Resilient Design Resource Kits

Mitigating Floods & Sea-Level Rise

NEEDS STATEMENT:
WHAT’S THE PROBLEM AND WHY DO WE CARE?

Flooding is the most frequently occurring natural disaster globally. Flooding-related natural disasters have displaced tens of millions of people in the last ten years, claiming hundreds of thousands of lives globally. Human settlements have always been at risk of flooding, but climate change, the expansion of cities, and their location of poorer human settlements, means floods are driving impacts up, with greater human and economic costs associated with each event. In densely-populated urban areas, massive expanses of impervious surfaces, including roofs, asphalt streets, parking lots, and concrete structures inhibit water filtration and exasperate runoff problems. Excess water flows, problematized by accumulated debris and pollution that blocks and overwhelms sewer and stormwater management systems that cannot handle such volume, greatly impair water quality.

Common causes of flooding include tidal events, storm surges, heavy rain, and sea-level rise. Extreme flooding causes catastrophic and irreversible environmental damage to the Gulf of Mexico, and regularly costs gulf states, like Louisiana, billions of dollars in damages annually. Increasingly frequent superstorms, like Hurricane Sandy (2012), cost the Northeastern US $71 billion in damages. Sea-level rise and storm surges create coastal resiliency challenges that salinate aquifers to threaten drinking water reserves for millions. These are all irretractable changes facing coastal communities.

TAKING A SYSTEMS-BASED APPROACH TO BUILDING INTEGRATED KNOWLEDGE

Flooding is a highly local problem: there are inland and coastal floods; floods caused by storms or sea level rise; floods caused by groundwater or sea water; and floods that have multiple causes, so solutions must be designed for particular conditions. Integrated science and design collaborations can work together to develop multi-use systems that can serve as public spaces and flood mitigation solutions.

Visualizations of data sets can aid in a better understanding of topography, hydrology, and ecology to create systems that divert, absorb, and capture water. Extensive community surveys and information gleaned by municipal-level interactions can be synthesized to provide policy insight, and offer communities solutions for retaining cultural resilience in the face of long-term loss. Landscape architects, planners, ecologists, engineers, architects, policy advisors, environmental lawyers, economists, environmental psychologists, communications experts, coastal resiliency science teams and local stakeholders join together to plan, design and implement these systems.

WII has joined with Virginia Sea Grant to provide academic reviews of team science resiliency proposals designed to aid communities vulnerable to sea-level rise on Virginia’s Eastern Shore. WII is also collaborating to explore ecological, economic, social, policy and engineering/infrastructure issues relating to coastal resilience in Louisiana and Virginia.

POTENTIAL IMPACTS, VALUE, AND OUTCOMES

Preserving and restoring threatened ecosystems to prevent and mitigate flooding, means preserving biodiversity, forest cover and green space. Greener designs for moving water during floods, such as parks, offer recreational spaces that boost public health. In addition to absorbing water, green infrastructure cleans and cools the air, mitigates erosion, increases water quality, and recharges water tables.

For those living in floodplains or on the oceanfront, traditional water mitigation techniques include building expensive sea walls or levees, or raising homes onto stilts. However, these mitigation methods are at risk of catastrophic failure, and rebuilding is costly. Better environmental design can help communities live with flooding in the short term, however, the large-scale implementation of green infrastructure is nascent as an applied field, and in and of itself, needs critical evaluation. With climate change, many communities will eventually be forced to relocate. Systems-based approaches can be used to develop green infrastructure for municipal-level master plans, to strengthen coastal ecosystem resiliency, and create natural barriers, channels and buffers that can buy communities time. Holistic and robust green infrastructure systems, including those for transportation networks, parks, and ecologically engineered stormwater management, can more safely divert or hold water, clean and absorb flood waters, and enable communities to more effectively live with more extreme water events.