Draft Comprehensive Conservation Plan and Environmental Assessment Atchafalya National Wildlife Refuge

              DRAFT COMPREHENSIVE CONSERVATION PLAN
AND ENVIRONMENTAL ASSESSMENT
ATCHAFALAYA NATIONAL WILDLIFE REFUGE
St. Martin and Iberville Parishes, Louisiana
U.S. Department of the Interior
Fish and Wildlife Service
Southeast Region
Atlanta, Georgia
April 2011
Atchafalaya National Wildlife Refuge
Table of Contents i
TABLE OF CONTENTS
SECTION A. DRAFT COMPREHENSIVE CONSERVATION PLAN
I. BACKGROUND ................................................................................................................................ 1
Introduction .................................................................................................................................. 1
Purpose And Need For The Plan ................................................................................................. 1
Fish and Wildlife Service .............................................................................................................. 1
National Wildlife Refuge System .................................................................................................. 3
Legal and Policy Context .............................................................................................................. 5
National and International Conservation Plans and Initiatives ..................................................... 6
Relationship To State Wildlife Agency .......................................................................................... 7
II. REFUGE OVERVIEW ........................................................................................................................ 9
Introduction .................................................................................................................................. 9
Refuge History and Purpose ...................................................................................................... 11
Land Acquisition History .................................................................................................... 11
Purposes ........................................................................................................................... 11
Management Goals .................................................................................................................... 13
Special Designations .................................................................................................................. 13
Ecosystem Context ..................................................................................................................... 14
Lower Mississippi River Ecosystem .................................................................................. 14
Regional Conservation Plans and Initiatives .............................................................................. 17
Ecological Threats and Problems ...............................................................................................20
Atchafalaya Basin .............................................................................................................20
Forest Loss and Fragmentation Effects on Biological Diversity ........................................ 20
Alterations to Natural Hydrology and Wetlands ................................................................ 22
Non-Point Source Pollution and Siltation of Aquatic Ecosystems ..................................... 22
Proliferation of Invasive Aquatic Plants ............................................................................. 23
Oil and Gas Contaminant Activities ................................................................................... 23
Physical Resources .................................................................................................................... 23
Climate .............................................................................................................................. 23
Climate Change and Global Warming ............................................................................... 24
Geology and Topography .................................................................................................. 27
Soils ................................................................................................................................. 29
Hydrology and Water Quality ............................................................................................ 30
Air Quality .......................................................................................................................... 38
Biological Resources .................................................................................................................. 41
Habitat ............................................................................................................................... 41
Wildlife ...............................................................................................................................44
Cultural Resources ..................................................................................................................... 47
Socioeconomic Environment ...................................................................................................... 49
Regional Demographics and Economy ............................................................................. 49
Refuge Administration and Management ................................................................................... 50
Land Protection and Conservation .................................................................................... 50
Visitor Services ................................................................................................................. 53
Personnel, Operations, and Maintenance ......................................................................... 56
ii Atchafalaya National Wildlife Refuge
III. PLAN DEVELOPMENT .................................................................................................................. 57
Introduction ............................................................................................................................... 57
Summary of Issues, Concerns, and Opportunities ..................................................................... 57
Fish and Wildlife Population Management........................................................................ 58
Habitat Management......................................................................................................... 60
Resource Protection ......................................................................................................... 62
Visitor Services ................................................................................................................. 63
Refuge Administration ...................................................................................................... 64
IV. MANAGEMENT DIRECTION ....................................................................................................... 65
Introduction ............................................................................................................................... 65
Vision ........................................................................................................................................ 65
Goals, Objectives, and Strategies .............................................................................................. 65
Fish and Wildlife Population Management........................................................................ 66
Habitat Management......................................................................................................... 72
Visitor Services ................................................................................................................. 79
Resource Protection ......................................................................................................... 85
Refuge Administration ...................................................................................................... 88
V. PLAN IMPLEMENTATION ............................................................................................................ 91
Introduction ............................................................................................................................... 91
Proposed Projects ...................................................................................................................... 91
Fish and Wildlife Population Management........................................................................ 91
Habitat Management......................................................................................................... 93
Resource Protection ......................................................................................................... 94
Visitor Services ................................................................................................................. 95
Refuge Administration ...................................................................................................... 97
Funding and Personnel .............................................................................................................. 98
Partnership/Volunteer Opportunities .......................................................................................... 99
Step-Down Management Plans ................................................................................................ 100
Monitoring and Adaptive Management ..................................................................................... 100
Plan Review and Revision........................................................................................................ 101
SECTION B. ENVIRONMENTAL ASSESSMENT
I. BACKGROUND ............................................................................................................................. 103
Introduction .............................................................................................................................. 103
Purpose and Need for Action ................................................................................................... 103
Decision Framework................................................................................................................. 104
Planning Study Area ................................................................................................................ 104
Authority, Legal Compliance, and Compatibility ....................................................................... 104
Public Involvement and the Planning Process ......................................................................... 105
II. AFFECTED ENVIRONMENT ........................................................................................................ 107
Table of Contents iii
III. DESCRIPTION OF ALTERNATIVES ........................................................................................... 109
Formulation of Alternatives ....................................................................................................... 109
Description of Alternatives ........................................................................................................ 109
Alternative A – Current Management (No Action) ........................................................... 109
Alternative B – Optimize Biological and Visitor Services (Proposed Alternative) ............ 111
Alternative C – Maximize Public Use .............................................................................. 112
Features Common to all Atchafalaya NWR Alternatives .......................................................... 113
Comparison of the Alternatives by Issue .................................................................................. 114
Alternatives Considered But Eliminated From Further Analysis ............................................... 132
IV. ENVIRONMENTAL CONSEQUENCES ...................................................................................... 133
Overview .................................................................................................................................. 133
Effects Common to All Alternatives .......................................................................................... 133
Public Health and Safety ................................................................................................. 133
Environmental Justice ..................................................................................................... 133
Climate Change .............................................................................................................. 134
Regulatory Effects ........................................................................................................... 134
Land Acquisition ..............................................................................................................135
Cultural Resources .......................................................................................................... 135
Refuge Revenue Sharing ................................................................................................ 136
Visitor Services ............................................................................................................... 136
Refuge Administration ..................................................................................................... 136
Other Management ......................................................................................................... 136
Other Effects ................................................................................................................... 137
Summary of Effects by Alternative ........................................................................................... 137
Alternative A – Current Management (No Action) ........................................................... 137
Alternative B – Optimize Biological and Visitor Services (Proposed Alternative) ............ 139
Alternative C – Maximize Public Use .............................................................................. 140
Unavoidable Effects and Mitigation Measures ......................................................................... 174
Water Quality from Soil Disturbance and Use of Herbicides ........................................... 174
Wildlife Disturbance ........................................................................................................ 174
Vegetation Disturbance ................................................................................................... 175
User Group Conflicts ....................................................................................................... 175
Effects on Adjacent Landowners ..................................................................................... 175
Land Ownership and Site Development .......................................................................... 176
Cumulative Effects .................................................................................................................... 176
Direct and Indirect Effects ........................................................................................................ 178
Short-term Uses versus Long-term Productivity ....................................................................... 182
V. CONSULTATION AND COORDINATION .................................................................................... 185
Overview .................................................................................................................................. 185
Core Planning Team ....................................................................................................... 185
Biological Review Team .................................................................................................. 186
Visitor Services Review Team ........................................................................................ 186
iv Atchafalaya National Wildlife Refuge
APPENDICES
APPENDIX A. GLOSSARY .............................................................................................................. 187
APPENDIX B. REFERENCES AND LITERATURE CITATIONS .................................................... 197
APPENDIX C. RELEVANT LEGAL MANDATES AND EXECUTIVE ORDERS ............................. 205
APPENDIX D. PUBLIC INVOLVEMENT ......................................................................................... 219
Summary Of Public Scoping Comments .................................................................................. 219
APPENDIX E. APPROPRIATE USE DETERMINATIONS .............................................................. 223
Atchafalaya National Wildlife Refuge Appropriate Use Determinations ................................... 223
APPENDIX F. COMPATIBILITY DETERMINATIONS ..................................................................... 233
APPENDIX G. INTRA-SERVICE SECTION 7 BIOLOGICAL EVALUATION .................................. 253
APPENDIX H. WILDERNESS REVIEW ........................................................................................... 257
APPENDIX I. REFUGE BIOTA ........................................................................................................ 259
Birds ........................................................................................................................................ 259
Mammals ................................................................................................................................. 264
Reptiles and Amphibians.......................................................................................................... 265
Common Fish ........................................................................................................................... 268
Wildlife Species of Special Concern on Atchafalaya NWR ...................................................... 269
Commonly Occurring Vegetation on Atchafalaya NWR ........................................................... 270
Table of Contents v
LIST OF FIGURES
Figure 1. Location of Atchafalaya National Wildlife Refuge. ................................................................. 2
Figure 2. Sherburne Complex. ............................................................................................................ 10
Figure 3. Atchafalaya NWR Current Fee Title Lands and Acquisition Boundary. ............................... 12
Figure 4. Protected Lands within the Atchafalaya Basin Floodway System. ...................................... 16
Figure 5. Landscape Conservation Cooperatives and Atchafalaya National Wildlife Refuge. ............ 21
Figure 6. Generalized Geologic Map of Louisiana ..............................................................................28
Figure 7. General Habitat Types on Atchafalaya National Wildlife Refuge. ........................................ 42
LIST OF TABLES
Table 1. Climatological normals for the years 1971-2000 - Baton Rouge, LA
(Ryan Air Port Weather Station) ......................................................................................... 26
Table 2. Louisiana's major aquifers and aquifer systems ................................................................ 35
Table 3. Mississippi River alluvial aquifer water quality data FY2005.............................................. 37
Table 4. National ambient air quality standards ............................................................................... 39
Table 5. NAAQS ambient air monitoring data in the vicinity of Atchafalaya NWR ........................... 40
Table 6. Rare or imperiled plants in Iberville and/or St. Martin Parishes, Louisiana
according to the State of Louisiana’s Natural Heritage Program ...................................... 43
Table 7. Demographics and socioeconomics for the Atchafalaya NWR area ................................. 51
Table 8. Outdoor recreational economics in Louisiana by U.S. residents ....................................... 52
Table 9. Migrating and wintering waterfowl foraging habitat objectives established by
the LMVJV for Atchafalaya NWR ...................................................................................... 75
Table 10. Summary of projects .......................................................................................................... 98
Table 11. Atchafalaya NWR step-down management plans ........................................................... 100
Table 12. Comparison of alternatives by management issues for Atchafalaya NWR ...................... 114
Table 13. Summary of environmental effects by alternative, Atchafalaya NWR .............................. 142
vi Atchafalaya National Wildlife Refuge
Draft Comprehensive Conservation Plan 1
SECTION A. DRAFT COMPREHENSIVE CONSERVATION PLAN
I. Background
INTRODUCTION
This Draft Comprehensive Conservation Plan and Environmental Assessment (Draft CCP/EA) for
Atchafalaya National Wildlife Refuge (NWR), located in the Lower Atchafalaya Basin Floodway
System in St. Martin and Iberville Parishes, Louisiana (Figure 1), was prepared to guide management
actions and direction for the refuge. Fish and wildlife conservation will receive first priority in refuge
management. Wildlife-dependent recreation will be allowed and encouraged as long as it is
compatible with, and does not detract from, the mission of the refuge or the purposes for which it was
established.
A planning team developed a range of alternatives that best met the goals and objectives of the
refuge and that could be implemented within the 15-year planning period. This Draft CCP/EA
describes the U.S. Fish and Wildlife Service’s (Service) proposed plan, as well as other alternatives
considered and their effects on the environment. The Draft CCP/EA will be made available to state
and federal government agencies, conservation partners, and the general public for review and
comment. Comments from each entity will be considered in the development of the Final CCP.
PURPOSE AND NEED FOR THE PLAN
The purpose of the plan is to develop a proposed action that best achieves the refuge purpose;
attains the vision and goals developed for the refuge; contributes to National Wildlife Refuge System
(Refuge System) mission; addresses key problems, issues and relevant mandates; and is consistent
with sound principles of fish and wildlife management.
Specifically, the plan is needed to:
 Provide a clear statement of refuge management direction;
 Provide refuge neighbors, visitors, and government officials with an understanding of Service
management actions on and around the refuge;
 Ensure that Service management actions, including land protection and recreation/education
programs, are consistent with the mandates of the Refuge System; and
 Provide a basis for the development of budget requests for operations, maintenance, and
capital improvement needs.
FISH AND WILDLIFE SERVICE
The Service traces its roots to 1871 and the establishment of the Commission of Fisheries involved
with research and fish culture. The once-independent commission was renamed the Bureau of
Fisheries and placed under the Department of Commerce and Labor in 1903.
