FINAL REPORT WEST METRO REGIONAL WATER FEASIBILITY STUDY

F I N A L R E P O RT

WEST METRO REGIONAL WATER FEASIBILITY STUDY

SEPTEMBER 2020

TABLE OF CONTENTS1.0 EXECUTIVE SUMMARY.....................................................................................................................1

2.0 INTRODUCTION/PURPOSE............................................................................................................13

3.0 EXISTING WATER TREATMENT AND DELIVERY ASSETS......................................................................16

4.0 POPULATION, CURRENT WATER DEMANDS AND FORECASTED GROWTH......................................22

5.0 PROPOSED FUTURE INFRASTRUCTURE TO MEET PROJECTED DEMANDS........................................32

6.0 FINANCIAL IMPACT.........................................................................................................................47

7.0 SUMMARY OF FINDINGS................................................................................................................58

F IGURESFigure 1.1 West Metro Regional Water, Water Service Planning Area (2020)..............................................2

Figure 1.2 Population and Daily Water Demand Projections......................................................................5

Figure 1.3 Peak Water Demand and Water Treatment Capacities..............................................................7

Figure 1.4 West Metro Regional Water Hydraulic Strategy.........................................................................8

Figure 1.5 Average Customer Water Bill – 5,000 gallons/month, Current Water Bill.................................10

Figure 1.6 Average Customer Water Bill – 5,000 gallons/month, Proposed Water Bill, All Communities Stay Together.............................................................................................................................11

Figure 2.1 West Metro Regional Water, Water Service Planning Area (2020)............................................15

Figure 3.1 West Metro Regional Water, Existing Core Infrastructure..........................................................19

Figure 3.2 Proposed Pressure Zones.......................................................................................................20

Figure 4.1 Existing (2020) and Projected City Limits.......................................................................................23

Figure 4.2 DMWW Metro Population Projections....................................................................................25

Figure 4.3 Per Capita Water Demands by Community............................................................................27

Figure 4.4 DMWW Projected Metro Average Day Demand.....................................................................28

Figure 4.5 DMWW Projected Metro Peak Day Demand..........................................................................29

Figure 4.6 Population Projections and Peak Day Water Demand..............................................................30

Figure 4.7 Population and Daily Water Demand Projections....................................................................31

Figure 5.1 Direct RO Treatment Schematic............................................................................................37

Figure 5.2 Lime Softening Schematic....................................................................................................38

Figure 5.3 Proposed Raw Water Supply and Water Treatment..................................................................39

Figure 5.4 Water Treatment Strategy......................................................................................................40

Figure 5.5 West Metro Regional Water Distribution Infrastructure.............................................................43

Figure 5.6 West Metro Regional Water Hydraulic Strategy........................................................................46

Figure 6.1 Capital Cost Summary Potential Savings................................................................................49

Figure 6.2 Average Customer Water Bill – 5,000 gallons/month, Current Water Bill.................................54

Figure 6.3 Average Customer Water Bill, All Go Alone...........................................................................55

Figure 6.4 Average Customer Water Bill, All Communities Stay Together..................................................56

Figure 6.5 Potential Project Capitalization..............................................................................................57

TABLESTable 1.1 Population Projections.............................................................................................................4

Table 3.1 MGD Purchase Capacity by West Metro Community................................................................17

Table 3.1 Existing Water Storage and Pumping Asset Inventory..................................................................21

Table 4.1 Population Projections...........................................................................................................24

Table 5.1 Peak Day Raw Water Supply Source Capacities......................................................................34

Table 5.2 Peak Day Finished Treatment Capacities.................................................................................36

Table 6.1 Capital Cost Summary..........................................................................................................48

Table 6.2 DWSRF Construction Loan and Financing Alternative...............................................................50

Table 6.3 Projected Regional Capital Fund............................................................................................52

WEST METRO REGIONAL WATER 1

1.0 EXECUTIVE SUMMARYDes Moines Water Works (DMWW) and several Des Moines Metropolitan Area communities have met over the past several years to explore the possibility of creating a regional drinking water governance structure, much like the current WRA structure of the sanitary sewer system. Several of the suburban communities feel they have no representation or say in how DMWW allocates costs, makes capital investments, and manages drinking water policy decisions. These communities rely on DMWW for some or all of their drinking water, and they would like a “seat at the table” and a voice in the decision making. If the metro communities cannot reach an agreement with DMWW and provide their customers an ability to have an impact in these decisions, they feel forced to look at options where they have more control over the future of their water supply and costs.

This report provides a framework where multiple western Des Moines suburban communities can work together to provide safe and reliable drinking water. This report has outlined the following:

1. There is an adequate supply of water, and it is physically possible to regionalize the western Des Moines metro system independent of the rest of Des Moines and its suburban communities.

2. It is cost effective and financially feasible for the western communities to regionalize their water systems.3. There are economies of scale and cost savings in working together. The more communities stay together

and make decisions mutually beneficial to the region, the more potential there is to reduce the overall costs.4. There is 93.0 MGD of water capacity available in the western region not including DMWW. This is enough

water to serve the six (6) participating communities, or a customer base of nearly 400,000 people. This satisfies the projected demand for the entire planning area through the year 2050.

5. DMWW provides 35.35 MGD of purchase capacity to the planning area communities today. Depending on the per capita peak day water demands and which communities participate, DMWW purchase capacity may or may not be required to serve the planning area.

1.1 B AC KG R O U N D

The following stakeholder communities joined together and engaged McClure Engineering Company to evaluate the technical feasibility of creating a West Metro Regional Water (WMRW) system.

• Adel• Grimes• Urbandale Water Utility

• Van Meter• Waukee• West Des Moines Water Works (WDMWW)

Figure 1.1 illustrates the WMRW planning area. The darker shaded areas for each community reflect the existing community boundaries or city limits. The lighter shaded areas reflect the anticipated growth over the study’s planning horizons. These anticipated growth areas were identified from existing comprehensive and/or land use plans. While the six communities listed above actively participated in the study, the communities of Clive, De Soto and Johnston were also included in our analysis. These cities were included based on proximity to the participating communities and the potential for those communities to increase the economies of scale if all communities worked together. Planning horizons of 10, 20 and 40-years were used to forecast population growth and water demands.


WAUKEE

ADEL

URBANDALE

WEST DES MOINES

VAN METER

GRIMES

DES MOINES

DE SOTO

DALLAS CENTER

CLIVEWINDSORHEIGHTS

I-80 I-35

I-235

I-80 / I-35

CUMMING

JOHNSTON

Figure 1.1West Metro Regional Water

Water Service Planning Area (2020)


1.2 P R O J E C T I O N S

Table 1.1 presents population projections of the stakeholder communities for each planning horizon. In 2060, the total population of the planning area communities is forecasted to be 517,315 and is based on past trends and data assimilated from the DMWW, MPO, City Comprehensive Plans and the US Census Bureau. This is consistent with growth trends in this area over the past 20 years. McClure worked with each community to determine the appropriate growth projections through 2060.

The DMWW 2040 Long Range Plan identified a projected annual average population growth rate of 1.77%, resulting in a 2060 population projection of 397,049 for the West Metro planning area. In the same study, peak day demand per capita was estimated at 226 gallons per capita per day (GCPD). Applying these factors results in a peak day demand of 90.36 MGD. We agree it is prudent to apply a high range and low range on population growth and subsequent water demands. However, we feel the factors DMWW have used are too low. We feel a low range estimate factor on the population growth rate of 2.0% per year is more prudent. A 2.0% annual growth rate results in a 2060 population projection of 439,504 for the West Metro planning area.

Daily per capita usage data was also gathered and evaluated for the study. The weighted average daily usage over the planning area was 104 GCPD. Peak daily water usage was calculated at 235 GCPD. Following presentation of average and peak day demands of the planning area communities to the stakeholder group, it was agreed the recommended values of 120 GCPD would be used for average day demand and 240 GCPD would be used for peak day demand across the planning area. Therefore, these value were used throughout this study.

As shown in Figure 1.2, using the recommended population projection of 517,315 and the recommended peak day water demand of 240 GCPD results in a 2060 peak day water demand of 124.16 MGD. This projection is approximately 38% higher than the DMWW Long Range Plan projected peak day water demands.


Table 1.1 Population Projections


2015 2020 2030 2040 2060Average Daily Demand 21,633,960 25,059,840 31,861,440 39,878,760 62,077,800Peak Daily Demand 43,267,920 50,119,680 63,722,880 79,757,520 124,155,600DMWW Long Range Plan 40,743,958 44,514,170 53,133,497 63,421,794 90,360,530West Metro Regional Plan 43,267,920 50,119,680 63,722,880 79,757,520 124,155,600Population 180,283 208,832 265,512 332,323 517,315

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128.35 MGD

93.00 MGD

Water Capacity with DMWW

Water Capacity without DMWW

Figure 1.2 Population and Daily Water Demand Projections


1.3 S U P P LY, T R E AT M E N T A N D H Y D R A U L I C ST R AT E G Y

Figure 1.3 illustrates the peak day water demand overlaid on the water supply and treatment capacities that can be developed in the WMRW area. There is the potential to develop 93.0 MGD of water supply and treatment in the WMRW planning area. This water supply capacity could serve the planning area, without DMWW purchase capacity, to a population of approximately 400,000 people. Existing DMWW purchase capacity is 35.35 MGD and would be necessary to meet the full 2060 projected demands if 240 GCPD peak day demand is realized and all planning area communities are included.

