ACCOUNTABILITY REPORT ON VALUE ENGINEERING

FORT PECK RESERVATION RURAL WATER SYSTEM: FORT PECK ASSINIBOINE AND SIOUX RURAL WATER SYSTEM AND DRY PRAIRIE RURAL WATER SYSTEM

DECEMBER 7, 2001

FORT PECK ASSINIBOINE AND SIOUX TRIBES DRY PRAIRIE RURAL WATER TABLE OF CONTENTS

1. SUMMARY ...... 1

1.1 Sponsor Process for Evaluation ...... 1 1.2 Decisions by Sponsors ...... 2

2. DESCRIPTIONS OF DRAFT FER AND VE PROPOSALS ...... 5

2.1 Draft FER Proposals ...... 5

2.1.1 River Intake ...... 5 2.1.2 Water Treatment Plant ...... 7 2.1.3 Pipelines ...... 8 2.1.4 Pumping Stations ...... 10 2.1.5 Reservoirs ...... 11

2.2 VE Proposals ...... 12

2.2.1 Pipeline Reconfiguration with Intake and Water Treatment Plant at Poplar ...... 12 2.2.2 Pipeline Reconfiguration with Intake and Water Treatment Plant Below Fort Peck Dam ...... 13 2.2.3 Water Treatment Alternatives ...... 13 2.2.4 Chloramines ...... 15 2.2.5 Gravity Intake ...... 16

3. EVALUATION AND DISCUSSION OF VE PROPOSALS ...... 17

3.1 Proposal 1A: Revise Design Parameters and Flow Allocation in Main Pipeline System with Intake at Poplar ...... 17 3.2 Proposal 1B: Revise Design Parameters and Flow Allocation in Main Pipeline System, Change Intake to Dredge Ponds near Nashua, Account for Water Treatment Differences . . 22

3.3 Water Treatment Alternatives to Conventional: Superpulsator Clarifier with Microfiltration, Nanofiltration or Media Filtration ...... 25

3.4 Chloramines ...... 28 3.5 Gravity Intake ...... 28

4. SYNOPSIS ...... 31

ii 1. SUMMARY

This report describes the project sponsors' evaluation of and response to the value engineering study1 conducted by the Bureau of Reclamation on the Fort Peck Reservation Rural Water System, a municipal, rural and industrial water project in the northeast corner of Montana as authorized by PL 106-382 (114 Stat 1451, Oct. 27, 2000).

Sponsors of the project are the Fort Peck Assiniboine and Sioux Tribes and Dry Prairie Rural Water. The Fort Peck Assiniboine and Sioux Tribes are responsible for the planning, design, construction, operation, maintenance and replacement of the Fort Peck Assiniboine and Sioux Rural Water System within the boundaries of the Fort Peck Indian Reservation. Dry Prairie Rural Water is responsible for the Dry Prairie Rural Water System outside the Fort Peck Indian Reservation in Roosevelt, Sheridan, Daniels and parts of Valley counties in northeastern Montana. The two sponsors have participated individually and collectively in preparing the response which follows. While the two sponsors have separate areas of responsibility within the larger project (Fort Peck Reservation Rural Water System), the activities of the sponsors are integrated and cooperative.

1.1 Sponsor Process for Evaluation

The sponsors participated in a value engineering (VE) session conducted by the Bureau of Reclamation from February 25 through March 2, 2001. This participation provided a general understanding by the sponsors of the value engineering proposals as they were formulated by the VE team. When the sponsors received the VE Final Report in early May 2001, the engineer for the sponsors was directed to prepare an analysis of each value engineering proposal. The analysis was to include a recommendation to the sponsors to accept or reject each value engineering proposal based on confirmation of savings identified in the value engineering report. If a determination could not be made to accept or reject a proposal based on reconnaissance level VE cost estimating, the engineer was directed to recommend that a proposal receive further consideration when design-level investigations are undertaken.

The process resulted in a draft Accountability Report that was transmitted to the Bureau of Reclamation on June 14, 2001. The report summarizes the initial findings of the sponsors. Input was sought from the Bureau of Reclamation on the format of a final report and the nature of its content. A two-day working meeting on July 19 and 20, 2001, was attended by the Bureau of Reclamation, Bureau of Indian Affairs and the sponsor at Canyon Ferry Dam near Helena, Montana. The purpose of the meeting was to further the understanding of the requirements for the evaluation and response. Both the sponsors and Bureau of Reclamation needed to improve the understanding of the methods and assumptions used by the VE team the sponsor's engineer.

1Bureau of Reclamation, April 30, 2001, Value Engineering, Final Report, Fort Peck Assiniboine and Sioux Water Supply System, Dry Prairie Rural Water System.

1 After the Canyon Ferry meeting, the sponsor's engineer worked with Bureau of Reclamation staff and VE team members through conferencing, electronic transfer and facsimile to develop a VE response that would address the technical analysis in a manner to fully comply with the concepts advanced by the VE team. The sponsor's engineer developed spreadsheet models for reconfiguration of the main pipelines. These models expanded the hydraulic analysis from KY PipeTM by adding algorithms for computing construction, operation, maintenance and replacement costs of pipelines and pumping stations. These models were shared with Bureau of Reclamation staff and VE team members who made specific recommendations on modification of spreadsheet values and equations to insure that the intent of the VE team was properly reflected.

Similarly, agreement between the sponsors and Bureau of Reclamation was reached on construction, operation, maintenance and replacement costs of water treatment plant alternatives to insure that the intent of the VE team was properly reflected.

Both efforts were highly cooperative between the sponsors and Bureau of Reclamation. This phase of the response was concluded by letter of September 21, 2001, from the Bureau of Reclamation to the sponsors outlining the organization of a final accountability report. It was understood between the sponsors and the Bureau of Reclamation that the evaluation phase had been concluded satisfactorily and that the Accountability Report could be undertaken. This report conforms to the Bureau of Reclamation outline.

1.2 Decisions by Sponsors

Table 1 summarizes the results of the evaluation of the VE proposals. The decision of the sponsors to accept or reject VE proposals is given in Table 1. Plentywood pipeline reconfiguration, Opheim pipeline reconfiguration and disinfection with chloramines were proposals of the VE Report that were accepted. The Flaxville Road reconfiguration, Nashua intake, nano filtration and gravity intake proposals of the VE report were not accepted.

Reconfiguration design criteria (alternative 1A), such as permitting an increase in pressure from 200 to 250 psi and siting reservoirs on high points along the pipeline route are accepted by the sponsors as valid considerations for final design but with the caveat that final decisions during design will depend upon the impact of design criteria upon life-cycle costs. At this stage of preliminary design, the reconfiguration concepts have an added life-cycle cost of $9,649,035, including an increase in construction costs of $13,512,000 and a savings in annual operation, maintenance and replacement cost of $179,827. One of the primary purposes of reconfiguration was to reduce the number of pumping stations on the main transmission pipeline and on the branch lines to reduce initial pump station construction and future OMR costs. The VE proposal would decrease the number of pumping stations on the main transmission pipeline from 18 to 12. The impact of reduction of pumping stations on branch lines would be the less significant. The reduction in number of pumping stations would be achieved, however, at an additional life-cycle cost as given above. Because parts of the VE reconfiguration proposal has merit, the sponsors have chosen to "provisionally accept" the VE recommendations for reconfiguration subject to design-level costing.

