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Drawing Louisiana's New Map: Addressing Land Loss in Coastal Louisiana (2006)

Chapter: 5 The LCA Study Planning Approach, Modeling, and Project Selection Process

« Previous: 4 Plans and Efforts at Restoring Coastal Louisiana
Suggested Citation:"5 The LCA Study Planning Approach, Modeling, and Project Selection Process." National Research Council. 2006. Drawing Louisiana's New Map: Addressing Land Loss in Coastal Louisiana. Washington, DC: The National Academies Press. doi: 10.17226/11476.
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5
The LCA Study Planning Approach, Modeling, and Project Selection Process

HIGHLIGHTS

This chapter

  • Addresses issues associated with the planning approaches proposed in the Louisiana Coastal Area (LCA), Louisiana—Ecosystem Restoration Study (LCA Study) to counter serious land loss rates

  • Examines past and proposed efforts to engage stakeholders

  • Discusses models used in the project selection process and identifies their strengths and weaknesses

  • Examines the overall project selection process

In an area as vast and complex as the Louisiana coastal region, planning for restoration is a challenge. The fields of ecology, wetland science, hydrology, geology, oceanography, computer modeling, engineering, sociology, economics, political science, land-use planning, hazard mitigation, and law can make a contribution in defining the problem and providing possible solutions; therefore, these fields must be considered in the design process.

Suggested Citation:"5 The LCA Study Planning Approach, Modeling, and Project Selection Process." National Research Council. 2006. Drawing Louisiana's New Map: Addressing Land Loss in Coastal Louisiana. Washington, DC: The National Academies Press. doi: 10.17226/11476.
×

CONTEXT FOR PLANNING

State Legal System and Issues

Planning takes place in the context of laws governing land-use and property rights, as well as the institutional arrangements of federal, state, and local government. Louisiana, by virtue of its history as a French colony, has its law based on the Napoleonic Code rather than English common law, which is found in the rest of the United States. In the English common law tradition, the judiciary acts as a check on both the executive and legislative branches, limiting their ability to alter contract and property rights. Judges, in this system, use common practice and court precedent to interpret laws. Napoleonic Code takes the civilian law approach, based on scholarly research and the intent of the lawmakers. The French tradition is more comfortable with a centralized and activist government, limiting the judiciary’s role to ensuring that the will of the government is enforced (Benjamin, 2001). These differences in philosophy influence judicial decisions regarding compensation of landowners or other aspects of citizen rights.

Most of coastal Louisiana is privately owned or at least subject to some claim of private ownership (Davis, 2002). Much of the coastal land is owned for its underlying minerals (i.e., oil and gas). However, Louisiana claims ownership over navigable water bottoms including lands that have been submerged through erosion or subsidence (U.S. Army Corps of Engineers, 2004a). According to the Louisiana Constitution (Article IX, Section 3), owners of land contiguous to and abutting navigable waters owned by the state “shall have the right to reclaim or recover land lost through erosion, compaction, subsidence, or sea level rise occurring on or after July 1, 1921. Such private efforts to restore or reclaim lost lands can be made at any time” (Act 6, Louisiana Wetlands Conservation and Restoration Act, 1989; U.S. Army Corps of Engineers, 2004a). In the cases of subsided interior marshes, the State of Louisiana does not assert or claim ownership that it could, given the navigable standard.

Coastal restoration projects may impinge on private reclamation rights. The Louisiana Wetlands Conservation and Restoration Act of 1989 provides “that [the Louisiana Department of Natural Resources] may enter into negotiated boundary agreements with such disaffected landowners to address the anticipated loss of their ownership and reclamation rights” (Act 6, Louisiana Wetlands Conservation and Restoration Act, 1989; U.S. Army Corps of Engineers, 2004a) where the LCA Study is anticipating creating land. It is still possible that when land emerges from water bottoms claimed by Louisiana, the previous landowner may at-

Suggested Citation:"5 The LCA Study Planning Approach, Modeling, and Project Selection Process." National Research Council. 2006. Drawing Louisiana's New Map: Addressing Land Loss in Coastal Louisiana. Washington, DC: The National Academies Press. doi: 10.17226/11476.
×

tempt to claim that he was deprived of his reclamation rights to the emergent land.

Mineral rights (e.g., oil and gas) are not extinguished when land is flooded. The mineral rights are not acquired when the state or federal government purchases the land by fee simple, which means there are no restrictions on the transfer of ownership. Thus, the mineral rights would be expressly reserved to the previous landowner or to the lessee of those mineral interests. The mineral interest owner or lessee would be allowed to continue ongoing mineral activities. Lands and improvements actually used or destroyed for levees or levee drainage purposes shall be paid for as provided by law (Louisiana Constitution [1974], Art VI, §42).

Louisiana’s judicial system has been used to settle claims from landowners suffering damage as a result of coastal restoration activities. A constitutional amendment passed in 2003 limits Louisiana’s liability for damages caused by coastal restoration projects to the land’s fair market value in line with federal standards, and it applies retroactively (Louisiana Constitution [1974], Amendment I, §42). This amendment was in response to a $2 billion judgment by a state court that sided with the oyster growing and harvesting interests who claimed that their oyster beds were destroyed by the Caernarvon freshwater diversion. The Louisiana Supreme Court reversed the decision. As a result, program feasibility and costs will be contingent upon the legal and legislative rulings and actions that frame the planning exercise. When mineral rights are affected or damages to preexisting shellfish or fishing activities are caused by wetland restoration activities, the planners will have to incorporate institutional changes and financial compensatory elements into the planning process.

Array of Agencies and Interests

Coastal restoration, as envisioned by the LCA Study, involves federal, state, and local governments. The projects being proposed in the LCA Study will impact, both positively and negatively, the finfish and shellfish industry, the gas and oil industry, the petrochemical industry, banking, agriculture, shipping, recreation, and the everyday life of local residents. The projects will require the purchase of land and the resettlement of homes and businesses. Environmental organizations will be involved as habitats are changed and restored. There will be tension between those that have adjusted to the land loss and salinity change by changing their occupations and lifestyle and those that will benefit from land restoration and the increasing freshness of the waterways.

