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Commission Memorandum
REPORT TO: Honorable Mayor and City Commission
FROM: Bob Murray, Project Engineer
Chris Kukulski, City Manager
SUBJECT: Water Facility Plan
MEETING DATE: June 12, 2006
BACKGROUND: The City has undertaken the task of updating its facility plans. The team
of Allied Engineering Services, Inc/Robert Peccia and Associates was selected for the Water
plan. The draft plan has now been completed and is ready for review and comment. Attached is
a copy of the executive summary for the document which will be the basis of the presentation to
the Commission. This meeting will be for the Commission to discuss and review the findings of
the plan with the consultant. A subsequent public hearing will be held on the 26th.
RECOMMENDATION: Listen to presentation; ask questions for clarification, discussion.
FISCAL EFFECTS: N/A
ALTERNATIVES: None
Respectfully submitted,
_________________________________ ____________________________
Robert J. Murray Jr., Project Engineer Chris A. Kukulski, City Manager
Attachments: Easement Documents
Report compiled on 6/7/2006
Executive Summary Section 1
City of Bozeman
Water Facility Plan
1
INTRODUCTION
During the last decade, the City of Bozeman has experienced record growth. Over the next
20 years population growth is expected to average five percent. With a population of 33,450
in 2005, the population is expected to reach 88,700 by the year 2025. The increase in
population will create greater demands on the City’s water infrastructure including source,
treatment, distribution and storage. Allied Engineering Services, Inc., in conjunction with
Robert Peccia and Associates and BETA Engineering, was commissioned with the task of
completing a 20-year Water Facility Plan to evaluate the condition of the existing water
system, analyze alternatives for improvements, and make recommendations along with
providing estimated costs. The results of the study will be used as the basis for creating the
City’s Capital Improvement Plan.
SYSTEM DESCRIPTION, NEEDS AND DEFICIENCIES
Water Supply/Water Rights
Within the planning period for this document (2006 – 2026), the City may see a shortfall in
its water supply unless steps are taken to acquire additional water rights and/or water sources.
Based on the analysis presented in Section 3.C. and the population projections for the City
presented in Chapter 2, the following conclusions regarding the adequacy of the City’s water
supply can be made:
1. The City’s projected usage is estimated to exceed the currently owned water
rights sometime between 2020 and 2025. In 2025, the estimated water system
usage is 5,504 million gallons per year (MGY) and the total of the City’s
currently available water rights is 5,261 MGY.
2. The City’s projected usage is estimated to exceed the reliable yield of its
sources between 2015 and 2020. The reliable yield is defined as “the
maximum quantity of water which can be guaranteed during a critical dry
period.” (Linsley and Franzini, 1979, Water-Resources Engineering, pg. 150).
The City’s estimated reliable yield from its existing water sources is 3,530
MGY. The City’s estimated usage in 2015 is 3,384 MGY and in 2020 is
4,314 MGY.
Other issues with the City’s existing water rights are summarized below:
1. The point of diversion for two of the Sourdough Creek water rights is below
the City’s existing Sourdough intake, making these rights unavailable. These
two rights can provide a total of 77 MGY.
2. Lyman Creek and spring flows exceed the maximum allowed withdrawal rate
specified in the City’s Lyman Creek water rights during the spring and early
summer months. During the late fall and winter months, Lyman Creek and
the Lyman Spring flows are less than the allowed withdrawal rate.
Executive Summary Section 1
City of Bozeman
Water Facility Plan
2
3. The City has approximately 2,886 MGY of impoundment water rights on the
Sourdough drainage that cannot be used unless a storage reservoir is
constructed to replace the breached Mystic Lake dam.
4. The use of the “Lichtenberg Rights” on Hyalite Creek is limited to three short
time periods during the late spring and summer months.
Executive Summary Section 1
City of Bozeman
Water Facility Plan
The report recommends a number of steps that the City can consider in order to increase its
water rights and water supply. These steps are summarized in Table 1 below:
Table 1 – Actions to Increase Water Supply and Water Rights
Action Comments Feasibility/Issues
Purchase additional stored water
rights in Hyalite Reservoir and
additional in-stream water rights.
City will have to monitor the
available rights and purchase
them when they become
available. 1,624 MGY of stored
rights in Hyalite Reservoir are
potentially available.
Difficult to determine when rights will
become available. Must have a willing
seller. Obtaining Hyalite stored rights is
one of the best means to increase the City’s
water supply. Will be costly.
Increase Water Treatment Plant
Efficiency
The existing plant’s efficiency
drops to 70% during spring
runoff. The proposed new
treatment plant will increase
efficiency by 90% to 95%.
Will require the construction of a new
treatment plant.
Modify Lyman Creek Rights to allow
higher withdrawal rates during high
summer demand periods. The total
year withdrawal volume can not be
exceeded, but more water would be
available when it is needed most.
In Lyman Creek there is more
water available during the
summer than the City’s
allowable withdrawal rate. In
the winter there is less flow than
the allowable withdrawal rate.
A water rights attorney must be consulted
to determine legal feasibility. A long-term
flow-monitoring program must be
implemented to provide data to modify the
water right.
Modify Lichtenberg Rights on
Hyalite Creek (98 MGY) to expand
period of use.
