Armingeon, N. A., Lake Pontchartrain Basin Foundation, New Orleans, La,

THE BONNET CARRE' FRESHWATER DIVERSION REANALYSIS: SCIENCE VS. PORK BARREL POLITICS.

In 1973, a private citizen in Mississippi funded a study through the Business 

School at the University of Southern Mississippi to examine the effects of 

freshwater diversions on the fisheries of Coastal Mississippi.  Through political 

maneuvering, the small study grew into one of the nation's last, large civil works 

projects, the Bonnet' Carre Freshwater Diversion.  The proposed project would 

divert billions of gallons of Mississippi River water into Lake Pontchartrain to 

reduce salinities in a target area over 70 mile away at a cost to the taxpayer of 

over $200 million.

The project has been opposed by various groups since its inception, including 

commercial fishermen, the Louisiana Department of Natural Resources, all the 

parishes in the Pontchartrain Basin, and numerous environmental organizations.  

Despite the opposition, the project moved forward.  

Due to building public opposition, Congressman Bob Livingston directed the 

Environmental Protection Agency to undertake a complete reanalysis of the merits 

of the proposed project and its impacts to the ecological health of Lake 

Pontchartrain.  In December, 1993, a technical team was assembled to conduct an 

objective review of the project.  The group included scientists, regulatory 

agencies representatives, representatives of citizens groups and commercial 

fishermen.  

The reanalysis process initiated numerous studies which produced new data 

regarding the proposed diversion of the river water into Lake Pontchartrain.  The 

reanalysis included an experimental opening of the Bonnet Carre' spillway during 

May, 1994 which provided additional water quality data.  

Based upon the reanalysis findings, the technical committee recommended the U.S. 

Army Corps reduce the size of the original diversion by 70 percent.  The Corps was 

also directed to design a structure that would reduce nutrient loads in river 

water to meet water quality standards in the Lake.  In addition, the Corps was 

asked to investigate the placement of a sill or other modifications the Inner 

Harbor Navigation Canal to curtail saltwater intrusion into Lake from the 

Mississippi River Gulf Outlet (MRGO).  

The New Orleans District enlisted the aid of the Corp's Tidal Hydraulics Group to 

study the intrusion problem.  The group concluded: 1) the primary cause of 

increased salinity in Mississippi Sound and Lake Pontchartrain was the MRGO and, 

2) saltwater intrusion problems should be addressed at their source, the MRGO.

The District contracted with a private engineering firm to evaluate the overland 

flow design option.  The study indicated that to construct a project to meet the 

technical team's recommendations the cost of the project would increase by 54 

percent, from $81 million to $125 million.  

The reanalysis is scheduled to end mid-May, 1996.  The final results of the 

reanalysis process will be presented at the conference.       

Autin, Whitney J., Institute for Environmental Studies, Louisiana State University, 

Baton Rouge, LA 70803, and 

Mossa, Joann, Department of Geography, 3141 Turlington Hall, University of Florida, 

Gainesville, FL 32611

ENVIRONMENTAL SYSTEMS APPROACH TO FLOOD BASIN MANAGEMENT:  THE AMITE RIVER'S LINK 

TO THE PONTCHARTRAIN BASIN

The Amite River Basin drains part of southeastern Louisiana and southwestern 

Mississippi and empties into the Pontchartrain Basin, a link in the hydrologic 

cycle that has existed for the past ca. 5000 years.  This evolutionary 

relationship influences many of the present functions that sustain modern 

environments in the lower Amite and upper Pontchartrain basins.  Human landscape 

changes in the twentieth century have been imprinted upon the setting created by 

this millennia-scale natural evolution

Human modification of the Amite River Basin has been intensive, producing one of 

the most disturbed drainage basins in the northern Gulf of Mexico region.  Land 

use alterations include the conversion of natural  forest habitats to managed pine 

forests and agricultural land, urban/suburban growth of the Baton Rouge 

metropolitan area, significant stream channelization, and intensive flood plain 

mining for sand and gravel resources.  It has been suggested that stream 

channelization and flood plain mining have directly aggravated downstream flooding 

and increased stream turbidity.  These activities have induced a hydrologic and 

sedimentologic response that is only partly understood and not well quantified.  

It is likely that the system's physical response is triggering related ecological 

responses to terrestrial and aquatic habitats in both the Amite River and 

Pontchartrain basins.

However, the key public issue in the Amite River is the lower basin's flood hazard 

and the related inhibition of continued land development and suburban growth.  

Repeated large floods since 1977 and a record peak event in 1983 resulted in 

hundreds of millions of dollars in property damages and a public outcry for flood 

protection.  The primary flood hazard alternatives proposed to date are an upper 

basin reservoir to store flood water, a diversion channel to redirect flood flow 

to the Mississippi River, and trunk and tributary channel modifications designed 

to accept larger flows below bankfull stages.  Flood plain management and hazard 

mitigation strategies have received significantly less attention, in spite of the 

inability of engineering project proposals to pass the scrutiny of environmental 

impact and cost/benefit analysis.  Also, the public has expressed a lack of 

willingness to pay the costs associated with expensive engineering projects.

Environmental rehabilitation of the Amite River Basin may have benefits beyond the 

restoration of the surface hydrologic and sedimentologic balances necessary for 

self-sustaining terrestrial and aquatic ecosystems.  Mine reclamation of flood 

plain lands and reconstruction of meandering channel patterns to a pre-disturbance 

state could help to balance flood hydrology and sediment transport and increase 

the quantity and quality of flood plain habitat.  Watershed retention in upland 

tributaries could significantly trim the peakedness of the flood hydrograph and 

increase the quantity and diversity of permanent aquatic habitat.

The potential benefits of environmental rehabilitation in the Amite River, when 

blended with logical flood plain management, includes significant reductions in 

flood hazard, improvement in downstream water quality, and increases in ecological 

resources.  Such an approach is likely to be cost-effective, resolve significant 

public environmental management conflicts, and help the Amite River provide a 

self-sustaining, beneficial link to the ecological system of the Pontchartrain 

Basin.

Banbury,M.M., University of New Orleans, New Orleans, LA; 

Lyons, S.E., Holy Cross School, New Orleans, LA; 

Flanagan, S., Elaine P. Nunez Community College, Chalmette, LA; and 

Maygarden, D., Audubon Institute, Office of Environmental Policy, New Orleans, LA

PROJECT C.E.E.D.:  COASTAL EDUCATION FOR ECONOMIC DEVELOPMENT

Global warming, ozone depletion, hazardous waste disposal, nuclear holocaust, 

coastal erosion, habitat loss---all of these potential environmental disasters 

dominate human concern, but the question is always asked:  "What can I, alone, do 

to help the environment?"  Humans tend to see global environmental issues as 

something they can't control, yet they want to do something.  It is incumbent upon 

educational institutions to address that need, and it is best answered by (1) 

educating people about ecosystems and how they work, and (2) getting then 

involved, even tangentially, with decision-making and solutions.  Project 

C.E.E.D., developed to meet those goals, was a joint venture of the University of 

New Orleans (Department of Special Education and the Urban Waste Management & 

Research Center) and the Society for Environmental Education.

Project C.E.E.D. produced curriculum supplementary materials designed to introduce 

children to the basic concepts of wetlands education through a non-traditional 

approach.  In Welcome to the Wetlands: An Activity Book for Teachers, the authors 

have successfully combined important ecological information with a mix of 

challenging, fun, teaching activities.  Wetland Blues is a video designed to 

engage and entertain young people while giving them enough information about the 

value of wetlands to instill in them appreciation for this important environmental 

issue.  It is accompanied by Wetland Blues:  A Video Guidebook for Teachers, 

written for further student development of the problem-solving, decision-making 

skills necessary for contemporary environmental issues.  The final product of 

Project C.E.E.D. is a series of seven monographs, each of which explores a 

different facet of wetlands or wetlands-related problems.  Each activity book 

incorporates background information on the issue at hand, then involves children 

in designing a product that makes environmental learning fun and dynamic:  making 

buttons, designing T-shirts, writing poetry, taking social action, etc.

Project C.E.E.D. materials have been distributed widely at teacher workshops 

across the nation and have been extremely successful.  

Brent Barnidge, Lake Pontchartrain Basin Foundation, Metairie, La.

VALUATION OF LAKE PONTCHARTRAIN'S NORTHSHORE SEAGRASSES.

Seagrasses are naturally occurring subtidal vegetation which exists along the 

shallow coastline of Lake Pontchartrain.  They contribute to important biological 

and physical processes and form an intricate biological linkage with surrounding 

wetlands systems.  In addition, they provide for commercially and recreationally 

important species as a food source, shelter and habitat.

For years their ecological significance has been documented; however, an economic 

valuation -- to the detriment of the seagrasses -- has never been made.  Legal 

nonrecognition has continued to allow policy makers to erroneously assume that 

seagrasses possess little or no economic value.  In an effort to preserve the 

integrity of Lake Pontchartrain's surrounding marshlands, the Green Point/Goose 

Point Restoration Plan proposes revetment construction which will threaten the 

existence of the healthiest grassbed community in the lake.  While wetland 

protection is certainly a top concern in this state, the manner in which it is 

being approached will prove to be a costly and inefficient one.

Using information on the their contribution to finfish and shellfish production in 

the lake and surrounding waters, a monetary value per acre of the grassbeds can be 

determined; but, while we wait for a flawless value to be determined, the 

seagrasses could be lost forever.  A reasonable, justifiable value range can allow 

decision makers the opportunity to use their limited funding in a safer and more 

cost-efficient manner.  As a valuable renewable resource, the remaining northshore 

grassbeds make a substantial contribution to the local ecology and long-term 

economic stability of the region and warrant our protection.

Bianchi, T.S., and M. Argyrou, Dept. of EEO Biology, Tulane University, New Orleans, La.,

SPATIAL AND TEMPORAL VARIABILITY OF DISSOLVED AND PARTICULATE ORGANIC CARBON 

(DOC AND POC) IN THE LAKE PONTCHARTRAIN ESTUARY: THE USE OF CHEMICAL BIOMARKERS.

The Lake Pontchartrain estuary is a shallow-turbid estuary located on the northern 

Gulf coast.  While Lake Pontchartrain  is one of the largest  estuaries along the 

Gulf of Mexico and is situated adjacent to the city of New Orleans, very little is 

known about the carbon and nutrient dynamics of this system.  In 1995-96 we made 

bi-monthly samplings of  the  water column and sediments at nine stations that 

covered the full expanse of the estuary.   Total POC ranged from 0.2 to 0.5 mg/L 

while DOC ranged from 5 to 10 mg/L, and reached its highest concentration  in 

January 1996.  The percentage of DOC represented by high molecular weight DOC (HMW 

DOC or colloidal material), defined here as <0.2 m to > 3kD, was greatest 

(ca. 10%) at stations where freshwater inflow was high as well as wetland inputs.  

Pore-water concentrations of DOC averaged ca. 25 mg/L indicating that there was a 

net flux of DOC from  sediments to the water column.  Stations with the highest 

concentrations of pore-water DOC (i.e. 350 to 410 mg/L) typically had high 

densities of the bivalve Rangia cuneata.  Lignin-phenols (biomarkers of 

terrestrial plant sources) indicated that Lake Pontchartrain had higher 

sedimentary concentrations near regions where wetland inputs were high (i.e., 

Manchac Pass and the Tangipahoa River).  Moreover, terrestrial inputs to these 

sediments  were generally higher when compared to other estuaries along the 

northern Gulf coast.  Concentrations of PO4-3 and NH4+ were moderately high 

ranging from 1 to 2 mM and 3 to 12 mM, respectively.   However, total NO2- and 

NO3- concentrations were particularly low throughout most of the year with the 

highest concentrations occurring in January 1996 (10 mM ); with NH4+ representing 

the dominant form of inorganic N it is likely that sedimentary sources of N (via 

resuspension are important in this shallow-turbid system.  Despite these inputs of 

N, phytoplankton appeared to be light limited - as indicated by the generally low 

chlorophyll-a concentrations (3 to 6 mg/L) and high concentrations of suspended 

particulate matter (SPM) ( 3 to 24 mg/L).  Concentrations of the carotenoids 

fucoxanthin and zeaxanthin (measured by HPLC), indicated that diatoms and 

cyanobacteria were the dominant forms of phytoplankton in the estuary.   

Boshart,W. M., Department of Biological Sciences, Southeastern Louisiana University, Hammond, LA

MANAGEMENT STRATEGIES FOR MAXIMIZING GROWTH AND SURVIVAL OF BALDCYPRESS (Taxodium 

distichum (L.) Rich.) IN SOUTHEAST LOUISIANA.

Two study sites were used to compare different strategies for maximizing growth 

and survival of baldcypress. The first site is located in the vicinity of the 

Turtle Cove Environmental Research Station in the Manchac Wildlife Management 

Area.  Historically, this area was dominated by baldcypress (Taxodium distichum) 

swamp.  The area was commercially logged from the mid 1800s through approximately 

1950.  During this period, commercial interest was limited solely to timber 

harvest with no regard for long term ecological effects to these wetlands, nor 

were sustainable timber practices followed.  Pullboat logging techniques severely 

altered the landscape and thus the hydrologic regime of the area.  It is believed 

hat the natural regeneration of baldcypress has failed due to factors attributed 

to this altered hydrologic regime and compounded by the effects of herbivory.

In contrast is the second study site, located on the southeast bank of the Amite 

River in Clio, LA.  Riparian baldcypress forests were alternately clear-cut and 

select-cut during 1993.  No heavy equipment was used in the area during the timber 

harvesting process, therefore minimum damage appears to have occurred to the 

region.  The Clio site is almost continuously flooded, with the depth of the water 

varying due to precipitation, wind, and tidal effects. 

	

Two separate hypotheses were tested concerning baldcypress growth and survival in 

both study sites; direct comparisons were subsequently made between the sites.  

Hypotheses tested were management from competing vegetation, and quantity and type 

of limiting nutrients (nitrogen-phosphorus-potassium).  Both were tested with 

respect to differing age classes of baldcypress seedlings (twelve month, 

twenty-four month and thirty-six month).

Britsch, L.D., U.S. Army Corps of Engineers, New Orleans, LA; 

and Dunbar, J.B., Waterways Experiment Station, Vicksburg, MS,

NEW COASTAL LAND LOSS MAPS FOR LOUISIANA.

Land loss mapping and rate curve development for 62 quadrangles in the Louisiana 

Coastal Plain shows that land loss rates and trends vary significantly throughout 

coastal Louisiana.  Land loss rates for each quadrangle were defined for 4 time 

periods:  1930's to 1956-58, 1956-58 to 1974, 1974 to 1983, and 1983 to 1990.  

Differences in land loss rates among the individual quadrangles are a function of 

the geologic and hydrologic setting and the factors which contribute to land loss 

such as subsidence, storm induced erosion, channelization of streams and rivers, 

and canal dredging.  Of the 62 quadrangles mapped, 9 quadrangles are losing more 

than 1 percent of their land area each year, and 12 quadrangles are losing between 

0.5 and 1.0 percent per year during the 1983 to 1990 period.

On a regional scale, the land loss rate for the entire Louisiana Coastal Plain has 

decreased from an average yearly rate of 41.83 square miles in the 1956-58 to 1974 

period to 25.34 square miles during the 1983 to 1990 period.  The percentage of 

land being lost is also decreasing from 0.51 percent per year in the 1956-58 to 

1974 period to 0.35 percent per year during the 1983 to 1990 period.  The regional 

land loss rate will probably continue to decrease slowly until a background rate 

is reached.

In February 1996, the U.S. Army Corps of Engineers-New Orleans District published 

a map series summarizing this database in Technical Report GL-90-2 Land Loss in 

Coastal Louisiana (7 maps).

Burns, J. W., St. John's River Water Management District, FL, 

M. P. Poirrier, Dept. of Biological Sciences, Univ. of New Orleans, New Orleans, LA., 

and K. P. Preston, Dept. of Geography, Univ. of New Orleans, LA.

SUBMERSED AQUATIC VEGETATION AS INDICATORS OF WATER QUALITY IN THE LAKE 

PONTCHARTRAIN ESTUARY. 

