THE OYSTER RESOURCES OF THE PONTCHARTRAIN BASIN

	Ancelet, R., Louisiana Department of Wildlife and Fisheries, New 

Orleans, La., and  Burdon, J. F., Louisiana Department of Wildlife and 

Fisheries, Slidell, La.

Oyster propagation within the Pontchartrain Basin is limited, due to 

salinity regimes, to four parishes:  Orleans, Jefferson, St. Tammany and 

St. Bernard.  The Louisiana oyster fishery is primarily a private 

lease-based industry, however, large areas of public fishing grounds 

such as those found in the basin provide a source of sack oysters for 

market and seed oysters for transplant to privately leased waterbottoms.

The public oyster grounds are discussed with emphasis on the dynamic 

environmental and physical conditions that are conducive to desirable 

oyster habitat and production.  Anthropogenic and natural processes 

which impact the quality, distribution and production of the oyster 

communities of the basin are deliberated. 

THE BONNET CARRE' FRESHWATER DIVERSION, A POLITICAL HISTORY

	Armingeon, Neil A., Lake Pontchartrain Basic Foundation, Metairie, 

La.

The U. S. Army Corps of Engineers (COE) has been responsible for the 

design and construction of numerous large-scale civil works projects.  

Examples of these include the Kissimmee River project in South Florida, 

the Tennessee-Tombigbee Waterway in Mississippi and Alabama, and the 

Mississippi River Gulf Outlet (MRGO) in Louisiana.

While many of these large-scale projects failed to live up to 

pre-construction economic expectations, and ended up harming the 

environment they were designed to enhance, all began with the help of a 

champion, or champions, in the U.S. Congress to push for authorization 

and subsequent funding.  While the authorization process is directed by 

legal statute, each civil works project's origin is unique to that 

project.  Using historical documentation, the origin of the proposed 

Bonnet Carre' Freshwater Diversion is examined.

Although the proposed diversion project is located in Louisiana, it 

originated in coastal Mississippi as a small, localized, privately 

funded study.  Through the next 20 years, it evolved into one of the 

nation's last, large Army Corp's civil works projects.  Over its 50 year 

life, the diversion will cost the nation's taxpayers over $200 million.  

The history of the proposed diversion is traced with an emphasis on the 

political maneuvering that occurred in Mississippi during the project's 

formative years.

ARE THERE REGULATORY BARRIERS TO A CLEAN LAKE?  A HOLISTIC APPROACH

	Barbe', Cheek, and Barbe', Pontchartrain Research Committee

In this presentation, we will consider how and why regulatory policies 

"may" create barriers to a clean lake.  The "Command and Control" 

policies of regulatory agencies focus on "end-of-the-pipe" problems and 

do not support long-term sustainable pollution prevention at its 

source.  These short-term fixes do not justify long-term solutions that 

support a clean lake.  Proactive, innovative, and flexible regulatory 

policies that consider adaptable, resourceful solutions will be 

necessary to achieve and maintain a clean lake.

Our focus will be on three areas of regulatory agencies whose actions 

may result in the creation of barriers to pollution prevention.  First, 

we will examine the typical profile of a regulatory employee in terms of 

tenure and subject knowledge of the diverse processes under their direct 

control.  Secondly, regulatory policies that inhibit the development and 

implementation of economically and environmentally sound waste reduction 

activities by industry.  Finally, we will address the permitting process 

by contrasting the effects of single media, multi-media, and cross media 

permits and their consequences on sustainable development.

We will conclude our presentation with a discussion of a "holistic" 

approach to pollution prevention and its long term effect on the lake.

ANALYSIS OF FECAL COLIFORM CONCENTRATIONS ON THE SOUTH SHORE OF LAKE 

PONTCHARTRAIN

	Barbe', D.E., Ph.D., P.E., Francis, J.C., Ph.D., and Seenappa, 

S.D.,Department of Civil Engineering and Biological Sciences University 

of New Orleans.

Lake Pontchartrain is a large shallow embayment located in the southeast 

part of Louisiana.  The southshore of the lake has fecal coliform counts 

that exceed the acceptable level for primary contact recreation.  The 

major source of the fecal coliform is believed to be urban runoff from 

the metropolitan New Orleans area.

The climate of the area is characterized by different precipitation/

runoff mechanisms for the summer and winter seasons.  Because of the 

combined effects of precipitation, evaporation, and transpiration, 

runoff is greater in the winter season resulting in higher fecal 

coliform counts in Lake Pontchartrain.  Runoff usually is lower in the 

summer season and fecal coliform counts in the lake are lower.

The objective of the study was to model the relationship between fecal 

coliform levels and other environmental factors.  Multivariate 

statistical analysis of historical data on fecal coliform bacteria 

concentrations in Lake Pontchartrain and concurrent water quality and 

climatic data were performed.  Water quality variables included 

temperature and salinity.  Climatic variables included wind speed and 

precipitation.  Predictive equations were derived and compared to 

current data.

Pollution Prevention and Environmental Education Efforts in Louisiana

	Branch, Bill and Coreil, Paul, Louisiana Cooperative Extension 

Service, LSU Agricultural Center, Baton Rouge, LA.

The Pollution Prevention Act of 1990 encouraged review of current 

practices to find alternatives which reduce negative environmental 

impacts.  EPA Region 6 staff promote efforts addressing pollution 

prevention and one office is specifically focused on these efforts.  

Pollution Prevention Roundtables have been conducted in all five states 

including one in Baton Rouge in June, 1993.

Phase 1 of the stormwater provisions of the Clean Water Act (CWA) calls 

for development of Pollution Prevention Plans (PPP) which include sets 

of Best Management Practices (BMPs) to reduce contamination of runoff 

from certain businesses, industries and large municipalities.  Phase 2 

will presumably extend the requirement to more and smaller entities.

The Confined Animal Feeding Operation General Permit issued under the 

CWA calls for PPP containing BMPs to reduce point source discharges.  

The Louisiana Nonpoint Source Management Plan developed by DEQ, other 

agencies and industry under the CWA calls for the adoption of BMPs to 

reduce nonpoint source water pollution.

The Coastal Zone Act Reauthorization Amendments (CZARA) call for the 

development of a nonpoint source management plan.  It will require 

adoption of "management measures"  and "management practices" which are 

similar to BMPs.  The DEQ Nonpoint Source Management Plan will coincide 

with the CZARA Nonpoint Source Management Plan.  

Intensive efforts have been underway for 18 months by an extensive set 

of committees composed of agency and industry representatives to develop 

sets of BMPs which will reduce contamination from nonpoint source and 

stormwater runoff.  These BMPs will be available to businesses, 

industries and municipalities for their use as needed.  

DEQ has contracted with firms and universities to conduct educational 

programs with public officials, householders, farmers, foresters, land 

owners and small businesses on the use of BMPs to reduce contamination 

from runoff.  Other environmental education efforts are being conducted 

by primary, secondary and post-secondary educational institutions, 

businesses and industries, public agencies, and professional, civic and 

social organizations.  These programs improve the understanding by 

citizens of the need to protect the environment and reduce nonpoint 

source pollution.

Pollution prevention and environmental education are two efforts 

receiving a major investment of time and energy by a wide variety of 

public and private sector professionals in Louisiana.  This expenditure 

will result in significant changes in attitudes and practices and the 

improvement of Louisiana's environment.  

WINTER POPULATION TRENDS OF SELECTED BIRD SPECIES IN THE LAKE 

PONTCHARTRAIN ESTUARY.

	BRANTLEY, CHRISTOPHER G. and BRUCE H. BAIRD. U.S. Army Corps of 

Engineers Planning Division New Orleans District P.O. Box 60267 New 

Orleans, Louisiana 70160.  

Christmas Bird Counts (CBC) provide useful data for evaluating the early 

winter abundance and distribution of many North American bird species.  

CBC data from 1988-1992 were analyzed for the 3 counts in the Lake 

Pontchartrain estuary: New Orleans, Reserve-Bonnet Carre, and St. 

