This is the accessible text file for GAO report number GAO-12-41
entitled 'Mississippi River: Actions Are Needed to Help Resolve
Environmental and Flooding Concerns about the Use of River Training
Structures' which was released on December 9, 2011.
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United States Government Accountability Office:
GAO:
Report to Congressional Requesters:
December 2011:
Mississippi River:
Actions Are Needed to Help Resolve Environmental and Flooding Concerns
about the Use of River Training Structures:
GAO-12-41:
GAO Highlights:
Highlights of GAO-12-41, a report to congressional requesters.
Why GAO Did This Study:
For more than 130 years the U.S. Army Corps of Engineers (Corps) has
used dikes to “train” the Mississippi River channel and maintain
adequate depth for navigation. The Corps relies heavily on these
structures-—including some with more recent designs-—in the Middle
Mississippi, between the confluences of the Missouri and Ohio Rivers.
Over the past few decades, some researchers have raised concerns about
the structures’ cumulative impacts on the environment and the height
of floodwaters. For the Corps’ river training structures in the Middle
Mississippi, GAO was asked to examine (1) key requirements and
directives that govern their use, (2) how the Corps has addressed key
environmental requirements, (3) the extent to which their hydrologic
and environmental impacts are monitored, and (4) concerns that
researchers have raised about hydrologic and environmental impacts and
how the Corps has responded. GAO reviewed relevant laws, regulations,
agency documents, and key studies, and interviewed Corps officials and
other researchers and experts.
What GAO Found:
The Corps’ authority to use river training structures in the
Mississippi River comes from several Rivers and Harbors Acts, which
collectively require the Corps to maintain a 9-foot navigation channel
in the river, and several Water Resources Development Acts, which also
authorize projects in the Corps’ civil works program. In using these
structures, the Corps must comply with federal environmental laws such
as the National Environmental Policy Act (NEPA), the Clean Water Act
(CWA), and the Fish and Wildlife Coordination Act, as well as
applicable state requirements. The Corps also has its own guidance
that district offices are to use when planning, designing, and
building river training structures.
In using river training structures in the Middle Mississippi, the
Corps has addressed some environmental requirements but not all. For
example, the Corps has undertaken consultation with other agencies in
accordance with the Fish and Wildlife Coordination Act. However, the
Corps has not complied with certain requirements of NEPA or CWA. For
example, in constructing new river training structures the Corps has
continued to rely on an environmental impact statement prepared in
1976. Even though significant changes have occurred in the river and
in the Corps’ design of its structures, it has not prepared the
additional analyses required by NEPA to assess whether further
environmental impact analysis is warranted. Similarly, the Corps has
not obtained the appropriate CWA permits or state water quality
certifications for river training structures as required.
The Corps routinely assesses some of the hydrologic impacts of its
Middle Mississippi training structures but not the environmental
impacts. For example, the Corps has performed physical and numerical
modeling to assess the hydraulic impacts of proposed structures prior
to construction, and it has routinely monitored the hydrologic impacts
after construction through data collection and observation of the river’
s surface elevation (known as river stage). The Corps has also
analyzed the relationship between river stage and the volume and speed
of river flow (known as discharge), looking for rising or falling
trends that might indicate whether the structures are having a
cumulative effect during floods. The Corps, however, does not
routinely monitor the environmental impacts of its structures after
construction, although it has conducted studies to monitor impacts on
certain endangered species, such as the pallid sturgeon, and on fish
and wildlife habitats.
Researchers have highlighted two key areas of concern with river
training structures—degradation of river habitat and increased
flooding. Although the Corps has attempted to address the habitat
concerns, the agency and some researchers disagree over flooding
concerns. In response to the habitat concerns, the Corps has modified
some river training structures to increase flows between them, and has
begun installing newer types of structures in select locations to
promote aquatic habitat. Regarding flooding, the Corps disagrees with
the concern that its structures have led to an increase in river stage
during high flow events, and has undertaken various studies that
support its position. Nevertheless, significant professional
disagreement remains over this issue, which many experts believe could
be resolved through additional physical and/or numerical modeling.
What GAO Recommends:
GAO recommends that the Department of Defense direct the Corps to
prepare an environmental assessment for river training structures in
the Middle Mississippi, obtain required water quality permits for new
structures, and conduct physical and/or numerical modeling to assess
the cumulative impact of structures on flood heights. The department
generally agreed with these recommendations.
View [hyperlink, http://www.gao.gov/products/GAO-12-41]. For more
information, contact Anu K. Mittal at (202) 512-3841 or
mittala@gao.gov.
[End of section]
Contents:
Letter:
Background:
River Training Structures Must Adhere to Key Federal and State
Requirements and Corps Guidance:
The Corps Has Addressed Some but Not All of the Environmental
Requirements for River Training Structures:
The Corps Has Routinely Monitored the Hydrologic Impacts of River
Training Structures after Construction, but Has Not Routinely
Monitored Their Environmental Impacts:
The Corps Has Modified Structures over Environmental Concerns but
Disagrees That They Exacerbate Floods:
Conclusions:
Recommendations for Executive Action:
Agency Comments and Our Evaluation:
Appendix I: Objectives, Scope, and Methodology:
Appendix II: Comments from the Department of Defense:
Appendix III: GAO Contact and Staff Acknowledgments:
Figures:
Figure 1: Management Area of the Six Districts within the Corps'
Mississippi Valley Division:
Figure 2: Wing Dikes in the Middle Mississippi:
Figure 3: Simplified Illustration of a River Cross-Section before and
after Installing a Wing Dike:
Figure 4: Illustration of Submerged Bendway Weirs on the Outside of a
River Bend:
Figure 5: Chevrons in the St. Louis Harbor:
Figure 6: Photograph of a Small-Scale Physical Model:
Figure 7: 1993 Rating Curve for the St. Louis Gauge:
Figure 8: Specific Gauge Analysis for the St. Louis Gauge:
Figure 9: Aerial and Close-up Views of Notched Wing Dikes in the
Mississippi River:
Figure 10: Close-up View of a Chevron in the St. Louis Harbor:
Abbreviations:
Corps: U.S. Army Corps of Engineers:
EA: environmental assessment:
EIS: environmental impact statement:
FONSI: finding of no significant impact:
FWS: U.S. Fish and Wildlife Service:
NEPA: National Environmental Policy Act:
NESP: Navigation and Ecosystem Sustainability Program:
SEIS: supplemental environmental impact statement:
USGS: U.S. Geological Survey:
WRDA: Water Resources Development Act:
[End of section]
United States Government Accountability Office:
Washington, DC 20548:
[End of section]
December 9, 2011:
The Honorable Timothy Bishop:
Ranking Member:
Subcommittee on Water Resources and the Environment:
Committee on Transportation and Infrastructure:
House of Representatives:
The Honorable Jerry Costello:
Ranking Member:
Subcommittee on Aviation:
Committee on Transportation and Infrastructure:
House of Representatives:
The Mississippi River has long been a prime contributor to the
nation's physical and economic growth. As it flows from northern
Minnesota south to the Gulf of Mexico, the river carries a significant
volume of commerce, supplies water to the cities and industries along
its course, and sustains vital ecosystems in the water and on shore.
However, throughout its history--and most recently in 2011--the river
has also been a source of major floods that have caused widespread
damage to communities in its floodplain.[Footnote 1] Through
legislation, Congress has directed the U.S. Army Corps of Engineers
(Corps) to support Mississippi River navigation, provide flood
protection, and restore the river's environment. To fulfill its
navigation mission, the Corps employs a variety of structures designed
primarily to "train" the Mississippi River--diverting its flow of
water and sediment to scour the river bottom in order to maintain an
adequate navigation channel. The Corps relies heavily on these river
training structures in the Middle Mississippi, which is a 195-mile
stretch that extends from where the Missouri River joins the
Mississippi River above St. Louis, Missouri, to where the Ohio River
enters the Mississippi River at Cairo, Illinois. The Middle
Mississippi is an integral part of a river system that handles nearly
500-million tons of waterborne commerce annually.
The primary purpose of the Corps' river training structures is to
maintain the channel's depth when water flow is low, but some
researchers contend that the structures have unintended consequences
during higher-flow events, in particular those resulting in floods.
Studies published in the 1970s discussed the idea that the
accumulation of hundreds of river training structures in the Middle
Mississippi might unintentionally cause large volumes of water to
"back up" in the river, thus increasing the height of flood waters. A
recent series of floods in the St. Louis region in 2008 rekindled this
issue. In support of their claims, some researchers have analyzed
trends over time between the height of the water's surface (the
river's "stage," commonly measured in feet) and the volume and speed
of its flow (the river's "discharge," commonly measured in cubic feet
per second). In addition to these concerns about the structures'
hydrologic effects,[Footnote 2] critics of the structures claim that
the Corps' assertions of environmental benefits produced by certain
structures are unproven and not worth the risk of higher flood stages.
In contrast, the Corps and other researchers contend that the
structures produce the desired navigational and environmental benefits
without increasing flood risk or severity.
In this context, you asked us to report on the Corps' use of river
training structures in the Middle Mississippi. Our objectives were to
examine (1) key requirements and directives that govern the Corps' use
of river training structures, (2) how the Corps has addressed key
federal and state environmental requirements in the use of river
training structures, (3) the extent to which the Corps has monitored
the hydrologic and environmental impacts of river training structures,
and (4) concerns that researchers have raised about the hydrologic and
environmental impacts of the Corps' river training structures and how
the Corps has responded to these concerns.
To address the first objective, we reviewed relevant provisions in key
federal and state laws, regulations, and guidance that govern the
Corps' use of river training structures. We determined these laws,
regulations, and guidance to be key because they authorize
construction of river training structures and relate to flooding and
environmental impacts. We conducted interviews with Corps officials--
specifically, agency engineers and attorneys, as well as biologists
and other scientists. Our work focused on the Corps' St. Louis
District and its management of the Middle Mississippi. We also
interviewed officials from the Corps' national headquarters, its
Mississippi Valley Division, and the division's other five districts.
To address the second and third objectives, we reviewed the Corps'
various assessments of its river training structures and compared them
to the requirements we identified. We examined project documentation
to determine how the Corps addressed these requirements. We also
obtained in writing the Corps' legal views on how it has complied with
National Environmental Policy Act (NEPA)[Footnote 3] requirements with
respect to its river training structures constructed under the project
to operate and maintain the navigation channel. In addition, we
interviewed officials with the U.S. Fish and Wildlife Service (FWS),
state resource agencies, and several nongovernmental organizations to
obtain their views. To address the fourth objective, we conducted a
detailed literature review of scientific periodicals and government-
sponsored research on the effects of river training structures. We
used this review--along with interviews with officials from the Corps,
FWS, the U.S. Geological Survey (USGS), and state resource agencies,
as well as other researchers not affiliated with these parties--to
compile the key concerns that have been raised about the structures'
hydrologic and environmental impacts. We then solicited the Corps'
response to the concerns identified by non-Corps parties. We also
conducted structured interviews with a group of 16 experts in the
fields of river engineering and water resources to obtain their
comments on these concerns and to identify ways in which they might be
resolved. We identified these experts through recommendations made
during our interview process and by soliciting recommendations from
relevant organizations, such as the National Research Council's Water
Sciences and Technology Board and the American Society of Civil
Engineers. A more detailed description of our scope and methodology is
presented in appendix I.
We conducted this performance audit from September 2010 through
December 2011 in accordance with generally accepted government
auditing standards. Those standards require that we plan and perform
the audit to obtain sufficient, appropriate evidence to provide a
reasonable basis for our findings and conclusions based on our audit
objectives. We believe that the evidence obtained provides a
reasonable basis for our findings and conclusions based on our audit
objectives.
Background:
The Corps first became responsible for supporting Mississippi River
navigation under an act passed by Congress in 1824. Within the Corps,
responsibility for managing the river rests with its Mississippi
Valley Division, headquartered in Vicksburg, Mississippi. The
division's St. Louis District manages about 300 miles of the river,
including the Middle Mississippi. For planning purposes, the river as
a whole is divided into two parts: (1) the Upper Mississippi, which
extends from northern Minnesota to the Ohio River confluence and
includes the Middle Mississippi; and (2) the Lower Mississippi, which
begins at the Ohio River confluence and empties into the Gulf of
Mexico. Figure 1 shows the boundaries of the six Corps districts in
the Mississippi Valley Division, as well as the Upper, Middle, and
Lower Mississippi.
Figure 1: Management Area of the Six Districts within the Corps'
Mississippi Valley Division:
[Refer to PDF for image: illustrated map]
Upper Mississippi River:
St. Paul District;
Rock Island District.
Middle Mississippi River:
St. Louis District.
Lower Mississippi River:
Memphis District;
Vicksburg District;
New Orleans District.
Source: GAO adaptation of U.S. Army Corps of Engineers map.
[End of figure]
River training structures have been used in the Middle Mississippi for
more than 170 years; for example, they began to appear in the St.
Louis area in the 1830s. However, significant construction in the
Middle Mississippi commenced with the increased involvement of the
federal government in the latter part of the 19th century. From 1879
to 1930, Congress passed a series of acts authorizing the Corps to
create and maintain a navigation channel through the Mississippi River
of sufficient depth to support year-round navigation. In the Middle
Mississippi, the Corps' "Regulating Works Project" provides for agency
activities that support the operation and maintenance of the
authorized channel, such as dredging sediment from the bottom of the
channel and constructing river training structures to better shape it
for navigation.
The Corps typically builds river training structures by piling large
stones on the river bottom in various configurations. The most common
type of structure is a wing dike (also known as a wing dam or spur
dike), which extends from one riverbank at an angle roughly
perpendicular to river flow. See figure 2 for a photograph of wing
dikes in the Middle Mississippi.
Figure 2: Wing Dikes in the Middle Mississippi:
[Refer to PDF for image: photograph]
Source: U.S. Army Corp of Engineers.
Arrows indicate locations of wing dikes in the photograph.