2 3 Pilot testing of waters from the Missouri River will be required in design level investigations to more fully assess the value engineering proposals for conventional water treatment, micro-filtration and media filtration (VE alternatives 2A and 4A). Therefore, the sponsors have chosen to continue investigation of water treatment alternatives in design level investigations and will select among the water treatment alternatives based on more detailed life- cycle costing. Both the micro-filtration and media filtration alternatives were provisionally accepted.

All decisions of the sponsors were based on life-cycle cost information as presented in Table 1. Had the life-cycle cost of the Nashua intake alternative been equal or lower than the Poplar intake alternative, the Fort Peck Assiniboine and Sioux Tribes would have not accepted the alternative for the reason that the Tribes based their invitation to Dry Prairie and the plan for development of a regional system on an intake and water treatment plant located on the Fort Peck Indian Reservation

4 2. DESCRIPTION OF DRAFT FER AND VE PROPOSALS

2.1 Draft FER Proposals

2.1.1 River Intake

The location of the river intake proposed in the Draft Final Engineering Report, dated December 2000, (DFER) was determined by an alternative analysis described in the Draft Final Engineering Report. The location is not specific nor definite but is attached to a segment of the Missouri River between Poplar at the eastern end and an undefined stretch of Missouri River to the west, but not extending beyond Wolf Point, where total project costs of all intake, water treatment and pipeline facilities and the present value of future electrical costs is lower than at intake points to the east or west of the selected segment.

Costs of alternatives for intake siting are strongly influenced in this project by the structure of demands. While Glasgow represents a large demand on the west side of the project, demands for Wolf Point, Poplar, Scobey, Plentywood and Culbertson dominate the east side of the project. Larger pipelines for longer distances are required with intake on the west side of the project. Similarly, if the intake were moved eastward from Poplar, larger pipelines for longer distances would be required than with the intake near Poplar.

The intake would consist of screens placed immediately above the bed of the stream for the purpose of drawing water directly from the River. Federal biological criteria will be applied to ensure that the screens will limit intake velocities to levels that will minimize the risk of impinging fish or fish eggs. Design velocities will be limited to 0.50 fps and will be subject to approval by federal fishery agencies.

The thalweg, or deepest part of the stream, in the reach of the river immediately south of the community of Poplar, can generally be reached about 150 feet from shore. A site will be sought where the thalweg is near the north bank of the Missouri River on the outside of a meander bend. From the intake screen placed in the thalweg to the bank, a 42 in. raw water pipeline would be constructed, probably from a barge. Water would be conveyed by gravity in the 42 in. raw water pipeline to a wet-well structure at a desirable location above the 100 year floodplain level. The gradient of the 42 in. raw water pipeline would be set to deliver water from the screens to the wet-well by gravity without the employment of pumping facilities.

A siphon design will be considered to reduce the depth of trenching and will operate by gravity given priming at the top of the siphon configuration. Direct gravity flow without siphon action is the most desirable intake from the standpoint of operation. Siphons are sensitive to loss of vacuum but are cost-effective if properly constructed and maintained.

The wet-well structure would be located mid-way between the river bank and the water treatment plant, a total distance in the Poplar area of 1,600 feet. Based on terrain in the area, it was estimated that the base of the wet-well would be excavated to a depth of as much as 30 feet below the surface to permit gravity flow from the Missouri River to the wet-well. The wet well would be constructed with a diameter of approximately 15 feet to accommodate vertical turbine

5 pumps placed to lift raw water to the treatment plant. The pumping units would be housed in a facility with heat and ventilation and with cranes to remove and repair the pumping units. The pumping station would also be equipped with small diameter pipe (3 in.) to deliver air to the screens in the river to maintain them free of debris for continuous unimpaired operation. The intake system from the water treatment plant to the screens would also be equipped with chemical feed (potassium permanganate solution) to oxidize particles taken into the intake that would contribute to formation of disinfectant by-products. Chemicals will be considered at the intake to allow time for mixing and chemical reaction prior to raw water entering the treatment plant.

Costs of the intake are presented in Table 2. In the event the wet-well or treatment plant were sited at an alternate location to that south of Poplar, some variation in distance from the River bank to the wet-well and from the wet-well to the treatment plant would be expected. At the Poplar site for example, movement of the wet-well or treatment plant to a location further north would increase the cost of the intake but decrease costs of the 24 in. finished water pipeline leaving the treatment plant. The 42 in. raw water intake will be constructed of low-pressure materials, probably nonmetallic, between the River and the wet-well. Therefore, any extension of the raw water intake will be partially offset by reduction in the length of high-pressure welded steel or ductile iron pipe leaving the water treatment plant.

The unit costs of the raw water pipeline may be reduced significantly by combining the contract for raw water pipeline with the construction of finished water pipeline leaving the water treatment plant. This would increase the quantity of pipeline construction and decrease unit prices. The unit prices as presented in Table 2 were based on a contract for a small amount of large diameter pipe. The field cost of the intake was estimated at $2,380,000 before mobilization, taxes, bonds, insurance, general requirements and contingencies or $2,856,000 including those items.

TABLE 5-2

RIVER INTAKE COSTS

Unit Total Item Units Quantity Price Price Intake Screens Each 6 15,500 93,000 42" Tee LS 1 150,000 150,000 River Sump, Fabric, RR LS 1 80,000 80,000 42" Raw Water Pipe In River ft 150 400 60,000 42" Raw Water Pipe Buried ft 1,450 350 508,000 Wet Well Structure LS 1 470,000 470,000 Pump Station, 9133 gpm LS 1 900,000 900,000 Air and Permanganate 0 2" PP Pipes ft 1,600 12.00 19,000 3" Air Pipe ft 800 25.00 20,000 Air Vault, Electrical LS 1 70,000 70,000 Buoys LS 1 10,000 10,000 Field Cost $2,380,000

6 2.1.2 Water Treatment Plant

A conventional water treatment plant was proposed for the project. Missouri River raw water quality can be treated satisfactorily by conventional treatment methods to meet federal safe drinking water criteria can produce a finished product with high public acceptance due to low total dissolved solids, hardness, taste and odor. Conventional water treatment involves the removal of suspended particles from the raw water and disinfection of the filtered water to remove microorganisms. As discussed in the previous section, steps will be taken to minimize the potential for trihalomethanes (THM's), haloacetic acids (HAA’s), odor and taste by pre-treatment processes. The following processes are potentially available within the proposed treatment plant, subject to requirements to produce a finished product meeting federal safe drinking water standards and public opinion respecting matters such as fluoridation and methods of disinfection:

1. potassium permanganate oxidation; 2. powdered activated carbon absorption; 3. alum and cation coagulation; 4. flocculation; 5. sedimentation; 6. gravity filtration; 7. pH modification; 8. corrosion inhibitors; 9. disinfection (chlorimination with consideration of ozone for partial disinfection); 10. fluoridation.

Existing water systems currently monitor chlorine, chloramines and/or chlorine dioxide to maintain chlorine residuals above 0.2 mg/l entering the distribution system. No significant changes will be implemented with the regional system, although chloramines are contemplated as the disinfectant agent in order to better comply with the disinfection byproducts rules and to maintain residual levels for longer periods of time.

