Dutch Dialogue 2

The Dialogues Process

Dutch Dialogues II was held on October 10-13, 2008, and built upon groundwork laid during a preliminary workshop held in March 2008.  Dutch experts came to New Orleans, got a crash course on the New Orleans political and planning landscape, and then went into the field to  “see and smell and walk” the provocative, confounding New Orleans landscape.  The initial reaction of the Dutch planners and designers was “Where is the water and why is it hidden?”  .

During the workshop, the Dutch participants were joined by peers from elsewhere in the US and from New Orleans. The entire group was given broad instructions to develop illustrative plans for the New Orleans redevelopment process, with a primary focus on water and how that can add to economic development.

Our scales of work were three: one regional and two neighborhoods.  The groups worked separately, although regular feedback sessions ensured continuity and integration of the separate efforts; one thing that the groups purposely avoided was a haphazard, ad-hoc approach to integrating the scales.  Participants also worked very hard to respect the identity of New Orleans, to avoid proposing radical changes, and to integrate their proposals into the existing urban fabric.

The volume of sketches, drawings and ideas produced during the workshop was overwhelming; refining those ideas into a coherent, illustrative whole was a challenge.  The images that follow are but a sampling of the Workshop’s output, and the images are designed to provoke as much as inspire.

Dutch Dialogues II ended with two detailed presentations on October 13, one to a selected group of key New Orleans public officials and institutions, and one to the general public; both presentations were held at Tulane University.  What follows is a summary of the detailed presentations.

The Regional Scale

1.    The Regional Workgroup: An Opening Thesis

In 1953 the Netherlands was struck by a devastating flood in which nearly 2000 people died.  The flood’s impact was overwhelming, but it also led to a new beginning in the Dutch approach to Living with Water.  Dutch policymakers and engineers developed new solutions to mitigate flood risk, and increase economic value; they also tried to create spatial quality, identity and new opportunities for nature and recreation.

The 1953 flood forced the Dutch to think differently about their future.  The Netherlands today is perhaps the world leader in sound, innovative and adaptive water management policy.  The 1953 disaster enabled us, or forced us, to find new opportunities, create new qualities, invent new technologies — in short to become stronger and more resilient.

Katrina was a terrible hurricane and a worse disaster, and yet it gives New Orleans a unique opportunity to develop an ‘American approach’ to sound water management.  New Orleans and Louisianans can show America and other parts of the world how to live more robustly, Cajun- and Creole-style, in a challenging, beautiful river delta.  The world’s changing climate also allows New Orleans to become a test-bed for new ideas and adaptation strategies.

Thinking about the future is more than repairing the damage—it is also means imagining what New Orleans could or might be.  This “imagining process” can yield new thoughts about what you are and want to be, which qualities to hold onto to and which new qualities to create, what identities are permanent and which new ones to develop, and, finally, what opportunities to exploit.

In Dutch Dialogues, we began by thinking on a larger, regional scale.  After that, we looked at possible solutions for the city as a whole, and then we looked at neighborhood-specific approaches.  We kept reminding ourselves to integrate the City of New Orleans and its unique neighborhoods and identities into the larger scale.

Those very identities provide a wonderful palette for a designer, many challenges for an engineer and many opportunities for a planner.  Dutch Dialogues participants left New Orleans with a firm belief that a new strategy on planning — with and for the water—was needed, and that water should become, once again, a primary quality of the City’s identity,–as it is in Amsterdam, Rotterdam, and Venice.

2    Regional Plans and Safety

Many solid restoration and redevelopment plans for coastal Louisiana, the Mississippi Delta and New Orleans already exist: the LACPRA plan developed by the State of Louisiana and the LACPR plan of the US Army Corps of Engineers (USACE).  Both plans call for a 1-in-100 protection level by 2012, and include the restoration and strengthening of the Corps’ Hurricane Protection System (HPS) levees, flood walls and gates, the construction of new, more robust pump stations, and the construction of three major storm surge barriers:
IHNC barrier (east, at the confluence of GIWW and MRGO
Seabrook barrier (north, at the outlet of IHNC into lake Ponchatrain
South Gate (South of Mississippi, outside the scope of our study)

We believe this infrastructure is crucial and assumed in the workshop that all would be built.  Again: Safety First!

