1e. Well No. 5, Specs & Bids I e
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CITY OF
, , CHANHASSEN
690 COULTER DRIVE • P.O. BOX 147 • CHANHASSEN, MINNESOTA 55317
1 \ (612) 937-1900 • FAX (612) 937-5739 Action by City Administratot
Endorsed .
1 MEMORANDUM Modified
Rejected —
Date /-11290_
TO: Don Ashworth, City Manager pate Submitted to commission
' FROM: Gary Warren, City Engineer
Date Submitted to Councl
DATE: January 17 , 1990 ° ' 0
SUBJ: Approve Specifications and Authorize Advertising for Bids
for Test Well and Optional Observation Well Construction
1 for Well No. 5 , South Lotus Lake
Project No. 89-4A
1 As directed by the City Council on November 2, 1989,
specifications have been prepared for construction of a test well
1 and optional observation well for a new glacial drift well at the
South Lotus Lake wellhouse site. The specifications are complete
and are available in Engineering. This is the preliminary step
to confirming whether the drift material identified in the boring
logs at this location is capable of supporting a 500 gallon per
minute well for the City. This element is a part of the original
scope as identified in the preliminary water supply investigation
' report prepared by B. A. Liesch Associates, Inc. (attached) and
is estimated to cost $20,000 . If the test well proves productive
as anticipated, the project schedule proposes completion of the
' production well by June 15 , 1990 , in time for our peak summer
demand.
It is therefore recommended that the specifications for test well
1 construction as prepared by B. A. Liesch & Associates, Inc. be
approved by the City Council and authorization given to advertise
for bids .
Attachments: 1. Preliminary Engineering P En ineerin Report For Addition of
Two Wells dated December, 1989.
1 2 . Project schedule.
c: Jim Bullert, B. A. Liesch Associates, Inc.
' Jerry Boucher, Utility Superintendent
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PRELIMINARY
ENGINEERING REPORT
FOR ADDITION OF TWO WELLS
PREPARED FOR:
THE CITY OF
CHANHASSEN, MINNESOTA
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I DECEMBER 1989
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I PREPARED BY:
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-7;i744,;;,,,,;- BRUCE A. LIESCH ASSOCIATES, INC.
I HVDROGEOLOGISTS • ENGINEERS • ENVIRONMENTAL SCIENTISTS
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PRELIMINARY
ENGINEERING
REPORT • I
FOR
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ADDITION OF TWO WELLS ,
FOR THE 1
CITY OF CHANHASSEN
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CITY OF CHM thSSEN
DEC 2 91989
ENGINEERING DEPT.
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I hereby certify that the this document was written by me or under my direct supervision
and that I am a duly Registered Professional Engineer under the laws of the State of
Minnesota.
cash.J-
J es Bullert, P.E. I
R gistration No. 13961
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ITABLE OF CONTENTS
IPAGE
IIntroduction 1
Description of Existing System 1
IProposed Revisions to System 4
Project Schedule 7
Estimated Cost 8
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- INTRODUCTION
' This report investigates the feasibility of installing two municipal drinking water wells in
Chanhassen to provide additional water supply of approximately 1500 gallons per minute.
The initial recommendation is to locate these wells at existing pumphouses to minimize
' piping and control costs. This report will evaluate the feasibility of this construction
relative to system hydraulics, room for additional equipment of the pumphouses and
expansion of the control systems.
DESCRIPTION OF EXISTING SYSTEM
' The existing municipal water supply system in Chanhassen consists of four wells and three
storage tanks serving two service areas. These facilities are described as follows:
Well No. 2 1000 GPM
Well No. 3 1000 GPM
Well No. 4 975 GPM
School well 250 GPM
' Water tower (low service area): 100,000 gallons
Water tower (high service area): 200,000 gallons
Water Storage tank (low service area): 1,500,000 gallons
Booster Pump Station (low to high service area): 1000 GPM
A water system analysis prepared in 1985 by ORR-SCHELEN-MAYERON & ASSOCIATES,
INC. detailed many of the shortcomings of the existing system. Two of the major
recommendations in the report have been implemented; specifically, the construction of
the 1.5 million gallon storage tank near Co. Road 17 and Lake Lucy Road and the
construction of an 18 inch watermain along Lake Lucy Road from Co. Road 17 to Galpin
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Boulevard. The most pressing current need is additional well capacity. The OSM report
6 recommended construction of an additional well by the year 2000 and ultimately two
additional wells. The drought conditions of the past few years have, however, revealed
an immediate need for additional well capacity. During the summer of 1989, all wells
operated continuously over extended periods. Residential and industrial growth will
increase this demand to the point of creating water shortages should dry summer
conditions again occur. Construction of two wells is recommended, one to provide reserve
capacity should any well fail during a peak usage period. Construction of the two
additional wells will provide for current water needs and some future population increases.