Maximum contaminant level (MCL) for arsenic was reviewed by EPA and lowered from 50 to 10 micrograms per liter (:g/l) on October 31, 2001.2 Water systems must comply by January 2006. The revision for arsenic followed a request for comment by EPA on 3 :g/l (feasibility level), 5 :g/l (proposed June 2000), 10 :g/l (January 2001 rule) and 20 :g/l.3 The National Research Institute recently concluded that:

...The results of this subcommittee's assessment are consistent with the results presented in the NRC's 1999 Arsenic in Drinking Water Report and suggest that the risks for bladder and lung cancer incidence are greater than the risk on which the EPA based its January 2001 pending rule...4

2Letter of October 31, 2001, from Administrator, Christine Todd Whitman, to The Honorable C. W. Young, Chairman, Committee on Appropriations, House on Representatives.

3Federal Register, Vol. 66, No. 194, Oct. 5, 2001, p. 50761.

4Subcommittee to Update the 1999 Arsenic in Drinking Water Report, September 2000, Prepublication Copy, Arsenic and Drinking Water: 2001 Update, Committee on Toxicology, National Research Institute, p. 12.

7 Lowering the standard for arsenic will require examination of concentrations in the Missouri River at the intake site. While it is probable that the raw water of the Missouri River available to the project does not have concentrations exceeding the new standard, arsenic serves to illustrate the need for adaptability in the water treatment plant. Without provision for supplemental processes, a conventional water treatment plant would remove contaminants carried in suspension but would not necessarily remove dissolved arsenic or other contaminants that may be the subject of future safe drinking water regulations. The conventional treatment plant would provide a product to a future reverse osmosis or more appropriate process to remove contaminants that are presently not known to have an impact on human health at levels currently regulated.

The Preliminary Draft Final Engineering Report describes in detail the sizing of the water treatment plant at 13.1 million gallons per day (9,133 gallons per minute). The cost estimate for this project’s treatment plant was made by comparison of costs of other treatment plants on the Missouri River and throughout the region.

The costs of the treatment plant were predicted by a relationship of finished costs of completed plants in Montana, North and South Dakota, Wyoming and Oklahoma. These costs include all mobilization, taxes, insurance, bonds, general overhead and contingencies and were used to build the cost estimates presented in the Preliminary Draft Final Engineering Report. For consistent presentation of cost estimates, it was necessary to back out the above listed costs (20%) to arrive at a base cost estimate of $13,830,000. When costs of mobilization, taxes, insurance, bonds, general overhead and contingencies are re-applied at the rate for the entire project, the total field cost of water treatment plant becomes $16,740,000.

2.1.3 Pipelines

The cost of constructing pipelines is the largest single cost in the project, accounting for $65 million of the total project costs. Costs were determined from the unit prices presented in Tables 3 and 4. The methodology of arriving at unit pipe prices involved examination of recent bidding on projects in South Dakota, namely the Mni Wiconi and Mid-Dakota Projects. The chief difference between projects built in South Dakota and projects in Montana is the difference in prevailing wage rates in the two states. The prevailing wage rates in South Dakota for labor classifications used in a rural water project of the type proposed for Fort Peck and Dry Prairie are half (or less than half) of the prevailing wage rates in Montana.

The DFER configured flows in the main transmission system to deliver 41 gpm demand to Opheim from a southerly direction through Glasgow and St. Marie and an equal 41 gpm demand to Opheim from a easterly direction through Scobey. Similarly, a 930 gpm demand was provided to Plentywood, in the northeast corner of the project, with half delivered from the west through Scobey and the balance delivered from the south through Culbertson. The DFER addressed the savings that could be realized by delivery of all of the Plentywood demand (930 gpm) through Culbertson. The DFER also presented cost comparisons between main transmission pipelines configured between U.S. Highway 2 and Scobey to the east of the Poplar River along the Flaxville Road and to the west of the Poplar River along the Highway 13.

8 TABLE 3

WEIGHTED UNIT PIPE PRICE BY DIAMETER FORT PECK INDIAN RESERVATION

Total Costs Per Foot AWWA AWWA AWWA AWWA AWWA ASTM ASTM ASTM C-905 C-905 C-905 C-900 C-900 D2241 D2241 D2241 DR 41 DR 25 DR 18 DR 18 DR 14 SDR 26 SDR 21 SDR 17 Nominal 100 165 235 150 200 160 200 250 Selected Diameter Ductile 2.00 2.00 2.00 2.50 2.50 2.00 2.00 2.00 Price

1.5 ------2 ------2.21 2.48 2.80 2.61 3 ------2.99 3.42 3.98 3.28 4 ------5.77 7.02 4.07 4.70 5.46 4.40 6 ------9.52 11.60 6.83 7.98 9.33 7.40 8 ------12.63 15.52 8.73 10.29 12.19 10.28 10 ------18.16 22.26 12.78 15.07 17.84 16.19 12 ------21.70 26.74 15.06 17.87 21.28 19.50 ------14 --15.68 23.66 31.31 ------27.49 16 34.53 30.47 40.55 51.22 ------34.53 18 41.27 ------41.27 20 46.30 ------46.30 24 58.09 ------58.09

TABLE 4

WEIGHTED UNIT PIPE PRICE BY DIAMETER DRY PRAIRIE

Total Costs Per Foot AWWA AWWA AWWA AWWA AWWA ASTM ASTM ASTM C-905 C-905 C-905 C-900 C-900 D2241 D2241 D2241 DR 41 DR 25 DR 18 DR 18 DR 14 SDR 26 SDR 21 SDR 17 Nominal 100 165 235 150 200 160 200 250 Selected Diameter Ductile 2.00 2.00 2.00 2.50 2.50 2.00 2.00 2.00 Price

1.5 ------0.00 0.00 2 ------1.40 1.56 1.77 1.65 3 ------1.90 2.17 2.52 2.08 4 ------3.65 4.45 2.58 2.98 3.46 2.79 6 ------6.07 7.40 4.36 5.09 5.95 4.72 8 ------8.08 9.93 5.59 6.59 7.81 6.58 10 ------11.59 14.20 8.16 9.62 11.38 10.33 12 ------13.89 17.11 9.64 11.43 13.61 12.48 ------14 --10.13 15.28 20.22 ------17.75

9 Pipelines for both the main transmission system and the branches were analyzed in the DFER with pressures up to 200 psi, and costs were applied for pressure classes below 200 psi.

Branch pipelines would rely on pressures generated by pumping stations on the main transmission line. In the DFER analysis, the branch pipelines were not hydraulically connected to the main transmission pipeline. An assumption was made that pressure provided by the main transmission line to all branch pipelines was 80 psi.

2.1.4 Pumping Stations

Each pumping station in the project will be coordinated with a reservoir using supervisory control and data acquisition (SCADA) equipment. Certain pumping station and reservoir combinations will require improvements in the existing electrical distribution system operated by Northern Electric, Sheridan Electric or Valley Electric, the rural electric cooperatives serving the project area.

