20200817Falls Water to Staff 33 Attachment 1a.pdf

Drinking Water Capital
Facilities Plan

S&A Project No. 18030

Final

September 2019

FALLS WATER COMPANY
DRINKING WATER
CAPITAL FACILITIES PLAN
Submitted to:
Falls Water Company
2180 N Deborah Dr
Idaho Falls, ID 83401

September 2019

7103 SOUTH 45TH WEST | IDAHO FALLS, ID 83402 | 208-522-1244

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18030 Falls Water Company Facility Planning Study i
EXECUTIVE SUMMARY
This document provides a review of the Falls Water Company (FWC) water supply and
distribution systems. The document details the existing conditions, identifies current needs,
projects future conditions, and provides detailed recommendations for improvements. Based on
the plan established in this report, Falls Water Company will be prepared to operate their system
efficiently and with a high level of service for the next 20 years and beyond.

Falls Water Company is unique in that it is located primarily in unincorporated areas of
Bonneville County. However, due to the presence of local water and sewer providers, building
densities are higher than typically found in County areas and are more similar to those in nearby
cities. Falls Water Company is located primarily south of U.S. Highway 26 in the area between
the Cities of Idaho Falls, Iona, and Ammon.

System performance was evaluated based on minimum service standards outlined by Idaho
DEQ. Basic deficiencies identified within the system include a lack of source redundancy
resulting in low system pressures during certain demand scenarios, inadequate fire flow to
several locations, and insufficient transmission capacity in a handful of pipelines. Additionally,
the remainder of FWC’s aging asbestos-cement pipes were identified for replacement.

A water model was prepared that demonstrated the system improvements needed to address
these issues. Most of the improvement recommendations are straightforward with optimal
solutions that are easily identifiable. Projects addressing fire flow capacity, transmission
capacity, and asbestos-cement pipe replacement all fall into this category. Regarding source
capacity, two primary alternatives were identified. The first alternative is to increase peak hour
source capacity through a combination of adding new wells and the construction of a storage
tank and booster pump station. The second alternative is to increase peak hour capacity strictly
through the construction of additional wells.

The second alternative of increasing peak hour capacity by adding new wells was ultimately
found to be the least costly alternative. Nonetheless, Alternative 1 with the construction of a new
storage tank has several advantages. A tank and booster station would improve source reliability.
Booster pumps can be constructed allowing for redundancy so that full capacity can be
maintained even in the event of a pump failure. Meeting peak flows using equalization storage
would also reduce the water right diversion rate that Falls Water Company would need to
purchase. A tank would also reduce sand in the system as any sand produced by the wells would
settle in the tank. Based on these advantages, Falls Water Company should consider constructing
a storage tank, even though the overall cost is higher.

It is also recommended that Falls Water Company actively plan for water right acquisitions. Due
to the time associated with procuring water rights, FWC should always have a minimum reserve
of three years of water right capacity. Under present conditions, adding 535 acre-feet of volume
and 3,170 gpm of diversion rate to their existing water right capacity is recommended.

Drinking water quality and energy use within the system were also investigated. Water quality
was found to be very good. Water age within the system is very low due to the system’s lack of

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18030 Falls Water Company Facility Planning Study ii
storage. As a result, the modeled chlorine residuals were also very good. Wells #1 and #5 were
found to be the least expensive sources to operate based on energy intensity. Wells #2, #4, #6,
and #7 also had relatively low energy use. Conversely, Wells #8, #9, and #10 had the highest
energy intensities of the FWC sources. Falls Water Company can reduce energy consumption
and by extension pumping costs by preferentially utilizing sources with lower energy intensities.

Falls Water Company should also investigate more stable ways to operate their system during
high demand periods. Modeling suggested, and conversations with FWC staff confirmed, that the
current automated SCADA-controlled operation of the system is prone to instability. For
example, pumps have been observed frequently cycling on and off with pressures jumping up
and down due to the changing pump status. The current framework of rules governing system
operation is based on pressure control settings. A hybrid approach of using the pumps with
variable frequency drives (VFDs) to maintain pressure and auxiliary pumps set to come on based
on the flow of the VFD pumps was explored and found to be more stable and reduce diurnal
pressure change within the system.

Table 14, Table 15, and Table 16 present a list of the projects and costs identified by this report.
A map showing all capital improvements is given as Figure 9.

Table 14 – Existing Project Costs with Alternative 1
ID Project Description Estimated Cost
A-1 Ryan Anderson Development Well $771,700
A-2 Crowley Road from 1st Street to John Adams Pkwy (8" Extension) $319,000
A-3 Lincoln Road from 4743 E to Wood River Road (12" Extension) $70,500
A-4 Replace 6" Pipe in Fall River Road with 8" Pipe $72,900
A-5 Replace 6" Pipe in Edwards Drive with 8" Pipe $183,300
A-6 Harding Lane from Kit Lane to 1st Street (8" Extension) $95,900
A-7 25th East and Iona Road Waterline Extensions $1,233,800
A-8 Ammon Road from Pearce Drive to Greenwillow Drive (12" Extension) $147,800
A-9 Ammon Road from Greenwillow Drive to O'Bryant Street (10" Extension) $187,200
A-10 Replace 6" Pipe in Dixie Street with 10" Pipe $42,600
A-11 Replace 8" Pipe East of Well 2 with 12" Pipe $37,400
A-12 First Street from Robison Drive to Wheatfield Lane (10" Extension) $245,100
A-13 First Street from Ammon Road to Nassau Drive (10" Extension) $278,800
A-14 Fallsbrook asbestos cement pipes - Lakewood Street and Upland Street $411,900
A-15 Fallsbrook asbestos cement pipes - Jensen Drive $141,900
A-16 Fallsbrook asbestos cement pipes - Contor Avenue $454,800
A-17 Fallsbrook asbestos cement pipes - Crawford Street $131,100
A-18 Fallsbrook asbestos cement pipes - North Adams Drive $166,500
A-19 Fallsbrook asbestos cement pipes - Mobile Drive $67,400
A-20 Increase the volumetric water right capacity by at least 535 acre-feet and the
diversion rate by 3,170 gpm $1,230,500
A-21 Reconfigure the SCADA system control of pump start and stop triggers $34,500
B-1 New 2.0 MG Storage Tank $2,517,200
B-2 New Booster Pump Station with 5,500 gpm capacity $426,700
B-3 New Tank Pipeline Upgrades $367,800
TOTAL $9,636,300

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18030 Falls Water Company Facility Planning Study iii
Table 15 – Existing Project Costs with Alternative 2
ID Project Description Estimated Cost
A-1 Ryan Anderson Development Well $771,700
A-2 Crowley Road from 1st Street to John Adams Pkwy (8" Extension) $319,000
A-3 Lincoln Road from 4743 E to Wood River Road (12" Extension) $70,500
A-4 Replace 6" Pipe in Fall River Road with 8" Pipe $72,900
A-5 Replace 6" Pipe in Edwards Drive with 8" Pipe $183,300
A-6 Harding Lane from Kit Lane to 1st Street (8" Extension) $95,900
A-7 25th East and Iona Road Waterline Extensions $1,233,800
A-8 Ammon Road from Pearce Drive to Greenwillow Drive (12" Extension) $147,800
A-9 Ammon Road from Greenwillow Drive to O'Bryant Street (10"
Extension) $187,200
A-10 Replace 6" Pipe in Dixie Street with 10" Pipe $42,600
A-11 Replace 8" Pipe East of Well 2 with 12" Pipe $37,400
A-12 First Street from Robison Drive to Wheatfield Lane (10" Extension) $245,100
A-13 First Street from Ammon Road to Nassau Drive (10" Extension) $278,800
A-14 Fallsbrook asbestos cement pipes - Lakewood Street and Upland Street $411,900
A-15 Fallsbrook asbestos cement pipes - Jensen Drive $141,900
A-16 Fallsbrook asbestos cement pipes - Contor Avenue $454,800
A-17 Fallsbrook asbestos cement pipes - Crawford Street $131,100
A-18 Fallsbrook asbestos cement pipes - North Adams Drive $166,500
A-19 Fallsbrook asbestos cement pipes - Mobile Drive $67,400
A-20 Increase the volumetric water right capacity by at least 535 acre-feet and
the diversion rate by 3,170 gpm $1,230,500
A-21 Reconfigure the SCADA system control of pump start and stop triggers $34,500
C-1 New Well in Northeast Area of System $674,100
TOTAL $7,096,300

Table 16 – 20-Year Future Project Costs
ID Project Description Estimated Cost
D-1 New Wells with about 9,000 gpm Capacity $4,629,900
D-2 New 1.0 MG Storage Tank $1,280,000
D-3 New Booster Pump Station with 3,000 gpm capacity $365,700
D-4 Crowley Road from Green Willow Lane to John Adams Pkwy (12"
Extension) $424,800
D-5 Iona Road from Pinnacle Drive to 3452 Iona Road (12" Extension) $392,200
D-6 Replace 6" Pipe in Monte Vista Avenue with 12" Pipe $262,900
D-7 Increase the volumetric water right capacity by 3,600 acre-feet and the
diversion rate by 9,100 gpm $8,280,000
TOTAL $15,635,500

FALLS WATER COMPANY
RECOMMENDED PROJECTS
FIGURE 9
Existing Wells
Future Tanks
Future Booster Pump Stations
Existing FWC Pipes
2-inch
4-inch
6-inch
8-inch
10-inch
12-inch
Pipeline Projects
8-inch
10-inch
12-inch
16-inch
20-inch
Developer Pipeline Projects
10-inch
12-inch
Legend
U.S. Hwy 26
N
25th East
B-1, B-2, & B-3
Ammon Rd
1st St
15th East
A-13
ID Hwy 43
Crowley Rd
D-2 & D-3
Lincoln Rd
A-14 to A-19
Iona Rd
49th North

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TABLE OF CONTENTS
EXECUTIVE SUMMARY .................................................................................................................... i
LIST OF TABLES ............................................................................................................................ vii
LIST OF FIGURES ......................................................................................................................... viii
LIST OF ABBREVIATIONS ............................................................................................................... ix
1.0 INTRODUCTION .................................................................................................................... 1
1.1 Purpose ............................................................................................................................. 1
1.2 Report Organization ......................................................................................................... 1
1.3 Acknowledgement ............................................................................................................ 1
2.0 EXISTING CONDITIONS ........................................................................................................ 2
2.1 Boundaries ........................................................................................................................ 2
2.2 Existing Environmental Conditions of the Planning Area ............................................... 2
2.3 Description of Existing Water System ............................................................................. 6
2.4 Violations of Safe Drinking Water Act and Rules for Public Drinking Water Systems 19
2.5 Sanitary Survey .............................................................................................................. 19
2.6 Existing Deficiencies...................................................................................................... 19
3.0 FUTURE CONDITIONS ........................................................................................................ 21
3.1 Future Growth ................................................................................................................ 21
3.2 Forecast of Demand ....................................................................................................... 23
3.3 User Charges and Operations and Maintenance Budget ................................................ 24
3.4 Hydraulic Model Analysis ............................................................................................. 24
3.5 Drinking Water Improvements needed for a Minimum 20-year period ........................ 25
4.0 DEVELOPMENT AND INITIAL SCREENING OF ALTERNATIVES ......................................... 30
4.1 Problems/Deficiencies with the Existing Water System ................................................ 30
4.2 Development of Alternatives ......................................................................................... 31
4.3 Discussion of Treatment Requirements for New or Upgraded Facilities ...................... 34
4.4 Storage, Pumping and Pressure Requirements ............................................................... 34
4.5 Separate Irrigation Facilities .......................................................................................... 35
4.6 Staged Distribution ......................................................................................................... 35
4.7 Environmental Impacts Associated with all Alternatives .............................................. 35
4.8 System Classification and Operator Licensure .............................................................. 35
5.0 FINAL SCREENING OF PRINCIPAL ALTERNATIVES ........................................................... 36
5.1 Evaluation of Costs ........................................................................................................ 36
5.2 Consideration of any Impacts to Water Supply Systems ............................................... 38
5.3 Comparison of Alternatives by Providing a Broad-Brush Environmental Analysis ..... 38
6.0 SELECTED ALTERNATIVE AND IMPLEMENTATION........................................................... 39
6.1 Justification and Detailed Description of Recommended Alternative ........................... 39
6.2 Preliminary Design of Recommended Alternative ........................................................ 39
6.3 Justification of Recommended Alternative .................................................................... 40
6.4 Total Project Cost Estimate ............................................................................................ 40
6.5 Owner’s Capability to Finance and Manage Projects .................................................... 40
6.6 Availability of the Most Suitable Land .......................................................................... 41
REFERENCES ................................................................................................................................. 42
7.0 APPENDICES ....................................................................................................................... 43
Appendix A: Relevant Engineering Data .............................................................................. A-1
Appendix B: DEQ Sanitary Survey ....................................................................................... B-1