[End of figure]
According to the Corps, wing dikes have been used on the Middle
Mississippi in various forms since at least 1838. They are designed to
maintain a navigable channel by concentrating river flow in the
channel. This focuses the water's energy and suspended sediment,
scouring the river bottom and thereby deepening the channel. These
structures are able to maintain the navigation channel because the
Mississippi River is an alluvial valley, which means that the river
bottom is made of soil and sand rather than rock and stone.
Consequently, the riverbed is constantly shifting in response to the
force of water and suspended sediment. River training structures
harness these forces and redirect them into the navigation channel.
This allows barges to travel the river throughout the year, even when
the river is low, while reducing the amount of dredging that is
required to maintain the channel's authorized depth. Figure 3
illustrates the scouring effect a wing dike has on the river bed,
resulting in a deeper navigation channel.
Figure 3: Simplified Illustration of a River Cross-Section before and
after Installing a Wing Dike:
[Refer to PDF for image: 2 illustrations]
A--Natural;
B--with dike.
Source: GAO analysis.
[End of figure]
In the last 20 years the Corps has begun to use new types of
structures, known as bendway weirs and chevrons, to further train the
Middle Mississippi. Since 1990, the Corps has used bendway weirs,
which are specialized dikes placed on the outside of a river bend.
These structures are angled upstream and are positioned entirely under
water so that navigation traffic may pass over them. They are designed
to redirect flows to the inside of the bend, thus widening the
navigation channel and preventing it from migrating toward the outside
of the bend. See figure 4 for an illustration of bendway weirs.
Figure 4: Illustration of Submerged Bendway Weirs on the Outside of a
River Bend:
[Refer to PDF for image: photograph]
Source: U.S. Army Corp of Engineers.
Arrows indicate locations of wing dikes in the photograph.
[End of figure]
After 2000, the Corps introduced chevrons--arch-shaped dikes placed
with their curved arches pointed upstream. They are designed to split
the river's downstream flow, thereby scouring the main navigation
channel while creating a secondary channel near the bank. According to
Corps documents and other studies, chevrons have the added benefit of
promoting different kinds of aquatic habitat around the structures and
in the secondary channels. See figure 5 for a photograph of three
chevrons in the St. Louis harbor.
Figure 5: Chevrons in the St. Louis Harbor:
[Refer to PDF for image: photograph]
Source: U.S. Army Corp of Engineers.
Arrows indicate locations of wing dikes in the photograph.
[End of figure]
Like chevrons, wing dikes can be built as a series of similar
structures, known as a dike field, and are typically erected no higher
than half bankfull--the stage when water is halfway up the river's
banks. This is approximately 15 feet on the St. Louis gauge, with
flood stage at St. Louis beginning at 30 feet. Bendway weirs are
placed lower in the channel, and according to the Corps, are always
submerged.
According to Corps documents, there are currently more than 1,375 wing
dikes, bendway weirs, chevrons, and similar structures[Footnote 4] in
the Middle Mississippi's 195 river miles. Of this total, about 175 are
bendway weirs. The type and pace of construction of river training
structures has varied over time. For example, the St. Louis District
built almost 450 such structures in the late 19th century, and another
250 in the 1930s; it constructed 150 bendway weirs from 1990 to 2000.
The current pace of construction of these structures has slowed
relative to the past, but the St. Louis District continues to repair
and modify existing structures and has built some new ones. For
example, from 2003 to 2010 the district constructed 23 chevrons in the
Middle Mississippi, including 3 in the St. Louis harbor.
While not the subject of this review, it is important to note that the
Corps uses other structures to fulfill its navigation and flood
protection missions along the length of the Mississippi River. These
additional structures include:
* Levees and floodwalls. Levees are earthen barriers built parallel to
the river for flood protection, and floodwalls are artificial barriers
that give additional protection to populated areas. Both types of
structures narrow the river's floodplain.
* Dams and locks. Dams are structures built across the entire width of
the river to create pools that increase the depth of the river for
navigation. They are used above the Middle Mississippi, where
discharges are typically smaller relative to the rest of the river.
Locks are gated chambers that allow navigation traffic to pass through
the wall of a dam.
* Revetments. Revetments are concrete matting or graded stone placed
on riverbanks to stabilize them and prevent erosion. Revetments keep
the river in a fixed position--without them, the river's natural
tendency to meander could endanger lands and structures, including
levees, in the floodplain.
Assessments of the impacts of river training structures rely upon both
hydrologic and hydraulic research. Hydrology is the study of the
movement, distribution, and quality of water, and includes the study
of flooding. Hydrologic factors explain how (and how much) water
enters a river system. Such factors include upstream rainstorms, snow
melt, and runoff. In contrast, hydraulic factors are the physical
forces that govern how water and sediment are conveyed once they enter
a river system. Thus, the primary effect of river training structures
is hydraulic, because they deflect water (and sediment) into the
navigation channel. However, the structures' hydraulic and hydrologic
effects can be linked. Specifically, if structures' hydraulic effects
increase river stage, the structures could contribute to an overall
hydrologic effect.
The Corps and USGS have collected various types of historical
hydrologic data on the Mississippi River through different approaches.
For example, river stages have been measured daily at St. Louis since
1861. Because these measurements consist of river stage measured on a
stream gauge, they are more straightforward than discharge
measurements, which require accurate readings of flow velocity, river
width, and river depth--the latter two measurements, when multiplied,
form the river's cross-sectional area, which determines the volume of
flow it can convey. The Corps took most discharge measurements at St.
Louis until 1933, using a variety of devices to record the speed of
the river's flow. These devices included surface floats, double
floats, rod floats, and ultimately current meters.[Footnote 5] USGS
assumed discharge measurement duties at St. Louis in 1933, and began
operating the St. Louis stream gauge station to record continuous
stage and discharge measurements. From 1933 to the early 2000s, USGS
used Price current meters suspended from bridges--an improvement over
earlier devices and methods--to measure discharge, before adopting
even more precise instrumentation and methodology that is used today.
River Training Structures Must Adhere to Key Federal and State
Requirements and Corps Guidance:
Key federal laws provide the Corps with the authority to construct and
use river training structures in the Middle Mississippi for navigation
and environmental purposes. In addition, in constructing these
structures the Corps must comply with the environmental requirements
of other key federal laws such as NEPA and the Clean Water Act, as
well as applicable state requirements. Further, over a long history of
using these training structures, the Corps has gained significant
institutional knowledge that it has incorporated into guidance that
its districts consult when planning, constructing, and maintaining
these structures.
Key Federal Laws Provide the Corps with Authority to Use River
Training Structures:
The following key federal laws provide the Corps the authority to use
river training structures in the Middle Mississippi.[Footnote 6]
Rivers and Harbors Acts.[Footnote 7] The Rivers and Harbors Acts are a
series of laws dating back to the 1800s that authorize the Corps to
build and maintain public works projects and undertake other projects
in the nation's rivers and harbors. Among other things, these acts
have required the Corps to maintain a navigation channel in the
Mississippi River since 1878. The Rivers and Harbors Acts of 1927 and
1930 are of particular importance because they require the Corps to
establish the current 9-foot navigation channel. Specifically, the
1927 act required the Corps to establish this depth for the navigation
channel from the northern boundary of St. Louis to the mouth of the
Ohio River near Cairo, Illinois, and to establish another 9-foot
navigation channel from Cairo to the Head of Passes in Louisiana. The
1930 act establishes a similar channel from Minneapolis, Minnesota, to
the mouth of the Illinois River. The Corps meets these requirements
through the use of river training structures, in conjunction with
locks, dams, revetments, and periodic dredging of the river bed.
Water Resources Development Acts.[Footnote 8] The Water Resources
Development Acts (WRDA) govern various aspects of conservation and
development of water resources and, as the Rivers and Harbors Acts did
previously, authorize the construction of water resources projects,
including improvements to rivers and harbors of the United States.
Several WRDA provisions are particularly relevant to the use of river
training structures in the Middle Mississippi. For example, beginning
in 1986, WRDA authorizes the Corps' Environmental Management Program,
a joint federal-state partnership to restore and enhance the ecology
of the Upper Mississippi. The 1990 WRDA requires the Corps to consider
environmental protection as one of the primary goals for planning,
design, construction, operations, and maintenance of its water
resources projects. WRDA 2007 authorizes the Corps to develop
ecosystem restoration projects within the Upper Mississippi-Illinois
River waterway. These projects are administered under the Corps'
Navigation and Ecosystem Sustainability Program (NESP), a program
designed to promote navigation efficiency and ecological restoration.
River Training Structures Must Comply with Applicable Federal and
State Environmental Requirements:
In using river training structures in the Middle Mississippi, the
Corps must comply with the applicable environmental requirements of
key federal laws, as well as state and other requirements. These key
laws and requirements include the following:
National Environmental Policy Act.[Footnote 9] NEPA requires an agency
to prepare a detailed statement on the environmental impacts of any
"major federal action" significantly affecting the environment.
Regulations promulgated by the Council on Environmental Quality
implementing NEPA generally require an agency to prepare either an
environmental assessment (EA)[Footnote 10] or an environmental impact
statement (EIS).[Footnote 11] Agencies may prepare an EA to determine
whether there is a significant potential impact on the environment,
which would necessitate the preparation of an EIS. However, if the
agency, in its EA, determines there are no significant impacts from
the proposed action, then an agency should prepare a finding of no
significant impact (FONSI). NEPA regulations state that federal
agencies shall, to the maximum extent possible, encourage and
facilitate public involvement in decisions that affect the quality of
the human environment. Under these regulations, agencies must provide
a public comment period for a draft EIS; while there is no
corresponding requirement for an EA, agencies may provide a public
comment period. We reported in March 2010 that the Corps does not have
clear guidance concerning whether it will provide a public comment
period for draft EAs, and recommended the agency develop such
guidance.[Footnote 12] According to Corps officials, the agency is
presently developing such clarifying guidance. St. Louis District
officials said that their practice is to provide a public comment
period on any EA prior to finalizing a finding of no significant
impact.
Once an agency has prepared an EIS for a project, supplemental NEPA
documentation is sometimes required. The Council on Environmental
Quality's regulations require supplemental documentation when an
agency "makes substantial changes in the proposed action" or "[t]here
are significant new circumstances or information" relevant to
environmental concerns and bearing on the proposed action or its
impacts.[Footnote 13] A council document issued in 1981 suggests that
if the EIS concerns an ongoing program and is more than 5 years old,
it should be carefully reexamined to determine if a supplement should
be prepared.[Footnote 14] An agency must take a "hard look" at the new
information and project changes to determine if a supplemental EIS
(SEIS) is needed; an EA may be used to do so. Similarly, the Corps'
own NEPA implementing regulations require the district commander to
"review existing NEPA document(s) to determine if there are new
circumstances or significant impacts which warrant the preparation of a…
supplement to the EIS."[Footnote 15] Then, after review of the new
information and project changes, the Corps will determine whether to
prepare an additional EA or SEIS.[Footnote 16] An EA is recommended if
there are, among other things, "changes in environmental impacts
[that] were not considered" in the original NEPA documentation.
[Footnote 17] An EA or SEIS may also be used to ensure site-specific
impacts and alternatives are evaluated when an initial EIS is broad or
programmatic in nature. Additional, site-specific analysis is required
when the original EIS did not provide the required analysis and left
gaps that could include significant impacts.[Footnote 18] Thus, when
unaddressed impacts are brought to light by new information or major
changes in the operation or maintenance of Corps projects, the Corps
is required to prepare supplemental NEPA documentation.
Clean Water Act.[Footnote 19] The Corps is also subject to many
requirements of the Clean Water Act, which includes the goal of
eliminating the addition of pollutants to waters of the United States.
The Clean Water Act requires, among other things, that projects
involving placement of dredged or fill material in federally regulated
waters must obtain a permit, known as a Department of the Army Section
404 permit or simply a "dredge or fill" permit. With respect to the
Corps' own activities triggering a dredge or fill permit, the agency's
practice is generally to document that the activities are covered by a
nationwide permit,[Footnote 20] or if not, to issue a permit-
equivalent. In doing so, the Corps project team prepares a document
evaluating the project's compliance with EPA-promulgated guidelines
[Footnote 21] for the placement of fill material in federally
regulated waters, including a determination of cumulative effects on
the aquatic ecosystem, as well as to provide information demonstrating
compliance with state water quality standards. The Corps regulatory
section generally makes this document, known as a Section 404(b)(1)
evaluation or statement of findings, available for public review as
part of the public notice of the permit application.
Fish and Wildlife Coordination Act.[Footnote 22] The Fish and Wildlife
Coordination Act authorizes the Secretary of the Interior to, among
other things, provide assistance to, and cooperate with, federal,
state, and public or private agencies and organizations in the
development, protection, rearing, and stocking of all species of
wildlife and their habitat; in minimizing damages from overabundant
species; and in providing public shooting and fishing areas.
Amendments to this law enacted in 1946 require consultation with FWS
and the fish and wildlife agencies of states where the "waters of any
stream or other body of water are proposed or authorized, permitted or
licensed to be impounded, diverted, the channel deepened. . . or
otherwise controlled or modified" by any federal agency.[Footnote 23]
Consultation is to be undertaken for the purpose of preventing loss of
and damage to wildlife resources, among other reasons.
