In the post-Katrina landscape of Louisiana and the Gulf South, nothing is more pressing than the challenge of how to sustain settlement in the coastal regions. The 2009 mapping, by Louisiana State University professors Michael Blum and Harry Roberts, of predicted sea level rise by 2100, forces a dramatic rethinking of options for the future. 1 Without massive land-building efforts, the coastal region will disappear within a relatively short time. This clearly has implications on a regional scale for the future of the landscape and of the towns and cities of Southern Louisiana. The mission of Louisiana State University’s Coastal Sustainability Studio, initiated in 2009, is to address this challenge in the context of finding sustainable solutions for human settlement in the region.
For several centuries now, in fact, the forces of settlement have been altering the natural flux of the Mississippi River, creating a complex landscape that is the result of the geophysical forces of the Delta, massive civil and environmental engineering, and the culture of the people of South Louisiana.
For thousands of years the Mississippi coursed freely across the Delta plain as it searched for faster routes to the Gulf of Mexico. Over the last 300 years, the remaking of the coastal landscape for the purposes of resource extraction, national expansion, commercial shipping, urban development, and flood protection has severely curtailed the deltaic processes of the river. Today it is unmistakably clear that the results of human intervention — dramatically escalating land loss and rapid wetland destruction are only the most visible signs — are imperiling the future of Louisiana. The amplification of the impacts of these interventions has brought us to this moment in the early 21st century when, following a series of disastrous storms, the engineered landscape of coastal Louisiana has reached its breaking point.
New Orleans has been described as a city with a “near-perfect situation and an almost unimaginably bad site.” 2 The city’s location near the mouth of the Mississippi gives it strategic command over the continent’s most significant inland waterway and makes it a key player in the mediation of international trade. At the same time the geophysical realities of its location, especially the low elevation and land subsidence, are less than ideal, making the city increasingly vulnerable to flooding and storms. But again, it is human activity — the constraining of the delta with levees, the petrochemical industry’s fragmentation of coastal landscapes, and the inappropriate location of urban development — that has accelerated the loss of protective wetlands and barrier islands and created the catastrophic situation we face today. Many communities are highly vulnerable to the potential damages of future flooding and storms.
LSU’s Coastal Sustainability Studio brings together faculty, research fellows, and undergraduate and graduate students of the School of the Coast and Environment, the College of Engineering, and the College of Art and Design. Scientists, engineers and designers collaborate on projects and develop techniques for reducing environmental vulnerability and enhancing community resilience.
More specifically, the CSS’s mission is to undertake work not only speculative in its outlook for a long-term future but also community-driven and influential in real ways. This drives a project approach that incorporates political and economic realities as well as research-based investigation into possible scenarios. What we propose in development terms is thus constrained by the likely realities of ecological impacts (for instance, the risk of future storms and sea level rise); likewise, considerations of ecological sustainability are tempered by social and economic imperatives. We have found that this approach, far from limiting our ability to think broadly or respond to community needs, has been a blast of fresh air for a place tired from years of grand promises and little return.
Our fundamental conceptual break has been with the primacy of the master plan. We identify key topics for speculation through consultation, research and analysis; key themes have included housing and neighborhoods, wetlands regeneration, productive landscapes, and urban recreation and economic development. We then develop a series of transparent scenarios, making clear the assumptions that underpin them so that they can inform decision-making, and we evaluate these scenarios against various performance criteria, including carbon footprint, sea level rise, storm and flood defense, investment and potential return. In our recent studio we further developed these scenarios into a larger vision for the future of neighborhoods within a restored coastal environment.
The CSS regional approach starts with a commitment to return the Mississippi River to its role as delta builder. But this is not simply a call for restoration. The tremendous growth of communities, industries and shipping along the river’s banks has profoundly altered the entire landscape. Any changes to the current operation and control of the river will be a highly complex procedure that must engage coastal scientists, engineers and designers.
