1c. Plans & Specs for City Wells 5 & 6 CITY T
. , CHANHASSEN
690 COULTER DRIVE • P.O. BOX 147 • CHANHASSEN, MINNESOTA 55317
(612) 937-1900 • FAX (612) 937-5739
MEMORANDUM
11 TO: Don Ashworth, City Manager
' FROM: Gary Warren, City Engineer -
DATE: November 15, 1989
' SUBJ: Authorize Preparation of Plans and Specifications for
Construction of Wells No. 5 and 6
Project No. 89-4
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This item was before the City Council at the last meeting,
November 6, 1989 , and was tabled at the request of Councilman
Johnson in order to clarify "inconsistencies" which he felt were
present in the proposal . I spoke with Councilman Johnson after
the City Council meeting and he explained that he did not
understand how we could put two wells in one wellhouse as is our
intention for both Well 5 and 6 proposals . I clarified that the
wells themselves would actually be sunk in a location outside of
' the wellhouse in an area beyond the "zone of influence" for the
existing wells. This would be determined by our hydrogeologist
during the design. Submersible pumps would then be utilized to
pump the ground water through discharge piping into the existing
wellhouse thereby taking advantage of the existing treatment
facilities that are available in the welihouses as well as the
distribution headers, etc. The City stands to save close to
$100 ,000 in new wellhouse construction costs by proceeding in
this fashion.
' With this concern satisfied, the item is once again placed before
the Council for authorization of preparation of plans and speci-
fications. I believe the two well approach is prudent as
discussed in my November 2, 1989 staff report tattached) . The
glacial drift well which has a .-bit more uncertainty and risk
involved with its development,- also has the most potential for
providing the cheapest water to the City in the shortest amount
' of time. If we proceed forward at this time with preparation of
construction documents and proceed with test drilling during the
winter months, it is very feasible that the City could indeed
have an additional 500 gallons per minute of well capacity on
line by the spring of 1990 . As shown in the attached table, if
we are successful in adding 500 gallons per minute to the system
' capacity in this fashion, we would basically match the system
demand including fire storage estimated for 1990 .
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Don Ashworth
November 15, 1989
Page 2
In order to keep pace with the rapid development, especially with
the potential expansion in the works for the MUSA area, it would
be advisable at this time to also pursue the development of the
deep aquifer Prairie du Chien-Jordan well. If we are able to
achieve an additional 1, 200 gallons per minute from the Prairie
du Chien well, this would roughly provide the City with enough
well and storage capacity to the year 1997.
It is therefore recommended that the City Council proceed with
the approach as recommended in the November 2, 1989 staff report
' and authorize the preparation of plans and specifications for
construction of Well No. 5 and 6 .
' Attachments
' 1. Water system pumping demand and storage requirement table.
2 . November 2, 1989 staff report with attachments.
c: Jim deLambert, B. A. Liesch & Associates
Manager' s Comments
' Funding to accomplish the recommendation being made by the
engineer could be accomplished through a combination of bonding
and cash on hand. The water availability fund should have an
unallocated fund balance at year end of approximately $350,000.
The sewer availability fund will have a much stronger balance,
i .e. approximately $600, 000. Although these funds were
established as separate funds, they jointly provide capital
monies for the one common enterprise activity - utility opera-
tions . The commonality of these funds can also be seen by the
' City' s decision to fund both the groundwater storage facility
(new water tower) as well as Lake Ann Interceptor extension via
bond issues supported almost entirely by general obligation
receipts. Having either of these facilities paid for solely by
either the water availability fund or sewer availability fund
would have bankrupted either or both these sources of funds. The
point being that the City has previously looked at capital expen-
ditures in terms of how best to accomplish the job, not whether
sewer operations had precedent over water operations or vice-
versa. Both funds currently receive approximately $100,000 per
year in revenue with forecasted expenditures currently being at
approximately $50,000 per year. The utility fund itself may also
be able to contribute to debt payments such not being the most
desirous option in that the City has been attempting to increase
the fund balance of the enterprise fund - a goal which has only
recently been achieved.
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Manager' s Comment Continued
Page 3
This office would recommend that the City Council authorize staff
to seek advice from our financial advisors, Springsted, Inc. , and
to have their report at the time that the City Council would con-
sider accepting the plans and specifications and authorizing the
taking of bids. Again, I feel confident that the Springsted
recommendation will be positive in terms of the City' s ability to
fund the proposed expenditures. The primary issue is really one
of what sources of funds should be used in accomplishing that
end. Approval of the engineer' s recommendation with the con-
dition that Springsted prepare a report on alternative financing
prior to resubmitting this item is recommended.