Endangered Species Act.[Footnote 24] The Endangered Species Act
requires that federal agencies ensure that any action they authorize,
fund, or carry out is not likely to jeopardize the continued existence
of a species protected under the act. To fulfill this responsibility,
the agencies must, under some circumstances, formally consult with FWS
when their actions may affect listed species or habitat identified as
critical to the species' survival. Formal consultations generally
result in the issuance of biological opinions by FWS. The biological
opinion contains a detailed discussion of the effects of the action on
listed species or critical habitat and FWS's opinion on whether the
agency action is likely to jeopardize the continued existence of the
species. In cases where a project as proposed is likely to either
jeopardize the species or cause the destruction or adverse
modification of its critical habitat, the opinion will provide
"reasonable and prudent" alternatives to avoid jeopardy or adverse
modification that FWS believes the agency could take in implementing
the action. Additionally, biological opinions often contain provisions
directing an agency to monitor and report on the effects of its action
on listed species.[Footnote 25]
Executive Order 11988.[Footnote 26] Executive Order 11988, Floodplain
Management, was signed by the President in 1977. The executive order
requires, among other things, that agencies determine whether a
proposed action will occur in a floodplain, and if so, consider
alternatives to avoid adverse effects and incompatible development in
the floodplains and take actions to minimize potential harm to the
floodplain. Under the executive order, the floodplain is, in relevant
part, defined as including the lowland and relatively flat areas
adjoining inland waters, but does not include the river channel. The
executive order also requires each agency to issue or amend existing
regulations and procedures within 1 year to comply with the order; the
regulations and procedures are to require the construction of federal
structures and facilities to be in accordance with the standards and
criteria and to be consistent with the intent of those promulgated
under the National Flood Insurance Program, the primary federal
government initiative supporting flood insurance for communities
meeting minimum conditions. The National Flood Insurance Program
requires that participating communities ensure that construction,
fill, and certain other activities in the floodway do not cause an
increase in flood levels,[Footnote 27] but the executive order,
however, was focused on the land portion of floodplains rather than
the river channel and does not import the prohibition on floodway
encroachment to federal agencies. The Corps regulation implementing
the executive order specifies Corps policy and procedures for
projects, including operation and maintenance activities, in the
floodplain.[Footnote 28] The Corps regulation defines regulatory
floodway as "the area regulated by Federal, State or local
requirements; the channel of a river or other watercourse and the
adjacent land areas that must be reserved in an open manner, i.e.,
unconfined or unobstructed either horizontally or vertically to
provide for the discharge of the base flood[Footnote 29] so the
cumulative increase in water surface elevation from encroachment does
not exceed one foot as set by the National Flood Insurance Program."
State requirements. In addition to complying with federal
requirements, the Corps' use of river training structures must also
comply with applicable state requirements. Specifically, federal
agencies conducting projects requiring federal permits or licenses
generally must obtain certification from the relevant state that the
project will not cause or contribute to violations of the state's
water quality standards. In the Middle Mississippi, if a federal
project in Missouri or Illinois complies with the conditions of
certain nationwide permits, as well as conditions of the relevant
state's blanket water quality certification, then additional
certification is generally not needed. Moreover, although states may
set floodway standards, this generally does not impose a requirement
on the Corps' use of river training structures.[Footnote 30]
The Corps Has Internal Guidance That Applies to the Use of River
Training Structures:
The Corps has internal guidance, informed by institutional knowledge,
that further governs its use of river training structures in the
Middle Mississippi. The primary guidance for the design of river
training structures is the Corps' engineering manual.[Footnote 31] The
manual's section on training structures covers topics such as
determining their length and height and the size of the stones used in
constructing them. It also addresses flood control, cautioning
structure designers to ensure that the amount of channel contraction
does not unduly increase flood heights; discusses the performance and
evaluation of training structures; and lists studies and factors that
should be considered in the planning and design of training
structures, including the modeling of such structures to help predict
their impacts. In several places, the manual cites institutional
knowledge as a factor that should be considered in designing and
constructing training structures. For example, the manual states that,
through experience and judgment, an engineer can evaluate various
sections of the river that maintain adequate depths naturally and use
that information to determine how to apply it to other sections.
Corps guidance also includes its policy for internal reviews of all
Civil Works projects.[Footnote 32] The policy establishes various
levels of review, including district-level quality control review,
agency technical review, and independent external peer review. The
policy applies to all Civil Works projects "from initial planning
though design, construction, and operation, maintenance, repair,
replacement, and rehabilitation." In addition, Mississippi Valley
Division regulations establish, among other things, required approvals
and reviews for river training structures and other channel
improvements in the Mississippi River and key tributaries.[Footnote
33] For example, the regulations require each district's "general
plan" to provide a general outline of proposed channel improvements,
such as proposed location and type of training structures. These plans
are to be approved by a Division team, which serves as the agency's
technical review under the Corps' review policy.
In addition, the St. Louis District provided us with a written
description of the process they use to assess the need for new
training structures and then build and monitor them. This process is
not currently documented in the Corps' official guidance. According to
the description provided by the district, the process includes several
steps, such as (1) assessing river conditions and identifying sections
of the river that have resulted in navigation problems, (2) designing
structures using physical models of the river, (3) coordinating with
key stakeholders, and (4) monitoring structures before and after
construction. The description states that this process is consistent
with the process that has been used throughout the Mississippi Valley
Division for the past 50 years.
The Corps Has Addressed Some but Not All of the Environmental
Requirements for River Training Structures:
The Corps has conferred with stakeholders on environmental impacts and
has assessed these impacts to some extent, but has not prepared
additional analyses--such as an EA--to assess site-specific impacts
and alternatives, new information, and project changes to determine if
a SEIS is required. The Corps also has not obtained Clean Water Act
permits or state water quality certifications for river training
structures as required.
The Corps Has Conferred with Stakeholders Prior to Constructing River
Training Structures:
In accordance with the Fish and Wildlife Coordination Act and the
Endangered Species Act, the Corps has engaged in consultation with FWS
about the environmental impacts of river training structures.
Specifically, the Corps' St. Louis, Rock Island, and St. Paul
Districts consulted with FWS in the 1990s on the operations and
maintenance of the 9-foot navigation channel. In its 2000 biological
opinion, FWS determined that the operations and maintenance project
jeopardizes the pallid sturgeon--a large native fish that FWS placed
on the endangered species list in 1990--and results in harm to the
interior least tern--a small bird that was placed on the endangered
species list in 1985--in the Middle Mississippi.[Footnote 34] To
prevent jeopardy for the pallid sturgeon, FWS's biological opinion
instructs the Corps to (1) conduct a habitat study in the Middle
Mississippi, (2) facilitate development of a conservation and
restoration plan, (3) implement a long-term program of aquatic habitat
restoration, and (4) begin short-term implementation of aquatic
habitat restoration measures. To minimize harm to the least tern, the
opinion instructs the Corps to (1) modify training structure
maintenance projects to maintain flow between sandbars and the shore
and to reduce conversion of sandbar habitat to trees; (2) evaluate,
and implement where appropriate, techniques that use dredge material
to restore or enhance sandbar habitat and aquatic habitat; and (3)
reduce the accretion of new and existing sandbars to the bank and
reduce tree colonization on those sandbars.
In addition to requirements for consultation and other actions to
prevent harm to endangered species, the St. Louis District is required
to submit annual reports to FWS on its implementation of the
biological opinion's reasonable and prudent alternatives. According to
FWS, the St. Louis District is several years behind in providing these
annual reports. In addition, the consultation culminating in the 2000
biological opinion did not include individual, site-specific effects
or new construction impacts. According to the opinion and a Corps
document, site-specific effects and new construction impacts for river
training structures are to be handled under separate consultations,
referred to as tier II biological assessments. The Corps provided us
with examples of such assessments issued in 2010 and 2011.
According to officials at FWS and the state resource agencies in
Illinois and Missouri, the St. Louis District confers with them prior
to constructing river training structures. According to officials at
the FWS field office that works with the St. Louis District, the
district coordinates with them through activities conducted under the
Fish and Wildlife Coordination Act, as well as through the
implementation process for the 2000 biological opinion. This
interaction occurs through the district's River Resources Action Team,
which coordinates and prioritizes projects in the Middle Mississippi,
including those related to the biological opinion, and conducts an
annual inspection tour of the river. Additionally, the Corps has
consulted with the states prior to constructing river training
structures. According to officials at the Illinois and Missouri
Departments of Natural Resources and the Missouri Department of
Conservation, the St. Louis District solicits their comments on
proposed projects and involves them in river planning studies. As part
of the St. Louis District's planning process, it invites these
stakeholders to its Applied River Engineering Center[Footnote 35] for
physical modeling demonstrations, where district engineers describe
proposed structures and solicit comments from stakeholders. Officials
from both states told us they believe that the level of coordination
is sufficient.
The Corps Has Not Prepared the Additional Environmental Analyses
Required by NEPA:
The St. Louis District has not performed the additional analyses of
environmental impacts for river training structures that it has
constructed in the last three decades as NEPA requires, but instead
has continued to rely primarily on an EIS prepared more than 35 years
ago. Specifically, in 1976, the St. Louis District issued the Final
Environmental Statement: Mississippi River between the Ohio and
Missouri Rivers (Regulating Works).[Footnote 36] The 1976 EIS focuses
on the operation and maintenance of the Middle Mississippi navigation
channel, including dikes, revetments, and any necessary dredging. It
broadly discusses each component of its recommended plan, and
discusses at a high level the implementation of dikes in general. It
does not describe the environmental effects of river training
structures or specify any design criteria or location for any
structures. The EIS states that dikes could lead to degradation of the
riverbed and aquatic organisms and acknowledges that some impacts of
the 9-foot channel project were "not… adequately assessed" or "not yet
fully understood."[Footnote 37] It also recognizes that the river is
an ever-changing environment and states that a reassessment of project
impacts would likely be necessary within 5 years.[Footnote 38] The EIS
briefly considers broad alternatives to the Regulating Works Project,
namely no action; use of locks and dams; a change in project
authorization to incorporate fish and wildlife enhancement; and the
existing operation and maintenance activities, which formed the
adopted plan. The EIS concludes that the actions proposed by the
Regulating Works project do not significantly impact the river's
endangered species, among other things.
In the 35 years since the Corps issued its EIS, the St. Louis District
has constructed new river training structures in the Middle
Mississippi and intends to continue building such structures in the
future as needed. For these new river training structures, the St.
Louis District has continued to rely primarily upon the 1976 EIS as
adequate for NEPA compliance. However, since 1976, the picture of
potential impacts of these structures on the river environment has
changed in some important respects. First, several river species have
been listed as endangered (e.g., the least tern and the pallid
sturgeon) and significantly more data has been developed on their
populations as well as impacts of training structures on habitat for
these and other species. For example, according to FWS's 2000
biological opinion, river training structures affect natural river
processes, harming the least tern and pallid sturgeon. The 1976 EIS
does not reflect today's scientific understanding of the effect of
river training structures on these species. The 1976 EIS also does not
reflect the relative significance of various types of river habitat
for other native species, given the losses in habitat diversity
documented in FWS's 2000 biological opinion and a 2004 Corps
document.[Footnote 39] Second, the St. Louis District has expanded the
types of river training structures it uses in the Middle Mississippi.
For example, the district began using bendway weirs in 1990 and
chevrons after 2000, whereas the 1976 EIS focuses primarily on the use
of wing dikes. Corps documents suggest that each of these types of
river training structures may have different environmental impacts,
but St. Louis District officials told us that while configurations of
river training structures have evolved over time, the purpose and
function of these structures themselves has changed very little.
Finally, the 1976 EIS does not provide any information on site-
specific structures or locations and discusses the environmental
effects only at a high level. Without site-or location-specific
information, the Corps has not documented to the public its
consideration of such impacts and potential mitigation. Because the
St. Louis District has not prepared any additional NEPA documents
since 1976, such as an EA or SEIS, we believe that the Corps has not
fully implemented the requirements of NEPA for river training
structures in the Middle Mississippi. The absence of additional NEPA
analyses, we believe, limits opportunities for the Corps to evaluate
new environmental circumstances and information that have arisen since
1976.
The lack of additional NEPA analysis by the St. Louis District is also
inconsistent with Corps regulations and the practices of other
districts. Corps regulations require the St. Louis District commander
to "review existing NEPA document(s) to determine if there are new
circumstances or significant impacts which warrant the preparation of a…
supplement to the EIS." However, we found that for river training
structures this has generally not happened. The Corps' position is
that the agency has taken the requisite "hard look" at whether there
are new or significant changes that would require additional NEPA
documentation, and so far as the Corps has been able to determine to
date, changes have not risen to a level of significance that would
justify or require the preparation of a SEIS. The Corps produced one
documented internal review, from 1994, of whether additional NEPA
documents were needed for the Regulating Works Project.[Footnote 40]
The review, however, did not describe what changes the Corps believed
had taken place, or why it considered those changes to be
environmentally insignificant.[Footnote 41] According to Corps
officials, the St. Louis District has had discussions and briefings on
this issue, and NEPA considerations have been discussed with the
district commander at the budget, design, and construction phases for
specific river training structures. However, the district did not
provide documentation to us that demonstrated these discussions.
Similarly, we found that the St. Louis District's approach for
preparing additional analyses is inconsistent with other Corps
districts. For example, the Rock Island District, which is the
district immediately to the north of the St. Louis District, has
prepared eight EAs since 1992 for river training structure
construction or modifications under its channel operation and
maintenance authority. One of these EAs noted that the Rock Island
District's EIS[Footnote 42] for operation and maintenance of the 9-
foot channel, prepared in 1974, does not address site-specific new
construction of river training structures. As a result, the Rock
Island District prepared additional NEPA documentation to address
potential impacts of its construction. In addition, the Rock Island
District provided the public an opportunity to comment on this EA
before deciding whether or not to prepare an EIS.
In a written response to our inquiries about this issue, the Corps'
Chief Counsel stated that the agency strongly believes, "based on all
information available to [the Corps] at this time," that it is in full
compliance with NEPA with regard to river training structures. The
written response further stated, however, that "in the spirit of" NEPA
regulations the Corps will voluntarily perform an additional EA for
river training structures that "will determine whether there are
undisclosed and currently unknown significant effects on the human
environment that might require additional analysis and documentation."
Further, the written response stated that the Corps will make an
objective and formal determination of whether to prepare a SEIS after
the EA is completed but did not state whether it would make a draft of
the EA available for public comment. The written response also noted
that the Corps cannot commit to a specific time frame for completion
of the EA, since no funds have been budgeted for it in fiscal year
2012.