 In response to the continued decline of submersed aquatic vegetation (SAV) in the 

Lake Pontchartrain estuary, SAV were experimentally transplanted in Lake 

Pontchartrain near Fontainebleau State Park, Bayou Lacombe, and Pointe aux 

Herbes.  SAV transplants were used to determine if water quality conditions were 

conducive to SAV survival and if transplanting was a viable technique for 

restoring submersed plants to areas where they had declined in response to natural 

disturbance.  

Vallisneria americana was selected for transplanting due to prior transplanting 

success with this species by others in low salinity estuaries and because of its 

historical dominance in Lake Pontchartrain.  Plants were harvested by hand near 

Bayou Lacombe (July 1994) and transplanted within 4 SAV enclosures at each site.  

Each enclosure measured 12 ft (l) x 12 ft (w) x 4 ft (ht) and was designed to 

baffle wave energy and to limit herbivory.  Plants were anchored to the sediment 

by hand with metal staples so that roots and rhizomes were completely buried.  

Within each enclosure, plants were placed in four circular plots at densities of 

50, 75, 100, and 125 shoots m-2 .  Each plant density was represented at each of 

four positions located within each corner of the enclosures.  Non destructive 

sampling techniques were used to determine transplant survival, species 

composition, foliar cover, plant density, blade length, and vegetative 

reproduction.  Sediment grain size and water quality parameters specific to SAV 

survival (bottom water temperature, pH, free carbon dioxide, alkalinity, salinity, 

specific conductance, and Secchi disk transparency) were also determined.

Transplanting V. americana in Lake Pontchartrain was successful due to the 

following observations: (1) shoots survived transplanting without signs of 

physiological stress; (2) shoots produced flowers, fruit, and viable seeds; and 

(3) there was a significant increase in SAV foliar cover due to growth and the 

vegetative reproduction of new plants.  Foliar cover, plant density, and blade 

length were greater at Fontainebleau during August 1994 sampling when compared to 

Bayou Lacombe and Fontainebleau.  Mean Secchi disk transparency was also greater 

at Fontainebleau during the study. However, initial transplants and new shoots 

were lost at Fontainebleau following a blue-green algae bloom in Lake 

Pontchartrain during June 1995.  SAV transplants were also lost at Pointe aux 

Herbes (November 1994) during extremely low water levels (ca. -3 ft.) that exposed 

transplants to desiccation.  Although SAV foliar cover increased from 10% to >80% 

at Bayou Lacombe between August 1994 and November 1995, there was no significant 

change in foliar cover following the blue-green bloom.

The spatial and temporal separation of the May 1995 flood and the June 1995 

opening of the Bonnet Carr( Spillway, provided us the opportunity to differentiate 

the potential independent biological consequences between flood waters from north 

shore rivers and streams and nutrient rich water diverted from the Mississippi 

River.  Distinct differences in water quality parameters (including pH, free 

carbon dioxide, and phenolphthalein alkalinity) were detected over the SAV 

transplants during these events.  The pH ranged from 6.1 to 9.8 at Bayou Lacombe, 

6.8 to 9.6 at Fontainebleau, and 6.7 to 8.3 at Pointe aux Herbes. This fluctuation 

in pH occurred between May 1995 and June 1995 following the May flood and June 

opening of the Bonnet Carr( Spillway.  Although free carbon dioxide concentrations 

ranged from below detection limits to 26 ppm between May and June 1995, there was 

no significant difference in mean free carbon dioxide concentrations for all sites 

during the study period.  Phenolphthalein alkalinity remained below detection 

limits at all sites except during June and July 1995 at Bayou Lacombe 

(2.0 + 0 ppm) and June 1995 at Fontainebleau (1.0 + 0 ppm).  Mean salinity for the 

study period was significantly greater at Pointe aux Herbes (3.9 + 0.4 ppt) when 

compared to salinity at Bayou Lacombe (2.7 + 0.3 ppt) and Fontainebleau 

(2.1 + 0.3 ppt).  Salinity ranged from 0.3 ppt to 6.8 ppt at Pointe aux Herbes 

(during July 1995), 0.1 ppt to 5.0 ppt at Bayou Lacombe, and 0.3 ppt to 5.7 ppt at 

Fontainebleau.  Low salinity for the study period was recorded at all stations 

following the opening of the Bonnet Carre Spillway.

Ideal conditions for the occurrence of a blue-green algae bloom in Lake 

Pontchartrain were met during June 1995.  Meteorological and water quality 

conditions prior to the algae bloom included: (1) max. air temperatures > 32 (C; 

(2) calm winds; (3) no precipitation for 29 days (3 June to 21 June 1995); (4) 

bottom water temperature > 30 (C in the littoral zone; (5) salinity < 1.0 ppt; and 

(6) increasing Secchi disk transparency.  With the input of additional plant 

nutrients to Lake Pontchartrain following the May flood and the June opening of 

the Bonnet Carr( Spillway, blue-green algae flourished in the estuary until the 

occurrence of Hurricane Erin.  Surface bloom-forming algae in the estuary best fit 

the description of Anabaena circinalis (Kutz.) Rabenhorst; a blue-green belonging 

to the Division Cyanophyta.  This species can be found in large rivers and ponds 

and is known to form "water blooms".  Fish kills were associated with the algae 

bloom but were isolated to urban outfall canals and Bayou Saint John where 

decaying algae was trapped between two water control structures within the bayou.

Data from this study suggest that SAV are excellent indicators of water quality 

and can be transplanted successfully in Lake Pontchartrain if water quality 

conditions are conducive to growth and reproduction.  The input of additional 

plant nutrients to Lake Pontchartrain, regardless of the source, may promote the 

increase of phytoplankton production and could cause further reduction of SAV.  

Physicochemical factors associated with Mississippi River water are not conducive 

to SAV survival in Lake Pontchartrain and directly contributed to the severity and 

duration of the blue-green algae bloom that occurred during June 1995.

Campo, F. M., Shaffer, G. P., and 

Llewellyn, D. W., Department of Biological Sciences, Southeastern Louisiana 

University, Hammond, LA

IN SITU HURRICANE SIMULATIONS ON TWO AGE CLASSES OF BALDCYPRESS (Taxodium distichum) 

(L.) (RICH) SEEDLINGS.

A tropical wave in August of 1994 created excellent conditions in the Manchac 

Wildlife Management Area, Louisiana, USA,  for conducting hurricane simulations. 

Eighteen-month old and forty-two-month old baldcypress seedlings were subjected to 

a range of in situ salinity pulses (ambient 1-2 ppt, 5 ppt, and 10 ppt) for 10 

days in the field.  Specifically, a large cylinder, pushed into the soil, was 

deployed around each of the seedlings as containment vessels for the salt 

solutions.  Basal diameters were measured before initializing the experiment and 9 

months after the cylinders were removed.  Photosynthetic measurements were taken 4 

days into the experiment in an attempt to capture the seedling's initial response 

to the salinity treatments.  Final photosynthetic measurements were taken 8 days 

after the cylinders had been removed (day 18).  Overall, 42-month old seedlings 

were more tolerant to increases in salinity.  However, photosynthetic rates across 

both age classes decreased linearly with increasing salinity.  Eighteen-month old 

seedlings exhibited stable diameter growth across salinity treatments, whereas the 

older seedlings paradoxically increased in diameter in the 5 and 10 ppt treatments.  

Soil redox potentials were significantly higher for the 42-month old seedlings 

across all treatments.  Among all units, there was not a single case of mortality.  

This field study provides direct evidence that baldcypress seedlings may be more 

salt tolerant than previous research has demonstrated.

Day, J. W., and Rybczyk, J., LSU, Baton Rouge, La., 

A. J. Englande, Tulane University, New Orleans, La., and 

Michael Dolese and Glenn Cooper, St. Bernard Water and Sewer Commission, Chalmette, La.

WATER QUALITY IMPROVEMENT USING COASTAL WETLANDS IN ST. BERNARD PARISH.

A study is currently being carried out to determine the potential effects of 

addition of storm water runoff and treated sewage effluent to the Poydras-Verret 

wetland in St. Bernard Parish.  This 4800 ha wetland has received a combination of 

secondarily treated municipal sewage effluent and street runoff from the Gore 

pumping station for a number of years.  In addition, the area is affected by 

Mississippi River water from the Violet siphon.  Wetland vegetation in the area 

ranges from swamps with cypress and Iva frutescens, to fresh marshes, to saline 

marshes dominated by Spartina alterniflora.  Cypress swamps formerly covered much 

of the area, but these were mostly killed by salt water intrusion from the 

Mississippi River Gulf Outlet.  The waste water discharge has freshened part of 

the area and allowed the maintenance of the swamp and fresh marsh communities.  

The current study is designed to monitor the impact of the discharge on the 

wetland ecosystem as well as changes in water quality due to overland flow through 

the wetland.  The study includes aspects of hydrology, soils, chemistry, 

vegetation, and animal populations.  Preliminary results indicate that the 

ecosystem is benefiting from the freshwater inflow and that water quality is 

improved.

Day, J. W., R. R. Lane, G. Paul Kemp, Brian Perez, and Joe Suhayda, LSU, Baton Rouge, La., 

Dennis Demcheck, USGS, Baton Rouge, La.  

OVERLAND FLOW OF MISSISSIPPI RIVER WATER IN COASTAL WETLANDS WITHIN AND 

SURROUNDING THE BONNET CARRE SPILLWAY.

The Bonnet Carre freshwater diversion project will divert water from the 

Mississippi River into Lake Pontchartrain via the Bonnet Carre spillway.  The 

original design of the project consists of a channel directly linking the two 

bodies of water.  A reanalysis was initiated to address concerns about the affects 

of the Bonnet Carre freshwater diversion on water quality and fisheries in Lake 

Pontchartrain.  The reanalysis included modeling of Lake Pontchartrain hydrology, 

possible affects on fisheries, diversion structure redesign, and the feasibility 

of overland flow through wetlands for nutrient and sediment reduction.  During the 

reanalysis process a short term experimental diversion was performed.  Overland 

flow in the Bonnet Carre spillway was minimal during the experimental diversion 

and a large volume of water was concentrated onto a small portion of wetlands.  

The general effect was negligible nutrient reduction and very high rates of 

accretion.  The experimental diversion suggests that a greater wetland area than 

is available in the spillway may be required to sustainably process the proposed 

Bonnet Carre freshwater diversion.  The amount of wetland area required, based 

upon naturally occurring loading rates of the Atchafalaya river basin, is 

available if wetlands within and adjacent to the spillway are utilized.

Day, J. W., R. R. Lane, LSU, Baton Rouge, La., 

B. Thibodeaux, Corps of Engineers, New Orleans District, New Orleans, La.  

WATER QUALITY ANALYSIS OF THE CAERNARVON FRESHWATER DIVERSION PROJECT.

Since 1991 Mississippi River water has been diverted at Caernarvon into Breton 

Sound.  Water quality was monitored at various locations in Breton Sound for four 

years prior to the diversion to the present.  Analyses of these data indicate 

reductions of nitrate, phosphate and suspended sediments as diverted water passes 

through Breton Sound waters and wetlands.  There is a slight increase in nitrite 

indicating denitrification is a pathway for nitrate reduction.  The area is a 

source for ammonia indicating active remineralization. The loss of nitrate is much 

greater than the increase in ammonia indicating that the area is a strong net sink 

for inorganic nitrogen.

Dufrechou, Carlton, Lake Pontchartrain Basin Foundation, Metairie, LA

RESTORATION OF THE LAKE PONTCHARTRAIN BASIN

The Lake Pontchartrain Basin Foundation (LPBF) is a private, non-profit 

organization dedicated to the restoration and preservation of the Pontchartrain 

Basin.  Pontchartrain is a complex system of physical and biological elements.  

The Basin drains almost 5,000 square miles of land in 16 Louisiana parishes and 4 

Mississippi counties.  It is home to over 1.5 million people.  The Basin forms one 

of the largest and most productive estuaries in the United States.  Discharges 

from agricultural activities, businesses, and communities with inadequate sewage 

systems released into streams, bayous, or rivers in upper reaches of the Basin 

eventually flow into Lake Pontchartrain.  Stormwater runoff from the highly 

urbanized south shore also drains into the Lake.  Eroding wetlands in the lower 

part of the Basin have increased saltwater intrusion into the Lake.

Management of Lake Pontchartrain requires management of the entire Basin.  

Regulating the Basin's environmental resources are 98 separate agencies and 

governing bodies.  The Lake Pontchartrain Basin Foundation through its 

Comprehensive Management Plan (CMP) coordinates the overall restoration.  The CMP 

attempts to balance and promote improvements to the Basin's water quality and 

habitats while recognizing the needs of the Basins Communities, businesses, and 

residents.

Flanagan, S. A., Nunez Community College, Chalmette, LA

WETLAND EDUCATION:  THE COMMUNITY COLLEGE CONNECTION.

Nunez Community College, situated in a fragile vanishing wetland area, provides 

educational opportunities for students in the surrounding area.  From its 

beginning in 1992, Nunez has offered a comprehensive course in wetland ecology.  

Students participate in a variety of lectures and experiential activities designed 

to acquaint them with the diverse wetland area in which they live.  Activities and 

instructional material rely on scientific data, incorporate multidisciplinary 

activities and encourage individualistic and creative participation by students.  

Models for instructional activities, student projects and class activities will be 

shared with interested educators.

Flowers, G.C. Department of Geology, Tulane University, New Orleans, LA 70118; 

Poirrier, M. A., Department of Biological Sciences, University of New Orleans, 

New Orleans, LA 70128; 

Suhayda, J. N., Department of Civil Engineering, Louisiana State University, 

Baton Rouge, LA 70803; 

Koplitz, L. V., Department of Chemistry, Loyola University, New Orleans, LA 70118; 

Clymire, J. W. and McPherson, G. L., Department of Chemistry, Tulane University, 

New Orleans, LA 70118.  

CHANGES IN THE WATER QUALITY OF BAYOU TREPAGNIER AFTER DIVERSION OF INDUSTRIAL DISCHARGE

On February 24, 1995, Shell Chemical Co., after receiving final regulatory 

approval from the Louisiana Department of Wildlife and Fisheries, diverted Norco 

Manufacturing Complex (NMC) effluent into the Mississippi River.  Removal of the 

Shell discharge from Bayou Trepagnier was the source of considerable anxiety for 

local environmental organizations trying to restore the bayou.  In particular, 

many were concerned that the reduction in flow at the headwaters would result in a 

stagnant waterbody with a high concentration of dissolved heavy metals.  

Environmental assessments completed on Shell's behalf indicated that water quality 

in the bayou probably would not be degraded by removing NMC effluent because it 

represented a minor part (2% of the discharge caused by tidal variation--the most 

important source of water level variation) of the total water budget.  This 

conclusion was based, in part, on observations made in the bayou during a 

three-day shutdown of the discharge in August, 1994.  In this experiment, water 

levels and water quality parameters were measured around the clock every four 

hours.  We repeated this study in August, 1995 in order to begin characterizing 

seasonal variations in bayou water quality.  Although the discharge was a minor 

component of the bayou's water budget, it significantly affected water chemistry.

One of the most obvious changes in the bayou from 1994 to 1995 is the significant 

decrease in temperature observed in the bayou headwaters.  Based on the Wilcoxon 

nonparametric test for independent samples, the mean temperature profiles for 1994 

and 1995 are different at the .05 level (two tailed test) for stations 5-35.  For 

station numbers greater than 35 there is no statistical difference between the 

temperature profiles for the two years.  In 1994, there was a salinity minimum in 

the vicinity of Stations 60-70 with salinity increasing both up and downstream.  

The 1995 profile, in contrast, shows a general decrease in salinity towards the 

headwaters.  Salinity profiles are statistically the same for Stations 30-45, 

55-60, and 130-160; salinity variation at a given station is less in 1995 than 

1994.  In 1994, the average pH was 7.63+ 0.24 (N=629) with the max and min being 

8.8 and 6.66, respectively.  After shutdown in 1995, the average pH was 6.7+0.14 

(N=658) with the max and min being 7.55 and 5.91, respectively.  Because the 

ranges for both data sets overlap only for stations near Lake Pontchartrain, there 

is little doubt that the differences observed before and after diversion of the 

discharge are statistically significant.  The profile for 1994 clearly shows an 

increase in pH toward the outfall, whereas in 1995 there is very little variation 

in pH along the bayou.  The average pH of bayou water in 1995 was approximately 1 

standard pH unit less than average values for 1994, and variability at each 

station was less in 1995 than in 1994.  In 1994, the average DO was 3.49+ 1.89 

(N=620) with the max and min being 12.15 and 0.1, respectively.  After shutdown in 

1995, the average DO was 2.87+1.79 (N=658) with the max and min being 0.1 and 

10.26, respectively.  There is no statistical difference between stations 5-25, 

35, 45-70, and 155 for the two years.  In the upper reach of the bayou, the DO 

content is either statistically equal or greater for 1995.  In 1994, only 3 

samples were analyzed for hardness (120 ppm as CaCO3 at 4;110 ppm at 75; 95 ppm at 

160).  In 1995, the average hardness of bayou water was found to be 362+ 23 ppm 

(N=9).  On the basis of chloride content, the average mass fraction of lake water 

in the bayou was 0.56+ 0.11 with the max and min being .75 and .38, respectively.  

