moloney ethics artificial levee breaches - fort myers, florida · since the late 1700s, ... the...

GEOTECHNICAL ENGINEERING

Aquila: The FGCU Student Journal Vol. 1 2014

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Abstract — Levees are a common solution to prevent flooding. These earthen slopes constrict rivers, protecting nearby lands. Overtime, the river becomes constricted, unable to expel excess water to tributaries, causing more severe floods. Levee construction builds higher and steeper slopes, forcing stronger and more devastating floods. Before human intervention, rivers flooded plains, supplying the ecosystem with nutrients. After the major flood of 1927 along the Mississippi River, the U.S. Army Corps of Engineers decided to revert to floodways to divert floods. This process has relieved some pressure at key cities, such as New Orleans, LA and Cairo, IL. It has also proved successful at reviving the depleting riparian forests in California along the Cosumnes River. Some of the designated floodplains, such as the Birds Point-New Madrid Floodway near Cairo, IL, contain farmland along with residents. Although the original homeowners have received compensation for the land, farmers judge detonating levees to divert floods into their fields as unjustified. Some of the blame has landed upon engineers. The only unethical issue lies in the government promising compensation to individuals and not following through. The U.S. Army Corps of Engineers and their over-designed plans do not hold sole responsibility for destruction caused by activating the Birds Point-New Madrid Floodway today, as approval and easements payments began in the 1930s. The floodways designate floods higher than one that would occur during a hundred-year-storm, accounting for a factor of safety. Homeowners and farmers are aware of the intended use of their land. Residents should take encouragement from leaving current and future floodplains during this transition from levees to a more natural floodway system.

Index Terms— levee destruction, intentional levee breach, engineering ethics, Birds Point-New Madrid Floodway

I. INTRODUCTION ESTRUCTION can sometimes provide the solution to prevention. For instance, removing current flood

preventive measures may actually decrease flood concerns. Flooding is a major concern to any city located near a river. Some engineers conclude that the natural environment provides the best flood control; the optimal plan for flood prevention focuses on removing previous flood infrastructure. Constructing levees, a soil embankment next to a waterway, previously provided the ultimate solution to limit floods. While providing a barrier between rivers and property, levees can drastically change the neighboring ecosystems, the ground water level, and increase stream flow and flood levels. Reasons to artificially breach a levee include preventing floods downstream, relieving pressure upstream, and reviving natural floodplains. This paper will focus on the ethics of intentional levee breaches, using the Birds Point-New Madrid Floodway of the Mississippi River as the primary area of focus.

Since the late 1700s, during the early settlers, people have tried to control the periodic floods on the Mississippi River. Lands that once consisted of natural floodplains now contain

homes and farmlands. To control unwanted flooding, the U.S. Army Corps of Engineers took charge of building levees to contain the river. Rising river levels and large storm events add stress to levees downstream. The U.S. Army Corps developed plans to reduce the chances of disastrous flooding, especially after events such as the 1927 flood, Hurricane Katrina, and the 2011 flood. In some cases, the best course of action may involve destruction. In 2011, the U.S. Army Corps detonated a section of levees in Birds Point, Missouri to induce flooding in farmland as well as almost one hundred homes, protecting almost 3,000 residents downstream. This event illustrates the difficult situation some engineers have to face in choosing “the lesser of two evils” and the reality in executing the ultimate best-case scenario. Details surrounding the detonation of 2011 will primarily aid the exploration of this topic. The discussion will include the levee destruction along with two other intentional levee breaches.

There are many reasons to detonate, remove, or abandon river levees. Engineers intentionally breached a levee near Cairo, Illinois, to prevent flooding of the populated city, inundating farmland and homes in a separate area. Detonating levees in 1937 flooded Caernarvon, Louisiana. This event caused flooding to poor districts to protect New Orleans. In California, abandoned and unmaintained levees exist along the Cosumnes River. This resulted in a successful environment rejuvenation project as well as a flood prevention measure.

Ethics of Artificial Levee Breaches Francesca L. Moloney

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Fig. 1. Flood stages for Chester, Illinois and Vicksburg, MS along Mississippi River for past 1000 years with major flood events noted (Pinter et al. 2006)., with locations shown adjacent to the graphs.

1937 flood

1937 flood

1927 flood

1927 flood

Fig. 2. Levees and floodways present along the Mississippi River as of 2011 (Henze 2011).