The Corps Has Not Obtained Clean Water Act Permits:
As previously discussed, the Corps is obligated to obtain Clean Water
Act permit-equivalents for placement of fill in federally regulated
waters and obtain associated water quality certifications from
relevant states, unless a nationwide permit applies. However, the St.
Louis District has not obtained these permits for river training
structures constructed under the Corps' operation and maintenance
authority. Instead, according to district officials, the agency builds
new river training structures under its authority to maintain the
river channel, and therefore they are considered to fall under a
nationwide permit for maintenance issued by the Corps' regulatory
branch. In addition, St. Louis District officials told us they do not
need the permit-equivalent because they are operating under the
nationwide permit.
However, the Corps has not demonstrated that the construction of new
river training structures, which typically involves the placement of
thousands of tons of rock into the river, meets the requisite
conditions for the nationwide permit for maintenance. This nationwide
permit authorizes "the repair, rehabilitation or replacement of any
previously authorized, currently serviceable, structure, or fill," and
"minor deviations in the structure's configuration or filled area,
including those due to changes in materials, construction techniques,
or current construction codes or safety standards that are necessary
to make the repair, rehabilitation or replacement." The permit further
notes that "the placement of riprap must be the minimum necessary to
protect the structure or to ensure the safety of the structure."
[Footnote 43] St. Louis District officials did not provide us any
evidence that would explain how new river training structures are
consistent with the nationwide permit's scope. Moreover, the Corps'
regulations applicable to all nationwide permits provide that no
activity is authorized under any nationwide permit that is likely to
jeopardize the continued existence of a threatened or endangered
species or that will destroy or adversely modify the critical habitat
of such species. As previously discussed, FWS determined in its 2000
biological opinion that the Corps' channel maintenance activities
jeopardize the pallid sturgeon, among other species. The St. Louis
District could not explain to us how a nationwide permit would be
applicable to project operations under these circumstances.[Footnote
44] Furthermore, officials at another Mississippi River Corps district
that we contacted told us that the nationwide permit for maintenance
is not applicable for new construction of river training structures
and as a result they do not use such a permit in their district. In
light of these discrepancies, we believe that the St. Louis District
has not obtained the permits required by the Clean Water Act,
including obtaining the required state water quality certification for
its river training structures.
The Corps Has Routinely Monitored the Hydrologic Impacts of River
Training Structures after Construction, but Has Not Routinely
Monitored Their Environmental Impacts:
For river training structures in the Middle Mississippi, the Corps has
conducted preconstruction physical and numerical modeling to assess
the potential hydraulic impacts of the structures and has routinely
monitored the hydrologic impacts after construction through data
collection and observation, among other activities. In contrast, the
Corps has not routinely monitored postconstruction environmental
impacts of its river training structures. The Corps has, however,
conducted or contracted for a number of studies on specific
environmental effects of its river training structures.
The Corps Has Conducted Preconstruction Modeling to Assess Hydraulic
Impacts:
Prior to construction, the Corps has conducted physical and numerical
modeling to assess the potential hydraulic impacts of proposed new
river training structures and proposed modifications to existing
structures. For example, at its Applied River Engineering Center, the
Corps has assessed hydraulic impacts of river training structures by
building small-scale physical models to help determine the impact that
these structures might have on a given river section, such as changes
in flow and sedimentation patterns.[Footnote 45] Corps officials told
us that the Corps builds models for specific reaches of the river, to
evaluate the effectiveness of the various river training structures
prior to constructing them. The Corps uses field data, such as
discharge, velocity, and sediment volume, to calibrate its models. The
models are then run through a series of tests to obtain results. Corps
engineers evaluate the results and refine the models, with input and
review from biologists, fisheries specialists, other water resource
scientists, the river industry, land owners, and other stakeholders.
The results are recorded in reports that are publicly available on a
Corps website.[Footnote 46] As of September 2011, the Corps' website
included 25 physical model reports that have been issued since 1994.
The Corps has also used physical models to solve problems such as
repetitive dredging and other navigation-related issues. For example,
in a report issued in 2004, the Corps built a physical model to
evaluate and propose design modifications to existing training
structures, and possibly introduce new training structures, for the
purpose of improving navigation conditions and reducing the need for
dredging in the St. Louis harbor.[Footnote 47] Figure 6 is a
photograph of a small-scale physical model similar to the one used in
the St. Louis harbor report.
Figure 6: Photograph of a Small-Scale Physical Model:
[Refer to PDF for image: photograph]
Source: U.S. Army Corp of Engineers.
Note: The model employed a horizontal scale of 1 inch equals 1,000
feet and a vertical scale of 1 inch equals 100 feet.
[End of figure]
The Corps has also at times used numerical models to assess the
potential hydraulic impacts of training structures prior to their
construction. Numerical models are computer programs that simulate the
behavior of a river section. Like physical models, numerical models
use field data from the actual section, such as river stage,
discharge, and cross-sectional width. The Corps runs these data
through a complex set of equations to produce quantitative estimates
of how the river will respond to changes, such as the addition or
modification of training structures. According to an official with the
Corps' Engineer Research and Development Center,[Footnote 48]
numerical models can run analyses in one, two, or three dimensions.
The two-and three-dimensional models can perform more complex
analyses, but on a shorter stretch of river than a one-dimensional
model. According to this official, the Corps commonly uses one-
dimensional models to analyze changes in the floodplain for a large
river section. Two-dimensional models can analyze lateral and
longitudinal velocities for a smaller river section, and three-
dimensional models can analyze vertical velocities for an even smaller
river section. Models can be used in tandem--for example, results from
three-dimensional modeling can be used to improve a two-dimensional
model. Numerical models are able to show the effects that training
structures have on the river as its flow goes around the structures,
including flow separation and sediment capture, the official told us.
In certain circumstances, the Corps has run numerical models in
conjunction with physical models to help it to obtain a clearer
picture of the expected results.
In contrast, the Corps has not assessed the potential hydrologic
impacts of proposed new river training structures or proposed
modifications to existing structures prior to their construction
because it believes the structures have no impact on flooding,
according to agency officials. According to Corps officials, both
physical and numerical models are limited in their ability to assess
hydrologic impacts of river training structures. For example,
according to these officials, small-scale physical models cannot be
used to predict changes in river stage. They said this is because of
the large differences in scale between the model and the actual size
of the river section being modeled. Because of these large
differences, it is not possible to measure very small changes in river
stage detected in the model and translate them into predicted changes
in actual river stage. In addition, there are other factors that may
impact river stage, such as bank vegetation, that are not feasible to
reproduce in a small-scale model, according to a St. Louis District
official responsible for modeling. As with physical models, a district
official told us that while numerical models could theoretically be
used to predict impacts of training structures on river stage prior to
construction, the Corps is not aware of a model study that has proven
this capability.[Footnote 49] Further, the official said that because
the Corps believes training structures have no impact on river stage,
the St. Louis District does not believe it is necessary to perform
numerical modeling for assessing river stage impacts.
According to the St. Louis District, along with physical and numerical
modeling, the Corps also monitors the section of the river where it
plans to build or modify training structures by collecting data,
including hydrographic surveys of the river bottom, velocities of the
river current, stages, and discharges. In addition, the Corps conducts
several reviews before constructing or modifying training structures.
Specifically, according to the St. Louis District, engineers
throughout the division review the proposals, as do federal and state
partner agencies, such as FWS, the Illinois Department of Natural
Resources, and the Missouri Department of Conservation, as well as the
navigation industry. In addition, Corps officials told us that all
training structure proposals undergo, at the general plan stage, a
formal review by a committee consisting of representatives from all
six districts in the Mississippi Valley Division. This is conducted
per division regulations establishing reviews and approvals, including
those under the Corps Civil Works Review Policy.
The Corps Routinely Monitors Postconstruction Hydrologic Impacts:
According to the St. Louis District, once training structures are
built, it routinely monitors their hydrologic impacts through several
methods. First, it collects data to measure the structures' effects
and to compare with preconstruction data. For example, St. Louis
District engineers conduct hydrographic surveys of the river bottom to
confirm that the structures have improved the channel's ability to
convey water and sediment. Also, according to Corps officials and
documents, the Corps collects and monitors discharge and other
relevant data with instruments that, for example, measure the velocity
of water at various depths or the height of water over a given
structure. Engineers also monitor stream gauges--37 operating on the
Middle Mississippi--both upstream and downstream of training
structures to determine whether river stage changed after construction
of particular training structures.
As part of its monitoring of stream gauges, the Corps conducts
"specific gauge analysis," which it defines as a graph of river stage
for a specific discharge at a particular gauging location plotted
against time. St. Louis District officials told us the Corps does this
to track changes in river stage over time and, in particular, to
determine if stage is trending upward or downward for a given
discharge. This analysis can help determine any cumulative impact of
river training structures on river stage. Conducting a specific gauge
analysis requires two steps. The first step is to develop a "rating
curve," which is a graph of a series of points that plots river stage
(measured in feet) against discharge (measured in cubic feet per
second) over time (usually 1 year). Once the points are plotted, a
line is fitted through them to create a rating curve for that year.
Figure 7 is an example of a rating curve for the St. Louis gauge in
1993, a year that saw heavy flooding on the Middle Mississippi. The
same technique is used to develop rating curves for each year of
interest.
Figure 7: 1993 Rating Curve for the St. Louis Gauge:
[Refer to PDF for image: line graph]
Graph plots the following:
Discharge (cubic feet per second, in thousands):
against:
Stage (feet).
Source: U.S. Army Corp of Engineers.
Note: This graphic is presented solely as an example of the Corps'
hydrologic monitoring. We did not attempt to independently reproduce
the information depicted.
[End of figure]
The second step is to use the rating curves developed in step one to
plot the river stage for specific discharges for each year. This is
done in a specific gauge analysis graph. Figure 8 shows such a graph
for the St. Louis gauge for a period starting in the early 1930s and
ending in the late 2000s.
Figure 8: Specific Gauge Analysis for the St. Louis Gauge:
[Refer to PDF for image: plotted point graph]
Graph plots the following:
Year:
against:
Stage (feet).
Discharge levels are represented in cubic feet per second.
Source: U.S. Army Corp of Engineers.
Note: This graphic is presented solely as an example of the Corps'
hydrologic monitoring. We did not attempt to independently reproduce
the information depicted.
[End of figure]
In determining any trends in river stage for the specific gauge
analysis in figure 8, one would need to pick a discharge amount, and
then draw a line through the points representing observed stages
associated with that discharge over a period of years to see if the
line is rising, falling, or remaining essentially flat over time. For
example, in observing the plotted river stages associated with the
300,000 cubic feet per second discharge--a level generally
corresponding with a stage of about 20 feet, which is well within the
river's banks--it appears that the trend in river stage has been
essentially flat. This indicates that this discharge amount resulted
in about the same river stage height in the 2000s as it did in the
1930s.
The second way the Corps monitors the hydrologic impacts of river
training structures is by physically observing them, according to
officials we spoke with. For example, they observe them to determine
whether there are any readily identifiable visual effects on flow. In
addition, a St. Louis District official said that a team of Corps
officials--which includes engineers, biologists, and other scientists-
-along with other key stakeholders, conduct an annual multiday
inspection tour that enables participants to observe training
structures up close and discuss the potential need for new structures.
Participating stakeholders include FWS, the Illinois Department of
Natural Resources, the Missouri Department of Conservation,
nongovernmental organizations such as the Nature Conservancy and the
Prairie River Audubon, and university faculty.
Third, for decades the Corps has conducted its own studies of the
impacts of structures on the shape of the channel and flooding after
construction. For example, the Corps issued a paper in 1964 that
presented, among other things, the variations in rating curves with
respect to time and stage and causes for some of the changes in the
stage-discharge relationship.[Footnote 50] The Corps conducted similar
studies in the 1970s, 1980s, and 1990s. Another study the Corps
completed in 2009 examined the limits of using specific gauge analysis
to analyze the effects of river training structures on flood heights.
A more recent Corps study in 2011 looked at the effects of bendway
weir construction on the shape of the channel. Specifically, this
study examined 22 bendway weir fields, all but 1 located in the Middle
Mississippi, over 5 periods (1976, 1982, 1986, 2005, and 2007) to
compare certain parameters before and after installation.
The Corps Does Not Routinely Monitor Environmental Impacts after
Construction but Has Conducted Various Studies:
According to Corps officials, the St. Louis District does not
routinely monitor the environmental impacts of the different kinds of
river training structures after they have been constructed. The
monitoring that it does conduct is focused more on bendway weirs and
chevrons than on the more prevalent wing dikes. Corps officials told
us this is because routine monitoring of environmental effects is
costly--as much as $320,000 for 4 years of pre-and post-construction
monitoring of a single dike field, and potentially more if contractors
are used. Moreover, they told us that routine monitoring is
unnecessary for wing dikes because the St. Louis District has more
than 100 years of experience with these kinds of river training
structures.
In contrast, FWS and Missouri Department of Conservation officials
told us that additional monitoring is needed for some of these river
training structures--in particular chevrons and bendway weirs--because
not enough is known about how species respond to these structures.
According to officials at the FWS field office that works with the St.
Louis District, in recent years they have opposed the construction of
new bendway weirs in the Middle Mississippi due to a lack of
information regarding the biological and physical impacts of the
structures. These FWS officials, however, acknowledged that the Corps
has shown a willingness to conduct more monitoring of the physical and
biological impacts of river training structures in the future.