3    Structures and Backbones

A sustainable New Orleans is, prima facie, a safe New Orleans, and that means increased flood protection levels.  By creating safety for New Orleans, you make sustainable value — economic, social, environmental — possible.

We identified at the outset five major structuring elements for our regional New Orleans strategy:
The Mississippi River
Lake Pontchartrain
Canals
Historic authenticity
Natural environment

Strong structures have strong backbones, and we identified four in New Orleans, each running east-west:
The strong levee and prominent coastline along Lake Ponchatrain
The strong levee and prominent river esplanade along the Mississippi
A slightly elevated, sandy ridge: the Gentilly Ridge, a stretch of high ground along the former banks of Bayou Gentilly, running west to east and parallel to the two backbones noted above
Claiborne Avenue, between the Gentilly Ridge and the Mississippi.  Claiborne used to be a prominent feature of the New Orleans landscape, but recent urban and transportation developments have made it less visible.

4    Building Blocks for Redevelopment

Three building blocks underpin our regional protection and development model. These blocks form layers that reinforce our integrated approach:

Safety
Storm water storage
Environment and quality of life

Safety
The first building block is safety.  Protection against hurricanes, floods and excess storm water is key for New Orleans redevelopment.  Combining the city’s structural backbones with the Corps’ “hard shell” will enhance protection from hurricane and storm threats.  Thus, while the Corps’ 1-in-100 year protection is crucial, this shell should be strengthened to increase the level of protection.

New Orleans must also be able to close the doors of its shell in emergencies  These doors are the storm surge barriers already in place in the drainage canals (like 17th Street Canal and London Street Canal) and those under design and construction for the navigable canals (IHNC, Seabrook and South Gate).  In addition, the development and restoration of natural and currently degraded wetlands is important, particularly on the east side of the IHNC and in Lake Borgne, which is perhaps the “Achilles Heel” of the New Orleans HPS.

Looking forward, the backbones could become the natural dividing lines for separate compartments of the New Orleans protection system, preventing one levee failure from filling the whole “bath tub”.

Storm water storage

Considering New Orleans’ intense rainfall, enhanced drainage capacity (pumps) and more storm water storage should be added.  In the Netherlands we always combine these two drainage elements, while we conclude that New Orleans has focused on pumps, mainly due to lack of space.  Additional water storage capacity lowers the risk of storm water problems and localized flooding during hurricanes. It also enables water tables (and risk levels) to be more actively managed, just like in the Netherlands. The beneficial impact of additional storage on protection levels should not be underestimated.

Post-Katrina, there are unique opportunities to create additional water storage.  The most common storage features are canals, lakes and ponds, and wetlands.  Additional canal capacity already exists within the City: many old canals were covered or backfilled over the past century.  Conversely, new canals could be added to existing drainage canals in many parts of the city.  Park areas could be used for storage, and wetlands could be created along Lake Ponchatrain, north of Saint Bernard in Bienvenue and/or in other bayous.

Environment and Quality of life
Adding environmental value to the city and its surroundings will add to the City’s sustainability.  A comprehensive plan for the city should include at least some of the following:
New canals in New Orleans East to create water storage and a new urban feel (comparable to that in the Netherlands) where people enjoy living near the water
Existing canals should be reshaped from their present “concrete culvert” and “invisible” appearance, with high and steep floodwalls, into more sustainable, natural, inviting and attractive elements
Water storage in urban parkland to add “green-blue” areas were the ecology can flourish and recreation is possible
Broadening (strengthening) levees along the Lake and the river to add safety and for economic, residential and tourism development
Compartmentalization to promote the restoration of prominent boulevards, and add new economic and environmental qualities like green spaces, parks, attractive mixed-use development along tree-lined streets and an extension of public transport (the New Orleans street car)
Wetland restoration in Lake Borgne and in the bayous north of Saint Bernard to add robust “wet” ecosystems that are attractive, environmentally friendly, enhance recreation and tourism and improve sustainability and safety

5    Putting it all Together: An Illustration

The four-day Dutch Dialogues workshop did permit us to develop a comprehensive plan.  Instead we chose to sketch a long-term vision in which the structures, backbones and building blocks were integrated, exploited, enhanced.  We sought in short to make New Orleans a safer and more attractive city in which to live, to work, to visit, and to enjoy.