Several source water supplies were identified and combined with appropriate water treatment facilities to supply and treat the 93.0 MGD of peak day capacity. Included in this is 21.0 MGD of peak day ASR production capacity. Hydraulic modeling confirmed the infrastructure required to maintain water distribution and storage requirements. The cost to build 93.0 MGD of water supply, treatment, storage and distribution is estimated at $547.5 million. Included within this estimate is $82.5 million of water storage facilities. The cost without water storage facilities included is $465.0 million.

Figure 1.4 illustrates the overall hydraulic strategy for the WMRW area.


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Gal

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WDMW/WAUKEE

URBANDALE

ADEL

GRIMES

WARD

DMWW

West Metro Regional Plan

DMWW Long Range Plan

128.35 MGD

93.00 MGDWater Capacity without DMWW


Figure 1.3 Peak Water Demand and Water Treatment Capacities


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DMWWSTORAGE

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ADEL WTP

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WAUKEE

ADEL

URBANDALE

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VAN METER

GRIMES JOHNSTON

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DE SOTO

DALLAS CENTER

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EXISTING AND REQUIREDINFRASTRUCTURE

PROPOSED INFRASTRUCTURE FORADDITIONAL SYSTEM REDUNDANCIES

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WEST METRO REGIONAL WATERHYDRAULIC STRATEGY


Hydraulic Strategy


1 . 4 P H A S I N G A N D F I N A N C I N G

Financing of the capital costs was based on current State Revolving Loan Fund terms for drinking water loans, 2.0% interest for 20 years with a 10% coverage ratio on debt service payments. A phased financing strategy was developed based on demand growth and the most likely implementation of the proposed improvements. The phasing and financing model indicated a required capital cost fee of $1.00 per 1,000 gallons of water sold would be necessary. For an average customer of 5,000 gallons of usage per month, this would equate to a cost of $5.00 per month. The current monthly water bill for an average customer and the proposed monthly water bills are compared with other metro communities in Figures 1.5 and 1.6. The dark blue communities shown in the figures reflect those six communities who participated in the study. This data was based on 2019 water rate information available.

Operational and maintenance (O&M) costs were projected to be $1.50 per 1,000 gallons of water sold. This is based on the costs to supply, treat and provide bulk water to each individual community. This is similar, and was intended to be comparable, to other bulk water supply costs. It is expected each individual water utility would have additional costs for local utility needs similar to how they currently operate.

With an anticipated capital cost fee of $1.00 per 1,000 gallons and O&M fee of $1.50 per 1,000 gallons, the total bulk water cost would be $2.50 per 1,000 gallons. As reflected in Figure 1.6 only the $1.00 per 1,000 gallon capital cost fee was added to the existing rate structure. Our analysis indicated the six communities had an existing O&M cost, to provide bulk water to the individual communities, in excess of the proposed $1.50 per 1,000 gallons. Therefore, adding the O&M cost on top of the existing rate would result in double counting these expenses.

Our analysis identified ways to save on capital and O&M costs over time. These savings are highly dependent on the final participating communities and how they collectively choose to manage and operate the system. A potential of $107.5 million in capital cost savings was identified. This equates to 20% or a $0.20 per 1,000 gallons savings on the capital cost fee required. A potential O&M cost savings of $0.30 per 1,000 gallons was also identified. If both these cost savings were realized, the $0.50 per 1,000 gallons would reduce the bulk water cost to $2.00 per 1,000 gallons.

If realized, the potential O&M savings equates to more than $200.0 million in total savings through 2060. These savings have the greatest return potential if all communities work together, making decisions based on the greatest mutual benefit of the system.


Figure 1.5 Average Customer Water Bill – 5,000 gallons/month

Current (2019) Water Bill


Figure 1.6Average Customer Water Bill – 5,000 gallons/month

Proposed Water BillAll Communities Stay Together


1.5 R E COM M E N DAT I O N S

There is a growing need for additional water supply in the western Des Moines Metro. Currently Adel and Grimes are under construction on their own water supply and treatment facilities that will provide 4.2 MGD of additional capacity. Their current water demands require this capacity growth and this study included their respective projects and costs in the overall plan. Urbandale Water Utility has completed a study to expand treatment capacity by 20.0 MGD. Van Meter, Waukee and West Des Moines Water Works are in the final planning stages of their own joint treatment facility that would add an additional 21.0 MGD of finished water capacity to the region over time. Each of these projects are included in our analysis. These expansions should continue to be explored as the collective analysis is completed and each of the options are finalized.

The cost of this plan should be weighed by each member community against other proposed plans. We recommend looking at the benefits on a long-term horizon (20-40 years) as well as the long-term benefits of investing in capital improvements over the 40 plus year useful life of those improvements. Operational cost structures should not be minimized as they have a significant impact on rates over time.

This study was not intended to stop or slow any community from implementing water system improvements. Our analysis concludes it is possible to develop the water supply and distribution system to create a western regional water system. The cost to supply, treat and distribute the bulk water in the region is estimated at $2.00 to $2.50 per 1,000 gallons of water.

Should the stakeholders wish to explore forming a regional water system, the next step would be to continue the technical and governance discussions on how to best structure the regionalized system.


2.0 INTRODUCTION/PURPOSE2.1 G E N E R A L I N F O R M AT I O N

For the past several years, there have been many discussions with Des Moines Water Works (DMWW) and several of the Des Moines metro area communities about regionalizing the Des Moines area drinking water systems. Negotiations have stalled out for various reasons, including how to share the common asset costs and how the organization should be governed. DMWW has primarily led these discussions with proposals presented to the suburbs, but no agreements have been made as of the writing of this report. Several of the suburban communities feel they have no representation or say in how DMWW allocates costs, makes capital investments, sets other drinking water policies, and makes decisions. The absence of representation in the decision making process has led these communities to look at other options for their long-term water supply.

2.2 P U R P O S E OF T H E ST U DY

The purpose of this study was to inventory the existing and planned drinking water assets in the planning area. Based on those assets, the consultant would explore the technical feasibility of the stakeholder communities to create a regional approach to drinking water supply, treatment, storage, and distribution. This study was to forecast population growth and associated water demands over a 40-year planning horizon to determine if there is adequate raw water supply in the region. This study seeks to identify a long-term water supply and treatment strategy for the West Metro area that does not rely on the purchase of treated water from DMWW.

2.3 STA K E H O L D E R S

On July 18, 2019, the following west metro area community stakeholders met to discuss alternative ways in which they could continue to grow the water supply to serve their customers.

• Adel• Grimes• Urbandale

• Van Meter• Waukee• West Des Moines

Most of the stakeholders were in various stages of planning and or building their own water supply and treatment facilities when they met. While the stakeholders do not intend to rule out further discussions with DMWW, they felt it was important to further evaluate what options may exist to supply and treat water from sources other than DMWW on a regional basis. For that reason, they engaged McClure Engineering Company of Clive, Iowa to prepare a preliminary Drinking Water Master Plan for the area.

In addition to the communities identified above, this study looked at the communities adjacent to the existing stakeholders too. The below communities were included in this study to analyze the ability to achieve additional economies of scale and to eliminate the potential for competition of future resources.

• Clive• Johnston• De Soto


2.4 ST U DY A R E A

The West Metro planning area included in this study is illustrated in Figure 2.1. This area is generally bounded by the Des Moines River Valley and the City of Des Moines on the east, with natural terrain areas forming the northern, southern, and western boundaries. It includes the stakeholder communities listed previously along with Clive, De Soto, Johnston, and unincorporated areas in Dallas, Madison, Polk, and Warren Counties between the cities. Clive, DeSoto and Johnston did not participate in the study; however, their geographic area, population and water demands were included in the analysis. The Raccoon River Valley runs through the project area. Reasonable growth limits were placed on the planning area, but generally encompassed the anticipated future land use and comprehensive planning areas outlined by the individual communities.

2.5 O T H E R ST U D I E S

Water supply, treatment, storage, and distribution systems can easily last 40 years or more. When planning long-term major water infrastructure systems, it is typical to forecast water demands and plan for infrastructure to meet those demands over the 40-year planning horizon. The planning horizon for this study is from 2020 through 2060.

WATER STUDIES PERFORMED BY COMMUNITIESEach of the participating communities provided data and reports to support our analysis of the existing raw water supply, existing treatment and storage facilities, including:

• “Water Supply and Treatment Preliminary Engineering Report, Urbandale Water Utility, December 2013”, completed by McClure Engineering Co.

• “Report on Joint Water Quality Study, City of De Soto, Iowa, City of Van Meter, Iowa, March 2013”, completed by Veenstra & Kimm, Inc. and Bartlett & West Inc.

• “Report on Future Water Demands and Alternatives Evaluation, West Des Moines Water Works, August 2015”, completed by Veenstra & Kimm, Inc.

• “2016 Water System Study Design Report, Clive, Iowa, December 2, 2016”, completed by Snyder & Associates, Inc.

• “Municipal Raw Water Supply & Water Treatment Plant Evaluation: Preliminary Engineering Report, Adel, Iowa, January 2017”, completed by McClure Engineering Co.

