3

U.S. Department of the Interior

U.S. Geological Survey

Pamphlet to accompany

Scientific Investigations Map 3164

Land Area Change in Coastal Louisiana

from 1932 to 2010

By Brady R. Couvillion, John A. Barras, Gregory D. Steyer, William Sleavin, Michelle Fischer, 

Holly Beck, Nadine Trahan, Brad Griffin, and David Heckman

i

U.S. Department of the Interior

U.S. Geological Survey

Pamphlet to accompany

Scientific Investigations Map 3164

Land Area Change in Coastal Louisiana

from 1932 to 2010
U.S. Department of the Interior

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2011

This and other USGS information products are available at http://store.usgs.gov/

U.S. Geological Survey

Box 25286, Denver Federal Center

Denver, CO 80225

To learn about the USGS and its information products visit http://www.usgs.gov/

1-888-ASK-USGS

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

U.S. Government.

Although this report is in the public domain, permission must be secured from the individual copyright owners to 

reproduce any copyrighted materials contained within this report.

Suggested citation:

Couvillion, B.R.; Barras, J.A.; Steyer, G.D.; Sleavin, William; Fischer, Michelle; Beck, Holly; Trahan, Nadine; Griffin, 

Brad; and Heckman, David, 2011, Land area change in coastal Louisiana from 1932 to 2010: U.S. Geological Survey 

Scientific Investigations Map 3164, scale 1:265,000, 12 p. pamphlet.
Contents

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

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

Methodology ..................................................................................................................................................1

Land Area Changes ......................................................................................................................................4

Land Change Trends .....................................................................................................................................5

Discussion and Conclusions .......................................................................................................................5

References ...................................................................................................................................................12

Figures

1. Map of the study area in coastal Louisiana ............................................................................3

2. Land area in coastal Louisiana, 1932 to 2010 ...........................................................................4

3. Persistent land loss and land gain in coastal Louisiana by period 

and by basin for 1932–2010..........................................................................................................8

4. Persistent land loss and land gain coastwide across Louisiana by 

period for 1932–2010 ....................................................................................................................9

5. Linear regressions of land area change trends coastwide across 

Louisiana, 1985–2010 .................................................................................................................10

6. Linear regressions of land area change trends in coastal Louisiana 

by hydrologic basin, 1985–2010 ...................................................................................................11

Tables

1. Land area in coastal Louisiana by basin, 1932–2010 ..............................................................2

2. Water levels at selected gages on the date of acquisition for imagery 

used in the land area estimates ................................................................................................5

 3. Persistent land loss and land gain in coastal Louisiana by basin, 1932–2010 ...................6
New Orleans

Mississippi

Louisiana

Texas Louisiana

Cameron

Lake Pontchartrain

Big

 Mar

Lake Maurepas

Lake Salvador

Barataria Bay

Timbalier Bay

Terrebonne Bay

Caillou Lake

Lake

 Mechant

Lake

 Boudreaux

Little Lake

Atchafalaya Bay

Gulf of Mexico

Lake Cataouatche

Atcha af al

ay

vi R

r e

Lake Borgne

East Cote 

Blanche Bay

West Cote 

Blanche Bay

Vermilion Bay

White Lake

Grand Lake

Calcasieu

Lake

Black

 Lake

Freshwater Bayou

Wax Lake Outlet

Marsh

Island

 Lake PontchartrainCauseway

Gulf Intracoastal Waterway

Gulf Intracoastal Waterway

Gulf Intracoastal Waterway

Mississippi River-Gulf Outlet Canal M si s si s pi pi River

Mississippi River

Mississippi River

Southwest Pass South Pass

Pass a Loutre

East Bay

West Bay

Garden

Island 

Bay

Bayou Lafourche

Labranche wetlands

Calcasieu Ship Channel

Sweet

 Lake

Breton Sound

Lake

Felicity

Gulf of Mexico

Gulf of Mexico

Calcasieu-Sabine Basin

Chandeleur Sound

C

h

a

n

d

e

l

e

u

r

I

s

l

a

n

d

s

Teche-Vermilion 

Basin

Atchafalaya 

Delta Basin

Terrebonne Basin

Barataria Basin

Mississippi River 

Delta Basin

Breton Sound

Basin

Pontchartrain

Basin

Lac des 

Allemands

Uplands (>10m)

Uplands (>10m)

Uplands (>10m)

Uplands (>10m)

Gulf of Mexico

Hackberry

Johnsons Bayou Grand Chenier

Wax Lake Delta

Atchafalaya Delta

Morgan

City

IntracoastalCity

PecanIsland

Houma

Thibodaux

Golden

Meadow

Port Fourchon

Larose

Montegut

Dulac

Theriot

Amelia

Cut Off

Lake Charles

Sulphur

Vinton

Iowa Welsh

Jennings

Crowley

Rayne

Lafayette

New Iberia

Jeanerette

Abbeville

Franklin

Donaldsonville

White Castle

Plaquemine

Port Allen Baton Rouge

Slidell

Mandeville

Covington

Ponchatoula

Gonzales

Lake 

Verret

Lake 

Palourde

Flat

Lake 

Lake 

Fausse Pointe

The 

Pen

Breaux Bridge

Redfish 

Bay

Blind

Bay

Quarantine

Bay

Adams

Bay

Bastian

Bay

Lost Lake Four League Bay

Bayou Perot

Bayou Rigolettes

Grand

Lake

Lake De Cade

Lake

Saint Catherine

Sabine

Lake

Mermentau Basin

Lake Lery

Scale 1:265,000

10 0 10 20 30 40 5

Kilometers

10 0 10 20 30 40 5

Miles

Uplands5

Persistent forested wetland5

Persistent wetlandPersistent water

5

Basin boundary 

1Gain is determined by the last date a particular pixel transitioned from water to land and remained land throughout the period of observation.

2Loss is determined by the last date a particular pixel transitioned from land to water and remained water throughout the period of observation.

EXPLANATION

1977–85 land gain1,41932–56 land gain11956–73 land gain1,41973–75 land gain1,41975–77 land gain1,4

1990–95 land gain1

1985–88 land gain11988–90 land gain1

2004–6 land gain11995–98 land gain11998–99 land gain11999–2002 land gain1

1977–85 land loss2,41932–56 land loss21956–73 land loss2,41973–75 land loss2,41975–77 land loss2,4

1990–95 land loss2

1985–88 land loss21988–90 land loss2

2004–6 land loss21995–98 land loss21998–99 land loss21999–2002 land loss2

2006–8 land gain12008–9 land gain1,3

2006–8 land loss22008–9 land loss2,3

Developed5

3Because this date range has only one ending dataset, some of these effects may be temporary phenomena.

