Draft Army Corps of Engineers Preliminary Restoration

Transcription

Section 1135: Flint River & Swartz Creek
Flint, Michigan
Date:
Division:
District:
DRAFT: 13 April 2004
13 April 2004
Great Lakes & Ohio River
Detroit
PRELIMINARY RESTORATION PLAN
Section 1135, WRDA 1986
Flint River, Flint, Michigan
Project Modification for Improvement of the Environment
1.
PROJECT:
a.
b.
c.
d.
2.
Flint River & Swartz Creek, Genesee County, Flint, Michigan
Project Modification of the Flint River Flood Control Project
for Improvement of the Environment
Congressional Delegation:
Senator Carl Levin (D)
Senator Debbie A. Stabenow (D)
Congressman Dale E. Kildee (D-5th)
Project Proposed for Modification:
Flint River, Michigan Flood Control Channel Improvement
Date Constructed:
For purposes of design, acquisition and construction, the project was
divided into four segments, Sections A, B, C and D. This Preliminary
Restoration Plan focuses primarily on Sections A and B and a small
segment of Section C. Construction of Section A was completed in 1967
and Section B in 1970, totaling a distance of 6,600 feet.
LOCATION:
The project is located along the
Flint River, Flint, Genesee
County, Michigan. The project
boundaries for this report traverse
both sides of the Flint River from
approximately Third Avenue to
the confluence with Swartz Creek.
Flint is approximately 50 miles
northeast of Lansing and 60 miles
northwest of downtown Detroit.
Flint, Michigan
Figure 1
U.S. Army Corps of Engineers
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Preliminary Restoration Plan
Flint, Michigan
Flood Control Project
Approximate Extent
of PRP Study Boundaries
Atwood
Stadium
3rd Avenue
Glenwood
Cemetery
Detroit District
Kettering
University
Delphi
Automotive
Swartz
Creek
Flint River
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Flint, Michigan
3.
PROBLEM DESCRIPTION
The objective or purpose of ecosystem restoration authorities is to restore degraded ecosystem structure,
function, and dynamic processes to a less degraded, more natural condition. This involves consideration
of the ecosystem’s natural integrity, productivity, stability, and biological diversity. Work conducted during
the PRP phase of this project has revealed that the existing Flood Control Project in the study area has
contributed to the degradation of the quality of the environment.
The current ecological conditions of the Flint River are impaired. The area adjacent to the Corps Flood
Control Project is void of nearly all native habitat and lacks plant, animal, and fishery diversity. The
concrete channelization of the river in this area has effectively eliminated nearly all river habitat. The
channel acts as a deterrent to fish migrations, and also presumably presents higher temperatures and low
oxygen levels.
3.
DESCRIPTION OF PROPOSED PROJECT
a. Without Project Condition
Without the project and no modifications to the existing flood control project, the environment in the
immediate area will remain stressed and unnatural in appearance and function. The concrete
channelization of the river in this area will continue to act as a deterrent to fish migration, the
establishment of plant communities, and associated ecosystem and water quality benefits. Without a
project, this segment of the Flint River will also remain relatively inaccessible to the public with a very
poor aesthetic quality.
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Flint, Michigan
4.
b. Major Features
The Flint Flood Control Project was authorized by the Flood Control Act approved July 3, 1958. The
Flint River Flood Control Project extends from the Third Avenue (Sunset Drive) bridge upstream to
the Hamilton Dam on the Flint River, a distance of 11,000 feet, and along the Swartz-Thread Creek
from its confluence with the Flint River upstream to Second Avenue, a distance of 9,800 feet. For
purposes of design, acquisition and construction, the project was divided into four segments, Sections
A, B, C and D. This Preliminary Restoration Plan focuses primarily on Sections A and B and a small
segment of Section C.
Construction of Section A was completed in 1967 and Section B in 1970, totaling a distance of 6,600
feet. The improved channel consists of a concrete-lined trapezoidal section with 2 on 1 side slopes
and intermittent floodwalls. The channel is designed for a 67-year design flood flow of 11,450 cfs.
The objective of the project is to move water through this reach as efficiently as possible to eliminate
flooding. However, the project resulted in the loss of natural river bed and stream bank habitat for
aquatic species.
The City of Flint conducts inspections of the Flint River Flood Control Project on a quarterly basis
throughout the calendar year. The following is excerpted from a July 2003 report.
The U.S. Army Corps of Engineers describes five (5) separate sections of nearly four (4) miles of the
Flint River including portions of the Swartz Creek and Thread Creek. The banks of the project are
described throughout as right and left side. The sides are defined by facing in the downstream
direction. There are specific items identified where maintenance activities are needed throughout the
project. A brief description of the general condition of the project for each of these sections is
presented as follows:
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Flint, Michigan
Section A – Station 0+00 to Station 37+15.5 Flint River
The paved floodwalls are in fair condition. There is minor cracking, spalling and a vast amount of
vegetation growth on the floodwalls. The geotexile silt fence along many areas in the section has collapsed.
On the left side, the top slope at station 20+00 has localized erosion present, causing major slumping and
soil washout. Soil erosion control measures should be taken immediately. At Station 7+00, there is a plastic
pipe coming from the top bank that should be evaluated further.
Section A – Flint River – Left Side
7. Sta. 10+00, there is shoaling and
debris at the bottom of left bank
Section A – Flint River
1. Sta. 0+00, Third Avenue Bridge
Looking Upstream
Section B – Station 37+15.5 to Station 66+02 Flint River
The paved floodwalls are in fair condition. There is spalling, cracking and vegetation growth on both the
left and right sides of the concrete retaining walls. Repairs are needed on some joints, pipes and missing flap
gates. In addition, the area is in overall good condition. Many old bridges have been removed and the area
appears to have been cleaned.