• “Report on Joint Waukee/WMDWW Source Water Availability Study Task 1 and Task 2, May 2017”, completed by Veenstra & Kimm, Inc.

• “DMWW 2040 Long Range Plan, dated September 2017”.• “Water System Facility Plan, Grimes, Iowa, November 2017 (Revised May 2018)”, completed by FOX

Engineering.• “Report on Joint Waukee/WMDWW Source Water Availability Study Task 3 and Task 4, March 2018”,

completed by Veenstra & Kimm, Inc.

Additionally, this study uses data from the below report to support analysis of the Jordan Aquifer.

• “Cambrian-Ordovician Aquifer Sustainability Study in the Des Moines Metropolitan Area”, completed by Iowa Geological Survey and IIHR - Hydroscience and Engineering, University of Iowa.

This information, combined with recent supplemental data, were used by McClure to provide a comprehensive raw water supply strategy.


WAUKEE

ADEL

URBANDALE

WEST DES MOINES

VAN METER

GRIMES

DES MOINES

DE SOTO

DALLAS CENTER

CLIVEWINDSORHEIGHTS

I-80 I-35

I-235

I-80 / I-35

CUMMING

JOHNSTON


Water Service Planning Area (2020)


3.0 EXIST ING WATER TREATMENT AND DEL IVERY ASSETS3.1 WAT E R S U P P LY

As of the time of this study, the West Metro Region cumulatively produces 20.22 MGD of finished water. This amount includes 8.90 MGD from the Jordan Aquifer, 7.60 MGD from shallow alluvial wells and a Peak Day supply of 3.72 MGD via Aquifer Storage and Recovery (ASR).

Additionally, the West Metro Region retains purchase capacity of 35.35 MGD per day from DMWW. The communities of Clive, Johnston, Urbandale and Waukee currently receive all their water supply from DMWW while West Des Moines currently purchases water from DMWW in addition to producing their own water at AC Ward Treatment Plant. The communities of Adel, Grimes, De Soto and Van Meter currently provide water to their customers individually. In total, the current Peak Day finished water demand is 50.12 MGD. The West Metro Region is able to produce an excess of 5.45 MGD based on current demands and finished water supply.

3.2 T R E AT M E N T ASS E T S

The West Metro region has a vast network of pipes to transport water from water sources to various treatment plants. This section will review some of the existing water treatment plants. The existing treatment assets are in various stages of their service life. Several treatment facilities are new, while others retain significant years of remaining useful life. For the purposes of this study, it is assumed existing assets will be maintained or replaced as needed to support their current output through the 40-year planning horizon. Should assets need to be repaired or replaced, the financial responsibility will fall on the community the asset serves.

ADEL WATER TREATMENT PLANTThe Adel Water Treatment Plant collects water from shallow alluvial wells along the Raccoon River. The treatment plant is located at 208 N 5th Street in Adel. A new plant is currently under construction and will allow a maximum capacity of 2.4 MGD when finished.

GRIMES WATER TREATMENT PLANTThe Grimes Water Treatment Plant collects water from the Jordan Aquifer and shallow alluvial wells along Beaver Creek. The treatment plant is located at 1801 N James Street in Grimes. This plant has planned improvements scheduled which will produce a maximum capacity of 8.3 MGD when finished.

AC WARD WATER TREATMENT PLANTThe AC Ward Water Treatment Plant collects water from both the Jordan Aquifer and shallow alluvial wells along the Raccoon River. The treatment plant is located at 1505 Railroad Avenue in West Des Moines. This plant has a maximum capacity of 10.0 MGD.

VAN METER WATER TREATMENT PLANTThe Van Meter Water Treatment Plant collects water from shallow alluvial wells along the Raccoon River. This plant has a maximum capacity of 0.4 MGD. This plant is aging and is unable to meet the immediate and long term plans of the community. The plant is planned to be replaced by a new joint use facility shared with Waukee and WDMWW.


DE SOTO WATER TREATMENT PLANTThe De Soto Water Treatment Plant collects water from shallow alluvial wells along the Raccoon River. The treatment plant is located at 3345 Overton Circle in De Soto. This plant has a maximum capacity of 0.3 MGD. De Soto has improved the facility in recent years and the plant has significant useful remaining life.

3.3 D E S M O I N E S WAT E R WO R KS P U R C H AS E CA PAC I T Y

As mentioned in Section 3.1, the West Metro region purchases a total of 35.35 MGD from DMWW. The breakdown of MGD purchase capacity by West Metro community can be seen below in Table 3.1.

For this report, the total purchase capacity is rounded to 35.35 MGD.

3.4 P I P I N G N E T WO R K

Figure 3.1 illustrates the existing core water transmission lines that could be a part of the “common assets” of a regional supply. These lines are needed to carry large volumes of water to each service zone. A 30-inch line running generally east and west along Hickman Avenue from DMWW to the LP Moon Facility is the only existing major transmission line in the area. From LP Moon Storage Tank and Booster Stations, water is transmitted to the Urbandale West Tower where Xenia Rural Water District takes water northwest to Dallas Center. Additionally, water is transmitted to Clive and Waukee. Waukee recently has amended its purchase agreement and improved its infrastructure to be able to purchase water off this main. A 16-inch water line owned by Xenia Rural Water District transmits water from LP Moon west to Adel, south to De Soto, and then further west until it terminates in Menlo, Iowa. Additionally, Johnston and Urbandale purchase water from the DMWW core network via the Tenney/Merle Hay Road Ground Storage Reservoir and Booster Station. DMWW has provided Johnston a second connection along NW 66th via the Saylorville WTP. Clive has an eastern connection to the DMWW core network near 63rd and University. WDMWW has multiple connections with DMWW and primarily utilizes connection points at the AC Ward WTP, Army Post Road and the DMWW Core Infrastructure along 88th Street via the DMWW McMullin WTP.

Each community has their own water distribution system. As with the treatment assets, a physical condition assessment of existing piping networks was not included as part of this study. This would require further study to determine if they need to be replaced or rehabilitated over the 40-year planning horizon at the expense of the community the asset serves.

Clive 6.98 MGDUrbandale 15.3 MGDWaukee 4.0942 MGDWest Des Moines 8.973 MGDTotal 35.3472 MGD

Table 3.1MGD Purchase Capacity by West Metro Community


3.5 P R E SS U R E ZO N E S

Pressure zones are defined as an area bounded by an upper and lower elevation, all of which receive water from a given hydraulic grade line (HGL) or pressure from a set water surface. The WMRW planning area experiences a range of ground surface elevations ranging from below 900 feet along the Raccoon River basin to over 1060 feet at points along County Highway 58 between 312th St and 330th St in Adel. The topography of the study area is shown in Figure 3.1.

Using the topography, existing piping networks, water distribution zones, physical corporate boundaries of each community, shared used facilities and natural terrain boundaries of the entire West Metro Regional Water service planning area, McClure Engineering Company identified five (5) pressure zones. These zones keep operating pressures within acceptable ranges. A sixth pressure zone for the City of Johnston based on their existing infrastructure was identified should they choose to become an active WMRW stakeholder. These pressure zones are consolidated and illustrated on Figure 3.2. Based on these proposed pressure zones, most of the existing water storage assets in each community could remain in service with minimal impacts.

3.6 WAT E R STO R AG E

Each of the communities provided data and reports to support the analysis of the existing storage facilities. The WMRW service area is served by a combination of ground storage reservoirs and elevated storage tanks. The physical condition of existing water storage assets was not included as part of this study. More analysis may be required to determine if they need to be replaced or rehabilitated over the 40-year planning horizon at the expense of the community the asset serves. A summary of the existing storage facilities can be found in Table 3.1. These storage facilities are also shown in Figure 3.1.


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URBANDALE

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West Metro Regional WaterExisting Infrastructuremaking lives better

Less Than 900'

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950' - 1,000'

1,000' - 1,050'

1,050' - 1,100'

Greater than 1,100'

DMWW CORE NETWORKAQUIFER STORAGE AND RECOVERYBOOSTER STATIONWATER TOWER

LEGEND

Figure 3.1West Metro Regional Water Existing Core Infrastructure


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WEST METRO REGIONALWATER SERVICE ZONESmaking lives better

LEGEND

1190 HWL

1150 HWL

1145 HWL

1110 HWL

1075 HWL

JOHNSTON SERVICEZONE

1.75 MGD(3.50 MGD)

14.08 MGD(28.16 MGD)

5.26 MGD(10.52 MGD)

5.43 MGD(10.86 MGD)

7.51 MGD(15.03 MGD)

13.09 MGD(28.19 MGD)

0.38 MGD(0.76 MGD)

4.91 MGD(9.82 MGD)

3.37 MGD(6.75 MGD)

1.18 MGD(2.36 MGD)

0.97 MGD(1.94 MGD)

1.54 MGD(3.08 MGD)

Figure 3.2Proposed Pressure Zones


UUttiilliittyy LLooccaattiioonn TTyyppee RReeppoorrtteedd CCaappaacciittyy ((MMGGDD))

Adel New WTP GSR Ground Storage 0.75Low Zone EST Elevated Storage 0.25High Zone EST Elevated Storage 0.20WTP GSR Booster Pump Station 2.40South 14th Street Booster Pump Station 0.50

