1i. Feasibility study Chan surface water mgmt plan 1 1'
CITY OF
1 CHANHASSEN
I 01: 690 COULTER DRIVE • P.O. BOX 147 • CHANHASSEN, MINNESOTA 55317
(612) 937-1900 • FAX (612) 937-5739
1 MEMORANDUM
I TO: Don Ashworth, City Manager
FROM: Paul Krauss, Planning Director
1 Charles Folch, City Engineer
DATE: July 9, 1992
1 SUBJ:
Authorization to Conduct Feasibility Studies Under the Chanhassen Surface
Water Management Plan
1 From its inception, the City Council has urgedllie..Surface Water Management Program to
produce rapid, cost-effective and visible retunia orilhe city's investment. .While it was
I - recognized that a comprehensive capital imOvement program would be mcluded m the final
plan document, it was believed that the progiam should provide a range of projects in a
shorter time frame.
I ip,
ifie i...,„
We believe much has been accomplishe4to date.
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1 •
Work on a new wetlands ordinance and official maps nearing completion.
• The task force is moving forward on surface:water and water quality programs
1 including nearing adoption of a "Best Management Practices" handbook to.
reduce construction impacts. ..;
1 • All new developments are -required to meet water quality protection standards.
Even city projects are being modified to achieve these goals. :The
I Minnewashta Parkway reconstruction is designed to offer significant
improvements in water quality for Lake Mimiewashta and Lake St. Joe.
I • We have had several direct mailings s and articles in the city newsletter and
Villager outlining the program'and educating residents on sensitive lawn and
property management practices to protect water quality. We also had a booth
I in the Chamber tent and will be conducting lake side demonstrations on Lake
Riley and Lotus Lake on July 11.
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Pt
1 V a 417 . PRINTED ON RECYCLED PAPER
1
Don Ashworth
July 9, 1992
' Page 2
We believe we are now prepared to move forward into a more active phase of the program by
' undertaking relatively quick turn - around, low cost projects that will have a significant
improvement on lake water quality. Given the short time frame, projects on Lotus and Lake
Riley are being suggested since we know the most about them at this time.
' On June 24, 1992, the Surface Water Management Task Force reviewed 3 proposed projects
on Lotus Lake in a memo prepared by Bonestroo Engineering. At the meeting, staff
' suggested a fourth project on Lake Riley. The task force directed staff to review the
proposals and select those which were the most suitable. They recommended that up to
$15,000 of SWMP funds be appropriated to undertake the required feasibility studies.
The projects are described in an attached memo from Bonestroo Engineering. Staff is
recommending that Projects B and C on Lotus Lake be undertaken along with the Lake Riley
' project. We are not recommending Project A on Lotus Lake be undertaken even though it
seems to be an excellent method of improving water quality. We believe that in spite of its
merits, it is a longer range project that is likely to involve significant construction and land
' acquisition costs. We also like the Lake Riley project since we believe most of the expense
can be absorbed by the developer of Lake Riley Hills. Total cost of the 3 recommended
feasibility studies is $15,500.
' Staff wants the City Council to be aware that the SWMP budget can absorb the cost of a few
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of these projects but in the longer term other revenue sources must be considered. You will
recall that our funding level is effectively 50% of what was originally requested. Thus, the
City Council will need to consider raising the quarterly rates at some point. In addition,
larger projects offering area wide improvements are likely to require special assessments.
STAFF RECOMMENDATION
Staff recommends that the city Council authorize spending $15,500 to conduct feasibility
studies under the Surface Water Management Program for Projects B, C and D as outlined in
the July 8, 1992, letter from Bonestroo Engineering.
MANAGER'S COMMENTS:
' The overall objectives of the Surface Water Management Plan remains on schedule, i.e. to
develop and document the plan itself; identify /map /officially protect each of our wetlands;
' identify each of the watersheds, their boundaries, runoff rates, and chemical loadings; prepare
a master storm sewer plan, and identify required expansion and/or new ponding areas to
accommodate the runoff within each of the subdistricts; establish electronic base /topographic
' mapping; etc. Without question, the overall goals and specific projects being developed in
our initial stage of developing a Surface Water Management Program are important if we are
to protect the wetlands on the Ward property, determine where and how big ponding areas
.1
Don Ashworth 1
July 9, 1992
Page 3 1
should be on the Ryan parcel, or to set pipe sizing on the Opus property at Highways 41 & 5.
Unfortunately, all of the work efforts are not project specific. People cannot physically see
improved water quality.
The purpose of the above rambling is to ensure that we recognize that we may be creating
some additional problems through our desire to "see" a project done. I believe it is important
that, as a part of setting "first projects," that we establish initial guidelines that will reduce the
possibility of setting precedents that we cannot live with for larger projects, i.e. Project A is a
good example of a project which could be $100,000- $200,000. When final numbers are
known, we will then have to grapple with the issue of who pays -- Western Hills (primary
drainage area), Lotus Lake drainage area, or the SWMP fund. (I prefer the first option even
though it has the greatest tax impact on me.)
This office would recommend that we move forward with the projects as approved by the
SWMP Committee. However, I would also recommend that, as a part of the approval process,
we state we are doing such as they conform to our guidelines, i.e. the feasibility study is
generally less than $5,000 per project, the estimated construction costs are less than $10,000,
and none of the projects are on lakes which have previously been funded during the study
phase (1992/93).
TTA HMENTS
A C
1. Letter from Bonestroo Engineering dated July 8, 1992. 1
2. Location map.
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I Otto G. Bonestroo, P.E. Howard A. Sanford, PE. Gary F Rylander, P.E. Philip J. Caswell, P.E.
