20041102Application.pdf

JAMES A. SEWELL & ASSOCIATES
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Consulting Engineers
~okane Office
Electrical & Civil Engineering
9 South Washington Street, Suite 708
Spokane, Washington 99201-3718
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Building Inspection
Pend Oreille Professional Center
30336 Highway 200, Suite C
Sand point, Idaho 83864
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Civil Engineering .Land Surveying.
Building Inspection
600 4th Street West
Newport, Washington 99156
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Civil Engineering. Electrical Engineering. Land Surveying. Building Inspection
October 27 2004 C:\ajmo I \Projects\SR\HVR\Phase II\wefi~UC W€1!'1#2 report:OCk
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Idaho Public Utility Commission
472 W Washington
O. Box 83720
Boise, Idaho 83720-0074
Attn: Jean Jewell
Commission Secretary
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SUBJECT:Stoneridge Utilities
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Dear Commissioners:
CDS Stoneridge Utilities is proposing that the loan from DEQ for interconnecting the drinking water
systems of Happy Valley Ranchos (HVR) and Stoneridge be increased to cover additional costs for
improving the reliability of the combined system. The previous loan amount (approved 6/23/04) was
$359 297 and the estimated revised cost for completing the same scope of work previously approved is
now $428 500. The majority of the cost increase is for constructing a new well to replace Well #2.
the June 2004 budget, the plan was to rehabilitate the existing well so that it could continue providing
600 gpm. After investigating this alternative thoroughly, it was found that the well could not be
rehabilitated to provide an adequate supply. The new plan is to drill a new well that will provide
enough flow to match what previously was provided by Well #2 (600 gpm).
Background
In correspondence this last June, which was submitted to the IPUC as part of the support
documentation for the Phase II work, the IDEQ has told Stoneridge Utilities that the utility must have
automatic backup of the source pumps. Since that time Stoneridge Utilities has found that the work
needed to complete the project was greater than originally anticipated. Originally the plan called for
the replacement of the pump in well no. 2; since that time it has been determined that well no. 2 must
also be replaced.
The preliminary investigation of methods to rehabilitate Well #2 has been completed and various
options studied. Originally, Well # 2 was capable of pumping 600 gpm at a TDH of 420 feet.
The line shaft pump in Well #2 has not worked correctly for many years. The motor would heat up
quickly and could only be operated in the manual mode with a full time operator present. Phase 2 of
this Stoneridge/HVR Project was to replace the pump, motor and starter panel. When the contractor
tried to pull the pump with the derrick mounted on a pick frame, the pump became lodged and could
Happy Valley Ranchos, Phase II
October 27 2004
Page 2 of 6
not be removed. A large crane was brought in and the pump was successfully removed. A TV camera
was brought in to determine why the pump became lodged in the well. The camera showed the water
table at 91 feet down. At 108 feet down the remains of the original plastic screen were found wedged
in the well, within the 10 inch casing.
The original well had been drilled to 144 feet with a plastic screen set between 144 and 124 feet, and
the 10 inch casing had been pulled back to approximately 124 feet. Some time before the pump was
set last time; the screen had been hooked and pulled up in the well. When the pump was last set in the
well, the screen became lodged at the 108 foot level. The well has probably collapsed below the
bottom of the casing at 124 feet.
The normal way to repair the well would be to advance a new 8-inch casing inside the existing 10-inch
casing. In this manner, the well would be dug back to its original 144 feet depth. The well would be
dug utilizing a new 8-inch casing inside the existing 10-inch casing. The casing would be advanced to
the bottom of the well at 144 feet. Then a 20 foot long telescoping stainless well screen would be set at
the bottom of the well and the 8 inch casing withdrawn to an elevation of about 124 feet. A
submersible pump and motor would be set inside the well casing, with the pump intake just inside the
bottom of the casing. The 8-inch diameter of the well casing limits the size of pump and motor that
can be installed in the well. In the case of the 8-inch casing, the motor would need to be less than 7
inches in diameter. The maximum pump and motor that would meet these criteria would be a 60
horsepower motor coupled to a pump that would discharge 415 gpm at 420 feet of head.
Options
This first option was rejected because it reduced the dependable system capacity below what is
necessary to assure the customers of Stoneridge Utilities an uninterruptible supply of water. The May
, 2003 engineering report contains calculations pertaining to the required capacity of the sources of
supply to the water system. Appendix 7 of the report calculated that the Average Daily Demand
(ADD) for the design of710 Equivalent Residential Users (ERU) was 527 gpm. At that time the sum
of all the pumping capacity of all sources less the capacity of the single largest source was 600 gpm.