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18030 Falls Water Company Facility Planning Study vi
Appendix C: Water Right Reserve Capacity Memo .............................................................. C-1
Appendix D: Water Quality Data .......................................................................................... D-1
Appendix E: Calibration Data ................................................................................................. E-1
Appendix F: Required Fire Flows from Idaho Surveying & Rating Bureau .......................... F-1
Appendix G: Electronic Files ................................................................................................. G-1
Appendix H: Cross Connection Control Plan Information .................................................... H-1
Appendix I: Falls Water Company Revenue and Expense Detail ........................................... I-1
Appendix J: Drinking Water System Classification Worksheet ............................................. J-1

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LIST OF TABLES

Table 14 – Existing Project Costs with Alternative 1 ..................................................................... ii
Table 15 – Existing Project Costs with Alternative 2 .................................................................... iii
Table 16 – 20-Year Future Projects Costs ..................................................................................... iii
Table 1 – Summary of Sources ....................................................................................................... 8
Table 2 – Energy Use of FWC Sources ........................................................................................ 14
Table 3 – FWC Well Settings ....................................................................................................... 18
Table 4 – Existing Deficiencies .................................................................................................... 19
Table 5 – Historical Growth of Falls Water Company and Bonneville County ........................... 21
Table 6 – Projected Future Demands ............................................................................................ 24
Table 7 – Projects Addressing Existing Deficiencies ................................................................... 25
Table 8 – Alternative 1 with Storage Tank ................................................................................... 26
Table 9 – Alternative 2 with Additional Well and No Storage Tank ........................................... 26
Table 10 – Projects Addressing Future Deficiencies .................................................................... 27
Table 11 – Developer Driven Transmission Pipeline Lengths ..................................................... 28
Table 12 – Budgetary Cost Estimates for Existing Projects with Limited Alternatives ............... 32
Table 13 – Alternative 1 Capital Cost Summary .......................................................................... 33
Table 14 - Existing Project Costs with Alternative 1 ................................................................... 36
Table 15 - Existing Project Costs with Alternative 2 ................................................................... 37
Table 16 – 20-Year Future Projects Costs .................................................................................... 37

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LIST OF FIGURES

Figure 9 – Recommended Project Map ......................................................................................... iv
Figure 1 – Vicinity Map .................................................................................................................. 3
Figure 2 – Planning Area ................................................................................................................ 4
Figure 3 – Existing Distribution System ......................................................................................... 7
Figure 4 – Maximum Day Diurnal Demand ................................................................................. 10
Figure 5 – Pipe Length vs. Diameter ............................................................................................ 12
Figure 6 – Water Age Modeling Results ...................................................................................... 15
Figure 7 – Chlorine Modeling Results .......................................................................................... 16
Figure 8 – Surrounding Growth Boundaries ................................................................................. 22
Figure 9 – Recommended Project Map ........................................................................................ 29

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LIST OF ABBREVIATIONS

AF Acre-feet
Alt. Alternative
AMSL Above Mean Sea Level
bgs Below Ground Surface
cfs Cubic Feet per Second
DEQ Department of Environmental Quality
EDU Equivalent Dwelling Unit
EID Environmental Information Document
EPA Environmental Protection Agency
F Fahrenheit
fps feet per second
FWC Falls Water Company
gpd Gallons per day
gpm Gallons per minute
Hp Horse power
HGL Hydraulic Grade Line
IPUC Idaho Public Utilities Commission
kW Kilowatt
mg/L Milligrams per liter (equivalent to parts per million)
Mo Month
O&M Operations and Maintenance
ppm Parts per million (equivalent to mg/L)
psi Pounds per square inch
PVC Poly Vinyl Chloride
Rules Idaho Drinking Water Rules (IDAPA 58.01.08)
S&A Schiess and Associates, PC
TDH Total Dynamic Head
VFD Variable Frequency Drive

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1.0 INTRODUCTION
This study provides analysis of the Falls Water Company (FWC) drinking water distribution
system. The condition of the existing system is reviewed, and deficiencies are identified along
with recommendations to address those deficiencies. The future conditions of the system were
forecast over a 20-year planning interval using population and land use projections. Based on that
forecast, the future system was analyzed, and recommendations are provided in order to prepare
for the expected growth. This study represents a thorough investigative process and will provide a
framework that enables Falls Water Company to make informed management decisions.
1.1 Purpose
The purpose of this facilities planning document described in more detail is to investigate,
evaluate, and document the condition of the Falls Water Company’s, water supply and
distribution capabilities, identify problems and needs, develop alternative solutions to correct
deficiencies, and encourage FWC to select preferred alternatives in order to bring the
system’s water supply and distribution systems into compliance with current and expected
regulations for a 20 year planning period.

This study also addresses the ability of the water system to meet the current requirements for
public drinking water systems in Idaho, which regulate system pressures and capacity to meet
peak demands and fire flow requirements.
1.2 Report Organization
The organization follows the DEQ facility plan format for drinking water facility planning
studies.
1.3 Acknowledgement
We thank Falls Water Company for the opportunity to provide this study and for their help
and participation in the discovery process. We specifically appreciated the cooperation and
assistance of Scott Bruce, the General Manager, and Tony Wise, the Operations Manager. We
also thank DEQ for their input and suggestions during the study process.

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2.0 EXISTING CONDITIONS
Falls Water Company (PWS# ID7100030) is a privately-owned water utility serving customers in
portions of Bonneville County east of Idaho Falls and north of Ammon. As a privately-owned for-
profit utility, FWC is regulated by the Idaho Public Utilities Commission. Nearly all of Falls Water
Company’s service area is in unincorporated areas of the County; however, FWC does serve a
small portion of Ammon. Figure 1 shows the location of Falls Water Company in relation to the
surrounding communities.
2.1 Boundaries
The planning area for this study was identified based on discussions with FWC personnel and
growth estimates. It includes all areas currently served by FWC and areas that are projected to
be served within the 20-year planning horizon. Figure 2 shows the extents of the planning area.

2.2 Existing Environmental Conditions of the Planning Area
Physiography, Topography, Geology and Soils
Falls Water Company is in the Eastern Snake River Plain. The general slope of the land is
from northeast to southwest. The highest elevation within the current service area is about
4,793 feet AMSL while the lowest is about 4,725 feet AMSL.

Primary east-west arteries include 1st Street, Lincoln Road, and Iona Road. North-south
arteries include 25th East, Ammon Road, and Crowley Road. In addition, two rail lines
converge to form a “T” within the FWC service area. (see Figure 1). Development is
progressing rapidly. However, the occasional open field can still be found within the
interior of the system and is common about the periphery.

Soils in and around FWC are classified as primarily Paesl silty clay loam or Paul silty clay
loam by the U.S. Department of Agriculture Soil Conservation Survey. Both are deep well
drained soils. Paesl silty clay loam is characterized by an upper layer of silty clay loam
about 25 inches thick overlaying a layer of very gravelly loamy coarse sand between 25
and 60 inches below ground. Paul silty clay loam is characterized by an upper layer of silty
clay loam about 45 inches thick overlaying a layer of silt loam between 45 and 60 inches
below ground. Additionally, the Polatis-Rock outcrop complex is found along the southeast
side of the service area. Within the rock outcrop, bedrock exists at depths of 20 to 40 inches.
Surface and Ground Water Hydrology
The south fork of the Snake River provides the main source of groundwater through
various irrigation canals that replenish the aquifer. Replenishment also comes from the
canals fed by Willow Creek. Surface canals and creeks in the area include Ammon
Lateral, Center Canal, Crow Creek, East Center, Payne Lateral, Sand Creek, and West
Center Canal.

The entire study area is over a very porous aquifer known as the Eastern Snake River
Plain Aquifer. This aquifer has been designated as a sole source aquifer by the EPA in
that it supplies almost all the water in the area for drinking and is the only source of
drinking water. Evaluation of the source water assessments performed by DEQ on all
FALLS WATER COMPANY VICINITY MAP
FIGURE 1
Falls Water Company
Existing Service Area
Ammon
Idaho Falls
Iona
IBSD Service Area
IBSD-IF Agreement Boundary
Railway
Legend
N
U.S. Hwy 26
25th East
Ammon Rd
1st St
15th East
Crowley Rd
Lincoln Rd
Iona Rd
49th North
ID Hwy 43
FALLS WATER COMPANY
20-YEAR PLANNING AREA
FIGURE 2
Falls Water Company
20-Year Planning Area
20-Year Growth Areas
Ammon
Idaho Falls
Iona
Legend
U.S. Hwy 26
N
25th East
Ammon Rd
1st St
15th East
Crowley Rd
Lincoln Rd
Iona Rd
49th North
ID Hwy 43

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18030 Falls Water Company Facility Planning Study 5

public water systems in the area since 1996 validates the fact that the majority of the
water for the study area derives from a single source, the Snake River near Ririe, Idaho,
northeast of the study area. The delineated impact zones for most of the wells in the study
area overlap and converge as they run northeast from the well sources.

Because of the potential for groundwater contamination from various potential
contamination sources, projects proposed in this study will be subject to an EPA
environmental assessment if the entities seek federal financial assistance.
Utility Use and Energy Production
The entire area of the study is served by Rocky Mountain Power for electrical power.
Most areas are serviced by Intermountain Gas, but some outlying areas may receive gas
service by local propane gas suppliers. In addition to Falls Water Company, several small
private community water systems exist within the study area along with private wells
serving individual residences.

Sewer service is mainly provided by Iona-Bonneville Sewer District (IBSD) with some
private septic systems interspersed.
Floodplains and Wetlands
With Sand Creek cutting through the study area from north to south, substantial portions
of the study area fall within the 500-year flood plain as designated by the Federal
Emergency Management Agency (FEMA). A small portion west of Crowley Road in the
extreme southeast corner of the study area falls within the 100-year flood plain. These
maps were not included in the appendices due to their size.