It is not the scope of this report to project water needs into the future. However, we
recommend that a revised study of the water needs in Chanhassen be prepared in the near
future. ,
The water system as it now exists operates as follows: '
There are three service areas operating at different pressures (elevations) in Chanhassen. '
The low service area is served by well pumps 2, 3, and 4 and by a 100,000-water tower and
a 1,500,000 gallon ground storage tank. Pumps 2, 3, and 4 are controlled to maintain a
water elevation in the two storage tanks near 1120. This elevation provides adequate
pressure to serve the users in the low pressure service area. The high service area is
served by a booster pump station, the school well and a 200,000 gallon water tower.
Normal operation has the booster pump pumping from the low service area watermain '
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system to the high service system to maintain a water elevation in the water tower of
about 1200. The School Well is used in the summer to supplement the high service area.
The School Well does not have automatic controls, but is manually started and stopped
during high consumption periods. The third service area, the Lake Minnewashta service '
area is served via a pressure reducing valve off of the high service area. The pressure
reducing valve reduces the pressure by about 30 PSI to serve the lower elevation homes '
of the Lake Minnewashta area.
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A schematic of the water system depicting the three service areas and pumping and
' storage facilities is attached. Alternative operating schemes are built into the system,
including:
' o The high service area can be served by well pump no. 3 from the low service area
while bypassing the booster pump station and the low service area.
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o The low service area can be supplemented from the high service area through
pressure reducing valves in the booster station and near Yosemite Lane and 63rd
Street.
A number of weaknesses are identified in the 1985 OSM report. Some of these weaknesses
rhave been remedied including construction of the 1,500,000 gallon storage tank and
construction of the Lake Lucy Road trunk line. The major weaknesses left to be addressed
rinclude the lack of a looped system to serve the Lake Minnewashta Area. The future
looping of this system with the low service area should be considered in any development
rto the west of the downtown area.
We have identified a few operational problems with the existing system including:
ro Well No. 3 includes a well pump and a booster pump in series. This configuration
was originally designed to produce sufficient pressure to serve the high service
area. The series operation of these two pumps"has produced a hydraulic situation
that causes the booster pump to rapidly cycle on and off, an unacceptable situation.
This has been temporarily remedied by throttling the discharge from the well pump.
With the construction of the new ground storage tank, the booster pump could be
eliminated if the well pump were modified to operate at the low service area
pressure. This would involve adding two bowls to the existing well pump and
increasing the motor and electrical control size from 75 HP to 100 HP. The
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Aestimated cost of this construction is $15,000.00. This revision will result in
I increased well pump efficiency with an estimated electrical power savings of
several thousand dollars per year. 1
Io Pressure reducing valves exist between the low service area and the high service
area. These pressure reducing valves are no longer normally needed due to the '
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' construction of the new storage tank. We recommend that they be isolated from
the system to eliminate the possibility that failure of one of them would drain the
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high service area water tower. The valves and piping should remain in place to be
used during maintenance of the ground storage tank.
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o The control system should include an alarm system to notify the operator upon low I
water pressure in either of the service areas. This can be accomplished by simply
I adding an automatic telephone dialer at the control center for each service area. I
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t o The booster station includes only one booster pump. A second pump should be
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added to assure service to the high service area should the booster pump fail. The
estimated cost of adding the second booster pump is $15,000. This addition is
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especialIy important if well pump three is modified to eliminate the booster pump
f in series with that well pump. I
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PROPOSED REVISIONS TO SYSTEM
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Revisions planned to the system at this time are the addition of two wells to increase the '
system pumping capacity by about 1,500 gallons per minute. One well will be located near
Well No. 2 and will be finished in a glacial drift formation. The other well will be located
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near Well No. 3 and will be finished in the Prairie du Chien aquifer. Each of these wells
I is further described as follows.
