A. Chanhassen Water TreatmentHoisington Koegler Group Inc.
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To.'
From:
Subject:
Date:
Todd Gerhardt and Paul Oehme
Mark Koegler
Chanhassen Water Treatment
April 7, 2004
This memorandum summarizes water treatment alternatives discussions that occurred at meetings of the
Citizen Advisory Panel (CAP) and City Council from December of 2003 to January of 2004.
In 1998, the City of Chanhassen completed a Comprehensive Plan which stated it might be appropriate for the
City to consider water treatment for iron and manganese in the near future. Also, in 1998 Council adopted a
Water Supply and Distribution Plan which stated treatment of iron and manganese may be necessary in the near
future due to public complaints. Additionally, a water treatment plant has been a part of the City's 5-year Capital
Improvement Plan (CIP) since 2000.
In the spring of 2001, a community survey by Decision Resources indicated a concern among residents about the
water quality in Chanhassen. It should be noted that Chanhassen's water supply at the time did meet all Primary
Drinking Water Standards; however, there were reported problems with odor, poor taste, low pressure and
discoloration of fixtures and clothes. This community response and reported problems indicated to the City
Council that significant improvements were needed.
In June, 2002, the City convened a Citizen Advisory Panel (CAP) to assist the City in choosing a consultant to
complete a Master Water Plan for the community. The Master Plan would provide an overview of the existing
water system, identify locations for future wells, identify distribution system improvements, look at different
water treatment processes, look at potential treatment plant sites, and provide cost estimates for capital
improvements to the system. Following an interview process, the CAP selected Black & Veatch Corporation to
prepare the Master Plan.
City staff and the CAP felt that public involvement was key in determining if water treatment would be needed in
Chanhassen. As such, a city-wide information open house was held in September, 2002. The open house
provided information to residents such as what the Master Plan was, existing problems with the City's water
system, and the different types of water treatment.
The CAP was reconvened in late 2003 to further consider water treatment options as a continuing step in
examining water treatment alternatives following completion of the Water Supply, Treatment, and
Distribution System Master Plan by Black & Veatch in 2003. I acted as a facilitator in the CAP
discussions and technical engineering assistance was provided by Mike Foertsch and Steve Nelson of SEH.
The purpose of the effort was to involve the CAP in the reexamination of water treatment alternatives, with
a focus on treatment methods that might be more financially feasible.
The Citizen Advisory Panel met on December 4, 2003 to renew their role in the water treatment discussion
and to receive an update on the status of Chanhassen's efforts since their involvement in 2003. The group
was provided with a background presentation that included an overview of the Water Supply, Treatment,
and Distribution System Master Plan prepared by Black and Veatch; an update on recent actions by the
City; and an overview of an incremental, multiple plant approach suggested by SEH. SEH was
commissioned by the City to provide a supplement to the much more detailed Black and Veatch plan. The
123 North Third Street, Suite 100, Minneapolis, MN 55401-1659
Ph (612) 338-0800 Fx (612) 338-6838 www.hkgi.com
Direct (612) 252-7120 Email mkoeglerCqOhkgi.com
Memorandum
April 7, 2004
Page 2
purpose of the presentation and discussion was to determine if the CAP felt that the incremental, multiple
plant approach had sufficient merit to warrant further consideration.
Discussion by CAP members focused on benefits to the community from a central plant versus a multiple
plant approach. Panel members stressed that the City should implement water treatment in a manner that
represents the best long-term investment for the City. After hearing more about the SEH approach, the
Panel expressed interest in having a subsequent meeting to review some of the preliminary technical
aspects of the approach. Accordingly, a second meeting was set for December 18, 2003.
The CAP meeting on December lgth featured four agenda items; 1) a recap of the first meeting, a review of
the incremental, multiple treatment plant (SEH) approach, consideration of the pros and cons of central
versus multiple treatment plant options and formulation of a recommendation to the City Council.
The Panel was provided with an overview of the December 4th meeting noting that the discussion on the 4th
was a non-technical overview of the central treatment plant option versus the multiple treatment plant
option. Based on the discussion at that meeting, the group agreed to further consider the technical merits
of the incremental, multiple treatment plant approach suggested by SEH. Accordingly, Steve Nelson and
Mike Foertsch were present to review a memorandum that they prepared in August. Their presentation
outlined a series of system improvements that were designed to meet varying objectives for both the east
and west sides of the community. Key aspects of the SEH approach included:
· East Side of Town (Lotus Lake Well Field) - investigate Toluene, modification of Well No. 4 to
reduce radium, construct a 4.32 MGD pressure filter treatment plant, expand the system of
existing wells, add additional treatment plant capacity, and replace water mains as necessary.