Very little wetlands exist in the study area other than streams and canals in some isolated
areas as most of the ground has been urbanized or is cultivated for farm use.
Public Health Considerations
The combined study area encompasses about 8.2 square miles east of Idaho Falls in
Bonneville County. All persons residing in this area drink the same water as it all derives
from a sole source aquifer, the Eastern Snake River Plain Aquifer. As such the threat to
the well-being of the large populace cannot be overstated. Contamination of the aquifer
northeast of Ucon or in any area to the east included in the delineated zones of
contribution has the potential to contaminate the water for thousands of residents. Every
system and individual in the study area should have an interest in protection of their own
system or source and the protection of all sources within the study boundaries.
Proximity to Sole Source Aquifer
The entire study area sits on top of the Eastern Snake River Plain Aquifer. Protection
from groundwater contamination by surface water or other potential contamination
sources is essential. Development and expansion of systems must take this into
consideration in the planning phases.
Precipitation, Temperature and Prevailing Winds
The study area is located on the Snake River Plain. The Rocky Mountains partially shield
the area from cold Artic winds and winters are generally cold but not severe. In the
summer, days are hot, but nights are generally cool. Average daily temperatures in the
summer are in the 60’s and in the winter the average daily temperature drops into the 20’s

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to low 30’s. The extreme high in the summer approaches 100 and the extreme low in the
winter approaches -30oF. Yearly precipitation averages are about nine inches of total
precipitation and 32 inches of snowfall average for the entire Bonneville County area.
The growing season defined by days above 32oF, varies from 90 days to 140 days and the
average year will be about 110 to 120 days.
Air Quality and Noise
The communities served by Falls Water Company are relatively quiet. Most of the land is
used for residential uses, though commercial and industrial use is growing. In addition,
farming is still a dominant industry in the surrounding rural areas. The largest
contributors to air pollution are expected to be traffic and airborne dust resulting from
farming operations and wind. Traffic, particularly heavy equipment and trucks, is
expected to be the largest contributor of noise.
Socioeconomic Profile
Housing within the Falls Water Company Service area is mostly single-family residences.
The median value of owner-occupied units was 161,000 in 2017. Additionally, there is a
manufactured home park in the southern portion of the system, and a few multi-family
residences have been added within recent years. The average age of a resident in Bonneville
County is 32.6 years. The median income is $54,150 with a reported poverty rate of 10.5%.
2.3 Description of Existing Water System
A map of the existing FWC distribution system is included as Figure 3. At the end of 2018,
Falls Water Company served 5,260 connections. Of that total, 5,001 are residential
connections while 259 connections are nonresidential. All connections served by Falls Water
Company are metered. An Equivalent Domestic Unit (EDU) is a measure used in comparing
water demand from non-residential connections to residential connections. The number of
EDUs served by the FWC drinking water system was calculated by dividing the total annual
residential demand by the total number of residential connections. Using the billing data
provided by FWC, the annual volume of water used by residential customers was 3,547 AF.
Converting the annual volume to an average flow and dividing by the number of residential
connections gives an average demand of 0.440 gpm/EDU (634 gpd/EDU). In order to express
non-residential demands in terms of EDUs, each non-residential demand was divided by the
average demand per residential connection. The total number of existing EDUs computed for
the FWC system was 5,370. The raw data associated with the EDU calculations are included
in Appendix A.
Sources
Falls Water Company receives water from nine sources as summarized in Table 1. In all,
the total capacity of Falls Water Company’s sources is about 10,500 gpm. Within the
following paragraphs each well is discussed in detail. For pictures of each facility, we
refer you to the DEQ Sanitary Survey in Appendix B. Additional documentation for the
FWC wells (pump curves, well logs, pump test data, etc.) can be found in Appendix A.

Well #1
Well #1 is located along Ammon Road in Fallsbrook mobile home court. The well pump
is a vertical turbine type with a 75 Hp motor and is driven by a variable frequency drive
(VFD). The well was originally drilled in 1955 and subsequently redrilled in 1976. It
was constructed with 12-inch casing and is 215 feet deep. When the well was redrilled,
FALLS WATER COMPANY
EXISTING SYSTEM
FIGURE 3
Existing FWC Wells
FWC Pipes
2-inch
4-inch
6-inch
8-inch
10-inch
12-inch
Legend
N
U.S. Hwy 26
25th East
Ammon Rd
1st St
15th East
Crowley Rd
Lincoln Rd
ID Hwy 43
Iona Rd
49th North

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Table 1 – Summary of Sources
Well Pump Capacity (gpm)
Well #1 800
Well #2 500
Well #4 1,500
Well #5 800
Well #61 750
Well #71 750
Well #8 1,500
Well #9 2,700
Well #10 1,200
Total 10,500
1. Wells 6 and 7 are treated as separate wells within this document; however, they are
individual submersible pumps installed within the same well borehole.

the static water level was recorded as 47 feet bgs. Well #1 was pump tested at 1,100 gpm
with a recorded drawdown of 63 feet. Under normal operating conditions, Well #1 has a
capacity of 800 gpm. However, as demands increase and system pressure drops, higher
flow rates can be reached. A limited review of SCADA data from July 2018 found flows
reaching 960 gpm during periods of high demand.

Well #2
Well #2 is located along North Eden Drive in Fallsbrook mobile home court. The well
was drilled in 1960 and was constructed with a 16-inch casing to a depth of 147 feet. The
depth to water was reported as 58 feet, and the well was test pumped at just over 2,900
gpm. Well #2 generally has a capacity of about 500 gpm; however, higher flow rates of
550 gpm have been observed during peak demands when system pressure is lower.

Well #4
Well #4 is located along North Eden Drive adjacent to Well #2. The well pump is a
vertical turbine type with a 150 Hp motor. Well #4 was drilled in 1974 and was
constructed to a depth of 142 feet with a 16-inch casing. The well was pump tested at a
flow of 1,800 gpm. The static water level was 42 feet bgs and the pumping level was 43
feet bgs during the test. The pumping water level at Well #4 was monitored over several
years between 1994 and 2002 and varied between 39 feet and 66 feet bgs. As of 2019,
Well #4 currently has a capacity of 1,500 gpm during normal operation.

Well #5
Well #5 is located along Ammon Road, just north of Deloy Drive and south of the
railroad tracks. The well was constructed in 1979 to a depth of 337 feet with a 20-inch
casing. At the time of construction, the water level was 92 feet bgs. Well #5 was pump
tested at 810 gpm and the drawdown was 62.5 feet. The pump at Well #5 is a vertical
turbine pump with a 75 Hp motor. The current normal capacity of Well 5 is about 800
gpm. Well #5 includes a manually started emergency backup generator.

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Well #6
Well #6 includes two submersible pumps installed within the same borehole. For
convenience through this report the two pumps will be referred to as Wells #6 and #7.
The well was drilled in 1989 to a depth of 150 feet and is located along North Eden Drive
just north of the site for Wells #2 and #4. A 20-inch casing was installed, and the first of
the two pumps was installed after the well was completed. The second pump was added
in 1998. At the time of construction, the static water level was 56.5 feet bgs. The highest
flow reached during the pump test was 2,650 gpm with a corresponding drawdown of 8.9
feet. The current normal capacity for each of the two pumps is about 750 gpm.

Well #8
Well #8 is a leased well that was originally constructed in 1955. It is located along
Lincoln Road at about 2877 East. Well #8 has a depth of 410 feet and was constructed
with a 20-inch casing. After construction, the well was pump tested. The peak flow
reported from the pump test was 2,400 gpm. The static water level was 122 feet and the
pumping level was about 156 feet. A vertical turbine pump driven by a 150 HP motor is
currently installed in the well and the capacity is 1,500 gpm.

Well #9
Well #9 is located along Ammon Road near Well #5 on the north side of Deborah Drive.
The well pump is a vertical turbine type with a 400 Hp motor and is driven by a variable
frequency drive (VFD). The well was constructed in 2008 with a 12-inch telescoping
screen and a total depth of 408 feet. The static water level was measured as 132 feet bgs.
Well #9 was pump tested at 3,000 gpm with a drawdown of 78 feet. Due to some sanding
at higher flows, production at Well #9 has been limited to 2,700 gpm. Well #9 includes
an emergency backup generator.

Well #10
Well #10 is FWC’s newest well, having been put in service in 2018. Well #10 has a
completed depth of 360 feet with an 18-inch casing and a 14-inch screen. It is located
along 49th North at about 3730 East. Well #10 was pump tested at 1,300 gpm with a
measured drawdown of 48 feet. A vertical turbine pump driven by a 150 HP motor was
installed and the capacity of Well #10 is 1,200 gpm. Upgrades of a VFD and a backup
generator are planned for Well #10 but have not yet been installed.

In general, FWC’s sources are operated with at least one of the VFD controlled pumps
operating (usually Well #9) using a pressure control setting. The VFD controlled pump
ramps up and down as demand in the system changes, in order to maintain a constant
pressure. As system demand increases and the VFD controlled pump is no longer able to
maintain pressure, additional wells are set to turn on via SCADA control. The situation is
reversed as demand decreases. In that case, pressure rises, and pumps are shut down.
During a normal summer day, flows are high throughout the night, and lower during the
day and the cycle of sources ramping up and ramping down will occur once a day.

IDAPA 58.01.08 Subsection 552.01.b.i mandates that public water systems “shall be
capable of providing sufficient water during maximum day demand conditions,
including fire flow where provided, to maintain a minimum pressure of twenty
(20) psi throughout the distribution system, at ground level, as measured at the service

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18030 Falls Water Company Facility Planning Study 10

connection or along the property line adjacent to the consumer’s premises.” Moreover,
Subsection 552.01.b.v further stipulates a minimum pressure of 40 psi during peak hour
demand conditions for: 1) Any public water system constructed or substantially modified
after July 1, 1985; 2) Any new service area; 3) Any public water system that is
undergoing material modification where it is feasible to meet the pressure requirements
as part of the material modification. In addition, the FWC prefers that the distribution
system maintain a minimum of 50 psi at all points in the system under peak hour
conditions to avoid customer complaints.

In order to evaluate system performance based on these minimum pressure criteria, it was
necessary to identify the maximum day flow, peak hour flow, and fire suppression flow.
The maximum day and peak hour flows were addressed by investigating SCADA data for
each of the system’s sources. Data from 2018 was reviewed, and the maximum day for
that year was identified as July 14th. Figure 4 is a plot of the demand data for July 14th,
2018.

Figure 4 – Maximum Day Diurnal Demand

Based on these data, the maximum day demand for FWC was found to be 7,200 gpm and
the peak instantaneous demand was 10,600 gpm. The general pattern of water use is high
demand during the evening, nighttime, and morning hours with lower demands during the
daytime. The effect of nighttime sprinkler irrigation is evident in the demand curve.
During the time between midnight and 6 AM, pulses occur every hour, as a by-product of
customers setting their sprinklers to turn on at the top of the hour. On a per EDU basis,
the maximum day demand is 1.34 gpm/EDU and the peak instantaneous demand is 1.97
gpm/EDU. Due to the high quality of the demand data, and because the observed peak
was relatively constant between 2:00 AM and 3:00 AM, the peak instantaneous demand
was substituted for the peak hour demand for all analyses of system performance.

0
2,000
4,000
6,000
8,000
10,000
12,000
0:00 2:00 4:00 6:00 8:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 0:00
Fl
o
w

(
g
p
m
)
Time (hh:mm)
Instantaneous Demand Maximum Day Demand

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The annual average demand was determined by reviewing annual production data and
was found to be 2,570 gpm. Seasonal demand variation was investigated by reviewing
monthly production data. Average use during the months of January, February, March,
and December was 806 gpm. Assuming no outdoor use occurred during those months,
and that indoor use remains relatively constant throughout the year, outdoor demand can
be computed by subtracting the indoor use from the total demand. For example, the
average day demand in 2018 was 2,570 gpm. Of that total, 806 gpm is related to indoor
use and 1,764 gpm is associated with outdoor use. Therefore, about 69% of the water
supplied by FWC was used to meet outdoor demands. Extending the comparison to
maximum day gives 6,394 gpm of outdoor use during maximum day demand. The
outsized contribution of outdoor watering to the total maximum day demand
demonstrates the importance of educating customers about correct sprinkler irrigation
practices.