In 1994, for the three bayou samples analyzed the average mass fraction was 

0.14+ 0.01.  In general, the water chemistry data suggests that the lake has a 

greater influence on the water chemistry of the bayou in the absence of the Shell 

discharge.  A proviso to this conclusion is that tidal magnitude (whether 

astronomical or wind driven) largely determines the degree to which lake water 

enters the bayou.

The biota of Bayou Trepagnier is composed of freshwater and estuarine species 

which are tolerant of low salinity and low dissolved oxygen.  The distribution and 

abundance of organisms has high seasonal and annual variation due to the presence 

of transient, estuarine species and movement of organisms in response to 

environmental change.  A direct measurement of the response of organisms to the 

diversion of the discharge by routine monitoring was not attempted because past 

studies of the distribution of fish and benthic invertebrates did not indicate a 

discharge effect, and because the high, natural variation in the system makes bona 

fide changes in the system difficult to detect.  It was assumed that any change 

which would result in more natural environmental conditions would be beneficial to 

the biota.  The decrease in temperature, salinity, and pH in the headwaters after 

diversion returned it to conditions typically found in natural tidal streams.  

Therefore, the diversion should have had a positive effect on the biota.

RECENT TRENDS IN WATER CLARITY OF LAKE PONTCHARTRAIN

Francis, J. C., and Poirrier, M. A., Department of Biological  Sciences, University 

of New Orleans, New Orleans, LA.

An apparent decrease in water clarity of Lake Pontchartrain  has been an 

environmental concern for several years.  The concern has been based in part on 

regression analyses of the available data on Secchi disk transparency in Lake 

Pontchartrain from 1953 to present time which indicate a statistically significant 

decrease in transparency with time.

Secchi disk transparency is influenced by both salinity and  wind speed.  A 

significant positive relationship exists between  Secchi disk transparency and 

salinity; a significant negative  relationship exists between transparency and 

wind speed.  In  addition, both variables realize pronounced annual seasonality.  

Salinity realizes its highest values in November and its lowest  values in May.  

Wind speed, on the other hand, realizes its  highest values in February and its 

lowest values in August.   These seasonal effects are not equally represented in 

the available data set on Secchi disk transparency in Lake Pontchartrain.  When 

the seasonal bias is removed from the data  set, it no longer supports the 

conclusion of a statistically  significant change in Secchi disk transparency from 

1953 through 1993.

An unbiased data set of Secchi disk transparency in Lake  Pontchartrain is 

available for the recent period 1986 through  1995.  The data include transparency 

values from stations along the Causeway bridge taken at regular monthly intervals.  

The seasonal effects of salinity and wind speed are thus adequately represented.  

These data suggest that although significant differences in transparency may exist 

at different sites in the lake at different times of the year, there has not been a 

statistically significant change in transparency over the period 1986 through 1995.

Gammill, S.P.,  Louisiana Department of Natural Resources, Coastal Restoration 

Division, Baton Rouge, LA.

OVERVIEW OF COASTAL RESTORATION PROJECTS IN THE PONTCHARTRAIN BASIN AUTHORIZED 

UNDER THE COASTAL WETLANDS PLANNING, PROTECTION, AND RESTORATION ACT OF 1990.

The Coastal Wetlands Planning, Protection and Restoration Act of 1990 (CWPPRA) 

directed that a Task Force comprised of representatives from the USACE, USFWS, 

NMFS, NRCS, EPA and the State of Louisiana develop a comprehensive approach to 

coastal wetland restoration and preservation in Louisiana.  The CWPPRA provides a 

maximum of $40 million, each year for ten years, for coastal wetland restoration, 

based on the state's ability to cost share.   The cost share ratio is 25% state 

and 75% federal.  Restoration plans were developed for nine major hydrologic 

basins in the state in 1993.  The CWPPRA Pontchartrain Basin restoration strategy 

calls for extensive bank stabilization along the Mississippi River Gulf Outlet 

(MRGO), reducing salinities in the basin with the Bonnet Carre Diversion and 

numerous small scale diversions, and preservation of the two land bridges 

separating Lake Pontchartrain from Lake Borgne and Lake Maurepas.  Since 1991, 

seven wetland restoration and protection projects in the basin have been 

authorized.  Cumulatively, these projects are expected to create protect and 

enhance approximately 8,000 acres of coastal marsh at a cost of roughly $17 

million with an average cost  per benefited acre of marsh of approximately $2,200.  

To date, one project, the LaBranche Marsh Creation Project, has been constructed 

and the remaining six are currently in various stages of planning, design or 

construction.   A variety of coastal restoration technologies are being utilized 

such as: 1)  marsh creation using dedicated dredging in the LaBranche Wetlands;  

2)  freshwater diversion outfall management at Violet in the Central Wetlands; 

3)  hydrologic management of impoundments in the Bayou Sauvage Refuge and at Eden 

Isles and; 4) shoreline protection to protect perched marshes along the MRGO.

Gurney, David, Southeastern Louisiana University, Hammond, La.

FECAL COLIFORM LEVELS IN THE TANGIPAHOA:  THE PRESENT SITUATION.

The Tangipahoa River was closed to swimming and boating in 1987 due to high fecal 

coliform levels in the water.  This paper examines the existing records on fecal 

coliform levels in the Tangipahoa, along with data on flow rates, water stages, 

and precipitation, to identify patterns and trends in current fecal coliform 

readings.

Hastings, Robert W., Southeastern Louisiana University, Hammond, LA

OVERVIEW OF PROGRAMS OF TURTLE COVE ENVIRONMENTAL RESEARCH STATION

Turtle Cove Environmental Research Station is a field research and educational 

facility of Southeastern Louisiana University located in the Lake Pontchartrain 

estuarine ecosystem.  Because of its location at the upper end of this major 

estuary, Turtle Cove is within one hour by boat of  various wetland environments, 

along with their aquatic counterparts, ranging from fresh to saline, including 

bottomland hardwood forests, cypress swamps, and marshes. Moreover, each of these 

habitat types exists in pristine, degraded, and restored states. The facility 

complements other field stations in the state (and nation) that are more concerned 

with higher salinity marine waters or fresh  waters.   Major environments present 

near Turtle Cove include estuarine and riverine aquatic systems, 

estuarine/freshwater ecotone, cypress/tupelo swamps, brackish, fresh, and 

intermediate marshes, and bottomland hardwood forests.

Activities at Turtle Cove address four major prioritized goals:  scholarly 

research,  university teaching, teacher training, and public service.  Major 

research areas include biogeochemistry, ecophysiology, estuarine ecology, 

hydrology, population biology, and restoration ecology.  Major educational 

programs include courses in estuarine and wetlands ecology, teacher training 

workshops, summer programs in science literacy, summer workshops for high school 

students, and field trips for K-12 school groups.

The Turtle Cove facility occupies  a three story wood frame building crafted of 

virgin cypress in 1908 as a private hunting and fishing lodge.  The facility is 

located on the Manchac Wildlife Management Area in St. John the Baptist Parish, 

Louisiana, along the south shore of Pass Manchac two miles west of Lake 

Pontchartrain. It has been  administered since 1981 by Southeastern Louisiana 

University  under a lease agreement with the Louisiana Wildlife and Fisheries 

Commission. The main building  contains a first floor research area, second floor 

living quarters with kitchen, bathrooms, and bedrooms  to sleep about 15, and 

third floor conference/class room and office. Since Turtle Cove is accessible only 

by boat, several vessels, including 25' lake skiffs as well as canoes,  are 

available for use by station visitors.  Boat sheds are located at Turtle Cove and 

five miles west of the research station along Galva Canal (shared with the 

Louisiana Department of Wildlife and Fisheries), where boats are kept for 

transportation to the station. Transportation for large groups is provided by a 

38' pontoon boat.  Various nets and other field equipment, as well as holding 

tanks (with aeration and filtration) for aquatic organisms, are available. 

Compound and stereo microscopes and other research equipment are also available.

Plans are being developed for the construction of new facilities at Turtle Cove, 

including a new research and educational building, additional housing facilities 

for both students and researchers, and  increased storage and maintenance space 

for boats. In keeping with SLU's image as a dynamic and rapidly growing institution 

of higher learning, Turtle Cove is also developing as an active research and 

educational facility. The overall goal is to make Turtle Cove a nationally 

recognized center for environmental education and research in low-salinity 

environments.

Hawes, Suzanne R., Corps of Engineers, New Orleans District

RESTORATION OF A MARSH IN THE LA BRANCHE PONDS - A CASE STUDY.

The La Branche wetlands on the south shore of Lake Pontchartrain in Louisiana were 

formed by the Mississippi River about 1,700 years ago.  The "prairie tremblante" 

(flotant marsh) near the lake was an uncultivated part of the La Branche 

plantation.  Between 1905 and 1910, an Illinois land developer bought over 8,000 

acres of these wetlands.  He dug canals, drained the land, and farmed truck crops.  

In September 1915, a hurricane with 140 mph winds along the coast, pushed large 

volumes of water into Lake Pontchartrain.  The tidal surge broke the levees and 

flooded the farm.

In 1990, Congress passed the Coastal Wetlands Planning, Protection, and 

Restoration Act in an attempt to restore coastal Louisiana which is losing 25 

square miles of marsh per year.  A Task Force made up of five Federal agencies and 

the State of Louisiana plans and implements the restoration process.  The Corps 

suggested creation of marsh in the La Branche ponds just north of I-10 and the 

project was approved in November 1991.  Even though this effort was expensive in 

terms of cost per habitat unit, it was selected because the Task Force felt that 

it was a showcase project.

From 1991 to 1993 a cost sharing agreement was worked out between the Corps and 

the State of Louisiana, and design work and environmental compliance were 

completed.  The planning was closely coordinated with the parish, landowners, and 

duck hunters.  Biologists determined that the optimum marsh elevation was 

between + 0.75 and + 1.34 NGVD and recommended that area be 70 percent marsh and 

30 percent ponds and bayous at the end of five years.  The maximum elevation of 

the dredged material was set at + 4 feet NGVD.  Preconstruction monitoring showed 

that the existing ponds contained abundant submerged aquatic vegetation dominated 

by water milfoil and coontail.  A rim of dwarf spikerush surrounded the shallow 

ponds.  The sediments of the ponds had a high water content and bulk densities 

ranging from 0.64 to 1.06 g/cc.  Organic matter ranged from 8 to 27 percent and 

the soil salinity was 3.5 ppt.

Originally, the borrow site was directly in front of the Bonnet Carre Spillway 

where the hole would refill quickly.  Further analysis showed that the material 

there was sand while the material in front of the marsh creation site was lighter 

and better suited for marsh creation.  The nearer site also reduced the cost of 

the project due to a shorter pumping distance.

The contract was awarded to T. L. James and Co. Inc. of New Orleans for $2,489,000 

on November 10, 1993.  They started construction of containment dikes in December 

and pumping began on March 7, 1994.  One month later, the area was filled.  They 

used a much larger dredge than anticipated which lowered project costs but caused 

some problems with material spillage.  Water exiting the area contained much more 

sediment than planned and began filling an adjacent canal.  A closure at the 

southern end of the canal was breached and the excess sediment filled a deep hole 

in a canal and spilled in the nearby Big Marlborough pond.  In July 1994, the new 

marsh was aerially seeded with 8,000 pounds of Japanese millet provided by the 

Natural Resources Conservation Service and St. Charles Parish.  Within a week the 

millet sprouted and by September it was producing seeds.

The first postconstruction aerial photography was flown on December 19, 1994, and 

showed 350 acres of new vegetation, 131 acres of existing vegetation and 34 acres 

of open water.  Over 20 species of emergent marsh plants were recorded.  

Approximately 20,000 waterfowl were reported to be using the site during the 

winter of 1994/5 and duck hunters did very well, especially during teal season.  

By the spring of 1995, a break had occurred in the containment levee on the 

southeast side allowing a few more natural ponds and bayous to be formed within 

the site.  These attracted wading birds and allowed some fishery access.  National 

Marine Fisheries Service requested that trenasses be dug to allow even more 

estuarine access.  An interagency group made a field inspection and determined 

that ponding of rainwater was keeping the area a wetland.  The group decided that 

trenasses would drain the area instead of adding water.  The sediment which 

spilled out of the weir formed a valuable mudflat in the Big Marlborough area and 

south of I-10.  These areas may colonize with plants during prolonged low water.  

However, they have caused problems for the local duck hunters who have trouble 

reaching their blinds.  They first requested that a channel be dug through the 

created marsh, but this was denied.  The Corps is pursuing the possibility of an 

access trenasse between the railroad and I-10.

Since project completion, the monitoring team has had problems accessing the 

site.  In the spring of 1994, they were able to place only 6 staff gauges because 

of logistical problems.  Readings were taken five times in 1994/5.  The reading 

indicated that the gauges were not reliable and thus they will not be used in data 

analysis.  In the spring of 1996, location markers will be placed and vegetation 

and sediment sampling will be initiated.

The pioneer plant in the spring of 1995 was a buttercup.  By summer, millet seeds 

from the previous year were sprouting and other wetland plants such as three 

square and wiregrass colonized.  On higher areas, shrubs came in.  Later in the 

year, camphorweed was present in large numbers and dwarf spikerush covered the 

lowest areas.  Alligators and nutria frequent the site as well as endangered 

species such as brown pelicans, peregrine falcons, and bald eagles.

Lessons learned from this project:

	-even with extensive sediment data, prediction of settled height is difficult;

	-monitoring needs to be aggressively pursued even if logistics are a problem;

	-close coordination with locals can occasionally lead to excessive expectations;

	-marsh can be successfully created from dredged material.

Hester, M. W., Department of Biological Sciences, Southeastern Louisiana 

University, Hammond, La., Mendelssohn, I. A., and McKee, K. L., Wetland 

Biogeochemistry Institute, Louisiana State University, Baton Rouge, La.,  

POPULATION VARIATION IN SALT TOLERANCE IN PANICUM HEMITOMON: MORPHOLOGICAL AND 

PHYSIOLOGICAL INVESTIGATIONS.

Plant material was collected from nineteen Louisiana populations of Panicum 

hemitomon (maidencane), a fresh marsh dominant.  Each population was vegetatively 

propagated from a single stem under uniform, non-saline conditions in a greenhouse 

for six vegetative generations to ensure that each population was represented by a 

single genotype and to alleviate any pre-existing acclimation to field salinity 

differences.  Five replicates of each population were potted in a commercial 

potting medium and plant morphometric measurements were obtained.  Populations 

were screened for intraspecific variation in salt tolerance by subjecting them to 

a weekly, stepwise salinity increase of 2 ppt until 50% death of aboveground 

tissue was observed, which we defined as the lethal salinity level.  Populations 

displayed highly significant differences (intraspecific variation) in lethal 

salinity level, which ranged from 7.6 ppt to 12.0 ppt.  Plant morphometric 

variables also displayed highly significant population differences, with several 

plant size characteristics showing significant positive correlations with salt 

tolerance.  Of these, leaf length and leaf area (of the two youngest expanded 

leaves per stem) were able to explain 43% and 46%, respectively, of the variation 

in lethal salinity level among populations.  To further investigate factors 

potentially associated with population differences in salt tolerance, we subjected 

a subset of six populations ranging from highly salt tolerant to poorly salt 

tolerant to a sublethal salinity excursion of 4 ppt and measured plant 

photosynthetic response, biomass partitioning, and numerous physiological and 

biochemical responses after one week (early harvest) and after five weeks (late 

harvest).  In the early harvest, highly salt-tolerant populations had 

significantly greater photosynthetic rates, midday leaf xylem pressures, 

aboveground, belowground, and total covariable-adjusted biomass than the poorly 

salt-tolerant populations.  Also in the early harvest, highly salt-tolerant 

populations displayed significantly lower leaf tissue cation concentrations, 

percentage dead tissue, and leaf proline concentrations (a stress metabolite and 

compatible solute that accumulates to significant levels only after a threshold of 

salinity stress is exceeded) than the poorly salt-tolerant populations.  By the 

late harvest, many of the physiological differences were no longer significant, 

with all populations displaying signs of cumulative salinity stress.  Nonetheless, 

in the late harvest the highly salt-tolerant populations were able to maintain 

significantly greater biomass production with less tissue death than the poorly 

salt-tolerant populations.  Greater salinity tolerance in the more highly 

salt-tolerant  populations of Panicum hemitomon appears to be the combined result 

of morphology interacting with an initially superior physiological response to 

salinity stress events.

