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CHAPTER 2 ALTERNATIVES 

This chapter presents the alternative plan formulation process, alternative evaluation criteria, 

selected alternatives for detailed analysis and plan implementation and management. In order to 

ensure that sound decisions are made with respect to development of alternatives and plan 

selection, the plan formulation and selection process requires a systematic approach. This 

chapter documents this approach and ultimately the plan implementation and management. 

2.1 GENERAL 

The guidance for conducting Civil Works planning studies (ER 1105-2-100) requires the 

systematic development of alternative plans, which contribute to the Federal objective. In order 

to ensure that sound decisions are made with respect to development of alternatives and 

ultimately plan selection, the plan formulation process requires a systematic and repeatable 

approach. The Economic and Environmental Principles and Guidelines for Water and Related 

Land Implementation Studies (P&G) describe the USACE study process and requirements. 

They also provide guidance for the systematic development of alternative plans that contribute 

to the Federal objective. Alternatives for the proposed action were formulated with 

consideration of four criteria: completeness, effectiveness, efficiency, and acceptability. 

y Completeness is the extent to which a given alternative plan provides and accounts for 

all necessary investments or other actions to ensure the realization of the planned effects. 

y Effectiveness is the extent to which an alternative plan alleviates the specified problems 

and achieves the specified opportunities. 

y Efficiency is the extent to which an alternative plan is the most cost-effective means of 

alleviating the specified problems and realizing the specified opportunities, consistent 

with protecting the Nation’s environment. 

y Acceptability is the workability and viability of the alternative plan with respect to 

acceptance by state and local entities and the public and compatibility with existing 

laws, regulations, and public policies. 

The first phase of the plan formulation process is the initial problem identification. The second 

phase is a thorough evaluation of the resources within the project area and an assessment of 

what currently exists within the area compared to estimates of the change in those resources 

over time. This evaluation, or inventorying phase, accounts for the level or amount of a 

particular resource that currently exists within the study, i.e., the “Existing Conditions.” This 

phase also involves forecasting to predict what change(s) will occur to resources throughout the 

period of analysis, assuming no actions are taken to address the problems in the MRGO and 

Lake Borgne area, i.e., the conditions with the “No-Action Alternative.” Comparison of these 

two conditions of the project area measures the “Problems” resulting from the change in 

resources over time and identifies the “Needs” that must be addressed as a result of the 

problems. Study area “Problems” and resulting “Needs” are quantified based on this predicted 

change in resources. This second phase also results in the delineation of “Opportunities” that 

fully or partially address the “Problems and Needs” of the project area. An “Opportunity” is a 

resource, action, or policy that, if acted upon, may alter the conditions related to an identified 
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problem. An example “Opportunity” is the utilization of Lake Borgne water bottoms as a 

borrow source for wetland creation and nourishment. 

The third phase assesses potential “Opportunities” to generate alternative solutions. Alternative 

plans are then formulated across a range of potential scales to demonstrate the relative 

effectiveness of various approaches at varying scales. 

In the fourth phase, after alternative plans are developed, they are “Evaluated” for their potential 

results in addressing the specific problems, needs, and objectives of the study. The measure of 

output is expressed by the difference in amount or effect of a resource between the “No-Action 

Alternative” conditions and those predicted to occur with each alternative in place (future withproject conditions). This difference is referred to as the benefits of the alternative. The 

proposed action focuses on ecosystem benefits, which are measured in metrics that reflect the 

area, productivity, and value of wetlands that are rehabilitated, restored, or maintained to the 

extent practicable. 

The plan formulation process continues with the fifth phase, comparison of alternative plans to 

each other utilizing the benefit outputs and costs of the alternatives. A relationship between 

costs and varying levels of ecosystem restoration outputs across a full range of scales is 

compared. 

The sixth and final phase in the process is selection of the plan that best meets the study 

objectives and the P&G’s four criteria: completeness, effectiveness, efficiency, and 

acceptability. 

Using the six-phase alternative plan formulation process, the Selected Plan (SP) that best meets 

operation and maintenance objectives was developed. 

2.2 PLAN FORMULATION 

2.2.1 Overview 

Plan formulation is a dynamic process that begins with a broad scope, may change direction as 

new information or additional congressional guidance is obtained, and focuses on the most 

effective means of addressing the problem(s). This is accomplished as costs, benefits, and 

impacts of various options are more clearly defined. The alternative plan formulation rationale 

is typically used to identify and evaluate a range of alternatives that would fully or partially 

satisfy the planning, or, in this case, identified operations and maintenance objectives identified 

previously. 

2.2.2 Preliminary Alternative Plan Formulation 

In the initial response to the after-effects of Hurricanes Katrina and Rita in 2005, the USACE 

considered bank stabilization to protect the full length of the north and south banks of the 

MRGO navigation channel. Several bank stabilization methods and materials were initially 

considered, including sheetpile, rock dikes, and articulated concrete mattresses (ACM). 

Preliminary analysis indicated that sheet pile would not be as cost-effective as rock dikes or 

ACM. Therefore, preliminary alternative plan formulation centered on the potential placement 

of rock and ACM. Rock would be placed as foreshore dikes in front of the marsh, and ACM 
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would be placed directly on the shoreline, essentially armoring the bank on the channel side. 

Both techniques have been used successfully for shoreline stabilization on the MRGO. 

As additional guidance and direction on the supplemental authorizations was provided, the 

preliminary alternative plan formulation considerations were expanded to examine a wider 

scope of methods, materials and a larger area. Subsequently, the land bridge feature between 

the MRGO channel and Lake Borgne was considered. Restoring the land bridge that separates 

Lake Borgne from the MRGO navigation channel was identified as one of five near-term 

critical restoration areas in the LCA Plan, and was recommended by the Coast 2050 Plan 

(LCWCRTF & WCRA, 1999). 

Erosion rates along the Lake Borgne shoreline and the MRGO shoreline range from seven to 

24 feet (ft) (2.1 to 7.3 meters [m]) per year. Hence these areas were considered for potential 

construction of shoreline protection features. In addition, the fragmented wetlands within the 

land bridge area were considered for potential wetland creation and nourishment through the 

placement of borrow material. 

2.2.3 Environmental Operating Principles 

In 2002, the USACE reaffirmed its long-standing commitment to the environment by 

formalizing a set of Environmental Operating Principles (EOPs) applicable to decision-making 

in all programs. The principles are consistent with NEPA; the Department of the Army’s 

Environmental Strategy with its four pillars of prevention, compliance, restoration, and 

conservation; and other environmental statutes and Water Resources Development Acts 

(WRDA) that govern USACE activities. The EOPs have informed the plan formulation process 

and are integrated into all proposed program and project management processes. 

The EOPs are: 

1. Strive to achieve environmental sustainability, and recognize that an environment 

maintained in a healthy, diverse, and sustainable condition is necessary to support life. 

2. Recognize the interdependence of life and the physical environment, and proactively 

consider environmental consequences of USACE programs and act accordingly in all 

appropriate circumstances. 

3. Seek balance and synergy among human development activities and natural systems by 

designing economic and environmental solutions that support and reinforce one another. 

4. Continue to accept corporate responsibility and accountability under the law for 

activities and decisions under our control that impact human health and welfare and the 

continued viability of natural systems. 

5. Seek ways and means to assess and mitigate cumulative impacts to the environment and 

bring systems approaches to the full life cycle of our processes and work. 

6. Build and share an integrated scientific, economic, and social knowledge base that 

supports a greater understanding of the environment and impacts of our work. 

7. Respect the views of individuals and groups interested in USACE activities, listen to 

them actively, and learn from their perspective in the search to find innovative win-win 

solutions to the Nation’s problems that also protect and enhance the environment. 
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2.2.4 Planning Approach 

Alternatives were developed as a combination of features that would accomplish, to the 

maximum extent practicable, the Congressional mandate to repair, construct, or provide 

measures or structures necessary to protect, restore or increase wetlands, to prevent saltwater 

intrusion or storm surge in the MRGO area. Development of the TSP followed the following 

steps: 

1. Identify the problems 

2. Develop a suite of potential solutions 

3. Employ screening criteria 

4. Assemble alternative plan options 

5. Evaluate the alternative plans 

6. Select recommended plan 

2.3 DEVELOPMENT AND EVALUATION OF FEATURES 

2.3.1 Development of Alternative Plan Features 

Alternative plan features were initially identified through scoping; professional experience and 

judgment of the engineers and scientists comprising the Project Delivery Team (PDT) at the 

New Orleans District (CEMVN); previous work and studies conducted in the general area; 

restoration planning and construction efforts of other Federal, state, and local agencies such as 

the CWPPRA, Coast 2050, the LCA Study; and operations and maintenance activities 

conducted by the CEMVN. Features were developed as specific solutions that, when properly 

combined into alternative plans, would meet the project goals and objectives and be consistent 

with the Congressional mandate in the Third Supplemental Conference Report, Section 2304 in 

Title II, and Chapter 3 of the Fourth Emergency Supplemental Appropriations Act (P.L. 109-

234) “...for the repair, construction or provision of measures or structures necessary to protect, 

restore or increase wetlands, to prevent saltwater intrusion or storm surge.” 

Based upon these considerations, the PDT initially considered the following alternative plan 

features: wetland creation and nourishment, shoreline protection, surge barriers or wave breaks, 

ridge restoration, vegetative plantings, freshwater diversions, and saltwater barriers. 

2.3.1.1 Wetland Creation and Nourishment 

The PDT considered developing wetland creation and nourishment features based upon the fact 

that between the confluence of the MRGO with the GIWW (known as the “Golden Triangle”) 

and Shell Beach, there existed critical land bridges separating the MRGO navigation channel 

and the south shoreline of Lake Borgne that were in critical need of restoration. The PDT also 

considered the Coast 2050 Plan (LCWCRTF & WCRA, 1999) recommendations for specific 

wetland creation needs in the MRGO area, which were: 

y Stabilize the entire north bank of the MRGO using dredged material behind rock dikes 

along a 37-mile (59.5 km) reach; 

y Constrict the breaches in the marshes between the MRGO and Lake Borgne; and 

y Use dredged material from the MRGO to create marshes in South Lake Borgne, the 

Biloxi Marshes, and Eloi Bay. 
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Specific wetland creation and nourishment sites were further determined based upon previous 

environmental assessments and coastal restoration work in the area as well as examination of 

historic and current aerial photography of the area. Based upon these considerations, the PDT 

initially determined six locations in the MRGO and Lake Borgne critical land bridge area 

wherein wetland creation and nourishment would have the greatest potential benefits: 

1. Bayou La Loutre, 

2. Proctor Point, 

3. Doulluts Canal to Jahncke’s Ditch, 

4. Golden Triangle, 

5. Shell Beach, and 

6. South of Proctor Point. 

Initial designs for wetland creation and nourishment features included consideration of sitespecific retention methods (confined, semi-confined, unconfined). Generally, dredged material 

would be initially stacked to an elevation of about +3.2 ft (1.0 m) North American Vertical 

Datum of 1988 (NAVD88), with a target elevation of +0.5 to +1.5 ft (+0.2 to +0.5 m) NAVD88 

after dewatering and consolidation. Material required for construction of retention dikes and 

closures would be obtained from within the wetland creation cell. In the event soil borings and 

detailed design surveys should prove that earthen retention structures might not be viable in 

isolated situations, such as where a closure(s) was needed, then other structurally oriented 

means of closure/retention would be utilized where deemed necessary. This could include the 

use of stone or geotextile bags. In areas where retention would not be needed, dredged borrow 

material would be allowed to flow into surrounding existing fragmented wetlands to provide 

additional benefits through wetland nourishment. 

Borrow Sources 

The PDT also determined potential borrow sources for wetland creation and nourishment 

features. Use of the MRGO channel as a borrow source was considered to be contrary to the 

Congressional intent, as described in House Report No. 109-359, that funds provided in P.L. 

109-148 for authorized operation and maintenance activities along the MRGO not be used to 

conduct any dredging of the MRGO channel. Additionally, the use of the Mississippi River as a 

borrow source was also considered. Comments received on the Draft EIS has lead to further 

clarification as to why the Mississippi River was eliminated as a potential borrow source. 

Whereas the introduction of sediments from the Mississippi River would increase the total 

amount of sediment in the Lake Borgne system, the cost per unit associated with moving 

sediments from the river to the Lake Borgne land bridge would be much higher than using 

sediments from Lake Borgne water bottoms. Initial estimates indicate that the cost of using 

material from the Mississippi River would be 10.9 times higher than using material from the 

water bottoms of Lake Borgne. To reach the target of 2,650 acres (1,074 ha) that would be 

created or nourished by Alternative 10 (SP), the projected cost would be $196,357,000 to use 

the Mississippi River as a borrow source. Under Alternative 10 (SP), this cost is projected to be 

$18,000,000. Because of funding limitations associated with the authorization, and the need for 

more complete restoration of the land bridge, including features in other areas of the land 

bridge, the acreage of wetlands that could be created and nourished by the authorized 

appropriation would be reduced from 2,650 acres (1,074 ha) to 243 acres (98 ha). Hence, the 
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PDT determined that Lake Borgne water bottoms would be the most suitable and readily 

available source of borrow for construction of wetland creation and nourishment features. 

Borrow sites would be located a minimum of 3,000 ft (914 m) from the Lake Borgne shoreline 

to minimize potential impacts to hydraulic conditions (e.g., wave climate), as well as to avoid 

existing oyster leases to the maximum extent practicable. Borrow material would be excavated 

with a hydraulic dredge and transported to via pipeline to wetland creation and nourishment 

sites. Borrow sites would be excavated to a maximum depth of 20 ft (6.1 m) below the existing 

lake bottom. The dredge pipeline would be floated over lake bottoms to minimize potential 

adverse impacts to the benthos, including oysters. In some areas, nearshore floatation access 

channels may be required for equipment access. Floatation access channels would be 

constructed, as needed, with a bucket or clamshell dredge. All material dredged for floatation 

access would be stockpiled adjacent to the channel, to be returned to the channel following 

completion of construction activities. 

Borrow sites would be designed to minimize hypoxic (lack of dissolved oxygen) formation. 

