Anderson, A. C., Tulane University School of Public Health and Tropical 

Medicine, New Orleans, La., RECREATIONAL IMPACT OF FECAL LOADING ON LAKE 

PONTCHARTRAIN BASIN STREAMS.



There have been several epidemiological studies addressing the health 

implications of exposure to pathogens in recreational waters.  These data, 

including the study done at Lake Pontchartrain, are reviewed. Based on 

these studies, EPA recommended new bacteriological criteria for 

recreational water quality: 126 E. coli / 100 ml. fresh water or 33 

enterococci / 100 ml. fresh water. Levels of these indicators and 

sources of contamination are discussed using the Tangipahoa River as 

a model for fecal loading of Pontchartrain Basin streams. The impact 

of fecal contamination on other basin streams is also discussed.  The 

status of adoption of the new criteria organisms as bacteriological 

standards for recreational water is reviewed. The steps being taken to 

improve recreational water quality in the Pontchartrain Basin are 

outlined.  





Binet, G., St. Charles Parish, Hahnville, LA, and 

Ensminger, A. B., Wetlands and Wildlife Management Co., Inc., 

Belle Chasse, LA, HABITAT DEGRADATION OF THE LABRANCHE WETLANDS AND AN 

APPROACH TO ITS RESTORATION.



Considered the most productive wetlands within the Lake Pontchartrain 

Basin, the LaBranche Wetlands south of Lake Pontchartrain consists of 

over 14,000 acres of brackish to fresh marsh and forested swamp.  Before 

natural and man-made processes produced massive degradation and habitat 

changes of the LaBranche Wetlands, the entire area was a freshwater 

swamp and marsh complex.  Between 1970 and 1980, one-fourth of the 

LaBranche Wetlands habitat was lost due to saltwater intrusion, natural 

subsidence, channelization, and shoreline erosion.  Major contributing 

factors to LaBranche's decline has been the dredging of access channels 

for the construction of I-10, the construction of the Mississippi River 

Gulf Outlet that periodically brings saltwater into Lake Pontchartrain 

from the Gulf of Mexico, shoreline retreat of over 15' per year due to 

Lake Pontchartrain wave action, and of course natural sediment depletion 

and marsh subsidence. 



In 1984, a comprehensive marsh management plan was developed for the 

12,460 acres of LaBranche Wetlands owned and managed by the St. Charles 

Land Syndicate.  The area under management is generally bounded by Lake 

Pontchartrain, the Jefferson/St. Charles Parish line, US Highway 61, and 

Bayou LaBranche.  In February 1987, the Louisiana Department of Natural 

Resources/Coastal Management Division issued a coastal use permit for 

the plan, and a Section 404 Permit was received from the US Army Corps 

of Engineers in May 1988.  Since that time, the LaBranche area north of 

the Illinois Central Railroad (just south of I-10) has been passively 

managed as a brackish to intermediate marsh, while the wetlands south 

of the Illinois Central Railroad have been actively managed as a fresh 

marsh and swamp complex.  Structural modifications that plug or regulate 

water flow through man-made canals has greatly improved LaBranche's 

habitat for both fisheries and waterfowl production, has halted 

saltwater intrusion in the area, and has increased the land to water 

ratio within the entire complex.  Steps have also been taken to 

diversify marsh plants by implementing an annual re-vegetation program 

aimed at introducing non-native and more salt tolerant plant species to 

the area.



The LaBranche Wetlands is an excellent example of an environmental 

public/private partnership.  Over $2 million worth of marsh management 

techniques have been implemented in LaBranche since the inception of the 

plan, utilizing funds in the form of grants, mitigation, donations, and 

landowner and Parish participation.  The landowner and the Parish 

realizes the major habitat role LaBranche plays to the Lake Pontchartrain 

Basin, and has assumed an active role in preserving and enhancing its 

valuable habitat.







Boebel, R. W., Consultant, New Orleans, LA., and Crawford, Frank C., 

Crawford & Associates, Inc., New Orleans, LA., THE LAKE BORGNE AND LAKE 

PONTCHARTRAIN COMMERCIAL SEAFOOD PRODUCTION FROM 1970 TO 1989, VOLUMES 

AND VARIATIONS. 



Landings data compiled by the National Marine Fisheries Service, U.S. 

Department of Commerce, show that the volume of seafood harvested and 

sold commercially from lake Borgne and Lake Pontchartrain significantly 

increased in the Twenty (20) year span, 1970-1989.  The year 1989 is the 

last year that this federal agency recorded fishery data from theses two 

(2) state lakes. 



Six (6) types  of seafood (three (3) fish and three (3) shellfish), 

comprising more than 99% of the total harvest, show an increase in total 

poundage and total exvessel value from 2,075,100 pounds and $492,777 for 

year 1970 to 8,946,150 pounds, and $6,103,237 for year 1989.  The 

species included are Drum (black) sea trout (spotted, white), sheepshead 

(Atlantic), blue crab (hard, soft, peeler), shrimp (brown,white),and 

oyster.  All species increased over the period studied except oyster.  

black drum, sheepshead, and blue crab showed the most dramatic 

expansions of catch. 



Substantial volume variations are present for some species within this 

time span.  Causal factors may include economic changes, shifting 

demographies, and regulatory forces.  The introduction of Mississippi 

River freshwater and silt into these brackish water lakes probably 

caused some fluctuations.  Other physical changes in the environment 

were occurring.  Nevertheless, in 1989 Lake Borgne and Lake 

Pontchartrain were not hostile to these members of the biota.  Marine 

life was alive, well, and harvested in large volumes by the commercial 

fishing industry.

   





Brown, Murray L., Minerals management Service, New Orleans LA., A PUBLIC 

DOMAIN SOFTWARE PROGRAM FOR CHARTING ENVIRONMENTAL ATTRIBUTES IN LAKE 

PONTCHARTRAIN BASIN.



Although a number of excellent proprietary geographic information 

systems (GIS) are in use by environmental resource agencies/groups in 

southeastern Louisiana, there remains a need for an easy-to-use, well 

documented, public-domain software program that allows general users to 

prepare and share basic charts of environmental attributes using simple 

ASCII files.  The SEAPLOT software program, originally written for use 

by oceanographers around the globe, has been expanded to include the 

Lake Pontchartrain Basin on its regional selection menu.  Although the 

available coastline file is still rather crude, instructions are 

provided to allow the user to import higher resolution files, if locally 

available.



SEAPLOT is a menu-driven, interactive code written in GWBASIC (available 

on most DOS personal computers).  Using a specific data format described 

in the available manual, the user can create, plot, and combine files 

that depict locational information.  To a lesser degree, certain 

oceanographic parameters can be represented graphically, because the 

program is provided as source code, the user can easily extend this 

aspect of SEAPLOT to include water quality parameters.  Locational 

information that can be plotted includes boundaries, points, polygons, 

as well as associated labels and titles.  SEAPLOT is being used in 

oceanographic research to plot ocean station locations, the tracks of 

drifting buoys, water current and wind vectors, survey areas, stranded 

marine mammal sites, oil spill dimensions, instrument sites, shipwreck 

locations, and satellite analyses of ocean fronts.  A utility routine in 

SEAPLOT allows the user to add information to existing files using an 

on-screen cursor.  There is also a routine to sort data files according 

to recommended file-naming conventions. 



SEAPLOT Version 1.3 (which includes Lake Pontchartrain), with the draft 

manual and a sampler of different data files, can be obtained by sending 

one high-density, formatted, 5 1/4 inch floppy diskette to the author at 

1201 Elmwood Park Boulevard, New Orleans, Louisiana 70123-2394, U.S.A.  





Burns, J. W., Urban Waste Management and Research Center (UWMRC), M. A. 

Poirrier, Biological Sciences \ UWMRC and K. Preston, Geography \ UWMRC, 

University of New Orleans, New Orleans, LA, THE OCCURRENCE OF 

POTAMOGETON PERFOLIATUS L. (CLASPING PONDWEED), A RARE SUBMERGED AQUATIC 

VASCULAR PLANT IN LAKE PONTCHARTRAIN.



	Submersed plants of both freshwater and marine origin comprise 

important communities within estuaries, but their ecology in estuarine 

habitats is poorly understood.  Potamogeton perfoliatus L. (Clasping 

Pondweed) is a submersed aquatic vascular plant which is listed as a 

sensitive species in the coastal zone of Louisiana and is considered 

extremely rare.  Louisiana collections of P. perfoliatus are limited and 

restricted to Lake Pontchartrain and its surrounding marshes.



	Potamogeton perfoliatus was first recorded for Lake Pontchartrain 

by Riddell in 1838 near the Tchefuncta River Lighthouse.  Clair A. Brown 

also collected a specimen from the beach at Mandeville in 1945.  

Although Suttkus, Darnell and Darnell; Perret et al.; Chabreck; Turner, 

Darnell and Bond conducted studies which noted the submerged vegetation 

of Lake Pontchartrain in 1953-1954, 1971, 1972 and 1980 respectively, 

P. perfoliatus was not reported in the lake for the following 28 years.  

Montz reported P. perfoliatus to be abundant both before and after the 

1973 opening of the Bonne Carr Spillway, at Pointe aux Herbes in the 

southeastern sector of the lake.  A 1978 icthyological survey by 

Thompson and Verret, which noted submerged aquatic vegetation at 

specific stations located around the perimeter of Lake Pontchartrain, 

did not list P. perfoliatus as a species encountered.  During the summer 

of 1985, a survey of aquatic vegetation in the lake by Mayer did not 

find P. perfoliatus.  Efforts to relocate P. perfoliatus in 1988 by 

Lester were unsuccessful during an ecological inventory of the sensitive 

plants and animals for the coastal zone of Louisiana.  Brantley and 

Platt recorded a 7 m x 17 m submerged bed of P. perfoliatus 1500 m west 

of Bayou Lacombe in June 1990.  Additional smaller beds, which yielded 

fruiting specimens, were located in the same area in August 1990.  



