1d Bluff Creek ProjectCffYOF
C HASE
7700 ~rl,,et Boulevard
PO Box 147
Chanhassen. MN 55317
Administration
Phone: 9522.27.1100
Fax: 952.227.1110
Building Inspe~ons
Phone: 952.227.1180
Fax: 952.227.1190
Engineering
Phone: 952.227.1160
Fax:. 952.227.1170
Finance
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Phone: 952.227.1120
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Recreation Center
2310 Coulter Boulevard
Phone: 952.227.1400
Fax: 952.227.1404
Plannlnll &
Natural Re~ource~
Phone: 952.227.1130
Fax:'952.227.1110
Public Worim
1591 Park Road
Phone: 952.227.1300
Fax: 952.227.1310
Senior Center
Phone: 952.227.1125
Fax: 952.227.1110
Web Site
;';,;,,v. ci.ch~nhassen.mn.us
FROM:
Todd Geflmrdt, City Manager
Loft Haak, Water Resources Coordinator
DATE: March 25, 2003
SUBJ: Bluff Creek Remeandering Project (File # SWMP 12-Y)
BACKGROUND
In 1996, the City completed the Bluff Creek Watershed Natural Resotacc~
Management Plan, a study on Bluff Creek that assessed its aesthetic and
natural resource values to the City and recommended actions aimed at
preserving the creek ~md its corridor for future generations. One of the actions
recommended to preserve the creek and related natural reso~ was the
restoration of the creek along this stretch (Attachment 1).
The portion of Bluff Creek to be remeandered is located on City property in
the Bluff Creek Preserve south of the railroad tracks and east of Lake Drive
West (Attachment 2). The adjacent land use is primarily residential.
NEED
This portion of the creek was ditched in the past when this area was used for
agricultural purposes. The project will restore the ditched portion of Bluff
Creek to a meandering stream. The restoration will improve aesthe~cs and
decrease erosion within this segment of the stream. The restoration will
provide secondary benefits by reducing flow rates to prevent fin'ther erosion
of downstream portions of the creek, including the highly sensitive bluff areas
south of Pioneer Trail in Chanhassen. The newly constructed channel will
more closely resemble the profile of the more natural portion of the channel
upstream. The location for the new channel was selected based on historic
surveyor's notes describing the meandering creek.
The restoration will include remeandering a new channel, reducing the
channel slope and restoring a floodplain (Attachment 3). The new
meandering channel will be cons~ in an upland area to the east of the
existing ditch. It is thought that Bluff Creek may have existed along this new
aligrm~ent before the creek was ditched. An existing prairie area will be
utilized to restore the floodplain for the new channel. The creek will continue
to flow through the ditched alignment for one growing season so that
vegetation can become established in remeandered channel. This will
The City of Chanha#en, A growing community with clean lakes, quality schools, a charming downtown, thriving businesses, winding trails, and beautiful parks. A grot place to live, work, and play.
Todd Gerhardt
Bluff Creek Remeandering Project
March 26, 2003
Page 2 of 3
improve the stability of the remeandered channel. The ditched alignment will be blocked
and filled during spring/summer 2004 and Bluff Creek will flow through the remeandered
channel.
The complete plans and specifications for this project are available for review at City
Hall.
OTHF~R JURISDICTIONS
The City applied for permits and/or jurisdictional determinations from the following
agencies: United States Army Corps of Engineers, Minnesota Department of Natural
Resources (DNR), Riley-Purgatory-Bluff Creek Watershed District. The permits and/or
determinations are currently pending. The City will work with these agencies to meet all
requirements prior to be~nning work.
FUNDING
The engineer's estimate for the creek remeandering and restoration work is $94,748.00.
The funding for this project will come from the City's Surface Water Management Plan
fund (Fund 720) and from a DNR Conservation Partners Grant. This project falls into the
Surface Water Management portion of the City's Capital Improvement Plan. Costs have
been minimized to the extent possible by obtaining some of the dirt necessary for the
filling of the old channel from the Lake Susan Regional Pond Reconstruction (SWMP
12-xr). In addition, City crews may mobilize in spring/summer 2004 to fill the old
channel. This is being proposed as a bid alternate. City staff will prepare a sealed bid for
that alternate. If the cost for City crews to do the work is less than a second mobiliTation
for a contractor, the work will be done by the City. If not, the 2004 work will be included
in the contractor's scope of work.
PROPOSED TIMELINE
At this time, the project schedule is anticipated to be as follows:
April 14
April 17
April 21
May 5
May 12
May 14
Council approval of Plans and Specs
Submit advertisement to paper
Advertisement published
Open bids
Council awards project
Contractor given notice to proceed
Todd Gerhardt
Bluff Creek Remeandering Project
March 26, 2003
Page 3 of 3
CITY COUNCIL ACTION REQUESTED
Staff recommends that City Council adopt the following motion:
'°l~he Chanhassen City Council approves the plans and specifications for the Bluff Creek
Remeandering Project and authorizes staff to advertise for bids."
ATTACHMENTS
1. Bluff Creek Watershed Natural Resources Management Plan excerpt
2. Location Map: Sheet Gl.01 of Plans for Bluff Creek Restoration
3. Grading Plan: Sheet C5.02 of Plans for Bluff Creek Restoration
A,;~ Lowlc~qd.s
· 2d - Creek/Wetland Restoration
In its natural state, north of the rail road tracks, the creek is wider and
shallower with a symmetrical meander pattern..South of the railroad
tracks and within C~y park property, the creek flows under a road via
a culvert. At this point, the creek has been trenched and
straightened. Considerations should be given to restoring this portion
of the creek, which extends south to the wetland complex.
RestoratJon of the creek would involve moving the creek channel
away from the power line poles and recreating natural meanders.
Slopes into the creek would be reduced and stabilized through
bioengineering. Wrth more gradual slopes, the creek would be better
able to overtop its banks and spill out into the adjacent floodplain.
This would improve hydrologic conditions for wetland vegetation and
provide an excellent site to establish wetland plant species.
The wetland complex on this site is presently dominated by reed
canto7 grass and patches of willow along the north side. A few small
areas of native wetland vegetation are present also. The upper
portion of this site should be restored to lowland hardwood tree and
shrub species. As soil wetness increases, a transition to shrub cart
wetland containing sedges, red oiser dogwood and willow should be
made. As conditions become still wetter, shrub can- should g~ve -,vay
to emergent marsh and finally, emergent marsh should give way to
open water marsh just north of Lyman Boulevard. An outlet control
structure with removable stop logs should be constructed just
upstream from where Bluff Creek passes under Lyman Boulevard.
This wetland complex will provide for water quality and quantdt7
treatment to downstream reaches of Bluff Creek.
Many of the wetland wildlife species listc--cl in Appendix B roi' wetlarJd
comn~unities would recolonize this site following restolation.
Presently, the lack of plant diversity on this site limits wildlife diversity
by limitin§ available food and cover necessary for produc'dve habitat.
By creating a variety of wetland habitats and restoring Bluff Creek to a
natural stream, wildlife values for this site would be improved
significantly.
,
Management efforts should stress protecuon of exisun§ natural
communities and restoration where practical. Restoration of ag~'icu~tural
land back to original Big Woods vegetation will enhance the ecological
integrity of these existing natural areas by creating more interior forest