(Final) Kalispell WWFPU Executive SummaryTh e Kalispell WWFPU provides a guide for short-term, near-
term, and long-term capital improvements that will be the basis for
planning, fi nancing, designing, constructing, and implementating
of solutions to meet the City’s foreseeable collection system needs
for years to come. As the City cycles through the planning process,
some uncertainties and changes can be expected. However, the
approach methodology and investment the City has made in
this planning eff ort provides City staff with a proactive planning
approach for responding to future challenges and maintaining a clear
vision and consistent direction for the Utility!
SUSTAINABLE
WASTEWATER UTILITY
Prepared By:
ADVANCED ENGINEERING AND ENVIRONMENTAL SERVICES, INC.
690 N Meridian Rd, Suite 218 Kalispell, MT 59901 | (406) 257-8990
WA
S
T
E
W
A
T
E
R
Fa
c
i
l
i
t
y
P
l
a
n
U
p
d
a
t
e
Ex
e
c
u
t
i
v
e
S
u
m
m
a
r
y
JUNE 2019
93
DESIGN &
CONSTRUCTION
SUSTAINABLE
WASTEWATER UTILITY
PROACTIVE
PLANNING
UNDERSTANDING
OF THE EXISTING
SYSTEM
MODEL UPDATE
& CALIBRATION
SYSTEM
EVALUATION
CAPITAL
IMPROVEMENTS
PLANNING
INTRODUCTION
Proactively addressing system challenges is critical to ensure sustainable system
operations. Wastewater system challenges come in many forms including population
growth, aging infrastructure, increased regulatory requirements, emerging
technological trends, and eff ective capital improvements planning. Th e Wastewater
Facility Plan Update (WWFPU) provides a guide for short-term (0-5 years), near-term
(5-15 years), and long-term (15+ years) capital improvements to the City of Kalispell’s
(City) municipal wastewater collection system. Th e recommended improvements
included in the Capital Improvements Plan (CIP) will be the basis for future planning,
fi nancing, designing, constructing, and implementation of solutions to meet the City’s
collection system needs. Th is document serves as an Executive Summary to the 2019
Kalispell WWFPU report.
Short-Term CIP Project Categories &
Opinion of Probable Project Cost (OPPC)
Facility Type Existing Additional Facility Improvements
Gravity Main (Miles) 120 47 Miles of New Gravity Main Ranging 8” to 36”
Force Main (Miles) 25 10 Miles of New Force Main Ranging 4” to 12”
Lift Stations 36 21 New Lift Stations
(5 Regional with 16 Growth and Development)
Proposed Collection System Improvements to Serve FBO Conditions
Th e hydraulic model was used to develop the infrastructure necessary to serve the FBO.
A summary of improvements necessary to provide wasterwater service for the FBO planning horizon include:
$0
$2,000,000
$4,000,000
$6,000,000
$8,000,000
$10,000,000
$12,000,000
$14,000,000
$16,000,000
$18,000,000
FY 2019 FY 2020 FY 2021 FY 2022 FY 2023
Gravity & Force Main Gravity Main Lift Station Upgrades LS, Gravity & Force Main Rehabilitation & Repair
Studies Growth & Development LS & Gravity Main Optimization
::0
/LIW6WDWLRQ0DLQ,PSURYHPHQWV
::/6
5RVH&URVVLQJ:HVW,PSURYHPHQWV
::/6
/LIW6WDWLRQ ,PSURYHPHQWV
(9(5*5((1
