BATON ROUGE, La. (July 25, 2018) – As subsidence, sea level rise, and increasingly intense rainfall continue to challenge New Orleans, understanding what is going on underneath the city becomes vital.
In an effort to improve the city’s resilience, the U.S. Department of Housing and Urban Development granted The City of New Orleans $141.3 million in National Disaster Resilience Competition (NDRC) funds for its Gentilly Resilience District plan to create a replicable model of urban resilience and water management. The City’s Office of Resilience and Sustainability is partnering with Deltares and Deltares USA Inc. to assist with development of the plans, as well as implementation of many of the plan’s scientific and technical components.
New Orleans subsides by an average of 6 to 8 mm a year and a large part of the city is already below sea level. The City of New Orleans NDRC proposal – “Reshaping the Urban Delta” – aims to guide New Orleans on the path of becoming a resilient city that is better able to cope with water and land-subsidence challenges. The work will begin with an 18-month analysis and modeling done through collaboration between Deltares, The Water Institute of the Gulf, and Tulane University to focus on the New Orleans subsurface. The aim is to ensure that rainwater, surface water, groundwater and land subsidence in the urban area can be managed in a coordinated way. This analysis will inform the design and management of green infrastructure projects funded in the Gentilly Resilience District and guide ongoing urban water planning throughout the city.
“This new work builds on the resilience strategy New Orleans launched in 2015 and an understanding of the best available science on future challenges,” said Ehab Meselhe, Ph.D., Vice President for Engineering at the Institute, a professor at Tulane University’s River-Coastal Science and Engineering Department, and the Institute’s project lead. “Knowing how water flows through and under the city is vital in the overall plan of how New Orleans learns to live with, and adapt to, water.”
The first step will be analyzing current subsidence and water flows under and around the city and to look at expectations for future climate change, sea level rise and subsidence impacts. This analysis will be made on the basis of 63 soil drilling operations around the city.
“You can't manage what you don't know. You can't see the subsurface. If you lack knowledge about the system – and that knowledge has been sparse until now – you can't know how groundwater and surface water respond to interventions or to climate change,” said Roelof Stuurman, technical project leader and groundwater expert at Deltares. “I'm proud of the focus on the subsurface in this project. The subsurface is associated with threats such as land subsidence but it also offers opportunities for storing water, for example in rain gardens.”
In addition, specifications for measuring instruments will be drawn up and a database will be established for measurement data. Finally, work is taking place on a numerical groundwater/soil subsidence model, which will be followed by the design and installation of an integrated water monitoring network. The result will be New Orleans’ first ever groundwater monitoring network to provide decisionmakers with information necessary to set data-based priorities to maximize impacts.
Once the subsurface has been charted and the status quo established, researchers will be able to test the impact of possible and planned solutions such as water-permeable streets and gardens used to store water. Finally, a study will be done to examine the feasibility and opportunities for a “real-time” automated pumping system that would be based on weather forecast.
The project’s development will include input from agencies, the city and local residents and will show what can be done at different scales, from private land to the district levels, to reduce land subsidence and floods, and to support the city policy and the Sewage and Water Board of New Orleans.
Link to photos and cutlines here.
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About The Water Institute of the Gulf
The Water Institute of the Gulf is a not-for-profit, independent research and technical services resource with a mission to support resilient coasts and sustainable water systems worldwide. Our work helps ensure livable communities and a thriving economy and environment. For more information, visit www.thewaterinstitute.org.
About Deltares
Deltares is an independent institute for applied research in the field of water and subsurface. Throughout the world, Deltares works on smart solutions, innovations and applications for people, environment and society. The main focus is on deltas, coastal regions and river basins. Managing these densely populated and vulnerable areas is complex, which is why Deltares works closely with governments, businesses, other research institutes and universities at home and abroad. For more information, visit https://www.deltares.nl/en/.