Pumping station costs from the Mni Wiconi project were also examined as a basis for cost estimating in northeastern Montana. Major cost elements in the pumping stations include (1) site work and structure to house the pumping units and controls, (2) piping, valves and pumping units within the pump house including electrical, heating, ventilation and pump controls and (3) landscaping, fencing and access roads that are not part of the pumping station but are necessary for access and security. Costs per horsepower generally decline from the smallest pumping station to the largest. Some stations in the Mni Wiconi Project had extra costs associated with requirements of the National Park Service for facilities placed in the Badlands National Park.

For the current project, the Mni Wiconi Project experience was modified to form a basis for pump station costs as presented in Table 5. Total station costs for pump stations 1 through 4 were adopted from Mni Wiconi. Total station costs for pump stations 5, 6 and 7 were based on $2,000 per horsepower, and total station costs for pump stations 8 and 9 were based on $5,000 per horsepower. The costs of total stations with capacity less than 160 horsepower were based on pre-assembled pumps stations constructed outside the project and delivered to the project site for installation. Therefore, the costs of labor in assembly of the pump stations would be incurred at a manufacturing plant, either in Montana or elsewhere, and would be at rates applicable to

TABLE 5-5

PUMPING STATION COSTS FORT PECK/DRY PRAIRIE

Pump Fort Station Site Fence/ Peck Total Size Work/ Total Landscape/ Total Station Pump Station Name (hp) Structure Station Roads Pre-Built Per HP Pump Station 1 2,000 150,000 1,123,393 15,000 1,288,393 562 Pump Station 2 500 100,000 355,000 15,000 470,000 710 Pump Station 3 240 100,000 229,800 15,000 344,800 958 Pump Station 4 160 90,000 220,000 12,000 322,000 1,375 Pump Station 5 25 80,000 50,000 12,000 142,000 2,000 Pump Station 6 7.5 75,000 15,000 12,000 102,000 2,000 Pump Station 7 2 30,000 4,000 10,000 44,000 2,000 Pump Station 8 1 15,000 5,000 10,000 30,000 5,000 Pump Station 9 0.5 15,000 2,500 10,000 27,500 5,000

10 manufacturing rather than construction. Differences between South Dakota and Montana in prevailing wage rates for heavy construction are significant and would be applicable; but small differences in construction cost would be expected between the two states due to the use of most labor in the manufacturing and not the construction of the pumping stations.

In addition to the costs of the "total station", site and structural work were estimated to range from $15,000 to $150,000 per pumping station (Table 5). Fencing, landscaping and roads for access to the pumping stations were estimated to range from $10,000 to $15,000 per pumping station. Costs of a completed pumping station were projected to range from $562 to $5,000 per horsepower from a 2,000 horsepower pump station to a 0.5 horsepower pump station, respectively.

2.1.5 Reservoirs

Reservoirs would be provided for each pumping station in the project. The purpose of the reservoirs is to provide a source of water at the suction end of pumping stations to improve operations. When the pumping station is seeking more flow than the upstream pipeline can provide, the reservoir is available to supply additional water. Moreover, reservoirs will conserve usable storage for use during peak periods of the day.

On the main transmission lines, storage in the amount of 1,095,960 gallons was provided at the first pumping station to deliver water during two hours of backwash at the water treatment plant at the maximum day rate. Criteria for other reservoirs on the transmission lines of the project (not the branch lines) will provide six hours of difference between (a) peak hour demand for the rural household connections between pumping stations and (b) maximum day flow. Storage for an additional hour at one-third of the maximum day flow rate was also provided for operational enhancement of pump performance. These criteria produce a requirement for 2,766,560 gallons of storage along the main transmission line that connects Glasgow to Culbertson on the south, Culbertson to Plentywood on the east, Plentywood to Scobey and Opheim on the north and Opheim to Glasgow on the west. The main transmission line also connects Wolf Point with Scobey.

The preliminary design of the transmission line provides water to Plentywood and Opheim from two directions and results in combined storage requirements at Plentywood of approximately 145,000 gallons and combined storage requirements at Opheim of 37,000 gallons. Project storage from the main transmission system will supplement existing storage in the project communities.

The branch lines are currently designed with the hydraulic model for peak hour flows. The pipelines have been sized to carry peak hourly flows that do not require supplements from storage. The criteria described above for improved operation of the pumps generally requires much less than 5,000 gallons. On this basis, a determination was made to provide a minimum of 5,000 gallons in storage reservoirs at each branch line pumping station. A total of 915,000 gallons would be provided at the 89 small, booster pumping stations on the branch lines. This determination may be revisited as more detailed plans are made for the creation of fire service districts in the rural areas.

11 Costs of reservoir storage were derived from experience in South Dakota. Five (5) elevated tanks and twelve (12) ground level storage tanks have been bid in the Mni Wiconi Project with costs (indexed to October 1998) ranging from $0.76 to $2.61 per gallon. Cost per gallon vary from the higher end of the range for small reservoirs to the lower end of the range for larger reservoirs. In general elevated tanks are more costly than comparably sized ground level storage tanks. For the purposes of cost estimating, ground level storage tanks were assumed adequate at all pump stations.

2.2 VE Proposals

The discussion below describes the proposals made by the VE team. Life-cycle costs and life-cycle savings, as presented in this report, were measured relative to the baseline (DFER) proposal.

2.2.1. Pipeline Reconfiguration with Intake and Water Treatment Plant at Poplar

Proposal No. 1A. Revise the design parameters and consider alternative allocations of flow between the three main core lines (eliminate the interconnecting points at the northwest and northeast corners of the system) with intake and treatment plant at Poplar The estimated life-cycle savings of this proposal are $10,172,000 before deducting any study and/or implementation costs.

The VE study team reconfigured the main transmission pipelines from the intake at Poplar and incorporated the following design concepts that were different from the Draft Final Engineering Report (DFER):

• Relocation of reservoirs at high points between pump stations rather than at each pump station

• Variation of system pressure at booster stations sites above and below 200 psi (462 feet).

• Selection of an alternate pipeline route between the main pipeline transmission system along Highway 2 and Scobey. The alternative route selected by the VE study team was East of the Poplar River, and the route in the DFER was West of the Poplar River.

• The delivery of all water to Plentywood and Opheim along a single route of the main transmission pipeline rather than along converging routes as presented in the DFER.

The objective of the VE study team was to reduce project costs through reduction in the number of pumping stations required along the main transmission line. By achieving this objective, present value of life-cycle costs, including annual operation and maintenance costs, could be reduced. Some commensurate increase in initial pipe investment would be required. The VE study team concluded that the number of pumping stations along the main transmission lines could be reduced from 20 to 11 resulting in life-cycle cost savings of $10,172,000.5

5Bureau of Reclamation, April 30, 2001, p. 28.

12 This is an independent alternative not dependent on other alternatives.

2.2.2 Pipeline Reconfiguration with Intake and Water Treatment Plant Below Fort Peck Dam

Proposal No. 1B. Revise the design parameters and consider alternative allocations of flow between the three main core lines (eliminate the interconnecting points at the northwest and northeast corners of the system) with intake near Fort Peck Dam and Water Treatment Plant near Nashua. This proposal has the same relative life-cycle cost as the baseline proposal ($1,100 more). Should this proposal be implemented Life Cycle Cost savings would be achieved with the treatment of the better quality water with the less costly Micro/Nano Filtration plant in combination or separately with no pre- sedimentation requirements.