The Service also traces its roots to 1886 and the establishment of a Division of Economic Ornithology
and Mammalogy in the Department of Agriculture. Research on the relationship of birds and animals
to agriculture shifted to delineation of the range of plants and animals so the name was changed to
the Division of the Biological Survey in 1896.
2 Atchafalaya National Wildlife Refuge
Figure 1. Location of Atchafalaya NWR
Draft Comprehensive Conservation Plan 3
The Department of Commerce, Bureau of Fisheries, was combined with the Department of
Agriculture, Bureau of Biological Survey, on June 30, 1940, and transferred to the Department of the
Interior as the Fish and Wildlife Service. The name was changed to the Bureau of Sport Fisheries
and Wildlife in 1956 and finally to the Fish and Wildlife Service in 1974.
The Fish and Wildlife Service, working with others, is responsible for conserving, protecting, and
enhancing fish and wildlife and their habitats for the continuing benefit of the American people
through Federal programs relating to migratory birds, endangered species, interjurisdictional fish and
marine mammals, and inland sport fisheries (142 DM 1.1).
As part of its mission, the Service manages more than 540 national wildlife refuges covering over
95 million acres. These areas comprise the National Wildlife Refuge System, the world’s largest
collection of lands set aside specifically for fish and wildlife. The majority of these lands, 77 million
acres, is in Alaska. The remaining acres are spread across the other 49 states and several United
States territories. In addition to refuges, the Service manages thousands of small wetlands,
national fish hatcheries, 64 fishery resource offices, and 78 ecological services field stations. The
Service enforces federal wildlife laws, administers the Endangered Species Act, manages migratory
bird populations, restores nationally significant fisheries, conserves and restores wildlife habitat,
and helps foreign governments with their conservation efforts. It also oversees the Federal Aid
program that distributes hundreds of millions of dollars in excise taxes on fishing and hunting
equipment to state fish and wildlife agencies.
NATIONAL WILDLIFE REFUGE SYSTEM
The mission of the National Wildlife Refuge System, as defined by the National Wildlife Refuge
System Improvement Act of 1997 is:
“...to administer a national network of lands and waters for the conservation,
management, and where appropriate, restoration of the fish, wildlife and plant resources
and their habitats within the United States for the benefit of present and future
generations of Americans.”
The National Wildlife Refuge System Improvement Act of 1997 (Improvement Act) established, for the
first time, a clear legislative mission of wildlife conservation for the Refuge System. Actions were
initiated in 1997 to comply with the direction of this new legislation, including an effort to complete
comprehensive conservation plans for all refuges. These plans, which are completed with full public
involvement, help guide the future management of refuges by establishing natural resources and
recreation/education programs. Consistent with the Improvement Act, approved plans will serve as
the guidelines for refuge management for the next 15 years. The Improvement Act states that each
refuge shall be managed to:
 Fulfill the mission of the Refuge System;
 Fulfill the individual purposes of each refuge;
 Consider the needs of wildlife first;
 Fulfill requirements of comprehensive conservation plans that are prepared for each unit of
the Refuge System;
 Maintain the biological integrity, diversity, and environmental health of the Refuge System;
and
4 Atchafalaya National Wildlife Refuge
 Recognize that wildlife-dependent recreation activities including hunting, fishing, wildlife
observation, wildlife photography, and environmental education and interpretation are
legitimate and priority public uses; and allow refuge managers authority to determine
compatible public uses.
The following are just a few examples of your national network of conservation lands. Pelican Island
NWR, the first refuge, was established in 1903 for the protection of colonial nesting birds in Florida, such
as the snowy egret and the brown pelican. Western refuges were established for American bison (1906),
elk (1912), prong-horned antelope (1931), and desert bighorn sheep (1936) after over-hunting,
competition with cattle, and natural disasters decimated once-abundant herds. The drought conditions of
the 1930s Dust Bowl severely depleted breeding populations of ducks and geese. Refuges established
during the Great Depression focused on waterfowl production areas (i.e., protection of prairie wetlands in
America’s heartland). The emphasis on waterfowl continues today but also includes protection of
wintering habitat in response to a dramatic loss of bottomland hardwoods. By 1973, the Service had
begun to focus on establishing refuges for endangered species.
Approximately 38 million people visited national wildlife refuges in 2002, most to observe wildlife in
their natural habitats. As the number of visitors grows, there are significant economic benefits to local
communities. In 2001, 82 million people, 16 years and older, fished, hunted, or observed wildlife,
generating $108 billion. In a study completed in 2002 on 15 refuges, visitation had grown 36 percent
in 7 years. At the same time, the number of jobs generated in surrounding communities grew to 120
per refuge, up from 87 jobs in 1995, pouring more than $2.2 million into local economies. The 15
refuges in the study were Chincoteague (Virginia); National Elk (Wyoming); Crab Orchard (Illinois);
Eufaula (Alabama); Charles M. Russell (Montana); Umatilla (Oregon); Quivira (Kansas);
Mattamuskeet (North Carolina); Upper Souris (North Dakota); San Francisco Bay (California); Laguna
Atacosa (Texas); Horicon (Wisconsin); Las Vegas (Nevada); Tule Lake (California); and Tensas River
(Louisiana) – the same refuges identified for the 1995 study. Other findings also validate the belief
that communities near refuges benefit economically. Expenditures on food, lodging, and
transportation grew to $6.8 million per refuge, up 31 percent from $5.2 million in 1995. For each
dollar spent on the Refuge System, surrounding communities benefited with $4.43 in recreation
expenditures and $1.42 in job-related income (Caudill and Laughland, unpubl. data).
Volunteers continue to be a major contributor to the success of the Refuge System. In 2002,
volunteers contributed more than 1.5 million hours on refuges nationwide, a service valued at more
than $22 million.
The wildlife and habitat vision for national wildlife refuges stresses that wildlife comes first; that
ecosystems, biodiversity, and wilderness are vital concepts in refuge management; that refuges must
be healthy and growth must be strategic; and that the Refuge System serves as a model for habitat
management with broad participation from others.
The Improvement Act stipulates that comprehensive conservation plans be prepared in consultation
with adjoining federal, state, and private landowners and that the Service develop and implement a
process to ensure an opportunity for active public involvement in the preparation and revision (every
15 years) of the plans.
All lands of the Refuge System will be managed in accordance with an approved comprehensive
conservation plan that will guide management decisions and set forth strategies for achieving refuge
unit purposes. The plan will be consistent with sound resource management principles, practices,
and legal mandates, including Service compatibility standards and other Service policies, guidelines,
and planning documents (602 FW 1.1).
Draft Comprehensive Conservation Plan 5
LEGAL AND POLICY CONTEXT
Legal Mandates, Administrative and Policy Guidelines, and Other Special Considerations
Administration of national wildlife refuges is guided by the mission and goals of the Refuge System,
congressional legislation, presidential executive orders, and international treaties. Policies for
management options of refuges are further refined by administrative guidelines established by the
Secretary of the Interior and by policy guidelines established by the Director of the Fish and Wildlife
Service. Select legal summaries of treaties and laws relevant to administration of the Refuge System
and management of the Atchafalaya NWR are provided in Appendix C.
Treaties, laws, administrative guidelines, and policy guidelines assist the refuge manager in making
decisions pertaining to soil, water, air, flora, fauna, and other natural resources; historical and cultural
resources; research and recreation on refuge lands; and provide a framework for cooperation between
Atchafalaya NWR and other partners, such as the Louisiana Department of Wildlife and Fisheries,
National Park Service, Audubon Society, Friends of Louisiana Wildlife Refuges, Army Corps of
Engineers, corporations, and private landowners, etc.
Lands within the Refuge System are closed to public use unless specifically and legally opened. No
refuge use may be allowed unless it is determined to be compatible. A compatible use is a use that,
in the sound professional judgment of the refuge manager, will not materially interfere with, or detract
from, the fulfillment of the mission of the Refuge System or the purposes of the refuge. All programs
and uses must be evaluated based on mandates set forth in the Improvement Act. Those mandates
are to:
 Contribute to ecosystem goals, as well as refuge purposes and goals;
 Conserve, manage, and restore fish, wildlife, and plant resources and their habitats;
 Monitor the trends of fish, wildlife, and plants;
 Manage and ensure appropriate visitor uses as those uses benefit the conservation of fish
and wildlife resources and contribute to the enjoyment of the public; and
 Ensure that visitor activities are compatible with refuge purposes.
The Improvement Act further identifies six priority wildlife-dependent recreational uses. These uses
are: hunting, fishing, wildlife observation, wildlife photography, and environmental education and
interpretation. As priority public uses of the Refuge System, they receive priority consideration over
other public uses in planning and management.
Biological Integrity, Diversity, and Environmental Health Policy
The Improvement Act directs the Service to ensure that the biological integrity, diversity, and
environmental health of the Refuge System are maintained for the benefit of present and future
generations of Americans. The policy is an additional directive for refuge managers to follow while
achieving refuge purpose(s) and the Refuge System mission. It provides for the consideration and
protection of the broad spectrum of fish, wildlife, and habitat resources found on refuges and
associated ecosystems. When evaluating the appropriate management direction for refuges, refuge
managers will use sound professional judgment to determine their refuges’ contribution to biological
integrity, diversity, and environmental health at multiple landscape scales. Sound professional
judgment incorporates field experience, knowledge of refuge resources and role within the
ecosystem, applicable laws, and best available science, including consultation with others both inside
and outside the Service.
6 Atchafalaya National Wildlife Refuge
NATIONAL AND INTERNATIONAL CONSERVATION PLANS AND INITIATIVES
Multiple partnerships have been developed among government and private entities to address the
environmental problems affecting regions. There is a large amount of conservation and protection
information that defines the role of the refuge at local, national, international, and ecosystem levels.
Conservation initiatives include broad-scale planning and cooperation between affected parties to
address declining trends of natural, physical, social, and economic environments. The conservation
guidance described below, along with issues, problems, and trends, was reviewed and integrated
where appropriate into this Draft CCP/EA.
This Draft CCP/EA supports, among others, the Partners-in-Flight Plan, the North American
Waterfowl Management Plan, the Western Hemisphere Shorebird Reserve Network, and the National
Wetlands Priority Conservation Plan.
North American Bird Conservation Initiative. Started in 1999, the North American Bird
Conservation Initiative is a coalition of government agencies, private organizations, academic
institutions, and private industry leaders in the United States, Canada, and Mexico working to ensure
the long-term health of North America's native bird populations by fostering an integrated approach to
bird conservation to benefit all birds in all habitats. The four international and national bird initiatives
include the North American Waterfowl Management Plan, Partners-in-Flight, Waterbird Conservation
for the Americas, and the U.S. Shorebird Conservation Plan.
North American Waterfowl Management Plan. The North American Waterfowl Management Plan
is an international action plan to conserve migratory birds throughout the continent. The plan's goal is
to return waterfowl populations to their 1970s levels by conserving wetland and upland habitat.
Canada and the United States signed the plan in 1986 in reaction to critically low numbers of
waterfowl. Mexico joined in 1994, making it a truly continental effort. The plan is a partnership of
federal, provincial/state and municipal governments, non-governmental organizations, private
companies, and many individuals, all working towards achieving better wetland habitat for the benefit
of migratory birds, other wetland-associated species, and people. Plan projects are international in
scope, but implemented at regional levels. These projects contribute to the protection of habitat and
wildlife species across the North American landscape.
Partners-in-Flight Bird Conservation Plan. Managed as part of the Partners-in-Flight Plan, the
Mississippi Alluvial Valley (MAV) physiographic area represents a scientifically based land bird
conservation planning effort that ensures long-term maintenance of healthy populations of native land
birds, primarily non-game land birds. Non-game land birds have been vastly under-represented in
conservation efforts, and many are exhibiting significant declines. This plan is voluntary and non-regulatory,
and focuses on relatively common species in areas where conservation actions can be
most effective, rather than the frequent local emphasis on rare and peripheral populations.
U.S. Shorebird Conservation Plan. The U.S. Shorebird Conservation Plan is a partnership effort
throughout the United States to ensure that stable and self-sustaining populations of shorebird
species are restored and protected. The plan was developed by a wide range of agencies,
organizations, and shorebird experts for separate regions of the country, and identifies conservation
goals, critical habitat conservation needs, key research needs, and proposed education and outreach
programs to increase awareness of shorebirds and the threats they face.
Draft Comprehensive Conservation Plan 7
Northern American Waterbird Conservation Plan. This plan provides a framework for the
conservation and management of 210 species of waterbirds in 29 nations. Threats to waterbird
populations include destruction of inland and coastal wetlands, introduced predators and invasive
species, pollutants, mortality from fisheries and industries, disturbance, and conflicts arising from
abundant species. Particularly important habitats of the southeast region include pelagic areas,
marshes, forested wetlands, and barrier and sea island complexes. Fifteen species of waterbirds are
federally listed, including breeding populations of wood storks, Mississippi sandhill cranes, whooping
cranes, and interior least terns. A key objective of this plan is the standardization of data collection
efforts to better recommend effective conservation measures.
