EPA-600/3-77-090
August 1977
Ecological Research Series
SURVEY OP CROSS-BASIN BOAT TRAFFIC
ATCHAFALAYA BASIN, LOUISANA
Environmental Monitoring and Support Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Las Vegas. Nevada 89114
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S.
Environmental Protection Agency, have been grouped into five series. These
five broad categories were established to facilitate further development and
application of environmental technology. Elimination of traditional grouping
was consciously planned to foster technology transfer and a maximum
interface in related fields. The five series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
This report has been assigned to the ECOLOGICAL RESEARCH series. This
series describes research on the effects of pollution on humans, plant and
animal species, and materials. Problems are assessed for their long- and
short-term influences. Investigations include formation, transport, and
pathway studies to determine the fate of pollutants and their effects. This work
provides the technical basis for setting standards to minimize undesirable
changes in living organisms in the aquatic, terrestrial, and atmospheric environments.
This document is available to the public through the National Technical
Information Service, Springfield. Virginia 22161.
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EPA-600/3-77-090
August 1977
SURVEY OF CROSS-BASIN BOAT TRAFFIC
ATCHAFALAYA BASIN, LOUISIANA
by
Johannes L. van Beek
Benjamin Small
Coastal Environments, Inc.
1260 Main Street
Baton Rouge, Louisiana 70802
Contract No. 68-01-2299
Project Officers
Harold V. Kibby
(Project Officer through August 1975)
Corvallis Environmental Research Laboratory
Corvallis, Oregon 97330
Victor W. Lambou
(Project Officer from September 1975 to Present)
Environmental Monitoring and Support Laboratory
Las Vegas, Nevada 89114
U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
ENVIRONMENTAL MONITORING AND SUPPORT LABORATORY
LAS VEGAS, NEVADA 89114
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DISCLAIMER
This report has been reviewed by the Environmental Monitoring and
Support Laboratory, U.S. Environmental Protection Agency, and approved
for publication. Approval does not signify that the contents necessarily
reflect the views and policies of the U.S. Environmental Protection
Agency, nor does mention of trade names or commercial products constitute
endorsement or recommendation for use.
ii
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FOREWORD
Protection of the environment requires effective regulatory actions
vhich are based on sound technical and scientific information. This in-
formation must include the quantitative description and linking of pollutant
sources, transport mechanisms, interactions, and resulting effects on man
and his environment. Because of the complexities involved, assessment of
specific pollutants in the environment requires a total systems approach
which transcends the media of air, vater, and land. The Environmental
Monitoring and Support Laboratory-Las Vegas contributes to the formation
and enhancement of a sound integrated monitoring data base through multidis-
ciplinary, multimedia programs designed to:
• develop and optimize systems and strategies for moni-
toring pollutants and their impact on the environment
demonstrate new monitoring systems and technologies by
applying them to fulfill special monitoring needs of
the Agency's operating programs
This report addresses one facet in a complex system for assessing
environmental quality mangement associated with flood control in the
Atchafalaya Basin, Louisiana. It describes a boat-traffic survey conducted
to evaluate the need for control structures in light of navigation and
sedimentation in the major cross-basin channels. The U.S. Environmental
Protection Agency, the U.S. Army Corps of Engineers, the U.S. Department
of the Interior, the State of Louisiana, special interest groups, and
other interested individuals will use this information to assess the
potential environmental impact of the massive channelization project
proposed by the Corps. The information will also be useful to those
who develop alternative land and water-quality management plans which
will accommodate flood flows and maintain an acceptable level of
environmental quality. Further information on this survey may be obtained
from the Water and Land Quality Branch, Monitoring Operations Division.
Georgje B( Morgan
Director
Environmental Monitoring and Support Laboratory
Las Vegas
iii
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ABSTRACT
For flood control and for the preservation and enhancement of environmen-
tal quality of overflow swamp habitats, introduction of sediment from the At-
chafalaya Basin Main Channel into backwater areas of the Atchafalaya Basin
Floodway should be minimized. This introduction occurs mainly through di-
version of Main Channel discharge into the old Atchafalaya River Channel and
the four dredged and maintained cross-basin channels that function as distri-
butaries. Therefore, reduction of sedimentation requires structural control
over the volume of flow diverted. A boat-traffic survey was conducted over
the period of August 1975 to May 1976 to evaluate the feasibility of control
structures with regard to navigational use of the West and East Freshwater
Distribution Channels and the West and East Access Channels.
The survey shows that the highest number of traffic occurrences relates
to recreation and involves only small boats (< 6m). This recreation traffic
is mainly sport fishing. The second most frequent usage is for commercial
fishing with this traffic heaviest in the East Access Channel. Usage by the
oil and gas extraction industry ranks third. Oil- and gas-related activities
involve a small number of boats. These include a limited number of tug and
barge combinations, but small crew-boats (< 9 m) dominate. Survey data sug-
gest that only oil- and gas-related traffic requires, at low river stage, the
channel dimensions presently maintained.
In order of importance to navigation, the East and West Access Channels
rank highest. The East Freshwater Distribution Channel has by far the least
number of traffic occurrences.
In addition to the four cross-basin channels, boat traffic on the old
Atchafalaya River channel was also surveyed. Here, traffic occurrences ex-
ceed in number those of the four cross-basin channels combined. In this case,
oil- and gas-related traffic dominates, while sport fishing ranks second.