4This date range contains at least one date in which the land/water data were created from Landsat Multispectral Scanner System (MSS). 

2002–4 land gain1 2002–4 land loss2

5Land cover categories based on 2008 data. “Persistent” is defined as not having undergone a consistent change in land/water category during 

 the observation period.

2009–10 new land1,3 2009–10 new water2,3

Uplands5

Persistent forested wetland5

Persistent wetlandPersistent water

5

Developed5

Background imagery(outside modified Coastal Zone Boundary)

Background imagery (inside modified Coastal Zone Boundary)

Persistent water

Basin boundary 

1Gain is determined by the last date a particular pixel transitioned from water to land and remained land throughout the period of observation.

2Loss is determined by the last date a particular pixel transitioned from land to water and remained water throughout the period of observation.

1990–95 land gain1

1988–90 land gain1

2004–6 land gain11995–98 land gain11998–99 land gain11999–2002 land gain1

1990–95 land loss2

1988–90 land loss2

2004–6 land loss21995–98 land loss21998–99 land loss21999–2002 land loss2

2006–8 land gain12008–9 land gain1,3

2006–8 land loss22008–9 land loss2,3

3Because this date range has only one ending dataset, some of these effects may be temporary phenomena.

4This date range contains at least one date in which the land/water data were created from Landsat Multispectral Scanner System (MSS). 

2002–4 land gain1 2002–4 land loss2

5Land cover categories based on 2008 data. “Persistent” is defined as not having undergone a consistent change in land/water category during 

 the observation period.

2009–10 new land1,3 2009–10 new water2,3

Uplands5

Persistent forested wetland5

Persistent wetlandPersistent water

5

Developed5

Background imagery(outside modified Coastal Zone Boundary)

Uplands5

Persistent forested wetland5

Persistent wetlandPersistent water

5

Basin boundary 

1Gain is determined by the last date a particular pixel transitioned from water to land and remained land throughout the period of observation.

2Loss is determined by the last date a particular pixel transitioned from land to water and remained water throughout the period of observation.

EXPLANATION

1977–85 land gain1,41932–56 land gain11956–73 land gain1,41973–75 land gain1,41975–77 land gain1,4

1990–95 land gain1

1985–88 land gain11988–90 land gain1

2004–6 land gain11995–98 land gain11998–99 land gain11999–2002 land gain1

1977–85 land loss2,41932–56 land loss21956–73 land loss2,41973–75 land loss2,41975–77 land loss2,4

1990–95 land loss2

1985–88 land loss21988–90 land loss2

2004–6 land loss21995–98 land loss21998–99 land loss21999–2002 land loss2

2006–8 land gain12008–9 land gain1,3

2006–8 land loss22008–9 land loss2,3

Developed5

3Because this date range has only one ending dataset, some of these effects may be temporary phenomena.

4This date range contains at least one date in which the land/water data were created from Landsat Multispectral Scanner System (MSS). 

2002–4 land gain1 2002–4 land loss2

5Land cover categories based on 2008 data. “Persistent” is defined as not having undergone a consistent change in land/water category during 

 the observation period.

2009–10 new land1,3 2009–10 new water2,3

Uplands5

Persistent forested wetland5

Persistent wetlandPersistent water

5

Developed5

Background imagery(outside modified Coastal Zone Boundary)

Background imagery (inside modified Coastal Zone Boundary)

Persistent water

Basin boundary 

1Gain is determined by the last date a particular pixel transitioned from water to land and remained land throughout the period of observation.

2Loss is determined by the last date a particular pixel transitioned from land to water and remained water throughout the period of observation.

1990–95 land gain1

1988–90 land gain1

2004–6 land gain11995–98 land gain11998–99 land gain11999–2002 land gain1

1990–95 land loss2

1988–90 land loss2

2004–6 land loss21995–98 land loss21998–99 land loss21999–2002 land loss2

2006–8 land gain12008–9 land gain1,3

2006–8 land loss22008–9 land loss2,3

3Because this date range has only one ending dataset, some of these effects may be temporary phenomena.

4This date range contains at least one date in which the land/water data were created from Landsat Multispectral Scanner System (MSS). 

2002–4 land gain1 2002–4 land loss2

5Land cover categories based on 2008 data. “Persistent” is defined as not having undergone a consistent change in land/water category during 

 the observation period.

2009–10 new land1,3 2009–10 new water2,3

Uplands5

Persistent forested wetland5

Persistent wetlandPersistent water

5

Developed5

Background imagery(outside modified Coastal Zone Boundary)

Uplands5

Persistent forested wetland5

Persistent wetlandPersistent water

5

Basin boundary 

1Gain is determined by the last date a particular pixel transitioned from water to land and remained land throughout the period of observation.

2Loss is determined by the last date a particular pixel transitioned from land to water and remained water throughout the period of observation.

EXPLANATION

1977–85 land gain1,41932–56 land gain11956–73 land gain1,41973–75 land gain1,41975–77 land gain1,4

1990–95 land gain1

1985–88 land gain11988–90 land gain1

2004–6 land gain11995–98 land gain11998–99 land gain11999–2002 land gain1

1977–85 land loss2,41932–56 land loss21956–73 land loss2,41973–75 land loss2,41975–77 land loss2,4

1990–95 land loss2

1985–88 land loss21988–90 land loss2

2004–6 land loss21995–98 land loss21998–99 land loss21999–2002 land loss2

2006–8 land gain12008–9 land gain1,3

2006–8 land loss22008–9 land loss2,3

Developed5

3Because this date range has only one ending dataset, some of these effects may be temporary phenomena.

4This date range contains at least one date in which the land/water data were created from Landsat Multispectral Scanner System (MSS). 

2002–4 land gain1 2002–4 land loss2

5Land cover categories based on 2008 data. “Persistent” is defined as not having undergone a consistent change in land/water category during 

 the observation period.

2009–10 new land1,3 2009–10 new water2,3

Uplands5

Persistent forested wetland5

Persistent wetlandPersistent water

5

Developed5

Background imagery(outside modified Coastal Zone Boundary)

Background imagery (inside modified Coastal Zone Boundary)

Persistent forested wetland5

Persistent wetlandPersistent water

5

Basin boundary 

1Gain is determined by the last date a particular pixel transitioned from water to land and remained land throughout the period of observation.

2Loss is determined by the last date a particular pixel transitioned from land to water and remained water throughout the period of observation.

