Chapter IV

Improvements to Technical Mitigation

This section covers improvements to technical mitigation projects. Technical mitigation is defined here as the suite of coastal flood mitigation options including structural elements such as walls, levees, and gates, etc., and nature-based elements such as beach nourishment, shoreline stabilization, etc. This definition is based on U.S. Army Corps of Engineers (USACE) activities outlined in their Planning Guidance Notebook. 87

Despite improvements to the NFIP and changes in zoning laws and building codes, there are many coastal areas across the US that will remain vulnerable to flooding or will become vulnerable in the future. A recent study estimates that cities like Miami, New York, New Orleans, and others across the US will see significant increases in flood risk by the year 2050, even assuming proper adaptation measures are taken to keep flood probability constant. 88 This study finds increasing risk is primarily driven by increasing exposure due to coastal development. Other studies have found that increases in coastal flood risk will occur due to sea level rise 89 and changes in extreme weather and storm climatology. 90 Addressing changes in future hazard and exposure will require strategic investment in coastal flood defenses that protects valuable commercial infrastructure and communities located near the coast.

The majority of large-scale technical mitigation projects are implemented in coordination with USACE and a non-federal partner, such as a state or local agency. Initially, the local/state entity submits a request for assistance. USACE then conducts a reconnaissance study to determine the scope and severity of the flood project. This is followed by a full feasibility study that evaluates potential plans and ends with a project recommendation. The evaluation and selection of the recommended project plan is based on maximizing “net economic benefits”. 91 If a suitable plan is found, the project is sent for congressional approval, and ultimately Congress can appropriate funds for the project’s implementation. However, even if a project is authorized by Congress, it may not necessarily receive funds for construction. There is a backlog of hundreds of approved projects that have not received funds yet, and these projects total $60 billion in federal funding requests. 92

Problem Definition

Finding 1

The backlog of funding for USACE projects has delayed many infrastructure projects that were designed to mitigate flood risk. In some cases, these projects are so delayed that their implementation today may not provide the benefits that were initially intended.

Recommendation 4.A: Address Equity Concerns Regarding the USACE BenefitCost Analysis (BCA) In addition to the current backlog of approved projects, there are several other areas for potential improvement with regard to the evaluation, coordination, and implementation of technical flood mitigation projects. We highlight three additional findings from our investigation below.

Finding 2

Current cost-benefit analysis methodology used by USACE can result in inequitable allocation of resources to vulnerable communities.

Finding 3

Although in recent years USACE has strived to incorporate the impacts of sea level rise in their project evaluation framework, there is need for greater consideration of changes in coastal extreme rainfall and more emphasis on anticipatory planning for projects in high-consequence regions.

Finding 4

Improvements to USACE’s administrative framework, specifically regarding integration with other federal agencies and coordination with local/state agencies could improve the effectiveness of flood reduction activities.

During the feasibility study phase of a potential project, USACE conducts a benefit-cost analysis in order to determine the net economic benefits of each proposed solution and evaluate whether the project is worthwhile to pursue. Benefits are calculated based on both direct damages avoided (physical damages to buildings and infrastructure) and indirect damages avoided (such as those resulting from emergency response to floods or loss of income/economic activity due to flooding). 93 In particular, this analysis focuses on national benefits, rather than local or regional benefits of the project. A study that conducted interviews with practicing engineers found that they indicated frustration with the emphasis on national benefits rather than local safety that resulted from the current USACE BCA. 94 The emphasis on national benefits is also perceived as unfair, since communities provide a large amount of funding for the project through the cost-share agreement, but ultimately the selected plan maximizes national benefits rather than benefits to the specific community. 95 Additionally, focusing on average annual damages avoided as the primary benefit metric penalizes lower income communities where both property prices and economic

activity are depressed. Perversely, these are the areas where technical mitigation may be most needed, 96 since residents may not have flood insurance due to affordability issues and structures are unlikely to be equipped with flood-proofing measures. During a trip to Louisiana while researching this topic, several local and state agencies mentioned this equity issue as a major challenge inhibiting coordination with USACE, stating that many projects that would provide community benefits would not pass the benefit-cost ratio stipulated by the Corps.

