A-2. West Water Filtration Plant Preliminary Plan ReviewCITY OF
CHANAAS3EN
7700 Market Boulevard
PC Box 147
Chanhassen, MN 55317
Administration
Phone: 952.2271100
Fax 952.2271110
Building Inspections
Phone: 9522271180
Fax: 952.2271190
Engineering
Phone: 952 227.1160
Fax: 952.227.1170
Finance
Phone: 952.227.1140
Fax 952.227.1110
Park & Recreation
Phone: 952.2271120
Fax: 952.2271110
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: 952.2271300
Fax 952.227.1310
Senior Center
Phone: 952.227,1125
Fax: 952.227.1110
Website
www. ucha nhassen. m n. us
4-9."�
MEMORANDUM
TO: Todd Gerhardt, City Manager
FROM: Paul Oehme, Dir. of Public Works/City Engineer
DATE: July 27, 2016 bKd, �� —
SUBJ: West Water Filtration Plant Project No. 15-03: Preliminary Plan
Review
BACKGROUND
On February 22, 2016, the City Council approved a consultant contract with WSB
and Associates for the West Water Filtration plant.
At the May 9, 2016 work session, the City Council was presented with the
preliminary design for the West Water Filtration Plant.
On June 2, 2016, an open house was held for the proposed project.
DISCUSSION
Since the work session on May 9, 2016, staff has been working on refinements to the
layout. At the open house, staff heard concerns about the size of building. Staff has
been working to try to reduce the building footprint and on ways to screen the
building.
The filtration plant is still being designed for the necessary capacity needed for the
city. The iron and manganese filtration plant is planned for a total capacity of 6,000
gpm. The plant is proposed to have a process that is very similar to the gravity cast -
in -place treatment process as the East Plant to provide consistency in the plant
operations and finished water quality. The plant will be designed for the ultimate
treatment capacity needs of the city and will bring all the western wells and future
wells to the plant for iron and manganese filtration. The plant would be designed so
treated water will be able to be pumped in the low and high zones.
Building Layout Changes
The building layout has been changed since the May 9u' work session as follows:
I. The electrical room has been moved from the south side of the building to the
east side.
2. The generator room has been moved from the west side of the building to the
east side.
Chanhassen is a Community for Life - Providing forTodayand Planning for Tomorrow
Todd Gerhardt
West Water Filtration Plant: Plan Update
July 27, 2016
Page 2
3. The non -water production area which includes the control room, chemical rooms, mechanical
and electrical rooms have been lowered 6 feet in elevation to better screen this area of the
plant and allow for a more gradual driveway grade. There are now stairs from the non -water
production area to the process room.
4. The aeration process has been eliminated. The building for the aeration equipment has been
eliminated to reduce the height and size of the building.
5. The size of the detention tank has been reduced by half.
Eliminating the aeration process will require more chlorine to be used in the filtration process to
oxidize the iron in the water supply although it will not affect the amount of chlorine that will be fed
downstream into the water distribution system for disinfection purposes. WSB estimated that more
chlorine will be consumed on a daily basis due to the elimination of the aeration process. Also, as
the chemistry of the west well field potentially changes with the addition of new wells, the filtration
process may become less efficient without the aeration process but the plant should continue to
reduce the iron and manganese to acceptable concentrations in accordance with recommended Ten
States Standards.
The overall building length has been reduced from 178' 4" to 138' 4". The most the building is
visible above ground is approximately 17' without a sloped roof.
Building Exterior Design and Landscaping
The goal of the site design is to have the building set into the hillside as much as possible to take
advantage of the topography to decrease visual impacts. The building's exterior would be built with
maintenance free materials and finishes such as stone, manufactured stone products or brick similar
to the East Plant. Doors and windows, as well as, other fenestration could have more of a residential
look than the East Plant and have a prairie -style architectural feel. Staff would like to use "earth
tone" colors for exterior finishes. Below is an example of a prairie -style architectural structure.