Joseph, Jr. Randolph, Crowley, Louisiana, USDA-Natural Resources Conservation Service

WATER QUALITY INITIATIVES ON DAIRY OPERATIONS IN THE FLORIDA PARISHES OF LOUISIANA.

In 1987, the Louisiana Department of Environmental Quality and the Department of 

Health and Hospitals posted the Tangipahoa River and all of its tributaries 

against all primary and secondary water contract sports due to the high levels of 

the fecal coliform bacteria.  The sources of the bacteria were traced back to 

inadequate sewage treatment plants in towns and villages, inadequate septic tanks 

in rural areas, dairy operations in the immediate area, and dairy operations and 

urban areas from the State of Mississippi.

Because of the high priority of this water quality problem, state and federal 

agencies focused their attention on the problem and implemented programs to 

address the sources.  The agricultural industry including USDA and local soil and 

water conservation districts, focused on assisting dairy farmers in installing 

zero-discharge animal waste systems.  Special cost-sharing programs such as the 

Special Water Quality Incentive Program of 1988, the Middle Tangipahoa Land 

Treatment Watershed, the Louisiana Department of Environmental Quality Special 

Cost-Sharing Program and the Lake Pontchartrain Basin Foundation Cost-Sharing 

Program, were implemented to supplement the annual cost-sharing programs for waste 

management systems.

The Natural Resources Conservation Service (NRCS), formally the Soil Conservation 

Service, provide oversight on insuring that all systems installed met quality 

standards established by governing agencies.  As of February, 1996, according to 

figures gathered from the Louisiana Department of Health and Hospitals, Milking 

Division, approximately 501 dairies existed in the eight parish area.  To date, 

approximately 220 dairy operations have installed waste management systems through 

NRCS.  Once certified by NRCS, the dairy operation qualifies for cost sharing.  

The maximum cost-shared amount in most programs is $13,000.00.  However, in the 

Middle Tangipahoa Treatment Watershed Program, a producer may qualify for a 

maximum cost-share of up to $100,000.00.  The cost share rate of these programs 

may be 50/50 or 75/25; government to individual respectively.

Currently NRCS has approximately 100 dairy operations on schedule to install waste 

management systems within the next two years.  This leaves approximately 181 dairy 

operations still in need of technical and financial assistance.  Although test 

results do not show a proportional decline in the fecal coliform bacteria, lower 

averages and mediums have been recorded between 1988 and 1993.

Kendrick, D. Brian, Buchtel, James R., and Burkholder, David M., Louisiana 

Department of Natural Resources Coastal Restoration Division, Baton Rouge, LA

CONSTRUCTION OF A 7100' LONG SEGMENTED GEOTEXTILE TUBE BREAKWATER ALONG THE NORTH 

SHORE OF LAKE PONTCHARTRAIN.

In the late summer of 1996, the Louisiana Department of Natural Resources Coastal 

Restoration Division (LDNR/CRD) will begin construction of a segmented breakwater 

(State Project No. 4355NP4) along the Fontainebleau State Park shoreline for the 

LA Department of Culture Recreation and Tourism.  The breakwater is being 

constructed in response to a shoreline rate of loss of approximately 10 feet per 

year.  Funding for this project is being obtained from the state Mitigation Trust 

Fund and from private contributors.

The breakwater structure will be located in St. Tammany Parish and extend 

approximately 7100 feet from Bayou Castine and the City of Mandeville Harbor on 

the west to the Main Pavilion/Recreational Area of the park on the east.  The 

primary objectives of the breakwater are to protect the shoreline along Lake 

Pontchartrain and to prevent further breaching of a narrow strip of land between 

the lake and marsh to the north.  The breakwater will also prevent brackish water 

intrusion into the adjacent cypress marsh located within the State Park by 

providing soil accretion along the lake shoreline.   The structure will also 

provide an area of low wave energy to support submerged aquatic vegetation such as 

water-celery (Vallisneria americana) and fish and marine species such as speckled 

trout (Cynoscion nebulosus) and blue crabs (Callinectes sapidus).

The project will consist of eighteen (18) segmented geotextile tube structures, 

250-foot long, spaced approximately 100 feet apart, and two (2) continuous 

250-foot long tubes adjacent to the east harbor jetty.  The structures will be 

positioned approximately 300 to 500 feet from the existing shoreline.  The gap 

distance between each structure is designed to allow for some accretion of 

sediment along the shoreline.  A woven geotextile apron will underlie each 

structure to prevent erosion from undermining the tubes. Each tube will be 

approximately 25 feet in circumference (8' theoretical diameter) filled with 

imported sand or on-site dredged silty sand material.  The fill material will be 

stabilized using a 5% Portland cement with added geotextile fibers to increase 

tensile strength to prevent the possible damage of the tubes due to severe storms 

or vandalism.  The cement stabilized material will be pumped into the tubes with 

only a minimum release of material expected through the fabric.  It is estimated 

that approximately 10,000 cubic yards of material will be required to fill the 

estimated 20 tubes.

The project has received permits from the Louisiana Department of Environmental 

Quality (Water Quality Certification), the LDNR (Coastal Use Permit) and the 

United States Army Corps of Engineers (Section 10/404 Permit).  The entire 

7100-foot project length is included under one permit; however, construction may 

be in phases due to limited funding.  The breakwater foot print will cover 

approximately 1 to 1 acres of state water bottoms over the project length.  

However, over 75 acres of state water bottoms and 7100 linear feet of shoreline 

will be protected from further erosion and degradation.

Kenwood, Clifford M., Lake Pontchartrain Basin Foundation, New Orleans, LA

USING THE INTERNET FOR ENVIRONMENTAL EDUCATION AND ADVOCACY.

The Lake Pontchartrain Basin Foundation currently operates a world wide web site 

at http://www.brecht.com/saveourlake/.  The site serves three primary purposes: 

education, advocacy and development.

Visitors to the site are greeted by a live video image of Lake Pontchartrain.  The 

site also features a satellite photo of the Pontchartrain Basin that is divided up 

into areas that visitors can "click" to access information on that geographical 

region.  For example, if the area marked "Grassbeds" is clicked, an image of the 

lake's seagrasses appears along with text on the subject.

The site will also feature an advocacy page where net-surfers can e-mail elected 

officials on critical issues directly from the page.  For example, if comments are 

being solicited on a permit, users can click a button to send an e-mail on the 

subject.  Future plans include using the site as a repository for water quality 

data.

The site will be displayed "live" to show its functions.  Design and maintenance 

of the site was donated by Pertuit Online Marketing Service, Inc. of Metairie.

Clifford Kenwood,   Lake Pontchartrain Basin Foundation, Metairie, LA 70009-6965; 

Frank T. Manheim  U.S. Geological Survey, Woods Hole MA 02543,  and 

S.Jeffress  Williams, U.S. Geological Survey, Reston, VA 22092

AN UPGRADED ENVIRONMENTAL AND GEOLOGICAL BIBLIOGRAPHY FOR LAKE PONTCHARTRAIN

A  bibliography relating to environmental science information on Lake 

Pontchartrain  was compiled by the Lake Pontchartrain  Basin Foundation (LPBF) for 

a research symposium  in 1992. This  bibliography, encompassing approximately 2000 

titles, has been converted to a desktop computer spreadsheet / database format.  

The work was done in cooperation with USGS, which has begun further bibliographic 

research as a part of a broader cooperative study of the Lake Pontchartrain Basin 

(LPB).  

The LPBF reference list is based in part on earlier bibliographies by Mary G. 

Curry (1984, with updates in 1986 and 1987), and by Rod E. Emmer in 1984-5. The 

references were mainly in brief, 6-field ASCII text format, including keywords. 

Many items refer to newspaper, government or survey reports that are not widely 

distributed but may have importance for full documentation of the LPB environment. 

The following provisional list summarizes included subjects: bibliography, 

biology, chemistry, contamination - pollution, economics, engineering, erosion, 

geology, history, hydrology and floods, overviews, municipal affairs, petroleum, 

planning, political and legal, and wetlands.

USGS staff will coordinate entering supplementary references in standard desktop 

bibliographic software format.  This includes large National Technical Information 

Service (NTIS) documents from the U.S. Army Corps of Engineers and other federal 

agencies, Louisiana State agency documents, journals, dissertations and other 

sources. When completed, the two databases will be merged.  Dr. Shea Penland, of 

the Louisiana State University Coastal Studies Institute will be involved in the 

work, and additional cooperators are welcomed.

Desktop bibliographic software permits comprehensive search capability and 

automatic output into common publication and database formats. Retrieval of needed 

titles and referencing for reports is faster and more accurate and consistent.  

The envisaged bibliography is designed to be available in widely accessible 

desktop spreadsheet or database software computer formats and to permit users to 

expand reference subsets with their own supplementary references and research notes.

Koplitz, Lynn Vogel; Nguyen, Anh, Department of Chemistry, Loyola University, New 

Orleans, LA 70118; and Flowers, George C., Department of Geology, Tulane 

University, New Orleans, LA 70118; and McPherson, Gary L.; Clymire, Joe; 

Dowling, Jeff; Ramirez, Suzie; Washington, Will, Department of Chemistry, Tulane 

University, New Orleans, LA 70118

SEDIMENT CONTAMINANT PROFILES IN BAYOU TREPAGNIER BEFORE AND AFTER DIVERSION OF 

INDUSTRIAL EFFLUENT

The Pb, Cr, Cu, and Zn contents of sediments and associated pore waters at 27 

sites along Bayou Trepagnier were determined in June 1994 and again in June 1995 

from grab samples.  Sediment acid volatile sulfide (AVS) values, an indicator of 

the ability of sediments to scavenge dissolved heavy metals from the water column, 

were also measured both summers.  Effluent from the Shell Norco Manufacturing 

Complex entered the bayou at its headwaters until late February of 1995 when it 

was diverted to the Mississippi River as required by the USEPA.  Hypotheses 

offered herein to explain observations are based primarily on these two data sets 

for samples collected one year apart.  These suggested explanations will be tested 

in part by analysis of data to be collected in a similar fashion this coming June 

1996.

In general, concentrations of all four contaminants are relatively low near the 

former effluent outfall (site 0), increase to maximum values in the upstream third 

of the bayou (sites 20-60), then gradually fall to background levels near the 

confluence with Bayou LaBranche (site 160).  (Note that each site marker indicates 

an additional 100 ft. downstream.)  From '94 to '95 lead, copper and chromium 

values fell markedly in the upper third of the bayou (sites 0-50).  The analytical 

concentration of Pb and Cu at site 0 decreased by about half while Cr went down to 

about one-fifth of its '94 value.  Zinc sediment concentrations decreased most 

between sites 24 and 64, generally declining by about 20-25%.  High lead values 

found at sites 16 (1540 ppm), 72 (995 ppm) and 88 (786 ppm) in '94 were far lower 

in '95 (all ~300-350 ppm).  However, lead and chromium were appreciably higher 

(Pb up to 1500 ppm from 350 ppm, Cr up to 750 ppm from 250 ppm) downstream at site 

104 in '95, and chromium increased markedly at sites 48 (up to 1220 ppm from 385 

ppm) and 80 (up to 1350 ppm from 750 ppm).

These observations may indicate deposition of material downstream from an upstream 

area of suspension, or dissolution, either due to physical factors such as 

abruptly decreased flow allowing suspended material to drop out of the water 

column, or because of changes in water chemistry from mixing with tributary water 

causing insolubility and precipitation of certain metal phases.  For sites 

110-160, the last mile of the bayou closest to Lake Pontchartrain, all four 

contaminant distributions were essentially unchanged from '94 to '95, suggesting 

that any suspended or dissolved material did not migrate to or through this end of 

the bayou.  If release events are occurring, they are probably short-lived and 

extend only a short distance since AVS is abundantly available to scavenge 

dissolved heavy metals. Monthly monitoring of bottom water does not show high 

levels of dissolved (filterable) metals.

Pore water and sediment concentrations for individual metals are not correlated 

except in the case of chromium (r2 = 0.605 for a linear least squares fit of pore 

water vs. sediment values, '95 data).  Zinc and copper sediment values show strong 

correlations with themselves from '94 to '95 (94/95 Zn r2 = 0.874, Cu r2 = 0.717), 

while lead and chromium are not well correlated between years (Cr r2 = 0.300, Pb 

r2 = 0.081).  These observations and the previous discussion indicate that 

multiple dominant modes of contaminant transport (e.g. suspended particulates, 

adsorbed, or dissolved species) are operating in the bayou.

Lead seems to be influenced extensively by inputs from the adjacent spoil banks.  

Elutriate tests performed with spoil bank samples show the highest release of lead 

from solid to filtered "dissolved" fraction (passes 0.45 m filter) at the spoil 

bank sites with the highest lead levels.  Sediment samples for this study were 

collected near the western side of the bayou close to the site markers.  For June 

1994, the lead distribution pattern in the bottom sediments is similar to that of 

the spoil banks.  However, the June 1995 samples do not display this pattern and 

more closely resemble the distribution shown by mid-channel samples collected in 

early 1994 and analyzed by EA Environmental Consulting for Shell.  These facts 

imply a homogenization of lead over the channel cross section, probably due to 

suspension and redistribution by motor boats.

Preliminary MINTEQA2 model calculations show that truly dissolved phases are not 

responsible for the pore water metal concentrations since the calculated values 

are at least three orders of magnitude lower than those found by GFAAS analysis.  

However, the analyzed samples probably contain colloidal particles that pass 

through the 0.45 m filters and become dissolved by strong acid added later.  This 

microcolloidal phase, which may also contain appreciable amounts of adsorbed heavy 

metal species, is a current focus of investigation.  In addition, dissolved 

organic matter (DOM) may account for some of the dissolved metal load given the 

obviously high concentration of DOM indicated by the tea color of the water.  

Including generic DOM in the MINTEQA2 calculations had no effect on dissolved Cu2+ 

or Cu1+, but it raised the solubilities of Zn2+ and Cr3+ by about a factor of 10, 

and increased the total dissolved Pb2+ by about 200 times.

From 2/94 to 6/94, Pb increased from 400 ppm to 1000 ppm at a site in Engineer's 

Canal adjacent to a small cross channel connecting it to Bayou Trepagnier.  Recent 

intense studies of Bayou Trepagnier by at least five different research groups 

have been accompanied by heightened motor boat activity in the bayou and canal.  

This activity may account for some, or most, of the observed redistribution of 

sediment contaminants.

List, Jeffrey H. and Signell, Richard P., U.S. Geological Survey, Woods Hole, MA

WAVE MODELING IN LAKE PONTCHARTRAIN.

The currents associated with wind-generated waves are likely to be the primary 

cause of sediment resuspension in Lake Pontchartrain. Wave-induced resuspension 

enables transport by weak steady flows and may have a strong influence on the 

overall distribution of bottom sediment types in the basin.  In order to better 

understand the distribution of bottom sediment types and to predict the transport 

and deposition of these sediments, we applied the wave prediction model HISWA 

(Hindcasting Shallow-Water Waves) to Lake Pontchartrain.

The HISWA model is uniquely suited for modeling waves in restricted basins like 

Lake Pontchartrain because it accounts for the local generation of waves by wind 

and it simulates shallow-water effects on waves including refraction, shoaling, 

bottom friction, and breaking.  HISWA's ability to simulate waves in Lake 

Pontchartrain is evaluated through comparisons with field data collected at three 

sites within the basin in the spring and summer of 1995.  Correlations between 

measured and predicted waves are generally high, especially for wind events 

lasting more than one day.