1977–85 land gain1,4

1990–95 land gain1

1985–88 land gain11988–90 land gain1

2004–6 land gain11995–98 land gain11998–99 land gain11999–2002 land gain1

1977–85 land loss2,4

1990–95 land loss2

1985–88 land loss21988–90 land loss2

2004–6 land loss21995–98 land loss21998–99 land loss21999–2002 land loss2

2006–8 land gain12008–9 land gain1,3

2006–8 land loss22008–9 land loss2,3

3Because this date range has only one ending dataset, some of these effects may be temporary phenomena.

4This date range contains at least one date in which the land/water data were created from Landsat Multispectral Scanner System (MSS). 

2002–4 land gain1 2002–4 land loss2

5Land cover categories based on 2008 data. “Persistent” is defined as not having undergone a consistent change in land/water category during 

 the observation period.

2009–10 new land1,3 2009–10 new water2,3

Uplands5

Persistent forested wetland5

Persistent wetlandPersistent water

5

Developed5

Background imagery(outside modified Coastal Zone Boundary)

Persistent wetlandPersistent water

5

Basin boundary 

1Gain is determined by the last date a particular pixel transitioned from water to land and remained land throughout the period of observation.

2Loss is determined by the last date a particular pixel transitioned from land to water and remained water throughout the period of observation.

1977

85 land gain

1990–95 land gain1

1985–88 land gain11988–90 land gain1

2004–6 land gain11995–98 land gain11998–99 land gain11999–2002 land gain1

1977

85 land loss

1990–95 land loss2

1985–88 land loss21988–90 land loss2

2004–6 land loss21995–98 land loss21998–99 land loss21999–2002 land loss2

2006–8 land gain12008–9 land gain1,3

2006–8 land loss22008–9 land loss2,3

3Because this date range has only one ending dataset, some of these effects may be temporary phenomena.

4This date range contains at least one date in which the land/water data were created from Landsat Multispectral Scanner System (MSS). 

2002–4 land gain1 2002–4 land loss2

5Land cover categories based on 2008 data. “Persistent” is defined as not having undergone a consistent change in land/water category during 

 the observation period.

2009–10 new land1,3 2009–10 new water2,3

Uplands5

Persistent forested wetland5

Persistent wetlandPersistent water

5

Developed5

Background imagery(outside modified Coastal Zone Boundary)
By Brady R. Couvillion, John A. Barras, Gregory D. Steyer, William Sleavin, 

Michelle Fischer, Holly Beck, Nadine Trahan, Brad Griffin, and David Heckman

Abstract

Coastal Louisiana wetlands make up the seventh largest 

delta on Earth, contain about 37 percent of the estuarine 

herbaceous marshes in the conterminous United States, 

and support the largest commercial fishery in the lower 

48 States. These wetlands are in peril because Louisiana 

currently undergoes about 90 percent of the total coastal 

wetland loss in the continental United States. Documenting 

and understanding the occurrence and rates of wetland 

loss are necessary for effective planning, protection, and 

restoration activities.

The analyses of landscape change presented in this report 

use historical surveys, aerial data, and satellite data to track 

landscape changes. Summary data are presented for 1932–

2010; trend data are presented for 1985–2010. These later 

data were calculated separately because of concerns over the 

comparability of the 1932 and 1956 datasets (which are based 

on survey and aerial data, respectively) with the later datasets 

(which are all based on satellite imagery).

These analyses show that coastal Louisiana has 

undergone a net change in land area of about -1,883 square 

miles (mi2) from 1932 to 2010. This net change in land area 

amounts to a decrease of about 25 percent of the 1932 land 

area. Persistent losses account for 95 percent of this land area 

decrease; the remainder are areas that have converted to water 

but have not yet exhibited the persistence necessary to be 

classified as “loss.” Trend analyses from 1985 to 2010 show 

a wetland loss rate of 16.57 mi2 per year. If this loss were to 

occur at a constant rate, it would equate to Louisiana losing an 

area the size of one football field per hour.

The use of 17 datasets plus the application of consistent 

change criteria in this study provide opportunities to better 

understand the timing and causal mechanisms of wetland loss 

that are critical for forecasting landscape changes in the future.

Introduction

The U.S. Geological Survey (USGS) analyzed landscape 

changes in coastal Louisiana by determining land and water 

classifications for 17 datasets. These datasets include 

survey data from 1932, aerial data from 1956, and Landsat 

Multispectral Scanner System (MSS) and Thematic Mapper 

(TM) data from the 1970s to 2010. Previous studies have 

analyzed land change in coastal Louisiana, but many are 

out of date, provide data for limited time periods, or lack 

the temporal frequency necessary to provide information 

about when the loss occurred. The purpose of this study is 

to provide updated estimates of persistent land change and 

historical land change trends for coastal Louisiana and for 

each hydrologic basin, as defined by the Coastal Wetlands 

Planning, Protection and Restoration Act Program (n.d.), 

for the 1932–2010 period of record. The use of 17 datasets 

plus the application of consistent change criteria in this 

study provide opportunities to better understand the timing 

and causal mechanisms of wetland loss that are critical for 

forecasting landscape changes in the future.

Methodology

This study analyzed changes in the extent of land in 

coastal Louisiana by using 17 datasets summarizing land 

and water areas from 1932 to 2010 (table 1). The datasets 

were derived from multiple sources including (1) historical 

survey data (1932); (2) National Wetlands Inventory (NWI) 

data based on aerial photography (1956); (3) Landsat MultiSpectral Scanner (MSS) data (1973–79); and (4) Landsat 

Thematic Mapper (TM) satellite imagery classified into land 

and water categories (1985–2010). Variable data coverage 

among the 1932 and 1956 datasets and all subsequent data 

required an assumption of no change in the area of no data 

coverage (areas with no overlap) in those datasets. No change 

is assumed in land area from 1932 to 1956 and from 1956 

to 1973 in portions of the dataset that occur outside the 

boundaries of the 1932 and 1956 data coverage. (Refer to 

figure 1 for more information regarding the areas within the 

coastal basins to which this assumption was applied.)

The areas missing from the 1932 and 1956 datasets 

mostly consist of forested wetlands. These areas are 

historically stable, so the assumption of “no change” is correct 

in most instances; however, the area and change summaries 

should only be used with an in-depth understanding of the 

impacts of this assumption in areas where there are no data in 

1932 and 1956.