RELATIONSHIP TO STATE WILDLIFE AGENCY
A provision of the Improvement Act, and subsequent agency policy, is that the Service shall ensure
timely and effective cooperation and collaboration with state fish and game agencies and tribal
governments during the course of acquiring and managing refuges. State wildlife management areas
and national wildlife refuges provide the foundation for the protection of species, and contribute to the
overall health and sustainment of fish and wildlife species in the State of Louisiana.
The Louisiana Department of Wildlife and Fisheries (LDWF) (http://www.wlf.louisiana.gov) is vested
with responsibility for the conservation and management of wildlife in the state, including aquatic life,
and is authorized to execute the laws enacted for the control and supervision of programs relating to the
management, protection, conservation, and replenishment of wildlife, fish, and aquatic life, and the
regulation of the shipping of wildlife fish, furs, and skins. LDWF’s mission is to manage, conserve, and
promote wise utilization of Louisiana’s renewable fish and wildlife resources and their supporting
habitats through replenishment, protection, enhancement, research, development, and education for
the social and economic benefit of current and future generations; to provide opportunities for
knowledge of and use and enjoyment of these resources; and to promote a safe and healthy
environment for the users of the resources. LDWF is divided into four divisions for management of the
state’s resources: Coastal and Nongame Resources, Fisheries, Enforcement, and Wildlife.
Public access on all refuge lands is currently managed by the LDWF under Cooperative Agreement
No. 1416000486946. Since the federal and state lands share common boundaries, LDWF technical
and field personnel manage the wildlife on both the wildlife management areas and the refuge.
Service personnel are responsible for all forest management, law enforcement, and issuance of
special use permits. The Atchafalaya NWR (Service), Bayou Des Ourses Area (USACE), and
Sherburne Wildlife Management Area (LDWF), are collectively referred to as the Sherburne Complex.
The state’s participation and contribution throughout this planning process will provide for ongoing
opportunities and open dialogue to improve the ecological sustainment of fish and wildlife in the State
of Louisiana. An essential part of comprehensive conservation planning is integrating common
mission objectives where appropriate.
8 Atchafalaya National Wildlife Refuge
Draft Comprehensive Conservation Plan 9
II. Refuge Overview
INTRODUCTION
Atchafalaya NWR is located in the lower Atchafalaya Basin Floodway System in St. Martin and
Iberville Parishes, Louisiana. The name originated from its location within the Atchafalaya River
Basin. Atchafalaya NWR is bounded on the north by U.S. Highway 190, on the south by Interstate
10, on the west by the Atchafalaya River, and on the east by the East Atchafalaya Basin Protection
Levee (Figure 1). Atchafalaya NWR is part of the Southeast Louisiana NWR Complex.
Atchafalaya NWR was established in 1986, when 15,255 acres were purchased from the Iberville
Land Company, as directed by Public Law 98-548. The LDWF and the USACE have also purchased
fee title land adjacent to and within the Atchafalaya NWR, which brings the current acreage among all
three agencies (LDWF, Service, and USACE) to approximately 44,000. The USACE has authority to
purchase additional lands within the Atchafalaya Basin Floodway.
All three agencies’ public access lands are managed by the LDWF under Cooperative Agreements.
The Service operates under Contract No. 1416000486946. Since the federal and state lands share
common boundaries, LDWF technical and field personnel manage the wildlife on both the wildlife
management area and the refuge. Service personnel are responsible for all forest management, law
enforcement, and issuance of special use permits. The Atchafalaya NWR, Bayou Des Ourses Area
(USACE), and Sherburne Wildlife Management Area (LDWF), are collectively referred to as the
Sherburne Complex (Figure 2).
Approximately 12 percent of the refuge is inundated open water, with isolated cypress trees and
willow stands. Bottomland hardwood forest is the primary habitat. Self-guided tours can be accessed
by auto, boat, or foot. Traditional use of the area is hunting and fishing, which follows the state's
annual season dates and specific regulations. Camping is allowed nearby on the Sherburne Wildlife
Management Area.
The bottomland hardwood forests in the area of Atchafalaya NWR have four dominant tree species
associations: cottonwood-sycamore; oak-gum-sugarberry-ash; willow-cypress-ash; and, overcup oak-bitter
pecan. Mid-story species encompass seedlings of dominant species along with boxelder,
maple, red mulberry, and rough-leaf dogwood. Ground cover is sparse, in areas, due to shading out
and prolonged inundation. In those areas where habitat improvement, through the practice of forest
management, has taken place, the ground cover is very dense and provides excellent habitat for
many game and non-game wildlife species. Common groundcover species found include rattan,
greenbriar, rubus, trumpet creeper, Virginia creeper, poison ivy, and milkweed. Much of the area
supports lush stands of fern (Louisiana Department of Wildlife and Fisheries 2005a).
10 Atchafalaya National Wildlife Refuge
Figure 2. Sherburne Wildlife Management Area Complex
Draft Comprehensive Conservation Plan 11
REFUGE HISTORY AND PURPOSE
LAND ACQUISITION HISTORY
The LDWF purchased 11,780 acres on September 13, 1983, and created the Sherburne Wildlife
Management Area. In the 1984 Supplemental Appropriations Act (Public Law 98-396), passed by
Congress and signed into law by President Reagan, a total of $10 million from the Land and Water
Conservation Fund was appropriated to the Service to acquire lands and waters in the Atchafalaya
River Basin in accordance with statutory authority applicable to the Fish and Wildlife Act of 1956 (see
below). Subsequently, in 1986, the Service purchased 15,220 acres from the Iberville Land
Company with these funds and established Atchafalaya NWR.
Since 1989, the USACE has also purchased 17,000 acres of fee title land adjacent to and within
the Atchafalaya NWR current acquisition boundary (Figure 3), which brings the current
concomitant acreage among all three agencies (LDWF, Service, and USACE) to approximately
44,000 (Figure 2). The Sherburne Complex is managed cooperatively with LDWF's Sherburne
Wildlife Management Area and the USACE's Atchafalaya Basin Floodway System, Louisiana
Project. Since the federal and state lands share common boundaries, LDWF technical and field
personnel manage the wildlife on both the wildlife management area and the refuge on a day-to-day
basis. Service personnel are responsible for all forest management and issuance of special
use permits. (Sources: USFWS 2008a, 2008b, and 2009a; Federal Register 2009)
PURPOSES
The purposes shown here are based upon land acquisition documents and authorities. The refuge
purposes may also include purposes included as deed restrictions, management agreements with
primary land managers, and congressionally established wilderness designations which were not part
of the acquisition documents and authorities.
On October 26, 1984, Congress authorized the establishment of Atchafalaya NWR (Public Law 98-
548) for the following purposes:
(1) To provide for the conservation and management of fish and wildlife within the refuge;
(2) To fulfill the international treaty obligations of the United States with respect to fish and
wildlife; and
(3) To provide opportunities for scientific research, environmental education, and fish and
wildlife-oriented recreation, including hunting, fishing, and trapping, bird watching, nature
photography, and others.
Additionally, the earlier Fish and Wildlife Act of 1956, authorized the establishment of national wildlife
refuges "for the development, advancement, management, conservation, and protection of fish and
wildlife resources" [16 U.S.C. 742f(a)(4)] and "for the benefit of the United States Fish and Wildlife
Service, in performing its activities and services. Such acceptance may be subject to the terms of
any restrictive or affirmative covenant, or condition of servitude" [16 U.S.C. 742f(b)(1) (Fish and
Wildlife Act of 1956)].
12 Atchafalaya National Wildlife Refuge
Figure 3. Atchafalaya NWR current fee title lands and acquisition boundary
Draft Comprehensive Conservation Plan 13
MANAGEMENT GOALS
The nine current management objectives of Atchafalaya NWR are to:
 Manage the refuge in a manner that will conserve the natural state of the floodway system,
consistent with the public harvest of the surplus wildlife resources and protection of rare and
endangered species.
 Provide habitat and protection for threatened and endangered species
 Provide habitat for wildlife and plant species of special concern.
 Provide, enhance, and maintain habitat meeting the requirements of all wildlife, while providing for
wildlife diversity.
 Provide migrating and wintering habitat for migratory waterfowl and other migratory birds;
 Provide compatible recreation, environmental education, scientific research, and interpretive/
demonstration activities.
 Provide areas for quality observation of wildlife in their native habitats.
 Provide demonstration areas for exhibition of sound habitat and wildlife management practices.
 Protect refuge resources, visitors, and facilities while providing compatible public outdoor
recreation opportunities.
SPECIAL DESIGNATIONS
Natural Areas
No natural areas have been designated on the Atchafalaya NWR. If any unique habitats or ecosystems
are identified, they will be considered for designation or otherwise be protected. In order to meet
criteria for a natural area, an area must have some unique or otherwise valuable characteristic which
will perpetuate itself. Consequently, old growth forests, while very valuable to particular species of
wildlife, are changing and will not maintain present conditions (Boykin 1990).
Wilderness Review
Currently, there are no areas of special designation on Atchafalaya NWR. However, refuge planning
policy requires a wilderness review as part of the comprehensive conservation planning process. The
Wilderness Act of 1964 defines a wilderness area as an area of federal land that retains its primeval
character and influence, without permanent improvements or human inhabitation, and is managed so
as to preserve its natural condition, which generally appears to have been influenced primarily by the
forces of nature, with the imprint of man’s work substantially unnoticeable; has outstanding
opportunities for solitude or primitive and unconfined type of recreation; has at least 5,000 contiguous
roadless acres, or is of sufficient size to make practicable its preservation and use in an unimpeded
condition, or is a roadless island regardless of size; does not substantially exhibit the effects of logging,
farming, grazing, or other extensive development or alteration of the landscape, or its wilderness
character could be restored through appropriate management at the time of review; and may contain
ecological, geological, or other features of scientific, educational, scenic, or historic value.
Lands within the Atchafalaya NWR were reviewed for their suitability in meeting the criteria for
Wilderness Areas, as defined by the Wilderness Act of 1964. No areas were found to meet these
criteria. Therefore, the suitability of refuge lands for wilderness designation is not further analyzed in
this Draft CCP/EA.
14 Atchafalaya National Wildlife Refuge
Critical Habitat
The Service has designated critical habitat for the Louisiana black bear in the State of Louisiana. On
March 10, 2009, the Service designated 1,195,821 acres of critical habitat in Avoyelles, East Carroll,
Catahoula, Concordia, Franklin, Iberia, Iberville, Madison, Pointe Coupee, Richland, St. Martin, St.
Mary, Tensas, West Carroll, and West Feliciana Parishes, Louisiana. Critical habitat is a term used in
the Endangered Species Act (ESA) that refers to specific geographic areas that are essential for the
conservation of a threatened or endangered species and that may require special management or
protection. The Louisiana black bear was listed as a threatened species under the ESA in 1992.
Other
The refuge has been identified as a Globally Important Bird Area by the American Bird Conservancy
and an "Important Bird Area" by the National Audubon Council. The bottomland hardwood forests
and the mix of bayous, oxbow lakes, sloughs, and swamps create a diversity of habitats important to
a wide range of bird species. Neotropical migratory birds abound during the fall and spring
migrations, and many species nest on the refuge. The refuge supports a number of small wading
bird rookeries. Each winter, several thousand waterfowl make their home on the refuge. The wood
duck is a common summer nester on the refuge.
Although Louisiana's Natural and Scenic River System is one of the nations' largest, oldest, and most
diverse, none of the streams or rivers in the Atchafalaya Basin is designated as such. However, a
National Wild and Scenic River designation for the Atchafalaya River and the waterways within the basin
is being proposed by the Delta Chapter of the Sierra Club (Sierra Club 2009).
Atchafalaya NWR does not contain any other lands under special designation by the Federal
Government, such as demonstration areas or research natural areas. However, (GAO-03-517)
Report on Oil and Gas on Wildlife Refuges, lists 35 inactive wells and pipelines and 2 active wells, in
addition to exploration activities ongoing at Atchafalaya NWR (U.S. General Accounting Office 2003).
ECOSYSTEM CONTEXT
LOWER MISSISSIPPI RIVER ECOSYSTEM
An ecosystem is a geographical area that includes and interconnects all the living (biotic) organisms,
and their physical (abiotic) surroundings, and the natural cycles that sustain them. All of these
elements are interconnected. Managing any one resource affects the others in that ecosystem.
Ecosystems can be small (a single stand of bottomland hardwoods) or large (an entire watershed
including hundreds of forest stands across many different ownerships).
