

retreat of the shoreline for a long time.

Short-Period Changes

The data for short-period changes were collected and

analyzed from 2004 to 2005. The beach profiles of L124 and

L126 are shown in Figure 4. Only two storms made landfall in

the study area during this period (Table 1), and the major

short-period changes occurred from the impact of these two

storms. The average rate of retreat was 5.2 m/y between 1999

and 2005 in the study area, which includes the landfall of

Hurricane Rita and long-period waves generated by Hurricane

Katrina. These storms caused considerable retreat of the

Table 3. The measured sand size along the upper Texas coast (from north Galveston Island) in 2003.

Coordinate Location D50 (mm) Coordinate Location D50 (mm)

29u24917.0500 N, 94u42921.2360 W Berm 0.164 29u25942.0340 N, 94u40930.3300 W Berm 0.151

Beach face 0.141 Beach face 0.150

Surf zone 0.130 Surf zone 0.152












Surf zone 0.159 Surf zone Clay



Surf zone Clay Surf zone Clay


Beach face Clay Beach face 0.152

Surf zone Clay Surf zone Clay



Surf zone Clay Surf zone 0.123


Beach face Clay Beach face 0.120

Surf zone Clay Surf zone 0.111

29u40954.4950 N, 93u58957.4080 W Berm 0.145

Beach face 0.129

Surf zone Clay



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shoreline in 2005. Hurricane Rita was responsible for the

retreat of 15 m at L126 and L128 during landfall.

The measured profiles indicated that some eroded sediments

were transported and deposited behind the backshore and the

rest were moved and deposited at the toeof the beach face. The

ratio of landward and seaward transport by overwash was

studied by Park (2006), who showed that the ratio of landward

transport increased for steeper slopes, higher wave heights,

and longer wave periods. Morton and Paine (1985) estimated

that the sand volume of overwash caused by Hurricane Alicia

(1983), a Category 3 storm at landfall, was about 12% of the

total volume of eroded sand around the study area. However,

Figure 2. The exposed mud bottom along the northeast Texas coast.

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Stone et al. (1996) reported that 95%99% of sand eroded by

Hurricane Opal, which made landfall as a Category 4 storm in

Florida, was deposited on the dune and backshore. The sand

deposited behind the dune by overwash does not easily return

to its pre-overwash position (such as the top of the dune, beach

face, etc.), and it might be a permanent loss of shoreline.

The surveyed beach profiles shown in Figure 4 showed that

the profile accreted in winter and eroded in summer between

February 16, 2004, and September 21, 2005. This seasonal

pattern was opposite to the general summer/winter beach

pattern that maintained the shape of the beach by repeatingseasonal accretion and erosion in most of the stable beaches.

Though the average wave height in the winter was almost 50%

higher than in thesummer,the seasonal cycle wascollapsed by

remote and direct impacts of storms along the upper Gulf of

Mexico in summer.

The erosion control project of the U.S. Army Corps of

Engineers was tested with different dune configurations

separated by six geotextile groins since 2004. The dunes

between the groins were composed of sediments of multiple

grain sizes, including clay fill. The site was located between

L128 and L156, 3.6 km away from L128. The measured beach

profiles are shown in Figure 5. These were explained in detail

by Waters (2003). Waters mentioned some success of this

demonstration project by showing deposition of sediment

between the groins and the test dunes. The beach width was

much less than the 200 m of stable beach width on the Atlantic

coast suggested by Leatherman (1983), but it seemed that this

area was becoming stable by accretion based on the measured

profiles.

In the area of the erosion control demonstration project,

shoreline retreat was about 7 m by the impact of Hurricane

Rita, but it returned to its previous position after a year.

Morton, Paine, and Gibeaut (1994) mentioned the recovery

processes ofthe erodedbeachby storms; 50m and 1.5 m are the

minimum beach width and elevation for recovery processes,respectively. Though more data were needed for comparison,

their reference values for beach stability seemed to match with

our survey results in the study area.

IMPACT OF STORMS

Because it is difficult to predict landfall of storms with high

accuracy 48 hours prior to landfall, many past surveys had

trouble getting good-quality data for the impact of storms, due

to distance between the survey area and the eye of the storm,

the interval of surveys at landfall of the storm, etc. During the

monitoring of long-period profile changes between 1999 and

2005, only two landfalls were made in the study area. Tropical

Storm Ivan and Hurricane Rita made landfall in 2004 and

Table 4. The coordinates of survey lines along the upper Texas coast.

Name Latitude Longitude Survey Period

L1 29u33921.0380 N 94u22915.5540 W Fall 1999Spring 2002


L126 29u38952.8150 N 94u07957.8870 W Fall 1999Sept. 2005

L128 29u38957.9220 N 94u07944.1220 W Fall 1999Sept. 2005


Waters site 29u39927.650 N 94u06912.880 W Dec. 2004Aug. 2006

Figure 3. Average long-period shoreline change from 1974 to 1996 (Morton, 1997).