According to Corps officials, the Corps has undertaken some
assessments to monitor impacts on species identified in the 2000
biological opinion. For example, the Corps has identified 17 projects
designed to implement the reasonable and prudent alternatives in the
biological opinion for the pallid sturgeon and least tern. These
projects include efforts to quantify young pallid sturgeon groups in
the Middle Mississippi and to monitor the least tern population. The
Corps has also conducted follow-up biological assessments for several
new river training structures to address the proposed structures' site-
specific impacts on these species. FWS noted in its concurrence letter
on one of these follow-up assessments that it is unclear whether the
benefits of proposed river training structure construction in one
river reach (and the consequent reduction in maintenance dredging)
"can fully compensate for the project impacts," but concluded that the
construction met the standards set by the reasonable and prudent
alternatives. FWS officials told us that these kinds of efforts are
challenging because of data limitations, but they believe that more
work needs to be done, particularly related to the longer-term habitat
restoration measures. The Corps is in the process of developing its
pallid sturgeon conservation and restoration plan. As part of this
effort, the Corps is participating in a soon to be published study
with the Missouri Department of Conservation and a university in the
region that analyzed habitat selection patterns of adult pallid
sturgeon and determined that these fish tend to congregate near the
tips of wing dikes.[Footnote 51]
While the Corps has not performed routine environmental monitoring for
its river training structures, it has conducted or contracted for a
number of studies that examine the impacts of the structures on some
types of fish and wildlife habitats. Officials at the St. Louis
District estimate that, between the Corps, its contractors, and other
academics, more than 50 studies have been published on various
environmental effects of training structures in the Mississippi and
other rivers dating back to at least 1982. Several of these studies
indicate that the structures may negatively affect the environment by
converting river habitat into terrestrial habitat and by making the
habitat that remains in the river more homogeneous. However, studies
also show that modifications can be made to the structures to reduce
these negative impacts, as discussed in further detail later in this
report.
The Corps Has Modified Structures over Environmental Concerns but
Disagrees That They Exacerbate Floods:
Two primary concerns have been raised by various researchers with
regard to the impacts of river training structures in the Middle
Mississippi. One set of concerns relates to the degradation of river
habitat, and the Corps has modified some structures in response to
these concerns. The second set of concerns is that the structures are
associated with increased flooding. The Corps disagrees with this
correlation and has taken a number of steps to demonstrate why it
believes that this relationship does not exist. However, despite the
Corps' efforts, professional disagreement remains over the cumulative
impact of river training structures during periods of high flow.
Experts in the fields of river engineering and water resources told us
that physical and numerical modeling could help resolve this issue.
Some Researchers Have Reported That Structures Degrade Habitat, and
the Corps Has Made Modifications in Response:
Some researchers have reported that river training structures can
degrade river habitat for fish and bird species. According to these
researchers, in a natural river there are areas of faster and slower
current, as well as tree snags and other debris on the bed of the
river. There may also be sand bars in the channel, or secondary
channels that flow around islands and rejoin the main channel on the
other side. According to these researchers, in a river managed by wing
dikes, the navigation channel gets deeper as flows are directed into
it. As a result, areas in between wing dikes can fill with sediment,
in some cases replacing aquatic habitat with terrestrial habitat,
while secondary channels can become disconnected from the deeper main
channel during low flows. This transformed habitat can negatively
impact the species that reside there. For example, fish species
encounter water that grows shallower; in some cases, water in a
secondary channel closed off from the main flow becomes low in oxygen
content, further degrading river habitat for fish and other species.
Similarly, as wing dikes change sedimentation patterns in the river,
birds' nests on sandbars that become connected to the riverbank may
become accessible to land-based predators. Moreover, river training
structures can reduce the complexity of the habitat on the bottom of
the channel--for example, a greater concentration of downstream flow
means there are fewer tree limbs and other natural debris on the
channel bed that may house smaller species. According to FWS officials
that work with the St. Louis District, channel degradation resulting
from river training structures alters the natural process of erosion
and deposition that sustains various types of aquatic habitats.
In response to these concerns, the Corps has taken steps to reduce the
impacts of its structures on river habitat. One key improvement is the
notching of existing wing dikes, which allows water to flow through an
individual wing dike or dike field while maintaining each structure's
ability to focus flows into the navigation channel. Benefits of dike
notches include the conversion of sediment-laden areas between dikes
back to aquatic habitat, the ability for fish to pass through the
dikes, and increased oxygen levels in the secondary channels. One
environmental group that we spoke to confirmed the notches' success at
counteracting the loss of aquatic habitat and has partnered with the
Corps to notch wing dikes, as has FWS. See figure 9 for aerial and
close-up views of notched wing dikes in the Mississippi River.
Figure 9: Aerial and Close-up Views of Notched Wing Dikes in the
Mississippi River:
[Refer to PDF for image: 2 photographs]
Source: U.S. Army Corp of Engineers (left); U.S. Fish and Wildlife
Service (right).
Note: Arrows indicate locations of notched wing dikes in the left
photograph.
[End of figure]
In addition, Corps biologists and engineers told us that after many
decades of using wing dikes on the Middle Mississippi, the agency
designed its chevrons specifically to reduce environmental impacts.
According to these officials, chevrons also create more diverse
habitat than wing dikes. As the river plunges over and flows around
the arch-shaped structures, it creates pools behind the arch and in
the scour holes on either end, each of which provides deep water
habitat for fish. When the river is below the chevron's top crest, the
plunge pools become areas of calm water sheltered from upstream flows
where fish can congregate to feed. Corps officials told us that, over
the past 10 years, they have increasingly used these structures for
environmental enhancement in the Middle Mississippi with the
encouragement of FWS. FWS officials confirmed that they generally
prefer chevrons to the St. Louis District's other river training
structures because of their relative habitat benefits. Figure 10 shows
a closer view of one of the three chevrons in the St. Louis harbor.
Figure 10: Close-up View of a Chevron in the St. Louis Harbor:
[Refer to PDF for image: photograph]
Source: GAO.
[End of figure]
Corps officials also noted two additional environmental benefits that
partially offset the disruption to the natural river caused by their
river training structures. First, Corps officials in multiple
districts told us that the introduction of stone into a river largely
devoid of it provides habitat for the macroinvertebrates[Footnote 52]
that serve as the basis for the river's food chain. Second, Corps
officials told us that the structures are less injurious to the
environment than the dredging that would otherwise be necessary to
maintain the required 9-foot channel. Specifically, dredging requires
repeated disturbance of the channel bottom, and the species residing
there, and further disturbance in the area of the river where the
dredged material is deposited. Aggregate data from several Mississippi
River districts show that the Corps has steadily decreased dredging
over the past 50 years as its construction of river training
structures has increased.
Some Researchers Have Reported That Structures Increase Flood Stages,
but the Corps Disagrees:
Some researchers in the Middle Mississippi region have issued reports--
based on statistical analysis of historical river stage and discharge
data--that link the proliferation of river training structures in the
region with higher river levels during periods of high river flow.
These researchers who are critical of the structures' effects report
that by creating impediments in the river to concentrate low flows,
the structures raise the river's height during higher-flow events,
especially floods. For example, one professor at Southern Illinois
University Carbondale--who has partnered with numerous co-authors to
publish a series of journal articles on the subject[Footnote 53]--told
us that there is a general consensus that flood stage magnitudes have
risen over time on the Middle Mississippi. Drawing on historical river
stage and discharge records for St. Louis and elsewhere on the Middle
Mississippi, he has reported that cumulative hydrologic impacts
resulting from the proliferation of river training structures have
caused this change. Through specific gauge analysis, this researcher
found that when flows are below the top level of wing dikes and
concentrated in the channel, river stage decreases because those flows
erode the channel bottom. When flows are above the top level of the
structures but still well within the river's banks, he found no net
effect on river stage; but when river flows approach the top of the
banks and overflow into the floodplain, he found a clear increase in
stage.
According to this researcher, the effect of the structures is reversed
at higher flows because adding dikes to a river channel (1) constricts
the river, reducing its ability to convey floodwaters and (2) makes
the channel rougher and more resistant to flow. His research shows
these effects are compounded when there are multiple dikes that are
each hundreds of feet long, as is common on the Middle Mississippi.
According to this researcher, these effects have been recognized in
other countries as well. He cites the example of the Netherlands,
which has begun lowering dozens of wing dikes along a branch of the
Rhine River and plans to lower hundreds more as part of a nationwide
effort to reduce flood risk in that river's floodplain.
A professor at Washington University in St. Louis, who has studied the
region since the mid-1990s, has also reported that river training
structures can worsen flooding. His research has focused on historical
river stage data for the Middle Mississippi. In a 2001 paper, he
compared this historical record for the prior 140 years to the Corps'
river management practices over that period.[Footnote 54] He found
that flood stages for similar discharges have increased steadily in
the Middle Mississippi since continuous stage-discharge records have
been kept and concluded that wing dikes have contributed to this
increase in river stage. According to his research, this has resulted
in major floods recurring with greater frequency and severity than in
earlier eras. Further, he told us that among several factors that
could have increased river stage--ranging from river training
structures to levees and climate change--the Corps' wing dikes are
responsible for the largest share of this increase.
Other researchers have also published papers documenting increased
river stages due in part to river training structures. Two widely
discussed studies published in 1975 were among the first to advance
this theory.[Footnote 55] We reported on these studies in August 1995
as part of a review of the performance of Mississippi River levees in
the 1993 Midwest flood.[Footnote 56] At that time, we reported that
researchers had used trend analysis to assert a relationship between
long-term increases in flood levels and the Corps' use of levees and
river training structures. However, we found that the value of these
studies was limited by a lack of accurate information about historic
discharge rates and by conflicting results. In the additional studies
that have appeared in scientific journals over the ensuing years
stating that large discharges on the Middle Mississippi are now
associated with higher river stages than in prior eras, the authors
generally conclude that multiple river training structures have a
cumulative impact on flood heights that is greater than any one
structure's effect.
The Corps, however, disagrees with the conclusions of these
researchers, and agency officials told us that the structures are so
deeply submerged during flood events that they are essentially
invisible to the river's flow. They said that they base this
understanding of the structures' cumulative effects on their
professional expertise, their more than 100 years of experience
managing the river, and on past studies conducted by Corps engineers
and independent researchers. Based on this body of knowledge they
agree that wing dikes reduce river stages at low flows as those flows
are deflected into the channel; they also agree that levees are
responsible for some increase in flood stages because they are
designed to hold floodwaters back from portions of the floodplain,
which can force these waters higher. However, they disagree that the
structures have a cumulative impact on the river's stage during high-
flow events. According to Corps officials, as the Middle Mississippi
approaches flood stage and eventually overflows its banks, any
constriction of the river channel is dwarfed by the much wider and
deeper dimensions of the flow. Corps officials told us that the
greatest effect from river training structures occurs just as they are
overtopped, not when they are submerged by 30 feet or more (as is the
case during some St. Louis floods). According to these officials, the
specific gauge analysis results reported by researchers to support
their conclusions are both counterintuitive and contrary to
established models of hydraulic behavior. Corps officials also told us
that although specific gauge analysis is a powerful tool to assess
trends in the river stage-discharge relationship over time, it alone
cannot isolate the effects of river training structures from other
changes in the river and floodplain. A second limitation of specific
gauge analysis is that it cannot account for natural variables like
water temperature, sediment load, and bank vegetation--all of which
can affect river stage. Additionally, they stated that there are not
enough measured discharges for large floods to support a definitive
trend analysis. They further stated that comparisons with rivers in
other countries must take into account important differences, such as
wing dikes that may be taller than those in the Middle Mississippi. We
spoke with a researcher from the Netherlands who confirmed that wing
dikes on a branch of the Rhine are being lowered to reduce flood
heights, as previously discussed, but also confirmed that these dikes
sit relatively higher in the river than those in the Middle
Mississippi.[Footnote 57]
Moreover, according to Corps officials, inaccuracies in historical
flood data have led to the false conclusion that river stages have
grown over time for similar discharges--a position that we also
reported in August 1995.[Footnote 58] River discharge on the Middle
Mississippi has been continuously measured by the USGS since 1933;
before then, the Corps was responsible for such measurements, using
devices and measurement techniques that were generally less accurate
than those later used by USGS. For example, the Corps took its
discharge measurements at St. Louis from boats, often with floating
gauges, whereas USGS measurements were made from bridges with meters
that were used consistently for the rest of the century. In 1935,
1949, and 1952, the Corps tested its earlier methodology against the
USGS methodology and concluded that early Corps discharge measurements
were systematically overstated, especially during floods.
Consequently, the Corps now assesses pre-1933 data separately from
post-1933 data in its own specific gauge analysis. In addition, the
Corps reduced some of its historical discharge measurements to account
for its earlier overstatements. Both of these approaches tend to
flatten the rising trend that has been alleged by other researchers
for river stage increases over time. Researchers who have used
historical discharge data to link river training structures to
increasing stages for similar discharges told us that the Corps'
revised approaches were inappropriate and served to mask a dangerous
flooding trend. In response, the Corps cited a recent USGS study it
commissioned that characterized the accuracy of pre-1933 discharge
measurements as "questionable" and recommended further examination of
the historic record.[Footnote 59]
In addition to its own research, the St. Louis District recently
commissioned four external reviews of the relationship between river
training structures and river stage, three of which have been
completed and generally support the Corps' position.[Footnote 60] The
completed studies were prepared by a USGS hydrologist, a pair of
engineers with several decades of experience on the Mississippi River,
and a statistics professor from Missouri University of Science and
Technology. However, researchers who have raised concerns about the
structures told us that, in their opinion, contractors reporting
directly to the Corps--no matter how well-respected--are not
sufficiently independent to resolve this issue. These researchers
believe that a study conducted by an independent body like the
National Research Council would have greater credibility.
The Corps Has Engaged Critics in Several Ways, but Significant
Professional Disagreement Remains:
The Corps has engaged critics of its river training structures in
several ways in an attempt to resolve these disagreements. For
example, it has invited them to attend the St. Louis District's annual
inspection tour. In addition, it has invited critics to visit district
modeling facilities and meet in person to discuss their research and
relevant data. Some meetings did take place between the Corps' critics
and officials from the St. Louis District, Mississippi Valley
Division, and Corps headquarters. However, neither the Corps nor its
critics reported that these meetings were successful in resolving
their disagreements. Corps officials told us that their efforts to
provide data to the critics of their river training structures were
not reciprocated. The critics who attended these meetings told us that
they believe the Corps listens only to its own staff in its thinking
on this issue, rarely publishing its analyses in peer-reviewed
journals where its assumptions and methodologies could be vetted by
the scientific community. One river expert who is familiar with this
dispute told us that while he is skeptical of work that has been done
linking river training structures to increased flood stages, the Corps
has not done a thorough job of publishing the research it has
completed on the subject at both the district and national levels. St.