Several applications of HISWA to studies of the basin's sediment distribution are 

presented. For individual storm events, HISWA predictions are compared with 

satellite imagery showing the patterns of suspended sediment.  This provides an 

assessment of the degree to which model results can be used for predicting the 

initiation of sediment resuspension in the basin.

In addition, HISWA simulations using a wide range of wind speeds and directions 

are weighted with statistics from long-term wind observations to give the regional 

"climate" of bottom orbital velocity (showing the spatial and temporal variability 

of wave-induced currents at the bottom).  The degree to which this orbital 

velocity climate controls the distribution of sediments within the basin is 

evaluated through comparisons with maps of bottom sediment type.

Lopez, John A., Amoco, New Orleans, Louisiana

Historical Oil and Gas Production in Lake Pontchartrain.

Lake Pontchartrain is significantly less productive in oil and gas production 

compared to the rest of south Louisiana.  This is probably due to its lack of 

geologic complexity and its unique geologic setting.  Eight of nine fields in the 

Lake are clustered in the southwest corner in closest proximity to more typical 

South Louisiana geology.  Only one or two small gas fields have been found in the 

Northern half of the Lake.  Over  30  years of drilling, approximately 103 billion 

cubic feet of gas and 8.5 million barrels of oil have been produced from the Lake.  

Approximately 120 exploratory wells and 35 development wells have been drilled in 

Lake Pontchartrain.  This has resulted in 46 producing wells in nine fields with 

an average field size of 16 billion cubic feet of gas.  The largest field is Block 

41 which has produced approximately 47 billion cubic feet of gas.  This largest 

field in 348th in field size rank for South Louisiana oil and gas fields.   As of 

1995, 22 wells were active with total production  of 9 million cubic feet of gas 

per day and a small amount of oil.  Most exploratory wells have targeted the 

Miocene,  but there are 10 deep wells in excess of 15,000 feet.   There are also 

several active gas transmission lines,  but no oil pipelines in the Lake.  Oil and 

condensate produced in the lake has traditionally been transported by barge at 

approximately 10,000 barrels per load.   On average,  South Louisiana is expected 

to produce   1.3 million barrels Oil (barrels of oil equivalent) per square mile. 

Lake Pontchartrain has produced 46,000 barrels oil (barrel of oil equivalent) per 

mile.  Lake Pontchartrian has production is less than 1/20th of normal oil and gas 

production in south Louisiana.

Why is Lake Pontchartrain 20 times less productive than the rest of South 

Louisiana?  Lake Pontchartrain happens to overlie a geologic region which is in a 

transitional position between two major geologic provinces.  The Lower Cretaceous 

margin and platform lie northward of the Lake and has low production.   The 

typical south Louisiana salt dome and growth faulted Tertiary basin lies southward 

of the Lake and New Orleans.  In between and underneath the Lake is the margin of 

the Tertiary basin.  Salt domes -- so prolific elsewhere -- are not present 

beneath the Lake.  Major growth faults are also absent and consequently 

significant rollover structures are absent.  Lake Pontchartrain lacks the 

traditional key geologic features for major oil and gas production. 

Although there have been environmental incidents from the oil and gas activities 

in the Lake,   the total  environmental impact from all these activities is minor 

or  negligible.  There was a minor oil spill of approximately 10 barrels of oil 

(420 gallons to the public) in 1992.  In addition,  in 1990 one operator was 

discharging produced water without a discharge permit.  The latest incident was in 

1993 when a 1 barrel spill was reported.  Even with these more "significant" 

incidents no direct environmental damage has been documented.  Other less 

significant incidents have occurred with  apparently  no observable  impact.  In 

spite of this record,  there are still environmental risks associated with oil and 

gas activities within the lake.  First,  existing facilities have deteriorated and 

there is evidence that they have not been properly maintained.  Second, 

traditional oil and condensate are barged out of the Lake.   Barging oil is 

considered a relatively risky mode of transport by posing the risk of an oil spill.  

Third,  drilling exploratory wells, especially deep, poses a  risk of blowouts and 

spills.  Simply because there has not been a truly significant incident in the 

past,  it is unwarranted to say that there is absolutely no environmental risks 

now or in the future.  In addition the Lake and its estuaries are relatively 

vulnerable due to the Lake's restricted interchange to other water bodies.  How 

likely is a significant environmental incident ? . . . how great is the potential 

impact?  These are legitimate questions which should be discussed openly.  Such 

discussion should consider the unique environmental setting of the Lake and the 

practices of those who are permitted to operate in the Lake.

Lopez, John A., Amoco, New Orleans Louisiana

REVIEW AND UPDATE OF ACTIVE GEOLOGIC FAULTING IN LAKE PONTCHARTRAIN.

Active geologic faults in Lake Pontchartrain have been previously described in 

1991.  These faults have apparent surface expression and strongly suggest that at 

least some of  these faults are currently active faults.  The en echelon fault 

system in the Lake  are the  southeastward continuation of the well documented and 

active  Baton Rouge - Denham Springs faults system in the Baton Rouge area.  

Documentation of geologic faulting in Lake Pontchartrain has continued since they 

were first described in 1991.   This includes: 1) GPS positioning of bridge 

offsets 2) acquisition of US Geological Survey high resolution seismic 3) more 

complete mapping of  all the faults in Lake Pontchartrain 4) new quantification 

Railroad and bridge offset at fault traces.

1) GPS positioning confirms the coincidence of bridge offset and projection of 

subsurface faults to the lake surface.  This also demonstrates a common strike 

orientation to both the surface and subsurface fault data.

2)The US Geological Survey high-resolution seismic data does show significant 

lateral changes at the projected position of the faults in eastern Lake 

Pontchartrain.  These changes are interpreted as  faults. However other 

interpretations may be plausible.  The high resolution seismic positioned parallel 

to the Causeway does not show any lateral change at all.  A fault is not seen on 

shallow seismic at the projected trace of the fault. near the northshore.  Two 

possible explanations are:  1) the projection of the subsurface fault to the 

bridge offset is coincidental and the fault is not active ,  2) the fault offset 

is too small to be detected by even the high resolution seismic.

3)  In 1995 a regional subsurface map of Lake Pontchartrain was released in a 

report from the Louisiana Dept. of Conservation.  This map used more complete 

seismic coverage than had been previously available and demonstrated two regional 

fault trends in Lake Pontchartrain.   The map  confirms the northwest-southeast 

trending faults which parallels the north shore.  These faults match the 

previously mapped trend which is the probable extension of the Baton Rouge-Denham 

Springs fault trend.   A second  fault system trending east-west  was also mapped 

in the southern half of Lake Pontchartrain.  These faults are more sinuous and are 

a  continuation of  the typical east-west fault trend seen throughout south 

Louisiana.  The east-west fault system converges with the northwest-southeast 

fault system in the southeast corner of Lake Pontchartrain.

4)  Simple visual observation and crude surveying has been used to attempt to 

quantify the apparent bridge offset by the faulting.  Recent observations suggests 

possibly higher rates of fault movement than previously suggested.  In particular 

the  Southern Railroad bridge has shown 2-3 inches offset at the southern fault 

position where the bridge was completely re-built in 1986 and 1987.  The northern 

fault trace shows similar new offset of the Southern railroad bridge.  This is 2-3 

times  higher than the  previous rate of fault movement suggested in 1991 by 

monitoring and observation at that time.  Most likely,  fault movement is episodic 

and the lower rates may be longer term average.  However it is possible that the 

fault movement is accelerating.

Lyons, S.E., Holy Cross School, New Orleans, LA.

PROJECT F.U.R. (FIGHT URBAN RUNOFF).

PROJECT F.U.R. (Fight Urban Runoff) is an ongoing environmental service project of 

students at Holy Cross School since 1990.  PROJECT F.U.R. raises public awareness 

of a used oil recycling program that benefits the Lake Pontchartrain Basin and the 

nation through energy conservation and the reduction of hazardous waste.  If used 

motor oil is not recycled and is discarded improperly, it can present a serious 

hazard to our environment.  Parish recycling centers, service stations and 

quick-change oil franchises are serving as collection centers.  The oil collected 

at these sites is reprocessed and prepared for future marketing.  With the 

donation of a "Crusher l" used motor oil filter compactor, Project F.U.R. members 

are able to collect used motor oil filters and recycle them.  Thus, the filter and 

the used oil inside are reclaimed and recycled, preventing them from posing a 

hazard to the Lake Pontchartrain Basin ecosystem.

Project F.U.R.'s speaker program focuses public attention on urban runoff and its 

effects on Lake Pontchartrain.  Flyers and brochures explain what residents can do 

to help stem this toxic tide.  Knowledge without action is sterile.  Other civic 

action projects by PROJECT F.U.R. include the "STENCIL-A-CANAL" project.  A 

network of high school students and teachers joins forces with civic organizations 

and local residents to stencil the logo, "Dump No Waste--Drains to Lake" on storm 

drain covers throughout the area.  This serves to remind residents that hazardous 

materials dumped in storm drains have a negative impact on the Lake Pontchartrain 

ecosystem.

PROJECT F.U.R. conducts water quality testing in the Lake Pontchartrain Basin at 

several sites.  Data is collected and evaluated for evidence of a decrease in 

runoff pollutants, allowing PROJECT F.U.R. students to fully participate in the 

scientific process.  In addition, weekly water testing of the Industrial Canal is 

contributing to a comparative study of drainage canals in New Orleans, currently 

under study by the Lake Pontchartrain Basin Foundation.

"Wetlands Ecology:  A Service-Learning Project" is the latest phase of Project 

F.U. R.  Student team leaders have learned wetlands ecology firsthand by 

participating in field camps at selected wetlands sites and by participating in 

volunteer projects to restore wetlands.  They have served as peer instructors to 

other students in environmental science classes on a series of field trips.

A healthy lake is a major recreational and economic asset to New Orleans and the 

surrounding parishes.  Achieving that goal through public education and civic 

action is the intent of PROJECT F.U.R.  The dimensions of the challenge are 

enormous, but with its effort supported by the Lake Pontchartrain Basin Foundation 

and the Louisiana Department of Environmental Quality, PROJECT F.U.R. has been 

very successful.  While rendering significant service to the community, these 

students are experiencing the scientific, social, and political components of 

environmental issues.

For their efforts PROJECT F.U.R. has been the subject of magazine and television 

coverage and has won local, state, and national awards, including the President's 

Environmental Youth Award for EPA Region 6 and Youth Conservationists of the Year 

for the Louisiana Wildlife Federation.

Manheim, Frank T.  U.S. Geological Survey, Woods Hole MA 02543, 

Charles .W. Holmes, U.S. Geological Survey, Lakewood CO, 80225, and 

S. Jeffress Williams, U.S. Geological Survey, Reston VA 22092

A NEW  GEOCHEMICAL DATA BASE FOR SEDIMENTS FROM THE LAKE PONTCHARTRAIN BASIN

As a part of a broad-based regional study of Lake Pontchartrain Basin (LPB) the 

U.S. Geological Survey is beginning compilation of a data base on chemical and 

other properties of bottom sediments. In addition to larger studies by 

university-based scientists,  the U.S. Army Corps of Engineers,  U.S. 

Environmental Protection Agency, USGS, and Louisiana state agencies, we will 

attempt to include all other available published and unpublished material.  We 

welcome cooperation in this effort and propose to make all data publicly available 

on CD ROM upon conclusion of the study.

Uniform methodologies , such as are employed in the larger studies of the Lake 

Pontchartrain region by the Louisiana Dept. of Environmental Quality, and by 

Flowers and Isphording, help assure internal comparability of data.  However, 

until recently,  the advisability of compiling  chemical data from heterogeneous 

historical sources has been questioned owing to differences in sampling and 

analytical methodology, degree of documentation, and quality.  Studies of 

heterogeneous historical sediment data from Massachusetts Bay have shown that 

special  batch screening   techniques are able to indentify anomalous values that 

result from systematic errors and other internal inconsistencies which  exceed 

limits for natural variability determined by well-controlled methods. This 

experience and the advantages of extending spatial and temporal data at relatively 

low cost, and developing better guidelines  for new data collection have 

encouraged planning of a more comprehensive data base. 

To facilitate cooperation,  we will make available to interested cooperators a 

detailed data dictionary. It accomodates most available chemical information on 

toxic components, both inorganic and organic, as well as major element data, 

sediment texture and other parameters. The data dictionary can be provided as a 

data entry template in floppy disk format. The format is  compatible with most 

commercial database and spreadsheet software for desktop computers. We attempt to 

document data from original sources in sufficient detail to minimize the necessity 

of users re-accessing such sources except where data other than sediments is sought.  

Materne, M.D., Natural Resources Conservation Service, Baton Rouge, LA, and 

Croughan, T.P. LA Agricultural Experiment Stations, Crowley, LA

BIOTECHNOLOGY DEVELOPMENTS IN PLANT MATERIALS FOR COASTAL RESTORATION.

The effectiveness of using plants to control erosion in upland situations has long 

been recognized.  Interest has more recently developed in applying this approach 

to erosion control along shorelines and in coastal wetlands.  On both economic and 

environmental grounds, plants offer an attractive adjunct to the structural 

approaches to erosion control typically utilized in these environments.  While 

physical structures predictably affect a relatively limited area, plants can 

spread to surrounding areas and beyond, both holding what remains while reclaiming 

lost ground.  Vegetative planting and seeding have been shown to retard the 

conversion of marsh to open water, to reduce the erosion of lake shorelines, canal 

banks, dunes or other marsh-water interfaces, and to promote the re-establishment 

of emergent wetland vegetation.  Plantings are often a low-cost marsh restoration 

and enhancement technique applicable in all coastal basins and across a wide range 

of habitat types, from freshwater swamps to saline marshes.

Despite the advantages that vegetation holds over many other physical approaches 

to coastal restoration, technical problems currently limit wider utilization of 

this biological approach to coastal wetland erosion control.  To date, much of the 

vegetative restoration work has been centered around plant species such as 

Spartina alterniflora (smooth cordgrass) and Scirpus californicus (California 

bulrush).  Both of these species establish quickly and spread vigorously by means 

of vegetative reproduction.  Both have demonstrated unique erosion control 

qualities and sediment accretion in areas of high wave energies and in areas of 

high suspended sediment loads.  Both species develop dense canopies, stem 

densities, and extensive root development.  However, like most coastal wetland 

species, both are poor seed producers and hand transplanting is the prevailing 

method for establishing.  Planting even small areas is costly, laborious, and has 

limited applications given the inaccessibility of much of Louisiana's coastal marshes.

Consequently, two areas that the Natural Resources Conservation Service's plant 

materials program is concentrating in are advancing biotechnology techniques for 

mass production and methods for large scale planting application.   Systems 

currently being developed for field testing are 1) economically mass production of 

plant materials designed to accommodate remote and extended planting sites 

(encapsulated plantlets); 2) genetic improvement of plants to extend their 

utility, range, and performance in varied wetland restoration application 

(laboratory-cultured cell lines); and 3) mechanical methods for establishing 

extended planting sites (hydro-sodding).

Meffert, Douglas J., and  Good, Bill Ph. D., Coastal Restoration Division, 

Louisiana Department of Natural Resources, Baton Rouge, LA 70804-9396

ECOSYSTEM MANAGEMENT IN THE BRETON SOUND ESTUARY

The Breton Sound Estuary in Louisiana, an area 280,287 square km in extent, 

annually loses an average of 408 square km of marsh.  This system has suffered a 

series of major anthropogenic impacts including the completion of flood-control 

levees along the Mississippi River in the 1920's, the Mississippi River Gulf 

Outlet (a major navigation canal) in 1963, and a labyrinth of smaller canal for 

oil extraction primarily from 1950 through 1980.  Thus, the estuary was decoupled 

from alluvial water sediment and nutrients; then extensively connected to marine 

processes.  The most immediate impact of these actions was a landward shift in 

salinity. Secondary impacts included land loss, habitat degradation, loss of 

biodiversity, and an inland shift in oyster production.  Various attempts to 

ameliorate the direct and indirect consequences of these hydrologic alterations 

include several freshwater diversion projects constructed by different entities 

for various management objectives.  However, environmental administration of the 

area has been evolving in the direction of ecosystem-level management.  The 

authors discuss the remaining hurdles that must be overcome in the final phase 

towards ecosystem management of this real-world case study.  Both the scientific 

and policy-related challenges and opportunities associated with such a strategy 

will be discussed.

