E-4. West Water Treatment Plant: Authorize Solicitation of Proposals and Preparation of Feasibility ReportCITY OF
CHANHASSEN
7700 Market Boulevard
PC Box 147
Chanhassen, MN 55317
Administration
Phone: 952.227.1100
Fax: 952.227.1110
Building Inspections
Phone: 952.227.1180
Fax: 952.227.1190
Engineering
Phone: 952.227.1160
Fax 952.227.1170
Finance
Phone: 952.227.1140
Fax 952.227.1110
Park & Recreation
Phone: 952.2271120
Fax: 952.227.1110
Recreation Center
2310 Coulter Boulevard
Phone: 952.227.1400
Fax: 952.227.1404
Planning &
Natural Resources
Phone: 952 227.1130
Fax: 952.227.1110
Public Works
7901 Park Place
Phone: 952.227.1300
Fax: 952.227.1310
Senior Center
Phone: 952.227.1125
Fax: 952.227.1110
Website
www.ci. chanhasse n.m a us
5 -4
MEMORANDUM
TO: Todd Gerhardt, City Manager
FROM: Paul Oehme, Dir. of Public Works /City Engineer q, O
DATE: November 10, 2014
SUBJ: West Water Treatment Plant Project No. 15 -03: Authorize Solicitation
of Proposals and Preparation of Feasibility Report
Ili UNI
"The City Council authorizes preparation of feasibility report and solicitation of
proposals to consultant firms for the West Water Treatment Plant.
City Council approval requires a simple majority vote of the City Council present.
The East Water Treatment Plant was constructed in 2005 and treats about 80% the
community's water.
The 2003, a water treatment plant study recommended treating the east well field
wells first since these were the wells that have the highest iron and manganese
content. Water treatment for the west well field was planned to be phased in as
needed.
The City purchased a piece of property at the time the Lake Harrison Development
was approved for a treatment plant and for a small park. The location is at the south
end of Manchester Road at the intersection of Lake Harrison Road and Galpin
Boulevard.
On July 28, 2014, the City Council reviewed options to treat the water from the
western wells for iron and manganese.
DISCUSSION
Currently, the West Water Treatment Plant is programmed for construction in 2023.
Originally this plant was programmed in the CIP for 2012; however, with the down
turn in the economy in 2008, the plant was delayed.
Chanhassen has some unique water quality issues, caused by the high zone's
untreated water and the way it directly influences portions of the city's treated low
Chanhassen is a Community for Life - Providing for Todayand Planning forTomarrow
Todd Gerhardt
November 10, 2014
West Water Treatment Plant
Page 2
zone areas. The area, referred to as the " Minnewashta Loop ", comprises Chanhassen's western
border and rums from Highway 5 north up Minnewashta Parkway to Highway 7 then east to
Highway 41. This area is a large hydraulic loop linked to the low zone's treated water on the
southern end and the high zone's untreated water on the northern side at Highway 7 and Highway
41. During periods of normal to low use, this area is served with treated water, however, in periods
of high use the demand is heavily supplemented from the high zone. This condition causes
troublesome rusty water complaints throughout the Minnewashta Loop area. The only remedy for
these complaints is to perform localized hydrant flushing to remove the discoloration.
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Unfortunately, this activity only introduces more untreated high zone influence on the low zone and
also has a dramatic effect on chlorine residuals. Chlorine is added to the water to guard against
disease causing pathogens. The City's untreated water has a high chlorine demand because it is rich
with iron and manganese. These elements chemically oxidize together with chlorine in distribution
piping, bringing them out of solution and creating discolored material. This condition makes for an
uneven chlorine residual throughout the City; higher in the east and lower to the west.
Wells 3 and 9 located on Galpin Boulevard north of Highway 5 are low zone wells directly
connected to the distribution system and are not treated by the East Water Treatment Plant. These
supportive wells offer water production in periods of high city demand; however, they also bear
negative water quality issues upon the low zone. The areas most affected with discolored water
from these wells are along W. 78th Street and include Arboretum Village Townhomes, the
Vasserman Trail area, and the Walnut Grove HOA.
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Todd Gerhardt
November 10, 2014
West Water Treatment Plant
Page 3
Treated areas of the city not under any direct or indirect influence from the high zone experience
very little or no discolored water throughout the year.
Treatment of West Wells
The West Plant is currently planned for a total capacity of 6,000 gpm. The future plant is proposed
to have the same gravity cast -in -place treatment process as the East Water Treatment Plant. The
plant would be designed for the ultimate treatment capacity needs of the city and bring all the
western wells and future wells to the plant for treatment. The plant would be designed so treated
water could be able to be pumped in the low and high zones.
A phased -in option for water treatment is also an option. This option would construct a smaller plant
to treat the average day use from the existing wells in the high zone and not treat the peaking wells at
this time. In the future, peaking wells and future wells would be treated as needed. If phased -in
treatment is the preferred option, staff envisions phasing in treatment to the west well field starting at
the West Plant site on Lake Harrison Road
To determine the best approach for water treatment, a detailed feasibility study should be completed
to gain a better understanding of the type of construction, projected chemical feed rates and to gain a
more in -depth look at costs and needs. Also included in the study should be a public involvement
component.
Staff is requesting to send out a Request For Proposals for feasibility study for treating the west well
field. A minimum of three firms will be invited to send in proposals for the feasibility study.
The scope of the study would include:
✓ Reviewing the city's treatment needs for the west well field.
✓ Detailed cost estimates for water treatment options both central plant and phased -in options.
✓ Public Involvement — one open house meeting.
✓ Council Work Session meetings.
✓ Renderings of preferred treatment option.
If the Council decides to move forward with a west water treatment option the cost information
would then be included in a future rate study.
SCHEDULE FOR FEASIBILITY STUDY
Council Considers Approving Consultant Contract for Feasibility Study December 8, 2014
Feasibility Report Spring, 2015
Water Rates Study Review Fall, 2015
gAmg \pub1ic \_2015 projects \15 -3 west water treatment plant feasiblity study \111014 bkgd west wtp appm auth prep feasiblity report.doc
CITY OF CHANHASSEN
CARVER AND HENNEPIN COUNTIES, MINNESOTA
DATE: November 10, 2014 RESOLUTION NO: 2014 -XX
MOTION BY:
SECONDED BY:
A RESOLUTION AUTHORIZING SOLICITATION OF PROPOSALS AND
PREPARATION OF FEASIBILITY REPORT FOR THE
WEST WATER TREATMENT PLANT PROJECT NO. 15-03
WHEREAS, a West Water Treatment Plant is programmed for construction in 2023; and
WHEREAS, to determine the best approach for water treatment for the west well field, a detailed
feasibility study should be completed; and
WHEREAS, the feasibility study would help to gain a better understanding of the type of
construction recommended, project chemical feed rates and gain a more in -depth look at costs and needs.
NOW, THEREFORE, BE IT RESOLVED that the Chanhassen City Council hereby authorizes
the City Engineer to solicit Requests For Proposals for preparing a feasibility study for treating the west well
field.
Passed and adopted by the Chanhassen City Council this 100' day of November, 2014.
ATTEST:
Todd Gerhardt, City Manager Thomas A. Furlong, Mayor
YES NO ABSENT