Section B – Flint River – Right Side
21. Sta. 37+15.5, looking beneath Chevrolet Avenue
Bridge.
Section B – Flint River – Right Side
16. Sta. 41+00, vegetation growing in outfall and in
concrete joints.
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Flint, Michigan
Section C-1 – Station 66+02 to Station 77+75 Flint River
Station 0+00 to Station 5+00 Swartz Creek
The concrete floodwall is in fair condition. Chain-link fences near the Atwood Stadium parking lot are in
poor condition, and have been damaged. In addition, there is vegetation growth throughout the section,
which can reduce the flood carrying capacity.
Section C-1 – Flint River
Sta. 76+00, Grand Trunk Western Railroad
Bridge Looking Downstream
Section C-1 – Flint River – Left Side
Sta. 74+00
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Flint, Michigan
Description of Watershed and Upper Flint River
The geographic area of the Flint River watershed encompasses portions of Genesee, Lapeer, Oakland,
Saginaw, Sanilac, Shiawassee, and Tuscola counties in east-central lower Michigan. The watershed
encompasses more than 1,358 square miles and includes 1,639 total river miles and 753 perennial river
miles. The segment of the river that is the subject of this PRP is located within the Flint River-Lower
Main Channel Subwatershed. The subwatershed encompasses 114.53 square miles and includes two
counties, nine townships, three cities, and one village.
The 2001 assessment of the Flint River by the DNR divides the Flint River basin into six river valley
segments. The area that is the subject of this PRP falls within the “Middle Flint River” segment. The
segment extends from the confluence of Swartz Creek, west to the Saginaw County line. This segment is
approximately 26.2 miles and collects Mud, Cole, Brent and Brent Run creeks.
Topography and Soils
Topography and soils are described as gently rolling hills of sandy loam moraines with clay-rich load
between the ridges. There is a rich band of gravel and sand following the Flint River valley that has been
heavily mined. Pre-settlement vegetation consisted of beech-sugar maple forest on the upland moraine
areas and oak-hickory forest, dominated by red and white oak, on the drier moraine ridges. Conifer and
alder swamp forest was found in depressions, but wet meadows were also present along tributaries.
Among the common tree species were maple, white pine, American elm, red ash, and red and white oaks.
Tamarack was also present, especially in very poorly drained soils.
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General Water Quality of Middle Flint River
There are 12 NPDES permits and 18 sites of environmental contamination in the middle Flint segment.
Water quality in the middle and lower Flint are greatly affected by point and nonpoint source pollution
occurring upstream. Biological community impairment is attributed to reduced biological integrity
resulting from habitat loss. Biological integrity for most tributaries is reduced in downstream progression
due to extensive ditching resulting in unstable flow, habitat loss, reduced species richness, and increased
sediment loading. Water Quality Standards are not being attained due to PCB contamination in fish. Water
chemistry parameters indicate elevated nutrient levels and with exceedence in the dissolved oxygen
standard downstream of Flint. Nutrient loading has resulted in abundant plant growth in the mainstem
downstream of Flint. Respiration processes associated with excessive plant growth oftentimes results in
diurnal fluctuations in dissolved oxygen content of the water. Fish contaminant advisories are present for
the entire Flint River downstream of the Hamilton Dam in Flint. Total body contact recreation is not
recommended after any form of precipitation due to elevated bacteria counts. No wildlife contamination
information is available.
Original Fish Communities
Bailey and Smith (1981) identified 112 fish species, 99 native and 13 colonized or introduced, present
in Lake Huron tributaries. A description of the fish community in the Flint River watershed at the
time of European settlement (early 1800s) is not available. However, anecdotal accounts relating to
potamodromous fishes in the Saginaw and Shiawassee rivers infer movement into the Flint River was
probable. Cleland (1966) mentions the following species historically present in the Saginaw Valley:
lake sturgeon, longnose gar, bowfin, longnose sucker, white sucker, silver redhorse, golden redhorse,
shorthead redhorse, yellow bullhead, brown bullhead, channel catfish, northern pike, lake trout, white
bass, rock bass, smallmouth bass, largemouth bass, yellow perch, walleye, and freshwater drum.
Early Native Americans would collect lake sturgeon on the lower Flint River and use their dried flesh
for summer meat and barter (Wood 1916).
Present Fish Communities
Low groundwater inflow, moderate gradient, and a warm-water temperature regime typify this reach. Flow
is unstable due to surface water runoff from surrounding land development. Fish habitat in the upper
reach has been removed and replaced with concrete for flood control. Fish habitat in the lower reach
consists of poolriffle-run sequencing, rock and gravel substrate, and submerged woody structure. This
segment has been identified as a principal spawning location for Saginaw Bay walleye (Leonardi 1997).
Also, the prevailing rock substrate and greater mean depth provide suitable habitat for good smallmouth
bass populations. However, stream bank cover is reduced due to erosion caused by flow fluctuations.
Warmwater cyprinid, centrarchid, and catostomid species dominant the fish community of the Middle
Flint. Leonardi (1997) found gizzard shad, emerald shiner, rock bass, johnny darter, and blackside darter
in moderate abundance. MDNR, Fisheries Division personnel and anglers report white sucker, carp, and
smallmouth bass also in abundance.