Grimes WTP Ground Storage 0.401st Street & James Elevated Storage 1.00New Water Tower Elevated Storage 1.501st Street & James Booster Pump Station 2.40

Urbandale 114th Street & Douglas Elevated Storage 1.00169th Street & Meredith Elevated Storage 1.00104th & Douglas Booster Pump Station 1.32

Van Meter Ground Storage Tank Ground Storage 0.04Elevated Storage Tank Elevated Storage 0.10Booster Pump Station Booster Pump Station 0.24

Waukee 3rd Street Elevated Storage 0.5098th Street Elevated Storage 0.50

West Des Moines WTP GSR #1 Ground Storage 1.00WTP GSR #2 Ground Storage 2.0039th Street & Ashworth Road Ground Storage 0.7517th Street & Ashworth Road Elevated Storage 0.5039th Street & University Elevated Storage 1.0050th Street & Mills Civic Elevated Storage 2.0088th Street Elevated Storage 2.0098th Street Elevated Storage 1.0088th Street (Zone 4) Booster Pump Station 5.76S. 22nd Street Booster Pump Station 4.5688th Street (zone 3) Booster Pump Station 3.60Westown Booster Pump Station 1.44Fuller Road Booster Pump Station 2.4039th Street Reservoir Booster Pump Station 4.0250th Street Booster Pump Station 1.92Grand Avenue Booster Pump Station 2.16Alluvion Booster Pump Station 3.50

Clive University Avenue (East) Elevated Storage 0.50University Avenue (West) Elevated Storage 1.2098th Street Elevated Storage 1.007820 University Avenue Booster Pump Station Unknown

Note: Booster pump station capacity based on 20 hour operation.

TTaabbllee 33..11 -- EExxiissttiinngg WWaatteerr SSttoorraaggee aanndd PPuummppiinngg AAsssseett IInnvveennttoorryy

Table 3.1Existing Water Storage and Pumping Asset Inventory


4.0 POPUL ATION, CURRENT WATER DEMANDS AND FORECASTED GROWTH4.1 R E G I O N A L P O P U L AT I O N

CURRENT POPULATIONPopulation data was obtained from WMRW communities, the Des Moines Metropolitan Planning Organization, US Census Bureau, and a compilation of data from the DMWW as part of the Central Iowa Drinking Water Commission (CIRDWC). As of 2015, the WMRW planning area population was approximately 180,000. In 2020, the projected population is expected to near 210,000.

PROJECTED POPULATIONIn developing future population estimates, proposed population projections were analyzed and benchmarked against historical population trends in the region. Growth trends were then benchmarked against land areas available for growth and traditional population densities of similar communities. Existing and proposed land uses were used in these calculations. Figure 4.1 illustrates current City Limits compared to projected future City Limits to account for population growth.

McClure population forecasts were presented to each of the stakeholder communities and presented collectively to the group. Aggregated population trends are similar to the growth area and are representative of communities of similar size. Following presentation of population projections, the stakeholders concluded to use a 2.0-2.5% aggregate population growth per year. Applying these growth projections over the 40-year planning horizon results in a population estimate between 440,000-517,000 for the WMRW planning area by 2060. We recommend planning infrastructure to accommodate the high range population growth.

The DMWW 2040 long range plan projects an estimated population growth of 1.77% per year. This estimate is below the low-end range used by McClure in our analysis and may lead to an underestimation of the West Metro Region’s water demands. Therefore, it is not recommended to be used as a planning metric, even as a low-end range estimate.

Table 4.1 illustrates the current and projected population trends over the next 40 years.


WAUKEE

ADEL

URBANDALE

WEST DES MOINES

VAN METER

GRIMES

DES MOINES

DE SOTO

DALLAS CENTER

CLIVEWINDSORHEIGHTS

I-80 I-35

I-235

I-80 / I-35

CUMMING

JOHNSTON

Figure 4.1Existing (2020) and Projected City Limits


Table 4.1Population Projections


Service Area Population Projections835,342

538,312

Figure 4.2DMWW Metro Population Projections

*From DMWW 2040 Long Range Plan


4.2 WAT E R D E M A N D S

CURRENT WATER DEMANDSHistorical water demands were analyzed for each of the planning communities. Demands were tabulated and aggregately projected across the planning area. Trends in the industry were benchmarked along with trends in the planning area. Projections were represented as a per capita value for average day and peak day demands. Figure 4.3 illustrates average and peak demands for each of the nine communities and the aggregated averages on a per capita per day basis. The aggregated average day demand was 104 gallons per capita per day. The aggregated average peak day demand was 235 GCPD.

Figures 4.4 and 4.5 represent the projected average day and peak day water demands for the Metro identified in the DMWW Long Range Plan. A peak day demand factor of 226 GCPD can be calculated by comparing Figure 4.5 and Figure 4.2 (189 MGD / 835,342 people = 226 GCPD).

PROJECTED WATER DEMANDSAfter presenting the current demands to the planning group, it was agreed the recommended values of 120 gallons per capita per day for average day demand and 240 gallons per capita per day for peak day demand would be used across the planning area. Due to the pace and variability of the population growth in the area, it was agreed the per capita demand values would be multiplied by the population projections to obtain the necessary total water demands for the region.

Using the projected population of 517,315 and the peak day demand of 240 gallons per capita per day, the total peak day water demand in 2060 is projected to be 124.16 MGD. This projection is 34 MGD higher, approximately 38% higher, than the DMWW Long Range Plan estimates. This difference can be seen on Figure 4.6. McClure’s 2.0% low range population estimate of 439,504 results in a peak day water demand of 105.5 MGD. This is still 15 MGD higher or approximately 17% greater than the DMWW assumptions. These demand projections are a function of population growth projections and future trends in water usage/demand. It is our recommendation when conducting water system planning for the WMRW area, projections of future demands should be based on the high range values. WMRW planning area demand projections are summarized in Figure 4.7.


Figure 4.3Per Capita Water Demands by Community


Projected Average Day Demand

55

87

Figure 4.4DMWW Projected Metro Average Day Demand



Projected Max Day Demand

116

189

Figure 4.5DMWW Projected Metro Peak Day Demand



2015 2020 2030 2040 2060West Metro Regional Plan 43,267,920 50,119,680 63,722,880 79,757,520 124,155,600DMWW Long Range Plan 40,743,958 44,514,170 53,133,497 63,421,794 90,360,530

Population 180,283 208,832 265,512 332,323 517,315

-

100,000

200,000

300,000

400,000

500,000

600,000

-

20,000,000

40,000,000

60,000,000

80,000,000

100,000,000

120,000,000

140,000,000

Popu

latio

n

Peak

Day

Wat

er D

eman

d (g

pd)

128.35 MGD

93.00 MGD

Figure 4.6Population Projections and Peak Day Water Demand




2015 2020 2030 2040 2060Average Daily Flow 21,633,960 25,059,840 31,861,440 39,878,760 62,077,800Peak Daily Flow 43,267,920 50,119,680 63,722,880 79,757,520 124,155,600DMWW Long Range Plan 40,743,958 44,514,170 53,133,497 63,421,794 90,360,530West Metro Regional Plan 43,267,920 50,119,680 63,722,880 79,757,520 124,155,600Population 180,283 208,832 265,512 332,323 517,315

-

100,000

200,000

300,000

400,000

500,000

600,000

-

20,000,000

40,000,000

60,000,000

80,000,000

100,000,000

120,000,000

140,000,000

Popu

latio

n

Dai

ly F

low

(gpd

)128.35 MGD

93.00 MGD

Figure 4.7Population and Daily Water Demand Projections




5.0 P R O P O S E D F U T U R E I N F R AST R U C T U R E TO M E E T P R O J E C T E D D E M A N D S5.1 WAT E R S U P P LY

As part of the overall hydraulic strategy, McClure identified a balanced supply of water sources for the region to meet the forecasted water demands. Developing multiple raw water sources creates a robust operations scenario. McClure has identified the potential raw water sources below:

• Deep Wells• ASR Wells

• Shallow Alluvial Wells• Surface Water Ponds

JORDAN AQUIFER – DEEP WELLS AND ASR WELLSAs an extension of the McClure analysis, and in conjunction with the greater Polk County Jordan Aquifer study currently underway by the State of Iowa, the planning group engaged the Jordan Aquifer study group to look at the collective Jordan Aquifer raw water supply available and the combined ability to use the Jordan Aquifer for Aquifer Storage and Recovery (ASR).

The supplemental study indicated the Jordan Aquifer could supply up to 10 MGD of raw water, while at the same time, utilize the Jordan for an additional 27.0 MGD of ASR production. For our analysis, McClure used 21.0 MGD of ASR production and reserved the remaining potential capacity until future testing and usage can be verified.

The proposed 10.0 MGD of Jordan raw water supply was allocated to the Grimes WTP and the existing WDM WW AC Ward WTP. These two plants currently utilize raw water from the Jordan and remain to be the least impacted from future ASR production wells.

McClure’s Hydraulic Strategy maximizes the ASR production capacity by optimizing the spacing and use of those wells. Individually, communities would not be able to benefit from the optimized spacing nor the collective redundancy all the wells provide.