Tammany Parish, Louisiana.  Count circle (7.5 mile radius) locations 

remained unchanged throughout the period of analysis.  Fourteen species 

that utilize open-water habitats in the area were selected for analysis 

based upon degree of habitat utilization and relative abundance in the 

estuarine system.  To standardize the counts, data were converted into 

number of birds per party hour (Schreiber, R.W. and E.A. Schreiber, 

1973, American Birds 27:711-715).  Spearman rank correlation analysis 

indicates positive trends for 8 of the 14 species surveyed and 6 

depicting negative trends.  Linear regression of log transformed data 

reveal significant positive and negative slopes for osprey (Pandion 

haliaeetus) and lesser scaup (Aythya affinis), respectively.  Short-term 

changes in the abundance of prey within the estuary are believed to be 

contributing to recent winter bird population trends in the estuary.

SUBMERSED AQUATIC VEGETATION: CURRENT STATUS AND RESTORATION RESEARCH

	John W. Burns Jr., K. P. Preston and Michael A. Poirrier.  

University 	of New Orleans.

Submersed aquatic vegetation (SAV) in the Lake Pontchartrain estuary has 

declined by >50% since 1973.   Changes in adjacent land use, urban 

runoff and shoreline modifications are believed to be responsible for 

the continued decline of SAV.  Meterological events are also believed to 

be responsible for temporal fluctuations in SAV foliar cover.  Species 

composition and community structure  were determined at five permanent 

monitoring sites along five randomly placed transects during 1991, 1992 

and 1993.  SAV foliar cover was stratified by water depth, substrate 

type and the presence or absence of shell (Rangia cuneata) along each 

transect.  In addition, SAV total areal cover was determined for the 

entire littoral zone of the estuary.

Although SAV total areal cover for the estuary during 1991 was 88 ha 

(217 acres), it was reduced to 26 ha (64 acres) when corrected for 

patchiness and bare ground within SAV beds.   This represents a 17% 

decline in areal cover since 1985.  Meterological events were determined 

to have a significant effect on SAV in Lake Pontchartrain.  SAV areal 

cover was reduced by 74% on the north shore after Hurricane Andrew 

(August 1992) and by 95% on the south shore following a severe winter 

storm (March 1993).  SAV recovery from these storms was exemplified by 

an increase in foliar cover to pre Hurricane Andrew levels by  July 

1993.  Although changes in species dominance and an increase in foliar 

cover occurred following these meteorological events, SAV have not 

recovered from anthropogenic disturbances during this study.  

A cooperative effort between the University of New Orleans, Lake 

Pontchartrain Basin Foundation and citizen volunteer groups has been 

established to restore SAV in Lake Pontchartrain.  A pilot study is 

currently underway to test transplanting techniques for Vallisneria 

americana in areas where historic populations have been reduced or 

eliminated.  

 

EFFECT OF MISSISSIPPI RIVER ON WATER QUALITY IN LAKE PONTCHARTRAIN, 

LOUISIANA

	Demas, Charles R. and Garrison, Charles, R., U.S. Geological 

Survey, Water Resources Division, Baton Rouge, La.

During the spring flood in 1979 of the lower Mississippi River, the U.S. 

Army Corps of Engineers opened the gates of the Bonnet Carre' Spillway 

to divert some of the flood waters from the river into Lake 

Pontchartrain as part of the normal flood protection measures.  

Discharge to the lake through the Bonnet Carre' Spillway ranged from 

49,000 to 250,000 cubic feet per second during the period April 20 to 

May 20, 1979.  Concurrent with this operation, the U.S. Geological 

Survey analyzed daily water-quality samples from 10 locations in the 

lake as part of a cooperative agreement with the U.S. Army Corps of 

Engineers.  Samples were collected from April 16 to June 14 and analyzed 

for physical characteristics such as pH, specific conductance, dissolved 

oxygen concentrations, turbidity, and color; major inorganic ions 

nutrients; trace metals; pesticides; fecal and total coliform bacteria; 

and chlorophyll.

Water-quality data collected in the lake during this 50-day period 

(April 16 to June 14) were compared to data collected prior to the 

opening of the Spillway (1974-March, 1979) and after its closure 

(1980-84).  These comparisons indicated that diversion of Mississippi 

River water into Lake Pontchartrain resulted in the following 

water-quality changes in the lake:

	Chlorophyll a concentrations increased.

	Nutrient concentrations increased.

	Bacteria counts (both fecal and total coliform) decreased.

	Trace metal concentrations (both total and filtered) decreased.

	Concentrations of 2,4-D increased.

	Turbidity increased at 2 sites and remained the same or decreased 

		at 3 other sites.

The observed effects of the Bonnet Carre' Freshwater Diversion on the 

water quality of Lake Pontchartrain during this period probably are not 

representative of the effects that might be expected under conditions of 

lower flows.  The large discharges during this period (49,000 to 250,000 

cubic feet per second) greatly exceeded the discharges at which the 

diversion structure will be operated (6,000 to 130,000 cubic feet per 

second).

ALGAL GROWTH POTENTIAL IN LAKE PONTCHARTRAIN, LOUISIANA, SEPTEMBER 1993

	Demcheck, Dennis K., and McGee, Benton D., U.S. Geological Survey, 

Baton Rouge, La.

In the summer of 1993 the U.S. Geological Survey, U.S. Army Corps of 

Engineers, and U. S. Wildlife and Fisheries conducted a water-quality 

investigation of nutrient and biological conditions in Lake 

Pontchartrain, Louisiana.  This abstract describes one component of the 

study, the effect of tributaries and the Mississippi River on algal 

populations.

The data collection period, for this aspect of the study, September 9-

October 1, 1993, was a period of high water temperatures and relatively 

high nutrient concentrations in the Mississippi River.  The dissolved 

nitrite plus nitrate concentration in the river water during this period 

was 1.4 mg/L (milligrams per liter) and the dissolved phosphorus 

concentration was 0.12 mg/L.  Nutrient concentrations in the middle of 

the lake during this period were much lower; the dissolved nitrite plus 

nitrate concentration in the lake water was less than 0.05 mg/L and the 

dissolved phosphorus concentration was 0.02 mg/L.

Algal Growth Potential (AGP) tests were performed at 18 sites in Lake 

Pontchartrain and its tributaries, and at one site on the Mississippi 

River.  The sites selected for sampling included the major sources of 

inflow to the lake, several stormwater drainage canals, and areas of the 

lake, were algal blooms have occurred in the past.

In the AGP tests, the green alga Selenastrum capricornutum was added to 

filtered samples of native water and these samples were inoculated with 

nutrient solutions containing various concentrations nitrogen and 

phosphorus.  The tests were designed to determine if nitrogen, 

phosphorus, or a combination of the two nutrients is limiting algal 

growth in these waters.  Three replicates of each nutrient addition were 

included in the tests, as well as a set of untreated control samples.  

Algal growth in the treated and untreated samples was monitored for 

10-12 days.

A separate test was designed to simulate the mixing that will occur 

during the operation of the proposed Bonnet Carre' freshwater 

diversion.  In this test, water from the Mississippi River and water 

from Lake Pontchartrain were mixed to form two test solutions, one 

containing 50 percent Mississippi River water and 50 percent lake water 

and the other containing 10 percent river water and 90 percent lake 

water.  Algae from the river and the lake waters were identified and 

enumerated.  Triplicate samples of water from the Mississippi River, 

Lake Pontchartrain, and the two mixed solutions were then incubated for 

5 days at 25 degrees Celsius under constant light.  After the 5-day 

incubation, algae in the samples were again identified and enumerated.

The AGP results indicated that in general, the greatest algal growth 

occurred in those test samples amended with both nitrogen and 

phosphorus.  Considerable less growth occurred in those samples amended 

with only one of these nutrients.  A student's t-test indicated that the 

increase in algal growth resulting from the addition of nitrogen alone 

was not statistically significant.  However, the doubling or tripling of 

algal numbers which occurred at most of the sites after nitrogen addition 

may indicate a biologically important trend.

Algae identification and enumeration indicated that water from the 

Mississippi River had substantially more alga species than did water 

from Lake Pontchartrain but mixing of river water and lake water, at 

least at the dilution ratios tested, would not significantly affect the 

total algal populations in the lake.  Further study would be needed to 

determine the potential affect of introducing river water into the lake 

on algal populations under different conditions than those sampled in 

this study.

ASSESSMENT OF WATER QUALITY IMPACTS TO LAKE PONTCHARTRAIN BY THE BONNET 

CARRE FRESHWATER DIVERSION PROJECT

	Drake, Marvin A., US Army Engineer District, New Orleans, New 

Orleans, La.