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II. MISSISSIPPI RIVER LEVEES

A. Background The Mississippi River is susceptible to periodic flooding.

Native Americans told the first European explorers, in the late 1700s, that the river floods approximately every fourteen years (PBS 2010). Nevertheless, farmers planted crops in the rich alluvial soils by the river and builders constructed cities. Figure 1 shows the flooding trends of the Mississippi River. It is evident that major flooding occurred approximately every 5-10 years since before 1900 (Pinter et al. 2006). To combat flooding, the Mississippi River Commission began work in 1879 to implement flood control plans. The commission commenced a “levees only” policy in 1885. The U.S. Army Corps of Engineers constructed levees up and down the Mississippi River, aiming to seal off outlets and force floods to disperse downstream quickly. However, the levees forced the river to rise higher as it contained and restricted its flow requiring levees’ build-up to increase even further. Levees constructed in 1850 eventually totaled a height over five times that of the original requirement (PBS 2010).

The 1927 flood became a pivotal event in the development of Mississippi River flood control. A year of endless storms with high precipitation bombarded the Mississippi River Basin, filling each tributary to capacity. By the spring of 1927, levees began to fail. Up until this point, levees offered the primary flood control structure. Damages suffered during the 1927 flood totaled $15.7 million (Trotter et al. 1998). This flood showed that levees did not perform as expected. This event sparked the implementation of floodways.

Floodways encompass any location into which a river flows when it exceeds the height of its banks. Absent human control, a river will overflow during floods and leave rich sand deposits. This provides woodlands, wetlands, plants, algae, and other organisms with nutrients. Floodways are a natural replacement for levees that typically trap and centralize water in one location, increasing floods. After the flood of 1927, the U.S. Army Corps of Engineers provided a solution to redirect excess water into five floodways: the Boeuf floodway in Arkansas, the Birds Point-New Madrid floodway near Cairo, IL, and the Bonnet Carré and West and East Atchafalaya floodways north of New Orleans, Louisiana. Figure 2 depicts these floodways. Backwater areas and floodways surround Vicksburg, Mississippi to the north and south. If the use of floodways aims at reducing flooding, then river levels should decrease after construction. Figure 1 depicts exactly this at Vicksburg. The maximum river stage began decreasing after hitting peak in 1927. The flooding at Cairo, Illinois, however, increased. Cairo sits at the junction of the Ohio River and Mississippi River. In the 1920s, Cairo residents totaled 3,000 people. Following the priority of the protection of residents, engineers built up levees near the city, with the Birds Point-New Madrid Floodway allocated to the south. River flow may have increased due to the extra levees that further constricted the flow from both rivers. The only intentional utilization of the floodway occurred in 1937 and 2011.

B. Birds Point-New Madrid Floodway The Birds Point-New Madrid Floodway was one of the first

supplementary, permanent projects to the levee system. Its

design protects Cairo, Illinois. The floodway provides an area for the flooding river to occupy during flood stages. The system contains four main components: a front-line levee system, setback levees, fuse plugs, and the floodway itself. According to Figure 3, the inflow Crevasse at the Upper Fuse Plug, indicated by the black line, allows the floodwaters to inundate the floodplain. Restricted by the setback levee, the flood waters can reenter the Mississippi River further downstream at Crevasse #1 and #2, depicted by the red block, at a controlled rate (Mississippi River Commission a). This allows for river draining to occur upstream as well as preventing major flooding downstream of Cairo.

The fuse plugs are sections of shorter levees that risk natural and intentional breaching. This allows the river to flow naturally into the floodway during a flood event while protecting the floodway during river fluctuations from the average storm event. During a flood warning, at the time of an already swollen river, detonated the fuse plugs can occur before reaching the flood stage. For ease of detonation, the design buries polyethylene pipes into the fuse plugs. Engineers can direct explosives and fill these pipes in less than a day. If detonation is not necessary, the pipes allow for the safe removal of the blasting agents (Mississippi River Commission a). This innovative design allows more control over river overflow in comparison to the river’s historical and natural conditions. The most crucial aspect in the design of the river control, however, is the flood stage.

