Conceptual Design Report for the
Fabri Dam Modifications Project
Flint, Michigan
Prepared For:
City of Flint P.O. Box 99
Flint, MI 48501-0099
Flint River Watershed Coalition
432 N. Saginaw St. Suite 1001
Flint MI 48502
Prepared By:
Gary M. Lacy, PE Recreation
Engineering and Planning
485 Arapahoe Ave. Boulder, CO 80302
(303)545-5883
November, 2008
Recreation Engineering and Planning
485 Arapahoe Ave Boulder | CO | 80302
(303) 545-5883
Table of Contents
Introduction......................................................................................................................... 2
Background......................................................................................................................... 2
Economic Benefit................................................................................................................ 6
Project Description............................................................................................................ 12
Anticipated Use................................................................................................................. 16
Accessibility...................................................................................................................... 18
Maintenance...................................................................................................................... 18
Costs.................................................................................................................................. 18
Conclusion ........................................................................................................................ 21
Appendix 1. Conceptual Cost Estimate ........................................................................... 22
Appendix 2. Concept Plan ............................................................................................... 24
Recreation Engineering and Planning
485 Arapahoe Ave Boulder | CO | 80302
(303) 545-5883 1
SECTION 1:
INTRODUCTION
Recreation Engineering and Planning
485 Arapahoe Ave Boulder | CO | 80302
(303) 545-5883 2
Introduction
The Fabri Dam is located downstream from the Hamilton Dam. The structure is an
inflatable dam just west of the Grand Traverse Street Bridge. The original structure was
replaced in 2001 with an Obermeyer Hydro Inc. dam. Recreation Engineering and
Planning was contracted to create a conceptual design to replace this dam with structures
that provide a unique recreational whitewater opportunity in Flint. The purpose of this
project is to modify the current configuration of the dam, facilitate reasonable fish
passage and provide a recreational amenity. Similar dams in cities across the country
have been converted to provide attractive recreational amenities while improving safety
and the riparian environment at the site. The resulting improvements not only provide for
increased safety in the river, but serve as an attraction to residents and visitors who seek
whitewater for recreation, events, and competition. The net effect of such improvements
results in transforming a dangerous hazard into a popular community attraction that
stimulates the local economy.
This report presents a conceptual plan and cost estimate for the construction of
improvements to the Fabri Dam on the Flint River in Flint, Michigan. The conceptual
plan consists of recreational boating improvements as well as related bank and access
improvements. The proposed improvements will create a whitewater paddling amenity
for the local community and a resource for the region. This site contains the physical
characteristics necessary to provide the proposed recreational improvements due to
gradient, flow, and its downtown location with existing associated infrastructure;
including parking, restrooms and access.
Background
Many communities across North America are looking to their river corridors, historically
centers of industry, as the heart of urban renewal plans. Rivers can serve as the catalyst
for economic development, and as the dominant natural feature of communities.
Recreation Engineering and Planning
485 Arapahoe Ave Boulder | CO | 80302
(303) 545-5883 3
Whitewater Parks and Courses are increasingly being explored and built by communities
looking to create a unique attraction and recreational opportunity of national importance.
The term “whitewater park” is analogous to a brand name that has been generally applied
to river access improvement projects all over the US. These projects are located in
diverse communities, with diverse goals. The common thread among all of these projects
is that elements of a public river corridor had become a liability. Whitewater parks
convert river corridors and failing dams from liabilities, to amenities that provide
recreational opportunities and economic stimulus.
Whitewater parks are an emerging trend in North America that provides river related
recreation near a population center. Whitewater parks vary in length from the longest, 1
mile, to the shortest, 1 single feature, but all meet the same goal: attracting diverse users
to a single destination where they can recreate without the logistical issues involved in
more traditional, point A to point B river trips.
These parks can be constructed in all types of rivers and can be designed to achieve a
range of different outcomes. In-stream modification, as seen in the Salida Whitewater
Park, consists of a feature created with carefully placed, native boulders within the
existing channel. The appropriateness of this type of improvement is based on the
availability of flow, the gradient of the stream in the immediate vicinity of the drop
structure, and the geotechnical makeup of the substrata of the river.
In-stream whitewater improvements are popular in appropriate rivers around the western US. This
structure is located in Clear Creek, Golden, Colorado.