Borrow sites would be pan-shaped with large surface areas (230 to 1,070 acres [91 to 433 ha]), 

relatively shallow depths (ten to 20 ft [3.0 to 6.1 m] below existing depth), and would gradually 

transition from adjacent water bottoms to project depth (side slopes between 

1 vertical : 2 horizontal and 1 v : 3 h). Proposed borrow sites would be located a minimum of 

approximately 3,000 ft (914 m) from shorelines and tidal passes which may potentially provide 

organic material (allochthonous) inputs that contribute to hypoxic conditions. In addition, 

sedimentation rates within the project area are relatively low without the presence of 

predominant organic layers. Moreover, circulation within Lake Borgne is not restricted by 

physical barriers, and storm fronts generating considerable wave energy commonly occur. 

Proposed borrow site dimensions, combined with observed characteristics of the project area are 

therefore not expected to favor the formation of hypoxic conditions. 

2.3.1.2 Shoreline Protection Features 

In developing shoreline protection features, the PDT considered the Coast 2050 Plan 

(LCWCRTF & WCRA, 1999) recommendations for shoreline protection features in the MRGO 

and Lake Borgne area, including: 

y Maintain the shoreline integrity of Lake Borgne by structural means (breakwaters, mats, 

rip-rap/stone, etc.) or non-structural means (vegetative geosynthetic turf/mats, vegetative 

plantings, etc.); and, 

y Stabilize the north bank of the MRGO using dredged material placed behind foreshore 

rock dikes. 

The PDT also considered the LCA Plan (USACE, 2004) recommendations that identified the 

MRGO and Lake Borgne area as one of five critical-needs areas in Louisiana and recommended 

construction of foreshore protection along 23 miles (37.0 km) of the north bank of the MRGO, 

and 15 miles (24.1 km) of shoreline protection along the southern shore of Lake Borgne. 

Based upon these considerations, the PDT determined shoreline and foreshore protection 

features should be designed to stabilize the existing Lake Borgne shoreline and the MRGO bank 

line in the critical land bridge area. Shoreline and foreshore protection features initially 

considered included: 
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y rock placement onshore or immediately offshore, 

y articulated concrete mattresses (ACM), 

y geotextile bags filled with sediment, 

y concrete panels, 

y sheetpiles, 

y vegetative plantings. 

Rock Placement: This feature would consist of either foreshore rock dikes or rock dikes placed 

near the existing shoreline to dissipate wave energy before it reached the shoreline. Foreshore 

rock dikes would be constructed by placing rock in a linear mound at the -1.5 to -2.0-foot (-0.5 

to -0.6 m) depth contour, to a height above the water’s surface. Nearshore rock dikes would be 

constructed in places where the bathymetry prohibits a foreshore dike (water deepens quickly 

from the shore). Floatation access channels would be required for rock placement. Material 

from the floatation channel could potentially be used to create a marsh platform between the 

rock dike and the existing shoreline, depending on how far from the shore it is constructed. 

Rock used for dike construction would be graded large enough to resist movement during highenergy events, such as frontal passages. 

Articulated Concrete Mattresses (ACM): This type of feature was considered as an alternative 

for bank line stabilization of the MRGO. Traditionally, ACM is used to stabilize deep draft 

channels, including both the Mississippi River and the MRGO, from erosion. The ACM 

provides a relative lightweight protective groundcover, which assures total bankline coverage 

when placed in underwater environments. It consists of 4 x 25-foot (1.2 x 7.6 m) sections or 

“squares” of three-inch (7.6 cm) thick concrete. Each square consists of smaller blocks cast 

upon a stainless steel fabric wire. These sections (squares) are tied to other squares, and are 

picked up as a unit to form a launch. Multiple launches are placed on the project area footprint, 

resulting in an erosion resistant blanket. The three-inch (7.6 cm) thick ACM protection does 

not provide any addition “height” for wave protection, as would a foreshore dike design. For 

this reason, the use of ACM was only considered for stabilization of the higher MRGO south 

bank for approximately two miles (3.2 km) immediately downstream of the existing hurricane 

protection levee, which ends at MRGO Mile 47. Also, placement of ACM for shoreline 

protection requires selective degrading of the bankline to remove irregularities to provide a 

stable, uniform slope. Extensive, undesired bankline preparation would have been required to 

place ACM along many proposed reaches of the Lake Borgne shoreline and the northern bank 

of the MRGO channel. 

Geotextile Bags: High strength woven geotextile tubes or bags would be filled with borrow 

sediments and placed in linear features along shorelines for erosion control. Geotextile bags, 

which can be prepared to various sizes, have been used for erosion control and construction of 

various types of structures in riverine and marine environments. Geotextile bags are often a 

very labor-intensive alternative for erosion protection, and often provide no economic savings 

verses rock alternatives. Geotextile bags are also susceptible to vandalism and deterioration 

from ultraviolet rays. As sand fill is the desired material for construction of this alternative, 

geotechnical considerations also play a major role in the determination of the feasibility and 

practicality of using geotextile bags. 

Concrete Panels: This feature consists of vertical concrete panels placed parallel to the 

shoreline and secured by vertical piles. They could provide potentially provide protection along 
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the MRGO north bank shoreline, where soil conditions, as well as topography, may make stone 

or ACM cost prohibitive and/or environmentally detrimental. However, due to previous costs 

analysis for this type of structure, as well as the uncertainty of the constructability of such 

features along the MRGO north bank and its ability to sustain surges from future hurricane 

events, it was not deemed a justified alternative feature for future consideration. Concrete 

panels are often more cost-effective in deeper water areas, where larger, heavier rock dike 

sections become more cost prohibitive and susceptible to future settlement. Concrete panels 

were considered as possible wave barriers in Lake Borgne, but this alternative was ruled out in 

favor of stone placement along the relative shallow Lake Borgne south shoreline. The rock 

design was more practical, provided more direct benefits to the adjacent wetlands, and better 

access to and from the lake for existing wildlife in the surrounding habitat. 

Sheetpile: Similar to concrete panels, sheet pile was also discussed as a possible means of 

shoreline protection along the MRGO north bank where soil conditions, as well as topography, 

may have made stone or ACM cost prohibitive and/or environmentally detrimental. However, 

due to potential cost and the uncertainty of the constructability of such feature along the MRGO 

north bank, as well as its ability to sustain surges from future hurricane events, it was not 

deemed as a justified alternative for future consideration. “Vertical” features in a wave 

environment result in greater scour at the toe of the structure, and do not provide the aesthetic or 

environmental benefits provided by other alternative solutions. 

Vegetative Plantings: Vegetative plantings, in addition to likely being a less costly solution, 

would provide some level of protection to existing wetlands and assist in the prevention of 

shoreline and bank erosion. However, as evidenced by the ongoing erosion of the existing 

wetlands, they would not provide the same level of protection to adjacent existing wetlands and 

infrastructure as would rock placement or other hard structures. 

Potential shoreline protection features were initially screened based upon the following criteria: 

1. Potential environmental impacts: shoreline protection features were preliminarily 

evaluated based upon their potential environmental impacts such as providing access for 

ingress and egress of aquatic organisms, minimizing direct construction impacts to 

existing wetlands, and others. 

2. Synergy: shoreline protection features were preliminarily evaluated with regard to their 

potential to increase the overall benefit of other proposed alternative plan features and to 

interact positively with other existing or authorized actions within the area (e.g., the 

CWPPRA shoreline protection projects PO-30 and PO-32). 

3. Geotechnical conditions: existing geotechnical data available for the MRGO/Lake 

Borgne area, along with prior design and construction knowledge of the project area, 

were used to assess potential shoreline protection features. For example, the north bank 

of the MRGO and surrounding vicinity are generally characterized as fragmented 

wetlands and shallow open water, with numerous areas of high organic composition not 

suitable for placement of ACM due to unacceptable impacts to existing fragmented 

wetlands and difficulty in anchoring the mattresses. Conversely, the south bank of the 

MRGO and surrounding vicinity was the original disposal site during initial construction 

and numerous subsequent maintenance dredging events in the channel, and has more 

consolidated substrates. As such, it is more suitable for installation of ACM. 
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4. Right-of-way: access and construction of shoreline protection features would require 

obtaining rights-of-entry and disposal easements from adjacent landowners. Oyster 

leases would either be avoided or, if necessary, extinguished/bought out by LDNR. 

Efforts were made to design shoreline protection features such that impacts to existing 

oyster leases would be minimized. 

Table 2.1 summarizes the shoreline protection materials and methods evaluated with respect to 

the above selection criteria. Preliminary screening determined that foreshore dikes could be 

installed along the north bank of the MRGO and the Lake Borgne shoreline and would include a 

foundation of geotextile fabric to provide additional foundation support where existing 

bathymetry allowed. Shoreline protection with foreshore dikes could be designed to create 

protected shallow open water habitats behind the dikes or as wetland creation sites. The most 

cost-effective alternative for foreshore protection along the north bank of the MRGO and 

shoreline protection along the Lake Borgne south shoreline is rock placement. Along the 

MRGO south bank, either ACM or rock, or some combination thereof, could be used. 

Preliminary screening determined that the potential environmental impacts of using sheetpile 

would likely include impeding tidal exchange as well as impeding ingress and egress of aquatic 

organisms to an unacceptable extent. The impacts of waves, generated during winter storms 

and tropical events in Lake Borgne, upon vertical walls would also pose a geotechnical and 

structural stability concern that would have to be addressed. Preliminary screening by the PDT 

also determined that the geotechnical properties of existing soils along the north bank of the 

MRGO would not be suitable for installation of ACM because there would be no effective way 

to anchor the mattresses. Proper installation of ACM would require significant excavation for 

aligning and accessing the Lake Borgne shoreline and would also be further complicated by the 

irregular bankline configuration and shallow conditions near the lake shoreline. These 

constraints could result in potentially adverse impacts to an unacceptable extent. Therefore, 

features utilizing ACM would be restricted to the south bank of the MRGO. 
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Table 2.1 Summary of Shoreline Protection Materials and Methods Considered 

Shoreline 

Protection 

Material 

and 

Method 

Environmental 

Impacts Synergy Right-of-Way Geotechnical Conditions 

Rock 

(foreshore 

placement) 

Reduces shoreline 

erosion; can be 

designed to provide 

ingress and egress 

for aquatic 

organisms as well as 

provide areas 

suitable for wetland 

creation and/or 

protected areas of 

shallow open water 

habitats between the 

rock dike and the 

existing natural 

shoreline 

Synergistic 

interactions with 

existing and 

authorized for 

construction 

projects such as 

CWPPRA PO-30 

and PO-32 projects 

and existing MRGO 

bank stabilization 

features would 

increase 

performance 

Foreshore dikes 

constructed in state 

water bottoms 

would require a 

Grant of Particular 

Use from the state 

of Louisiana 

Foreshore 

placement of rock 

along Lake Borgne 

and both the north 

and south banks of 

the MRGO are 

compatible with 

geotechnical 

foundations; Lake 

Borgne and MRGO 

north and south 

banks are generally 

suitable for 

construction 

Rock (onshore 

placement) 

Reduces shoreline 

erosion; covers and 

kills existing 

vegetation in 

footprint; restricts 

access of aquatic 

organisms to natural 

shoreline 

Synergistic 

interactions with 

existing and 

authorized for 

construction 

projects such as 

CWPPRA PO-30 

and PO-32 projects 

and existing MRGO 

bank stabilization 

features would 

increase 

performance 

Placement of rock 

along existing 

shorelines would 

require bank 

stabilization 

easements from 

private landowners 

Onshore placement 

of rock along Lake 

Borgne and both the 

north and south 

banks of the MRGO 

is compatible with 

geotechnical 

foundations; Lake 

Borgne and MRGO 

north and south 

banks are generally 

suitable for 

construction 

Articulated 

Concrete 

Mattresses 

(ACM) 

Reduces shoreline 

erosion; requires 

suitable soil 

substrate to tie into; 

covers and kills 

existing vegetation 

in footprint; requires 

more floatation than 

normal rock 

foreshore protection 

operations and 

significant shaping 

of existing shoreline 

Synergistic 

interactions with 

existing and 

authorized for 

construction 

CWPPRA PO-30 

and PO-32 projects 

and existing MRGO 

bank stabilization 

features would 

increase 

performance 

Placement of ACM 

along bankline 

would require bank 

stabilization 

easement from 

private landowner; 

placement of ACM 

in state water 

bottoms would 

require a Grant of 

Particular Use from 

the state of 

Louisiana 

South bank of 

MRGO is suitable, 

but Lake Borgne & 

north bank of 

MRGO tend to be 

low-lying marsh 

where ACM is not 

constructible due to 

high concentration 

of organics in the 

soils along the 

MRGO north bank; 

Requires additional 

bank grading 

thereby increasing 

impacts to wetlands 

and water bottoms 
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Shoreline 

Protection 

Material 

and 

Method 

Environmental 

Impacts Synergy Right-of-Way Geotechnical Conditions 

Geotextile 

Bags 

(foreshore and 

onshore 

placement) 

