The Lakes of Pontchartrain: Their History and Environments

By Robert W. Hastings

A vital and volatile part of the New Orleans landscape and lifestyle, the Lake Pontchartrain Basin actually contains three major bodies of water—Lakes Borgne, Pontchartrain, and Maurepas. These make up the Pontchartrain estuary. Robert W. Hastings provides a thorough examination of the historical and environmental research on the basin, with emphasis on its environmental degradation and the efforts to restore and protect this estuarine system. He also explores the current biological condition of the lakes.

Hastings begins with the geological formation of the lakes and the relationship between Native Americans and the water they referred to as Okwa'ta, the “wide water.” From the historical period, he describes the forays of French explorer Pierre Le Moyne D'Iberville in 1699 and traces the environmental history of the basin through the development of the New Orleans metropolitan area. Using the lakes for transportation and then recreation, the surrounding population burgeoned, and this growth resulted in severe water pollution and other environmental problems. In the 1980s, the Lake Pontchartrain Basin Foundation led a concerted drive to restore the lakes, an ongoing effort that has proved significant.

• Language: English
• Publisher: University Press of Mississippi
• Release date: Mar 2, 2010
• ISBN: 9781626744356

Robert W. Hastings

Robert W. Hastings is a retired professor of biological sciences from Southeastern Louisiana University currently working for the Auburn University Environmental Institute and the Alabama Natural Heritage Program. His work has appeared in a variety of journals, and his conservation efforts in Louisiana have been recognized with numerous awards.

Book preview

The Lakes of Pontchartrain

The Lakes of Pontchartrain

THEIR HISTORY AND ENVIRONMENTS

Robert W. Hastings

www.upress.state.ms.us

The University Press of Mississippi is a member of

the Association of American University Presses.

Copyright © 2009 by University Press of Mississippi

All rights reserved

Manufactured in the United States of America

First printing 2009

∞

Library of Congress Cataloging-in-Publication Data

Hastings, Robert W.

      The lakes of Pontchartrain : their history and environments/

Robert W. Hastings.

         p. cm.

   Includes bibliographical references and index.

   ISBN 978-1-60473-271-9 (cloth : alk. paper) 1. Pontchartrain, Lake (La.)—Environmental conditions. 2. Pontchartrain, Lake, Watershed (La.)—Environmental conditions. 3. Pontchartrain, Lake (La.)—History. 4. Pontchartrain, Lake, Watershed (La.)—

History. I. Title.

GE155.L8H37 2009

508.763’34—dc22                                                 2009008875

British Library Cataloging-in-Publication Data available

Contents

Tables

Figures

Preface

Acknowledgments

The Lake’s Own Folk Song

The Lake’s Own Poem

Part 1

ENVIRONMENTAL HISTORY OF THE LAKE PONTCHARTRAIN BASIN

Introduction

1. Formation and Geology of the Pontchartrain Basin

2. Pre-European History

3. Initial European Exploration

4. European Colonization, Occupation, and Conflict

5. Louisiana Statehood

6. Civil War

7. Post-War Development

8. The Twentieth Century: Rapid Population Growth and Urban Expansion

Part 2

ENVIRONMENTAL MODIFICATION AND ABUSE OF THE LAKE PONTCHARTRAIN BASIN AND ITS RESTORATION

Introduction

9. Loss of Natural Habitats and Biodiversity

10. Water Quality Degradation

11. Environmental Recovery and Restoration

Part 3

CHARACTERISTICS OF THE LAKE PONTCHARTRAIN ESTUARINE SYSTEM TODAY

Introduction

12. Physical Description

13. Water Chemistry

14. Biota of the Pontchartrain Basin

15. The Estuarine Communities

16. The Marsh Communities

17. Estuarine Food Webs

18. The Palustrine Communities

19. The Riverine and Lacustrine Communities

20. The Terrestrial Communities

Postscript: Success?