SHALLOW ALLUVIAL WELLSThe DMWW Long Term Plan identified a range of 38-63 MGD as an available water source from shallow alluvial wells. This should be investigated further to confirm feasibility of this recommendation. For the WMRW planning area, McClure has identified the following three locations for proposed Alluvial Wells.

• Raccoon River Wellfield – 6.5 MGD• Van Meter Wellfield – 6.5 MGD• Adel Wellfield – 12.0 MGD


SURFACE WATER PONDSThe WMRW planning area can support up to 28 MGD of water supply via surface water ponds. The below sources have been identified for future use.

• Urbandale Ponds (10.9/20.0 MGD)• Hallett Quarry (4.0 MGD)• I-80 Quarry (4.0 MGD)

In total, there is 93.0 MGD of finished water capacity available in the western region without utilizing purchase capacity from DMWW. This is enough finished water to serve the six (6) participating communities or a customer base of nearly 400,000 people. This satisfies the demand for the entire planning area through the year 2050. To satisfy the projected demand for the entire 40-year planning horizon, water may need to be purchased from DMWW or additional western water supplies would need to be identified and developed. Table 5.1 provides a summary of the raw water supply’s available for the planning area.


"Current"

2020 2030 2040 2060

Peak Day Finished Water Demand* 50.12 63.72 79.76 124.16

Identified Raw Water Sources

Jordan Aquifer 8.90 8.90 10.00 10.00

Grimes Shallow Alluvial 1.40 1.40 4.00 4.00

Adel Shallow Alluvial 1.20 2.40 8.40 12.40

DeSoto Shallow Alluvial 0.30 0.30 0.30 0.30

WDM Ward Shallow Alluvial 4.30 4.30 4.30 4.30

WDM/Waukee/VM Shallow Alluvial 0.40 6.50 6.50 13.00

Urbandale Ponds 0.00 8.00 12.50 20.00

Racoon River Ponds 0.00 0.00 8.00 8.00

Total Raw Water Supply 16.50 31.80 54.00 72.00

ASR Peak Day Supply 3.72 6.72 10.00 21.00

Total Raw Water & ASR Supply Capacity 20.22 38.52 64.00 93.00

Total DMWW Purchase Capacity 35.35 35.35 35.35 35.35

Total Supply with DMWW 55.57 73.87 99.35 128.35

Total Supply without DMWW 20.22 38.52 64.00 93.00

Excess/(Shortage)

With DMWW 5.45 10.15 19.59 4.19

Without DMWW (31.16)

*5% water loss accounted for through treatment process

Table 5.1Peak Day Raw Water Supply Source Capacities


5.2 T R E AT M E N T ASS E T S

McClure reviewed typical ground and surface water treatment technologies and conducted a desktop analysis of their suitability in the overall regional hydraulic strategy. A detailed analysis was not part of the scope of the study.

McClure generally reviewed the following treatment concepts:

• Direct Reverse Osmosis (RO)• Filtration followed by RO• Lime Softening

TREATMENT STRATEGY ALTERNATIVES1. Direct Treatment of Jordan Aquifer with RO

• Well established in Iowa• Lowest treatment and operational cost for hardness reduction• Blend water likely does not have to be treated for Fe/Mn removal• Not recommended for shallow alluvial wells because water quality can vary greatly, although can

be tested with pilot study. • Does not meet surface water treatment rules• Produces 15-20% RO Waste, likely has to be discharged to the sanitary sewer • Will satisfy needs for nitrate removal

2. Filtration (Fe/Mn removal) followed by RO for Groundwater Treatment• Can be used for shallow alluvial wells (not under influence of surface water) and Jordan wells• Could be used in conjunction with direct RO treatment for Jordan Wells• Better equipped to treat the variations in water quality within shallow alluvial wells• RO will satisfy needs for nitrate removal

3. Surface Water Treatment with Lime Softening• Matches DMWW treatment and water quality• Significantly less waste than RO, which is important in source-water limited areas• Would treat shallow alluvial (under influence of surface water) and surface pond water• Would need to accommodate nitrate removal needs

Examples of a Direct RO treatment schematic and a Lime Softening schematic can be seen in Figures 5.1 and 5.2, respectively. General sizing and cost estimating were included in our analysis. This work was used as the basis of the capital costs outlined in this report.

Based on McClure’s analysis, new treatment plants will be necessary to produce the required amounts of finished water as demand increases. Finished water quality was benchmarked based on historical water quality provided in the metro by DMWW & WDMWW. No major deviations were assumes as a part of the study, and the finished water quality is expected to be similar to the existing regional water supply.

Table 5.2 provides a summary of the proposed water treatment strategy for the planning area. A graphical representation of this strategy is found in Figures 5.3 and 5.4.


"Current"

2020 2030 2040 2060

Peak Day Finished Water Demand* 50.12 63.72 79.76 124.16

Water Treatment Assets (MGD)

WDWW Ward WTP 10.00 10.00 10.00 10.00

Grimes WTP 4.40 4.40 8.30 8.30

Adel WTP 1.20 2.40 2.40 2.40

Van Meter WTP 0.40 0.00 0.00 0.00

De Soto WTP 0.30 0.30 0.30 0.30

New Urbandale WTP (Lime Soften, Surface Water) 0.00 8.00 12.50 20.00

New Joint WTP (Lime Soften, Surface Water) 0.00 6.50 14.50 21.00

New Adel WTP (Filter/RO, Ground Water) 0.00 0.00 6.00 10.00

Total Finished Water Treatment Capacity (MGD) 16.30 31.60 54.00 72.00

ASR Peak Day Supply (MGD) 3.72 6.72 10.00 21.00

Total Finished Water & ASR Supply Capacity (MGD) 20.02 38.32 64.00 93.00

Total DMWW Purchase Capacity 35.35 35.35 35.35 35.35

Total Supply with DMWW 55.37 73.67 99.35 128.35

Total Supply without DMWW 20.02 38.32 64.00 93.00

Excess/(Shortage)

With DMWW 5.25 9.95 19.59 4.19

Without DMWW (31.16)

*5% assumed water loss through treatment process

Table 5.2Peak Day Finished Treatment Capacities


RO BYPASS

BAG FILTERSRAW WATER

JORDAN AQUIFER

CART.FILTERS

E

ANTI-SCALANT

BLEND CONTROLVALVE

PERMEATE

RO

RO CONCENTRATION TO DIRECT DISCHARGE OR SANITARY SEWER

POST-AERATION

FINISHED WATER TO HSP

COROSSION IN

HIBITOR

CAUSTIC

CHLORIN

E

DIRECT RO TREATMENT SCHMETIC

Figure 5.1Direct RO Treatment Schematic


LIME-SODA ASH SOFTENINGTREATMENT SCHEMATIC

Figure 5.2Lime Softening Schematic


WAUKEEADEL

URBANDALE

WEST DES MOINES

VAN METER

GRIMES

DES MOINES

DALLAS CENTER

CLIVEWINDSORHEIGHTS

I-80 I-35

I-235

I-80 / I-35

CUMMING

JOHNSTON

DESOTO

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4.d

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RAW WATER SUPPLY &WATER TREATMENTmaking lives better

EXISTINGADEL WTP2.4 MGD

NEW ADEL WTP12.0 MGD

I-80 QUARRY4.0 MGD

EXISTINGDESOTO WTP

0.3 MGD

EXISTING VANMETER WTP0.4 MGD

WELLFIELD6.5 MGD

WELLFIELD6.5 MGD

HALLETQUARRY4.0 MGD

EXISTINGGRIMES WTP8.3 MGD

NEW URBANDALE WTP20.0 MGD

URBANDALE PONDS10.9 MGD (200 CFS DES MOINES RIVER)20.0 MGD (175 CFS DES MOINES RIVER)

RAW WATER SUPPLYWATER TREATMENT

LEGEND

EXISTING WARD WTP 10.0 MGD

NEW JOINT WTP21.0 MGD

WELLFIELD12.0 MGD

Figure 5.3Proposed Raw Water Supply and Water Treatment


-

20,000,000

40,000,000

60,000,000

80,000,000

100,000,000

120,000,000

140,000,000

2020 2030 2040 2060

Gal

lons

per

Day

ASR

WDMW/WAUKEE

URBANDALE

ADEL

GRIMES

WARD

DMWW

West Metro Regional Plan

DMWW Long Range Plan

128.35 MGD

93.00 MGDWater Capacity without DMWW


Figure 5.4Water Treatment Strategy


5.3 P I P I N G N E T WO R K

It was determined that each community would provide and maintain their own local distribution system equivalent to having a 12-inch water main grid every one mile throughout the community. This would provide the modeler an equal base line for supplying and connecting the systems together. If deficiencies within a community limit the ability for this 12-inch grid to operate effectively, it would be good practice to correct this regardless of the regional model. Each community would budget for and correct any deficiencies, if necessary. The recommended Hydraulic Strategy provides redundancy to the communities and takes advantage of the benefits of common “core infrastructure” to benefit the region.

The consensus of the planning group was for each community to maintain local system autonomy within individual distribution systems. This minimizes the number of system interconnections and reporting requirements. This would also allow each community to maintain individual community customer service operations including customer billing.

