A HYDROLOGICAL, CHEMICAL, AND BIOLOGICAL ASSESSMENT OF
BAYOU AUX CARPES, NEW ORLEANS, LOUISIANA
JANUARY 198 5
by
Environmental Protection Agency
Environmental Services Division
Ecological Support Branch
Athens, Georgia 30613
¦ f
UNITED STATES
ENVIRONMENTAL PROTECTION AGENCY
SCIENCE AND ECOSYSTEM SUPPORT DIVISION
REGION 4
vvEPA
THOMAS R. CAVINDER, P.E.
980 COLLEGE STATION RD
ATHENS, GA 30605-2720
CAVINDER.TOMOEPAMAIL.EPA.GOV
(706) 355-8719
FAX (706) 355-8726
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TABLE OF CONTENTS
Page No.
LIST OF TABLES ii
LIST OF FIGURES . iii
PROJECT PERSONNEL . v
SUMMARY AND CONCLUSIONS 1
INTRODUCTION 4
PROJECT AREA AND STUDY SITE 6
METHODS AND RESULTS 7
Quality Assurance 7
Hydrographic Assessment 7
Water Level Responses . . 8
Ground Surface Elevations . 10
Water Circulation 11
Water Chemistry . . 13
Sediments 15
Biological 17
Swamp and Marsh Biota . 18
Canal Biota 19
DISCUSSION ...... 20
LITERATURE CITED - . . 30
APPENDIX A
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LIST OF TABLES
Table Description Page No,
1 Station Descriptions, Bayou Aux Carpes
Study, January 1985 32
2 Water Level Summary, Barataria Waterway 34
3 Ground and Water Surface Elevations,
Bayou Aux Carpes, January 1985 35
4 Water Chemistry-Chlorides and Salinity,
Bayou Aux Carpes, January 1985 36
5 Water Chemistry, Bayou Aux Carpes,
January 1985 37
6 Sediment Pesticides, Bayou Aux Carpes,
January 1985 39
7 Benthic Macroinvertebrates, Qualitative
Collections, Bayou Aux Carpes, January
1985 .40
8 Fish Collections, Bayou Aux Carpes,
January 1985 41
ii
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1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
LIST OF FIGURES
Description Page No,
Site Location 42
Bayou Aux Carpes, Jefferson Parish,
Louisiana 43
Hydrographic Monitoring Locations, Bayou
Aux Carpes, January 1985 44
Station Location, Nutrient Sampling,
Bayou Aux Carpes, January 1985 45
Station Location, Biological Sampling,
Bayou Aux Carpes, January 1985 46
Water Levels, Bayou Aux Carpes, January
16-20, 1985 47
Daily Water Level Recordings, COE at Algiers
and Barataria Staging Stations, 1984, Bayou
Aux Carpes 48
Wind Speed and Direction, Moisant 49
International Airport, January 1985
Rainfall, Bayou Aux Carpes, January 1985 50
Water Level, East Borrow Ditch, Lafitte-
Larose Highway, Bayou Aux Carpes, January
1985 51
Water Level Comparison, 1/16/85, Bayou Aux
Carpes, January 1985 52
Ground Surface Transects, Bayou Aux Carpes,
January 1985 53
Frequency of Daily Water Levels (1984) at
COE Algiers and Barataria Staging Stations,
Bayou Aux Carpes 54
Water Levels, Chlorides and Dye Tracer,
SNGPL Canal at Junction with ICW, Bayou
Aux Carpes 55
Dye Tracer Study, Bayou Aux Carpes, January
1985 56
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16
17
18
19
20
21
22
23
24
25
LIST OF FIGURES (Continued)
Pescription Page No,
Water Levels, TOC and Total Organic Nitrogen,
SNGPL Canal at Junction with ICW, Bayou
Aux Carpes 57
Water Levels and Nitrogen Forms, SNGPL
Canal at Junction with ICW, Bayou Aux
Carpes 58
NO2-NO3, Organic.N , TOC Comparison,
Bayou Aux Carpes, January 1985 59
Sediment Size Composition, Canals and
ICW, Bayou Aux Carpes 60
Sediment Size Composition, Forested
Swamp and Marsh, Bayou Aux Carpes,
. Stations 2 and 10a 61
Sediment Size Composition, Forested
Swamp and Marsh, Stations 7 and 8,
Bayou Aux Carpes 62
Sediment Metals, Bayou Aux Carpes 63
Seasonal Distribution, Water Levels at
Barataria, Jan - Dec, 1984 64
Seasonal Distribution, Water Levels and
Predominant Winds, Barataria, Jan - Dec,
1984 65
Seasonal Distribution, Water Levels,
Rainfall and Wind Direction, Barataria,
Jan- - Dec, 1984 66
IV
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PROJECT PERSONNEL
*Delbert B. Hicks - Aquatic Biologist, Region IV, EPA
Thomas R. Cavinder - Environmental Engineer, Region IV, EPA
Hoke S. Howard - Aquatic Biologist, Region IV, EPA
Donald W. Lawhorn - Engineering Technician, Region IV, EPA
Barbara Keeler - Biologist, Region VI, EPA
Project personnel wish to acknowledge the assistance of Sue
Hawes, New Orleans District of U. S. Army Corps of Engineers,
whose familiarity with the site was of great benefit.
*Authors
v
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SUMMARY AND CONCLUSIONS
The Bayou Aux Carpes project area consists of approximately
3000 acres of wetlands comprised mainly of forested swamp
and marshes. Although the project is bound on its perimeter
by levees, the Southern Natural Gas Pipeline (SNGP) canal
provides a direct hydrological connection between the site
and the Barataria Intracoastal Waterway (ICW) and Barataria
Bay. Navigation within the project area is provided by the
SNGP canal, petroleum exploration canal, and bayou.
Wind appears to be the primary force effecting water levels
in the project area and the Barataria Waterway. A diurnal
tide range of 0.3 to 0.4 feet was recorded during the study.
This range appears typical of the upper basin region of the
Barataria Bay system. A rainfall event of 1.4 inches produced
no discernible increase in water levels within the project
waterways.
An average ground surface elevation of 1.24 feet National
Geode-t-ic Vertical Datum (NGVD) was determined from 22 survey
observations within undisturbed swamp and marsn areas of the
project site. During-the study, the average depth of water
inundating the marsh and swamp area was observed to be 0.3
.feet. Surface elevation of the. swamp and marsh water at most
locations exceeded water level, elevations in the Barataria
Waterway-and the SNGP canal.. The relatively flat topography
of the. swamp/marsh areas and the broken berm line flanking a
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majority of adjoining canals enhanced the capacity of the
swamp to detain, store, and slowly release surface water to
downstream systems.
The water storage capacity of the swamp was illustrated in
the present study by the measured cyclic chloride concentra-
tion of swamp water discharged to the Barataria Waterway.
Dye tracer studies confirmed that water transport from Bayou
Aux Carpes to the Barataria Waterway was rapid and directed
towards Barataria Bay. Traced waters exiting the Bayou Aux
Carpes site via the SNGP canal traveled downstream in the
Barataria Waterway a distance of six miles in less than 24
hours.
During 1984, water levels in the Barataria Waterway exceeded
the average swamp/marsh surface elevation of 1.24 feet NGVD
at least 50 percent of the time. Water level elevations in
the Barataria Waterway equaled or exceeded 1.24 feet NGVD
between one and 26 days each month during 1984. The frequenc
at which water levels equaled or exceeded 1.24 feet NGVD were
most pronounced during the period from Hay through October
1984 and appe.ared as -a response to southerly wind directions.
During 1984, the. average annual water level in the Barataria
Waterway was in to 14 percent below the 20-year mean; hence7
the potential for the flooding-of the Bayou Aux Carpes swamp
is greater during an average- water year.
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7. The Bayou Aux Carpes project area is a fresh to weakly
brackish aquatic environment. Surface water salinity of the
swamp drainage ranged from 0.5 to 0.8 ppt with a soil water
salinity measuring 1.5 ppt in a marsh area. Salinity of the
Barataria Waterway was 0.1 ppt. Based upon this salinity
regime, the source of the salinity would ultimately be the
Barataria Bay estuary. Winds from the south during the summer
could drive saline water from the estuary into Bayou Aux
Carpes area where it is stored and metered back into the
estuary during the winter with the assistance of northerly
winds.
3. Sampling of canal habitat yielded 14 taxa of macroinvertebrates
and four species of fish. Three estuarine species were in-
cluded in the catch blue crab, fiddler crab, and bay anchovy.
From the marsh/swamp habitat, 27 taxa of macroinvertebrates
including blue crab and 6 species of fish were collected. Many
of the crustaceans collected are important fish food items
such as juvenile crayfish, grass shrimp, and amphipods.
). With the rise and fall of water levels in tne Bayou Aux Carpes
site., a Jiydr.ological mechanism was. available for the exchange
of nutrients and organic matter with the Barataria Waterway.
Measurements of dye dispersion from the site and nutrient ex-
change at the mouth of SNGP canal confirmed an export mechanism.
The Bayou Aux Carpes area was shown to be a source of organic
carbon and nitrogen (detritus) to the Barataria Waterway which
leads to Barataria Bay.
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10. Water from the Barataria Waterway contains urban runoff from
the New Orleans area which is frequently introduced into the
Bayou Aux Carpes system where the surface water is temporarily
detained. With detention, heavy metals are deposited in the
sediments and inorganic nitrogen (NO2-NO3) is biologically
processed into other compounds including plant and animal matter
which are then subject to export to downstream areas.
11. Results of this study confirm the earlier findings of the 1976
EPA assessment of Bayou Aux Carpes. The 1976 study concluded
that Bayou Aux Carpes is a valuable and viable parcel of swamp
and marsh in terms of production and export of organic matter,
habitat for important fish and shellfish, storage of surface
water, processing of nutrients. Therefore, the project area
remains a functioning component of the Barataria Bay system.
INTRODUCTION
The Regional Administrator of EPA, Region 6, has initiated
a 404(c) action on a wetland tract in Jefferson Parish, Louisiana,
south of -New Orleans. The purpose of this action is to preclude
the loss or alteration of wetlands through the filling and/or
forced drainage of approximately 3000 acres of marsh and forested
swamp in the Bayou Aux Carpes area. The filling and forced drainage
of such areas impairs and destroys several natural functions present-
ly providing public benefits. With-this particular project,.loss
of aquatic habitat for the production of fish, shellfish, fish food
items, primary production, and water storage are some of the primary
issues.
