Reducing Our Risk

Waggonner & Ball Architects

Entry Overview

Survival on the Mississippi River Delta requires constant awareness of the forces of water, with “multiple lines of defense” to protect against high water in the Mississippi, hurricanes approaching from the Gulf of Mexico, and intense rainfall due to a sub-tropical climate. The federal levees and floodwalls at the project area’s perimeter protect human settlement from high river waters and hurricane storm surges. Within the levees, complex systems of canals, pipes, and pumps protect against flooding caused by rainfall. These systems are inadequate to the challenges posed by a changing urban landscape and climate, and are the primary cause of subsidence in the region. The Greater New Orleans Urban Water Plan (The Plan) focuses on water within the levees—primarily stormwater, surface waters, and groundwater—and a new approach to managing these resources. It outlines principles for water management, regional planning, and urban design that are specific to this region, developed out of a process that considers 1) the region’s soils, water, and biodiversity, 2) existing infrastructure networks, and 3) the urban fabric. 

General Info
Email :
Organization Address: 
2200 Prytania Street
New Orleans, Louisiana 70130
United States
Population Impacted: 
Identify the likelihood and frequency of this hazard : 
Heavy flooding occurs in the city during a “10 year storm,” one defined as having a 10% chance of occurring in any year (these storms actually occur approximately four times each year). 10 year storms and 100 year storms have similar amounts of rainfall, so reducing flooding for a 10 year storm would also reduce the impact of larger storms. These storms, along with droughts during dry times, are increasingly taxing the system.
Explain how vulnerable the community is to this hazard: 
Intense rain storms indiscriminately affect businesses, homeowners, public spaces, and vital infrastructure such as roads. In addition, subsidence, the decomposition and shrinking of highly organic soils through excess drainage, causes damages to buildings and infrastructure while increasing flood risk. Overtime, subsidence disrupts the foundation for the hurricane protection system, putting hundreds of thousands of lives at risk during hurricane events. Flooding and subsidence are New Orleans’ existential threats in the 21st century.
List the potential affects of this hazard: 
Overtime, subsidence, coastal erosion, and increased frequency and intensity of storms will make living in New Orleans and the Mississippi River Delta, a rich place of cultural and economic exchange, more and more difficult, having incalculable impacts on citizens of not only New Orleans, but throughout the United States. Projections modeled by the design team indicate that rainfall-induced flooding and subsidence will cost Greater New Orleans an estimated $10.2 billion over the next 50 years.
Identify how sensitive the community is to these affects: 
Residents of the New Orleans region have been aware of the risk of flooding for hundreds of years and accept it as part of life. The traditional solution to this problem has been to create hard, buried infrastructure that removed the water from the city as quickly as possible, keeping it out-of-sight and out-of-mind. Climate change and subsidence require a new paradigm for stormwater management that works with the water to increase safety and sustainability.
Preparedness Goal: 
We created an actionable plan to reduce a billion dollar flooding and subsidence problem through green infrastructure.
Implementing Actions: 

The Plan is composed of 3 main volumes and 26 supporting reports, all of which are publicly available for download at The Vision volume provides an overview of the project, and summarizes the project’s conceptual underpinnings, key findings, planning and system design proposals, and implementation strategies. The Urban Design volume is geared towards planning and design professionals, and presents water planning principles through design drawings at the system, basin, district, and demonstration project scales. The Implementation volume is geared towards policy-makers, water system managers, and other stakeholders, and it outlines an action plan that includes prioritization and phasing of proposed strategies, financing tools, policy and community action recommendations, and a consideration of existing jurisdictions and potential partnerships. The supporting reports are organized into four categories: 1) system design & analysis, 2) demonstration projects, 3) design districts & urban opportunities, and 4) resources & urban analysis.

The extensive outreach process outlined previously has also built a diverse group of committed stakeholders, ranging from GNO, Inc. on the economic development side to the Horizon Initiative Water Committee, which brings together stakeholders at monthly meetings. Today, community engagement continues through an evolving website, iPad app, and multiple forms of face-to-face engagement such as the Ripple Effect, an organization which works with teachers to integrate urban water issues into school curricula. Continuing outreach and distribution of materials to parish leadership, stakeholders, and community groups, along with workshops on subsidence and other water-related topics further builds the stakeholder group committed to implementing the plan. Progress on demonstration projects will serve as a tangible mark of advancement and provide opportunities to test innovations in technology, design, and implementation. 

Describe Your Solution: 

The abundance of water, wetlands, and waterways in the Mississippi River Delta is a distinct regional advantage. Over three centuries, however, Greater New Orleans has reshaped itself with an approach to drainage and flood mitigation that pushes its water assets out of sight and out of mind. Long-term resilience requires adapting this approach and existing water management systems.  In the Greater New Orleans of tomorrow, stormwater, surface water, and groundwater are managed together, as resources with which to enhance public spaces, revitalize neighborhoods, strengthen habitats, and provide opportunities for economic growth. In finding the means to thrive in a place of economic and cultural importance—but also one of weak soils and ecological instability—Greater New Orleans can become a world leader in climate-adaptive design and water resource management.