Because dramatic changes are envisioned by the LCA Study, it will alter the way people live, work, and play; those impacted will have to be

Suggested Citation:"5 The LCA Study Planning Approach, Modeling, and Project Selection Process." National Research Council. 2006. Drawing Louisiana's New Map: Addressing Land Loss in Coastal Louisiana. Washington, DC: The National Academies Press. doi: 10.17226/11476.
×

convinced of the benefits and agree to change their lifestyles. Therefore, the LCA Study is about both technical challenges and social, economic, and political challenges. Consensus building, through education, discussion, and trust, can be partially effective in building the cooperation necessary for coastal restoration to be successful. This cooperation requires outreach by state and federal agencies to educate local governments (elected officials and staff) and to gain the local governments’ perspectives. The three levels of government will also have to educate and involve the public, listen to public concerns, and work with the public to overcome inequities.

The Nature of Planning

The planning process utilized in the LCA Study is designed to find the plan that best meets planning objectives. The stated overarching objective is “to reverse the current trend of degradation of the coastal system” (U.S. Army Corps of Engineers, 2004a). The planning process is best described by planning theory as “rational” or “synoptic.” The emphasis in this approach is to define the problem, develop strategies to resolve the problem, evaluate alternatives to find the “best” strategy, and then adopt and implement it. This rational planning process is appropriate for complex technical problems such as restoring the coast; however, it is less successful when the problem is “wicked” and highly political. Wicked problems, as described by Rittel and Webber (1973), are ill-defined; often lack consensus regarding their causes, obvious solutions, and criteria for determining when a solution has been achieved; and have numerous, often unknown, interconnections to other processes and problems. To determine whether or not the loss of Louisiana’s wetlands is a wicked problem, one has only to ask what the solution to the problem is, and the debate begins regardless of whether the participants are seasoned researchers or laypersons. The fact that the problem is highly political is obvious because whatever the solutions, some people will gain, and others will lose. The political system becomes engaged because in a democracy, politics is used to mediate between those who benefit and those who pay since those who pay the price for improvements may not be the ones that receive the benefits. “Pay” does not just mean money but also means inconvenience, time, and exposure to hazards.

Increasingly, planners have recognized that simply telling people what they have to do because it is the “right” thing does not work well in a democracy. It appears that people have to adopt the ideas as their own and be committed to changing, even if it makes life less convenient and incurs a cost, if major plans and projects are to succeed. Communicative planning, advocated by Innes (1995, 1998), is built on information ex-

Suggested Citation:"5 The LCA Study Planning Approach, Modeling, and Project Selection Process." National Research Council. 2006. Drawing Louisiana's New Map: Addressing Land Loss in Coastal Louisiana. Washington, DC: The National Academies Press. doi: 10.17226/11476.
×

change between experts and citizens. It is not just an exchange of words but reflects a variety of institutional, political, and power relationships. During the course of these exchanges, a shared sense of meaning develops, and subsequent actions will be heavily influenced by this shared understanding (Brooks, 2002). “The planner who follows this approach is not an analyst working behind closed doors to eventually produce the most rational recommendations but an active and intentional participant in a process of public discourse and social change” (Ozawa and Seltzer, 1999). These sociopolitical challenges can be overcome if a robust adaptive management effort, which includes adequate mechanisms for addressing the full range of challenges, is employed.

ROLE OF MODELS IN THE PLANNING AND ADAPTIVE MANAGEMENT OF THE LCA STUDY PLANNING PROCESS

Models have been used in attempts to understand the physical processes within the project area, for the development of the Louisiana Coastal Area, LA—Ecosystem Restoration: Comprehensive Coastwide Ecosystem Restoration Study (draft LCA Comprehensive Study), and for project selection and prioritization of actions within the LCA Study, and they are expected to be part of the future Adaptive Environmental Assessment and Management (AEAM) Program called for in the LCA Study. The draft LCA Comprehensive Study was used to create the LCA Study as a near-term alternative to its predecessor. (For additional background, refer to Chapter 3.) These models were assembled in the period August 2002 to September 2003 (U.S. Army Corps of Engineers, 2003a), and model selection was based primarily on those available from previous studies by academia and state and federal agencies and on model integration and development that could be achieved in the available time. If the models are to be an integral part of the management process, it is important that they be credible and robust representations of the environmental and economic processes they are intended to represent.

In complex long-term projects, modeling1 can be a valuable aid to managers for the following reasons:

  • Generate agreement on the important processes determining the response of a system to natural and anthropogenic perturbations

1  

General characterization of a process, object, or concept in verbal or mathematical terms, which enables the relatively simple manipulation of variables to be accomplished in order to determine how the process, object, or concept would behave in different situations (Office of Administrative Law Judges Law Library, 1991).

Suggested Citation:"5 The LCA Study Planning Approach, Modeling, and Project Selection Process." National Research Council. 2006. Drawing Louisiana's New Map: Addressing Land Loss in Coastal Louisiana. Washington, DC: The National Academies Press. doi: 10.17226/11476.
×
  • Project future conditions under different scenarios, including “no action”

  • Allow performance criteria to be quantified and tracked

  • Develop temporal and spatially distributed understanding not possible by monitoring alone

  • Optimize data collection programs

  • Evaluate sensitivity and uncertainty

  • Clarify the assumptions and their influence on results

  • Facilitate cross-disciplinary communication and explain processes to nontechnical audiences

  • Assist real-time emergency management during severe flood or storm surge conditions

The use of models and a sensor network for real-time emergency response is self-evident and should be addressed by the science coordination team (U.S. Army Corps of Engineers, 2004a) as the suite of models for the LCA Study are refined in the future; thus, they are not explored further in this report. The central role of modeling in the proposed AEAM Program (Figure 5.1) is described in the LCA Study and discussed further in this report. The use of models in predicting whether the future preferred landscape dynamic is achievable and how projects should be selected is discussed in Chapter 6. The suite of models used to develop the linkages between physical processes and ecological response is shown in Figure 5.2.

Types of Models

The LCA Study modeling team differentiates between two types of modeling efforts (Figure 5.3). The first is simulation modeling, which is predictive, deterministic, and process-based (U.S. Army Corps of Engineers, 2003a). “Simulation modeling represents the highest level of sophistication in ecological modeling where clearly defined assumptions of ecological mechanisms are linked to geophysical process. These models can be used to simulate the endpoints of engineering alternatives” (U.S. Army Corps of Engineers, 2003a). The hydrological models are simulation models. Less sophisticated are the hydrological box models that can predict endpoints of salinity, hydroperiod, and sedimentation over longer time scales and at a coarse spatial resolution.