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2005, respectively, and the latter caused extreme damage to

inland areas as well as along the coastal study area. Overwash

by remote storms was observed in the study area at landfall of

Hurricanes Ivan and Katrina. Wave data were obtained from

Station 42035 by the NDBC, and long-period waves by remotestorms are presented in Figure 6. Data losses by the severe

impact of Hurricane Rita are also shown in the figure.

Hurricane Ivan

Hurricane Ivan made landfall twice. The first landfall was

made with a wind speed of 193 km/h (Category 3 on the Saffir-

Simpson scale) in Alabama on September 16, 2004. The storm

moved inland, turned to the Atlantic Ocean, and then curved

clockwise. It reentered the Gulf of Mexico and traveled

westward. Its second landfall was made with a wind speed of

74 km/h (tropical storm)at Sabine Pass on September 24,2004.

During both landfalls, beacherosion occurred in thestudyarea

as a result of overwash. The first overwash occurred by long-

period waves from the remote Hurricane Ivan, and the secondwas caused by landfall of Tropical Storm Ivan with higher

surge and shorter-period waves.

Hurricane Katrina

Hurricane Katrina produced the maximum wind speed of

282 km/h (Category 5) in the Gulf of Mexico and was 201 km/h

(Category 3) at landfall in Louisiana on August 29, 2005.

Though thestudyarea was located about 450km away from its

landfall, a massiveoverwash fan and inundation by long-period

waves were observed in the study area at landfall. Overwash

caused by Hurricane Katrina in the study area is shown in

Figure 7.

Hurricane Rita

Hurricane Rita was another extreme storm in the Gulf of

Mexico, occurring within a month of Hurricane Katrina. Rita

made landfallwitha wind speedof 193 km/h(Category 3) at the

Texas-Louisiana border on September 24, 2005. The beach

profile measurements were conducted 3 days before landfall on

September 21,2005, and 5 days after landfall on September 29,

2005. The survey results provide good references for research

in cross-shore beach erosion caused only by a storm, because

the survey was conducted immediately before and after land-

fall of thestorm. Thebeach and inland area near the study site

were devastated, and civilian access was prohibited for several

weeks. The eroded sand was transported and depositedbehind the dune. The retreat of the beach face was about

15 m, and 33.8 m3/m of sand was eroded by Hurricane Rita.

Dune heights were reduced by more than 1 m, or 50% of their

original heights during landfall. The two photos in Figure 8

were taken at each profile measurement: photo A was taken

3 days before landfall, and photo B was taken 5 days after

landfall. In each photo, landward and seaward sides are right

Figure 4. Shoreline changes, including landfall of Hurricane Rita, during

1999 and 2005.

Figure 5. Beach profiles measured in the control study area (Waters, 2003).

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and left, respectively. Though the photos were taken at the

same location, they seemed to be different places due to the

complete removal of small dunes, vegetation, and sand by

Hurricane Rita and because of the presence of the exposed clay

bottom by erosion.

Remote Storms

Because overwash was generated mainly by strong wave

activities and/or storm surges, landfall of storms in areas and

states surrounding the study area, such as south Texas,

Figure 6. Wave data for Tropical Storm Ivan (2004) and Hurricanes Katrina (2005) and Rita (2005) from NDBC buoy 42035 off the Texas coast.



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Louisiana, Mississippi, and Alabama, were also included in the

investigation. There were33 landfalls in these states from1991

through 2005, as shown in Table 2. Two direct landfalls were

made by Tropical Storm Ivan in 2004 and Hurricane Rita in

2005, as previously mentioned. This constituted only 6.1% of

the 33 landfalls; almost 50% of landfalls were made in south

Texas and Louisiana, which were adjacent to the study area.

Though there was no direct landfall of storms during 1991 and

2003, erosionand damage fromoverwash wereobserved during

beach surveys. When Hurricane Katrina made landfall in

Louisiana, some important evidence of overwash caused by a

remote storm was found in the study area. It is believed that

Figure 7. Overwash caused by remote impact of Hurricane Katrina (2005) in the study area.

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the study area continued to erode by overwash caused by

remote as well as direct landfalls.

Though only five hurricanes were stronger than or equal

to Category 3 between 1991 and 2003 in the Gulf of

Mexico, three of these hurricanes were recorded in 2004 and

2005. When we considered that 15 and 18 landfalls were

made during the periods of 19912000 and 20012005,

respectively, it seemed that the frequency and severity of

storm activity was rapidly increasing after 2001, possibly due

to climate change.

Figure 8. The impact of Hurricane Rita at L126 and L128 in 2005, (A) 3 d before landfall, on September 21, 2005, and (B) 5 d after landfall, on September

29, 2005.



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OVERWASH

The long-period surveys were conducted to analyze the

characteristics of erosion along the northeast Texas coastbetween 1999 and 2002. Seventy-eight survey lines were

carried out on the 31-km-long coastline. The elevations of

dunes or backshore rarely exceeded 2 m above mean sea level

(MSL) along the shoreline. The lowest dune or backshore was

located betweenlines 126 and 128, and thisarea was frequently

overwashed.

