Jack Ruff
Bill Sherman
ARCH 3120
November 26, 2019
Water Management in New Orleans: Ecology as Infrastructure
Situated on a swath of low-lying land bordered by Lake
Pontchartrain to the north and the Mississippi River to the south
(see Figure 1), the city of New Orleans is extremely vulnerable to
the threat of flooding. On August 29, 2005, Hurricane Katrina
exposed this vulnerability, inundating the city with heavy rainfall
and storm surges that resulted in the collapse of the city’s
artificial levees.[footnoteRef:1] Massive flooding ensued (see
Figure 2), killing nearly 2000 people and causing an estimated $100
billion dollars in damage.[footnoteRef:2] [1: History.com Editors,
“Hurricane Katrina,”
https://www.history.com/topics/natural-disasters-and-environment/hurricane-katrina,
(November 9, 2009).] [2: Ibid. ]
Figure 1: A Map of New Orleans showing its situation between
Lake Pontchartrain to the north and the Mississippi River to the
south.
https://www.google.com/maps/place/New+Orleans,+LA/data=!4m2!3m1!1s0x8620a454b2118265:0xdb065be85e22d3b4?sa=X&ved=2ahUKEwjCrv7n3ojmAhUjT98KHXwvDd0Q8gEwAHoECA0QAQ
As the effects of Climate Change progress, New Orleans is
becoming increasingly vulnerable to the threat of flooding. The
existing infrastructure of the city is ill-equipped to respond to
the rising sea levels and the increased frequency of extreme
weather events that accompany climate change. This paper aims to
examine the ecological and infrastructural history of the city of
New Orleans in relation to the heightening effects of climate
change in an effort to generate an ecology-based infrastructural
strategy that would bolster the resilience of the city in the event
of flooding. The paper will begin with an exploration of the
ecological and infrastructural history of the city, followed by an
analysis of the primary threats posed by climate change. Then, this
information will be considered in the development of an
ecology-based infrastructure plan addressing water management in a
city increasingly threatened by flooding.
Figure 2: This image shows the extent of the flooding and the
damage it caused in New Orleans. Many houses are submerged.
https://www.pri.org/stories/2015-09-14/new-orleans-still-vulnerable-another-big-storm
The ecological history of New Orleans is closely linked to its
infrastructural history. The ecology of the city can be traced back
to the Ice Age, when runoff from melting glaciers carried sediment
down the Mississippi River to the Gulf of Mexico. Approximately
7200 years ago, the mouth of the river began to press seaward,
resulting in the large-scale deposition of these sediments by the
tides and currents at the mouth of the river. The gradual
accumulation of these sediments resulted in the formation of mud,
constituting the emergence of Louisiana from the Gulf Shore. The
areas closest to the Mississippi River rose the highest in
elevation, as they accumulated higher deposits of sediment. Areas
farther from the Mississippi River received just enough sediment to
rise above sea level, resulting in the formation of swamps. The
areas farthest away from the Mississippi River received the
smallest deposits of sediment, resulting in the formation of grassy
wetlands and saline marshes.[footnoteRef:3] Thus, the coastal
low-lying area in which the city of New Orleans would develop was
defined by a triad of ecological conditions: elevated land masses
along the banks of the river, swamp lands farther out from the
river, and marshes in the outer regions. [3: Richard Campanella,
“How Humans Sank New Orleans,”
https://www.theatlantic.com/technology/archive/2018/02/how-humans-sank-new-orleans/552323/),
(February 6, 2018). ]
This ecological diversity would prove to be crucial in defining
the infrastructural development of the city. The native peoples
that originally inhabited the area around New Orleans tended to
adapt to the fluidity of these ecologies, simply moving to higher
lands in the event of flooding. However, with the arrival of the
Europeans in the 18th century, this dynamic relationship with the
land was replaced by a focus on settlement. In 1718, the French
settlers established the city of New Orleans on “two narrow strips
of land” along the Mississippi River.[footnoteRef:4] The strips of
land were natural levees, the first of the three ecologies that
defined the area. Between ten and fifteen feet above sea level, the
strips of land were surrounded by swamps and marshland (see Figure
3). For the first two centuries following the founding of the city,
urban expansion and development were confined to these two strips
of land. As a result, much of the city’s urbanization,
architecture, and infrastructure were informed by this underlying
topography.[footnoteRef:5] This can be seen in the situation of the
French Quarter, the historic core of the city, along the bank of
the Mississippi River. [4: Ibid.] [5: Ibid. ]
Figure 3: This map shows the French Settlement of New Orleans
along the bank of the Mississippi River. It also outlines the
relationship between the elevated land masses along the bank of the
river and the swamps and marshes in the outlying regions.