At the state level, there have been efforts to address these equity concerns by moving away from the traditional method of BCA. In Louisiana the Coastal Master Plan is an aggregation of coastal flood reduction and restoration projects that prioritizes projects based on either square miles of restored land or reduction in average annual damages. 97 Although this initiative still relies on average annual damages like the USACE’s methods, it does not require a benefit-cost ratio (BCR) greater than 1 for a project to be deemed viable.

In the literature other methods have been proposed to more effectively take into account income distribution when evaluating flood mitigation projects. One such example is the use of equity weights, which weigh benefits in lower income areas higher to produce equity-weighted expected annual damages (EWEAD). 98 Alternatively, a risk premium could be introduced that varies progressively with the fraction of household income lost in a flood event. Thus, areas where a higher percentage of household income is expected to be lost in a flood event would have a higher risk premium. This produces “certainty equivalent” expected annual damages 99 as the primary benefit metric.

USACE should commission a study to evaluate the use of alternate benefit metrics for projects that would protect underserved communities. This study should evaluate whether equityweighted or other social vulnerability metrics could be incorporated in the analysis and assess what types of communities should be eligible for consideration under alternate metrics. This study could be done in conjunction with HUD through the NEHRP framework.

USACE should develop an alternate application process for flood mitigation projects targeting socially vulnerable areas. USACE could allow a separate process for smaller projects that would provide flood reduction to under-served communities.

Study on Alternate Benefits

Alternate Application Process

In recent years the USACE has made significant efforts to incorporate the impacts of future sea level rise (SLR) in their project evaluation and decision-making process. Updated policies require all coastal flood reduction projects to consider future changes in sea level in the plan formulation phase, evaluation phase, to aid in decision-making, and to help craft long-term maintenance schedules for proposed projects. 100 In particular, sea level rise is considered by examining three future potential scenarios: a low scenario, medium scenario, and high scenario. The low scenario is based on a simple calculation of historical rates of sea level rise at the study area, while the medium and high scenarios are set by the National Research Council. Ultimately, a plan is chosen that maximizes net economic benefits while ideally being adaptable to future SLR. Plans can be selected that are reactive, adaptive, or precautionary. Reactive strategies are implemented after a major flood disaster, while adaptive strategies are implemented at various points during the project lifetime to adapt to observed changes in the environment, and precautionary strategies implement designs upfront that anticipate certain future conditions. USACE typically emphasizes the adaptive approach, and project plans can delineate future maintenance and update schedules.

Recommendation 4.B: Continued and Expanded Considertation on Climate Change

Precautionary Approaches

Fast-track Implementation

Synthesize Studies on Climate Impacts

While this planning process works well in cases where the baseline (low) scenario already results in a viable BCR for a potential project, it is more challenging to deal with situations where the present-day BCR is less than one, but under future medium/high scenarios the BCR is greater than one. This situation was outlined in a recent study 101 which evaluated a suite of structural and non-structural coastal flood projects for New York City. Structural solutions were only economically attractive under a future medium or high climate change scenario, and consequently the authors suggested delaying investment by 25 years. Ideally, this type of long-term scheduling of investment would produce the most favorable outcomes. In reality, the large backlog of projects and the difficulty in securing federal funds for a project many years in advance make adaptive strategies difficult to realize. Therefore, it may be worthwhile for USACE to consider a riskaverse precautionary strategy for some high-consequence areas like large coastal cities.

USACE should delineate clearly where precautionary approaches for project planning are appropriate and where adaptive approaches are viable. It may be worthwhile to begin constructing a project that has a BCR less than one now, if the project would provide high levels of protection under future scenarios. This ensures that flood defense projects can be authorized at times when there is increased political will instead of trusting that they will be implemented at the right time at some point in the future.

