Ecosystem
Alteration
Below
is a timeline of major events and legislative action that have
contributed to the large-scale alteration of the Coastal Louisiana
ecosystem:
General
Survey Act of 1824
Congress passed the General Survey Act authorizing the President
to employ civil engineers and officers of the Army Corps of
Engineers to make surveys, plans, and estimates for "routes
of such roads and canals as he may deem of national importance
in a commercial or military point of view, or necessary for
the transportation of public mail."
Roads
and Canals Act of 1824
Within one month of passage of the General Survey Act, Congress
passed the Roads and Canals Act appropriating $75,000 to the
Army Corps of Engineers to improve navigation on the Ohio and
Mississippi Rivers by removing sandbars, snags, and other obstacles.
Rivers
and Harbors Act of 1826
Congress passed the Rivers and Harbors Act authorizing the President
to have river surveys undertaken to clean out and deepen selected
waterways and to make various other river and harbor improvements.
In consolidating both planning and construction, the Act became
the first true river and harbor law.
Mississippi
River flood, 1828
Generally believed to be the greatest flood of the nineteenth
century, the Mississippi River flood of 1828 caused widespread
damage to the region.
Swamp
Land Acts of 1849, 1850 and 1860
The Swamp Land Act of 1849 granted to Louisiana all swamp and
overflow lands then unfit for cultivation, the object being
to help in controlling floods in the Mississippi River Valley.
Collectively, the Swamp Land Acts of 1849, 1850, and 1860 granted
more than 9 million acres of swamp to Louisiana alone, and nearly
65 million acres of wetlands in 15 states from the federal government
to state governments to expedite drainage.
Charles
Ellet Report, 1852
Charles Ellet, a civil engineer working for the Army Corps of
Engineers, completed a topographical and hydrographical survey
of the delta of the Mississippi River. His report to Congress
advocated greater federal responsibility for the control of
floods in the lower Mississippi River and favored a comprehensive
plan for controlling floods -- a plan which included, in addition
to levees, the construction of reservoirs and diversion channels.
Publication
of Mississippi River Report, 1861
Engineers Humphreys and Abbot released their report on the physics
and hydraulics of the Mississippi River -- completed after more
than ten years of exhaustive research. The report represented
the most thorough analyses of the Mississippi River to date,
both in terms of data gathered and conclusions rendered, and
won the respect of engineers around the world. It also heavily
influenced the development of flood control policy on the river
system well into the next century.
Flood
and Warren Commission Report, 1874
A great flood in 1874 exploited the still weakened levee system
of the Mississippi River and wrecked havoc on the lower valley.
The resulting suffering and devastation forced the federal government
to redirect its attention to the flood problems of the delta.
That year, the U.S. Congress approved an act creating a commission
of engineers "to investigate and report a permanent plan
for the reclamation of the alluvial basin of the Mississippi
River subject to inundation." To that end, President Grant
appointed General G. K. Warren as commission chairman and appropriates
$25,000 for the study. After considerable analysis of the flood
problem in the delta, the Warren Commission criticized the efforts
and methods of local flood control and emphasizes the need for
greater federal commitment to control the Mississippi River.
The report's solid recommendation for greater federal commitment
stimulated the growth of favorable public sentiment and encouraged
flood control advocates in Congress.
Construction
of jetties at mouth of the Mississippi, 1875
The use of steam greatly increased the size of ocean-going vessels,
but the larger ships found it more and more difficult to navigate
the bars that choke the Mississippi River's several outlets
to the sea. Attempts to maintain an open channel through the
use of dredges failed repeatedly. The Army Corps of Engineers
advocated for the construction of a parallel canal. Instead,
Congress authorized civilian engineer, James B. Eads, to build
jetties at the mouth of the Mississippi River.
Creation
of House Standing Committee on Mississippi Levees, 1875
Led by Louisiana Congressman Randall Lee Gibson, flood control
advocates convinced House Speaker Michael C. Kerr of Indiana
to authorize the creation of a House Standing Committee on Mississippi
Levees. Beginning with its inception in December 1875, the Committee
became the voice for flood control interests in Congress and
remained so for more than thirty-five years.