The primary action that we have proposed is a series of spillways constructed at strategic locations along the gulf, with the spillway gates to be periodically opened when the Mississippi is high, providing a steady pulse of sediment that over the century will build up, maintain and protect large expanses of land. There is precedent for this approach: west of the Mississippi, near the mouth of the Atchafalaya River, the Wax Lake Outlet has for several decades been diverting sediment and building up a significant delta. And other diversions, like the Bonnet Carre Spillway, which redirects Mississippi floodwaters into Lake Pontchartrain, have been constructed to protect New Orleans (although in this case the diverted sediment is wasted at the bottom of the lake).
Our delta-wide proposal encompasses five diversions operating at the endpoints of the five historic basins of the delta, with each diversion designed as a hybrid between soft and hard infrastructure, strategically placed with regard to ecological, economic and settlement patterns. Our goal is to make the river once again flexible and powerful, with the resulting land-river dynamics working in harmony with existing and future delta communities.
But “giving the river room” at the regional scale presents huge challenges and opportunities at the local scale. It is not enough simply to allow the river to rebuild subsiding land. Our communities must develop the tools to grow in harmony with changing conditions. The CSS approach to the city, town and neighborhood is predicated on nurturing settlement patterns that work with wetland and river processes and that are resilient to their sudden fluctuations. The neighborhood as we know it will have to evolve — to become better integrated with natural systems and flexible to changing water levels. Its architecture will have to become nimble, and increased open space will be needed to absorb seasonal floodwaters. Much of the Lower Ninth Ward, for example, was formerly wetlands, and will need to be re-imagined as a flexible urban/protective/middle zone once again. To do this, we propose restoring the Central Wetlands Unit — the 30,000 acres of cypress forest that once protected the Lower Ninth from hurricanes, until the cutting of the 76-mile-long Mississippi River Gulf Outlet in the mid 20th century brought saltwater into the marsh, killing the cypress in just a few years.
Living with sea level rise, land subsidence, and increasingly destructive storms is a bleak and terrifying prospect for the citizens of Louisiana. A sustained and resilient future for New Orleans and coastal Louisiana will depend upon the power of the Mississippi River to build land and feed the wetlands that provide essential protection from storms. The Coastal Sustainability Studio seeks to bring the power of the river back to the heart of New Orleans and challenges us to see a future based not on the river’s control but on its potential to shape a new landscape.
Mississippi Delta With its ability to carry and deposit rich sediment, the Mississippi River has for centuries built up and maintained the fertile land of the Delta. The progressive re-engineering of the river and the delta in the past three centuries — much of it under the direction of the U.S. Army Corps of Engineers — has produced significant regional and national benefits, serving especially the shipping and petrochemical industries. But we know that these economic benefits have been purchased at enormous environmental costs, and that the sustainability of the gulf ecosystem is threatened. The devastation wrought by successive hurricanes — Katrina, Rita, Ike, Gustav — and the explosion this summer of the offshore Deepwater Horizon and the catastrophic oil spill that followed, have heightened awareness that the region faces a perilous future. The Coastal Sustainability Studio is focused on exploring solutions that match in boldness and scale the gravity of the problem: restoring the power of the Mississippi River. [Image credit: Coastal Sustainability Studio]
Historical distributaries and delta basins For millennia the Mississippi River flowed south from its northern headwaters, searching for the shortest route to the Gulf of Mexico; along the way it created and abandoned a series of hydrologic basins. Formed at different times, these sub-regions are subtly distinct, with different types of soil and rates of land subsidence. [Image credit: Coastal Sustainability Studio]
Taming the river After the Great Mississippi Flood of 1927 — the most destructive river flood in U.S. history — the U.S. Army Corps of Engineers began constructing an extensive system of levees stretching from Missouri to Louisiana. Within decades the flood control system was complete, and the lower Mississippi was effectively separated from what had been its flood plain. The levees protected settlements along the river from catastrophic flooding — but they also channeled the rich sediment that had historically replenished the delta plain into the Gulf of Mexico. [Image credit: Coastal Sustainability Studio]
Building the levees Crews transform the natural river edge into a controlled levee. The construction of the levees anchored in place what had once been the dynamic, flexible banks of the river. [Image credit: Public Library of Cincinnati and Hamilton County.]