The traffic data in this report can predict some of the effects on the
various types of boat traffic should the upstream channel entrances be closed
to navigation. The building of navigation provisions as a part of structural
control measures is only one alternative to providing access to the backwater
areas by boats. In this report, the need for building navigation provisions
is discussed in relation to other feasible measures for linking the Main
Channel and the backwater areas for boat traffic.
iv
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CONTENTS
Foreword iii
Abstract iv
Contents v
Figures vi
Tables vii
Acknowledgments viii
1. Introduction 1
2. Conclusions 4
3. Data Acquisition and Analysis 5
4. Results 9
5. Discussion 25
References 29
v
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FIGURES
Number Page
1-1 Location of East and West Access and Freshwater Distribution
Channels and their relative importance in diversion of
Atchafalaya Basin Main Channel discharge 2
3-1 Distribution of traffic surveys as related to river stage 6
4-1 Actual count distribution of traffic in the four channels
surveyed during summer and fall, by type of activity ... 11
4-2 Actual count distribution of boat type, of traffic in all
four channels surveyed, during summer and fall 14
4-3 Actual count distribution of activity-related use by season
for the West Freshwater Distribution Channel 17
4-4 Actual count distribution of boat types by season for the
West Freshwater Distribution Channel 19
4-5 Actual count distribution by activity and season for the
Atchafalaya River Main Channel 23
4-6 Actual count distribution by boat type and season for the
Atchafalaya River Main Channel 24
5-1 Remaining routes for large boats if cross-basin channels
are closed to navigation 27
vi
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TABLES
Number Page
3-1 Number of traffic surveys by season, date and day of week . . 5
3-2 Parameters used for identification of traffic 7
4-1 Actual count (No.) and percentage (%) distribution of traffic
by activity type during summer and fall in the four
channels surveyed 10
4-2 General classification and characteristics of boat traffic
in cross-basin channels 12
4-3 Actual count (No.) and percentage (%) distribution of traffic
by activity type during summer and fall in the four
channels surveyed 13
4-4 Actual count (No.) and percentage (%) distribution of traffic
by activity and season in the West Freshwater
Distribution Channel 16
4-5 Actual count (No.) and percentage (%) distribution of traffic
by boat type and season for the West Freshwater
Distribution Channel 18
4-6 Estimate of number of actual boats involved in traffic on
the four cross-basin channels 20
4-7 Traffic distribution by activity, season, and boat type for
the Atchafalaya River Main Channel 22
vii
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SECTION 1
INTRODUCTION
As part of a land and water resources study of the Atchafalaya Basin,
Louisiana, undertaken jointly by the U.S. Army Corps of Engineers (USCE), U.S.
Fish and Wildlife Service (FWS), and the U.S. Environmental Protection Agency
(EPA), a water management study was initiated by the EPA in 1973. The main
objective of that study was development of a multi-purpose surface water man-
agement plan that would recognize and retain the primary use of the Atchafa-
laya Basin as a floodway, but would sustain or enhance the environmental qua-
lity of the aquatic and swamp forest ecosystems that represent the second
major value of the area. Furthermore, consideration needed to be given to
navigation and oil and gas extraction needs and to other present and projected
uses.
The initial EPA study defined process-form-environment relationships cor-
responding to both natural processes and man's activities within the basin
(Gagliano and van Beek, 1975). Major conflicts between various uses of the
area and requirements for protection and enhancement of the overflow swamps
were determined with respect to the surface water regime. Most salient among
these conflicts are the present incompatibility between uses of the Atchafa-
laya Basin Floodway for flood control and navigation and the hydrologic re-
quirements of its overflow swamps.
Through a second study (van Beek ^ al., 1977), surface water needs for
man's uses and the natural environment were detailed further, and a multi-
use management plan was developed. The single most important aspect of the
plan concerns the need for increased confinement of Atchafalaya Basin flow to
the Main Channel in order to reduce sedimentation in backwater areas. Cur-
rent usage of the basin is not maintaining the area's environmental integrity.
Accelerated sedimentation through both natural and man-induced processes has
greatly altered the former backswamp environments and initiated succession
toward more terrestrial conditions, with an associated deterioration of en-
vironmental quality. These processes, while altering environmental condi-
tions, also reduce the effectiveness of the basin as a floodway.
Presently, four major distributary channels divert both water and sedi-
ment from the main channel into backwater environments. These are the East
and West Freshwater Distribution Channels and the East and West Access Chan-
nels, as shown in Figure 1-1. The map also shows their relative importance
with respect to discharge on the basis of 1975-1976 surveys by the USCE, New
Orleans District. Approximately 15 percent of the Atchafalaya River dis-
charge, measured at Simmesport,is diverted through the cross-basin channels,
and preliminary investigations by the USCE indicate that the associated per-
centage of diverted sediments is even greater.
1
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Henderson 3
B
6.50%
Bayou Sorrel
Lock
Atchafalaya Basin
% PERCENT OF MAIN CHANNEL DISCHARGE
DIVERTED
Morgan
City
* TRAFFIC SURVEY SITES
Figure 1-1.
Location of East and West Access and Freshwater Distribution
Channels and their relative importance in diversion of
Atchafalaya Basin Main Channel discharge.
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There are two reasons why diversions of water into the four distribu-
taries should be limited to only those volumes required for maintaining en-
vironmental quality of the backwater areas. First, it is necessary for en-
vironmental quality and flood control purposes to minimize sedimentation in
backwater areas. Second, limiting diversion will confine channel flow and
aid in Main Channel development through river energy rather than dredging.
However, implementation of structural measures to control diversion, as pro-
posed (Gagliano and van Beek, 1975; van Beek et^ al_., 1977), requires consid-
eration of the navigational use that is made of these channels for various
purposes.
This report presents the results of a study to delineate the use of the
Access and Freshwater Distribution Channels by waterborne traffic. It was
undertaken to evaluate the requirements for diversion control structures.
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SECTION 2
CONCLUSIONS
Access to the Main Channel through the four cross-basin channels is util-
ized primarily for recreational purposes, mainly sport fishing, and involves
only small boats (length < 6 m, draft < 0.6 m).
Commercial fishing traffic, limited to small boats, ranks second and most-
ly uses the East Access Channel.
Traffic related to the oil and gas industry represents the third largest
category and is composed mainly of small crew-boats (length < 9 m, draft
< 1.2 m).
Only a very limited number of large boats, all related to the oil and gas
industry, appear to require dimensions to which channels are presently main-
tained.
Traffic on the Atchafalaya River Main Channel is twice as heavy as the
four cross-basin channels combined.
Atchafalaya River Main Channel traffic relates mostly to oil and gas ex-
traction activities.