In the second type of modeling used in the LCA Study process, empirical information was used to statistically estimate ecosystem responses to various changes in the environment. This type of model is called a desktop model. The coarse-scale “desktop” statistical approach might use spreadsheets and is based on reported relationships in various literature

Suggested Citation:"5 The LCA Study Planning Approach, Modeling, and Project Selection Process." National Research Council. 2006. Drawing Louisiana's New Map: Addressing Land Loss in Coastal Louisiana. Washington, DC: The National Academies Press. doi: 10.17226/11476.
×

FIGURE 5.1 The Science and Technology Program approach proposed for developing comprehensive ecosystem restoration plans for the LCA Study (U.S. Army Corps of Engineers, 2004a; used with permission from the U.S. Army Corps of Engineers).

sources, data, and best professional judgment. A goal of the LCA Study is to eventually develop and use simulation models for all five modules across all four regions (U.S. Army Corps of Engineers, 2003a).

Goal of Modeling

The goal of the modeling effort was to develop quantifiable benefits, or outputs, of the plan based on purely ecological criteria. The following are these criteria:

Suggested Citation:"5 The LCA Study Planning Approach, Modeling, and Project Selection Process." National Research Council. 2006. Drawing Louisiana's New Map: Addressing Land Loss in Coastal Louisiana. Washington, DC: The National Academies Press. doi: 10.17226/11476.
×
  • Land building measured in acres

  • Habitat switching measured as change of habitat types in acres

  • Primary productivity of land and water measured as an index of composite plant productivity

  • Habitat use measured in habitat units for selected species

  • Removal of nitrogen from the Mississippi River measured as a percentage of nutrients removed (U.S. Army Corps of Engineers, 2004a)

Specifics of the Models

The LCA Study’s ecosystem model was the product of a team of more than 38 scientists, engineers, and resource managers, primarily from Louisiana. Subgroups of technical experts were assembled in a workshop to develop algorithms for each of the five modules of the ecosystem model (Figure 5.2). Because of the size of the study area and the schedule, the model was a hybrid of simulation and desktop modeling (Figure 5.3). These subgroups were responsible for integrating expertise among university and agency scientists and interfaced closely with the LCA Study managers to develop appropriate modeling scenarios.

FIGURE 5.2 Linkage of different modules used in desktop and simulation models (U.S. Army Corps of Engineers, 2004a; used with permission from the U.S. Army Corps of Engineers).

Suggested Citation:"5 The LCA Study Planning Approach, Modeling, and Project Selection Process." National Research Council. 2006. Drawing Louisiana's New Map: Addressing Land Loss in Coastal Louisiana. Washington, DC: The National Academies Press. doi: 10.17226/11476.
×

FIGURE 5.3 Hybrid of desktop and simulation modeling tools for benefit evaluation used in the LCA Study (U.S. Army Corps of Engineers, 2004a; used with permission from the U.S. Army Corps of Engineers).

Suggested Citation:"5 The LCA Study Planning Approach, Modeling, and Project Selection Process." National Research Council. 2006. Drawing Louisiana's New Map: Addressing Land Loss in Coastal Louisiana. Washington, DC: The National Academies Press. doi: 10.17226/11476.
×

A spatial orientation was included in the modeling of ecosystem responses. The study area was divided into 1 square kilometer (km2) (0.39 square miles [mi2]) polygons resulting in 43,138 coastal area cells. Although 1 km2 (0.39 mi2) is reasonable for modeling, it results in problems of land classification and resolution of processes at subgrid scale. For example, a cell was identified as a “water cell” if it contained more than 0.40 km2 (0.15 mi2) of open water, with all other cells identified as non-water and classified as the vegetation type that covered the most area in the cell (U.S. Army Corps of Engineers, 2003a).

Additionally, each of the four LCA Study’s regions was partitioned into boxes. Either boxes were constructed to fit previous conventions of box construction, or vegetation maps were used to distinguish zones of salinity regimes in the coastal landscape. A major assumption is that all the land cells of each box will respond to the results of nodes in respective boxes.

The LCA Study’s ecosystem model is made up of a number of different models (or modules) that feed into one another (Figures 5.2 and 5.3). This generalized picture does not reflect the detail of the modules. For example, the hydrodynamic portion of the ecosystem model comprises five different models selected from previous studies (Figure 5.3):

  • Region 1—Princeton Ocean Model was developed by Blumberg and Mellor (1987). This is a three-dimensional sigma coordinate primitive variable model. Data were available for validation only for the Lake Pontchartrain area (Figure 5.4).

  • Region 2—TABS-MD (RMA 2, RMA 4) developed by the U.S. Army Corps of Engineers (USACE). This model relies on a central two-dimensional, finite-element representation of estuarine and fluvial hydrodynamics and was used for the lower two-thirds of the Barataria Basin.

  • Region 3—Coastal Ecological Landscape Spatial Simulation model (Sklar et al., 1985; Costanza et al., 1987, 1989) was the initial model applied to Terrebonne watershed. This model evolves the landscape composition according to explicit rules and formulas, and results are calibrated against the record of past landscape change and forced by a continuous hydrodynamic simulation (Martin et al., 2000; Reyes et al., 2003).

  • Region 4—H3D (Stronach et al., 1993) is a three-dimensional hydrodynamic and advection dispersion model used to study the Calcasieu-Sabine Basin. MIKE-11, produced by the DHI (Danish Hydraulic Institute) Water and Environment, was used to simulate flows, sediment transport, and water quality in the Rockefeller Refuge. It is composed of two dynamically linked modules—the hydrodynamic module and the advection dispersion module.

Suggested Citation:"5 The LCA Study Planning Approach, Modeling, and Project Selection Process." National Research Council. 2006. Drawing Louisiana's New Map: Addressing Land Loss in Coastal Louisiana. Washington, DC: The National Academies Press. doi: 10.17226/11476.
×

FIGURE 5.4 Deterministic models of the Louisiana coastal area (background map supplied by Research Planning, Inc.).

The objectives of the original model studies varied for the regions and covered differing amounts of the coast. Figure 5.4 illustrates that large gaps within the Louisiana coastal area are not covered by deterministic models. Because of the differing objectives of the models selected, there is no consistency in the selection of bathymetry (where available), period of time the models simulate, and boundary conditions. However, this preliminary phase of modeling has identified gaps in essential data, demonstrated the most important processes that should be included in a model formulation, and generated experience in the use of a broad range of one-dimensional, two-dimensional, and three-dimensional models. These experiences will be invaluable when the science coordination team (Figure 4.5) establishes a consistent modeling approach for the entire project area.

Table 5.1 lists all of the variables that were used in the five general models: hydrodynamics, land change, water quality, habitat switching, and habitat use.