References Cited

General Index

Taxonomic Index

Tables

Table 1 Major delta lobes of the Mississippi River

Table 2 Total population estimates of major Native American tribes occurring in the Pontchartrain basin between 1650 and 1908

Table 3 Population figures (and percentage change) for parishes bordering Lake Pontchartrain

Table 4 The natural communities of the Pontchartrain basin

Table 5 Historic vegetation types of the Florida parishes in the Pontchartrain basin

Table 6 Federally listed threatened and endangered species occurring in the Pontchartrain basin

Table 7 Land loss rates for the Pontchartrain basin

Table 8 Annual rates of shoreline change in the Pontchartrain basin

Table 9 Causes of land loss in the Pontchartrain basin

Table 10 Areal distribution of submersed aquatic vegetation in Lake Pontchartrain

Table 11 Openings of the Bonnet Carré Spillway and discharge amounts into Lake Pontchartrain

Table 12 Dimensions of Lake Pontchartrain and adjacent water bodies

Table 13 Shoreline types in the Pontchartrain basin

Table 14 Lake Pontchartrain place names from selected U.S. Coastal Survey nautical charts

Table 15 River inputs to Lake Pontchartrain

Table 16 Monthly average precipitation and rain days for New Orleans, Slidell, and Covington

Table 17 Natural and ecological communities of the Pontchartrain basin

Table 18 Plant species recorded at Delta Primate Center, St. Tammany Parish, Louisiana

Figures

Figure 1.1 Satellite photo of Lake Pontchartrain

Figure 1.2 Map of the Lake Pontchartrain basin

Figure 1.3 Delta lobes of the Mississippi River

Figure 3.1 The Cortes map of the Gulf of Mexico (c. 1520)

Figure 3.2 The Bisente map of the Gulf of Mexico (1696), Rio de Palisada, and Lago de Lodo

Figure 5.1 Manchac lighthouse

Figure 6.1 Coffee grounds on the western shore of Lake Pontchartrain

Figure 7.1 Logging ditches in the Manchac marshes

Figure 7.2 Water hyacinth (Eichhornia crassipes)

Figure 8.1 Population changes in the Pontchartrain basin, 1900–2000

Figure 8.2 Former camps and ruins at Milneburg (c. 1920) and Little Woods (2001)

Figure 8.3 Mandeville bulkhead and park

Figure 8.4 New Orleans lakeshore stepped seawall

Figure 8.5 The Bonnet Carré Spillway at the Mississippi River and at Lake Pontchartrain

Figure 8.6 The Pontchartrain Causeway

Figure 9.1 Shoreline erosion in Lake Pontchartrain

Figure 10.1 Tangipahoa River posted sign at Highway 443

Figure 10.2 Turbidity plume at mouth of the Tickfaw River

Figure 10.3 Algal bloom on north shore of Lake Pontchartrain

Figure 12.1 Lake Maurepas cypress shoreline near mouth of the Tickfaw River

Figure 12.2 Lake Pontchartrain cypress shoreline near mouth of the Tangipahoa River

Figure 12.3 Brackish marsh of marshhay cordgrass (Spartina patens)

Figure 12.4 Sand beach near Point Platte and Point aux Herbes

Figure 12.5 Rangia shell hash beach in Metairie

Figure 12.6 Metairie Linear Park

Figure 12.7 Riprap shoreline in Metairie

Figure 12.8 Riprap shoreline and old bulkhead at the Washout near Frenier

Figure 12.9 Bonnabel Canal pumping station in Metairie

Figure 14.1 Rangia cuneata shells near the mouth of Tangipahoa River

Figure 14.2 Harris’s mud crab (Rhithropanopeus harrisii)

Figure 14.3 The copepod Acartia tonsa

Figure 14.4 Bay anchovy (Anchoa mitchilli)

Figure 15.1 Cypress stump with Sphaeroma damage

Figure 16.1 Wildflowers of the Manchac marshes

Figure 18.1 Ancient cypress tree along the lower Tangipahoa River

Preface

The Lakes of Pontchartrain are three bodies of water, Lakes Borgne, Pontchartrain, and Maurepas, making up the Pontchartrain estuary in southeastern Louisiana. The lakes have a rich history, correlated with the exploration and settlement of the lower Mississippi River valley and the development and expansion of the New Orleans metropolitan area. In fact, New Orleans was located where it is on the Mississippi River primarily because of Lake Pontchartrain, and the Indian portage (by way of Bayou St. John) between river and lake. The Lakes of Pontchartrain have also been significantly modified by human impacts on the lakes, their tributary streams, and surrounding lands, which have resulted in major environmental problems. As New Orleans and other communities of southeastern Louisiana grew and developed, the quality of the lakes suffered. There is a tremendous assemblage of historical information regarding the lower Mississippi River and New Orleans, but the lakes have been largely neglected and overshadowed by the river and city. However, Lake Pontchartrain gained special prominence when in 2005 it was the source of flood waters that decimated the city of New Orleans in the aftermath of Hurricane Katrina.