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WATER SYSTEM PUMPING DEMAND
AND
STORAGE REQUIREMENTS
' 1990 2000
5. 0 MG* Average Maximum Day Demand Projection 7.1 MG*
4 . 5 MG 90% of Maximum Day in 16 Hour Requirement 6.4 MG
-3. 3 MGt System Pumping Capacity in 16 Hours 4.5 MG#f
' 1. 2 MG Usage-Storage Requirements 1. 9 MG
+0. 6 MG Fire Demand Reserve +0 .6 MG
' 1. 8 MG Total Storage Required 2. 5 MG
1 . 8 MG Storage Available 1. 8 MG
0 .0 MG Deficiency 0 . 7 MG
NOTE: 6. 3 MG is maximum average day tolerable with 4 .5 MG
pumping capacity which correlates to the 1997 average
maximum day demand projection without additional storage.
*Source 1985 Water System Analysis Report
f = 300 GPM existing + 500 GPM drift well addition.
tt = 300 GPM existing + 500 GPM drift well addition + 1200 GPM
Prairie du Chien-Jordan well.
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4 tfyi , CITY
tior
690 COULTER DRIVE • P.O. BOX 147• CHANHASSEN, MINNESOTA 65317 II(612) 937-1900 • FAX (612) 937-5739
MEMORANDUM I
TO: Don Ashworth, City Manager
FROM: Gary Warren, City Engineer I
DATE: November 2, 1989 1
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SUBJ: Authorize Preparation of Plans and Specifications for ;
Construction of Well No. 5 and 6
Project No. 89-4 I
As will be recalled, the City Council commissioned Bruce A.
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Liesch Associates, Inc. to prepare a feasibility study to
investigate the siting of wells in the City and, in addition, to
review the feasibility of expanding the capacity of our existing II wells 2 and 3. This draft report was completed and accepted by
the Council earlier this year. This led to to a recommendation
to perform test pumping on wells 2 and 3 to further evaluate II their capacity for expansion. This was recently completed and
the attached addendum report prepared by Bruce A. Liesch
Associates, Inc. summarizes the findings and further defines the
City's options. i
Subsequent to the preparation of this addendum report, a centri-
fugal sand tester was installed on pump discharge headers to II wells 2 and 3 to identify the sand content of the discharge.
Unfortunately, the sand testing results were disappointing in
that well 3 showed an inordinate amount of sand is being deve-
loped from the well. It is difficult to say if this is a charac- '
teristic of the Prairie du Chien-Jordan aquifer or strictly
representative of the way that the well was developed. In either
case, this has precluded pursuing the less-costly option of II expanding existing well 3 by adding a higher capacity pump.
Review of the well log and pump tests conducted at well No. 2 at II South Lotus Lake have revealed that potential exists for sinking
a glacial drift well at well house No. 2. There are a few more
preliminary steps involved in the process and more risk since the
gravel strata is less predictable than the deeper bedrock wells;
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however, the construction cost savings are also significant, i .e.
$155,000 versus $395,000. The City of Maple Grove, for example,
has a number of "drift" wells. Due to the system hydraulics, 11 i .e. distribution piping constraints, we could add approximately
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Don Ashworth
November 2, 1989
Page 2
1 400 to 500 gpm to the City' s pumping capacity by spring of 1990
if this option were pursued and everything worked out.
This step still is an interim measure in that the City ' s 1985
water study anticipated adding another major bedrock well (1000
to 1500 gpm) into the system by 1992. Since this can be a
lengthy process, construction should be in 1990.
It has not been decided at this point where the exact location of
' the bedrock well will be and this will be a part of the prelimi-
nary investigations of the design effort. The construction cost
of a new bedrock well is estimated to be $395 ,000 assuming the
new well can be integrated into one of our existing well houses.
This would be hammered out early on in the design effort as noted
in the attached scope of services supplied by Bruce A. Liesch
Associates, Inc. The specific design recommendations and esti-
mated construction cost would then be presented to the Council
for further authorization.