USACE should develop procedures for fast-tracking implementation of adaptations to current flood defenses. Proposals to upgrade existing infrastructure could be passed through a streamlined evaluation process so that adaptations can be implemented in an efficient and timely way.

In addition to the advancements made in considering SLR, there should be expanded consideration of climate change to include changes in extreme rainfall at the coast. Numerous recent studies have suggested that TC rainfall is becoming more severe due to climate change. 102, 103, 104, 105 Traditionally, coastal flood hazard assessment has focused almost exclusively on storm surge. However, recent events suggest that extreme rainfall can also result in widespread flooding in coastal communities.

Currently, USACE offers guidance about incorporating climate impacts for inland hydrology projects, 106 but no such guidance exists for coastal areas subject to both storm surge and extreme rainfall. USACE should synthesize all relevant studies related to climate impacts on coastal extreme rainfall and summarize findings within a single technical document. This document should draw on work being conducted within NOAA and USGS in order to produce cross-departmental guidance as a first step in understanding current knowledge about future rainfall hazard and the extent to which coastal rainfall should be considered in hazard analysis. This preliminary guidance could be non-binding and could primarily serve as a foundation to begin considering the risks associated with coastal rainfall.

Recommendation 4.C: Improvements to USCACE Administrative Framework A review of USACE’s administrative framework in coastal flood risk control shows that powerful cross-agency coordination is lacking at both the federal and local levels. This coordination failure produces three consequences: (1) a disparate levee system safety evaluation principle that prompts perverse incentives for infrastructure sponsors in risk management, reducing preparedness for future flood risks; (2) a lack of strong leadership sub-nationally, which prevents consensus building from key stakeholders on crucial policy topics, fragments management, and slows down project implementation; and, (3) limited

support for USACE’s local coordination platform (the Silver Jacket Program), which failed to motivate innovations in local management or utilize local talents and information.

First, the two de facto levee safety evaluation standards adopted by USACE and FEMA may invite regulation-shopping practice by non-federal project owners and reduce overall safety. Levee safety evaluation, a key component in the levee system accreditation process, determines whether an area in question behind the levee meets FEMA’s hundred-year flood prerequisite; accreditation makes the area eligible for benefits within the NFIP. 107 In the aftermath of Hurricane Katrina, USACE has made its evaluation stricter, adopting risk-informed and probabilistic approaches. 108 By contrast, FEMA accreditation principles remain based on deterministic models informed by historical events. 109 Given the geographical complexity and changing climatology across the country, the hundred-year flood threshold only amounts to a minimal standard. According to USACE, a comprehensive evaluation report not only improves predictions, but also communicates a better perception of risks to stakeholders, enhancing safety systematically.

However, more rigorous practice is wanting. On one hand, USACE only offers evaluation service to projects under its own purview; on the other hand, FEMA allows private levee certification for non-federal sponsors. The USACE’s small project evaluation expenditure 110 suggests a low utilization of its “stricter” evaluation process and the prevalence of minimal safety standards within the system. Moreover, best practices could be used less frequently in the future. The Corps’ 2014 levee inventory shows that projects directly managed by USACE account for the smallest portion of total projects. 111 It is likely that locally owned projects, those confirming to the looser certification standards, will become a larger potion of the total levee stock given public funding uncertainty.