C. Project Design Flood Design criterion is necessary to analyze levees and indicate

when to open the floodway. The “project design flood” dictates an appropriate design flood stage in the Lower Mississippi River. Storms and floods calculations mark certain return periods for various locations. A hundred-year-storm, for instance, has a one-percent chance of occurring in any one year. But designing for a hundred-year-storm proves inadequate for the Lower Mississippi River. A hundred-year-flood does not always coincide with a hundred-year-storm. Multiple strong storm events occurring in centralized locations may result in massive flooding, as did occur during the 1927 flood. The ultimate combination of potential storms with realistic orientations, intensities, and locations yields the project design flood. It consists of three massive storms from 1937, 1938, and 1950 that preceded large flood events in the Lower Mississippi River. The three storms, with varying characteristics, became the largest recorded precipitation events on the river. Models of these storms showed them as occurring at various times and locations, to optimize the precipitation landing in the tributaries leading to the Mississippi River. The largest project design flood resulted in the 1937 storm striking first, followed by the 1950 storm three days later, and finished with the 1938 storm occurring an additional three days later (Mississippi River Commission). Figure 4 shows a typical section at Cairo, Illinois, detailing the hundred-year-flood. This flood projection has an elevation of 330.770 feet while the project design elevation lists three feet more. The elevation of the levee is at 334.263 feet, allowing for less than a foot of freeboard between the project design flood and the top of the levee at Cairo (Mississippi River



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Commission b). The Mississippi River Commission developed this rain event in 1956. Planners developed this model with methods still accurate today, accounting for a flood about twenty-five percent greater than the 1927 flood (Mississippi River Commission b). The U.S. Army Corps of Engineers along with the Mississippi River Commission use the project design storm to design and adjust flood control plans and projects, specifically floodplains.

D. Birds Point-New Madrid Floodway Intentional Breaches

Engineers activated the Birds Point-New Madrid floodway for the first time in 1937. During the Great Flood of 1937, the flood stage surpassed record elevations at Cairo, Illinois. This case is distinct from the other two, as water had already begun to spill over into the floodway before explosions occurred. The U.S. Army Corps of Engineers attempted to breach the upper fuse plug with shovels on January 23rd but turned to explosives the next day after little result. Natural breaches in the frontline levee of the floodway in addition to backwater flooding would have caused major flooding in the floodway if the U.S. Army Corps of Engineers left the fuse plugs alone (Mississippi River Commission a).

At the time, 3,000 residents lived in the Birds Point-New Madrid floodway region as opposed to 200 people in 2011 (Fox News). The intentional breaching of two levees added floodwaters to the floodway as it diverted a quarter of the flood flow experienced at Cairo. The chief of engineers, Maj. Gen. Edward Markham, announced that while the use of the floodway proved successful, he believed “that no plan is satisfactory which is based upon deliberately turning floodwaters upon the homes and property of people, even though the right to do so may have been paid for in advance” (Mississippi River Commission a). This demonstrates that there is not always one foolproof, universal plan. In this case, the 3,000 residents received more floodwaters to prevent flooding in Cairo.

Engineers activated the floodway only on one other occasion. In April 2011, river levels reached 18.811 m (61.72 ft.) at Cairo, Illinois. To relieve the town, located at the convergence of the Ohio and Mississippi Rivers, a crew artificially breached the upper fuse plug. A federal judge approved the action on April 29, 2013 (Fox News 2011). The breach spanned a total length of two miles. Water rushed into the floodplain, flooding 90 homes and 130,000 acres of land. This event caused the river to successfully lower almost four feet (Bury et al. 2011). The last two levee breaches occurred at Inflow/Outflow Crevasses #1 and #2. These additional

detonations allowed the diverted water to return to the Mississippi River at a slower rate (Londoño, et al. 2013).

Officials noticed effects immediately. The floodway received waters flowing at a rate of 15,560 cubic meters per second (the average flow at New Orleans equals almost 17,000 cubic meters per second). An hour after the explosion, river levels dropped 0.15 feet at Cairo. Flood stage decreased upstream, thus decreasing hydraulic pressure downstream (Londoño, et al. 2013).

Although engineers executed the operation according to plan, the events upset homeowners in the floodway. The events sacrificed their farmland and homes to save a larger number of homes. Prior to approval of the detonation, “the state of Illinois and the town of Cairo argue[d] the well-being of Cairo's 2,800 residents outweigh[ed] farmland that would be swallowed up by the rush” (Fox News 2011). Maj. Gen. Mike Walsh of the Army Corps of Engineers further argued, “Every decision we made was calculated into public safety and protecting lives” (Bury et al. 2011). The main argument supporting the operation relied on the reduction of overall flood damages.