Reduces shoreline 

erosion; foreshore 

placement may be 

designed to provide 

areas suitable for 

wetland creation via 

dredged material 

disposal within 

protected shallow 

waters 

Synergistic 

interactions with 

existing and 

authorized for 

construction 

CWPPRA PO-30 

and PO-32 projects 

and existing MRGO 

bank stabilization 

features would 

increase 

performance 

Placement of 

geotextile bags 

along bankline 

would require bank 

stabilization 

easement from 

private landowner; 

placement of 

geotextile bags in 

state water bottoms 

would require a 

Grant of Particular 

Use from the state 

of Louisiana 

Lake Borgne and 

MRGO north and 

south banks are 

suitable for 

placement; filling 

material is limiting 

factor; extremely 

heavy making 

transporting 

difficult; susceptible 

to vandalism and 

UV rays 

Concrete 

Panels 

Reduces shoreline 

erosion; can be 

designed to provide 

ingress and egress 

for aquatic 

organisms; creates 

an artificially steep 

shoreline that could 

have wave erosion 

problems at base 

Synergistic 

interactions with 

existing and 

authorized for 

construction 

CWPPRA PO-30 

and PO-32 projects 

and existing MRGO 

bank stabilization 

features would 

increase 

performance 

Concrete panels 

constructed in state 

water bottoms 

would require a 

Grant of Particular 

Use from the state 

of Louisiana 

Concrete panels 

along Lake Borgne 

and both the north 

and south banks of 

the MRGO are 

compatible with 

geotechnical 

foundations; 

uncertainty exists 

for the 

constructability of 

such feature along 

the MRGO north 

bank and its ability 

to sustain surges 

from future 

hurricane events; 

considered for Lake 

Borgne and MRGO 

north and south 
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Shoreline 

Protection 

Material 

and 

Method 

Environmental 

Impacts Synergy Right-of-Way Geotechnical Conditions 

Sheetpile 

Reduces shoreline 

erosion; may 

impede tidal 

exchange and 

ingress and egress 

of aquatic 

organisms 

Synergistic 

interactions with 

existing and 

authorized for 

construction 

projects such as 

CWPPRA PO-30 

and PO-32 projects 

and existing MRGO 

bank stabilization 

features would 

increase 

performance 

Placement of 

sheetpile along 

bankline would 

require bank 

stabilization 

easements from 

private landowners; 

installation of 

sheetpile in state 

water bottoms 

would require a 

Grant of Particular 

Use from the state 

of Louisiana 

Greater 

constructability than 

rock where banks 

are either too steep 

or the water is very 

deep; conditions 

change so rapidly 

that planning for 

sheetpile utilization 

is extremely 

difficult; does not 

perform well in 

highly organic soils; 

and is more 

susceptible to 

impacts from storm 

surge from Lake 

Borgne 

Vegetative 

Plantings 

Provides nonstructural alternative 

to shoreline 

protection; may 

provide a source for 

revegetation of 

adjacent wetlands; 

may trap sediments 

to increase marsh 

area 

Synergistic 

interactions with 

proposed wetland 

creation and 

nourishment 

features would 

increase 

performance 

Would require 

wetland creation 

and restoration 

easements for 

private landowners 

Lake Borgne 

shoreline and 

MRGO north and 

south banks are 

suitable for 

vegetative 

plantings; as 

evidenced by the 

ongoing erosion of 

the existing 

wetlands, they 

would not provide 

the same level of 

protection to 

adjacent existing 

wetlands and 

infrastructure as 

would rip rap or 

other hard structures

2.3.1.3 Surge Barriers and/or Wave Breaks 

Surge barriers and/or wave breaks were considered for implementation in both the southeastern 

and southwestern lobes of Lake Borgne. A series of offshore terrace-like structures would be 

constructed from material either imported or dredged from the adjacent Lake Borgne water 

bottom to reduce wind-driven waves before they reach the shorelines. However, preliminary 

assessment indicated these features would not meet the following planning objectives and 

constraints: restore existing wetlands, reduce saltwater intrusion, prevent the coalescence of 

Lake Borgne and MRGO, or support other restoration plans. 
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FEIS June 2009 

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2.3.1.4 Ridge Restoration 

Restoration of the remnant portions of the Bayou La Loutre ridge was considered. This feature 

would not restore that portion of the Bayou La Loutre ridge removed during construction of the 

MRGO. Rather, this feature would restore those existing portions of a critical natural 

geomorphic feature in the area through the placement of material, either imported or obtained 

from the water bottoms of Lake Borgne, to an elevation that would support upland wooded 

vegetation. However, preliminary assessment indicated ridge restoration would not meet the 

following planning objectives and constraints: restore existing wetlands, reduce storm surge or 

saltwater intrusion, or prevent the coalescence of Lake Borgne and MRGO. Ridge restoration is 

being considered under the ongoing LACPR Study. 

2.3.1.5 Vegetative Plantings 

The Coast 2050 Plan (LCWCRTF & WCRA, 1999) recommended vegetative plantings of 

cypress and/or marsh grass in nearly all areas of the Lake Pontchartrain Basin, including the 

MRGO area, to restore wetlands, provide more natural shoreline protection, and prevent 

continued marsh deterioration. 

Vegetative plantings for shoreline and wetland protection were considered. Rows of salttolerant marsh grasses, such as smooth cordgrass (Spartina alterniflora), could be planted near 

the shoreline to reduce wave energy. However, preliminary assessment of this labor-intensive 

feature indicated vegetative plantings would not perform well in the high-energy environment 

near the Lake Borgne shoreline. Consequently, vegetative plantings would not meet the 

planning objectives and constraints: protect or restore existing wetlands, reduce storm surge or 

saltwater intrusion, or prevent the coalescence of Lake Borgne and MRGO. 

2.3.1.6 Freshwater Diversions 

Complete designs for freshwater diversions from the Mississippi River at several potential 

locations were considered: Violet, Bayou La Loutre, Caernarvon East, and the Inner-Harbor 

Navigation Canal. Freshwater introduction would meet the planning objective of preventing 

saltwater intrusion, and indirectly would increase productivity of wetlands. However, 

preliminary assessment indicated freshwater diversions would not meet the following planning 

objectives and constraints: protect existing wetlands from erosion, reduce storm surge, prevent 

the coalescence of Lake Borgne and MRGO, or be constructed within the near-term. Diversion 

alternatives are currently being considered under the ongoing LACPR Study. 

2.3.1.7 Saltwater Barriers 

Saltwater barriers, including construction of submerged sills somewhere along the MRGO, 

construction of a total closure structure near Bayou La Loutre, and construction of a gated 

structure somewhere along the MRGO were considered. These features would meet the 

planning objective of preventing saltwater intrusion. However, the ongoing MRGO Deep-Draft 

Deauthorization Study was considering these features. The June 5, 2008, Integrated Final 

Report to Congress and Legislative Environmental Impact Statement for the MRGO Deep-Draft 

Deauthorization Study recommended construction of a total closure structure across the MRGO 

near Bayou La Loutre. Construction of the closure structure is anticipated to be completed 

before the beginning of the 2009 hurricane season. 
Chapter 2 Alternatives 

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2.3.2 Screening Alternative Plan Features 

Screening criteria were developed by the PDT to select potential alternative plan features 

(Table 2.2) that would: 

1. Be consistent with Congressional direction authorized by Chapter 3, under division B, of 

title I of Public Law 109-148 (119 Stat. 2762) under the heading ‘Operations and 

Maintenance,’ as amended by Section 2304 of Public Law 109-234 (120 Stat. 418); 

2. Be consistent with the EOPs; and, 

3. Be able to be combined into alternative plans that would best meet planning objectives 

and goals. 

The primary screening criterion was whether or not the feature would meet the legislative 

authority (Public Law 109-234) necessary “...to protect, restore or increase wetlands, to prevent 

saltwater intrusion or storm surge.” Additional screening criteria included: 

1. The construction time frame; 

2. The level of protection the proposed feature would provide to the land bridge; and, 

3. The level of completion of previous evaluations of a proposed feature. 

It was paramount that alternative plan features were supportive of previous coastal restoration 

and other planning efforts (e.g., Coast 2050, LCA, CWPPRA, Louisiana State Master Plan, 

etc.); and would complement other existing or authorized-for-construction projects. Time 

constraints, cost effectiveness, and previous NEPA clearance of an area were also examined. 

Areas for which NEPA compliance requirements for similar actions were completed or would 

be completed in a relatively short period of time were rated more favorably than features for 

which extensive NEPA compliance efforts would be required. An additional screening criterion 

was how well the proposed feature would perform and protect adjacent populations and 

infrastructure outside the project area. 
Chapter 2 Alternatives 

FEIS June 2009 

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Table 2.2 Alternative Plan Features Initially Developed 

Construction Design – Assessment 

Wetland Creation and Nourishment/

Vegetative Plantings

Salt Water Barrier

Bayou La Loutre Design Dam at Bayou La Loutre 

Proctor Point Design MRGO Gates 

Doulluts Canal to Jahncke’s Ditch Submerged Sills 

Golden Triangle 

Shell Beach Surge Barrier or Wave Breaks

South of Proctor Point SE lobe of Lake Borgne 

 SW lobe of Lake Borgne 

Shoreline Protection/ Vegetative Plantings

Lake Borgne Reach #3 (already awarded) Freshwater Diversion

Golden Triangle (B. Bienvenue to B. Gentilly) Assess Violet FW Diversion 

Bayou Dupre Constriction Assess Bayou La Loutre 

Bayou Dupre Flanking Shorelines Assess Caernarvon East 

Proctor Point Assess IHNC River Diversion 

West of Shell Beach 

(West of CWPPRA PO-30) 

Shoreline Restoration Fronting MRGO Levees Ridge Restoration

MRGO Shoreline at Shell Beach 

(Mile 40 to Mile 44.5) (already awarded) 

Bayou La Loutre Ridge Restoration 

Demonstration 

CWPPRA PO-32 Extension 

2.3.3 Features Having Major Value 

After initial screening, three features were found to have greater potential for success than the 

other features. Based on the alternative plan feature screening criteria, wetland creation and 

nourishment and shoreline protection features had greater potential for meeting project goals 

than the other features. Shoreline protection techniques that were deemed promising enough for 

more detailed analysis included foreshore rock dikes and ACM. 

The wetland creation and nourishment, foreshore rock dike, and ACM features were examined 

using the screening criteria outlined above. These criteria were applied to the various potential 

sites for these features to provide an added level of detail for decision-making. Features were 

rated, on a scale from 0 to 5, on how well they met each screening criteria; ratings were then 
Chapter 2 Alternatives 

FEIS June 2009 

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summed for each feature. This approach provided a basis for identifying features that would 

most likely be effective and should be included in alternative plans. 

Alternative plan feature screening criteria included: 

y Acres created and protected: < 100 acres = 1 point; 101-1,000 acres = 3 points; 

> 1,001 acres = 5 points. 

y Cost per acre: < $25,000 per acre = 5 points; $25,001 to $50,000 per acre = 4 points; 

$50,001 to $75,000 per acre = 3 points; $75,001 to $100,00 per acre = 2 points; 

> $100,000 per acre = 1 point. 

y Salinity reduction: contributes to salinity reduction = 5 points; contributes somewhat to 

salinity reduction = 2 points; does not contribute to salinity reduction = 0 points. 

y NEPA clearance of site: NEPA clearance complete for the site = 5 points; minor NEPA 

clearance work required = 3 points; Environmental Assessment needed for site = 

1 point; Environmental Impact Statement Required = 0 points. A potential savings in 

time could be realized if an environmental assessment (EA or EIS) of similar actions had 

previously been completed (e.g., cultural resources surveys, hazardous waste surveys, 

etc.) for a particular area. 

y Land bridge protection: Protects the critical land bridge between Lake Borgne and the 

MRGO channel = 5 points; Does not protect the land bridge = 0 points. 

y Proximity to critical populations and infrastructure: feature is proximate to critical 

populations and infrastructure = 5; feature is somewhat proximate to critical populations 

and infrastructure = 3; feature is not proximate to critical populations and infrastructure 

= 0 points. 

y Storm abatement and wave reduction: feature contributes greatly to storm abatement 

and wave reduction = 5 points; feature contributes somewhat to storm abatement and 

wave reduction = 1 to 4 points, depending on the level of contribution; feature does not 

contribute to storm abatement and wave reduction = 0 points. 

y Synergy with existing or authorized for construction projects: feature complements 

other projects = 5 points; feature does not complement other projects = 0 points. 

Constraints to potential alternative plan features considered included: the presence of oyster 

leases, the need for a borrow source, the potential for the presence of cultural resources that 

would require avoidance, disruption of recreation activities, disruption of essential fish habitat, 

floatation channel access needed, real estate acquisition needed, and potential hazardous, toxic, 

and radioactive wastes (HTRW) issues. The presence of each constraint contributed a point, 

which was subtracted from the total for the criteria. The results are presented in Table 2.3. 

2.3.3.1 Wetland Creation and Nourishment 

Wetland creation and nourishment was considered for six locations (Table 2.2). These features 

would include the construction of retention dikes, where needed, to contain the hydraulically 

dredged material to facilitate stacking to an elevation that would support wetland vegetation and 

to minimize adverse impacts to water quality. 
Chapter 2 Alternatives 

FEIS June 2009 

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2.3.3.2 Shoreline Protection Features 

Shoreline protection features were considered for nine locations (Table 2.2). These features 

would stabilize the shoreline by reducing wind- and wake-driven wave erosion. Two 

techniques for shoreline protection were retained for further analysis. 

Foreshore rock dikes would be constructed at the -1.5 to -2.0-foot (-0.5 to -0.6 m) depth contour 

by placing rock in a linear mound to a height above the water’s surface to dissipate wave energy 

before it reached the shoreline. Floatation access channels would be required for rock 

placement. 

Placement of ACM would armor the shoreline, protecting the underlying sediments from 

erosion. The mattresses would be installed with a barge-mounted crane from the water, so some 

floatation channels may be required. Heavy equipment would also be required onshore to 

anchor the mattresses. 