$
(9(5*5((1
$
ttd&
$
$
)R\V/DNH
2OG5HVHUYH'5
)D
U
P
W
R
0
D
U
N
H
W
5
'
:K
L
W
H
I
L
V
K
6
W
D
J
H
5
'
)XOO%XLOG2XW $QQH[DWLRQ%RXQGDU\
:DVWHZDWHU0DLQ7\SH
)RUFH0DLQ
*UDYLW\
([LVWLQJ:DVWHZDWHU6\VWHP
:DVWHZDWHU0DLQ
:DVWHZDWHU7UHDWPHQW)DFLOLW\
/LIW6WDWLRQ
5HFRPPHQGHG:DVWHZDWHU6\VWHP
/LIW6WDWLRQ,PSURYHPHQW
&,3/LIW6WDWLRQ
5HFRPPHQGHG&,3,PSURYHPHQWV
::0/LIW6WDWLRQ0DLQ,PSURYHPHQWV
::/6/LIW6WDWLRQ ,PSURYHPHQWV
::/65RVH&URVVLQJ:HVW,PSURYHPHQWV
*URZWK 'HYHORSPHQW:DVWHZDWHU6\VWHP
:DVWHZDWHU0DLQ
Short-Term Proposed Capital Improvements
City of Kalispell WWFPU Executive Summary | Page 13
:KLWH
IL
VK5LYHU
6WL
OOZ
D
WHU
5LYHU
$VKOH\&UHHN
)OD WK HD G 5 L Y H U
ϮϮ
Ϯϵ
ϯϰ
ϭϯ
ϯϯ
ϮϬ
ϭϲ
ϱ
Ϯ
Ϯϯ
ϯϴ
ϯϱ
ϭϱ
ϴ
ϯϲ
ϭϭ
ϯϬ
ϰ
ϯ
ϭϬ
ϳ
ϭϮ
ϵ
ϯϵ
ϲ
Ϯϱ
s Z'Z E
ϭϴ
ϯϮ
ϰϭ
ϭ
ϯϳ
Ϯϭ
ϯϭ
Ϯϳ
ϰϬ
ϭϳ
ϱ
ϭϰ
ttd&
$
$
)R\V/DNH
2OG5HVHUYH'5
)D
U
P
W
R
0
D
U
N
H
W
5
'
:K
L
W
H
I
L
V
K
6
W
D
J
H
5
'
)XOO%XLOG2XW $QQH[DWLRQ%RXQGDU\
ZDWHU0DLQ7\SH
)RUFH0DLQ
*UDYLW\
J:DVWHZDWHU6\VWHP
:DVWHZDWHU7UHDWPHQW)DFLOLW\
:DVWHZDWHU/LIW6WDWLRQ
DWHU 6HUL FH $UHD
SUBSTANTIAL AREA
GROWTH
Steady growth and development will
continue to increase wastewater flows
which will require the City to upgrade
existing or add new infrastructure to
meet their future needs.
INFLOW & INFILRATION
(I/I) CONSIDERATIONS
AGING
INFRASTRUCTURE
Inflow and Infiltration also known as
I/I is a term used to describe the ways
that groundwater and stromwater
enter into a sanitary sewer system.
Currently, the City experiences I/I
which increases both peak flows and
volumes which reduces the ability
of the sanitary sewer and treatment
facilities to transport and treat
wastewater.
Portions of the City’s sanitary sewer
system are reaching their expected
useful life. The oldest portions of the
system were installed 80 years ago
and replacing those pipes is costly.
City of Kalispell WWFPU Executive Summary | Page 2
UNDERSTANDING OF THE EXISTING SYSTEM
SYSTEM CHALLENGES
Th e City’s existing wastewater collection and treatment system services approximately 22,800 people and includes
around 145 miles of sewer pipeline, 36 sewer lift stations, and an advanced wastewater treatment facility.
)XOO%XLOG2XW $QQH[DWLRQ%RXQGDU\
:DVWHZDWHU0DLQ7\SH
)RUFH0DLQ
*UDYLW\
([LVWLQJ:DVWHZDWHU6\VWHP
:DVWHZDWHU7UHDWPHQW)DFLOLW\
:DVWHZDWHU/LIW6WDWLRQ
:DVWHZDWHU6HULYFH$UHD
(YHUJUHHQ
.DOLVSHOO
City of Kalispell WWFPU Executive Summary | Page 3
PROACTIVE PLANNING
0
2,000
4,000
6,000
8,000
10,000
12,000
14,000
16,000
18,000
20,000
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
90,000
1960 1970 1980 1990 2000 2010 2016 2020 2023 2030 2033 2040 2050 2060 2068
Ac
r
e
s
D
e
v
e
l
o
p
e
d
Po
p
u
l
a
t
i
o
n
Year
Establishing Planning Periods
Th e establishment of planning periods is a critical component in the development of the
WWFPU. A total of three planning periods were established, including a short-term, near-
term, and a long-term period. For this report, full build-out (FBO) was assumed to coincide
with the Annexation Boundary policy, and as shown in the fi gure on the next page.
