1h. Approve storm drainage improvements by city forces for Minnewashta Pkwy CITY OF
CHANHASSEN
690 COULTER DRIVE • P.O. BOX 147 • CHANHASSEN, MINNESOTA 55317
(612) 937 -1900 • FAX (612) 937 -5739
1 MEMORANDUM
I✓ Dui
TO: Don Ashworth, City Manager i '2 _ / o z
" SstOR
FROM: Charles Folch, City Engineer
' _
DATE: December 7, 1992 / 2 ' 4 / 2---
' SUBJ: Approve Storm Drainage Improvement by City Forces
Minnewashta Parkway Improvement Project No. 90 -15
To date, all of the storm sewer installation, as shown on the approved plans, has been
PP P
completed on the Minnewashta Parkway Improvement Project No. 90 -15. However, an issue
' involving the existing waterway between Lake St. Joe and Lake Minnewashta through the
Red Cedar Cove Townhome Association property has been brought to staffs' attention. The
canal stretches for approximately 200 feet from the Minnewashta Parkway culvert apron to
Lake Minnewashta and is located within a drainage easement. In recent years, the flow
through this waterway has been restricted due to the efforts of some eager beavers that
' constructed a blockage inside the old pipe culvert. The installation of the new storm sewer
and culvert crossing pipe should eliminate access for beavers, however, the resulting flow
channel will take on a much wider section and the flow during the spring thaw and after
' significant rain events is expected to be much greater than previously experienced. Even
though the local runoff is being captured and pretreated by a detention pond on the west
side of the roadway, the potential for erosion along the downstream waterway to Lake
1 Minnewashta exists.
Following an investigation of the situation and discussions with the project engineer, staff
has formulated two options to resolve this issue. The first option involves the installation
of a geotextile filter blanket and riprap along the entire channel section from the roadway
outlet to the lake. However, this work is anticipated to be very labor intensive due to the
' hand placement of all the riprap. This is evident from the contractor's cost estimate of
$16,375. The other option would be to enclose the entire waterway in storm sewer pipe
from the roadway outlet to the lake. This would necessitate the installation of
t approximately 200 feet of 42 -inch storm sewer pipe. The contractor has submitted an
estimated cost of $32,875 to construct this option. From a long -term maintenance
standpoint and to avoid creating a potential attractive nuisance (i.e. children playing in the
r
t PRINTED ON RECYCLED PAPER
1
1 Don Ashworth
December 7, 1992
1 Page 2
I channel and throwing rocks, etc.), staffs' preference would be to pipe the waterway segment;
however, at a $33,000 price tag, it would be difficult to recommend this option.
I In an effort to find a way to implement the desired option with economics in mind, staff has
discussed this work with Street Maintenance Superintendent Mike Wegler. Mike informed
me that the next few weeks would be an ideal time to complete the work with minimal
I disturbance to the area due to the frozen ground. In addition, current delays in other
previously scheduled work projects for his department would afford them the opportunity
to begin the work immediately. It is estimated that the work would only take a few days to
I complete. Staff has acquired material and equipment prices and estimates that Option 2
(installing a storm pipe) could be completed by the Street Maintenance Department for
approximately $13,000. This is roughly $20,000 less than the change order estimate received
1 from the contractor.
Staff firmly believes that Option 2 (installing storm sewer pipe from the roadway outlet to
I the lake) is the best long -term solution for this drainage system. Employing available City
forces to complete the work immediately versus in the spring or summer will reduce the
amount of disturbance to the adjacent land and save nearly $20,000 to the overall
1 Minnewashta Parkway Improvement Project. The Red Cedar Cove Townhouse Association
has submitted a letter that they have no objection to the installation of the storm sewer. It
is therefore recommended that City forces be authorized to construct the storm sewer
1 improvement along the waterway between Lake St. Joe and Lake Minnewashta, through the
Red Cedar Cove Townhome Association property, as said improvements are part of the
overall Minnewashta Parkway Improvement Project No. 90 -15.
I ktm
1 Attachments: 1. Location map.
2. Letter from RCCTA dated December 9, 1992.
I 3. Letter from Brown & Cris dated December 2, 1992.
c: Dave Hempel, Sr. Engineering Technician
I Mike Wegler, Street Superintendent
Al Larson, Engelhardt & Associates
Bill Engelhardt, Engelhardt & Associates
1 Louis Guthmueller, RCCTA
1
1
1
LOCATION MAP
I I I
PT HRH S ARK
$ § 1 A § jk
I §
6200 prz/pligs ST. NIP l"fi. 11
'
6300 LAKE I• 11 ' hn- i= f
1�lRG /N /A � E I% ■� A R'. %.•
r r+ m lip i► it: Ot
6400. � t, � � ASTER / � N,
6500 �� Isa. — l /-"� 1 - � %* ,, Y11 ,:. jI . A
ito ii ■■.. - a. otri20.14,i.v. iimi
6700 l �; . ■ter Ell 1
I t gm 6800 A i :Eisikii iil _ � LAKE � �
COUNTR I
OAKS S �'"��'�"..5 !,
ROAD [� M/ N N E w A stir
690D STRAT • - LANE /, A1
•
i /
EXISTING WATERWAY
7000 KINGS ROAD 111114\ ,
< 1 i:::.:" _ .- 4 5)
1
0
7100 0 Q I LAKE T �:��� - UV- \\ ,-
LL x # ' Ill j.lk- \------,___,_ ,----- ,-,
7200 0 ; 1 -
›.. ' )) E ine ■ O C ` /
7300 - 4) o MINWASHTA 'a • /' ' ' a
COURT �r ,
i Ir l
P9 t IIIIII , 0 , , / se
/1400 . ■,\
7500 ■ eV ! ; y s 4 , 1 '=
A liar - 4 k K - 1
Date: December 09. iYY:
To: Charles Folch, Chanhassen City Engineering Dept.