Lake Pontchartrain is a 616-square mile shallow estuarine embayment of 

the Gulf of Mexico bordering the New Orleans metropolitan area.  The 

lake together with adjacent wetlands and waterbodies supports abundant 

populations of fish and shellfish.  Subsidence, erosion and saltwater 

intrusion caused by natural processes and/or channel and levee 

construction have resulted, however, in the loss of wetlands and the 

loss and migration of fisheries and fishing grounds.  The Bonnet Carr 

Freshwater Diversion Project has been designed to discharge up to 30,000 

cubic feet per second into Lake Pontchartrain from the Mississippi 

River.  The resulting moderated salinity regime would greatly improve 

oyster production in neighboring Lake Borgne, its adjacent marshes and 

beyond to Mississippi Sound.  Fish and wildlife productivity would be 

enhanced in the estuarine system, and the rates of wetlands loss would 

be significantly reduced.

Recently expanded public awareness of Lake Pontchartrain's value as a 

natural resource, and of its potential for swimming and other 

recreational activities if stormwater pollution control and treatment 

measures become implemented, has raised new concerns about whether the 

project's adverse water quality impacts and other undesirable effects on 

the lake would outweigh its positive environmental aspects.  As a 

result, an Environmental Assessment was prepared by the U.S. Army Corps 

of Engineers in 1993 to supplement and update the 1984 Environmental 

Impact Statement.  The effects of progressively restrictive point 

discharge permit requirements for lower Mississippi River industries and 

municipalities, projected Lake Pontchartrain Basin pollution reduction 

efforts and other important trends and developments since 1984 were 

considered by the Water Quality Assessment, prepared as an Appendix to 

the Environmental Assessment.  The 1979 Bonnet Carr Spillway diversion 

of up to 190,000 cfs of Mississippi River floodwaters into Lake 

Pontchartrain and its extensive water quality database provided an 

unparalleled opportunity to quantitatively estimate the water quality 

effects of the freshwater diversion project upon the lake.  It was 

concluded that aside from salinity and nutrients (particularly nitrogen) 

water quality impacts would not be significant and that the net salinity 

and nutrient effects would be positive.

THE LAKE PONTCHARTRAIN BASIN FOUNDATION'S COMPREHENSIVE MANAGEMENT PLAN: 

THE PUBLIC'S VISION FOR THE BASIN.

	Dufrechou, Carlton F., Lake Pontchartrain Basin Foundation, 

Metairie, La.

The Lake Pontchartrain Basin Foundation initiated the planning process 

for the Pontchartrain Basin Comprehensive Management Plan (CMP) in 

October, 1991.  Public participation has been essential in the 

Foundation's planning process.

Phase I in the development of the CMP involved public meetings during 

which citizen's expressed their opinions on the conditions and needs of 

the Pontchartrain Basin.  Issues identified by the public were grouped 

into five major categories.

Phase II began in March, 1992.  Monthly workshops were held to address 

the public's five major issue categories.  Two groups participated in 

the workshops:  an Interagency Working Group made up of delegates from 

agencies with regulatory authority and an Advisory Group made up of 

delegates from civic, business, farming, fishing, environmental, 

industrial, and other interested groups.  Participants from these groups 

developed alternatives to address the issues identified during Phase I.

Phase III of the planning process began in January 1994.  The third and 

final will develop strategies for implementing the CMP, determining 

costs and benefits for alternatives, rank alternatives, identify lead 

agencies/groups, and pinpoint sources of funding.

Successful implementation of the CMP and restoration of the 

Pontchartrain Basin requires a partnership comprised of and supported by 

Federal agencies, State agencies, local agencies, businesses, private 

groups, and most importantly, the public.

COMPREHENSIVE ESTUARINE MANAGEMENT FRAMEWORK:  THE BARATARIA-TERREBONNE 

ESTUARY CASE HISTORY

	Flint, R. Warren, EnviroPlanning of New Orleans.

One of the toughest problems in dealing with the environment is the 

degree to which it is an integrated system - a delicate whole in which a 

change to one part affects all others.  This makes it difficult to set 

priorities for environmental action.  Therefore, strengthening 

foundations of decision-making for environmental protection should be a 

priority.

Any estuarine management decision-making process should employ a 

comprehensive ecosystem approach.  The ecosystem approach takes account 

of interrelationships among water, land, air, and living organisms, and 

considers an integrative account of interactive and emergent effects 

resulting from excessive growth of population and technology.  Estuarine 

planning and management should also encourage use of sustainable 

development principles as an integral part of decision-making.  

Sustainable development represents a quest for a healthful, productive 

ecosystem that values sustainable utilization and maintenance of 

essential ecological resources.  It involves the relationship of our 

human social, political, and economic systems to the practical resource 

base that supports us and measures the impact of the social and economic 

present on the environmental future to indicate when collective human 

actions are endangering this relationship.

Any mechanism designed to assist with comprehensive management of 

estuarine ecosystems should seek to achieve high standards of water 

quality, maintain an appropriate indigenous community of fish, 

shellfish, and wildlife, support recreational activities, protect 

beneficial uses of the estuary, and balance economic needs with resource 

protection.  Comprehensive management must also be built upon a 

foundation that promotes sustainable development of natural resources, 

recognizing that a healthy environment and a strong economy are mutually 

dependent.  How does one go about building such an instrument for 

guidance in these times of fiscal insecurity and traditional governmental 

bureaucracy?  An examination of the Case History for the 

Barataria-Terrebonne National Estuary Program might provide insight.

In an effort to achieve integrated resource management that is 

comprehensive and all-inclusive for the Barataria-Terrebonne estuarine 

ecosystem along the Gulf coast of southern Louisiana, the Management 

Conference appointed by the State of Louisiana to oversee this program 

developed a conceptual framework that organized and guided a planning 

and decision-making process for estuarine policy formulation and 

research.  The evolution and makeup of the resultant conceptual model 

will be described in detail by this presentation and its utility will be 

demonstrated with the use of several pressing contemporary 

problem-solving scenarios that this estuarine ecosystem presently faces.

The conceptual model offers a holistic view of the estuarine ecosystem 

by treating the following major components within its framework:  

natural resource characteristics, human impact problems, management and 

regulatory concerns, and over-arching issues that tend to link all the 

components together toward achieving sustainability of natural 

resources.  The description of this conceptual framework will 

demonstrate how the various components of the integrated estuarine 

system are related to one another, and how consideration of these 

interrelationships can assist the estuarine management process with 

respect to decision-making, policy formulation, and research planning.

Complex problem-solving scenarios described in the presentation will 

illustrate the complicated nature of any resource problem that might 

face the Barataria-Terrebonne system, as well as the kinds of questions 

that have to be asked in order to develop plans to solve these 

problems.  The presentation of this case history will also suggest means 

by which one might take an ecosystemic approach to decision-making 

alternatives that presents a more holistic, and at the same time clearer 

picture of all the possible outcomes, as well as the multitude of 

parameters that must be considered in attempting to achieve 

sustainability.

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.  Regression analysis of the 

available data on Secchi disk transparency in Lake Pontchartrain from 

1953 through 1993 indicates 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 to 1993.

An unbiased data set of Secchi disk transparency in Lake Pontchartrain 

is available for the recent period 1987 through 1993.  The data are 

transparency values from several 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  seven-year 

period from 1987 to 1993.

ASSESSMENT OF METALS AND ORGANICS IN WATER AND SEDIMENTS AT SELECTED 

SITES ALONG BAYOU TREPAGNIER

	George, W. J., Anderson, M. B., Preslan, J., and Adams, S. Tulane	

University School of Medicine, Departments of Pharmacology and 

Anatomy, New Orleans, LA., 

Bayou Trepagnier, a tributary of Bayou La Branche, drains into Lake 

Pontchartrain.  Contamination of this Bayou with industrial pollutants 

has resulted in its designation by the EPA as a contaminated waterway.  

Recently, we have reevaluated this Bayou with respect to metals and 

organic pollutants at a number of locations along the length of the 

Bayou.  Sites above and below suspected inflow locations were assessed 

for presence of iron, aluminum, lead, chromium, manganese, zinc, 

vanadium, cobalt, nickel, copper, selenium, arsenic, cadmium, and 

beryllium.   Sediment-digests were prepared by EPA method 3050 and were 

analyzed by inductively coupled plasma emission spectroscopy (ICP).  