	Recent surveys beginning August 1991 to the present have located 

submerged beds of P. perfoliatus on both the north and south shores of 

Lake Pontchartrain.  South shore beds have been located at Pointe aux 

Herbes (39 m x 26 m) and at the confluence of Irish Bayou with Lake 

Pontchartrain on the west side of the Pointe aux Herbes peninsula (50 m 

x 50 m; 15 m x 12 m; 20 m x 15 m).  North shore beds were located 

between Goose Point and the confluence of Bayou Lacombe with Lake 

Pontchartrain (15 m x 20 m; 10 m x 15 m), approximately 4.0 km east of 

Bayou Lacombe near Point Platte (150 m x 120 m) and off the swimming 

beach at Big Point (several individuals).  Attempts to relocate P. 

perfoliatus at Big Point during December 1991 were unsuccessful.  

Submersed beds of P. perfoliatus reported by Brantley and Platt were 

also relocated near Bayou Lacombe.



	Factors affecting the distribution of P. perfoliatus in Lake 

Pontchartrain are not known.  Some areas have been repopulated after an 

absence of 18 years, and growth is occurring in previously unreported 

sectors of the lake.  Its status in Lake Pontchartrain is currently 

being monitored and examined for factors which affect its distribution.







Calix, A. G.; Seeger, E.; Velado, L.; Rucker, J.; TGS Technology, Inc., 

U.S. Fish and Wildlife Service, National Wetlands Research Center, 

Slidell, La, and Handley, L. R., U.S. Fish and Wildlife Service, 

National Wetlands Research Center, Slidell, La, SHORELINE CHANGES OF 

LAKE PONTCHARTRAIN 1955-1990.



Lake Pontchartrain plays an important role in the wetland ecosystems of 

Louisiana.  Over the past few decades the lake has been directly 

affected by the urban development of New Orleans and surrounding areas.  

Shell dredging, saltwater intrusion, shoreline development, and 

pollution are some of the factors contributing to the lake's problems.  

Recently, efforts have been made to restore the lake to an ecologically 

sound and economically viable habitat for Louisiana.  The purpose of 

this study is to cartographically demonstrate the changes in the 

shoreline of Lake Pontchartrain using historical maps and recent aerial 

photography.





Conatser, W. E., New Orleans, La., PETROLEUM INDUSTRY ACTIVITY IN THE 

LAKE PONTCHARTRAIN BASIN.



The petroleum industry has had a commercially successful and 

environmentally compatible history in the waters of the Lake 

Pontchartrain Basin for over 53 years.  Gulf Oil Co. completed the first 

well in Lake Pontchartrain on July 17, 1938. Since that time 266 wells 

have been drilled in the waters of Lake Maurepas, Lake Pontchartrain, 

Lake St. Catherine and Lake Borgne.  These wells have penetrated more 

than 2,762,000' of strata for an average depth of 10,383' per well.  The 

deepest well to date was drilled to a depth of 25,600' by Placid Oil Co. 

on their State Lease 5407 in Lake Borgne.  The deepest well to date in 

Lake Pontchartrain is the Union Of California - State Lease 6753 #2 

which reached a total depth of 22,904'.



The petroleum industry has completed 86 (32.3%) of the wells drilled as 

commercial or possibly commercial.  The first commercial well was 

drilled by Atlantic Oil and Refining at Big Point Field near the north 

shore of Lake Pontchartrain in September of 1946.  Since that first 

completion the wells in the waters of the Lake Pontchartrain Basin have 

produced 10,017,352 barrels  liquid hydrocarbons and 116,204,782 MCF 

natural gas.



It is not possible to predict the future production of oil and gas from 

the lakes of the study area but the potential is considered significant.  

Currently oil and gas is produced from strata ranging in age from Middle 

Miocene through the Upper Cretaceous.  Trap types vary from elongate 

anticlines, to fault closures, to stratigraphic traps.  Prospective 

areas remain to be drilled in the study area.  New exploration 

techniques and recovery advancements could present possibilities for 

future petroleum production far exceeding those already produced.







Condrey, Richard, Coastal Fisheries Institute and Department of 

Oceanography and Coastal Sciences, Louisiana State University, Baton 

Rouge, La, HISTORICAL ECOLOGY OF LAKE PONTCHARTRAIN - BORGNE BASIN:  

1699-1950.



Once Iberville passed the buffalo plains and cypress swamps which were 

to become New Orleans (because the area had a fine path which led to 

Bayou St. John and then Lake Pontchartrain), he began looking for the 

right fork of the Mississippi.  Failing to find it (since he was on it 

and failed to recognize Bayou Lafourche as its left fork), he took a 

small bayou chocked with huge log jams (Bayou Iberville, now Bayou 

Manchac) through Lake Pontchartrain-Borgne.



Come on a voyage of discovery as we relook at this system through the 

writings and illustrations of the early explorers and visitors.  From 

Iberville and Collot, through Audubon, and Lafcadio Hearn and Rebecca 

Harding Davis, watch the massive ecological changes brought by European 

settlement.  Ponder what the system was as you consider what it might 

become.







Caraher, M. F., W. M. Dahl, and D. H. Easley, University of New Orleans, 

New Orleans, LA, COMPARISON OF SINGLE-WELL AND TWO-WELL TRACER TESTS FOR 

ACQUIRING VELOCITY AND EFFECTIVE POROSITY ESTIMATES IN THE PINE ISLAND 

AQUIFER, NEW ORLEANS, LA.



The Pine Island aquifer is a barrier spit sequence located primarily in 

the northern portion of Orleans parish, Louisiana.  this aquifer is 

approximately 25 feet thick in the study area located on the western 

edge of the University of New Orleans Lakefront campus.  Estimated 

transmissivities are approximately 3700 gal/day ft and storativity 

estimates are approximately 0.00036.  Average linear velocities are 

approximately 0.2 feet per day.  The aquifer consists of a fine-grained 

sand with shell fragments underlain by finer grained bay sediments and 

overlain by silt and clay fill pumped from Lake Pontchartrain.  This 

aquifer provides an ideal site for comparison of tracer tests. 



A small well field, which consists of four fully-penetrating wells, have 

been installed into the Pine Island Aquifer.  Both single-and dual-well 

tracer tests may be used to determine estimates of average linear 

velocity and effective porosity.  These tests may be complicated by 

minimal gradient that results in low ground-water velocities, such as 

occur in the Pine Island Aquifer.  Low velocities require extended 

breakthrough monitoring, which may be expensive if shorter well spacing 

is impractical. 



The intent of this project is to provide an inexpensive, simple, and 

relatively rapid method of estimating velocity and effective porosity in 

aquifers commonly found south of Lake Pontchartrain.  Our study utilizes 

the single-well drift and pump-back technique described in Hall et al. 

91991) and standard dual-wellpumping tracer tests.  The single-well 

drift and pump-back method allows the estimation of both average linear 

velocity and effective porosity simultaneously.  The dual-well test will 

be performed as a comparison with the single-well test, using the same 

portion of the aquifer.  The results are then evaluated to determine 

their reliability and overall utility. 







Davis, D. W., Louisiana Geological Survey, P.O. Box G - University 

Station, Baton Rouge, Louisiana 70893, NEW ORLEANS---NORTH AMERICA'S 

PREMIER BELOW SEA LEVEL CITY.



In the current popular and scientific literature one reads with repeated 

frequency articles related to the greenhouse effect on sea level rise.  

As the world turns up its global thermostat, melting the polar ice caps 

and enlarging the world's seas through thermal expansion, coastal cities 

will be at risk.  With nearly two-thirds of the planet's population and 

more than 40 of its largest metropolitan centers within the coastal 

lowlands, even a small upward movement in the earth's seas is 

significant.  A change in temperature of as much as 4o C has been 

predicted by 2030, that could elevate sea level enough to flood New 

Orleans and other coastal municipalities. 



From its inception, New Orleans was isolated from the mainland by 

cypress/tupelo swamps, marshes, and Lake Pontchartrain.  It was an 

"island city" delineated by water courses.  When surveyed in 1720 every 

block was defined by shallow ditches.  From its beginning these small 

channels established New Orleans' dependence on a drainage network.  

Levee construction began as early as 1718.  By 1720 all inhabitants were 

instructed to enclose their land in "palisades" or forfeit their 

property.  Ten years later an embankment 1.6 km long protected the 

"Vieux Carre."  Levees, therefore, are an old and integral part of the 

urban landscape.  New Orleans is part of an environmental setting that 

requires an extensive levee and pump system to manage the region's 

excess water.  



The "Vieux Carre" is the older section of the "Crescent City" and is 

built on abandoned or modern natural levees.  At 4.5 m above sea level, 

these features are the region's high ground.  They furnished the 

earliest inhabitants with a relatively dry, firm foundation for 

residential and commercial construction.  Draining the surrounding 

wetland was a major undertaking.  When the water was removed the soils 

shrank and settled and eventually subsided below sea level.  Even so, 

relatively rapid urbanization required additional space.  The only 

property available were the swamps and marshes that framed the initial 

natural levee site.  What was delineated as "uninhabitable wasteland" 

was slowly reclaimed as the region's incorporated limits increased.  