Mississippi
River Commission Act of 1879
Representing the first federal attempt to develop a coordinated
plan for the development of the Mississippi River, Congress
established the Mississippi River Commission; a seven-member
advisory board made up of three Army Corps of Engineers representatives,
one Coast and Geodetic Survey representative, and three civilians
(at least two of whom must be engineers). Congress tasked the
Commission with developing and overseeing the implementation
of plans to "improve and give safety and ease to navigation"
and to "prevent destructive floods" on the Mississippi
River. The Army Corps of Engineers was charged with conducting
the work, and also with supplying necessary plants and equipment.
Completion
of a system of jetties at the mouth of the Mississippi River,
1879
Civilian engineer James B. Eads completed building a system
of jetties at the mouth of the Mississippi River. The jetties
shaped the development of river-management policy for the lower
Mississippi River and revealed that under the right circumstances
jetties could direct the river to scour out and deepen its own
channel. Before long, prominent civil and military engineers
became convinced that the Mississippi's own energies could be
used to deepen the channel and improve navigation along the
whole length of the river. Flood control advocates in Congress
seized upon the idea that a properly-constructed levee system
could promote navigational improvements, and began looking for
ways to implement Eads' ideas.
Flood
Control, 1880s
The Army Corps of Engineers began constructing flood control
structures throughout the Upper Mississippi River System. By
constraining and redirecting the river channel and cutting it
off from its floodplain, the flood control measures greatly
altered the hydrology of the entire Mississippi River system
as well as the terrestrial and aquatic ecosystems it supported.
Canal
dredging, 1880s
Early settlers, and the people and companies who follow them,
dredged canals through Louisiana's wetlands for drainage and
cut channels for commerce. These measures made more of the Deltaic
Plain habitable, but eventually tilted the balance toward wetland
destruction.
Congressional
Appropriation Bill, 1881
The Congressional Appropriation Bill of 1881 included a provider
restricting the Mississippi River Commission's authority to
construct levees for the purpose of flood control.
Congressional
Appropriation Bill, 1882
The Congressional Appropriation Bill of 1882 authorized the
Army Corps of Engineers to undertake levee construction for
the purpose of improving navigation, but not for flood control.
Rivers
and Harbors Appropriations Act, 1882
The 1882 River and Harbors Appropriations Act combined appropriations
for development of the nation's waterways with a reaffirmation
of the policy of freedom from tolls and other user charges.
The Act signaled Congress' intent to improve waterways to benefit
the nation by promoting competition amongst transportation modes.
Dam construction,
1884 - 1912
The Army Corps of Engineers began construction of six dams on
the Upper Mississippi River in Minnesota to stabilize water
levels downstream. Construction was complete by 1912.
Mississippi
River flood, 1890
The Mississippi River flood of 1890 proved that levees on the
river system were inadequate and focused Congressional attention
on river problems. The flood provided evidence that the Mississippi
River Commission's efforts, together with state and local levee
organizations, to contain the river's main channel and close
off its natural outlets contributed to higher flood levels.
River
and Harbor Act of 1890
In reaction to the severe Mississippi River flood of 1890, the
River and Harbor Act of 1890 appropriated $3.5 million to the
Mississippi River Commission. For the first time bill language
did not include the standard provider against levee construction
for the purpose of controlling floods. The landmark piece of
legislation contributed to the rapid expansion of levee construction
under the Mississippi River Commission.
Coastal
erosion, 1890s - 1960s
Massive coastal erosion in Louisiana began in 1890s and peaked
during the 1950s and 1960s. The erosion resulted in loss and
deterioration of wetlands, barrier islands, and ridges. During
a period of little more than 100 years, more than one million
acres, or about 20 percent of the coastal lowlands (mostly wetlands)
was lost.
Mississippi
River Commission, 1896
The Mississippi River Commission admitted that its attempts
to improve navigability of the Mississippi River through bank
revetment and contraction works, had generally failed. By temporarily
abandoning these expensive river improvement efforts, the Commission
was able to concentrate ever greater percentages of its resources
on the construction of levees.