2.3.4 Features Having Limited or No Value 

Features that would have limited value in meeting the project goals included freshwater 

diversions, vegetative plantings, salt-water barriers, surge barriers and sills, and ridge 

restoration. Some shoreline protection marsh creation features were also identified that would 

have limited value in meeting the project goals. These features, and the reasons they were 

screened from further consideration are presented in Table 2.4. 
Chapter 2 

FEIS 

2 – 18

Table 2.3 Sorting Criteria and Ratings of Features Used for Preliminary Screening 

Project Type / Name Acres

Cost 

($ mill) 

Cost per 

Acre 

Acres created / protected 

Cost per Acre 

Salinity Reduction 

NEPA Status 

Land Bridge Protection 

Proximity to Critical 

Populations and Infrastructure 

Storm abatement wave 

reduction 

Synergy with Other Projects 

Constraints* 

Total Commen

Wetland Creation

Bayou La Loutre 985 15 $15,228 3 5 0 1 0 0 3 5 4 13 Synergy w

Constrain

Proctor Point 720 9.1 $12,639 3 5 0 1 0 0 0 0 4 5 Synergy w

Constrain

Doulluts to Jahncke’s 2000 28 $14,000 5 5 0 1 0 0 0 5 5 11 ConstrainGolden Triangle 2850 20.8 $7,298 5 5 0 1 5 5 5 5 6 25 ConstrainMRGO North Bank NEPA 

Cleared Beneficial Use Sites (Shell Beach Area) 

920 12.4 $13,478 5 5 0 5 5 3 1 5 5 24 Constrain

Critical Shoreline Protection 

Golden Triangle 80 7.8 $97,500 1 2 0 1 5 5 5 5 4 20 ConstrainLake Borgne Tie-In to PO-32 

(REACH D) 54 7 $129,630 1 1 0 1 0 0 3 5 4 7 Constrain

Proctor Point 44 8.2 $186,364 3 1 0 1 0 0 0 0 3 2 ConstrainLake Borgne West of Shell Beach 

(REACH C) 36 9.2 $255,556 1 1 0 3 5 5 3 5 4 19 Constrain

Lake Borgne Vicinity Bayou 

Bienvenue (REACH A) 42 6.25 $148,810 1 1 0 3 5 5 5 5 3 22 Constrain

Lake Borgne Vicinity Bayou 

Dupre (REACH B) 33 8.5 $257,576 1 1 0 3 5 5 5 5 4 21 Constrain

MRGO Bank Armoring and 

Levee Protection (AMC Mi 45-47) 

25 2.3 $92,000 1 2 0 1 0 3 3 5 0 15 No constr
Chapter 2 

FEIS 

2 – 19

Project Type / Name Acres

Cost 

($ mill) 

Cost per 

Acre 

Acres created / protected 

Cost per Acre 

Salinity Reduction 

NEPA Status 

Land Bridge Protection 

Proximity to Critical 

Populations and Infrastructure 

Storm abatement wave 

reduction 

Synergy with Other Projects 

Constraints* 

Total Commen

MRGO North Bank (MI 40-46) 257 14 $54,475 3 3 0 5 5 5 3 5 3 26 ConstrainBayou Dupre Closure 0 5 $0 1 5 0 1 5 5 3 5 5 20 Constrain

Recommended Plan Features 

Golden Triangle (rescaled) 2650 17.1 $6,453 5 5 0 1 5 5 5 5 6 25 ConstrainMRGO N Bank NEPA Cleared 

Beneficial Use Sites (rescaled) 520 7.5 $14,423 3 5 0 1 5 3 1 5 5 18 Constrain

Lake Borgne West of Shell Beach 

(REACH C) (rescaled) 90 7.5 $83,333 1 2 0 3 5 5 3 5 4 20 Constrain

Lake Borgne Vicinity B. 

Bienvenue (REACH A) (rescaled) 

106 6.25 $58,962 3 3 0 3 5 5 5 5 3 26 Constrain

Lake Borgne Vicinity B. Dupre 

(REACH B) (rescaled) 63 6.5 $103,175 1 1 0 3 5 5 5 5 4 21 Constrain

MRGO North Bank (MI 40-46) 

(rescaled) 480 10 $20,833 3 5 0 5 5 5 3 5 3 28 Constrain

*Constraints: a=oyster; b=borrow source; c=cultural; d=recreation; e=essential fish habitat; f=floatation; g=real estate; h=H
Chapter 2 Alternatives 

FEIS June 2009 

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Table 2.4 Measures Removed from Further Consideration 

Measure Removed Reason for Removal 

Lake Borgne Reach #3 

(already awarded) 

This feature has already been awarded for construction as part a 

continuing Operations and Maintenance authority, so it is 

unnecessary to include as part of this project. 

Shoreline Restoration 

fronting MRGO levees 

(B. Dupre blowout) 

This feature can be addressed through modification to the existing 

south shore stone dike contract, so it is unnecessary to continue as 

part of this project. 

Bayou Dupre Land 

Bridge Restoration 

This feature would conflict with the Lake Borgne Shoreline 

Protection (CWPPRA PO-30) project, which has been awarded for 

construction. 

Bayou La Loutre Ridge 

Restoration Demo 

Long-term performance and benefits are unknown for this demo 

project, and it would not meet the project goals (see 

Section 2.3.1.4). 

MRGO Sill Vicinity 

Bayou La Loutre 

Salinity benefits would be minimal without a total closure, and it 

would not meet the project goals of protection of existing wetlands, 

and preventing the coalescence of MRGO and Lake Borgne. 

Vegetative Planting 

Vegetative plantings would be unsuitable for high wave energy 

areas characteristic of the project area, and expensive for the level 

of protection provided. 

Bayou Dupre Marsh 

Creation 

Similar project recently completed and marsh appears intact, so 

further restoration for this area would not be cost-effective. 

Bayou Dupre Critical 

Shoreline Protection 

This feature would conflict with the Lake Borgne Shoreline 

Protection (CWPPRA PO-30) project, which has been awarded for 

construction. 

Lena Lagoon Area 

Marsh Creation 

Wetland creation in this area would not meet the project goal of 

preventing the coalescence of MRGO and Lake Borgne as 

effectively as other marsh creation features. No NEPA clearance on 

the site started. 

Bayou La Loutre 

Diversion 

Currently being investigated under LCA, so it is unnecessary to 

continue as part of this project. 

Caernarvon East 

Diversion Project 

Currently being investigated under LCA, so it is unnecessary to 

continue as part of this project. 

MRGO North Bank 

(Mile 40-46) 

This feature has already been awarded for construction as part a 

continuing Operations and Maintenance authority, so it is 

unnecessary to include as part of this project. 
Chapter 2 Alternatives 

FEIS June 2009 

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2.4 DEVELOPMENT AND SCREENING OF 

ALTERNATIVE PLANS 

2.4.1 Development of Alternative Plans 

Preliminary screening of alternative plan features by the PDT determined four wetland creation 

and nourishment features and nine shoreline protection features would have the least 

constraints, be consistent with the EOPs, be synergistic with other existing and authorized 

projects, and could most effectively be combined into alternative plans that would best meet 

planning objectives. These features were then combined into ten alternative plans. 

Construction costs for each alternative plan was set at a total of about $52 million. This would 

allow an initial reserve of $20 million for construction contingency, supervision and 

administration (S&A), engineering data collection, NEPA compliance, labor, and design or 

study efforts. Various combinations and sizes of wetland creation and nourishment and 

shoreline protection features were then developed and evaluated to determine the best 

combinations of features that would meet the planning objectives. 

2.4.2 Description of Alternative Plans 

Ten alternative plans, with various combinations of wetland creation and nourishment and 

shoreline protection features, were developed and evaluated following preliminary screening of 

features. Alternative plans were assembled by combining features that scored highly in the 

preliminary screening and would have positive synergistic interactions with other features 

within the alternative plan. Protection of the critical MRGO and Lake Borgne land bridge and 

synergistic interaction with existing and authorized for construction projects (e.g., CWPPRA 

projects PO-30 and PO-32 as well as existing O&M projects) in the project area increased the 

value of features for inclusion in alternative plan formulation. Additionally, project features 

were chosen to complement each other to more completely protect the land bridge. Specific 

features of each alternative plan are presented in Table 2.5. Features were grouped into plans to 

provide comprehensive benefits to the project area. Features were also scaled after selection to 

maximize the use of funds available; thus, the specifications of each feature may differ among 

the different plans in which it is included (Table 2.5). 

Initial evaluation of these ten alternative plans examined how well the combination of features 

would protect the critical land bridge and complement existing projects, as well as meet the 

other sorting criteria. The three plans that best met these criteria would be retained for detailed 

analysis, which would assist with the selection of a recommended plan. 

2.4.3 Plans Not Carried Over for Detailed Analysis 

Seven plans were not carried over for detailed analysis because they did not fully satisfy the 

sorting criteria presented in Table 2.3 or the planning goals and objectives presented in 

Section 1.4. Although the features in these plans would provide significant benefits, those plans 

not carried over for detailed analysis did not adequately address the sorting criteria, or planning 

objectives and goals. Specifically, Plans 1, 4, 5, 6, 7, 8, and 9 were not carried forward for 

detailed analysis, for the following reasons: 

y Plan 1 would result in relatively fewer acres created or restored as well as the total acres 

protected. 
Chapter 2 Alternatives 

FEIS June 2009 

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y Plan 4 had most of the same features as Plan 10, but did not include wetland creation 

and restoration in the Shell Beach area, and therefore wasn’t as effective as Plan 10 in 

protecting the entire land bridge. 

y Plan 5 had most of the same features as Plan 10, but did not include wetland creation 

and restoration in the Shell Beach area, and therefore wasn’t as effective as Plan 10 in 

protecting the entire land bridge. 

y Plan 6 included restoration activities at Proctor Point, but not near the thin isthmus near 

Shell Beach, which would be less effective at meeting the goal of protecting the land 

bridge than other plans. The plan features would also be farther from critical 

populations, and would not synergistically complement other restoration activities on the 

land bridge. 

y Plan 7 also included restoration activities at Proctor Point, but included shoreline 

protection near Shell Beach. It would not be as cost effective, however, and would 

create and restore fewer total acres of wetlands. 

y Plan 8 would create more acres of wetlands than the other plans, and would be very cost 

effective, but would not protect the land bridge as effectively as other plans. Also, most 

of the project features would be farther removed from critical populations, and would 

not protect existing wetlands or shorelines as well as other plans. 

y Plan 9 did not include any features in the western lobe of Lake Borgne, and so did not 

provide adequate protection to the critical land bridge. The total acreage of wetlands 

created and restored was low, and the plan features would not protect existing wetlands 

as well as other plans. The project features were also more removed from critical 

population centers than other plans. 

Table 2.5 Combinations and Specifications of Wetland Creation and Nourishment (WC) 

and Shoreline Protection (ShP) Features Included in the Ten Alternative Plans 

Alternative Plan Options 

Feature 1 2 3 4 5 6 7 8 9 10 

Wetland Creation and Nourishment (combined initial acreage) 

Golden Triangle WC 2,850 ac 2,850 ac 2,750 ac 2,650 ac 2,850 ac 2,850 ac 2,850 ac 2,850 ac 2,650 ac

Shell Beach WC 920 ac 920 ac 695 ac 

Proctor Point WC 700 ac 

Doulluts-Jahncke’s Ditch WC 2,000 ac 2,000 ac 

Shoreline Protection (linear feet) 

Golden Triangle ShP 17,700 ft 17,700 ft 

B. Bienvenue Vicinity ShP (A) 13,200 ft 16,230 ft 16,230 ft 13,200 ft 13,200 ft 13,200 ft 13,200 ft 16,230 ft

B. Dupre Vicinity ShP (B) 17,650 ft 18,000 ft 9,950 ft 18,000 ft 18,000 ft 17,650 ft

West of Shell Beach ShP (C) 19,500 ft 15,400 ft 15,400 19,500 ft 19,500 ft 19,500 ft 19,500 ft 15,400 ft

MRGO ACM (South Shore) 10,840 ft 10,840 ft 10,840 ft 

Proctor Point ShP 15,400 ft 15,400 ft 

PO-32 extension ShP 15,000 ft 

When the ten alternative plans were assessed by the PDT, it was a general consensus among the 

PDT that the features proposed under Alternative 10 would provide the greatest environmental 

and ecosystem benefits, as well as assist in the CEMVN’s mission to reduce storm surge 
Chapter 2 Alternatives 

FEIS June 2009 

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impacts upon the St. Bernard and Orleans Parish areas. Alternatives 2 and 3 provided similar 

benefits. The benefits that would be derived from these three alternatives stood out among the 

remaining seven alternative plans for the reasons described above. In general, plans that 

resulted in total marsh creation (Alternative 8), total shoreline protection (Alternative 9), or 

isolated areas of protection (Alternative 6 and Alternative 7) did not provide as comprehensive a 

plan as the other alternatives. Plans that provided marsh creation in areas of unprotected 

shoreline (Alternative 8) were considered not as practical as other alternatives. Finally, it was 

realized that the features contained in both Alternative 4 and 5 could be resized to afford 

additional marsh creation at the Shell Beach site, resulting in development of the preferred 

Alternative 10 plan. Based on the reasons detailed above, Plans 2, 3, and 10 were identified as 

best meeting the planning goals and objectives. These plans were retained for detailed analysis. 

2.4.4 Alternative Plans Retained for Detailed Analysis 

Plans 2, 3, and 10 best met the planning goals objectives, and were analyzed in greater detail to 

allow a more thorough comparison of potential benefits. A summary of alternative plan features 

is presented in Table 2.6. 

Alternative plan benefits were measured in three ways: 

1. The initial acres created/protected/restored were calculated as the sum of the acres for 

wetland creation and shoreline protection features. For the wetland creation features, the 

initial acreage included the acres created as well as the acres nourished. For shoreline 

protection features, the initial acreage was the area that would erode over the period of 

analysis in the No-Action Alternative. This was calculated by multiplying the historic 

erosion rate by 50 years, and multiplying that number by the feature length to get the 

area protected. 

2. The net acres created/protected/restored were calculated by subtracting the projected 

acreage at the end of the period of analysis (Year 50) for the No-Action Alternative from 

the acreage projected to exist for each Alternative Plan under the Future With Project 

condition. 

3. The average annual habitat units (AAHU), which is detailed in the following paragraph. 

The AAHUs were calculated using the Wetland Value Assessment (WVA) Models developed 

by the USFWS. The WVA Models are a modification of USFWS Habitat Evaluation 

Procedures (HEP) which are widely used by the USFWS and other agencies to evaluate the 

impacts of development projects on fish and wildlife resources. While the HEP Models utilize a 

species-specific approach, the WVA Models utilizes a community-level approach. Communitylevel, mathematical models were developed specifically for each marsh type (i.e., freshintermediate, brackish and saline) in coastal Louisiana. In addition to marsh community 

models, additional models have also been developed for barrier islands, barrier headlands, 

swamp, bottomland hardwoods and forested coastal ridges (e.g., coastal chenier) habitats. Each 

WVA Model contains habitat variables that are weighted in each mathematical model, based on 

their importance to habitat quality. Project evaluations involve data collection to determine 

baseline habitat conditions, and prediction of habitat conditions for future with-project and 

future without-project scenarios. The salt marsh and brackish marsh models were used in the 

analysis of benefits for the features in the alternative plans retained for detailed analysis, and the 

totals for the alternative plans were compared to the No-Action Alternative. 
Chapter 2 Alternatives 

FEIS June 2009 

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Parameters used for the analysis for the salt marsh and brackish marsh models included the 

percentage of the project area that is covered by emergent vegetation, the percentage of open 

water bottoms covered with submerged aquatic vegetation, the marsh interspersion (a measure 

of marsh-edge habitat), the percentage of open water that is less than 1.5 ft (0.5 m) deep, 

average salinity, and accessibility for aquatic organisms (Louisiana Coastal Wetlands 

Conservation and Restoration Task Force, 2006). For each plan feature, predictions for each 

parameter were made for the No-Action Alternative and each Alternative Plan at significant 

times over the period of analysis, such as at the beginning and at the end of maintenance 

episodes, or when vegetation is anticipated to be planted or become established. A formula 

converted the parameters into a single metric, a community habitat suitability index for that 

habitat type. This index was applied to the acreages present to determine the number of habitat 

units present at that snapshot in time. The habitat units were averaged over the period of 

analysis to generate one number – the net average annual habitat units (AAHU) for each feature, 

which were summed for the features in each plan to provide the plan’s total net benefit 

(Louisiana Coastal Wetlands Conservation and Restoration Task Force, 2006). 