https://www.pinterest.com/pin/277041814564334426/?lp=true
In the 1800’s, the city of New Orleans began to expand out from
the initial levee on which it was founded. Citizens began to create
embankments along the river composed of parcels of land that
directed water back to the swamp via a network of drainage ditches.
Outflow canals were dug to increase the efficiency of drainage to
the swamp and neighboring plantations utilized ditches to control
the concentration of water in the soil. For many of the initial
water projects, gravity was the main source of energy. But early on
in the century, steam power was introduced as a technology that
could strengthen the city’s drainage system. In 1893, the city
enlisted a team of expert engineers to figure out how to create a
comprehensive drainage system that was more effective. After
producing a detailed topographic map of the city, they found that
some areas within the city were actually below sea level. The cause
would eventually be understood as anthropogenic soil subsidence,
the sinking of land as a result of human action. When runoff is
removed and artificial levees prevent the river from overtopping,
the level of the groundwater lowers and the soil above it dries
out.[footnoteRef:6] Compounded by the decomposition of organic
matter in the soil itself, this results in the formation of air
pockets in the soil. As these pockets are filled in by sediment,
the ground actually sinks. [6: Ibid. ]
By 1905, the city was serviced by forty miles of canals,
hundreds of miles of pipelines and drains, and six pumping stations
(See Figure 4). The system could pump out 5,000 cubic feet of water
per second. As the twentieth century progressed, the city expanded
into the surrounding swamp land that had been “conquered” by the
city’s infrastructure.[footnoteRef:7] But as the city expanded into
the subsided areas that were continually serviced by the city’s
drainage system, the subsidence only worsened. Subsided communities
were lined with artificial levees and floodwalls. By 1935, only
seventy percent of the city was above sea level.[footnoteRef:8] [7:
Ibid. ] [8: Ibid. ]
Figure 4: This image shows one of the city’s massive canals and
one of the pumps.
https://www.daniels.utoronto.ca/work/research/gutter-gulf
When Hurricane Katrina made landfall in August of 2005, the
sunken elevation of much of the city compounded with the inadequacy
of its water management infrastructure resulted in the massive
flooding that wreaked havoc on the city. One of the primary
weaknesses of the drainage system was the network of canals. The
walls of the canals had been constructed on top of the original
marsh soil with layers of compacted clay above it to reinforce the
wall. When the canals filled up during the storm, the connection
between the marsh soil and the clay layers above it proved to be
too weak and the water pressure from within the canal blew out the
walls at this boundary.[footnoteRef:9] The destruction of Hurricane
Katrina highlighted the inability of artificial infrastructure to
protect a city like New Orleans, rooted in coastal water ecologies
of rivers, swamps, and marshes, from extreme flooding events. [9:
Chris Reed, Nina-Marie Lister, and Jane Wolff, PROJECTIVE
ECOLOGIES, (BARCELONA: ACTAR, 2019).]
In order to explore ecology-based design solutions that could
help New Orleans adapt to future flooding events, it is imperative
to understand the increasing impacts of climate change on the city.
The primary drivers of climate change that contribute to flooding
events in coastal areas are relative sea level rise (RSLR), severe
storms, and changes in wind and wave behaviors. Relative sea level
rise is the result of the thermal expansion of water in the oceans
and the additional volume of meltwater from glaciers, ice caps, and
ice sheets in Greenland and Antarctica.[footnoteRef:10] This rise
in sea level is a serious threat to the city of New Orleans in its
potential erosion of the coastlines that act as a barrier between
the city and storm surges. Additionally, the rising sea level could
contribute to the flooding of the Mississippi River. Both of these
effects heighten the potential severity of flooding in New Orleans
in the future. [10: Christopher B. Field, Climate Change 2014:
Impacts, Adaptation, and Vulnerability, (Cambridge: Cambridge
University Press, 2015).]