Since the early 1980s, a potamodromous walleye run has re-developed in this river reach. Estimates
suggest the magnitude of this run in the realm of 50,000 walleye (Leonardi, unpublished data). Biological
data collected from spawning walleye in the Flint River shows similarities in year class strength and growth
with the Saginaw Bay walleye stock. It is unknown if the spawning run origin is the result of natural
reproduction downstream of Hamilton Dam, from emigration from the upstream impoundments where
reproduction occurs, or a combination of the two. Each of the tributaries in this river reach (Mud, Cole,
Brent, and Brent Run creeks) are characterized by low groundwater inflow, low gradient, and warm-water
temperature regimes. Instream habitat is lacking in each due to erosion from unstable flow and
channelization for drainage. Dominant fish communities found in each creek consisted of cyprinid species
with johnny darter, creek chub, blacknose dace, and bluntnose minnow being most common.
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Aquatic Invertebrates
Aquatic invertebrate sampling in the middle Flint River occurred in 1993 and 1998 at six locations.
Prevailing rock substrate provides good invertebrate habitat. Five locations received acceptable
invertebrate ratings and one location (Vienna Road) was rated excellent (Alexander 1997,
Walterhouse 2001a). Species diversity is high but intolerant species are absent or in low abundance
indicating slight stream impairment. High leech abundance in this segment has been observed during
walleye spawning run assessments. Infestation rates were 27% in 1998 and 15% in 1999. High leech
abundance is indicative of degraded water quality. Urbanization and municipal water discharge affect
water quality in this segment. Tributaries sampled for invertebrates include Brent Run and Mud Creek.
The invertebrate community of Brent Run Creek was rated acceptable and poor in Mud Creek. Diversity
in both tributaries was dominated by tolerant species.
Birds
The most comprehensive survey of Michigan breeding birds, the “Atlas Survey”, was conducted from
1983 to 1988. The survey listed 233 breeding species for Michigan. A total of 146 breeding bird species
were observed in the Flint River watershed. Historically, common loon, osprey, bald eagle, king rail, longeared owl, and passenger pigeon also bred in the watershed but were not observed in the Atlas Survey.
Many non-breeding species also occur. The Genesee Audubon Society lists 116 additional non-breeding
bird species observed in the Flint River watershed.
Endangered watershed species include short-eared owl, barn owl, piping plover, prairie warbler,
loggerhead shrike, and peregrine falcon. Threatened species include common loon, least bittern, bald
eagle, osprey, red-shouldered hawk, merlin, common tern, Caspian tern, long-eared owl, and Henslow’s
sparrow. The passenger pigeon is extinct.
Dams Upstream of Project Area
The Hamilton Dam is a concrete gravity dam located on the Flint River in downtown Flint near U of MFlint near Clifford and Union Streets. The dam was built in the 1920s and is presently used for recreation
and to provide head for a water treatment plant intake. The dam has a height of approximately 22 feet and
a maximum storage capacity of 185 acre-feet at the top of the dam. A ladder design (built in 1978) is
available for fish passage but is ineffective for most warmwater fish species. The dam has a spillway
capacity of 8,900 cfs before overtopping. The routed 100-year flood frequency discharge at the dam is
estimated to be 11,800 cfs. Only two of the six taintor gates are operable and the structure has been
classified as having a high hazard potential. More recent studies have been completed by the MDEQ and
City of Flint but were not available at the time of this report. The City is extremely concerned with the
condition of the Hamilton Dam.
Downstream of the Hamilton Dam structure is a Faber Dam. This inflatable dam was built in 1979 by the
City of Flint for visual and recreational enhancement of the downtown area. It has virtually no storage
capacity. Fish passage and navigability for canoers is impeded. Stakeholders indicated that the bladder dam
at the confluence of the Flint River and Swartz Creek was not functioning properly and causes some
flooding at the Character Inn when in use.
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c. Expected Ecosystem Changes (With Project Condition)
The alternatives for the restoration of the Flint River corridor within the study area call for the
integration of natural processes as a catalytic investment for the reuse and adaptation of the industrial
lands flanking the river. The alternatives are essentially a variation on the same theme with the
distinguishing difference being the breadth and complexity of the integration of the natural processes.
Both alternatives advance the concept of restoring the river corridor in a manner that permits
development of a new community with, at its center, a green spine of connected open spaces.
Common to all the alternatives is the restoration principle that the river will serve as a vehicle for
flood mitigation and stormwater treatment at the same time supporting a series of distinct ecological
communities.
Where possible, the river corridor is proposed to be broadened through the creation of a series of
backwater marshes or oxbows that will serve to create suitable nursery habitat for fish and reptiles as
well as additional floodplain storage for mitigation of flood events within this reach of the river. A
secondary benefit to accrue to these areas will be enhanced water quality of the river and potential
areas for stormwater treatment within the created wetlands and riverine transitional zones.
d. Outputs and Measurements
Implementing an ecosystem restoration project by modifying the existing Corps Flood Control
project has the potential of producing several outputs as detailed below:
Proposed Actions
Outputs
Shoreline Naturalization
Increased habitat diversity
Increased plant diversity
Restoration of native plant communities
Transition between developed land and
Flint River
Improved water quality through sediment
removal and infiltration
Upland Plant Communities/Meadows
Improved terrestrial habitat
Increased habitat diversity
Restoration of native plant communities
Increased infiltration
Marsh/Oxbow Habitat
Diversity of biological communities
Increased infiltration
Water quality improvements
Increased plant and habitat diversity
Improved fisheries habitat
Restore aquatic habitat
e. Significance of Outputs
Multiple entities within the City of Flint and the region are focusing efforts on the revitalization of
urban areas, watershed and water quality issues and the connectivity and access to the natural
resources of the area. The Flint River is a highly notable resource within the City and the region.