For this planning effort, a 2.0 percent annual growth rate is used to estimate future population projections, which is consistent with the
rate currently utilized by the City’s Planning Department. Future wastewater flows for each planning period was then calculated and
used to determine future infrastructure need and anticipated project timing.
RESIDENTIAL PLANNING DENSITIES
The City Planning Department used average
densities to assign the number of residential
DU to each area depending on future land use.
• Suburban Residential = 3 DU / Acre
• Urban Residential = 8 DU / Acre
• High-Density Residential = 10 DU / Acre
The fi gure on the following page contains the
number of added dwelling units, commercial
acres, and industrial acres for each respective
planning period.
SHORT-TERM GROWTH 0-5 YEARS (2018 – 2023)
LOOKING AT GROWTH AND FLOWS MULTIPLE WAYS
NEAR-TERM GROWTH 5-15 YEARS (2023 – 2033)
LONG-TERM GROWTH 15+ YEARS (2033-Beyond)
UNDERSTANDING FUTURE GROWTH
A collaborative approach which involved City
Planning was used to determine anticipated areas
of future growth as well as redevelopment for each
planning period. These areas identifi ed by City
Planning staff were then populated with estimated
residential dwelling units (DU) and developable
commercial and industrial acres.
Short-Term
Near-Term
Long-Term
Acres Developed Historical Population Average Annual Growth
2.00% Growth - Planning Historical Polynomial Trend
City of Kalispell WWFPU Executive Summary | Page 12
Short-Term Capital Improvement Projects Project Category OPPC
Lift Station #3 Main Improvements Gravity & Force Main $ 3,763,384
Lift Station #9 Improvements LS & Gravity Main $1,738,378
Rose Crossing West Improvements LS, Gravity & Force Main $2,081,737
Inflow and Infiltration (I/I) Study Studies $182,103
Risk-Based Sewer Rehab and Repair Projects (Total over 5 years) Rehabilitation & Repair $1,301,010
Growth and Development (Oversize Credit) Growth & Development $1,591,812
Existing City CIP "SEW 16"
(6th Alley E - South of 14th to 13th Gravity Replacement)
Rehabilitation & Repair $255,150
Existing City CIP "SEW 20"
(10" Clay Sewer Slipline in 1st Alley W. from Montana St. to Washington St.)
Rehabilitation & Repair $80,776
Existing City CIP "SEW 33"
(Manhole Rehabilitation and Sewer Main Replacements/Repairs)
Rehabilitation & Repair $260,202
Existing City CIP "SEW 52"
(Misc. Sewer Contract Main Upsize and Lift Station Facility Enlargements)
Growth & Development $234,182
Existing City CIP "SEW 55"
(Westside Interceptor - Three Mile Dr. and Spring Creek Project)
LS, Gravity & Force Main $13,612,312
Existing City CIP "SEW 68" (12" Clay Sewer Slipline in 1st Alley E. & W. Rehabilitation & Repair $232,565
Existing City CIP "SEW 70"
(Slipline 8" Sewer Main in 6th Alley EN and E. Washington)
Rehabilitation & Repair $79,675
Existing City CIP "SEW 72" (Lift Station Communication Upgrades) Optimization $40,400
Existing City CIP "SEW 74" (Grandview Lift Station #3 Relocation) Lift Station Upgrades $1,238,781
Existing City CIP "SEW 75" (Lift Station 5a Removal) Lift Station Upgrades $334,714
Existing City CIP "SEW 77" (Shop Complex Pavement Restoration) Rehabilitation & Repair $ 38,200
Existing City CIP "SEW 78" (Gravity Sewer Replacement on 4th Alley WN) Rehabilitation & Repair $1,064,754
Existing City CIP "SEW 79" (Gravity Sewer Replacement on 2nd Alley W) Rehabilitation & Repair $596,351
Existing City CIP "SEW 80" (Gravity Sewer Replacement on 5th Alley WN) Rehabilitation & Repair $817,968
Existing City CIP "SEW 82" (Gravity Sewer Replacement on 2nd Alley W.) Rehabilitation & Repair $809,281
Existing City CIP "SEW 83" (Gravity Sewer Replacement on 1st and 2nd Ave. EN) Rehabilitation & Repair $1,203,825
Existing City CIP "SEW 89" (Facility Plan/Rate Analysis) Studies $268,148
Existing City CIP "SEW 91" (Repair and Replacement of Sewer Main) Rehabilitation & Repair $600,000
Existing City CIP "SEW 92"
(Repair and Replacement of Sewer Main in WWTP Complex)
Rehabilitation & Repair $159,554
CIPs identifi ed within this WWFPU were divided into
short-term (0-5 year), near-term (5-15 year) and long-term
(15+) timeframes. Specifi c project timing was determined
using the hydraulic model, risk analysis, and anticipated system
growth maps developed by the City Planning Department.