This book describes the environmental history, biology, and characteristics of the lakes and their surrounding lands with regard to their modification, degradation, and restoration. By better understanding their environmental history, we can better understand how to protect and restore the lakes for future generations. Much has been written about Lake Pontchartrain, but no comprehensive description of its natural history has ever been published.

Many books provide excellent histories of New Orleans and Louisiana and include much information on Lake Pontchartrain. An intriguing book Lake Pontchartrain, written in 1946 by W. Adolphe Roberts, is primarily a history of the area and especially New Orleans, but it has much to say about the lake and its relationship to the city. Edna B. Freiberg’s Bayou St. John in Colonial Louisiana, 1699–1803 (1980) describes in detail the history of the bayou and its relationship to New Orleans and the lake. Frederick S. Ellis’s St. Tammany Parish: L’Autre Coté du Lac (1981) gives the north-shore perspective of the lake. Images of America: Lake Pontchartrain (2007) by Catherine Campanella is a photographic essay and memoir of life on the New Orleans lakeshore. Several somewhat comprehensive reviews of Lake Pontchartrain environments have been produced in recent years as efforts were initiated to restore the lake. These include Environmental Analysis of Lake Pontchartrain, Louisiana, Its Surrounding Wetlands, and Selected Land Uses (Stone 1980), Environmental Characteristics of the Pontchartrain-Maurepas Basin and Identification of Management Issues (Coastal Environments, Inc. 1984a), and To Restore Lake Pontchartrain: A Report to the Greater New Orleans Expressway Commission on the Sources, Remedies, and Economic Impacts of Pollution in the Lake Pontchartrain Basin (Houck et al. 1989). Other important references include the various environmental impact statements relative to shell dredging in the lake, the Bonnet Carré Spillway and diversion, hurricane protection projects, and other major construction affecting the lake (most done by or for the U.S. Army Corps of Engineers). Although very useful and providing a tremendous amount of valuable information, all of these reports are unpublished gray literature not readily available. The report by Tarver and Savoie (1976) is useful but somewhat limited in scope. The Lake Pontchartrain Basin Foundation (LPBF) prepared a comprehensive bibliography of literature on the lake (updated and made available at http://pubs.usgs.gov/of/1996/of96-527/). In 2001 the foundation, in partnership with the Environmental Protection Agency, U.S. Geological Survey, and the University of New Orleans, published its Environmental Atlas of the Lake Pontchartrain Basin (Penland et al. 2001a). John A. Lopez (2003) completed a doctoral dissertation at the University of New Orleans entitled Chronology and Analysis of Environmental Impacts within the Pontchartrain Basin of the Mississippi Delta Plain, 1718–2002. Most recently, The Nature Conservancy (2004) prepared a Conservation Area Plan for the Lake Pontchartrain estuary. These and other references on the lake provide a wealth of information regarding Lake Pontchartrain and its environments. Another source of information for those wishing to know more about Lake Pontchartrain is the Lake Pontchartrain Basin Maritime Museum and Research Center located on the Tchefuncte River in Madisonville.

One problem encountered when attempting a book of this nature is the dilemma of setting arbitrary boundaries for the area to be discussed. In the case of Lake Pontchartrain, its realm of influence includes the adjacent rivers, lakes, and sounds, as well as the marine waters of the northern Gulf of Mexico. To the north, it is greatly influenced by runoff from the numerous rivers and streams that make up its drainage basin, some of which extend some 70 mi. (113 km) north and into Mississippi. It is also significantly affected by flood waters diverted from the Mississippi River to the west and from the Pearl River to the east. On the terrestrial side, its adjacent wetlands give way to upland forest communities and urban developments that also impact the lake. My approach has been to focus on Lake Pontchartrain, with somewhat less attention given to Lakes Maurepas and Borgne, while providing somewhat arbitrary references to adjacent freshwater and marine areas. Terrestrial wetland areas are discussed as part of the lake system, but adjacent upland areas are included or neglected at my discretion.