In 2010, the State of Louisiana’s Office of Community Development funded the development of the Greater New Orleans Urban Water Plan, a vision for urban water management that integrates infrastructure planning and urban design, while addressing the problems of pluvial flooding, subsidence, and the misuse of regional water resources. It proposes a new investment model for public works, wherein spending on streets, canals, pump stations, and stormwater detention basins enhances the public spaces that are so vital to life in the region, and yields opportunities for economic growth and development. Proposed retrofits strengthen existing water systems, make use of undervalued water assets, enhance key corridors, and broaden the hurricane protection concept of “multiple lines of defense” to include urban water management. The plan provides a science-, engineering-, and design-based approach to transforming existing drainage systems and the urban landscape using proven strategies and technologies, as well as insights in planning and design developed through the Dutch Dialogues workshops and Urban Water Plan process.  


The Plan was the basis for City of New Orleans’ successful bid to become one of 8 Rockefeller RE:invest Initiative cities, which provides the city with over $2 million in funding and technical support in financing and implementing green infrastructure. Additionally, the plan is spurring the growth of water-based industries and resiliency planning as key growth sectors for southeast Louisiana, and drawing national attention to Greater New Orleans as an example of innovative regional planning and design.


Pumping water out of New Orleans after a rain storm is an incredible feat, and also very energy intensive. The Plan proposes natural strategies that alleviate loads on drainage systems, reducing the costs and detrimental side effects associated with their operation. Green roofs, bioswales, permeable pavement, etc. greatly reduce energy use and improve water quality. Moreover, green interventions cool the air, reducing dependence on air conditioning. All of these tactics achieve valuable secondary benefits while serving their primary purpose to slow down and store water to reduce flooding and subsidence.


Today, communities are disconnected by existing water infrastructure. For example, canal walls create impasses that separate communities, economic activity, and people. The Plan directly addresses connectivity in its proposal to remove flood walls, creating corridors of water and greenery that invite neighborhood interaction, economic activity, and recreation. The Plan proposes dual-purposing under-utilized public lands, making them both storage for excess stormwater and spaces for gardening, agriculture, and meeting during dry times, often taking advantage of vacant lots to achieve these goals. Lastly, the plan proposes investment across the city, focusing resources and thought on areas that have traditionally been overlooked.  

What were the negative or unintended impacts (if any) associated with implementing this solution? : 

The timeline for full implementation we propose in The Plan is 50 years. This can cause impatience and perhaps a loss of faith, ultimately resulting in a more difficult path to realization. Additionally, depending on the rate of climate change going forward, the systems may not be adequate or require retrofitting after the 50 year mark. The $6.2 Billion cost of the plan saves billions over the long run, but is a steep cost for the resources available today. Paying for the plan requires a significant shift in mindset, policy, and creative funding strategies. Other hurdles to full implementation include capacity, commitment, resources, and continuity. For example, critical tasks like the monitoring of subsidence and groundwater must become someone’s responsibility. This requires dedicated resources and will.

The plan was conceived of as an interconnected system. If future political or planning administrations only choose to implement select parts without consideration for their interconnectivity, the proposed solution may not work as well, or at all. Thus, if moving forward, it is necessary to have resources for proper sequencing of implementation.

Return on Investment: How much did it cost to implement these activities? How do your results above compare to this investment?: 

The Plan covers a three-basin project area of approximately 225 square miles including 70 square miles of protected wetlands. The plan proposes two levels of implementation: the basic level comprises urban design interventions that can be completed most easily within the current economic and political framework at a cost of $2.9 Billion. Full implementation of the Plan is estimated at $6.2 Billion over the next 50 years, with an estimated economic benefit of $22.3 Billion.

When considering both the cost and benefits of implementing The Plan, it is important to remember that the cost of doing nothing is not free. Rainfall-induced flooding and subsidence will cost Greater New Orleans an estimated $10.2 billion over the next 50 years. The plan proactively addresses these issues to avoid these costs.

The benefit calculations were based on estimation of the value of job creation, reduced flooding, reduced subsidence, lower flood insurance premiums, and increased property values. 

What are the main factors needed to successfully replicate this solution elsewhere?: 

The layered planning approach that undergirds every aspect of the Urban Water Plan process is replicable in communities across the U.S. Climate change and natural disasters serve as constant reminders of the importance of understanding the geological, hydrological, and ecological context within which each community is situated. In the Mississippi River Delta and other deltaic environments, soil and water management pose particularly difficult challenges, and The Plan provides both a methodology and prototypical planning and design solutions with which to address those challenges. The Urban Water Plan team is a member of the Connecting Delta Cities collaborative, an international effort to foster shared knowledge, and team members have or are now contributing expertise gained through the Urban Water Plan process to regions as diverse as Lafourche Parish on the Louisiana coast to the Eastern Seaboard as it continues to recover from Hurricane Sandy.    

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Contest Name: 
Reducing Our Risk

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