Much of the New Orleans' metropolitan complex has subsided to the point 

where in order to drain properly pumps siphon excess rainfall up into 

Lake Pontchartrain.  Human-induced negative land surfaces are producing, 

in many instances, below sea-level citizens.  Regional governments have 

learned, nevertheless, to live with this and other environmental 

dilemmas.  Canals, pumps, and large-diameter drainage pipes assist in 

keeping the neighborhoods relatively dry.  With much of the urbanized 

area less than 3 m above mean sea level, the margin of safety is 

exceedingly small.  This is particularly true for those sections of the 

levee-protected metropolitan region 2 m to 4 m below sea level.  In as 

much as arable land has always been in short supply, the only practical 

and realistic solution was to reclaim the "uninhabitable" swamps and 

marshes.  Soils associated with these aquatic habitats are subaqueous in 

origin and high in organic detritus.  When air dried, these histosols 

lose nearly 85% of their mass. The end result is the surface subsides, 

because of the loss of volume within the soil column.  



The product of reclaiming these marginal tracts is that the New Orleans' 

metropolitan region is sinking.  With a projected rise in sea level of 

1.2 mm/yr, coupled with a constant battle with subsidence, the New 

Orleans metroplex faces a challenging future.  In addition, the 

metropolitan area is at risk from hurricanes.  Under the right 

conditions, a tropical depression moving across Lake Pontchartrain's 

southeastern quadrant would move considerable water over the lakefront 

levees into the below-sea-level bowl that distinguishes parts of 

Jefferson and Orleans parishes.  For more than two and a half centuries 

the "Crescent City" and its satellite communities have been at odds with 

the elements.  Despite these issues, the region has developed, prospered, 

and flourished within this inhospitable environment, but the future must 

be considered carefully.







DeLaune, R.D and Pardue, J.H., Wetland Biogeochemistry Institute, 

Louisiana State University, Baton Rouge, La.  DISTRIBUTION OF HEAVY 

METALS IN BAYOU TREPAGNIER BOTTOM SEDIMENT.



The depositional pattern of metals was determined in bottom sediment of 

Bayou Trepagnier (located in the La Branche Wetland bordering Lake 

Pontchartrain). The majority of flow into the Bayou is from an 

industrial outfall. Eight cores were taken from Bayou Trepagnier and one 

core from Mississippi Bayou ( a control site ) along a transect 

extending to Lake Pontchartrain. Results indicated that Bayou Trepagnier 

sediment was contaminated with chromium, lead, and zinc. Chromium levels 

of over 5,000 mg/kg of sediment were measured in sediment profiles. Lead 

concentrations on the order of several thousand mg/kg were observed in 

the lower sediment profile taken near the industrial discharge sites. 

Zinc concentrations of greater then 1,000 mg/kg of sediment were 

recorded. Concentrations of metal increased with depth in the profile. 

Metal concentrations were normalized to Al in the sediments and compared 

to uncontaminated sites in Louisiana. Bayou Trepagnier sediments were 

shown to be highly enriched with respect to Cr and Pb when compared with 

other areas of the state. Sedimentation in recent years (determined from 

137Cs dating) was burying or removing metals from the surface 

environment where bioavailability is greatest.  









Delaune, R.D. and Lindau, C.W.,Wetland Biogeochemistry Institute, 

Louisiana State University, Baton Rouge, La, STABLE NITROGEN ISOTOPES 

STUDIES FINGERPRINT SURFACE WATER INORGANIC NITROGEN SOURCES ENTERING 

THE PONTCHARTRAIN BASIN.



Estuaries such as Lake Pontchartrain are generally nitrogen limiting. 

Nitrogen entering the system can influence water quality of the lake. A 

recent study investigated the use of natural abundance variations in 

15N/14N ratios for identification and tracing surface water inorganic N 

sources entering the Pontchartrain Basin.Surface water samples were 

collected from selected streams with distance from a point source in the 

northern Basin and analyzed for NH4+-N, NO3--N and associated 15N/14N 

(d15N%) concentrations. Ammonium-N from domestic sewage sources entering 

the Basin was found to have distinct d15N ranges. Domestic sewage 

discharge was traced for about 30 km downstream from discharge point 

using 15N/14N ratios. At the sewage point source NH4+-d15N values 

averaged +43% and increased linearly to +162% with distance from the 

discharge. Surface water NO3--d15N  values generally ranged from +1 to 

+99% and no significant association was observed between d15N values 

with distance from the domestic sewage point sources. The discrete 

NH4+-d15N signatures of domestic sewage compared to downstream surface 

water. NH4+-d15N values demonstrated that N isotopic ratios can be used 

as tracers for identifying the sources of nitrogen entering the 

Pontchartrain Basin. Such sources include the nitrogen in dairy manure 

entering the Tangipahoa river and septic and sewage being introduced 

into the Amite and Tickfaw rivers. Expanded studies are currently being 

initiated to further quantify nitrogen sources entering the basin.  







Demans, Charles R. and Garrison, Charles R., Water Quality Monitoring 

Activities of the U.S. Geological Survey in the Lake Pontchartrain and 

Lake Maurepas Basins 



The Louisiana District of the U.S. Geological Survey Water Resource 

Division has been involved in monitoring the water quality of surface- 

and ground-water resources of the Lake Pontchartrain and Lake Maurepas 

basins since 1927.  Surface-water samples and volumetric flow rate 

discharge measurements have been made at 210 sites in these two basins.  

Surface water quality samples have been collected at 102 sites, 

accounting for 2,187 water samples to date.  Bed samples have been 

collected at 28 of the above sites, accounting for 30 samples.  Water 

and bottom material have been analyzed for suspended sediment, 

nutrients, bacteria, major ions, trace metals, and pesticides.  

Currently, there are three active water-quality sites within the two 

basins.  These data were collected as part of cooperative programs with 

the Department of Transportation and Development, the U.S. Army Corp of 

Engineers, and the U.S. Geological survey NASQAN program.



Ground water has been sampled at approximately 1,160 sites within the 

basins, accounting for 3,823 samples.  Ground water has been analyzed 

for primarily major ions and selective nutrients, although synthetic 

organic compounds, trace metals, and bacteria have been run at selective 

sties.  Ground-water data have been collected as part of cooperative 

programs with the Department of Transportation and Development, 

Jefferson Parish Department of Water, and St. John the Baptist Parish 

Department of Water. 



The U.S. Geological Survey also has completed several interpretive 

studies within the Lake Pontchartrain and Lake Maurepas basins.  Studies 

completed on ongoing include: 



	-	Movement of bacteria in shallow ground water,

	-	Assessment of trace metals in coastal streams (Pear River, 

			Tickfaw River),

	-	Hydrology of Fritchie marsh, coastal Louisiana,

	-	Ground-water resources of southern Tangipahoa Parish, and 

	-	Several other general water-quality studies.







Devall, Margaret S. and Parresol, Bernard R.  Souther Forest Experiment 

Station, 701 Loyola Avenue, Rm. T-10210, New Orleans, LA  70113.  

ASSESSING THE EFFECTIVENESS OF SEVERAL PROTECTIVE MEASURES AGAINST 

HERBIVORY OF CYPRESS TAXODIUM DISTICHUM SEEDLINGS.



Second growth cypress remains an important source of lumber and is 

important for its ecological and aesthetic role, and for wetland 

preservation.  Louisiana contains a larger inventory of baldcypress than 

any other state, but subsidence and hydrological modification are 

reducing natural regeneration.  Planting programs have been instituted, 

but nutria and swamp rabbits have become serious deterrents to the 

success of cypress plantings in Louisiana.  This study examines the 

effect of treatments offering possible protection against herbivory by 

nutria and swamp rabbits, and assesses seedling growth (height and root 

collar diameter) with various treatments.  Treatments include 

application of tanglefoot, a sticky resin; application of ropel, a 

rodent repellent; and the use of plastic tree guards.  Study sites are a 

marsh that was formerly a cypress swamp on the U.S. Fish and Wildlife 

Service's Bayou Sauvage Wildlife Refuge and a marsh on Southeast 

Louisiana University's Turtle Cove Research Station near Pass Manchac.  

The Study is in its second year.







Dranguet, C. A., Southeastern Louisiana University, Hammond, LA., and 

Heleniak, Roman J., Southeastern Louisiana University, Hammond, LA., MAN 

IN THE BASIN: HABITATION AND FOREST EXPLOITATION IN THE PONTCHARTRAIN 

BASIN.



Man's entrance into the Pontchartrain Basin has been marked by a 

degradation of the cypress swamp that at one time surrounded Lake 

Pontchartrain.  The coming of the railroad to the western shore of the 

Lake in 1854 opened the area to commercial exploitation.  through war, 

flood, and man's utilization of the Basin's resources, the gradual 

shrinking of the forest was only inevitable. 



The purchase of vast tracts of virgin cypress stands by commercial 

lumber interests in the 1880's sealed the eventual fate of the forest.  

A short one hundred years elapsed between the introduction of modern 

transportation and logging techniques, the establishment of communities, 

and the final destruction of the swamp habitat.



  



Duffy, K. C., Dept. Oceanography and Coastal Sciences, LSU, Baton Rouge, 

LA., and Baltz, D. M., Coastal Fisheries Institute, LSU, Baton Rouge 

LA., THE INFLUENCE OF THE INTRODUCED EURASIAN MILFOIL (MYRIOPHYLLUM 

SPICATUM) AND NATIVE AQUATIC VEGETATION ON FISH NURSERY HABITAT IN LAKE 

PONTCHARTRAIN.