Super levee.
Adding a super-levee along the Lake Ponchatrain waterfront would substantially improve flood protection.  This levee would be built not on top the existing levee, but just offshore of it.  The levee enables development of a majestic lakeside boulevard, with numerous palm trees, lawns, parks, and small harbours and marinas as well as space for new, mixed development: hotels, restaurants, shops, condos and other housing.  It supplies what the French call ‘Joie de vivre’, giving new life to the lakefront, and giving New Orleans a new, usable waterfront.

Between this new levee and the existing levee we imagine a new wetland, acting as a bio-filer and safety valve, where rainwater from nearby neighbourhoods is stored and treated.  The wetland will improve the lake’s bio-system and its water quality.  The wetland forms a wet-dry buffer, and we see opportunities to use the buffer as a water source for internal water circulation during dry periods.

Islands
Adding new islands in the lake would create a platform to absorb and lessen storm and wave energy.  The islands are also platforms for nature, recreation, fishing, picnicking.  We imagined New Orleanians going to islands by boats and by bike, leaving life’s stresses behind to eat crawfish and crab, to mingle with family and friends, to walk the beach or take a dip in the lake.

New Water Storage.
Adding new water storage is crucial:

by redeveloping existing canals.  New Orleans’ many hidden canals should be transformed into proud waterlines, lined by native trees and vegetation.  Bayou Saint John – with its calm, approachable, accessible water –should serve as an example.  Adding new, usable bayous will transform industrial infrastructure into beautiful places, and enable a more effective water management and water storage strategy.  The canals also give structure and identity to their neighbourhoods – and maybe New Orleans will become even more beautiful than Amsterdam.

by creating more water in the lowest parts: New Orleans East could be developed into a little Venice and a little Vietnam.  We learned that 00000Little Vietnam is actually almost there, with cosy family-restaurants, floating houses, floating gardens, rice-fields etc.  New Orleans was already an international destination showcasing its cultural diversity: the new Venice and the new Vietnam just add to the international appeal of the Crescent City.

by connecting Bayou Saint John to City Park. During the wet months and during major storms, City Park could and should store more water. This is not a major problem as the bald-cypresses so prevalent there love to have “wet feet”.  By linking the Bayou to the Park, you improve your natural urban canopy and add water storage at the same time.

Gentilly Ridge
Gentilly Ridge is the former natural levee of Mississippi River and because of that is an important structure.  The Ridge’s sandy soil and slightly elevated position makes it an excellent place to live, to work and to develop.  The ridge is also the natural division between the northern and southern drainage basins. The northern part streams to the lake, and the southern part can drain east to the industrial canal.  One crucial point: as the Ridge naturally divides the northern and southern basins, planners and developers must pay extra attention to if, how and where ridge is penetrated.  The importance of the Ridge cannot be overstated

Lake Borgne and new Fresh-Water Wetland
New or expanded fresh water wetlands east of the City will reintroduce nature to the edge of the city.  This will add a new dimension and new opportunities to the city.  Perhaps here you can rent a canoe, go fishing, watch the birds and wildlife, and maybe even the alligators — if you can paddle fast enough!

Claiborne Avenue
Claiborne Avenue should be redeveloped as a wonderful place to live and work, as a city boulevard, with a canal down the middle, covered by broad trees creating a green umbrella.  Here, we see water that is not only attractive, but also beautiful but also transports storm water to the industrial canal.  We could also imagine a Streetcar or other light rail along Claiborne Avenue.