The time of use for these rights
is restricted to three windows in
the summer. (May 25-June 10,
June 25-July 10 & Aug. 1 to
Aug 10)
It may be possible to convert these rights
to stored rights that can be used anytime.
A water rights attorney must be consulted
to determine legal feasibility.
Implement water conservation
measures as outlined in the 2002 City
of Bozeman Water Conservation
Study
A successful water conservation
program can reduce system
demands significantly allowing
existing sources to serve a
larger population.
The public must be educated through
media advertising and informational flyers
included with water bills.
Construct a new Mystic Lake Dam to
replace the dam that was breached
due to dam safety regulations.
The City owns 1,995 MGY of
stored rights for Mystic Lake,
with an additional 931 MGY of
stored rights reserved in
Sourdough Creek.
Environmental and permitting
requirements will be difficult for the dam.
However, the City should pursue all
avenues for construction of the dam to
avoid losing these water rights. It may
also be possible to use some of these stored
rights during spring runoff by modifying
the right, but a water rights attorney must
be consulted to determine the feasibility.
Change the point of diversion on the
two Sourdough rights that are located
below the existing Sourdough intake
Modifying the point of diversion should be
feasible after submitting the required
application to DNRC.
Modify “Story Mill” rights. This right was historically used
for power generation and was
converted to an irrigation right.
DNRC indicated that conversion of this
right to a municipal right is not possible.
However, the City should consult with a
water rights attorney to determine the
feasibility.
Pursue Development of Groundwater
Sources
A number of high volume wells
have been developed NW of the
City. Groundwater wells could
provide a year-round reliable
supplemental water supply.
A thorough groundwater hydrogeological
study must be completed to evaluate
aquifer yields, optimum well locations,
water rights issues and surface water
connectivity.
Condemnation of Water Rights Recommended only as a last resort. Can
be costly, time consuming and will have a
negative public relations impact.
3
Executive Summary Section 1
City of Bozeman
Water Facility Plan
4
Before implementing any of the above actions that would require modifying or obtaining
water rights, the City should consult with a water rights attorney to determine the feasibility
of the actions and prioritize them accordingly.
In addition to the actions summarized in Table 1 above, it is recommended that the City re-
evaluate the reliable yield hydrology for the City’s existing water sources. Current estimates
indicate that the reliable yield from the City’s water sources is 67 percent of the City’s
contracted and permitted water rights. As discussed above, the City’s water demand may
exceed the reliable yield from its sources by as early as 2015. However, this reliable yield
percentage is based on limited flow data for the City’s water sources. A long-term flow-
monitoring program should be implemented for all of the City’s sources. As the flow data
accumulates, the reliable yield percentage can accurately be re-calculated. The last water
system master plan completed in 1997 indicated that the actual reliable yield may be greater
than current data indicates. If a greater reliable yield can be calculated, based on long-term
flow monitoring, the current predicted shortfall could be extended further into the future.
Also, there is currently a 20 percent shrinkage factor (due to evaporation and seepage losses)
imposed on the City’s stored water rights in Hyalite Reservoir. A long-term flow-monitoring
program on Hyalite Creek may allow the reduction of this shrinkage factor, making more
water available.
Treatment
Hyalite/Sourdough
The city of Bozeman has historically relied on water from its Hyalite and Sourdough sources
for 90 percent of its supply. Water is diverted from intakes on Hyalite and Sourdough
Creeks, and conveyed through gravity transmission mains to the existing water treatment
plant (WTP).
Constructed in 1983, the WTP uses a direct filtration process to capitalize on the low
turbidity typical of Hyalite and Sourdough Creek waters during most of the year. The
original plant included twin flocculation basins and eight dual-media filter units. In 1993,
treatment capacity was expanded to 15 MGD with the addition of four filters, each paired
with its own flocculation basin. Coagulant feed, fluoridation, and chlorination facilities are
provided. The treatment system is housed in a single-story insulated metal building.
The Hyalite transmission main has just been replaced and intake improvements are
underway. The Sourdough intake was reconstructed and the upper half of this transmission
main was replaced in 2002. A new Connection Building with pressure reducing valves was
recently constructed at the WTP site in conjunction with the Hyalite improvements. Once all
new Hyalite improvements are completed later this year, remaining needs relative to raw
water facilities primarily involve screen icing and hydraulic problems at the Sourdough
intake (screening) building. Forecasting and lead time for raw water releases from Hyalite
Reservoir also result in periodic raw water “overflows” at the plant, and wasted water.
Executive Summary Section 1
City of Bozeman
Water Facility Plan
5
The WTP has remained in regulatory compliance, but faces three primary limitations:
1. Key components, especially mechanized equipment and the building structure,
are nearing the end of their useful lives.
2. While effective most of the year, the direct filtration treatment process is
marginal when raw water turbidity is high during spring runoff or flash
thunderstorms in the watersheds. Frequent filter backwashes drop plant
efficiency as low as 70 percent, reducing effective capacity to 10.5 MGD.
3. Rapid population growth and resulting water demands are already at the
current WTP capacity during peak day use. Plant capacity is especially
marginal when high raw water turbidity periods overlap with high consumer
demand in early summer.