Quantitative samples in monospecific stands of submerged aquatic 

vegetation (SAV) and bare sands habitats have been collected on a 

monthly basis from three stations in the northeastern area of the Lake 

Pontchartrain estuary since July, 1991.  the samples of the community 

associated with the SAV beds are being collected with a Wegener ring 

(1.2 m ), in a microhabitat approach to describe the population response 

of fish,  invertebrate, and SAV species to environmental variables. 

these data are being used to evaluate the impact of an introduced SAV 

species on the community structure of coastal fishes and invertebrates 

in Lake Pontchartrain and its adjacent waters.  Historically, the 

dominant native SAV species were Vallisneria americana and Ruppia 

maritima; however, Myriophyllum spicatum became established and abundant 

in the 1970's.  In this study, we have seen dynamic changes in the SAV 

species composition that may be seasonal or directional and related to 

recent changes in lake water quality.  Presently, 9 fish and 9 

invertebrate species have been identified.  From the preliminary 

samples, the mean numbers per sample (range) for fishes  and 

invertebrates, respectively, are 12.5 (0-39), and 235.7 (11-508).  

Species of commercial and recreational interest include juvenile spotted 

seatrout and blue crab, and post-larval penaeid shrimp.   







Earl, C., Hicks, B., and Hull, F., U.S. Army Corps of Engineers, New 

Orleans, LA, JEFFERSON AND ORLEANS PARISHES, LOUISIANA, URBAN FLOOD 

CONTROL AND WATER QUALITY MANAGEMENT STUDY. 



The new Orleans District Corps of Engineers is currently conducting a 

reconnaissance study entitled, JEFFERSON AND ORLEANS PARISHES, 

LOUISIANA, URBAN FLOOD CONTROL AND WATER QUALITY MANAGEMENT.  



the purpose of the study is to consider measures to alleviate rainfall 

flooding in the parishes and to improve the water quality of stormwater 

discharges into Lake Pontchartrain, Lake Borgne, and the Barataria 

Estuary. 



Our goal for the water quality management plans under consideration is 

to reestablish the designated use of the receiving waterbody, such as 

making it swimmable and fishable. 



During the reconnaissance phase we rely heavily on existing data.  We 

determined the impacts of stormwater runoff using a preliminary 

screening procedure recommended by EPA.  Based on research of the best 

available technology, we will estimate the cost and effectiveness of the 

various water quality management plans. 



The Reconnaissance Report will discuss a wide range of alternatives, 

such as source controls, in-line treatment, and end-of-pipe treatment. 



  



Ellis, L. E., Biological Sciences / Urban Waste Management and Research 

Center (UWMRC), UNO; Francis, J. C., Biological Sciences / UWMRC, UNO; 

and Tracy D. K., Biological Sciences, UNO.  DETERMINATION OF FECAL AND 

TOTAL COLIFORM LEVELS IN LAKE PONTCHARTRAIN BY POLYMERASE CHAIN REACTION 

(PCR).



Fecal coliform and total coliform levels were monitored in Lake 

Pontchartrain over a several month period using oligonucleotide primers 

for detection of the lacZ and uid DNA sequences by PCR.  Good 

correlation was realized between PCR detection and standard method 

procedures.  Refrigerated storage of water samples prior to PCR 

detection was evaluated.  Bacteria were detectable for 10 days but 

showed significant declines after 48 hours.  High fecal and total 

coliform levels in Lake Pontchartrain appear to be associated with high 

turbidity of the water.







Emmer, R. E., College of Urbanand Public Affairs, University of New 

Orleans, New Orleans, LA.  SHRINKAGE OF THE PONTCHARTRAIN BASIN, THE 

NEED FOR A COOPERATIVE REGIONAL APPROACH.



The Pontchartrain basin in shrinking in our perception of its size, the 

remoteness of the headwaters, the vastness of its waterbodies, the 

supply of natural resources, and the rapidity of population growth and 

how soon their presence is felt by neighbors.  Tradition segments the 

basin into four regions:  metropolitan New Orleans or the south shore; 

the river parishes from St. Charles to Iberville Parish; the north shore 

of St. Tammany, Washington, and Tangipahoa Parishes; and the distant 

headwaters, the Amite River watershed including East Baton Rouge, 

Livingston, East Feliciana, and St. Helena parishes.  these regions have 

historically acted independently for several reasons.  Culturally, they 

were distinct, i.e., Anglo-Saxon vs. French vs. The City.  Second, the 

regions were separated by distance. Trips between regions as late as the 

1940s were major excursions because of the absence of all-weather roads 

and bridges over major waterbodies such as the Rigolets, Pass Manchac, 

and the many rivers.  Third, the economic foundation of each region was 

different.  Finally, popular beliefs and attitudes ranged from Laisse 

lse bons ton rouler to strict biblical followings. 



Communities were scattered clusters of homes and businesses along the 

Mississippi River; isolated groupings of stores and residences at 

cross-roads or spaced along the bayous, railroads, and highways.  

Because these enclaves were small they were insulated from their 

neighbors and, thus, were little affected by or had little effect on the 

nearest villages, much less Lakes Maurepas or Pontchartrain.  The 

Pontchartrain minimal if any significant adverse impacts extending 

beyond the boundaries of the community.  Post World War II growth, 

improved highways, the automobile, and industrial development have 

changed the basin from overall rural to an emerging suburban/urban 

system.  Time and space are compressed and with an increasing population 

problems are magnified.  The basin has become one community whether it 

wants to be or not.  I turn, our common problems must be approached in 

new ways. 



The Pontchartrain basin as one community faces many institutional and 

environmental problems.  Federal, state, and local laws and 

jurisdictions overlap and, in many instances, conflict in mission and 

authority.  In addition, the private landowner is concerned with his/her 

right to use property in a way that benefits them.  Water quality, 

wetland loss, harvesting of renewable resources, and extraction of 

minerals are issues that confront decision makers in the  basin and can 

no longer be ignored.  Planning offers the vehicle for addressing these 

issues in a timely and systematic manner.  Former Governor of California 

Edmund G. Brown said, "planning is thinking ahead intelligently ..."  

and an idea that has received wide acceptance.  In fact, it is 

methodically avoided by many parishes and municipalities.  Such as 

negative attitude requires modification if the institutional and 

environmental problems of the basin are to be solved in a timely 

fashion.  The Lake Pontchartrain Basin Foundation through a grant from 

the Environmental Protection Agency is undertaking a basin planning 

process that will confront many of the most difficult institutional and 

environmental problems in the basin.  What evolves will be a formal 

regional cooperative mechanism for formulating positive actions that 

result in a healthier and safer place to live for the people in the 

basin. 







Farabee, M.V., and R.C. Cashner, Department of Biological Sciences, 

University of New Orleans, New Orleans, LA, DISTRIBUTION OF FISHES AND 

COMMUNITY STABILITY IN BAYOU LACOMBE.



Bayou Lacombe is a relatively small drainage system tributary to the 

northeastern section of Lake Pontchartrain.  Based on records from fish 

collections made since 1951, a total of 77 resident and migratory 

species have been documented for the system.  Bayou Lacombe has been the 

focus of four major ichthyofaunal surveys.  The most extensive study was 

done by Sobczak, in which 10 stations were sampled monthly from August, 

1973 to August, 1975, and the most recent survey included monthly 

samples at five sites from November, 1988 to October, 1989.  Numerical 

dominants in the upper reaches of Bayou Lacombe include grass pickerel, 

chubsuckers, black bullhead, bayou topminnow, mosquitofish, dollar 

sunfish, and warmouth.  The middle of the river has greater numbers of 

cyprinids, blackspotted topminnow, brook silverside, and longear 

sunfish.  The longitudinal pattern of distribution of fishes in Bayou 

Lacombe is characterized by a rather abrupt change in the fauna between 

upper, middle, and lower reaches, rather than addition of species.  

Morisita's Index (Im) and Percent Similarity Index (PSI) indicate that 

the greatest dissimilarities between fish assemblages occur between the 

lowermost stations and those above tidal influence.  Stations near the 

mouth of Bayou Lacombe are characterized by euryhaline forms, such as 

bay anchovy, Gulf menhaden, inland silverside, sciaenids, and gobies.  

Community similarities were calculated for five common stations between 

the 1973-75 and 1988-89 surveys.  Relatively low values for Im and PSI 

may indicate less stability and persistence of fish communities over 

time than reported for midwestern streams.  The most abundant species, 

the blacktail shiner, collected during the 1973-75 study was not 

represented in any of the 60 collections made during the 1988-89 survey.







Francis, J. C., Biological Sciences / Urban Waste Management and 

Research Center (UWMRC), UNO; Wijesundera, V., UWMRC, UNO; Barbe, D. E., 

Civil Engineering / UWMRC, UNO; Mulino, M. M.,  Steimle & Assoc., Inc., 

Metairie, La.; and Poirrier, M. A., Biological Sciences / UWMRC, UNO.  

HISTORIC CHANGES IN SECCHI DISK TRANSPARENCY IN  LAKE PONTCHARTRAIN.



     A major environmental concern about Lake Pontchartrain is an  

assumed long-term decrease in water clarity.  Available data on  Secchi 

disk transparency in Lake Pontchartrain from 1953 through  1990 were 

examined to determine if changes in water clarity had  occurred.  Linear 

regression analysis of Secchi disk transparency  versus time indicated a 

statistically significant (5% level)  decrease in transparency with time.



     The relationship between Secchi disk transparency and two 

environmental factors, salinity and wind speed, were studied using 

regression analysis.  The analysis revealed a statistically  

significant, positive relationship between water clarity and salinity, 

and a statistically significant, negative relationship  between water 

clarity and wind speed.  Further analysis indicated  that neither 

average annual salinity nor average annual wind speed had realized a 

statistically significant change during the period from 1953 through 1990.