The concept of this book began with a series of teacher workshops conducted at the Turtle Cove Environmental Research Station in Manchac, where I served as director for fifteen years. These workshops presented a survey of the history, geology, biology, and environmental issues of the Lake Pontchartrain estuary and its surrounding swamps and marshes, with the goal of providing teachers with local resource information to enhance their own classes in environmental education, biology, and earth science. Our rationale was that students learn best when presented with local examples to illustrate classroom principles, and students can even enhance discussions of some topics from their personal experiences. The Louisiana student may have no interest at all in the environmental protection of remote places such as Lake Erie or the Nile River, whereas students who have boated, fished, or bathed in Lake Pontchartrain or its tributary rivers can relate to the need for environmental protection of these local waters. Hopefully this account of the natural history and environments of the Lake Pontchartrain basin will provide any resident of the area, including teachers and students, with information to better understand this great natural resource.

Therefore, the book is dedicated to the many teachers who have instilled in their students a love for the natural history, environments, and culture of Louisiana and the Lake Pontchartrain basin. Included are my wife, Diana, and two daughters, Kimberly and Rachel, who have taught and supported me in all my endeavors.

"In the end we will conserve only what we love;

We will love only what we understand;

And we will understand only what we are taught."

—SENEGALESE ECOLOGIST BABA DIOUM

Acknowledgments

I thank Dinah Maygarden, Diana Hastings, and several anonymous reviewers who read and suggested improvements to early drafts of this book. In addition Sue Ellen Lyons and Sharon Flanagan (the Bwanettes) were faithful assistants and coinstructors for the teacher workshops that stimulated thoughts regarding the need for this book. Hayden Reno, station manager at the Turtle Cove Environmental Research Station, shared with me much of his first-hand knowledge of the Manchac swamps and their fauna. Robert Moreau and Mars Stouder, Turtle Cove employees, supported all of my endeavors while I served as research station director. Staff of the Lake Pontchartrain Basin Foundation, including Executive Director Carlton Dufrechou, former Environmental Director Neil Armingeon, Deputy Director Anne Rheams, and Director of the Coastal Sustainability Program John Lopez, were also especially helpful in supporting and encouraging my various activities on Lake Pontchartrain and guiding the restoration process for the lake. Bryan Rogers, formerly of the Lake Pontchartrain Basin Foundation, prepared the map included as Figure 1.2. I thank these and all others who have had a part in helping to restore the lake and its tributaries.

The Lake’s Own Folk Song

The Lakes of Pontchartrain

’Twas on one bright March morning I bid New Orleans adieu.

And I took the road to Jackson town, my fortune to renew,

I cursed all foreign money, no credit could I gain,

Which filled my heart with longing for

The lakes of Pontchartrain.

I stepped on board a railroad car, beneath the morning sun,

I rode the roads till evening, and I laid me down again,

All strangers there no friends to me, till a dark girl towards me came,

And I fell in love with a Creole girl,

By the lakes of Pontchartrain.

I said, "My pretty Creole girl, my money here’s no good,

But if it weren’t for the alligators, I’d sleep out in the wood."

"You’re welcome here kind stranger, our house is very plain.

But we never turn a stranger out,

From the lakes of Pontchartrain."

She took me into her mammy’s house, and treated me quite well,

The hair upon her shoulder, in jet black ringlets fell.

To try and paint her beauty, I’m sure ’twould be in vain,

So handsome was my Creole girl,

By the lakes of Pontchartrain.

I asked her if she’d marry me, she said it could never be,

For she had got another, and he was far at sea.

She said that she would wait for him, and true she would remain.

Till he returned for his Creole girl,

By the lakes of Pontchartrain.

So fare thee well my Creole girl, I never will see you no more, But I’ll ne’er forget your kindness, in the cottage by the shore. And at each social gathering, a flowing glass I’ll raise, And I’ll drink a health to my Creole girl, And the lakes of Pontchartrain.

—BARRY TAYLOR

(see http://www.geocities.com/sinker.geo/lakesofpontchartrain.html)

The Lake’s Own Poem

Lake Pontchartrain

Into thy sapphire wave, fair Pontchartrain,

Slow sinks the setting sun; the distant sail,

On far horizon’s edge, glides hushed and pale,

Like some escaping spirit o’er the main.

The sea-gull soars, then tastes thy waves again;

The bearded forests on thy sandy shore

In silence stand, e’en as they stood of yore

While yet the red man held his savage reign,

And daring Iberville’s adventurous prow

As yet had never cut thy purple wave,

Nor swung the shadow of his shining sail

Across the bark of the Biloxi brave.