Efforts by educational institutions, non-profit organizations, neighborhood groups, the city and
county continue to work toward providing green space and restoring the environment to improve
habitat, water quality and general aesthetics.
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f.
LERRD Issues
It’s anticipated that a significant portion of proposed modifications and improvements would occur
within the Flood Control Project boundaries, although lands would be necessary where space is
available to extend and expand on the naturalization of the shoreline. Although ownership data has
not been made available at the time of this report, it is believed that the vast majority of the property
alongside the existing Flood Control Project is privately held. With the exception of the Atwood
Stadium and Glenwood Cemetery property, the majority of property abutting the Flood Control
Project appears to be owned by Kettering University and General Motors/Delphi. More detailed
LERRD issues and estimates of value will be generated in the next phase of study.
g. Relationship of Proposed Project to Other Activities
There are several projects and stakeholder groups in the area that have plans and projects at varying
stages and levels that would have a direct affect on a modification to the Flood Control Project.
Flint Uptown Reinvestment Strategy
A group of downtown stakeholders (Flint Uptown Reinvestment Corporation) has recently been
working to develop a strategy for the downtown area. The overall goal of the Reinvestment Strategy is
to redefine Flint’s central business district in order to transform it into of the best small-city
downtowns in the United States. The Reinvestment Strategy identifies the specific actions and
projects that can be accomplished individually, while collectively contributing to an implementation
framework for the regeneration of downtown Flint. Specific goals for the plan include:
• A distinct image
• A central marketplace
• A reliable economic base
• A compact, dense building pattern
• A concentration of housing
• An understandable, attractive street system
• A sense of permanence
• A soul
• Community spirit and vision
Concept Goals
• Strengthen Saginaw Street Corridor
• Establish downtown residential neighborhoods
• Improve the City street system for people and cars
• Capitalize on open space resources
• Integrate centers of strength
The plan highlights priorities for the next ten years.
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Downtown Priority Projects (Years 1–3)
•
•
•
•
•
•
•
•
Saginaw Streetscape
Conversion of Uptown Developments
buildings/ Republic Bank Building
Continuing façade improvements
Wayfinding/signage
Arts & Entertainment block redevelopment
URC staffing
Marketing and promotion
Begin 2-way street conversion
Downtown Priority Projects (Years 4-10)
•
•
•
•
•
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City Square Park/Plaza
Relocate Farmer’s Market into
downtown
East Side residential
neighborhood
Riverfront improvements
City Hall park
Flint, Michigan
City of Flint Planning Efforts
Currently, the City of Flint is experiencing a resurgence of planning efforts and citizen involvement.
Plans have either been prepared or are in the process of completion for the downtown area, cultural
center, University of Michigan campus, the Third Avenue Corridor and numerous neighborhood
districts. The City of Flint Planning Commission has realized the need to consolidate ideas and form
an overall vision for the continued growth and success of the entire community.
With this in mind, the Planning Commission has decided to move forward with the development of a
Comprehensive Strategic Plan. They chose this type of master plan because it is comprehensive in its
approach and will assist in the identification of issues and goals related to the City’s future. However,
it also uses strategic planning to help the community focus on specific key issues and actions for
resolution. The master planning process will be managed by a Steering Committee that is appointed
by the Planning Commission. The City is currently (March 2004) in the process of selecting Steering
Committee members. Once that is complete, the Request for Proposals process will begin and
selection of a Planning Consultant will take place.
Flint River Watershed Coalition
The Flint River Watershed Coalition (FRWC) was formed in 1997 and is a collaboration between:
University of Michigan-Flint, Kettering University, Michigan State University, the City of Flint,
Genesee County Government, General Motors, MDEQ, MDNR, concerned citizens, local
businesses, and environmental groups, who feel strongly that the Flint River and its tributaries are a
vital resource needing protection from pollution. The coalition promotes the appropriate use of the
watershed through education, research, technical assistance, and coordination.
The goals of the FWRC are to:
• Provide a forum for the discussion of watershed related issues, encourage analysis and
collaborative problem solving, and act as an information clearinghouse for related resources
and data.
• Educate the public about water quality and ecosystem protection and appropriate use of land
and water resources.
• Promote involvement of citizens, governments, organizations, institutions, and businesses to
protect land and water resources.
• Collect, maintain and develop essential scientific information on area lakes, streams, wetlands,
and ground water.
• Provide technical assistance to citizens, governments, organizations, institutions, and
businesses in order to improve the management of water resources.
• Maintain sufficient human resources and organizational infrastructure.
• Ensure adequate and stable financial resources for the FRWC.
Using grant monies, the FWRC has held conferences discussing watershed issues, funded volunteer
monitoring of benthic macroinvertebrates, conducted river cleanup events, provided trash containers
to commonly frequented areas, and has posted signs identifying the watershed throughout Genesee
and Lapeer counties.
Phase I planning work for a greenway project has been fully funded. It’s anticipated to be a two-year
project to identify and study potential greenways and open space with Genesee, Shiawassee and
Lapeer Counties.
MDNR Fisheries Division
The Mission Statement of MDNR, Fisheries Division is to protect and enhance the public trust in
populations and habitat of fishes and other forms of aquatic life, and promote optimum use of these
resources for the benefit of the people of Michigan and future generations. Fisheries Division seeks
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to: protect and maintain healthy aquatic environments and fish communities and rehabilitate those
now degraded; provide diverse public fishing opportunities to maximize the value to anglers; and
foster and contribute to public and scientific understanding of fish, fishing, and fishery management.