Sediments were found to contain significant concentrations of iron, 

aluminum, and lead.  In water specimens taken from the same sampling 

sites and screened by ICP for the above metals, only iron and manganese 

were found to be high enough to be within detectable range.  Maximum 

observed concentrations for iron and manganese were 2110 ppb and 622 ppb 

respectively.

Methylene chloride extracts of the soils from the sampling sites were 

analyzed by gas chromatography/mass spectroscopy.  The compounds 

detected consisted of a broad range of saturated and unsaturated 

hydrocarbons and a significant quantity of elemental sulfur.  Such 

constituents are characteristic of petroleum contamination.  Absent were 

light-weight substituted benzenes characteristic of gasoline.  Oil, 

grease and non-volatile petroleum constitutents also were present in the 

soils in large quantities.

Killifish collected in Bayou Trepagnier were found to contain 

hydrocarbon compounds (octane, hexadecane, cycloundecane, hexene, 

undecene, hexacosane, heptadecane, and pentatriacontane).

CURRENT STATUS OF THE STORMWATER TREATMENT PROJECT AT THE BONNABEL BOAT 

LAUNCH.

	Gorin, Steve, Lake Pontchartrain Basin Foundation, Metairie, La.

Stormwater runoff pumped into Lake Pontchartrain from a network of 

drainage canals is the major source of pollutants along the Orleans and 

Jefferson Parish shorelines.  Constructed wetlands, located on islands 

in the Lake have been proposed as a possible system for treating this 

runoff before it is discharged into the lake.  Although constructed 

wetlands have often been used for treating wastewater, their use in any 

area is dependent on site specific factors.  Before building an 

expensive island in the lake to test the efficiacy of the use of aquatic 

vegetation on a large scale in our area, a pilot project on land has 

been designed to provide some basic data.  The objectives of this pilot 

project are:  1)  to determine if and under what conditions aquatic 

vegetation will successfully remove targeted pollutants, 2)  to 

determine the operating and maintenance requirements and the cost 

effectiveness of the system, and 3)  the characterize the output from 

the drainage canals that is pumped into the lake on a daily basis.

THE IMPACT OF INSECT HERBIVORY ON BALDCYPRESS IN FORESTED WETLANDS.

	Goyer, R. A. and Lenhard, G. J., Department of Entomology, 

Louisiana State University, Baton, Rouge, LA 70803, 

Baldcypress, a dominant component of forested wetlands, continues to be 

damaged by an outbreak of an insect herbivore, the fruittree leafroller 

(Archips argyrospila).  The focus of the population explosion of this 

tortricid caterpillar encompasses portions of the Pontchartrain Basin.  

Extensive spring-time defoliation in seasonally and permanently flooded 

areas has resulted in dramatic reduction in radial growth and has caused 

crown deterioration and tree mortality.  The interaction of insect 

herbivory with tree stresses from environmental and man-induced causes 

will be highlighted in this poster presentation.

THE INTERACTING EFFECTS OF ALLOGENIC AND AUTOGENIC AGENTS ON 

BALDCYPRESS (TAXODIUM DISTICHUM) IN THE LAKE PONTCHARTRAIN BASIN, 

MANCHAC, LOUISIANA, USA.

	Greene, Michael C., Randell S. Myers and Gary P. Shaffer, 

Southeastern Louisiana University, Hammond, La. 70402, USA.

In coastal Louisiana, the lack of regeneration of baldcypress/tupelogum 

swamp has generally been attributed to such factors as land subsidence, 

sea level rise, sediment deficits due to levee construction, 

canalization, increased salinities, waterlogging, and storms and 

hurricanes.  Factorial experiments were undertaken to isolate the 

particular cause(s) of this lack.  Among the variables considered were 

herbivory by nutria (Myocastor coypus), nutrient limitation, competition 

(from entangling vegetation), substrate type, and relative elevation.  

It was found that success was entirely dependent upon protection from 

nutria herbivory; unprotected trees suffered 100% mortality.  It was 

also determined that nutrient augmentation and release from competition 

greatly enhanced the trees' growth rates.  In subsequent studies, it was 

confirmed that relief from flood stress played an important role in 

allowing trees to become established, as did a topsoil substrate as 

opposed to one of sand.  This study indicates that biological factors 

were of primary importance in restricting the natural regeneration of 

baldcypress seedlings while physical factors played a moderating role.

THE COASTAL WETLANDS PLANNING, PROTECTION AND RESTORATION ACT:  PAST, 

PRESENT AND FUTURE.

	Hawes, Suzanne, U.S. Corps of Engineers, New Orleans District, 

and 	Kemp, G. Paul, Coalition to Restore Coastal Louisiana, Baton 

Rouge, La

The coastal Wetlands Planning, Protection and Restoration Act of 1990, 

also called the Beaux-Johnston Act, is the official means through which 

environmental damage done to Louisiana's coastal wetlands over the past 

century is to be corrected.  It was initiated by grass-roots activism 

all across south Louisiana, and is now a process run by government 

agencies and funded by taxpayers.  It is slowly and painfully evolving 

into a more inclusive and democratic enterprise that is revolutionizing 

the way environmental planning and management occurs.  The Pontchartrain 

Basin provides one of the best stages upon which this drama is being 

played out.  Plans for restoring the basin are reviewed and the 

evolution of this approach is discussed.  This process, for all its 

current flaws, is being viewed by many as a model for the Nation if 

opportunities for public involvement can be increased.

EFFECTS OF STORM EVENTS ON SEDIMENT DISTRIBUTION PATTERNS IN NORTHERN

GULF OF MEXICO ESTUARIES

	Wayne C. Isphording, Department of Geology-Geography, University 	

of South Alabama, Mobile, AL 36688, and George C. Flowers, Department of 

Earth Sciences, Tulane University,  New Orleans, LA 	70118

Ten major estuaries are present along the northern border of the Gulf of 

Mexico from Barataria Bay in Louisiana to Apalachicola Bay in Florida.  

Sediment studies that have been carried out on these bays during this 

century indicate that most have been characterized by either relatively 

consistent sedimentation  patterns or patterns that have shown a gradual 

change over the years in response to the activities of man.  Bays 

falling into this category include Barataria Bay, Lake Pontchartrain, 

Mississippi Sound, Perdido Bay, Pensacola Bay, St. Andrew Bay, and St. 

Joseph Bay.  Barataria Bay, Lake Pontchartrain, and Perdido Bay have 

been the subject of particularly detailed studies and well illustrate 

the consistency that characterizes the sediment textural patterns of 

some estuaries in the northern Gulf. Mobile Bay and Apalachicola Bay, in 

contrast, have been studied in similar detail but each of these is marked 

by significant changes in sediment texture which have taken place just 

in the last two decades.  Part of the changes observed in Apalachicola 

Bay have resulted from the construction of numerous dams by the U.S. 

Army Corps of Engineers along the Apalachicola River and its 

tributaries.  These dams markedly attenuated quantities of silt-size 

sediment that, historically, had been deposited in the bay.  More recent 

changes in the bay's sediment distribution pattern, however, can be 

directly traced to extensive scouring that occurred during passage of 

Hurricane Elena, in 1985.  This storm was responsible for the removal of 

nearly 90 million tons of sediment from the bay and returned the bay's 

depths to levels that were present during the early part of this 

century.  Storm effects on Mobile Bay were even more striking.  The 

passage of Hurricane Frederick, in 1979, removed a quantity of sediment 

from the bay calculated at 287 million tons (the equivalent of the 

deposition load of the Mississippi River each year at its mouth!).  The 

entire bay was deepened by an average of 1.5 feet, producing average 

depths that were last noted in the bay in the middle 1800's.

While hurricanes are a common phenomenon in the northern Gulf of Mexico, 

a special set of circumstances must act for them to significantly alter 

bottom sediment texture patterns.  Of particular importance are the 

storm's track, its forward movement velocity, and the bay's morphology. 

Lake Pontchartrain, and the several other northern Gulf estuaries 

mentioned previously, have been spared these special conditions and 

have, thus, remained relatively unchanged.

CITIZEN'S MONITORING IN THE LAKE PONTCHARTRAIN BASIN.

	Kenwood, Clifford M., Lake Pontchartrain Basin Foundation, 

Metairie, Louisiana.