By retaining local system autonomy, each community would have the flexibility on whether to participate without impacting the overall regional plan. Should a community initially decide to not participate in the regional plan, but later desire to be included, the community could be incorporated with no impact to the regional plan. The regional plan also allows for infrastructure upgrades to occur over time as it is not necessary that all proposed upgrades occur immediately.

5.4 WAT E R STO R AG E

Figure 5.5 illustrates the existing ground and elevated storage assets serving the area now via gray symbols. Blue symbols illustrate locations where elevated and ground storage assets could generally be placed to serve the area. To create and maintain the previously discussed pressure zones, it will be beneficial to share in water storage assets when possible. Shared water storage assets are also financially beneficial, as it is much cheaper to build one larger tower to serve multiple communities than for those communities to each build a smaller tower of their own. This must be balanced with the reliability and flexibility that comes from the redundancy of having adequate storage facilities spread throughout the service area. The proposed hydraulic strategy accomplishes this balance.

There are significant economies of scale in the construction, sizing and location of the proposed storage facilities. McClure developed a hydraulic strategy where these opportunities could be maximized throughout the planning area. As discussed in Section 3.4, water distribution pressure zones were identified using existing piping networks, existing water distribution zones, physical corporate boundaries of each community, existing shared used facilities and natural terrain boundaries in the planning area. Optimized tower elevations were developed and to the greatest extent possible, existing infrastructure was utilized.

A focus was placed on utilizing ground storage reservoirs in combination with the existing and proposed water treatment plants. Existing and proposed high service pumping facilities working in combination with ground storage is a cost-effective way of meeting required storage volumes for each water system.

Ground storage facilities operated in conjunction with booster pumping stations were included in the study analysis. When conditions allow, these combined facilities can be utilized to provide similar cost benefits to elevated storage. Appropriate back up power systems were planned for in the costs provided and allow for meeting applicable water standards.


Elevated storage was provided in all service zones and is the primary source for sustaining system pressures. There was significant dialogue concerning the extent storage facilities should be included as a part of the regional plan. Joint use water storage facilities, such as the joint use 98th Street Tower, have been used in the planning area and have functioned well. One could exclude these from the regional plan and leave it up to each community to implement. It is also important to note that the DMWW regional plan does not include individual community storage requirements in its Long Range Plan.

Storage facilities are required and need to be included as part of long-range planning. Consensus was built around their inclusion for the long-term benefits and economies of scale of the WMRW planning area. Including them in our evaluation added $82.5 million of additional capital costs to the regional plan. The inclusion of these assets needs to be considered when comparing the DMWW plan to the recommendations of this study.


WAUKEE

ADEL

URBANDALE

WEST DES MOINES

VAN METER

GRIMES

DES MOINES

DE SOTO

DALLAS CENTER

CLIVEWINDSORHEIGHTS

I-80

I-35

I-235

I-80 / I-35

CUMMING

JOHNSTON

WDM - SE 22nd Street Booster

WDM - Grand Ave. Booster

WDM - 50th Street Booster

WDM - Fuller Road Booster

WDM - Ward Treatment Plant

WDM - Westown Parkway Booster

WDM - 88th Street Booster

URB - Tenney Booster

LP Moon

URB - 104th & Douglas (Emergency)

WAK - Eason Elementary Booster

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WEST METRO REGIONAL WATER DISTRIBUTION INFRASTRUCTUREmaking lives better

REQUIRED DISTRIBUTION SYSTEMOPTIONAL DISTRIBUTION SYSTEMREQUIRED INTERSYSTEM CONNECTIONSOPTIONAL INTERSYSTEM CONNECTIONSOPTIONAL SYSTEM RELIABILITY

LEGEND

1.0

2.0

2.0

1.5

4.0

2.5

2.5

2.0

1.51.5

5.0

2.5

2.5

2.5

2.5

2.0

3.0

2.0

1.0

1.51.5

1.0

2.0

1.0 1.5

0.5

3.0

2.0

2.0

2.50.5

6.0

4.0

1.0

Figure 5.5West Metro Regional Water Distribution Infrastructure


5.5 H Y D R A U L I C ST R AT E G Y

The regional hydraulic strategy includes the following key aspects:

• System interconnections were modeled to maximize regional distribution, maintain system pressures, maximize shared water storage facilities and optimize system redundancy.

• Shared or regional booster pumping stations along with corresponding feeder mains would be “core infrastructure” and be a shared asset for the region.

• System redundancy is provided when possible and where it is reasonably cost effective. Redundancy takes advantage of the benefits of common “core infrastructure” to benefit the region.

• ASR production capacity is maximized by optimizing the spacing and use of ASR wells. Individually, communities would not be able to benefit from the optimized spacing nor the collective redundancy all the wells provide.

After hydraulic modeling was completed and optimized, a global “West Metro Regional Water Hydraulic Strategy” was developed. A macro summary of this strategy is depicted in Figure 5.6 and a proposed distribution piping network is illustrated on Figure 5.5.

There are areas where the existing infrastructure and the ability of the system to be isolated allows for more cost-effective delivery of water by DMWW. While the utilization of DMWW purchase capacity remains part of the long-range hydraulic strategy, these existing connections were maintained. The utilization of these connections will be dependent on the final members of the regional group.

As stated in Section 3.1, DMWW currently provides the entire water supply to the communities of Clive, Johnston, Urbandale, and Waukee. The communities of Grimes, Adel, Van Meter and De Soto entirely produce their own water. West Des Moines produces their own and purchases water from DMWW.

The modeling indicated Clive and Johnston could satisfy their needs long term through their existing DMWW connections. Due to recent improvements, Johnston could implement this with little impact and additional improvements. Though the infrastructure exists, Johnston does not have enough purchase water capacity under contract from DMWW to meet their future needs, and additional negotiation of purchase capacity may be required.

Clive has little opportunity to grow geographically and a significant increase in water demands is not anticipated. Clive currently has 5.8 MGD of purchase capacity from DMWW, and this appears to be adequate through the 2060 planning horizon. Clive has interconnections with DMWW that can be maintained with little or no impact to the other WMRW communities. Clive has an agreement with Waukee and WDM to share capacity in the 2.5 million gallon 98th Street elevated storage tank. If Clive were to be isolated from Waukee and WDM, minor improvements would be needed and an amendment to the agreement would be necessary. It is very probable Clive and Johnston could be removed from the West Metro Regional Water Plan with little impact on the rest of the communities.

Waukee would need to receive water from another entity regardless of the final WMRW membership group, and the City is actively exploring options with Van Meter and WDMWW. These and other community partnering efforts should continue. Waukee is in the unique position to partner with many planning area communities including Adel, Grimes, Urbandale, Van Meter and WDMWW in addition to DMWW.


Urbandale has the ability to meet its long-range needs through the construction of the Beaver Creek storage ponds and their own water treatment plant. Fully built, the Urbandale supply and treatment plant, would have the ability to provide a small amount of excess capacity to the region. In addition, Urbandale has the largest share of DMWW purchase capacity under agreement at 15.3 MGD of the 35.35 MGD. If the Urbandale plant is built, with its current DMWW purchase capacity, Urbandale could provide the region with approximately 18 MGD of excess capacity.

Grimes currently produces all its water demands via its own supply and treatment. The current planned capacity of 8.3 MGD will supply a population base of roughly 35,000 people and should meet Grimes’s needs through the year 2040. With 2060 water demands approaching 17 MGD they will need to find additional supply and treatment sources.

West Des Moines (WDM) currently has the ability to produce 10.0 MGD of water at the AC Ward WTP. When combined with its purchase capacity of 8.973MGD, WDM has nearly 19 MGD of finished water capacity. With a current peak day demand approaching 17 MGD, WDM has limited excess capacity and should continue to look for additional viable supply sources. WDM is actively exploring options of a joint use water facility with Van Meter and Waukee in addition to continued negotiations with DMWW. It is recommended WDM continue to look at multiple water supply and treatment options to meet their forecasted growth.

The communities of Adel, De Soto and Van Meter could remain independent with little impact to the rest of the distribution system given their existing autonomy. Adel can meet their forecasted water demands through the 2060 planning horizon and could provide excess capacity to the region.

De Soto has limited capacity to meet their long-term water demands under the existing structure and continuing in this manner is not recommended. De Soto should explore partnering opportunities with neighboring communities to accommodate their long-term needs.

Van Meter currently supplies its water demand via their own existing supply and treatment facilities. Existing infrastructure is aging and does not have the capacity to meet their growing water demands. Van Meter is actively exploring options of a joint use facility with Waukee and WDM. This appears to be the most viable long-term solution, and it is recommended Van Meter continue to explore this alternative.

Together, the regional planning area communities have a technically viable and cost-effective solution to meet future water demands through 2060. The identified hydraulic strategy includes maintaining the current level of purchase capacity from DMWW. However, the communities that currently hold rights to that purchase capacity are not necessarily the communities who need the capacity long term. This is the essence of working together and collaborating as a region. Working together optimizes available resources, minimizes/right sizes capital investments, and helps spread the cost of capital investments over a larger user base.