Land Area Change in Coastal Louisiana from 1932 to 2010
2 Land Area Change in Coastal Louisiana from 1932 to 2010 Table 1. Land area in coastal Louisiana by basin, as defined by the Coastal Wetlands Planning, Protection and Restoration Act Program (n.d.) , 1932–2010. [Land area in square miles. Dates are approximate averages of imagery used for various portions of the coast. Area estimates are known to be highly influenced by water levels on the date of acquisition of the imagery. Refer to table 2 for water level information] Decimal date1 Basin Atchafalaya Delta Barataria Breton Sound Calcasieu- Sabine Mermentau Mississippi River Delta Pontchartrain Teche- Vermilion Terrebonne Coastwide 19322 212.58 1,479.78 427.63 824.99 958.27 262.07 1,105.19 548.94 1,726.48 7,545.92 19562 197.57 1,382.60 376.07 810.52 918.78 241.82 1,038.25 520.24 1,618.43 7,104.28 1973.9 197.04 1,339.06 395.08 691.40 888.94 80.34 1,029.61 529.78 1,598.43 6,749.68 1975.7 210.52 1,224.77 347.76 697.76 902.95 94.27 999.08 528.12 1,529.68 6,534.90 1977.4 190.51 1,297.88 356.49 591.98 799.89 138.71 993.72 500.33 1,396.13 6,265.65 1985.1 186.80 1,149.74 333.87 615.44 780.54 121.63 979.22 492.36 1,325.53 5,985.12 1988.1 205.89 1,170.51 339.86 636.36 785.76 129.06 991.19 487.43 1,393.58 6,139.65 1990.8 198.92 1,104.10 313.00 659.23 835.71 137.99 970.87 477.91 1,322.58 6,020.31

1995.7 225.18 1,026.72 292.17 637.31 849.77 136.91 934.51 476.86 1,263.14 5,842.571998.2 180.94 1,092.40 313.33 596.14 738.04 114.04 961.99 484.70 1,266.84 5,748.431999.9 231.23 1,055.72 300.26 644.40 834.03 152.01 946.91 489.33 1,270.68 5,924.582002.2 211.68 1,082.12 304.58 629.88 781.19 133.59 944.58 485.88 1,294.11 5,867.612004.9 218.90 1,048.56 295.87 654.05 816.48 119.02 936.71 474.31 1,253.01 5,816.892006.8 213.99 1,035.94 264.10 625.14 731.29 105.98 912.33 477.43 1,241.69 5,607.892008.8 203.15 1,016.36 240.40 580.23 727.70 113.74 900.98 464.57 1,204.62 5,451.752009.8 219.35 1,010.85 242.50 568.86 731.03 108.69 903.23 470.82 1,204.45 5,459.782010.8 229.31 1,024.19 253.40 611.42 803.09 138.03 910.96 471.57 1,220.73 5,662.71

1Decimal dating is a more specific dating system than the calendar year and is used to facilitate statistical analyses. It is derived by dividing the day of the year (in the Julian system) by the number of 

 days in the year.

2Calendar dates were not available.
Methodology 

3

Path 24

Path 23

Path 22

Path 21

Missing from 1932 data: 1,115 mi2 within modified Coastal Zone Boundary

Missing from 1956 data: 920 mi2within modified Coastal Zone Boundary

Missing from 1932 and 1956 data: 577 mi2within modified Coastal Zone Boundary

EXPLANATION

Modified Coastal Zone Boundary: 14,587 mi2

Domain shown: 22,895 mi2

Landsat Worldwide Reference System-2 (WRS-2)

Excluded from domain (shown for reference purposes only)

Uplands (>10m) 

Uplands (>10m) 

Figure 1. Map of the study area in coastal Louisiana. The coastal zone boundary was modified to improve the conservation plan boundary. The conservation plan boundary delineates the zone for which statistics were calculated and isolates coastal regions while excluding fastlands (defined as developed, agricultural, and other protected areas) from statistical analysis of coastal land change. Of particular note are the areas of non-overlapping data coverage in the 1932 and 1956 datasets (based on survey and aerial data) and in the 1973–2010 datasets (based on satellite imagery data). Because no data exist for these non-overlapping areas, an assumption of no change in those areas has been used for those time periods in the analyses (a reasonable assumption since a majority of these data voids occurs in areas dominated by forested wetlands, a habitat type known to have been particularly stable in past observations). The background image is shown for reference purposes to a northern boundary delineated by the 10-m elevation contour (referenced to the North American Vertical Datum of 1988 [NAVD 88]).
4 Land Area Change in Coastal Louisiana from 1932 to 2010

Preprocessing of all datasets included use of ERDAS 

IMAGINE AutoSync (ERDAS Inc., Norcross, Ga.), a software 

that uses an automated process to align common landform 

features between images. To assess change, the geometric 

registration between datasets must be highly accurate. 

Misalignment of features at the same location could produce 

invalid land change results. This processing step was critical 

in ensuring that the 1932 and 1956 data aligned with the later 

satellite-based data. The Landsat MSS data (1973, 1977, and 

1979), which have a native 60-meter (m) resolution, were first 

resampled to a 30-m resolution by using a cubic convolution 

resampling method to facilitate comparability with later 

Landsat TM-based data (native 30-m resolution). Conducting 

this resampling prior to land-water classification is more 

appropriate than resampling the results of the land-water 

classification. All satellite imagery data were then classified 

into land/water categories by using a standard methodology 

similar to that used in previous studies (Barras, 2006, 2007; 

Barras and others, 2008).

The methodology used in this study relied heavily on 

the use of the near infrared band of Landsat data (MSS: Band 

7; TM: Band 5) in the early stages of classification. Near 

infrared (NIR) was selected because the wavelengths in this 

range, 1.55–1.75 micrometers, 

are particularly informative and 

discriminatory with regard to land 

and water categories. Supervised 

and unsupervised classification 

was then used to account for 

areas that may be incorrectly 

classified by the NIR band alone. 

Areas that need further attention 

for accurate classification 

commonly include highly 

turbid water areas and floating 

aquatic vegetation. These areas 

were manually recoded to their 

appropriate land/water categories 

by expert analyses.