Louis District staff agreed that they could do a better job sharing
their analyses with the public. They told us that many studies are
available on the district's website but that they generally have
neither the time nor the resources to prepare articles for journal
publication.
Experts Told Us That Modeling Could Help Determine Structures' Effect
on Flood Stages:
We contacted 16 experts in river engineering and water resources to
see if there was a possible resolution to the disagreement that exists
between the Corps and its critics.[Footnote 61] These experts
generally agreed with the Corps' understanding of the impact of river
training structures on flood stages, but they were less certain about
the nature of the cumulative impact from many such structures
aggregated over many river miles. Specifically, there was general
agreement among the 16 experts that the influence of river training
structures on river stage is diminished during periods of high flow.
However, many of these experts told us that the magnitude of this
effect would depend on specific characteristics of the structures and
the river (similar to the Corps engineering manual's guidance
regarding the influence of channel contraction on flood heights noted
earlier in this report). For example, one expert identified the height
of a structure relative to the overall river depth as the most
important factor, and a second stated that the overall number of
structures and their spacing are key considerations.
Thirteen of the 16 experts told us that the question of river training
structures' cumulative effects on flood stages could be appropriately
addressed by physical or numerical modeling or a combination of the
two. As one expert told us, experimental modeling is much more likely
to be successful than studies trying to unravel stage-discharge
relationships over many decades, since so many physical changes have
occurred in the river during that time. This expert recommended a
numerical model of a large river section with input from a physical
model. Similarly, another expert--who is familiar with the
capabilities of hydraulics laboratories--agreed that a combination of
physical and numerical modeling should be capable of isolating river
training structures' effects on river stage. St. Louis District
officials told us that they have a numerical modeling team, but, as
noted previously, the district's physical models are primarily small-
scale models that are not capable of predicting structures' effect on
river stage. We also spoke with staff from the Corps' Engineer
Research and Development Center, which conducts numerical and large-
scale physical modeling for Corps districts nationwide, to determine
if they thought modeling was a feasible option. The staff, including
two modelers with more than 35 years of experience each, told us that
cumulative effects on river stage are an important issue that, with
sufficient time and resources, could be assessed using a large-scale
model. One modeler emphasized the importance of modeling the effects
of an entire dike field, rather than using the results from a single
structure to predict cumulative effects.
Corps officials acknowledged that their structures' cumulative impact
on river stage in the Middle Mississippi has not been modeled. While
they told us that numerical and physical modeling could potentially be
used to gain additional information on structures' effect on river
stage, they maintain that based on the results of studies conducted by
the agency and others, they are confident of their understanding of
river training structures and do not think that additional modeling
would resolve the issue. Thus, in the absence of specific funding,
they are reluctant to incur the costs of additional modeling.
According to the Corps and other experts we spoke with, such costs
could range from hundreds of thousands to several million dollars, in
part because of the large cost of collecting river data to calibrate a
model--especially if modelers tried to simulate hundreds of river
miles. However, based on our discussions with experts, we believe a
simplified model that focuses on some of the key attributes of the
Middle Mississippi could be useful in resolving disputes over the
river stage effects of a large dike field. The St. Louis District is
currently funding two more limited studies, both at university
laboratories--(1) a numerical model focused on the three chevrons in
the St. Louis harbor and (2) a physical model with up to four
structures built by a district engineer doing graduate research.
According to the Corps, both models are assessing the effect of
multiple river training structures on river stage. Studies such as
these that test the Corps' conclusions regarding the effects of its
structures are worthwhile because, as 1 of the 16 experts told us, "a
good flood defense scheme is one that people believe in; otherwise,
anxiety and fear can measurably diminish a community's quality of
life."
Conclusions:
Congress requires the Corps to maintain a shipping channel in the
Mississippi River that is navigable year-round from northern Minnesota
to the Gulf of Mexico. By maintaining the channel, the Corps has
enabled millions of tons worth of commerce to safely pass through the
Mississippi. Over many decades of meeting this substantial challenge,
the Corps has found that, in comparison to dredging, river training
structures are often a more efficient, effective, and environmentally
friendly way of maintaining the required depth. However, river
training structures also have environmental impacts that the St. Louis
District has not fully addressed. Specifically, in constructing new
river training structures in the Middle Mississippi, the St. Louis
District has not complied with certain federal and state environmental
requirements, in particular with regard to NEPA and CWA. The district
continues to rely primarily on an EIS published 35 years ago and has
not prepared any post-EIS analyses as NEPA requires, even though
significant changes have occurred in the river and in the design of
its structures. Although the Corps has stated that it will prepare
such an analysis in response to our findings, it is unclear when this
will occur, what the scope of it will be, and whether it will be
available for public comment. The St. Louis District also did not
follow the Corps' NEPA regulations calling for its review of new
information that could warrant the preparation of a supplement to its
existing EIS. In addition, the district has inappropriately relied
upon a nationwide permit for maintenance to comply with the
requirements of Section 404 of CWA for the construction of new river
training structures. This new construction does not match the scope of
the maintenance permit, and is inconsistent with Corps regulations and
other districts' practice.
In addition to its navigation and environmental missions, the Corps
also has a mandate to provide flood protection to communities along
the Mississippi River. For those who live near the river, it is
important to have confidence that the Corps' construction of river
training structures for navigational and environmental benefits is not
inadvertently increasing their flood risk. Based on its extensive
experience with these structures and studies it has conducted as well
as those conducted by others, the Corps remains confident in its
conclusion that its river training structures do not exacerbate
floods. However, there remains significant professional disagreement
between the Corps and the critics of its structures. According to
experts, one solution for resolving this disagreement is to conduct
physical or numerical modeling to assess the cumulative effects of
river training structures during periods of high flow.
Recommendations for Executive Action:
We are recommending that the Secretary of Defense direct the Chief of
Engineers and Commanding General of the U.S. Army Corps of Engineers
to take the following five actions:
* To help ensure compliance with NEPA,
- prepare an EA to determine, in accordance with Council on
Environmental Quality and Corps regulations, whether there are
significant new circumstances or information relevant to the Middle
Mississippi navigation project's environmental concerns that have
emerged since publication of the 1976 EIS, and if so, prepare a SEIS
in accordance with NEPA, or if not, prepare a finding of no
significant impact in accordance with NEPA;
- develop and present in the EA an approach to ensure that site-
specific impacts are assessed, as appropriate, for new river training
structures in the Middle Mississippi; and:
- review and revise as needed St. Louis District procedures to ensure
that determinations of whether existing NEPA documents need to be
supplemented are performed in accordance with Corps regulations
implementing NEPA and documented.
* To help ensure compliance with CWA, obtain CWA Section 404 permit-
equivalents and state water quality certifications as required for new
river training structures in the Middle Mississippi.
* To help resolve concerns over river training structures' cumulative
effect on river stages during periods of high flow, conduct physical
or numerical modeling, or some combination thereof, to provide further
insight into the relative magnitude of this effect for flood
conditions on the Middle Mississippi. The Corps should determine and
conduct the appropriate level of review for such modeling under its
Civil Works Review Policy, including consideration of independent
external peer review.
Agency Comments and Our Evaluation:
We provided a draft of this report to the Department of Defense for
review and comment. The department generally concurred with the
recommendations in our report. Specifically, the department agreed
that the Corps should prepare an EA to determine whether there are
significant new circumstances or information relevant to the Middle
Mississippi navigation project's environmental concerns that have
emerged since publication of the St. Louis District's 1976 EIS, and
that the Corps should prepare a subsequent SEIS if the EA identifies
undisclosed and currently unknown significant effects on the human
environment that may require additional analysis and documentation.
The department also agreed that the Corps should develop and present
in the EA an approach to ensure that site-specific impacts are
assessed, as appropriate, for new river training structures in the
Middle Mississippi, and that the Corps should review and revise St.
Louis District procedures to ensure that determinations of whether
existing NEPA documents need to be supplemented are performed in
accordance with Corps regulations implementing NEPA and documented.
While we are encouraged by the department's response, we note that
under NEPA, the Corps must consider relevant external studies in
addition to its own.
With respect to our recommendation that the Corps obtain required CWA
Section 404 permit-equivalents and state water quality certifications
for new river training structures in the Middle Mississippi, the
department agreed that the Corps should perform all CWA assessments
and obtain any certifications required by law and regulation. However,
the department did not agree with our report finding that the Corps
relied on a nationwide permit for maintenance as the mechanism for
ensuring CWA compliance for river training structure construction in
the Middle Mississippi. Instead, the department stated that the Corps
has relied on its 1976 EIS and a CWA Section 404(b)(1) evaluation. The
department's statement is inconsistent with the information provided
to us by Corps officials during the course of our review. According to
some Corps officials, the agency relies on the nationwide permit to
ensure compliance with CWA requirements for construction of river
training structures in the Middle Mississippi. Although the Corps also
provided us its 404(b)(1) evaluation from 1981, it did not provide any
documentation of a permit-equivalent, public notice, or state permits,
all of which would need to accompany the 1981 evaluation in order to
fully meet CWA requirements. Given the conflicting information
provided to us by the department and the Corps, we believe that the
Corps should consider including a description of how it is complying
with CWA requirements when it prepares its forthcoming EA.
Finally, the department partially concurred with our recommendation
that the Corps conduct physical or numerical modeling, or some
combination thereof, to provide further insight into the cumulative
effect of river training structures during flood conditions on the
Middle Mississippi, stating that the implementation of this modeling
would be subject to funding and the results of the Corps' ongoing
monitoring and analysis. The department also stated that the Corps
will consider independent external peer review of the results of its
ongoing studies. While we agree that this may be helpful, it does not
directly address our recommendation that the Corps consider
independent external peer review of any new physical and/or numerical
modeling that it undertakes.
We are sending copies of this report to the Secretary of Defense, the
Chief of Engineers and Commanding General of the U.S. Army Corps of
Engineers, appropriate congressional committees, and other interested
parties. In addition, the report is available at no charge on the GAO
website at [hyperlink, http://www.gao.gov].
If you or your staff have any questions about this report, please
contact me at (202) 512-3841 or mittala@gao.gov. Contact points for
our Offices of Congressional Relations and Public Affairs may be found
on the last page of this report. GAO staff who made key contributions
to this report are listed in appendix III.
Signed by:
Anu K. Mittal:
Director, Natural Resources and Environment:
[End of section]
Appendix I: Objectives, Scope, and Methodology:
[End of section]
In the context of the Middle Mississippi, our objectives were to
examine (1) key requirements and directives that govern the U.S. Army
Corps of Engineers' (Corps) use of river training structures, (2) how
the Corps has addressed key federal and state environmental
requirements in the use of river training structures, (3) the extent
to which the Corps has monitored the hydrologic and environmental
impacts of river training structures, and (4) concerns that
researchers have raised about the hydrologic and environmental impacts
of the Corps' river training structures and how the Corps has
responded to these concerns. Our work focused on the Corps' St. Louis
District and its management of the Middle Mississippi.
To address the first objective, we reviewed relevant provisions in key
federal and state laws, regulations, and guidance that govern the
Corps' use of river training structures. We determined these laws,
regulations, and guidance to be key because they authorize
construction of river training structures and they relate to flooding
and environmental impacts. We traveled to St. Louis to meet with
officials from the Corps' Mississippi Valley Division and St. Louis
District, specifically agency engineers, attorneys, biologists, and
other scientists. We conducted separate interviews with engineering
and environmental staff from each of the five remaining districts in
the Mississippi Valley Division--Memphis, New Orleans, Rock Island,
St. Paul, and Vicksburg--to learn about their requirements for river
training structures. We interviewed state officials involved in
reviewing activities on the Mississippi River, including officials
with the Illinois and Missouri Departments of Natural Resources and
the Missouri Department of Conservation, to identify any requirements
they have related to the Corps' river training structures. We also
reached out to local officials in the city of St. Louis and three St.
Louis-area counties--St. Clair County, Illinois; St. Charles County,
Missouri; and St. Louis County, Missouri--but all four told us they
were not aware of any actions by their jurisdictions to regulate Corps
activities related to river training structures on the Mississippi
River.
To address the second objective, we reviewed Corps documentation for
compliance with the National Environmental Policy Act (NEPA), the
Clean Water Act, the Fish and Wildlife Coordination Act, and the
Endangered Species Act. With respect to NEPA, we reviewed relevant
environmental assessments, environmental impact statements, and a
biological opinion issued by the U.S. Fish and Wildlife Service (FWS)
in 2000. We interviewed officials with the Corps' Office of General
Counsel and obtained in writing the Corps' legal views on how it has
complied with NEPA requirements with respect to its river training
structures built under the navigation authority. We interviewed
officials with the FWS Illinois Sub-Office to discuss Corps actions
related to the Endangered Species Act. We also reviewed Corps
documentation relative to state requirements and interviewed relevant
Corps, state, and local officials discussed previously. We interviewed
officials with several nongovernmental organizations to obtain their
views, including American Rivers, the American Society of Civil
Engineers, the Association of State Floodplain Managers, the Lower
Mississippi River Conservation Committee, the National Wildlife
Federation, and the St. Louis Confluence Riverkeeper.
To address the third objective, we reviewed the Corps' various
assessments of its river training structures. We examined
documentation from selected projects to become familiar with how the
Corps assesses its structures' impacts. We interviewed Corps officials
on the extent to which the Corps conducts pre-and post-construction
hydraulic, hydrologic, and environmental assessments of river training
structures. We reviewed reports on Corps modeling efforts. During our
trip to St. Louis, we visited the St. Louis District's Applied River
Engineering Center to discuss and observe modeling efforts and we
participated in a district-led river tour of the Middle Mississippi
near St. Louis that included observing river training structures. In
our interviews with other districts within the division, we discussed
the extent to which they conduct hydraulic, hydrologic, and
environmental assessments of river training structures. We also
interviewed the previously mentioned nongovernmental organizations for
their views.