Expenditures of this magnitude would exceed the City ' s Water
Expansion Fund balance ($317 ,000 ) . It also would appear more
appropriate, since the additional capacity is necessary to meet
recent and anticipated future growth of the City, that these
' improvements be bonded for and paid back over a period of time
from future trunk funds. It is therefore recommended that
financing for these improvements be accomplished with the sale of
a revenue bond issue with proceeds from the Water Expansion Fund
( 402 ) pledged to pay off the bonds over a period of years.
' A two-pronged approach is therefore recommended for meeting the
City 's water system needs:
1. Authorize commencing with necessary investigations and engi-
neering for constructing a glacial drift well at well house
No. 2 at South Lotus Lake; estimated design service $13, 960 .
2. Authorize commencing with the design of a bedrock (Prairie du
Chien) well at pump house No. 3; estimated design services
$21,360.
It is recommended that the firm of Bruce A. Liesch Associates,
Inc . be directed to perform this work for the City in accordance
with their attached scope of services dated November 2, 1989.
Attachments
1. Generalized cost comparisons for water supply options.
2. Proposal for design services dated November 2, 1989.
c: Hal Summitt, Bruce A. Liesch Associates, Inc.
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Manager's Comments: Funding options should be reviewed by
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the City's financial advisor.
DWA (11-2-89)
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':. ;' �► BRUCE A. LIESCH ASSOCIATES, INC.
HYDROGEOLOGISTS • ENGINEERS • ENVIRONMENTAL SCIENTISTS
3020 Harbor Lane•Minneapolis,MN 55447.612-559-1423•FAX No:559-2202
City of Chanhassen
Generalized Cost Comparison for Water Supply Options
' Based on discussions with the Chanhassen Engineering Department
subsequent to review of our draft "Preliminary Water Supply
' Investigation" , Bruce A. Liesch Associates, Inc. has prepared this
summary of development options. The summary includes a brief
discussion of each option and estimated range of costs.
I. INCREASE CAPACITY OF EXISTING WELL
This may be an option at existing Prairie du Chien-Jordan wells
(Wells 2 and 3) . The results of pumping tests conducted at these
wells suggest additional capacity is available based on calculated
' aquifer coefficients and observed well yield. However, information
collected subsequent to the pumping tests suggests the possibility
' for sand pumping at higher rates. This possibility should be
further assessed prior to making permanent improvements to either
well.
Pump performance curves and development details have been reviewed
for Well 3 and reveal that some problems were encountered during
well development. Apparently the lower portion of the open
' borehole at Well 3, which was open to the Jordan Sandstone
Formation, was backfilled with "pea rock" in an attempt to reduce
' sand pumping. The records do not clearly indicate the sequence of
events. However it appears as though the sandstone portion of the
borehole was blasted with dynamite and bailed out during the period
from February 22 to March 6, 1973. A test pump was then installed
in the well and operated at rates ranging from 550 to 1739 gpm
while producing excessive amounts of sand. Then the test pump was
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apparently pulled from the well and again blasted with dynamite in 11
the upper portion of the open borehole on April 6 and 10, 1973.
The well depth was reported at 390 feet during the second round of
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blasting rather than the original depth of 500 feet. A diag'ram .of
the well which shows "pea rock" backfill from 370 to 500 feet Vks
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included in the driller's well report. Test pumping continued from
April 16 to May 16, 1973 at rates ranging from 200 to 1900 gpm. I
During this period the specific capacity of the well appeared to
increase with continued pumping and removal of sand.
With Prairie Du Chien-Jordan wells water enters the borehole from
both formations. The Prairie Du Chien formation consists primarily , 1
of dolomitic limestone through which water moves in fractures and
crevices. The Jordan is a sandstone formation where water moves
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through porespaces between individual grains. The percent of well
yield which may be attributed to each formation will vary with II fracturing in the dolomite and permeability of the sandstone.
The propensity for sand pumping will depend on the degree of I
cementation within the sandstone, grain size and the velocity of
water moving through the well. The only factor that can easily be
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controlled is, of course, the velocity of water by adjusting the
pumping rate. i
Inasmuch as the sandstone portion of the borehole at Well 3 has II been filled with pea rock we would anticipate reduced yield from
the sandstone along with increased entrance velocity in the
remaining, open portion of the borehole. I
The available data does not clearly indicate at what rate does sand
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pumping occur. This should be examined prior to making well
improvements. Our review of the existing pump data suggests that
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the pumping rate of Well 3 could be increased to approximately 1250
gpm pumping to a nearby hydrant rather than into the system under II normal system pressure. If this can be arranged a centrifugal sand
tester could be installed on the pump discharge line to measure
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sand content at the higher rate. For testing beyond about 1250 gpm
11 it will be necessary to remove the existing pump and temporarily
install and operate a higher capacity test pump.