Dam modification whitewater parks are also a commonly pursued option, whereby an
existing dam is retrofitted with drop structures to create a whitewater course on the
backside of a dam. Dam modifications, like the Rio Vista Dam shown in the photo
below, serve to eliminate structural stability issues and mitigate existing navigability
hazards while maintaining the existing use of the dam and not negatively impacting the
floodplain. These projects are appropriate when a dam’s function needs to be maintained
but the downstream edge of the dam can be modified for navigation, recreation and fish
passage, or when the crest of a dam can be lowered and the vertical fall of the dam can be
redistributed through a longer reach.
Recreation Engineering and Planning
485 Arapahoe Ave Boulder | CO | 80302
(303) 545-5883 4
This whitewater park in San Marcos, Texas is an example of a dam modification project. The original crest of this dam and its diversion capabilities are maintained while the vertical drop on the back side of the dam is redistributed in a drop/pool sequence.
Diverse communities ranging in population and geographic characteristics are turning to
their rivers as a source of recreation, education, and local pride. Whitewater parks attract
citizens of all ages and socio-economic backgrounds. The operation of these parks across
the country has shown that these types of projects provide a number of benefits including
new recreational opportunities, economic stimulus, enhanced aquatic habitat and
environmental education opportunities.
Recreation Engineering and Planning 485 Arapahoe Ave
Boulder | CO | 80302 (303) 545-5883 5
Economic Benefit
There is substantial, empirical evidence that river access improvements can have
significant, positive, economic benefits, for a local community. Whitewater Parks attract
a desirable demographic of users between the ages of 25-45 with disposable income and
the willingness to travel in pursuit of this specific recreational activity. Golden, Colorado
commissioned an economic impact study in the year 2000 for a whitewater park that was
built in 1996. At the time of the study, the project was shown to have an annual
economic impact of between $1.4million-$2million to the local community. This study
was for a stream which has a usable season of three months. The whitewater park in
Reno, Nevada has a projected economic impact of $18million over the first decade and
contributes to a $9million economic impact of the, annual, three day, Reno River
Festival.
The Truckee River Whitewater Park at Wingfield, Reno Nevada.
Recreation Engineering and Planning
485 Arapahoe Ave Boulder | CO | 80302
(303) 545-5883 6
Recreation Engineering and Planning
485 Arapahoe Ave Boulder | CO | 80302
(303) 545-5883 7
SECTION 2:
SITE
DESCRIPTION
Fabri Dam
Project area
The project area is located at the existing Fabri Dam just downstream of Downtown Flint and the Hamilton Dam (source: www.earth.google.com).
The location for improvements is at the existing Fabri Dam located on the Flint River in
Flint, Michigan. The Fabri Dam is located directly downstream from the University of
Michigan, Downtown Flint and the Hamilton Dam.
The precise amount of hydraulic head is variable however, site inspection has revealed
sufficient vertical fall for recreational improvements.
Recreation Engineering and Planning
485 Arapahoe Ave Boulder | CO | 80302
(303) 545-5883 8
Monthly Mean Streamflow: USGS 04148500 Flint River near Flint, MI from 1932-2007
0
500
1000
1500
2000
Jan
Feb
Mar
Apr
May Ju
n
Jul
Aug
Sep Oct
Nov
Dec
month
cfs
Monthly-mean flows at the proposed project site from 1932 through 2007 Source:
http://waterdata.usgs.gov/nwis/monthly.)
Flows at the site vary from 1500 cubic feet per second (cfs) in the early spring to 250 cfs
in mid-summer to early fall. Extreme flood flows have historically reached above 15,000
cfs in the Flint River, however flows typically peak in the range of 4,000 cfs.
This historic flow data suggests that the project would be useable 12 months a year,
weather permitting. Use of similar projects typically follows the hydrograph. When
flows are higher more experienced users will use the facility; when flows are lower
during the summer months less experienced users and bank-based users will frequent the
site.
Recreation Engineering and Planning
485 Arapahoe Ave Boulder | CO | 80302
(303) 545-5883 9
Peak streamflows at the proposed project site (source: waterdata.usgs.gov, station USGS 04148500
Flint River Near Flint, Michigan).