The Mississippi Alluvial Valley (MAV) (also referred to as the Mississippi Alluvial Plain) was at one time
a 25-million-acre, forested wetland complex that extended along the Mississippi River from the
confluence of the Ohio and Mississippi Rivers southward to the Gulf of Mexico, before as much as 80
percent was cleared and drained for cultivation. The MAV is a broad, nearly level, now agriculturally
dominated alluvial plain. It is veneered by Quaternary alluvium, loess, glacial outwash, and lacustrine
deposits. River terraces, swales, and levees provide limited topographic relief. Nearly flat, clayey,
poorly drained soils are widespread and characteristic. Streams and rivers have very low gradients and
fine-grained substrates. Many reaches have ill-defined stream channels. The MAV provides important
habitat for fish and wildlife, and includes the largest continuous system of wetlands in North America. It
is also a major bird migration corridor used in fall and spring migrations. Potential natural vegetation is
largely southern floodplain forest and is unlike the oak–hickory and oak–hickory–pine forests that
Draft Comprehensive Conservation Plan 15
dominate upland areas. The MAV has been widely cleared and drained for cultivation; this widespread
loss or degradation of forest and wetland habitat has impacted wildlife and reduced bird populations.
Fish communities in least altered streams typically have an insignificant proportion of sensitive species;
sunfishes are dominant followed by minnows. Man-made flood control levees, in effect, separate the
river and its adjoining habitat from the remainder of its natural hydrologic system; in so doing, they
interfere with sediment transfer and have reduced available habitat for many species.
The Atchafalaya River Basin drains the lower portions of the MAV as the alluvial plain transitions to a
deltaic plain (Figure 4). This region marks a transition from the freshwater areas at the northern
extent of intra-tidal basins (freshwater back swamps) to the more brackish and saline areas of the
southern coastal marshes. The natural floodplain of the Atchafalaya River flows for about 140 miles
south from its junction with the Mississippi River to the Gulf of Mexico and contains over one-half
million acres of hardwood swamps, lakes, and bayous. The natural vegetation of swamp forest
communities is dominated by bald cypress and tupelo gum, which are generally intolerant of brackish
water except for short periods. In areas where freshwater flooding is more prolonged, the vegetation
community is dominated by grasses, sedges, and rushes. This region contains the largest
bottomland hardwood forest, freshwater swamps in North America. Deposits include organic clays
and peats, up to 20 feet thick, and inter-bedded freshwater and brackish-water carbonaceous clays.
The Atchafalaya River Basin is well-defined by a system of levees which surround it on the north,
east, and west. The entire basin serves as a major floodway for the Mississippi River floodwaters.
The Atchafalaya River presently carries about 30 percent of the combined flow of the Red and
Mississippi Rivers. The levees extend almost the full length of the Atchafalaya River. The levees in
the upper portion of the Atchafalaya Basin form two floodways which parallel the river. Atchafalaya
NWR is located in the east floodway. The refuge is characterized by bottomland hardwoods and
wetlands (characterized by cottonwood, sycamore, willow, and cypress/tupelo forests). Common tree
species on the higher, well-drained sites include red oak, sugarberry, sweetgum, and elm. The
wetter, lower sites contain predominantly cypress, willow, and ash. Other common species found in
association within these forest types include red maple, cottonwood, sycamore, locust, box elder, and
bitter pecan. The refuge serves as a primary wintering habitat for mid-continent waterfowl
populations, as well as breeding and migrating habitat for migratory songbirds. The expansive
floodplain forests of the past are now fragmented bottomland hardwood patches due to conversion to
agriculture and flood control projects (Chapman et al. 2009, Lester et al. 2005, and USFWS 2009b).
The Service’s Lower Mississippi River Ecosystem Team has eight goals (Chandler et al. 2002):
Resource Goals: The first five goals address the primary living natural resources and their habitats of
concern to the Service in the Lower Mississippi River Ecosystem.
 Conserve, enhance, protect, and monitor migratory bird populations and their habitats
in the Lower Mississippi River Ecosystem.
 Protect, restore, and manage the wetlands of the Lower Mississippi River Ecosystem.
 Protect and/or restore imperiled habitats and viable populations of all endangered,
threatened, and candidate species and species of concern in the Lower Mississippi
River Ecosystem.
 Protect, restore, and manage the fisheries and other aquatic resources historically
associated with the wetlands and waters of the Lower Mississippi River Ecosystem.
 Restore, manage, and protect National Wildlife Refuges and National Fish Hatcheries.
16 Atchafalaya National Wildlife Refuge
Figure 4. Protected lands within the Atchafalaya Basin Floodway System
Draft Comprehensive Conservation Plan 17
Support Goals: The following goals support the accomplishment of all five goals listed above:
wetlands, migratory birds, endangered species, fisheries, and Service lands. The support goals
are essential to the overall accomplishment of our mission, but do not fit entirely within any one of
the five resource goals.
 Increase public awareness and support for Lower Mississippi River Ecosystem
resources and their management.
 Enforce natural resource laws.
 Protect, restore, and enhance water and air quality throughout the Lower Mississippi
River Ecosystem.
REGIONAL CONSERVATION PLANS AND INITIATIVES
The mission of the Refuge System is to administer a national network of lands and waters for the
conservation, management, and where appropriate, restoration of the fish, wildlife, and plant resources
and their habitats within the United States for the benefit of present and future generations of Americans.
Comprehensive conservation plans are being prepared to provide each of the refuge managers with a 15-
year strategy and broad direction; to conserve wildlife and their habitats; to achieve refuge purposes; and,
to contribute toward the mission of the Refuge System. In addition, the plans identify wildlife-dependent
opportunities available to the public, including opportunities for hunting, fishing, wildlife observation,
wildlife photography, and environmental education and interpretation.
There are eight national wildlife refuges in the Service’s Southeast Louisiana National Wildlife Refuge
Complex. These are:
Atchafalaya NWR
Bayou Sauvage NWR
Bayou Teche NWR
Big Branch March NWR
Bogue Chitto NWR
Breton NWR
Delta NWR
Mandalay NWR
Atchafalaya NWR is considered to be in the MAV Bird Conservation Area. As such, Atchafalaya NWR is
a component of the following regional and ecosystem conservation planning initiatives in addition to the
national and international conservations plans listed in Chapter I.
American Woodcock Management Plan
This plan was written by the Service in 1990 to “guide the conservation of woodcock in the United
States.” The plan’s objective is to protect and enhance wintering and migrating habitat by developing
and implementing forest management plans that provide moist mid-story and ground-story vegetation
(thickets) in forested lands for daytime cover and foraging habitat and open nocturnal foraging habitat
in moist croplands and grassland habitats near scrub/shrub areas. Although no step-down plans
have been written, the plan gives general guidance for habitat population management at the national
level. Woodcock populations within the central region of the eastern United States have declined 19
percent since 1968, probably due to land use changes associated with land conversion and the
maturing of forest habitats.
18 Atchafalaya National Wildlife Refuge
Lower Mississippi River Ecosystem Plan
The “Lower Mississippi River Ecosystem Plan” seeks to enhance, restore, and conserve the natural
functional processes and habitat types of the Lower Mississippi River Ecosystem (LMRE) unit, while
maintaining the economic productivity and recreational opportunities of the region (Chandler et al.
2002). Objectives of this plan are to take actions to achieve existing population and habitats goals for
all migratory birds. These goals are contained in the MAV Migratory Bird Plan (Twedt 1999).
The Lower Mississippi Valley Joint Venture is a self-directed, non-regulatory private, state, and
federal conservation partnership that exists for the purpose of implementing the goals and
objectives of national and international bird conservation plans within the Lower Mississippi
Valley (LMV) region. The Lower Mississippi Valley Joint Venture (LMVJV) will function as the
forum in which the private, state, and federal conservation community develops a shared vision of
bird conservation for the LMV region; cooperates in its implementation; and collaborates in its
refinement. The LMVJV partnership is focused on the protection, restoration, and management
of those species of North American avifauna and their habitats (endemic to the LMV Region),
lying entirely or mostly within the MAV and West Gulf Coastal Plain (Lower Mississippi Valley
Joint Venture 2009]).
Louisiana's Comprehensive Wildlife Conservation Strategy
Two federal funding programs, the Wildlife Conservation and Restoration Program (WCRP) and the State
Wildlife Grants Program (SWG) resulted in the State of Louisiana developing a Comprehensive Wildlife
Conservation Strategy (CWCS). In December 2005, the LDWF, as part of its mission to manage, conserve,
and promote wise utilization of Louisiana’s fish and wildlife resources and their supporting habitats, released
its Comprehensive Wildlife Conservation Strategy (Wildlife Action Plan). The conservation actions and
strategies were developed in public focus groups held across the state with invited conservation
organizations, forestry and wildlife associations, federal and state agencies, industry, universities, and
private citizens. The intent of the robust plan is to guide the conservation efforts of the LDWF over a 10-
year period (Lester et al. 2005).
Atchafalaya Basin Program
The LDNR oversees the management of the state master plan for the Atchafalaya Basin Floodway
System. The Atchafalaya Basin Program (ABP) operates under the authority of Act 3 of 1998 and
Act 920 of 1999. LDNR, USACE, and the basin parishes work together in creating projects by
executing cooperative endeavors or agreements that protect and enhance the basin. Several other
state agencies, like the departments of Wildlife and Fisheries and Culture, Recreation and Tourism,
also work to establish projects aimed at enhancing the basin (Louisiana Department of Natural
Resources 2009). One of the ABP's most important projects, particularly as it relates to Atchafalaya
NWR, is the Sherburne Freshwater Diversion Structure at Big Alabama Bayou. This project was
authorized by the Water Resource Development Act of 1986 in accordance with the plan
recommended in the February 1983 Chief’s Report. The plan included construction of freshwater
distribution structures from the Atchafalaya River to provide water inflow into the Alabama Bayou
area. To date, no funds have been budgeted for or allocated to this effort by the USACE; however,
the ABP is actively working with the USACE New Orleans District to move this project forward
(Louisiana Department of Natural Resources 2009).
Mississippi Embayment Regional Aquifer Study
As part of the USGS Ground-Water Resources Program, a ground-water flow model of the northern
Mississippi embayment will be developed using data and knowledge gained from the Gulf Coast
Regional Aquifer System Analysis studies and other more recently completed USGS models to aid in
answering questions about ground-water availability. The proposed study area covers portions of
seven states including Arkansas, Louisiana, Mississippi, Tennessee, Alabama, Missouri, and
Draft Comprehensive Conservation Plan 19
Kentucky. The rectangular model grid will cover almost 158,000 square miles, while the active
portion to be simulated will cover approximately 70,000 square miles (U.S. Geological Survey 2007).
Southeast Aquatic Resources Partnership
The Southeast Aquatic Resources Partnership (SARP) includes fish and wildlife agencies from 14
southeastern States (Alabama, Arkansas, Florida, Georgia, Kentucky, Louisiana, Mississippi,
Missouri, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, and Virginia); the Gulf and
Atlantic States Marine Fisheries Commissions; the Gulf of Mexico and South Atlantic Fishery
Management Councils; the Service; and NOAA Fisheries. The SARP focuses on six key issue areas:
Aquatic Habitat Conservation; Public Use; Imperiled Fish and Aquatic Species Recovery; Fishery
Mitigation; Interjurisdictional Fisheries; and Aquatic Nuisance Species. These partnering entities
work together for the conservation and management of aquatic resources in the southeast (Southeast
Aquatic Resources Partnership 2009).
The Louisiana Native Plant Initiative and the Emergency Watershed Protection Program are two
programs initiated by the Natural Resources Conservation Service, U.S. Department of Agriculture.
The former program seeks to conserve vanishing native plants by identifying resource areas and
developing partnerships with the Coastal Plain Conservancy, USGS National Wetlands Research
Center, Barataria Terrebonne National Estuary Program, and state universities (USDA Natural
Resources Conservation Service 2008), while the later program removes debris from waterways and
downed timber on forest lands (USDA Natural Resources Conservation Service 2009).
Black Bear Conservation Coalition
The Black Bear Conservation Coalition (BBCC) is a group of Federal, State, and private partners in
Mississippi, Louisiana, Arkansas, and east Texas dedicated to restoring the federally listed Louisiana
black bear to suitable habitat. The recovery of this species in Louisiana will be accomplished when:
there are at least two viable subpopulations (one in the Tensas River Basin and one in the Atchafalaya
River Basin); immigration and emigration corridors are established between those two subpopulations;
and, habitat and interconnecting corridors that support those two subpopulations are protected.