Land Area Changes 

The resulting land area 

data were summarized by time 

period and by basin (table 1 

and fig. 2). These analyses 

show that coastal Louisiana 

has experienced a net change 

in land area of approximately 

-1,883 mi2 from 1932 to 

2010. Land area estimates can 

vary substantially because of 

environmental variations such 

as seasonality and, most notably, water-level variations 

on the date of acquisition (DOA) of the data (Morton and 

others, 2005; Bernier and others, 2006). (Refer to table 

2 for more information regarding the water levels on the 

DOA for the data used in these analyses.) To reduce some 

of the errors associated with apparent land change caused 

by misclassification or transient environmental phenomena, 

two approaches were utilized. Changes must persist for at 

least two time periods (of variable length, depending upon 

availability of cloud-free imagery) following the initial 

change, and anomalous changes among land and water 

categories can only occur in less than 20 percent of the 

remaining datasets. The mapped dataset identifies only these 

areas of persistent and consistent change (table 3; figs. 3 and 

4). For this reason, recent land changes (2008–9 and 2009–10) 

cannot yet be defined as persistent because data are not 

available to confirm that these changes have persisted into the 

two following analysis periods. These unconfirmed changes 

are instead referred to as “new land investigation areas” and 

“new water investigation areas” (figs. 3 and 4). 

It is important to note that there is a difference between 

net land area change (table 1 and fig. 1) and persistent losses 

and gains (table 3, figs. 3, 4). As classification of an area as 

2 1956 assumes no change from 1956 to 1973 in 920 mi2

 of coastal Louisiana.

1 1932 assumes no change from 1932 to 1956 in 1,115 mi2

 and no change from 1932 to 1973 in 577 mi2

of coastal Louisiana.

3 Datasets are based on Landsat Multispectral Scanner System (MSS) data, which are originally at 60-m resolution.

7,722

7,529

7,143

7,336

6,950

6,757

6,564

6,371

6,178

5,985

5,792

5,598

5,405

Coastal Louisiana land area, in square miles

1930 1940 1950 1960 1970 1980 1990 2000 2010

Year

1

2

3

3

3

Figure 2. Land area in coastal Louisiana, 1932–2010. Coastwide, net land 

area decrease from 1932 to 2010 was 1,883 mi2. (See table 1 for specific area 

measurements.)
Discussion and Conclusions 5

loss or gain depends upon persistence criteria, the amount 

of area of persistent loss or gain for a particular period can 

be less than or greater than the net land area change for that 

period. This occurs because persistent losses in a particular 

location can be offset by transitory gains in another.

Land Change Trends

Land change trends by hydrologic basin within the 

modified coastal zone were calculated solely on the basis 

of Landsat TM data for 1985–2010 (figs. 5 and 6). Linear 

regressions were calculated for two time periods, 1985–2004 

and 1985–2010, because strong hurricanes in 2005 (Katrina 

and Rita) and 2008 (Gustav and Ike) greatly impacted both 

eastern and western coastal Louisiana wetlands. Results show 

that the Atchafalaya Delta Basin is the only area in coastal 

Louisiana showing increasing land area (positive land change 

slope), but the rate of growth in this one basin is not sufficient 

to offset the losses coastwide, particularly in years of 

increased hurricane activity. The 2005 and 2008 datasets were 

excluded to reduce the influence of transitory storm effects. 

The variability in land area data points around the slope 

illustrates the influence of various sources of environmental 

variance or classification error.

Discussion and Conclusions

This assessment provides a comprehensive analysis 

of historical trends and rates of land area change in coastal 

Louisiana. The primary improvement over past efforts is an 

increased temporal frequency of analysis. This gives scientists 

the ability to better quantify the amount of wetland loss and 

the time period in which it was lost. Having this information 

can allow gradual loss patterns to be distinguished from 

losses due to episodic events such as hurricanes. The spatial 

and temporal patterns observed reveal a dynamic landscape 

changing as a result of the complex and often interactive 

effects of natural and human-induced processes.

Table 2. Water levels at a selected gage (station ID: 8761724, located near Grand Isle, La.) on the date of acquisition for imagery 

used in the land area estimates.

Path 211 Path 221 Path 231 Path 241

Decimal

 date2

Calendar

date

Gage height, 

in feet3

Calendar

date

Gage height, 

in feet3

Calendar

date

Gage height, 

in feet3

Calendar

date

Gage height, 

in feet3

19324 Not available Not available Not available Not available

19564 Not available Not available Not available Not available

1973.9 12/5/1973 Not available 2/3/1973 Not available 12/7/1973 Not available 12/9/1973 Not available

1975.7 10/11/1975 Not available 4/15/1975 Not available 9/25/1975 Not available 9/26/1975 Not available

1977.4 7/2/1977 Not available 6/3/1977 Not available 1/23/1977 Not available 4/6/1977 Not available

1985.1 10/11/1985 6.79 1/19/1985 5.81 1/26/1985 5.94 12/3/1985 6.30

1988.1 12/4/1987 6.46 1/28/1988 5.02 12/2/1987 6.33 1/26/1988 5.97

1990.8 2/14/1991 5.97 11/1/1990 6.56 11/24/1990 6.40 10/30/1990 6.69

1995.7 10/7/1995 6.89 9/28/1995 6.86 10/5/1995 6.92 9/10/1995 6.82

1998.2 2/17/1998 6.04 2/24/1998 5.64 3/3/1998 6.14 3/10/1998 6.17

1999.9 11/27/1999 6.36 11/18/1999 6.46 11/16/1999 6.50 10/24/1999 6.73

2002.2 1/3/2002 6.00 2/27/2002 5.45 2/2/2002 5.97 1/8/2002 6.00

2004.9 10/15/2004 6.76 11/7/2004 6.46 10/13/2004 6.79 11/5/2004 6.59

2005.8 10/18/2005 6.73 10/25/2005 6.10 10/16/2005 6.66 10/23/2005 6.69

2006.8 1/25/2007 5.97 10/28/2006 6.53 11/4/2006 6.66 12/13/2006 6.23

2008.8 10/26/2008 6.82 10/1/2008 6.89 10/8/2008 6.89 9/29/2008 6.89

2009.8 11/14/2009 6.66 11/5/2009 6.69 11/12/2009 6.66 11/3/2009 6.73

2010.8 10/16/2010 6.53 10/7/2010 6.30 10/14/2010 6.36 10/5/2010 6.86

1

Refer to figure 1. These “path” designations correspond to the Landsat Worldwide Reference System-2 (WRS-2) tiling system.

2

Decimal dating is a more specific dating system than the calendar year and is used to facilitate statistical analyses. It is derived by dividing the day of

 the year (in the Julian system) by the number of days in the year.

3

Elevations provided in station datum.

4

Calendar dates were not available.
6 Land Area Change in Coastal Louisiana from 1932 to 2010

Table 3. Persistent land loss and land gain in coastal Louisiana by basin, as defined by the Coastal Wetlands Planning, Protection 

and Restoration Act Program (n.d.) ,1932–2010.