Gentilly: A Rising Middle Class

The Gentilly area of New Orleans is a mixed, middle-class neigborhood bordered, respectively, by the London Avenue Canal and the Inner Harbor Navigation Canal (IHNC) to the west and east, and by Lake Ponchatrain and the Gentilly Ridge to the north and south.  Gentilly, settled primarily in the 20th century, was reclaimed from old cypress swamp and thus much of it lies below sea level.  There was a tremendous diversity of housing typology, ethnicity, and socio-economic class in Gentilly; during our short tour there we found a proud, mostly confident yet worried population.

Gentilly’s post-Katrina redevelopment has been ad-hoc, haphazard.  Between 6000 and 8000 empty properties remain in Gentilly, which makes it difficult to predict the area’s future.  We saw in those empty properties, however, an opportunity to enhance the area’s flood protection, which in turn would make the area more attractive to New Orleans’ middle class.

Our proposals consist of designs for the area itself, its water management systems, public transport and connections to New Orleans as a whole.  Flood safety and risk reduction for Gentilly, and for all “low” parts of the City, were always on our minds.

Our Framework

We began with the flood challenge.  Water surrounds Gentilly and it is thus threatened by rising waters in Lake Pontchartrain, wave energy from the Lake (often driven by storms), and substantial storm-related rainfall that overwhelms the area’s drainage system.  Each threat warrants a response, and each response must be integrated with the other.  The responses should also generate new, attractive identities and opportunities for Gentilly and the City.

Gentilly’s geomorphic variations in the area as well as its historical growth patterns were two of our anchoring themes.  There is no need to reinvent a new Gentilly; rediscovering an older Gentilly is perhaps better.  We therefore sought to enliven an existing transportation connection (Elysian Fields) and an elevated ridge – the Esplanade — between the City and the Lake, via Gentilly.  New “water” for the Gentilly “polder” adds a new identity and level of safety to this area, and urbanization can be focused upon the Avenue and canals.

Challenge 1, the New Orleans Lido in Lake Pontchartrain

We assume a barrier at the Rigolets and Chef’s Pass will be built, which in turn will substantially mitigate high water levees in Lake Ponchatrain.  We (like the Regional Group above) propose building a number of islands along the lakefront.  Like Venice’s Lido, such islands break the waves and create a quiet, shallow lagoon between the existing lakefront and the imagined islands.  No chan

ge in lakefront elevations are warranted, although broadening the lakefront levee (lake ward) would provide extra protection and would also allow for new, densely-planted Lake Front boulevard to be created.

The northern peripheries of the lakefront islands must be strongly-built to break the waves during periods of hard north winds.  The southern peripheries can be gentle, soft and sandy; and beaches are an option here.  The lagoon offers opportunities for swimming, fishing and sailing.  Navigable passes between the islands maintain the connection between the lakefront and the lake, and will also ensure that the lagoon water is constantly refreshed.  The islands can be used for nature, residential or recreation purposes.  They can be connected to the main land by ferries, water-taxis or by bridges.
Elysian Fields Avenue connects the Mississippi River and Lake Pontchartrain via a tight, linear axis, and it also integrates various grids in New Orleans.  Elysian Fields Avenue should terminate at lakefront, and that terminus is the most attractive point to connect one of the new islands.  At this terminus, a new harbor, restaurants, hotels and a beautiful plaza or boardwalk would create a welcoming public space – a new icon for lakefront New Orleans

Challenge 2: Thousand Trees Elysian Fields Avenue

Elysian Fields Avenue should be restored as Gentilly’s backbone.  One thousand or more native trees should be planted along Elysian Fields to give shade, character and charm to it.  Such trees reduce summer heat stress and absorb surplus surface/ground water in low-lying areas.  Other public squares/spaces in Gentilly should also receive such plantings, giving the entire area feel similar too, but also distinct from, the Garden District.  We imagine a new streetcar line along Elysian Fields, which would connect the lakefront “Lido-Island” and Gentilly with the French Quarter and the Garden district.

Challenge 3: Gentilly’s New-Old Water System

We believe Gentilly’s water system is insufficient and frail.  Water drainage and supply has been buried, causing leaks, water loss and making the groundwater levels difficult to manage.  Water storage has been neglected.  We believe that making the water system more dynamic, robust, and visible is essential.