The use of evergreens and berms will likely be used at strategic locations to visually break up the
building. The rest of the site and park will have additional landscaping with mainly deciduous trees.
g:\eng\public\_2010-2015 public projects\_2015 projects\15-03 west water treatment plant feasiblity study\backgrounds presentations\062016 bkgd cc
ws plan review wwtp - rev 062216.doc
Todd Gerhardt
West Water Filtration Plant: Plan Update
July 27, 2016
Page 3
Preliminary Cost Estimate
The preliminary construction cost is approximately $19.5 Million which includes approximately $2
Million to construct the raw water lines from the west wells to the plant. More accurate cost
estimates will be prepared at the completion of the 60, 90, and 100 percent complete phases of the
design.
The City has made application through the Minnesota Department of Health for grant and loan funds
to assist in financing the plant. These funds come with specific requirements that would add cost to
the plant construction but would lock in the interest rate at 1% which is significantly below the rate
the City could sell bonds.
Site Acquisition
The City purchased the site for the filtration plant in 2005 at the time the Lake Harrison development
was approved. The City identified several sites for the future plant before the purchase was made.
The parcel the City purchased was viewed as the best site for a future filtration plant. The site of the
Children's Learning Center at the corner of W. 78th Street and Galpin Boulevard was one of the sites
the City evaluated for the future filtration plant. The Children's Learning Center does have an outlot
that is currently not being developed. This outlot is large enough for the filtration plant. It is
estimated the outlot would be valued at about $1,000,000. The soils in the area are known to be poor
and it is likely a building constructed on the outlot would need to be supported by piling or other
structural techniques. The cost to extend raw water main from the current location to the plant and
the necessary truck distribution water main is estimated to cost $1,500,000. If the plant were to be
constructed farther south of W. 78th Street, the cost for constructing the trunk water main and the
distribution main would be significantly higher.
SCHEDULE
City Park & Recreation Board Meeting
Complete 90% Design and Cost Estimate
City Council Meering to Present 90% Design
Neighborhood Meeting to Present 90% Design
Complete 100% Design and Cost Estimate
Planning Commission Meeting
City Council Approves Bidding Documents
Bid Opening
City Council Considers Award of Construction Contract
Construction
Water Filtration Plant Start-up
Attachments: Floor Plan
Elevation Views
Site layout
Site Acquisition Memorandum
c: Greg Johnson, WSB & Associates
June 28, 2016
August 2, 2016
August 8, 2016
August, 2016
August 31, 2016
September 6, 2016
September 12, 2016
October 11, 2016
October 24, 2016
November, 2016 — April, 2018
April, 2018
g:\erg\public\_2010-2015 public projects\_2015 projects\15-03 west water treatment plant feasiblity study\backgrounds presentations\062016 bkgd cc
ws plan review wwtp - rev 062216.doc
_C
EL. 1016.17 r -----J
— — — — _
I I
II IL_____J 992
EL50
Fill— 1i'1
EL. 1027.00
I PROPOSED GRADE)
I
— I — — — —
�____
IL EXISTING GRADE
L_________________________ _I___________
— l , ,________ ________
S
r L ------J C I LJ LJ LJ
EL. 985.50
I I
_ rI L____
L
WEST ELEVATION VIEW
EL1027.00
EL 1016.33 es
111111
,im,,m,
— —. 1000.00 J
EL. 988.50
EL 980.50
EL. 1016.33— —
r — --� EL1016.17
l— — — — ——
EL. 1008.50 ® �'�--- ------
—
j PROPOSED GRADE
— — — — — — EXISTING GRADE l� I
— — — — — — — — — — — — — — — — — I
— —
I I
—_____ _____ ___J L_____J I EL. 992.50
LJ___ -____LJ_____-__ L J-_____-_ F - �, L—_____J
II II
EL. 988.50 __ I ___"
_______,I II EL. 985.50
-----------------------------------------
-
___----_____ _____J
------------------------------------
------
L J5
EL 980.50 -----
-------------------
2EAST ELEVATION VIEW
0 s '. le,
Ir..rmmmmi
z
z O
�.