Critical component problems at the WTP include substandard flocculation and hydraulic
imbalances in the original eight-filter train, seasonal filter air binding, marginal filter-to-
waste capability, and aging pumps in critical service for backwash handling. Chemical feed
deficiencies include hazards and equipment obsolescence with existing (dry) fluoride feed
and (gas) chlorination systems. Antiquated instrumentation and controls and limited ability
for automated process operation pose additional plant constraints. Building deficiencies
include inadequate floor space for equipment access, substandard HVAC, and deteriorated
insulation and metal paneling.
Lyman Creek System
The existing Lyman Creek System consists of a groundwater (spring) collection system
located at the head end of Lyman Creek and approximately 12,000 feet of gravity
transmission piping that connects the spring collector to a disinfection building and 5.0
million gallon storage reservoir located north of Bozeman. There are a number of problems
and deficiencies associated with this system that have been identified in detail in Section 3.A.
A summary of the problems associated with the Lyman system is provided below:
1. The surface water flow in Lyman Creek cannot be utilized without
constructing a surface water treatment plant.
2. The maximum flow from the Lyman Creek spring cannot be utilized due to
undersized process piping located in the existing disinfection building. A
significant amount spring flow overflows to the creek and cannot be used due
to restrictions in the system process piping.
3. Flow leaving the spring collector is controlled by valves in the disinfection
building 12,000 feet away. Operators must regulate flows at the disinfection
building to be less than the spring yield to prevent air from entering the
transmission main. If air enters the transmission main, it impairs the
performance of the pressure reducing valves located along the main.
Executive Summary Section 1
City of Bozeman
Water Facility Plan
6
Impaired performance of the pressure reducing valves could cause high-
pressure conditions in the main or a reduction in flow.
4. A lack of adequate flow monitoring and telemetry equipment makes it
difficult for operators to regulate and monitor system flows. There is no
electronic communication between the spring site and the disinfection
building. Electrical power is not available at the spring site.
5. A “municipal watershed” designation is needed from the Forest Service to
enhance the protection of the Lyman supply.
6. Wintertime access to the raw water transmission pipeline and spring collector
is difficult, hindering operation and maintenance.
7. Miscellaneous improvements are needed to improve the performance of the
chlorine and fluoride chemical feed systems and the flow monitoring system
for the Lyman source.
Miscellaneous site improvements are needed to improve access for chemical deliveries and
remedy icing problems in the outlet control-building stairwell.
Distribution and Storage
The City of Bozeman currently serves customers with a gravity supplied water system. One
booster station is active in the system which is capable of pumping from the North to the
South pressure zones; however, operation of this booster station is not necessary for water
distribution. Treated surface water is stored in four separate reservoirs (including the WTP
clear well). The four storage reservoirs have a combined capacity of 12.1 MG. The water
distribution system is comprised of approximately 200 miles of transmission mains and
laterals. Distribution mains are constructed of Ductile Iron and Cast Iron pipe, with Ductile
Iron pipe being the City’s required material for all new construction. Pipe sizes range from 4
to 30 inches. There are three pressure zones which are separated and controlled by 14
Pressure Reducing Valves (PRV’s). PRV’s are installed to maintain a maximum operating
pressure of 120 psi. The three pressure zones are referred to as the south, north and
northwest zones. The City of Bozeman utilizes radio read meters to register usage by
customers and generate revenue.
The study period for this Facility Plan was 2000 through 2004. Water usage data gathered
over this time period showed an average per capita water usage of 165.4 gpcd. The study
period showed an average population growth of 3.5 percent, whereas water consumption rose
only 2.5 percent during this same period. The data indicates some water conservation has
been taking place either through reduced usage, reduction in leakage, more accurate meter
readings, or a combination of all. The mean maximum day to average day ratio for the five-
year period was calculated to be 2.12 and the peak hour to average day ratio on the max day
is 2.93. Recommended average day usage, max day and peak hour ratios for the 20-year
planning period are 170 gpcd, 2.3 and 3.0, respectively.
Executive Summary Section 1
City of Bozeman
Water Facility Plan
Figure 1 shows the distribution of water usage by user type for the year 2003. Residential
irrigation water usage during the summer months is approximately 18 percent of the annual
water usage.
Figure 1 - 2003 Water Use Distribution by User Type
2003 Distribution by User Type
Residential
48%
Commercial
19%
Top 8
7%
City Irrigation
1%
MSU
11%
Unaccounted
14%
Residential
Commercial
Top 8
City Irrigation
MSU
Unaccounted
The City of Bozeman water system is generally in good condition, thanks to quality
engineering, design standards, material specifications, and an active and qualified operation
and maintenance staff. The Water Facility Plan study evaluated and identified the following
distribution and storage items for recommended improvements within the 20 year planning
period.
1. Replace and/or install new mains to meet recommended fire flow
requirements.
2. Replace aging and undersized mains.
3. Install new mains to add redundancy in the system.
4. Recommended new transmission mains to serve future growth and
development.
5. Address various maintenance items of existing storage.
6. Construct an additional storage reservoir to meet 20 year water demands.
7. Hire additional operation and maintenance staff to meet demands of growth,
and maintain quality of water system.