Our approach allows for system differentiation throughout Gentilly.  Gradients and elevation changes should become more apparent and visual.  In Gentilly’s lowest areas, we would (re)introduce canals with circulating water, and in the highest parts we see a role for wadi’s (small, grassy culverts that fill with water during heavy showers and then drain naturally.  The system’s vigor, moving water, its aquatic plant and fish species balance/health will mitigate mosquito/pest concerns.

Challenge 4: Bayou London Avenue

At present, a huge, unsightly concrete floodwall defines Gentilly’s western border.  Behind the floodwall lies the London Avenue Canal, one of the four major outfall canals which drain central New Orleans.  The Canal’s water is brackish due to the Canal’s open connection with Lake Ponchatrain.  The floodwall prevents water from the Lake from flooding New Orleans.

Installing a pump station at the end of the London Avenue Canal (near the Lake) would substantially increase flood protection levels in Gentilly; it also new, attractive redevelopment opportunities.  The new pump station, providing thus protection for the canal behind it, will allow for the removal of the flood walls from the canal.  This will, in turn, reintegrate the canal water course back into Gentilly’s topography.  No longer will London Avenue Canal be solely an ugly drainage asset, but will instead become part of Gentilly’s “front yard”, welcoming nature, water and people into the community.  London Avenue Canal will become Gentilly’s “Bayou St John.”  The canal’s brackish water will be replaced by fresh water and the reinvented canal will add a new buffer into the area’s new, dynamic water system.

Challenge 5: Acupuncture

Instead of large-scale, ad-hoc development in the existing Gentilly framework, we would propose a more careful, considered (re)development process that leads to nodes of more concentrated development without, however, changing the scale of development in Gentilly.  This is more a matter of changes to building and zoning codes than to urban design practices.  We also believe that those same codes should try to promote (re)development in areas with higher elevations.   This enhances safety and resiliency.  Creating new canals increases water storage capacity and enhances the water system, and also creates a new urban feel, new development possibilities and atmosphere in Gentilly.  The remaining empty, abandoned lots in the lower parts of Gentilly can also be put to use: creating playing grounds/parks or emergency water storage for all of the “new kids on the block.”

The Hoffman Triangle: A New Urban Water Management Strategy

Introduction and summary

The Hoffman Triangle is one of the most vulnerable neighbourhoods in New Orleans: vulnerable for flooding from rainfall, which happens frequently, and vulnerable for social and economic decay, related to a lack of spatial quality.  Our goal was to address flooding while making the neighborhood more attractive.

To do this, we adopted a new approach to urban water-management by replacing parts of the existing underground drainage-infrastructure with a new hydraulic system of water-elements – the Cascade.   We believe that the Cascade-concept will reduce flood risk and flood and improve the spatial quality of the urban environment.

Water and soil

The Hoffman-triangle is part of the Uptown/Garden District – between the New Orleans Central Business District and Audubon Boulevard, and between Mississippi River and Xavier University.  It can be considered a coherent water-management-district, with drainage-infrastructure linked to Pumping Station 1 in the north of the area.

Two water-management and urban structure characteristics of the area are important:

First, the difference between the high grounds (+14 ft) directly alongside the Mississippi River Bank, and the low grounds(-6 ft) in the north, where one finds Pumping Station 1 which collects drainage water and pumps it into the Washington Canal.

Second, the differences in soil quality, which is related to the differences in height. The soils in this cross-section between the Mississippi and Lake Pontchartrain show a remarkable differentiation in the composition and quality of the soil.  Soils along the riverbanks are steady clay, a product of sediment deposits of the river during many thousands of years.  Comparable soils are sound along the Metairie ridge and alongside the borders of the Lake.  Between the Metairie ridge and the riverbanks however the soil composition a peat-like, in some places tens of meters thick.  This soil works like a sponge: because of drainage the soil is shrinking, compacting and oxidizing, causing ground subsidence of about 1 cm (0.4 inches) year.