The system’s ability to provide water during a power outage was also reviewed. Under
current conditions, Wells #5 and #9 include backup generators with only the Well #9
generator having automatic switch-over capability. The combined capacity for those two
sources is 3,500 gpm. During a power outage IDAPA 58.01.08 Subsection 501.07
specifies that minimum pressure requirements be met for the conditions of average day
demand plus fire flow. Bonneville County fire authorities require a minimum 1,500 gpm
fire suppression flow throughout the Falls Water Company system. Adding that to the
average day flow of 2,570 gives a required capacity of 4,070 gpm for sources with
backup power. As a result, FWC does not currently have adequate source capacity with
standby power. However, Falls Water Company is in the process of adding standby
power to Well #10, which would increase the total capacity of sources with standby
power to 4,700 gpm.
Water Rights
S&A recently prepared an analysis of FWC’s water right reserve capacity (see Appendix
C). In summary, the current annual volume associated with FWC’s water rights is 4,970
acre-feet. An additional 97.07 acre-feet is available through leased water rights. In terms
of instantaneous capacity, the allowable diversion rate of owned rights is 9,847 gpm with
an additional 2,769 gpm associated with leased rights. Due to the long-term uncertainty
associated with leased rights, it is recommended that they be disregarded with respect to
future planning. If only the owned rights are considered, FWC has an existing reserved
capacity of 1,071 EDUs with respect to annual volume, and a deficit of 382 EDUs with
respect to diversion rate. It is recommended that FWC should conservatively plan to
always have a minimum of three years of reserve capacity. Allowing for a three-year
span with higher than average growth as well as the possibility for an unusually hot, dry
summer, it is recommended that FWC add 535 acre-feet and 3,170 gpm to their existing
water right capacity.
Treatment Systems
Water from the following 6 sources is treated with chlorine: Well #2, Well #4, Well #5,
Well #8, Well # 9, and Well #10. Dosing is conducted in order to maintain a residual
chlorine concentration of about 0.1 mg/L at the tap. Water quality test results are included
in Appendix D. In addition, Wells #4, #5, and #10 are equipped with, sand separators in
order to prevent sand from entering the distribution system.

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Distribution System
The distribution system consists of approximately 79 miles of 4-inch, 6-inch, 8-inch, 10-
inch and 12-inch pipes. Figure 5 presents a summary of pipe length by diameter.

Figure 5 – Pipe Length vs. Diameter

Nearly all the pipe is PVC (mostly SDR 21 IPS and a minority amount of C900);
however, there is some asbestos-cement pipe on the west side of the Fallsbrook mobile
home court and a very limited amount of ductile iron pipe, mostly on the well sites.
Hydraulic Model Analysis of Existing System
A computer model of the FWC’s water distribution system was developed to analyze the
performance of the existing distribution system and to prepare solutions that address
deficiencies identified by the modeling. The software used for the model was EPANET
2.0. EPANET 2.0 is a computer program that models the hydraulic behavior of pipe
networks. In order to develop the model for this study S&A started with the model
prepared for FWC’s previous master plan in 2006. The model geometry was updated
using data provided by FWC.

Water demands were allocated in the model based on billing data from July 2018 through
the process of geocoding. Geocoding is the computational process of converting a street
address to a physical location on the Earth’s surface. After geocoding, each of the
demands was assigned to the model node closest to the geocoded location. The peak
monthly flows obtained from billing data were then scaled by maximum day production
data in order to convert the monthly flow into a maximum day demand flow. In this
manner, the model was prepared to model the maximum day demand with a flow of
7,200 gpm.

The water model was also converted into an extended period model. This was
accomplished by adding the diurnal curve shown in Figure 4 to describe how demand
changes throughout the day and by adding controls that govern how the system reacts to
changing demand conditions. Converting the model to an extended period simulation
0
5
10
15
20
25
30
35
40
4 6 8 10 12
Le
n
g
t
h

(
m
i
l
e
s
)
Pipe Size (inches)

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allows for modeling additional system behavior. Among those are diurnal pressure
variation, water age, chlorine residual, and system stability.

A pipe network computer model must be calibrated before it can be relied on to
accurately simulate distribution system performance. Calibration is a comparison of the
computer results, field tests, and actual system performance. Field test data can be
obtained by performing fire flow tests and pressure tests on the system. System
performance data can be obtained by reviewing SCADA data. When the computer model
does not match the field tests or system performance data within an acceptable level of
accuracy, the computer model is adjusted to match actual conditions. Calibration is
especially useful for identifying pipe sizes that are not correct and isolation valves that
are not operating properly. Pipe roughness is an additional characteristic which may be
adjusted during calibration. The FWC model was calibrated using fire flow tests and
SCADA data and adjustments were made so that the overall behavior of network was
reproduced within the model. Calibration results are included in Appendix E. The overall
flow patterns in the model matched the observed values very well.

Three computer models were developed for this study. The first was a model of the
existing system (existing model). This model was used for calibration and to identify
deficiencies in the existing system. A second model was developed which was used to
identify those corrections necessary to address the existing system deficiencies (corrected
existing model). The third phase was the development of a future model to indicate those
improvements that will be necessary for the projected future conditions (future model).
Development of the future model is presented within Section 3.0.

Performance of the water system was evaluated under three main operating conditions:
low flow (highest pressure) conditions, peak hour conditions, and maximum day plus fire
flow conditions. Each of these conditions put the water system into a worst-case situation
so the performance of the distribution system may be analyzed for compliance with DEQ
and FWC’s requirements. The model results for each of the conditions are discussed
below.

The maximum observed pressure under low flow conditions occurs at the far southwest
corner system (corner of Maurine Drive and Jill Street). The highest pressure observed
was 93 psi. The DEQ standard for maximum pressures is 100 psi; therefore, the FWC
system is deemed compliant and no recommendations are needed.

An evaluation of peak hour conditions as shown in Figure 4, illustrate that peak
instantaneous flows reach about 10,600 gpm. The current well capacity of all sources is
about 10,500 gpm. Under high demand conditions, more flow can be provided at the
expense of pressure. As system pressure drops, the operating point of the well sources
drifts to the right on their pump curves and flow increases. Under present conditions with
all sources operating, the minimum pressure occurs in the far northeast corner of the
system and is 45 psi. However, in order to account for redundancy, the analysis was
repeated with the system’s largest source, Well #9, offline. Under those conditions,
minimum pressures at the same location dropped to 12 psi.

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The maximum day plus fire flow scenario was evaluated by simulating a 1,500 gpm fire
suppression demand at each model node while concurrently imposing maximum day
demand on the system. Additionally, higher fire flows were tested at select nodes based
on fire flow requirements provided by the Idaho Surveying & Rating Bureau (see
Appendix F). In general, the system performed very well and was able to meet fire flow
requirements throughout most of the system. Locations that were not able to meet fire
flow requirements were recorded and projects were developed in order to address the
deficiencies. Model files are included on a CD in Appendix G
Drinking Water Quality
Water age and water quality were also modeled as part of this study. Figure 6 presents a
plot of the modeling results for water age and Figure 7 presents the results for chlorine. In
general, the two plots have an inverse relationship. Areas with lower age have a higher
chlorine residual while areas with a higher age have a lower residual. Isolated nodes with
high age and low residual located about the periphery of the system may be a result of
modeling artifacts. Demand placement is often not perfect, and a dead-end pipeline with
no demand will show high water age in the model due to minor inaccuracies in demand
placement. However, in many cases these nodes are in areas that have not yet developed,
and it is likely that stagnant water exists in some of these pipelines. Still, nearly all the
water in the system has an age of less than 10 hours. The low water age is largely a by-
product of having no system storage. Similarly, most of the system has a chlorine
concentration between 0.1 and 0.2 mg/L. One exception that is not located around the
periphery of the system can be seen in the areas near Wells #1, #6, and #7. Those wells
do not include chlorination and their influence can be seen as a low chlorine “bubble” is
formed when the wells operate. The overall performance of the system with respect to
water quality is very good.
Energy Use
Costs associated with energy are a significant portion of the operating budget for many
water utilities. Pumping energy was investigated for each of Falls Water Company’s
sources. Table 2 provides a summary of energy use for FWC sources.

Table 2 – Energy Use of FWC Sources
Source
2018 Annual
Water Volume
(MG)
Energy
Use
(kWhr)
Obs. Energy
Intensity
(kWhr/MG)
Expected Energy
Intensity
(kWhr/MG)
Difference
Well 1 83.3 102,443 1,230 970 9%
Well 2
352.6 470,400 1,334 1,050 23% Well 4
Well 6
Well 7
Well 5 116.2 120,406 1,036 1,200 -12%
Well 8 179.5 321,392 1,791 1,590 -1%
Well 9 582.3 1,201,280 2,063 1,650 5%
Well 10 211.8 354,840 1,676 1,330 1%

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Figure 6 – Water Age Modeling Results

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Figure 7 – Chlorine Modeling Results

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In addition, Table 2 provides a framework for FWC to select the order of priority for
pump usage. In general, a pump with a lower energy intensity will provide water at a
lower cost than a pump with a higher energy intensity.

Energy use was determined based on metered use from power bills. The energy use was
corrected by reviewing monthly bills during months where no water was pumped. Energy
used in the months with no pumping was considered base load for maintaining lights,
heat, etc. at the pump station. The base load was subtracted from each month in order to
isolate the energy associated specifically with pumping. Energy intensity is the amount of
energy in kilowatt hours that is used to pump one million gallons of water. Observed
energy intensity was calculated using production data and energy bills. Expected energy
intensity is a theoretical value calculated based on pumping depth, system pressure at the
well location, and pump efficiency. Wells #2, #4, #6, and #7 all receive energy from
same power meter and are combined as a result. Most of the observed values were very
close to the expected values. The largest differences occurred at the combined Wells #2,
#4, #6, and #7 and at Well #5. The most likely causes for the differences between
observed and expected energy intensities are inaccuracies in pumping efficiencies and
pumping level. Large discrepancies should be investigated. Replacing a pump with a
worn impeller has the potential to save money by reducing energy use.
Pertinent Operation and Maintenance Issues and Concerns
A few general observations were made in reviewing the performance of the FWC system.
First, FWC is approaching the upper limit of the areas they can serve while maintaining
the system as a single pressure zone. Maximum pressures at the lower elevations within
the system approach 95 psi, while minimum pressures at the higher elevations drop near
45 psi. Diurnal pressure variation is currently about 25 psi during a high demand summer
day.

Reducing diurnal variation would increase the level of service while also reducing
customer complaints. Additionally, it would provide some ability to serve elevations
higher than presently served by the system. The highest elevations currently served by
FWC are about 4,785 feet. With a preference to maintain 50 psi, elevations of about
4,797 feet could be served if the diurnal pressure variation was reduced to 15 psi. The
diurnal variation in demand can be attributed to two factors: headloss between source and
demand locations and pumps exceeding normal operating capacities to meet peak hour
demands.

A review of the model data shows that the transmission capacity of the system is
generally adequate. Flow velocities for nearly all pipes are less than 5 fps during peak
hour flow. As a result, very little would be gained towards reducing diurnal pressure
variation by increasing pipeline sizes. The largest improvements in limiting diurnal
pressure variation would come from increasing source capacity.

One additional observation made while building the FWC model is that the system
operation is somewhat unstable. As outline above, the general pattern of operation is to
use VFDs at Well #9 and Well #1 to maintain pressure and then turn on additional pumps
as pressure drops due to increased demands. Table 3 presents a list of FWC well control
settings from February 2019.

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Table 3 – FWC Well Settings
Well1 Elevation
(ft)
VFD Pressure
Setting (psi)
VFD HGL
Setting (ft)
On Setting
(psi)
On HGL
(ft)
Off Setting
(psi)
Off HGL
(ft)
Well #1 4,736 73 4,904.5 65 4,886.0 - -
Well #2 4,740 - - 58 4,873.8 84 4,933.8
Well #4 4,740 - - 69 4,899.2 81 4,926.9
Well #5 4,752 - - 64 4,899.7 79 4,934.3
Well #6 4,740 - - 67 4,894.6 82 4,929.2
Well #7 4,740 - - 65 4,890.0 79 4,922.3
Well #8 4,748 - - 65 4,898.0 91 4,958.0
Well #9 4,760 70 4,921.5 60 4,898.5 - -
1. As of February 2019, Well #10 was not included in the electronic readout of SCADA settings and for this
reason is not included on this list.