Perceiving the river What was once a highly dynamic and variable natural system became, in a few decades in the mid 20th century, one of the world’s most complex feats of engineering. The single-minded pursuit of flood protection and efficient navigation transformed as well how the river was perceived by the generations that followed. [Image credit: Left: Fisk, 1944. Map of ancient courses of the Mississippi River, Cape Girardeau, MO – Donaldsonville, LA. Plate 22-10. Right: America's Wetland Resource Center.]
20th-century wetland loss Without the continual replenishment of sediment from the Mississippi River, the Louisiana Delta has since 1930 lost 2,300 square miles of wetlands due to the combined effects of levee construction, land subsidence, storm damage, canal dredging and hydrocarbon extraction. [Image credit: Coastal Sustainability Studio]
Human habitation and infrastructure Continued land subsidence and sea level rise is imperiling Louisiana coastal communities. A 2009 report, by LSU scientists Michael Blum and Harry Roberts, integrates projections on sea level rise and land subsidence to predict a devastating loss of the deltaic wetlands over the course of this century. This could put many communities in danger of being inundated and force a mass relocation. [Image credit: Coastal Sustainability Studio]
Giving the river room To return the river to its historic function of building and maintaining the delta and coastal landscapes, the CSS proposes a river-wide system of controlled flooding through large-scale river diversions. This is not a strategy of retreat: this proposal works hand-in-hand with a series of urban, landscape and architectural design strategies that challenge us to engage the processes and potential benefits of a more naturalized river system. [Image credit: Coastal Sustainability Studio]
Constructing with water Coastal protection and restoration must start with the Mississippi River. The costs associated with highly engineered flood protection and shipping channels — with dredging, pumping, pouring concrete, and dumping stone — are becoming insupportable. We propose a series of 5 large river diversions to distribute sediment to the 5 major historic river basins: thus the power of the river itself to build up land is harnessed. But because of the many communities, industries and farms currently located along the river, these diversions will use both hard and soft infrastructures. The wetland buffer that once separated open water and settlement will be recreated with the goal of supporting 21st-century cities and towns as well as restoring the natural coastal ecology. Today the flow volume of the river is highly controlled. One-third of the Mississippi, for instance, is diverted into the Atchafalaya River, as mandated by Congress after the Great Flood of 1927. Further downstream other Army Corps-constructed diversions, at Morganza and Bonnet Carré, ensure that no more than 1.2 million cubic feet per second travels to the City of New Orleans. Our CSS proposal augments these diversions to capture sediment from the river during flooding and deliver it to where it is most needed. [Image credit: Coastal Sustainability Studio.]
Pulsed flooding through sediment diversions Today the flow volume of the river is highly controlled. One-third of the Mississippi, for instance, is diverted into the Atchafalaya River, as mandated by Congress after the Great Flood of 1927. Further downstream other Army Corps-constructed diversions, at Morganza and Bonnet Carré, ensure that no more than 1.2 million cubic feet per second travels to the City of New Orleans. Our CSS proposal augments these diversions to capture sediment from the river during flooding and deliver it to where it is most needed. [Image credit: Coastal Sustainability Studio]
The deteriorating natural defense of New Orleans The cutting of shipping canals has had devastating environmental effects on New Orleans, especially for the Ninth Ward and St Bernard Parish. These areas have always been particularly vulnerable to flooding due to their low elevation and proximity to open water. The saltwater intrusion brought about by the construction of the 76-mile-long Mississippi River Gulf Outlet in the mid 20th century killed much of the cypress forest that had protected the area from storm damage. MRGO was closed in 2009. Currently these neighborhoods are protected only by a network of man-made levees and by constant pumping. [Image credit: Coastal Sustainability Studio]
Bayou Bienvenue: ghost forest The cypress forest that once protected the city from storm surges was extensive, encompassing 30,000 acres. Since the construction of the MRGO, the entire forest has died and turned to open water. The sea wall visible in the background was built after Hurricane Betsy, in 1965, and protects the Lower Ninth Ward. Unfortunately, the wall also severed the neighborhood from the bayou, where residents once trapped and fished in the rich wetlands. [Image credit: Coastal Sustainability Studio]
