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MEMORANDUM
DATE:
January 11, 2013
TO: Mayor and City Councilmembers
THRU: Darin Atteberry, City Manager-�
Brian Janonis, Utilities Executive Director
Jon Haukaas, Water Engineering & Field S ices Manager,:;7
FROM: Owen Randall, Chief Engineer 6V `
Matt Fater, Special Projects Manager M-r--
RE: West Vine Outfall Stormwater Project
Introduction
The West Vine Outfall Project is a joint project between Fort Collins Utilities and
Latimer County Engineering to alleviate flooding and improve stormwater quality for the West
Vine stormwater basin. The project extends from just north of Vine Drive to the Poudre River
west of Shields consisting of open channel conveyance and water quality detention. This -
memorandum is to update City Council on the project as Staff moves forward with design,
permitting and land acquisitions. Construction of the project is expected to begin in the Fall of
2013.
Background
The West Vine basin, located in northwest Fort Collins, extends from Horsetooth
Reservoir to the Cache la Poudre River and from West Vine Drive to Mulberry Street and
Laporte Avenue. The total area of the basin is approximately 2,350 acres with portions of the
basin in the City of Fort Collins and unincorporated Larimer County. In general, stormwater
drains from west to east along flow paths that are not well defined. Figure 1 identifies the extent
of the basin.
Soldier Creek once flowed from the foothills to the Cache la Poudre River, serving as the
primary flow path for the basin. Agricultural practices over the past century followed by land
development have contributed to removing this historical flow path in many parts of the basin.
In addition, the majority of the land development in the basin occurred prior to the establishment
of storm drainage criteria, resulting in inadequate drainage facilities, repeated flooding and
stormwater pollution.
The basin has experienced documented flooding in 1992, 1994, 1997 and 1999, More
than 250 structures are within the 100-year floodplain (also known as the one percent annual
chance storm). Major transportation routes such as: Shields Street, Vine Drive, Taft Hill Road
and Laporte Avenue are overtopped for the 10-year storm and greater, creating hazardous
conditions. The 100-year floodplain for the West Vine Basin is shown on Figure 2.
West Vine Master Plan
The West Vine Basin Master Drainage Plan, prepared in 1980 and updated in 2003 and
2012, identifies improvements in the basin to alleviate flooding and improve stormwater quality.
The improvements include the construction of detention ponds, water quality ponds, habitat
enhancements, open channels, storm sewers, culverts, and spill structures from the irrigation
canals. The 2003 Master Plan estimated a total cost of improvements at $9.2 million. The West
Vine Outfall Project is the first phase of these improvements serving as the outfall for all future
stormwater improvements in the basin.
City of Fort Collins / Larimer County Cooperation
In 1997, the City of Fort Collins and Larimer County signed an Intergovernmental
Agreement for Stormwater Cooperation. The agreement outlines the City's and the County's
share of the cost of construction, operation, and maintenance of stormwater facilities as specified
in the West Vine Master Drainage Plan. The agreement also establishes a West Vine Stormwater
Utility for the portions of the basin within unincorporated Larimer County. The addendum to the
Intergovernmental Agreement adopted by City Council in July 2012 specifies the City and
County will share in the cost of design for this project. A similar addendum for construction is
planned to be presented to City Council for approval in early 2013 outlining the City and County
cooperation for construction.
Shield Street Improvements
Larimer County is scheduled to begin construction of improvements to Shields Street
from the Arthur Ditch to Willox Street in 2014. Improvements to Shields will include a new
center turn lane, bike lanes, sidewalks and a new bridge over the Poudre River. The West Vine
100-year floodplain overtops Shields Street within the boundaries of the project as shown on
Figure 3. This overtopping of Shields Street must be addressed for the project to meet
stormwater and floodplain criteria and improve safety along this roadway. The West Vine
Outfall project will address flooding of Shields Street up to the 100-year storm. Larimer County
is partnering with the City of Fort Collins to implement the West Vine Outfall project as
identified in the Intergovernmental Agreement.