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IWell No. 5 (Glacial Drift Well)
It is the intent to construct a glacial drift well to produce up to 500 gallons per minute
near Well No. 2. The hydraulic limitations of the watermain in the area of Well No. 2
two dictate a practical limit for a new well in this area of about 500 gpm. A well
finished in the glacial drift should provide this capacity and will be considerably less costly
' than a bedrock well. The feasibility of a glacial drift well, however, is not easily
= predicted without constructing a test well to investigate the water bearing formations.
For this reason, we recommend construction of a test well, analysis of the test well,
followed by completion of the production well if the yield appears acceptable.
The production well will be located near the pumphouse with the watermain from the well
extending into the existing pumphouse. The well will be equipped with a submersible pump
and pitiless adaptor. The pump size will be determined by the results of the test well
analysis, but a reasonable estimate would be 500 gpm at 300 feet of head, requiring a 50
or 75 horsepower motor. Addition of 500 gpm to the watermain near Pumphouse No. 2
should not result in an unacceptable increase in pressure when both pumps are operating.
Revisions required at the pumping station include the addition of a flowmeter, a pump
' control valve and additional chlorine and fluoride feed systems. The electrical service to
the pumphouse will need to be increased and an additional circuit breaker and starter will
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need to be added for the new pump. The existing control system can be readily expanded
to accommodate the new well.
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Well No. 6 (Prairie du Chien Well)
A new Prairie du Chien well will be constructed near Pumphouse No. 3. The capacity of
this well is proposed to be 1,000 gallons per minute. This well will be a
submersible/pitiless well with the watermain routed through existing Pumphouse 3. The
piping arrangement in Pumphouse 3 is such that it would be recommended to eliminate the
existing booster pump by revising the existing well pump capabilities to pump directly into
the water system. This would involve adding two bowls to the existing pump and
• increasing the motor size from 75 to 100 horsepower. The piping arrangement in the
pumphouse would then be revised to allow installation of piping for the new well including
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pump control value, air release and flow meter. A new electrical service along with new
circuit breaker and starter will be required for the new pump. Existing controls can be
revised to start and stop the new pump. Additions will be required to the chlorine and
fluoride system to accommodate the new pump. r
The location of the proposed well has not yet been identified. The existing lot
configuration at Well No. 3 would allow for a distance of approximately-90 feet between
the existing well and the proposed well considering Minnesota Department of Health '
property boundary requirements. These requirements call for a municipal well to be
located at least 50 feet from the nearest property boundary such that the minimum lot
size must be slightly larger than 100 by 100 feet for an individual well. The preferred
separation distance for these wells, which will be finished in the same aquifer, would be
more on the order of 300 to 500 feet. The availability of lend within this general distance
should be examined at the earliest convenience as the next step in developing proposed I
well no. 6.
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IL PROJECT SCHEDULE
With the intent of providing an additional water supply source to Chanhassen in the
summer of 1990, the following schedule should be implemented. The schedule for the drift
well is very aggressive but should be achievable with cooperation between Liesch
Associates and the City staff.
Drift Well
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Submit preliminary report to City December 22, 1989
Submit specifications for test well to City December 29, 1989
City approval of report and specifications January 8, 1990
rAdvertise for bids - test well January 12, 1990
Bid opening - test well January 22, 1990
1 Award contract - test well January 22, 1990
1 Complete test drilling - submit report March 2, 1990
Submit plans and specifications to city -
S Production Well #6 March 8, 1990
1 City approval of plans and specifications March 12, 1990
Advertise for bids - production well March 16, 1990
' Bid opening - production well April 5, 1990
Award contract - production well April 9, 1990
Complete construction - production well -June 15, 1990
Prairie du Chien Well
City acquires land for well March 1, 1990
Submit plans and specifications to City 4, 1990•
City approval of plans and specifications April 9, 1990
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Advertise for bids April 13, 1990
Bid opening May 10, 1990
Award contract
May 14, 1990
Complete construction November 15, 1990
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ESTIMATED COST I
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A construction cost estimate for construction of these two wells was previously submitted '
to the City. The costs presented in that estimate still represent a reasonable estimate.