According to the Louisiana Water Quality Inventory Report (305 (b)), 

nonpoint sources are significant contributors to Louisiana's water 

quality problems.  Not surprisingly, nonpoint source pollution has been 

identified as one of the major sources of pollution in the Lake 

Pontchartrain Basin.  One of the keys to basin-wide cleanup efforts will 

be the control of nonpoint sources of pollution.

Due to the unique nature of nonpoint source pollutants, it is necessary 

to compile data from geographically large and diverse areas.  Louisiana, 

like most states, is able to monitor only a small percentage of the 

state's waterbodies.  If the campaign to reduce the impacts of nonpoint 

pollution is to succeed, regulatory agencies will need additional help 

to monitor the state's surface waters through citizens' monitoring 

programs can provide:  public education on stream water quality, 

hands-on activities for school children and adults to learn about clean 

water, and useful information to local government about the condition of 

their waterbodies.

The Lake Pontchartrain Basin Foundation is currently involved in 

citizens' monitoring programs on four north shore rivers and the south 

shore canal system.  On the Bogue Falaya River, volunteers use a 

biological monitoring method (macroinvertebrate surveys) developed by 

the Izaak Walton League of America's Save Our Streams program.  On the 

Tangipahoa, Tickfaw, and Natalbany Rivers, volunteers measure nutrient 

levels and gather water quality samples for laboratory fecal coliform 

analysis.  On the south shore, high school students are currently 

involved in a canal monitoring program measuring nutrients and 

bacteria.  Each approach has its promises and pitfalls.  An analysis of 

each program's benefits and "workability" will be provided.

MOVEMENT OF HEAVY METAL CONTAMINATION OUT OF BAYOU TREPAGNIER

	Lynn Vogel Koplitz, Renan Bu Contreras, Joy Green, Eric Hopkins, 

Catherine Lanier, J. Michael Smith, and Remington Gross, III, 

Department of Chemistry, Loyola University, New Orleans, LA 70118

Sediment samples have been collected from Engineer's Canal, just east of 

the Lower Guide Levee of the Bonnet Carre' Floodway, from early 1992 

until recently.  They show high levels of Pb and Zn contamination 

originating from a small stream which connects the canal to Bayou 

Trepagnier.  This bayou has been noted by the LDEQ to be a contaminated 

soil area and has signs posted to that effect at every entrance to, or 

exit from, the waterway.  The metal concentrations in the canal appear to 

be increasing with time and moving downstream (north) toward Lake 

Pontchartrain.  A comparison of current Pb and Zn levels in the bayou 

with those in the canal indicates that Zn is being transported 

preferentially by a combination of physical, chemical, and biological 

means.  Zinc has apparently moved faster and further along the canal.  

Analyses were performed by x-ray fluorescence (XRF) of the dried 

sediments at Tulane's Coordinated Instrumentation Facility.

TRANSPORT OF HEAVY METALS INTO LAKE PONTCHARTRAIN VIA OUTFALL CANALS

	Schuang Liu and George C. Flowers, Department of Geology, Tulane 

University, New Orleans, LA 70118, and Wayne C. Isphording, Department 

of Geology & Geography, University of South Alabama, Mobile, AL 36688

Bottom sediment samples collected from Lake Pontchartrain near the 

Duncan Canal were analyzed for total recoverable metal using ICPES.  Cr, 

Zn, Ni, and Co levels are significantly above the average total metal 

values for Lake Pontchartrain, which, in general, fall below total metal 

values for the average shale.  Metal concentrations normalized to the 

aluminum and iron contents of sediments indicate significant 

anthropogenic input of Cd, Cr, Pb, Ni, and Zn near outfall canals along 

the south shore of Lake Pontchartrain.  The total metal concentration of 

sediments is controlled by sediment texture; strong positive 

correlations are observed between metal content and clay/organics 

content of the sediment.  Because clay is generally winnowed out of 

sediments at the mouth of the canal, metal content increases with 

distance from the mouth of the outfall canal.  Notable exceptions are 

sandy sediments in the mouth of the canal that contain anomalously high 

Cr and Ni contents.  Analyses of samples taken from various depths in 

cores indicate that metal input into the lake from the canal is 

relatively constant.

Ion site partitioning analyses of sediment samples taken from the 17th 

St. Canal indicate that, in general, metals are partitioned into stable 

sites under the physicochemical conditions that exist in the outfall 

canals and the lake.  However, reducing conditions caused by salinity 

stratification in the lake may increase the potential for metal release 

and subsequent absorption by the biota.

ABSTRACT

	Penland, Shea and Williams, Jeff

The Pontchartrain Basin is major Gulf of Mexico estuarine basin 

containing rich coastal wetlands and submerged aquatic habitats.  The 

Pontchartrain Basin if of a significant environmental, social, and 

economic importance to southeast Louisiana, in particular to the city of 

New Orleans.  Public consensus supported by scientific information 

suggest that this basin has undergone significant and widespread 

degradation over the past century.  Using aerial videotape surveys 

conducted in 1984 and 1994, a decade of shoreline changes are documented.

The Pontchartrain Basin is located in southeast Louisiana wedged between 

the Mississippi River delta plain to the south and the Pleistocene 

terraces of the Florida Parishes to the north.  The axis of the 

Pontchartrain Basin trends northwest-southeast and encompasses Lake 

Maurepas, Lake Pontchartrain, Lake Borgne, the St. Bernard marshes, 

Chandeleur Sound, and the Chandeleur Islands.  The habitats range from 

freshwater swamps and marshes in the western basin to saltwater marshes 

and barrier islands in the eastern basin.

Subsidence is an important geologic process impacting the Pontchartrain 

Basin.  The highest rates of subsidence occurs along the southern half 

of the basin where rates average 0.5-0.7 cm/yr.  In the northern half of 

the basin, the rates of subsidence decrease to 0.2-0.3 cm/yr.  The rates 

of subsidence vary as a function of Holocene thickness, organic content, 

faulting patterns, soil type, and various human activities.

Coastal land loss is a serious environmental problem found in the 

Pontchartrain Basin.  Shoreline erosion is consuming the margins of the 

lakes in the basin while wetland loss is consuming the interior swamps 

and marshes.  Rates of shoreline erosion range between 0.4 and .7. 

meters per year along the shoreline of Lake Maurepas and Lake 

Pontchartrain.  The highest rates of shoreline erosion are found along 

the Chandeleur Islands in the eastern side of the basin.  The short-term 

rate of erosion of these islands is measured at -12.2 m per year.

Wetland loss occurs throughout the Pontchartrain Basin from Lake 

Maurepas to the Chandeleur Islands.  Using the 15 quadrangles that cover 

the basin, the average rate of wetland loss can be measured at 0.12 

square miles per year.  The processes driving wetland loss in this basin 

are varied and complex.  Subsidence, salt water intrusion, storms, human 

activities, and pollution all contribute to wetland loss.

The major changes documented for the decade of 1984 and 1994 include 

shoreline erosion, loss of vegetated wetlands, determination of a 

variety of coastal structures, loss of seagrass beds, and a general 

decline in the environment.

EFFECTS OF URBAN RUNOFF ON BENTHIC INVERTEBRATES: A SEARCH FOR CAUSAL 

FACTORS 

	Michael A. Poirrier and Casey J. Rowe, Department of Biological 

Sciences, University of New Orleans, Lakefront, New Orleans, LA 70148

Storm water runoff from the metropolitan New Orleans area is pumped into 

Lake Pontchartrain through a system of outfall canals.  Although urban 

runoff is regarded as the primary source of environmental contaminants 

in the estuary, little is known about the fate and effects of these 

contaminants.  Past studies of infaunal invertebrate populations near 

the Duncan Canal in Jefferson Parish, Louisiana identified three 

intergrading faunal zones along a stress gradient which decreased with 

distance from the mouth of the canal.  Zone 1, which extended out to 150 

m, lacked mollusks and had more nematodes, capitellid polychaetes and 

oligochaetes.  Zone 2, which extended out from 150 m to 400 m had higher 

densities of the some polychaetes, and lower densities of the mollusks, 

Zone 3, was a variable recovery zone in which molluscan densities 

increased to levels similar those found in offshore reference sites.  

This study demonstrated an adverse effect on the benthic invertebrate 

populations in Lake Pontchartrain and supports the need for management 

of urban runoff entering estuaries.  Results could be used to monitor 

the effectiveness of runoff management programs.