2.4.4.1 Plan 2 Summary 

Plan 2 would create 1,500 acres (608 ha) and nourish 1,350 acres (547 ha) of brackish marsh in 

the Golden Triangle (Figure 2.1). Plan 2 would also construct five shoreline protection 

features. Foreshore rock dikes would be located along the Lake Borgne shoreline in the Golden 

Triangle area (17,700 linear ft [lf]; 5,395 m) to protect 223 acres (90 ha); in the vicinity of 

Bayou Bienvenue (16,230 lf; 4,946 m) to protect 186 acres (75 ha); in the vicinity of Bayou 

Dupre (17,650 lf; 5,379 m) to protect 142 acres (58 ha); and west of Shell Beach (15,400 lf; 

4,694 m) to protect 194 acres (79 ha). One shoreline protection feature would consist of the 

installation of ACM between Mile 45 and Mile 47 along the southern shoreline of the MRGO 

(10,840 lf; 3,304 m) to protect 301 acres (122 ha). These shoreline protection features would 

protect a total of 1,046 acres (424 ha) of adjacent fragmented wetlands from degradation and 

wave erosion. Plan 2 would require a total 9.5 million cubic yards (cy) (7.3 million cubic 

meters) of borrow for wetland creation and nourishment that would be removed from 

approximately 1,070 acre (433 ha) of Lake Borgne water bottoms (Figure 2.1). Plan 2 would 

place a total of 284,350 square yards (sq yd) (238,020 sq m) of geotextile fabric and 

548,200 tons (541,432 metric tons) of rock for the Lake Borgne shoreline protection features, 

and 24,600 tons (24,296 metric tons) of crushed rock and 10,840 lf (3,304 m) of ACM along the 

MRGO shoreline. A total of 186.2 acres (75.4 ha) of Lake Borgne and MRGO water bottoms 

would be dredged for floatation access. Material dredged for floatation access would be used 

beneficially to the maximum extent practicable to create wetlands between the shoreline 

protection dike and the shoreline, or temporarily stockpiled adjacent to the floatation channel in 

open water and returned to the channel following completion of construction features.
Chapter 2 

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Table 2.6 Details of the Three Plan Retained for Further Analysis 

Plan 2 

Acres 

Created 

Acres 

Nourished Total Acres Net Acres AAHUs Borrow Volume

Floatation 

Footprint 

Dispos

Footpri

Golden Triangle Wetland Creation (WC) 1,500 ac 1,350 ac 2,850 ac 1,685 ac 1,094 9,500,000 2.8 ac 4.1 ac  Length Erosion Rate Total protected Net Acres AAHUs Tons of Rock Golden Triangle Shoreline Protection (SP) 17,700 11 ft/yr 223 ac 115 ac 34 125,000 40.6 ac 29.0 aB. Bienvenue Vicinity SP (Reach A) 16,230 10 ft/yr 186 ac 96 ac 28 121,200 33.8 ac 21.5 aB. Dupre Vicinity SP (Reach B) 17,650 7 ft/yr 142 ac 73 ac 21 137,000 38.0 ac 20.7 aWest of Shell Beach SP (Reach C) 15,400 11 ft/yr 194 ac 101 ac 28 165,000 15.0 ac 24.0 aMRGO ACM (South Shore) 10,840 24.2 ft/yr 301 ac 194 ac 73 24,600 56.0 ac 62.7 a

Totals: 77,820 3,896 ac 2,264 ac 1,278 572,800 186.2 ac 162.0 a

Plan 3 

Acres 

Created 

Acres 

Nourished Total Acres Net Acres AAHUs Borrow Volume

Floatation 

Footprint 

Dispos

Footpri

Golden Triangle WC 1,400 ac 1,350 ac 2,750 ac 1,608 ac 1,038 7,400,000 2.8 ac 4.1 ac Shell Beach WC 500 ac 420 ac 920 ac 479 ac 329 4,000,000 8.3 ac 12.4 a

Total Wetland Creation: 1,900 1,770 3,670 ac 2,087 ac 1,367 11,400,000 

 Length Erosion Rate Total protected Net Acres AAHUs Tons of Rock B. Bienvenue Vicinity SP (Reach A) 16,230 10 ft/yr 186 ac 96 ac 28 121,200 33.8 ac 21.5 aWest of Shell Beach SP (Reach C) 15,400 11 ft/yr 194 ac 101 ac 28 165,000 15.0 ac 24.0 a

Totals: 31,630 4,050 ac 2,284 ac 1,423 286,200 59.9 ac 62.0 a

Plan 10 

Acres 

Created 

Acres 

Nourished Total Acres Net Acres AAHUs Borrow Volume

Floatation 

Footprint 

Dispos

Footpri

Golden Triangle WC 1,250 ac 1,400 ac 2,650 ac 1,495 ac 856 6,500,000 2.8 ac 4.1 ac Shell Beach WC 425 ac 270 ac 695 ac 397 ac 256 3,200,000 8.3 ac 12.4 a

Total Wetland Creation: 1,675 1,670 3,345 ac 1,892 ac 1,112 9,700,000 

 Length (ft) Erosion Rate Total protected Net Acres AAHUs Tons of Rock B. Bienvenue Vicinity SP (Reach A) 16,230 10 ft/yr 186 ac 96 ac 28 121,200 33.8 ac 21.5 aB. Dupre Vicinity SP (Reach B) 17,650 7 ft/yr 142 ac 73 ac 21 137,000 38.0 ac 20.7 aWest of Shell Beach SP (Reach C) 15,400 11 ft/yr 194 ac 101 ac 28 165,000 35.4 ac 24.0 a

Totals: 49,280 3,867 ac 2,162 ac 1,189 423,200 118.3 ac 82.7 a
Chapter 2 Alternatives 

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 2 – 26

2.4.4.2 Plan 3 Summary 

Plan 3 would create 1,400 acres (567 ha) and nourish 1,350 acres (547 ha) of brackish marsh in 

the Golden Triangle; and create 500 acres (203 ha) and nourish 420 acres (170 ha) of saline 

marsh in the area west of Shell Beach (Figure 2.2). Plan 3 would also construct two shoreline 

protection features located along the Lake Borgne shoreline in the vicinity of Bayou Bienvenue 

(16,230 lf; 4,946 m) to protect 186 acres (75 ha) and west of Shell Beach (15,400 lf; 4,694 m) to 

protect 194 acres (79 ha). These shoreline protection features would protect a total of 380 acres 

(154 ha) of adjacent fragmented wetlands from degradation and wave erosion. Plan 3 would 

require a total 11.4 million cy (8.7 million cubic meters) of borrow for wetland creation and 

nourishment that would be removed from approximately 1,850 acres (750 ha) of Lake Borgne 

water bottoms (Figure 2.2). Plan 3 would place a total of 134,000 square yards (112,167 sq m) 

of geotextile fabric and 286,200 tons (282,667 metric tons) of crushed rock along the Lake 

Borgne shoreline. A total of 59.9 acres (24.3 ha) of Lake Borgne water bottoms would be 

dredged for floatation access. Material dredged for floatation access would be used beneficially 

to the maximum extent practicable to create wetlands between the shoreline protection dike and 

the shoreline, or temporarily stockpiled adjacent to the floatation channel in open water and 

returned to the channel following completion of construction features. 

2.4.4.3 Plan 10 Summary 

Plan 10 would create 1,250 acres (506 ha) and nourish 1,400 acres (567 ha) of brackish marsh in 

the Golden Triangle; and create 425 acres (172 ha) and nourish 270 acres (109 ha) of saline 

marsh west of Shell Beach (Figure 2.3). Plan 10 also includes three shoreline protection 

features located along the Lake Borgne shoreline: in the vicinity of Bayou Bienvenue (16,230 lf; 

4,946 m) to protect 186 acres (75 ha); in the vicinity of Bayou Dupre (17,650 lf; 5,379 m) to 

protect 142 acres (58 ha); and west of Shell Beach (15,400 lf; 4,694 m) to protect 194 acres 

(79 ha). These shoreline protection features would protect a total of 522 acres (211 ha) of 

adjacent wetlands from degradation and wave erosion. Plan 10 would require a total of 

9.7 million cy (7.4 million cubic meters) of borrow for wetland creation and nourishment that 

would be removed from approximately 1,850 acres (750 ha) of Lake Borgne water bottoms 

(Figure 2.3). Plan 10 would place a total of 208,650 square yards (174,654 sq m) of geotextile 

fabric and 423,200 tons (417,975 metric tons) of rock along the Lake Borgne shoreline. 

A total of 118.3 acres (47.9 ha) of Lake Borgne water bottoms would be dredged for floatation 

access. Material dredged for floatation access would be used beneficially to the maximum 

extent practicable to create wetlands between the shoreline protection dike and the shoreline, or 

temporarily stockpiled adjacent to the floatation channel in open water and returned to the 

channel following completion of construction features. 
Chapter 2 

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Figure 2.1 Plan 2 Features 
Chapter 2 

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Figure 2.2 Plan 3 Features 
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Figure 2.3 Plan 10 Features
Chapter 2 Alternatives 

FEIS June 2009 

 2 – 30

2.5 NO-ACTION ALTERNATIVE 

The No-Action Alternative assumes there would be no wetland creation or shoreline protection 

features constructed within the project area beyond existing projects or those projects presently 

authorized for construction or maintenance actions (e.g., CWPPRA PO-30 and PO-32, the 

MRGO North Bank Shoreline Protection project from Mile 40 to 44.5, the Greater New Orleans 

Hurricane and Storm Damage Risk Reduction System structure, and the MRGO closure 

structure near Bayou La Loutre). The remainder of the critical land bridge between Lake 

Borgne and the MRGO would not be protected or restored and would continue to be subjected 

to natural and human land-loss factors such as tropical storms, subsidence, wind-driven 

shoreline erosion of Lake Borgne, sea level change, deep-draft navigation vessel-induced 

erosion of the MRGO, oil and gas exploration, and saltwater intrusion. Recent analysis 

(personal communication, Van Stutts, LACPR Hydrology Team, 2007) indicates that tropical 

storm intensity, storm surge, and flood stages will likely continue to increase throughout 

southeastern Louisiana. Consequently, wetland loss throughout the project area would continue 

at the same or accelerated rates. About 6,255 acres (2,534 ha) of brackish marsh and 

3,595 acres (1,454 ha) of saline marsh are projected to be lost in the project area over the 50-

year period of analysis, for a total loss of 9,850 acres (3,991 ha) of emergent wetlands (Barras, 

2006). All of these factors would contribute to the continued degradation of the land bridge 

between Lake Borgne and the MRGO. 

Continued wetland fragmentation and the eventual conversion to shallow open water habitat 

would have negative consequences on a variety of important environmental resources in the 

project area. This is the future scenario to which the alternatives considered in detail are 

compared. 

The project area would be converted from an emergent wetland-dominated estuarine-marine 

system to a primarily open water estuarine-marine system. Continued habitat degradation and 

eventual loss of 9,850 acres (3,991 ha) in the project area would result in the loss of important 

and essential fish and wildlife habitats used for shelter, nesting, feeding, roosting, cover, 

nursery, and other life requirements; reduction in productivity; degradation and loss of essential 

fish habitat (EFH), especially marsh-edge habitat and transitional habitat between estuarine and 

marine environments; and increased inter- and intra-specific competition between resident and 

migratory fish and wildlife species for decreasing coastal wetland resources. No threatened or 

endangered species would be directly impacted by the habitat degradation and eventual loss. 

However, species that are linked in the food chain would be indirectly affected; population 

reductions and shifts in predator/prey relationships would lead to localized decline in fishery 

productivity and reduced recreational opportunities for fishing, hunting or wildlife observation. 

Impacts to fish populations would result from the continued loss and/or degradation of EFH, 

shoreline erosion, subsidence, and overall wetland loss. 

Impacts from salt-water intrusion have already occurred. Trends toward a predominantly 

marine fish population and large increases in salinity in the project area were identified by 

Fontenot and Rogillo (1970) during the early 1960s. Since that time, little has taken place in the 

project area to slow down or prevent saltwater intrusion into the wetlands and waterways 

surrounding the MRGO. Therefore, impacts from salt-water intrusion on local fish, plankton, 

and benthic resources in the project area have already occurred and are past the point of 

prevention. 
Chapter 2 Alternatives 

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The Integrated Final Report to Congress and Legislative Environmental Impact Statement for 

the MRGO Deep-Draft Deauthorization Study provide comprehensive documentation of the 

direct, indirect, and cumulative environmental effects attributable to alternative plans for the deauthorization of navigation on the MRGO between the GIWW and the Gulf of Mexico. The 

Recommended Plan for this study is to construct a total closure structure across the MRGO near 

Bayou La Loutre in one construction effort. The final report was delivered to Congress on June 

5, 2008. Construction of the closure structure is anticipated to be completed before the 

beginning of the 2009 hurricane season. This structure is anticipated to reduce salinities in the 

project area by up to 6.6 ppt (USACE, 2007). This could decrease the trend towards more salttolerant plant species in the wetlands after construction is completed, and increase the area of 

brackish marsh relative to saline marsh. 