Th rough the development of the WWFPU, three short-
term construction projects were identifi ed that were not
previously included in the City’s existing CIPs. Th e locations
of these projects are shown in the fi gure on the following page.
A summary including costs for the proposed short-term
CIPs identifi ed within this WWFPU, as well as the City’s
already identifi ed CIPs is included below.
CIP TIMING AND IMPLEMENTATION
Existing City CIP previously identifi ed by
City Staff as a short-term project.Total Opinion of Probable Cost $32,585,262
City of Kalispell WWFPU Executive Summary | Page 11
Projects identifi ed for the Capital Improvement Plan (CIP) were divided into eight categories briefl y summarized below.
Th e development of these categories provided the conceptual framework for CIP development, project prioritization and
timeframe progressions, and correlated projects to the City’s present fi scal resources (i.e. what type of project makes the best
use of the available capital improvement budget).
CAPITAL IMPROVEMENTS PLANNING
CONDITION ASSESSMENT
CCTV should be used to identify high-risk
degradation of a pipeline before failure, or
to verify that there is viable life remaining
in a segment of pipeline so that financial
resources are spent strategically on its
replacement or rehabilitation.
REHABILITATION & REPAIR
Rehabilitation and repair projects
are generally associated with pipe
segments that experience high break
rates, significant leakage, are undersized
(experience surcharging), or require
frequent maintenance.
GRAVITY MAIN
Consists of upgrading existing gravity main or
adding new future gravity main, which ensures
the City maintains its current level of service
and can adequately convey wastewater from
existing and future customers.
GROWTH & DEVELOPMENT
Provide the necessary infrastructure to
primarily serve future development.
These projects consist of lift stations,
gravity mains, and force mains.
LIFT STATIONS
Address both existing and future
wastewater needs through upgrades
or the addition of a new lift station.
FORCE MAIN
Consists of upgrading existing force main or
adding new future force main to adequately
convey wastewater away from lift stations to
other parts of the collection system.
OPTIMIZATION
Improve network efficiency and
movement or eliminate facilities to
reduce operating costs and improve
overall system performance.
STUDIES
Studies provide more detailed
information so that the City
can make informed decisions
regarding the cost and timing of
future projects.
City of Kalispell WWFPU Executive Summary | Page 4
:KLWHIL
V
K
5L
YHU
6WLOOZDWH
U
5L
Y
HU
$VKOH\&UHHN
)ODWKHDG 5 L Y H U
$
$
)R\V/DNH
2OG5HVHUYH'5
)D
U
P
W
R
0
D
U
N
H
W
5
'
:K
L
W
H
I
L
V
K
6
W
D
J
H
5
'
)XOO%XLOG2XW $QQH[DWLRQ%RXQGDU\
.DOLVSHOO&XUUHQW&LW\/LPLWV
(YHUJUHHQ6HUYLFH$UHD
<HDU*URZWK
<HDU*URZWK
*URZWK3ROLF\3ODQQLQJ$UHD *33$
H
SHORT-TERM GROWTH
25,200 People
Estimated Added Growth
+ 1,185 Residential Dwellings
+ 90 Commercial Acres
+ 28 Industrial Acres
LONG-TERM GROWTH
61,900 People
Estimated Added Growth
+ 15,023 Residential Dwellings
+ 633 Commercial Acres
+ 100 Industrial Acres
NEAR-TERM GROWTH
30,800 People
Estimated Added Growth
+ 2,875 Residential Dwellings
+ 331 Commercial Acres
+ 20 Industrial Acres
The City currently has
an agreement to treat
wastewater from the
neighboring community
of Evergreen, which was
included in this analysis.
City of Kalispell WWFPU Executive Summary | Page 5
Wastewater characterization involves analysis of existing wastewater fl ows to bett er understand the City’s wastewater
generation trends. Wastewater characterization is necessary to assess the capabilities of the City’s existing facilities as well
as ensure that the design and functionality of proposed wastewater system components satisfy future wastewater needs.