Melancon, George E., Louisiana Department of Wildlife and Fisheries, Ferriday, La.; 

Chabreck, Robert H., School of Forestry, Wildlife, and Fisheries, Louisiana State 

University Agricultural Center, Baton Rouge, La. 70803

WINTERING LESSER SCAUP ON LAKE PONTCHARTRAIN AND THEIR RELATIONSHIP TO MOLLUSK ABUNDANCE

Lake Pontchartrain is an important wintering area of Lesser Scaup (Aythya affinis) 

in southeastern Louisiana.  This study was conducted to evaluate current Lesser 

Scaup use of the lake and the relationship between Lesser Scaup concentrations on 

the lake and the abundance of mollusks.  Biweekly surveys were made on the lake 

from October 1994 through March 1995.  Lesser Scaup were first observed on 21 

October 1994.  Peak winter populations were present on 23 January 1995.  Lesser 

Scaup were not observed on Lake Pontchartrain after March 8,1995.

Aerial surveys were conducted in December, January, and February to estimate 

Lesser Scaup numbers on the lake and concentration levels in different areas of 

the lake.  Peak winter populations were estimated to be 250,762 birds on 17 

January 1995.  Bottom samples were collected in areas of Lake Pontchartrain where 

scaup abundance was classified as high, medium, low, and absent, and mollusks 

present were recorded by species, size, and abundance.  Areas with high Lesser 

Scaup densities contained a greater volume of Rangia cuneata in the <1 cm size 

class than the areas of low Lesser Scaup densities.  Bottom samples in areas with 

an absence of Lesser Scaup had greater volume of Rangia cuneata in the 1-3 cm size 

class.

A strong positive relationship occurred between distance from the shore and Lesser 

Scaup densities.  No relationship was found between distance from the shore and 

volume of Rangia cuneata in any of the three size classes.  Lesser Scaup 

apparently are unable to use the medium or larger-sized Rangia cuneata as a food 

source and thus concentrate in areas of Lake Pontchartrain were there are greater 

amounts of the smaller Rangia cuneata.

Miller, M. S., Department of Biological Sciences, Southeastern Louisiana 

University, Hammond LA

A CRITICAL EVALUATION OF THE WETLANDS VALUE ASSESSMENT.

The Wetland Value Assessment (WVA) is a quantitative habitat-based assessment 

methodology developed for the use in prioritizing project proposals submitted for 

funding under the Coastal Wetlands Planning, Protection, and Restoration Act 

(CWPPRA) of 1990 (Mitchell, et. al. 1990).  The WVA uses only existing or readily 

obtainable data. The WVA ranking procedure quantifies the feasibility and quality 

of proposed wetland restoration projects and is measured in Average Annual Habitat 

Units (AAHU's).  The WVA, developed by an Environmental Work Group assembled under 

the Planning and Evaluation Subcommittee of the CWPPRA Technical Committee, is a 

modification of the Habitat Evaluation Procedures (HEP) developed by the U.S. Fish 

and Wildlife Service (U.S. Fish and Wildlife Service 1980) (Mitchell, et. al. 1990).  

HEP is used throughout the country by various Federal and State agencies in 

evaluating the impact of development projects on fish and wildlife resources.  The 

WVA operates under the assumption that optimal conditions for fish and wildlife 

habitat  can be characterized, and that existing or predicted conditions can be 

compared to that optimum to provide an index of habitat quality (Mitchell, et. al. 

1990).  There are six variables that have been chosen to characterize four wetland 

types, and these variables range in value from 0.1-1.  A variable with a value of 

0.1 would be considered to be of the lowest habitat value possible, while a 

variable with a value of 1 would be the representative of the best possible 

habitat value.  The six variables used in the WVA include: V1-- The percentage of 

wetland area covered by emergent vegetation ( ( 10% canopy cover ), V2-- Percent 

of open water area dominated    ( > 50% canopy cover ) by aquatic vegetation, 

V3--Marsh edge and interspersion, V4--Percent of open water area ( 1.5 feet deep, 

in relation to marsh surface, V5--Mean high salinity during the growing season 

(March through November), V6--Aquatic organism access.  When these variables are 

ranked in a specific WVA, they are then run through the current formula and a 

single Habitat Suitability Index (HSI) is the result.  The HSI is then transformed 

into it's relative number of AAHU's and weighed against other project AAHU's.  The 

projects with the highest rankings for the year are then considered for funding in 

accordance with CWPPRA.

Two different Wetland Value Assessment (WVA) models were analyzed using the 

statistical package SYSTAT.  The first model is the current WVA used by the State 

of LA to determine the value of a wetland area.  The second is a simpler, 

arithmetic formula.  After completing a Pearson Correlation Matrix for the data 

set it was found that the current formula was very highly correlated (0.98) with 

the derived formula, indicating that the formulas outputs were very similar.  It 

was also discovered that V1 (emergent Marsh) was highly correlated with both 

models, suggesting that it was the driving force behind the models.

Multiple regressions were performed, with high degrees of predictive abilities for 

both models.  The driving force behind the regressions was also V1, with V3, V4, 

and V5 only contributing little to the current model.  When the same regression 

was done on the arithmetic model all variables took on a more even importance 

(except V1, which was still the most important).  After eliminating certain 

variables from the models, regressions were run again.  These runs gave lessened 

predictive abilities for both models (except when only V5 was removed).  This 

suggests that all variables contribute some importance except variable 5.

Loading of variables onto certain "factors" was the next step in the analysis.  

Variables 1 and 3 loaded on a factor which could be considered the emergent marsh 

factor.  Variables 5 and 6 loaded on a factor which could be designated salinity.  

Variables 2 and 4 loaded on the aquatic vegetation factor.  Both model outcomes 

(HSI) loaded heavily on to factor 1 (the marsh factor), which is precisely what 

CWPPRA was designed to protect and restore.

Pedalino, Francesca A. and Poirrier, Michael A., Department of Biological 

Sciences, University of New Orleans

THE STATUS OF BENTHIC INVERTEBRATE POPULATIONS IN SOUTHERN LAKE PONTCHARTRAIN.

A non-mixing, bottom layer of more saline water occurs in southern Lake 

Pontchartrain due to saltwater intrusion through the Inner Harbor Navigation Canal.  

Organic material from urban runoff and algal growth accumulates in this bottom 

layer and reduces dissolved oxygen concentrations which causes stress on benthic 

organisms.  Areas of the bottom which lack large invertebrates have been termed 

"Dead Zones".  Conditions in Lake Pontchartrain during the summer of 1995 were 

favorable for the development of saline bottom waters with a high concentration of 

organic material.  Heavy rainfall in April and early May of 1995 introduced plant 

nutrients and organic material.  After this rainfall and associated flooding, a 

period of over twenty days without rainfall occurred.  This dry period allowed the 

movement of saline bottom water into the estuary.  Nutrient rich Mississippi River 

water entered Lake Pontchartrain through the Bonnet Carre Spillway during June and 

July of 1995, and intense blooms of the blue-green algae and associated fish kills 

occurred during July of 1995.

			    

Sites in southern Lake Pontchartrain were sampled on November 19, 1995 to 

determine the condition of bottom waters and the status of benthic invertebrate 

populations.  Salinity and dissolved oxygen measurements were made and benthic 

invertebrates sampled at nine stations along two transects which ran from the 

mouth of the Inner Harbor Navigation Canal west to the Lake Pontchartrain Causeway 

at 2.5 and 5.0 miles from shore.

Although strong north winds which can mix south shore waters occurred before 

sampling, salinity stratification and low bottom dissolved oxygen concentrations 

were present.  Past studies of benthic invertebrate populations in the same study 

area found communities indicative of stressful conditions near the Inner Harbor 

Navigation Canal and a transition to communities indicative of normal conditions 

occurring with distance from the canal.  In contrast, November 1995 samples 

indicated stressful conditions at all sites on both transects.  The number of 

mollusks, including the clam Rangia cuneata and the snails Texadina sphinctosoma 

and Probythinella louisianae was low at all sites.  The benthic invertebrate 

community was dominated by oligochaetes and polychaetes which are known to 

tolerate stress.  The presence of few mollusks and numerous annelids at all sites 

indicates that adverse environmental conditions occurred throughout the study area.   

Penland, S., Louisiana State University, Baton Rouge, LA; 

Wayne, L., Louisiana State University, Baton Rouge, LA; 

Britsch, D., U.S. Army Corps of Engineers, New Orleans, LA; and 

Williams, S.J., U.S. Geological Survey, Reston, VA,

COASTAL LAND LOSS RATES, FORMS, AND PROCESSES IN THE PONTCHARTRAIN BASIN.

The Pontchartrain Basin in this coastal land loss study extended from Lake 

Maurepas through Lake Pontchartrain to Lake Borgne and includes the areas north of 

the MRGO navigation channel.  Utilizing the USACE-NOD coastal land loss GIS 

database, the authors used a subset of this information to quantify the rates, 

forms, and processes of loss in the Pontchartrain Basin.

The rate of coastal land loss in the Pontchartrain Basin has averaged -1.97mi2yr-1 

between the 1930's and 1990's.  The rates of loss have accelerated from 1.43 

mi2yr-1 in 1930's/1950's to -3.07 mi2yr-1 in 1950's/1970's.  Since these time 

periods, the rate of land loss has decreased from -1.97 mi2yr-1 in 1970's/1980's 

to -1.41 mi2yr-1 in the 1980's/1990's.  Coastal land loss occurs throughout the 

basin, however, the eastern basin has greater loss than the western basin.

To further quantify coastal land loss, a geomorphic classification was developed 

for GIS analysis.  Coastal land loss has two basic forms, shoreline loss and 

interior loss.  Shoreline describes areas of loss that occur relative to existing 

water bodies.  Interior describes areas of loss that occur independent of existing 

water bodies.  The next level of the hierarchy addresses the water body type most 

closely related to loss.  For shoreline areas, this level depicts the type of 

water body physically related to the loss.  Four classes of shoreline loss were 

established:

	1)   gulf - the outer shoreline facing the Gulf of Mexico,

	2)   bay - semi-enclosed water body with direct contact to the Gulf of 

		Mexico, 

	3)   lake - enclosed or semi-enclosed water body with no direct contact to 

		the Gulf of Mexico, and

	4)   channel - linear water body that commonly connects other water bodies.

For interior areas, this level of the classification depicts the water body type 

that is most similar new interior loss.  Two interior classes were established:

	1)   pond - enclosed or semi-enclosed water body with minor connections to 

		the existing drainage network, and 

	2)   channel - narrow, linear water body.

Once the forms of loss were delineated and mapped, a process classification was 

developed to quantify cause.  The first level of the classification hierarchy 

addresses the basic processes of land loss.  For purposes of this classification 

scheme, the term land is defined as all subaerial materials including surface 

vegetation, sediments, and organic soils.  Three primary land loss processes were 

identified:

	1)   erosion - mechanical removal and transport of land by water action,

	2)   submergence - increase of water level relative to ground surface 

		elevation, and 

	3)   direct removal - physical removal of land by actions other than water.

A fourth category, undetermined, is included for those areas to which no 

assignment can be made.

The second level of the process classification scheme identifies the primary 

physical actions that are associated with each loss process.  This level of the 

classification includes both natural and cultural actions.

The action of erosion include:

	1)	scour - mechanical removal of land by water, and 

	2)	transport - suspension and conveyance of land by water.

The actions of submergence include:

	1)	flooding - short-term increase in water level,

	2)	substrate collapse - reduction in substrate thickness, and 

	3)	subsidence - reduction in land surface elevation.

The actions of direct removal include:

	1)   excavation - extraction and transport of land to another location, and 

	2)   burning - oxidation of the organic component of land.

At the third level of the process classification scheme, issues of cause emerge.  

This level identifies the natural and cultural catalysts to the physical actions.  

Natural catalysts include phenomena such as wind, loss of vegetation, high water, 

loading, and faulting.  Cultural catalysts include human activities such as 

dredging of navigation channels, building of impoundments, resource extraction, 

excavation of ponds, and fires.

The fourth level of the process classification identities the factors known to 

stimulate natural and cultural land loss catalysts.  This is a diverse category of 

information which includes natural and cultural events, activities, and structures.  

Factors included at this level of the classification scheme include storms, 

herbivory, sediment transport, recreation, agriculture, commerce, levees, and 

engineered coastal preservation/restoration structures.

In the Pontchartrain Basin, natural erosion and submergence account for a small 

percent of the coastal land loss problem.  A greater percentage is related to 

man's activities such as canals, highways, failed land reclamation, borrow pits, 

and altered hydrology.  This paper presents the results of the GIS land loss 

analysis.

Poirrier, Michael A., Department of Biological Sciences, University of New Orleans

THE BIG STINK OF 1995:  OBSERVATIONS ON ALGAL BLOOMS, FISH KILLS AND GRASSBED DECLINE.

Intense blue-green algal blooms fish kills, grassbed loss and dead zone expansion 

occurred in Lake Pontchartrain during the summer of 1995.  Unusual environmental 

conditions were associated with the algal blooms, and related events.  Runoff from 

heavy rainfall in April and early May, and Mississippi River water which entered 

through the Bonnet Carre Spillway in June and July lowered salinity and introduced 

plant nutrients.  In addition, the weather during the summer of 1995 was hotter 

and dryer than normal.

Blooms of the blue-green alga, Anabaena occurred from late June through mid July 

1995.  Algal distribution and density were difficult to quantify because algae 

accumulated near the surface and moved with wind.  At times it was present 

throughout the estuary, and at other times it was concentrated on the north or 

south shore depending upon wind direction.  Thick accumulations of algae near the 

shore and in embayments resembled concentrated pea soup.

Fish kills occurred in Bayou St. John and the West End Marinas during July.  They 

were caused by the accumulation of decaying blue-green algae in areas where fish 

could not move away.  A Myriophyllum grassbed which was located near the mouth of 

Bayou St. John died due to overgrowth by filamentous algae and shading by Anabaena.  

The decaying vegetation contributed to the bayou fish kill.  Shading by Anabaena, 

the growth of epiphytes and changes in water chemistry adversely affect 

Vallisneria grassbeds in other areas.

The blue-green algal blooms and associated events are indicative of high levels of 

plant nutrients.  Runoff from record rainfall in May and the flow of Mississippi 

River water through the Bonnet Carre Spillway during mid-summer were sources of 

nutrients.  The hot, static weather with little rainfall during June was probably 

another major contributor to the bloom.  Algae and nutrients were not flushed out 

of the estuary by freshwater discharge, or wind generated water level changes, but 

were retained in clear, warm, low-salinity water for an unusually long period.  

Water exchange associated with tropical storm Erin in early August flushed out the 

algae, increased salinity and abruptly ended this eutrophic episode.

Preslan, J.E., Adams, S., Bollinger, J., George, W.J. and Anderson, M.B. Tulane 

University Medical School, 1430 Tulane Ave., New Orleans, LA 70112.  

GENERAL WATER QUALITY AND SEDIMENT CONDITIONS IN THE LABRANCHE WETLANDS ASSESSED 

USING IN SITU  TESTING AND SEDIMENT CORE EVALUATIONS

Bayou Trepagnier, located within the LaBranche wetlands, is a waterway adjacent to 

the Shell Oil Manufacturing Complex in Norco, Louisiana which has sediments that 

have been contaminated with petroleum residues since the mid 1950's.  Recent 

studies conducted by our laboratory have identified the presence of polyaromatic 

hydrocarbons and elevated levels of lead and chromium as significant contaminants 

in the sediments.  Between February 1994 and December 1995, nitrate, nitrite, 

ammonia, phosphate and silicate levels in the water column have been monitored 

periodically. Nutrient and metal fluxes as well as oxygen profiles were assessed 

at a heavily contaminated site (Marker 105) in Bayou Trepagnier and at a control 

site in Bayou Traverse during March, 1994 and September, 1995.  The studies were 

conducted using 6 foot long pipes driven into the floor of the Bayou to isolate a 

segment of the sediment and the overlying water column.  Changes in water quality 

were observed under conditions of reduced water flow and reduced exchange of 

oxygen with the air.  The differences observed between the two time periods and 

between the two sampling sites may reflect differences in seasonal conditions, 

site contamination, and the change in the pattern of discharge from manufacturing 

plant activities into the Bayou.  Density, organic content, and oxygen demand of 

the sediments from various locations within the wetlands were also measured.  

