Piers are natural gathering places—they were historically built to support maritime operations, accommodate shipping vessels, manage the flow of passengers and cargo, and serve as the heart of fishing markets. Today, repurposing underutilized piers helps create vibrant waterfront spaces, attract millions of visitors and drive economies of coastal communities across North America, strengthening an area’s competitiveness as a place to live and work. 

In order to preserve the iconic value of waterfront and pier infrastructure, it is essential to integrate the appropriate flood resilience strategies into the rehabilitation of industrial urban harbor areas. 

The Port of San Francisco’s Elaine Forbes agrees: “Today, more than 24 million visitors come to San Francisco’s waterfront each year. It’s important to focus on adaptive resilience measures that we can implement now to maintain the viability of the historic piers without altering their character.” 

Sea level rise threatens the vitality of piers and waterfronts

Climate change is already increasing pressure on coastal cities. By the end of the century, low-lying coastal cities will face projected sea level rise by as much as six feet. Urban waterfronts and piers are also becoming progressively vulnerable to extreme weather events such as stronger hurricanes, heavier rainstorms and more severe flooding. 

Sea level rise and flooding can do more harm than physical infrastructure damages. Cities must also consider the additional interdependencies such as disruption of business continuity from temporary closure of the pier facilities.

Reshaping underutilized urban harbor areas into flexible, mixed-use developments is the perfect opportunity to prepare for climate change while creating vibrant waterfront spaces. Integrating flood protection measures into pier restoration projects using a systemic approach allows cities to preserve history while mitigating risk. 

Identify flood resilience strategies to protect piers 

Based on my experiences identifying flood risk mitigation strategies to protect piers, I've identified key steps every plan must take: 

• Understand the goals of the city and the community. What are the city’s resilience objectives? What are short-term and long-term goals? What value does the community place on the piers and waterfront and how can it enhance community uses? What are the funding options?


• Utilize data to quantitatively define and measure flood risk mitigation targets. Evaluate current and projected flood risk. Recognize that several factors affect current and future flood risk and develop use cases to account for variations. For example, the pace and severity of sea level rise depends on the pace and scale of global greenhouse gas emissions as well as the success of subsequent reduction efforts, which will impact floodproofing measures.


• Consider additional sustainable design aspects. Improving pier resilience is an excellent opportunity to assess the local sustainability potential. For example, is it a viable option to add a renewable energy generation component when rehabilitating the pier infrastructure?


• Identify a range of flood risk mitigation measures. Based on the goals and data, develop a number of flood risk mitigation strategies that can be implemented separately or used in conjunction. In our work with the Port of San Francisco, we identified five adaptive and two supplemental flood risk mitigation measures. These adaptive measures are intended to protect the existing structures against flood risk over a substantial portion of this century, while minimizing the transformation of the structure itself, and therefore minimizing potential impacts to the historic district and limiting the capital costs necessary to implement such measures.


• Test, test, test. Assess the feasibility and technical suitability of solutions by evaluating the strategies from multiple perspectives, including: level of acceptance among the various stakeholders; engineering design considerations; depth of flooding above the pier deck the measure is able to protect against; constructability, permitting, maritime and below deck maintenance considerations; operations and maintenance impacts; architectural or historic preservation and capital costs. 

Although resilience is often framed within the context of disaster or distress, at Arcadis we believe that a comprehensive approach to resilience planning is key to finding the right solutions that benefit citizens, business leaders, shareholders and stakeholders alike. See more in our business case for resilience insight.