Kettering University
Kettering University is a significant stakeholder in this project. They own and have improved, or have
plans to improve, significant acreage along the north side of the Flood Control Project from
approximately the Third Street Bridge and east of the Chevrolet Avenue Bridge. Representatives from
Kettering attended a stakeholder meeting held in December 2003 and indicated that their long-term
goal is to see green along the river and provide for better access to the natural resource. However, the
University has plans to make substantial investments along the river corridor. The University
expressed concerns about flooding potential if the flood control project is altered.
Kettering University also indicated, by way of subsequent letter, that property that they own along the
north bank of the river, both east and west of Chevrolet Avenue, was formerly used for many years
for heavy industrial manufacturing. Potential environmental impacts to portions of the property is
currently being studied in detail by General Motors Corporation. The preliminary studies suggest that
removal of the existing concrete lining of the riverbed and embankments in this area may have
substantial environmental impacts and would need to be closely coordinated with any remedial actions
taken at the property.
MotorCities-Automobile National Heritage Area
The MotorCities--Automobile National Heritage Area (ANHA) is dedicated to preserving,
interpreting, and promoting Michigan’s rich automotive and labor heritage. It is one of 23
congressionally designated National Heritage Areas in the United States. The Heritage Area
encompasses more than 10,000 square miles in southeastern and central Michigan, including
Dearborn, Detroit, Flint, Jackson, Lansing, Pontiac, Warren and Ypsilanti and features approximately
1,200 auto-related attractions, historic sites and events. The Flint River corridor has a significant and
rich automotive history.
The ANHA brought the potential and interest for the project to the attention of the City of Flint and
the Corps in the hopes of opening the river back up to the people and creating linkages from the
Cultural Center to Kettering University. ANHA is also interested in being able to tell the story of the
extensive automobile heritage within the study area.
Friends of the Flint River Trail
The Flint River Trail is a multi-use trail along one or both sides of the Flint River from downtown,
northeast for approximately 4 miles to the northern edge of Flint near Johnson School off of Branch
Road. The trail is almost continuously asphalt and is suitable for walking, jogging and biking. The
purpose of the Friends organization is to promote greater use of the trail through improved safety,
maintenance and publicity; to improve facilities along the trail; and to extend the trail’s length and
move toward a city/county trail system.
U of M Flint Center for Applied Environmental Research
The Center for Applied Environmental Research (CAER) is a division of University Outreach at the
U of M Flint. The Center was originally established in 1990 as a Groundwater Education in Michigan
(GEM) Center with a grant from the W.K. Kellogg Foundation. The have conducted significant
watershed data collection, analysis and plan development and are currently working on a watershed
planning and monitoring project in the Swartz Creek Watershed.
Flint and Genesee Historical Societies
The Historical Societies have an interest in possible restoration efforts for the Chevrolet Bridge (built
in 1917 and eligible for inclusion in the National Register of Historic Places). The bridge is the oldest
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of the remaining six filled spandrel Luthen arch bridges in Flint. The bridge was also the scene of a
sit-down strike at the plant in the 1930s. The bridge was originally a triple arch concrete reinforced
bridge. The bridge today has two, 75-foot, filled spandrel arches that spring from massive concrete
abutments and a pier with bullnosed cutwaters. The elliptical arches feature tapered, continuous arch
rings that are cast integrally with the concrete spandrel walls. The original third arch span was filled in
as part of the Corps Flood Control Project and one of the original piers was incorporated into the
concrete channel to form an abutment.
Two separate inspections of the bridge have taken place in recent years. An environmental assessment
and programmatic Section 4(f) evaluation conducted for the City of Flint in March 2003 indicated that
the bridge should be replaced due to serious deterioration of the structure and to allow smooth,
unimpeded traffic flow along the entire corridor for all vehicular traffic, including full legal truck loads
and emergency vehicles. At the present time, weight restrictions limit truck usage of the facility.
Rehabilitation was determined cost prohibitive by the city due to chloride contaminated fill,
questionable stability during removal of the fill, deteriorated concrete, and inadequate foundation
capacity. Due to the significant deterioration, the city has increased frequency of Chevrolet Avenue
Bridge inspections to every six months.
A study completed for the Historical Society indicated that the existing bridge is structurally sound
and it can be restored by repairing with minor removal and replacement of deck other areas with the
regular repair methods being used to repair piers and other parts of the bridge. Preliminary estimates
for restoration were approximately $400,000.
The plan that the City of Flint was pursuing was to replace the bridge with design at 90% completion
and funding secured. However, the historical societies have since opposed the City’s plan and are
lobbying for restoration rather than replacement.
Atwood Stadium Authority
The Atwood property was deeded to the city in 1917 and the stadium was dedicated in 1929. In 1999,
the Atwood Stadium Authority was formed to address issues and concerns with the condition and
functionality of the stadium. The Authority has plans for several millions of dollars of improvements
and have begun implementing some including a new scoreboard. At this time, the Authority has not
studied possible links with the river but would be very interested and supportive of the opportunity.
Carriage Town and Flint West Village Neighborhoods
Both neighborhoods are extremely interested in the possibility of naturalizing the river and providing
public access to it. They see the riverfront redevelopment as an essential element in the revitalization
of this area.
Genesee County
The County is supportive of a study of the Flint River and the potential for providing public access
and naturalization of the riverfront for habitat and aesthetic quality. The County also indicated that
there is a County Brownfield Authority and City Brownfield Authority in place that would likely be
interested in future conversations regarding this project. Recent discussions with the County revealed
that they are working with the City and a consultant on a redevelopment plan for the Third Avenue
Corridor which is directly adjacent to and within the Corps PRP study area. The boundaries of their
study extend from 5th Ave. on the north to Court Street on the south and downtown Flint on the
east and Beecher St. on the west. The Flint River bisects the area of their study in half and the river
will be an important element of any long term plans developed for this area.