Mississippi
River flood, 1897
The devastation caused by the Mississippi River flood of 1897
forced Congress to reassess the value and direction of its flood
control program for the Lower Mississippi River.
Nelson
Report, 1898
A Congressionally-sponsored investigation into alternative flood
control methods yielded no change in Mississippi River flood
control policy. Instead, the Nelson report advocated for the
continuation of a levees-only policy for the Lower Mississippi
River.
Mississippi
River flood, 1898
For the first time since the commencement of a continuous levee
line along the Lower Mississippi River, the Mississippi River
flood of 1898, reaching a height of fifty feet at Cairo, Illinois,
was safely discharged to the Gulf of Mexico without a single
break in the levees.
River
and Harbor Act of 1894
The River and Harbor Act of 1894 authorized the Secretary of
the Army to prescribe rules and regulations for the use, administration,
and navigation of any or all canals and similar works of navigation
owned, operated, or maintained by the U.S.
River
and Harbor Act of 1899
The River and Harbor Act of 1899 authorized approval for the
construction of bridges, dams, and dikes across any navigable
water of the U.S. The Act also required that structures built
under state authority required approval from the Chief of Engineers
and the Secretary of the Army. In addition, the Act prohibited
the placement of obstructions to navigation outside established
federal lines, and excavating from or depositing material in
such waters, unless a permit for the works had been authorized
by the Secretary of the Army.
Levee
building, wetlands draining, canal digging, 1900s
Louisiana residents continued to fight the constraints imposed
by the area's coastal ecosystem, building levees to guard against
flooding, draining wetlands to expand usable land, digging canals
to expand drainage and navigation networks, and providing access
for transport of timber, oil, and gas.
Mississippi
River flood, 1903
The Mississippi River flood of 1903 once again breached the
levees. According to the Mississippi River Commission, all crevasses
in the line resulted from the "unfinished nature of the
levees as regards both grade and section." The push for
higher levees continued.
Interstate
Inland Water League, 1905
With the goal of forming a continuous system of 18,000 miles
of navigable waters extending from the Great Lakes through the
Mississippi Valley and along the Louisiana and Texas coastlines,
a convention in Texas gave birth to the Interstate Inland Waterway
League. The league eventually became known as the Gulf Intracoastal
Canal Association.
River
and Harbor Act of 1906
The River and Harbor Act of 1906 expanded the jurisdiction of
the Mississippi River Commission by authorizing the construction
of levees between the Head of Passes and Cape Girardeau, Missouri,
and it extended the Commission's responsibilities for levees
above Cairo, Illinois, to the head of the St. Francis Basin.
Rivers
and Harbors Act of 1907
Providing for the first Louisiana segment of the Gulf Intracoastal
Waterway, Congress appropriated $89,292 in the Rivers and Harbors
Act to connect the Bayou Teche at Franklin with the Mermentau
River.
Mississippi
floods of 1912 and 1913
In 1912 and 1913, the Mississippi Valley experienced successive
record-breaking floods which precipitated a crisis in the Army
Corps' reclamation program. The tremendous expense incurred
as a result of the regular inundation of the Valley, combined
with the cost of building, maintaining, and repairing the levee
system, became counter-prohibitive. Out of self-preservation,
landowners in the valley launched a massive propaganda campaign
directed at obtaining greater federal commitment.
Townsend
Report, 1913
Following the Mississippi River flood of 1913, President Woodrow
Wilson directed the Mississippi River Commission to submit a
report on flood control. The report, authored by Mississippi
River Commission President, Colonel Curtis Townsend, considered
six methods of flood control: reforestation, reservoirs, cut-offs,
outlets, floodways, and levees. As with all previous reports,
the Commission condemned the various alternatives to levees
and advocated for a continuation of policy.
River
and Harbor Act of 1913
The River and Harbor Act of 1913 expanded the Mississippi River
Commission's jurisdiction up to Rock Island, Illinois, with
certain restrictions.
Ransdell-Humphreys
Act of 1917
The Ransdell-Humphreys Act of 1917, the first federal flood
control act, committed the federal government, for the first
time, to flood control for the Mississippi Valley. The Act also
extended the Mississippi River Commission's jurisdiction to
include water-courses connected with the Mississippi River to
the extent necessary to exclude flood waters from the upper
limits of any delta basins.