Alternative Analysis
The project team, consisting of City and County Staff and Anderson Consulting
Engineers, conducted an analysis to determine the feasibility of two channel alignments. The
2
two alignments are shown on Figure 4. Preliminary engineering revealed both alignments are
feasible and of similar cost. The alignments were discussed with impacted property owners
where easement and/or land acquisitions would be required. The Northern Alignment crosses
property owned by Ann Elizabeth Scott and Clinton Arnett. The Eastern Alignment crosses
property owned by Ann Elizabeth Scott, Gregory Doster and Karin Livingston. Numerous
discussions with each land owner indicated land owners along the Northern Alignment are more
willing to consider a land acquisition for the project. Staff is currently pursuing land
negotiations and engineering design for the Northern Alignment.
Public Outreach
A public open house was conducted on August 8, 2012 at Lincoln Jr. High School. Over
1,900 post card invitations were mailed to residents and land owners within the West Vine Basin.
Fifty members of the public attended the open house to meet with staff regarding the project. A
copy of the sign-up sheet is attached.
In addition to the open house, residents can learn more about the project at:
fcgov.com/west-vine-outfall.
Recommended Plan
Staff is recommending the Northern Alignment for the construction of the West Vine
Outfall. Staff intends to construct a project that provides flood mitigation and improved water
quality while creating a natural corridor. The project includes three key features along the
alignment that are described below:
Outfall at the Poudre River - The five-foot vertical drop at the Poudre River will be designed
to safely convey flood flows from the West Vine basin to the River while creating a feature that
is appropriate for the river corridor. The drop will consist of a series of 6"-12" drops constructed
with natural boulders creating a more gradual transition from the channel to the river. The
Poudre River trail will also be rerouted approximately 75 feet to the south with a bridge over
new channel.
Stream Channel — The channel portion of the project will extend from the Poudre River south to
the Arthur Ditch. The channel will be approximately 115 feet wide and 3 feet deep with a low
flow meandering stream in the bottom. Native vegetation will be established along the corridor
after construction is complete.
Water Quality Area — The portion of the project between Vine Drive and the Arthur Ditch will
be a multi -purpose area serving as a water quality area, flood conveyance, wildlife corridor, and
public green space. The area will be excavated and reestablished with native vegetation and
natural contouring. Significant effort will be taken to protect the large existing cottonwoods on
the property.
The total project cost including land acquisition is $2.4 million. At the time of this
memorandum, the City and County jointly have budgeted $2.0 million. The project team will
evaluate options to reduce the total project cost during the design process such that the project
can be constructed within the allowable budget. Otherwise, the team will evaluate options to
phase the project until such funding becomes available.
Land Ownership
Figure 5 shows land ownership associated with the project. The Vine Drive Water
Quality area is within land owned by the City of Fort Collins. The open channel portion of the
project crosses through two private properties owned by Ann Elizabeth Scott and Clinton Arnett.
Staff has worked with these land owners to identify a project alignment that is agreeable to both
parties. Appraisals for the properties have been conducted and negotiations for these
acquisitions are currently underway. The Natural Areas Program and the Stormwater Utility
plan to jointly acquire the land for the channel as well as secure conservation easements for the
remaining portion of the Arnett property. Closing for the acquisitions is expected in early 2013.
Next Stem
As the project moves forward, there are several key tasks that are anticipated for 2013 for
a Fall 2013 construction.
Addendum to the IGA Construction — An addendum to the 1997 Intergovernmental
Agreement for Stormwater Cooperation between the City of Fort Collins and Latimer County
will be needed for construction. It is anticipated this addendum will be ready for Council
consideration in early 2013.
Land Acquisitions — Negotiations are currently underway for the necessary land acquisitions.
Closing for these acquisitions is anticipated in early 2013 contingent on Council approval.
Final Design — Final design will begin in January 2013. Some of the critical tasks associated
with the design included: outfall design to the Poudre, natural contouring and landscaping of the
multi -purpose water quality area, relocations of a 2 1 " sewer and 24" water main, design of the
Arthur Ditch siphon, floodplain and environmental permitting.
West Vine Stormwater Basin
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Figure 1
5
West Vine 100-year Floodplain
Figure 2
6
West Vine 100-year Floodplain along N. Shields St.
Figure 3
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