Of the four cross-basin channels, the East and West Access Channels are
the most used routes, connecting the Main Channel and backwater areas.
Navigation between the Main Channel and backwater areas would be affected
least by closure of the East Freshwater Distribution Channel.
Maintenance dredging is expensive and also damages the environment.
These costs may outweigh the inconvenience to boat traffic that would result
from a diversion control program that does not include the building of nav-
igation structures.
Besides the cross-basin channels, there are routes presently available
that link the Main Channel and backwater areas. These routes should be eval-
uated as an alternative to building navigation structures associated with
diversion control.
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SECTION 3
DATA ACQUISITION AND ANALYSIS
To determine the present use of the Access and Freshwater Distribution
Channels by waterborne traffic and the needs associated with possible control
structures, traffic surveys were undertaken during the 1975-1976 water year.
Boat traffic counts were made at each of the junctions of the East and West
Access Channels and the East Freshwater Distribution Channel with the Atcha-
falaya Basin Main Channel and at the junction of the West Freshwater Distri-
bution Channel with the Atchafalaya River. Traffic utilizing the channels
relates to several different types of activity. These are commercial fishing,
sport fishing, oil and gas industry exploration and extraction, hunting, and
pleasure boating. Since activities were expected to be influenced on an an-
nual basis by season and river stage, surveys were conducted as shown in TABLE
3-1 and Figure 3-1. The table further shows that in each case, counts were
made over seven consecutive 24-hour periods to incorporate possible variations
associated with weather and working days.
TABLE 3-1. NUMBER OF TRAFFIC SURVEYS BY SEASON, MONTH, AND DAY OF WEEK
NO, SEASON
MONTH
FRI. SAT. SUN. MON. TUB. WED. THU. FRI. SAT.
4
4
1*
1*
Summer
Fall
Winter
Spring
August I9
November
Jan/Feb 30 9
May
2
I9
31
I8
3
2
1
2
4
3
2
3
5
4
3
4
6
5
4
5
7
6
5
6
89
7
69
7
89
89
* East Freshwater Distribution Channel only
Half-day only
The traffic count had two specific goals. One was to determine to what
type of activity traffic in each of the channels related. The other was to
obtain information concerning type, size, and draft of vessels and direction,
time, and day of traffic occurrences in order to evaluate navigation needs to
be incorporated in diversion control. The data at each of the four locations
were obtained by counting and identifying all traffic occurrences over the
seven consecutive 24-hour periods. Parameters used in identification are
listed in TABLE 3-2. Observations were recorded in code form in the field.
Survey personnel were stationed at each location for the entire seven-day
period.
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TABLE 3-2. PARAMETERS USED FOR IDENTIFICATION OF TRAFFIC
1. Survey station
2. Date
3. Time
4. Day of week
5. Direction in distributary
channel (in, out)
6. Direction in main channel
(up, down)
7. Boat type
a) Bateau
b) Bass boat
c) Small crew-boat (< 10 m)
d) Large crew-boat (> 10 m)
e) Tug
f) Tug and barge
g) Pleasure craft
h) Other
8. Size
a) < 6 m
b) 6-10 m
c) > 10 m
9. Draft
a) < 0.6 m
b) 0.6-1.2 m
c) > 1.2 m
10. Number of persons
11. Activity
a) Commercial fishing
b) Sport fishing
c) Oil and gas production
d) Pleasure boating
e) Surveying
f) Dredging
g) Hunting
h) Other
(MOV I TlfK I -IAN T^ ff». I liAR I APR I I1AV 1
FES ' MAM ' APR ' MAY ' JUM
Figure 3-1. Distribution of traffic surveys as related to river stage.
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Traffic data for the summer and fall periods were collected at each of
the four channel junctions. Following the first two counts and examination
of resulting data, it was deemed sufficient to retain only the site at the
West Freshwater Distribution Channel and Atchafalaya River. This site was
selected because information could be obtained simultaneously for the two
channels and because it showed slightly more variation. Thus, winter and
spring surveys were limited to one site.
Computer analysis of the raw field data was performed by the Statistical
Analysis System (SAS). The data were sorted by the SAS program into fre-
quency distributions by year, month, day and station; within these major
subdivisions, the data were tabulated to show frequency of boat type, activ-
ity, direction of traffic, size, draft of vessel, and number of persons per
boat. Additionally, traffic occurrence was tabulated to indicate peak
periods of channel usage. Based on displays derived from this analysis,
intensity and type of traffic were determined.
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SECTION 4
RESULTS
Cross-basin navigational traffic utilizing 1) the West Freshwater Dis-
tribution Channel (WFDC), 2) the East Freshwater Distribution Channel (EFDC),
3) the West Access Channel (WAC), and 4) the East Access Channel (EAC) is en-
gaged in four major types of activities. These are recreation (sport fishing,
hunting, pleasure boating), commercial fishing, oil- and gas-related activi-
ties, and survey and dredging. TABLE 4-1 and Figure 4-1 compare activity-
related use in all four channels, using summer and fall data; winter and
spring data were omitted since they apply only to the EFDC. These data have
been further broken down for each channel to show the traffic at each station
and its composition in regard to activity.
Analysis of TABLE 4-1 and Figure 4-1 indicates that the dominant use of
all cross-basin channels is recreation-oriented, constituting 33.26% of all
traffic in the four channels. Nearly all recreational usage falls into the
sport fishing category. On an individual channel basis, the same conclusion
is reached for the WFDC, EFDC, and WAC, but does not apply to the EAC, use of
which is dominated by commercial fishing. (The East Access Channel links the
settlement of Bayou Sorrel at the Floodway Protection Levee with the Atcha-
falaya River Main Channel, which is fished especially for catfish.) The WFDC,
EFDC, and WAC are used by commercial fisherman to a much lesser extent; how-
ever, commercial fishing still ranks second in channel usage.
Traffic related to oil and gas production ranks third in the total sam-
ples. However, individual channels present a different picture. Oil- and
gas-related usage equals sport fishing, the largest single recreational use
at that location, at the WFDC, and is dominant over commercial fishing use at
the WAC. Usage is entirely related to maintenance and inspection of produc-
tive oil and gas fields in the vicinity of the channels. Most oil- and gas-
related traffic occurrences involve personnel transport.