Additionally, the Greater New Orleans Hurricane and Storm Damage Risk Reduction System 

structure would include sector gates across the GIWW and Bayou Bienvenue near the western 

end of the Golden Triangle, as well as a closure structure (concrete floodwall) across the 

MRGO channel south of its intersection with Bayou Bienvenue. According to IER #11 for this 

project, “although this alternative includes a closure of the MRGO channel near Bayou 

Bienvenue, the proposed action is not expected to have a significant change in existing salinity 

regimes within the project area.” Nevertheless, the proposed floodwall could increase the 

duration of wetted time for nearby wetlands by up to seven hours per day, and the average water 

level by 0.1 ft (0.03 m) (USACE, 2008). 

Under the No-Action Alternative, hydrology resources would be impacted by the extensive land 

loss resulting in unrestricted flow patterns. Sediment supply into the area would continue to 

decrease. The project area would continue not to be used for groundwater extraction or for 

other water uses and supply. Water quality would remain similar to existing conditions. 

The project area is remote and uninhabited by man. There are no infrastructure, employment 

and income, agriculture, or forestry resources within the project area. Although not occurring 

within the project area, there are flood control and hurricane protection levees immediately to 

the north and west of the project area. Aesthetically, viewscapes of existing fragmented 

wetlands and open water would change to viewscapes of wide expanses of open waters. The 

continued loss of wetlands in the project area would continue to threaten the integrity of any 

existing cultural resources; reduce recreational opportunities and commercial fishery success; 

and may contribute to greater costs to maintain oil and gas pipelines (See Table 2.7 for a 

summary of impacts to important resources). Institutional regulation of air quality would 

continue; however, increased human populations and industries in southeastern Louisiana and 

nation-wide would likely result in decreased air quality. 

2.6 PLAN FORMULATION RESULTS 

Plans 2 and 3 would provide a net benefit of 2,264 acres (917 ha) and 2,284 acres (925 ha) over 

the project life, respectively, whereas Plan 10 would provide a net benefit of 2,162 acres 

(876 ha). This would be 122 acres (49 ha) less than Plan 3, and 102 acres (41 ha) less than 

Plan 2. Plans 2 and 3 were projected to have greater value than Plan 10 (1,278 AAHU and 

1,423 AAHU, respectively, versus 1,189 AAHU), but Plan 10 more completely provides 

protection to the critical land bridge with more shoreline protection features. 
Chapter 2 Alternatives 

FEIS June 2009 

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2.6.1 Description of the Selected Plan (SP) 

Comparison of the three alternative plans carried over for detailed analysis and the NoAction Alternative, identified Plan 10 as the plan that best met the screening criteria and would 

best accomplish the planning objectives and goals. Hence, Plan 10 is the Selected Plan (SP). 

The SP features would be consistent with Congressional direction authorized by Chapter 3, 

under division B, of title I of Public Law 109-148 (119 Stat. 2762) under the heading 

“Operations and Maintenance,” as amended by Section 2304 of Public Law 109-234 (120 Stat. 

418). The SP would also be consistent with the Environmental Operating Principles. The SP 

would create a total of 1,675 acres (679 ha) of marsh and nourish an additional 1,670 acres 

(677 ha) of emergent wetlands in the Golden Triangle and Shell Beach vicinities. The SP would 

also provide shoreline protection in the form of foreshore rock dikes along three reaches of the 

Lake Borgne. Shoreline protection features would protect a total of 522 acres (211 ha) of 

adjacent wetlands from degradation and wave erosion. Over the 50-year period of analysis, the 

SP would create, nourish and protect a net total of 2,162 acres (876 ha). Table 2.8 summarizes 

SP features. 
Chapter 2 

FEIS 

2 – 33

Table 2.7 Comparison of Opportunities in the Project area to the No-Action Alternative 

Among Significant Resources as well as Noise and HTRW 

Significant Resource No-Action Alternative Alternative Plan 10 (SP) Alternative Plan 2 ASoils 

Projected loss of 9,850 acres of wetland soils (primarily Clovelly muck and Lafayette muck soils). 

A total of 1,850 acres of Lake Borgne water bottoms would be used as borrow for wetland creation. A net total of 2,162 acres of wetland soils would be created, nourished and protected. Placement of rock shoreline protection features would compact about 64.3 acres of soils along Lake Borgne water bottoms and MRGO bankline. 

Impacts similar to Alternative 10 (SP), a total of 1,070 acres of Lake Borgne water bottoms would be used as borrow for wetland creation, with a net total of 2,264 acres of wetland soils created, nourished and protected. Placement of rock shoreline protection features would compact about 123.8 acres of soils along Lake Borgne water bottoms and MRGO bankline. 

IAw2saPsfasB

Coastal Vegetation 

Long-term net decrease in emergent wetland vegetation by 9,850 acres. Possible shift of some saline marshes to brackish marshes with the construction of a closure structure on the MRGO channel. 

A net total of 2,162 acres of emergent wetlands created, nourished and protected. Increased acreages of emergent vegetation would act as natural filters for pollutants and contaminants in the project area. 

Impacts similar to Alternative 10 (SP), with a net total of 2,264 acres of emergent wetlands created, nourished and protected. 

IAw2wnp
Chapter 2 

FEIS 

2 – 34

Significant Resource No-Action Alternative Alternative Plan 10 (SP) Alternative Plan 2 AWildlife 

Continued decline in wildlife habitat due to conversion of 9,850 acres of emergent wetlands to open water habitat. 

Increase in potential wildlife habitat by a net total of 2,162 acres of emergent wetlands. 

Increase in potential wildlife habitat by a net total of 2,264 acres of emergent wetlands protected. 

Iwtoe

Fishery 

Loss of 9,850 acres of transitional fishery habitat between estuarine and marine environments used for nursery, foraging and other life requirements. 

Increase in potential transitional habitat by a net total of 2,162 acres of emergent wetlands. 

Increase in potential transitional habitat by a net total of 2,264 acres of emergent wetlands protected. 

Itrno

Plankton 

Saline-dominant plankton community would not change from existing conditions. 

Temporary and localized impacts (e.g., decreased dissolved oxygen, increased turbidity) to plankton community during construction activities. 

Impacts similar to Alternative 10 (SP). 

IA

Water bottoms and Benthic 

Water bottoms and benthic community would not change from existing conditions. 

A total of 1,850 acres of Lake Borgne water bottoms would be used as borrow for wetland creation. Unavoidable direct loss of benthos due to construction & dredging activities. However, increase in emergent wetlands by a net total of 2,162 acres provides greater heterogeneity and interspersion of habitat types. 

Impacts would be similar to Alternative 10 (SP). However, increase in emergent wetlands by a net total of 2,264 acres provides greater heterogeneity and interspersion of habitat types. 

IsAHenphinty
Chapter 2 

FEIS 

2 – 35

Significant Resource No-Action Alternative Alternative Plan 10 (SP) Alternative Plan 2 AEssential Fish Habitat 

The conversion of 9,850 acres of marsh, a more productive category of EFH to water bottoms, a less productive category. 

Conversion of a net total of 2,162 acres of water bottoms, a less productive and increasingly common category of EFH to marsh, a more productive category of EFH. Conversion of up to 1,850 acres of shallow estuarine benthic habitat to deep-water benthic habitat. 

Impacts would be similar to Alternative 10 (SP), but would convert a net total of 2,264 acres of EFH to a more productive category. Conversion of up to 1,070 acres of shallow estuarine benthic habitat to deep-water benthic habitat. 

IsAwtoEpC1ehb

Threatened & Endangered Species 

Continued Federal management of endangered species and its critical habitat. 

Although proposed action would involve activities in the critical habitat of the Gulf sturgeon, the scope of activities constitute a Not Likely to Adversely Affect determination. 

Impacts similar to Alternative 10 (SP). 

IA
Chapter 2 

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Significant Resource No-Action Alternative Alternative Plan 10 (SP) Alternative Plan 2 AHydrology – Flow and Water Levels 

Conversion of 9,850 acres of existing emergent wetlands to open water would decrease roughness factor thereby altering existing flows within the area. The floodwall proposed by IER #11 could increase mean water levels by 0.1 ft (0.03 m). 

Shoreline protection features would impact flow between Lake Borgne and the shoreline and the MRGO and its banks, as well as to adjacent emergent wetlands. Natural channels would not be impacted. 

Impacts similar to Alternative 10 (SP). 

IA

Hydrology - Sediment 

Existing processes of sediment imported into system primarily by resuspension would continue; sediment supply will continue not to offset land loss. 

About 9.7 million cy of borrow material from Lake Borgne water bottoms converted to emergent wetland-type soils. 

About 9.5 million cy of borrow material from Lake Borgne water bottoms converted to emergent wetlandtype soils. 

Aofwcw

Water Quality 

Continued discharge of untreated storm runoff and sewerage from populated areas in the upper portions of the Lake Pontchartrain basin and into project area. Average salinities may decline with the proposed construction of a closure structure on the MRGO channel. 

Creation, nourishment and protection of a net total of 2,162 acres of emergent wetlands act as natural filter for pollutants and improve the overall water quality within the project area. 

Impacts similar to Alternative 10 (SP). 

IA

Recreational Resources 

Potential loss of recreational resource base, especially recreational fishing and hunting, due to loss of 9,850 acres of emergent wetlands. 

The proposed action would support and sustain a higher number of brackish and saline marsh recreational opportunities. 

Impacts would be similar to Alternative 10 (SP) except that no saline marsh would be created and nourished. 

IsA
Chapter 2 

FEIS 

2 – 37

Significant Resource No-Action Alternative Alternative Plan 10 (SP) Alternative Plan 2 APublic Lands 

Potential loss of opportunities due to continued coastal and wetland degradation and loss. 

The proposed action would increase the acreage of wetlands on and near public lands, and increase the sustainability and functionality of this resource. 

Impacts would be similar to Alternative 10 (SP). 

IsA

Cultural Resources 

Loss of 9,850 acres over 50-year period of analysis and coalescence of MRGO and Lake Borgne threatens the existence and integrity of cultural resources in the project area. 

Requires project specific cultural resources investigation; however, in the long-term, arresting land loss would protect cultural resources from erosion. 

Impacts similar to Alternative 10 (SP). 

IA

Aesthetics 

Loss of 9,850 acres over 50-year period of analysis and coalescence of MRGO and Lake Borgne reduces visual complexity and desirable viewscapes including those scenic streams and rivers in the project area. 

Creation, nourishment and protection of a net total of 2,162 acres of emergent wetlands enhance and protect desirable viewscapes, including those scenic streams and rivers in the project area. 

Impacts similar to Alternative 10 (SP). 

IA

Noise 

Continued human activities within the project area may have some noise. 

Localized and temporary increased noise typically associated with actual construction activities. All legal requirements for noise abatement would be followed. 

Impacts similar to Alternative 10 (SP). 

IA

Air Quality 

Air quality would likely continue to decline as populations and industrialization increases in nearby areas. 

Created, nourished and protected wetlands act as natural filters for air pollutants. 

Impacts would be similar to Alternative 10 (SP). 

IsA
Chapter 2 

FEIS 

2 – 38

Significant Resource No-Action Alternative Alternative Plan 10 (SP) Alternative Plan 2 ASocioeconomic and Human Resources – Population 

Project area is remote and uninhabited. 

Impacts similar to the No-Action Alternative. 

Impacts similar to the No-Action Alternative. 

IN

Socioeconomic and Human Resources – Infrastructure 

Utilities pipelines are located within the project area. Continued emergent wetland loss would be expected, which would affect relocations and maintenance of utilities within the project area. 

There would be a reduced level of infrastructure damages and relocations than with the NoAction. 

Impacts would be similar to Alternative 10 (SP). 

IA

Socioeconomic and Human Resources – Employment and Income 

Project area is remote and uninhabited and is not expected to change. 

Impacts similar to the No-Action Alternative. 

Impacts similar to the No-Action Alternative. 

IN

Socioeconomic and Human Resources – Navigation 

Loss of 9,850 acres over 50-year period of analysis and coalescence of MRGO and Lake Borgne. MRGO closed to navigation (WRDA of 2007). 

Would prevent coalescence of the MRGO and Lake Borgne; no effect on navigation in the MRGO; provide some protection to navigation in the GIWW. 

Impacts similar to Alternative 10 (SP). 

IA

Socioeconomic and Human Resources – Oil, Gas, and Utilities Pipelines 

Relocations and re-burying of pipelines due to the loss of 9,850 acres and coalescence of Lake Borgne and MRGO. 

Proposed actions would reduce emergent wetlands erosion, so relocations and maintenance may be reduced. 

Impacts would be similar to Alternative 10 (SP). 

IsA
Chapter 2 

FEIS 

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Significant Resource No-Action Alternative Alternative Plan 10 (SP) Alternative Plan 2 ASocioeconomic and Human Resources – Commercial Fisheries 

Loss in production would be expected as quality habitat continues eroding interior emergent wetlands. 

Proposed action would increase habitat quality within the area. This would benefit commercial fisheries by providing a suitable habitat for fishery dependent resources within project area. 

Impacts would be similar to Alternative 10 (SP). 

IsA

Socioeconomic and Human Resources – Oyster Leases 

Local production of oyster leases likely to decline with loss of 9,850 acres of emergent wetlands and coalescence of Lake Borgne and MRGO. 

A small percent of oyster leases are within the project area. Leases would be acquired by the local sponsor and owners would be compensated accordingly. 

Impacts would be similar to Alternative 10 (SP). 

IsA

Socioeconomic and Human Resources – Flood Control and Hurricane Protection Levees 

There are no flood control or hurricane protection levees within the project area. A proposed floodwall would be located in the northwest corner of the Golden Triangle. Existing and proposed flood control and hurricane protection levees near the project area would become more exposed over time. 

Impacts would be similar to the No-Action Alternative, except that project features would indirectly protect the existing and proposed flood control and hurricane protection levees to a greater extent. 

Impacts would be similar to Alternative 10 (SP). 

IsA

HTRW 

Increasing human populations, development, industry, and other activities in adjacent areas could further increase potential for HTRW within the project area. 

An HTRW Phase I ESA was performed on the project area, and identified a low probability of encountering contaminants of concern. 

An HTRW Phase I ESA was performed on the project area, and identified a low probability of encountering contaminants of concern. 