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The Administrator for Region 6 requested personnel of the
Environmental Services Division of Region 4 to assist Region 6
members in evaluating these issues in early 1976. At that time,
a team of aquatic biologists and an environmental engineer assessed
pertinent documents and conducted an inspection of the project
area. This inspection produced findings indicating the value of
the Bayou Aux Carpes swamp in terms of ecological functions.(Ap-
pendix A). In 1984, the Environmental Services Division of Region
4 was requested to conduct a technical study to gather additional
site specific facts regarding the chemical, biological, and physical
character of the Bayou Aux Carpes swamp. The site study, initiated
in mid-January 1985, had the following objectives:
o Determine the kinds of fish, shellfish, and benthic macro-
invertebrates associated with the marshes, forested swamp
areas and adjoining canals.
o Determine the water level dynamics associated with the
Bayou Aux Carpes swamp, adjoining .canals, and the Baratari
waterway (ICW) leading to Barataria Bay.
o Evaluate the-potential nutrient and detrital exchange be-
tween the Bayou Aux Carpes swamp, associated canals, and
Barataria Bay.
o Characterize, the water and sediment duality associated
with the Bayou Aux Carpes swamp and adjoining canals.
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PROJECT AREA AND STUDY SITE
The project area of the Bayou Aux Carpes swamp measures
approximately 3000 acres and is located south of New Orleans,
Louisiana and is part of the Barataria Bay Basin (Figure 1). The
area is irregularly shaped and is bounded to the east by the
Barataria Waterway (ICW) and to the west by the Jean Lafitte
National Park and the "V" levee-canal (Figure 2). The National
Park is hydrologically connected to the Bayou Aux Carpes system
via culverts under the Lafitte-Larose Highway (Day, 1984). Navi-
gation to the interior of the study area is possible by way of
the Southern Natural Gas Pipeline (SNGP) canal which connects
with Bayou Aux Carpes and other canals created for petroleum
exploration efforts.
Based upon inspection of the site by EPA personnel in 1976
and current aerial photography of the area, the Bayou Aux Carpes
project area can be described as a diverse wetland composed of'
forest and shrub swamp, marshes, ponds, and open waterways.
Bald cypress, tupelo-gum, green ash, ana rea mapie are common upper
story vegetation of the swamp while softstem bullrush, bulltongue,
cattail, spikerush, and alliqator-weed are typical of the marsh
regions. Water hyacinth and duckweed characterize the floating
vegetation of the Bayou and dredged canals.
Earlier work by Chabreck (1972 )- indicates that the Bayou Aux
Carpes area to be part of the Barataria Basin tiydrologic unit and
is subject to slight tidal effects. Based upon his -description of
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vegetation and salinity for both surface and soil water, the Bayou
Aux Carpes area appears primarily as a freshwater to intermediately
brackish aquatic system.
Because of restricted accessibility, the present study focused
on the areas of the Bayou Aux Carpes swamp associated with the SNGP
canal and exploration canals. Location of stations for hydrograph-
ical, water quality and biological sampling are shown in Figures 3,
4, and 5, with station descriptions provided in Table 1.
METHODS AND RESULTS
Quality Assurance
Methodology involved in data gathering for this study fol-
lowed EPA, Environmental Services Division Standard Operating Pro-
cedures (SOP) protocol.
Hydrographic Assessment
The hydrographic assessment included the determination of
water level dynamics, water motion, and ground surface elevation.
The study of water level dynamics involved the placement of
Stevens recorders within the project boundaries^ in the east-borrow
ditch of the Lafitte-Larose .Highway, at the mouth of the SNGP canal
and on the ICW at the Lafitte-Larose Highway bridge (Figure 3). Ad-
ditionally, water level records from gauging stations operated by
the U. S. Army Corps of Engineers (COE) at the Algiers Lock, Bara-
taria Waterway at.Lafitte, and Barataria Waterway at Barataria
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(Figure 1) were obtained for the current EPA period of study and
for approximately the previous 20 years.
For the period of study, a recording rain gauge was installed
in the Bayou (Figure 3). Wind direction and speed data for the
study period were obtained from the New Orleans Moisant Internation-
al Airport. Ground surface elevations of the marsh and swamp within
the Bayou Aux Carpes area were determined by differential leveling
between the water surfaces in the waterways and the marsh and swamp,
floor.
Water Level Responses
Water levels recorded in the Bayou Aux Carpes study site,
and at the Algiers Lock (upstream of the site) and at Barataria
(downstream of the site) were compared for the study period of
1/16-20/85 (Figure 6). By inspection, water levels at the three
locations appeared to closely track each other. A small diurnal
tide range of approximately 0.3 foot was evident in each record.
Daily water level recordings for a one year period (January -
December, 1984) were examined for the Barataria and Algiers gauging
stations by comparing simultaneous 0800 hours observations (Figure
7. Mean water levels at the Algiers and Barataria stations were
1.28 and 1.24 feet NGVD (National Geodetic Vertical Datum), re-
spectively. The similarity in water level dynamics was also evident
in records spanning. 17 to 22 years for the COE gauging stations
(Table 2). From Table 2, a mean tidal range of- 0.25 to 0.35 foot
NGVD was derived from the difference, between mean low and mean high
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water levels calculated for the gauging records. The tidal range
of 0.3 foot observed in the EPA study appeared typical of the long
term records. Since tidal ranges are relatively small (about 0.3
foot), the effects of wind and rainfall on water level dynamics
were also considered. Wind effects are particularly significant
in shallow, open water bodies such as those associated with the
Mississippi River estuarine system.
The effects of wind on water levels in the Barataria waterway
and Bayou Aux Carpes were clearly evident during the study. In the
afternoon of 1/16/85 a marked rise in water level occurred with a
corresponding decrease following on 1/20/85 (Figure 6). Wind speed
and direction data provided by the Moisant Internationl Airport,
New Orleans, depicted a relatively strong wind from the south with
gusts to 24 knots on the afternoon of 1/16/85 and a strong wind
from the north with gusts in excess of 30 knots on 1/20/85 (Figure
8). From these data, it is apparent that winds from the south ef-
fected a rise in water levels whereas winds from the north lead to
a decrease in water levels.
During this-same period, a rainfall gauge installed in Bayou
Aux Carpes" recorded a rainfall of 1.4 inches between the hours of
2200 on 1/16/85 and 0500 on 1/17/85 (Figure-9), The effects" of
rainfall on water levels in the Barataria Waterway and Bayou Aux
Carpes were not apparent in the records shown in Figure 6. The
record probably reflects the masking effects of wind. However,
the rainfall effected a sharp rise in the water level recorded at
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the Lafitte-Larose highway borrow ditch (Figure 10, see Figure 3
for recorder location). Since the borrow ditch receives roadside
runoff and drainage from the Jean Lafitte National Historical Park,
the water level increase was probably accentuated by storm runoff,
i.e. water level rise was 0.6 feet following a 1.4 inch rainfall
event. Drainage maps of the Lafitte-Larose Hignway (Louisiana
Department of Transportation) show several culverts under the
highway connecting surface drainage of the Park to the Bayou Aux
Carpes system.
Following the rain event, the water level in the borrow ditch
slowly but steadily decreased. This pattern was unlike water level
records for either the swamp or Barataria Waterway. For example, a
water level recorder stationed , in the swamp approximately 0.25 mile
east of the recorder positioned in the borrow ditch (Figure 3) pro-
vided a water level record similar to the ICW records (Figure 11).
The contrast between the swamp, and borrow ditch hydrographs suggests,
at least during the EPA study period, that water levels in the
ditch were not responding simultaneously to hydrographic conditions
in the Barataria Waterway.
Ground Surface Elevations
As previously reported, water level records for the ICW and
Bayou Aux Carpes were nearly identical (Figures 6 and 7); hence,
the recorded water levels at Algiers Lock and the Barataria gauges
were used to adjust water levels in the Bayou Aux Carpes to NGVD.
Ground surface elevations of the marsh/swamp within Bayou Aux
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Carpes System were determined by differential leveling between
the water surfaces in the canals and the marsh/swamp floor. Loca-
tions of the seven ground surface transects are shown on Figure 12.
A total of 22 elevations were determined within the undisturbed
marsh/swamp floor. Elevations ranged from 0.44 to 1.65 feet with
a mean of 1.24 feet NGVD (Table 3).
The frequency of occurrence of water level elevations in the
Barataria Waterway which can potentially flood into the marsh and
swamp areas were determined for 1984. Water levels recorded each
day at 0800 hours were plotted for the Algiers and Barataria water
level gauges (Figure 13). As shown, the mean elevation of the
marsh and swamp floor (1.24 ft. NGVD) was exceeded at least 50 per-
cent of the time by water levels in the Barataria Waterway. Marsh-
swamp elevations of 0.44 and 1.65 feet NGVD were exceeded 95 and 20
percent of the time by water levels in the waterway, respectively.
Numerous breaks in the levees adjacent to the swamp and marshes
including the unfilled areas at the head of the canals allow surface
water to flow between the wetlands and adjacent waterways. Remnants
of the original Bayou Aux Carpes waterway (Figure 2) was unleveed,
thus allowing surface water to sheet flow to the adjoining wetlands.
During the-study period, depth of surface waters in the swamp averaaed
0.3 foot (Table 3).
Water Circulation (Dye Tracer)
A dye tracer (Rhodamine WT) was released at 1200 hours on
1/17/85 in Bayou Aux Carpes at the rain gauge location (Fiqure 3).
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Dye dispersion from the point of release was monitored by automatic
samplers positioned near the mouth of the SNGP canal (Figure .3).
The samplers were operated for a period of 36 hours with sample
collections programmed at one-hour intervals. Samples were split
with one portion measured with a fluorometer for dye concentrations
and the other returned to the Athens Laboratory (EPA) for chloride
analysis. In addition, a boat mounted flow-through fluorometer was.
used to monitor the travel of traced water within the project's
navigable watercourses and in the Barataria Waterway.
Within 3.5 hours following release, the tracer was found at
Station 10 near the mouth of the SNGP canal (Figure 14). The traced
waters exited from the canal and into the Barataria Waterway on suc-
cessive ebb tides. Dye concentrations increased through the ebbing
phase of the tide. During the flood tide, water from the Barataria
Waterway flooded into the SNGP canal resulting in a decrease in dye
concentrat ions.