80

DMWWSTORAGE

PROPOSEDWDMWW / WAUKEE

WTP

DMWWMcMULLEN

WTP

PROPOSEDURBANDALE

WTP

ADEL WTP

WDMWWWARD WTP

GRIMESWTP

DMWWSAYLORVILLE

WTP

DMWW CORENETWORK

DMWW CORENETWORK

DMWW CORENETWORK

WAUKEE

ADEL

URBANDALE

WEST DES MOINES

VAN METER

GRIMES JOHNSTON

DES MOINES

DE SOTO

DALLAS CENTER

CLIVEWINDSORHEIGHTS

I-80 I-35

I-235

I-80 / I-35

CUMMING

WTP

WTP

WTP

WTP

WTP

WTP

WTP

EXISTING AND REQUIREDINFRASTRUCTURE

PROPOSED INFRASTRUCTURE FORADDITIONAL SYSTEM REDUNDANCIES

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.dw

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WEST METRO REGIONAL WATERHYDRAULIC STRATEGY

Figure 5.6West Metro Regional Water Hydraulic Strategy


6.0 F I N A N C I A L I M PAC T6.1 CA P I TA L CO ST S

In total, $547.5 million of capital investments have been identified to fully implement the plan, which includes $82.5 million of water storage facilities. As stated previously, the DMWW Long Range Plan does not include storage in the identified capital investments. In consideration of this, to provide direct comparison to the DMWW Long Range Plan, if storage is excluded from the WMRW plan, capital investments costs would decrease to $465.0 million. A summary of the total capital costs is listed in Figure 6.1.

As part of this analysis, McClure estimated the capital costs of all communities “going alone” as well as the capital costs of implementing optimization measures if “all stay together”. Our evaluation identified that if each community were to take the approach of “going alone”, it could add $42.5 million (or 7.8%) to the overall capital costs, increasing the total capital budget to $590 million. Conversely, additional system optimizations achieved when WRWA regional communities “all stay together” could reduce the total cost of the plan by over $107 million (or 19.5%), bringing the total capital budget to $440 million. A comparison of these options is illustrated in Figure 6.1.

Examples of potential cost saving measures are:

• Water Conservation Efforts• Increased Jordan Aquifer Supply• Increased ASR Production• Optimize System Redundancy Efforts• Phasing Plan Implementation

6.2 P H AS I N G I M P L E M E N TAT I O N

Funding nearly $550 million of capital investment at first appears to be a daunting and overwhelming endeavor. It is important to keep in mind these investments would serve over 500,000 people and occur over a 40-year period. Ultimately the most cost-effective hydraulic solution is to fully build out all proposed ASR facilities first, followed by required treatment facilities second. However, this approach is not necessarily practical or cost effective due to increased capital costs when inflation is included.

From a regional standpoint, infrastructure will be built in communities according to the demand as needed. From there, each treatment plant and the associated pumping and distribution infrastructure can be phased accordingly, when hydraulically feasible.

Phase I of each treatment plant will be the most expensive phase on a cost per gallon basis. It is hydraulically feasible to build Phase I of each treatment plant first and then subsequent phases later. Building out all phases of a single plant will be more cost effective. In some cases, this approach might be the most practical, in other cases it may not.


"Current"

2020 2030 2040 2060 Total

Peak Day Finished Water Capacities (MGD) 39.97 69.77 99.25 128.25 128.25

Water Treatment Facility Capital Costs $38.70 $60.50 $60.00 $164.60 $323.80

Aquifer Storage & Recovery Facility Capital Costs $6.00 $12.00 $18.00 $18.00 $54.00

Treated Water Storage Facility Capital Costs $4.00 $19.00 $29.00 $30.50 $82.50

Distribution/Interconnection Capital Costs $4.70 $37.50 $6.60 $38.40 $87.20

$53.40 $129.00 $113.60 $251.50

*All costs shown in 2020 dollars and reported in millions of dollars

Table 6.1Capital Cost Summary


Task 6 Meeting10/15/2019

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CAPITAL COST SUMMARY

Base Option$547.5M

System Autonomy$590M

Full Collaboration $440M

Figure 6.1Capital Cost Summary

Potential Savings


Similarly, once Phase I of a plant is built, pumping and distribution infrastructure will also need to be constructed. Again, due to the future sizing and economies of scale, it may be more cost effective to build out one distribution zone and then move to another distribution zone in the planning area.

This report has considered these factors and provided the most “probable” and “likely” phasing approach to be implemented.

6.3 S R F

McClure has assumed the Drinking Water State Revolving Loan Fund (DWSRF), as administered jointly by the Iowa Department of Natural Resources and the Iowa Finance Authority, will be obtained to finance the construction of the required infrastructure. Construction Loans offered by the DWSRF program can take the form of either a revenue bond or a general obligation bond. While each type of bond has the same loan terms and interest rates available, revenue bonds in the DWSRF program require a coverage ratio of 10%, which is lower than the typical 25% coverage ratio required by conventional water revenue bonds. General obligation bonds in the DWSRF program do not require a coverage ratio. The DWSRF program interest rates and fees are shown in Table 6.2.

Utilizing the DWSRF program, there are additional requirements added to the project, such as Davis-Bacon wages, American Iron & Steel requirements, and additional construction contract documents. The financing terms used as a part of our analysis are 2% interest for 20 years with a 10% coverage ratio on all debt service payments. These terms are consistent with recent SRF loans issued throughout the state. These financing terms have been in place for many years and are not anticipated to change in the foreseeable future.

6.4 I M PAC T TO C U STOM E R WAT E R R AT E S BY COM M U N I T Y

Future water demands, and the capital investments necessary to satisfy them, are highly dependent upon population growth of the West Metro region. As previously outlined, it is proposed to obtain capital financing through the DWSRF program. To meet the associated debt service requirements, an increase in utility rates will be necessary. In reviewing financing options with the stakeholder group, it was agreed to account for debt services expenses on a cost per 1,000 gallons sold basis. This methodology was used throughout our analysis.

As customer rate increases are undesirable, McClure took steps to evaluate options which would minimize the financial burden being passed to customers. From a regional perspective, the more the communities work together to spread capital investments, the less of an impact one single community will have in making a substantial investment. A single community will not be able to benefit from the economies of scale and potential cost savings the regional plan provides. This equates to a “double negative”; it drives up the capital cost of each project and drives up corresponding customer rates.

OPTIONORIGINATION

FEEINTEREST

RATE1

LOAN TERM

COMMENTS

Option 1 0.5% 2.00% 20 All Communities Eligible

Option 2 0.5% 3.00% 30Limited to the portions of project with a

design life exceeding 20 years.

Table 6.2DWSRF Construction Loan and Financing Alternative

1The loan administration/servicing fee of 0.25% has been included in all interest rates shown.


Should population grow as predicted, the larger customer base will drive increased demand, therefore increasing necessary capital investments required to satisfy the increased water demands. However, the more customers are added to the region, the more the associated costs can then spread to the growing number of customers. A larger population results in a lower cost per customer to offset the proposed infrastructure investments.

As outlined in Section 6.1, there is an estimated capital cost savings of $107 million if full collaboration is achieved. If all $107 million in savings were realized, a resulting debt service reduction of approximately 20%, or about $0.20 per 1,000 gallons of water sold, would be achieved. While the report has identified these potential capital cost reductions, our capital cost analysis is based on financing the full $547.5 million as identified in Table 6.1.

It should also be noted, most of the time cost savings are thought of as a reduction of costs to the end user. When comparing the plan outlined in this report against other long-term plan options, a reduction of O&M should also be viewed as an ability to fund additional capital projects. Funding additional capital, including but not limited to, repairs, replacement, or additional growth, has proven to be the best way to flatten rates and keep them cost competitive over the long term.

Table 6.3 identifies the average cost needed to fund the proposed plan. This was broken down first based on the capital required and is identified with the “Capital” fee. Each of the capital costs required were broken down by anticipated funding years and financed at SRF terms identified based on the “most likely” implementation plan. Without adjusting for inflation, the regional capital fee is $0.88 per 1,000 gallons sold.

The planning group recommended our analysis match the inflation assumptions outlined in the DMWW Long Range Plan. Capital cost inflation of 3.5% per year was used and O&M inflation of 2.3% was used. Table 6.3 also shows capital costs adjusted for inflation. Adjusting for inflation, capital costs rose to $1.82 per 1,000 gallons sold with O&M costs of $3.72 per thousand gallons.

6.5 AV E R AG E P R O D U C T I O N CO ST S

Based on water industry information and actual cost of production data gathered from similar utilities, McClure used an O&M cost of $1.50 per 1,000 gallons of water sold in our analysis. Note, this is not intended to be the full cost to the customer, but rather the cost for the regional group to produce and distribute bulk water to the region. Each community would have additional system O&M costs which will vary from community to community. This methodology is similar to other regional models and similar to that implemented by DMWW currently.

Our analysis indicates the actual O&M costs could be less than the $1.50 used based on the decisions of the final membership group. If all communities participate and maximize the economies of scale, it is estimated O&M costs could be reduced by up to 20%.

The reduction of O&M costs is significant in the long-term impact of the plan. This factor should not be taken lightly when determining whether to join the regional group long term. An O&M cost reduction of $0.25 per 1,000 gallons of water sold would create a $170 million savings for the region from 2020 to 2060. Theoretically, if $0.80 could be saved in O&M costs per 1,000 gallons over the next 40 years the cost of the entire capital fund requirement, $547.5 million, could be funded.