     Secchi disk transparency data were adjusted for the effects of 

salinity, wind speed, and both salinity and wind speed.  The base for 

adjustment in each case was the long-term average of the  variable for 

which adjustment was being made.  Regression of  Secchi disk 

transparency versus time, with adjustment for salinity, revealed a 

statistically significant relationship,  indicating that adjusting the 

data for the effect of salinity had  not removed the long-term decrease 

in water clarity.  However,  regression of Secchi disk transparency 

versus time, with adjustment for wind speed, indicated that there was no 

longer a  statistically significant relationship between Secchi disk  

transparency and time.  Adjusting the data for the effect of wind  speed 

had removed the long-term decrease in water clarity.  Also,  regression 

of Secchi disk transparency versus time, with adjustment for both 

salinity and wind speed, revealed no statistically significant 

relationship, indicating that adjusting  the data for the effects of 

both salinity and wind speed had  removed the long-term decrease in 

water clarity.  



     Analysis of variance of monthly salinity data from 1953 through 

1990 revealed a statistically significant monthly seasonality with the 

highest values occurring in November and the  lowest values occurring in 

May.  Similarly, analysis of variance  of monthly wind speed data from 

1953 through 1990 revealed a  statistically significant monthly 

seasonality with the highest  values occurring in February and the 

lowest values occurring in  August.  These seasonal effects are not 

equally represented in  the available data 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 1990.







Goyer, R.A., G. J. Lenhard, J. L. Chambers, LA Agricultural Experiment 

Station, LSU, Baton Rouge, LA, and V. R. Van Sickle, U.S. Fish & 

Wildlife Service, National Wetlands Research Center, Lafayette, LA,  

HERBIVORY IN BALDCYPRESS:  A THREAT TO THE PONCHARTRAIN BASIN



The future of the baldcypress is closely linked to its ability to 

withstand environmental, biological and man-caused stresses.  Currently, 

all three of these categories of stress are impacting cypress in south 

Louisiana and, particularly, threaten trees in and near the Ponchartrain 

Basin.  Studies underway by the authors are evaluating the impact of an 

herbivore - the fruit tree leafroller (Lepidopter: Tortricidae) - on 

baldcypress.  Further evaluations are being conducted to ascertain the 

interaction(s) of herbivory with flooding caused by man made and 

environmental changes (e.g., global warming and associated changes in 

hydrology).  Studies to date have revealed continued expansion of fruit 

tree leafroller populations into the periphery of the Ponchartrain 

Basin.  In areas having experienced repeated defoliation of cypress, 

radial growth has shown marked reduction.  Additionally, crown 

deterioration, increased transparency and dieback have occurred along 

with scattered tree mortality.  The threat to baldcypress results from 

herbivory coupled with changes in hydrology.  Sapling and pole-sized 

cypress exhibiting high live-crown ratios appear most heavily browsed.  

Transect evaluations presently underway are aimed at evaluating severity 

of herbivory in relation to seasonal flooding regimes.  Rates of 

refoliation on both mature and young saplings are compared to further 

elucidate the ability of cypress to respond to herbivore and flooding 

stresses.







Hardy, J. W., Southern Regional Climate Center, Department of Geography 

& Anthropology, Louisiana State University, Baton Rouge, La, 70803, 

FRESH WATER INPUT INTO LAKE PONTCHARTRAIN.



Fresh water input into Lake Pontchartrain will be determined for a wet 

year and dry year.  The amount of runoff generated by each drainage 

basin of Lake Pontchartrain will also be examined.  Fresh water input 

into Lake Pontchartrain will be found in part from measured runoff at 

gaging stations along Highway 190.  The Thornthwaite water budget model 

will be used to estimate the surplus water, hence runoff, for the part 

of the Pontchartrain drainage basin below the gaging stations.  Actual 

evaporation and the change in soil moisture storage will be subtracted 

from precipitation to give the surplus for the ungaged uplands.  The 

freshwater input into Lake Pontchartrain from the ungaged swamps, 

marshes, and lakes will be found by subtracting potential evaporation 

from precipitation.







Hastings, Robert W., Turtle Cove environmental Research Station, 

Southeastern Louisiana University, Hammond, LA, SURFACE DRIFT MOVEMENT 

OF LARVAL MARINE FISHES AND OTHER ORGANISMS THROUGH PASSES OF THE UPPER 

LAKE PONTCHARTRAIN ESTUARY.



The fish fauna occurring in the oligohaline upper Lake Pontchartrain 

estuary consists of about half freshwater species and half marine.  

Freshwater species are present throughout the year whereas most marine 

species are seasonal in their occurrence, leaving the upper estuary for 

the winter.  A major occurrence, leaving the upper estuary for the 

winter. A major influx of such species occurs in the spring as larvae 

and early juveniles.  Surface plankton net sampling has been conducted 

to monitor patterns of movement for several fish species, such as bay 

anchovy (Anchoa mitchilli), gulf menhaden (Brevoortia patronus), gulf 

pipefish (Syngnathus scovelli), naked goby (Gobiosoma bosci), and 

tidewater silverside (Menidia beryllina), as well as several 

invertebrates such as blue crab (Callinectes sapidus ).  Samples have 

revealed significant seasonal, diel, and spatial patterns of occurrence 

for several species common in the estuary.  Thus they may exercise 

significant control over their movements, even though they are small and 

appear to be poor swimmers.  Although open waters of the upper estuary 

are clearly used as nursery habitats for such species, their use of 

enclosed marsh canals and bayous may be more limited.  Studies are 

continuing to address such movement (or lace of movement) of small 

planktonic organisms into enclosed waters, and how diel variation in 

activity patterns affects their patterns of occurrence in surface 

plankton samples. 







Keim, B.D., Southern Regional Climate Center, Department of Geography 

and Anthropology, Louisiana State University, Baton Rouge, Louisiana 

70803.  STORM FREQUENCIES AND STORM RUNOFF INTO LAKE PONTCHARTRAIN. 



The large number of recent heavy rainstorms in southeastern Louisiana 

has raised concerns about changing frequencies and magnitudes of heavy 

rainfall in the area.  A changing heavy rainfall climatology over the 

Lake Pontchartrain Basin may have noteworthy impacts.  Most storm runoff 

from New Orleans is discharged into the lake and is obviously important 

to the lake's water quality.  Furthermore, storm runoff from the rivers 

draining the Florida Parishes transports agricultural wastes into the 

lake and influences lake salinity levels.  This paper examines the 

historical storm events in metropolitan New Orleans and the Florida 

Parishes from the nineteenth century to the present.  The seasonality 

and synoptic situations of storm rainfall will also be examined.







Lawler, G. C., Delgado Community College, New Orleans La., and Hartzog, 

L., Army Corps of Engineers, New Orleans, LA., BASELINE POLLUTANT DATA 

ON WATER COLUMN, SEDIMENT, AND BIVALVE TISSUE SAMPLES FROM THE INNER 

HARBOR NAVIGATION CANAL, CHEF MENTEUR PASS, AND THE RIGOLETS.



As part of the environmental impact statement supporting the Army Corps 

of Engineers' Hurricane Barrier Protection Plan, pollutants in the water 

column, sediment, and bivalves of the Inner Harbor Navigation Canal (

IHNC), Chef Menteur Pass, and The Rigolets were investigated.  This 

investigation was carried out in tow phases.  In phase I, methods were 

developed, the three passes were screened for pollutants, and replicate 

samples were analyzed to determine the number of samples required to 

achieve reasonable analytical precision.  Phase I culminated with the 

production of a sampling protocol, which included various sampling 

options and tables relating numbers of samples to analytical precision.  

Phase II, which was designed to detect seasonal fluctuations of 

pollutants, was aborted with the Hurricane Barrier Protection Plan was 

abandoned.  The first samples were collected for analysis in May of 

1980.  The data generated from these and subsequent analyses qualify as 

baseline data for these location and matrices because the analyses were 

carried out under rigorous conditions of quality assurance and the 

analytical techniques employed were state-of-the-art.  The major 

analytical effort was directed toward detecting and quantifying EPA 

designated priority pollutants.  In addition, organic fractions were 

routinely searched for compounds of probable anthropogenic origin.  

Water samples were analyzed for asbestos, heavy metals, base-neutral and 

acid extractable organics, organochlorie pesticides and polychlorinated 

biphenyls, volatile organics, acrolein and acrylonitrile, total cyanides 

and total recoverable phenolic.  Sediment samples were analyzed for 

heavy metals, total base-neutral extractable organics, individual 

base-neutral extractable organics, organochlorine pesticides and 

polychlorinated biphenyls, and volatile organics.  Bivalve tissue 

samples from oysters (Crassostrea virginica) and clams (Rangia cuneata) 

were analyzed for heavy metals, total base-neutral extractable organics, 

individual base-neutral extractable organics, organochlorine pesticides 

and polychlorinated biphenyls, and voltile organics.  The results of 

these analyses were compiled in seven data reports submitted to the Army 

Corps of Engineers in association with the "Nutrient and Toxic Substance 

Chemistry of Chef Menteur Pass, The Rigolets, and Inner Harbor 

Navigation Canal, Lake Pontchartrain, Louisiana" program.  The results 

of dissolved inorganic nutrient analyses conducted on the water samples 

were included in the data reports.     







Lopez, John A., Amoco Production Co., New Orleans La.,  POTENTIAL 

SIGNIFICANCE OF ACTIVE FAULTS IN LAKE PONTCHARTRAIN.



Examination of conventional seismic data collected in Lake Pontchartrain 

leads to the compelling conclusion that the eastward extension of the 

Baton Rouge-Denham Springs faults system is within Lake Pontchartrain 

and not as previously mapped on the northshore of the lake.  The 

Pleistocene/Holocene contact previously mapped as faults on the north 

shore is probably a depositional contact.  The faults within the lake 

are presently active as is the Baton Rouge/Denham Springs fault system.  