To address the fourth objective, we conducted a detailed literature
review of scientific periodicals and government-sponsored research on
the effects of river training structures. Specifically, we used an
iterative process to identify relevant research. We identified search
terms that we refined as we reviewed the literature for terminology
related to this topic. In addition, we reviewed the bibliographies of
literature we had found to identify further studies for review. The
documentary sources cited in our report were reviewed for
methodological strength and reliability and we ultimately determined
them to be sufficiently reliable for our purposes. We believe we have
included the key studies and have qualified our findings, where
appropriate. However, we may not have identified all of the studies
with findings relevant to our objectives. We used this review--along
with interviews of officials from the Corps (as described previously),
FWS, U.S. Geological Survey, and state resource agencies, as well as
other researchers not affiliated with these parties--to compile the
key concerns that have been raised about the structures' hydrologic
and environmental impacts and how the Corps has addressed those
concerns. We interviewed the authors of two of the four recent studies
commissioned by the Corps to evaluate the research that links river
training structures to increased stage. (We did not interview the
authors of the remaining two studies because one was a summary review
of other authors' statistical analysis and the other was a modeling
exercise still underway at the time this report was issued.) We spoke
with officials with the Corps' Engineer Research and Development
Center to discuss physical and numerical modeling. We met with
officials with the National Research Council's Water Sciences and
Technology Board to discuss the Board's role with respect to resolving
professional disagreements over complex scientific issues. We also
interviewed the previously mentioned nongovernmental organizations for
their views.
In addressing the fourth objective, we conducted structured interviews
with 16 experts in the fields of river engineering and water resources
on, among other things, river training structures' potential effects
on river stage; whether such effects can be isolated from other
structures, such as levees, or other hydrologic factors, such as
climate change; and, if so, how this might be done. We used the
"snowball sampling" technique to identify these knowledgeable experts.
Specifically, we identified these experts through recommendations made
during our interview process and by soliciting recommendations from
the following organizations: the National Research Council's Water
Sciences and Technology Board; the American Society of Civil
Engineers, including its American Academy of Water Resource Engineers;
the American Geophysical Union; the Colorado State University Water
Institute; and the World Association of Waterborne Transport
Infrastructure. We sought a balance of experts between those currently
engaged in applied engineering and those currently in academic
positions, and also sought those who were, to the extent possible,
independent from both the Corps and the critics of its river training
structures. Prior to interviewing the 16 experts, we pretested the
structured interview with three subject matter experts and, based on
those results, made adjustments to the structured interview as
necessary. The names of the 16 experts we interviewed are listed
alphabetically in table 1.
Table 1: List of Interviewed Experts:
1. Nani G. Bhowmik, Ph.D., P.E., Life Member and Fellow, ASCE, F.
IWRA, M. AGU, D. WRE, Principal Scientist Emeritus, Illinois State
Water Survey, Prairie Research Institute, University of Illinois.
2. Jeff Bradley, Ph.D., P.E., D.WRE, President, WEST Consultants.
3. Mike Buechter, P.E., Principal Engineer, Metropolitan St. Louis
Sewer District.
4. John Cassidy, Ph.D., P.E., Dist.M.ASCE, NAE, Hon.D.WRE, Independent
Consultant Specializing in Hydraulic and Hydrologic Engineering (also
former Chief Hydraulic Engineer at Bechtel Corporation).
5. Tim Dean, P.E., LEED® AP, Civil Engineer, Intuition & Logic, Inc.
6. David Galat, Ph.D., Adjunct Associate Professor, Department of
Fisheries and Wildlife Sciences, University of Missouri.
7. Marcelo Garcia, Ph.D., Professor, Department of Civil and
Environmental Engineering, and Director, Ven Te Chow Hydrosystems
Laboratory, University of Illinois.
8. Robert R. Holmes, Jr., Ph.D., P.E., D.WRE, Hydrologist, U.S.
Geological Survey.
9. Susan McCrary, P.E., Senior Civil Engineer.
10. Gary Parker, Ph.D., Professor, Department of Civil and
Environmental Engineering and Department of Geology, University of
Illinois.
11. Timothy J. Randle, M.S., P.E., D.WRE., Manager, Sedimentation and
River Hydraulics Group, U.S. Bureau of Reclamation.
12. Bruce Rhoads, Ph.D., Professor and Head of the Geography
Department and Affiliate Professor in the Department of Geology and
the Department of Civil and Environmental Engineering, University of
Illinois.
13. Doug Shields, Jr., Ph.D., P.E., Research Hydraulic Engineer, USDA-
Agricultural Research Service.
14. Colin Thorne, Ph.D., Chair, Physical Geography Department,
Nottingham University (England).
15. Chris Thornton, Ph.D., P.E., Director, Engineering Research
Center, Colorado State University.
16. Chester Watson, Ph.D., P.E., Biedenharn Group, LLC (Emeritus
Professor of Civil Engineering, Colorado State University).
Source: GAO.
[End of table]
We conducted this performance audit from September 2010 through
December 2011 in accordance with generally accepted government
auditing standards. Those standards require that we plan and perform
the audit to obtain sufficient, appropriate evidence to provide a
reasonable basis for our findings and conclusions based on our audit
objectives. We believe that the evidence obtained provides a
reasonable basis for our findings and conclusions based on our audit
objectives.
[End of section]
Appendix II: Comments from the Department of Defense:
Department Of The Army:
Office Of The Assistant Secretary:
Civil Works:
108 Army Pentagon:
Washington, DC 20310-0108:
November 28, 2011:
Ms. Anu Mittal:
Director, Natural Resources and Environment:
U.S. Government Accountability Office:
441 G Street, N.W.
Washington, DC 20548:
Dear Ms. Mittal:
This is the Department of Defense (DoD) response to the GAO Draft
Report, GAO-12-41, "Mississippi River: Actions Are Needed to Help
Resolve Environmental and Flooding Concerns about the Use of River
Training Structures," dated October 27, 2011 (GAO Code 361232).
Thank you for the opportunity to review and comment on the draft report.
Responses to GAO recommendations are enclosed.
Very truly yours,
Signed by:
Jo-Ellen Darcy:
Assistant Secretary of the Army (Civil Works):
Enclosure:
[End of letter]
GAO Draft Report Dated October 27, 2011:
GAO-12-41 (GAO Code 361232):
"Mississippi River: Actions Are Needed To Help Resolve Environmental
And Flooding Concerns About The Use Of River Training Structures"
Department Of Defense Comments To The GAO Recommendations:
Recommendation 1: The GAO recommends that the Secretary of Defense
direct the Chief of Engineers to prepare an environmental assessment
(EA) to determine, in accordance with Council on Environmental Quality
(CEQ) and Corps regulations, whether there are significant new
circumstances or information relevant to the Middle Mississippi River
navigation project's environmental concerns that have emerged since
publication of the 1976 environmental impact statement (EIS), and (1)
if so, prepare a supplemental EIS in accordance with the National
Environmental Policy Act (NEPA), or (2) prepare a finding of no
significant impact in accordance with NEPA. (See page 42/GAO Draft
Report.)
[Note: All recommendations can now be found on pages 48 and 49]
DoD Response: Concur. The Corps will voluntarily perform an additional
EA of river training structures for the Middle Mississippi River
navigation project. The Corps believes that it is in full compliance
with NEPA in regard to these structures. Nonetheless, the Corps is
aware that its position may be subject to question by other entities.
Therefore, consistent with CEQ and Corps regulations, the Corps will
summarize and gather the results of all the studies it has performed
on river training structures and determine whether there are any
substantial or relevant information or data that the Corps has not
considered to date. The Corps has initiated this effort and is
currently preparing a plan for conducting a new EA. The EA will
determine whether there are undisclosed and currently unknown
significant effects on the human environment that may require
additional analysis and documentation. The Corps will make an
objective and formal determination with regard to the necessity of
preparing a supplemental EIS after completion and public review of the
new EA. While these efforts are underway, the Corps will continue to
operate and maintain the project.
Recommendation 2: The GAO recommends that the Secretary of Defense
direct the Chief of Engineers to develop and present in the EA an
approach to ensure that site-specific impacts are assessed, as
appropriate, for new river training structures in the Middle
Mississippi River. (See page 42/GAO Draft Report.)
DoD Response: Concur. As part of the new EA, the Corps will include an
approach that ensures the pre-construction assessment of site-specific
impacts of new river training structures in the Middle Mississippi
River.
Recommendation 3: The GAO recommends that the Secretary of Defense
direct the Chief of Engineers to review and revise as needed District
procedures to ensure that determinations of whether existing NEPA
documents need to be supplemented are performed in accordance with
Corps regulations implementing NEPA and documented. (See page 42/GAO
Draft Report.)
DoD Response: Concur. The Corps will review and revise District
procedures for implementing NEPA, as needed, to ensure that existing
Corps regulations and policies are properly followed and documented.
Recommendation 4: The GAO recommends that the Secretary of the Defense
direct the Chief of Engineers, to help ensure compliance with the
Clean Water Act, to obtain Clean Water Act section 404 permit-
equivalents and state water quality certifications as required for new
river training structures in the Middle Mississippi River. (See page
43/GAO Draft Report.)
DoD Response: Concur. The GAO report indicates that the Corps has
relied on a nationwide permit for Clean Water Act compliance with
respect to construction of river training structures on the Middle
Mississippi River. This is not the case. Instead, the Corps has relied
on the fact that operation and maintenance of the authorized project
is supported by an EIS and a Clean Water Act Section 404(b)(1)
evaluation. Nevertheless, as part of the voluntary commitment to
prepare a new EA, the Corps will perform all Clean Water Act
assessments and obtain any certifications required by law and
regulation.
Recommendation 5: The GAO recommends that the Secretary of the Defense
direct the Chief of Engineers, to help resolve concerns of river
training structures' cumulative effect on river stages during periods
of high flow, conduct physical or numerical modeling, or some
combination thereof, to provide further insight into the relative
magnitude of this effect for flood conditions on the Middle
Mississippi River. The Corps should determine and conduct the
appropriate level of review for such modeling under its Civil Works
Review Policy, including consideration of independent external peer
review. (See page 43/GAO Draft Report.)
DoD Response: Partially concur. The Corps is aware that some
researchers outside the agency do not agree with extensive research
performed by the Corps, other federal agencies and academic
institutions over the past 75 years which has concluded that river
training structures do not have an effect on flood heights. The Corps
and independent experts have reviewed the outside research and do not
believe that there is sufficient evidence to warrant costly and time-
consuming large-scale numerical or physical modeling efforts at this
time. Instead, the Corps will continue its ongoing efforts to monitor
and analyze the effects of the training structures on flood heights,
and undertake physical and/or numerical modeling if those efforts
demonstrate a need to do so and if sufficient funds become available.
The Corps also will consider independent external peer review of the
results of its ongoing studies.
[End of section]
Appendix III: GAO Contact and Staff Acknowledgments:
GAO Contact:
Anu K. Mittal, (202) 512-3841 or mittala@gao.gov:
Staff Acknowledgments:
In addition to the individual listed above, Vondalee R. Hunt
(Assistant Director), Elizabeth Beardsley, David Brown, George
Depaoli, Mark Keenan, Perry Lusk, and Rebecca Shea made significant
contributions to this report. Michael Armes, James Ashley, Cheron
Green, Richard Johnson, Justin Mausel, Sarah M. McGrath, Nathan
Morris, Madhav Panwar, Holly Sasso, Aaron Shiffrin, Ben Shouse, and
Vasiliki Theodoropoulos also made key contributions.
[End of section]
Footnotes:
[1] A floodplain is a lowland area adjacent to inland and coastal
waters that is subject to a 1 percent or greater chance of flooding in
any given year.
[2] For the purposes of this report, hydrologic effects include
impacts associated with the movement and distribution of water,
including flooding.
[3] Pub. L. No. 91-190, 83 Stat. 852 (1970), codified as amended at 42
U.S.C. §§ 4321-4347 (2011). Under NEPA, federal agencies must assess
the effects of major federal actions--those they propose to carry out
or to permit--that significantly affect the environment. NEPA has two
principal purposes: (1) to ensure that an agency carefully considers
detailed information concerning significant environmental impacts and
(2) to ensure that this information will be made available to the
public.
[4] This total includes other types of river training structures. For
example, the St. Louis District uses regularly interspersed mounds of
stone--known as multiple roundpoint structures--to create permeable
dikes for navigation and environmental purposes.
[5] Surface floats are objects that are placed in the water and then
timed to determine how long it takes them to float a known distance.
When properly corrected for wind speed, they give an indication of
flow velocity. Double floats are surface floats attached by twine to a
subsurface float for improved accuracy. Rod floats are wooden poles
with a length sufficient to span the depth of a stream. Current meters
come in various configurations; the most common type uses a set of
rotating cups, which the river's current turns to indicate the flow's
velocity.
[6] In addition to the laws described in this section, other laws
govern certain aspects of the Corps' use of river training structures
in the Middle Mississippi, such as the National Historic Preservation
Act. We selected the laws presented in this report because, based on
interviews and analysis of documents, they were the requirements most
relevant to potential hydrologic and environmental impacts of river
training structures.
[7] Pub. L. No. 69-560, 44 Stat. 1010; Pub. L. No. 71-520, 46 Stat.
918.
[8] WRDAs have been enacted periodically since 1986 to authorize and
modify Corps civil works studies, projects, and programs. See, for
example, Pub. L. No. 99-662, 100 Stat. 4082 (1986); Pub. L. No. 101-
640, 104 Stat. 4604 (1990); Pub. L. No. 110-114, 121 Stat. 1041 (2007).
[9] Pub. L. No. 91-190, 83 Stat. 852 (1970), codified as amended at 42
U.S.C. §§ 4321-4347 (2011).