The focus of ongoing studies is on the relative role of environmental 

factors associated with runoff in producing the adverse effect on 

invertebrate populations.  Reduced salinity, low dissolved oxygen, high 

current velocity, and contaminants in the water and sediment may all 

contribute to the observed response.  It is important to separate 

toxicity from contaminants in urban runoff from other factors such as 

salinity, dissolved oxygen and currents which may  be easier to  manage 

and don't have long-term environmental and health effects.  Acute 

sediment toxicity tests were performed on sediment samples taken 100m, 

300m, 800 m and 4.8km (reference site) from the canal mouth. Texadina 

sphinctostoma, a small benthic snail which occurs in Lake Pontchartrain, 

and the amphipod Hyallela azteca were used as test organisms.  No acute 

toxicity was detected  in any sediment samples with either test 

organism.  Acute toxicity tests were run to determine the effects of 

dissolved oxygen concentrations below 0.5 ppm and low salinity 

conditions on survival of Texadina.  Low dissolved oxygen and distilled 

water caused significant toxicity to the snails.  Preliminary data 

indicate that low dissolved oxygen and abrupt freshwater discharges play 

important roles in producing adverse effects on the biota.

	4 stations

	1)   100 m  from  mouth of canal

	2)   300 m  from  mouth of canal

	3)   800 m  from  mouth of canal

	4)   4.8 km  from  mouth of canal  (reference site)

* no significant toxicity between any stations  near the canal or 

between stations near the canal and the reference site for either test 

organism used

**  no significant difference in survival between salinities ranging fro 

m 0.5 - 2.0 ppt. however significant difference between freshwater 

conditions and   low salinity conditions

***    hypoxia has a significant effect upon survival of the snails 

0.15  - 0.5 ppm

****   Hypoxia x low salinity synergism experiment determined that 

hypoxia    has an effect upon osmoregulation of T. sphinctostoma under 

freshwater conditions

Kruskal-Wallis one-way analysis of variance was the statistical test used

AMITE RIVER WATER QUALITY TREND ANALYSIS.

	Smith, Stephanie L., formerly with the Louisiana Department of 

Environmental Quality, Office of Water Resources, Baton Rouge, La., 70884.

Water quality in the Amite River has been influenced primarily by sand 

and gravel mining, nonpoint source pollution, urban runoff and sewage 

treatment plant discharges over the past decade.  Twenty-eight water 

quality parameters were analyzed to determine the existing condition of 

the water quality and the trend of the past five years from 1986-1991 on 

the Amite River.  To define parameter variation it was necessary to 

specify the extreme upper and lower limits of the most influential 

environmental factor (flow) affecting the surface water constituents 

analyzed.  Grouping the water quality variables by flow conditions 

served to adjust for seasonal effects in the data; this improved 

accuracy in the analysis by reducing concentration variability 

associated with stochastic flow conditions generated by climatic 

changes.  The parameters showing a significant increase in instream 

concentration were arsenic, lead, and total dissolved solids.  Selected 

parameters were plotted by station location to illustrate concentration 

differences based on proximity to rural and urban areas.

 

WATER CONTROL PERFORMANCE OF THE CAERNARVON FRESHWATER DIVERSION PROJECT

	Thibodeaux, Burnell, US Army Corps of Engineers, New Orleans 

District, New Orleans, Louisiana.

Freshwater diversion has become the solution to a host of problems 

plaguing Louisiana's coastal zone - channelization, levee construction, 

subsidence, mineral exploitation, and sea level rise to name a few.  

These problems have caused a chain reaction throughout the estuaries 

thereby causing wetland loss, saltwater intrusion and related problems 

in the coastal ecology and hydrology.  The Caernarvon Freshwater 

Diversion project was conceived to alleviate the deleterious effects of 

the above problems by enhancing marsh productivity and wildlife habitat 

and increasing oyster productivity through the controlled introduction 

of fresh water to manage the estuarine salinity regime.

This paper will explore the Corp's role in this cost shared project, 

evaluate the structure's performance since it became operational in 

1991, and provide an overview of the monitoring programs implemented 

before and after construction.  In addition the paper will detail the 

development of the operational model for this unique and timely 

environmental project.

SCHOOLS WATER QUALITY STUDY

	Thomas, R.A.; Maygarden, D.F.; and Scott, R., Society for 

Environmental Education, New Orleans, LA, JEFFERSON PARISH HIGH

Urban runoff, or nonpoint source pollution, entering Lake Pontchartrain 

via the drainage canals from the streets, parking lots and yards 

Jefferson Parish is known to be the single most serious pollution source 

for the south shore.  This project, funded by a grant from the Sierra 

Club and sponsored by the Society for Environmental Education, set out 

to educate Jefferson Parish High School students about the drainage 

system and the substances that drain into it and the techniques used to 

assess the quality of the water and the health of the ecosystem.

Three high schools were involved: East Jefferson High sampled at the 

mouth of the Suburban Canal; Grace King High sampled at the mouth of the 

Bonnabel Canal; and Riverdale High sampled at the mouth of the Elmwood 

Canal. At each site, samples were taken from the canal side and the lake 

side of the pump station and the results compared to observe effects of 

urban runoff on the lake water.  The students conducted all the tests 

under the supervision of their teachers and staff from the Society for 

Environmental Education.

Weekly samples were taken over a four week period beginning September 

17, 1993.  All sampling took place in the late afternoon.

The following parameters were measured using water quality testing kits 

from LaMotte and HACH companies: pH, salinity, dissolved oxygen, 

turbidity, nitrate, phosphate and water temperature.  In addition, 

biochemical oxygen demand and total coliform were measured, the latter 

at the Elmwood site only.

During the month of September 1993, the New Orleans area experienced 

drought conditions, which affected the results of the project because 

little or no water drained from the streets of Jefferson Parish into the 

canals and the canal waters were not entering the lake.  However, the 

students were able to collect valuable baseline data and are currently 

repeating the procedure to investigate the values of the parameters in 

different weather conditions.

The findings of this initial study indicate that the water quality at the 

mouth of the drainage canals in Jefferson Parish is relatively good.  

The levels of dissolved oxygen were well above the minimum standard at 

all times. However, the levels of total coliform at the mouth of the 

Elmwood Canal was above the maximum standard and this may be used as an 

indicator that bacteria levels could be above acceptable levels.

ENVIRONMENTAL ISSUES SESSION

	Whitehurst, Andrew E. Baton Rouge, La., Citizens for a Clean 

Tangipahoa, Sedimentation on lower Big Creek in East Central Tangipahoa 

Parish: Land use change as a contributing cause, and  perceptions on the 

part of citizens and the elected parish council about sedimentation in 

parish streams.

Lower Big Creek in central Tangipahoa Parish has exhibited signs of 

increased sedimentation since approximately 1958.  Loss of persistent 

pools below the former Russelltown bridge site (1958-1978), and above 

the site (1978-1992) coupled with a generalized widening, loss of 

canopy, and loss of depth are most likely due to sedimentation from 

changing land use patterns in the Big Creek drainage basin.  The changes 

along lower Big Creek have resulted in a deterioration in fish habitat 

and a near total loss of recreational swimming holes for people. 

Temporary (timber harvest) and permanent (pasture creation) land use 

changes have been driven by market forces on the dairy and timber 

industries to varying degrees since the primary land use change in the 

area - the removal of the longleaf pine which ended around 1918.

An informal passive survey of one user group was deployed in sporting 

goods stores in Amite and Hammond to explore perceptions of the 

sedimentation problem parishwide.  There is evidence that participation 

in the survey was limited due to reluctance of citizens to record 

responses on a local and delicate issue. 

The elected Tangipahoa parish council has been unable to fully enforce 

its present logging ordinance and apparently would not support 

additional logging regulations (Best Management Practices) which may 

help ease the sedimentation problems in Parish Streams. 

SECOND PONTCHARTRAIN SYMPOSIUM 26-27 MAY 1994

Geologic Framework and Processes of the Lake Pontchartrain Basin: A 

Multidisciplinary Study of Louisiana's Premier But Troubled Urban 

Estuary

Williams, S. Jeffress U.S. Geological Survey 914 National Center Reston, 

VA 22092

The Lake Pontchartrain Basin, located on the eastern side of the 

Mississippi River flood plain, is a major Gulf of Mexico estuary/wetland 

complex of considerable environmental and economic importance to the 

south-central Louisiana region, especially New Orleans.  Public 

consensus supported by limited scientific information suggests that the 

basin, especially Lake Pontchartrain, has undergone significant and 

widespread degradation over the past half century.