While remaining usage categories are minor in terms of number of occur-
rences, dredging and surveying activity deserves further comment. At present,
the depth of the Access Channels is authorized to be maintained at 2.7 m be-
low MSL. Effective water depths thus range from about 3 m to 7.5 m, depending
on river stage. Of all the types of boat activity observed in this survey,
only tugboats, barges, and crew boats require such depths. Therefore, sur-
veying and dredging activities primarily support the work of oil and gas
companies. Dredging and survey related traffic at the EAC and WAC is not
part of the daily traffic picture because it only takes place annually or
bi-annually.
8
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TABLE 4-1. ACTUAL COUNT (NQ) AND PERCENTAGE (%) DISTRIBUTION OF TRAFFIC BY ACTIVITY TYPE DURING
SUMMER AND FALL IN THE FOUR CHANNELS SURVEYED
^^ ^ ^ COMUIAIIVE
ACTIVITY TYPE No. % No. % No. % No. % No. %
Commercial Fishing 55 22.45 30 25.00 71 17,02 256 46.55 412 30.93
Sport Fishing 77 31.43 59 49.17 138 33.09 94 17.09 368 27.63
Oil and Gas Industry 77 31.43 0 0.00 127 30.46 82 14.91 286 21.47
Pleasure Boating 3 1.22 0 0.00 2 0.48 1 0.18 6 0.45
Surveying 0 0.00 4 3.33 6 1.44 22 4.00 32 2.40
Hunting 28 11.43 11 9.17 6 1.44 24 4.36 69 5.18
Dredge 0 0.00 0 0.00 43 10.31 56 10.18 99 7.43
Other 5 2.04 16 13.33 24 5.76 15 2.73 60 4.51
TOTAL ACTIVITY 245 100.00 120 100.00 417 100.00 550 100.00 1332 100.00
*West Freshwater Distribution Channel
<*East Freshwater Distribution Channel
"t"West Access Channel
§East Access Channel
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100 -j
80-
60-
40-
20-
0
WFDC
LEGENDJTYPE OF ACTIVITY
1 COMMERCIAL FISH
SPORT FISH
OIL * GAS
DREDGE * SURVEY
HUNTING
PLEASURE BOAT
100-
80-
o
o
1 I 2 I 3 I 4 15 I 6 I 7 I
TYPE OF ACTIVITY
OTHER
20-|
0
EFDC
14151
2 I 3 I 4 I 5 I 6 171
TYPE OF ACTIVITY
EAC
5 I 6 I 7 I
TYPE OF ACTIVITY
3 I 4 I 5Te I 7 I
TYPE OF ACTIVITY
3 I 4 I 5 I 6 I 7 I
TYPE OF ACTIVITY
Figure 4-1. Actual count distribution of traffic in the four channels surveyed
during summer and fall, by type of activity.
10
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The above-described usage of the four cross-basin channels by various
interests indicates the potential impact of channel closure or modification
on traffic activities. One possible modification is control with provision
for navigation. Therefore, it is important to know the draft, size, and types
of craft used for activities involving the channels. Boats are classified
according to their size and draft combination. TABLE 4-2 gives the size and
draft limits used for each of the defined boat types.
The results of the inventory of various boat types occurring on the four
channels are presented in TABLE 4-3, and graph comparisons are presented in
TABLE 4-2. GENERAL CLASSIFICATION AND CHARACTERISTICS OF BOAT TRAFFIC IN
CROSS-BASIN CHANNELS
BOAT TYPE
Small Boats
Small Crew Boats
Large Crew Boats
Tug Boats
Tugs and Barges
Pleasure Boats
SIZE
3 - 6 m
< 9m
> 9 m
> 9m
> 9m
3 - 6 m
DRAFT
0 - 0.6 m
0 - 0.6 m
0.6 - 1.2 m
0.6 - 1.2 m
> 1.2 m
> 1.2 m
> 1.2 m
Variable
Figure 4-2. Examination of these data shows that the predominant type of
boat used in the basin is the small boat. This type is less than 20 feet
long, has a draft requirement of less than 2 feet, and is usually flat-
bottomed and blunt-nosed. It is used for all activities within the basin,
but is primarily used for commercial fishing and recreational pursuits. The
small crew-boat, the second most common type using the channels, is generally
less than 30 feet long and has a draft of less than 4 feet. It is used in
oil- and gas-related activities and for dredging and survey activities.
While the frequency of this type of craft is considerably less than the small
boat type, the small crew-boat represents an important portion of the traffic
utilizing these four channels.
Large crew-boats, tug boats, and tug and barge combinations in the
WAC and EAC are primarily engaged in maintenance dredging of both of these
channels. The majority of tug and barge occurrences is used to transport
equipment necessary for dredging operations, while the remainder is related
to oil and gas activities. In the WFDC, all large boat categories are re-
lated to the oil and gas industry; no such occurrences were observed at the
11
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TABLE 4-3. ACTUAL COUNT (NO.) AND PERCENTAGE (%) DISTRIBUTION OF TRAFFIC BY BOAT TYPE DURING
SUMMER AND FALL IN THE FOUR CHANNELS SURVEYED
WFDC EFDC3 WACf EAC§ COMBINED TOTAL
BOAT TYPES
Small Boats
Small Crew Boats
Large Crew Boats
Tug Boats
Tugs and Barges
Pleasure Boats
Other
No. % No. % No. % No. % No. %
168 68.57 114 95.00 270 64.75 429 78.00 981 73.65
63 25.72 6 5.00 102 24.46 65 11.82 236 17.72
4 1.63 0 0.00 4 0.96 2 0.36 10 0.75
6 2.45 0 0.00 13 3.11 13 2.36 32 2.40
4 1.63 0 0.00 26 6.24 31 5.64 61 4.58
0 0.00 0 0.00 1 0.24 5 0.91 6 0.45
0 0.00 0 0.00 1 0.24 5 0.91 6 0.45
* West Freshwater Distribution Channel
3 East Freshwater Distribution Channel
t West Access Channel
§ East Access Channel
-------
o
0
200-
180-
160-
140-
100-
80-
60-
40-
20-
0
300-
280-
260-
240-
220-
200-
180-
^1
§ 140-
120-
100-
80-
60-
40-
20-
0
WFDC
WMIIIUM mm///?,,!,,,,,,
2 I 3 I 4 I 5 I 6 I 7 I
BOAT TYPE
WAC
f>/l/JM////tfJ//tt.