Lu
LuOz
LLI
z
�iuJ
H
Lu ot
Q LLLu
Q
� V
CIN PROJECT NUMBER
WSB PROJECT NUMBER 0 01694694 —720
1PRELIMINARY ELEvAnoN VIEWS I ELEV VIEWS
-
901 %enla Avenue South,
Mlnne00
MN 5W6
WSB
T.l:( )W
Tel: 19s3j 541-4800
Fax:(/63)541-1]00
Projeotu 01694-920
-
June 2Z 3016
WEST WATER TREATMENT PLANT CONCEPT
[ Lr TYPICAL PLANTINGS
CUL-DE-SAC
WITH PARKING
NO MOW GRASS
QQ'
FUTURE PRE -K
PLAY
FUTURE
_MENTA
PLAY
\ yip
FUTURE
\ SHELTER
\ MAINTENANC�^JE'�'J!'�,�'�� )
A STRIP
IM
\ 7
9� \ EXISTING POND
F
• r /S
0
'00
� 90
EVERGREEN TREE
(TYP)
WATER
TREATMENT
PLANT
KS
NO MOW
GRASS
ORNAMENTALTREE
(TYP)
DECIDUOUS SHADE TREE
(TVP)
- ADA
ACCESSIBLE
TRAIL
DRIVE
1 j
LAWN
4
JT
J
O
m
2
4
V
CITY OF
MEMORANDUM
CHMSEN
•��; 952<t 1.7;1
TO: Todd Gerhardt, City Manager
war"aG`um"ru
P,jP. s7
FROM: Pau! Oehme P.E., Dir, of Public Works/City Engineer
,.. :5seo.1.1r.56317
L Meet the Minnesota Department of Health Requirements.
Senior
P'nw - 95252 22'2? 1 1185 1
DATE: June 21, 2005
Administration
3. Reduce colored water and taste/odor problems.
ne 952227 iiia
4, Mitigate bacteriological risks in the distribution system.
Vas B52Ct71110
SUBJ: West Water Treatment Plant Land Acquisition Discussion
Project No. 05-06
Building Inspections
B. On the west well field:
FP-.r. 952.'t27.1180
1. Assess the reliability of sequestering.
r'v 952 22,11190
This memorandum is intended to summarize the decisions made by the City since the
2003 Water Master Plan was completed and identify cost benefit analysis for land
Engineering
E ,62,227.1E7
acquisition for a future wast water treatment plant.
Fix m,22271 ti9
BACKGROUND
Finance
- :r. 912 22" 11 ad
ax :,.5z Y27 ii1:;
In January, 2003, a Master Plan was completed for the City of Chanhassen. This plan
included recommendations for water supply, treatment and distribution the system.
Park &Recreation
Some of the recommendations in the plan were of concern to the City Council and the
Citizens Advisory Panel (CAP) and a review by a separate consultant of the plan was
recommended. The concerns included phasing in of the water improvements, cost
analysis, and recommendations for a central plant,
%22z! 14C:'
�521Y1goa
On August 20, 2003, SEH Consultants completed a review of the 2003 Water Master
Planning &
Plan and recommended a stepwise approach to address the City's water quality
Natural Resources
issues. This approach proposed to address the most urgent needs for the Cit and
Y
F:rpaX iS952 21i 27, 11
]`. then
;a+: iq
move on to address less urgent water needs.
t•,
quality
Public Works
The approach laid out by SEH was as follows:
1591 Fri �,.a
•��; 952<t 1.7;1
:5222: 1 ov
A. On the east well field:
L Meet the Minnesota Department of Health Requirements.
Senior
P'nw - 95252 22'2? 1 1185 1
2, Meet the Safe Drinking Water Act requirements.
-
952227 n1,
3. Reduce colored water and taste/odor problems.
4, Mitigate bacteriological risks in the distribution system.
Website
5. Expand supply without compromising the first four objectives.
B. On the west well field:
1. Assess the reliability of sequestering.
2. Phase in treatment as needed.
On December 18, 2003, the CAP met and discussed the SEH August 20, 2003
recommendations. The CAP unanimously suggested the Chanhassen City Council
proceed with steps to investigate and implement a multiple treatment plant approach
to address the City's short- and long-term water supply and treatment needs.
The Clly at Chanhassenir µ,� i" �;.=s ;;� .7,. .. ., 1,-,,,,, •.
Todd Gerhardt
.lune 21, 2005
Page 2
The Chanhassen City Council met on January 5, 2004 in a work session to review the
work of the CAP and discuss the recommendations. The meeting ended with the
Council approving the CAP's recommendation for the multiple treatment plant, On
the January 26, 2005 regular agenda, the Council adjusted the connection charges and
water rates to help pay for the future water treatment improvements.