7
Executive Summary Section 1
City of Bozeman
Water Facility Plan
8
8. Construct an automated water fill station to increase revenue.
DESCRIPTION OF ALTERNATIVES AND PREFERRED ALTERNATIVE
Treatment
Hyalite/Sourdough
Five alternatives for upgraded Hyalite/Sourdough WTP facilities were selected for detailed
evaluation and comparison. These included: a short term upgrade of the existing WTP;
supplementing an upgraded WTP with 8 MGD of additional capacity using either a contact
adsorption clarification (CAC) or membrane filtration “peaking plant”; and new 22-MGD
CAC or membrane filtration plants ultimately expandable to 36 MGD. These alternatives
cover a range of plant capacities – from the current 15 MGD process to 23 MGD with
parallel peaking plants, to 36 MGD in ultimate capacity with replacement plants. New WTP
alternatives involving direct filtration or conventional coagulation/filtration processes were
eliminated; the former for marginal effectiveness and the latter for unnecessary complexity
and cost.
Based on these authors’ recommendations and in consultation with City Engineering and
Public Works staff, Alternative 4 – New Membrane Filter Treatment Plant has been
identified as the preferred alternative. Membrane filtration technology utilizes a synthetic
membrane with an approximate 0.1 micron pore size to positively exclude turbidity particles
and microbial contaminants. Membranes are configured as hollow tubes arranged in bundles,
and water is forced through under pressure. The proposed equipment is skid-mounted with
multiple modules (bundles) and integral controls on each unit. A new membrane plant would
be initially configured for 22 MGD capacity (seven skids), with the later addition of five
more filter skids for expansion to 36 MGD.
The new plant would include a screening tower, membrane chemical cleaning equipment, a
clearwell, a backwash waste sump, hypochlorination and fluoridation systems, and
lab/office/control rooms in an 18,800 sf main building. Separate structures include dual
gravity thickeners for backwash water, settled backwash microstrainers, and vacuum-assisted
drying beds for solids dewatering. All new facilities would be located on City-owned
property at the current plant site, and the existing WTP would remain operable during
construction.
The recommendation of this alternative is based on its superior technical feasibility for
compliance with future surface water treatment regulations and comparatively lower cost as
compared to CAC treatment. This alternative is also preferred over short-term improvements
at the existing WTP with incremental capacity expansions since it avoids $2.6 to $10.8
million in interim capitalization that would become obsolete and largely unrecoverable when
water demands exceed 23 MGD. With the preferred alternative, the initial 22 MGD plant
expenditure retains full utility when the facility is eventually expanded to 36 MGD.
Executive Summary Section 1
City of Bozeman
Water Facility Plan
9
Two aspects of membrane filtration as recommended should be noted. Membrane processes,
including the equipment supplied, are proprietary and not interchangeable amongst
competing vendors, locking the City into a sole manufacturing source. Membrane modules
are forecast to require replacement every 10 years at a future estimated cost of $1.5 million.
A rigorous 12-month pilot testing exercise is recommended ahead of plant design to confirm
and optimize the membrane filtration process parameters for the exact characteristics of
Hyalite/Sourdough raw waters. The City is required to conduct 24 months of sampling for
Cryptosporidium under the recently enacted Long Term 2 Enhanced Surface Water
Treatment Rule (LT2ESWTR). Results of these tests will dictate what future level of future
surface water treatment will be required. Testing must be completed by 2010, but with the
new Hyalite/Sourdough WTP proposed, should be conducted earlier so results can be
available ahead of plant design.
For rehabilitation of the existing WTP or construction of a new plant, disinfection
alternatives of liquid hypochlorination and ultraviolet (UV) disinfection were compared. To
meet viral inactivation regulations, post-hypochlorination would still be necessary with UV
disinfection, adding complexity and cost to that alternative. Retaining gas chlorination was
disfavored due to safety hazards, pH suppression requiring subsequent finished water
buffering, and the cost of the emergency scrubber now required for a gas cylinder storage
area. Liquid hypochlorination is recommended for disinfection and would also provide the
necessary chlorine residual.
Alternatives for raw water storage were also considered, but are likely constrained by land
availability at the required elevation to meet Hyalite/Sourdough transmission main(s)
hydraulic requirements. A 12-acre pond on a 20-acre site could provide approximately one
week of “average day” storage in the event wildfire compromised raw water quality in the
watersheds. Aesthetics and liner requirements are additional considerations for such a
facility. With its $6.2 million capital cost, this improvement remains questionable and the
City is advised to defer further deliberations pending identification of a suitable site if
available.
Improvements to offset hydraulic and screen icing problems at the Sourdough Screening
Building are also recommended and involve new telemetry, the addition of non-electrified
propane heaters, and limited underground re-piping adjacent to the flow measurement flume.
Lyman Creek System
Four alternatives for upgrading the Lyman source were considered and are summarized
below:
1. The “no action” alternative. No improvements would be made and the
system would continue to operate as it is today. Under this alternative a
portion of the City’s available water right would remain unused due to
undersized process piping and the inability to treat surface water flow from
Lyman Creek.
2. Construct a new contact adsorption clarification water treatment plant to treat
surface water from Lyman Creek.
Executive Summary Section 1
City of Bozeman
Water Facility Plan
10
3. Construct a new membrane filtration plant to treat surface water from Lyman
Creek.
4. Capture additional groundwater flow. Additional groundwater flow would be
captured by eliminating the hydraulic restrictions in the process piping and by
collecting additional groundwater flow at the spring collection system.