E. The Controversy

Fig. 3. Birds Point-New Madrid Floodway Layout (Mississippi River Commission a)



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Fig. 4. Project Design Flood vs. 100 year flood at Cairo, Illinois (Mississippi River Commission a).

An issue engineers must to face is the level of safety design features of structures and infrastructure. For example, no need exists to build an earthquake-proof building in a location not susceptible to earthquakes. With unlimited funds and resources, engineers could easily dismiss this question. However, to cut down on costs, safe and reasonable

construction projects remain necessary. Similarly, with unlimited funds and resources, altering the Mississippi River could occur to flood only certain, uninhabited regions. To do so would result in compensating farmers for their land and lost crops, and redirecting tributaries to flood the designated marshlands as opposed to homes. Add the restriction of funds, and the reality develops with some sections unsatisfied with the decisions. Engineers have the duty to execute an ethical plan.

The destruction of the levees generated controversy. In the levee blast in May 2011, one farmer admitted, “It's a sickening feeling; they're talking about not getting the water off until late July or early August. That knocks out a whole season” (Bury et al. 2011). Although the costs of flood damages to farmland is minimal compared with damage costs in residential areas, many farmers feel they have not received due compensation.

In the initiation of the floodway plan, compensation became necessary for the landowners in the floodway. Administrators postponed the construction of the fuse plugs until the allocation of over half of the flood rights (Mississippi River Commission a). In 1932, administrators offered almost half a million of dollars to landowners for flowage easements. The Department of Justice withdrew their offer after landowners accepted, claiming officials had bid too high. This mistake resulted in uncooperative farmers. Upset with the decision and the project, a resident of the area, A.J. Matthews, filed a lawsuit for compensation of $1.9 million in damages in the event of the use of the floodway. The Mississippi River Commission summarized this court case (b): The court, though, ruled that construction of the floodway at the time the suit was filed did not constitute a taking of the land. Furthermore, the court determined that the land in question would already be inundated from backwater flooding through the 1,500-foot gap by the time stages on the Mississippi River would necessitate the operation of the floodway. In simpler terms, the court essentially found that water on top of water did not represent a taking of the land.

The Mississippi River Commission and the U.S. Army Corps of Engineers intended just compensation for landowners when the floodplain plans commenced. As the U.S. Army Corps of Engineers did not control the funds, the engineers cannot receive blame for unethical compensation (Mississippi River Commission a).

III. CASE STUDIES The following two case studies provide examples of

intentional levee breaches in the United States. Section A describes a flood occurring in 1927 in New Orleans and the controversial food preventative measures taken. Section B involves the return of wetlands around the Cosumnes River of California and describes beneficial reasons to remove levees.

A. Case Study - 1927 The great flood of 1927 occurred in the spring of 1927.

Heavy rain had started in August 1926 and continued for almost a year. Cairo, Illinois, was already at flood stage on January 1, 1927. New Orleans accumulated 15 inches of rain in less than a day on April 15, 1927. After levees in Mounds, Mississippi, Dorena, Missouri, McCrea, Louisiana, to name a few, breached throughout the month of April, New Orleans feared a flood. On April 29, engineers detonated the levee at Caernarvon, Louisiana, downstream of New Orleans. The crew worked on this specific levee to drain floodwaters from New Orleans. The goal planned to relieve the pressure of levees further upstream (Risk Management Solutions 2007).

The controversy here lies in the areas chosen to flood. Floodwaters rushed into the parishes of St. Bernard and Plaquemines, the poorer communities south of New Orleans. Although the mayor of New Orleans and the governor of Louisiana promised compensation, few residents received any benefits. Regardless, this intentional breach of the levees may have constituted an unnecessary intervention. Natural breaches upstream of New Orleans resulted in excess floodwaters passing through the Atchafalaya Channel, which ends at the sea (Risk Management Solutions 2007). Little evidence supports the argument that poorer, more rural areas suffered intentional flooding to save the properties of the rich.

The officials of New Orleans and Louisiana believed this process offered the best course of action for its residents. The strategy followed no preconceived plan. City engineers proposed a plan of this magnitude as a last-minute effort. As a



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“better of two evils” execution, seaplanes did ensure that the full evacuation of residents did occur before the activation of explosives (“City to Feel Relief,” 1927).