_ 3Ti I 5 I 6 I 7 I
BOAT TYPE
LEGEND:BOAT TYPE
1 SMALL BOATS
2 SMALL CREW BOATS
3 LAROE CREW BOATS
4 TOG
5 TUG »BARGE
6 PLEASURE CRAFT
7 OTHER
3 I 4 I 5 I 6 I 7
BOAT TYPE
Figure 4-2. Actual count distribution by boat type, of traffic in all four
channels surveyed, during summer and fall.
13
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EFDC. Summertime tug and barge traffic in the EAC is largely related to a
single boat stationed at Bayou Sorrel, but applies in the western part of
the floodway.
Data from the WFDC provide a picture of seasonal variations, presented
in TABLE 4-4 and in Figure 4-3. These show the distribution of the various
activities throughout the year as based on the four one-week counts within
each season.
Examination of TABLE 4-4 and Figure 4-3 shows that all of the activities
occurring at the WFDC are influenced by season. Both the recreational activ-
ities of sport fishing and hunting as well as commercial fishing are limited
by environmental conditions which affect fish and wildlife. Peak commercial
fishing and sport fishing activities are concentrated in the spring during
peak periods of biological activity; hunting activities are limited to state
and federally regulated fall and winter hunting seasons. Seasonal variation
is also associated with traffic related to oil and gas extraction activities,
which show highest occurrence during the winter and fall periods and somewhat
reduced levels during spring and summer. Although the observed distribution
of oil- and gas-related traffic appears to be seasonal, variations could re-
late to new exploration in the area and may not represent a seasonal traffic
picture in regard to maintenance of existing fields and production facilities.
Since small boats are related mainly to commercial fishing and recreation
and large boats to oil and gas production and dredging, seasonal variation by
boat types is expected to follow largely that shown by activity. TABLE 4-5
and Figure 4-4 display these data and confirm that expectation. Comparison
of seasonal variation by activity and boat type further shows that oil and
gas activities are to some extent carried out with shallow-draft, small boats.
The use of this type of boat is limited to transportation of one to three
people to and from work.
In addition to the types of activity to which channel use relates and
types of boats that are associated with those activities, frequency of boat
use was examined on an hourly and daily basis. These data do not prove to be
of major importance. Daily traffic is spread fairly evenly over the entire
seven-day period at all sample points. The hourly time breakdown of traffic
frequency shows a slight seasonality in that as the days became longer, traf-
fic begins earlier and ends later. Both of these factors are inconsequential
in the make-up of the boat traffic and activities associated with these chan-
nels.
The data presented so far have dealt with traffic occurrences only. The
actual number of boats involved in this traffic is substantially less, since
the same boat may be counted more than once as a traffic occurrence during
each survey. An estimate of the actual number of boats using the cross-basin
channels for various types of activity was obtained and is shown in TABLE 4-6.
Field observations showed that, on all channels, inbound traffic equaled
outbound traffic and involved the same boats. Therefore, to obtain the num-
ber of boats, all traffic counts should first be halved. The number is fur-
ther reduced because in most instances traffic related to commercial fishing
14
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TABLE 4-4. ACTUAL COUNT (NO.) AND PERCENTAGE (%) DISTRIBUTION OF TRAFFIC BY ACTIVITY AND SEASON
IN THE WEST FRESHWATER DISTRIBUTION CHANNEL
ACTIVITY
WINTER SPRING SUMMER FALL COMBINED TOTAL
No. % No. % No. % No. % No. %
Commercial Fishing
7.61 18 13.95 50 37.59
4.46 80 17.17
Sport Fishing
34 36.95 76 58.92 53 39.85 24 21.43 187 40.13
Oil and Gas Industry 50 54.35 30 23.26 27 20.30 50 44.64 157 33.69
Boating
Surveying
0 0.00
1 1.09
0.77
0 0.00
0.00
0.00
2.68
0 0.00
0.86
0.21
Hunting
Unknown
0.00
0 0.00
0 0.00
3.10
0.00 28 25.00 28 6.01
2.26
1.79
1.93
-------
SUMMER
LEGENDTYPE OF ACTIVITY
1 I2I3I4I5I6I7I
TYPE OF ACTIVITY
100 n
80-
8
20-
0
SPRING
3 I 4 I 5 I 6 I 7
TYPE OF ACTIVITY
FALL
I2I3I4I5I6I7I
TYPE OF ACTIVITY
4 I 5 I 6 I 7
TYPE OF ACTIVITY
1 I 2I3I4I5I6I7I
TYPE OF ACTIVITY
Figure 4-3. Actual count distribution of activity-related use by season for
the West Freshwater Distribution Channel.