AEthidpecc
Chapter 2 Alternatives 

FEIS June 2009 

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Table 2.8 Summary of Selected Plan Features 

Plan 10 (SP) Features 

Acres 

Created 

Acres 

Nourished Total Acres Net Acres AAHUs 

Golden Triangle Wetland Creation (WC) 1,250 ac 1,400 ac 2,650 ac 1,495 ac 856 

Shell Beach WC 425 ac 270 ac 695 ac 397 ac 256 

Total Wetland Creation: 1,675 1,670 3,345 ac 1,892 ac 1,112 

 Length (ft) Erosion Rate Total protected Net Acres AAHUs 

B. Bienvenue Vicinity Shoreline 

Protection (SP) (Reach A) 16,230 10 ft/yr 186 ac 96 ac 28 

B. Dupre Vicinity SP (Reach B) 17,650 7 ft/yr 142 ac 73 ac 21 

West of Shell Beach SP (Reach C) 15,400 11 ft/yr 194 ac 101 ac 28 

Totals: 49,280 3,867 ac 2,162 ac 1,189 

2.6.1.1 Components of the Selected Plan 

The SP would create 1,250 acres (506 ha) and nourish 1,400 acres (567 ha) of brackish marsh in 

the Golden Triangle as well as create 425 acres (172 ha) and nourish 270 acres (109 ha) of 

saline marsh west of Shell Beach (Figure 2.3). The SP would construct three shoreline 

protection features along the Lake Borgne shoreline: in the vicinity of Bayou Bienvenue 

(16,230 lf; 4,946 m); in the vicinity of Bayou Dupre (17,650 lf; 5,379 m); and west of Shell 

Beach (15,400 lf; 4,694 m). Shoreline protection features would protect a total of 522 acres 

(211 ha) of adjacent fragmented wetlands along Lake Borgne from degradation and wave 

erosion. 

A total of 9,700,000 cy (7,406,454 cubic meters) of borrow material would be removed from 

approximately 1,850 acres (750 ha) of Lake Borgne water bottoms for wetland creation and 

nourishment (Figure 2.3). Additionally, a total of about 11.1 acres (4.5 ha) would be dredged 

for floatation access, with material stockpiled on about 16.5 acres (6.7 ha) of Lake Borgne water 

bottom, until after construction, when that material would be backfilled. Shoreline protection 

features in Lake Borgne would require a total of 208,650 sq yd (174,653 sq m) of geotextile 

fabric and 423,200 tons (417,975 metric tons) of rock. 

Shoreline protection features (foreshore rock dikes) would cover 39.5 acres (16.0 ha) of Lake 

Borgne water bottoms. A total of 107.3 acres (43.5 ha) of Lake Borgne water bottoms would be 

dredged for floatation access for shoreline protection features. Material dredged for floatation 

access would be placed on a total of 66.2 acres (26.8 ha) of Lake Borgne water bottoms. 

Material dredged for floatation access would be used beneficially, to the maximum extent 

practicable, to create wetlands between the shoreline protection features and the shoreline, or 

would be temporarily stockpiled adjacent to the floatation channel in open water and returned to 

the channel following completion of construction. 

2.6.1.1.1 Golden Triangle Wetland Creation and Nourishment 

Approximately 6,500,000 cy (4,963,088 cubic meters) of borrow material hydraulically dredged 

from Lake Borgne water bottoms would create 1,250 acres (506 ha) of brackish marsh 

(Figure 2.4). Retention dikes and closures would be constructed using a bucket or clamshell 

dredge to contain the dredged slurry to a fill height of +3.2 ft (1.0 m) NAVD88. After 
Chapter 2 Alternatives 

FEIS June 2009 

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dewatering and initial consolidation (about one year), the target elevation of +0.5 to +1.5 ft 

(+0.2 to +0.5 m) NAVD88 would be attained. Dredged slurry would also be used to nourish 

about 1,400 acres (567 ha) of brackish marsh. In order to insure intertidal exchange into the 

marsh creation areas, if the retention dikes have not naturally degraded within about one year 

following consolidation of the borrow material, the retention dikes would be degraded as 

necessary subject to available authority and funding. Vegetation would naturally re-colonize 

the wetland creation site within about one year. These activities would result in a net benefit of 

1,495 acres (606 ha) compared to the No-Action alternative, with a net value of 856 AAHUs. 

An area of approximately 1,070 acres (433 ha) without existing oyster leases was identified in 

the western lobe of Lake Borgne at least 3,000 ft (914 m) from the shoreline. The water 

bottoms of this area would be dredged to a maximum of 20 ft (6.1 m) below the existing water 

bottom to supply the borrow material for construction of this feature. A total of 2.8 acres 

(0.85 ha) would be dredged to create a floatation channel to allow construction equipment to 

access the borrow site and install conveyance pipelines. Material dredged for floatation access 

would be stockpiled adjacent to the floatation channel in open water over 4.1 acres (1.7 ha). 

The floatation access channel would be back-filled following construction. 

2.6.1.1.2 Shell Beach Wetland Creation and Nourishment 

Approximately 3,200,000 cy (2,443,366 cubic meters) of borrow material hydraulically dredged 

from Lake Borgne water bottoms would create 425 acres (172 ha) of saline marsh at five sites 

near Shell Beach (Figure 2.5). Retention dikes and closures would be constructed using a 

bucket or clamshell dredge to contain the dredged slurry to a fill height of +3.2 ft (1.0 m) 

NAVD88. After dewatering and initial consolidation, the target elevation of +0.5 to +1.5 ft 

(+0.2 to +0.5 m) NAVD88 would be attained. Dredge slurry would also be used to nourish 

about 270 acres (109 ha) of saline marsh. In order to insure intertidal exchange into the marsh 

creation areas, if the retention dikes have not naturally degraded within about one year 

following consolidation of the borrow material, the retention dikes would be degraded as 

necessary subject to available authority and funding. Vegetation would naturally re-colonize 

the wetland creation site within about one year. These activities would result in a net benefit of 

397 acres (161 ha) compared to the No-Action alternative, with a net value of 256 AAHUs. 

A total of 780 acres (316 ha) without existing oyster leases was identified in three locations in 

the eastern lobe of Lake Borgne at least 3,000 ft (914 m) from the shoreline. The westernmost 

two sites each encompass 230 acres (70 ha), and the easternmost site encompasses 320 acres 

(98 ha). These water bottoms would be dredged to 20 ft (6.1 m) below the existing water 

bottom to supply the borrow material for construction of this feature. A total of 8.3 acres 

(3.4 ha) would be dredged to create floatation channels to allow construction equipment to 

access the borrow site and install conveyance pipelines. Material dredged for floatation access 

would be stockpiled adjacent to the floatation channel in open water over 12.4 acres (5.0 ha) of 

Lake Borgne water bottoms. The floatation access channel would be back-filled following 

construction. The westernmost wetland creation cell would require closure of a 950-foot 

(290 m) breach along the Lake Borgne shoreline. Construction of a sheetpile, rock, or earthen 

dike would be used to contain the dredged slurry. 
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Figure 2.4 Features of the SP (Western Features) 
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Figure 2.5 Features of the SP (Eastern Features)
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2.6.1.1.3 Shoreline Protection in the Vicinity of Bayou Bienvenue 

This SP feature would control shoreline erosion of brackish marshes from Bayou Bienvenue to 

the western end of the authorized-for-construction CWPPRA PO-30 project (Figure 2.4). A 

16,230 linear foot-long (4,947 m) rock dike would be constructed along the -1.5 to -2.0-foot 

(-0.5 to -0.6 m) NAVD88 contour approximately 150 ft (46 m) from the existing shoreline 

(Figure 2.6). Approximately 121,200 tons (119,704 metric tons) of rock and 65,000 sq yd 

(54,409 sq m) of geotextile fabric would be placed over 11.2 acres (4.5 ha) of Lake Borgne 

water bottoms. The specific location of the rock dike would be dependent on the bathymetry 

and any cultural resources sites that may need to be avoided. The rock dike would be 

constructed to an elevation of +4.0 ft (1.2 m) NAVD88, with 1V on 2H side slopes, and a fourfoot (1.2 m) crown width. Fish dips (Figure 2.7) would be incorporated into the foreshore dikes 

to allow access for aquatic organisms to shallow open water and marsh along the shoreline, and 

other areas that are frequently inundated by tides. This SP feature would protect 186 acres 

(75 ha) of fragmented wetlands, resulting in a net benefit of 96 acres (39 ha) of brackish marsh 

and 28 AAHU over the 50-year period of analysis. 

A floatation channel no wider than 80 ft (24.4 m) bottom width would parallel the dike 

alignment to allow construction access of the construction equipment. Approximately 

33.8 acres (13.7 ha) would be dredged to a depth of –seven ft (-2.1 m) NAVD88 via bucket or 

clamshell dredge for this channel. This material would be used beneficially between the dike 

and the shoreline to create wetlands to the maximum extent practicable. Material would be 

placed in a 50-foot (15.2 m) wide footprint no closer than ten ft (3.0 m) from the inside of the 

rock dike and no closer than 50 ft (15.2 m) from the existing shoreline to a maximum elevation 

of +4.2 ft (+1.3 m) NAVD88 so that the final elevation would be lower than the dike. 

Approximately 21.5 acres (8.7 ha) of shallow water bottom would be covered by this placed 

material. Excess material would be stockpiled adjacent to the channel in open water and 

returned to the floatation channel at the end of construction. Access channels located about 

one-mile (1.6 km) apart and running perpendicular to the shoreline would allow equipment to 

reach the floatation channel. Floatation access channels would have a maximum bottom width 

of 80 ft (24.4 m) and material would be stockpiled adjacent to the channel and returned to it at 

the end of construction. Acreage impacts for this access are included in the floatation access 

acreage. 

2.6.1.1.4 Shoreline Protection in the Vicinity of Bayou Dupre 

This shoreline protection feature would control shoreline erosion of brackish marshes in the 

vicinity of Bayou Dupre (Figure 2.4). A rock dike 17,650 ft (5,379 m) long would be 

constructed approximately 150 ft (46 m) from the existing shoreline along the -1.5 to -2.0 foot (-

0.5 to -0.6 m) NAVD88 contour (Figure 2.6). Approximately 137,000 tons (135,309 metric 

tons) of rock and 74,650 sq yd (62,487 sq m) of geotextile fabric would be placed over 

12.3 acres (5.0 ha) of Lake Borgne water bottoms. The specific location of the rock dike would 

be dependent on the bathymetry and any cultural resources sites that may need to be avoided. 

The rock dike would be constructed to an elevation of +4.0 ft (1.2 m) NAVD88, with 1V on 2H 

side slopes, and a 4-foot (1.2 m) crown width. Fish dips (figure 2.7) would be incorporated into 

the foreshore dikes to allow access for aquatic organisms to shallow open water and marsh 

along the shoreline, and other areas that are frequently inundated by tides. This SP feature 
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Figure 2.6 Typical Dike Cross Section for Lake Borgne Shoreline Protection Features 
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Figure 2.7 Typical Fish Dip Design 
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would protect 142 acres (58 ha) of fragmented wetlands, resulting in a net benefit of 73 acres 

(30 ha) of brackish marsh and 21 AAHU over the 50-year period of analysis. 

A floatation channel no wider than 80 ft (24.4 m) bottom width would parallel the dike 

alignment to allow construction access of the construction equipment. Approximately 

38.0 acres (15.4 ha) would be dredged to a depth of –seven ft (-2.1 m) NAVD88 via bucket or 

clamshell dredge for this channel. This material would be used beneficially between the dike 

and the shoreline to create wetlands to the maximum extent practicable. Material would be 

placed in a 50-foot (15.2 m) wide footprint no closer than ten ft (3.0 m) from the inside of the 

rock dike and no closer than 50 ft (15.2 m) from the existing shoreline to a maximum elevation 

of +4.2 ft (+1.3 m) NAVD88 so that the final elevation would be lower than the dike. 

Approximately 20.7 acres (8.4 ha) of shallow water bottom would be covered by this placed 

material. Excess material would be stockpiled adjacent to the channel in open water and 

returned to the floatation channel at the end of construction. Access channels located about 

one mile (1.6 km) apart and running perpendicular to the shoreline would allow equipment to 

reach the floatation channel. Floatation access channels would have a maximum bottom width 

of 80 ft (24.4 m) and material would be stockpiled adjacent to the channel and returned to it at 

the end of construction. Acreage impacts for this access are included in the floatation access 

acreage. 

2.6.1.1.5 Shoreline Protection West of Shell Beach 

This shoreline protection feature would control erosion of saline marshes along the Lake Borgne 

shoreline west of Shell Beach (Figure 2.5). A 15,400 lf (4,694 m) rock dike would be 

constructed along the -1.5 to -2.0-foot (-0.5 to -0.6 m) NAVD88 contour approximately 150 ft 

(46 m) from the existing shoreline (Figure 2.6). Approximately 165,000 tons (162,963 metric 

tons) of rock and 69,000 sq yd (57,758 sq m) of geotextile fabric would be placed over 

16.0 acres (6.5 ha) of Lake Borgne water bottoms. The specific location of the rock dike would 

be dependent on the bathymetry and any cultural resources sites that may need to be avoided. 

The rock dike would be constructed to an elevation of +4.0 ft (1.2 m) NAVD88, with 1V on 2H 

side slopes, and a 4-foot (1.2 m) crown width. Fish dips (Figure 2.7) would be incorporated 

into the foreshore dikes to allow access for aquatic organisms to shallow open water and marsh 

along the shoreline, and other areas that are frequently inundated by tides. This SP feature 

would protect 194 acres (79 ha) of fragmented wetlands, resulting in a net benefit of 101 acres 

(41 ha) of saline marsh and 28 AAHU over the 50-year period of analysis. 

A floatation channel no wider than 80 ft (24.4 m) bottom width would parallel the dike 

alignment to allow construction access of the construction equipment. Approximately 

35.4 acres (14.3 ha) would be dredged to a depth of –seven ft (-2.1 m) NAVD88 via bucket or 

clamshell dredge for this channel. This material would be used beneficially between the dike 

and the shoreline to create wetlands to the maximum extent practicable. Material would be 

placed in a 50-foot (15.2 m) wide footprint no closer than ten ft (3.0 m) from the inside of the 

rock dike and no closer than 50 ft (15.2 m) from the existing shoreline to a maximum elevation 

of +4.2 ft (+1.3 m) NAVD88 so that the final elevation would be lower than the dike. 