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h. Alternatives Considered
The alternatives for the restoration of the Flint River corridor within the study area call for the
integration of natural processes as a catalytic investment for the reuse and adaptation of the industrial
lands flanking the river. The alternatives are essentially a variation on the same theme with the
distinguishing difference being the breadth and complexity of the integration of the natural processes.
Both alternatives advance the concept of restoring the river corridor in a manner that permits
development of a new community with, at its center, a green spine of connected open spaces.
Common to all the alternatives is the restoration principle that the river will serve as a vehicle for
flood mitigation and stormwater treatment at the same time supporting a series of distinct ecological
communities. The restoration will permit the City of Flint to build a community around a network of
open spaces and trails that will connect the new development to the central business district and
surrounding historically significant neighborhoods as well as provide for the continued expansion of
the Kettering University campus and the nearby U-M Flint Campus. This environmental restoration
will facilitate a sustainable economic strategy for the reuse of former industrial lands into a new
community that is positioned to meet the market for new homes, business, office, and commercial
development within the core of one of Michigan’s oldest industrial cities.
Alternative A assumes the maximum use of the lands adjacent to the existing river corridor and is
highly dependent on the availability of land for restoration to a more natural riparian ecosystem. The
plan calls for the removal of the concrete channel walls of the flood control project to a point where
the walls meet the channel bottom. The channel bottom is proposed to remain in place for two
purposes, the first being minimizing the cost of demolition and subsequent stabilization/restoration
of the river bottom and the second being the hydraulic benefits of the smooth bottom for flood
conveyance. The river corridor is proposed to be broadened through the creation of a series of
backwater marshes or oxbows that will serve to create suitable nursery habitat for fish and reptiles as
well as additional floodplain storage for mitigation of flood events within this reach of the river. A
secondary benefit to accrue to these areas will be enhanced water quality of the river and potential
areas for stormwater treatment within the created wetlands and riverine transitional zones. Public
access points are proposed for viewing and fishing throughout the river corridor as well as paths and
bike trails connecting to the emerging city and neighborhood non-motorized network.
Alternative B envisions the competition for land for new development as well as constraints related to
contamination will only permit a narrow restored river section. In some cases, engineering controls
for limiting human contact with the soils at the rivers edge are likely to be required. The restoration of
the river will be limited to linear pockets of available land at the rivers edge primarily within the
current area of the channelized flood control project. In addition, where engineering controls are
required to limit human contact with the existing soils, paved terraces with pockets of native plantings
are proposed as a means to limit contact but provide a physical connection to the river for recreation
and enjoyment. Restoration in this alternative is limited to upland areas and transitional zones of the
riverine system and it should be assumed that minimal aquatic habitat is created.
Detroit District
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Flint, Michigan
Typical Slope
2:1 (H:V)
Concrete
Channel Paving
Existing
Concrete
Retaining Wall
Concrete
Channel Paving
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Flint, Michigan
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Flint, Michigan
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Flint, Michigan
i.
Consistency Statement
This analysis and future, more detailed analysis will evaluate and recommend restoration measures
that may be implemented at the project site that do not conflict with the congressionally authorized
Flood Control Project purpose.
It is essential that detailed hydraulic modeling be conducted to determine any potential for increased
flood elevations to ensure the original purpose of the Flood Control Project continues to function
and remain viable. Impacts and the potential for flooding if the project is modified are unknown at
this level of study.
5.
VIEWS OF SPONSOR
The sponsor for this PRP is the City of Flint. In general, they are very interested and supportive of efforts
to naturalize and green the Flint River corridor. They are also supportive of efforts to provide enhanced
public access to the Flint River.
The City has significant concerns related to the existing condition of the Hamilton Dam and its continued
ability to function. This may need to be addressed prior to moving forward with potential alternatives
detailed in this report.
6.
VIEWS OF FEDERAL, STATE AND REGIONAL AGENCIES
Known views of Federal, State, Regional and Local agencies are described in previous sections of this
report.
7.
ENVIRONMENTAL AND REGULATORY COMPLIANCE REQUIREMENTS
The appropriate National Environmental Policy Act documentation will be produced to thoroughly
address any impacts, whether negative or positive, that the project may incur. This document will be
produced during the feasibility phase. Appropriate investigations, coordination and permitting will be
conducted to comply with federal, state and local environmental requirements. In addition to coordinating
with the local stakeholders and abutting property owners, coordination will likely be necessary with the
USFWS, MDEQ, MDNR, City of Flint, and Genesee County.
Several stakeholders have made the project team aware that, due to years of former use for heavy
industrial manufacturing, there are potential environmental concerns along many segments of the Flood
Control Project. Preliminary studies, particularly on property formerly owned by General Motors
Corporation have suggested that removal of the existing concrete lining of the riverbed and embankments
in this area may have substantial environmental impacts and would need to be closely coordinated with
any remedial actions taken at the property.
It’s likely that further geotechnical analysis and environmental studies would need to be completed prior
to advancing the concepts illustrated in this PRP.
8.
COSTS AND BENEFITS
The purpose of the proposed project is to restore the Flint River corridor to a more natural condition and
provide water quality and ecosystem restoration benefits while maintaining the original function of the
Flood Control Project. To determine Federal interest in ecosystem restoration in the proposed project
area, costs and benefits of the alternative plans were estimated and depicted below. A substantial portion
of the benefits of the Flint River Ecosystem Restoration project cannot be monetized; therefore a
benefit/cost ratio to justify the project is not required. However, the non-monetized benefits of this
project are significant and need to be evaluated. Overall benefits will accrue to the aquatic, terrestrial, and
human environments.