On April 12, 2004, the Council met and reviewed the discussions the CAP and City
Council made from December 2003 to January 2004 and evaluated the water
treatment alternatives. At this meeting, it was determined to build the (East) Lotus
Lake water treatment plant to its ultimate design capacity, 6,000 gpm, instead of the
phased approach as recommended in the August 20, 2003 SEH memorandum. This
discussion was made because it was anticipated the expansion to the plant would be
needed only a few years after the first phase of the plant was built because of
projected City growth. Also, by building the treatment plant to the ultimate capacity
under one construction project, costs would be less and disruption to the
neighborhood by construction traffic would be minimized.
The Council directed staff to obtain quotes for three studies:
1. Groundwater Modeling Study of the Lotus Lake Well Field. This report was
needed to identify if adequate water supply was available in this area to
supply the plant for the ultimate design capacity.
2. Pilot Plant Modeling Study. This report was needed to identify the best way
to treat the water at the Lotus Lake Well Field.
3. Preliminary Investigation Study. This report was needed to define the best
location to build the plant.
At the June 14, 2004, Council work session staff presented the findings of the three
reports to the Council. The Council accepted the groundwater modeling and pilot
plant study. The Council requested additional information including some cost and
benefit analysis for the two available sites, the "Ready Mix Site" located just north of
TH 5 by the pedestrian bridge and the South Lotus Lake Park site. The two sites
identified in the repots were the only available properties near the east well field the
City owned. Both sites are very tight and have unique challenges for constructing a
water treatment plant.
At the August 9, 2004, work session staff updated the Council on the recommended
location of the Lotus Lake well field site. The Council unanimously approved
moving forward with sighting the water treatment plant on the "Ready Mix Site" by
the TH 5 Pedestrian Bridge. Since the August 9, 2004 Council meeting, staff has
been working on the design of the East Water Treatment Plant. The east plant is
scheduled for construction start in July 2005 and to be operational in 2006.
The August, 2003 SEH memorandum recommended the City assess the possibility of
sequestering the iron and manganese for the west wells. Sequestering was also
Todd Gerhardt
June 21. 2005
Page 3
reviewed in the 2003 Master Plan. The sequestration process adds polyphosphates to
the effluent water and in turn reduces the formation of insoluble iron and manganese
oxides which cause the water discoloration, staining, and taste and odor problems.
Staff obtained costs for sequestering the west well water. Using average pumping
rates from these wells, chemical injection cost will average about $32,000.00/yr.
Initial startup costs will be approximately $5,000,00 for tanks, pumps and injection
point installation.
The effectiveness of sequestration can be limited by concentration of constituents and
water temperature. In addition, polyphosphates can begin to break down within 24
hours or less, reverting to an orthophosphate which has no sequestering capability.
Also, orthophosphates can serve as a nutrient to water system bacteria and other
microbes. Hence, retention time within the water system is a critical element for
deciding on its use. The recent testing done on the wells and pumping records
concluded that the residence time in the west well field during the fall and winter
months is estimated to be too long for sequestering to be effective. In addition the
west side of the City has numerous long dead ends that are not looped which make
sequestering ineffective at times. The 2003 Master Plan deemed this process not
feasible. The analysis showed sequestration would most likely not be effective
during the fall and winter months when the process is needed the most. Due to the
high annual cost of chemical injections staff is not recommending sequestering be
considered in the west well field. A treatment plant that removes the iron and
manganese is the recommended method for improving the aesthetics of the west well
water.
LAND ACQUISITION FOR WEST TREATMENT PLANT
The 2004 and 2005 Capital Improvement plans adopted by the Council included a
project, #W-031, for land acquisition for the west (Galpin Area) water treatment
plant. Over the past two years, staff has looked for opportunities to purchase land in
the Galpin area for a future water treatment plant. Staff began site evaluations based
on the 2003 Water Master Plan and evaluated other sites in the corridor as they were
put on the market and became available. The City has not considered eminent
domain or land taking at this time for water treatment plant site.