[Land area in square miles]

Basin 1932–56 1956–73 1973–75 1975–77 1977–85 1985–88 1988–90 1990–95 

Loss 

Atchafalaya Delta -4.48 -1.92 -1.75 -0.90 -0.64 -0.99 -1.37 -1.15 

Barataria -56.46 -70.98 -64.21 -27.94 -42.81 -16.80 -26.30 -26.76 

Breton Sound -30.94 -11.34 -9.95 -9.58 -7.97 -5.67 -8.28 -9.64 

Calcasieu-Sabine -8.41 -66.70 -17.30 -15.08 -9.59 -6.19 -4.22 -6.90 

Mermentau -18.68 -24.35 -7.00 -9.31 -10.01 -6.59 -5.49 -6.58 

Mississippi River Delta -34.06 -61.93 -10.51 -9.61 -4.86 -2.44 -5.64 -4.41 

Pontchartrain -34.41 -32.50 -12.74 -12.84 -9.47 -6.88 -9.67 -11.07 

TecheVermilion -14.68 -8.40 -4.43 -4.22 -3.06 -3.23 -3.23 -2.81 

Terrebonne -75.28 -46.25 -45.65 -50.87 -35.11 -22.97 -27.54 -30.63 

Total -277.41 -324.39 -173.55 -140.35 -123.52 -71.78 -92.18 -99.94 

Basin 1932–56 1956–73 1973–75 1975–77 1977–85 1985–88 1988–90 1990–95 

Gain 

Atchafalaya Delta 0.89 1.12 0.63 0.32 1.77 1.17 0.60 2.47 

Barataria 1.11 0.10 0.05 0.45 0.24 0.05 0.08 0.15 

Breton Sound 1.34 0.32 0.01 0.12 0.20 0.06 0.16 0.14 

Calcasieu-Sabine 1.87 1.68 0.18 0.26 0.74 0.19 0.19 0.57 

Mermentau 1.71 0.57 0.12 0.10 0.28 0.13 0.53 1.16 

Mississippi River Delta 2.43 0.50 0.95 2.34 2.52 1.10 1.06 0.67 

Pontchartrain 1.59 1.69 0.61 0.17 0.30 0.16 0.28 0.20 

TecheVermilion 1.64 0.34 0.01 0.04 0.13 0.05 0.05 0.16 

Terrebonne 2.96 0.21 0.25 0.31 0.49 0.26 0.24 0.28 

Total 15.53 6.52 2.82 4.10 6.68 3.17 3.21 5.79 

1

Data are rounded to two decimal places; values shown may not add to totals shown.
Discussion and Conclusions 7

1995–98 1998–99 1999–2002 2002–4 2004–6 2006–8 2008–9 2009–10

Total 

persistent

Loss Negative change

-0.83 -0.49 -0.39 -0.51 -0.37 -0.66 -0.01 -0.02 -16.49

-16.76 -17.83 -9.12 -8.95 -13.76 -15.86 -3.94 -3.23 -421.71

-6.93 -6.47 -4.26 -5.48 -29.32 -12.25 -0.98 -1.79 -160.87

-7.15 -5.19 -2.85 -1.59 -22.00 -23.74 -1.30 -0.72 -198.94

-5.74 -3.96 -4.03 -2.76 -22.26 -6.13 -0.43 -0.60 -134.37

-1.89 -1.02 -1.02 -3.46 -10.11 -0.90 -0.14 -0.03 -152.02

-7.85 -6.68 -4.20 -5.70 -15.14 -7.24 -1.26 -1.60 -179.25

-3.57 -3.15 -1.71 -3.23 -3.78 -4.51 -0.29 -0.29 -64.61

-23.12 -22.50 -11.99 -9.63 -18.27 -23.40 -12.31 -4.49 -459.99

-73.83 -67.29 -39.57 -41.30 -135.02 -94.69 -20.65 -12.77 -1,788.241

1995–98 1998–99 1999–2002 2002–4 2004–6 2006–8 2008–9 2009–10

Total 

persistent

Gain Positive change

0.76 4.74 0.98 1.12 2.28 2.08 3.77 5.25 29.95

0.29 0.09 0.30 0.31 1.25 0.58 0.35 0.52 5.91

0.38 0.20 0.31 0.27 1.15 0.59 0.29 0.49 6.03

0.20 0.28 0.40 0.86 0.81 0.51 0.08 0.19 9.02

0.70 0.18 0.33 0.28 0.44 0.19 0.04 0.11 6.87

0.83 1.62 1.43 0.63 2.62 2.52 0.37 2.16 23.74

0.16 0.07 0.32 0.30 1.11 0.64 0.27 0.46 8.31

0.09 0.10 0.12 0.14 0.51 0.24 0.13 0.11 3.85

0.40 0.76 0.47 0.37 1.67 0.67 0.66 0.43 10.42

3.80 8.03 4.66 4.27 11.82 8.03 5.95 9.71 104.111
8 Land Area Change in Coastal Louisiana from 1932 to 2010

*

As persistence of these changes cannot yet be determined, these areas are coined “new water 

 investigation areas” and “new land investigation areas.” These are areas under investigation for 

 persistence of the changes observed.

-325

-300

-275

-250

-225

-200

-175

-150

-125

-100

-75

-50

-25

0

25 *

*

 Persistent area change, in square miles

Figure 3. Persistent land loss and land gain across coastal Louisiana by period for 1932–2010.

EXPLANATION

1

Gain is determined by the last date a particular pixel transitioned from water to land and remained land throughout the period of observation. 2

Loss is determined by the last date a particular pixel transitioned from land to water and remained water throughout the period of observation. 3

Because this date range has only one ending dataset, some of these effects may be temporary phenomena.

4

This date range contains at least one date in which the land/water data were created from Landsat Multispectral Scanner System (MSS). 

1977–85 land gain1,4

1932–56 land gain1

1956–73 land gain1,4

1973–75 land gain1,4

1975–77 land gain1,4

1990–95 land gain1

1985–88 land gain1

1988–90 land gain1

2004–6 land gain1

1995–98 land gain1

1998–99 land gain1

1999–2002 land gain1

1977–85 land loss2,4

1932–56 land loss2

1956–73 land loss2,4

1973–75 land loss2,4

1975–77 land loss2,4

1990–95 land loss2

1985–88 land loss2

1988–90 land loss2

2004–6 land loss2

1995–98 land loss2

1998–99 land loss2

1999–2002 land loss2

2006–8 land gain1

2008–9 land gain1,3

2006–8 land loss2

2008–9 land loss2,3

2002–4 land gain1 2002–4 land loss2

2009–10 new land1,3 2009–10 new water2,3
Discussion and Conclusions 9

*

*

*

*

*

*

*

*

*

-5-4-3-2-

6543210

1

-80-70-60-50-40-30-20-1

0

0

10

-35-30-25-20-15-10

-

50

5

-70-60-50-40-30-20-1

0

0

10

-25-20-15-10

-

50

5

-65-55-45-35-25-15

-

5

5

-35-30-25-20-15-1

50

-5

0

-16-14-12-1

20

-2-4-6-8

0

-80-70-60-50-40-30-20-1

0

0

10

*

As persistence of these changes cannot yet be determined, these areas are coined “new water investigation areas” and “new land investigation areas.” 