Projected Regional Capital Fund

Capital O&M Total Rate2020 2025 2030 2035 2040 2045 2050 2055 2060 Total $/1000 Gal $/1000 Gal $/1000 Gal

Adel 4.3 $21.60 $9.00 $9.50 $40.10 $0.93 $1.50 $2.43Clive 2.9 $0.00 $0.00 $1.50 $1.50De Soto 1.4 $8.40 $4.00 $6.60 $8.40 $27.40 $1.95 $1.50 $3.45Grimes 8.4 $25.80 $8.00 $5.00 $6.00 $41.50 $5.00 $91.30 $1.08 $1.50 $2.58Johnston 5.2 $4.00 $4.00 $0.08 $1.50 $1.58Urbandale 8.6 $6.00 $39.30 $27.00 $27.00 $99.30 $1.15 $1.50 $2.65Van Meter 1.8 $12.60 $14.80 $27.40 $1.52 $1.50 $3.02Waukee 10.9 $23.60 $32.75 $21.00 $15.00 $17.40 $36.00 $12.00 $157.75 $1.44 $1.50 $2.94WDM WW 18.6 $6.00 $41.25 $15.00 $27.00 $11.00 $100.25 $0.54 $1.50 $2.04Total 62.1 $53.40 $23.60 $112.00 $55.00 $69.40 $107.70 $55.40 $44.00 $27.00 $547.50 $0.88 $1.50 $2.38

Capital O&M Total Rate2020 2025 2030 2035 2040 2045 2050 2055 2060 Total $/1000 Gal $/1000 Gal $/1000 Gal

Adel 4.3 $21.60 $12.70 $22.45 $56.75 $1.31 $3.72 $5.04Clive 2.9 $0.00 $0.00 $3.72 $3.72De Soto 1.4 $11.85 $6.70 $13.13 $23.58 $55.26 $3.93 $3.72 $7.65Grimes 8.4 $25.80 $11.28 $8.38 $11.94 $98.07 $16.67 $172.14 $2.04 $3.72 $5.77Johnston 5.2 $6.70 $6.70 $0.13 $3.72 $3.85Urbandale 8.6 $10.05 $92.88 $90.01 $106.90 $299.83 $3.47 $3.72 $7.20Van Meter 1.8 $17.77 $29.45 $47.22 $2.61 $3.72 $6.34Waukee 10.9 $28.03 $46.20 $35.18 $29.85 $41.12 $101.04 $40.00 $321.42 $2.94 $3.72 $6.66WDM WW 18.6 $6.00 $58.19 $25.13 $53.72 $30.87 $173.92 $0.93 $3.72 $4.66Total 62.1 $53.40 $28.03 $157.99 $92.14 $138.09 $254.52 $155.50 $146.68 $106.90 $1,133.25 $1.82 $3.72 $5.54

Without Inflation

With Inflation

Table 6.3Projected Regional Capital Fund


6.6 R E G I O N A L I Z I N G VS I N D I V I D U A L SYST E M S

As shown in Table 6.3 the combined rate (Capital plus O&M) is estimated to be $2.38 per 1,000 gallons. Generally, communities are funding an existing O&M rate at or in excess of $1.50 per 1,000 gallons, which is already included in the existing rate structure of each community. Existing O&M rates for each community is predominately due to economies of scale, with systems operating smaller facilities having higher O&M rates. The ability of each utility to take advantage of the lower O&M costs are well documented. Focus should then be on the additional capital cost associated with providing the region enough water to take advantage of these economies of scale. The focus of this report is on the proposed capital costs in addition to the existing costs that are already built into existing rates.

Figure 6.2 identifies water utility rate costs for a 5,000 gallon per month water customer based on current (2020) metro area water rates. The six participating communities have monthly water bills ranging from $29.67 on the low end to $65.75 on the high end. It should be noted, Van Meter has implemented water rate increases in anticipation of future capital improvements. This does not reflect the current costs of providing water to the community.

Figure 6.3 reflects the impact of each community funding capital improvements individually and not as a regional group. When building improvements as individual communities, smaller communities such as Van Meter lose the benefit of economies of scale and could see rate increases as high as $58.00 per 1,000 gallons. In this analysis, only WDMWW would have a customer rate increase less than the anticipated $5.00 per 1,000 gallon.

Based on all communities participating in a regional utility, Figure 6.4 reflects the impact of implementing the capital fund fee via a $1.00 per 1,000 gallon rate increase to existing rates. Additional O&M was not added to the existing rates because current O&M charges built in the current rates are in excess of the anticipated regional O&M cost of $1.50 per 1,000 gallons produced. For some communities, the anticipated $1.50 per thousand gallon O&M rate would represent a significant reduction in O&M costs and savings to the local community. It can be clearly seen that participating in a regional utility is more cost effective to the customer base than for individual communities to fund improvements alone.

Additionally, Figure 6.5 reflects the borrowing power of a regional system when customer base and customer growth are factored over time. Today, the nine communities have an ability to finance $123.8 million of capital projects with implementation of a $1.00 per 1,000 gallons sold capital fee. This assumes DWSRF loan terms of 2% interest, a 20-year repayment and a 10% coverage ratio. As the regions population and customer base grows, additional funds of $48.0 million would be collected in the first 20 years. During the second 20-year timeframe, an additional $195.1 million of capital projects could be financed and an additional $82.1 million would be generated from additional customer growth. If a third round of project financing would be necessary, an additional $307.4 million of capital projects could be funded. This analysis was completed to reflect the potential buying power of the region and not to suggest the preferred method of capital financing. It is more likely that each project will be funded based on timing of project need. A fiscal consultant would be utilized to develop a utility budget and capital project financing plan.


Figure 6.2Average Customer Water Bill – 5,000 gallons/month

Current Water Bill


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All Go Alone (Cost per Thousand Gallons)

Figure 6.3Average Customer Water Bill

All Go Alone


Figure 6.4Average Customer Water Bill

All Communities Stay Together


Task 6 Meeting10/15/2019

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$48.0M (cash)

$82.1M (cash)

$756.4M in Total Funded Capital

$123.8M $195.1M $307.4M

Figure 6.5Potential Project Capitalization


7.0 S U M M A R Y OF F I N D I N G SThere is a growing need for additional water supply in the western Des Moines metro. DMWW and several Des Moines Metropolitan area communities have met over the past several years to explore the possibility of creating a regional drinking water governance structure, much like the current WRA structure of the sanitary sewer system. Several of the suburban communities feel they have no representation or say in how DMWW allocates costs, makes capital investments, and manages drinking water policy decisions. These communities rely on DMWW for some or all of their drinking water, and they would like a “seat at the table” and a voice in the decision making. If the metro communities cannot reach an agreement with DMWW and provide their customers an ability to have an impact in these decisions, they feel forced to look at options where they have more control over the future of their water supply and costs.

This report provides a framework where multiple western Des Moines suburban communities can work together to provide safe and reliable drinking water. This report has outlined the following:

1. There is an adequate supply of water and it is physically possible to regionalize the western Des Moines metro system independent of the rest of Des Moines and its suburban communities.

2. It is cost effective and financially feasible for the western communities to regionalize their water systems.3. There are economies of scale and cost savings in working together. The more communities stay together

and make decisions mutually beneficial to the region, the more potential there is to reduce the overall costs.

4. There is 93.0 MGD of water capacity available in the western region not including DMWW. This is enough water to serve the six (6) participating communities or a customer base of nearly 400,000 people, while allowing for nearly 3% population growth per annum in the region. This satisfies the demand for the entire planning area through the year 2050.

5. DMWW provides 35.35 MGD of purchase capacity to the planning area communities today. Depending on the per capita peak day water demands and which communities participate, DMWW purchase capacity may or may not be required to serve the planning area through 2060.

6. There remains an opportunity for DMWW and the western metro communities, that participated in the study, to have more dialogue.

Currently Adel and Grimes are under construction of their own water supply and treatment facilities that will provide 4.2 MGD of additional capacity. Their current water demands require this capacity growth and this study included their respective projects and costs in the overall plan. Urbandale Water Utility has competed a study to expand treatment capacity by 20.0 MGD. Van Meter, Waukee and West Des Moines Water Works are in the final planning stages of their own joint treatment facility, this would add an additional 21.0 MGD to the region over time. Each of these projects are included in our analysis. These should continue to be explored as the collective analysis is completed and each of the options are finalized.

This study was not intended to stop or slow any community from implementing water system improvements. Our analysis concludes it is both physically and economically feasible to develop the water supply and distribution system to create a western regional water system. The cost to supply, treat and distribute the bulk water in the region is estimated at $2.00 - $2.50 per 1,000 gallons of water.


The cost of this plan should be weighed by each member community against other proposed plans. We recommend looking at the benefits on a long-term horizon (20-40 years) as well as the long-term benefits of investing in capital improvements over the 40 plus year useful life of those improvements. Operational cost structures should not be minimized as they have a significant impact on rates over time. Where rate differentials are realized, these efficiencies should be considered to fund additional capital improvements. Under a regionalized plan, the anticipated cost of new infrastructure can be funded with a rate increase of $1.00 per 1,000 gallons of water sold.

Should the stakeholders wish to explore forming a regional water system, the next step would be to continue technical and governance discussions on how to best structure the regionalized system.

FINAL REPORT WEST METRO REGIONAL WATER FEASIBILITY STUDY

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