Flood
Control Act of 1923
The Flood Control Act of 1923 authorized $60 million for levee
construction over a ten-year period for the purpose of completing
the levee system along the Lower Mississippi River.
Inland
Waterways Corporation, 1924
Congress created the Inland Waterways Corporation to promote,
encourage, and develop water transportation, service, and facilities
in connection with the commerce of the U.S., and to foster and
preserve in full vigor both rail and water transportation. To
fulfill the water transportation provision, the Corporation
operated barges under the name Federal Barge Lines on the Mississippi-Missouri
and Warrior Rivers.
Levee
system complete, 1926
The Mississippi River Commission concluded in its annual report
that the river's levee system "is now in a condition to
prevent the destructive effects of floods."
River
and Harbor Act of 1927
The River and Harbor Act of 1927 authorized the Army Corps of
Engineers to undertake comprehensive surveys and formulate general
plans for the most effective improvement of navigable streams
and their tributaries, and the prosecution of these improvements
in combination with the development of potential water power,
the control of floods, and the need for irrigation. The surveys,
called "308 reports," established the first comprehensive
river-basin development plans for the nation and provide authority
to the Army Corps of Engineers for surveying and planning navigation
systems for inland waters.
Great
Mississippi Flood of 1927
The Great Mississippi Flood of 1927 devastated the Mississippi
River region. Herbert Hoover, then Secretary of Commerce, called
the flood "the greatest peace-time calamity in the history
of the country." The Mississippi River Commission's prized
levee system - the culmination of almost fifty years of work
- proved unequal to the task. The high water caused 17 breaks
in the main levee line and 209 crevasses on the tributaries
of the Mississippi. The flood waters overflowed an estimated
11,000,000 acres from Cairo, Illinois, to Natchez, Mississippi,
on the west bank and from the mouth of the Arkansas River to
Vicksburg, Mississippi, on the east bank. In terms of gauge
readings, volume of discharge, and destruction, the flood of
1927 was unprecedented. 246 people died as a result of the flood;
700,000 people were forced from their homes; 1,500,000 farm
animals were destroyed; and the Lower Mississippi Valley, including
parts of seven states, remained flooded for five months. Total
property loss and damage was estimated at between $200 and $400
million, exceeding the aggregate losses of all previous Mississippi
floods.
Flood
Control Act of 1928
Responding to the 1927 flood disaster, Congress overhauled the
flood control plan for the Lower Mississippi River. After much
debate, the Flood Control Act of 1928 was approved, authorizing
the Mississippi River Commission to implement Chief of Engineers,
Major General Edgar Jadwin's plan for controlling floods on
the Lower Mississippi River, including the abandonment of a
levees-only policy and the adoption of a comprehensive flood
control plan using floodways and spillways, including through
the Atchafalaya Basin, as well as levees. The plan provided
for enlarging and strengthening the levees from Cape Girardeau,
Missouri, to the Gulf of Mexico, with the objective of safely
discharging up to 1,500,000 cubic feet/second of water within
the main channel.
Introduction
of Nutria, 1930s
Nutria were accidentally released to coastal Louisiana. The
small, semi-aquatic rodents multiplied rapidly, grazing heavily
on marsh plants. The grazing imposed additional stress on marsh
plants, frequently resulting in mortality, as well as physically
disrupting the substrate and accelerating marsh loss.
Mississippi
River Commission cut-off policy, 1932
Studies carried out by the newly created Waterways Experiment
Station convinced the Mississippi River Commission to initiate
a series of cutoffs in the middle reaches of the Mississippi
River. Within nine years, 16 such cutoffs shortened the distance
from Memphis, Tennessee, to Vicksburg, Mississippi, by 170 miles
and reduced flood heights along the main channel considerably.
The successful development of these cutoffs marked a new phase
in the evolution of flood-control engineering.
Congressional
Resolution, 1932
Congress passed a resolution requesting an examination and review
of the status and condition of works, then in progress, as authorized
by the Flood Control Act of 1928, with a view to determining
if changes or modifications should be made in relation to the
project and its final execution.