Detroit District
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Flint, Michigan
Table 1: Estimated Benefits of Ecosystem Restoration
Habitat Type
Without
Project
With
Project
River (Open Water)
TOTAL*
Alternative A
River
Upland/Meadow
Marsh/Oxbow
TOTAL*
Alternative B
River
Upland/Meadow
TOTAL*
Net Improvement
Area of
Habitat
19.3
Quality of
Habitat (1-10)
2
19.3
8.03
3.54
7
8
8
4
4
4
540.4
257.0
113.3
910.7
19.3
4.8
5
8
3
3
289.5
115.2
404.7
Importance (1-5)
3
Ecological
Output
154.4
154.4
* Totals for each alternative do not equal the same acreage. This is due to the fact that each alternative would require a slightly
larger or smaller project area for implementation.
River
The area of the river was calculated assuming approximately 7,000-feet in length and an average of 120feet wide. The actual width of the river varies throughout the project area. As has been discussed in this
report, without the project, the river in this study area is of fairly poor quality. The construction of the
Flood Control Project degraded the ecosystem of the Flint River. The concrete channelization provides
little to no streamside vegetation and cover, and a general lack of pool and riffle habitat. The
channelization also led to the loss of riparian wetlands and associated riparian vegetation.
The implementation of Alternative A and/or B would improve the quality of the Flint River by providing
increased fisheries habitat as well as riparian plantings and buffer. Benefits to the river would be greater
with the implementation of Alternative A due to the increased water quality benefits, plantings, and
fisheries habitat.
Upland/Meadow
Area calculations for the upland/meadow plantings in Alternative A were calculated by assuming
approximately 7,000-feet in length and an average of 50-feet wide. For Alternative B, the upland/meadow
plantings were assumed to be an average of 30-feet in width due to potential property restrictions. The
actual width and location of these plantings would likely vary along the River. Attempts would be made to
provide areas of habitat with native vegetation as well as create a restored, natural, upland edge to serve as
a transitional zone and buffer along the river. Plantings of native species can also provide for educational
opportunities and substantial aesthetic improvements. The larger the area of upland/meadow habitat that
can be incorporated, the greater the benefit and importance.
Marsh/Oxbow
The wetland/marsh/oxbow proposed in Alternative A would provide enhanced water quality benefits,
and expected significant benefits for fisheries and aquatic habitat. These areas would increase infiltration
and assist in treatment of stormwater runoff from adjacent properties. The oxbow areas would function
by being set slightly above the base flow elevation so that stormwater could be routed to the oxbow
during non-flood event periods and thereby permit the treatment of stormwater in the created wetland of
the oxbow prior to discharge to the River. During flood flow events, the oxbows and expanded shoreline
area would provide flood overflow area thus mitigating the impacts of these flood events to the newly
created development zones and upstream areas.
Detroit District
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Flint, Michigan
Costs
The financial data provided below is a preliminary estimate at this phase to give a general idea of total
project costs. The table contains estimates of construction and operation and maintenance (O&M) costs
for the restoration efforts previously described. Long-term O&M costs for aquatic ecosystem restoration
projects are typically low.
Table 2: Construction Cost Estimates
Construction
Construction Task
Cost
Alternative “A”
Shoreline Restoration
Demolition & Construction (est. 3000 l.f.)
Habitat Creation
Plantings Only (est. $20K/acre)
CONSTRUCTION SUBTOTAL
Contingency (15%)
TOTAL ESTIMATED PROJECT COST
Estimated O&M
Cost*
$21,000,000
$210,000
$231,400
$21,231,400
$3,184,710
$2,300
$212,300
$31,845
$24,416,110
$244,145
Alternative “B”
Shoreline Restoration
Demolition & Construction (est. 1800 l.f.)
Habitat Creation
Plantings Only (est. $20K/acre)
CONSTRUCTION SUBTOTAL
Contingency (15%)
$12,600,000
$126,000
$96,000
$12,696,000
$1,904,400
$1,000
$127,000
$19,000
TOTAL ESTIMATED PROJECT COST
$14,600,400
$146,000
Annual Operation and Maintenance Costs are estimated to be 1% of the Construction cost.
Assumption: Referred to Rouge River Reconnaissance Study for Estimated Costs (similar construction)
Risks
Without the benefit of a complete hydraulic study of the project area, and the availability of limited
environmental/contamination data, potential risks are unknown at this time. Risks could be associated
with modification of the project if the potential for flooding were increased and if it were determined that
contamination levels adjacent to the Flood Control Project were extensive. If flooding and contamination
are determined not to be a significant issue, the risk associated with achieving the project outputs is
anticipated to be low for this project and would decrease significantly after the first growing season. It’s
also anticipated that O&M activities will be more intensive during the first few years while plant materials
mature. During this time, periodic inspections and monitoring should be conducted to ensure that the
restoration efforts are functioning as designed. This may include monitoring to evaluate the hydrology of
the restored systems, inspection of vegetation, species density, species diversity, presence of invasive
species, and water quality. Based on inspection results, adaptive measures may be necessary to modify the
site, structures, replant species, and for control and removal of invasive species. It’s anticipated that annual
O&M costs would also be necessary for general cleaning and maintenance due to the increased use and
enjoyment of the river by the general public.
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Flint, Michigan
9.
IMPLEMENTATION SCHEDULE
A feasibility study schedule of 18 months is anticipated. Below are anticipation milestones for completion
of the study.