Strategies for rebuilding the region with the river The Central Wetlands Unit — which refers to the 30,000 acres of former marsh degraded by MRGO — is an essential part of the future defense of New Orleans and St. Bernard Parishes. Through a combination of soft and hard infrastructural systems, the CSS proposes the development of a new marsh. Part cypress forest, part wastewater treatment facility, part regional park, this new marsh would harness the river's power to serve the 21st century city. [Image credit: Coastal Sustainability Studio]
The struggle to return The Lower Ninth Ward suffered especially extensive damage — and many deaths — from the post-Katrina flooding caused by the failure of the Industrial Canal, which passes through the area. Five years later the neighborhood is still struggling to rebuild. [Image credit: via UW NOLA, photograph by Andrew Leaf]
Lost wetland buffer The coastal wetlands have been degraded along their land as well as coastal sides. Before the era of large-scale engineering and continuous pumping, human settlement was confined to the areas above sea level. Early 20th-century technological advances, such as the screw pump, made it possible to drain the wetlands; the postwar housing boom of mid-century made it economically feasible. The result is an uneasy junction between open water and suburban development. [Image credit: Coastal Sustainability Studio]
Strategies for return This matrix shows some of the ways in which the CSS is re-imagining Lower Ninth Ward. These scenarios are based on investment in housing, neighborhoods and recreation. [Image credit: Coastal Sustainability Studio]
Envisioning the Ninth Ward Our design is driven by the concept of a robust wetland zone that supports a resilient natural environment alongside sustained human settlement. The northern part of the Lower Ninth is transformed to optimize its location on the water's edge. Dense housing and community buildings are concentrated in infrastructural corridors; schools and other institutions benefit from the wetland. Large open spaces provide opportunities for urban agriculture and stormwater retention. [Image credit: Coastal Sustainability Studio]
Renewing the wetland The wetland is neither a void nor a separator but a rich locus for a new kind of neighborhood — one that builds on the long Louisiana tradition of living with water. [Image credit: Coastal Sustainability Studio]
Lower Ninth Ward farmer's market Claiborne Avenue has traditionally been a separating corridor, dividing those areas above and below sea level, and separating the more urban and rural areas. In our proposal Claiborne Avenue once again becomes a threshold, now between different types of dwellings. To the south the neighborhood is densified; to the north the space between infrastructural corridors is given over to farmland and open space for recreation and stormwater retention. A farmer's market would become an important neighborhood hub, linking the productive landscape of the Ninth Ward to the urban consumers of New Orleans and the region beyond. [Image credit: Coastal Sustainability Studio]
Bayou Bienvenue boardwalk Saltwater intrusion has not only killed off the cypress forest but also increased land subsidence. The western section of Bayou Bienvenue has sunk significantly and now forms an area of open water of roughly 400 acres. This is potentially a recreational amenity for fishing, birding, kayaking, canoeing, sailing, and crabbing. The boardwalk is located on the wetland side of the levee and connects to the neighborhood at several points. [Image credit: Coastal Sustainability Studio]
Farming the Ninth Returning the vacant land of the northern Lower Ninth to productive use was a major focus of the CSS. A mix of backyard planting, community gardening and commercial farming are all ways to use flood-prone land that would be risky to resettle densely. In our proposal, Galvez Street, shown here, would accommodate both small farm cottages to the south and larger commercial operations to the north. [Image credit: Coastal Sustainability Studio]
Neighborhood corridors Historically Tennessee, Caffin, and Tupelo Streets extended into the wetlands to the north. Our proposal concentrates redevelopment on these three corridors while encouraging only a limited footprint in flood-prone areas. Housing and commercial space along these streets are elevated to withstand flooding with minimal damage. The ground floors accommodate parking, storage and studios, as well as ample space for social gathering. [Image credit: Coastal Sustainability Studio]
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