Overton-Dear
Act of 1934
The Overton-Dear Act of 1934 resolved the bitter controversy
which had arisen from conflicting interpretations of the Flood
Control Act of 1928. In the Act, the government abandoned its
efforts to compel owners of property along the tributaries of
the Lower Mississippi River to donate levee rights-of-way at
no cost to the Government.
Review
of flood works report, 1935
In accordance with the Congressional resolution of 1932, the
Army Corps of Engineers submitted a report to Congress reviewing
the status and condition of works then in progress as authorized
by the Flood Control Act of 1928. The report concluded that
the New Madrid Floodway levees at Cairo, Illinois, were nearly
complete; the Bonnet Carre Spillway at New Orleans, Louisiana,
was essentially complete; and neither of the larger floodways
(Morganza and Boeuf) was yet under construction.
Ohio-Mississippi
River flood, 1937
The Ohio-Mississippi River flood of 1937 forced operation of
the New Madrid floodway at Cairo, Illinois, and the Bonnet Carre
Spillway near New Orleans, Louisiana. The cutoffs initiated
in 1932 along the Mississippi below the mouth of the Arkansas
River accelerated discharges and lowered flood heights by as
much as five feet.
The Gulf
Intracoastal Waterway and the Mississippi River Gulf Outlet,
1949
An east-west connector of international ports, the Gulf Intracoastal
Waterway, was completed by the Army Corps of Engineers to carry
barges of crude oil, petroleum, bulk cargoes, and miscellaneous
items along a 12-foot deep channel protected from the storms,
waves, and winds of the Gulf of Mexico.
Outbreak
of World War II, 1940
The outbreak of World War II promoted the recovery of the national
economy, and substantially increased Mississippi River commerce.
Unimpeded navigation also became essential for military operations;
almost 4,000 Army and Navy craft moved from inland shipyards
down the Mississippi to the Gulf of Mexico.
Flood
Control Act of 1941
At the request of the Arkansas delegation, Congress removed
plans for construction of the Eudora Floodway from the Mississippi
River Commission's series of projects in favor of higher levees.
The Flood Control Act of 1941 also authorized the Yazoo Backwater
Project to protect the Delta area of Mississippi from the increased
stages. The project included a combination of levees, drainage
structures, and pumps.
Congressional
resolution, 1943
The House Flood Control Committee and the Senate Committee on
Commerce passed a resolution calling on the Army Corps' Chief
of Engineers and the Mississippi River Commission to submit
a report on the feasibility of amending the navigation provisions
of the Flood Control Act of 1928, with specific reference to
increasing channel depths from 9 to 12-feet from Cairo, Illinois,
to Baton Rouge, Louisiana.
Mississippi
River flood, 1943
During the flood of 1943, the Mississippi River reached its
second highest level in recorded history. Cape Girardeau, Illinois,
recorded a level of 42.3 feet.
Mississippi
River Commission report, 1944
At the request of Congress, the Mississippi River Commission
released its report on the feasibility of increasing channel
depths below Cairo, Illinois. After thorough analysis, the Commission
concluded that stabilization efforts already underway, together
with additional dredging, might be enough to provide a 12-foot
deep channel below Cairo, Illinois.
Flood
Control Act of 1944
Based on the Mississippi River Commission report, the Flood
Control Act of 1944 authorized approximately 150 additional
projects throughout the nation at a cost of $750 million, including
approval for a 12-foot channel in the Mississippi River between
Cairo, Illinois, and Baton Rouge, Louisiana, as well as a $200
million stabilization program. The Act also required all subsequent
navigation and flood control projects be subject to the approval
of the affected states. In addition, the Act articulated a new
policy for the development of recreation facilities at reservoirs,
stipulating that public reservoirs be open for public use without
charge for boating, swimming, bathing, fishing, and other recreational
purposes. This new responsibility represented an important step
toward multi-purpose development of the nation's water resources.
Atchafalaya
Basin study, 1950
A major Army Corps of Engineer study determined that, without
interference of some kind, Louisiana's Atchafalaya Basin would
capture the Mississippi River by 1975. To prevent this, the
Army Corps urged Congress to authorize the construction of a
controlled connection along the Old River in order to regulate
the volume of water allowed into the Atchafalaya Basin.