Wells #9 and #1 are not turned off with a pressure control, but instead when the flow is
below 300 gpm and 200 gpm, respectively. Therefore, once turned on these wells will
remain running until demand is low, with Well #9 being the last well to turn off due to
the higher HGL of its pressure setting. As shown, 6 of the 8 wells are set to turn on at
HGL settings between 4,890 ft and 4,898.5 feet, a fairly small range of less than 4 psi
change in pressure. However, because there is no storage in the system, small changes in
demand can result in large changes in pressure. Additionally, as demonstrated in Figure
4, rapid changes in demand occur between 7:00 AM and 8:00 AM (ramping down) and
between 5:30 PM and 7:30 PM (ramping up). The susceptibility of the system to pressure
changes along with the rapid demand changes combine to create conditions where
multiple wells can be triggered to turn on or off at nearly the same time. However,
modeling shows that triggering multiple wells at the same time can push pressures high
enough such that the conditions for the wells turning back off are met. As a result, the
system becomes unstable.

FWC has reported that they have observed periods where wells have cycled on and off
and have needed to place the wells in “manual” mode to avoid the cycling. One option
that was investigated for more stable system operation was to link the on/off settings to
the flow of the VFD controlled wells instead of system pressure. The general framework
would be to run Wells #9 and #1 with a pressure setting similarly to existing conditions.
Auxiliary wells would be controlled based on the flow of the VFD wells. They would be
set up to turn on in sequence just before the capacity of the VFD wells was maximized.
For example, using Well #9 as the control well, Well #5 would turn on as the flow in
Well #9 was approaching 2700 gpm. Well #5 turning on would then reduce the flow
coming from Well #9. When Well #9 began to approach 2700 gpm again due to
increasing demands, Well #4 could then be turned on. This general pattern could be
followed until all the wells were active and then reversed to shut wells down as demands
dropped. As a side benefit, this type of configuration would also reduce the diurnal
pressure change. Under present conditions with pressure control, nearly 10 psi of pressure
drop is allowed to occur before additional sources are activated. With a system based on
pressure control, the drop in pressure is necessary for stability. However, changing to
flow-based control does not have the same limitations and sources could be activated
before system pressure begins to drop.

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Cross-connection Control Program
FWC does not currently have an active cross-connection control program. We recommend
that, through survey or field inspection or both, a database be prepared to identify possible
cross connection problems. Armed with this data, FWC will be prepared to design a cross
connection control plan that fits their needs. Selections from the Rules that describe the
basic components of a cross control program are given in Appendix H.
Water Audit
A brief water audit was performed in order to determine the amount of water that is not
accounted for via billing. The total annual production based on meter data from each of
the Wells is 1.35 billion gallons. Summing the flows from the individual billing meters
gives a total volume of 1.24 billion gallons, a difference of about 8%. Included in this 8%
value are water losses due to pipeline leaks, meter inaccuracies, construction water, fire
hydrant flushing, etc. Experience suggests that a difference of 8% between production
and billed water is very good, and better than most systems are able to manage.
2.4 Violations of Safe Drinking Water Act and Rules for Public Drinking
Water Systems
No violations of the safe drinking water act or rule for public drinking water system have been
noted within the past 5 years. Water quality test results along with a copy of Falls Water
Company’s 2019 Consumer Confidence Report is included in Appendix D.
2.5 Sanitary Survey
A copy of the FWC 2015 sanitary survey is provided in Appendix B. No significant
deficiencies were identified. Deficiencies that were recognized include threaded spigots on
well discharge piping to the distribution system, needing a meter on Well #7, and needing a
screen on the pump to waste at Well #6. At this time, all these deficiencies have been
corrected.
2.6 Existing Deficiencies
Throughout the analysis of the existing system, deficiencies have been noted and recorded. A
listing of the existing deficiencies is presented in Table 4.

Table 4 – Existing Deficiencies
Deficiency Location
Source capacity (3,000 gpm) Systemwide
Low pressures under peak day demands Northeast corner of system
Fire flow capacity less than 1,500 gpm 4328 Cochise Drive and 4625 East Botanical
Drive
Fire flow capacity less than 1,500 gpm Taylors Crossing Charter School
Fire flow capacity less than 1,500 gpm 1139 Payette River Road
Fire flow capacity less than 1,500 gpm 4800 N Yellowstone Highway
Fire flow capacity less than 1,500 gpm
and eliminate dead end pipeline.
3273 East Kit Lane
Looping and pipeline interconnectivity Along 25th East between 2695 North and Iona
Road and along Iona Road between 2844 East
and 1572 East

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Deficiency Location
Looping and pipeline interconnectivity Ammon Road between Pearce Drive and
Greenwillow Lane
Looping and pipeline interconnectivity Ammon Road between Greenwillow Lane and
O’Bryant Street
Looping and pipeline interconnectivity Farnsworth Drive and Dixie Street
Transmission capacity Between Wells 2, 4, and 6 and Monte Vista
Avenue
Transmission capacity Along 1st Street
Transmission capacity Along 1st Street
Asbestos cement pipes Eastern portion of Fallsbrook Mobile Home
Court
Water right capacity Systemwide

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3.0 FUTURE CONDITIONS
3.1 Future Growth
Table 5 shows historic population and growth for Falls Water Company and Bonneville
County.

Table 5 – Historical Growth of Falls Water Company and Bonneville County
Year FWC
Connections
Estimated FWC
Service Area
Population1
Bonneville County
Population
1960 75 225 46,906
1970 218 654 52,457
1980 1,109 3,327 65,980
1990 1,359 4,077 72,207
2000 2,081 6,243 82,522
2010 4,125 12,375 104,234
2018 5,804 17,412 116,854
1. Service area population estimated as 3 people per connection.

Falls Water Company’s service area is not congruent with a City or other political division for
which population data is available. For this reason, historical growth is most readily available
in terms of connections. As an estimate, the population within the service area was calculated
as 3 people for each connection. Average annual growth for FWC since 2000 is about 5.9%.
Growth in Bonneville county during the same time period has averaged about 2.0%.
Bonneville Metropolitan Planning Organization has prepared future population projections for
Bonneville County which predict a county wide growth rate of 1.02% through 2040.

Although Falls Water Company’s population growth since 2000 has been strong, it is
expected that growth will be slower over the coming ~20 years. Falls Water Company is
pressing up against several boundaries that will impact growth. Figure 8 highlights those
boundaries and shows the areas where future growth, in terms of EDUs, was allocated. As
shown, Falls Water Company’s southern boundary is adjacent to the City of Ammon and no
further growth will occur to the south. There are still areas where growth can occur to the east
and west, but the extent of the growth in those directions is limited based on the current and
planned boundaries for the cities of Idaho Falls and Iona, respectively. In addition, the service
area boundary agreed to between the Iona Bonneville Sewer District (IBSD) and Idaho Falls
is shown. Falls Water Company customers have historically received sewer service from
IBSD. However, IBSD has agreements in place with the City of Idaho Falls which limit the
extent of their service area. Limits on the IBSD service area serve as de facto limits on the
Falls Water Company service area. Adjustments to the existing agreements would be needed
for IBSD to serve areas outside of the extent shown in Figure 8.

Aside from the demographic and political boundaries mentioned above, there is a physical
boundary associated with elevation. Based on the current pressure in the system, the highest
elevation that can be served while maintaining a minimum of 50 psi through the system is
4,797 feet when diurnal pressure variation is limited to 15 psi. For reference, the 4,800-foot
elevation contour is bolded in Figure 8.
FALLS WATER COMPANY
PROJECTED GROWTH
FIGURE 8
Falls Water Company
20-Year Planning Area
Ammon
Idaho Falls
Iona
IBSD-IF Agreement Boundary
20-Year Growth Areas (EDUs)
10-foot Elevation Contour
(4,800-foot Contour Bolded)
Planned Future Boundary
Ammon
Idaho Falls
Legend
U.S. Hwy 26
N
25th East
ID Hwy 43
Ammon Rd
1st St
15th East
Crowley Rd
Lincoln Rd
Iona Rd
49th North

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18030 Falls Water Company Facility Planning Study 23

Based on these limiting factors it is believed that growth in the Falls Water Company service
area will be faster than in the county as a whole, but slower than the growth previously
experienced. A historical comparison of the Falls Water Company growth to growth within
Bonneville county shows that Falls water company has grown at a rate of about three times
higher than the county. County growth projections through 2040 are just over 1%. Our 2040
projections reflect this historical trend and are based on a growth rate of 3.0%. Therefore, it is
projected that 9,990 EDUs will be served in 2040.
3.2 Forecast of Demand
Residential, Commercial and Industrial
The predominant growth in the area is urban residential. Some industrial and commercial
growth has occurred around 25th East and along U.S. Highway 26 northeast of Idaho
Falls in the county. Growth of a commercial nature is manifesting itself along Ammon-
Lincoln Road as well. Potential future service areas were identified by meeting with Falls
Water Company staff. After identifying the potential service areas, land use was
generally defined as either residential, commercial, or industrial. Demands were
calculated for each future service area based on land use type and acreage. Residential
demands were allocated based on 2.65 units per gross acreage. This density was selected
by counting the density of homes within several of the newer subdivisions within the
Falls Water Company service area. Residential demand was then projected by calculating
the total new residential units and multiplying that number by the demand per EDU
(average day, maximum day, and peak hour). Non-residential demands were calculated
based on acreage and demand density. Non-residential demand densities were determined
by reviewing Falls Water Company billing data and past experience in analyzing water
usage.

Depending on the type of business, non-residential use can vary widely. However, within
the context of a water distribution system, the wide variations in individual usage become
less important as the high and low users average out. Based on the reviewed data a
demand density of 1.5 gpm/gross acreage was used for projecting water use in areas
projected to develop with non-residential land uses.

The general procedure in projecting growth was to allocate demand at the described
densities to the currently undeveloped areas that were judged most likely to become
developed by 2040. The process of adding EDU’s incrementally was continued until the
2040 target of 9,990 EDUs was reached.
Project Average Day Demand, Maximum day Demand and Peak Hour
Demand
Based on the process described above, a comparison of existing and projected future
demand characteristics is presented in Table 6.
Adequacy of Water System Fire Flow Capacity
As referenced previously, a listing of fire flow requirements as determined by the Idaho
Surveying & Rating Bureau is included in Appendix F. The property with the highest fire
flow requirement is Smith RV at 1523 North 25th East with a rating of 4,000 gpm. Under
the future maximum day plus fire flow scenario, the required flow is 17,394 gpm.
Hydraulic analysis for this scenario is presented below.

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Table 6 – Projected Future Demands
Criteria Existing 2040
EDUs 5,370 9,990
Average Day Flow (gpm) 2,570 4,781
Maximum Day Flow (gpm) 7,200 13,394
Max Day/Avg Day Ratio 2.8 2.8
Peak Hour Flow (gpm) 10,579 19,681
Peak Hour/Avg Day Ratio 4.1 4.1
Peak Hour/Maximum Day Ratio 1.5 1.5
Average Daily Flow/EDU, gpm 0.48 0.48
Peak Hour Flow/EDU, gpm 1.97 1.97
3.3 User Charges and Operations and Maintenance Budget
Falls Water Company’s rate structure is mandated by the Idaho Public Utilities Commission
(IPUC). For 3/4-inch and 5/8-in meters, the monthly minimum charge is $17.75 which
includes up to 12,000 gallons of water. For water used above 12,000 gallons, there is an
excess use charge of $0.689 per thousand gallons.

A Falls Water Company revenue and expense detail for the 2018 has been included with
Appendix I. Operating expenses for that year totaled just under $1.2 million.
3.4 Hydraulic Model Analysis
A computer model of the FWC’s future water distribution system was developed by starting
with the “corrected existing model” referenced previously, and adding the demands associated
with the future system. Demands were added at the locations identified for growth and model
transmission pipes and nodes were added in order to facilitate the additions. The same diurnal
curve was used for the future model as was used in the existing model and the model was set
to run as an extended period simulation.

Performance of the future water system was evaluated under the same three operating
conditions as the existing model (low flow conditions, peak hour conditions, and maximum
day plus fire flow conditions), but with the updated future demands. Through an iterative
process, system facilities were upgraded so that minimum operating criteria were met. The
evaluation criteria were as follows:

• 100 psi maximum pressure
• 50 psi minimum pressure during peak hour (system preference)
• 20 psi minimum pressure during maximum day plus fire flow

As a general summary, no modifications were needed in order to meet the maximum pressure
criterion. Source and transmission projects were both needed to meet the criterion of 50 psi
during peak hour. No additional projects beyond those needed to meet the peak hour criterion
were needed in order to meet the projected future fire flow requirements. A listing of
recommended future facilities is outlined in Section 3.5.