The compilation of the conceptual approach and the model application represent a significant amount of modeling work and coordination to quantify the outputs of each of the features and frameworks. The integrated modeling exercise has been ambitious, and the modeling team has achieved much and should be commended for articulating a comprehen-

Suggested Citation:"5 The LCA Study Planning Approach, Modeling, and Project Selection Process." National Research Council. 2006. Drawing Louisiana's New Map: Addressing Land Loss in Coastal Louisiana. Washington, DC: The National Academies Press. doi: 10.17226/11476.
×

TABLE 5.1 Module Variables and Interactions Among Modules

Variable

Module

Hydrodynamics

Land Change

Water Quality

Habitat Switching

Habitat Use

Wind speed and direction

Input

 

 

 

 

Initial water level

Input

 

 

 

 

Initial salinity

Input

Inputa

 

 

 

Initial temperature

Input

 

 

 

 

River temperature

Input

 

 

 

 

Historical land change rates

 

Input

 

 

 

River sediment load

 

Input

 

 

 

Sediment retention factor

 

Input

 

 

 

Bulk density of deltaic soils

 

Input

 

 

 

Initial land area

Input

Input

 

 

 

Bathymetry

Input

Input

Input

 

 

Land elevation

Input

Input

Input

Input

Input

Diversion flows

Input

Input

Input

 

 

River nitrogen

 

 

Input

 

 

Nourishment factor

Outputa

Input

 

 

 

Salinity

Output

 

Input

Input

Input

Water level

Output

 

Input

Input

Input

Water residence time

Output

 

Input

 

 

Water temperature

Output

 

Input

 

Input

Suggested Citation:"5 The LCA Study Planning Approach, Modeling, and Project Selection Process." National Research Council. 2006. Drawing Louisiana's New Map: Addressing Land Loss in Coastal Louisiana. Washington, DC: The National Academies Press. doi: 10.17226/11476.
×

Wetland area

 

Output

Input

Input

Input

Habitat type

 

 

 

 

Input

Nitrogen removal

 

 

Output

 

 

Water primary production

 

 

Output

 

 

Wetland primary production

 

 

 

Output

 

Chlorophyll a water columnb

 

 

 

 

 

Habitat quality, alligator

 

 

 

 

Output

Habitat quality, dabbling duck

 

 

 

 

Output

Habitat quality, mink

 

 

 

 

Output

Habitat quality, muskrat

 

 

 

 

Output

Habitat quality, otter

 

 

 

 

Output

Habitat quality, Atlantic croaker

 

 

 

 

Output

Habitat quality, brown shrimp

 

 

 

 

Output

Habitat quality, gulf menhaden

 

 

 

 

Output

Habitat quality, largemouth bass

 

 

 

 

Output

Habitat quality, oyster

 

 

 

 

Output

Habitat quality, spotted seatrout

 

 

 

 

Output

Habitat quality, white shrimp

 

 

 

 

Output

aIn regions 1, 2, and 3, the nourishment factor refers to freshwater and is based on the initial salinity of the receiving basin. In region 4, the nourishment factor is based on the change in salinity relative to the no-action scenario.

bNo value provided in source.

SOURCE: U.S. Army Corps of Engineers, 2003a.

Suggested Citation:"5 The LCA Study Planning Approach, Modeling, and Project Selection Process." National Research Council. 2006. Drawing Louisiana's New Map: Addressing Land Loss in Coastal Louisiana. Washington, DC: The National Academies Press. doi: 10.17226/11476.
×

sive approach. The modeling team2 has clearly described and referenced the models in an attempt to be as transparent as possible. Uncertainties and gaps in knowledge have been systematically identified (U.S. Army Corps of Engineers, 2003a). In the very short time frame (13 months) of this initiative, much has been achieved in assembling data and understanding how results will be interpreted.

Challenges

Several challenges are posed by the current approach to modeling that distinguish this effort from similar studies elsewhere in the United States. These challenges are as follows:

  • The study area, even when broken into the four regions, is still at a massive spatial scale for simulation models. Keeping track of 43,138 units, each with an area of 1 km2 (0.39 mi2), can be overwhelming.

  • The landscape is difficult to work in due to problems (private lands and rough terrain) in accessing all sectors. This makes it difficult to accurately characterize open boundaries, and small errors can be magnified as they cascade through the linked models.

  • The problem of coastal land loss is severe and immediate so restoration decisions have been, and will continue to be, made before model calibration and algorithm development can occur. For example, no sensitivity analyses have been run on the land-building module, habitat-switching module, water-quality module, or habitat-use module that are being used to predict outputs for different projects in coastal restoration. Decisions are being made based on these outputs, which could be largely erroneous.

  • There are limited data in many key areas. The modeling team documents a number of key data gaps (Appendix C of U.S. Army Corps of Engineers [2004a]), including no survey data for the four major lakes (White, Grand, Calcasieu, and Sabine), inadequate marsh elevation data throughout the region, and extremely limited hydrologic and ecologic data for the Region 4 marsh.

  • Several fundamental questions are yet to be resolved; however, the Science and Technology (S&T) and AEAM programs are proposed to deal with them. Some of these questions involve the transport of sediment over long distances using pipes, the effect of using marine sands on

2  

The modeling team was part of the working groups (Figure 4.4) and will be part of the Science and Technology Program (see Chapter 6) and the AEAM framework (see Chapter 6).

Suggested Citation:"5 The LCA Study Planning Approach, Modeling, and Project Selection Process." National Research Council. 2006. Drawing Louisiana's New Map: Addressing Land Loss in Coastal Louisiana. Washington, DC: The National Academies Press. doi: 10.17226/11476.
×

marshes, and the amounts and kind of sediment carried by the Mississippi River in different parts of its water column and how to use that variation to the best advantage.

Uncertainties

The draft LCA Comprehensive Study (U.S. Army Corps of Engineers, 2003a) systematically identified uncertainties3 and gaps in knowledge. Uncertainties are present in different modules in terms of the model rigor and the quality of the parameter estimates in model input. Many of the models used professional judgment as the data source (U.S. Army Corps of Engineers, 2003a). Model developers acknowledge that many of the data are of low quality and few of high quality, and they report that model rigor is moderate to low (U.S. Army Corps of Engineers, 2003a). Given the way the models were used and the multiple levels of information exchange and interaction, the errors and uncertainties will propagate through this sequence of models. There is a need to estimate the combined effects of these uncertainties on the projected outcomes and thus on the derived benefits. Appropriate project selection depends on the validity of these models, and it does not appear that the modeling results discussed in the draft LCA Comprehensive Study were modified in any way before being used for input to project selection in the LCA Study.