Pumping the well with existin g pump to waste (hydrant) and
installation of a sand tester could be accomplished by the City.
Some additional costs for oversight of the pumping procedure and
' analysis of sand pumping data could be anticipated and should not
exceed approximately $2,000.00.
' If a test at a higher rate is warranted a drilling contractor would
be required. Removal of the existing pump: installation, operation
and removal of a test pump; and reinstallation of the original pump
would cost on the order of $10,000 to $12,000, with an additional
' cost of approximately $3,000 for oversight and analysis of the
data.
If additional capacity is available, pump sizing, purchase and
installation could be anticipated on the order of $40,000 to
' $60,000 for a 1600 gpm vertical turbine or submersible
installation.
II. BEDROCK NELL
The preliminary report indicates that a Prairie du Chien-Jordan
well could be developed in the northeastern portion of the City
and a Mount Simon-Hinckley well over a larger area. Hore
information is available regarding the Prairie du Chien-Jordan
' aquifer and well construction and yields would be similar to the
existing City Wells 2 and 3. Costs could be anticipated as
' follows:
' Well and Pump: $250,000.00
Pumphouse and Controls: $100,000.00
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Pitless adapter in combination with
existing well house $ 30,000. 00
Engineering/design/inspection and
testing $ 50,000. 00
Pump house and engineering costs would be similar for a Mount
Simon-Hinckley installation with the well and pump perhaps costing
an additional $50,000.00. Note that at present the Minnesota '
Department of Natural Resources appears to be discouraging
development of this aquifer where other options are available. The
feasibility of a Mount Simon-Hinckley well, from a permitting
standpoint, should be examined if this option is seriously
considered. I
III. GLACIAL DRIFT NELL '
As stated in the preliminary report, this option may require an
investigation phase to locate a suitable site and to verify well
yield, design and water quality. Owing to the many uncertainties
associated with drift aquifer it is extremely difficult to even
"ball park" total project costs. Depending on the general area
chosen for investigation a geophysical investigation may be
warranted. In any case, a test drilling and aquifer testing
program would be advisable in an area without existing high
capacity drift wells. Site investigation costs including
contractor costs, water quality analysis and professional fees
could range from $30,000 to $50,000. If favorable aquifer
conditions are encountered well and pump costs for a 300 foot
glacial drift well producing 1000 gpa may range from $120,000 to
$160,000. Pumphouse and control costs would be similar to those
for a bedrock well. Inspection and testing costs may be lower
owing to anticipated shorter construction time.
Sincerely,
� r
mes de Lambert
ydrogeologist R44,COST1024
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�gl4: BRUCE A. LIESCH ASSOCIATES, INC.
HYDROGEOLOGISTS • ENGINEERS • ENVIRONMENTAL SCIENTISTS
3020 Harbor Lane•Minneapolis,MN 55447.612-559-1423•FAX No:559-2202
November 2, 1989
Hr. Gary Warren
City Engineer
City of Chanhassen
' P.O. Box 147
Chanhassen, HN 55317
RE: Proposal for Design Services for New Wells
' Dear Hr. Warren:
' We are pleased to submit the attached proposal for design and
construction services for construction of new wells in Chanhassen.
We have broken the costs down into two projects; construction of
' a Prairie du Chien well at pumphouse 3 and construction of a well
at pumphouse 2. As you are aware, these costs are roughly
estimated at this time and can be refined depending on the location
of the wells.
. I As always, we propose to bill our services at hourly rates for time
actually spent on the project. Therefore, we anticipate the actual
' costs to be less.
If you have any questions, please contact us.
ncerely,
F
0.AAA.AA
Ja as Bullert, P.E.
Bruce A. Liesch Associates, Inc.
JB/ms
R44:CHAN11-2
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SCOPE OF SERVICES
WELL DESIGN
CHANHASSEN, MINNESOTA
SERVICES MILL INCLUDE:
1. An evaluation of optional locations for the new wells '
(pumphouse 2, pumphouse 3 or other) considering aquifer
conditions, water main hydraulics and existing pumphouse
configuration.