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3.5 Drinking Water Improvements needed for a Minimum 20-year period
Throughout the planning process, facility improvements have been identified that will be
needed within the Falls Water Company system during the coming 20 years. Upcoming
projects can further be classified according to the immediacy of need. Improvements that
address existing deficiencies are included in Table 7, Table 8, and Table 9.

Table 7 – Projects Addressing Existing Deficiencies
ID Purpose Location Solution
A-1 Low pressures under
peak day demands
Northeast corner of
system
New Well #1 with assumed capacity of 1,500
gpm
A-2 Fire flow capacity
less than 1,500 gpm
4328 Cochise Drive
and 4625 East
Botanical Drive
Install 1,790 feet of 8-inch pipe in Crowley
Road between 1st Street and John Adams
Parkway. Install 60 feet of 8-inch pipe in
Coachise road to connect to existing 6-inch
pipe.1
A-3 Fire flow capacity
less than 1,500 gpm
Taylors Crossing
Charter School
Install 320 feet of 12-inch pipe in Lincoln
Road between 4743 E and Wood River Road.
A-4 Fire flow capacity
less than 1,500 gpm
1139 Payette River
Road
Install 520 feet of 8-inch pipe in Fall River
Road between Gemmet Creek Drive and
Madison River Road.
A-5 Fire flow capacity
less than 1,500 gpm
4800 N Yellowstone
Highway
Install 1,040 feet of 8-inch pipeline in Edwards
Drive between Ammon Road and 3424 E
Edwards Drive and 180 feet of 8-inch pipe
northward into the adjacent circle.
A-6
Fire flow capacity
less than 1,500 gpm
and eliminate dead
end pipeline.
3273 East Kit Lane Install 770 feet of 8-inch pipeline in Harding
Lane between Kit Lane and 1st Street.
A-7
Looping, pipeline
interconnectivity,
and provide
transmission
capacity for new
well in Project A-1
25th East between
2695 North and Iona
Road; Iona Road
between 2844 East
and 1572 East
Install 5,884 feet of 12-inch pipeline in 25th
East between 2695 North and Iona Road and in
Iona Road between 2844 East and 1572 East
A-8
Looping and
pipeline
interconnectivity
Ammon Road
between Pearce Drive
and Greenwillow
Lane
Install 1,300 feet of 12-inch pipe in Ammon
Road between Pearce Drive and Greenwillow
Lane.
A-9
Looping and
pipeline
interconnectivity
Ammon Road
between Greenwillow
Lane and O’Bryant
Street
Install 1,080 feet of 10-inch pipeline in
Ammon Road between Greenwillow Lane and
O’Bryant Street.
A-10
Looping and
pipeline
interconnectivity
Farnsworth Drive and
Dixie Street
Install 160 feet of 10-inch pipe in Dixie Street
between Farnsworth Drive and 4386 Dixie
Street
A-11
Improve
transmission
capacity
Between Wells 2, 4,
and 6 and Monte
Vista Avenue
Install 280 feet of 12-inch pipeline between
701 Eden Drive and 539 Monte Vista Avenue.

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ID Purpose Location Solution
A-12
Improve
transmission
capacity and looping
Along 1st Street Install 1,060 feet of 10-inch pipe in 1St Street
between Robison Drive and Wheatfield Lane
A-13
Improve
transmission
capacity and looping
Along 1st Street Install 1,240 feet of 10-inch pipe in 1St Street
between Ammon Road and Nassau Drive
A-14
to
A-19
Replace existing
asbestos cement
pipes
Eastern portion of
Fallsbrook Mobile
Home Court
Install 7,790 feet in Upland Street, Lakewood
Avenue, Jensen Drive, Contor Avenue,
Crawford Street, North Adams Drive, and
Mobile Drive
A-20 Increase water right
capacity N/A
Increase the volumetric water right capacity by
at least 535 acre-feet and the diversion rate by
3,170 gpm
A-21 Improve system
stability N/A Reconfigure the SCADA system control of
pump start and stop triggers
1. Segment between Cochise Drive and John Adams Parkway can be omitted if existing
pipeline in Belle Arbor Drive can be connected through to 1st Street as a result of
development progress.
Table 8 – Alternative 1 with Storage Tank
ID Project Description
B-1 Storage Tank #1
Build new 2.0 MG storage tank adjacent to Well 9 site. Re-equip Well
9 for pumping directly to storage tank and install direct pipeline
connection. Re-equip Well 5 for pumping directly to storage tank and
install direct pipeline connection.
B-2 Booster Pump
Station #1
Construct a new booster pump station adjacent to Storage Tank #1 with
a capacity of 5,500 gpm.
B-3 Pipeline Upgrades
Pipeline upgrades will be needed around new tank to facilitate higher
flows. Anticipated pipeline improvements:
• 1,070 feet of 10-inch pipe in Vision Drive
• 290 feet of 12-inch pipe in Ammon Road between Deloy
Avenue and Michelle Street
• Additional upgrades to pipeline in immediate vicinity of booster
pump station – 390 feet of 20-inch pipe, 290 feet of 16-inch pipe

Table 9 – Alternative 2 with Additional Well and No Storage Tank
ID Project Description
C-1 New Well #2 New well with assumed capacity of 1,500 gpm

Projects A-1 through A-7, and A-20 are the highest priority as they directly address
shortcomings identified within the existing system. Projects A-8 through A-19 and A-21 also
address existing shortcomings but provide more indirect benefits. As a result, these projects
should be considered a lower priority. The “B” (Alternative 1, Table 8) and “C” (Alternative
2, Table 9) projects represent two alternatives. The system analysis identified that an
additional 3,000 gpm of source capacity is needed under existing conditions. Project A-1 is
assumed to supply 1,500 gpm of capacity. The additional 1,500 gpm capacity could be met by
constructing a new storage tank and booster pump station as outlined by the “B” projects, or

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by adding an additional well as outlined by the “C” project. Discussion regarding the relative
merits of each alternative is included within Section 4.0.

Table 10 provides a listing of the recommended future projects.

Table 10 – Projects Addressing Future Deficiencies
ID Project Description
D-1 New Wells Approximately 9,000 gpm of additional source capacity will need to be
added within 20 years.1
D-2 Storage Tank #2 Build new 1.0 MG storage tank adjacent to Well #2 Site. re-equip Wells
#2 and #4 to pump directly to the storage tank.
D-3 Booster Pump
Station #2
Construct a new booster pump station adjacent to Storage Tank #2 with
a capacity of 3,000 gpm.2
D-4
Improve
transmission
capacity and looping
along Crowley Road
Install 2,380 feet of 12-inch pipe in Crowley Road between
Greenwillow Lane and 1st Street
D-5
Improve
transmission
capacity and looping
along Iona Road
Install 2,350 feet of 12-inch pipe in Iona Road between Pinnacle Drive
and 3452 East Iona Road
D-6
Improve
transmission
capacity along
Monte Vista Avenue
Install 1,620 feet of 12-inch pipe in Monte Vista Avenue between 558
Monte Vista Avenue and 1st Street2
D-7 Purchase additional
water rights
Increase the volumetric water right capacity by 3,600 acre-feet and the
diversion rate by 9,100 gpm
1. Assumes one of the following will be implemented to address existing needs: 1,500 gpm of existing source
capacity and a storage tank will be added; or 2,000 gpm source capacity will be added with no storage tank.
2. This project is contingent on adding a 2nd storage tank near the location of Well 2.

In listing the future projects, it is assumed that all the “A” existing projects will be completed
along with either the Alternative 1 or Alternative 2 projects. Moreover, projects D-2, D-3, and
D-6 are associated with adding a storage tank adjacent to the existing Well #2 site. These
should be viewed similarly to the existing projects categorized as Alternatives 1 and 2. A tank
is not strictly necessary, and the peak hour capacity of the tank could be replaced by an
additional 1,000 gpm of well capacity. Projects addressing existing deficiencies should be
completed within the next zero to five years, while projects addressing future needs should be
evaluated periodically and constructed as needed. A map of the recommended projects is
shown on Figure 9.

Several transmission lines were identified as developer driven pipelines. Those pipelines were
also sized for future demands and the locations of the pipelines are included on Figure 9.
Table 11 presents a summary of the total length of 10-inch and 12-inch developer driven
pipelines that are projected to be added by 2040. In the case of the developer driven pipelines,
projects have not been defined beyond providing pipeline locations and sizes. It is expected
that developers will pay for and construct these pipelines, and they have been included within
the planning document to facilitate proper sizing.

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Table 11 – Developer Driven Transmission Pipeline Lengths
Size Length (ft)
10-inch 770
12-inch 5,220

FALLS WATER COMPANY
RECOMMENDED PROJECTS
FIGURE 9
Existing Wells
Future Tanks
Future Booster Pump Stations
Existing FWC Pipes
2-inch
4-inch
6-inch
8-inch
10-inch
12-inch
Pipeline Projects
8-inch
10-inch
12-inch
16-inch
20-inch
Developer Pipeline Projects
10-inch
12-inch
Legend
U.S. Hwy 26
N
25th East
B-1, B-2, & B-3
Ammon Rd
1st St
15th East
A-13
ID Hwy 43
Crowley Rd
D-2 & D-3
Lincoln Rd
A-14 to A-19
Iona Rd
49th North

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4.0 DEVELOPMENT AND INITIAL SCREENING OF ALTERNATIVES
4.1 Problems/Deficiencies with the Existing Water System
Existing deficiencies can be place into four basic categories: source capacity, fire flow
capacity, looping and pipeline interconnectivity, transmission capacity, and asbestos-cement
pipes. A brief discussion of each category is included.

The deficiency in source capacity is primarily related to a lack of source redundancy.
Redundancy is needed so that no single source is indispensable to system operation.
Currently, Well #9 is FWC’s largest source. If Well #9 were to fail during the summer, FWC
would not be able to meet DEQ minimum pressure standards due to a lack of capacity. Source
capacity can be increased in two ways: either the construction of additional wells, or by
adding a storage facility and booster pump station. Discussion between these two alternatives
is included Section 4.2.7.

Several fire flow deficiencies were identified within the existing system. Increasing source
capacity has a positive effect on fire suppression flow; however, the most direct and
economical way to increase fire flow capacity is to increase local pipeline capacity. This can
be accomplished by upsizing pipes or increasing system interconnectivity and looping.
Increasing pipeline interconnectivity is the preferred method where feasible. It often requires
less pipeline length while providing the added benefit of eliminating dead-end pipelines.
Recommendations for projects addressing fire flows were formulated accordingly.

Projects recommended to increase looping and pipeline interconnectivity carry similar
benefits to those specified to increase transmission capacity. Both projects aid in reducing
pipeline flow velocities. Reducing pipeline velocities helps to control pressure variation
during peak flows. Reducing pressure variation improves the level of service within the
system and will allow Falls Water Company to serve water to a higher elevation while still
meeting minimum pressure guidelines. Looping of distribution lines has the added benefit of
improving water circulation. This helps eliminate dead end lines that are potential locations
for stagnant water and sediments which reduces potential for developing bacteria in the
system.

Deteriorating asbestos-cement pipes can allow asbestos fibers into drinking water.
Additionally, the aging pipes are brittle and prone to breakage. For these reasons it is
recommended that the remaining asbestos cement pipes in the FWC be replaced.

In summary, projects have been identified in order to address each of the identified
deficiencies. Source capacity is the principal area in which multiple viable options exist for
meeting system requirements. Options to address fire flow, looping, pipeline
interconnectivity, and asbestos-cement pipe replacement are more limited. A discussion of
project alternatives and estimated budgetary costs are included within the following sections.