The traced waters from Bayou Aux Carpes moved rapidly down-
stream through the SNGP Canal and then into the Barataria Waterway
(Figure 15). The dye path from the point of release tracked pri-
marily to the SNG-P Canal and then south to the Barataria Waterway
and then towards Barataria Bay. Virtually no dye moved in a north-
erly direction along the SNGP canal nor did it disperse.upstream of
Station 6, the.long east-west drill hole canal. The leading edge
of the dye cloud entered the Barataria Waterway within 4.5 hours of
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its release. After 21.5 hours, the traced waters had traveled
downstream in the ICW to the community of Barataria (Figure 1),
a distance of 31,000 feet or nearly 6 miles (Figure 15).
Chloride concentrations responded to tidal phase much in the
manner depicted for the dye (Figure 14). At Station 10 near the
mouth of the SNGP canal, chloride concentrations increased on the
ebbing tide with a decrease occurring on the flooding phase. Swamp
drainage appeared as the source of chlorides during the study period.
Surface water from the Barataria Waterway (Station 11) contained the
lowest chloride concentration of 49 mg/L. Chloride concentrations
for other locations in the project area ranged from 250 to 430 mg/L
(Table 4). Soil water collected from a screened well point driven
to a depth of two feet in the marsh floor (Station 10a) yielded a
chloride concentration of 800 mg/L or about 1.5 ppt salinity. Sur-
face salinity ot the swamp drainage ranged from about 0.5 to 0.8 ppt
(Table 4). As discussed later, the ultimate source of the chlorides
in the swamp drainage is presumably the estuary.
Water Chemistry (Nutrients)
The nutrient exchange regime of surface water exchanging between
the Bayou Aux Carpes swamp and Barataria 'waterway was sampled over a
36-hour period. Automatic samplers were positioned at the mouth of
the SNGP Canal (Station 10) and programmed to collect samples at.
hourly intervals. In addition, surf-ace water-grab samples were col-
lected from the Barataria Waterway and at other sites in the swamp
and adjoining canals (Figure 4). All samples were preserved .and
returned to the Athens Laboratory (EPA) for analyses.
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Organic carbon and organic nitrogen concentrations at the
mouth of the SNGP Canal responded to tidal effects as described for
the dye and chlorides observations. Concentrations increased on
the ebbing tide and then decreased during the flooding phase (Fig-
ure 16). This trend suggests that the Bayou Aux Carpes system is
a source of organic matter to the Barataria Waterway. The NO2-NO3
concentration regime at the mouth of the SNGP canal was reversed
in terms of the tidal effects. Concentrations increased during the
flooding phase and decreased when ebbing tides occurred (Figure 17).
The observed relationship between tidal, organic nutrients and
chloride concentrations indicates that with decreasing water levels
in the IC.W, flow at the mouth of SNGL Canal is driven primarily by
swamp drainage. In contrast, the rising water in the Barataria
Waterway provides the energy to disperse water from the Barataria
Waterway to the canal.
Nutrient concentrations of surface water collected from the
swamp, canals, and Barataria Waterway are shown in Table 5. Con-
centrations for ammonia (NH3) and nitrite-nitrate (NO2-NO3) were
greater i-n the Barataria Waterway than in the swamp or associated
:anals. Concentrations of NO2-NO3 were nearly 23 times greater in
:he Barataria Waterway compared to the marsh-swamp drai-nage (Figure
L8). In contrast, higher level-s of organic carbon (TOC) and organic
litrogen (Org. N) were associated with swamp drainage (Figure 18).
larsh-swamp drainage featured at least a two-fold increase -in.TOC
ind organic nitrogen concentrations compared to Barataria Waterwav
ICW) .
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Sedirfents
Particle size and organic content of sediments are factors
affecting the kinds and numbers of benthic macroinvertebrates
dwelling in or upon the bottom. Bottom sediments also serve as a
sink for many kinds of heavy metals and man-made compounds such as
pesticides. To characterize these physical and chemical aspects,
sediments were obtained from the bottom of selected stations in
forested swamp, marshes, canals, and the Barataria Waterway. Samples
analyzed for particle size, organic content, and heavy metals were
collected as 10 cm bottom cores.
Results for priority pollutant pesticides and PCB analyses of
sediment samples indicate all designated compounds examined were
below the detection limits for the chemical procedure employed
(Table 6).
Particle size composition of core samples from the Barataria
Waterway and canals was predominately silt particles (0.0039 to
0.0625 mm in Figure 19). Total organic content of the core samples
ranged from 12 to 20 percent, by dry weight. The sediment profiles
for Station 2 (a forested swamp area) and Station 10a (a marsh area!
were similar to those characterizing the canals and Barataria Water-
way (Figure 20). Stations 7 and 8 (a marsh and swamp site, respec-
tively) were in sharp contrast to other sites. Sediments were pri-
marily comprised of coarser materials (identified as decomposing
vegetation),"2 to 32 mm, with a total organic content of.64 to 67
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percent (Figure 21). Sediments featuring an organic content exceed-
ing 5D percent by dry weight are generally typical of peat substrate
(Chabreck, 1972). Chabreck further indicates that sediments with
less than 15 percent organic content tend to represent mainly mineral
soils comprised primarily of silt, clay, and sand. Based upon
these distinctions, the sediments (top 10 cm) associated with the
Barataria Waterway and canals appear alluvial in origin. .In this
:ase the silt and clay particles originated elsewhere and were
-.rapped by the stilling effects of the canals and wetlands.
The contrast in sediment profiles for the two swamp or marsh
areas sampled appeared related to their hydrological connection to
:he canals. As indicated by the general station description (Table
.), Stations 2 and 10a were in the direct pathway of surface water
>xchanging between the canals and the wetlands via breaks in the
ierm line. Stations 7 and 8 were not proximate to breaks in the
:anal berm. The surface water exchange between the canals and
zetlands was more characteristic of sheet flow. By the time the
surface water originating from the canals reached the more interior
itesv its silt-load was probably relieved via the deposition pro-
ess.
The ability of canals and the swamp/marsh habitat"to trap
inely divided particles was "also evident in the heavy-metals con-
entrations determined for the sediments (Figure 28). The.ICW
ppeared.to retain greater concentrations of zinc compared"to the
wamp and marsh areas. Copper, lead, and iron, concentrations
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appear uniformly distributed between the swamp, marsh, canal,
and Barataria Waterway (ICW). This distribution pattern indicates
the capacity of the marsh/swamp system to trap these heavy metals
typically associated with urban runoff.
Biolog ical
Qualitative sampling for benthic macroinvertebrates was con-
ducted in Bayou Aux Carpes marsh and forested swamp environs (Sta-
tions 2, 7, 8 and 10a). Various methods, such as standard biologi-
cal dip nets and drift nets (.5 mm mesh) and hand sorting from
available substrates including aquatic plants, stumps, rocks and
debris were employed.
To sample nektonic animals in the canals, a channel net was
stretched across the canal segment leading from the SNGP canal to
Station 4 and anchored to stakes deeply driven into the adjoining
banks. The net was constructed of 1 mm nylon mesh with a 5/16-inch
chain secured to the foot line of the net. It measured 8 x 50. feet
with an 8 x 8 x 8 feet center bag. The canal channel measured ap-
proximately 60 to 70 feet in width, hence, _tne net when in.place
only partially blocked the_ canal. The ne.t was fished for approxi-
mately four hours on an ebbing tide. Specimens collected from the
net were stored in widemouth plastic containers with 90 percent
ethanol as a preservative and returned to the Athens Laboratory for
identification to the lowest possible taxa.
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Swairtp and Marsh Biota
Sampling of benthic macroinvertebrates indicated a relatively
low level of species richness associated with the swamp and marsh
habitat (Table 7). Crustaceans and odonates appeared as the
predominate groups of taxa observed in the samples. Nine and 14
taxa of macroinvertebrates were found associated with the swamp
areas sampled at Stations 2 and 7, respectively. Five of these
taxa were common to both stations which included two kinds of
amphipods, aquatic snails, and juvenile crayfish. Aside from the
difference in number of taxa (9 versus 14), hydrology and substrate
quality were also different.
Station 7, when compared to Station 2, was more of an interior
site in the swamp where the water was deeper (3 to 4 inches) and
its movement characteristic of sheet flow. Station 2 was character-
ized by a more vigorous flow regime because of its closer proximity
to a primary surface water connection between the canal and swamp.
The sediment of the interior swamp site (Station 7) was character-
ized as peat substrate compared to a more finely divided substrate
of silt and sand at -Station 2.
Samples frora two marsh sites (Stations 8 and 10a) -each yielded
nine taxa of benthic macroinvertebrates (Table 7). As in the case
of the two swamp stations sampled, the quality, of substrate and sur-
face water movement were also distinctly different. Three species
of amphipods and one species of snail were common to both marsh
areas. Grass shrimp, P. kadiakensis, and blue crab, C. sapidies.
-------
-19-
were found associated with the small drainage cuts extending from
the SNGP canal into the marsh at Station 10a. The presence of blue
crabs, a juvenile specimen, reflects the hydrological and biological
interaction between the project area and the estuary.
In addition to the benthic macroinvertebrates collected in the
swamp and marsh habitat, several species of fish were found associ-
ated with these areas (Table 8). Livebearers, such as mosquitofish,
least killifish, and sailfin molly, were observed. Mosquitofish
appeared as the most abundant species. In addition, spotted sunfish,
banded pygmy sunfish, and one species of killifish were collected.
Except possibly for the banded topminnow, the fish collected are
considered euryhaline species with mosquitofish being common to
tidal swamps and marshes (Odum, 1984).
Canal Biota
Sampling of canal biota was limited to a single blocknet set.
Because the net only partially blocked the canal channel, the data
collected by this means must be viewed in qualitative terms.
The blocknet catch yielded 14 taxa of macroinvertebrates and 4
taxa of fish (Tables 7 and 8). Eight invertebrate taxa were common
to the macroinvertebrate communities associated.with the marsh and
swamp environment. In addition to the blue crab, a second estuarine
crab (Uca sp.) was captured by the channel net.
The fish species were represented by juvenile specimens and
included bay anchovey, gizzard snad, sunfish, and least killifish
-------
-20-
(Table 8). The bay anchovy is an estuarine species which generally
migrates to tidal freshwater in the early spring to feed and then
returns to the estuary to spawn in late spring. Larvae of this
species move upstream to weakly brackish and freshwater tidal nur-
sery areas in the summer (Odum, 1984).