Evidence for recent movement on the faults within the lake is strongly 

suggested by offset of the bridges which cross the lake.  Offset varies 

from 2 to 6.5 inches depending on the age of the bridge.  Movement on 

the fault is approximately 1 inch per decade (.25 cm / year).  Less 

detailed mapping suggests the fault system extends into Chandeleur 

Sound.  Thus the Baton Rouge-Denham Springs fault system is a regional 

basement fault system extending 120 miles from Baton Rouge to Chandeleur 

Sound.  One of the probable effects of this fault system is to trigger 

small earthquakes, such as the 1987 Irish Bayou earthquake.  Other 

historic earthquakes located 5 to 20 miles south of the fault trace may 

have also been related to the fault system.  Past activity suggests that 

an earthquake hazard is minimal.  Other consequences or significant 

questions in relation to the active faults are:



	1) The current high rate of movement on the faults is probably

	higher than in the geologic past.  So why does movement on the

 	faults appear to have accelerated in the Holocene?



	2) The coincidence of the regional fault system within Lakes 

	Maurepas, Borgne, and Pontchartrain suggests a genetic

 	relationship.  Do prior models for the formation of Lake

 	Pontchartrain need to re-evaluated?

	

	3) At least two significant studies of ground water aquifers

 	in Lake Pontchartrain indicate that some of the faults do seal

 	some of the aquifers.  Since the faults are a series of 

	discontinuous faults the hydraulic connection of fresh and saline

 	aquifers is complex and probably intimately related to 

	faulting in the lake.



	4) The high rate of fault movement conflicts with the 

	interpreted top of the Prairie Terrace accepted by most 

	workers.  Is the second weathered surface and not the first 

	weathered surface in the lake truly the top of Prairie 

	Terrace?



Some of these questions may be academic and others may have more civic 

significance,  but all of these and others can be addressed with further 

basic research.  Much can be gained by research efforts by greater 

exchange of data and ideas between professionals which generally operate 

in different institutional or commercial spheres.     







Otvos, E. G., Gulf Coast Research Laboratory, Ocean Springs, MS 

39564-7000, LAKE PONTCHARTRAIN BASIN EVOLUTION; LATE 

PLEISTOCENE-HOLOCENE GEOLOGICAL HISTORY.



	The Pleistocene sedimentary cycle that preceded Holocene evolution 

of the lake system, climaxed 128-122 ka B.P.during the Sangamonian 

Interglacial.  It produced the muddy-sandy, microfossil-rich, 

marine-to-estuarine Biloxi Formation, c. 13.5 m thick under 

Fontainebleau State Park and south Hancock County, MS, and overlain by 

the thin regressive alluvial Prairie unit. The oxidized, seaward-sloping 

Prairie coastwise surface, cut by approximately E-W-trending  faults, 

forms the northern border of the Lake. A buried segment of the Gulfport 

barrier complex, the Gulfwide Sangamonian high shoreline indicator, 

occurs at nearby Port Bienville, MS. The previously reported presence of 

another Pleistocene segment beneath the Lake, c. 10 km from the north 

lake shore, is not yet proven. (Earlier, this 3-5 m thick sand body, 

appearing as channel-filling beneath the muddy lake deposits in the 

Causeway foundation-drillholes, has been described as the "Miltons 

Island Beach Trend", Saucier's assumed earlier Holocene lake shoreline.) 

Stream channels became deeply incised in the general area and clusters 

of wind-blown dunes formed along river floodplains in the Florida 

Parishes during subsequent marine lowstands of the Wisconsinan  glacial 

interval. By c. 4.5 ka B.P., Holocene transgression filled most of the 

"Pontchartrain Embayment" with higher salinity but still brackish 

waters. Westward-directed littoral drift from Pearl River delta shores  

5.0 -3.7 ka constructed a chain of sandy underwater shoals, probably 

also including small barrier islands in front of the embayment. These 

barrier sand bodies are 6-12 m thick. Occasionally, they extend near, 

even slightly above the land surface (Pine and Oak "Islands" in New 

Orleans East). 

	Sediment and microfossil data marked steady eastward growth of the 

Mississippi delta toward the shoals. A delta spur separated Lake 

Maurepas from Pontchartrain. By 4.0 ka, the Morrison Rd. Pit area (at 

Frenchmans Wharf Apartments, on Interstate Highway 10, New Orleans 

East), was covered by subdelta clays and sandy muds (Otvos, 1978). 

Recently obtained radiocarbon dates (Dr. F. Stapor, Jr.) indicate that 

shore processes continued 4 km to the east at Bullard Rd. until c. 3.5 

ka. As late as 3100-2900 yr B. P. barriers of the separate South 

Hancock-Sauvage trend were active shore zones in easternmost Orleans 

Parish. 

	Intensive regional delta growth (St. Bernard and other subdeltas 

in present Orleans-St. Bernard Parishes) subsequently buried the two 

barrier trends under the extensive marshlands. Pontchartrain's waters 

freshened as a wide belt of delta land gradually cut off the bay from 

the Gulf. Lake beaches and numerous Indian midden mounds date from this 

period. Cessation of delta growth and continuing subsidence soon 

increased shore erosion. Improved connection with the Gulf, most 

recently through the man-made Gulf Outlet Channel, slightly increased 

salinities. Intensive commercial clam shell-dredging in recent decades 

(Otvos and Sikora, 1990) liquefied central lake sediments and profoundly 

impacted bottom biota, including the Rangia bivalve fauna. Lake tidal 

gage data indicate minor subsidence probably along faults. Tectonic and 

eustatic changes, sediment compaction and marsh degradation -related to 

natural and man-induced causes- will remain critical factors in future 

basin development.







William S. Perret, L. Brandt Savoie, John F. Burdon and Karl A. Mapes.  

Louisiana Department of Wildlife and Fisheries.  The Fisheries of the 

Pontchartrain Basin.



	the Lake Pontchartrain Lacustrine Basin is bordered by 8 parishes 

and drains 8 additional parishes of Southeast Louisiana and numerous 

counties of southwest Mississippi.  Preliminary data indicate that in 

1990, -*-% (-*- pounds) of Louisiana's commercial fishery landings were 

within the basin.  Historical records indicate that the Basin has 

contributed significantly to the states fishery production.  Landings 

include species caught from freshwaters to adjacent continental shelf 

waters of the Gulf of Mexico. 



	In 1990 a significant number od commercial and recreational 

fishermen resided within the Basin.  Freshwater recreational fishermen 

from the Basin accounted for 22% (108,107) while saltwater anglers 

accounted for 42% (88,331) of the states licensed resident population.  

commercial licenses sold within the Basin accounted for 31% (32,612) of 

the state's total. 



	Utilization of the Basin's fishery resources by recreational and 

commercial groups have continued to increase during the last three 

decades but overall fishery production has not kept pace.  While 

landings may have increased in some cases, the addition of more user's 

has resulted in a decreased catch per effort. 



	The Basin's fishery has been significantly impacted by wetland and 

estuarine habitat loss or modification due to such activities as 

leveeing, reclamation, subsidence, sea level rise, erosion, toxins and 

eutrophication.  Salinity modifications often accompany habitat 

modifications and may significantly impact the distribution of fishery 

species.  Point and non-point source discharges of pollutants have 

impacted the quality of the harvest waters of many species, especially 

the American oyster.  Introduction of species or pathogens not endemic 

to the Basin may also pose a threat to the fisheries. 



	Its diverse habitats and resources portray a region that is 

providing adequate fishery production, despite its problems.  However, 

it evident that there are many significant economic and social changes 

occurring with more on the horizon.  Sustaining or enhancing the fishery 

resources of the Basin has no single solution.  conservation, 

implementing comprehensive wetland management plans, implementing 

comprehensive inventories of habitat types, and strengthening the 

environmental consciousness of all who live, work and play in the Basin 

will help. 



*Landing data is forthcoming for NMFS. 







Powers, S.P., Poirrier, M.A., and Yund, P.O., Department of Biological 

Sciences and the Urban Waste Management and Research Center, University 

of New Orleans, New Orleans, Louisiana 70148. THE EFFECTS OF NEW ORLEANS 

URBAN RUNOFF ON THE BENTHIC COMMUNITY OF SOUTHERN LAKE PONTCHARTRAIN.



	Between the summer of 1991 and the winter of 1992 we conducted a 

study of the benthic community of southern Lake Pontchartrain to assess 

the impact of New Orleans urban runoff on Lake Pontchartrain. A sampling 

grid, which extended North from the shoreline eight kilometers and 5 

kilometers East to West, was established in southern Lake Pontchartrain 

adjacent to three outfall canals in Jefferson Parish (Parish line, 

Duncan, and  Elmwood canals). Two macrofauna and two meiofauna samples 

were taken from sets of sites within the sampling grid between June 1991 

and February 1992. Differences in species diversity, abundance, 

dominance, and trophic structure among sites were analyzed to assess the 

effect of the outfall canals on the benthic community. 



	Results from our study indicate that there is a pronounced effect 

on the communities immediately adjacent to the outfall canals 

(0m-400m(?)). These sites were characterized by low species diversity 

values, reduced numbers of mollusks (particularly juveniles), and 

increased abundance of nematodes, oligochaetes, and capitellid 

polychaetes on all sampling dates. A transient effect was also seen in 

the meiofauna community following a period of high rainfall.  This short 

term effect extended much further than the chronic effect (2.40 km) and 

was probably a result of the large input of freshwater into the lake. We 

also compared the effects of three different canals, which differed in 

discharge capacity and levels of toxins, on the associated benthic 

communities. A comparison with previous benthos surveys allowed us to 

evaluate the effect of sewage diversion into the Mississippi River, 

initiated in 1989. 