Supported by D.O.E.

Sabate', R.W., Stiffey, A.V., and Dewailly, E.L., Lumitox Gulf L. C., New Orleans, LA

TESTING TOXICITY OF LAKE PONTCHARTRAIN WATERS WITH A BIOLUMINESCENT ORGANISM

Water samples taken in the Spring of 1994 from nine stations near the southeastern 

shore of Lake Pontchartrain for Lake Pontchartrain Basin Foundation by the New 

Orleans Power Squadron were shared with a private toxicity testing laboratory.  

These samples were tested by the Foundation only for coliform bacteria.  They were 

tested on a contemporary basis by the laboratory for acute total toxicity with a 

microscopic, naturally bioluminescent marine dinoflagellate alga, Pyrocystis 

lunula.  When exposed in the dark to stress, such as stirring, this organism emits 

a strong, pale-green light, or bioluminescence (the sailor's "phosphorescence").  

Light values are measured, one minute per sample replicate (usually five), by a 

hand-held, portable toxicity tester.  Laboratory incubation time is four hours; 

range-finder tests in the field take only one hour.  The presence of toxicants 

measurably reduces the amount of light emitted, as compared to a non-toxic control.  

This relative light reduction, in percentage terms, is called "bioluminescence 

inhibition," or BI.  Variation among negative controls and replicate test 

samples - and among positive controls (sodium lauryl sulphate) from day to day - 

typically is less than 10%.  The test organism is very sensitive to strong toxins.  

For example, concentrations in ppt of some household pesticides and herbicides 

cause total light extinction.  Empirically, BI<10 is regarded as non-toxic, BI>50 

gives rise to concern, and 10<BI<50 is a range of low to mild toxicity.  EPA 

permits discharging oil-well drilling fluids with BI<63 directly into the sea.  

Maximum BI observed in the Lake samples was 45, mildly toxic.  The easternmost 

samples, off Lincoln Beach, consistently were the least toxic:  BI = 10 to 23.  

Some BI values correlate with coliform counts, while most seem completely 

independent.  There being no scientific basis for the test organism to be 

sensitive directly to coliform bacteria, it must be sensitive to contaminants 

carried into the Lake from some sources along with the bacteria.  Repeat testing 

of the same samples eleven days later generated a significantly lower BI for eight 

of the nine stations (average 27% lower overall), suggesting natural remediation.  

This implies that Lake Pontchartrain will cleanse itself quickly of contaminants 

if their sources are eliminated.

Shaffer, G., Greene, M., Llewellyn, D., Myers, R., and Forder, D., Department of 

Biological Sciences, Southeastern Louisiana University, Hammond, LA

SWAMP RESTORATION IN LOUISIANA: AMELIORATION OF MULTIPLE STRESSORS - 

IS IT WORTH THE COST?

In the early 1900s, old-growth baldcypress (Taxodium distichum) was completely 

logged out of most of Louisiana's swamps.  Natural regeneration of swamp was 

limited and many areas converted to marsh or open water.  This effort was 

conducted to isolate the major factors prohibiting cypress regeneration.  

Specifically, hundreds of baldcypress seedlings were planted in several factorial 

treatment arrangements that included nutrient augmentation (fertilized vs. 

unfertilized), management of entangling vegetation (managed vs. unmanaged), 

herbivore protection (Tubex( tree shelters, PVC sleeves, Tanglefoot), elevation 

(raised vs. not raised), substrate type (natural, topsoil, sand), silvicultural 

practices (clear cut, select cut, uncut), and salinity inundations (0 ppt, 5 ppt, 

10 ppt).  Nutrient augmentation nearly doubled growth in an estuarine location, 

but decreased growth in a riparian location.  Seedlings that were managed grew 

nearly two times greater in diameter than unmanaged seedlings.  However, seedlings 

that were unmanaged grew nearly two times greater in height than managed 

seedlings.  Relatively inexpensive, recyclable, PVC sleeves were more effective at 

prohibiting herbivory than Tubex( Tree Shelters; unprotected seedlings experienced 

100% mortality.  Initial restoration efforts should be concentrated in raised 

areas, such as natural levees.  Successful coppicing, of cypress but not tupelo 

(Nyssa aquatica), is occurring in clear- and select-cut areas.  Cypress can 

tolerate in situ salinity pulses of up to 10 ppt.  In all, these studies indicate 

that biotic factors are primarily responsible for the lack of cypress regeneration 

in Louisiana, not the prevalent, but largely untested, hypothesis of salt water 

intrusion.  Moreover, it is likely that, with a combination of management 

techniques, it is possible to restore swamp habitat in this area.  Though labor 

intensive in the short run (i.e., first few years), once established these trees 

may survive for many centuries.

Signell, R.P., U.S. Geological Survey, Woods Hole, MA, List, J.H., USGS, Woods 

Hole, MA and Stumpf, R.P., USGS, St. Petersburg, FL

MODELING STORM-DRIVEN CIRCULATION IN LAKE PONTCHARTRAIN           

The U.S. Geological Survey is conducting a study of storm-driven sediment 

resuspension and transport in Lake Pontchartrain.  Central to understanding the 

transport of sediment during storm events is determining the lake circulation 

patterns due to remote and local forcing.   Chuang and Swenson (Journal of 

Geophysical Research, 1981) and Swenson and Chuang (Estuary, Coastal and Shelf 

Science, 1983) showed that non-tidal water-level variations in Lake Borgne 

dominate the flux of water through Rigolets and Chef Menteur passes and thus play 

a large role in flushing of the lake.   In addition to remote forcing, circulation 

is driven by the winds over the lake.   Some aspects of the depth-averaged 

circulation response to local wind were described in a modeling study by Hamilton 

et al (Journal of the Waterway, Port, Coastal and Ocean Division, ASCE, 1982).  

This study showed that transport in shallow water around the periphery of the lake 

was downwind, whereas transport in the deeper central region of the lake was upwind. 

We use a three-dimensional numerical model to understand the relative 

contributions of remotely-driven and locally-driven currents on the circulation in 

Lake Pontchartrain.   Results of the modeling effort indicate that remote forcing 

dominates the circulation near the passes in the eastern end of the lake, while 

local forcing dominates water movement in the western end.  Locally-driven 

circulation responds to the magnitude of the wind, while the remotely-driven 

circulation responds to changes in Lake Borgne (often related to changes in the 

alongshore component of wind).   During typical storms with winds from the 

north-northeast or the south-southeast, currents along the south coast near New 

Orleans generally transport material westward, while material in the central 

region moves against the wind.   When periods of sustained winds are followed by a 

drop in coastal sea level, a large amount of suspended sediment can be flushed 

from the Lake.  Remote sensing images of turbidity are used to document the 

distribution of suspended sediments during strong wind events.

Soudamini Mishra , Flowers, G. C., and Kohl, B., Geology Department, Tulane 

University, New Orleans, La., 70118.

BENTHIC FORAMINIFERA AND HEAVY METALS IN THE LAKE PONTCHARTRAIN

Lake Pontchartrain is the largest brackish water body in Louisiana.  The lake's 

ecosystem is threatened by urban runoff from the New Orleans metropolitan area and 

agricultural runoff from surrounding parishes.  Benthic organisms are a good 

indicator of pollution because they have low motility, as well as high sensitivity 

to changes in water quality caused by pollution. This study focuses on the use of 

benthic foraminifera in Lake Pontchartrain to monitor the impact of heavy metal 

pollution on benthic communities.  Bottom sediments were collected from stations 

in the vicinity of outfall canals along the south shore of Lake Pontchartrain.  A 

split of each sample was used to determine the heavy metal content using ICPAES 

and particle size distribution using the sieve/hydrometer method.  Benthic 

foraminifera were concentrated from the other split by wet sieving.  Foraminifera 

samples were dissolved and analyzed for As, Al, Cr, Cu, Pb, Zn, Ba, Mn, Fe, Ni, 

and Co contents.  As, Pb, Ba, and Co levels were found to be elevated in bottom 

sediments taken in the vicinity of outfall canals.  These metal concentrations are 

higher than average values for the lake taken as a whole and average shale values.  

Average lake sediment values for As were not available for comparison.  Benthic 

foraminifera found in the lake sediments are dominated by agglutinated varieties; 

a total of 10 species of foraminifera were found in bottom sediment samples.  The 

assemblage consists of (in order of abundance) Ammobaculites subcatelanulatus, 

Ammoscalaria? dilatatus, Ammobaculites exiguus, Ammotium directus, Miliammina 

fusca, Ammonia beccarii, Arenoparella mexicana, Ammoastuta inepta, Elphidium 

gunteri salsum and Ammontium salsum.  Comparison of the concentration of Cu, Cr, 

Pb, and Zn in foraminifera tests and sediments suggests that Cu and Zn may be 

preferentially absorbed in foraminiferal tests relative to Pb and Cr.  Cr in 

foraminifera tests is a little higher than in the sediment, whereas the 

concentration of Pb is approximately equal to the sediment concentration.  It is 

not known whether or not this conclusion holds in general given the relatively 

small area where samples were collected.

Steiner, S.J. and Grymes, J.M., III, LSU Southern Regional Climate Center, 

Baton Rouge, LA.  

LAKE PONTCHARTRAIN'S METEOROLOGICAL MONITORING NETWORK.

Considerable energy and resources have been and will be invested into various 

environmental assessments of the Lake Pontchartrain Basin.  In many cases, these 

research endeavors require meteorological and climatological information to 

adequately describe the entire environmental characteristics of the nation's fifth 

largest natural lake (excluding the Great Lakes).  In past years, the availability 

of detailed, representative long-term weather/climate data has been restricted to 

observations taken at New Orleans International (Moisant) and Lakefront Airports.  

Unfortunately, as many researchers are well-aware, these two sites fall short of 

providing a complete picture of the variability of the basin's meteorological 

characteristics.

Unbeknownst to most of us, the National Weather Service has maintained a series of 

four data-collection stations around Lake Pontchartrain for more than fifteen 

years.  These automated platforms were installed to provide NWS personnel with 

supplemental real-time information regarding meteorological and hydrological 

conditions impacting the lake, particularly during unusual or severe weather.  

Currently, stations are located near the Rigolets at Fort Pike ('East Lake'), at 

the foot of the Causeway ('North Shore'), near Frenier ('West Lake') and along the 

Causeway near the center of the lake ('Mid Lake').

As the network was created for real-time assessment, little consideration was 

given to its potential for research services and support.  Thus, no provisions 

were established by the NWS for the long-term archival of these data.  Recognizing 

these data as a unique resource for regional assessment of meteorological, 

climatological and hydrological characteristics of the Pontchartrain Basin, LSU's 

Southern Regional Climate Center (SRCC) implemented a data collection and storage 

scheme based on data delivered via INTERNET feeds.  The SRCC's Pontchartrain 

archive of hourly data currently extends from January 1993 to the present, with a 

valid-report frequency of approximately 90% for the variables reported by the 

platforms.

Variables recorded on an hourly basis by all four automated stations include air 

and water temperatures, lake level (relative water level), precipitation, and wind 

speed and direction.  In addition, the 'North Shore' site reports dewpoint 

temperature and visibility.   The regional monitoring of meteorological 

characteristics can be further augmented by the inclusion of hourly observations 

from the manned weather offices Lakefront Airport as well as data from nearby 

Moisant Airport and the NWS Regional Forecast Office in Slidell.  Middle- and 

upper-atmospheric data are also recorded twice each day at Slidell's NWS site.

Already the SRCC has used these data to provide support services and 

climatological interpretations of basin characteristics for the US Army Corps of 

Engineers and the USGS.  The purpose for this presentation is to notify other 

environmental researchers that the SRCC serves as a resource for their respective 

studies as well.  More importantly, our goal is to extend beyond the limitations 

of a data-provision center and to assist the Pontchartrain research community by 

providing climatological expertise for the evaluation of the basin.

Steller, Diana Lee, Reptile Defense Network, Baton Rouge, La.  

RESTORING AN URBAN ESTUARY WITH CHRISTMAS TREES AND FLOWERS:  MAKING A HOME FIT 

FOR THE BIRDS

Coastal and shoreline erosion are reducing the viability of our estuarine 

heritage.  The seaward shoreline relentlessly retreats while interior marshes 

deteriorate and emergent vegetation gives way to open water.  The project area is 

located in the eastern portion of the Mississippi Deltaic Plain.  Only 16 miles 

east of the New Orleans Central Business District, the 20,000+ acre area borders 

Lakes Pontchartrain and Borgne and contains fresh, intermediate, and brackish 

marshes, bottomland hardwoods, barrier island live oak hammocks, and submersed 

aquatics.  Home to over 50,000 waterfowl annually, the area contains a national 

register property, 19 archeological sites, a bald eagle nest, four state-ranked 

plants and animals including american alligator, three state-ranked natural 

communities, wading bird rookeries, and abundant fisheries resources.  The story 

of the Bayou Sauvage Refuge is similar to that of many areas throughout the 

Pontchartrain Basin, Louisiana and the entire Gulf Coast.  Over half of the refuge 

has been impounded and impacted by hurricane protection levees, three major roads 

including an Interstate and two state highways, one oil and gas pipeline canal, 

two railroads and one major waterway (GIWW) leaving a little over half of the area 

free access to Lake Pontchartrain.  In addition to these man-induced changes, 

subsidence rates average one foot per century and shoreline erosion rates have 

been estimated at 4.8 - 11 ft/yr on Lake Borgne and 10.2 to 37 ft/yr along Lake 

Pontchartrain (CEI 1984).  Thus, natural processes combined with human 

intervention have led to the loss of 117 ac/yr between 1956 and 1988 (USFWS 1994).  

Large interior ponds developed within and outside of the impounded/managed areas.  

Over the last three decades coastal and shoreline erosion processes have breached 

stable shorelines and caused massive deterioration of interior marshes.  The 

resources at risk are the wetland marsh and submersed aquatic grassbed habitats 

and the recreation, fishery, waterfowl and wildlife they support.  This project, 

funded by the Gulf of Mexico Program, uses wave-damping fences built in a 

checkerboard pattern and natural occurring emergent and aquatic plantings to 

reduce fetch and wave action, encourage sedimentation, build habitat, and protect 

adjacent shorelines.  The techniques involved are new and are combined in a unique 

way to maximize their success in this environment.

The overall objective of the project is to reduce coastal erosion and increase 

marsh and grassbed habitats.  Subsidiary objectives are to reduce fetch, dampen 

waves and seiche, stabilize sediment, encourage sediment accretion, increase 

submersed aquatic and emergent vegetation growth, and increase the land to open 

water ration.  Specific objectives include building 3,000 ft of wave-damping fence 

structures in an open checkerboard pattern in shallow open water ponds to reduce 

fetch, damp waves and encourage local sediment accretion, stabilizing fragile 

bordering shorelines and marshes surrounding the open water ponds by reducing 

fetch and wave action, documenting sediment accretion and shoreline movement by 

monthly monitoring of sediment elevation relative to fixed posts and shoreline 

markers, and planting 5,000 submersed aquatics and emergent plants adjacent to 

wave-damping fences (e.g. Vallisneria americana (celery grass), Najas 

guadalupensis (southern naiad), Iris giganticaerulea (large blue iris), Crinum 

americanum (swamp lily), and Scirpus californicus (giant bulrush).  A subsidiary 

objective is to expand public awareness of resource problems and solutions by 

volunteer participation in construction and planting of the project.

The first study area is an impounded fresh to intermediate pond and a brackish 

estuarine pond.  Both have experienced drastic increases in their pond areas and 

reduction in their vegetated areas.  The site 1 interior pond is about a foot 

deep, over a mile wide and adjacent to a pipeline canal.  The large fetch to depth 

ration causes high wave action and constant resuspension of the fine organic 

bottom sediments.  Breaches in the pipeline canal cause water flow into the canal 

and overall loss of sediment from the pond into the deeper (8 ft) canal.  Unstable 

sediment conditions and high turbidity are factors in the lack of any submersed 

aquatics in the pond.  The project criss-crosses areas in the pond near canal 

breaches with a checkerboard pattern of treated wood Christmas tree fences.  

Standing water vegetation has been planted adjacent to and within the completed 

fences.  Similar wave-damping fences built in the area have been shown to reduce 

wave action.  The criss-cross design of earthen levees has been shown to be very 

effective in reducing fetch and wave action.