Both the VE study and the DFER considered an intake alternative at the Southwest corner of the project. The DFER examined an intake above Fort Peck Dam and determined that initial investment costs would increase from $192,870,000 (base alternative) to $202,927,000, an increase of $10,057,000. The VE study examined an intake below Fort Peck Dam and determined that life-cycle costs would increase by $10,173,000 relative to VE alternative 1A. This is an independent alternative not dependent on other alternatives.

2.2.3 Water Treatment Alternatives

Microfiltration with Pressurized Delivery from Intake

Proposal No. 2A. Reconfigure intake and WTP to use mechanical pre-sedimentation followed by micro filtration. The estimated life-cycle savings of this proposal are $6,823,368 before deducting any study and/or implementation costs.

VE Proposal 2A differs from the baseline proposal in the following unit processes:

1. Ferric chloride is used in VE Proposal 2A instead of alum for improved arsenic removal. Both ferric chloride and alum are excellent coagulation chemicals. Ferric chloride is better suited if arsenic is a concern. The VE team used a dose of 5 mg/L ferric chloride in their analysis for arsenic removal. Sponsor analysis assumed that the baseline proposal would have an average alum dose of 25.

2. The baseline proposal was assumed to include cationic polymer as a coagulant aid. Cationic polymer has been shown to cause problems with membrane treatment systems, so the cost of this system was deleted from VE Proposal 2A.

3. A “Superpulsator” clarifier is used in VE Proposal 2A instead of conventional flocculation/sedimentation basins. This is a form of what is usually termed sludge

13 blanket clarification. This process may be applicable for treating many types of raw water and can operate at higher loading rates than conventional facilities. Pilot testing is warranted.

4. Microfiltration (MF) membrane treatment is used in VE Proposal 2A instead of conventional gravity media filtration. Membrane treatment is becoming increasingly cost-effective as its use increases. It is becoming more popular as a treatment system due to its ability to remove extremely small particles and contaminants such as Giardia and Cryptosporidium. MF membranes can typically remove particles larger than about 0.1 microns, while conventional filtration is limited to particles larger than about 1 micron.

This proposal is the same as alternative 2B with the exception that water would be delivered by gravity with alternative 2B. Either 2A or 2B could be selected, not both.

Microfiltration Supplemented by Nano-filtration with Pressurized Delivery from Intake

Proposal No. 3A. Reconfigure intake and WTP to use mechanical pre-sedimentation followed by micro filtration and nano-filtration. The estimated life-cycle cost of this proposal is $15,678,435 before deducting any study and/or implementation costs.

VE Proposal 3A is similar to VE Proposal 2A, except that nanofiltration (toNF) membrane treatment has been added to provide additional treatment on a portion of the flow. NF membranes will remove particles down to about 0.001 microns in size. The VE team proposed NF membranes as a means to provide arsenic removal without the need for ferric chloride. However, ferric chloride or some other primary coagulant would still need to be added for the pretreatment processes.

This proposal is the same as alternative 3B with the exception that water would be delivered by gravity with alternative 3B. Either 3A or 3B could be selected, not both.

Media Filtration with Superpulsator and with Pressurized Delivery from Intake

Proposal No. 4A. Reconfigure intake and WTP to use mechanical pre-sedimentation followed by multi-media filtration. The estimated life-cycle savings of this proposal are $16,569,750 before deducting any study and/or implementation costs.

VE Proposal 4A is very similar to the baseline proposal in that it uses gravity media filtration instead of membrane treatment. The differences from the baseline proposal are that ferric chloride is used instead of alum as the primary coagulant for arsenic removal, and a Superpulsator clarifier is used instead of conventional flocculation/sedimentation.

14 This proposal is the same as alternative 4B with the exception that water would be delivered by gravity with alternative 4B. Either 4A or 4B could be selected, not both.

Water Treatment Alternatives with Gravity Delivery from Intake

Proposal No. 2B. Reconfigure intake and WTP to use gravity filled pre-sedimentation basin followed by micro filtration. The estimated life-cycle savings of this proposal are $17,121,875 before deducting any study and/or implementation costs.

Proposal No. 3B. Reconfigure intake and WTP to use gravity filled pre-sedimentation basin followed by micro filtration and nano-filtration. The estimated life-cycle cost of this proposal is $6,322,765 before deducting any study and/or implementation costs.

Proposal No. 4B. Reconfigure intake and WTP to use gravity filled pre-sedimentation basin followed by multi-media filtration. The estimated life-cycle savings of this proposal are $26,822,857 before deducting any study and/or implementation costs.

VE Proposals 2B, 3B, and 4B are similar to the three previous VE proposals in terms of the major WTP components. The differences are in the intake system and the initial flocculation/sedimentation process:

• The VE proposals utilize a multi-level gated structure at the river to act as an intake to an open channel by gravity. This channel conveys the water to the WTP without pumping as contrasted with the baseline proposal, which requires pumping.

• At the WTP site, the water flows into large pre-settling cells for initial pretreatment instead of using conventional flocculation/sedimentation facilities.

All water treatment plant proposals (2A, 2B, 3A, 3B, 4A and 4B) are independent proposals. Only one of the six could be selected as an alternative to the baseline proposal.

2.2.4 Chloramines

Proposal No. 5. Chloramine disinfection in lieu of chlorine disinfection with re- injection points. The estimated life-cycle savings of this proposal are $749,366 before deducting any study and/or implementation costs.

The DFER also contemplated the use of chloramines. Regional water projects benefit from chloramine as a disinfectant due to the longer life of the residuals, regarded as a potential increase from one to three weeks. This longer life reduces the requirements for re-injection of disinfection at pumping stations or other locations in order to maintain residual levels where travel time from the water treatment plant to the far corners of the project is an estimated 20 to 30 days during low demand winter months.

This alternative may be selected if no other alternatives are selected or in combination with other alternatives.

15 2.2.5 Gravity Intake

The gravity intake, which is the key difference between alternatives 2A and 2B, 3A and 3B, and 4A and 4B, may be selected for any of the water treatment plant alternatives, namely the conventional water treatment as proposed in the DFER or VE alternatives 2, 3 and 4.

16 3. EVALUATION AND DISCUSSION OF VE PROPOSALS

3.1 Proposal 1A: Revise Design Parameters and Flow Allocation in Main Pipeline System with Intake at Poplar

This proposal contemplated net life-cycle savings of $10,171,712. Table 6 summarizes the results of detailed analyses following the VE study, and Table 7 provides more detail for the main transmission system. These analyses were conducted and coordinated between the Bureau of Reclamation, VE team members and the design engineer. VE concepts were included in the analyses. As shown an Table 6, alternative1A would save an estimated $179,827 in annual electrical and pump station OMR costs, a significant savings that would reduce those costs from about $817,000 to $637,000 annually (present value reduction from $17,551,000 to $13,684,000, a difference of $3,863,000).

In the process described above, the original VE layout, flows, pipeline diameters, pump locations and other parameters were “modified” by VE team members to reflect a better, post-VE understanding of the main pipeline system. Similarly, minor “modifications” were made in the Opheim and Plentywood areas to eliminate pipe to match the “modified” VE proposal and analysis. The results are reflected in Tables 6 with terminology as described here.