PROJECT SELECTION AND THE LINK WITH MODELING

The draft LCA Comprehensive Study and the LCA Study both outline in detail the methodology for project selection (U.S. Army Corps of Engineers, 2004a) (Figure 5.5). The project delivery team, which consisted of state and federal agency representatives, developed core restoration strategies for each region. Restoration “features,” specific projects or a

3  

The term “uncertainty” has a variety of definitions and uses. When dealing with numerical modeling of natural systems or economic analysis, it often refers to statistical uncertainty. For example, risk analysis from flooding uses probabilistic descriptions of the uncertainty in estimates of important variables, including flood-frequency, stage-discharge, and stage-damage relationships, to compute probability distributions of potential flood damages. These computed estimates can be used to determine a levee height that provides a specified probability of containing a given flood. The LCA Study often uses the term “uncertainty” in the broader sense and interchangeably with the term “knowledge gap” to describe instances in which insufficient understanding of underlying processes may exist. Here and throughout this report, the term “uncertainty” is used to refer to statistical uncertainty associated with a parameter of interest. The term “knowledge gap” is used to refer to an area in which understanding may be insufficient to support effective decision making.

Suggested Citation:"5 The LCA Study Planning Approach, Modeling, and Project Selection Process." National Research Council. 2006. Drawing Louisiana's New Map: Addressing Land Loss in Coastal Louisiana. Washington, DC: The National Academies Press. doi: 10.17226/11476.
×

FIGURE 5.5 Overview of the project selection process (U.S. Army Corps of Engineers, 2004a; used with permission from the U.S. Army Corps of Engineers).

Suggested Citation:"5 The LCA Study Planning Approach, Modeling, and Project Selection Process." National Research Council. 2006. Drawing Louisiana's New Map: Addressing Land Loss in Coastal Louisiana. Washington, DC: The National Academies Press. doi: 10.17226/11476.
×

FIGURE 5.6 Preliminary average annual costs and average annual benefits for the final array of alternative frameworks for Regions 1, 2, and 3 (U.S. Army Corps of Engineers, 2004a; used with permission from the U.S. Army Corps of Engineers). (NOTE: The gray line denotes the cost efficient frontier; projects that fall at the bend in the frontier provide the maximum benefit for the least cost.)

collection of elements, were then considered in more detail; a total of 166 features were considered across four regions. Features were selected based on Coastal Wetlands Planning, Protection, and Restoration Act (CWPPRA) experiences and professional judgment. These features were combined into “frameworks” or plans.4 Hydrodynamic and ecological models were then used to assess the ecological benefits of each framework. The outcomes of these models provided input for the economic model Institute of Water Resources (IWR) Plan Decision Support Software, which was used in the draft LCA Comprehensive Study and the LCA Study to establish frameworks with the lowest cost for any benefit level (Figure 5.6). Those frameworks that emerged on the cost-efficient frontier of the cost versus outputs measure were then disaggregated into features, and the features were screened by a series of criteria. The final features were ordered based on the time required for implementation, and those consistent with the available funding became the top five projects. These steps are reviewed carefully in this section because this process forms the basis for project selection for the LCA Study and is assumed to be the prototype for future plans.

4  

Features could appear in several frameworks such that each framework was simply a unique collection of features.

Suggested Citation:"5 The LCA Study Planning Approach, Modeling, and Project Selection Process." National Research Council. 2006. Drawing Louisiana's New Map: Addressing Land Loss in Coastal Louisiana. Washington, DC: The National Academies Press. doi: 10.17226/11476.
×

As shown in Figure 5.5, the models just discussed were used to calculate benefits that would be developed as a result of undertaking a “framework” or plan. The benefits were all ecological in focus (e.g., acres of habitat, percentage of nitrogen removed).

It would not have been too difficult, although perhaps more arbitrary, to include a benefits dimension for socioeconomic value as a complement to the habitat-use measure, where the “species” is humans. For example, an index of the proximity of a project area to a major urban settlement, an index of navigation protection, or the reduction in hurricane risk or river flooding would be measures that could be incorporated for cost-effectiveness analysis. Inclusion of these types of indices would probably skew project selection toward projects having more beneficial socioeconomic impacts, compared to using the initial ecological selection criteria with a “socioeconomic critical need” criterion applied only in the final steps of the analysis. Such an analysis, however, is not an essential element of projects proposed as National Environmental Restoration (NER) but is more consistent with the analysis employed when evaluating projects proposed as National Economic Development (NED).

A framework’s effectiveness was measured by a weighted sum of the five benefits (presented earlier in the “Goal of Modeling” section). The principle of relative weightings is valid and should reflect the importance of a benefits category to overall program goals. Appropriate weighting of selected outcomes used in the study, however, is not evident. For instance, does the habitat-switching measure represent a positive output (e.g., is the conversion of 1 acre [0.0040 km2; 0.0016 mi2] of salt marsh to fresh marsh given a +1 or a −1)? A human-based weighting may differ substantially from a purely ecological-based weighting. Removal of nitrogen may be highly important to the fisheries but not to storm protection. Does the weighting imply something about the importance of various socioeconomic activities dependent on the coast? Furthermore, it is not evident how the ecological-based weights were selected, because weights should reflect the value of an output with respect to a goal, and the purely ecological goal of an ecosystem is not evident. In any case, given these reservations, it would be mandatory to test different weighting schemes in order to determine how sensitive the prioritization of frameworks and their projects is to these weightings. No evidence is presented in the LCA Study that this was done.

A more technical, but important, consideration in the benefits analysis process is whether the scoring of the different benefit dimensions was scaled appropriately so that benefit categories would not receive undue weightings. For example, was each of the scoring dimensions scaled as 0–1 or 0–100? This scaling is important; otherwise, a combination of misscaled measures plus the importance weighting would result in total

Suggested Citation:"5 The LCA Study Planning Approach, Modeling, and Project Selection Process." National Research Council. 2006. Drawing Louisiana's New Map: Addressing Land Loss in Coastal Louisiana. Washington, DC: The National Academies Press. doi: 10.17226/11476.
×

benefits scores of projects that reflect a meaningless combination of relatively arbitrary scoring and importance. The technical studies describing the ecological or physical scoring did not describe the scaling applications; thus, it is not clear how the scaling issue was addressed.

Economic Analysis

Using project costs and these weighted benefits (output) measures by framework, USACE used the computer model IWR Plan to establish combinations of frameworks and their cost-effectiveness. These costs and benefits are shown in Figure 5.6.