Over the past two years, five sites were evaluated for a water treatment plant in the
Galpin Boulevard area. This area was chosen based on its close proximity to the west
wells were existing infrastructure already is in place. The closer the water treatment
plant is to the existing and future wells, the less raw water transmission mains will be
needed.
Through the Highcrest Meadows and the Lake Harrison development, the City is
considering installing raw water transmission mains to be used for a future treatment
plant (Section A). The transmission mains are proposed through these developments
because it is the most cost effective alignment to bring the raw water from Well Nos.
Todd Gerhardt
June 21, 2005
Page 4
7 and 8 to a future treatment plant in the Galpin Boulevard area. Any other alignment
along existing street right-of-way will cause significant disruption to the property
owners and the traveling public and would be more expensive. All sites evaluated
would utilize the transmission mains.
SITE ANALYSIS
Alternative Site 1—This site is located at the southwest quadrant of the intersection
of Galpin Boulevard and Topaz Drive. The site is approximately 5.4 acres. The
majority of the site is on a steep hill with few mature trees. The site is centrally
located around the western wells and is close to the distribution network. The site is
also centrally located between the high zone and the low zone areas. The treatment
plant would be designed to pump water to the high zone and the low zone without the
need for an additional external booster pump station. The site allows for the
treatment plant to be built into the hillside and partially screened from the existing
and future residential neighborhoods (see attached concept plans). Building the
treatment plant into the hillside will add approximately $100,000 to the construction
of the plant. Properties on the east side of Galpin Boulevard would be screened from
the plant by a berm. in addition, these properties are setback from Galpin Boulevard
by a wetland along the east side of Galpin Boulevard. Additional raw water and
distribution pipe network would be required to bring the raw water from Well Nos. 9
and 3 to the plant and distribute it out into the network at an estimated cost of
$390,000 (Section B). The purchase price for this site is estimated at $1,300,000.
The Parks Department has identified this site as a good location for a small
neighborhood park and sledding hill. Funds for purchasing the property would come
from the water utility fund and park dedication fund, The 2003 Master Water Plan
considered this site desirable for a water treatment plant.
Alternative Site 2 — This site is located at the southeast quadrant of the intersection of
Galpin Boulevard and Longacres Drive. Well No. 3 is south of the site and Well No.
9 raw water transmission main is close to the site. The site is also close to the high
and low pressure zones. The treatment plant would be designed to pump water to the
high zone and the low zone without the need for an additional external booster pump
station. A 20" raw water transmission main would be required to be extended along
Galpin Boulevard (Section B) from the Lake Harrison Development to the site in
addition to some distribution mains. The cost for the piping is estimated at $410,000.
Based on the topography of the land and future access of the site for development, it
is estimated 4.5 acres of land would be needed for the plant. The current land value is
estimated at $1,269,000 using $282,000/acre. The plant would be built in a
residential neighborhood and the lay of the land does not allow for much screening.
The treatment plant would be visible to the Longacres neighborhood on the west side
of Galpin Boulevard. The property is currently not for sale, If the City would
condemn the property, costs for land are anticipated to be higher. The 2003 Master
Water Plan rated this site low and did not consider it a desirable site because the
shape of the parcel would make it difficult to provide adequate buffer between the
water treatment plant and the adjacent residential parcels.
Todd Gerhardt
June 21; 2005
Page 5
Alternative Site 3 —This site is located at the northwest quadrant of the intersection of
Galpin Boulevard. and Walnut Curve. This property was for sale in 2004 and staff
evaluated the property at that time for a water treatment plant. The property is
approximately five acres, however, about 25% of the property is considered wetland.
The property is also very narrow. Based on the setback requirements for the
treatment plant from wetlands and adjacent properties, it was determined the property
was not adequate for a treatment plant.
Alternative Site 4 — This site is located at the northwest quadrant of the intersection of
Galpin Boulevard and 78"' Street. This property is for sale and staff has reviewed the
site for a water treatment plant. The site is approximately seven acres and is located
near a trunk sanitary sewer that is on the north side of the property. Approximately
50% of the property is wetland. Staff obtained soil borings for this site which show a
significant amount of poor soils at the site at the buildable location. The setback
requirements from the Department of Health for the wetlands and the sanitary sewer
make the site too small for a water treatment plant.