DISCUSSION
Presently, levees span virtually the entire perimeter of the
Bayou Aux Carpes project area. The Southern Natural Gas Pipeline
(SNGP) canal provides the primary hydrological connection between
the swamp and the Barataria Waterway (ICW) and ultimately Barataria
Bay. With construction and maintenance of the SNGP canal and asso-
ciated drill hole canals, dredged materials were spoiled along the
canal banks thus forming berms which in some areas measured several
feet high. Numerous breaks in the berm line, especially at the end
of the canals, provide a pathway for surface water to exchange be-
tween the swamp marshes and canals. Determining the potential for
exchange of water between these systems was one of the primary
objectives of the hydrological assessment.
The mean water level for the Barataria Waterway in the vicinity
of the project area was 1.38 to 1.45 feet- NGVD. Ground" surface ele-
vations of swamp and marsh areas surveyed" averaged 1.24 .feet NGVD.
Accordingly, the potential for the flooding of the Bayou Aux Carpes
by rising water in the Barataria Waterway appears to occur at least
50 percent of the time (Figure 13). Furthermore, the frequency of
water levels at or above 1.24 feet NGVD in the Barataria Waterway
appeared strongly seasonal (Figure 23).
-------
-21-
The 1984 water level record for the Barataria Waterway (ICW)
reveals three aspects of the flooding regime. First, the 1984
record depicts the average monthly water level as generally peaking
during the period of May through October. Since the average ground
elevation of the Bayou Aux Carpes swamp was 1.24 feet NGVD, water
stages attaining or exceeding this elevation could initiate flood-
ing of the swamp. It is only coincidental that the annual monthly
water levels in 1984 averaged 1.24 feet, which is identical to the
average surface elevation of the swamp in the study area transects.
Secondly, the 1984 annual water level average of 1.24 feet NGVD in
the Barataria Waterway was about 0.14 to 0.21 of a foot less than
the 20-year average reported in Table 2, i.e., about 10 to 14 per-
cent less in amplitude than the 20-year average. Finally, the
lower graph in Figure 23 shows that flooding of the swamp could
have occurred in each month of the 1984 water year and possibly
even daily as suggested in the case of October during an average
or above average water year.
The primary factor controlling the water level appeared to be
wind. Short term effects of wind were clearly apparent during this
study. Winds from the south increased water levels; whereas, winds
j-lvjui Lne nurtn etreccea a measurea decrease in water levels (Figures
6 ana 8).
Historically, winds from the south prevail during the summer
while winds from the north dominate during the winter (Figure 24).
Rain events do not appear to effect water levels as.readily as the
wind (Figure 25). As indicated by Day (1984), winds from the south
-------
-22-
provide the necessary energy to drive estuarine waters into the
Bayou Aux Carpes region of the Barataria Basin, which would account
for the weakly brackish character of the waters draining from the
swamp during this study. The capacity of the Bayou Aux Carpes
swamp to detain surface waters was evident in the chloride data
reported for this study. Chloride concentrations increased with
ebb flows from the swamp and decreased when the direction of flow
reversed and originated from the Barataria Waterway (Figure 14).
The relatively flat topography of the swamp, in combination
with the broken berm line of the canals, undoubtedly served as
factors enhancing the capacity of the swamp to detain surface waters
ancT~effect^Tts^Tlow release"~to downstream systems. The average
depth of water over the swamp and marsh floor was 0.3 foot (Table
3). This value when added to the average ground surface elevation
of the swamp resulted in an average water level elevation of 1.54
feet NGVD. This elevation was above the maximum water level height
recorded in the ICW and study canals (Figure 6). The water stored
in the forested swamp would seek breaks in the berm line where it's
gradually discharged into the canals and ICW. Such a hydraulic
gradient would explain the observed net movement of organic carbon,
organic - ni t-rogen , chlorides, and. dye to the Barataria Waterway.
The seasonal flooding and storage regime of the Bayou Aux
Carpes area provides numerous and unique benefits in terms' of
nutrient processing, primary and secondary production, flood con-
trol, salinity control, and as a nursery habitat for. freshwater and
estuarine fish and shellfish.
-------
-23-
The hydrological connection between Bayou Aux Carpes and the
Barataria Waterway and the capacity of the Bayou system to detain
surface water combined to buffer effects of urban runoff from the
New Orleans area on downstream regions like Barataria Bay. Results
of. the sediment analyses demonstrate the function of Bayou Aux
Carpes as a mechanism for trapping finely divided materials thus
interrupting their transport to the estuary. Heavy metals, whether
absorbed to silt, clays, organic matter, or precipitated as metallic
sulfides, are deposited in the sediments.
By detaining the surface water particularly associated with
summer flooding, nutrient cycling in the swamp is enhanced. Deten-
tion increases the contact time of overflow water with the forest
floor of the swamp which is the principal site of denitrification
processes and nutrient uptake by rooted vegetation (Brinson, 1981).
The timing of the annual flooding regime coincides with the primary
growth period of the swamp plant community in southern Louisiana
freshwater swamps (Conner and Day, 1976).
The denitrification process (NO2-NO3 to N2) is an efficient,
rapid, and important function in forested swamps as. well as tidal
parshe.s (Brinson, 19&1;_ EPA,_ 1984; and Brinson, ej: j^. , 1984) .
Denitrification is an anaerobic process involving specialized
bacteria which utilize the nitrogen bound oxygen {NO3) as an energy
source. In this manner, the NO3 is reduced to nitrogen gas (N2) as
:he bacteria assimilate organic matter. Thus, the decomposition of
organic matter proceeds in the absence of dissolved oxygen and the
-------
-24-
nitrite-nitrate load of the overflow water is diminished. At vir-
tually all marsh and swamp stations sampled, disturbed sediments
yielded the odor of hydrogen sulfide, which is characteristic of
a reducing environment.
The biological cycling of inorganic nitrogen (NO2-NO3) was
evident in the Bayou Aux Carpes swamp. The NO2-NO3 concentration
gradient decreased from sampling points in the Barataria Waterway
to stations in the forested swamp and marshes (Figure 18). In this
context, the Barataria Waterway emerges as a primary source of
NO2-NO3 and the Bayou Aux Carpes swamp a principal area for its
assimilation into other nitrogen forms such as animal or plant
protein. Accordingly, the elevated concentrations of organic nitro-
gen in the swamp drainages as compared to those in the Barataria
Waterway is not surprising (Figure 18).
With the rise and fall of water levels in the swamp, a hydro- .
logical mechanism is established for the exchange of nutrients
between the swamp and Barataria Waterway. The export of these
materials can be frequent (Figure 23). The lower graph of Figure
29 indicates the number of days each month in 1984 when the water
level in the ICW equaled or exceeded the average ground elevation
of the swamp and marsh. For each day that the water level in the
ICW falls below 1.24 feet NGVD, a net drainage of surface water
from the swamp to the Barataria Waterway is possible as demonstrated
in this study. Results of the dye dispersion measurements confirmed
the net movement of surface waters was from the Bavou Aux rarnes
-------
-25-
swamp to the Barataria Waterway and downstream towards the estuary.
Although the exchange of organic matter between the swamp and
Barataria Waterway was not quantified in terms of loadings (tons/
year), net export of organic nitrogen and total organic carbon
(TOC) from the Bayou to the Barataria Waterway was.evident. Con-
centration of dye, chlorides, organic nitrogen, and TOC increased
at the mouth of the SNGP canal during the ebb phase of the tide
(Figures 14, 16, and 17). The concentration gradient depicted in
Figure 18 for TOC and organic nitrogen indicates the swamp and
marshes as the principal source of organic matter in the export
reg ime.
In terms of annual export of organic carbon and nitrogen from
a forest swamp such as Bayou Aux Carpes, the work of Day, et al.
(1977) provides a Doint of reference for judging the potential of
the export regime in terms of mass loading from forested wetlands.
These investigators conducted a 14-month study of net production
and export of nutrients from a swamp forest in the upper drainage
basin of the Barataria Bay estuary. Annually, the 770 km2 swamp
exported"8016, 1047, and 154 metric tons of organic carbon, nitro-
genT and phosphorus, respectively, to the estuary. The hydrological
regime of tne swamp studied by Day, et £l_. ( 1977) was somewhat dif-
ferent from the Bayou Aux Carpes area. Both were subject to seasonal
flooding; however, rainfall was the principal source of surface
drainage in the swamp studied Dy Day, et al_. ( 1977). For the Bayou
Aux Carpes area, surface water drainage was primarily controlled by
wind; rain and tide were secondary influences.
-------
-26-
A source of organic matter (detritus) for export from the
swamp would be its forest and marsh community of plants. Since the
Bayou Aux Carpes site is a relatively typical cypress-tupelo swamp
in terms of vegetational characteristics and seasonal flooding, its
annual primary production would probably be similar to the swamp
studied by Conner and Day (1976). These authors reported total
primary production for the seasonally flooded Louisiana swamp at
1,574 g/m2/yr at a bottomland hardwood site and 1,140 g/m2/yr at
a cypress-tupelo site. The net primary production in forested
swamps is generally greater in seasonally flooded systems (Brown,
et al., 1979).
The present study demonstrated a hydrological connection be-
tween the Bayou Aux Carpes swamp and the Barataria estuary. The
pathway between the estuary and swamp appears operational each month
of the year at least in the 1984 water year; thus, providing a
route for the exchange of nutrients and aquatic life between the
swamp and estuary.
Day (1984) provides insight to the seasonal migratory patterns
Df fish and shellfish in the Barataria Bay and its associated fresh-
water basins. He identifies the more traditionally reported migra-
:ory patterns of estuarine species using the freshwater.regions of
an estuarine basin as nursery habitat. He documents the presence
)f bay anchovy, sheepshead minnow, spot,, striped mullet', tidewater
jilverside, and lady fish in the vicinity of the Jean Lafitte
National Historical Park which is part of the Bayou Aux Carpes
swamp. Hawes (1984) exDanded this licK nf oeHnfino ^~~ ~ c
-------
-27-
Bayou Aux Carpes to include both juvenile and adult blue crab.
The present study confirmed continual use of the Bayou Aux Carpes
by estuarine species (tables 7 and 8). Juvenile forms of estuarine
crabs and bay anchovies were found in the mid-January sampling.