Currently, over 800 gpm of groundwater from the spring collection system
overflows back to the creek at certain periods of the year due to constructions
in the system piping and the inability to capture all of the flow at the spring
collection system.
The above alternatives are not necessarily mutually exclusive. For example the “no action”
alternative may have to be implemented to allow adequate design and construction time to
implement one of the other alternatives. Implementing the alternative to capture additional
groundwater flow in the near future and then implementing one of the treatment alternatives
in the future when the City must maximize all of its available water right on the Lyman
system is a long-term consideration.
Based on these author’s recommendations and in consultation with City Engineering and
Public Works staff, Alternative 4; Capture Additional Groundwater Flow has been identified
as the preferred alternative. This alternative would include improving flow-monitoring
capabilities for the Lyman System, removing the hydraulic restrictions from the process
piping, and maximizing the amount of groundwater flow captured at the spring collector site.
Miscellaneous improvements would also be made to the chemical feed system, control
system and the systems infrastructure to improve the operator’s ability to operate and
maintain the system. Once this alternative is implemented, it may be possible to utilize the
entire Lyman water right (3.8 MGD) with captured groundwater flow from the spring during
the spring and early summer months. Construction of a new surface water treatment plant
would not be implemented until the City needs to maximize the amount of water it can obtain
from the Lyman source. Because surface water flows decrease significantly in the winter
months, (down to 0.22 MGD) and because significant groundwater flows from the spring are
available during the summer months, a new water treatment plant may not be required for the
foreseeable future.
Distribution and Storage
A computer water model was constructed of the entire City’s water system to assist in
analyzing hydraulic deficiencies. The model was used to locate areas in the distribution
system with low and high pressures, inadequate fire flow, high velocities, capacity
constraints and redundancy concerns. Multiple scenarios were tested in the model to
establish recommended improvements of the distribution system over the 20-year planning
period. In addition, the model was utilized to locate and select future transmission main sizes
within the proposed study area to serve City growth over a 50-year period.
Recommendations for improvement to the water distribution system fall into the following
four categories:
Executive Summary Section 1
City of Bozeman
Water Facility Plan
11
1. Replace undersized mains and install new mains to meet recommended fire flow
requirements.
2. Replace mains smaller than eight inches in diameter and older than 100 years during
the 20 year planning period.
3. Install new mains to serve the 20 year planning area.
4. Install new mains to serve the 50 year planning area.
Approximately 34 percent of the City’s water mains are undersized by current City standards,
which require main sizes to be eight inches or greater. Undersized mains restrict water main
capacity and available fire flow. The computer water model was run on the existing water
system to identify areas which do not meet fire flow requirements. Alternatives considered
for improving the existing water system included replacement, sliplining, pipe bursting and
no action. The replacement alternative was chosen as the most logical and cost effective.
Sliplining and pipe bursting are typically used for sewer mains and water transmission mains
with few or no services. The costs of these technologies in residential and commercial areas
where services are numerous are prohibitive, therefore the replacement alternative is
recommended. Recommended improvements to the water system to meet required fire flow
for the 20-year planning period are shown in Figure 2. In general, a total of 58,626 LF of
water mains is recommended for replacement and/or new installation.
In addition to identifying water main upgrades to meet required fire flow, older mains six
inches and smaller were also identified for replacement. By the year 2025, approximately 14
percent of the City’s water mains will be over 100 years old. Aging pipe increases the
chance of water main breaks and leakage. Water main breaks interrupt service to customers
and are costly. A system inventory of water main installation dates was completed to
identify older mains. In addition, the City conducted a Water Needs Study in 1999 and
compiled a list of water mains needing replacement. This list, along with the system
inventory, was used to identify older mains needing replacement. Figure 3 shows the
location and replacement size recommendation for older main replacement. In general, a
total of 54,500 LF of older water mains are recommended for replacement.
Upgrades to the City’s water system to serve the 20 year planning area include adding new
mains to outlying areas and fixing redundancy issues. Three areas were identified as needing
redundancy in the City water system. The first and most critical is providing an alternate
transmission main from the Sourdough Water Treatment Plant (WTP) to the City. Currently,
only one 30 inch transmission main supplies water to the City from the WTP. In the event of
a main break on this line, the City would need to rely on storage to meet system demands,
which for a maximum day event in 2005 would meet needs for about 24 hours. A new 48
inch transmission main in addition to the existing 30 inch main is needed to meet the City’s
water demand needs. The new transmission main is recommended to be installed along Nash
Road, down Third Avenue to Goldenstein Lane. Looped mains serving the Laurel Glen
subdivision and East Frontage Road areas are also recommended. Figure 4 shows the
location of redundancy mains and future mains to serve the 20 year planning area.
Executive Summary Section 1
City of Bozeman
Water Facility Plan
12
Approximately 57,985 LF of water mains are proposed for fixing redundancy concerns and
another 93,231 LF of mains for future extension into the 20 year planning area.
A study area boundary was developed by HDR and Morrison/Maierle Inc. in conjunction
with the City of Bozeman staff. At the proposed development densities and population
growth rate, the study area is expected to be at full build out by the year 2055. Some areas
within the study boundary are at elevations which will not support a gravity fed system.