This event, like the levee breaches in the Birds Point-New Madrid Floodway, occurred solely to prevent further flooding in New Orleans. Other reasons exist, however, to remove or destroy a levee.

B. Case Study – Cosumnes River The Cosumnes River, located in California, is the only river

flowing from the Sierra Nevada that remains an unregulated stretch apart from levees (Swenson et al. 2011). Thus, the alteration of the hydrology of this river remains less than that for rivers containing large dams. Levee building occurred to control the river and protect farmland. As a result, natural floodplains became redundant. Less than five percent of these areas contained forest in the late 1980s. Native fish species, such as Sacramento splittail and Chinook salmon adapted to and thrived in the seasonal wetlands during flood season. Invasive species do not prosper as well as native species in these habitats (Swenson et al. 2011). Constricting the river also contributed to lowering ground water levels. During the dry season, more demands for water from the river existed above and beyond the supply that the Cosumnes River could support. Chinook salmon could not swim upstream to spawn and towns pumped more water from the ground. Ground water level measurements declined by as much as 60 feet (Swenson et al. 2011).

The Cosumnes River Preserve is responsible for preserving floodplains to restore the natural riparian forests and native species. In the early 1990s, restoration developed in the form of hand planting cottonwood and willow trees and building wetlands. This tedious process yielded little results as trees either slowly or simply failed to grow. In 1985, a levee naturally breached, flooding 15 acres of farmland. Sand and sediment deposits ruined the field. By the end of 1985, an “accidental forest” emerged. In 2001, the cottonwood trees towered over 40 feet and the accidental forest provided a home for many species, including songbirds, deer, and beaver (Swenson et al. 2011). This forest, which grew without human assistance, grew faster and more successfully than the hand planting techniques previously used.

In 1995, engineers intentionally breached levees along the river. This effort involved a two-part study to determine if natural flooding of the Cosumnes River promoted the growth of the natural, historical habitat and if flooding from the river relieved river stages both upstream and downstream. Funding from the U.S. Environmental Protection Agency facilitated the creation of a gap in a section of levee in October 1995. By December, the river began to flood. The hypothesis proved correct. Excess precipitation had a location to occupy rather than being constricted and forced downstream. Pressure releases occurred both upstream and downstream. In addition, woodcuttings flowed downstream and settled in the sand deposits. Five years later, these cuttings grew into a forest with an average height of 11 feet (Swenson et al. 2011). A study determined that these wetland trees grew better from natural cuttings than seeds (Swenson et al. 2011).

The Cosumnes River saw more flooding in the beginning of 1997. Many sections of the levee naturally breached. Instead

of repairing the levees, the Cosumnes River Preserve approached the U.S. Army Corps of Engineers to assist funding of levee destruction. Controlling where levee removal would occur, floodplains could develop, similar to what resulted in the “accidental forest” and the 1995 project. To protect the farmland adjacent to the uninhabited floodplains, engineers constructed setback levees (Swenson et al. 2011). Project plans detailed almost six miles of levees rendered permanently inoperable, adding 100 acres of floodplain. Although the project cost $1.55 million, future costs for flood management, such as emergency repairs and maintenance, have decreased (Swenson et al. 2011). The Cosumnes River also has a thriving forested floodway full of wildlife and native fish. This environment has helped improve the Chinook salmon and Sacramento splittail populations. The groundwater table has time to recharge when water inhabits in the floodway. This improves the flow in the river, which reduces the strain on aquifer. In addition, a higher flow during the drier seasons aids salmon to spawn upstream.

IV. CONCLUSION Levees are structures intended to contain waterways.

Instead of relying more on levees, the U.S. Army Corps of Engineers began to remove levees and destroy others during flood events. Nature has always taken care of itself. Historically, when rivers flood, they overflow into the neighboring lands. Disrupting this process with levees often makes rivers even harder to control.

As the Mississippi River became harder to control, more reliable flood preventative measures became necessary. Designated floodways allow the river to flood surrounding areas as necessary, but at convenient locations. The ethics controversy stems from this main issue. During the 1927 levee detonation near New Orleans, a matter of ethics existed within the local government. Engineers unnecessarily directed floodwaters to the poorer districts. Compensation promises occurred, but remained unfulfilled in most cases. Government actions, not engineers, proved responsible for these two unethical actions. Government officials gave the orders and made the promises to cover the damages.