Rainfall in southern Louisiana can be extraordinarily heavy, with extremes of 8 inches of rainfall in three hours (200 mm/3hrs).  Correspondingly, New Orleans drainage-infrastructure and pumping-capacity in this area are powerful hydraulic structures (1 inch/hr the first hour; .5 inch continuously) — far more powerful than what is used in the Netherlands.    Nevertheless floods in the lowest points in the Hoffman Triangle are common.  We thus concluded that existing hydraulic system is insufficient when it comes to preventing nuisance or worse flooding.

In the following images, the course of a rainstorm in the Uptown-area is illustrated.  Initially, the pumps and the underground drainage system can cope with moderate rainfall.  In time, however, rainfall levels exceed the pump/drainage capacity and water backs up onto the streets – first in the lower parts of the area (the Hoffman Triangle) and then nearby, in higher elevation neighbourhoods.  (Editor’s note: the above should be put in a separate block with imagines)

Ongoing subsidence will exacerbate existing flood tendencies.  The underground drainage-system (and also underground infrastructures for drinking-water, sewerage, electricity, gas) will be frequently damaged by the subsiding soil.  This damage in turn further depresses the drainage system’s performance.

The area’s drinking water system is also failing, losing 117 million-cubic-meters of water per year because of fracture-induced seepage.  Additionally, the sewerage system – overloaded with groundwater – performs poorly during rainstorms.  Thus, both the underground and above-ground infrastructure — roads, homes and commercial property — are damaged by soil-subsidence.  Repair and maintenance of this failing infrastructure is (excessively) costly, both to private individuals, nearby businesses and to the public sector.

The Hoffman Triangle presently has a frequently changing ground water level: high during storms and hurricanes, causing flooding, damage, discomfort and danger; and low during dry periods and droughts, causing or exacerbating soil subsidence.  This is not sustainable, nor does it contribute to a safe urban environment.

Maintaining the ground-water at more constant levels will help the City deal with the inter-related problems of flooding, soil subsidence and rapidly deteriorating infrastructure.  We believe that the water management system should make it possible to introduce extra water into the area in dry times, and to store extra amounts of water during rainstorms.

In the Netherlands we have been implementing the Retain-Store-Drain approach over the past decade.  By expanding rainwater storage and retainment capacity, rapid removal of excess rain/storm-water is no longer necessary.  This approach might be fruitful for New Orleans as well.

A new hydraulic principle: the Cascade

The Cascade is a hydraulic system composed mainly of linear water-elements at ground-level, perpendicular to the Mississippi River. Run-off from higher elevations (near the river) to lower elevations in Hoffman Triangle will be guided by these water-elements throughout the area.   Thresholds in the elements will prevent the water from running downstream too quickly.  Normal groundwater pressure from the Mississippi River will provide the Cascade with a steady supply of fresh, circulating groundwater.  During heavy storms, groundwater intake from the Mississippi will be reduced or closed, allowing the Cascade to store large amounts of rain water. During droughts and dry months, a simple pipe-and-pump-system can supply the Cascade with river water.

Cascade elements (primary and secondary) allow water managers to maintain ground water lev

els within a narrow range, thereby adding to system resiliency and substantially decreasing the rate of subsidence.  Implicitly, the Cascade system should also decrease infrastructure O & M and repair costs.

Buildings and gardens in the area should have elements that temporarily store rain and storm water before delivering it to the cascade-system.   Such water-retention elements are commonplace in many residential and commercial developments in the US; they should also be applied in New Orleans.

Note: the Cascade will provide continuously streaming water which will prevent stagnant water (mosquitoes) from developing.  Natural and native plants should be added to Cascade thresholds to naturally purify the water, making parts of it suitable for recreation

Integrating the Cascade

The Uptown/Garden district is a coherent urban district in terms of spatial coherence and structures.  The area is a grid, with 300 x 300 ft blocks, and streets 60 – 120 ft wide.  Grid deviations occur due to changing orientations (heritage of the area’s plantation past) and differences in height.  These deviations yield zones with different types of land-use as they extend down from the Mississippi to the Hoffman Triangle.  These deviations allow us to introduce and integrate the cascade-system into the existing urban fabric, not only to solve the water-problem but also to improve the spatial quality of the urban environment.