The cost-efficient frontier defines those combinations of frameworks with the lowest cost for any benefit level and the highest benefit for any cost level. The LCA Study consisted of frameworks selected from, or near, this frontier. Several of these cost-effective frameworks were excluded for varying reasons. For example, some could be funded under CWPPRA, and others would not provide substantial storm surge protection. These exclusions resulted in six plans, and two more were added for a total of eight.

Filtering Criteria

Project framework combinations that met the cost-effectiveness were next evaluated using the following three criteria:

  1. Would implementation reduce land loss by at least half the current rate?

  2. Would implementation provide storm surge protection and protect navigation?

  3. Would implementation add environmentally important features?

One framework was eliminated at this point (no explanation provided), leaving seven combinations for further consideration (U.S. Army Corps of Engineers, 2003a). These seven frameworks consist of 79 features out of the original 166. Socioeconomic values of storm and navigation protection are introduced as sorting criteria at this stage. This is also where projects for inclusion in the draft LCA Comprehensive Study stopped. Therefore, the following discussion applies to how information developed for the draft LCA Comprehensive Study was used to formulate the near-term priorities laid out in the LCA Study.

The 79 projects were then sorted (filtered) for their inclusion in the LCA Study, first using the following criteria:

Suggested Citation:"5 The LCA Study Planning Approach, Modeling, and Project Selection Process." National Research Council. 2006. Drawing Louisiana's New Map: Addressing Land Loss in Coastal Louisiana. Washington, DC: The National Academies Press. doi: 10.17226/11476.
×
  1. Engineering and design complete and construction started within 5–10 years (reduced 79 eligible features to 61 features)

  2. Sufficient scientific and engineering understanding of processes (reduced 61 eligible features to 33 features)

  3. Implementation is independent and does not require that another restoration feature be implemented first (reduced 33 eligible features to 12 features)

Several features not meeting the independence test were combined to represent interdependent packages, adding six restoration opportunities (consisting of 16 features) to the remaining 12 features for a total of 18 projects that were evaluated further (U.S. Army Corps of Engineers, 2004a). The 12 features and six restoration opportunities passing the sorting test were then evaluated by the “critical needs” criteria, which are as follows:

  1. Would implementation prevent future land loss where it is predicted to occur?

  2. Would implementation restore (or mimic) fundamentally impaired deltaic functions through river water and sediment reintroductions?

  3. Would implementation restore or preserve endangered critical geomorphic structures?

  4. Would implementation protect vital socioeconomic resources (including communities, infrastructure, business and industry, and flood protection)?

The frameworks and their component features that met one or more critical need were selected for further analysis (U.S. Army Corps of Engineers, 2004a). For example, the Mississippi River Gulf Outlet (MRGO) restoration feature met critical needs Criteria 1, 3, and 4. Seven features and five restoration opportunities (made up of 14 restoration features) met the critical needs criteria (U.S. Army Corps of Engineers, 2004a).

It is not clear how a feature was determined to meet the criteria to “protect vital socioeconomic resources” (U.S. Army Corps of Engineers, 2004a). For example, the MRGO restoration feature is characterized as protecting “developments located adjacent to MRGO” (U.S. Army Corps of Engineers, 2004a). Although at the time of this writing, it was not clear whether MRGO played a role in flooding St. Barnard Parish during Katrina, prior to Katrina various parties had speculated that MRGO might act as a major conduit for coastal storm surges that could inundate New Orleans. Though never intended to be an effort to reduce storm damage, it is not clear what protection the MRGO restoration feature would have

Suggested Citation:"5 The LCA Study Planning Approach, Modeling, and Project Selection Process." National Research Council. 2006. Drawing Louisiana's New Map: Addressing Land Loss in Coastal Louisiana. Washington, DC: The National Academies Press. doi: 10.17226/11476.
×

offered during Katrina because the proposed efforts would have taken place south and east of the levee failure responsible for the flooding of St. Bernard Parish. The Maurepas Swamp feature is characterized as protecting “the growing ecotourism industry” (U.S. Army Corps of Engineers, 2004a). How and why these projects provide vital socioeconomic characteristics are not evident. As an example, the decision to protect ecotourism rather than oil and gas infrastructure or communities in other regions is not clear. The critical needs criteria are acceptable, in principle, but the apparently ad hoc manner in which they were applied is ripe for prejudicial and political decision making and is vulnerable to future challenges.

This lengthy cost-effectiveness and sorting criteria methodology resulted in the selection of the projects termed the “plan that best meets the objectives” (U.S. Army Corps of Engineers, 2004a). This plan consists of 24 features, some of which are combined to yield 14 projects. These 14 projects are then ordered based on the time required for implementation. The top five features were selected based on funding availability. The final five projects, discussed more fully in Chapter 6, were recommended for conditional or programmatic authorization and were estimated to cost a total of $864 million (U.S. Army Corps of Engineers, 2004a). These projects are as follows:

  1. MRGO environmental restoration features ($108.3 million,5 12.5 percent of the total cost)

  2. Small diversion at Hope Canal ($70.5 million,6 8.2 percent of the total cost)

  3. Barataria Basin barrier shoreline restoration ($247.2 million,7 28.6 percent of the total cost)

  4. Small Bayou Lafourche reintroduction ($144.1 million,8 16.7 percent of the total cost)

  5. Medium diversion with dedicated dredging at Myrtle Grove ($294 million,9 34.0 percent of the total cost)

5  

USACE, in the 2005 Chief’s Report, updated the cost of the proposed MRGO feature to be $105.3 million (U.S. Army Corps of Engineers, 2005b).

6  

USACE, in the 2005 Chief’s Report, updated the cost of the small diversion at Hope Canal to be $68.6 million (U.S. Army Corps of Engineers, 2005b).

7  

USACE, in the 2005 Chief’s Report, updated the cost of the Barataria Basin shoreline restoration feature to be $242.6 million (U.S. Army Corps of Engineers, 2005b).

8  

USACE, in the 2005 Chief’s Report, updated the cost of the small Bayou Lafourche reintroduction to be $133.5 million (U.S. Army Corps of Engineers, 2005b).

9  

USACE, in the 2005 Chief’s Report, updated the cost of the medium diversion at Myrtle Grove to be $278.3 million (U.S. Army Corps of Engineers, 2005b).