On the other hand, the argument exists that engineers are responsible for allegedly unethical flooding in the Birds Point-New Madrid Floodway. The U.S. Army Corps of Engineers provided the floodway project as an alternate to levees. Again here, engineer responsibility did not extend to the provision of funds for damages or easements. The Department of Justice should admit liability for retracting their previous offer for easements. Today, all of the land in the floodway has an official designation for such uses. The Army Corps of Engineers detonates the fuse plug according to approved plans. The two hundred people who inhabit the farmland would suffer damages, but not without prior warning.

As shown with the Cosumnes River project, allowing rivers to flood plains provides a location for the excess water to distribute. Intentionally abandoning certain levees around the Cosumnes River recharged the ground water and improved the year-round flow. Salmon now have a greater chance at swimming upstream to spawn and the aquifer has time to recharge and become more stable. In the case of the



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Cosumnes River, one flood in a farm field resulted in a forest; the ecosystem revived itself by flooding as it did in the past. Riparian forests grow in acres in this watershed, promoting diverse habitats.

No solutions exist for replacing levees, other than installing a dam. Dams are very expensive and alter the ecosystem more than levees do. Aiding the environment to return to its prior condition around human settlements offers the most beneficial solution. Outside circumstances around the transition from levees to floodplains suggest interpretations of unethical behavior, but not on the engineering aspect. One feasible future option, reliant on adequate land allocations, would designate and use more floodplains. This process would benefit the environment while protecting human infrastructure.

ACKNOWLEDGMENT The author thanks Dr. Tanya Kunberger for her assistance

and guidance in producing this report.

REFERENCES Bury, C. and Friedman, E. (2011). “Army Corps Breaks Open Missouri Levee

to Save Town” <abcnews.go.com> (Aug. 28, 2013). “City to Feel Relief from Levee Breach in 48 Hours.” (1927). Times-

Picayune, XCI (96), 1-3. Fox News (2011). “Judge Gives Go-Ahead to Break Mississippi River

Levee.” <www.foxnews.com> (Aug. 28, 2013). Londoño, A.C. and Hart, M.L. (2013). “Landscape response to the intentional

use of the Birds Point New Madrid Floodway on May 3, 2011.” Journal of Hydrology, 489, 135-147.

Henze, Laura (2011). “Before and after: A controversial flood plan put to use.” Need to Know on PBS. <www.pbs.org> (Dec. 9, 2013).

PBS (2010). “The Mississippi River commission and the Army Corps of Engineers.” <www.pbs.org> (Aug. 28, 2013).

Pinter, N., Ickes, B.S., Wlosinski, J. H., and van der Ploge, R.R. (2006). “Trends in flood stages: Contrasting results from the Mississippi and Rhine River systems.” Journal of Hydrology, 331(3-4), 554-566.

Risk Management Solutions (2007). “The 1927 Great Mississippi Flood: 80-Year Retrospective.” RMS Special Report. <https://support.rms.com/publications/1927_MississippiFlood.pdf> (Oct. 12, 2013).

Swenson, R.O., Whitener, K., and Eaton, M (2001). “Restoring floods to floodplains: Riparian and floodplain restoration at the Cosumnes River Preserve.” Riparian Habitat and Floodplain Conference Proceedings. <http://www.sjrdotmdl.org/concept_model/phys-chem_model/documents/300001823.pdf> (Dec. 7 2013).

Trotter, P.S., Johnson, G.A., Ricks, R., and Smith, D.R. (1998). “Floods on the Lower Mississippi: An Historical Economic Overview.” <www.srh.noaa.gov> (Dec. 8 2013).

Mississippi River Commission. “MR&T Birds Point-New Madrid Information Paper.” The Mississippi River & Tributaries Project. <www.mvd.usace.army.mil> (Oct. 10, 2013). (a)

Mississippi River Commission. “MR&T Controlling the Project Flood Information Paper.” The Mississippi River & Tributaries Project. <www.mvd.usace.army.mil> (Oct. 10, 2013). (b)

Mississippi River Commission. “Floodways.” The Mississippi River & Tributaries Project. <www.mvd.usace.army.mil> (Dec. 9, 2013). (c)

moloney ethics artificial levee breaches - fort myers, florida · since the late 1700s, ... the...

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