Levee
system construction, 1950s-1970s
Construction of an extensive levee system along the Mississippi
River, with the goal of maintaining navigation and reducing
the flooding of adjacent homes and businesses, began in the
1950s. The system prevented Louisiana's coastal wetlands from
receiving their regular nourishment of riverine water, nutrients,
and sediment -- a diet crucial to wetland survival. These regional
impacts were exacerbated by other hydrologic alterations that
modified the movement of fresh water suspended sediment, and
saltwater through the system. Canals dredged for navigation,
or in support of mineral extraction, allowed saltwater to penetrate
into previously fresh marshes. In time, efforts to open and
maintain navigation channels to the Gulf disrupted the Chenier
Plain's stable wetland system and dredged ship channels allowed
salt water into previously isolated freshwater marshes, particularly
during hurricanes.
Mississippi
River Commission report, 1954
The Mississippi River Commission reported that its flood control
efforts had progressed to the point that most of the inhabitants
of the Mississippi Valley were now safe from a 1927-caliber
flood. Seventy-five percent of the bank revetment was completed,
and only 250 miles of main-line levees remained unfinished.
Mississippi
River Gulf Outlet, 1960s - 1990s
Construction of the Mississippi River Gulf Outlet in the 1940s
led to high marsh loss in the areas surrounding the outlet and
in areas more removed such as the Pontchartrain/Maurepas Land
Bridge. In 1963, the Army Corps of Engineers opened up a new
channel through the wetlands of St. Bernard Parish because the
vegetation offered natural protection from wind, waves, and
storms. During the next 30 years, the outlet became a major
source of land loss and saltwater intrusion. As a result of
increasing erosion, the main channel also widened from 500 to
2,000 feet.
Hurricanes,
1960s - 2002
In 1965, the eye of Hurricane Betsy passed 50 miles west of
New Orleans. Tidal water surged in Plaquemines, St. Bernard,
and Orleans Parishes, causing $2 billion in damages and 81 deaths.
Following Hurricane Betsy, work began on a billion-dollar hurricane
protection system around the south shore of Lake Pontchartrain.
Completed in 2002, the system in theory would be be able to
shelter the city from a Category 3 hurricane storm surge. But
in reality, whether or not a surge overtops the levees depended
on the storms.
Flood
Control Act of 1960
To discourage further encroachment on the flood plains, Congress
in the Flood Control Act of 1960 authorized the Army Corps of
Engineers to compile and disseminate information on floods and
flood damage, to identify areas subject to overflow, and to
present general criteria for guidance in the use of flood plain
areas.
River
and Harbor and Flood Control Act of 1965
The River and Harbor and Flood Control Act of 1965 authorized
150 Army Corps projects or project modifications at an estimated
cost of $2 billion, including a long-range master plan for stabilizing
the Mississippi River between Cairo, Illinois, and Baton Rouge,
Louisiana, to facilitate the establishment of a 12-foot channel
depth.
Hypoxia
in the Gulf of Mexico, 1970s - 2000s
Dramatic changes in Mississippi River nutrient concentrations
and loadings to the adjacent continental shelf over the course
of the 20th century resulted in the occurrence of zones of severe
oxygen depletion, known as Hypoxia, in the Gulf of Mexico. Studies
revealed that nitrogen was the principal nutrient responsible
for the zones. The majority of Mississippi River nitrogen originated
from agricultural practice, while smaller fractions arise from
human sewage, nonagricultural fertilizer use, and precipitation.
Mississippi
River flood, 1973
The Mississippi River flood of 1973 caused widespread damage,
resulting in 23 deaths, and a record 62 days-out-of-bank. Total
cost of the flood was estimated at $183 million.
Mississippi
Delta Flood Control Projects, 2004
The Army Corps of Engineers moved forward with a controversial
plan for two flood-control projects in the Mississippi Delta
that would drain tens of thousands of acres of flood-prone wetlands
and dredge more than 100 miles of river bottom in an effort
to boost agricultural production, remove contaminated soil,
and protect about 1,500 homes from flooding.