Ah, placid lake! Where are thy warriors now?

Where their abiding places—where their grave?

—MARY ASHLEY TOWNSEND (1881)

Part 1

ENVIRONMENTAL HISTORY OF THE LAKE PONTCHARTRAIN BASIN

Introduction

In the southeastern corner of Louisiana and just east of the Mississippi River delta is a chain of lakes forming the Pontchartrain estuary, or the Lakes of Pontchartrain (Figure 1.1). The most significant of these is Lake Pontchartrain, a magnificent body of water closely tied to New Orleans and the Mississippi River delta by its environments, history, culture, and economics. With Lake Borgne (and Lake St. Catherine) on the southeast and Lake Maurepas on the west, these Lakes of Pontchartrain are located at longitude 89°30’ to 90°45’W and latitude 29°50’ to 30°30’ N (Figure 1.2). Lakes Pontchartrain and Maurepas were named by the French explorer Pierre le Moyne, Sieur d’Iberville, in honor of the two French dignitaries who had helped organize his expedition, Louis Phelypeaux, Comte de Pontchartrain, Minister of Marine for King Louis XIV, and his son Jerome Phelypeaux de Maurepas, the latter being the principal supporter of the expedition, who in 1699 succeeded his father as Minister of Marine (and later assumed the title of Comte de Pontchartrain). Antoine Simon Le Page du Pratz (1774), a historian who first visited Louisiana in 1718, stated that Lake Pontchartrain was called Lake St. Louis. Lake Borgne, which is actually an embayment of Mississippi Sound, was also named by the French (borgne meaning one-eyed or blind in one eye) because it is incomplete or defective without a complete shoreline, but instead a large opening to Mississippi Sound (Gayarre 1854). It has also been called Blind Lake (Freiberg 1980).

Narrow and deep natural passes connect the three lakes, and Lake Borgne opens into Mississippi Sound, which opens into the Gulf of Mexico, making the entire system an estuary where fresh water mixes with salt water. The major pass connecting Lake Pontchartrain and Lake Borgne is called the Rigolets, after the French word rigole (meaning channel, gutter, or drain and possibly signifying a stream flowing both ways, or tidal; Castellanos 1895; Darby 1816). The smaller Chef Menteur Pass just to the west also connects the two lakes. Several tales have been offered to explain the curious name of Chef Menteur Pass, which means lying chief. According to Gayarre (1854), the area and pass were named for a Choctaw chief who settled there after being exiled from Choctaw territory because of his habit of lying. According to Castellanos (1895), old people used to say that the Indians gave it the name of Big Liar, because it talked deceivingly. The adjacent Lake St. Catherine was once called Lake Chef Menteur (Romans 1774, in Phillips 1975) and Bay of Pines (1814 map by B. Lafon reproduced by Casey 1983, pl. 124, p. 422). Lakes Pontchartrain and Maurepas are also connected by two passes, Pass Manchac (also known locally as South Pass) and North Pass.

Figure 1.1 Satellite photo of Lake Pontchartrain (Used with permission of the Image Science and Analysis Laboratory, NASA Johnson Space Center, http://eol.jsc.nasa.gov; photo no. ISSO13-E-84678)

Figure 1.2 Map of the Lake Pontchartrain basin (Map prepared by Bryan E. Rogers)

The history of these lakes began long before the coming of the French, with their initial formation by geological events within the Mississippi River delta and their subsequent settlement by Native Americans, who depended upon the lakes as a source of food as well as for transportation routes. European colonization of the area was primarily correlated with use of the lakes, their passes, and their tributaries, as well as the Mississippi River, as transportation routes for commerce along the Gulf coast. With urbanization and increased population expansion, the lakes became the focus of major recreational activities but eventually were to be severely impacted by environmental abuse and modification of the surrounding natural areas. Environmental degradation finally stimulated a call for restoration that is still continuing today. The following chapters will trace the history of this environmental alteration (Parts 1 and 2) and conclude with a detailed description of the lake environment today (Part 3).

1.