From Day (1984), Hawes (1984), and the present study, at least
15 species of freshwater fishes are reported to be associated with
the Bayou Aux Carpes drainage area. Many of these species such as
channel and blue catfish, sunfish, and bass, are recognized as im-
portant to both commercial and sport fisheries. Day (1984) further
elaborated on the potential for a number of freshwater species to
seasonally expand their territory in the winter. As he explains
and documents, adult and juvenile forms of some . freshwater species
move from the traditional freshwater regions towards the Gulf in
the fall and early winter where they replace marine species immi-
grating from the estuary to the Gulf. As summer approaches, salinity
and temperature increase and the freshwater forms retreat back to
the upper freshwater zones of the basin. This cycle would appear
particularly significant in terms of assigning a fishery resource
value tothe Bayou Aux Carpes area. The assessment work of Day (1984)
clearly indicates that the potential benefits of fishery production
can extend well beyond the geographical boundaries used to describe
Bayou Aux Carpes.
For the Bayou Aux Carpes project site, the benthic macroinverte-
brate data indicated a relatively restricted community in terms of
species richness (Table 7).. For the two marsh
-------
-28-
site in the forested swamp, only nine taxa were observed. How-
ever, many of the taxa found can tolerate a wide range of environ-
mental conditions including low concentrations of dissolved oxygen
and salinity. For several reasons, the relatively low diversity of
the community is not surprising. As explained by Odum (1984), the
relatively simple structure of the benthic macroinvertebrate com-
munity in a tidal freshwater system can be linked to a lack of
diverse habitat. Non-tidal systems tend to yield a substantially
more diverse community of benthic macroinvertebrates than a tidally
effected system. The chloride data gathered in this study coupled
with the findings of Chabreck (1972), indicate that the Bayou Aux
Carpes site is seasonally brackish which would favor the survival
of euryhaline species and impair the success of pure freshwater
forms. Several of the taxa found in the Bayou Aux Carpes system
can tolerate both fresh and saline environments. Although the
benthic community may be represented by relatively few taxa (a
total of 27), many of the taxa are important processors of organic
matter and fish food items including crayfish, grass shrimp, and
other crustaceans such as amphioods (Hyalella azteca and Gammarus
sp. ) .
In the findings of the 1976 assessment by EPA personnel,
Barataria Bay was described as the singly most productive estuarin
area along the Louisiana coast (Appendix A). Also indicated was
the fact that Louisiana estuaries owe their high level of producti
ity to the ex-tensive system of marshes and swamps of the upper
basins. These upper basin regions of swamps arid marshes provide
-------
-29-
the drainage necessary to maintain the broad, stable brackish zones
in the estuary. The Bayou Aux Carpes system is one of these upper
basin swamps draining to Barataria Bay.
The results of this study corroborate the findings of the EPA
assessment in 1976 and the later assessment by Day (1984). Despite
the present alterations of the swamp, mainly the presence of levees
and canals, the Bayou Aux Carpes area provides local and regional
benefits in terms of water storage and release, habitat for the
production and growth of freshwater and estuarine fish and shell-
fish, nutrient processing, and a source of organic matter for ex-
port to Barataria Bay.
-------
-30-
LITERATURE CITED
Brinson, M. M. , H. D. Bradshaw, and E. S. Kane. 1981. Nitrogen
cycling and assimilative capacity of nitrogen and phosphorus
by riverine wetland forests. Water Resource Research Insti-
tute. Rept. No. 167. University of North Carolina. 90p.
Brinson, M. M., H. D. Bradshaw, and E. S. Kane. 1984. Nutrient
assimilative capacity of an alluval floodplain swamp.
Journal of Applied Ecology. Vol. 21, 1041-1057p.
Brown, S., M. M. Brinson, and A. E. Lugo. 1979. Structure.and
function of reparian wetlands in strategies for production
and management of floodplain wetlands and other riparian
ecosystems. Gen. Tec. Rept. WO-12. U.S. Dept. of Agriculture.
U.S. Forest Service.
Chabreck, R. H. 1972. Vegetation, water, and soil characteristics
of the Louisiana coastal region. Bulletin No. 664. Louisiana
State University. Agricultural Experiment Station. 72p.
Conner, W. H. and J. W. Day, Jr. 1976. Productivity and composition
of a bald cypress-water tupelo site and a bottomland hardwood
site in ' a " Louisiana swamp. Amer. "J." Bot. 63 (1): 1354-1364 .
Day, J. to. , Jr., T. J. Butler, -and toi H. Conner. 1977. Productivity
and nutrient export studies in a cypress swamp and lake system
in Louisiana. I_n Estuarine Processes, M. Vviley,- ed. Vol. 2.
Academia Press..
-------
-31-
Day, J. W. , Jr. 1984. A study of the effects of the proposed
leveeing and drainage of the Bayou Aux Carpes swamp on the
adjacent Barataria Unit, Jean Lafitte National Historical
Park. Report to Jean Lafitte National Historical Park.
Environmental Protection Agency. 1973. Biological Field and
Laboratory Methods for Measuring the Quality of Surface
Waters and Effluents. EPA-670/4-73-001.
Environmental Protection Agency. 1984. Reeves Project: A study
of the intertidal marshes and streams. Rept. EPA, Environ-
mental Services Division. Athens, GA 30613.
Environmental Protection Agency. 1980. Standard Operating Pro-
cedures. Engineering Section. Environmental Services
Division, Athens, Georgia.
Environmental Protection Agency. 1982. Standard Operating Pro-
cedures. Environmental Biology Section. Environmental
Services Division, Athens, Georgia.
Environmental Protection Agency. 1982. Standard Operating Pro-
cedures.^ Laboratory Services. Environmental Services Division,
Athens, Georgia.
Hawes, S. 1984. Memo for the record. COE, New Orleans District.
Odum, W. E. 1984. The ecology of tidal freshwater marshes of the
United States east coast: a community profile. FWS/OBS-83/17.
U.S. Fish and Wildlife Service.. U.S. Dept. Interior.
-------
-32-
Table 1. Station Descriptions, Bayou Aux Carpes Study,
Louisiana, January 1985
Barataria Waterway (ICW):
Station 11 located approximately 100 yards from north
shore in Barataria Waterway; soft, silty substrate; depth
of 12-14 feet.
Canals:
Station 3 mid-channel, located approximately 50 yards from
head of short drill canal; silty substrate; bottom depth of
6-7 feet; hyacinths (Eichornia crassipes) at head of canal;
berm vegetation consisted of red maple (Acer rubrum), mainly
sweetgum (Liquidambar styraciflua) and wax myrtle (Myrica
cerifera).
Station 4 -- mid-channel, about 200 yards north of original
Bayou Aux Carpes waterway; silty substrate; bottom depth of
6 feet; macrophytes along shore consists of a 11igatorweed
(Alternanthera philoxeroides), bulltongue (Sagittaria falcata),
pennywort (Hydrocotyl).
Station 9 Tnid-channel, northernmost station in SNGP canal;
approximately mid-point of canal length; soft, silty sub-
strate; bottom depth of 5-6 feet; berm vegetation consisted
of mainly red maple (Acer rubrum), willow (Sa1i x), sweetgum
(Liquidambar styraciflua) , wax myrtle (Myrica cer i fera),
elderberry (Sambucus).
Station 10 mid-channel, approximately 50 yards upstream
from mouth of SNGP canal; soft, silty substrate; bottom depth
of 4-5 feet; berm vegetation consisted of mainly willow
(Sa1ix), elderberry (Sambucus), water oak (Quercus nigra).
Marsh:
Station 8 Marsh area, open canopied, located off west side -
of SNGP canal (" 1/4 mile from canal mouth); substrate, ap-
peared to be rich in organic matter (decayed and partially
decomposed vegetative material); depth of water overlying
substrate was generally less than one inch; most macrophytic
vegetation was dead at time of study except for some. Hydrocotyl.
Station 10a Marsh area east of Station 10; station has a
break in berm and egress and ingress of water was noted dur-
ing the study period; most marsh vegetation was dead at the
time of the study except for Hydrocotyl; substrate composition
in the drainage cut appeared to be fine organic matter over-
lying fine sand; water depth in the marsh was approximately
1-2 inches while the . drainage cut was aoDrox imatel'v 10-1? inrhpc
-------
-3 3-
Table 1 (Continued)
Forested Swamp:
Station 1 Located in forested swamp 50 yards off
western end of shorter drill canal; station was located
in drainage cut which emptied into the drill canal; flow
between swamp and drill canal was evident during the study;
vegetative community consisted of cypress, water tupelo with
understory of lizard's tail (Saururus cernuus), bulltongue
(Sagittaria falcata), coontail (Ceratophyllum demersum),
water depth of approximately one foot; substrate appeared
to be composed of fine silt overlying fine sand.-
Station 2 -- Located in forested swamp 50 yards off
eastern end of shorter drill canal; station was located
in drainage area which had flow emptying to the drill canal
during the study period; vegetation same as described for
Station 1; water depth was approximately one foot; substrate
appeared to be fine silt overlying fine sand.
Station 5a -- Located in drainage cut at end of longest drill
canal; forested swamp composed of cypress and water tupelo
with an understory of bulltongue, lizard's tail; water depth
was approximately one foot; substrate appeared to be fine
silt and sand.
Station 9a -- Located in forested swamp, east of Station 9
which is approximately one mile from the mouth of the SNGP
canal; vegetation consisted of mainly cypress, water tupelo;
depth of water approximately 3/4 - 1 inch; substrate ap-
peared to be high in organic content, especially decaying
or partially decomposed vegetation.
Station 7 -- Located in forested swamp off west side of SNGP
canal (approximately 1/2 mile from canal mouth); cypress,
water tupelo, red maple were predominant trees; understory
vegetation consisted of bulltongue (Sagittaria falcata) ,
banana lily (Nyrophoides aquatica) and lizard's tail; water
depth of 6 inches, substrate appeared to contain large
amounts of decomposing organic matter.
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-34-
TABLE 2
WATER LEVEL SUMMARY (FT - NGVD)
BARATARIA WATERWAY
ICW at1
Algiers
Lock
Bayou^
Barata ri a
at
Rarataria
Bayou^
Baratari a
at
Laf i tte
Mean Annual Extreme High
Mean High
Mean Annual Extreme Low
Mean Low
Mean Water Level^
Mean Tide Range^
3.07
1.55
-0.10
1.20
1 .38
0.35
2.92
1.57
0.23
1.32
1.45
0.25
2.94
1.60
-0.05
1 .25
1.43
0. 35
Date Source: COS
1 - 1958 through 1980
2 - 1962 through 1980
3 - 19 63 through 198 0
4 - Based upon average of mean high and mean low stage
5 - Based upon difference of mean high and mean low stage
-------
-35-
TABLE 3
GROUND AND WATER SURFACE ELEVATIONS (FT - NGVD)
BAYOU AUX CARPES
JANUARY 1985
Swamp/Marsh Left Swamp/Marsh Right
Transect Ground Water & Ground Water
A 1.53 1.60 d.oi 1.60 1.63 o-
1.27 1.60 e,37 1.65 1.67 ft.