•We have attached that estimate at the end of this report. The estimate should be revised I
when a site for Well No. 6 is selected.
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CONSTRUCTION COST ESTIMATE
NEW WELLS
CITY OF CHANHASSEN
1 ) Construct new Prairie du Chien
Well at Pumphouse 3 - 1000 to 1500 gpm
Construct New Well - 16" diameter, 450 ' deep $200,000
New Well Pump - 200 hp $ 35,000
10" Watermain Well to Pumphouse $ 55,000
Modifications to Pumphouse $ 25,000
Electrical Power & Controls $ 40,000
Replace Existing Pump #3 $ 35,000
Remove Booster Pump S 5,000
ESTIMATED COST $395,000
NOTE: Cost does not include land acquisition.
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2 ) Construct New Drift Well at Pumphouse 2
500 gpm Construct Test Well $ 20,000
Construct New Well - 12" diameter $ 80,000
Well Pump $ 10,000
11 Watermain $ 10,000
Modifications to pumphouse $ 15,000
Electrical Power & Controls $ 20.000
ESTIMATED COST $155,000
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200,000 GALLON WATER TOWER
HIGH WATER LEVEL=EL1200
SCHOOL •
250 GPM LL I
GATE VALVE
NORMALLY CLOSED
PRESSURE REDUCING VALVE
HI e73th I E.AREA _
PRESSURE REDUCING
VALVE
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1,500,000 GALLON STORAGE TANK
STATIC PRESSURE=91 psi HIGH WATER LEVEL=E .1120
PRESSURE REDUCING •
BOOSTER PUMP VALVES
1000 GPM • 5t .� NORMALLY CLOSED „'
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STATIC PRESSURE=57 psi 0 18' T<RUH>-MAIN
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LAKE
MI A ASHTA
SERVICE AREA 1111111111111.111111
APPROX. WATER LEVEL=EL1150 IIIIMIIIIMIIEII
Ell11.1.11.1111
t 100,000 GALLON • ' REA
WATER TOWER I
HIGH WATER LEVEL=EL.1120
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WELL NO.3
1000 GPM
! f �.�. t WELL NO.2
STATIC PRESSURE= �1111�� 0 1000 GPM
• 50 PSI--It •iii .
< i ,..% , PROPOSED
BOOSTER - '� WELL NO.5
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500 GPM
PROPOSED WELL NO.6 ST TI PRESSURE=68 psi
1000 GPM
I WELL NO.4
• 975 GPM
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I BRUCE A LIESCH ASSOCIATES.INC. CHANHASSEN, MINNESOTA
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SCHEMATIC MUNICIPAL WATER SYSTEM
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PROJECT SCHEDULE
With the intent of providing an additional water supply source to Chanhassen in the
summer of 1990, the following schedule should be implemented. The schedule for 8 p o the drift
well is very aggressive but should be achievable with cooperation between Liesch
Associates and the City staff.
Drift Well >
Submit preliminary report to City • December 22, 1989 •
Submit specifications for test well to City December 29, 1989
City approval of report and specifications January 8, 1990
Advertise for bids - test well January 12, 1990
Bid opening - test well January 22, 1990
Award contract - test well January 22, 1990
Complete test drilling - submit report March 2, 1990
Submit plans and specifications to city -
Production Well #6 March 8, 1990
City approval of plans and specifications March 12, 1990
Advertise for bids - production well March 16, 1990
Bid opening - production well April 5, 1990
Award contract - production well April 9, 1990
Complete construction - production well -June 15, 1990 •
Prairie du Chien Well
City acquires land for well March 1, 1990
Submit plans and specifications to City • April 4, 1990
City approval of plans and specifications April 9, 1990
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Advertise for bids April 13, 1990 : I
Bid opening May 10, 1990
Award contract May 14, 1990 1
c Complete construction November 15, 1990
• ESTIMATED COST
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A construction cost estimate for construction of these two wells was previously submitted
to the City. The costs presented in that estimate still represent a reasonable estimate.
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We have attached that estimate at the end of this report. The estimate should be revised
when a site for Well No. 6 is selected.
R48:1219CHAN
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