Severe storms, such as tropical cyclones and extratropical
cyclones, can generate storm surges in coastal areas. Since the
1970s, there has been an increase in the frequency and intensity of
the strongest tropical cyclones in the North Atlantic. Coupled with
projected increases in heavy precipitation events in the future,
storm surges exist as a serious threat to the city of New
Orleans.[footnoteRef:11] The storm surge of Hurricane Katrina
played a large part in the overwhelming of the infrastructure,
chiefly the destruction of the canal walls. With projected
increases in the frequency and intensity of severe storms, New
Orleans is extremely vulnerable as a low-lying coastal city. [11:
Ibid. ]
In addition to relative sea level rise and severe storms, wind
and wave behaviors pose a credible threat to the city of New
Orleans with respect to flooding events. Changes in wind climate,
as a result of global increases in average atmospheric temperature,
affect large-scale wave climate. Energy dissipation as a result of
the breaking of waves on shorelines contributes to elevated coastal
sea levels through both wave setup and beach erosion. As a result,
changes in wind and wave climates affect sediment dynamics in
coastal areas. Additionally, these patterns can harm coastal
populations with increased storm surges and
flooding.[footnoteRef:12] In the case of New Orleans, situated
along the Mississippi River close to the Gulf of Mexico, these
patterns heighten the effects of flooding on the city and its
population. [12: Ibid. ]
With an established understanding of the ecological and
infrastructural history of New Orleans and the threats posed to the
city by climate change, speculation into ecology-based design
solutions to develop the city’s resilience with respect to flooding
events can be conducted. The devastation waged by Hurricane Katrina
on the city of New Orleans outlined the inability of artificial
infrastructure to protect the city from extreme flooding events. As
the effects of climate change progress, the potential for extreme
flooding events in the city will only heighten. Thus, it is clear
that infrastructural alternatives for New Orleans need to be
centered in the pre-existing ecologies of the region: the elevated
land masses along the banks of the river, the swamp lands farther
out from the river, and the marshes in the outlying areas.
The formation of the swamps and marshes was a direct result of
the situation of the area within the convergence of the Gulf of
Mexico and the Mississippi River. In times of flooding, the swamps
and marshes served as a natural network of green infrastructure to
collect excess water, preserving the elevated land masses. The
expansion of New Orleans from the initial strips of land along the
river to the surrounding swamp lands resulted in the destruction of
this natural infrastructure. While the drainage system devised by
the city has proven effective in day-to-day drainage, the reality
is that the destruction of the pre-existing swamp land cannot be
offset by a series of canals and pipelines. In order to create a
city that can adapt to extreme flooding events, the current
artificial infrastructure needs to be combined with a system of
green infrastructure.
In the process of retrofitting the existing infrastructure of
New Orleans with a new system of green infrastructure, OMA’s
Resist, Delay, Store, Discharge: A Comprehensive Water Plan for
Hoboken provides strategies and frameworks that are useful in
consideration of a hybrid infrastructural system. The project
proposes an urban water management strategy for the coastal city of
Hoboken, New Jersey, which was devastated by Hurricane Sandy in
2012. The communities of Jersey City, Hoboken, and Weehawken were
particularly susceptible to storm surges and flash floods. The plan
proposes a strategy of “Resist, Delay, Store, Discharge” for the
city of Hoboken (See Figure 5). The “Resist” component is composed
of a combination of hard infrastructure and soft landscapes for
coastal defense. The “Delay” component provides policy
recommendations, guidelines, and urban infrastructure to slow
rainwater runoff. The “Store” component advocates for a circuit of
interconnected green infrastructure to store and direct excess
rainwater. Finally, the “Discharge” component utilizes water pumps
and alternative routes to support water drainage.[footnoteRef:13]
[13: Mohsen Mostafavi and Gareth Doherty, Ecological
Urbanism, (Zürich: Lars Müller Publishers, 2016).]