Suggested Citation:"5 The LCA Study Planning Approach, Modeling, and Project Selection Process." National Research Council. 2006. Drawing Louisiana's New Map: Addressing Land Loss in Coastal Louisiana. Washington, DC: The National Academies Press. doi: 10.17226/11476.
×

Although these projects have been selected as a result of making it through a complicated set of selection processes, it remains disconcerting that the socioeconomic trade-offs inherent in rational project selection were not incorporated earlier and more formally in the selection process. If socioeconomic needs had been incorporated at the cost-effectiveness stage, it is likely that the final set of projects would have been quite different.

Furthermore, the cost-effectiveness analysis was carried out on groups of restoration features referred to as frameworks (individual features may require one or more projects to construct, while groups of features comprise restoration “frameworks”). The process began with 166 individual projects (features or measures). The project delivery team combined them into 5,670 alternatives10 based on combinations of individual projects.

The alternatives were then tested (using the IWR software) for their combinability. Out of a total of 5,670 possible combinations of alternatives, only 139 were deemed combinable. Then the 139 were tested for cost-effectiveness, and 14 emerged as nearly cost-effective; a final seven were then selected for further analysis. These seven consisted of 79 of the initial 166 projects. The 79 remaining projects were then evaluated and possibly eliminated based on considerations such as whether the engineering and design work would allow construction to begin within 5–10 years. This resulted in a final 12 projects, but some “combined features” were added for a total of 18. These 18 were then ranked based on the speed of implementation. The top five were selected based on available funding.

The project selection process primarily uses ecological benefits early on in project formulation and then uses least cost-alternatives for restoration frameworks as a filtering criteria to accept and reject frameworks and projects based upon their socioeconomic value. However, since the physical and ecological relationships between projects in a framework are not clear and frameworks optimized for cost include many projects that are not chosen for implementation, the actual role of socioeconomic factors in project selection is not clear.

Furthermore, although the cost-effectiveness analysis was carried out on frameworks, the selection decision was made for individual features. Since the cost-effectiveness was calculated for groups, there appears to be some potential for individual features that might score poorly if singled out during a cost-effectiveness analysis to be elevated by more cost-effec-

10  

An alternative is a combination of features.

Suggested Citation:"5 The LCA Study Planning Approach, Modeling, and Project Selection Process." National Research Council. 2006. Drawing Louisiana's New Map: Addressing Land Loss in Coastal Louisiana. Washington, DC: The National Academies Press. doi: 10.17226/11476.
×

tive projects in the same group. Since the selection process then breaks the groups down into individual features, it would seem more appropriate to consider the cost-effectiveness of individual features, unless the projects can be shown to be physically, ecologically, or logistically interrelated. The rational for this analysis is poorly articulated in the LCA Study, reinforcing the need for greater transparency. Obviously, if the more comprehensive approach called for in this report were used, determining the cost-effectiveness of a single project in the absence of all others would not be appropriate.

Increasing the scale of projects that have clear socioeconomic benefits, such as the protection of New Orleans, apparently was not considered. Although large compared to most CWPPRA projects, in fact, most of the features appear to be “small” projects. Since ecological and economic success might be greater or more certain with larger projects, why was the focus not on a few larger projects? Would a big initiative to save and restore barrier islands coupled with several large strategically located diversions not be more effective and informative than many “small” projects?

Planning Within a River Basin or Coastal System Context

As discussed extensively in the National Research Council’s report River Basin and Coastal System Planning within the U.S. Army Corps of Engineers:

… water resources planning and management in a river basin and coastal system context require an integrated approach to provide a balanced consideration of objectives and potential impacts at relevant time and space scales. The need for such an approach is widely endorsed by the water resources planning and management community (National Research Council, 1999a,b). [USACE] has embraced these principles and, in many cases, has played a major role in their definition and in the development of supporting methods (U.S. Army Corps of Engineers, 1999b). (National Research Council, 2004a)

A 1999 policy guidance letter defines USACE policy as a watershed approach:

[USACE] will integrate the watershed perspective into opportunities within, and among, civil works elements. Opportunities should be explored and identified where joint watershed resource management efforts can be pursued to improve the efficiency and effectiveness of the civil works programs. [USACE] will solicit participation from federal, tribal, state, and local agencies, organizations, and the local community to ensure that their interests are considered in the formulation and implementation of the effort. Due to the complexity and interrelation of sys-

Suggested Citation:"5 The LCA Study Planning Approach, Modeling, and Project Selection Process." National Research Council. 2006. Drawing Louisiana's New Map: Addressing Land Loss in Coastal Louisiana. Washington, DC: The National Academies Press. doi: 10.17226/11476.
×

tems within a watershed, an array of technical experts, stakeholders, and decision makers should be involved in the process. This involvement will provide a better understanding of the consequences of actions and activities and provide a mechanism for sound decision making when addressing the watershed resource needs, opportunities, conflicts, and trade-offs. (U.S. Army Corps of Engineers, 1999b)

As described by the National Research Council (2004a):

In this context, the term “watershed” is interpreted by [USACE] and others to indicate not only terrestrial watersheds, but also coastal systems. This connection is made explicit in other [USACE] guidance and policy documents, such as those describing the Regional Sediment Management Program (e.g., Martin, 2002; U.S. Army Corps of Engineers, 2002a,b). [USACE’s] commitment to a watershed approach is also formalized in the Unified Federal Policy for a Watershed Approach to Federal Land and Resource Management (65 Fed. Reg. 62566, October 18, 2000), which was adopted by USACE and other federal agencies. Clear support for an integrated planning approach has also been provided by [USACE] leadership. (National Research Council, 2004a)

In testimony before the U.S. Senate, Chief of Engineers Lieutenant General Robert Flowers stated:

Right now, existing laws and policies drive us to single focus, geographically limited projects where we have sponsors sharing in the cost of the study. The current approach narrows our ability to look comprehensively and sets up inter-basin disputes. It also leads to projects that solve one problem but may inadvertently create others. Frequently, we are choosing the economic solution over the environmental when we can actually have both. I believe the future is to look at watersheds first; then design projects consistent with the more comprehensive approach. (U.S. Senate, 2002)

The framework analysis that constitutes much of the project selection in the draft LCA Comprehensive Study and the LCA Study reflects an attempt to identify groups of projects that may represent least-cost alternatives for coastal restoration. In general, the emphasis placed on planning within a watershed or coastal system context is derived from concerns that interactions among the natural processes altered by water resource projects may have unforeseen and adverse consequences. It is also possible to design projects so that interactions among altered natural processes may have synergistic, beneficial effects. As discussed in greater detail in Chapter 6, the five restoration features selected and proposed in the LCA Study do not appear to reflect an attempt to optimize project selection to maximize positive synergistic effects.