(The two sources were 600 and 800 gpm).
This calculation shows that the system could easily continue to provide the normal ( average) amounts
of water necessary to the residential customers with the largest well out of service. If the rated supply
of water to the system to serve the normal demands is less than 527 gpm, then additional sources are
going to need to be developed. This criterion is used because the ADD is the normal demand on the
system which can be expected at all times. The loss of the use of a pumping source is to be expected at
anytime, though hopefully it will not occur. The failure could be to any of the pumps, so to be
conservative; it is assume to occur to the single largest pumping source. Such a failure is normal and
should be planned for to limit the disruption of service to the water system customers.
A second option would be to install the screen similar to the first option above, then the 8-inch casing
would be completely removed, and a packer (a device to seal between the 7.inch screen and 10-inch
casing) would be advanced on the end of the drill rod and then screwed onto the new screen at a depth
of 124 feet. Attaching the large packer to the screen is not guaranteed to work and could end up
destroying the screen and not seal the well. If the method of developing the well were successful, then
a larger pump and motor could be installed in the sell. With the larger well casing, the maximum size
pump and motor would be capable of discharging 600 gpm at a TDH of 420 feet. This pumping rate is
nearly equal to the hydraulic capacity of the new screen, thus maximizing the yield of the well.
Licensed in Washington, Idaho, & Montana
Happy Valley Ranchos, Phase II
October 27 2004
Page 3 of 6
The third alternative is to drill a new well in the same well field. The new well would be sized to
produce as much as the other source well (800 gpm). This well would have a 16-inch casing, with a
125 horsepower submersible motor driving a pump capable of discharging 825 gpm at a TDH of 420
feet. The existing 10-inch well would be turned over to the golf course and at some future date
Stoneridge could repair the well. The estimated 400 gpm from this rehabilitated well would meet
about 80% of the average irrigation demand. If the golf course did not want the well, it could be
abandoned at a cost of about $5 000.
A fourth option is to use the existing Well No., utilize the rehabilitated Well No.2 (the 8-inch well
option) and drill a third 8-inch well. The total pumping capacity of the three wells in Option 4 would
be 1 630 gpm (Well No.1 = 800 gpm, Well No.2 = 415 gpm, and Well No.3 = 415 gpm) and the
water supply available to supply the system with the single largest well out of commission would be
830 gpm, more than the 527 gpm required to provide for the normal usage of all the residential
customers.
A fifth option is drilling a new 10" well to provide about 600 gpm. This would provide an adequate
second source for most situations based on the recommendations in the May 2003 engineering report.
There is a cost savings of $ 27 000 over the cost of constructing a new 16-inch well and the supply
should be adequate for the 20-year design.
The table below summarizes the various options and estimates the cost of each option:
Well # 2 Well # 1
Rehab.Rehab.New
Existing Existing Well New
Item Units well Well Well
Casing Diameter inches
Screen Length feet
Screen Diameter inches
Screen opening inches
Screen Capacity ~0.34.
fps gpmlft 26.26.42.
Screen capacity gpml20 ft 539 539 683 854
Pump TDH 420 420 420 420 420
Pump rating gpm 415 600 600 825 800
Pump diameter inches
Pump Power 125 125
Cost of well drilling 000 000 $28 000 $ 50 000
Cost of pump $ 25 571 000 $30 000 $ 35 015
Cost of structure $10 000
wiring 000 000 $ 10 000
Contingency
Total Cost $ 40 571 000 $68 000 $ 95 015
The first option reduces the capacity of the smallest well supplying the Stoneridge system, effectively
reducing the system source from 600 gpm to 400 gpm. The second option preserves the current system
Licensed in Washington, Idaho, & Montana
Happy Valley Ranchos, Phase II
October 27, 2004
Page 4 of 6
capacity, but carries significant risks that it cannot be successfully completed and would incur
considerable expense as well as still requiring that a new well be drilled. The third option would
increase the system source supply from 600 gpm to 800 gpm. The fourth option would provide more
capacity than required to serve the 20-year design population and the cost will be comparable to the
cost for the new 16-inch well (Option 4).