 These are areas under investigation for persistence of the changes observed.

Atchafalaya Delta Basin Barataria Basin Breton Sound Basin 

Calcasieu-Sabine Basin Mermentau Basin Mississippi River Delta Basin 

Pontchartrain Basin Teche-Vermilion Basin 

Terrebonne Basin 

, in square miles aer a dnaL

, in square miles aer a dnaL

, in square miles aer a dnaL

, in square miles aer a dnaL

, in square miles aer a dnaL

, in square miles aer a dnaL

, in square miles aer a dnaL

, in square miles aer a dnaL

, in square miles aer a dnaL

Figure 4. Persistent land loss and land gain across Louisiana by basin (as defined by the Coastal Wetlands Planning, Protection and Restoration Act Program, n.d.) and period for 1932–2010 (see map on page iv for color coding of periods).
10 Land Area Change in Coastal Louisiana from 1932 to 2010

1985 1990 1995 2000 2005 2010 2015

5,405

5,791

6,177

6,563

Katrina/Rita Gustav/Ike

L

a

n

d

are

a, in square miles

Year

95 percent confidence band, 

 1985–2010

Regression trend line, 

 1985–2010

Regression trend line, 1985–2004

Land area

Excluded data points, 2005–8

EXPLANATION

(r 2=

0.7208)

1985–2004 = 0.4969)

(r 2 1985–2010 = =

-11.76 ± 4.47

-16.57 ± 3.26 mi2

/year

mi2

/year

Figure 5. Linear regressions of land area change trends coastwide across 

Louisiana, 1985–2010; negative measurements indicate land loss, while positive 

measurements indicate land gain. Rates including and excluding the effects of 

the hurricanes of 2005 and 2008 are shown for comparison.

Variability in land area estimates can often be attributed 

to temporary wind and water level fluctuations present at 

the date and time of acquisition of the aerial and satellite 

imagery. Morton and others (2005) found that water area 

varied by as much as 5 percent over short time periods, largely 

as the result of environmental variability. The 17 dates of 

imagery analyzed provide a more robust estimate of change 

by reducing the inclusion of land area fluctuations caused by 

environmental variability.

 The desire to reduce errors associated with 

environmental variability was a driving force behind the 

development of the persistence criteria utilized in this analysis. 

An area must experience a change in land/water category, 

and that change must persist for at least two time periods 

following the initial conversion before that area is classified 

as “loss” or “gain”. The temporal resolution, as well as the 

persistence criteria used in this analysis, ensures that the data 

presented are more likely to represent permanent changes 

compared to previous studies; however, it is important to note 

when examining wetland loss/gain by time period that wetland 

areas often fluctuate between land and water categories. These 

fluctuations can take place for multiple time periods prior to 

a persistent conversion of an area from land to open water 

or, conversely, from open water to land. Consequently, loss 

that is shown to have occurred in a specific time period may 

have begun that transition in an earlier period. Initial losses 

often recover temporarily, only to be lost again because of 

a secondary or compound stressor. With the exception of 

anomalies, this assessment documents the last time period in 

which the persistent conversion occurred as opposed to the 

first time a change was documented. 

These analyses have shown that episodic events, such 

as hurricanes and other extreme storms, have contributed 

significantly to coastal land loss, particularly in recent years. 

Annual rates of coastal land loss for 1985 to 2010 (-16.57 ± 

3.26 mi2/yr) increased by approximately 4.8 mi2/year relative 

to the 1985 to 2004 trends (-11.76 ± 4.47 mi2/yr), reflecting 

hurricane-induced acceleration of coastal land loss. This is 

consistent with previous analyses described in Barras and 

others (2008). In addition to the immediate loss caused by 
Discussion and Conclusions 11

Atchafalaya Delta Basin

1985 1990 1995 2000 2005 2010 2015

116154192230268306

Gustav/Ike Katrina/Rita

, in square miles aer a dnaL

Barataria Basin

1985 1990 1995 2000 2005 2010 2015 849

926

1,0031,0801,1571,2341,3111,388

Gustav Katrina

, in square miles aer a dnaL

Breton Sound Basin

1985 1990 1995 2000 2005 2010 2015

232309386

Gustav Katrina

, in square miles aer a dnaL

Mermentau Basin

1985 1990 1995 2000 2005 2010 2015

579676773870967

Ike Rita

, in square miles aer a dnaL

Mississippi River Delta Basin

1985 1990 1995 2000 2005 2010 2015

77

115153

191

Gustav Katrina

, in square miles aer a dnaL

Pontchartrain Basin

1985 1990 1995 2000 2005 2010 2015

849887925963

1,0011,039

Gustav Katrina

, in square miles aer a dnaL

Terrebonne Basin

1985 1990 1995 2000 2005 2010 2015

1,0811,1581,2351,3121,3891,466

Gustav Katrina

, in square miles aer a dnaL

Teche-Vermilion Basin

1985 1990 1995 2000 2005 2010 2015

444463482501520

Ike Rita

, in square miles aer a dnaL

Calcasieu-Sabine Basin

1985 1990 1995 2000 2005 2010 2015

541618695772

Ike Rita

, in square miles aer a dnaL

Year Year Year

Year Year Year

Year Year Year

(r2 =

0.3909)

1985–2004 = 0.2758)

(r2 = 1985–2010 =

1.32 ± 0.811.22 ± 0.48 mi2

/year

mi2

/year (r2 =

0.7070)

1985–2004 = 0.6033)

(r2 = 1985–2010 =

-5.27 ± 1.62

-4.76 ± 0.97 mi2

/year

mi2

/year (r2 =

0.8126)

1985–2004 = 0.6544)

(r2 = 1985–2010 =

-1.97 ± 0.54

-2.98 ± 0.45mi2

/year

mi2

/year

(r 2

=

0.1009)

1985–2004 = 0.05010)

(r 2

= 1985–2010 =

0.67 ± 1.10

-0.97 ± 0.91mi2

/year

mi2

/year (r2 =

0.06836)