Approximately 24.0 acres (9.7 ha) of shallow water bottom would be covered by this placed 

material. Excess material would be stockpiled adjacent to the channel in open water and 

returned to the floatation channel at the end of construction. Access channels located about 

one mile (1.6 km) apart and running perpendicular to the shoreline would allow equipment to 
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reach the floatation channel. Floatation access channels would have a maximum bottom width 

of 80 ft (24.4 m) and material would be stockpiled adjacent to the channel and returned to it at 

the end of construction. Acreage impacts for this access are included in the floatation access 

acreage. 

2.6.2 Effectiveness of the SP in Meeting Objectives and Goals 

1. Construct, repair or provide measures or structures necessary to protect existing wetlands 

or shorelines in the MRGO and Lake Borgne area.

The SP would provide a total of 49,280 ft (15,020 m), or approximately 9.3 miles (15.0 km), 

of shoreline protection to the critical land bridge separating Lake Borgne and the MRGO 

channel. 

2. Construct, repair, or provide measures or structures necessary to restore or increase 

wetlands in the MRGO and Lake Borgne area.

The SP would create and nourish a total of 3,345 acres (1,155 ha) of emergent wetlands. 

3. Construct, repair, or provide measures or structures necessary to reduce or prevent 

saltwater intrusion or storm surge in the MRGO and Lake Borgne area. 

The SP would protect the integrity of the land bridge separating Lake Borgne and the 

MRGO channel, thus preventing the increase in salinity that would result from its 

degradation. 

4. Construct, repair, or provide measures or structures necessary to prevent the coalescence of 

MRGO and Lake Borgne. 

The SP would provide a total of 49,280 ft (15,020 m) of shoreline protection to the critical 

land bridge separating Lake Borgne and the MRGO channel as well as create and nourish a 

total of 3,345 acres (1,155 ha) of emergent wetlands in this land bridge. These features 

would protect the integrity of the land bridge. 

5. Construction completion would be in the near-term timeframe.

Construction start times are estimated to be 3 to 6 months for shoreline protection and 9 to 

12 months for marsh creation features. Construction duration for these features would be 

less than one year. 

6. Proposed action supports other restoration plans (e.g., Coast 2050, LCA, CWPPRA, 

Louisiana State Master Plan) and complements constructed or authorized for construction 

projects such as the CWPPRA PO-30 and PO-32 shoreline protection projects along 

Lake Borgne. 

The features of the SP would interact synergistically with other constructed or authorized 

projects to provide more complete protection to the land bridge. 

7. NEPA requirements complete or would be completed within a short period of time. 

The Record of Decision for the SP would be completed before the end of March 2009. 

8. Proposed action could be accomplished within the $75 million authorized funding limit.

The construction costs of the SP would be $52,000,000, which can be accomplished within 

the $75 million authorized, after accounting for planning, design, and supervision and 

administration costs. 
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2.6.3 Effectiveness of the SP in Meeting Environmental Operating Principles 

1. Strive to achieve environmental sustainability, and recognize that an environment 

maintained in a healthy, diverse, and sustainable condition is necessary to support life. 

The SP would create, nourish, and protect 2,162 acres (876 ha) more than the No-Action 

Alternative. This additional wetland habitat would support the wildlife and fishery species 

that use this habitat. 

2. Recognize the interdependence of life and the physical environment, and proactively 

consider environmental consequences of USACE programs and act accordingly in all 

appropriate circumstances. 

The SP would contribute to the protection of the critical land bridge separating Lake Borgne 

from the MRGO channel, which would work synergistically with other projects and 

programs to maintain landscape features in the vicinity as well as provide habitat for 

resident and migrant populations. 

3. Seek balance and synergy among human development activities and natural systems by 

designing economic and environmental solutions that support and reinforce one another.

The SP would help protect commerce along the GIWW by reinforcing the land bridge that 

provides protection to the inland waterways in the vicinity. 

4. Continue to accept corporate responsibility and accountability under the law for activities 

and decisions under our control that impact human health and welfare and the continued 

viability of natural systems. 

The SP features would work synergistically with the proposed total closure structure on the 

MRGO south of Bayou La Loutre and the proposed diversion near Violet, Louisiana, to 

provide the maximum benefit for this area. 

5. Seek ways and means to assess and mitigate cumulative impacts to the environment and 

bring systems approaches to the full life cycle of our processes and work.

The SP would increase the quality and quantity of wetland habitats in the project area and 

would not have any long-term adverse cumulative impacts. 

6. Build and share an integrated scientific, economic, and social knowledge base that supports 

a greater understanding of the environment and impacts of our work.

Information gained through the planning, design, and implementation of the SP would be 

made available to other agencies and institutions to broaden the understanding of wetland 

restoration. 

7. Respect the views of individuals and groups interested in USACE activities, listen to them 

actively, and learn from their perspective in the search to find innovative win-win solutions 

to the Nation’s problems that also protect and enhance the environment.

The scoping process and public review of the Environmental Impact Statement will help 

identify the views of individuals and groups, and the planning approach will include 

addressing those views and comments. 

2.6.4 Project Costs 

The total implementation cost for the SP is estimated to be $62,400,000. The cost breakdown of 

the plan features is presented in Table 2.9. These costs are based on February 2008 price 

levels, and are subject to change prior to construction. 
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Table 2.9 Cost of Selected Plan by Project Feature 

Project Name Project Costs 

Golden Triangle Marsh Creation and Nourishment $18.0 million

Shell Beach Vicinity Marsh Creation and Nourishment $10.0 million

Lake Borgne Shoreline Protection, Bayou Bienvenue 

Vicinity 

$8.0 million

Lake Borgne Shoreline Protection, Bayou Dupre Vicinity $8.0 million

Lake Borgne Shoreline Protection, West of Shell Beach $8.0 million

Subtotal of Construction Costs $52.0 million

Contingencies (20%) $10.4 million

TOTAL PROJECT COST $62.4 million

2.6.5 Plan Implementation and Accomplishments 

The SP would be constructed using two contracts. One contract would be used to dredge access 

channels and floatation channels along the Lake Borgne shoreline, and place the rock for 

shoreline protection features. Another contract would be used for the wetland creation and 

nourishment features, including site preparation (e.g., retention structures, if any), pipeline 

layout, and dredging of the borrow sites. 

The proposed Lake Borgne Shoreline Protection, West of Shell Beach feature would be the first 

project feature constructed, and would consist of the construction of 15,400 lf (4,694 m) of rock 

dike to halt wind-driven wave erosion. Construction access would be from Lake Borgne via 

constructed floatation channels, which could require dredging up to 35.4 acres (14.3 ha) of lake 

bottom to –7 ft (–2.1 m) NAVD88. Material from the floatation channels would be used 

beneficially between the rock dike and the existing shoreline to create additional marsh to the 

maximum extent practicable. Up to 24.0 acres (9.7 ha) of saline marsh may be created using 

this material beneficially, but the exact amount will not be known until construction is 

completed. Because of this uncertainty, these potential acres are not counted in the net acreage 

benefit for this feature. Material unable to be used beneficially will be stockpiled adjacent to 

the floatation channel and returned after construction. Using the current average erosion rate of 

11 ft/yr (3.4 m/yr) for this reach of the Lake Borgne shoreline, this measure would have a net 

benefit of 101 acres (41 ha) of brackish marsh with a net value of 28 AAHU over the 50-year 

project life. Construction of this feature is expected to take approximately 9-12 months. 

The proposed Lake Borgne Shoreline Protection, Vicinity Bayou Dupre feature would be the 

constructed after the West of Shell Beach reach, and would consist of the construction of 

17,650 lf (5,379 m) of rock dike to halt wind-driven wave erosion. Construction access would 

be from Lake Borgne via constructed floatation channels, which could require dredging up to 

38.0 acres (15.4 ha) of lake bottom to –7 ft (–2.1 m) NAVD88. Material from the floatation 

channels would be used beneficially between the rock dike and the existing shoreline to create 

additional marsh to the maximum extent practicable. Up to 20.7 acres (8.4 ha) of brackish 

marsh may be created using this material, but the exact amount will not be known until 

construction is completed. Because of this uncertainty, these potential acres are not counted in 
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the net acreage benefit for this feature. Material unable to be used beneficially will be 

stockpiled adjacent to the floatation channel and returned after construction. Using the current 

average erosion rate of 7 ft/yr (2.1 m/yr) for this reach of the Lake Borgne shoreline, this 

measure would have a net benefit of 73 acres (30 ha) of brackish marsh with a net value of 

21 AAHU over the 50-year project life. Construction of this feature is expected to take 

approximately 9-12 months. 

The proposed Lake Borgne Shoreline Protection, Vicinity Bayou Bienvenue feature would be 

the last shoreline protection reach constructed, and would consist of the construction of 

16,230 lf (4,947 m) of rock dike to halt wind-driven wave erosion. Construction access would 

be from Lake Borgne via constructed floatation channels, which could require dredging up to 

33.8 acres (13.7 ha) of lake bottom to –7 ft (–2.1 m) NAVD88. Material from the floatation 

channels would be used beneficially between the rock dike and the existing shoreline to create 

additional marsh to the maximum extent practicable. Up to 21.5 acres (8.7 ha) of brackish 

marsh is anticipated to be created using this material, but the exact amount will not be known 

until construction is completed. Because of this uncertainty, these potential acres are not 

counted in the net acreage benefit for this feature. Material unable to be used beneficially will 

be stockpiled adjacent to the floatation channel and returned after construction. Using the 

current average erosion rate of 10 ft/yr (3.0 m/yr) for this reach of the Lake Borgne shoreline, 

this measure would have a net benefit of 96 acres (39 ha) of brackish marsh with a net value of 

28 AAHU over the 50-year project life. Construction of this feature is expected to take 

approximately 9-12 months. 

The Shell Beach Marsh Creation and Nourishment feature would be the first wetland creation 

and nourishment feature to be constructed, and would take approximately 9-12 months to 

complete. Approximately 8.3 acres (3.4 ha) of floatation access channels would need to be 

dredged, via clamshell or bucket dredge, to –7 ft (–2.1 m) NAVD88 to provide access for the 

hydraulic dredging plant in Lake Borgne. Pipelines would be assembled on site and extend 

from the dredging plant to the wetland creation cells (five discrete areas of open water and 

surrounding saline marsh), using the most efficient routes that provide minimal environmental 

disturbance. Some earthen retention dikes would be required for containment, and natural 

ridges would be used where possible. In one location, installation of sheetpiles or a rock dike 

may be necessary to provide containment for dredged material. Spill box weirs would be 

constructed as needed to properly allow the water to drain from the sites. Material from within 

the three identified borrow sites (Figure 2.5) would be hydraulically dredged from the lake 

bottom and pumped via pipeline to the wetland creation cells. The dredged-material slurry 

would be pumped directly into the open water areas within the cells to an elevation of 

approximately +3.2 ft (1.0 m) NAVD88 and the effluent would be allowed to flow over adjacent 

wetlands for marsh nourishment. Material that is placed over existing marsh will not exceed 

1 ft (0.3 m) above the existing marsh elevation. The discharge of the pipeline would be 

relocated as needed to prevent overfilling and to ensure each cell receives adequate material. 

Approximately 3,200,000 cy (2,443,366 cubic meters) would be required to restore 

approximately 425 acres (172 ha) of saline marsh, as well as nourish approximately 270 acres 

(109 ha) of adjacent wetlands, within the narrow land bridge in the vicinity of Yscloskey and 

Fort Beauregard. The net benefit of this measure over the project life would be 397 acres and 

256 AAHU compared to the No-Action Alternative. 
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The Golden Triangle Marsh Creation and Nourishment feature would be the last project feature 

to be constructed, and would take approximately 9-12 months to complete. Approximately 

2.8 acres (1.1 ha) of floatation access channels would need to be dredged, via clamshell or 

bucket dredge, to provide access for the hydraulic dredging plant in Lake Borgne. Pipelines 

would be assembled on site and extend from the dredging plant to the wetland creation cell, 

using the most efficient route that provides minimal environmental disturbance. Approximately 

51,000 ft (15,544 m) of earthen retention dikes would be required for containment, and natural 

ridges would be used where possible. Spill box weirs would be constructed as needed to 

properly allow the water to drain from the site. Material from within the borrow site would be 

hydraulically dredged from the lake bottom and pumped via pipeline to the wetland creation 

cell. The dredged-material slurry would be pumped directly into the open water areas within 

the cell to an elevation of approximately +3.2 ft (1.0 m) NAVD88 and the effluent would be 

allowed to flow over adjacent wetlands for marsh nourishment. Material that is placed over 

existing marsh will not exceed 1 ft (0.3 m) above the existing marsh elevation. The discharge of 

the pipeline would be relocated as needed to prevent overfilling and to ensure the entire cell 

receives material. Approximately 6.5 million cy (4,963,088 cubic meters) would be required to 

restore approximately 1,250 acres (506 ha) of brackish marsh, as well as nourish an estimated 

additional 1,400 acres (567 ha) of non-contiguous marsh. The net benefit of this measure over 

the project life would be 1,495 acres (606 ha) and 856 AAHU compared to the No-Action 

Alternative. 

2.6.6 Summary of Selected Plan Accomplishments 

In summary, the Selected Plan would create, nourish and protect a net of 2,162 acres (876 ha) 

compared to the No-Action Alternative over the 50-year period of analysis. It would take 18 to 

24 months to complete all of the construction features, due to overlap of the construction 

schedules. The increased acreage of brackish and saline marshes would provide additional 

habitat for fish and wildlife species, as well as protect the land bridge between Lake Borgne and 

the MRGO channel. The land bridge also protects navigation (commercial and recreational) 

utilizing adjacent reaches of the GIWW from wind-driven waves in Lake Borgne. The SP 

would accomplish this in a cost-effective manner, with an average approximate cost of 

$24,052 per net acre ($59,367 per net ha), or $13,447 per acre ($33,191 per ha) initially created, 

nourished, or protected.