· West Side of Town (Galpin Boulevard Well Field) - Test sequestering agents to control iron and
manganese concentrations, construct an 8 MGD treatment plant and abandon the school well.
· Water from the Galpin Boulevard Well Field is of higher quality than the Lotus Lake Well Field.
Water from the Lotus Lake Well Field exceeds the aesthetic standards for iron by a factor of 3 and
manganese by a factor of 7.
· Consider establishing treatment of 80% of maximum day demand, a standard commonly used by a
number of communities in the Twin Cities Metropolitan Area.
· Place the highest priority on improving water quality in the east side of town since no compliance
issues currently exist in the west side, high pressure area. Treatment is needed in the Lotus Lake
Well Field to meet upcoming requirements, as soon as 2008.
· Implement treatment in the west side of town in the future as needed based on capacity constraints
and potential future compliance issues.
After an overview of the memorandum prepared by SEH, the Panel examined the pros and cons of a central
treatment plant option versus multiple treatment plants. The following lists the pros and cons of various
treatment alternatives as well as the "no treatment" option:
Memorandum
April 7, 2004
Page 3
Central Treatment Plant
Pros Cons
)` Staff addresses operational needs
at one location
)` Chemical storage at one location
)-Requires securing of only one
location
)`Extensive disruption of community for connected collection
system.
)` Less ability to phase in improvements
)` Higher cost
)`More complex approach, therefore,
schedule
more risk to cost and
Requires "working against the grain", reversing the current flow
of water in some areas
Incremental. Multiple Treatment Plants
Pros Cons
Lower cost
Enhanced ability to phase improvements
More flexibility for performing periodic
maintenance during non-peak demand times
(back-up system)
Faster implementation time leads to quicker
compliance
Allows priorities to be placed on addressing
areas of most significant need
Area approach results in less community-
wide disruption
Passive anti-terrorist measure (spread out
facilities)
Staff must address operational needs at two or more
locations
Chemical storage at multiple locations
Requires securing of multiple sites
"No Treatment" Option
Pros Cons
Lower cost )` Failure to meet mandated standards could result in strict penalties
No physical disruption from the Minnesota Department of Health possibly including a
Notice of Violation (NOV) or Administrative Penalty Order (APO).
Under an APO, the State has the authority to levy a $1,000 per day
fine on municipalities.
)` Future conditions may wan'ant the City having to issue a "Boil
Order" to ensure safe drinking water.
)` Odor in the water is likely to increase.
)` h-on and manganese concentrations may shield bacteria from
chlorine meant to kill them.
)` Water quality not likely to meet the expectations of residents and the
business community
Memorandum
April 7, 2004
Page 4
After reviewing the incremental, multiple plant treatment approach and consideration of the pros and cons
associated with each, the Citizen Advisory Panel unanimously suggested that the Chanhassen City Council
proceed with steps necessary to further investigate and implement a multiple treatment plant approach to address
the City's short and long-term water supply and treatment needs.
The Citizen Advisory Panel also agreed to continue its service to the City Council and the community as needed
in the future to provide input on plans for system improvements and con'esponding funding mechanisms.
The Chanhassen City Council met on January 5, 2004 in a work session to review the work of the Citizen
Advisory Panel and to discuss their recommendation that a multiple treatment plant scenario be pursued as
the next step in improving water treatment in Chanhassen. The meeting also included a brief overview of a
utility rate study that was being conducted to address water system financial needs including future water
treatment improvements. Council questioned if treating 80% of maximum day demand should be the
criteria used for treatment since most of the demand at maximum day is used for irrigation. Also, Council
questioned if the phased approach in the Lotus Lake well field was cost effective based on the short term
water demand projections. In addition, Council questioned if the multiple water treatment approach is more
cost effective versus building both water treatment plants at this time based on current low interest rates
and because construction costs will be higher in the future. Staff feels to answer most of the questions
Council raised at the January 5, 2004 work session and to further define the scope of water treatment a
consultant should be hired.
Staff envisions the following proposed schedule for the project:
Task Item
Ground Water Modeling update in Lotus Lake Well Field
Pilot Plant Modeling Report
Preliminary Design/Site Plant Review
Final Design
Start Construction
Substantial Completion
Completion Date
June 2004
June 2004
September 2004
February 2005
June 2005
February 2006
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