These areas are primarily in the northeast and southeast sections of the study area and will
require booster pumps and storage tanks to serve customers. A detailed analysis of these
areas was not completed, as City staff was not interested in constructing additional booster
pumps and storage reservoirs within the 20 year planning period. To serve future customers
in the outlying study area with water supply, a computer model of the distribution system
was constructed and analyzed to select future transmission main sizes. Main sizes were
selected based on meeting a maximum day demand of 60 MGD and a fire flow of 2500 gpm.
The recommended transmission mains for the 50 year planning area are shown in Figure 5
and include approximately 124,642 LF of mains.
Storage reservoirs are used to meet peak demands, provide fire flow, allow continued service
when the supply is interrupted, equalize system pressure and facilitate the use of economical
pipe sizes. Currently, the City has 11.3 MG of available storage, not including the clear well
at the Sourdough WTP. The Montana Department of Environmental Quality requires storage
to meet average day demand plus fire flow. The required storage for 2005 is 7.2 MG, giving
the City a surplus of 4.1 MG. However, by the year 2025, required storage for the City of
Bozeman (assuming a projected growth rate of 5 percent), will be 16.6 MG or a 5.3 MG
deficit. It is anticipated the City will exceed its available storage by the year 2017. The
recommendation is to construct and have online a single 5.3 MG reservoir at the Sourdough
WTP site by the year 2016. The benefits of constructing a single tank at the Sourdough WTP
site are threefold. First, the City currently owns adequate property at this site to construct a
new treatment plant as well as a new reservoir. Second, a higher elevation tank will allow
the City to develop further to the south of its current boundary. City growth to the south is
currently limited by low water pressure, which is supplied by the Sourdough reservoir near
Goldenstein Lane. A new reservoir at the Sourdough WTP will provide an additional 100
feet of hydraulic head or approximately 43 psi. Third, constructing a single reservoir makes
sense from an economy of scale standpoint.
Various meetings with City staff provided the following additional operation and
maintenance items, which need to be addressed over the next 20 years:
• Various maintenance items for Sourdough, Hilltop and Lyman reservoirs. (Please see
Section 3.B starting on page 22 for a complete description.)
• Add new pumps and soft starts to Pear Street booster station to increase efficiency.
• Purchase new laptop and software for water meters.
• Replace meters. 8800 meters in City system. Currently replacing 10 percent a year
and should be caught up by 2008. Meters will then need replacement every 15 years.
Executive Summary Section 1
City of Bozeman
Water Facility Plan
13
• Find and replace all galvanized services with copper services.
• Hire additional staff for the water and sewer department. Current staff is
overwhelmed with the pace of development and is falling behind on operation and
maintenance such as valve operation, hydrant flushing and inspections. An additional
half dozen Full Time Equivalent staff are needed to keep up with operation and
maintenance demands.
• Construct an automated water fill station. The current water fill station is located at
the City Shop complex and interferes with daily operations of the water department.
Water is sold on the honor system and accounted for through ticket stubs.
Constructing an automated water fill station will assist the water department with
efficiency and increase the accuracy of accounting to generate additional revenue.
Budgeting for construction of a water fill station is recommended.
• Fix water hammer problem on Oak Street in the vicinity of the Bridger Creek
Shopping Center. Pressures as high as 165 psi are recorded in this area making the
water system ultra-sensitive to water hammer. Water hammer is an event where a
shock wave of water occurs in the mains and travels at high speeds, typically
resulting in service line breaks at a customers’ property. Service line breaks expel
large quantities of water causing damage to property. The water hammer problem is
a nuisance for both the City and the customer. Additional research on how to fix this
problem is highly recommended. One solution is to install additional Pressure
Reducing Valve stations to lower the system pressure.
COSTS TO CONSTRUCT PREFERRED ALTERNATIVES
Treatment
Hyalite/Sourdough
Costs of the recommended alternative(s) for the Hyalite/Sourdough treatment system include
the following (in 2006 dollars):
• $25.4 million capital cost for new 22 MGD Hyalite/Sourdough membrane filtration
plant.
• $7.2 million capital cost for future expansion of Hyalite/Sourdough membrane
filtration plant from 22 to 36 MGD capacity.
• $1.74 million estimated annual O&M costs for new membrane filtration plant,
including existing Plant Dept. 46 staff and required WTP staff additions.
• $185,739 capital cost for telemetry, heating, and hydraulic upgrades at existing
Sourdough intake, with $9,588 in estimated additional annual O&M costs.
Executive Summary Section 1
City of Bozeman
Water Facility Plan
14
• Plus additional one-time cost for LT2ESWTR source water sampling, estimated at
$60,000 with optional testing of Lyman Creek for future treatment.
Lyman Creek System
The estimated cost for the recommended alternative for the Lyman Creek System (Capture
Additional Groundwater Flow) is $673,000. This cost includes upgrading the existing piping
to eliminate the hydraulic restrictions in the system, installation of a new control and
monitoring system, installation of electrical service to the spring collector site and upgrading
the flow monitoring system.
Distribution and Storage
The following costs for water distribution system recommendations include construction,
engineering, inspection and a 20 percent contingency:
• Replace undersized mains and install new mains to meet recommended fire flow
requirements. A total of 58,626 linear feet of water main is recommended to be
replaced and/or added. See Figure 2 for a description of location and pipe sizes.