Preston, K.P., Geography/Urban Waste Management and Research Center 

(UWMRC), Poirrier, M.A. and Burns, J.W. Biological Sciences/UWMRC, 

University of New Orleans, New Orleans, LA, COMMUNITY STRUCTURE AND 

DISTRIBUTION OF SUBMERGED AQUATIC VEGETATION IN LAKE PONTCHARTRAIN,LA.



Submerged aquatic vegetation (SAV) generally occurs along the shallow, 

less exposed shoreline areas in the Lake Pontchartrain Basin and 

provides a number of important ecological functions.  Submerged 

grassbeds help stabilize sediments, reduce shoreline erosion, assimilate 

pollutants, and release oxygen.  Moreover, they provide a protected 

habitat for larval and juvenile stages of many estuarine organisms and a 

food source for waterfowl, fish, invertebrates, and other aquatic 

species.  Over the past 40 years several studies have noted a decrease 

in grassbed coverage and a decrease in depth of grassbed growth.  Areal 

coverage of SAV in Lake Pontchartrain has decreased by 50% between 1973 

and 1983.  While previous studies provide general qualitative 

information about the status of grassbeds in Lake Pontchartrain, they 

provide little quantitative information concerning community structure 

and diversity and seasonal variation in growth and distribution.  

Moreover, they fail to take into account the patchy nature of grassbed 

distribution when estimating areal coverage thus likely overestimating 

the actual coverage of SAV beds in Lake Pontchartrain. 



In this study species composition, community structure, and diversity 

relations were determined for five grassbed sites in Lake 

Pontchartrain.  Foliar cover of all SAV species was measured along five 

randomly placed transects in each site during the summer of 1991.  The 

measurements were repeated during the winter of 1992 along a random 

subset of transects at each site.  The seasonal variation in SAV 

distribution and the degree of deciduousness among the dominant species 

could thus be ascertained.  Foliar cover for each species was stratified 

by depth interval and substrate type along each transect in order to 

identify the influence of these physical variables on SAV growth.  In 

addition, the degree of patchiness within grassbeds was used to modify 

estimates of  grassbed coverage in Lake Pontchartrain. 







Rheams, Anne B. Louisiana Department of Environmental Quality, Baton 

Rouge, La., LAKE PONTCHARTRAIN BASIN:URBAN NONPOINT SOURCE POLLUTION 

PROBLEMS AND SOLUTIONS.



	Recent water quality monitoring studies in urban areas have shown 

that the highest pollutant loadings and concentrations usually occur 

during rainfall events in the first 0-1 inch of rain, commonly referred 

to as the "first flush." In urbanizing an area, impervious surface-area 

such as streets, parking lots, and rooftops is increased. These smooth, 

impenetrable surfaces allow little or no detention or infiltration of 

stormwater. As precipitation falls on urban areas, it picks up 

contaminants from the air, littered and dirtied streets and sidewalks; 

petroleum residues from automobiles, exhaust products, heavy metals and 

tar residuals from the roads; chemicals applied for fertilization, weed 

and insect control; and, sediments from construction sites. The dumping 

of chemicals such as used motor oil and antifreeze into storm sewers is 

another source of urban nonpoint source (NPS) pollution.



	Lake Pontchartrain is severly impacted by urban runoff and has been

 targeted as a priority watershed within the Department of Environmental 

Quality's (DEQ) Urban NPS Program. According to the state's 1990 Water 

Quality Inventory (305(b) Report) and the 1991 NPS Assessment Report, 

Lake Pontchartrain ranks second in the state in total water quality 

management subsegments impaired and/or threatened by urban runoff. This 

information is based on evaluative data from the DEQ regional offices 

and specific water quality monitoring stations in the basin.



	In addition to the need for physical, corrective measures such as 

best management practices (BMPs) to prevent and reduce urban NPS 

pollution, source control through public education regarding NPS 

problems and solutions is critical to urban NPS pollutant abatement. 

DEQ's urban NPS public education and involvement strategy includes the 

dissemination of educational materials such as brochures, posters, fact 

sheets, and bumper stickers. DEQ's Storm Drain Stenciling Program has 

been initiated in both Jefferson and Orleans Parishes in an effort to 

alert basin residents of the connection between storm drains and the 

water quality of the lake. The purpose of the stencil program's message 

is to serve as a deterrent to people who dump pollutants such as used 

motor oil down storm sewers, not knowing that the sewers drain directly 

into the lake instead of a wastewater treatment facility. Other 

educational and technical assistance activities include an urban NPS 

video, a model ordinance report, establishment of WATERWATCH groups, and 

a lawn care demonstration project.



	DEQ's Urban NPS Program includes a task for the implementation of 

urban BMPs and the evaluation of their effectiveness in improving water 

quality. DEQ is accepting proposals for BMP projects in priority w

atersheds such as Lake Pontchartrain. 



	While the Urban NPS Program's strategy for implementation is 

non-regulatory, many of the problems related to pollution from urban 

runoff will be addressed through EPA's stormwater regulations. Both 

Orleans and Jefferson Parishes, bordering the south shore of the lake, 

are in the process of applying for stormwater permits.







Rohli, R.V., Southern Regional Climate Center, Department of Geography & 

Anthropology, Louisiana State University, Baton Rouge, LA, DEVIATIONS 

BETWEEN MODELED AND MEASURED RUNOFF IN THE LAKE PONTCHARTRAIN BASIN.



A Thornthwaite monthly water-budget model is used to estimate monthly 

surface runoff into the Lake Pontchartrain Basin from the Comite, Amite, 

Tickfaw, Natalbany, Tangipahoa, and Tchefuncte Rivers for the last fifty 

years.  The modeled outputs for each drainage basin are compared to 

measured monthly runoff data obtained from the U.S. Geological Survey 

for the same time periods.  Statistical tests are implemented to 

identify those basins where seasonal and annual ratios of modeled to 

measured runoff differ significantly from each other.  Hypotheses about 

the differences are developed, and model adjustments are recommended for 

better estimation of runoff from ungaged areas of the Pontchartrain Basin.







Sabate', R.W., The San'Doil Co., New Orleans; Dewailly, E.L., Lumitox 

Gulf, New Orleans; Stiffey, A.V., University of New Orleans:  ALGAL 

BIOLUMINESCENCE IN TOXICITY TESTING



Environmental quality commonly is determined by bioassays, which measure 

the response (primarily death rate) of living organisms to the presence 

of toxins.  Subject organisms range from indigenous populations to 

selected species with demonstrated standard responses, predominantly 

minnows and shrimp.  Cumbersome culture facilities and laboratory 

techniques, which translate to time and expense, together with the 

desire for on-site testing, has led to experimentation with monocellular 

species.  These offer the added statistical advantage of larger numbers 

(thousands or hundreds vs tens) of individuals in a sample aliquot.



Lumitox (R) is a new, compact, fast (hours vs days) patented bioassay 

that uses the marine bioluminescent dinoflagellate alga Pyrocystis 

lunula.  When agitated, P. lunula generates a brilliant flash of light.  

In the presence of varying concentrations of toxins, this light  -  as 

measured by a patented photometer  -  is quenched in a predictable 

manner.  The procedure is very sensitive to small changes in toxic 

concentrations both at high and low levels, is repeatable with low 

variation, and is effective in turbid or colored media.



The U.S. Navy inventor of Lumitox (R) has demonstrated its testing 

efficacy with many substances, including pesticides, defoliants, marine 

antifouling paint, waterbottom samples, and oil-well drilling fluids, 

the latter confirmed by Louisiana State University.  In conjunction with 

University of New Orleans, Lumitox (R) will engage in environmental 

testing and develop a portable testing unit.







Smith, Sue K., Louisiana State University, Baton Rouge, La., NORTH-SHORE 

SOURCES OF SUSPENDED SEDIMENT IN THE SURFACE RUNOFF TO LAKE PONTCHARTRAIN.



	The Lake Pontchartrain Basin in southeast Louisiana comprises 

Lakes Pontchartrain and Maurepas, along with the surrounding land area.  

The major north-shore streams that contribute fresh water into the basin 

are the Amite, Tickfaw, Tangipahoa, and Tchefuncte river systems, along 

with their tributaries.  These streams head in southern Mississippi and 

flow southward across a series of down-stepping terraces through a 

region that is used mostly for agriculture and forestry.  Hydrologic 

data are available for approximately 50 years for these streams.  The 

data show some variations in stage, discharge, and water quality.  

Suspended sediment data show distinct differences between the seasons of 

the year and between the different rivers.  During this time period, 

some of the streams have also shown some changes in their planform 

dimensions.  The nature of these variations and changes are discussed, 

and some possible explanations are offered. 







Thiyagarajah, A., and Ledet, M. J., college of Pharmacy, Xavier 

University of Louisiana, 7325 Palmetto Street, New Orleans, LA  

HISTOPATHOLOGICAL ASSESSMENT OF TWO SPECIES OF FISH FROM THE BAYOU 

TREPAGNIER.



Bayou Trepagnier is located in the Lake Pontchartrain Basin, in St. 

Charles Parish of Louisiana.  Bayou Trepagnier receives treated 

wastewater and storm water from an oil refinery and manufacturing 

complex.  According to the Water Pollution Control Division of the 

Louisiana Department of Environmental quality reports, benzene, toluene, 

ethylbenzene, dichlorobenzene and chloroform were detected in fish and 

crabs collected from the lower stations on Bayou Trepagnier.  Benzene is 

classified by USEPA as a known human carcinogen.  The purpose of this 

preliminary study is to assess the fish health histologically.  We 

selected mollies (Poecilia latipinna) and sheepshead minnows (Cyprinodon 

yariegatus) as test organisms because these species are very sensitive 

to carcinogens.  Fish were caught by beach seine twice in November, 

1991.  Fish were examined grossly, and then processed for histological 

assessment.  Preliminary observations indicate that the majority of the 

lesions are present in the cartilage, muscle, liver, and pancreas.  