2. Preparation of plans for a new bedrock well at pumphouse 3 and
a new drift well at pumphouse 2, detailing: '
o watermain piping from well to pumphouse and pumphouse to
street, if necessary.
o piping revisions in pumphouses
o revisions to chlorination and fluoridation systems '
3. Preparation of specifications detailing:
o well construction for two wells I
o piping
o valves
o chlorination and dechlorination systems U
o electrical service and controls - both wells
Services not included and considered extra if required:
o Design of new pumphouse or addition to existing pumphouse '
o Major watermain design (over 700 feet)
o Services related to land acquisition
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IIESTIMATED ENGINEERING FEES
1) New Prairie du Chien Well at puaphouse 3
IIDesign Services
I Aerial Photography & Site Survey $ 1,000
Evaluation of Optional Locations
Sr. Engineer 60 Hours ! $75 $ 4,500
Site & Watersain Plan
I Sr. Engineer 16 Hours ! $75 $ 1,200
Jr. Engineer 40 Hours @ $50 $ 2,000
Piping & Construction Details
I Jr. Engineer 40 Hours ! $50 $ 2,000
Prepare Specifications
Sr. Engineer 40 Hours ! $75 $ 3,000
I Clerical 24 Hours ! $24 $ 576
Well Design
Hydrogeologist 40 Hours ! $75 $ 3,000
Clerical 16 Hours I $24 $ 384
I Electrical Engineering
(Exe. Assoc. - Consultant)
Subcontract $ 3,000
IMiscellaneous Mileage, Materials, Etc. S 700
$21, 360
IConstruction Services
Project Bidding
I Sr. Engineer 60 Hours ! $75 $ 4,500
Construction Management
Sr. Engineer 120 Hour $75 $ 9,000
Jr. Engineer 40 Hour $50 $ 2,000
Shop Drawings Review/Hydraulic Review
Sr. Engineer 40 Hours ! $75 $ 3,000
II Project Inspection
Sr. Engineer 60 Hours ! $75 $ 4,500
Field Inspector 150 Hours ! $50 $ 7,500
Start Up/Checkout/Operator Training
I Sr. Engineer 16 Hours ! $75 $ 1,200
Electrical Engineer (Exe. Assoc. ) $ 1,500
Well Construction Observation
I Sr. Hydrologist 100 Hours ! $75 $ 7,500
Jr. Hydrologist 150 Hours ! $50 $ 7.500
I $48,200
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2) New Drift Well at Pumphouse 2 1
Design Services
Site & Watermain Plan
Sr. Engineer 8 Hours E $75 $ 600
Jr. Engineer 40 Hours 0 $50 $ 2,000
Piping & Construction Details
Jr. Engineer 24 Hours 0 $50 $ 1,200
Prepare Specifications
Sr. Engineer 40 Hours I $75 $ 3,000
Clerical 24 Hours I $24 $ 576
Well Design
Hydrogeologist 40 Hours I $75 $ 3,000
Clerical 16 Hours I $24 $ 384 '
Electrical Engineering
(Exe Assoc. -Consultant) $ 2,500
Miscellaneous Mileage, Materials,etc. S 700 '
$13,960
Construction Services I
Project Bidding
Sr. Engineer 60 Hours 0 $75 $ 4,500
Construction Management
Sr. Engineer 80 Hours I $75 $ 6,000
Jr. Engineer 40 Hours E $50 $ 2,000
Shop Drawing Review
Sr. Engineer 40 Hours I $75 $ 3,000
Project Inspection
Sr. Engineer 60 Hours I $75 $ 4,500
Field Inspector 80 Hours ! $50 $ 4,000
Start-up/Checkout/Operator Training
Sr. Engineer 16 Hours I $75 $ 1,200
Electrical Engineer (Exe. Associate) $ 1,000
Test Well Observation & Evaluation
Sr. Hydrogeologist 40 Hours I $75 $ 3,000
Jr. Hydrogeologist 60 Hours 0 $50 $ 3,000
Production Well Construction Observation
Sr. Hydrogeologist 40 Hours I $75 $ 3,000
Jr. Hydrogeologist 80 Hours 0 $50 $ 4.000 '
$39,200
TOTAL ENGINEERING PEES: $122,720 I
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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 43 $ 35,000
' Remove Booster Pump S 5.001)
ESTIMATED COST $395,000 '
NOTE: Cost does not include land acquisition.
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
Watermain S 10,000
' Modifications to pumphouse $ 15,000
Electrical Power & Controls L S 20.000
ESTIMATED COST $155,000
' R44:CHAN
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