The U.S. Geological Survey (USGS) undertook an evaluation of the 

critical problems affecting the basin and developed a multiyear plan of 

study, which identified several key environmental issues and recommended 

strategic actions necessary to improve scientific understanding of the 

basin's geologic character and relevant estuarine processes.

Major environmental issues identified in the study plan are:

	o Sediment and water pollution from urban and agricultural sources,

	o Lakeshore erosion and loss of wetlands and grassbeds,

	o Saltwater intrusion from canals and navigation waterways,

	o Effects of past long-term commercial shell dredging,

	o Potential effects of Bonnet Carr water diversion.

After acceptance of the plan, a multidisciplinary study of the 

Pontchartrain Basin was initiated by the USGS in October 1993.  Funding 

for the first year permits only a reconnaissance level of effort to 

assess existing geologic data and information and to start addressing 

the following five tasks detailed in the plan:

	o Geologic Framework:  Delineate shallow geologic character of the 

		basin, including the potential for faulting, subsidence 

		measurements, and detailed assessments of shell dredging 

		activities.

	o Shoreline Mapping:  Use very high-resolution remote sensing 

		instruments as well as historic maps and photography to 

		produce large-scale maps and computer databases of 

		geomorphic changes.

	o Contaminated Sediments:  Conduct geochemical analyses on suites 

		of lakebed sediments to quantify contaminated sediments, map 

		their areal distribution, and determine the sources, 

		transport pathways, and depositional sinks for fine-grained 

		sediments and pollutants.

	o Computer Circulation Modeling:  Use 3d models to simulate 

		circulation patterns and sediment flux within the basin.

	o Information Transfer/Education Outreach:  Provide interim 

		results to the public and planners involved in efforts to 

		restore and protect the Lake Pontchartrain Basin.

This study is an important extension of recent USGS field studies of 

barrier island erosion and wetland loss processes in the Mississippi 

River deltaic plain.  Not only will it address specific issues, but its 

results combined with results from previous studies will provide a more 

comprehensive scientific understanding of processes affecting the entire 

Mississippi River deltaic plain.

SUBSURFACE FAULT DETECTION USING SEISMIC DATA FOR HAZARDOUS-WASTE-

INJECTION WELL PERMITTING: AN EXAMPLE FROM ST. JOHT THE BAPTIST PARISH, 

LOISIANA

	Edward V. Zinni

The Covington aquifer is utilized as a major source of drinking water 

for east St. John the Baptist Parish, Louisiana.  A recent subsurface 

geologic study by Herbert and Hanson (1991) suggested that the Covington 

aquifer might communicate hydrologically with two hazardous-waste-

injection reservoirs thus putting the freshwater Covington aquifer in 

danger of contamination.  This paper describes the use of  integrating 

seismic-reflection and electric well-log data to determine the 

possibility of  hydrologic communication between the Covington aquifer 

and the hazardous-waste-injection reservoirs.

Cross-sections, net-sand isopachs and structure maps are constructed for 

three hazardous-waste-injection reservoirs and the Covington aquifer. 

Four previously undetected normal faults bisect the three injection 

reservoirs and the Covington aquifer.  The presence of these faults 

significantly increases the possibility of communication by acting as 

conduits and allowing vertical migration of fluids along the fault 

planes or causing  juxtaposition of sand against sand and allowing 

leakage to occur across the fault planes.  In addition, the upper 

injection reservoir is part of a fluvial system that occasionally scours 

down into the Covington aquifer, depositing sand from the injection 

reservoir interval directly on the Covington aquifer sand.  Therefore, 

the injection reservoir is in stratigraphic contact and possibly 

hydrologic communication with the Covington aquifer.

The injection of liquid-hazardous-waste into these reservoirs could 

jeopardize not only the water quality of the Covington aquifer but 

possibly other shallow freshwater aquifers should vertical migration 

occur along the fault planes.  Without the use of seismic data the risk 

of contaminating underground sources of drinking water would not have 

been properly assessed. 

INTRODUCTION

Electric well-log data is routinely used to make the subsurface 

structural interpretation (which includes fault detection) when 

permitting hazardous-waste-injection wells.  Well-log data alone can be 

misleading and does not always give an accurate representation of the 

subsurface faulting.  

Seismic data was used to delineate four faults, previously undetected by 

well-log data, that bisect three hazardous-waste-injection reservoirs 

and a freshwater aquifer.  The ability of seismic data to detect 

subsurface faulting has been demonstrated and proven in oil-and-gas 

exploration and is a more accurate way to locate subsurface faulting 

when integrated with well log data.  Fault recognition is critical in 

areas where deep-well injection is used to dispose hazardous waste.  

Faults can act as fluid conduits and possibly allow hazardous waste to 

migrate beyond its intended destination, risking contamination of 

underground sources of drinking water.

 Figure 1 is a location map of the study area.  Municipal water wells, 

located near Ruddock, Louisiana in the northeast part of the map, supply 

freshwater from the Covington aquifer to east St. John the Baptist 

Parish, Louisiana.  Approximately 19 km south-southwest of the municipal 

water wells, a chemical manufacturer has been disposing liquid hazardous 

waste into an interval encompassing the Covington aquifer for 30 years 

using four hazardous-waste injection wells.  A recent subsurface 

geologic study by Herbert and Hanson (1991) concluded that the Covington 

aquifer might communicate hydrologically with two hazardous-waste-

injection reservoirs.  

This paper assesses the stratigraphic and structural nature of the 

Covington aquifer and its relationship to the hazardous-waste-injection 

reservoirs. It also addresses the Louisiana Department of Environmental 

Qualitys' second geologic regulation pertaining to contamination of any 

underground sources of drinking water (USDW) by deep well injection of 

hazardous waste.  This regulation states that the confining zone(s) of a 

hazardous-waste-injection reservoir should be free of bisecting 

transmissive faults and fractures.

PREVIOUS WORK

Herbert and Hanson (1991) assessed the regional stratigraphic and 

structural nature of three primary injection reservoirs, informally 

termed, the 8000 ft, 4700 ft, and 3700 ft sands and their relationship 

with the base of the lowermost USDW.  Their subsurface geologic study 

encompassed an area within a 16km radius centered on the four Dupont 

Pontchartrain Works injection wells located in section 90, T11S-R7E 

(Figure 1).  The four injection wells are located within a 460m radius 

and range in depth from 1190m to 2592m.  Regional cross-sections and 

geologic maps of the three injection reservoirs, overlying confining 

zone, and base of the USDW were constructed using 186 geophysical 

induction well logs. 

The 8000 ft sand was interpreted as a continuous, deltaic lithofacies.  

Structurally the sand strikes west-east with homoclinal south dip.  One 

fault (12m  displacement) intersects the 8000 ft sand in the vicinity of 

the Frenier oil field (Figure 1).  The 4700 ft and 3700 ft sands are 

interpreted as discontinuous, highly variable, fluvial lithofacies.  

Structurally, both intervals strike west-east and show unfaulted, 

homoclinal south dip. 

The base of the lowermost USDW at the injection wells corresponds to the 

Gonzales-New Orleans aquifer (approx. 245m (800ft) below mean sea level 

(bMSL), Figure 2), whereas, 11km to the northeast the lowermost USDW 

corresponds to the Covington aquifer (between 862m (2825ft) and 1037m 

(3400ft) bMSL; Figure 6, wells 1,2,3,4,and 5).  The Covington freshwater 

aquifer is the southern extension (down-dip equivalent) of the Kentwood 

freshwater aquifer system (Nyman and Fayard, 1978) supplying east St. 

John the Baptist Parish, Louisiana. Also, the Covington aquifer is the 

updip equivalent of the 3900 ft sand at the injection wells and lies 

stratigraphically between the 3700 ft and 4700 ft injection reservoirs.

Based on their log correlations, cross-sections, and net-sand isopachs, 

Herbert and Hanson (1991) concluded that the 3700 ft and 4700 ft 

injection reservoirs and the 3900 ft (Covington) sand are not isolated 

and may be in stratigraphic/hydrologic communication.  The 

interconnection of these sands could lead to the contamination of the 

freshwater Covington aquifer, depending on the injection rates of the 

injection well and pumping rates of the municipal water wells and their 

effect on the hydraulic gradient.  The injection of liquid hazardous 

waste into the 3700 ft and 4700 ft reservoirs could jeopardize the water 

quality of the Covington freshwater aquifer. 