1.61 1". 67
B 1.49 * 1.28
1. 54 1. 59 1.27
C 1.05 1.53 1.02
1.00 1. 54 1.12
D 0.44 0.97 0.'
1.04 "
E 1.32
0.66
F 1.60 1.80 O.IO 1.19
1. 56
G 1.51
0.57 1.4 2 0$t>'
Total of 22 Ground Observations
Maximum 1.65
Mean 1.24
Minimum 0.4 4
'Water level below ground surface
Total of 17 Water Observation
X
Maximum.
Mean
Minimum
£)
1.80
1.54
0.00
a - : 0
Cn ^ ^ *
^ A
-------
-36-
TABLE 4
WATER CHEMISTRY-CHLORIDES (mg/L) and SALINITY (ppt)
BAYOU AUX CARPES
JANUARY 1985
STATION
DATE
TIME
CL
STATION
DATE
TIME
CL
Sal (ppt)
10
1/17
1045
130
2
1/20
1200
250
0.5
1145
140
5
1/23
0800
260
0.5
1345
170
7
1/20
1230
220
0.4
1445
180
9
1/20
0800
430
0.8
1545
190
10a
1/20
1330
300
0.6
1645
210
10 soil
1/19
1535
800
1.5
1745
220
11
1/20
1400
49
0.1 _
1845
240
1945
240
2045
250
2145
210
2245
110
2345
110
1/18
0045
0295
0345
1330
1430
1530
1630
1730
1830
1930
2030
2130
2230
2330
130
70
70
280
290
300
290
220
100
110
250
290
260
150
1/19
0030
0130
0230
0330
. 0430
0530
0630
0730
0830
0930
140
70
54
51
52
54
65
77
130
200
-------
1
1
1
2
2
2
3
3
3
4
4
4
5
5
5
5
5
5
6
6
6
7
7
7
9
9
9
-37-
TABLE 5
WATER CHEMISTRY (mg/L)
BAYOU AUX CARPES
JANUARY 1985
DATE
TIME
nh3-n
NO2-NO3-N
Org. N
T-P
TOC
1/17
1100
0.22
<0.05
0.78
0.11
14
1/18
1205
0.33
<0.05
0.87
0.11
14
1/19
1415
0.50
<0.05
0.90
0.14
17
1/17
1100
0.07
<0.05
0.93
0.10
12
1/18
1210
0.16
<0.05
0.79
0.10
15
1/19
1410
0.37
<0.05
1.23
0.15
19
1/17
1115
0.50
0.76
0.50
0.36
11
1/18
1200
0.26
0.65
0.72
0.34
12
1/19
1405
0.24
0.57
0.68
0.34
12
1/17
1120
0.20
0.94
1.00
0.38
11
1/18
1155
0.26
0.35
0.84
0.37
15
1/19
1400
0.14
0.25
0.84
0.36
14
1/17
1640
0.18
<0.05
0.60
0.22
15
1/18
1135
<0.05
<0.05
0.80
0.16
14
1/19
1420
0.09
<0.05
0.76
0.20
15
1/17
1135
<0.05
<0.05
0.72
0.14
14
1/18
1135
0.12
<0.05
0.80
0.14
14
1/19
1430
0.55
<0.05
0.25
0.18
15
1/17
1206
0.14
0.35
0.96
0.34
15
1/18
1150
0.18
0.16
0.82
0.33
15
1/19
1500
0.09
0.24
0.90
0.33
14
1/17
1315
0.12
<0.05
3.58
0.37
44
1/18
1230
0.12
<0.05
1.58
0.14
22
1/19
1335
0.08
<0.05
0.92
0.13
21
1/17
1300
0.23
0.24
1.07
0.30
15
.1/18
1215
0.22
0.14
1.08
0.20
21
1/19
1350
0.19
0.09
0.91
0.18
18
1/17
1330
0.20
<0.05
1.20
0.64
11
1/18
1315
0.08
<0.05
1.-12
0.50
13 .
1/19
1300
0.10
<0.05
0.40
. 0.26
12
1/17
1330
0.62
1.4
0.48
0.56
8.
1/18
1320
0.63
.1.4
0.17
0.56
8.
-------
TOC
14
12
11
12
13
13
14
13
12
11
10
9
8.
8.
9
12
14
11.
16
15
17
23
16
14
11
8.
14
16
14
-38-
TABLE 5 (continued)
NO2-NO3-N
0.19
0.19
0.19
0.19
0.20
0.20
0.20
0.20
0.46
0.43
0.50
0.60
0.60
0.62
0.55
0.36
0.21
0.43
0.18
0.17
0.22
0.13
0.16
0.13
0.38
0.45
0.24
0.15
0.24
1.1
1.2
0.99
0.94
0.82
0.74
0.65
0.60
1.0
0.97
1.1
1.3
1.3
1.2
1.2
0.92
0.58
0.94
0.50
0.47
0.43
0.39
0.36
0.38
0.89
1.0
0.58
0.37
0.64
0.71
0.72
0.72
0.80
0.80
0.97
1.10
0.90
0.74
0.87
0.90
0.80
0.80
0.68
0.85
0.84
0.89
0.87
0.92
0.93
0.88
1.67
0.94
0.85
0.82
0.75
0.96
1.05
0.96
-------
Table 6. Sediment pesticides (ug/kg, dry wt.), Bayou Aux Carpes. January 1985.
Compound
Sta. 2
Sta. 3
Sta. 4
Sta. 7
Sta. 8
Sta. 10a
Sta. 10
Sta. 11
Aldrin
80U
60U
20U
100U
20U
200U
200U
10U
Heptachlor
80U
60U
20U
100U
20U
200U
200U
10U
Heptachlor Epoxide
80U
60U
20U
100U
20U
2Q0U
200U
10U
Alpha-BHC
80U
60U
20U
100U
20U
200U
200U
10U
Beta-BHC
80U
60U
20U
100U
20U
200U
200U
10U
Gamma-BHC (Lindane).
80U
60U
20U
100U
20U
200U .
200U
10U
Delta-BHC
80U
60U
20U
100U
20U
200U
200U
10U
Endosulfan I (Alpha)
200U
70U
30U
200U
40U
40U
30U
20U
Dieldrin
200U
70U
30U
200U
40U
40U
30U
20U
4,4'-DDT (P,P'-DDT)
700U
200U
60U
300U
80U
100U
70U
40U
4,4'-DDE (P,P'-DDE)
700U
200U
60U
300U
80U
100U
70U
4QU
4,4'-DDD (P,P'-DDD)
700U
200U
60U
300U
80U
100U
70U
40U
Endrin
700U
200U
60U
300U
80U
100U
70U
40U
Endosulfan II (Beta)
700U
200U
60U
300U
80U
100U
70U
40U
Endosulfan Sulfate
1000U
400U
100U
500U
100U
100U
100U
60U
Chlordane (Tech, Mixture)
800U
300U
100U
800U
20 Ol)
200U
200U
100U
PCB-1242 (Aroclor 1242)
800U
500U
200U
1000U
300U
1000U
2000U
100U
PCB-1254 (Aroclor 1254)
6000U
2000U
600U
3000U
800U
1000U
700U
500U
PCB-1221 (Aroclor 1221)
800U
600U
200U
1000U
300U
1000U
2000U
100U
PCB-1232 (Aroclor 1232)
800U
600U
200U
1000U
300U
1000U
2000U
100U
PCB-1248 (Aroclor 1248)
800U
600U
200U
1000U
300U
1000U
2000U
100U
PCB-1260 (Aroclor 1016)
6000U
2000U
600U
3000U
800U
1000U
700U
500U
PCB-1016 (Aroclor 1016)
800U
500U
200U
1000U
300U
1000U
2000U
100U
Toxaphene
10000U
4000U
1000U
9000U
2000U
2000U
2000U
900U
Endrin Aldehyde
1000U
400U
100U
500U
100U
100U
100U
60U
Methoxychlor
700U
400U
100U
1000U
200U
100U
200U
80U
Moisutre %
90
90
75
70
88
76
78
67
U - Material was analyzed for but not detected. The reported concentration is the minimum detection limit.
-39-
-------
-40-
Table 7. Benthic Macroinvertebrates, Qualitative Collections,
Bayou aux Carpes, Louisiana, January 1985.
Forested Swamp
Marsh
Marsh
Canal
Organism
Sta. 2
Sta. 7
Sta. 8
Sta. 10
Sta. 4
DIPTERA
Glyptotendipes sp.
X
Ablabesmyia peleensis
X
Polypedilum prob. illinoense
X
Goeldichironomus holoprasinus
X
Chironomus plumosus group
X
Tanypus neopunctipennis
X
EPHEMEROPTERA
Siphlonuridae (damaged)
X
ODONATA
Miathyria marcella
X
Pachydiplax longipennis
X
Coryphaeschna ingens
X
Anomalagrion sp.
X
Nasiaeschna sp.
X
Boyeria vinosa
X
Anax amazili
X
Enallagma sp.
X
X
X
Ischnura sp.
X
X
X
HEMIPTERA
Ranatra sp.
X
CRUSTACEA
Hyalella azteca
X
X
X
X
X
Gaimarus sp.
X
Asellus sp.
X
X
X
X
X
Lirceus sp.
X
X
Astacidae
X
X
Astacidae, prob. Cambarellinae
X
Palaemonetes kadiakensis
X
X
Callinectes saoidus
X
X
Uca sp.
X
BIVALVIA
Musculium sp.
X
X
GASTROPODA
Physella prob. heterostropha pomila
X
X
X
X
X
Stagnicola sp.
X
Menetus sp.
X
Fossaria sp.
X
Laevapex sp.
X
X
X
TOTAL TAXA
9
14
1
9
9
14
-------
-41-
Table 8. Fish Collected, Bayou Aux Carpes, Louisiana, January 1985.
Forested Swamp
Marsh
Canal
Orgamism
Sta. 2
Sta. 7
Sta. 10
Sta. 4
21upeidae
Dorosoma cepedianum
X
Engraulidae
Anchoa mitchilli*
X
Dyprinodontidae
Fundulus cingulatus
X
Poecilidae
Gambusia affinis
X
X
X
Heterandria fonrosa
X
X
X
X
Poecilia latipinna
X
Tentrarchidae
Elasscma zonatum
X
X
X
Lepomis punctatus
L. sp.
X
X
TOTAL TAXA
3
4
5
4
^Estuarine species
-------
FIGURE 1
SITE LOCATION
BAYOU AUX CARPES
JANUARY 1985
-------
-4 3-
FIGTJRE 2
BAYOU AUX CARPES
JEFFERSON PARISH, LOUISIANA
-------
-44-
FIGURE 3
HYDROGRAPHIC MONITORING LOCATIONS
BAYOU AUX CARPES
JANUARY 1985
-------
-4 5-
FIGURE h.