1985–2004 = 0.01922)

(r2 = 1985–2010 =

0.74 ± 2.01

-1.30 ± 1.52 mi2

/year

mi2

/year (r2 =

0.03195)

1985–2004 = 0.01624)

(r2 = 1985–2010 =

0.22 ± 0.65

-0.29 ± 0.51mi2

/year

mi2

/year

(r2

=

0.8437)

1985–2004 = 0.7054)

(r2

= 1985–2010 =

-2.44 ± 0.60-2.81 ± 0.38mi2

/year

mi2

/year (r2 =

0.6910)

1985–2004 = 0.5797)

(r2 = 1985–2010 =

-4.73 ± 1.52-4.37 ± 0.92 mi2

/year

mi2

/year (r2 =

0.3774)

1985–2004 = 0.1451)

(r2 = 1985–2010 =

-0.32 ± 0.29

-0.45 ± 0.18mi2

/year

mi2

/year

95 percent confidence  band, 1985–2010

Regression trend line, 1985–2010 Regression trend line, 1985–2004 Land area Excluded data points, 2005–8

EXPLANATION

Figure 6. Linear regressions of land area change trends in coastal Louisiana by hydrologic basin (as defined by the Coastal Wetlands Planning, Protection and Restoration Act Program, n.d.), 1985–2010; negative measurements indicate land loss, while positive measurements indicate land gain. Rates including and excluding the effects of the hurricanes of 2005 and 2008 are shown for comparison.
Publishing support provided by the

USGS Lafayette Publishing Service Center

direct physical impacts, hurricanes have been observed to 

induce excessive plant stress, such as from storm-driven 

elevated salinity and sulfides (Steyer and others, 2010), which 

has been suggested to contribute to future wetland losses. This 

analysis has shown areas that were not immediately observed 

as loss following a particular storm’s landfall, but those areas 

began to consistently appear as water several months later. 

Storm-induced stress likely contributed to at least some of the 

observed losses.

Excluding the high rates of wetland loss due to recent 

hurricanes, rates of wetland loss had been decreasing from 

the high rates observed in the 1970s. Britsch and Dunbar 

(1993) observed a similar trend of decreasing loss after 

1978. Though the wetland loss in coastal Louisiana is a dire 

situation, this observed decrease is at least a measured source 

of positive news, as past trends are often indicative of potential 

future losses.

An interesting finding of this analysis may be observed 

in the increase in net land area in the 2009 and 2010 datasets, 

as seen in figure 2. Though it may be intuitive to interpret 

this land area increase as recovery from the low, hurricaneinfluenced land area estimates of 2008, the potential 

influence of environmental variability dictates caution before 

interpreting this pattern as “recovery.” Discriminating the 

permanence of these increases from the transitory effects of 

environmental variability may require several additional years 

of observations. 

The temporal frequency of land change provided by 

this study is allowing scientists to further investigate the 

causal mechanisms of the loss that has occurred. These 

investigations will provide improved information to develop 

tools to monitor ecosystems, forecast possible impacts, and 

plan protection and restoration activities. These data can 

help support the development of strategies to adapt to our 

changing environment.

References

Barras, J.A., 2006, Land area change in coastal Louisiana 

after the 2005 hurricanes—A series of three maps: U.S. 

Geological Survey Open-File Report 2006–1274. (Also 

available at http://pubs.usgs.gov/of/2006/1274/.)

Barras, J.A., 2007, Land area changes in coastal Louisiana 

after Hurricanes Katrina and Rita, in Farris, G.S., Smith, 

G.J., Crane, M.P., Demas, C.R., Robbins, L.L., and Lavoie, 

D.L., eds., Science and the storms—the USGS response to 

the hurricanes of 2005: U.S. Geological Survey Circular 

1306, p. 97–112. (Also available at http://pubs.usgs.gov/

circ/1306/.)

12 Land Area Change in Coastal Louisiana from 1932 to 2010

Barras, J.A., Bernier, J.C., and Morton, R.A., 2008, Land area 

change in coastal Louisiana—A multidecadal perspective 

(from 1956 to 2006): U.S. Geological Survey Scientific 

Investigations Map 3019, scale 1:250,000, 14 p. pamphlet. 

(Also available at http://pubs.usgs.gov/sim/3019/.)

Bernier, J.C., Morton, R.A., and Barras, J.A., 2006, 

Constraining rates and trends of historical wetland loss, 

Mississippi River delta plain, south-central Louisiana, in 

Xu, Y.J., and Singh, V.P., eds., Coastal environment and 

water quality—Proceedings of the AIH 25th Anniversary 

Meeting and International Conference Challenges in 

Coastal Hydrology and Water Quality: Highlands Ranch, 

Colo., Water Resources Publications, LLC, p. 371–373. 

(Also available at http://coastal.er.usgs.gov/gc-subsidence/

historical-wetland-loss.html.) 

Britsch, L.D., and Dunbar, J.B., 1993, Land-loss rates—

Louisiana coastal plain: Journal of Coastal Research, v. 9, 

p. 324–338.

Britsch, L.D., and Dunbar, J.B., 2006, Land loss in coastal 

Louisiana 1932 to 2001—A series of maps: Vicksburg, 

Miss., Engineer Research and Development Center, U.S. 

Army Engineer District, New Orleans.

Louisiana Coastal Wetlands Planning, Protection and 

Restoration Act Program, n.d., Coastal Louisiana basins: 

Louisiana Coastal Wetlands Planning, Protection and 

Restoration Act Program Web site, accessed May 5, 2011, at 

http://lacoast.gov/new/About/Basins.aspx. 

Morton, R.A., Bernier, J.C., Barras, J.A., and Fernia, N.F., 

2005, Rapid subsidence and historical wetland loss in 

the Mississippi Delta Plain, likely causes and future 

implications: U.S. Geological Survey Open-File Report 

2005-1216, 124 p. (Also available at http://pubs.usgs.gov/

of/2005/1216/.) 

Steyer, G.D., Cretini, K.F., Piazza, Sarai, Sharp, L.A., 

Snedden, G.A., Sapkota, Sijan, 2010, Hurricane influences 

on vegetation community change in coastal Louisiana: U.S. 

Geological Survey Open-File Report 2010–1105, 21 p. (Also 

available at http://pubs.usgs.gov/of/2010/1105/.) 
ISBN 978-1-4113-3133-4

Printed on recycled paper 9 7 8141

1 3313 3 4

Couvillion and others—Land Area Change in Coastal Louisiana from 1932 to 2010—Scientific Investigations Map 3164