(a) the changing orientation of the grid
The gradual changes of the orientation of the streets perpendicular to the river stem from the agricultural history of plantations found here years ago.  The plantations were long parcels, running perpendicular to the river, with river bends causing the parcels to gradually change direction.  The demise of the plantation culture and rise of the urban grid pattern introduced triangle-shaped zones where the parcels merged.  Today, many of these triangles are neglected public space.  In the Cascade, these triangles provide space to widen the water-stream for storage and for vegetation necessary for water purification.  Because the triangles lie mainly between and parallel to the large (underground) drainage pipes that end at the pump station, the Cascade-induced water elements add capacity to the drainage system.  Just as important, the once derelict triangles are transformed into vibrant public spaces.

(b) Different zones from Mississippi to the Hoffman Triangle.
Elevation differences are linked with differences in housing typology and density of the urban blocks.  Between the River-banks and Pump Station 1, we can distinguish four zones and imagine new public identities for them.

Zone 1: the Wells – centres of public life

Zone 1 is situated directly alongside the banks and levees of the Mississippi, generally with a low density with a FAR (Floor Area Ratio) less than 0.3 (estimated!).  Surprisingly, this zone has the highest elevation (great river views), but has very low density and little-to-none residential use.  Building here are industrial/warehouses.  We believe that this zone has strong potential for a denser, and more residential, use.

The wells of the cascade will be located in this zone.  The wells will be attractive public spaces, and combining them with new, denser development (with FAR’s > 5) will enliven urban life along the river banks.  Adding a new streetcar line along the Mississippi, with stops next to the wells, will also improve the urban quality of the wells.  All new residential development and nearby public space should have temporary water storage elements in their design.

Zone 2 : Cascade integrated into the public space

Zone 2 is the most densely populated and built residential area (estimated FAR > 1.5).  This is the zone is relatively high and dry, removed from industry, and can be considered as a standard of residential New Orleans neighbourhoods.  Most of the area’s buildings are in a good shape and well-maintained.  Much of the public space, however, is in less-than ideal condition.  Our challenge was to improve the quality of the public space.

The cascade-system can be constructed along some of the existing right-of-ways extending away from Mississippi and between the north-south streets which are important for car-traffic. Constructing the Cascade at grade may radically improve the public space:  the cascade will become a recreation zone where people learn to live with water, and it will provide attractive bicycle and pedestrian routes linking streets and neighborhoods.   The Cascade design allows it to absorb varying amounts of water: small amounts in dry periods, large amounts during storms.

Zone 3: Cascade integrated in the urban blocks

This area is particularly vulnerable to flooding, and many in the zone are still recovering from Hurricane Katrina.  Many blocks have residential return at just 50% and have an estimated FAR of less than 0.5. Many shotgun-houses can be found in this zone.

To increase this area’s desirability, we imagine integrating the Cascade-system into the interior of the block.  By doing so, we providing unique quality to the backyards and gardens of the residents; we also introduce a special quality to these lots not found elsewhere in New Orleans.

Zone 4: Wetlands Residential

Zone 4 concerns the Hoffman Triangle and surroundings.  Here we need to create substantial water storage capacity to prevent overloading the pump station.  Because residential density in the Triangle is low (still recovering from Katrina), creating new water storage should be possible.  We imagine a carefully-prepared urban design, which defines where water storage will located, the landscaping of this ‘water-park,’ and the relation between the water-park and residential lots.  Instead of being simply the ‘lowest’ part of the area, Hoffman Triangle can become a very attractive residential area in which the water-park is an advantage not a disadvantage.

Conclusion:

The Cascade-system and its water elements will be integrated into the existing urban fabric.  It will substantially reduce flood risk, provide more spatial quality and coherence, and allow the different zones/neighbourhoods to capitalize on their own identity and exploit the special conditions of their blocks and streets.  This new, diversified urban fabric will attract different people with different lifestyles, which we believe is a hallmark on this multi-cultural city.  The Cascade also creates higher residential densities at the highest elevations, which will mean that other (even more vulnerable) areas in the city can be rebuilt with lower density neighbourhoods.

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