16
-------
TABLE 4-5. ACTUAL COUNT (NO.) AND PERCENTAGE (%) DISTRIBUTION OF TRAFFIC BY BOAT TYPE AND
SEASON FOR THE WEST FRESHWATER DISTRIBUTION CHANNEL
BOAT TYPES
WINTER SPRING SUMMER FALL COMBINED TOTAL
No. 7, No. % No. % No. % No. %
Small Boats
Small Crew Boats
Large Crew Boats
Tug Boats
Tugs and Barges
Pleasure Boats
61 66.30 100 72.52 106 79.70 62 55.36 329 70.60
31 33.70 25 19.38 21 15.79 42 37.50 119 25.54
0.00
0 0.00
0.78
0 0.00 0 0.00
2.32
0 0.00 0 0.00
3.01
0 0.00
1.50
0.00
0 0.00
0.00
3.57
3.57
1.07
0.00
1.93
0.86
Other
0 0.00 0 0.00
0 0.00
0 0.00 0 0.00
-------
SUMMER
I 3 I 4 I 5 I 6 I 7 I
BOAT TYPE
SPRING
3 I 4 I 5 I 6 I 7 I
BOAT TYPE
40O-,
380-
360-
340-
320-
3OO-
280-
260-
240-
_220-
§200-
0 180-
16O-
14O-
120-
1OO-
80-
6O-
40-
20-
LEGEND;BOAT TYPE
1 SMALL BOATS
100-
2 SMALL CREW BOATS
80-
3 LARGE CREW BOATS
Z 60-
§ 40-
5 TUG 4 BARGE
20-
6 PLEASURE CRAFT
0 —
7 OTHER
1
•
i
Im
100 -,
80-
^ 60-
§ 4°-
20-
•UIIHIttl V/i/lm,
[3141516^71
FALL
i
1 I2l3l4l5l6l7
BOAT TYPE
WINTER
•
jj
1 I2l3l4l5l6'7l
BOAT TYPE
BOAT TYPE
Figure 4-4. Actual count distribution of boat types by season for the
West Freshwater Distribution Channel.
18
-------
and oil- and gas-related personnel transport is part of a daily work routine,
so that those boats are re-counted during every day of the traffic survey.
Traffic counts related to these two activity types should therefore be di-
vided also by the number of survey days.
To obtain the number of boats on an annual basis, traffic counts for the
East and West Access Channels and the East Freshwater Distribution Channel
must be extrapolated using the seasonal distribution shown by traffic data
from the West Freshwater Distribution Channel where counts were obtained
during each of the four seasons.
For example, the number of traffic counts related to commercial fishing
for the East Access Channel was 256 in 14 days of counting during summer and
fall. Starting with the seasonal distribution of commercial fishing counts
for the West Freshwater Distribution Channel, the total count for 28 days
extending over all four seasons would have been 256 + 25/55 x 256 = 372 (in
the WFDC, 25 counts occurred in spring and winter and 55 counts in summer and
fall). Assuming that boats are counted twice each day during the 28 days of
the survey, the number of boats per day estimated to be involved in commercial
fishing and to be making use of the Fast Access Channel connection with the
Main Channel is therefore 372 T 2 * 28 = 7. The same reasoning is likely to
apply to most instances of oil- and gas-related traffic.
An estimate of the number of recreation-related boats is more difficult
to obtain. While each of those boats was also counted twice, the frequency
with which the same sport fishing or hunting boat uses the same channel is
unknown. The assumption made to obtain the number of recreation-related
boats is that each of those boats uses the same channel once a month. If this
estimate is too frequent, the number of recreation-related boats would be
higher accordingly.
TABLE 4-6. ESTIMATE OF NUMBER OF ACTUAL BOATS INVOLVED IN TRAFFIC ON THE
FOUR CROSS-BASIN CHANNELS
ACTIVITY
Commercial
Fishing
Recreation
Oil and Gas
WEST
FRESHWATER
DISTRIBUTION
CHANNEL
2
117
3
EAST
FRESHWATER
DISTRIBUTION
CHANNEL
1
85
-
WEST
ACCESS
CHANNEL
2
184
5
EAST
ACCESS
CHANNEL
7
137
3
TOTAL
12
523
11
Total
122
86
191
147
546
The survey of the four cross-basin channels also presented an oppor-
tunity to assess traffic at the junction of the Atchafalaya River with the
West Freshwater Distribution Channel. The Atchafalaya River, which parallels
19
-------
the Main Channel (Figure 1-1), diverts approximately 30 percent of the Main
Channel flow. Only about half of this flow is returned when the Atchafalaya
River joins the Main Channel again; the other half feeds the West Freshwater
Distribution Channel and other lesser channels, while some water may be lost
through overbank flows. The Atchafalaya River is the main source of water
for annual freshwater flooding of the Henderson sub-basin located west of
Butte La Rose. Proposed control over diversion of water through the Atchafa-
laya River as part of a water management plan was discussed in an earlier re-
port (van Beek et al., 1977),
Atchafalaya River traffic counts include only traffic moving up and down
that channel past its junction with the West Freshwater Distribution Channel.
The survey period and frequency were the same as for the West Freshwater Dis-
tribution Channel. The results are shown in TABLE 4-7, Figure 4-5, and Fi-
gure 4-6.
Comparison of the above tables and graphs with those for the cross-basin
channels reveals that there are twice as many traffic occurrences compared to
the other four channels combined. A number of conditions contribute to this
heavy usage. These are a major oil and gas operation along the Atchafalaya
River channel south of its junction with the WFDC, the development of new
well locations between the traffic survey site and Butte La Rose, and a
dredging operation upstream from the survey site. These operations mean a
daily movement of personnel, equipment, and materials from Butte La Rose to
the existing oil' field and movement mainly of heavy earthmoving equipment up-
stream from the Main Channel to new well locations and the dredging operation.
It was not possible to estimate to what extent traffic utilized the connection
between the Atchafalaya River and the Main Channel. The tables and graphs
thus represent only a picture of traffic utilizing the Atchafalaya River
channel.
TABLE 4-7 and Figure 4-5 show that oil- and gas-related activities ac-
count for 60 percent of the traffic occurrences. Comparison of Figures 4-5
and 4-6 reveals also that this activity accounts for most large and small
crew boats, tugs, and tug-barge combinations plus a significant number of
small boats. Dredging operations involve a low number of small crew^-boats
and some barges.