Suggested Citation:"5 The LCA Study Planning Approach, Modeling, and Project Selection Process." National Research Council. 2006. Drawing Louisiana's New Map: Addressing Land Loss in Coastal Louisiana. Washington, DC: The National Academies Press. doi: 10.17226/11476.
×

THE IMPROVED MODELING AND PROJECT SELECTION PROCESS

The modelers undertook a challenging assignment to link distributed physical process models and desktop models to develop methods for determining the benefits of a diverse range of actions over a very large area. The individuals involved in the effort are to be commended for articulating the limitations of the modeling effort, as well as acknowledging the need for an S&T Program that will work to fill the knowledge gaps and quantify the performance of the LCA Study.

The process of prioritizing large groups of projects for the LCA Study is generally based on the analysis of individual small projects. With the exception of the Barataria Basin barrier shoreline restoration project, the projects are small in scope, and the end result reflects the fact that only small projects were put into the analysis process, resulting in recommendations of small projects. Serious questions are raised about the narrow vision of this project selection process to identify near-term projects when the overall philosophy has been stated as one of holistic, integrated, problem solving.

The project selection process is based primarily on measures of ecological change, such as land created, nutrient flows decreased, and species protected. This is ecologically-based management. However, some projects will have more economic value than others. Restoring wetlands that function to protect major urban areas would have more economic value than restoring wetlands that provide no such protection. The socioeconomic significance of any project is important to the rational use of resources and to its political acceptability. This dimension should be built into the project selection process earlier rather than left as a criterion filter add-on at the end. Scoring of projects based on socioeconomic significance can be done and would likely be as reliable as scoring based on expected land created or habitat units created for selected nonhuman species. This scoring would provide a rational economic input to project selection.

The draft LCA Comprehensive Study and the LCA Study make repeated references to the importance and economic value of the fisheries dependent on Louisiana wetlands. Yet, the LCA Study has not shown how the five proposed projects will, or will not, affect these valuable fisheries. Brown shrimp and white shrimp, for example, are affected differently by the shifts in salinity caused by freshwater diversions into the wetlands. However, since oysters require higher salinity than persists with freshwater diversions, the oyster culturing industry is adversely affected by some of the restoration efforts. To the extent that protection of the economic vitality of the coastal communities is an objective of the restoration

Suggested Citation:"5 The LCA Study Planning Approach, Modeling, and Project Selection Process." National Research Council. 2006. Drawing Louisiana's New Map: Addressing Land Loss in Coastal Louisiana. Washington, DC: The National Academies Press. doi: 10.17226/11476.
×

planning effort, the biological and economic consequences need to be stated explicitly.

The basic issues of coastal degradation are “sediment, sand, and salt”—too much of some, too little of others, and in the wrong places. Very broadly, the ecosystem needs protection from Gulf processes below the system and increased inputs of sediments and freshwater from above. The ecosystem needs these protections and inputs at massive ecological scales. Trying to address problems of this scale with a series of small projects is likely to make little difference relative to the scales at which ecosystem changes must occur. It is appropriate to select the small projects as a basis for learning how the system works and for helping to build the confidence necessary for large project selection. However, these small projects produce only small wetland restoration benefits. Is so little truly known about this ecosystem that it is imprudent to implement the large-scale projects that will likely be necessary to save the coast? Or are the small projects selected in order to navigate through the political obstacles that might derail efforts if focus is shifted to larger, more significant projects?

To be useful, models not only must be technically robust but must instill public confidence. Thus, it is important that the models used are defensible, accessible, and transparent so they can be used with confidence. The model codes employed should reflect widely accepted and verified approaches with a community-wide effort at model development and maintenance. The models should also utilize open-source codes with an active program of model refinement that includes quality control, consistent data sets by all users, and appropriately available and useful data. The management of data, tracking of model data sets, calibration of model parameters, and interaction and coordination of model users and developers are important aspects that should be included in the management plan. This effort should be structured to attract synergistic collaborations among modelers worldwide and to enhance the current extensive regional expertise in federal and state agencies and academia.

The project selection process primarily used ecological benefits early on in project formulation and then used least-cost alternatives for aggregates of projects (i.e., frameworks) as filtering criteria to accept and reject frameworks based on their socioeconomic value. However, since the physical and ecological relationships between projects in a framework are not clear and the frameworks selected based on cost included many projects that are not chosen for implementation, the actual role of socioeconomic factors in project selection is not clear.

For example, these criteria and the need to demonstrate solid near-term success likely resulted in the avoidance of bold innovative projects

Suggested Citation:"5 The LCA Study Planning Approach, Modeling, and Project Selection Process." National Research Council. 2006. Drawing Louisiana's New Map: Addressing Land Loss in Coastal Louisiana. Washington, DC: The National Academies Press. doi: 10.17226/11476.
×

that (1) effect a significant sediment delivery to the system, such as abandonment of the Birdsfoot Delta; (2) maximize synergistic effects for reducing land loss over longer time scales by the selection of strategically located or larger-scale projects; or (3) address some of the difficult issues associated with stakeholder response. While the efforts preceding the LCA Study achieved a laudable degree of unanimity among stakeholders on the conceptual restoration plan, this unanimity will be tested by the difficult decisions associated with implementation of the larger-scale projects necessary to achieve greater sediment, water, and nutrient delivery more effectively over a larger area. The project selection procedure requires more explicit accounting of the synergistic effects of various projects and improved transparency of project selection to sustain stakeholder support. Furthermore, beneficial, synergistic interaction among projects cannot be assumed but should be demonstrated through preconstruction analysis.

Suggested Citation:"5 The LCA Study Planning Approach, Modeling, and Project Selection Process." National Research Council. 2006. Drawing Louisiana's New Map: Addressing Land Loss in Coastal Louisiana. Washington, DC: The National Academies Press. doi: 10.17226/11476.
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During the past 50 years, coastal Louisiana has suffered catastrophic land loss due to both natural and human causes. This loss has increased storm vulnerability and amplified risks to lives, property, and economies--a fact underscored by Hurricanes Katrina and Rita. Drawing Louisiana's New Map reviews a restoration plan proposed by the U.S. Army Corps of Engineers and the State of Louisiana, finding that, although the individual projects in the study are scientifically sound, there should be more and larger scale projects that provide a comprehensive approach to addressing land loss over such a large area. More importantly, the study should be guided by a detailed map of the expected future landscape of coastal Louisiana that is developed from agreed upon goals for the region and the nation.

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