Liver lesions range from fatty change to precancerous lesions.  The 

preneoplastic lesions include basophilic cell foci, vacuolated cell 

foci, clear cell foci, and spongiosis hepatis.  Other lesions include, 

fatty change in the exocrine pancreas, fat necrosis, vasculitis, 

protozoan and metazoan parasites in various tissues, and inflammatory 

lesions.  These lesions will be  described and discussed.







Thompson, Bruce A., Coastal Fisheries Institute, Louisiana State 

University, Baton Rouge, Louisiana 70803-7503, A REVIEW OF FISH STUDIES 

ON LAKE PONTCHARTRAIN.



Many questions have been asked over the years about the fish assemblages 

of Lake Pontchartrain.  The members of this 130 species assemblage play 

important roles in both the ecology and economics of the region.  Over 

the past 40 years there have been four major, multi-gear, year-long 

studies of the fishes of Lake Pontchartrain; two in the 50's, and two in 

the 70's.  The last fish survey was done during 1978, 14 years ago!  The 

relative abundance of many common fish species in the lake has changed 

little between 1953 and 1978 and no change in the community proportion 

of marine, estuarine or freshwater fishes was found.  The lake serves a 

major function as nursery and feeding grounds for large numbers of 

juvenile fishes.  Certain environmental changes may be impacting the 

lake's ability to continue to function as a major nursery.  The salinity 

regime of the lake, controlled primarily by riverflow, seems to control 

which fish species will be dominant.  Overall, the fish assemblage 

appears to have a "healthy" indication of seasonal change and a lack of 

overdominance as found in more disturbed estuarine systems.







Thomson, A., University of New Orleans, New Orleans, La., and LeBlanc, 

R.J., Sr., Rufe LeBlanc School of Clastic Sediments, Houston, Tx., 

GEOLOGICAL HISTORY OF LAKE PONTCHARTRAIN.



The Lake Pontchartrain Basin of southeastern Louisiana lies between the 

Late Pleistocene Prairie Terrace to the north and the Late Holocene 

Mississippi Deltaic Plain Complex to the south, a distance of about 28 

miles.  The western margin of the Basin is near the present Mississippi 

River southeast of Baton Rouge, and the eastern margin of the Basin is 

near the western end of the Mississippi Sound.  Thus, the width of the 

Basin is about 90 miles.



Lake Pontchartrain is the largest lake within the Basin.  It has an 

areal extent of about 700 square miles and lies to the east of Lake 

Maurepas and the west of Lake Borgne.  The areal extent of these three 

lakes comprises more than half of the Basin.



Considerable research on the geology of the Pontchartrain Basin was 

conducted over a period of over 40 yrs (1935-1977) by several Louisiana 

State University Geology professors and their graduate students and 

former students, with funds provided by the Corps of Engineers and 

several oil companies.  None of this research has produced any evidence 

that the area encompassed by Lake Pontchartrain was once an extensive 

deltaic plain.



Research results indicate the origin of the Pontchartrain Basin was 

different from the origin of Lake Pontchartrain within the Basin.  

Sub-regional tectonic processes (faulting and subsidence) were mainly 

responsible for the development of the Basin.  In contrast, Lake 

Pontchartrain originated as a result of sedimentation processes.  After 

the last rise in sea level reached its present stand about 5000 years 

ago an arm or embayment of the Gulf of Mexico extended inland as far 

north as the latitude of Mandeville, La.  Later the western portion of 

the embayment was isolated from the Gulf by arms of the Cocodrie and St. 

Bernard Deltas of the Mississippi River, producing Lakes Maurepas and 

Pontchartrain.  Thus, in spite of subsidence and some down-faulting 

within the embayment, the Mississippi River overwhelmed the region with 

sediments, and Lake Pontchartrain remains isolated from the Gulf, with 

the exception of the narrow Rigolets outlet into Lake Borgne.  After the 

St. Bernard Delta was abandoned, the trunk course of the present 

Mississippi River contributed little sediment to the lake.



In conclusion, it is highly probable that faulting within the 

Pontchartrain Basin (south of the Pleistocene Terrace) has played a 

minor role in the origin and development of the lake, but there is 

overwhelming evidence that Lake Pontchartrain was created as  a result 

of Mississippi River diversion and sedimentation.







Turbeville, J.H.Jr., Conoco Inc., New Orleans, La., THE GEOLOGY AND 

GEOHYDROLOGY OF AN AREA REPRESENTATIVE OF NEAR SURFACE AQUIFER SYSTEMS 

ON THE MISSISSIPPI RIVER FLOOD PLAIN IN SOUTH LOUISIANA.



	   		 	       

The Mississippi River Flood Plain is approximately 100 miles wide, 

extending from Lake Pontchartrain to Lafayette, and traversing the 

entire state of Louisiana from north to south.  The near surface aquifer 

system created on the floodplain coincides with both the most heavily 

industrialized and environmentally sensitive areas in the state.  This 

includes the great majority of Lake Pontchartrain and wetland areas.



The study area is located outside of Luling, Louisiana, between the 

cities of New Orleans and Baton Rouge.  It is 1/2 mile south of the 

Mississippi River and 10 miles southwest of Lake Pontchartrain.  Located 

on an industrial park, the area encompasses two separate sources of 

known dichloroethane contamination (a dense non-aqueous phase liquid or 

DNAPL), the Ethylene Maleic Anhydrite (EMA) and Deep Well Pond sites.  

There were 23 wells used in the study that penetrate four stratigraphic 

layers.  Layers I and III are considered to be aquitards, layers II and 

IV are aquifer sands.  The aquifer system interval ranges from 2' to 40' 

measured from ground surface.



Stratigraphic correlations of the aquifer system were completed by 

constructing a series of cross-sections (10) across the area.  A total 

of 7 geologic maps were then generated on the base, top and thickness of 

each aquifer unit.  A hydraulic gradient map was constructed, and 

coupled with hydraulic conductivities (from slug tests), average linear 

velocities of groundwater were calculated.



The penetrated stratigraphy is from Holocene to Recent in age and 

consists of 4 units.  Layers I and III are organic rich clays deposited 

as part of the natural levee system.  Layers II and IV are silt to 

coarse grained sands in fining upward sequences deposited as overbank or 

swale fill that vary in proximity and source direction from the 

Mississippi (or paleo Mississippi) River.  Maximum vertical relief is 

created on the flood plain from the natural levee systems, which 

vertically accrete until the river overruns the levee and eventually 

abandons the channel.



Both layers II and IV are partially confined aquifers that are 

moderately heterogeneous with respect to hydraulic conductivity.  

Hydraulic conductivity values are relatively low and range from .1 to 3 

ft/day, increasing to the south and in the basal portions of layers II 

and IV.  Groundwater flow direction averages southwest, with a hydraulic 

gradient averaging .0036.  The Mississippi River is thought to be a head 

boundary that fluctuates with the rivers stage.



Groundwater velocity is relatively slow with a calculated range from 

.001 ft/day to .04 ft/day, increasing to the south of the study area.  

This is considerably slower than what is observed in areas of known 

contamination in the EMA and Deep Well Pond areas.  Contaminant 

dispersion (spreading out) appears to be a significant factor based upon 

contaminant plume delineation from soil vapor analysis relative to known 

source area.



There is potential for DNAPL contamination to follow the structural base 

of layers II and IV, thereby retarding or accelerating migration 

velocity,  depending on its directional relationship to groundwater 

flow.  Sharp basal contacts created from fining up sequences in both 

layers enhance this effect.





Vega, A. J.,  Southern Regional Climate Center, Department of Geography 

& Anthropology, Louisiana State University, Baton Rouge, LA, 70803,  

LONG-TERM CLIMATIC VARIABILITY OF MODELED AND MEASURED RUNOFF WITHIN THE 

LAKE PONTCHARTRAIN BASIN.



This study examines long term climatic variability of modeled and 

measured runoff within the Lake Pontchartrain Basin.  Runoff estimates 

will be determined using a Thornthwaite water-budget model for the 

Comite, Amite, Tickfaw, Natalbany, Tangipahoa and Tchefuncte Rivers.  

Time series analysis will be employed to determine yearly, seasonal and 

monthly climatic trends in association with individual water years 

(October to September).  Long-term trends will be accessed for each of 

the drainage basins and collectively to determine patterns of climate 

variability (i.e. wet or dry months, seasons, years).  This analysis 

will determine associations between the frequency of extreme temporal 

precipitation events and global circulation variability.     







Wee, James L., Booth, Dennis J. and Bossier, Michael A.,  Department of 

Biological Sciences,  Loyola University, New Orleans, Louisiana,  

Synurophycean Algae from the Lake Pontchartrain region: A Preliminary 

Survey from the Southern Atlantic Coastal Plain of North America. 



	Forty-three taxa of Synurophyceae were identified by means of 

transmission electron microscopy from 10 samples collected in 

southeastern Louisiana, USA, on the southern portion of the Atlantic 

Coastal Plain Province of North America.  Mallomonas prora and Synura 

australiensis  are reported for the first time from North America.  

Samples were collected during a one month time period when water 

temperatures ranged from 15.5-24.5 C.  Sample pH values ranged from 

4.42-7.21.  Notable scale morphology variation was described for some 

taxa.  The flora included three warm water taxa but was dominated by 

temperate and cosmopolitan taxa.  Comparisons with related studies from 

New World, subtropical regions in Florida, USA, and Argentina, were 

made, and significant North American range expansions were noted.  The 

large number of aquatic habitats, 7-8 consecutive months at temperatures 

(6-20 C) best suited for development of synurophyte populations, and 

proximity to major bird migrations routes are postulated as explanations 

for the large number of reported species.