METHODS

Seismic data (donated by Tomlinson Geophysical Co., Inc. and P.C. 

Havens, President and CEO of Seismic Exchange Inc.) range between 24 and 

30 fold.  Asymmetrical split-spread geophone arrays were employed with 

geophone group and shot intervals of 67m and 134m, respectively, and 

hydrophone group and shot intervals of 67m and 67m, respectively, for 

lake recording.  The energy source was dynamite.  Processing included 

dip moveout (DMO) and migration.

A grid of four cross-sections, together with additional induction 

(electric) well logs are used to identify five stratigraphic units 

(Figure 2):

	A. 3700 ft injection sand 

	B. 3900 ft sand (Covington aquifer)

	C. 4700 ft injection sand

	D. shallow regional log marker 

	E. 8000 ft injection sand

The 3900 ft sand is the down-dip equivalent of the Covington Aquifer and 

will be referred to as the Covington Aquifer throughout this paper.  The 

shallow marker is an electric log signature that is recognized 

throughout the study area.  The Dupont #8 Pontchartrain Works injection 

well (section 90, T11S-7E) is used as the type log (Figure 2).  It is 

the deepest of the four injection wells (TD 2592m) and has penetrated 

all three injection reservoirs and the Covington aquifer.  The contour 

pattern of the net-sand isopach maps and the geometry of the electric 

log spontaneous potential (SP) responses are used in the interpretation 

of depositional environments.

Electric log data are integrated with 217km of reflection seismic data.  

Wells that are located within 305m of a seismic line are projected along 

structural strike and tied to that point on the line.  Subsea depths for 

each stratigraphic unit are converted to time and plotted on the 

appropriate seismic line.  The time-depth conversions are made using a 

velocity survey in section 3, T11S-R7E (Figure 1).  A velocity gradient 

map produced from this and four additional velocity surveys just outside 

the study area indicate a negligible velocity gradient. Because of the 

relatively consistent subsurface velocities, a single time-depth 

function is used for depth conversion within the study area.

Time and depth-structure maps are constructed for the three injection 

zones and the top and base of the Covington aquifer.  Time maps are 

converted to depth as described  above and subsea depths are 

incorporated at each well location.  

RESULTS

The structural interpretation differs from the Herbert and Hanson (1991) 

study.  Four south-dipping faults (Faults A, B, C, and D; Figure 3) 

bisect the Covington aquifer and the three injection zones.  Three of 

the faults (Faults A, C, and D; Figures 3 and 4a and b) are located 

between the municipal water wells and the injection wells.  Fault 

displacements range from approximately 12m, near the ground surface, to 

greater than 61m below the 8,000 ft injection reservoir and can be 

traced to a depth below 4000m (3.0 seconds; Figure 4a and b). These 

faults appear to influence the regional hydrodynamic flow.  The 

hydrocarbon accumulations of the Bonnet Carre, LaPlace, and Frenier oil 

and gas fields (Figure 1) are trapped in four-way anticlinal closures 

downthrown to Faults C and D in the study area (Voelker, 1965).  

Oil/water and gas/water contacts of these fields occur where the first 

closing contour intersects the bounding fault.  Also, in areas where 

there is no four-way closure, these faults fail to trap hydrocarbons as 

evidenced by numerous unsuccessful oil and gas wells that have been 

drilled into three-way fault closures.  Leakage is occurring along the 

fault plane and/or across the fault plane by juxtaposition of sand 

against sand.

 The stratigraphic interpretation of the 8000 ft, 4700 ft, and 3700 ft 

sands by Herbert and Hanson (1991) is corroborated by the contour 

pattern of the net sand isopach maps and the SP geometries of each 

horizon. 

The Covington aquifer, located stratigraphically between the 4700 ft and 

3700 ft injection zones, is interpreted as a fluvial lithofacies based on 

massive and blocky SP geometry and sinuous but confined contour pattern 

of the net-sand isopach (Figures 2,6, and 5).  The shale or confining 

layer thickness separating the 3700 ft injection reservoir sands and 

Covington aquifer sands varies from approximately zero to 53m (Figures 

2, 6 and 7).  The Covington aquifer differs from the other fluvial 

intervals by being deposited in a much broader and continuous fluvial 

system.  As shown by the net-sand isopach (Figure 5), the Covington 

fluvial system strikes north-south across the study area within a meander 

belt approximately 14.5km in width. The main depositional channel 

bifurcated into two distinct secondary channels, an eastern north-south 

trending channel and a western northeast-southwest trending channel, as 

indicated by the depositional thick trends on the net-sand isopach.  

Cross section D-D' (Figure 6) extends from the municipal water wells to 

the injection well and is oriented along the depositional strike of the 

northeast-southwest trending western channel.  Good correlations can be 

made between the interval from the top of the 3700 ft injection 

reservoir to the top of the 4700 ft injection reservoir.  Therefore, 

positive correlation can be made between the down-dip stratigraphic 

equivalent of the Covington aquifer (3900 ft sand at the injection well) 

where it is saline and the up-dip freshwater Covington aquifer. It is 

important to note the following: 

	1. 	Resistivity responses from wells 1,3,4, and 5 are 

		representative of fresh water.

	2. 	The SP response of the Covington from these wells is not 

		indicative of  true lithology.  The suppressed SP response 

		is a result of the decreased  contrast between the formation 

		water and the mud filtrate due to the salinity transition 

		from overlying saltwater sands into the fresh water of the 

		Covington aquifer (Schlumberger, 1989). 

	3.	The gamma ray* response of the Covington aquifer in well 2 

		is indicative of sand.  (*Gamma ray was the only log 

		available for this well.)

Figure 7 shows the 3700 ft injection reservoir sands sitting directly on 

Covington aquifer sands.  This indicates that the 3700 ft fluvial system 

occasionally scoured into the Covington interval, depositing sand on 

sand, leaving the 3700 ft sands in stratigraphic contact and possibly 

hydrologic communication with the Covington aquifer sands throughout the 

study area.  

CONCLUSIONS

	1.  Electric well-log data alone failed to delineate four faults 

		that bisect the injection reservoirs and the Covington 

		aquifer.  These faults would not have been recognized 

		without the integration of seismic data with well-log data.

	2.  Fault displacements may cause the juxtaposition of sand 

		against sand allowing leakage across the fault planes.

	3.  Faults may act as conduits allowing vertical migration of 

		fluids up or down the fault planes.

	4.  Positive correlations can be made between the down-dip 

		equivalent of the Covington aquifer (3900 ft sand) at the 

		injection well, and the up-dip Covington aquifer at the 

		municipal water wells.

	5.  The 3700 ft fluvial system occasionally scoured into the 

		Covington aquifer interval depositing  sand on sand,  

		therefore allowing probable hydrologic communication between 

		the 3700 ft injection reservoir sands and the Covington 

		aquifer sands.  

	6.  The injection of liquid hazardous waste into the 8000 ft, 4700 

		ft and 3700 ft injection reservoirs could jeopardize not 

		only the water quality of the Covington aquifer but possibly 

		other shallow freshwater aquifers should vertical migration 

		occur along the fault planes.

REFERENCES

Herbert, R.F., and Hanson, B.C., 1991, Louisiana Department of 

Environmental Quality Open File Contract Report No. 25500-91-07: 

Louisiana Geological Survey, Baton Rouge, La.

Louisiana Administrative Code, 1990, Title 33, Environmental Quality, 

part V. subpart 1, Department of Environmental Quality-Hazardous Waste, 

13, 2nd. Ed., 243-310.

Nyman, D.J., and L.D. Fayard, 1978, Ground-water resources of 

Tangipahoa and St. Tammany parishes, southeastern Louisiana. Louisiana 

Department of Transportation and Development, Office of Public Works 

Water Resources Technical Report No. 15.Schlumberger, 1989, 

Schlumberger log interpretation principles/applications: Schlumberger 

Educational Services.

Voelker, R.G., 1965, Bonnet Carre, Laplace, and Frenier Fields, in 

Braunstein, J., Oil and gas fields of southeastern Louisiana: New 

Orleans Geol. Soc. v.1, 33-43.