• Customer
  • GNO inc.
  • Location
  • New Orleans
  • Scale
  • L
  • Period
  • 2011-2013
  • Partners
  • Deltares
  • RHDHV
  • Waggonner & Ball Architects

New Orleans has long denied the fact that it is naturally situated in a delta, and has worked to keep water from infiltrating the city. However, the ground level of the city is slowly subsiding and behind the dikes, peak rainfall causes flooding and damage several times a year. As part of an international consortium, H+N+S designed a new water system for the city and a new perspective on water management for New Orleans.

Motive

City in the Delta

In 2005, Hurricane Katrina caused extensive devastation in New Orleans. Several key levees broke, and large parts of the city were flooded, resulting in more than 1800 deaths and $81 billion (USD) in damage. After Katrina, considerable effort was put into improving the dikes. Local architects, such as David Waggonner, advocated for the reconceptualisation of the city’s relationship with its natural surroundings and the characterisation of New Orleans as a ‘living city in the Delta’.

Dutch dialogues

In a series of discussions called the ‘Dutch Dialogues’, Dutch water experts and US stakeholders explored the options for a new water strategy for New Orleans. H+N+S were involved in the specialised field of water and design. Though the dialogues, a perspective was developed for the city: flooding would be limited by ample storage space for water (catchments) and water would become a visible, attractive and integrated aspect of the city. Following these dialogues, H+N+S was contracted as part of a US-Dutch team, to develop a concrete Water Management Strategy for the city. 

The current water system mainly consists of hidden drainages, focussed on quick discharge
This system has reached its limits
Due to deep drainage, the soil subsides
The water system is hidden and monofunctional
Problems occus mainly in the lower lying parts of the city
In the former swamps
The solution lies in the underground; the city as a sponge

Improvements to water management can contribute significantly to the quality of life in the city

The starting point for the project was a new take on New Orleans as a ‘delta city’: a city where the dangers of the delta are effectively managed and reduced, while the qualities of the delta are embraced as a crucial aspect of the urban lifestyle. The existing water infrastructure requires gradual transformation into a system that is better suited to the specific characteristics of the soil in the area, utilising the qualities water can offer; both aesthetically and functionally. In the plan, the natural landscape of New Orleans (backslope, bowl, ridge and polders) was utilised and integrated into urban development to a much greater extent than in the past.

Approach

Integral + Innovative

An innovative aspect of the proposals was the close connection between science, engineering and design. This integrated approach is unique not only for New Orleans, but also by Dutch standards. In cooperation with hydraulic engineers, water issues were quantified accurately and proposals for a monitoring system were developed. The concept for the system was developed jointly and tested interimly, with adjustments made on the basis of results and calculations. Local insights throughout the city were taken into account and integrated in the overall system plan. Specific characteristics of the town and the subsoil were also considered and integrated into the design. From this information and research, comprehensive plans could be formed for the development of individual sub-basins.

Framework Watermanagement strategy. The Outfall Canals, the concrete canals, can become an interesting linear park. Water can become an asset of the city.

Result

Sharing the burden

The new approach positions water as a much more integrated, intertwined aspect of the city, through to small-scale neighbourhoods and individual plots of land. It is at this grassroots level that many of the new measures are necessary and targeted. In the new approach, areas may no longer simply discharge the excess water from their individual plots, but first capture and store it locally, to reduce pressure on the water system. Each part of the city makes a contribution to easing the water problem, and therefore, also actively contributes to the solution. 

Delay, store, drain

Pressure on the city drainage system during heavy rainfall is reduced, by creating mechanisms to hold rainwater and let it seep into the ground, before it enters the drainage system. The next step is to locally retain water. Finally, after the water is retained, it can slowly be discharged. In practise, the holding, storage and disposal of water (delay, store, drain) is smoothly integrated into a cohesive system. 

Current situation
The outfall canals as linear parks

Water in the everyday environment

Existing and new water coarses within the city is no longer diverted straight into drainage gutters, but instead forms part of a green network and the basis of an urban ecosystem. The banks of river systems are as green as possible and feature hiking and cycling trails. Streets are renewed and newly profiled to offer plenty of space to slow water movement. Wadis and permeable paving are crucial in this area. The people of New Orleans are also inspired by the new approach of a ‘delta town’ and on private plots, green roofs and rain gardens are increasingly being incorporated. 

New Orleans and Bayou St. John
Urban perspective: the network (streets, canals), the landscape and the water management are integrated. (image Palmbout)
Pilot project La fitte blueway (image Bosch Slabbers)
In een long-term investment strategy streets are transformed (image Bosch Slabbers)
A circular water system guarantees good water quality
Louisiana wetlands
New Orleans as a delta city with blueways, greenways, parks and integrated wetlands. (image WB architects)

"Turning a potential nuisance into a valuable resource"

Living with water

The site-specific approach, tailored to local conditions, leads to unique solutions and aesthetic diversity within the city. The operation of the water system becomes visible in the daily living environment, not only during heavy rain, but also in drier times. The city develops a more balanced relationship with the water on the long term, and the differences between periods of excess and deficiency are reduced. By restoring groundwater levels, soil subsidence in the vulnerable areas is reduced. The new approach considers the full cycle of water in its entirety, and therefore prevents wastage.

International team

The Urban Water Plan New Orleans was prepared by an international team under the overall leadership of Waggonner & Ball Architects. 

Bosch Slabbers, H+N+S Landscape Architects, Robbert de Koning, and Palmbout Urban Landscapes were responsible for the design, in cooperation with: Waggonner & Ball Architects, Manning Architects, Brown +Danos Landdesign, FutureProof, Bright Moments Geosyntec Consulting, Arcadis, Deltares, Royal Haskoning , TU Delft, City of Rotterdam, City of Amsterdam, CDM, GCR, KBR, Dewberry, Waldemar S. Nelson Engineers, Eustis Engineering, Sherwood Design Engineers.
Supervion by: Han Meyer, Ton Schaap, Lodewijk van Nieuwenhuijze

More info: www.livingwithwater.com

The Urban Water Plan iPad app

Want to know more?

Pieter Schengenga Director, Landscape architect
Jaap van der Salm Junior project leader, Landscape Architect
Lodewijk van Nieuwenhuijze Founder, Landscape architect

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