The characteristics of overwash were analyzed by comparing

changes in dune heights and beach widths with beach erosion.

In this study, theduneheightwas measured on thefirst crest of

dunethat prevented overwash. The beach width was calculated

using the horizontal distance between the contact line of MSL

on the beach face and the location where the maximum dune

height was measured (Figure 9). The dune heights and beach

widths along the study area are shown in Figure 9, and thechanges between the two time periods are given in Figure 10.

The average dune height was 1.72 m in 1999; it had decreased

by 0.02 m to 1.70 m in 2002. The average beach width was

39.59 m in 1999; it was reduced by 6.91 m to 32.68 m in 2002.

The width decreased the most in the area with the higher

profile numbers, and no strong correlation was found between

the change in dune height and beach width. Dune heights

increased between lines 46 and 122 over the same period, but

they decreased at the lines close to the border of Louisiana.

Large decreases in dune height and beach width were clearly

illustrated between lines 150 and 156.

The landward and seaward movements of dunes and

shorelines are shown in Figure 11. The decrease in beach

width was caused by the movement of shoreline landward

along most of the survey area, but the locations of dunes and

shorelines moved seaward between lines 136 and 156 (Fig-

ure 11). It was evident that this area was eroded by different

conditions compared with other areas. Erosion by overwash

might have been dominant between lines 1 and 134, because

deposition was madeby the landwardmovement of eroded sand

from the dunes, and the shoreline also moved landward due to

overwash mostly from severe wave conditions. However,

because the impact of overwash was not strong due to high

dunes and wide beaches between lines 136 and 156, this

shoreline was eroded mainly by waves and longshore current,

and theseawardadvanceof the shoreline wascaused by erodedsediment from dunes. Park (2006) said that the intensity of

overwash and the ratio of landward sediment transport are

increased at steeper slopes, higher wave heights, and longer

wave periods.

There were four landfalls of storms in surrounding areas

such as south Texas and Louisiana from 1999 to 2002, but any

overwash caused by direct landfall of a storm did not occur in

the study area. However, beach erosion by overwash continued,

and we believe it was caused by remote storms.

Figure 9. Dune heights and widths along the study area between fall 1999 and spring 2002.

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CONCLUSIONS

The northeast Texas coast has been severely eroded for a

century, indicated by historical evidence that the highway and

roadway along the beachfront have been relocated landward

seven times. Morton (1997) analyzed long-period beach

changes in the study area over 20 years by aerial photography

and some ground-based surveys and estimated the rate of

retreat of coastline to be about 3.7 m/y. This was almost the

same rate of retreat measured in the study area between 1999

and 2005 before landfall of Hurricane Rita (2005). But the rate

sharply increased due to extreme overwash by landfall of that

storm. Erosion caused by Hurricane Rita was critical, and the

shoreline rapidly eroded by 12 to 15 m. Though the average

Figure 10. Changes in dune heights and beach widths between 1999 and 2002.

Figure 11. Movements of dune locations and mean sea level locations between 1999 and 2002.



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wave height and tide did not cause shoreline recession by

offshore transport or even alongshore transport, overwash was

suspected as a major cause of shoreline recession.

There were only two landfalling stormsTropical Storm

Ivan in 2004 and Hurricane Rita in 2005but more than 90%

of storms made landfall in distant areas such as south Texas,

Louisiana, Mississippi, and Alabama, which affected the study

area. It was observed that much erosion was caused by long-period waves of remote storms that made landfall in other

areas of the Gulf of Mexico. When Hurricane Katrina made

landfall in Louisiana 450 km away from the study area,

inundation and erosion by overwash provided evidence of the

impact of remote storms. Overwash by remote storms in the

Gulf of Mexico was a main cause of continued beach erosion in

the study area.

Over the years, the upper Texas coast has been eroded by

overwash; however, damage by overwash was not severe, and

much fine-grained sediment was deposited in the upper Texas

coast by various erosion deposition processes. Because the

frequency of occurrence of storms sharply increasedin theGulf

of Mexico after 2001, beach erosion along the Texas coast is

likely to become more severe due to climate change.

ACKNOWLEDGMENTS

Support for this work was provided by Jefferson County,

Texas, the U.S. Army Corps of Engineers District in

Galveston, Texas A&M University, and the Texas Sea Grant.

The authors sincerely appreciate the support and encourage-

ment of our colleagues.

LITERATURE CITED

Donnelly, C.; Wamsley, T.V.; Kraus, N.C.; Larson, M., and Hanson,

H., 2006. Morphologic classification of coastal overwash. In:

Proceedings of the 30th Conference of Coastal Engineering (SanDiego, California, ASCE), pp. 28052817.

Google Earth, 2009. Home Page. http://earth.google.com (accessedDecember 20, 2009).

Leatherman, S.P., 1983. Barrier dynamics and landward migrationwith Holocene sea-level rise. Nature, 301, 415417.

Morang, A., 2006. North Texas Sediment Budget, Sabine Pass to SanLuis Pass. ERDC/CHL TR-06-17. Vicksburg, Mississippi: U.S.

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