Total estimated cost, including pavement removal and replacement, is $12.7 million.
• Replace aging mains six inches in diameter and smaller. A total of 54,500 linear feet
of replacement main is recommended main. See Figure 3 for a description of location
and pipe sizes. Total estimated cost, including pavement removal and replacement, is
$11.8 million.
• Install new transmission mains to fix redundancy issues. A total of 57,985 linear feet
of new main is recommended. See Figure 4 for a description of location and pipe
sizes. Total estimated cost, including pavement removal and replacement, is $28.5
million. Following is a breakout cost of each redundancy area:
o New transmission main from Sourdough WTP.
19,961 LF of 48 inch main
2,636 LF of 30 inch main
2,547 LF of 16 inch main
4,525 LF of 12 inch main
Total estimated cost is $21.9 million
○ New transmission main to serve Laurel Glen subdivision
5,127 linear feet of 18 inch main
4,050 linear feet of 16 inch main
2,302 linear feet of 12 inch main
Total estimated cost is $3 million
○ New transmission main to loop East Frontage Road
7,876 linear feet of 14 inch main
7,352 linear feet of 12 inch main
Executive Summary Section 1
City of Bozeman
Water Facility Plan
15
1,609 linear feet of 10 inch main
Total estimated cost is $3.6 million
• Future mains to serve 20 year planning area. A total of 93,231 linear feet of new
water mains. See Figure 4 for a description of location and pipe sizes. Total
estimated cost, not including pavement removal and replacement, is $17.4 million.
• Future mains to serve 50 year planning area. A total of 124,642 linear feet of new
water mains. See Figure 5 for a description of location and pipe sizes. Total
estimated cost, not including pavement removal and replacement, is $25.6 million.
Total estimated cost for a 5.3 MG concrete water reservoir including engineering, inspection
and 20 percent contingency is $5.3 million.
A cost for maintenance on the three reservoirs has not been calculated due to the large
variation of items. It is recommended to solicit bids for completing the work. Bids are
currently being sought for maintenance on the Hilltop tank and are estimated to be around
$750,000. Maintenance costs on the Sourdough and Lyman Reservoir are expected to be a
smaller caliber.
Installing two new high efficiency 50 HP pumps with soft starts at the Pear Street Booster
Station will cost approximately $125,000 for design, materials and labor.
A new laptop and software for meter reading is estimated to cost $50,000. Meter
replacement is estimated to cost $100 per meter. For 8,800 meters the total cost is estimated
at $880,000.
Total estimated cost for design and construction of an automated water fill station is
$430,000.
Total estimated cost for design, construction and inspection of a Pressure Reducing Valve
station is $75,000. The number of additional PRV stations needed has not been determined.
Executive Summary Section 1
City of Bozeman
Water Facility Plan
16
IMPLEMENTATION AND SCHEDULING
Treatment
Improvements to allow increased collection of Lyman groundwater up to seasonal
maximums or the City’s 3.8 MGD water right are recommended immediately to expand
utilization of this existing source. Design is recommended to begin this year for the
upgraded Inlet Control Building piping and other improvements. Construction of these
improvements in 2007 will help offset increasing system-wide water demands until a new,
larger Hyalite/Sourdough WTP can be constructed.
Even with a proposed expansion of the Lyman groundwater supply to 3+ MGD seasonally,
peak water demands are forecast to exceed existing Hyalite/Sourdough WTP capacity within
five years. Five years is also estimated to be the minimum time frame for planning,
financing, designing, and constructing a new WTP, so those activities need to commence
shortly to assure new capacity is available when needed.
The City will need to closely monitor water demand, including both average and peak use to
determine how water demands materialize compared to projections. Any acceleration in
demands will shorten the time available for implementing new WTP facilities, while a lag in
demands may allow additional time to bring a new plant on line. The City faces a choice in
scheduling tasks for a new Hyalite/Sourdough WTP relative to whether to complete
LT2ESWTR source water testing before beginning membrane filtration pilot testing. The
two-year period required for source water testing will protract completion of a new plant
accordingly, but results may affect performance requirements for pilot testing particularly if
source water quality results in an LT2ESWTR Bin Classification greater than ‘1.’ If
monitoring of municipal water demands over the next 12 to 24 months shows any lag
compared to projected demands, consideration should be given to at least partially
completing source water testing ahead of membrane piloting.
Excluding the future expansion of a new WTP to 36 MGD, the combined $26.2 million cost
of the Lyman and Hyalite/Sourdough treatment improvements will require substantial
borrowing by the City, likely through a revenue bond issue. Annual treatment (Plant Dept.
46) O&M costs are estimated to increase by $813,000. With 20-year financing at 6.0-percent
interest, the combination of capitalization and additional O&M for recommended treatment
improvements represents an average increase of $40.44 per month per existing Bozeman
water connection (excluding any grants received). To defray the capital required, federal
grant funding of $1 to $3 million may be available from the STAG or WRDA programs,
given successful lobbying. Other state grants through the TSEP and/or DNRC Renewable
Resource Grant/Loan programs, if awarded, could provide up to $850,000.