Construction savings would be realized by reducing the number of mainline pumping stations from 18 to 12 and a corresponding reduction in electrical motor input from 4,262 to 3,186 horsepower. The number of branch line pumping stations would not be reduced, but the total electrical motor input for those pumping stations would decline from 452 to 419 horsepower, a reduction of 33 horsepower.

The foregoing savings would be achieved by increasing pipe diameters to reduce friction or head losses in the pipeline. Pressure class would be increased from 200 psi in the DFER to 250 psi. The effect of these design changes was to reduce the project costs (fields cost plus mobilization, taxes, bonds, insurance, general requirements, contingencies and noncontract costs) of pumping stations by $3,083,110 and to increase pipeline costs by $16,595,227. The net effect would be an annual savings of $179,827 (present value of $3,863,000) in annual electrical and pump station OMR costs and a net project construction cost increase of $13,512,117. Life-cycle costs would increase by $9,649,035.

The evaluation of the alternative along the main pipeline system included the re- distribution of flows to Opheim and Plentywood. The Opheim demands of 81 gpm were directed from the water treatment plant at Poplar to Scobey and then west to Opheim. The Plentywood demands of 930 gpm were directed from the water treatment plant at Poplar to Culbertson and then north to Plentywood. In the DFER, the demands to these communities were split and delivered from two directions rather than one direction. Pump station pressures were increased to 250 psi except at locations where those pressures would have been excessive. Pressure classes of pipe and corresponding costs were adjusted to meet the VE requirements. Pipe sizes were provided by the VE team members of the Bureau of Reclamation.

17 18 19 Only selected branch pipelines were analyzed. The identification of those branch lines is presented in Table 6. Branch 1EE is the branch immediately east of Culbertson that serves Bainville and areas to the north, south and east of Bainville. Branch 13EE is the branch that serves the area northeast of Plentywood, including Westby. Branch 12PWN is the branch immediately north of Scobey. These three branches were considered representative of Dry Prairie. All pumping stations in Dry Prairie in the DFER have a combined 270 horsepower (Attachments C). The selected branches accounted for 131 horsepower or 48% of the total.

Branches analyzed on the Fort Peck Indian Reservation are also listed in Table 6. The two branches east of Poplar are branches 2EN and 4EN. The remaining branches are west of Poplar: 1WN, 6WN, 9WN and 12WN. The selected branches account for 30 pumping stations with a combined 321 horsepower. The total horsepower on the Reservation in the DFER was 334 horsepower. Therefore, the pumping stations included in the analysis accounted for 96% of the total branch line horsepower.

As discussed previously, the DFER assumed that the pressure available at the start of each branch line, whether on the Reservation or in the Dry Prairie region was 80 psi. In the re- evaluation, the branch line pressures were linked to the main transmission pipeline. The DFER analyses were based on hydraulic models where the main transmission system included nearly 1,000 pipe segments and several of the larger branch lines also included nearly 1,000 pipe segments. The hydraulic models did not permit the linking of the main transmission line with the branch pipelines. However, the re-evaluation following the VE study was based on spreadsheet models, where linking was more feasible. Therefore, the results in Table 6 are based on linkage of branch line pressures to the main pipeline system. This resulted in greater available pressure for some branch lines and less available pressure for others than assumed in the DFER.

Branches were analyzed with starting pressures as described above. Booster pumps were increased from 200 to 250 psi in keeping with the VE recommendations. No pipeline diameters were modified. In general, the branch studies caused the relocation of pump stations from nearer to the main pipeline system to further from it. This did not result in overall reductions in the number of pump stations on the primary branch lines, and there were additions of small pump stations on some of the second and third tier branch lines. If there were adoption of VE concepts, final design would work on increases our pipe diameters to eliminate the additional pump stations added to second and third tier branch lines.

In theory, the VE concepts would have reduced the number of pumping stations on branch lines rather than increase them. In practice, the branch lines are sensitive to location of pumping stations and their effect on the hydraulic grade line. The physical circumstances along the branch lines left some secondary branches with more pressure than necessary and others with less pressure than necessary to avoid the addition of small pump stations.

The VE study suggested that insufficient costs were provided in the DFER ($1,000,000) for power transmission to pumping stations. Annual electrical costs are estimated at more than $650,000 of which one third is for payment of Western energy costs (15.5 mills per kilowatt hour,

20 $0.0155 m/kwh) and two-thirds is for payment of OMR expenses (30 m/kwh) of the participating rural electric cooperatives and/or investor owned utilities.

As in other projects of this nature, the added cost of operating and maintaining the rural electric cooperatives (aside from service of new debt) is minimal. Therefore, as in other projects, there is considerable opportunity for capital improvement of the facilities operated by the rural electric cooperatives from the revenues received from the Fort Peck Reservation Rural Water System. Sufficient revenues (estimated at $450,000 annually at the rate of 30 mills per kilowatt hour) will be received by the rural electric cooperatives to finance (at 5% over 30 years) as much as $7,000,000 in capital improvements without increasing electrical rates to its members. Alternatively, the sponsors could reach agreement with the rural electric cooperatives for the sponsors to finance the improvements through wheeling contracts with the rural electric cooperatives to divert up to 30 mills per kilowatt hour of the total 45 mills per kilowatt hour to new power line construction. To the extent the rural electric cooperatives do not require the $450,000 annually for new capital improvements, discounts in the wheeling (OMR) costs of the cooperatives could be made available to the Assiniboine and Sioux and Dry Prairie Rural Water Systems, thereby lowering costs to the water project while simultaneously lowering cost per kilowatt hour to its existing cooperative members.

These concepts require acceptance and agreements between sponsors and the rural electric cooperatives. Half of the revenues discussed above, in combination with the $1,000,000 programmed in the DFER for power improvements, would create $4,500,000, an amount considered adequate for 125 miles of upgrades, which is considered more than is required.

Single phase power will be adequate for all pump stations in the 10 to 15 horsepower range. Five pump stations on the main transmission line have requirements less than 15 horsepower. Of the 90 pump stations on the branch lines, only 10 require more than 15 horsepower, and none are larger than 30 horsepower. The final location of pump stations and their ultimate capacity cannot be determined until design approaches final stages. Refinement to reduce the number of pumping stations with capacity greater than 10 to 15 horsepower is not cost-effective at the time of the Final Engineering Report due to the changes that will be made as construction advances over the next 10 years and as changes are made to accommodate new conditions. The sponsors are committed to combinations of main pipeline and branch pipeline pressures that will minimize the cost of pumping stations and corresponding power line improvements.

The clear advantage of the VE proposal is that it reduces future electrical and OMR costs associated with pumping stations. If there were marked increases in future electrical rates, sponsors electrical costs would only increase on 75% of the electrical demands given in the DFER. Fewer electrical distribution upgrades would be required along the main pipeline transmission system, and the reduction in horsepower of pumping stations on the branch lines would reduce the number of pumping stations with more than 10 to 15 horsepower that will require three phase power. The disadvantage of the VE proposal is that it increases pipeline costs by more than the life-cycle savings of the design in the DFER.