Landscape Conservation Cooperatives
To ensure that the Service is “putting science in the right places,” the Directorate determined in April
2009 that the agency needed a national geographic framework for implementing landscape
conservation. Just as migratory bird flyways have provided an effective spatial frame of reference to
build capacity and partnerships for international, national, state, and local waterfowl conservation, this
geographic framework will provide a continental platform upon which the Service can work with
partners to connect site-specific efforts to larger biological goals and outcomes. In its meeting on
August 4-6, 2009, the Directorate approved a map of the geographic framework developed by a team
of Service and U.S. Geological Survey experts from across the country. The map defines
Geographic Areas that provide a spatial frame of reference for building and targeting science capacity
that will support the Service and partners in planning and designing conservation strategies at
landscape scales. It also allows us to more precisely explain to partners, Congress, and the
American public why, where, and how we target conservation resources and how our science-based
efforts connect to a greater whole. Atchafalaya NWR is part of the Gulf Coastal Plains and Ozarks
Landscape Conservation Cooperative (Figure 5).
20 Atchafalaya National Wildlife Refuge
ECOLOGICAL THREATS AND PROBLEMS
In order to prepare a CCP that will establish goals and objectives on refuge management over the
next 15 years, a number of planning steps are followed. One of those steps is a review of known
ecological threats and problems that may hinder the ability of refuge personnel to fulfill the objectives
of the individual refuges. This iterative, ongoing review process has recognized a number of common
regional concerns, which are of particular importance to Atchafalaya NWR.
ATCHAFALAYA BASIN
From a regional perspective, the Atchafalaya Basin faces several, broad ecological threats:
 Logging of the cypress that remains and the bottomland hardwoods continues.
 Lack of public access through private holdings restricts public use and support for
conservation.
 Dredging has changed natural hydraulics, accelerated siltation, and created oxygen-deprived
dead zones where aquatic life cannot survive.
 Increased siltation has created dry land from wetland, and development pressures south of I-
10 are increasing.
 At least one lake in the basin is polluted with mercury, and a fish advisory has been issued.
These regional ecological threats lead to the following specific concerns and threats to the
Atchafalaya NWR.
FOREST LOSS AND FRAGMENTATION EFFECTS ON BIOLOGICAL DIVERSITY
The MAV has changed markedly over the last 100 years as civilization spread throughout the area. From
the 1950s to the 1990s, it has been estimated that 20 million acres of bottomland hardwood forested
wetlands were lost. The greatest changes to the landscape have been in the form of land clearing for
agricultural and flood control projects. Although these changes have allowed people to settle and earn a
living in the area, they have had a tremendous effect on biological diversity and integrity, and
environmental health of the MAV. Vast areas of bottomland hardwood forests have been reduced to
forest fragments, ranging in size from very small tracts of limited functional value to a few large areas that
have maintained many of the original functions and values of forested wetlands. This process, which is
known as forest fragmentation, has reduced the size and connectivity of forest habitat patches and
resulted in the disruption of extensive forest habitats into smaller and smaller isolated patches. Severe
forest fragmentation has resulted in a significant decline in biological diversity and integrity. Species
endemic to the MAV that have become extinct, threatened, or endangered include the red wolf, Florida
panther, ivory-billed woodpecker, Bachman’s warbler, and Louisiana black bear.
Breeding bird surveys show continuing declines in species and species population numbers. The
avian species most adversely affected by forest fragmentation include those that are area-sensitive
(i.e., dependent on large continuous blocks of hardwood forest); those that depend on forest interiors;
those that have special habitat requirements, such as mature forests or a particular food source; and
those that require good water quality. More than 70 species of breeding migratory birds are found in
the region. Some of these species, including Swainson’s warbler, prothonotary warbler, swallow-tailed
kites, wood thrush, and cerulean warbler, have declined significantly and need the benefits of
large forested blocks to recover and sustain their existence. Due to forest fragmentation, the brown-headed
cowbird (a seed-eating bird common in agricultural areas) are now closer to the natural
nesting sites of many forest interior nesting birds. The brown-headed cowbird is a nest parasite that
Draft Comprehensive Conservation Plan 21
Figure 5. Landscape conservation cooperatives and Atchafalaya NWR
22 Atchafalaya National Wildlife Refuge
lays eggs in the nests of other birds, rather than building a nest of its own. Nestling cowbirds often
out-compete host species, because the cowbirds are typically larger and more aggressive. This
results in poor reproductive success and declining populations of forest interior-nesting species.
Fragmentation of bottomland hardwood forests has left many of the remaining forested tracts surrounded
by agricultural lands. Intensive agriculture has removed most of the forested corridors along sloughs that
formerly connected the forest patches. The loss of connectivity between the remaining forested areas
hinders the movement of wildlife between tracts, and reduces the functional values of many remaining
smaller forest tracts. The lost connections also result in a loss of gene flow. Restoring the connections to
allow gene flow and reestablishing travel corridors is particularly important for some wide-ranging species,
such as the threatened Louisiana black bear. (National Audubon Society 1999)
ALTERATIONS TO NATURAL HYDROLOGY AND WETLANDS
In addition to the loss of a vast acreage of bottomland hardwood forested wetlands, there have been
significant alterations in the region’s hydrology due to urban development, river channel modification,
flood control levees, reservoirs, and deforestation, as well as degradation of aquatic systems from
excessive sedimentation and contaminants. The natural hydrology of a region is directly responsible for
the connectedness of forested wetlands and indirectly responsible for the complexity and diversity of
habitats through its effects on topography and soils. Natural resource managers recognize the
importance of dynamic hydrology to forested wetlands and waterfowl-habitat relationships (Fredrickson
and Heitmeyer 1988). Large-scale, man-made hydrological alterations have changed the natural spatial
and temporal patterns of flooding throughout the entire MAV. Since 1932, there has been a net accretion
of nearly 2.5 billion cubic meters of sediments in the Atchafalaya Basin floodway, converting much open
water and cypress swamps to bottomland forests (Louisiana Department of Natural Resources 2009).
In addition, these alterations have reduced both the extent and the duration of annual seasonal flooding.
The loss of this annual flooding regime has had a tremendous effect on the forested wetlands and their
associated wetland-dependent species. In view of the hydrologic changes, it is very difficult–if not
impossible–to fully emulate and reconstruct the structure and functions of a natural wetland. Restoration
of wetland functions is especially difficult since wetlands depend on a dynamic interface of hydrologic
regimes to maintain water, vegetation, and animal complexes and processes (Mitsch and Gosselink
1993). (See further discussion of Hydrology in the Physical Resources section of Chapter II.)
NON-POINT SOURCE POLLUTION AND SILTATION OF AQUATIC ECOSYSTEMS
Aquatic systems, including lakes, rivers, sloughs and bayous, have been degraded as a result of
deforestation and hydrologic alteration. Clearing of bottomland hardwood forests has led to an
accelerated accumulation of sediments and contaminants in all aquatic systems. Many water bodies
are now filled with sediments, which greatly reduce their surface area and depth. Spoil banks, oilfield
canals, and natural levees inhibit the historical sheeting pattern of water flow, causing hypoxic
conditions and poor water quality in many large swamps. Concurrently, the non-point source runoff
of excess nutrients and contaminants is threatening the area’s remaining aquatic resources. In
Louisiana, the Service lists one fish species as threatened (Gulf sturgeon) and one as endangered
(pallid sturgeon). Hydrologic alterations have basically eliminated the geomorphological processes
that created oxbow lakes, sloughs, and river meander scars. Consequently, the protection,
conservation, and restoration of these aquatic resources take on an added importance in light of the
alterations associated with flood control and navigation. From a fishery resource perspective,
excessive sedimentation and poor water quality pose the greatest threats to the Atchafalaya Basin
floodway's aquatic productivity.
Draft Comprehensive Conservation Plan 23
PROLIFERATION OF INVASIVE AQUATIC PLANTS
Compounding the problems faced by aquatic systems is the growing threat from invasive aquatic
vegetation. Static water levels caused by the lack of annual flooding and reduced water depths resulting
from excessive sedimentation have created conditions favorable for the establishment and proliferation of
several species of invasive aquatic plants. Additionally, the introduction of exotic (non-native) vegetation
capable of aggressive growth is further threatening viability of aquatic systems. These invasive aquatic
species threaten the natural aquatic vegetation important to aquatic systems, and choke waterways to a
degree that often prevents recreational use. Massive growth of hydrilla and water hyacinth restricts
access to many areas and exacerbates hypoxic conditions in the swamps.
OIL AND GAS CONTAMINANT ACTIVITIES
Litigation and cleanup activities related to past and present oil and gas extraction activities on refuge
property are needed to mitigate and rehabilitate contaminated well sites. Numerous oil and brine
spills are documented on the refuge, which have damaged natural habitats. A study of Atchafalaya
NWR found that levels of oil contamination near oil and gas facilities are lethal to most species of
wildlife (Shea et al. 2001). Oil and gas companies are often slow, reluctant, and uncooperative in
assuming responsibility and cleaning up these sites – sites which were contaminated by their
extraction activities. As oil and gas exploration and development occurs, it is important that the best
available environmental and petroleum industry standards, information, and technologies are used to
minimize potential impacts to refuge resources and to ensure appropriate compensation and
replacement of lost resources and loss use and access to the public (Strader and Chouinard 2008).
PHYSICAL RESOURCES
CLIMATE
The refuge has a humid, subtropical climate, which is primarily influenced by the refuge's subtropical
latitude and proximity to the Gulf of Mexico. The climate is controlled by two principal air masses:
warm, moist air from the Gulf of Mexico (dominant in the summer); and, cooler, drier air from the
Central Plains (dominant during the winter). Occasional outbreaks of cold continental air in winter
can cause an abrupt and rather large drop in temperature, but cold spells seldom last more than a
couple of days. Extended hot, sultry summers and moderately cool winters are the norm. Normal
average temperatures are about 80oF in summer (June-July-August) and about 50oF in the winter
(December-January-February) (Table 1 and Figure 5). At the weather station in Baton Rouge, all
time maximum and minimum recorded temperatures were 105oF in August 2000 and 8oF in
December 1989, respectively. The growing season is roughly 220 days in length.
Precipitation is abundant and is distributed fairly uniformly throughout the year. Normal annual
precipitation is about 63 inches, with January usually having the greatest amounts of precipitation (~6.20
inches) and October the least (~3.81 inches) (Table 1). Over a span of almost 70 years, total annual
rainfall has varied from 36 to nearly 100 inches. The number of days with measurable precipitation
averages about 113 per year, with precipitation occurring most frequently during summer thunderstorms.
Heavy local storms that produce totals of five or more inches in 24 hours occur about once in 5 years.
Louisiana is impacted by tropical weather disturbances, with an average frequency of one tropical storm
every 1.6 years, one hurricane every 3.3 years, and a major hurricane every 14 years. Tropical storms
and hurricanes are likely to affect the refuge in about three years in ten. The highest recorded rainfall in
the area (Baton Rouge weather station) was observed in April of 1967, with 12.08 inches falling in a 24
hour period. Snowfall does occur rarely, but is generally light and remains on the ground only briefly.
Snowfall accumulation averages only about 0.2 inches a year; but on occasion heavier accumulations
24 Atchafalaya National Wildlife Refuge
have been observed – for example, 3.2 inches of snowfall was recorded in Baton Rouge in February
1988. Prevailing winds, which are usually from the south-southeast, are highest in the spring and
average about seven and a half miles per hour for the year. (NOAA Southern Regional Climate Center
[Accessed 2009]; Spicer et al. 1977; Murphy et al. 1977; and Roth 1998)
CLIMATE CHANGE AND GLOBAL WARMING
The Intergovernmental Panel on Climate Change (IPCC) has concluded that "warming of the climate
system is unequivocal." Global climate change poses risks not only to human health but also to
terrestrial and aquatic ecosystems. Abundance and distribution of wildlife and fish will change,
particularly affecting those species already "at risk." Important economic resources such as agriculture,
forestry, and water resources also can be affected. Warmer temperatures, more severe droughts and
floods, and sea level rise will have a wide range of impacts. All these stresses, added to existing
stresses on resources caused by other influences such as population growth, land-use changes, and
pollution, pose a significant challenge for fish and wildlife conservation.
According to National Oceanic and Atmospheric Administration (NOAA) and National Aeronautics
and Space Administration (NASA) data, the Earth's average surface temperature has increased by
about 1.2 to 1.4ºF since 1900. The ten warmest years in the 20th century have all occurred within the
past 15 years. Some climate models, based on emissions of greenhouse gases, primarily carbon
dioxide, methane, and nitrous oxide, predict that average surface temperatures could increase from
2.5 to 10.4oF by the end of this century. The frequency of extremely hot summer days is expected to
increase, along with this general warming trend. Increases in atmospheric CO2 are attributed largely
to human activities, which have grown rapidly since the 1940s. The burning of fossil fuels adds 5.6
billion tons of carbon (deforestation contributes another 0.4 to 2.5 billion tons of carbon) to the
atmosphere each year.
Global warming, resulting in melting of glaciers and ice sheets and the thermal expansion of ocean
water, will cause sea levels to rise. Globally, sea level has risen 4–10 inches during the past century.