Distribution and Storage
Considering all of the recommended improvements to the distribution system, construction of
a second transmission main from the Sourdough WTP to Goldenstein Lane is the highest
priority. The majority of the City is supplied through one transmission main from the WTP.
A closure of this main for any reason will severely disrupt water service to customers and
Executive Summary Section 1
City of Bozeman
Water Facility Plan
17
will greatly put the City at risk in terms of providing adequate fire flow. Completing a
design and securing necessary easements and funding will likely take two years and
construction another four to six months. It is recommended to start this process immediately.
The next priority items recommended are to add new mains to the Laurel Glen subdivision
and East Frontage Road areas. Looping new mains to these areas will create redundancy and
increase fire flow availability. It is recommended to begin design and construction of these
mains in the next five years.
Other upgrades to the water distribution system are not critical. It is recommended, however,
that the listed improvements be completed within the 20 year planning period. The City has
had a successful history of minimizing water main breaks; however, as older mains continue
to age the chance of water main breaks and leakage will increase. It is recommended to
begin replacing undersized and older mains on a yearly basis over the next 20 year period.
There are no areas in the City that are severely handicapped for providing needed fire flow,
but increasing available flow in key areas is recommended. Creating a priority list for main
replacement should be completed with input and consultation from City staff.
Future main construction to service the 20 and 50 year planning areas should be completed as
new developments are begun outside the City’s current limits. Typically, developers are
required to install new mains to service their developments and will be granted impact fee
credits from the City for main sizes installed over their development requirements. It is
recommended the City adopt the proposed future transmission main sizes and locations as
stated in this Plan. The proper sizes and locations will assure adequate capacity, fire flow
and pressure will be maintained.
A new 5.3 MG storage reservoir needs to be online by the year 2016, assuming the projected
growth rate remains at 5 percent. Growth rates and water demands should be monitored and
adjustments should be made to required storage volume over the next few years if necessary.
An increase in growth may require that a larger storage reservoir be constructed at an earlier
date; likewise, a decrease in growth would allow the City to postpone constructing additional
storage. At the projected growth rate of 5 percent, a 5.3 MG reservoir will serve the storage
needs for the 20 year planning period or until 2025, at which time additional storage will
need to be re-evaluated. Design, permitting and funding are expected to take two years and
construction and testing another one year, therefore, the project process should start no later
than 2013.
Maintenance repairs on the existing Sourdough, Hilltop and Lyman reservoirs should
commence immediately and be completed in the next two to three years. New pumps and
soft starts should be installed at the Pear Street booster station within the next one to two
years. Water meter replacement and new laptop and software are currently being
implemented. There are currently 8,800 water meters in the City system, which are expected
to all be replaced by the year 2008. Meters will then need to be replaced every 15 years at a
present day cost of about $100 per meter. Replacing meters is critical to maintaining
adequate revenue for the City’s water departments since old meters typically error in favor of
the customer.
Executive Summary Section 1
City of Bozeman
Water Facility Plan
Hiring additional FTE staff for the water department is recommended immediately. The
department is currently understaffed to meet the needs of the existing system and maintain
pace with growth. Attention to operation and maintenance is critical to maintaining a
healthy, fully functional water system.
Constructing an automated water fill station is recommended to increase the efficiency of the
water department and generate additional revenue from water sales to contractors. In 2005,
the City sold 4,512,095 gallons of water to private entities at $2.60 per thousand gallons, for
a total estimated revenue of $9,753. It is recommended to begin design and construction in
the next three to five years.
Fixing the water hammer problems the City is experiencing near Bridger Creek Shopping
Center is recommended to commence immediately.
SUMMARY OF PREFERRED ALTERNATIVES, COSTS AND SCHEDULE
Table 2 – Summary of Preferred Alternatives, Costs and Schedules
RECOMMENDED PREFERRED ALTERNATIVE ESTIMATED COST SCHEDULE
TREATMENT Lyman Creek System - Capture additional groundwater flow $673,000 Commence: Immediately
New 22 MGD Hyalite/Sourdough Membrane Treatment Plant $25.4 million Commence: 2007
Expansion of 22 MGD WTP to 36 MGD Plant $7.2 million To be determined
Annual O&M costs for new Membrane Treatment Plant $1.74 million Commence: 2011
Upgrades to existing Sourdough intake $185,739 Commence: Immediately
LT2ESWTR source water sampling $60,000 Commence: 2007
Total (excluding
O&M) $33.5 million
DISTRIBUTION
& STORAGE Install new Sourdough WTP transmission main $21.9 million Commence: Immediately
Install new Laurel Glen transmission main loop $3 million To be determined
Install new East Frontage Road transmission main loop $3.6 million To be determined
Replace undersize mains to meet recommended fire flow $12.7 million To be determined
Replace undersized and aging mains $11.8 million To be determined
Construct new 5.3 MG storage reservoir $5.3 million Commence: 2013
Maintenance on existing City reservoirs (Sourdough, Hilltop, Lyman) $1 to $1.3 million Commence: Immediately
New Pear Street Booster Pumps $125,000 To be determined
New meter laptop/software and meter replacement $930,000 Commence: Currently
Construct new automated water fill station $430,000 Commence: 2009
Add additional PRV stations to fix water hammer problems (2) $150,000 Commence: Immediately
Total $61.2 million
Grand Total $94.7 million
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