Traffic related to commercial and sport fishing is light when compared to
both oil- and gas-related traffic in the Atchafalaya River and similar traffic
in the four other channels. The same is true for the other recreational
categories. The extent to which commercial fishing and recreational traffic
moves beyond the Atchafalaya River into the Main Channel is unknown. Again,
the number of boats involved is small when taking into account the previously
mentioned consideration regarding multiple counts. Commercial fishing boats
would be in the order of two or three, and recreational boats about 120. As-
suming a daily work routine for all oil- and gas-related traffic gives a to-
tal of ten boats related to that activity,
20
-------
TABLE 4-7. TRAFFIC DISTRIBUTION BY ACTIVITY, SEASON,
RIVER MAIN CHANNEL
AND BOAT TYPE FOR THE ATCHAFALAYA
to
ACTIVITY
Commercial Fishing
Sport Fishing
Oil and Gas
Dredge and Survey
Hunting
Pleasure Boating
Other
BOAT TYPE
Small Boat
Small Crew Boat
Large Crew Boat
Tug
Tug and Barge
Pleasure Boat
Other
TOTAL
No. %
53
210
516
32
17
12
18
No.
362
202
125
8
144
17
0
6
24
60
3
1
1
2
TOTAL
42
23
14
0
16
1
.18
.48
.14
.78
.98
.40
.09
%
.19
.54
.57
.93
.78
.98
0
WINTER
No. %
9 4.
44 20.
136 61.
25 11.
0
5 2.
1 0.
WINTER
No. %
96 43.
84 38.
0
0
40 18.
0
0
09
00
82
36
0
27
46
SPRING
No. %
19
97
81
3
0
5
10
8.84
45.11
37.67
1.40
0
2.33
4.63
SPRING
No. %
64
18
0
0
18
0
0
135
27
21
1
31
0
0
62.79
12.50
9.77
0.46
14.42
0
0
SUMMER
No. I
14 5.
48 17 .
211 75.
0
0
0
6 2.
SUMMER
No. I
82 29.
43 15.
100 35.
3 1.
50 17.
1 0.
0
FALL
; NO. %
02
20
63
0
0
0
15
39
41
00
08
92
36
0
11
21
88
4
17
2
1
FALL
No.
49
48
4
4
23
16
0
7.64
14.38
61.11
2.78
11.81
1.39
0.69
%
34.03
33.33
2.78
2.75
15.97
11.11
0
-------
SUMMER
4 I 5 I 6 I 7
TYPE OF ACTIVITY
SPRING
3 I 4 I 5 I 6 I 7 I
TYPE OF ACTIVITY
LEGEND :TYPE OF ACTIVITY
1 COMMERCIAL FISH
2 SPORT FISH
3 OIL a GAS
4 DREDGE 4 SURVEY
5 HUNTING
6 PLEASURE BOAT
7 OTHER H
FALL
2 I 3 I 4 I 5 I 6 I 7 I
TYPE OF ACTIVITY
WINTER
2l3l4l5l6l7l
TYPE OF ACTIVITY
1 I 2 T 3 I 4 I 5 I 6 I 7 I
TYPE OF ACTIVITY
Figure
4-5. Actual count distribution by activity and season for the
Atchafalaya River Main Channel.
22
-------
SUMMER
it
213141516)71
BOAT TYPE
LEGEND:BOAT TYPE
1 SMALL BOATS
2 SMALL CREW BOATS
3 LARGE CREW BOATS
4 TUG
5 TUG « BARGE
6 PLEASURE CRAFT
7 OTHER
FALL
TOTAL
8
I 2 I 3 I 4 I 5 I 6
BOAT TYPE
7l
100-
80-
60-
20-
0
WINTER
2I3I4I5I 6171
BOAT TYPE
Figure 4-6. Actual count distribution by boat type and season for the
Atchafalaya River Main Channel.
23
-------
SECTION 5
DISCUSSION
The traffic survey shows that In terms of traffic occurrences, number of
actual boats, and number of people, the primary usage of the four cross-basin
channels is for recreational purposes, involving only small boats having a
length of less than 6 m and a draft requirement of less than 1 m.
The second major usage is commercial fishing. This appears to involve a
very small number of boats and people insofar as use of the Main Channel and
access to it by one of the four channels are concerned. Usage is heaviest for
the East Access Channel route, where it relates largely to summer night fishing,
The third major usage of the cross-basin channels relates to the oil and
gas industry, with a limited number of small crewrboats as the main type of
vessel. In addition, an even more limited number of large crewr-boats and tug-
barge combinations is utilized. No use is made of the East Freshwater Diver-
sion Channel for oil- and gas-related activities. Although not observed,
occasional use may be made of the East Access Channel, West Access Channel,
and West Freshwater Distribution Channel for movement of drilling rigs from
the Main Channel to backwater areas. Alternate routes for this action are
available, however.
At this point, it may be asked to what extent cross-basin navigation is
a necessity, considering the observed traffic. What alternatives are avail-
able to make water management possible?
Recreational use of the four channel junctions with the Main Channel may
be called a matter of convenience rather than necessity. Roads, boat ramps,
and backwater channels provide ready access to all areas of the Atchafalaya
Floodway utilized for sport fishing and most hunting. Hunting grounds along
the Main Channel levee complex are somewhat less accessible, but can be
reached from Butte La Rose and Myette Point. Structural control over fresh-
water diversion into the West Access Channel, East Access Channel, West Fresh-
water Distribution Channel, and East Freshwater Distribution Channel, without
navigation provisions, would not affect the recreational resource value of
the area. It would only force an early decision on the part of the sport
fisherman or hunter whether to try his luck in the western or the eastern half
of a 60-square-mile area. The size of the cross-basin channels is clearly
far in excess of recreational needs.
Commercial fishing would be adversely affected by structural controls
without navigation provisions. On the west side, such action would be par-
tially offset by access to the Main Channel from Butte La Rose and Myette
24
-------
Point. This would increase maximum travel distance by about 30 km. No al-
ternative access points are present along the east side. Minimizing impact
on commercial fishing would require provision in the structural controls for
small boat passage. The cost of such a provision should be weighed against
compensatory payments for lost income or other mitigation programs, especially
since there is a small number of persons involved. As with sport fishing,
the size of the channels is clearly in excess of commercial fishing usage and
needs.
