Future-Proofing Flood Risk Management

Introduction

Globally, flooding is one of the most common and destructive natural perils causing on average US$200 billion annually in damages. Many of our most densely populated areas are in coastal zones and in river catchments prone to flooding. Sea-level rise, economic development, and increased frequencies and intensities of storms will require that we continuously invest in adapting our flood risk management (FRM) systems, including flood protection infrastructure such as levees and dams and urban drainage systems. In the United States, an estimated 100,000 miles of levees can be found of which a large fraction is aging. In many cases, the reliability of these levees is unknown, and the country has yet to establish a National Levee Safety Program (NLSF). A complicating factor for FRM in the United States is that flood damage is not limited to certain areas, as one third of flood damage occurs outside of designated floodplains (Kousky and Michel-Kerjan, 2016). One of the principles that is now gaining ground in federal water resources planning and development (including flood safety) in the United States is “achieving Co-Equal Goals,” which encompasses a shift from a focus primarily on economic development to a new approach that envisions maximizing public benefits, including economic, environmental, and social goals, with appropriate consideration of costs, for present and future generations.

Adapting to a changing risk of flooding presents a major policy challenge as the upfront costs are high and immediate and the benefits in terms of flood protection are uncertain and possibly far off in the future. Traditional FRM approaches are typically a result of reactive responses to flood disasters and are biased toward quick wins driven by political pressure to “do something.” Moreover, they are often based on static assumptions about long-term probabilities aimed at optimality and economic efficiency with uncertainties implicitly accounted for through safety factors and other allowances. Mainly driven by economic development and technological innovations, these approaches often result in large-scale engineering responses. The sustainability of these infrastructure systems is currently under pressure as they are not sufficiently resilient to respond appropriately to slowly changing drivers and shocks. In addition, in the developed world, flood protection infrastructure is aging and reaching its design capacity. Although aging infrastructure poses a risk, it also provides opportunities, such as to correct old mistakes and introduce new technological and management approaches to adapt these systems to changing conditions and enhance their overall resilience.

Simultaneously, the global financial crisis has focused attention on the role of infrastructure renewal and development in economic stimulation and has reinforced government efforts to reduce expenditures. In an era of continued austerity, the challenge of governments seems to be to increase infrastructure’s capital efficiency. However, cost cutting in the near term can create increased costs in the longer term. For example, as flood defenses also attract asset investments, they can magnify flood risk if not upgraded regularly. Hence, continually investing in risk prevention is sensible as these upfront investments save money later on in terms of damage prevented.

In this article, we discuss some guiding principles that could help drive future-proofing FRM approaches in the United States, as well as the underlying pressures that create incentives for cost-effectiveness, while maximizing robustness. It is inspired by the recent Dutch history in managing flood risk, as the Dutch are setting the stage for an integrative, adaptive, and synergic approach.

Recent Developments in Dutch FRM

The Netherlands, with nearly 60% of its surface prone to flooding, is protected against coastal and river flooding by a system of 3,500 km of primary dikes, storm barriers, and dunes accompanied by 14,000 km of secondary dikes around polders and along canals. A large portion of these dikes does not meet the legal performance standards.

In 1993 and 1995, when the rivers Meuse and Rhine almost flooded, a debate was started on the limitations of our ability to control extreme events solely by technical means, that is, dike systems. This debate was fed by the scientific discourse on the reliability estimates of flood defense systems. An important issue in this debate was the challenge to properly address the uncertainties associated with economic development and climate change in these estimates. Moreover, it became clear that the huge levels of investments and their dependency on the existing defense systems in the Netherlands are so high at present date, that options for radical change are limited and in all scenarios implementation will take at least several decades. These notions prompted a reconsideration of the current FRM strategy.

As of 2008, the central government, water boards, provinces, and municipalities are working together on a new Delta Program to future-proof the country against the long-term effects of climate change. The primary goals are to provide flood safety and to ensure the availability of fresh water, now and for future generations. At the heart of the Delta Program is an integrated, risk-based approach: striving toward striking an appropriate balance between protection, prevention, and preparedness, and promoting environmental, societal, and economic gains. This new approach acknowledges that 100% protection cannot be guaranteed, that dike systems may fail, and that failure should be taken into account in the design to enhance resilience.

In 2014, the Delta Program delivered its first Delta Works comprising a pioneering and innovative multilevel governance process (Slob & Bloemen, 2014). Instead of the delivery of a major engineering system with belt and braces redundancy, it has resulted in an unprecedented organizational reform to create the time, political commitment, and institutional capacity required to explore and test innovative approaches and technologies, and to allow implementation of measures over a long time frame. It aims to create the conditions under which continual improvement and adaptation can be fostered in a learning-by-doing process. It also includes the installation of a Delta Program Commissioner who is responsible for the implementation of the Delta Program, and the establishment of a Delta Fund to ensure that funding will be available for the major investments required by the program in the long run (Deltacommissaris, 2015).

The Delta Program has a long-term vision and consists of a cohesive set of measures for the short term, medium term (up to 2050), and long term (up to 2100). This phased, adaptive approach to investment decision making was developed to incorporate major uncertainties around future conditions in the selection and design of measures. As a consequence, long-term commitments for the design and implementation of large-scale infrastructure systems have been postponed, as they create inertia and reduce flexibility for the next 50 to 100 years.

Emerging Principles for FRM

What have the Dutch learned so far? One of the lessons learned is that only by quantifying and acknowledging uncertainty are we better placed to decide how best to manage it.

Flood defense infrastructure systems implemented today will endure for several decades if not centuries. A long-term, strategic view on planning of these investments is essential to be sure that limited resources are being effectively used. The challenge is to maximize the societal benefits, including risk reduction, and minimize the costs associated with building, operating, and maintaining infrastructure at system level. In other words, infrastructure is not only about damage prevention. Infrastructure investments, such as levees, dams, and urban drainage systems, provide wider benefits for society, and current approaches of cost-benefit analysis seem to be inadequate as a tool for evaluating them. A second lesson is that a broad view on costs and benefits is crucial to unlock alternative options for funding and financing. Moreover, it is also necessary to assess and include the value of flexibility and resilience across these systems over the long term.

From the Dutch experience, the following guiding principles to future-proofing FRM approaches have emerged and could have applicability to efforts in the United States to address similar issues:

Lessons for the United States

Even though the Netherlands and the United States are vastly different in size, geography, and political systems and processes, both nations will be affected by climate change, sea-level rise, and the attendant risk of flooding. The Dutch are responding proactively and aggressively to what is recognized as a threat to the entire nation. At the heart of their efforts is a recognition that the future is uncertain and traditional approaches to FRM are no longer adequate; the technical and institutional flexibility to adapt to changing conditions will be the hallmark of future successful efforts. The guiding principles outlined above are both scalable and transferrable and could be beneficially applied to U.S. efforts at all levels of governance to successfully manage its future flood risk.