Recreation Engineering and Planning
485 Arapahoe Ave Boulder | CO | 80302
(303) 545-5883 10
Recreation Engineering and Planning
485 Arapahoe Ave Boulder | CO | 80302
(303) 545-5883 11
SECTION 3:
PROJECT
DESCRIPTION
Project Description
Conceptual Design for Fabri Dam Modifications
A full-page version of this drawing is available in Appendix 2. This plan illustrates the
proposed layout of the suggested improvements at the Fabri Dam. The general layout
provides for five whitewater features located in the main channel of the river. Each
feature would consist of a drop structure with approximately one to two feet of head.
The first three structures would be located upstream of the existing dam and two drop
structures locate at and below the existing dam. The hydraulic fall redistributed through a
longer reach allowing for a more gradual transition along the Flint River. The existing
Obermeyer inflatable dam can be relocated upstream to the first drop structure. This will
allow control of the upstream water surface elevation and preserve the existing flat-water
amenity and aesthetics. A modular whitewater feature can be installed in concert with
Recreation Engineering and Planning
485 Arapahoe Ave Boulder | CO | 80302
(303) 545-5883 12
the relocated Obermeyer Dam to create an adjustable whitewater feature. Adjustability
will facilitate use by a wide cross section of recreational users.
The West Plains Diversion in Pueblo Colorado was modified for fish passage, safety and recreation in
2004.
Typical profile of a dam modification. The hydraulic fall is redistributed through a longer reach.
Recreation Engineering and Planning
485 Arapahoe Ave Boulder | CO | 80302
(303) 545-5883 13
Selective bank access improvements on both banks, including egress and ingress points
as well as seating areas and augmentation of existing trails, should also be included in the
project.
Bank and access improvements can improve safety, connect the public to the river and create
vibrancy in an urban core.
Recreation Engineering and Planning
485 Arapahoe Ave Boulder | CO | 80302
(303) 545-5883 14
Recreation Engineering and Planning
485 Arapahoe Ave Boulder | CO | 80302
(303) 545-5883 15
SECTION 4:
ANTICIPATED
USE
Anticipated Use
Recreation Engineering and Planning
485 Arapahoe Ave Boulder | CO | 80302
(303) 545-5883 16
wer
This project will serve many users and purposes. The
site will be designed to be an attraction to recreational
users. The character of the features created by each of
the drop structures will evolve as the flow rates at the
site increase and decrease throughout the year. At lo
flows the park will provide recreation opportunities for
less experienced river users as well as intermediate and
expert users who come to the site for fitness and practice.
At higher flows of over 1000 cfs the more powerful
whitewater features will create a regional draw for intermediate and expert users while
not preventing the use of the project by inexperienced users.
Paddlers at the Pueblo Whitewater Park
The design can also accommodate upstream fish passage. Future design phases will need
to consider the specific needs of critical local fish species. Generally, the proposed grade
control structures can provide short sections of both higher velocity flow and velocity
shelters to facilitate upstream fish movement.
Whitewater Parks can provide diverse experiences along rivers.
Recreation Engineering and Planning
485 Arapahoe Ave Boulder | CO | 80302
(303) 545-5883 17
Recreation Engineering and Planning
485 Arapahoe Ave Boulder | CO | 80302
(303) 545-5883 18
SECTION 5:
ACCESSABILITY
SECTION 6:
MAINTENANCE
SECTION 7:
COSTS
Accessibility
The site is immediately accessible through the existing
downtown area and trails. Access points would be
constructed both upstream and downstream of the
whitewater features to allow for ingress and egress to
and from the river.
Maintenance
In-stream improvements are virtually maintenance-free
following the first year. Regular inspections should be
scheduled to evaluate any significant erosion during the
first year and every year thereafter. Tree, ice and woody
debris will be passed in the course of normal flows, but
should be removed if suspended during high-use times
as they represent an immediate in-stream hazard.
Maintenance of the existing banks and adjacent park
areas will require typical park maintenance for parking
areas, restrooms, etc.
Costs
See the attached cost estimate. Normally, the bulk of
this cost is in construction of in-channel improvements.
In-stream drops and pools should be constructed, along
with any related paths/ access ways, during low-flow
periods. Reduction in rock costs through donated or
stored rock can have a significant impact on the total
cost of the project.
Recreation Engineering and Planning
485 Arapahoe Ave Boulder | CO | 80302
(303) 545-5883 19
SECTION 8:
FUTURE WORK
Future Work
If the City decides to go forward with this project,
future tasks include but are not necessarily limited to:
• Detail Design
• Flood/Fluid Modeling
• Permit Applications
• Construction and Bid Documents
• Construction Phase Services
These tasks are categorized in Design and Construction
Phase Services, as listed in the attached cost estimate. It is
recommended that the design team open a dialogue with
related planning and government agencies as soon as
possible following the decision to proceed, as it is often
imperative that these stakeholders be included in the
design process.