Strategic planning at the state level often suffers from weak collective leadership, yet USACE’s low visibility in planning process contributes to this problem. Though the Corps introduced early coordination in infrastructure projects in 2014, 112 its engagement efforts in nonstructural planning has varied. Literature produced by the USACE on indicate that participation is invite-based. This laid-back engagement approach prevents agreement on policy goals, which is particularly detrimental to flood mitigation planning since success is predicated on strong alignment among planners and buy-in from community stakeholders. The New York Oakwood Beachwood buyout project post-Sandy offers a negative case in point—multiple agencies operated under respective mandates without agreeing on or even clarifying the end-goal of a proposal. The USACE was working to finalize a levee construction plan while New York state was promoting buyout in the residential areas behind the purported infrastructure. Conflicting, contradictory initiatives stirred confusion among community members andcity officials who wondered if the goal was managed retreat or infrastructure hardening. Such uncertainty further complicated, if not directly disrupted, the already fragile buyout process. Ultimately, the proposed vacancy turned out to be part of the Corps’ planned drainage system, under informal co-development with the state. 113 In addition to weak leadership, the Corp’s flagship local coordination initiative, the Silver Jackets Program, failed to generate enthusiasm. This program aims to encourage non-structural flood risk mitigation by empowering local leads to utilize resources from multiple agencies. However, despite fast initial enrollment, the total number of projects only reached 280 from 2011 to 2017, with each participating state barely receiving one project. 114 Resource constraints are potentially the culprit. First, the program is not a grant; instead, “expense” occurs primarily to purchase expertise within the organization, somewhat limiting the scope of project design. Second, the program has no designated shared resources across partners such as a joint funding pool or staff who can make executive

Waterfront park in Loiza, Puerto Rico eroding in spite of a sea-wall built by USACE.

Credit: Juan Pablo Ponce de León

Levee System Accreditation Standards

Community Outreach

decisions. As a result, each agency’s support comes out of pocket separately. Fragmented information and administrative frameworks only increase management costs for project planners. Third, it is likely that the already small allotment will be further cut—shown in the Corps’ 2020 budget, the Flood Control and Coastal Emergencies (FCCE), which houses the majority of non-structural programs, has dropped to $27,000 for FY2020 from $35,000 in FY 2018 and FY2019, an over 20% cut. 115

The federal government should direct USACE and FEMA to work towards reconciling levee system accreditation standards. The dual-standard system may create perverse incentives for project sponsors and reduce best practices in the flood risk control system. It is understandable for FEMA to keep minimal standards for practical concerns in the near term. The two agencies should move away from merely recognizing each other and begin to contemplate merging their functions.

USACE should enhance its communicative outreach at local levels. This recommendation is two-pronged. First, the Corps’ participation should be institutionalized at strategic planning meetings, and not optional, particularly in cases that involve USACE’s existing project or projects in pipeline. Second, the Silver Jacket program needs a series of structural changes, including creating a cross-agency permanent funding pool, assigning a desig

nated manager to preside over joint resources, and allowing small discretionary spending on a per-project basis.

USACE should increase ringfence funding for the two aforementioned purposes, whose success also predicates on firm material support. The funding volume may not need be large, partly because of macro-level fiscal constraints, and partly because it will be seeding programs purported to create momentum. However, these ideas, despite their strategic value, are highly prone to budgetary cuts, a process which favors programs with vested longstanding constituencies. Therefore, it is important to make these accounts cut-robust, for instance, by imposing a percentage rate on overall budget or programmatic expenditures.

Takeaway 1

There is an increasing need for continued technical mitigation projects as the effects of climate change worsen and projections change, but improvements to current USACE procedures are needed to more quickly, efficiently, and equitably implement flood hazard mitigation projects.

Ringfence Funding

Conclusion

Takeaway 2

USACE should either incorporate equity weights or alternative risk premiums to improve measures of benefits provided by technical mitigation projects. USACE could also commission a study on alternative benefit metrics or consider an alternative application process that incorporates considerations of social vulnerability.

Takeaway 3

USACE should consider a risk-averse precautionary strategy for considering the impacts of climate change and sea level rise in high-consequence areas like large coastal cities. Higher weight and faster implementation timelines could be placed on projects that provide substantial future benefits. USACE also should synthesize all relevant studies related to climate impacts on coastal extreme rainfall and summarize findings within a single technical document.

Takeaway 4

There is room for USACE to enhance management integration horizontally across the agency as well as vertically amongst subnational stakeholders. To incentivize best practices within the system, Congress should direct the Army Corps and FEMA to work towards reconciling levee system accreditation standards, direct Army Corps to enhance communicative outreach to local governments, and ringfence funding for the two aforementioned purpose.