21 This VE proposal, as formulated in all its parts, is not accepted for reason that it increases life-cycle costs. The VE concepts were sound, however, and the limit on the preliminary design to 200 psi will be lifted in final design to permit pressures up to 250 psi, where savings will result. The part of the VE proposal that redistributes demands for Opheim and Plentywood will be adopted, because savings will result. Further investigation will be undertaken in final design to determine the best route from U.S. Highway 2 to Scobey, depending on the final location of the intake between Poplar and Wolf Point. This is an adoption of the VE concepts for best routing of this segment. Reservoir location concepts in the VE proposal at high points are sound, provided the high points are not an significant distance from the pipeline. The basic reservoir location concepts in the VE proposal do not differ significantly from the DFER and will be carried forward.

3.2 Proposal 1B: Revise Design Parameters and Flow Allocation in Main Pipeline System, Change Intake to Dredge Ponds near Nashua, Account for Water Treatment Differences

Table 8 summarizes the results of re-evaluation of the main pipeline transmission system with change in intake location to the dredge ponds below Fort Peck Dam near Nashua. Pump station pressures were increased to 250 psi, which matched the pressure assumption for alternative 1A. Pipeline sizes were increased to minimize the number of pumping stations with a corresponding increase in pipeline costs. Pipeline pressure classes increased and contributed to cost increases of pipelines. No re-analysis of branch lines was made due to the findings presented in Table 6, where cost increases (not savings) of reconfiguration was estimated at $343,000. This was considered a relatively minor amount.

As shown in Table 8, power requirements declined from the base case of 4,262 horsepower (Table 6) to 3,269 horsepower, slightly less than the decline in horsepower for alternative 1A (Table 6.... 3,186 horsepower). Similarly, annual electrical costs declined from $632,746 (Table 6) to $485,328. Annual pump station OMR costs declined from $96,558 (Table 6) to $71,158. The number of pumping stations declined from 18 to 10.

Offsetting the savings in pump station construction costs and annual pump station electrical and other OMR costs were increases in pipeline costs. Field pipeline costs increased from $31,292,651 to $48,138,546, and total pipeline and pumping station field costs increased from $36,906,907 (Table 6) to $51,617,123. Project costs for pipeline and pumping stations increased from $58,054,565 to $81,193,735, an increase of $23,139,170.

There are potential differences in water treatment plant alternatives at the Poplar and Nashua intake sites. When those differences are taken into account, as shown in Table 9, the life- cycle impact of siting the intake near Nashua is an increase in the present value of all costs of $18,112,553 for a conventional water treatment plant and an increase of $18,925,568 for a micro- filtration plant.

22 23 24 The water treatment plant alternatives are discussed more fully in the section which follows. However, in the analysis of alternative1B, differences between sediment in the Missouri River near Poplar and below Fort Peck Dam at the dredge ponds near Nashua were addressed. Those differences will be significant. Sediment concentrations on the Missouri River near Culbertson are considered representative of Poplar. On the lower extreme, less than 133 mg/l is expected 10% of the time; and on the upper extreme, suspended sediment concentrations will be less than 1,600 mg/l an estimated 99% of the time. Median concentrations are 260 mg/l. At the dredge ponds below Fort Peck Dam and upstream from Nashua, suspended sediments are not expected to vary significantly and will normally be less than the 133 mg/l typical of the Missouri River at greater distances downstream from the Dam when the River is clear. With natural spillway discharges and the implementation of an artificial spring rise at Fort Peck Dam, increased suspension of sediments can be expected immediately downstream from the dam, but relatively infrequently, perhaps every third year. Water treatment plant facilities to remove sediment will be needed at the dredge ponds for infrequent and relatively short duration events. The proposed “spring rise” will carry water over the spillway of the Dam and will cause unknown levels of turbidity below the Dam and at the dredge ponds. Therefore, flocculation/sedimentation ponds were considered necessary with a conventional water treatment plant at Poplar or Nashua, and a super pulsator/clarifier was considered necessary at both sites with microfiltration.

A 7% increase in suspended sediments in the Poplar and Culbertson vicinity has been projected for the proposed “spring rise” from Corps of Engineers’ data. Flocculation/ sedimentation ponds or a super pulsator clarifier at the Poplar intake site will be required for the historical level of suspended sediments and the projected increase. The effect of the spring rise is considered more of a factor at the Nashua site than at the Poplar site.

Differences in water treatment plant OMR costs are presented in Table 9 to reflect differences between intake sites at Poplar and Nashua. Intake replacement costs have been reduced at the Nashua site to reflect less wear on impellors on vertical turbines. Similarly, chemicals have been reduced at the Nashua site to reflect historic experience by the City of Glasgow.

The life-cycle effect of the savings in annual OMR costs on the main transmission pipeline and water treatment plant and increase in project construction costs with intake near Nashua is summarized in Table 9 for a conventional water treatment plant (-$18,112,553) and for a microfiltration plant (-$18,925,568). The costs differences of an intake at Poplar and Nashua are significant, irrespective of any further refinement in construction or OMR costs, such as the deletion of flocculation/sedimentation ponds or a superpulsator clarifier..

The advantages and disadvantages of this proposal are the same as those listed for alternative 1A. The clear distinguishing advantage, not incorporated in alternative 1A, is the lower level of suspended sediment that would be present in the Missouri River below Fort Peck Dam. The clear distinguishing disadvantage is the cost of this alternative. This alternative is not accepted by the sponsors.

25 4.3 Water Treatment Alternatives to Conventional: Superpulsator Clarifier with Micro-Filtration, Nano-Filtration or Media Filtration

The project construction costs, annual OMR and life-cycle costs of water treatment plant alternatives are presented in Table 10. The sponsors, the design engineer, and Bureau of Reclamation have agreed on the presentation of costs in Table 10 and recognize that more detailed design level investigations can have a marked impact on the preliminary, reconnaissance level costs provided. The sponsors and Bureau of Reclamation agree that the conventional water treatment (baseline alternative), microfiltration proposal (2A) and media filtration with superpulsator clarifier (4A) will be further investigated in final design before a selection is made. Both the microfiltration and media filtration alternatives have apparent life-cycle cost savings of

26 $4,130,000 and $11,544,000, respectively, relative to the conventional water treatment plant proposed in the DFER. Nanofiltration (3A) is agreed by all to produce a higher quality finished water but at too great a cost, an estimated life-cycle cost increase of $21,177,000.

The following recommendations are made for the post-FER phase of the rural water system development:

1. A site will be selected and site specific details will be developed to refine the intake system costs and WTP treatment needs and costs.

2. The arsenic rule from EPA is final at 10 micrograms per liter (:g/l) . The use of alum or ferric chloride as a primary coagulant should be evaluated in detail for the new standard. Preliminary jar tests could be performed to better estimate average dosages needed for each chemical. Other coagulants receiving much attention today include polyaluminum chloride (PACI) and partially neutralized alum-polyaluminum hydroxy sulfate (PAHS). In addition to typical dosages and chemical costs, the following factors should be considered:

• Effectiveness of coagulation and turbidity reduction • Effectiveness of arsenic removal. • Effectiveness of organics removal and impact on reducing disinfection by- products. • Sludge production amounts and settling/dewatering characteristics. • pH and corrosion effects. • Ease of handling and storage.