[10] An EA is a concise public document that provides sufficient
evidence and analysis for determining whether to prepare an
environmental impact statement or a finding of no significant impact,
and is to include brief discussions of the need for the proposal,
alternatives, the environmental impacts of the proposed action and
alternatives, and a listing of agencies and persons consulted. 40
C.F.R. § 1508.9 (2011).
[11] An EIS is a more detailed statement than an EA, and NEPA
implementing regulations specify requirements and procedures--such as
providing the public with an opportunity to comment on the draft
document--applicable to the EIS process that are not mandated for EAs.
An EIS must, among other things, (1) describe the environment that
will be affected, (2) identify alternatives to the proposed action and
identify the agency's preferred alternative, (3) present the
environmental impacts of the proposed action and alternatives, and (4)
identify any adverse environmental impacts that cannot be avoided
should the proposed action be implemented. 42 U.S.C. § 4332(c) (2011),
40 C.F.R. §§ 1501.4, 1508.11 (2011).
[12] GAO, Delaware River Deepening Project: Comprehensive Reanalysis
Corrected Errors, but Several Issues Still Need to Be Addressed,
[hyperlink, http://www.gao.gov/products/GAO-10-420] (Washington, D.C.:
Mar. 31, 2010).
[13] 40 C.F.R. § 1502.9(c) (2011). Courts have explained that
substantial changes to a project warrant supplemental NEPA
documentation. A change is substantial if it presents a "seriously
different picture of the environmental impact." See, for example, Ark.
Wildlife Fed'n v. U.S. Army Corps of Eng'rs, 431 F. 3d 1096 (8th Cir.
2005); Envtl. Def. Fund v. Marsh, 651 F. 2d 983 (5th Cir. 1981).
Similarly, courts have stated that when new information presents a
"seriously different picture of the environmental landscape" another
in-depth look at the environment is necessary. In re Katrina Canal
Breaches Consol. Litig., 647 F. Supp. 2d 644, 723 (E.D. La. 2009). See
also Blue Mountains Biodiversity Project v. U.S. Forest Serv., 229 F.
Supp. 2d 1140 (D. Or. 2002).
[14] Council on Environmental Quality, Forty Most Asked Questions
Concerning CEQ's National Environmental Policy Act Regulations, 46
Fed. Reg. 18,026 (Mar. 23, 1981).
[15] 33 C.F.R. § 230, App. A (3a) (2011) (emphasis added).
Additionally, the Corps' regulations provide that supplemental
documentation will be prepared according to CEQ regulations. 33 C.F.R.
§ 230.13(b) (2011).
[16] According to the Corps' regulations, a SEIS is prepared for
"major changes in the operation and/or maintenance of completed
projects," among other things. 33 C.F.R. § 230.6 (2011).
[17] 33 C.F.R. § 230.7(d) (2011).
[18] See, for example, Recent Past Pres. Network v. Latschar, 701 F.
Supp. 2d 49 (D.D.C. 2010), State of Mississippi v. Marsh, 710 F. Supp.
1488, 1505-06 (S.D. Miss. 1989); Natural Res. Def. Council, Inc. v.
U.S. Nuclear Regulatory Comm'n, 606 F.2d 1261, 1271 (D.C. Cir. 1979).
[19] Federal Water Pollution Control Act, Pub. L. No. 92-500, 86 Stat.
884 (1972), codified as amended at 33 U.S.C. §§ 1251-1387, and
generally referred to as the Clean Water Act.
[20] The Corps' regulatory branch generally administers the permitting
process, and has issued nationwide permits to provide a streamlined
process for certain types of activities that it has found have only
minimal impacts on the aquatic environment.
[21] The guidelines were developed by EPA in consultation with the
Corps. 45 Fed. Reg. 85,344 (Dec. 24, 1980).
[22] Acts of March 10, 1934, ch. 55, 48 Stat. 401, codified as amended
at 16 U.S.C. §§ 661-666c (2011).
[23] The consultation requirement applies to projects or units of
projects whensoever authorized, except that it does not apply to any
project or unit authorized before March 10, 1934, if the construction
of the particular project or unit has been substantially completed,
defined as when 60 percent or more of the estimated construction cost
has been obligated for expenditure.
[24] Pub. L. 93-205, 87 Stat. 884 (1973), codified at 16 U.S.C. §§
1531-1544 (2011).
[25] These monitoring reports may contain information relevant to
reinitiation of formal consultation, among other things. Reinitiation
of formal consultation is required in four instances where
discretionary federal involvement or control over the action has been
retained or is authorized by law: (1) if the amount or extent of
taking specified in the biological opinion is exceeded, (2) if new
information reveals effects of the action that may affect listed
species or critical habitat in a manner or to an extent not previously
considered, (3) if the identified action is subsequently modified in a
manner that causes an effect to the listed species or critical habitat
that was not considered in the biological opinion, or (4) if a new
species is listed or critical habitat designated that may be affected
by the identified action. 50 C.F.R. § 402.16 (2011).
[26] 42 Fed. Reg. 26,951 (May 24, 1977).
[27] 44 C.F.R. § 60.3(d)(3) (2011) ("[In the regulatory floodway,
communities must] prohibit encroachments, including fill, new
construction, substantial improvements, and other development within
the adopted regulatory floodway unless it has been demonstrated
through hydrologic and hydraulic analyses performed in accordance with
standard engineering practice that the proposed encroachment would not
result in any increase in flood levels within the community during the
occurrence of the base flood discharge.")
[28] U.S. Army Corps of Engineers, Implementation of Executive Order
11988 on Flood Plain Management, ER 1165-2-26 (1984).
[29] The base flood is the flood that has a 1 percent chance of
occurrence in any given year (also known as the 100-year flood).
[30] Generally, the federal government is not itself subject to
regulation by state and local government. However, Congress may enact
laws waiving supremacy and subjecting federal agencies to state and
local regulation such as permit requirements. See, for example, Clean
Water Act (33 U.S.C. § 1323(a)), Resource Conservation and Recovery
Act (42 U.S.C. § 6961(a)).
[31] U.S. Army Corps of Engineers, Layout and Design of Shallow-Draft
Waterways, EM 1110-2-1611 (Washington, D.C.: Dec. 31, 1980).
[32] U.S. Army Corps of Engineers, Civil Works Review Policy, Circular
1165-2-209 (Washington, D.C.: Jan. 31, 2010).
[33] U.S. Army Corps of Engineers, Mississippi Valley Division,
Channel Improvement Engineering and Design Activities, Regulation No.
1110-2-8 (Vicksburg, Miss.: Oct. 27, 2005).
[34] U.S. Fish and Wildlife Service, Biological Opinion for the
Operation and Maintenance of the 9-Foot Navigation Channel on the
Upper Mississippi River System (May 2000).
[35] The Applied River Engineering Center was established by the St.
Louis District in 1995 to conduct applied river engineering in an
office laboratory environment. With a staff of about 10, the center
conducts work on behalf of customers such as landowners, private
facility owners, and local municipalities, as well as agency partners
such as FWS, the Missouri Department of Conservation, and the Illinois
Department of Natural Resources. It has also partnered with other
districts within the Corps including the Memphis, Rock Island,
Vicksburg, New Orleans, Galveston, and Kansas City Districts.
[36] U.S. Army Corps of Engineers, St. Louis District, Final
Environmental Statement: Mississippi River between the Ohio and
Missouri Rivers (Regulating Works) (St. Louis, Mo.: April 1976).
[37] "The effects of riverbed degradation on aquatic organisms in the
Middle Mississippi River are not yet fully understood." 1976 EIS at
215a. "The cumulative effect of channelization efforts in the Middle
Mississippi River to date has not been adequately assessed. Perhaps
the most serious adverse impact resulting from the 9-foot channel
project on the Middle Mississippi River is reduction in size and
diversity of the aquatic habitat." Id. at 216.
[38] Corps officials stated that such provisions commonly appeared in
EISs in the 1970s, but that they did not establish any requirements
for further review.
[39] U.S. Fish and Wildlife Service, Biological Opinion for the
Operation and Maintenance of the 9-Foot Navigation Channel on the
Upper Mississippi River System (May 2000); U.S. Army Corps of
Engineers, Final Integrated Feasibility Report and Programmatic
Environmental Impact Statement for the UMR-IWW System Navigation
Feasibility Study (Sept. 24, 2004).
[40] The review did not determine whether a supplement to the EIS was
"warranted," as called for by Corps regulations, but rather whether
one was legally required.
[41] We note that the subject review was an internal document, whereas
more typically, agencies use EAs, revised records of decision, or
formal re-evaluation documents to announce such decisions.
[42] U.S. Army Corps of Engineers, Rock Island District, Operations
and Maintenance, Upper Mississippi River, 9-Foot Navigation Channel,
Final Environmental Impact Statement: Pools 11-22 (1974).
[43] Riprap is defined as loose stone used as a cover for the purpose
of stabilization.
[44] St. Louis District officials also provided us with a Section
404(b)(1) evaluation prepared in 1981 for the construction of dikes in
the Middle Mississippi, but did not provide any associated permit-
equivalent or explain its relevance. According to Mississippi Valley
Division regulations, for compliance with the Clean Water Act, each
district is to review its proposed channel improvement projects
annually to determine if the planned work meets the requirements of
the EPA guidelines, or if updates to the original Section 404
evaluation are required. The regulation indicates that development of
supplemental information or reevaluation and public notice under the
Section 404(b)(1) process may be necessary. See U.S. Army Corps of
Engineers, Channel Improvement Engineering and Design Activities.
[45] According to Corps documents, small-scale synthetic bed models,
called micro-models or hydraulic sediment response models, have been
used since 1994 and replace large-scale coal bed models. With these
small-scale models, engineers are able to replicate the mechanics of
an actual river or stream on an area the size of a normal table top.
[46] For copies of modeling studies, see the Corps' Applied River
Engineering Center's website at [hyperlink,
http://www.mvs.usace.army.mil/arec/reports_hsrmodels.html] (accessed
Sept. 15, 2011).
[47] U.S. Army Corps of Engineers, Sedimentation and Navigation Study
of the Middle Mississippi River in the St. Louis Harbor River Miles
192.0 to 172.0: Hydraulic Micro Model Investigation, Technical Report
M31 (St. Louis, Mo.: 2004).
[48] The Engineer Research and Development Center is a diverse
engineering and scientific research organization that conducts
research and development in support of the Corps' military and civil
works missions, as well as for other federal agencies, state and
municipal authorities, and U.S industry. Headquartered in Vicksburg,
Mississippi, the Center operates seven laboratories in various
locations in the United States, has a staff of about 2,500 federal
employees, and an annual research program exceeding $1 billion.
[49] According to the Corps, because of the interest in potential
river stage impacts due to river training structures, the agency has
contracted with a university to perform research using a numerical
model to evaluate any changes in river stage due to three chevrons
constructed in the St. Louis harbor. This study is also addressed
later in this report.
[50] U.S. Army Corps of Engineers, Waterways Experiment Station, Study
of Effect of Regulation Works on Stream Flow (Vicksburg, Miss.:
February 1964).
[51] James Garvey, et al., Habitat Selection and Movement of Naturally
Occurring Pallid Sturgeon in the Mississippi River (forthcoming).
[52] Macroinvertebrates are animals without backbones that are large
enough to be seen with the naked eye. In the Middle Mississippi, these
species include aquatic earthworms, flies, beetles, crayfishes, and
freshwater mussels, among others.
[53] For example, Nicholas Pinter, Russell Thomas, and Joseph H.
Wlosinski, "Assessing Flood Hazard on Dynamic Rivers," Eos,
Transactions, American Geophysical Union, vol. 82, no. 31 (Washington,
D.C.: July 31, 2001); Jonathan W.F. Remo and Nicholas Pinter, "Retro-
modeling the Middle Mississippi River," Journal of Hydrology, vol. 337
(2007); Nicholas Pinter, Abebe A. Jemberie, Jonathan W. F. Remo,
Reuben A. Heine, and Brian S. Ickes, "Cumulative Impacts of River
Engineering, Mississippi and Lower Missouri Rivers," River Research
and Applications, vol. 26 (2010).
[54] Robert E. Criss and Everett L. Shock, "Flood Enhancement through
Flood Control," Geology, vol. 29, no. 10 (October 2001).
[55] C.B. Belt, Jr., "The 1973 Flood and Man's Constriction of the
Mississippi River," Science, vol. 189, no. 4204 (Aug. 29, 1975);
Michael A. Stevens, Daryl B. Simons, and Stanley A. Schumm, "Man-
Induced Changes of Middle Mississippi River," Journal of the
Waterways, Harbors, and Coastal Engineering Division: Proceedings of
the American Society of Civil Engineers, vol. 101, no. WW-2 (May 1975).
[56] Intense rainfall that deluged the upper Mississippi River basin
in the spring and summer of 1993 caused the largest flood ever
measured at St. Louis. This unprecedented event in nine Midwestern
states generated the highest flood crests ever recorded at 95
measuring stations on the region's rivers, required the evacuations of
tens of thousands of people, and created large-scale disruptions in
transportation, business, and public services. See GAO, Midwest Flood:
Information on the Performance, Effects, and Control of Levees,
[hyperlink, http://www.gao.gov/products/GAO/RCED-95-125] (Washington,
D.C.: Aug. 7, 1995).
[57] According to this researcher, the navigation channel in this
branch of the Rhine has steadily deepened over the years while the
crests of its wing dikes have maintained their original heights.
[58] [hyperlink, http://www.gao.gov/products/GAO/RCED-95-125], 43.
[59] U.S. Geological Survey, Examination of Direct Discharge
Measurement Data and Historic Daily Data for Selected Gages on the
Middle Mississippi River, 1861-2008, Scientific Investigations Report
2009-5232 (Reston, Va.: 2009).
[60] The district expects the fourth study--numerical modeling of
chevron effects by a university hydraulics laboratory--to be completed
by March 2012.
[61] See appendix I for the names of these experts and how they were
selected.
[End of section]
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