Ai
From: Louis Guthmuelier, President Red Cedar Cove Townhouse
Subject: St. Joe to Minnewashta Waterway
All the members who attended the Red Cesar Cove Townhouse
Association General Meet. i nr on December 08, .992 a =� t C
have the creekbea completely covered over from the road to
where the bridge is now since there is no way t4 net the
picturesque creek,oed back. They did express some concerns
about how the project w i l l 100K when comp l eteo.
' The trees on the eas; bank are a concern. Can they be saved
ana still shape tree area.
Ideaiy, the siopina should go from the creekdec b ack to the
roan so any heavy runoff W1;1 stet back to St.joe.
The new landscapino should blend in with the hilIsiae on the
east aria south sides of the creekbea. Also when the path is
put in there should be no ditch to catch runoff a. i l a l oncz
1 the pathway.
The end of the culvert which will extend past the bridge
will be an eyesore if left as it is by the roan. Could the
' enrlpiece be hidden under a cover of some sort so it would
only be seen from the lakeside. Also one size smaller rock
should be used from the culvert end to the rip rap in lake.
I Al Larson would like to continue the covered pipe all the
way_. to the lake but the members did not think that practical
as there is no way to end it In an eyepleasina manner.
Another problen we have seen is when they moved the dirt up
' next to the treeline, a branch was broken off and some bark
on an oak tree was torn off. I called our tree expert and he
said that dia not bother him but the equipment used to =�•-e
' the ;girt up there may have compacted the soil arouno the
roots of the oaks and aarmaged them. He surd ested that when
the dirt is to oe removes:. caution be used as to try ana
keep off the root area and to not scrape any c: the roots.
' One of the members informea us that the beavers are bads anti
have placed a cam inside the briaoe culvert. In order to
Keen the creek flowing the beaver will have to be removed or
keeping the pipes c: i ear w i l l become a lifetime Pr rj ect .
Basically. we spree to let you cover the creekbea from the
roan to the north side of our bridge but when the project is
completed, we want to have something that is either not
noticable or nice to look at particularly from the decks of
the townhouses facing the lake.
' One more thing, when the trees along the parkway were
removed, any car heading south on the parkway will shine
it's headlights directly into the bedrooms of the townhouses
on the west end of the property. We will need some trees
replanted along the fenceline.
Thank you for your concern on this project. I hope we can
work this out to everyone's satisfaction.
Louis Guthmueller
President, R CTA
470- 02G2 -H
931- 5456 -W
' T00 STO 'ON SN I71d0H -)iiti TE : TZ E6/E02T
b rown Wayne E. Brown
Gregory W. Brown
Michael H. DeVine
Dennis E. Cowan
Geno J. Orfei
cris inc. Guy J. Larson
Ralph H. Larson
December 2, 1992
Mr. Charles D. Folch, P.E.
City of Chanhassen
690 Coulter Drive
P.O. Box 147
Chanhassen, MN. 55317
RE: Minnewashta Parkway Improvement Project No. 90 -15 1
Proposal for up- grading existing ditch between
Minnewashta Parkway & Lake Minnewashta
Our File: Job #877
Dear Mr. Folch:
Pursuant to your request, we quote as follows for the aforegoing work:
Option Number One:
1). Line existing 200' long ditch with filter blanket and rip rap 26' wide.
2). Furnish and install 26 L.F. of 24" C.M.P. along side of existing 24"
steel pipe: LUMP SUM TOTAL: $16,375.00
Option Number Two:
1). Remove existing 42" end section, install 200 L.F. of 42" R.C.P. Class
2 at bottom of existing ditch and re- install salvaged 42" end section.
2). Haul fill over pipe and blend into existing surrounding area.
3). Furnish and install 26 L.F. of 24" C.M.P. along side of existing 24"
steel pipe: LUMP SUM TOTAL: $32,875.00
Thank you for the opportunity to quote you for this work.
Sincerely,
Brown & Cr - Inc.
Ge4 4(401" " i
frfei / 1
Vice Presid ». t
GO /ns
cc: Allen Larson @ Engelhardt & Assoc.
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DEC 0 19:92 1
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East Frontage Road of 1 -35 — 19740 Kenrick Avenue,lakevitle t+Alrlhe_sgt 55044 "1
Phone 612 -469 -2121 • Fax 612 -469 -2463 ; ft
"An Equal Opportunity Employer" +�
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