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4.2 Development of Alternatives
Discussion of No Action Alternative
The no action alternative would be to continue to operate the system as it now stands.
Currently, FWC would be unable to meet minimum pressure requirements if Well #9
were to suffer a failure during peak demand periods. In addition, several areas in the
system are not able to meet fire flow requirements and peak service elevations are limited
due to diurnal pressure variation of about 25 psi. Failure to address these issues would
result in non-compliance with DEQ regulations and diminished level of service to
customers.
Discussion of Optimum Operation of Existing Facilities
As noted in Section 2.3.8, the automation of the current system is somewhat unstable.
This instability was originally observed via modeling and subsequently confirmed
through conversations with FWC staff. The primary evidence that the system was
unstable was in pumps frequently turning on and off and generally large pressure swings.
A restructuring of the Well on/off controls was found to result in improved stability while
also reducing diurnal pressure variation. Refer to the discussion in Section 2.3.8 for a
more detailed discussion.
Discussion of Regionalization
The Cities of Idaho Falls, Ammon, and Iona are adjacent to the Falls Water Company
service area. At present none have expressed interest in absorbing Falls Water
Company’s distribution system. Regardless, Falls Water Company is privately owned and
has no interest in exiting the drinking water utility business. There are several small
private water systems adjacent to and in some cases within the Falls Water Company
service area including: Honeybee Acres, Bonneville Acres, Autumn Cove Mobile Home
Court, and Pinewood Estates. Falls Water Company is interested in absorbing the
distribution infrastructure of small local water providers where feasible, and would
welcome Bonneville County, DEQ, and IPUC support in doing so.
Existing Projects with Limited Alternatives
Due to operational constraints and system geometry many of the projects that were
identified to address existing deficiencies do not have viable and economical alternatives.
These projects were grouped together as “A-series” projects, and budgetary cost
estimates are included in Table 12.

A detailed cost estimate is provided for each item in Appendix A.

In order to fully bring the system into compliance with DEQ standards as well as meet
the level of service requirements preferred by Falls Water Company, it is recommended
that each of these A-series projects be completed.

Projects A-2 through A-19 address localized issues related to fire flow capacity, looping
and interconnectivity, and asbestos cements pipes. Project A-20 increases water right
capacity to meet short term growth projections. Project A-21 improves the operation of
the system by reducing diurnal pressure fluctuation and eliminating system instability.

Project A-1 partially addresses FWC’s source capacity deficiency by adding 1,500 gpm.
In all, 3,000 gpm of additional source capacity is needed. The remaining 1,500 gpm of

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Table 12 – Budgetary Cost Estimates for Existing Projects with Limited
Alternatives
ID Project Description Estimated Cost
A-1 Ryan Anderson Development Well $771,700
A-2 Crowley Road from 1st Street to John Adams Pkwy (8" Extension) $319,000
A-3 Lincoln Road from 4743 E to Wood River Road (12" Extension) $70,500
A-4 Replace 6" Pipe in Fall River Road with 8" Pipe $72,900
A-5 Replace 6" Pipe in Edwards Drive with 8" Pipe $183,300
A-6 Harding Lane from Kit Lane to 1st Street (8" Extension) $95,900
A-7 25th East and Iona Road Waterline Extensions $1,233,800
A-8 Ammon Road from Pearce Drive to Greenwillow Drive (12"
Extension) $147,800
A-9 Ammon Road from Greenwillow Drive to O'Bryant Street (10"
Extension) $187,200
A-10 Replace 6" Pipe in Dixie Street with 10" Pipe $42,600
A-11 Replace 8" Pipe East of Well 2 with 12" Pipe $37,400
A-12 First Street from Robison Drive to Wheatfield Lane (10"
Extension) $245,100
A-13 First Street from Ammon Road to Nassau Drive (10" Extension) $278,800
A-14 Fallsbrook asbestos cement pipes - Lakewood Street and Upland
Street $411,900
A-15 Fallsbrook asbestos cement pipes - Jensen Drive $141,900
A-16 Fallsbrook asbestos cement pipes - Contor Avenue $454,800
A-17 Fallsbrook asbestos cement pipes - Crawford Street $131,100
A-18 Fallsbrook asbestos cement pipes - North Adams Drive $166,500
A-19 Fallsbrook asbestos cement pipes - Mobile Drive $67,400
A-20 Increase the volumetric water right capacity by at least 535 acre-
feet and the diversion rate by 3,170 gpm $1,230,500
A-21 Reconfigure the SCADA system control of pump start and stop
triggers $34,500
TOTAL $6,324,600

source capacity would be supplied by projects outlined as Alternative 1 or Alternative 2
within the following sections.
Alternative 1 – Construct Storage Tank Adjacent to Well #9 Site
One option to provide the remaining source capacity is Alternative 1, the construction of
a new on grade storage facility adjacent to the existing Well #9 site. Some preliminary
consideration was given to the construction of an elevated storage tank. Elevated storage
that allows gravity flow into the system is very beneficial. Gravity flow tanks help to
control pressure transients and help promote stable system operation. Although there are
inherent advantages associated with an elevated storage tank, that option was rejected due
to high costs. Instead, on-grade storage was identified as a more cost-effective solution
that would meet FWC’s needs.

Construction of an on-grade storage facility will also require construction of a new
booster pump station along with pipeline upgrades in the area of the new tank to
accommodate the increased flows associated with the booster pump station. Based on
preliminary work, a 2.0 MG tank is recommended. Hydraulic modeling of the future

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2040 system shows that 1.4 MG of equalization storage will be utilized based on future
projected demands, flows from Wells #5 and #9, and FWC’s diurnal demand curve.
Sizing the tank to 2.0 MG will allow 0.5 MG to be set aside as fire/emergency storage
with an additional 0.1 MG for operational storage. Construction of a new 2.0 MG storage
tank along with the booster pump station and pipeline upgrades will increase the
combined peak hour capacity of Wells #5 and #9 from 3,500 gpm to 5,500 gpm, an
increase of 2,000 gpm. Capital costs for the Alternative 1 projects are summarized in
Table 13.

Table 13 – Alternative 1 Capital Cost Summary
ID Project Description Estimated Cost
B-1 New 2.0 MG Storage Tank $2,517,200
B-2 New Booster Pump Station with 5,500 gpm capacity $426,700
B-3 New Tank Pipeline Upgrades $367,800
TOTAL $3,311,700

A detailed cost estimate is provided for each item in Appendix A.
Alternative 2 – Additional Well and No Storage Tank
An additional option is for Falls Water Company to continue to meet all demand
requirements through the construction of wells. Alternative 2 assumes that a new well
with a capacity of 1,500 gpm will be constructed in addition to the well project A-1 in
order to meet existing demand requirements. The estimated cost for the new well is
$674,000 and a detailed cost estimate is included in Appendix A.
Comparison of Alternatives 1 and 2
In a comparison of capital costs, Alternative 2 is roughly 20% of the cost of Alternative 1
and is the runaway winner on a purely cost basis. In addition to the high cost of the
storage facility, the costs associated with Alternative 1 are further inflated by the
additional need for a booster pump station and the pipeline upgrades that will be needed
to convey the high flows away from the new tank. Nonetheless, there are large
advantages associated with Alternative 1. Two primary advantages are reducing peak
water right diversion rate and improving system reliability. A discussion of the
advantages associated with constructing a storage tank follows.

Using a storage facility to meet peak hour flows has the benefit of reducing the system’s
peak diversion rate. The equalization storage in the tank allows the sources to pump at a
constant rate while the booster pump station ramps up and down to cycle between low-
and high-flow periods. The net reduction on diversion rate is equivalent to the difference
between the capacity of booster pump station system and the combined well capacity. In
this case, the peaking ability is projected to be 2,000 gpm (5,500 gpm - 3,500 gpm).
Thus, the diversion rate would be reduced by 2,000 gpm, or about 4.5 cfs. As a result,
construction of a storage tank and booster pump station would have the benefit of
delaying the need to increase the diversion rate associated with water rights. It should be
noted however that while using a storage tank provides benefits to the diversion rate,
there is no effect regarding annual pumped volume.

Another benefit to constructing a storage tank is improved reliability as compared to a
well. The booster pump station would be constructed with a redundant pump so that even

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if a pump failed, full capacity of the booster station would be maintained. Moreover, in
the event of failure, booster pump repair is more straightforward and less costly as all
parts are located above ground. Repairs to a well pumping system require more
specialized equipment if the pump needs to be pulled. Failure of the well itself may also
require replacing the entire well, a process that would take months. Using a booster pump
station does not completely protect a system from the failure of a well. For example, if a
well feeding a storage tank and booster pump station failed, the capacity of the booster
pump station would be negatively impacted. However, the impact of well failure on the
capacity of a booster station could be nullified by allowing water from the system to
backfeed into the tank. This would allow the booster pump station to operate at full
capacity, at the expense of additional pumping costs. Still, under an emergency scenario
the flexibility would be beneficial.

A storage tank also eliminates sanding issues for wells that pump directly into the tank.
The tank provides an area for sand to settle which can then be removed periodically. The
flow that would be gained from a storage tank and booster pump station is also
guaranteed. In drilling a well, the final capacity of the well is not known until the well is
complete. For example, in comparing the two alternatives an assumption was made that
wells would be constructed that would produce 1,500 gpm. However, in practice the well
is likely to produce from 1,000 to 2,000 gpm with higher and lower capacities also
possible.

A large capacity booster pump station provides benefits to system stability. Rather than
meeting demands by cycling multiple smaller wells on and off throughout the day, the
system is more stable and pressures more consistent using a VFD controlled booster
pump station pumping from a tank. The pump station can produce more flow than any
single well and adding a VFD pressure control allows the pump station to ramp up and
down to meet the changing demand conditions.
4.3 Discussion of Treatment Requirements for New or Upgraded
Facilities
Falls Water Company currently provides chlorine disinfection at six sources and sand separators
at four sources. It is anticipated that this general trend will continue and that all new sources
will include disinfection and that some will require sand separators. The water quality produced
by FWC wells is very high quality and no other considerations for treatment are needed at this
time.
4.4 Storage, Pumping and Pressure Requirements
Falls Water Company does not currently have any storage or booster pump station facilities.
Instead their system is configured so that all demand scenarios are met via pumping of well
sources. Falls Water Company prefers to maintain a minimum pressure of 50 psi. The highest
elevations are in the northeast corner of the system. Maintaining pressures of 50 psi in the
northeast corner result in minimum pressures of about 80 psi in the far southwest corner of the
system. Therefore, the minimum pressure for a given location in the system will range from
50 to 80 psi depending on elevation. Currently, pressures at the uppermost elevations within
the system dip to around 40 psi; however, modeling shows that 50 psi can be maintained with

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the recommended infrastructure improvements and reconfiguring of system controls. Adding
storage as outlined in Alternative 1 would have the benefits
4.5 Separate Irrigation Facilities
FWC currently does not have separate irrigation facilities for lawn watering and outdoor use.
To accomplish such a project, a completely dual system using canal water rights would have to
be constructed. FWC does not own any surface water rights. The capital costs of installing such
a system and would be extremely high. We do not see this as an alternative for Falls Water
Company.
4.6 Staged Distribution
There is no need for staged distribution in Falls Water Company as the entire distribution
system is one pressure zone.
4.7 Environmental Impacts Associated with all Alternatives
Several of the distribution lines recommended herein are in areas where waterlines do not
currently exist. However, these areas have been disturbed by canal, road, farm and railroad
activities. At the draft stage of this facility plan, there are no known environmental impacts
associated with the alternatives given in this section.
4.8 System Classification and Operator Licensure
The system is currently classified as a Class III water system. Since all sources are
groundwater not requiring treatment of any kind except for chlorine disinfection FWC does
not need to be operated by an operator qualified for water treatment. No alternative discussed
in this chapter will change system classification or operator licensing requirements. A copy of
the Idaho Drinking Water System Classification Worksheet is included in Appendix J.