It is recommended that Stoneridge proceed with the fifth option, the construction of a new 10" well and
installation of a 600 gpm pump if the funds can be found to finance this cost. The next best option is to
proceed with the first option. This would require the least money now, but would require that a third
well be developed in the near future, or the capacity of the water system would be reduced by 33% and
potentially causing the water system to restrict full delivery to all the current customers when the
largest pump was out of service.
Revised Proi ect Costs
The original HVR project as described in the May 8 2003 report had an estimated budget cost of
$213,450. Construction is nearly completed on that project (Phase I) and the final budget is $275 000.
The Phase I improvements are to serve the HVR customers only. These increases are due to extra costs
associated with Right of Way acquisition, exact location of the pipes, and increased lengths of some of
the parts of the system.
During construction of Phase I, DEQ instructed Stoneridge Utilities to increase the reliability of the
controls serving both the HVR portion of the system and the SU source pumps. The estimated cost of
these changes is $153 500. The Phase II work will increase the combined budgets ofHVR and SU
13%.
The Phase II work, as currently budgeted, includes repair of Well #2 and installation of automatic
controls for cycling the pumps and sending alarms to the operator. The construction of the automatic
controls has been completed and the exact cost is shown in the table below. The cost of completing the
construction of the new well and pumping facility is itemized in the table below, as is the engineering
and contingency allowance.
Licensed in Washington, Idaho, & Montana
Happy Valley Ranchos, Phase II
October 27 2004
Page 5 of 6
A comparison to the June 2004 budget is also provided.
June 2004 Costs October 2004 Costs
Phase $268 097 $275 000
Phase II
Automatic Controls $38 000 $46 455
Well No.2 pump removal 840
New well construction $28 000
New 600 gpm pump $30 000
Pump house $10 000
Replacement of existing pump $26 000
Contingency 600 600
Engineering original $17 600 $17 600
Engineering additional 000
Total cost of Phase II $91 200 $153 500
Total Cost for Ph. I & Ph. II $359,296 $428,500
Life of Loan 20 years 20 years
Interest rate 2 %
Phase I Annual Payment $16,400 $16 820
Phase II Annual Payment 580 390
Total Annual Payment $21 980 $26 210
The IPUC in Order No. 29507 dated May 28, 2004, has recommended that the costs of the Phase II
improvements should be born by all the users in the combined system. The cost of these improvements
would be financed with an increase in the state loan that is financing the construction of the
Stoneridge/Happy Valley Ranchos Water System Interconnection. This loan is by the State Revolving
Fund (SRF) administered through the Idaho Department of Environmental Quality (IDEQ). The terms
of the loan are 2% for 20 years. The annual repayment for this portion of the loan would be about
500 per year.
The updated user costs for a typical customer using 6 000 gallons of water per month are estimated
below. The rates are set by the IPUC and so it is not possible to say with assurance how the IPUC will
allocate the costs to the various users classes. For this estimate, it is assumed that the Phase I costs are
born by the HVR customers only through a surcharge on the base rate and Phase II costs are to be born
by all the customers on the combined system. Assuming that the IPUC spreads the costs out uniformly
among all the customers, the increase will be the same percentage for all customers; i.e. a Stoneridge
homeowner would see a $15.80 monthly charge increased to $17.81 and a commercial account would
see a $5 000 monthly charge increased to $5 636.
Licensed in Washington, Idaho, & Montana
Happy Valley Ranchos, Phase II
October 27 2004
Page 6 of 6
The original rates are from the May 8, 2003 report. The revised rates reflect the October 2004 budget
amounts.
Stoneridge Utility Happy Valley Ranchos
Customers Customers
original rate revised rate original rate revised rate
Base Charge 14.14.14.14.
Phase I costs 12.16.
Phase II Costs 1.78 1.78
Overage (iiJ $0.30/1000 1.80 1.80 1.80 1.80
Phase I Costs
Phase II Costs
Total $15.$17.$28.45 $34.
Stoneridge would like the input of the IPUC before proceeding with taking on the additional debt to
complete the proposed construction of a replacement for the original well no. 2.
Sincerely,
JAMES A. SEWELL AND ASSOCIATES
Consulting Engineers
. Olmstead, P ., Partner
John Tindall
Bill Jerrel, DEQ; 1410 North Hilton; Boise, Idaho 83706
WaYlle Benner
Dean Allara
Licensed in Washington, Idaho, & Montana