Stations for water quality sampling,
Bayou Aux Carpes"Study
January, 1985
0 - Nutrient sampling
(surface grabs.)
-------
-46-
FIGIIRE 5.
Station for biological sampling,
Bayou Aux Carpes Study
block nets (larv
fish &.invertebra
-------
-4 7-
FIGURE 6
WATER LEVELS
BAYOU AUX CARPES
JANUARY 16-20, 1985
: i ,
i ! i
0 i i
> 2 , ; r -I 1
CJ> ; :
52 I I I I
i 1 !
1 1 , , >
1 I ' I
H ! ! . I
^ ("V
c ! i 1 ! 1 < ' "
< _ , _ . . .
w \ \ i *
K V * \
k 0 "1 ; \
BAYOU
AUX
CARPES
-------
DAILY WATER LEVEL RECORDINGS AT 0800 HOURS.
1984 BAYOU
FIGURE 7
COE AT ALGIERS AND BARATARTIA STAGING STATIONS,
AUX CARPES, LOUISIANA
3-i
£
O
£ ¦
i
2-
1
E-
1 -
C!
~
O
0-
>
a)
W
Water Levels
Source: COE
BARATARLA
Mean 1.24
Range 0.33
S. D. 0.44
-1
ni iill ir-rniiiiiiin III|piiI]IiirpiiIIiiiniiirpii|iiiin
Jan I Feb I Mar I Apr I May I Jun I Jul I Aug I Sep I Oct I Nov f Dec I
Jan 84 Dec 84
3-|
o
t-
c
o
H
4->
aJ
>
CD
I
ALGIERS
Mean 1.28
Range 0.17
S. D. 0.53
; 1 | i i i rprIri iiiiiiiirr-iiirniiiiiiirpiiiiiiiir-iiirnIir~iiir-r
I Jan I Feb I Mar I Apr I May I Jun I Jul I Aug I Sep I Oct I Nov I Dec
Jan 84 Dec 84
-------
FIGURE 8
WIND SPEED AND DIRECTION
MOISANT INTERNATIONAL AIRPORT
NEW ORLEANS, LA
JANUARY 1985
Daf.e-Tine
-I7P
0
q II
6$
IM
11
-49-
-------
-50-
FIGURE 9
RAINFALL
BAYOU AUX CARPES
JANUARY 1985
2 -
1/14/85 1/15/85 1/16/85 1/17/85 1/18/85
DATE - TIME
-------
FIGURE 10
WATER LEVEL
EAST BORROW DITCH
LAF I.TTE/LAROSE IIl^Y.
BAYOU AUX CARPES
JANUARY 1985
~1 1 1 1 1 1 1
] 8 00 06 12 18 00 06
1/18/85 1/19/85
DATE - TIME
-51-
-------
-52-
FIGURE 11
WATER LEVEL COMPARISON ON 1/16/85
BAYOU AUX CARPES
JANUARY, 1985
i.o n
"0.5 -
ICW @
ALGEIRS
LOCK
-0 ¦ 1 1 1 1 1 1 1 1
: 0900 1000 1100 1200 1300 1400 1500 1600
1.0
o
:s
"H
S
O
M
H
<
>
W
iJ
W
Pi
U
H
3
0.5 -
BAYOU AUX
CARPES - WEST
END OF EAST-WEST
DRILL.HOLE CANAL.
0--
__I , , ! 1 1 , ,
0900 1000 1100 1200 1300 1400 1500 1600
.Oi
ICW @
BARATARIA
-0.5-
¦O
i i i i : r n i r 'r
0900 1000 1100 1200 1300 1400 1500 1600
TIME
-------
-53-
FIGURE 12
GROUND SURFACE TRANSECTS
BAYOU AUX CARPES
JANUARY 1985
-------
FIGURE 13
FREQUENCY OF, DAILY WATER LEVELS FOR 1984 AT THE COE ALGIERS AND BARATARIA STAGING STATIONS.
BAYOU AUX CARPES, LOUISIANA
1001
50-
Elevation (FT - NGVD)
100 -|
50-
ti|iiii|ir
0.5 1.0
Elevation (FT - NGVD)
-------
WATER
LEVEL
1.35
1.25
1.15
1.05
0.95
400
CHLORIDE 300
200
100
TRACER 100-
CONCENTRATION £ -
& 50
10
" 5.
-------
FIGURE 15
DYE TRACER STUDY
BAYOU AUX CARPES
JANUARY, 1985
20 -
CO
ei
o
:x:
to ¦LJ
<
w
-J
erf
w
cj
<
as-
h
JCT.
10 -
w
a
M
CO
3
J
fi
Hj
<
J
5 -
LEADING EDGE
2 =21.5 HRS.
f Et =3.25 HRS.
= 2.2 5 HRS.
| Et = A.5 HRS.
PIPELINE
.CANAL
~i 1 1 1 1 1 1 1 r
8 10 12 14 16 18 20 22 24
DISTANCE FROM RELEASE POINT (FEET X 1000)
BARATARIA UATERVJAY
r
26
28
30
32
t t
t
t
t
BAYOU AUX
CARPES 0
WITH SNCPL
SNGPL
0
ICW
CROVJN
POINT
LAFITTE
LAROSE
HUY.
FLEMING CANAL
NEAR BARATARIA
-------
-J I -
FIGURE 16
WATER LEVELS, TOTAL ORGANIC CARBON AND TOTAL ORGANIC NITROGEN
SNGP CANAL AT JCT. WITH ICW
BAYOU AUX CARPUS
WATER
LEVEL
1.35
1.25
u
o
& 1.15
1.05
0.95
\
\
\
^Jv
v/
ORGANIC NITROGEN
CONCENTRATION
1.6
1.4
1.2
.0
0.8
0.6
0.4
0.2
1
A
A
P
f\ I
V
f
JJ
V
\1
TOTAL ORGANIC
CARBON
CONCENTRATION
eo
24
20
16
12
8
4
0
i
A
\
\
A
s/
V
r
1
0 1
3 n
n n
; 1
h 1
b - ri
h n
c, I
1/17/35
1/18/85
DATE - TIME
1/19/3.5
-------
-58-
FIGURE 17
VJATER LEVELS AND JT.TROGEN FORMS
SNGP CANAL AT JCT. WITH ICW
BAYOU AUX CARPES
Water
Level
O)
0)
1.35
1.25
1.15
1.05
0. 95
*\
\
\
vi
1.8
1.6
1.4
Nit rogen
Concentration
1.0
. 0.8
0.6
0.4
0.2
0
KEY
NO2-NO3
Organic N
12 18 00 06 12 13 00 06 12
1/17/85 1/18/85 1/19/85-
Date - Time
-------
z
~
<
QL
LJ
U
Z
~
u
\
o
20
F I GURE 18
N02-N0.3, ORG. N. TOC COMPARISON
BAYOU AUX CARPES
JANUARY. 1985
LEGEND
18 --
IB --
14 --
12 --
10 --
8 --
6 --
4 --
2 --
14.9
17. J
.05
1CW
CANALS
MARSH/SWAMP
A N02-N03
ra
ORG. N
TOC
i
u
I
LOCATION
-------
-60-
FIGURE 19.
SEDIMENT SIZE COMPOSITION, CANALS AND ICW,
BAYOU AUX CARPES.
SEDIMENT SIZE COMPOS ITI ON
STATION 3. CANAL
BAYOU AUX CARPES
- »
.1 f
0 9
- H
1
8
B!
m
¦
ijj-j o. eoM'O. mis «o. oom
PARTICLE SIZE
SEDIMENT SIZE' COMPOSITION
STATION 4. CANAL
BAYOU AUX CARPES
particle size
fnm
SEDIMENT SIZE COMPOSITION
STATION 7. CANAL
BAYOU AUX CARPES
SI
IP
Jjj
11
r
"//¦.¦'A
11
a. in-i
PARTICLE. SIZE
ES3
i x
O L
U D
SEDIMENT SIZE COMPOSITION
STATION 1O. CANAL
BAYOU AUX CARPES
ppS
|
cvrgy<
iH
EES
a. us*)
PaRTIC
SEDIMENT "S I IE' COMPOSITION
S i A j i ON ij.,i CW
BAYOU AUX CARPES
mm
-------
-61-
FIGURE 20.
SEDIMENT SIZE COMPOSITION, FORESTED SWAMP AND MARSH,
BAYOU AUX CARPES.
SEDIMENT SIZE COMPOSITION
STATION 2, FORESTED SWAMP
BAYOU AUX CARPES
2-32 0.125-2 O. OO30-O. 0G25 <0.0030
PARTICLE SIZE
mm
0 ^
-l~ 0)
in u
a i
1
x x
a l
u u
h
2
Lli 0
U 0
a
LlI
Q.
SEDIMENT .SIZE COMPOSITION
STATION lOi, MARSH
BAYOU AUX CARPES
KS ' ' ///,
CEDBTO
D. 0039-0. 0625
LEGEND
s Ss /A INORGANIC
PART I CLE -S I ZE
mm
-------
- 6 2-
FIGURE 21.
SEDIMENT SIZE COMPOSITION, FORESTED SWAMP AND I1ARSH,
BAYOU AUX CARPES.
SEDIMENT SIZE COMPOSITION
STATION 7. FORESTED SWAMP
BAYOU AUX CARPES
LEGEND
ORGANIC
INORGANIC
0. 0039-0. 0025
PARTICLE SIZE
mm
Z
0 +)
« L.
t- 01 30
UI 0
O i
Q_
2 X
O L
U U
I- N
Z
ui a
U 0
o:
ui
a.