Formation and Geology of the Pontchartrain Basin

The geomorphic history of the Pontchartrain basin begins some 5000 years ago (Saucier 1963, 1994), with its separation from the Gulf of Mexico by delta formation of the Mississippi River. Most of the following discussion of geology is taken primarily from Saucier (1963) and Darnell (1962), who provided a good overview of the lake’s origin and history. Saucier described the basin as a former embayment of the Gulf of Mexico modified by sedimentation from the shifting Mississippi River and its distributaries. From the time of its formation until the present, the Lake Pontchartrain system has been affected by the land-building forces of deposition and accretion more or less in balance with the destructive forces of faulting, subsidence, erosion, and redistribution of sediments. As described by Darnell, the geology of the basin is related primarily to fluctuations in sea level, migration and alternate delta formation by the Mississippi River, and continual subsidence of coastal deposits.

The higher lands to the north of Lake Pontchartrain, referred to as the Pleistocene Terrace or Prairie Terrace Complex, are much older than the lake. They were formed by deltaic deposition of material during interglacial stages of the Pleistocene epoch of the Late Quaternary period, which occurred some 60,000 to 100,000 years ago. These deposits also extend deep below the younger alluvial sediments of the Pontchartrain basin, all of which have been deposited by rivers in Recent (or Holocene) times (the last 15,000 to 35,000 years). The dividing line (referred to as the Baton Rouge Fault; Flowers and Isphording 1990) is marked by a distinct rise in elevation up to 2 ft. (60 cm) above mean sea level, with a continuous increase in elevation to the north. At one time this boundary was the shoreline of the Gulf of Mexico.

The southern boundary of the Pleistocene Terrace is also marked by a distinct change in sediment type. The Prairie Terrace sediments are largely well-oxidized silty to sandy clays, which may be red, yellowish brown, buff, or light gray, with little organic content. In contrast, the wet swamp and marsh sediments of the Pontchartrain basin proper have a very high organic content. There is also a marked contrast in vegetation types correlated with this sediment difference. The Prairie Terrace has been described as being covered originally by an almost homogeneous forest of longleaf pine (Pinus palustris) and slash pine (Pinus elliotti), with mixed hardwoods along the streams. This contrasts to the low marshy and swampy Recent sediments of the Mississippi River delta deposits (which have always been virtually devoid of pines; Saucier 1963). Although certainly oversimplified, such a description does demonstrate the dominance of longleaf pine in the upland areas north of Lake Pontchartrain.

The sediments in the Pontchartrain basin were formed by a combination of marine and riverine, or alluvial, influences. Those of marine origin are largely sand (0.0625–2 mm grain size), while those of alluvial origin are mostly silts and silty clays (less than 0.0625 mm). Rivers of the coastal plain produce their own natural levees (as well as deltas near their mouths) by the periodic flooding of their banks with sediment-rich water. The natural Mississippi River levees are about 2–3 mi. (3–5 km) wide and 20 ft. (6 m) above sea level at Donaldsonville and 1.5 mi. (2.4 km) wide and 12 ft. (3.7 m) above sea level at New Orleans. These levees are composed primarily of silt and clay, whereas the lower swampy areas are composed largely of organic matter such as wood fragments, or detritus. There is also a comparable though slight natural levee evident around the perimeter of Lake Pontchartrain and Lake Maurepas, where wave action has pushed up a ridge of flotsam bordering the lake shoreline. In some places, such as along the western side of Lake Pontchartrain, a remnant band of cypress trees remains on this slightly higher ground before receding into the lower marshes, where the trees were removed by logging in the early 1900s.

Lake Pontchartrain was formed some 3000 years ago, when sediment buildup from a former distributary of the Mississippi River separated the former Pontchartrain Embayment from the adjacent Gulf of Mexico. The river is known to have switched course east and west at intervals of about 1000 years, with at least five major delta complexes and sixteen delta lobes evident (Figure 1.3). There is some disagreement among experts regarding the number of delta lobes and their ages (Table 1). Regardless of how many deltas have formed, there is no doubt that active sedimentation from the Mississippi River was the major factor in the formation of Lake Pontchartrain. According to Saucier (1963), sedimentation rates have decreased during Recent times, but the sediment load of the river still averages about 500 million tons/year. Most of that sediment load is now carried into deep Gulf waters (because of the confining levees on the river), rather than building coastal lands in the delta.