Bonestroo Robert W. Rosene, PE" Keith A. Gordon, P.E. Ismael Martinez, P.E. Mark D. Wallis, P.E.
Joseph C. Anderlik, P.E. Robert R. Pfefferle, P.E. Michael P Rau, P.E. Miles B. Jensen, P.E.
I mon Rosene III , Gravel Marvin L. Sorvala, P.E. Richard W Foster, P.E. Agnes M. Ring, P L. Phillip Gra, P.E.
Richard E. Turner, P.E. David O. Loskota, P.E. Thomas W. Peterson. rson, P.E. Karen L. W avel II P.E.
Glenn Anderl1 & Thomas E
E Noyes, PE. J A. Bourdon, P.E. James d Foster,
am sR. Ma and, P.E. Keith Yapp P.E.
Associates Robert G. Schunicht, P.E. Mark A. Hanson, P.E. Jerry D. Pertzsch, P.E. Shawn D Gustafson, P.E.
I Susan M. Eberlin, C.P.A. Michael T. Rautmann. P.E. Kenneth P Anderson. P.E. Ceolio Olivier, P.E.
*Senior Consultant Ted K. Field, P.E. Mark R. Rolfs. P.E. Charles A. Erickson
Thomas R. Anderson, A.I.A. Mark A. Seip, P.E. Leo M. Pawelsky
Engineers & Architects Donald C. Burgardt. P.E. Gary W Morien, P.E. Harlan M. Olson
Thomas E. Angus, P.E. Daniel J. Edgerton, P.E. James F Engelhardt
1 July 8, 1992
City of Chanhassen
690 Coulter Drive
1 Chanhassen, MN 55317
Attention: Mr. Paul Krauss
I Re: Water Quality Improvements
Lotus Lake Watershed
1 Our File 393
Dear Paul:
I As discussed in our past task force meetings held on May 13 and June 24, we have
developed a scope of study for evaluating possible water quality improvements in Lotus Lake
I and Lake Riley.
As part of the Chanhassen's Water Resources Management Plan currently in progress, we
I have identified four key locations for storm water quality improvements inside the Lotus
Lake and Lake Riley Watersheds (see attached map). This letter presents a scope and
I estimated cost of developing a preliminary analysis of the improvements at each location.
Scope of Services
1 Task 1 - Project Initiation
1 During the project initiation phase, the following specific tasks would be performed:
a. Field inspection of the three sites to determine water quality
1 treatment availability.
b. Analysis of storm water /water quality interaction at each one of the
1 sites.
c. Contact agencies for permits and related issues.
I Task 2 - Identification of Alternatives
1 Feasible alternatives for the reduction of sediments and nutrients into Lotus Lake would be
identified at each site.
2335 West Highway 36 • St. Paul, Minnesota 55113 • 612- 636 -4600
(continued) 1
Task 3 - Modeling of Alternatives
1
The efficiency of each identified alternative would be determined using a water quality
model. The existing water quantity model for Lotus Lake would be used as a basis for
developing this water quality model. The model would consider peak discharges, volumes
of runoff, low flow, and first flush conditions. Concentration reduction for different types
of pollutants going into Lotus Lake would be also modeled.
Task 4 - Environmental Analysis
This feasibility study stud would also include the following tasks:
a. Identification of the existing vegetation at each site, and analysis of
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the impact of the different alternatives on that vegetation.
b. Study of wetland restoration alternatives where needed.
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Task 5 - Report
The findings of the study would be presented in a report on each site outlining the proposed
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storm water quality improvements. The report would present preliminary design data for
the improvements along with cost estimates and implementation priorities. A draft of the
report would be reviewed with the task force and a final report published after receipt of
comments.
ESTIMATED COST
The estimated cost of the three feasibility reports on storm water quality improvements in 1
the Lotus Lake Watershed (Sites A, B, and C) and Lake Riley Watershed (Site D) is
presented in Table 1.
Table 2 shows the feasibility study costs without including Task 4 - Environmental analysis.
The Water Resources Management Plan Task Force allocated a not -to- exceed amount of
$15,000 to carry out some of the proposed feasibility studies. At the June 29 meeting
between Bonestroo and City Staff, it was agreed that Bonestroo will perform the feasibility
studies for Sites B, C, and D. If the three analyses are undertaken at the same time and
included in one report, the total cost of the studies could be reduced to $14,000.
We look forward to working with you on this study.
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Yours very truly,
1
BONESTROO, ROSENE, ANDERLIK & ASSOCIATES, INC.
R 4 JW�.ILJSC 6-G4 4cCA4A414:dtk)
Robert G. Schunicht
[ I
LI TABLE 1
COST ESTIMATE
LABOR HOURS
HOURLY TOTAL
CATEGORY SITE A SITE B SITE C SITE D RATE COST
Principal Engineer 9 5 5 5 $75.00 $1,800
- Project Manager 35 15 15 9 56.00 4,144
Project Engineer 150 66 66 56 50.00 16,900
[ I Drafting 32 16 16 12 41.25 3,135
I J Word Processing 20 12 12 12 1 27.25 1,521
Subtotal $12,000 $5,500 $5,500 $4,500
TOTAL $27,500
TABLE 2
COST ESTIMATE WITHOUT ENVIRONMENTAL ANALYSIS
LABOR HOURS HOURLY TOTAL
L CATEGORY SITE A SITE B SITE C SITE D RATE COST
Principal Engineer 8 5 5 4 $75.00 $1,650 1
Project Manager 24 8 8 6 56.00 2,576
- Project Engineer 106 46 46 43 50.00 12,050
- Drafting 32 16 16 12 41.25
3,135
(- Word Processing 16 8 8 8 27.25 1,089
I ,
Subtotal $9,000 $4,000 $4,000 $3,500
TOTAL $20,500
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