NASA estimates that yearly, 50 billion tons of ice is melting from the Greenland ice sheet. NASA
aerial surveys show that more than 11 cubic miles of ice are disappearing from the ice sheet
annually. Considering that land less than 10 meters above sea level contains 2 percent of the world's
land surface but 10 percent of its population, major impacts will be felt by large numbers of people
living on the lower-lying coastlands, particularly the Gulf Coast states. In Louisiana, coastal land
subsidence exacerbates the effects of sea level rise. At Grand Isle, sea level already is rising by 41
inches per century, and is likely to rise another 55 inches by 2100. A 1- to 3-foot increase in sea level
over the next century would submerge about 70 percent of Louisiana's remaining salt marshes, as
well as convert inland freshwater marshes to brackish or salt marshes. Louisiana currently is losing
coastal wetlands at a more rapid rate (~25 to 50 square miles a year) than any other coastal state or
region in the United States (EPA 1997). The IPCC lists New Orleans as North America's most
vulnerable city to the impacts of climate change.
In addition to the rising seas, the effects of climate change and global warming will be changes in
weather/rainfall patterns, decreases in snow and ice cover, rising sea levels, and stressed ecosystems.
For the southeastern United States and the Louisiana region, this could mean extreme precipitation
events; greater likelihood of warmer/dryer summers and wetter/reduced winter cold; and, alterations of
ecosystems and habitats due to these changes in weather patterns. For Atchafalaya NWR, warmer
conditions would favor increased densities of vegetation and wetter conditions would favor trees that are
better adapted to these conditions, such as bald cypress and water tupelo. If conditions become drier, the
current range and density of forests would be reduced and replaced by grasslands and pasture and the
probability of wildfires would increase.
Draft Comprehensive Conservation Plan 25
A recent study of the effects of climate change on eastern United States’ bird species concluded that
as many as 78 bird species could decrease by at least 25 percent while as many as 33 species could
increase in abundance by at least 25 percent due to climate and habitat changes (Matthews et al.
2004). In short, global warming could increase storm intensity, negatively change Atchafalaya NWR's
ecologically important plant species, alter the spread of invasive species, increase drought-induced
fires, transition sub-tidal marshes and shift marshes inland, and further imperil already threatened and
endangered species.
With respect to future impacts on other Service refuges, the IPCC projects with "high" or "very high
confidence" the following likely events (Eisenhauer 2007):
 "Coasts are projected to be exposed to increasing risks, including coastal erosion, due to climate
change and sea-level rise and the effect will be exacerbated by increasing human-induced
pressures on coastal areas."
 Coastal wetlands are projected to be negatively affected by sea-level rise.
 "Many millions more people are projected to be flooded every year due to sea-level rise by the
2080s."
 Warming in North America's western mountains is projected to cause "decreased snow pack,
more winter flooding, and reduced summer flows, exacerbating competition for over-allocated
water resources."
 "Disturbances from pests, diseases, and fires are projected to have increasing impacts on forests,
with an extended period of high fire risk and large increases in area burned."
 Heat waves will increase during the course of the century in North America, and the "growing
number of the elderly population is most at risk."
 In North America, readiness for increased exposure to climate change impacts in coastal
communities is low.
 Small islands, whether in high latitudes or the tropics have characteristics which make them
especially vulnerable to the effects of climate change, sea level rise and extreme events.
 Heavy precipitation events are very likely to increase in frequency.
 Drought-affected areas will likely increase in extent.
 "The resilience of many ecosystems is likely to be exceeded this century by an unprecedented
combination of climate change, associated disturbances (e.g., flooding, drought, wildfire, insects,
and ocean acidification) and other global climate change drivers."
 "For increases in global average temperature exceeding 1.5-2.5 °C … there are projected to be
major changes in ecosystem structure and function, species' ecological interactions, and species'
geographic ranges, with predominantly negative consequences for biodiversity, and ecosystem
goods and services, e.g., water and food supply."
 "Regional changes in the distribution and production of particular fish species are expected due to
continued warming, with adverse effects projected for aquaculture and fisheries."
 Poor communities are especially vulnerable.
 Projected climate change is likely to affect the health status of millions of people through:
increases in malnutrition; increased deaths, disease, and injury due to heat waves, floods, storms,
fires and droughts; and altered distribution of some infectious disease vectors. The negative
health impacts outweigh any positive impacts.
 In Polar Regions, it is projected that there will be reductions in thickness and extent of glaciers
and ice sheets, "and changes in natural ecosystems with detrimental effects on many organisms
including migratory birds, mammals and higher predators."
 There will be detrimental impacts on infrastructure and traditional indigenous ways of life, and
there is "medium confidence" that there will be reduced heating costs and more navigable
northern sea routes. (U.S. Environmental Protection Agency [EPA] 2009a and Krabill et al. 2000)
26 Atchafalaya National Wildlife Refuge
However, it should be noted that humans, plants, and animals, have coexisted on this planet and
have evolved together for many thousands of years. They have adapted to ice ages as well as
warming trends, and some species have managed to avoid extinction. The above discussion on
climate change is not intended to promote fear but only awareness that climate change is natural and
inevitable, and humans may be increasing the rate of change with our actions.
Table 1. Climatological normals for the years 1971-2000 - Baton Rouge, LA
(Ryan Air Port Weather Station)
Month
N O R M A L
Mean
(°F)
Minimum
(°F)
Maximum
(°F)
Rainfall
(inches)
Snowfall
(inches)
Jan 50.1 40.2 60.0 6.19 0.0
Feb 53.5 43.1 63.9 5.10 0.2
Mar 60.3 49.6 71.0 5.07 0.0
Apr 66.6 55.8 77.3 5.56 0.0
May 74.0 64.1 84.0 5.34 0.0
Jun 79.7 70.2 89.2 5.33 0.0
Jul 81.7 72.7 90.7 5.96 0.0
Aug 81.4 71.9 90.9 5.86 0.0
Sep 77.5 67.5 87.4 4.84 0.0
Oct 68.1 56.4 79.7 3.81 0.0
Nov 59.0 47.9 70.1 4.76 0.0
Dec 52.4 42.1 62.8 5.26 0.0
Annual 67.0 56.8 77.3 63.08 0.2
Source: (NOAA, accessed May 2009)
Draft Comprehensive Conservation Plan 27
GEOLOGY AND TOPOGRAPHY
Bedrock in the area of Atchafalaya NWR consists of Tertiary and Cretaceous sands formed as beach
deposits during the retreat of the Cretaceous ocean from the midsection of the U.S. Alluvial deposits
from flooding and lateral migration of the Mississippi River typically lie above the bedrock. These
sediments are sandy to clayey fluvial deposits of Quaternary age and are many meters thick. The
surface of Louisiana is characterized by geologically young sedimentary sequences that were
deposited in or adjacent to rivers and deltas in a coastal-plain setting. These deposits indicate that a
major river system corresponding to the Mississippi has persisted at least since the Gulf of Mexico
began to form. Through time, fluvial, deltaic, and coastal deposits have advanced southward toward
the coastline and continue to fill the Gulf of Mexico. Most of Louisiana was formed by these Mississippi
River sediment deposits. As sea-level rose and fell over this low-lying region, the Mississippi River
carried vast sediment loads and sedimentary rocks from the core of the North American continent and
deposited it on the rim of the Gulf of Mexico. Organic matter from highly productive marine waters was
deeply buried under the sediments, and through various processes has turned into petroleum. Massive
salt deposits, formed by evaporation of sea water during pre-historic dry periods, provide a stable
confining layer for the underlying petroleum. Most surface exposures consist of Quaternary
(Pleistocene and Holocene) sediment (Figure 6) (Louisiana Geological Survey 2008; Louisiana
Department of Environmental Quality et al. 2007a; USFWS 2006a; and Boykin 1990).
Tertiary
About 25 percent of Louisiana's surface is comprised of rocks of Tertiary age. The oldest surface
rocks are the Paleocene/Eocene formations (Wilcox Group) found in the Sabine Uplift of
northwest Louisiana, which date back over 54 million years and are composed of a thick series of
non-marine sands, silty sands, clays, and gravels with some thick deposits of lignite. North
central Louisiana is typified by Eocene formations (Claiborne and Jackson Groups from 54 to 38
million years ago, mya) of non-marine and marine medium to very fine grained sands, silts, and
silty clays, which lie on top of elevated salt-domes. Oligocene (38 to 26 mya) and Miocene (26 to
5 mya) formations (Catahoula and Fleming) are apparent, but not dominant, in central Louisiana
and are typified by tan to reddish brown silt with some clay and minor amounts of very fine sand.
Quaternary-Pleistocene
Approximately 20-25 percent of the state's surface is occupied by deposits associated with
Pleistocene (1.6 to 0.01 mya) Terraces in the eastern and western parts of southern Louisiana.
These terraces also consist of sand, gravel, and mud, but underlie raised, flat surfaces with varying
degrees of tilt and dissection depending on their relative ages. These surfaces are remnants of pre-existing
floodplains, and form trends along the major rivers in north Louisiana and coast-parallel belts
in south Louisiana.
Quaternary-Holocene
Holocene (10,000 years to present) alluvial sediments of the Mississippi, Red, Atchafalaya, and other
rivers and smaller tributaries, together with coastal marsh deposits, occupy about 55 percent of
Louisiana’s surface. The alluvial sediments consist of sandy and gravelly channel deposits mantled
by sandy to muddy natural levee deposits, with organic-rich muddy backswamp deposits in between;
coastal marsh deposits are chiefly fine grained clay, silt, and organic matter. The coastal region of
Louisiana was formed over the last 7,500 years.
28 Atchafalaya National Wildlife Refuge
Figure 6. Generalized geologic map of Louisiana
Draft Comprehensive Conservation Plan 29
Atchafalaya NWR is underlain by these Holocene alluvial sediments from the Mississippi, Red,
and Atchafalaya Rivers. Bayous and sloughs are common throughout the refuge. The
topography of the refuge has been greatly influenced by the build-up of the land surfaces and
streambeds through the natural deposition of the Holocene alluvial materials. The resulting relict
channels and natural levees are often referred to as ridge and swale topography (wide flats
broken by low ridges and swales are typical). Human disturbances, including construction of
artificial levees and channelization projects, have altered these natural alluvial processes within
the Mississippi and Atchafalaya River floodplains. Elevations range from about 13 feet above
mean sea level (msl) to 23 feet msl on Atchafalaya NWR. Local relief within the floodplains is
less than 3 feet. Although the floodplain would appear flat to casual observance, the 2 to 3 feet
of local relief has a dramatic impact on vegetation changes. This is due to a shallow water table
and changes in internal drainage caused by localized sedimentation patterns.
SOILS
Soils directly influence the kind and amount of vegetation and the amount of water available. In this
way they indirectly influence the kind of wildlife that can live in an area. Soils are organized into a
taxonomic classification system by the U.S. Department of Agriculture, Natural Resources
Conservation Service, in which each soil is categorized by order, suborder, great group, subgroup,
family, and soil series. Nationwide, there are twelve soil orders, of which three soil orders are
predominantly found in the Atchafalaya NWR area: Vertisols (great group Epiaquerts), Entisols (great
group Hydraquents), and Inceptisols (great group Endoaquepts). Within these three orders, there are
three dominant soil series found on Atchafalaya NWR:
 The Convent soil series (classified as thermic Fluvaquentic Endoaquepts) consists of very
deep, somewhat poorly drained, low to negligible runoff, moderately permeable soils that
formed in recent loamy alluvium. The soils are found on nearly level to very gently sloping
natural levee positions on flood plains, with slopes ranging from 0 to 3 percent. Most areas
are protected from flooding by levees. Convent soils are neutral to mildly alkaline silty loams.
They are high in fertility. Plant roots penetrate easily, and water and air move moderately fast
through the soil. Convent soils are found on the highest elevations of the refuge, generally
along streams, and on the natural levees of Alabama Bayou, Bayou Des Glaises, Whiskey
Bayou Pilot Channel, and other streams. These soils occur in several large tracts ranging
from about 300 to over 2,000 acres in size. The native forest vegetation found on this soil
series is predominantly oaks, cottonwoods, hickories, and sweetgum. Areas that have been
cleared are primarily used for cotton, sugarcane, small grain, soybeans, and corn.
 The Fausse soil series (classified as hyperthermic Vertic Endoaquepts) consists of very
deep, very poorly drained, low runoff, very slowly permeable soils that formed in thick
deposits of clayey alluvium. Typically the surface layer of the Fausse soils is slightly acid.
The clayey soil restricts root penetration. These soils are flooded much of the time and are
found in low, ponded backswamp areas with slopes of less than 1 percent. Fausse soils are
saturated throughout during normal years, and saturated below a depth of 2 feet even during
dry years. These soils occur in large tracts ranging from several hundred acres to several
thousand acres in size. These soils are mainly used for wildlife habitat and for growing
timber, but their potential for timber production is poor and timber management is difficult due
to flooding and wetness. Timber is dominantly bald cypress, water tupelo, and red maple.