Alternative Site 5 — This site is located at the southwest quadrant of the intersection
of Galpin Boulevard and 781h Street and is approximately 8.08 acres. The south side
if the property abuts TH 5. This property is for sale and is currently zoned residential
low density. The property has a small wetland on the west side of the property.
Access would only be available on the west end of the properly off of 781h street.
Based on the available access point and the wetlands, the entire site would need to be
purchased to build a water treatment plant. The property is being marketed at $10/sf..
or $3,520,000 for the 8 acres,
The site is in the low pressure zone and a substantial amount of piping improvements
would be required to make the site functional for water treatment. A 20" raw water
transmission main would be needed along Galpin Boulevard from the Lake Harrison
Development to Well No. 3 similar to Site 1 and Site 2 needs (Section B). The
existing 16" main between Well Nos. 3 and 9 would need to be removed and replaced
with a new raw water transmission main (Section Q. A new 24" raw water
transmission main would be required from Well No. 9 to the treatment plant (Section
D). These improvements are necessary to bring the raw water to the treatment plant,
In order to have the plant service the high pressure zone, an external booster pump
would need to be built at Sites I or 2 or a 16' dedicated high zone distribution main
would be required along Galpin Boulevard from the treatment plant to Longacres
Boulevard. For this analysis, the 16' distribution pipe was used because it is less
expensive then a booster pump station. The total estimated cost for the raw water
transmission and distribution piping to make this site adequate for water treatment is
$1,071,000.
The site is away from residential parcels and therefore considered a desirable site.
However, due to the land cost and additional infrastructure to make this site a viable,
the site is not considered desirable.
Todd Gerhardt
June 21, 2005
Page 6
Summary of Site Issues
Sites 3 and 4 were not included in the summary because they did not meet the
minimum requirements for the west water treatment plant site.
CONCLUSION
Site 5 costs substantially more then Sites 1 and 2 and is therefore not recommended
for a treatment plant site.
Based on the available information, sites 1 and 2 cost benefit is very similar when
compared to the estimated $9,000,000 to construct the treatment plant. Since Site 2
land is not available for purchase and is not a desirable site for a treatment plant based
on screening and buffering issues in a residential area, it is recommended the City
consider purchasing Site t for the west water treatment plant.
Attachments
9 kenglpublid05-06-west wmer Iiealmenl planNneroo G2I05 lino aquisiuon.Acx
Added
S1TGS
Facility Cost
Screening/
Piping Cost
Land Costs
Land
for Screening
Bufferin g
Availability
Site 1
$100,000
Adequate
$390,000
$1,300,000
Available
Site 2
-
Not a
$410,000
$1,269,000
Not
desirable site
available
Site 5
NA
$1,071,000
$3,520,000
Available
Sites 3 and 4 were not included in the summary because they did not meet the
minimum requirements for the west water treatment plant site.
CONCLUSION
Site 5 costs substantially more then Sites 1 and 2 and is therefore not recommended
for a treatment plant site.
Based on the available information, sites 1 and 2 cost benefit is very similar when
compared to the estimated $9,000,000 to construct the treatment plant. Since Site 2
land is not available for purchase and is not a desirable site for a treatment plant based
on screening and buffering issues in a residential area, it is recommended the City
consider purchasing Site t for the west water treatment plant.
Attachments
9 kenglpublid05-06-west wmer Iiealmenl planNneroo G2I05 lino aquisiuon.Acx
Alternate West
Water Treatment Plant Sites
a r
Hill
Park
IV
e
Well �
Site 1 "� i
e---_ 8
y
t
Well & :� -j Section A 1 Section B
It Watermain from Site 1
Raw Watermain a
t for Well 7 & 8 Well #3
D
7 _
Slte 2
$
rll 3
I
18 m
•�'�..� rSection C�]
'24 Existing Watermain)
8 From Well 93 to #9
Well 9
Site 3 P��', 12
f �re s
T.r tr
8 8 8
Site 4 2f Section 10
= Y Watermain from Site 5
To Well #g
Y8 —� 8 4
r.afx�rvt: m i ti�ard g _ It; _• -
12' 20
20
Site 5
-- 72t,c-,.4g
June, 2005
G:{ENGVvleen�Lng FrryoclsiPeuMlfN}iTiealSifea4Sifvs.mvtl