Figure 1.3 Delta lobes of the Mississippi River (From Coastal Environments, Inc. 1984a based on original in Frazier 1967)

The location of an original shoreline or beach of the Pontchartrain Embayment is identified by the presence of a prominent sand ridge, the Milton’s Island Beach Trend, extending from the mouth of the Pearl River near Slidell to Ponchatoula (Saucier 1963). However, it is mostly buried beneath marsh, swamp, or lake-bottom deposits and is exposed only as Milton’s Island, a ridge of sandy soil covered with pine and hardwoods in the swamps and marshes near Port Louis just west of Madisonville. On the southern side of the Pontchartrain Embayment, another extensive beach deposit has been identified buried beneath Orleans Parish, the Pine Island Beach Trend (Saucier 1963) or New Orleans Barrier Island (Corbeille 1962; Stapor and Stone 2004). This formation is believed to represent a former barrier spit or series of barrier islands extending from near the present mouth of the Pearl River, which formed about 4500–6000 years ago from sand emanating from the Pearl River. Mollusk fossils indicate a shallow continental shelf habitat with higher salinities, suggesting the spit (or series of islands) was the open Gulf coast some 4000–5000 years ago (Rowett 1957; Saucier 1963; Otvos 1978b). These barrier islands began forming about 4000–7000 years ago by Pearl River deposits in the area now represented by eastern Orleans Parish (that is, the Pine Island Beach Trend). By 4500 years ago, the Mississippi River began influencing the area by adding fresh water and sediments to begin building the western portion of the Pontchartrain basin, or the St. Bernard delta (Saucier 1963). Fossil evidence shows that as salinity levels in the system decreased, the dominant mollusk species became more characteristic of lower salinities (10–30 parts per thousand [ppt]; Darnell 1962; Otvos 1978a). Approximately 3000 years ago, the existing Mississippi River course was established with one of its distributaries flowing to the east along the southern edge of the Pine Island Beach Trend. Formation of this Metairie Bayou–Bayou Sauvage distributary occurred about 1000–2000 years ago. This distributary would have built natural levees to form the land that is now known as Metairie-Gentilly Ridge (a part of the St. Bernard delta) and eventually creating the southern boundary of Lake Pontchartrain. By this stage the salinity of Lake Pontchartrain had become equivalent to what it is today, and the mollusk fauna was dominated by the brackish water rangia clam (Rangia cuneata) and dark false mussel (Mytilopsis leucophaeta), as well as two small hydrobiid snails (Texadina sphinctostoma and Probythinella protera; Darnell 1962; also see Solem 1961).

Table 1 Major delta lobes of the Mississippi River

Saucier (1963) postulated that much of what we now know as Lake Borgne would have been filled with sediments of the St. Bernard delta at the time of the delta’s maximum extent (2000–2400 years ago), and its subsequent development and enlargement resulted from subsidence and shoreline retreat. He also suggested that there was no open water representing Lake Maurepas when Lake Pontchartrain first formed, Pass Manchac was an old Amite River channel, and North Pass was the Tickfaw-Natalbany River channel. Lake Maurepas possibly formed later in a large depression between natural levees of Mississippi River distributaries and the Prairie Terrace. However, Saucier also recognized the possibility that Lake Maurepas represents a remnant of the Pontchartrain Embayment that was never filled by river sediment.

At present, the Mississippi River is again trying to switch back to the west and has begun to form a new Atchafalaya delta. This latest delta switch, exacerbated by the levees restricting the river flow to a relatively narrow channel, is now robbing the Pontchartrain basin, as well as the rest of the Modern delta, of the annual floods of nutrient and sediment-rich waters that have built and nourished the delta and its wetlands. Much of coastal Louisiana, including parts of the Pontchartrain basin, are inactive deltas (Louisiana Coastal Wetlands Conservation and Restoration Task Force 1997) and are being lost to subsidence and sea level rise. Estimated rates of land loss in coastal Louisiana of 35 sq. mi. (90 km²) per year are largely due to the combined effects of these natural processes plus the unnatural control of the Mississippi River. Considerable effort and expense has been dedicated to the conservation and restoration of coastal Louisiana, but most experts agree that the most effective way to accomplish this would be to restore the Mississippi River to a natural cycle of annual flooding of coastal marshes. Although some attempts have been made to do this, human developments in the delta now prevent a complete return to the natural system. Hopefully continued concern and research on this extremely complex problem will result in some degree of conservation and restoration.

2.