The second study area is an estuarine pond about a 1/2 mile wide and only a few 

inches deep.  It is bordered by a fragile marsh covered island on the lakefront.  

This marsh has breached and currently high waters from Lake Pontchartrain are 

further deteriorating the interior pond.  Wave-damping fences in a criss-cross 

pattern have been built surrounding the remaining bordering marsh and across the 

ponds in order to bolster and expand the shoreline as well as to reduce fetch and 

wave action in the pond.  Submersed aquatics will be planted in the open water, as 

well as marshhay cordgrass in the intertidal zone.  Both of these sites will be 

monitored monthly after construction and planting of the project.  Parameters to 

be monitored include percent survival, percent over and average height of 

plantings, sediment accretion, and shoreline retreat or advance.

Tao, Q., Louisiana State University, Baton Rouge, LA; 

Zganjar, C., Louisiana State University, Baton Rouge, LA; 

Westphal, K.A., Louisiana State University, Baton Rouge, LA; 

Penland, S., Louisiana State University, Baton Rouge, LA; 

Mathies, L., U.S. Army Corps of Engineers, New Orleans, LA; 

Nord, B., U.S. Army Corps of Engineers, New Orleans, LA; and 

Gunn, R., U.S. Army Corps of Engineers, New Orleans, LA,

THE BENEFICIAL USE OF DREDGED MATERIAL AT THE MISSISSIPPI RIVER GULF OUTLET - 

JETTIES BETWEEN 1985 AND 1995.

The Mississippi River Gulf Outlet (MRGO) navigation channel is located in 

southeast Louisiana.  The U.S. Army Corps of Engineers-New Orleans District 

(USACE-NOD) periodically dredges this navigation channel and beneficially uses 

this material to create, enhance, and restore the surrounding coastal wetlands.  

The USACE-NOD in cooperation with Louisiana State University-Coastal Studies 

Institute documents the creation and enhancement of new coastal land using dredge 

material along the MRGO through the Beneficial Use Monitoring Program (BUMP).

The total area of the MRGO study area  in 1985 was 2603.58 acres.  Natural 

processes accounted for 2283.65 acres or 88 percent of the total area.  Man-made 

processes related to beneficial use of dredge material accounted for 319.93 acres 

or 12 percent of the total area.  The total area of the MRGO study area  in 1995 

was 2473.87 acres.  Natural processes accounted for 2056.73 acres or 83 percent of 

the total area.  Man-made processes related to the beneficial use of dredge 

material accounted for 417.14 acres or 17 percent of the total area (Table 1).  

The MRGO study area decreased by -129.71 acres between 1985 and 1995.  Natural 

processes were responsible for -226.92 acres of decrease and the beneficial use of 

dredge material was responsible for -97.21 acres of increase.

Natural processes are responsible for eroding salt marsh.  Beneficial use of 

dredged material appears to be effective in creating shrub/scrub, bare land, and 

salt marsh.  The field surveys indicate the correct stacking heights are optimal 

for creating salt marsh and to a lesser extent shrub/scrub.  The optimal elevation 

for marsh creation appears to be less than +2 feet MSL.  At the MRGO - Jetty study 

area, the beneficial use of dredged material created 122.51 acres of new habitat 

between 1985 and 1995.  This total includes: 54.99 acres of salt marsh, 33.64 

acres of shrub/scrub, 19.04 acres of bare land, and 14.84 acres of beach.  Within 

the MRGO - Jetty study area, the beneficial use of dredged material reduced the 

amount of coastal land loss by 67 percent.

	TABLE 1

	Change in Total Acres of each Habitat in the MRGO-Jetty Study Area between 1985 and 1995

HABITAT			1985*		1995*		AREA CHANGE

Natural Salt Marsh	2092.10		1830.26		-261.84

Natural Upland		123.57		173.90		+50.33

Natural Shrub/Scrub	0		16.66		+16.66

Natural Bare Land	37.54		5.47		-32.07

Natural Beach		30.44		30.44		0

Total Natural Habitats	2283.65		2056.73		-226.92

Man-made Salt Marsh	190.64		245.63		+54.99

Man-made Upland		32.48		7.18		-25.30

Man-made Shrub/Scrub	65.91		99.55		+33.64

Man-made Bare Land	30.90		49.94		+19.04

Man-made Beach		0		14.84		+14.84

Total Man-made Habitats	319.93		417.14		97.21

 HABITAT TOTAL		2603.58		2473.87		-129.71

* in acres

Thompson, Bruce A., Allen, Yvonne C., Coastal Fisheries Institute, Louisiana State 

University, Baton Rouge, La., and Glas, Patricia S., Environmental Protection 

Agency, Environmental Research Laboratory, Gulf Breeze, Fl.

THE POTENTIAL IMPACT AND DISTRIBUTION OF ZEBRA MUSSEL, Dreissena polymorpha, IN 

THE LAKE PONTCHARTRAIN SYSTEM FROM INTRODUCTION VIA THE BONNET CARR SPILLWAY.

It is well known that the introduction of an exotic species into an ecosystem, 

whether intentional or accidental, can be very disruptive.  Unfortunately, we have 

a long history of introductions, both plant and animal, into Louisiana's aquatic 

environment.  Recently Louisiana has experienced an additional infestation, the 

zebra mussel, one of the most damaging exotic species present in the aquatic 

systems of North America.  Following its introduction into the Great Lakes and 

based on European studies, some scientists believed that the warm southern United 

States water temperatures would be lethal enough to the zebra mussels that 

permanent populations would not become established.  Unfortunately, this has 

proven to be incorrect and this species has spread southward in the Mississippi 

River to the delta near the Gulf of Mexico.  We have documented records from 

several dozen localities from the Mississippi River in Louisiana, and projections 

are being made about the potential for the zebra mussel to spread outside the 

Mississippi River.  It has been recorded in the Atchafalaya River and the 

potential exists for spreading via pumping stations and floodway gates.  Periodic 

openings of the Bonnet Carr Spillway gates during times of high waters presents a 

pathway for the zebra mussel to spread eastward into the Lake Pontchartrain 

ecosystem.  In the spring of 1994 and again in 1996 we have been monitoring 

densities and temporal patterns of zebra mussel larvae (veligers) to document the 

potential for their introduction outside the Mississippi River.  In 1994 high 

Mississippi River levels led the U.S. Army Corps of Engineers to do a test opening 

of a few Bonnet Carr Spillway gates and we documented that zebra mussel veligers 

were drawn from the Mississippi River into the floodway environment.  Flood gates 

were opened to maintain only about 8000 cfs, but the six mile connection between 

the Mississippi River and Lake Pontchartrain remained open for ten days.  For 

comparison, the Spillway was open for 75 days in 1973 and 35 days in 1983.  While 

the gates were open in 1994, zebra mussel veligers densities outside the spillway 

increased from 0.2 to 19.3 veligers/L, and densities within the floodway increased 

from 0.2 to 7.3 veligers/L.  There is therefore a clear conduit for introduction 

through the floodway.   So far, there is no evidence that this introduction 

resulted in zebra mussels becoming established in Lake Pontchartrain.  However, as 

has been the case in most interconnected waterways, the eventual establishment of 

zebra mussels is not if, but when.  

Previous studies have described the physical and biological character of the Lake 

Pontchartrain system.  Average maximum water temperatures are between 30O and 31OC.  

Studies have indicated that zebra mussels can be maintained indefinitely in the 

lab at 30OC, but that temperatures above this value are ultimately lethal.  Zebra 

mussels are primarily freshwater, but have been found in salinities as high as 

12ppt.  It appears as though zebra mussels will be able to tolerate salinities in 

Lake Pontchartrain (often less than 5ppt), especially the west side, provided that 

any increases in salinity are gradual.  

Changes at the ecosystem level will be more difficult to predict.  Dreissena will 

encounter a wider variety of other more closely related mollusks in Lake 

Pontchartrain than in other, less saline systems.  There are also a substantial 

number of predators in the lake.  Examination of stomachs of blue catfish from the 

Mississippi River shows this species to be a major predator of zebra mussels.  

Predators may reduce zebra mussel densities in accessible areas.  They will not, 

however, reduce densities in inaccessible areas, and the potential impacts here 

may be substantial and costly.  

Turner, R. E. Coastal Ecology Institute, Louisiana State University, Baton Rouge, La.  

WATER QUALITY, DIVERSIONS AND COST.

The 1995 river diversion into Lake Pontchartrain apparently caused an extensive 

algal bloom -- something that should be anticipated to be in common to other 

similarly-sized river diversions into Louisiana estuaries.  Louisiana wetlands may 

be the sink for nutrients to compensate for these diversions.  How water moves 

within and through wetlands determines several aspects of the nutrient exchanges 

with the overlying water.  If the residence time is short, then there is less time 

for nutrient uptake and release.  The recent experimental release of Mississippi 

River water through the Bonnet Carre' spillway resulted in virtually no changes in 

dissolved nitrogen and phosphorus as water moved from the diversion site to Lake 

Pontchartrain, probably because the times, unless deoxygenation occurs (anerobic 

conditions greatly favor ammonia and phosphate release, for example).  Further, 

the higher the loading rate, the lower the efficiency of removal in overland flow 

systems, at least.  Finally, waterflow through (or under) a wetland has a higher 

removal rate of some nitrogen and phosphorus forms than waterflow over a wetland.  

Swamps appear to take up some nitrogen and phosphorus forms, whereas wetlands with 

emergent macrophytes release these nutrients.  An exception is the brackish and 

saline marshes of western Terrebonne parish that appear to release phosphate, 

whereas the same marsh type in Barataria Bay is absorbs phosphate.

The application of results from a few measurements to broad management principles 

generally applicable to river diversions should be done cautiously if only because 

the scaling up from small experimental study areas to something the size (and 

expense) of a river diversion has not done before in Louisiana.  This is not to 

say that river diversions should not be attempted or not attempted.  Observations 

on the effects of the planned diversion at Davis Pond will shed light on the net 

transport rates and effects on phytoplankton in the downstream water bodies.

Williams, S.J., U.S. Geological Survey, Reston, VA; 

Penland, Louisiana State University, Baton Rouge, LA; 

Connor, P., Louisiana State University, Baton Rouge, LA; 

Britsch, D., U.S. Army Corps of Engineers, New Orleans, LA; 

Holmes, C., U.S. Geological Survey, Denver, CO.; 

Kindinger, J., U.S. Geological Survey, St. Petersburg, FL; and 

Lopez, J.A., Amoco, New Orleans, LA

HOLOCENE GEOLOGIC FRAMEWORK AND DEVELOPMENT OF THE PONTCHARTRAIN BASIN

The Pontchartrain Basin is the largest marginal deltaic basin in North America 

measuring about 200 km along dip and 75 km along strike.  This basin is bounded by 

incised Pleistocene terraces with small bayhead deltas to the north, the 

Mississippi River delta plain to the south/southwest, and the relict Pine Island 

barrier shoreline trend to the south/ southeast.  Over the last 150 years the 

urban growth of New Orleans and the northshore communities and the exploitation of 

natural resources have severely altered the environmental quality of the 

Pontchartrain Basin.  In 1994, the USGS began a multidisiplinary study of the 

geology, geomorphology, coastal processes, and environmental quality of the 

Pontchartrain Basin for use by Federal, state and local officials in coastal 

management and restoration planning.  This paper builds on pre-existing geological 

information integrated with new high resolution seismic, vibracore, and 

geochemical data.

The radiocarbon database for the Pontchartrain Basin chronicles a complex history 

of sea level withdrawal, rise, and stillstand followed by barrier shoreline 

development and deltaic enclosure.  During the Late Wisconsin low stand, the 

Pontchartrain region was dissected by a series of entrenched river valleys.  Sea 

level rose during deglaciation, submerging this landscape and depositing a blanket 

of transgressive nearshore deposits.  At sea level stillstand + 4000 years ago, 

the Gulf of Mexico shoreline was eroding into the Pleistocene terraces and the 

formation of a barrier shoreline trend was initiated.  Termed the Pine Island 

barrier trend, the combination of sandy sediments moving west along the mainland 

shoreline of Mississippi and those transported to the coast by the Pearl River 

supplied the material to build the large recurved spit and barrier island complex.  

Backbarrier deposits and extensive shell reefs infilled this open estuary.  About 

+ 3000 years ago the St. Bernard delta complex built out of the incised 

Mississippi River valley to the southeast enclosing the Pontchartrain Basin to the 

south and eventually including the Pine Island barrier shoreline trend.  During 

this time, the Basin began to fill with prodelta, delta front, and crevasse 

deposits.  Cypress swamp and fresh marshes formed in the upper basin and 

intermediate to saline marshes formed in the lower Basin.  During this time up to 

the present, active growth faults have also influenced basin geometry and 

geomorphology, particularly along the northshore.  This paper reports on the 

results of recent seismic, vibracore, and geochemical surveys in the basin, 

particularly its late Quaternary stratigraphy and sediment pollution history.

			

Woods, M. K., Zoology and Physiology, Baltz, D. M., Arrivillaga, A., 

and Duffy, K. C., Oceanography and Coastal Sciences, CCEER, Louisiana State 

University, Baton Rouge, La.

AN ANALYSIS OF Vallisneria americana LEAF CHARACTERISTICS NEAR BAYOU LACOMBE, 

LAKE PONTCHARTRAIN.

Wild celery, Vallisneria americana, was studied in Lake Pontchartrain near Bayou 

Lacombe, in the summer of 1995.  Our purpose was to survey the health and growth 

of Vallisneria by looking at the variables of seagrass leaf width and length, leaf 

projection rate, and longevity.  Vallisneria was collected with a core sampler 

(10.2 cm diameter) in three zones.  Zones were between 15 and 130 cm deep, and 

approximately 25, 75, and 110 m from the shore with muddy and sandy substrates.  

For each shoot, every leaf's width and length was measured.  To determine growth 

rates of Vallisneria leaves, reference points on living plants were established in 

situ by a using a rectangular horizontal plexiglass plane with two round holes.  

The plane was supported by semi-permanent reinforcing bar legs.  The grass blades 

were pulled through the holes and marked by puncturing the leaves with a 21-gauge 

needle at the level plane.  After an interval of 6-14 days, the grass blades were 

remarked using the same method and then harvested.  Distance between successive 

marks was used to estimate individual leaf growth.  Individual shoots, or vertical 

rhizomes, are attached to a horizontal rhizome.  Leaves of shoots grow in a 

rosette pattern and are numbered from youngest to oldest in relation to position 

with the youngest at the center.  We were unable to detect significant differences 

in the number of leaves per shoot; however, a slightly higher number of leaves was 

observed in the mid-zone rosettes and numbers in the near and off-shore zones were 

similar.  Mean leaf lengths (+ 1 SE) were significantly different (F-ratio = 62.9, 

df = 2 & 582, P < 0.0001) among zones:  shortest (14.1 cm + 0.54) in the 

near-shore zone, intermediate (22.9 cm + 0.67) in the mid-zone, and longest (30.7 

cm + 1.68) in the off-shore zone.  Mean leaf widths were also significantly 

different (F-ratio = 62.9, df = 2 & 582, P < 0.0001):  narrowest (0.40 cm + 0.008) 

in the off-shore zone, intermediate (0.44 cm + 0.007) in the near-shore zone, and 

widest (0.56 cm + 0.007) in the mid-zone.  Leaf area was lower near shore (6.2 cm2 

+ 0.28); however, differences between leaf area of the mid- (13.4 cm2 + 0.47) and 

off-shore zones (13.0 cm2 + 0.85) were not significant (F-ratio = 50.0, df = 2 & 

581, P < 0.0001).  Leaf growth rates differed significantly (F-ratio = 24.8, df = 

11 & 422, P < 0.0001) with age class.  The highest growth rates were in relatively 

young leaves (e.g., 1.4 cm/day + 0.1).  The older age classes had sharply reduced 

growth rates that approached zero growth in oldest classes (e.g., 1.54, 0.37, 

0.33, 0.38, and 0.12 cm/day for age classes, 0, 2, 4, 6, and 8, respectively).  

Thus, it appears that the habitat characteristics provided by Vallisneria 

americana to fishes and macroinvertebrates differed substantially with depth, 

substrate, and distance from shore near the mouth of Bayou Lacombe in Lake 

Pontchartrain.