Table 3: Anticipated Schedule
Feasibility Study Milestones
Notice of Initiation of Feasibility Phase-Scoping
Field Investigations Complete
Alternative Designs Complete
Prepare DDPR and Draft EA (DEA)
Transmit DDPR and DEA to Division and public
Comment and Response Period
Prepare Final DPR and Final EA
Transmit FDPR and FEA to Division
Plans and Specifications
Execute Project Cooperation Agreement
Advertise Contract
Award Contract
Start Construction
Finish Construction
Start Operation & Maintenance
Date
September 04
September 05
November 05
January 06
February 06
March 06
April 06
May 06
August 06
January 07
February 07
March 07
April 07
April 08
May 08
Anticipated factors that may affect the proposed schedule include the general nature of the project. The
project was originally constructed as a Flood Control Project and functions as such. Concerns remain
regarding the hydraulic affect of modifying the Flood Control Project. There are also concerns of the City
of Flint and other stakeholders as to the condition of the Hamilton Dam, just upstream of the project
area. Resolution of this issue may be the highest priority of the local sponsor. Potential contamination
issues may also affect the project schedule. Stakeholders and property owners have indicated that the
potential of contamination, at varying levels and degrees, exists along portions of the Flood Control
Project.
10.
SUPPLEMENTAL INFORMATION
Since this project is proposing recreational features (pedestrian walkway), the PCA language will deviate
from the model agreement for Section 1135 projects. Consequently, approval of the PCA will have to
come from the Corps of Engineers Headquarters in Washington, DC.
Additional Issues/Data Needs: During the development of this Preliminary Restoration Plan, several
issues were identified that will have to be researched in more detail or additional data collected during the
Feasibility Phase. These include:
• Determine the impacts that the project will have on water levels and flows in the vicinity and
upstream/downstream of the proposed project.
• Water level data
• Flow data
• Historical data
• Geotechnical study for tie-in areas (soil borings, laboratory testing/analysis)
• NEPA compliance
• Soil Samples
• Contamination assessment
• Additional field survey
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Flint, Michigan
11.
FINANCIAL DATA
Section 1135 projects are cost shared at 75% Federal and 25% non-Federal sponsor. Preparation of a
Feasibility Report would be initially funded by the Corps of Engineers, but will be considered part of the
total project cost.
The precise dollar amounts for cash, work in-kind, LERRD’s, and annual OMRRR will be determined in
the Feasibility Phase. No credit will be received for LERRD previously provided as an item of another
Federal Project or shall the value thereof be included in the total project modification costs.
The financial data provided below is a very preliminary estimate at this phase to give a general idea of total
project costs. A more accurate and reliable cost estimate will be developed in the feasibility phase.
Table 4: Ecosystem Restoration Costs
Phase
Total
Section 1135 Project Cost
Alternative A
Alternative B
NonNonFederal
Federal
Total
Federal
Federal
$125,000
$375,000
$500,000
$125,000
$375,000
Feasibility
Plans & Specs
(6%)
$500,000
$1,465,000
$366,250
$1,098,750
$876,000
$219,000
$657,000
Construction
$24,416,110
$6,104,028
$18,312,082
$14,600,400
$3,650,100
$10,950,300
TOTAL
$26,381,110
$6,595,278
$19,785,832
$15,976,400
$3,994,100
$11,982,300
The local sponsor is aware that they will be responsible for all lands, easements, rights-of-ways,
relocations, and disposal areas for the project (LERRDS). In the event that the LERRD cost does not
equal at least 25% of the total project costs, the local sponsor is aware that they must contribute additional
cash to equal 25%.
Federal Allocations to Date:
Detroit District
$10,000
25
Flint, Michigan
12.
REFERENCES
ENGCW-EZ. 11 March 1971. Flood Control on the Saginaw River, Michigan and Tributaries, Flint River
at Flint, Letter Report on Project Beautification.
Flint River Assessment. July 2001. MDNR Fisheries Division Special Report. Joseph Leonardi and
William Gruhn.
Letter from David Doherty, Kettering University. December 19, 2003. Concerns regarding potential
modification of the flood control project.
Flint River Watershed Coalition Website.
Flint River, Michigan Flood Control Channel Improvement Section-A Plans. US Army Corps of
Engineers.1964.
MotorCities-Automobile National Heritage Area: A Self-Guided Booklet of Significant Sites in the History
of Buick Motor Co. and the General Motors Corporation in Flint, Michigan. 2003.
Flint Uptown Reinvestment Master Plan. Sasaki. Powerpoint presentation to Planning Commission 9-2303.
Engineering Study on Structural Stability and Existing Condition of “Chevrolet Avenue Bridge”, City of
Flint, Michigan. Prepared for Genesee County Historical Society. Prepared by Trans Environmental
Engineers. May 2003.
Flint River Basin, Hamilton Dam, Genesee County, Michigan. Inventory No. 060. National Dam Safety
Program Inspection Report. Prepared by MDNR. March 1981.
Environmental Assessment and Programmatic Section 4(f) Evaluation. Chevrolet Avenue Bridge Over the
Flint River. City of Flint, Genesee County, Michigan. March 2003.
City of Flint, Flint River Inspection. July 2003. Wade-Trim.
Initiatives for Uptown: Flint Uptown Reinvestment Strategy. Prepared for Flint Uptown Reinvestment
Corporation. Prepared by Sasaki Associates, Inc and Hamilton, Rabinovitz & Alschuler. July 2003
Detroit District
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Draft Army Corps of Engineers Preliminary Restoration

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