Pre-European History

Prehistory

When Lake Pontchartrain was visited by French explorers in 1699, the area had been inhabited by Native Americans for several thousand years. There have been 143 Indian sites recognized in the Pontchartrain basin (Saucier 1963). We have very little information regarding these earliest residents prior to 1700. Their impact on the lakes would have been minimal, except for the creation of large shell mounds, or middens, composed mostly of the discarded shells of rangia clams (Rangia cuneata) that were a major food item. However, Kidder (1998) suggested that there was significant selective burning of some areas to clear forest undergrowth, and later, as agriculture became more important, some land clearing for agriculture or construction of lodges. Of course, Native Americans were also gathering natural foods from the lakes, including clams, fish, turtles, and alligators, as well as game from the surrounding upland areas, but their relatively low population numbers assured a relatively minor impact compared to the much larger human population after 1700.

The earliest human occupation of Louisiana (the Paleo-Indian Period) dates back to about 10,000 B.C. (Neuman and Hawkins 1993), and people were present in the Lake Pontchartrain basin by about 1800 B.C. (Saucier 1963). Only a few scattered artifacts and sites provide evidence of their presence in the area up through about 600 B.C. These are identified with the Archaic, or Meso-Indian, Period (6000–2000 B.C.), and the Poverty Point Period, the first of the Neo-Indian Periods (2000 B.C. to 1600 A.D.; Gagliano 1963; Springer 1973; Cummins 1980; Coastal Environments, Inc. 1983; Neuman and Hawkins 1993).

These include the Bayou Jasmine site (Shell Bank Bayou) on the western side of Lake Pontchartrain just north of Frenier, the Linsley site between New Orleans and Lake Borgne near the junction of the Mississippi River Gulf Outlet and the Intracoastal Waterway, and the Garcia site on the shore of Lake Pontchartrain near the Rigolets (Gagliano 1963; Gagliano and Saucier 1963). Such sites are rare because of the relatively young age of the Pontchartrain basin, and any older sites would have been destroyed by the shifting channels of the Mississippi River delta (Haag 1978).

The Bayou Jasmine site is a midden mostly below sea level (16 ft. of a total 18-ft. thickness, 4.9 m of a total 5.5-m thickness) that rests on a submerged natural levee (Neuman 1976). Apparently the Bayou Jasmine community was a seasonal settlement, centered around fishing and gathering during the warmer months (Duhe 1976). The dominant foods were several species of fish (catfish, Ictalurus sp.; bowfin, Amia calva; alligator gar, Atractosteus spatula; longnose gar, Lepisosteus osseus; freshwater drum, Aplodinotus grunniens; freshwater bass, Micropterus sp.; crappie, Pomoxis sp.; and sunfish, Lepomis sp.), turtles (the snapping turtle, Chelydra serpentina, was most common), and alligators (Alligator mississippiensis). Clams (Rangia cuneata) were a basic food, although apparently not as nutritionally important as other foods (Byrd 1976). The dependence upon rangia clams was apparently related to their ease of capture and reliability, despite the low nutritional value (Neuman 1984). Numerous mammal remains included beaver (Castor canadensis), raccoon (Procyon lotor), rabbit (Sylvilagus floridanus and S. aquaticus), otter (Lutra canadensis), muskrat (Ondatra zibethicus), opossum (Didelphis virginiana), squirrel (Sciurus carolinensis and S. niger), dog (Canis familiaris), and deer (Odocoileus virginianus).

The subsequent period beginning in about 600 B.C. and marked by the presence of significant amounts of pottery (Cummins 1980) is referred to as the Tchefuncte (or Tchula) Period based upon shell midden sites excavated in the marshes on the north shore of Lake Pontchartrain in Fontainebleau State Park near the Tchefuncte River (Ford and Quimby 1945; Coastal Environments, Inc. 1983; Shenkel 1984). Others are the Big Oak Island and Little Oak Island sites in the New Orleans East area just south of Lake Pontchartrain, dated at about 600 to 100 B.C. (Gagliano 1969; Shenkel and Gibson 1974; Shenkel 1974, 1981, 1984). These people, living in groups of about twenty-five to fifty, were primarily a hunting, fishing, and gathering culture dependent to a large extent upon the rangia clams (37% by meat weight) and the clam-eating freshwater drum (40%), which were abundant in the lake (Shenkel 1984). Other important foods were deer (8%), other species