3. Preliminary costs estimates indicate that a Superpulsator type clarifier may be more cost- effective than conventional flocculation/sedimentation. More detailed sizing based on recommendations from manufacturers and a review of other facilities treating similar waters should be performed. Pilot testing will be warranted since this process does not work well with all types of waters and contaminants. In addition to the Superpulsator clarifier, other types of alternative flocculation/sedimentation systems should be evaluated, including:

• Solids contact clarification. • Conventional (not pulsed) sludge blanket clarification. • Contact clarification. • Ballasted clarification.

4. Preliminary cost estimates indicate that MF membrane treatment is cost-effective on a life cycle basis. Moreover, membrane treatment offers better particle removal characteristics than conventional filtration. Pilot testing may be required in order to establish design criteria for the system and better estimate costs. Membranes and their operating characteristics are extremely site specific and it is not a recommended practice at this time to implement a membrane system without a detailed pilot test program. See section 4.5 for discussion of alternatives 2B, 3B and 4B.

27 3.4 Chloramines

• Proposal No. 5. Chloramine disinfection in lieu of chlorine disinfection with re- injection points. The estimated savings of this proposal are $749,366 before deducting any study and/or implementation costs.

This proposal is accepted without modification. It was the intended method of disinfection in the DFER6, although the intent was not consistently reflected in all parts of the DFER7.

3.5 Gravity Intake

The gravity intake, which is the key element in alternatives 2B, 3B, 4B and 6, is discussed here. Table 11 summarizes design assumptions for the gravity intake at Poplar.

6DFER, p. 3-23.

7DFER, p. 5-5

28 The 100 year flood elevation at Poplar is 1,952 feet above mean sea level. This elevation was adopted as an invert for an open channel delivering water by gravity to a water treatment plant on the boundary of floodplain. Note that the water treatment plant at this location would have a lower level below the floodplain to receive water from the open channel by gravity. It was assumed that an open channel could be built from the water treatment plant upstream on a mild slopes (1 foot per 10,000 feet). A flatter slope was not considered workable, and a steeper slope would require an increasingly longer open channel to reach a diversion point on the Missouri River.

The U.S. Geological Survey maintains a gaging station at Wolf Point with an elevation of 1,958.57 feet above mean sea level representing the elevation of zero flow in the Missouri River: the point at which the channel is the deepest. The location of the gaging station is on the Highway Bridge to Circle east and south of Wolf Point. An elevation of 1,959.37 feet at this location represents a relatively low flow in the Missouri River at about 5,000 cfs. It was determined that an open channel on a slope of 1 foot per 10,000 feet would have an invert elevation of 1,962.60 feet at the location of the gaging station based on a measured distance from the water treatment plant of 106,000 feet. Therefore, the invert of an open channel would be approximately 3.23 feet above the minimum invert needed at the gaging station to divert water at flows in the Missouri River above 5,000 cfs. More open channel than 106,000 feet (20.1 miles) would be required, including a channel that would traverse the community of Wolf Point at unknown, but high, costs.

Setting the additional distance of canal aside, a channel cross-section was developed to carry 20.30 cfs, the design capacity of the water treatment plant. A 5 foot bottom width was assumed with 2:1 side slopes on the canal banks. On this basis, water would flow at a depth 1.00 feet (Table 5) and at a velocity of 3.02 fps. It was assumed that the velocity would not erode the channel and that the channel would not require lining to prevent excessive seepage losses over the 20.1+ miles required for the channel. A free-board of 2 feet was added to the wetted area of flow, and channel excavation of 82,444 cubic yards was computed. At a cost of $20.00 per cubic yard, the cost of open channel excavation would be $1,649,000. The cost of a head gate was not determined, but experience with irrigation facilities on a river of the nature of the Missouri River would indicate a cost of $500,000 or greater. Based on a 50 foot width for construction and the assumption that land could be acquired for $500 per acre, land costs were estimated at $60,836.

The initial project costs for a gravity open channel are summarized in Table 12 for comparison with the base intake cost. Worthy of note is the fact that no costs for crossing roads, streams, railroads and other obstacles for an open channel are included due to the considerable effort required to improve on the costs presented. The route for an open channel was placed on U.S. Geological Survey 7.5 minute quadrangles, and it was noted that much of the distance was in close proximity to the Missouri River, and all was within its floodplain. No costs are included for protection of the open channel from flooding. No costs are included for environmental mitigation for those reaches of the open channel crossing the cottonwood forest riparian zone.

Table 12 also presents the life-cycle costs of the basic intake and gravity intake. The cost difference is $72,000 and favors the baseline intake even though pumping costs are involved with

29 30 the baseline intake. The pumping costs for the baseline intake ($15,500 annually) are for lifting the design flows over a vertical distance of 40 feet to the water treatment plant.

On the basis of the costs presented in Table 12, it was clear that the VE alternative had merit in its formulation. However, founded on limited costing, (believed to significantly underestimate the costs of an open channel), the alternative is not accepted. Factors influencing the decision, aside from cost, land owner issues and environmental issues, are concerns that maintaining a flow in the winter months would be difficult, if not impossible. Irrigation systems on the Fort Peck Indian Reservation function well with open channel diversion and conveyance, but they do not operate in the winter months. Even if flow could be maintained without freezing, ice would form on the surface, and blockage and breach of canal banks would be a risk. The baseline intake, albeit with a pumping system and annual cost of $15,500, is considered more dependable for the reason that all facilities are buried below frost.

Replacement costs of the open channel were based on the assumption that the open channel would not be damaged by flood during its operation. That assumption is unrealistic for the reason that the entire canal system from Poplar to Wolf Point lies within the 100 year floodplain. In the event of a significant flood along the Missouri River, considerable time would be required to restore the open channel. The basic intake may be subject to scour during flood, but could be more readily repaired. The challenge in final design of the basic intake, a challenge successfully met by comparable facilities in Montana at Great Falls and elsewhere along the Missouri River in the northern Great Plains, will be to select a site with channel stability, such as the site at Poplar.

31 4. SYNOPSIS

The Final Engineering Report will include an appendix containing the Value Engineering Report and this Accountability Report. Reference will be provided in the Final Engineering Report to this appendix for more detailed information than will be provided in the Final Engineering Report.

In the water treatment plant chapter of the Final Engineering Report, the conventional water treatment plant will be presented as the basis for costs. Narrative will be provided briefly describing the microfiltration and mediafiltration alternatives (with discussion of the potential savings), both with superpulsator clarifier as an alternative to the flocculation/sedimentation ponds, associated with the conventional water treatment plant. The water treatment plant chapter will also address chlorimination as the choice for disinfection.

A section will be provided in the Final Engineering Report referring to the appendix and briefly describing the results of the analysis of alternative 1A and the design concepts embraced by alternative 1A. Costs in the Final Engineering Report will be the modified original costs to reflect change in distribution of flows to Opheim and Plentywood. Reference will be made to the VE conclusion that part of the pipeline between St. Marie and Opheim (primarily across State lands) can be eliminated in the absence of interest by lessees of State lands or the State of Montana for livestock purposes. Reference will also be made to the VE conclusion that a smaller segment of pipeline immediately west of Plentywood can be eliminated.

No narrative will be provided with respect to the siting of the intake and water treatment plant near Nashua or to gravity delivery of water from the Missouri River to the water treatment plant.

32 33 34 35 36 37