30 Atchafalaya National Wildlife Refuge
 The Sharkey soil series (classified as thermic Chromic Epiaquerts) are similar to Fausse
soils. They also consist of very deep, poorly and very poorly drained, very slowly permeable
soils that formed in clayey alluvium. Sharkey soils are distinguished in that they are formed in
clayey alluvium that is dominantly smectites (phyllosilicate minerals). Typically, the surface
layer of the Sharkey soils is slightly acid, increasing in alkalinity with depth. These soils are
found on the flood plains and low terraces of the Atchafalaya River with slopes usually less
than 1 percent, but sometimes up to 5 percent. They may also be found in backswamps and
abandoned channels and on interfluves and low terraces. These soils occur in tracts as small
as 50 acres, with other tracts that range in size from several hundred to over 1,000 acres.
These soils provide good natural habitat and their potential for woodland is good. Frequently
flooded and ponded areas are mainly bottomland hardwoods – common trees might be black
willow, persimmon, red maple, and various oaks. When cleared, the Sharkey soils are used
mostly for cropland, soybeans, and rice being the principal crops (Murphy et al. 1977; Spicer
et al. 1977; USDA NRCS 1998, 2002, and 2004; and Boykin 1990).
HYDROLOGY AND WATER QUALITY
Groundwater Hydrology
Louisiana's ground water supply is contained within geologic formations termed aquifers. Aquifers
are permeable, saturated zones of rock, sand, and gravel confined by layers of clay and silt that
contain sufficient water to yield usable amounts to wells. The aquifers that supply fresh ground water
to most of Louisiana are contained within Quaternary or Tertiary sediments of sand and gravel
deposited in the Gulf Coast geosyncline and the Mississippi embayment (Chapter II, Geology and
Topography). Louisiana has an abundance of fresh ground water within these sand and gravel
deposits, but these aquifers and confining layers are not uniformly distributed, and the quality of the
ground water varies from one aquifer to another. Louisiana's abundant ground water supply is held in
13 major aquifers and aquifer systems (Table 2). Typically groundwater in Louisiana moves in a
southerly direction, and towards stream/river valleys; however, pumping in urbanized and
industrialized areas has resulted in the formation of cones of water table depression, thus altering
regional ground water flow patterns in major urban and industrial areas (viz. Baton Rouge). The four
largest producing aquifer systems in Louisiana are: the Southern Hills aquifer system in the
southeast (comprised of the Chicot equivalent, Evangeline equivalent, and Jasper equivalent aquifer
systems); the Chicot aquifer system in the southwest; the Sparta aquifer in the northwest, and
Mississippi River Alluvial aquifer running from the northeast, south through the central part of
southern Louisiana.
Atchafalaya NWR is underlain by the Mississippi River Alluvial aquifer. The Mississippi River
alluvium consists of fining upward sequences of gravel, sand, silt, and clay of Holocene-Pleistocene
age. The aquifer is poorly to moderately well-sorted, with fine-grained to medium-grained sand near
the top, grading to coarse sand and gravel in the lower portions. It is confined by layers of silt and
clay of varying thicknesses and extent. The Mississippi River Alluvial aquifer is hydraulically
connected with the Mississippi River and its major streams. Recharge of the Mississippi River
Alluvial aquifer is accomplished by direct infiltration of rainfall in the river valley, lateral and upward
movement of water from adjacent and underlying aquifers, and overbank stream flooding (water
moves into the aquifer when stream stages are above aquifer water levels). The amount of recharge
from rainfall depends on the thickness and permeability of the silt and clay layers overlying the
aquifer. Water levels fluctuate seasonally in response to precipitation trends and river stages. Water
levels are generally within 30 to 40 feet of the land surface and movement is down gradient (in a
generally southerly direction) and toward larger rivers and streams. On Atchafalaya NWR, ground
water is seldom far from the surface with many old wells on the refuge only 15-30 feet deep. Natural
Draft Comprehensive Conservation Plan 31
aquifer discharge occurs by seepage of water into the Mississippi River and its tributaries. The
hydraulic conductivity of the aquifer varies between 10-530 feet/day, and the maximum depths of
occurrence of freshwater range from 20 feet below sea level, to 500 feet below sea level. Typical
wells yield from less than 500 to as much as 4,000 gallons per minute (Louisiana Department of
Environmental Quality 1996).
Groundwater Quality
The water of the Mississippi River Alluvial aquifer is very hard and has high iron content.
Consequently, the aquifer is not well-suited for drinking water use. However, the aquifer is widely
used for irrigation (e.g., rice, soybeans, corn) and aquaculture (e.g., catfish). Over 400 million gallons
of freshwater are withdrawn from the Mississippi River Alluvial Aquifer each day, of which over 70
percent is used for agricultural irrigation (Sargent 2007). Water quality data collected over the period
FY96 to FY05 by the Louisiana Department of Environmental Quality (LDEQ) from wells in the
Mississippi River Alluvial aquifer show that the aquifer is of poor quality when considering taste, odor,
or appearance (Table 3). Over this sampling period (FY96 to FY05) the aquifer was found to be
increasing in color, sulfate, barium, and iron concentrations; while chloride concentrations were
decreasing. Additionally, several wells showed concentrations of arsenic above the present 10 ppb
maximum contaminant level (MCL). Ground water quality data collected in FY05 are listed in Table 3
(Louisiana Department of Environmental Quality 2005)
Surface Water Hydrology -- Atchafalaya Basin Floodway System (ABFS)
The Atchafalaya River Basin, located in south-central Louisiana, is a natural alluvial flood plain of the
Atchafalaya River which heads at Old River near Simmesport, Louisiana and flows into the Gulf of
Mexico, about 140 miles to the south. The Atchafalaya River is the largest distributary of the
Mississippi River. The Atchafalaya River Basin has been described as the greatest river swamp in
the United States, and it encompasses more than one-half million acres of wetlands, providing habitat
for a diversity of wildlife species. Its waters also support a tremendous sport and commercial
fisheries resource.
Alteration of the natural drainage pattern began in the late 1880s, with closures or partial closures of
various tributaries and distributaries along the Atchafalaya River for navigation purposes. Those
closures were not substantial and were overtopped and/or washed out during flood events. Railroad
construction across the Atchafalaya Basin Floodway (east-west) in the early 1900s was one of the
earliest activities that permanently affected water flow in the Atchafalaya Basin. By 1910, private and
federal flood control levees along the Atchafalaya River were constructed as far south as Alabama
Bayou; however, these levees were undersized and easily overtopped by seasonal floods. Following
the flood of 1927, in order to provide for safe passage of major floods in the lower Mississippi system
below Old River, the USACE modified a portion of the natural Atchafalaya Basin to convey flood
water in excess of the capacity of the levied Mississippi and Red rivers. The USACE began building
Atchafalaya Basin Floodway levees, closing distributaries and tributaries of the Atchafalaya River,
and dredging the Atchafalaya River and using the dredged material to build levees confining the river
flows. This Atchafalaya Basin Floodway was formed by constructing protection levees to the east,
west, and parallel to the Atchafalaya River channel. In addition to the Atchafalaya River, the
Morganza Floodway (on the east) and the West Atchafalaya Floodway (on the west), divert excess
flood waters of the levied river channels into the Atchafalaya Basin. Today, these three floodways,
Atchafalaya, Morganza and West Atchafalaya, are collectively referred to as the Atchafalaya Basin
Floodway System (ABFS). (Strader and Chouinard 2008)
32 Atchafalaya National Wildlife Refuge
The ABFS is 65 miles long, 15 miles wide, and lies on both sides of the Atchafalaya River from
Krotz Springs, Louisiana, to Morgan City, Louisiana. Flow is terminally discharged into
Atchafalaya Bay and the Gulf of Mexico through the lower Atchafalaya River at Morgan City and
through an artificial channel (known as the Wax Lake Outlet) about 10 miles west of Morgan City.
The USACE operates and maintains the ABFS, which is designed to divert approximately 1.5
million cubic feet per second (cfs) of water from the Mississippi River's (and Red River's)
combined flow of about 3 million cfs during flood conditions. To accomplish this, the ABFS
independently diverts water from the Mississippi and Red Rivers into the Morganza Floodway
(~600,000 cfs), the Atchafalaya River (~650,000 cfs), and the West Atchafalaya Floodway
(~250,000 cfs).
The east Atchafalaya Basin protection levees were constructed in the late 1930s using adjacent borrow
material which created channels next to those levees. More substantial distributary channel closures
were constructed in the early 1930s and by 1955 Alabama Bayou, Bayou Des Ourses, and Bayou Des
Glaises were permanently closed. In 1956, the USACE completed the navigation channel through the
Atchafalaya Basin, which included the Whiskey Bay Pilot Channel. Dredged material from that channel
was disposed on the adjacent banks effectively constructing a levee that confined river flows. Further
modifications to the area during the late 1950s to the late 1960s included the construction of oil and gas
exploration canals and roads. The Interstate 10 (I-10) Canal was dug between 1970 and 1971. After
completion of this particular canal, three weirs constructed of concrete debris and having a sill elevation of
approximately 5 feet were placed in the canals that would drain the I-10 Canal. Those weirs prevent the
dewatering of the area north of I-10, including the Atchafalaya NWR, during low-water periods.
On a daily basis, water from the Mississippi River is diverted down the Atchafalaya River through the Old
River Control Complex. The Old River Control Complex consists of several structures that divert water
from the Mississippi River while preventing the Mississippi River from changing its course to that of the
Atchafalaya River. The volume of water diverted by the Old River Control Complex is equal to about 30
percent of the combined flow of the Red River and the Mississippi River. Average annual flow of the
Atchafalaya River is 229,000 cfs (USACE 1977-2001) (U.S. Geological Survey 2001).
Current flood control features along the main channel of the Atchafalaya River consist of Atchafalaya
River levees, distributary channel closures (both natural and manmade), and channel realignments.
The east Atchafalaya River levee confines flows to the river during all but the highest river stages,
eliminating and/or reducing the extent of headwater aquatic habitats previously available during lower
river stages. Distributary channel closures (e.g., Bayou DesGlaises, Alabama Bayou) eliminated all
river flows, excluding extremely large floods. In addition, dredging and confining of most floods to
within the river banks has increased the efficiency of the river’s channel. A more efficient channel
reduces the extent and duration of overbank flooding. This efficiency also allows water within the
major dredged channels (i.e., Atchafalaya River) to maintain a higher water surface elevation (i.e.,
hydraulic head) than water slowly flowing through the adjacent swamps. Because the higher water
surface elevation effectively prevents any connecting channels from functioning as outlets, the areal
extent of backwater flooding in the adjacent swamps has increased. Flooding in those backwater
swamps may form areas of stagnant water that are usually characterized by poor water quality
(primarily low dissolved oxygen levels). The higher water surface elevation in the more efficient
channels also allows sediment-laden river water to flow north through distributaries that historically
were outlets. Waters flowing north into those distributaries result in shoaling within the channel and a
corresponding reduction in the channel’s cross-section. The reduced cross-section decreases water
flowing through the channel, thus reducing headwater habitat. In addition, sedimentation occurs in
open water areas and swamps directly connected to those major channels reducing the areal extent
of their aquatic habitats.
Draft Comprehensive Conservation Plan 33
Drainage is in a north to south direction with runoff from the refuge being gathered by many small
bayous which flow primarily into Alabama Bayou, Little Alabama Bayou, and Bayou Des Glaises. The
three bayous intersect with Alabama Bayou being the primary drainage from the refuge to the
Atchafalaya River. Before construction of the Atchafalaya Basin Floodway, water from the
Atchafalaya River flowed through the area primarily from Alabama Bayou into Big and Little Alabama
Bayous and Bayou DesGlaises and then into the East Fork of Bayou DesGlaises. From the East
Fork of Bayou DesGlaises water would flow via over bank or through swamps and many smaller
bayous and leave the present location of the Atchafalaya NWR. Today, water levels in Atchafalaya
NWR fluctuate from almost complete inundation during periods of high rainfall and when the ABFS is
being used as a relief outlet, to only the three primary bayous (Alabama, Little Alabama, and Bayou
DesGlaises) containing surface during droughts. Late winter and spring usually experiences some
flooding of the refuge with late summer and fall being the driest periods.
Surface Water Quality
Water quality data from the area was collected from 1974 to 1977 by the Environmental Protection
Agency (Hern et al. 1980) and recently by the Service. Using four parts per million (ppm) dissolved
oxygen (DO) level as a criteria to identify decreased water quality, Hern et al. (1980) found that most
of the low DO levels occurred in the spring, followed next by summer, fall, and then winter. With two
ppm DO level criteria the same trend was noticed. Stagnant water conditions occur during high water
stages when backwater flooding, minimal water circulation, and high water temperatures (i.e., >18oC)
predominate. These conditions lead to low dissolved oxygen levels, which are primarily the result of
decomposition of organic material, high water temperatures, and insufficient supply of oxygenated
river water (Constant et al. 1999, Hern et al. 1980, Wells and Demas 1977). Limited Service water
quality samples indicated a large variation in DO levels within and between years. In addition,
stratification of the water column often occurred with bottom DO levels often below the two ppm level.