SEDIMENT -SIZE COMPOSITION
"STATION 8. MARSH
BAYOU AUX CARPES
ImM
mm
811
WlBBi
s
-¦
p&lll
|gg
-¦
¦
-¦
m
ill
m
LEGEND
ORGANIC
inorganic
O.0030-0. 0625
PARTICLE SIZE
mm
-------
FIGURE 22
SEDIMENT METALS mg/kg [d
BAYOU AUX CARPES
JANUARY. 1985
y
300
SWAMP
MARSH CANAL
LOCATION
ICW
w
t J
LEGEND
A ZINC
COPPER
A LEAD
IRON
IRON IS IN THOUSANDS
-------
-64-
FIGURE 23
SEASONAL DISTRIBUTION
WATER LEVELS AT BARATARIA
J" AN - DEC. 1984
j
ui ~
> >
111 (3
JZ
I
KK
Ui U)
Hill
< II
l.B-
1.6-
1.4-
1.2-
1 +
.a-
.0
.4--
.Z--
.78
1
1
i
3
I
3
I
S>
LEGEND
BARATARIA
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
MONTH
ANNUAL MEAN - 1.24
LEGEND
W2
BARATARIA
-------
-65
Figure 24
SEASONAL DISTRIBUTION
h
tL
*
N
U
Z
H
~
III
u
u
x
u
w
z
~
M
h
<
>
K
HI
Ul
0
a
IL
~
K
ui
0
1
30
WATER LEVELS AT
JAN - DEC,
BARATARI A
1 384
23--
20--
13 ¦¦
10--
3--
26
1
*2-
JAN
7
a
FEB
MAR APR
21
I
I
£
17
MAY
id
JUN
JUL
18
i
19
1
AUG
&
g
Sd
12
£
LEGEND
SARA TARIA
SEP OCT NOV DEC
MONTH
U»
>
<
~
IL
~
K
111
0
1
3
Z
SEASONAL DISTRIBUTION
PREDOMINATE WINDS
JAN - DEC, 1984
LEGEND
SOUTHERLY
VTH NORTVERLY
JAN
FEB
MAR
APR
MAY
JUN
JUL AUG
SEP
OCT NOV DEC
MONTH
-------
-66-
Figure 25
1L
*
N
O
Z
H
~
III
lit
u
X
111
to
z
~
M
h
<
>
a.
iii
u
m
~
(L
o
K
Ui
0
1
SEASONAL DISTRIBUTION
WATER LEVELS AT BARATARIA
-JAN DEC, 1984
SO'
23--
20--
1S--
10--
S--
21
12
a
i
7
£
is
17
55
55
B
55
1
55
55
55
55
55
55
is
JAN FEB MAR APR MAY JUN JUL AUG
MONTH
20
12
1
17
1
SEP OCT NOV DEC
LEGEND
BARATARIA
SEASONAL
RAINFALL 8.
JTAN
DISTRIBUTION
WIND DIRECTION
DEC. 1984
LEGEND
RAINFALL In.
WIND FRM NORTH
VINO FRM SOUTH
JAN FES HAR APR MAY JUN JUL AUG SEP OCT NOV DEC
MONTH
-------
APPENDIX A
-------
APPENDIX A
Harvey Canal-Bayou Barataria Levee Project March 31, 1976
See Below
Mr. John C. White
Regional Administrator
EPA Region VI
SUMMARY
As requested, we have surveyed the subject project and offer the following
conclusions. The 3,700-acre tract of wetlands, as it presently relates to
the subject project, remains a valuable and viable parcel of swamp and marsh
area. In view of the value of this resource, we consider Region VI's deci-
sion to request use of a floodgate instead of a pumping station as reasonable,
appropriate, and justifiable.
ACTION
For your information.
BACKGROUND
At your request, we reviewed the present status of the subject project and
determined if existing alterations have Impaired the functioning of the
3,700-acre wetlands to the extent that environmental Impacts of completing
the project {i.e., pumped drainage of the wetlands) would be trivial. The
review was completed the week of March 22 and consisted of briefings, a
site visit to the project area and surrounding environs, and a review of
available documents. The briefings were by Mr. Peter W. Dunsavage of your
office and by staff members of the New Orleans District Corps of Engineers
office (list of attendees at March 23, 1976, meeting is attached). The
site visit was accomplished with the aid of a helicopter. Pertinent docu-
ments were provided by the COE staff.
To complete our evaluation, it will be necessary to briefly describe the
site and the project as they relate -to the Barataria Bay system.
The Site - The Harvey Canal-Bayou Barataria Levee project is an 11,700-acre
(18.3square-mile) tract located near the headwaters of the Barataria Bay
system. The 3,700 acres (5.8 square miles) of the project with which we
axe concerned is predominantly a freshwater system of mainly swamp and some
marsh. The site is near sea level, has an imperceptible gradient, and is
subject to only a slight tidal, influence (0.25 foot).
The Barataria Bay drainage basin, including the 3,700-acre site, 1s approxi-
mately 1,900 square miles and is characterized by distinct p*rallel tones
of vegetation which are noted below.
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APPENDIX A (con't.)
2
Freshwater swamps - Headvaters of the basin featuring swamp forests
(cypress, gum, etc.) with salinity leas than 1 ppt.
Freshwater marshes - Inmediately seaward of swamps and comprised
mainly of herbaceous vegetation with salinity less than 1 ppt;
extensive in upper-central portion of basin.
Intermediate and brackish marshes - Transition zone from fresh to
salt marsh with salinity 5 to 10 ppt.
Salt marsh - Most seaward extension of vegetation (except for scat-
tered mangrove stands near some of the isles) with average salinity
near 17 ppt.
From the above It can be seen that these vegetational zones are highly cor-
related with a specific salinity regime, thus showing that spatial and
temporal variation in the salinity gradient is controlled by freshwater
runoff from the drainage basin where the annual rainfall averages 60 inches.
Reversals of gradient occasionally occur during periods of high runoff from
the Mississippi River.
According to the reports reviewed, Louisiana leads all states in the volume
of commercial fi3h and shellfish harvested. Ninety percent of the harvest
is of estuarlne-dependent species. Barataria Bay, in turn, is described as
the singly most productive estuarine area along the Louisiana coast. Reports
of the LSO Center for Wetland Resources clearly indicate that Louisiana
estuaries owe their high productivity largely to the extensive systems of
marshes and swamps at the land-water interface and to the broad, brackish
zones where salinity fluctuations are tempered by continuous freshwater
inputs from interior storage areas (i.e., the freshwater 9wamps and marshes).
The Project - The Harvey Canal-Bayou Barataria project involves two dis-
tinct subareas:
An 8,000-acre tract whose levees and pumping stations are installed
and operated by local interests.
- A 3,700-acre tract immediately seaward of the 8,000-acre tract which
was unleveed and undrained at the beginning of the federal project.
For purposes of thi3 discussion, reference to the "federal project"
will allude" specifically to the 3,700-acre tract.
Construction of initial levees for the "federal project" were" completed by
the Corps of Engineers in November 1973. Gaps in the levee were loft at
Bayou Aux Carpes, the Southern Natural <3aa pipeline, and a partial opening
at Bayou Dea Families. Subsequent to completion of the levee, -local inter-
ests have completed closure of the Bayou Aux Carpes opening using clam-shell
fill. Plans call for reclamation of the 3,700-acre tract by pump drainage
via a pumping station to be installed at the Bayou Aux Carpes closure. At
present, circulation of water between the 3,700-acre tract and the Intracoaatal
Waterway is via the Southern Natural Gas pipeline canal.
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APPENDIX A (fon't)
Importance of Site - Freshwater swamps and marshes in coastal areas perform
several critical functions including:
Efficient producers of organic natter which support an indigenous
fauna, and surpluses are exported to fuel downstream systems.
Serve as freshwater storage and recharge areas which control the
rate and timing of freshwater inputs to downstream estuaries, thus
maintain a broad zone of salinity gradient throughout the year.
Support an indigenous flora and fauna which is of direct value to
man for recreation, esthetics, sport fishing, and timber production.
Based on observations made during our visit, the 3,700-acre tract is still
performing all of the above functions. The Cypresa-Tupelo Swamp and the
fresh marshes will remain viable as long as they are not/drained. It is
reasonable to expect that they will continue to produce significant quanti-
ties of organic matter to fuel the system. Closure of Bayou Aux Carpes and
the reduction of sheet flow from the system has undoubtedly lessened the
esport of organic matter to downstream systems; however, the Southern
Natural Gas pipeline canal still serves as a major export route of organic
material produced in the swamps and marshes. Installation of a floodgate
at Bayou Aux Carpes, as recommended by EPA Region VI would provide an
additional avenue for export of detritus to downstream systems.
Perhaps the most important function of the freshwater swamps and marshes
in the Barataria Bay system is the amelioration of fluctuations in fresh-
water inputs to the estuary during periodic wet and dry periods. Since
the swamp and marsh Tire intact and connected to the rest of the system via
the pipeline canal, this important function is still taking place.
According to reports of the LSU Center for Wetland Resources, the salinity
of Barataria Bay is determined by basin runoff and inputs from the Mississippi
River. The basin runoff, however, is the major determinant of the salinity
gradient and also serves in a Buffering capacity to maintain uniform salinity
throughout the water year. According to these same reports, the 3,700-acre
tract is part of the zone of major freshwater storage for the Barataria Bay
system. Loss of such storage areas via drainage increases the amplitude
of salinity variations in the brackish zona.
A brief example illustrates the change in freshwater runoff characteristics
brought about by pump drainage:
Eydrologic data:
1. Annual rainfall ~ 60 inches
2. Annual runoff 20 inches (AO inches consumed by evapotranspiration)
3. Rate of discharge following rainfall - 0.20 inch per day.
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APPENDIX A Ccon't)
4
Thua:
1. From 2 above, the mean annual runoff rate from 3,700 acres ¦ 8.5 cfs
2. From 3 above, the runoff rate following rainfall ¦ 31.1 cfs
Based on this analysis, it is apparent that the Initial 150-cfs punp to be
installed will move riinfall at a rate five times greater than the natural
system. As pointed out by the Corps, the initial 150-cfs installation will
only drain a portion of the area. Larger-capacity jumps will ultimately
be installed, thua further increasing the rate of de-watering as compared
with Che natural system.
Finally, we have no doubt that the existing 3,700 acres of wetlands con-
tinues to support an indigenous biota of direct value to man. The present
diking of the 3,700 acres of wetlands nay have reduced public access to
the area; but it fails to eliminate any of the recreational, esthetical,
or sport-fishing features of the tract. In addition, the potential timber
value of the cypress trees remains.as a renewable resource if the area is
not drained.
Writers: L:.B. Tebo, Jr., S&A, Region IV
Delbert B. Hides, SSA, P-egion IV
Thomas R. Cavinder, S&A, Region IV
Victor W. Lambou, EI1&S Lab., Las Vegas
Attachment
LBTebo:pc:2294:3/31/76
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