Figure 5: An axonometric view of OMA’s four-part water
management strategy for the city of Hoboken, New Jersey: Resist,
Delay, Store, Discharge.
https://oma.eu/projects/resist-delay-store-discharge-comprehensive-urban-water-strategy
In the generation of an ecology-based infrastructure plan aimed
at increasing the resilience of New Orleans in the event of
flooding, there are two primary features of OMA’s Resist, Delay,
Store, Discharge: A Comprehensive Water Plan for Hoboken that could
strengthen a plan for New Orleans. The first feature is the hybrid
nature of the water management plan: hard infrastructure and green
infrastructure are synthesized to create a dual defense system
along the shore. In the context of New Orleans, this precedent of
hybrid infrastructure is helpful in considering the ways in which
the existing infrastructure of the city is incorporated into an
updated ecology-based system. The second feature of OMA’s plan for
Hoboken is the diversity of water management strategies that are
employed. Not only does the plan utilize numerous forms of water
management infrastructure, from hard infrastructure along the shore
to soft landscapes within the city, but it also positions these
infrastructures such that they act as multiple lines of defense. If
employed in New Orleans, the diversity of these water management
strategies would strengthen the resilience of the city by providing
multiple approaches to flood mitigation. The diversity of these
strategies ensures that if one form of infrastructure fails, such
as the canals in the case of Hurricane Katrina, another form of
infrastructure can respond and prevent the entire system from
failing.
With the aim of strengthening the resilience of the city with
respect to flooding, I would propose a three-part plan to retrofit
the existing infrastructure of New Orleans with an ecology-based
infrastructure. The first part prioritizes the defense of the
city’s shoreline boundaries, utilizing a combination of hard
infrastructure and soft landscapes. The second part is centered on
the modification of existing spaces within the city to create an
expansive network of green infrastructure. The third part focuses
on the integration of this green infrastructure with the existing
water management infrastructure to effectively store and discharge
water.
The defense of the city’s shoreline boundaries would consist of
two primary defenses: an outer shell of hard infrastructure and an
inner band of soft landscapes. The hard infrastructure would take
the form of a habitable levee, a series of raised platforms along
the Mississippi River and Lake Pontchartrain providing venues for
public activities and protection from flood waters. Within this
outer defense, a band of soft landscapes functioning as shoreline
parks would encircle the city, assisting the habitable levees in
creating spaces for public interaction while aiding in the
absorption of potential floodwaters. Figure 6 illustrates the
sectional relationship between the habitable levee bordering the
water and the soft landscape within.
Within the city itself, existing spaces would be modified to
produce an expansive network of green infrastructure. This network
of green infrastructure would be composed of landscapes referencing
the native ecologies of the city: the elevated land masses, the
swamp lands, and the marshes. The medians of major roads, such as
Napoleon Avenue and Jefferson Avenue, would be replaced with sunken
strips of green infrastructure aiding in the storage and discharge
of excess stormwater. Functioning like a marsh, these strips would
consist of depressions filled with waterlogged grasses (See Figure
7). In the event of heavy rainfall or flooding, these channels
would collect surplus water and redirect it to larger canals and
pump systems.
Figure 6: The section above shows the elevated mass of the
habitable levee bordering the Mississippi River. Within this outer
shell, a band of soft landscapes serves as a second line of defense
by absorbing excess water.
Figure 7: This section illustrates the sunken nature of the
median marsh with respect to each lane of Napoleon Avenue.
Additionally, parks and open spaces would be converted to hybrid
landscapes of elevated land masses, swamps, and marshes,
facilitating public accessibility while storing and redirecting
water in the city. While the city has a number of larger parks with
hybrid landscapes, such as City Park and Audubon Park, these exist
as outliers within the dense urban grid of the city. By integrating
these hybrid landscapes into and throughout the existing fabric of
the city, water retention and discharge would be significantly more
efficient.
Further, the existing canals within the city would be updated to
fit within this network. The concrete walls of the canals would be
replaced with elevated embankments of compacted soil. Lined with an
array of grasses and trees, these embankments reference the native
ecologies of swamps and marshes, mitigating the severity of
flooding along the canal by absorbing excess water. The canals
become axes of public interaction, with the embankments doing
double duty as park spaces and green infrastructure.
