How can planning projects address regional or watershed issues that benefit individual municipalities?
The Greater New Orleans Urban Water Plan addresses the systematic water resource management issues of communities in St. Bernard Parish and on the East Bank of the Mississippi River in Jefferson and Orleans Parishes. The heavily urbanized neighborhoods of Orleans, Jefferson, and St. Bernard Parishes are encircled by levees to protect from river and storm surge flooding, but even with a few inches of rain, water floods some streets. Heavier rains can lead to flooding of buildings and extremely dangerous road conditions, despite the large-scale pumping infrastructure and network of canals. This regiment of draining to canals and pumping has led to significant rates of subsidence in parts of the subject area leading to greater vulnerability to flooding as well as building and infrastructure decay. To complicate matters, stormwater management, flood protection responsibilities, and water pipe maintenance are divided among a number of agencies at the local, parish, state, and federal levels.
Greater New Orleans, Inc., a non-profit economic development alliance, directed this multi-parish planning effort with a consultant team of designers, engineers, scientists, and policy experts led by Waggonner & Ball Architects. The Greater New Orleans Urban Water Plan team worked closely with local governments during plan development, though the implementation of the plan will be the responsibility of the communities.
The major goals of the project include increasing safety, providing economic opportunity, and improving quality of life. The project aims to address flooding and subsidence by intervening at different scales of community – the ground (soil, groundwater, vegetation), infrastructure networks (sewer and water systems, roads, utilities), structures (homes, schools, businesses), and people.
Resilience Planning in Action
The Greater New Orleans Urban Water Plan provides sustainable strategies to address flooding caused by excess runoff and subsidence caused by the pumping of stormwater. The plan provides a clearer vision for a new paradigm of water resource management, the urban design opportunities, and the economic benefit of implementation, as well as non-action.
The New Orleans area is situated on land built by the MS River. Over time, development pressures and the advent of new technologies have pushed human settlement into vulnerable areas and masked natural processes that have traditionally sustained the landscape. The region is also highly susceptible to the effects of climate change, specifically increased storm intensity and relative sea level rise. The plan works in the concept of multiple lines of defense, which relies on structural flood protection measures. Levees, the predominant structural protection infrastructure in the area, cuts off natural hydrologic flows, which exacerbates subsidence.
- Delay stormwater by using bio-retention and infiltration strategies
- Storing stormwater in the landscape longer by retrofitting canals and finding space for new canals and ponds
The existing drainage infrastructure is built on the idea of drain, pipe, and pump. This has caused high rates of subsidence that impacts the quality of roads and the effectiveness of drain pipes. This plan proposes a new method for managing water, which adds capacity to the existing drainage system and minimizes subsidence rates over time.
- Divide the water basins based on an existing ridge in the city
- Drain stormwater through existing and upgraded infrastructure
- Raise water levels of canals during dry seasons to reduce subsidence
- Build/retrofit streets to detain stormwater
- Utilize neutral grounds (medians) to store water in rainfall events
- Design parks to accommodate flood waters – reducing the vulnerability of the hard drainage system
The Greater New Orleans region has historic reasons it has turned its back on water. Whether it is walls to protect from flooding or pumps to keep the city dry and mosquito population low – the cultural attitude toward water has discounted the opportunity water infrastructure to connect neighborhoods, build new industries based on water management, and stabilize property values in adjacent areas. This plan addresses this by providing the economic case for this new paradigm of water management and communicating the aesthetic benefits provided by well-designed open spaces that connect neighborhoods and provide room for water.
- Remove some existing flood walls around canals that have upgraded pumps and no longer require walls
- Design and build a number of pilot projects in the study area to show the many benefits of plan implementation