Boulder Creek
Recreation Engineering and Planning
485 Arapahoe Ave Boulder | CO | 80302
(303) 545-5883 20
SECTION 9:
CONCLUSION
Before and After in the Salida, Colorado Whitewater Park
Recreation Engineering and Planning
485 Arapahoe Ave Boulder | CO | 80302
(303) 545-5883 21
Conclusion
Cost effective, recreational safety improvements can be made at the Fabri Dam site.
These improvements will remove an existing hazard as well as provide a recreational
amenity that will attract recreational users and their families from the region to
downtown Flint. The proposed improvements will preserve the base of the existing dam
while redistributing the head through a longer reach of the Flint River. The hydraulics
formed by the whitewater structures will be user friendly and are not intended to create
hazardous conditions for inexperienced users. Many communities have found that
whitewater parks not only provide solutions to safety issues, but also draw residents as
well as visitors to the river, thus providing an economic driver for the local community.
Similar improvements have had enormous impacts on the quality of life and local
economies of communities throughout the country. REP’s $170,000 whitewater park in
Golden, Colorado has had an estimated 1.7 to 2 million dollar per year impact on the
local economy. Similar estimates have been made for our parks in Breckenridge and Vail.
Another project, a two-channel whitewater park on the Truckee River at Wingfield Island
in Reno, Nevada, has transformed a neglected and denuded section of downtown into a
revitalized urban greenway with walking paths, shaded riverside seating, and picnic areas
all surrounded by world-class whitewater. Just like the cities mentioned above, Flint has
the potential to create a world-class recreational amenity that could benefit the entire
community. For these reasons REP recommends including recreational improvements in
the modification of the Fabri Dam.
Appendix 1. Conceptual Cost Estimate
Recreation Engineering and Planning
485 Arapahoe Ave Boulder | CO | 80302
(303) 545-5883 22
0
00
00
00
00
00
Item # DescriptionEstimated Quantity Unit Unit Price
Item Total Price
1 Mobilization L.S. L.S. $50,000 $50,00
2
Dewater (During low-flow) open Oberemyer gates, construct coffer dams and area pumping.
L.S. L.S. $260,000 $260,000
3
Demo/remove existing Obermeyer Gates-leave concrete abutment walls and concrete base.
L.S. L.S. $160,000 $160,000
4Grouted rock drop structures:
4A (Drop #1)
reconfigured Obermeyer gate, with grouted rock abutments
L.S.
cubic yards grouted rock & reconfiguration of Obermeyer
L.S. $215,000
4B
Drop # 2
1,300 cubic yards grouted rock $180 $234,0
4C Drop # 3 1,300 cubic yards grouted rock $180 $234,0
4DDrop #4-At Dam Face 600 cubic yards
grouted rock $180 $108,0
4E Drop #5 1,000 cubic yards grouted rock $180 $180,0
5Offset Current Deflectors (4) 1,200 cubic yards
grouted rock $180 $216,0
Flint Michigan-Fabri Dam Cost Estimate11/4/2008
Recreation Engineering and Planning
485 Arapahoe Ave Boulder | CO | 80302
(303) 545-5883 23
0
0
6Boulder edge and terracing 3,500 LF $160 $560,000
7Large Random Boulders 40 L.S. $400 $16,00
8 miscellaneous heavy Equipment cost/hour
300 hours $180 $54,00
9
landscape restoration and miscellaneous signage, put-ins, take-outs and trails
L.S. hours $240,000 $240,000
$2,527,000
10 Contingency 25% $631,750
11Design and Permitting 16% $404,320
$3,563,070
$180 $180 $400
Itemized costs:Grouted Rock costs per cubic yardHeavy equipment cost/hourLarge Random Boulders
Subtotal
Total
Recreation Engineering and Planning
485 Arapahoe Ave Boulder | CO | 80302
(303) 545-5883 24
Appendix 2. Concept Plan
Recreation Engineering and Planning
485 Arapahoe Ave Boulder | CO | 80302
(303) 545-5883 25
Recreation Engineering and Planning
485 Arapahoe Ave Boulder | CO | 80302
(303) 545-5883 25
Top Related