FWC’s licensed distribution system operator is Tony Wise, Class III, License DWD3–21515.
Nathan Riblett, Class III, License DWD3-22750 is FWC’s licensed substitute water operator.

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5.0 FINAL SCREENING OF PRINCIPAL ALTERNATIVES
Throughout this report the Falls Water Company system has been analyzed and projects have
been identified to address existing deficiencies as well as to prepare the system to meet the future
needs of customers. The identified projects have been separated into four categories: A, B, C,
and D. The “A” projects address existing deficiencies, and all are recommended in order to meet
minimum service standards and provide high quality drinking water service. The “B” and “C”
projects represent two alternatives. Combining one of these alternatives with the “A” projects is
sufficient to meet minimum level of service standards and Falls Water Company’s level of
service preferences. The “D” projects are outlined to plan for future growth within the system.
Cost summaries for these project alternatives are presented next.
5.1 Evaluation of Costs
Table 14 presents a summary of the existing project costs including Alternative 1.

Table 14 - Existing Project Costs with Alternative 1
ID Project Description Estimated Cost
A-1 Ryan Anderson Development Well $771,700
A-2 Crowley Road from 1st Street to John Adams Pkwy (8" Extension) $319,000
A-3 Lincoln Road from 4743 E to Wood River Road (12" Extension) $70,500
A-4 Replace 6" Pipe in Fall River Road with 8" Pipe $72,900
A-5 Replace 6" Pipe in Edwards Drive with 8" Pipe $183,300
A-6 Harding Lane from Kit Lane to 1st Street (8" Extension) $95,900
A-7 25th East and Iona Road Waterline Extensions $1,233,800
A-8 Ammon Road from Pearce Drive to Greenwillow Drive (12" Extension) $147,800
A-9 Ammon Road from Greenwillow Drive to O'Bryant Street (10"
Extension) $187,200
A-10 Replace 6" Pipe in Dixie Street with 10" Pipe $42,600
A-11 Replace 8" Pipe East of Well 2 with 12" Pipe $37,400
A-12 First Street from Robison Drive to Wheatfield Lane (10" Extension) $245,100
A-13 First Street from Ammon Road to Nassau Drive (10" Extension) $278,800
A-14 Fallsbrook asbestos cement pipes - Lakewood Street and Upland Street $411,900
A-15 Fallsbrook asbestos cement pipes - Jensen Drive $141,900
A-16 Fallsbrook asbestos cement pipes - Contor Avenue $454,800
A-17 Fallsbrook asbestos cement pipes - Crawford Street $131,100
A-18 Fallsbrook asbestos cement pipes - North Adams Drive $166,500
A-19 Fallsbrook asbestos cement pipes - Mobile Drive $67,400
A-20 Increase the volumetric water right capacity by at least 535 acre-feet and
the diversion rate by 3,170 gpm $1,230,500
A-21 Reconfigure the SCADA system control of pump start and stop triggers $34,500
B-1 New 2.0 MG Storage Tank $2,517,200
B-2 New Booster Pump Station with 5,500 gpm capacity $426,700
B-3 New Tank Pipeline Upgrades $367,800
TOTAL $9,636,300

Table 15 presents a summary of the existing project costs including Alternative 2.

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Table 15 - Existing Project Costs with Alternative 2
ID Project Description Estimated Cost
A-1 Ryan Anderson Development Well $771,700
A-2 Crowley Road from 1st Street to John Adams Pkwy (8" Extension) $319,000
A-3 Lincoln Road from 4743 E to Wood River Road (12" Extension) $70,500
A-4 Replace 6" Pipe in Fall River Road with 8" Pipe $72,900
A-5 Replace 6" Pipe in Edwards Drive with 8" Pipe $183,300
A-6 Harding Lane from Kit Lane to 1st Street (8" Extension) $95,900
A-7 25th East and Iona Road Waterline Extensions $1,233,800
A-8 Ammon Road from Pearce Drive to Greenwillow Drive (12" Extension) $147,800
A-9 Ammon Road from Greenwillow Drive to O'Bryant Street (10"
Extension) $187,200
A-10 Replace 6" Pipe in Dixie Street with 10" Pipe $42,600
A-11 Replace 8" Pipe East of Well 2 with 12" Pipe $37,400
A-12 First Street from Robison Drive to Wheatfield Lane (10" Extension) $245,100
A-13 First Street from Ammon Road to Nassau Drive (10" Extension) $278,800
A-14 Fallsbrook asbestos cement pipes - Lakewood Street and Upland Street $411,900
A-15 Fallsbrook asbestos cement pipes - Jensen Drive $141,900
A-16 Fallsbrook asbestos cement pipes - Contor Avenue $454,800
A-17 Fallsbrook asbestos cement pipes - Crawford Street $131,100
A-18 Fallsbrook asbestos cement pipes - North Adams Drive $166,500
A-19 Fallsbrook asbestos cement pipes - Mobile Drive $67,400
A-20 Increase the volumetric water right capacity by at least 535 acre-feet and
the diversion rate by 3,170 gpm $1,230,500
A-21 Reconfigure the SCADA system control of pump start and stop triggers $34,500
C-1 New Well in Northeast Area of System $674,100
TOTAL $7,096,300

Table 16 presents a summary of future 20-year projected costs.

Table 16 – 20-Year Future Projects Costs
ID Project Description Estimated Cost
D-1 New Wells with about 9,000 gpm Capacity $4,629,900
D-2 New 1.0 MG Storage Tank $1,280,000
D-3 New Booster Pump Station with 3,000 gpm capacity $365,700
D-4 Crowley Road from Green Willow Lane to John Adams Pkwy (12"
Extension) $424,800
D-5 Iona Road from Pinnacle Drive to 3452 Iona Road (12" Extension) $392,200
D-6 Replace 6" Pipe in Monte Vista Avenue with 12" Pipe $262,900
D-7 Increase the volumetric water right capacity by 3,600 acre-feet and the
diversion rate by 9,100 gpm $8,280,000
TOTAL $15,635,500

Detailed cost estimates for each of the projects listed in Table 14, Table 17, and Table 16 are
included in Appendix A. Regarding existing project costs, Alternative 2 is clearly the lowest cost
solution. However, while Alternative 1 has higher costs, benefits to the system are also larger.
While it is difficult to assess the monetary value of the benefits of adding a storage tank, it is

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believed that they are large enough to justify the increased expense. Final determination of the
best option will depend on Falls Water Company preferences and availability of funding.
5.2 Consideration of any Impacts to Water Supply Systems
The recommended projects would not impact other water supply systems. As new wells are
drilled, potential impacts on individual wells located near the selected well sites will need to be
considered.
5.3 Comparison of Alternatives by Providing a Broad-Brush
Environmental Analysis
At this point, environmental impacts of these projects have not been determined. However, a
few observations can be made at this time. First, distribution pipes recommended for installation
in this report would be laid in roads or alongside roads in developed areas. Next, the potential
storage tank would be constructed on the existing Well #9 site. Well sites are also expected to
be situated within new developments. Therefore, it is expected that environmental impacts will
be limited to areas that have already by impacted.

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6.0 SELECTED ALTERNATIVE AND IMPLEMENTATION
6.1 Justification and Detailed Description of Recommended Alternative
Based on the preceding analysis and feedback from Falls Water Company personnel, it is
recommended that Falls Water Company proceed with implementation of the Alternative 1
projects. This will include completion of “A” and “B” projects as outlined in Table 14.
Included in those projects are one drinking water well, 18 pipeline installation projects, one
water right acquisition project, one SCADA improvement project, and a storage tank/booster
pump station facility. Future projects, as shown in Table 16, should be periodically evaluated
for need. These projects fall into a five to 20-year planning horizon. Future projects are
provided for the purpose of planning and budgeting. However, since the future projects are
not expected to be constructed for several years, the remainder of this report will focus on the
existing projects.
6.2 Preliminary Design of Recommended Alternative
Schematics of the Selected Plan
Refer to Figure 9 for a map of the recommended projects.
Proposed Design Criteria
The preliminary design criteria based on the existing projects associated with Alternative
1 are as follows:

• Project A-1, new drinking water well: Pump design of 1,500 gpm at 380 feet
TDH.
• Projects A-2 through A-19 and project B-3, pipeline improvement projects:
Pipeline lengths and sizes as shown in Table 7 and Table 8.
• Project A-20, water right acquisition: Acquire water rights to increase the
volumetric water right capacity by at least 535 acre-feet and the diversion rate by
3,170 gpm in order to plan for immediate needs within the next three years.
• Project A-21, reconfigure SCADA control: Adjust SCADA control as described
in Section 2.3.8 to improve system stability and reduce daily pressure
fluctuations.
• Project B-1, new storage tank: Construct a 2.0 MG storage tank to provide 1.4
MG of equalization storage, 0.5 MG of fire flow/emergency storage, and 0.1 MG
of operational storage.
• Project B-2, new booster pump station: Construct a new booster pump station to
pump from the storage tank into the system. Preliminary design of the booster
station is for three pumps, each with a capacity of 2,750 gpm. Accounting for
pump redundancy, the design flow would be 5,500 gpm at 175 feet TDH.

This study does not attempt to decide which construction type is preferable for the storage
tank. The final decision should be made as part of a preliminary engineering report or as
part of the bid process.
Design and Construction Completion Schedule
An implementation schedule has not yet been adopted by Falls Water Company. However,
because the Alternative 1 projects address existing deficiencies, it is recommended that

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they be completed as soon as practicable. Projects A-1 through A-6 should be considered
the highest priority as they address source capacity and fire flow issues. Projects A-13
through A-20 and B-1 through B-3 are intermediate in priority. These projects provide
tangible benefits to the system, but the potential consequences for a delay in completing
these projects is not as great as the highest priority projects. Projects A-7 through A-12
address looping and pipeline interconnectivity and should be considered the lowest
priority.
6.3 Justification of Recommended Alternative
The selected Alternative 1 will deliver much benefit to Falls Water Company. Although costs
associated with Alternative 1 are higher than Alternative 2 the additional benefits justify the
increase. A listing of the primary benefits versus constructing only additional wells is as
follows:

• Flow increase of 2,000 gpm associated with a tank is larger than the expected 1,500 gpm
flow from a new well.
• Flow from the storage tank will not require a corresponding increase is water right
diversion rate.
• The flow provided by a storage tank and booster pump station is guaranteed, as opposed
to a well which has an unknow flow until it is completed.
• Booster pumps provide flow more reliably due to redundancy and cost less to repair and
maintain.
• A storage tank will help reduce sand in the system by providing a capture point where
sand can be removed.
• Hydraulic modeling demonstrates that a large capacity booster station improves stability
by reducing the number of individual small wells turning on and off throughout the day
to meet changing demand conditions.
6.4 Total Project Cost Estimate
The total cost of existing projects in Alternative 1 is $9,636,300. The total cost of future
recommended projects is $15,635,500. Combined, the projected costs for system
improvements during the coming 20-year period is $25,271,800. Of that total, the single
largest contributor is water right purchases. Between existing and future recommendations,
the projected cost to obtain water rights through approximately 2040 is $9,510,500. Due to the
outsized contribution of water rights to the total cost, it is apparent that Falls Water Company
should be particularly diligent in planning and managing their water right portfolio.
Expected Monthly Charges
A full analysis of the recommended project’s impact on user charges is beyond the scope
of this work. As a private for-profit utility, Falls Water Company’s rates are set under
direction from the Idaho Public Utilities Commission.
6.5 Owner’s Capability to Finance and Manage Projects
FWC has demonstrated through past projects its ability to finance capital improvements and
bring projects such as the proposed herein to fruition.

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6.6 Availability of the Most Suitable Land
FWC has been diligent in planning for future system needs. As a result, land has already been
purchased that would allow for the construction of storage tanks next to Wells #9 and #2.

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REFERENCES

Bonneville Metropolitan Planning Organization

IDAPA 58.01.08

USDA Soil Conservation Service. "Soil Survey of Bonneville County, Idaho." 1979.