In a summary of the DO conditions in Hern et al. (1980) stated, “. . . most of the extremely low DO
conditions during high water conditions were at locations with little or no water circulation due to man-made
or natural obstructions.”
Lakes and bayous that become isolated during low river stages may also experience high
temperatures as well as low dissolved oxygen levels. However, as the turbidity from high river stages
decreases, a corresponding increase in aquatic plant growth sometimes occurs. Those aquatic
plants help to maintain a dissolved oxygen level that will support aquatic life. In other aquatic
habitats, plankton may produce enough dissolved oxygen to support aquatic life throughout most of
the water column.
Constant et al. (2002) examined the interactive effects of water hyacinth and/or hydrilla species
(introduced exotic floating plants) coverage, primary production, river water inputs, and dissolved
oxygen. They found that decreased dissolved oxygen concentrations in areas isolated from river flow
was spatially and temporally variable due to: the proximity to river water; the obstruction of sunlight at
the surface of the water; and, the potential for biological respiration to consume dissolved oxygen.
The capacity of isolated areas to replenish dissolved oxygen through photosynthesis was contrasted
in 1998 (no hyacinth cover), with the capacity of river water to supply oxygen to the same sites in the
absence of photosynthesis in 1997 (complete hyacinth cover). Isolated areas were able to produce
more oxygen than was consumed in respiration when hyacinth cover was absent in 1998. However,
when hyacinth covered the surface in 1997, oxygen saturation continually decreased with distance
from the river water inflow sites, demonstrating the limited distance over which the river could supply
oxygenated water to the floodplain. Because of the altered hydrology, primary production must
supply floodplain organisms with oxygen, and extensive floating aquatic vegetation cover minimizes
photosynthesis (i.e., primary production) and the associated oxygen production.
34 Atchafalaya National Wildlife Refuge
An extensive fish kill occurred in 1992 and 2008 when Hurricanes Andrew and Gustav passed over the
Atchafalaya Basin Floodway. The fish kill is believed to be a result of anoxic conditions produced by
the suspension of anaerobic sediments and the decomposition of large amounts of organic debris (e.g.,
leaves, branches) in the water bodies. Anoxic conditions persisted over much of the lower Atchafalaya
Basin Floodway for almost one month. A few localized areas remained anoxic for almost two and one-half
months following the passage of the hurricane (Charles Demas, U.S. Geological Service, pers.
comm.). Approximately 2 years passed before fish populations recovered from hurricane Andrew
(Louisiana Department of Wildlife and Fisheries 1995). It is believed that similar recovery rates would
occur with any subsequent storms.
The Louisiana Department of Environmental Quality (LDEQ) has issued a fish consumption advisory
for fish caught in Big Alabama Bayou. This advisory was in response to elevated mercury levels
found in largemouth bass, crappie, bigmouth buffalo, freshwater drum, flathead catfish, and bowfin
(LDEQ 2003). Sediments sample from on and/or adjacent to the Atchafalaya NWR contained
mercury, however, the concentration did not exceed a probable effects concentration level for benthic
communities (Shea et al. 2001). Mercury found within the area is most likely a product of
atmospheric deposition.
Water quality issues related to agricultural chemicals have also been found in the Atchafalaya Basin.
Shea et al. (2001) examined the chemical contamination on U.S. Fish and Wildlife refuges within the
Lower Mississippi River Ecosystem. Nitrates and atrazine were the major contaminants found in the
Atchafalaya Basin. A total of 17 of 50 pesticides were detected in water samples taken from on
and/or adjacent to Atchafalaya NWR. Atrazine was detected at a level above the aquatic life criteria.
Agricultural activities north of the refuge possibly contribute to the occurrence of those compounds.
Polychlorinated biphenyl’s (PCBs) were detected at elevated levels in sediments but at low enough
concentrations to not cause adverse effects to the benthic community. It was also detected in
predatory and benthic fish but those levels were also low enough to not cause adverse effects.
Polycyclic aromatic hydrocarbons (PAHs) are associated with the production, transport and use of
fossil fuels and were detected near active and/or abandoned oil field production equipment (Strader
and Chouinard 2008).
Draft Comprehensive Conservation Plan 35
Table 2. Louisiana's major aquifers and aquifer systems
Aquifer Location Sediments Recharge Use Description
Cockfield Northeast Louisiana Very fine to fine sand Rainfall on outcrop area; leakage from
overlying alluvial aquifer; leakage from
underlying aquifers
600 million
gal/day; primarily
public supply
Water movement is eastward and southward
Sparta North and north-central
Louisiana
Very fine to medium
sand; interbedded
with thin layers of clay
and lignite
Rainfall on outcrop area and water moving
downward through terrace deposits;
leakage from overlying Cockfield and
underlying Carrizo-Wilcox aquifers
64 million gal/day;
primarily industry
and public supply
Recharge towards east and south and
Monroe; high sodium in eastern part of aquifer
makes unsuitable for irrigation
Carrizo-Wilcox Northwest Lousiana;
both sides of Red
River
Fine to medium sand,
silt, clay, and lignite
Rainfall on surficial sediments 13 million gal/day;
public, domestic,
and small farm
supply
Aquifer discharges into Red and Sabine
Rivers
Chicot Aquifer
System
Southwest Louisiana Coarse sand and
gravel
Primarily in northern part of aquifer; rainfall
in Allen and Beauregard Parishes; leakage
from overlying and underlying areas
690 million
gal/day; primarily
agriculture
Ground water movement towards coast and
pumping stations; water soft in recharge and
southern area; harder in central and
southeastern areas; subdivision: 220 ft. sand,
500 ft. sand, 700 ft. sand, upper sand unit;
lower sand unit
Evangeline Southwest Louisiana Fine to medium sand;
sand units separated
by clay
Rainfall in Vernon, Avoyelles, and Rapides
Parishes; leakage from Chicot aquifer;
leakage from underlying aquifers
14 million gal/day;
primarily public
supply
Water generally moves southward; seepage
into Sabine and Calcasieu Rivers towards
west and into Atchafalaya River towards east;
overlying Chicot system provides water for
irrigation
Jasper Aquifer
System
Southwest Louisiana Fine to medium sand;
extensive clay layers
separate from
overlying and
underlying aquifers
Rainfall in Vernon and Natchitoches
Parishes
46 million gal/day;
primarily public
supply
Comprised of the Williamson Creek (upper)
aquifer and the Carnahan Bayou (lower)
aquifer; ground water movement towards
south and southeast and pumping centers;
water from Carnahan Bayou slightly harder
than from Williamson Creek
Catahoula Western edge of
Louisiana in a
northeasterly direction
across the State
Fine to medium sand;
forms sandstone
Rainfall on outcrop area and percolating
through overlying alluvial and terrace
deposits
3 million gal/day;
primarily public
supply
Limited use as a source of freshwater; divided
into three freshwater areas by saltwater under
Red River Valley and Little River divide.
Chicot
Equivalent
Southeast Louisiana Fine to course sand
and gravel
Along Louisiana-Mississippi state line;
rainfall or leakage from surficial sands;
leakage from underlying aquifers
88 million gal/day;
primarily industry
Principal sands are 400 ft and 600 ft Baton
Rouge, Gramercy, Norco, and Gonzales-New
Orleans; 1,200 ft New Orleans; upper
Pontchatoula; water generally moves
southward, saltwater moves northward across
Baton Rouge fault into 600 ft sand; 1,200 ft
sand in New Orleans not pumped because
water is saline; upper Pontchatoula is least
developed
Evangeline
Equivalent
Southeast Louisiana Fine to medium sand In south-central and southwest Mississippi;
rainfall and surficial sands
68 million gal/day;
primarily public
use
Comprised of 800 ft sand, 1,000 ft sand, 1,200
ft sand, 1,500 ft sand, and 1,700 ft sand of the
Baton Rouge area; lower Pontchatoula; Big
Branch; Kentwood; Abita; Covington; and
Slidell aquifers; water generally moves
southward
Jasper
Equivalent
Southeast Louisiana Fine to course sand In southwestern Mississippi, rainfall on
surficial sands; leakage from overlying
aquifers
112 million
gal/day; primarily
industry and
Principal aquifers are 2,000 ft sand, 2,400 ft
sand, and 2,800 ft sand of Baton Rouge area;
Tchefuncta; Hammond; Amite; and Ramsay
36 Atchafalaya National Wildlife Refuge
Aquifer Location Sediments Recharge Use Description
public use aquifers
Mississippi River
Alluvial
Follows the river’s
course from
northeastern to south-central
Louisiana
Sand and gravel; fine
grained in upper part
grading to course in
lower part; confined
by overlying fine
sand, silt, and clay (0
to 150 ft thick)
Rainfall on aquifer surface and underlying
aquifers; leakage from underlying aquifers;
locally from Mississippi River near
pumping centers
284 million
gal/day; primarily
irrigation
In southern Louisiana joins with alluvium of
the Atchafalaya River to form a large alluvial
aquifer; water generally moves southward;
seepage into major streams and withdrawal
from wells; requires treatment for domestic
and public supply use; saltwater from
underlying aquifers, oil and gas activities, and
ancient unflushed saltwater; threats include
improperly plugged or abandoned wells and
misuse of agricultural chemicals; no detection
of major organic contamination
Red River
Alluvial
Red River Valley Clay, silt, and fine
sand grading to
course sand and
gravel
Rainfall on fine-grained surficial
sediments; leakage from underlying
aquifers
4 million gal/day;
primarily
aquaculture
Small amount of water pumped because
treatment is required for most uses
Upland Terrace Discontinuous band
along northwestern
edge of Red River
Valley and western
edge of Mississippi
River Valley
Clay, silt, and fine
sand grading to
course sand and
gravel
Rainfall on fine-grained surficial
sediments; leakage from underlying
aquifers
22 million gal/day;
primarily public
supply and
industry
Not extensively used for freshwater due to
potential for contamination
Source: (Louisiana Department of Environmental Quality 2007a)
Draft Comprehensive Conservation Plan 37
Table 3. Mississippi River alluvial aquifer water quality data FY2005
PARAMETER MINIMUM MAXIMUM AVERAGE
FIELD
Temperature (°C) 14.75 23.55 19.62
pH (SU) 6.62 7.44 6.98
Specific Conductance (mmhos/cm) 0.03 1.28 0.80
Salinity (ppt) 0.01 0.64 0.40
TDS (g/L) 0.02 0.83 0.52
LABORATORY
Alkalinity (ppm) 2 616 347.16
Chloride (ppm) 8.6 246 48.64
Color (PCU) 5 220 37.98
Specific Conductance (umhos/cm) 10 1356 766.21
Sulfate (ppm) 1.25 186 22.46
TDS (ppm) 178 896 488.96
TSS (ppm) 4 56 16.42
Turbidity (NTU) 1 280 75.25
Ammonia, as N (ppm) 0.1 6.54 1.10
Hardness (ppm) 5 530 297.50
Nitrate-Nitrite, as N (ppm) 0.05 3.08 0.19
TKN (ppm) 0.1 7.86 1.36
Total Phosphorous (ppm) 0.05 1.96 0.59
Antimony (ppb) <60 <60 <60
Arsenic (ppb) <10 72.2 14.31
Barium (ppb) <1 1,080 524.5
Beryllium (ppb) <5 <5 <5
Cadmium (ppb) <5 <5 <5
Chromium (ppb) <10 <10 <10
Copper (ppb) <10 123 <10
Iron (ppb) <100 23,600 8,726
Lead (ppb) <10 17.1 <10
Mercury (ppb) <0.2 <0.2 <0.2
Nickel (ppb) <40 <40 <40
Selenium (ppb) <35 <35 <35
Silver (ppb) <10 <10 <10
Thallium (ppb) <5 <5 <5
Zinc (ppb) <10 374 29.6
Source: (Louisiana Department of Environmental Quality 2005)
38 Atchafalaya National Wildlife Refuge
AIR QUALITY
The Clean Air Act (CAA) of 1970 (as amended in 1990 and 1997), required the EPA to implement air
quality standards to protect public health and welfare. National Ambient Air Quality Standards
(NAAQS) were set for six pollutants commonly found throughout the United States: lead, ozone,
nitrogen oxides (NOx), carbon monoxide (CO), sulfur dioxide (SO2), and particulate matter less than
10 and 2.5 microns in diameter (PM10 and PM2.5). The CAA establishes two types of NAAQS
standards – primary and secondary. Primary standa