Closure of the four channels to cross-basin navigation would clearly have
the greatest impact on oil- and gas-related traffic at the West Freshwater
Distribution Channel. The traffic survey did not, however, show an absolute
need for such cross-basin traffic. It did, on the other hand, suggest that
the frequent and high-cost dredging and maintenance of large channels and the
associated detrimental deposition of spoil are solely, or nearly so, in sup-
port of mineral extraction. This means that costs of alternative provisions
for the oil and gas industry should be weighed not only against the environ-
mental quality benefits derived from structural control of diversion, but
also against those cost benefits derived through reduced dredging and main-
tenance needs.
Provision of navigation locks that allow crew boat and barge passage
would be an extremely costly action, particularly when considering the very
small number of boats involved. Traffic certainly would not warrant four
such structures. In case such structures were decided upon, however, the
obvious choice on the basis of traffic occurrences would be the East and West
Access Channels. Combined with existing backwater routes, these navigation
locks would maintain access to all areas presently served by the four chan-
nels while also providing for cross-basin navigation.
Closure to navigation of all four channels would not necessarily limit
oil- and gas-related activities. Feasible solutions to such a constraint are
available in view of existing navigation routes within the East and West
Floodway segments. Considering the small number and types of boats involved
in the daily work routine, the stationing of a single tug-barge combination
and a number of small crew boats in both the East and West Floodway segments
could well be a more economical solution than provision of navigation locks
and high-cost channel maintenance. Requirements of additional support traf-
fic on an incidental basis could still be met via the Alternate Route of the
Intracoastal Waterway within the eastern half of the floodway and Borrow Pit -
Fausse Point Cut combination in the western half. Both routes connect with
the lower reach of the Main Channel. Navigation routes available for large
boats should the four channel entrances be closed to traffic are shown in
Figure 5-1.
Much more difficult to evaluate are the effects related to closure of the
Main Channel - Atchafalaya River connection to navigation. The difficulty
arises from the fact that only in-channel traffic was surveyed under the
limited scope of this study. Considerations related to sport and commercial
fishing, and to some extent oil and gas operation are, nevertheless, the same
as for the four cross-basin channels. There remains, however, a need for ac-
cess to the Main Channel, especially if access were eliminated through clo-
25
-------
L. _ _U_S_H~»_ 190
__ Henderson \
— x,
Butte La Rose^r
X
PROPOSED MANAGEMENT
CONTROL STRUCTURES
AVAILABLE NAVIGATION
ROUTES
Atchafalaya Basin
Figure 5-1. Remaining routes for large boats if cross-basin channels are
closed to navigation
26
-------
sure of the cross-basin channels. Closure of the Atchafalaya River - Main
Channel junction would eliminate, however, the need for closure of the West
Freshwater Distribution Channel since the latter is a distributary of the
Atchafalaya River. Navigational access to the Main Channel for incidental
activities would be maintained via the existing western route (Figure 5-1).
On the other hand, a new vantage point for regular surveying and maintenance
operations along the Main Channel would have to be established as a substitute
for the present Butte La Rose Landing and to accommodate recreational activ-
ities related to the Main Channel. A logical site for such a new landing
would be the intersection of Interstate Highway 10 and the Main Channel.
27
-------
REFERENCES
Gagliano, Sherwood M., and Johannes L. van Seek. 1975, Environmental Base
and Management Study, Atchafalaya Basin, Louisiana. EPA-600/5-75-
006, U.S. Environmental Protection Agency, Washington, D.C. 226 pp.
van Beek, Johannes L., William G. Smith, James W. Smith, and Phillip Light.
1977, Plan and Concepts for Multi-Use Management for the Atchafalaya
Basin, Louisiana. U.S. Environmental Protection Agency, Environmen-
tal Monitoring and Support Laboratory, Las Vegas, Nevada.
(In Press) 204 pp.
28
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/3-77-090
r
4. TITLE AND SUBTITLE
SURVEY OF CROSS-BASIN BOAT TRAFFIC ATCHAFALAYA BASIN,
LOUISIANA
3. RECIPIENT'S ACCESSION»NO.
5. REPORT DATE
August 1977
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Johannes L. van Beek, Benjamin Small
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Coastal Environments, Inc.
1260 Main Street
Baton Rouge, Louisiana 70802
10. PROGRAM ELEMENT NO.
IAD 606
11. CONTRACT/GRANT NO.
68-01-2299
12. SPONSORING AGENCY NAME AND ADDRESS
U.S. Environmental Protection Agency-Las Vegas, NV
Office of Research and Development
Environmental Monitoring and Support Laboratory
Las Vegas, NV 89114
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
EPA/600/07
15. SUPPLEMENTARY NOTES
16. ABSTRACT
For flood control and for the preservation and enhancement of environmen-
tal quality of overflow swamp habitats, introduction of sediment from the At-
chafalaya Basin Main Channel into backwater areas of the Atchafalaya Basin
Floodway should be minimized. This introduction occurs mainly through di-
version of Main Channel discharge into the old Atchafalaya River Channel and
the four dredged and maintained cross-basin channels that function as distri-
butaries. Therefore, reduction of sedimentation requires structural control
over the volume of flow diverted. A boat-traffic survey was conducted to
evaluate the need for control structures with regard to navigational use
of the West and East Freshwater Distribution Channels and the West and East
Access Channels. The survey shows that the highest number of traffic occur-
rences relates to recreation and involves only small boats. The second most
frequent usage is for commercial fishing with use of the East Access Channel
being heaviest. Usage by the oil and gas extraction industry ranks third.
Survey data suggest that only oil- and gas-related traffic requires, at low
river stage, the channel dimensions presently maintained. In order of im-
portance to navigation, the East and West Access Channels rank highest. The
East Freshwater Distribution Channel has by far the least number of traffic
occurrences.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
Water Traffic
Sediment Transport
River Basin Development
Atchafalaya Basin
13 J
08 H
13. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (This Report)
UNCLASSIFIED
21. NO. OF PAGES
40
2O. SECURITY CLASS (Thispage)
UNCLASSIFIED
22. PRICE
EPA Form 2220-1 (9-73)
*U. S. GOVERNMENT PRINTING OFFICE:. 1978-785-328
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