To help spur the creation of this green infrastructural network
within the city, policy would be introduced that incentivizes the
creation of green roofs and localized green infrastructure projects
with tax credits. This would provide an opportunity for green
infrastructure to reach the densest parts of the city where a lack
of urban real estate makes large-scale green infrastructure
projects difficult.
The integration of the green infrastructure with the existing
infrastructure of the city hinges on the specific roles of each
water management strategy in storing or discharging excess water.
Many of the green infrastructures, including the median marshes,
hybrid landscapes, and green roofs, are tasked with the storage of
excess water, ultimately delaying extreme flooding events. Many of
the existing infrastructures, including the updated canals and the
network of pipelines and pumps, are tasked with the discharge of
excess water, redirecting this water out of the city. Thus, these
infrastructures work together to store water, ultimately preventing
flooding in the short term, and to discharge water, ultimately
preventing flooding in the long term.
By utilizing a variety of water management strategies and
positioning them throughout the city, my proposal for an
ecology-based infrastructure in the city of New Orleans bolsters
the resilience of the city by providing a multifaceted response to
the threat of flooding. The shoreline defense of habitable levees
and soft landscapes acts as the first line of defense against
external flooding, while the internal hybrid network of green and
hard infrastructure mitigates the effects of flooding by storing
and discharging excess water. Engaging with the native ecologies of
the region, the introduction of green infrastructure into the
existing infrastructure of the city allows for a more effective
response to flooding.
One of the primary challenges in retrofitting the existing
infrastructure of the city of New Orleans lies in the integration
of this infrastructure into the cultural and historical fabric of
the city. While a return to native ecologies is the best strategy
in developing a green infrastructure for the city, the reality is
that much of the city has been built upon artificial land that
replaced these ecologies. Thus, the infrastructure of the city must
engage with these native ecologies where it can: along roadways, in
existing parks, in vacant lots. In my proposal, the
often-overlooked margins of space within the city become
opportunities for the resurgence of these native ecologies within
the existing cultural framework. This allows for the preservation
of the city’s cultural identity and architectural history amidst
the transformation of its infrastructural system.
With the increasing effects of climate change, New Orleans’
position as a low-lying coastal city renders it particularly
vulnerable to extreme flooding events. Accompanying the urban
expansion of the city, the degradation of native coastal ecologies
that served as natural water management infrastructures has
heightened this vulnerability. The devastation of Hurricane Katrina
outlined the importance of utilizing native ecologies in the
infrastructure of the city. As the city of New Orleans looks to the
future, a water management infrastructure based on these native
ecologies is essential in maintaining the resilience of the city
with respect to flooding. Thus, I am proposing a three-part plan to
retrofit the existing infrastructure of New Orleans with an
ecology-based infrastructure. The first part prioritizes the
defense of the city’s shoreline boundaries, utilizing a combination
of hard infrastructure and soft landscapes. The second part is
centered on the modification of existing spaces within the city to
create an expansive network of green infrastructure. The third part
focuses on the integration of this green infrastructure with the
existing water management infrastructure to effectively store and
discharge water. By engaging with native ecologies while preserving
the cultural identity of the city, this plan provides a sustainable
solution to the threat of extreme flooding events in New
Orleans.
Bibliography
Campanella, Richard. “How Humans Sank New Orleans.” The
Atlantic. Atlantic Media Company, February 6, 2018.
https://www.theatlantic.com/technology/archive/2018/02/how-humans-sank-new-orleans/552323/.
Field, Christopher B. Climate Change 2014: Impacts,
Adaptation, and Vulnerability. Cambridge: Cambridge University
Press, 2015.
History.com Editors. 2019. “Hurricane Katrina.” HISTORY. March
13, 2019.
https://www.history.com/topics/natural-disasters-and-environment/hurricane-katrina.
Mostafavi, Mohsen, and Gareth Doherty. Ecological Urbanism.
Zürich: Lars Müller Publishers, 2016.
Reed, Chris, Nina-Marie Lister, and Jane Wolff. PROJECTIVE
ECOLOGIES. BARCELONA: ACTAR, 2019.