Wastewater fl ows were estimated by using the land use method along with anticipated future growth projections.
Wastewater Duty Factors (WWDFs) were generated and are expressed in terms of gpd / ERU for residential properties, and
gpd / acre for industrial and commercial properties. WWDFs were estimated based on an evaluation of historical water use
then reduced to refl ect observed wastewater fl ows at the City’s advanced wastewater treatment facility. Th e wastewater fl ows
were further evaluated and categorized by land use type as well as source category (i.e. Evergreen District, Sewer Only, and
City of Kalispell). Th e following WWDFs were used in this Facility Plan Update and the chart below represents the future
wastewater demands per planning period for each wastewater contributor.
0.0
1.5
3.0
4.5
6.0
7.5
9.0
2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017
Mi
l
l
i
o
n
G
a
l
l
o
n
s
p
e
r
D
a
y
(
M
G
D
)
Year
Existing Wastewater Flow Summary
Average Annual Flow (AAF)Maximum Monthly Flow (MMF)Maximum Daily Flow (MDF)
AAF 12-Year Historic Average MMF 12-Year Historic Average MDF 12-Year Historic Average
3.0 3.4
4.2
6.7
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
10.00
Existing 0-5 Year 5-15 Year FBO
Av
e
r
a
g
e
A
n
n
u
a
l
F
l
o
w
(
M
G
D
)
Future Wastewater Flow ProjectionsFuture Wastewater Flow Projections
Evergreen District City of Kalispell Sewer Only Customers
FUTURE WASTEWATER PROJECTIONS
HOW MUCH
WASTEWATER DO WE PRODUCE?
RESIDENTIAL
200 gpd / ERU
COMMERCIAL
500 gpd / acre
INDUSTRIAL
200 gpd / acre
PLANNING PERIOD
Th ese WWDFs represent the City of Kalispell and do not include the Evergreen District of Sewer Only Customers in the calculation.
(Total Flow at AWWTP)
7+67(
86
6811<6,'('5
681
6
(
7
3/=
7+67:
7
+
$
9
(
(
7
+
$
9
(
:
1
7+67:
5
'
$
9
(
(
1
1'67:
7+67(
1
'
$
9
(
(
1
7
+
$
9
(
(
1
:22'/$1'3$5.5'
.(1:$<
5'
7+67(
:&(17(567
6
7
$
9
(
:
7+67(
7
+
$
9
(
(
1
7+67(
1'67(
5'67(
7+67(
(1(9$'$
6
7
(&$/,)251
,
$
6
7
7+67:
7+67(
7
+
$
9
(
(
1
7
+
$
9
(
:
7+67(
:1(9$'$6
7
7
+
$
9
(
(
1
'(
19(
5
$9
(
6
7
$
9
(
:
1
1
'
$
9
(
:
1
7
+
$
9
(
:1
7
+$9((
:22
'
/$1'3$
5
.
'
55
'
$
9
(
:
1
),6+7$,/'5
1
'
$
9
(
:
7+67:
7
+
$
9
(
:
1
6767:
($5,=21$
6
7
7
+
$
9
(
:
0($'2:
&7
7+
$9(
:
7
+
$
9
(
(
1
7+67:
6
7
$
9
(
(
1
::<20,1*
6
7
7+$
9(:
:87$+67
6287+
)
,
(
/
'
/
1
:5$,/52$'
6
7
:&$/,)251
,
$
6
7
'(3273$5.
7+67(
7+67(
6767(
7+67:
7+67:
:0217$1$
6
7
5'67:
(&(17(567
::$6+,1*7
2
1
6
7
86
7+67:
:&2/25$'267
7+67:
(:$6+,1*
7
2
1
6
7
7+67(
6811<&7
(0217$1$
6
7
(:<20,1
*
6
7
(25(*216
7
10
$
,
1
6
7
3$5.+,//5'
:25(*216
7
6+$'<
*/(1'5
&2
/
/
(
*
(
$
9
(
&('$5
&200216
/
1
&5(67/
,
1
(
$9(
&215$''5
5
'
$
9
(
(
0,66,
2
1
67
:$5,=21$67
:2
2
'
/$
1'
$9
(
$,532575'
$6+/(<&5((
./1
7+67(
$6+/(<'5
7
+
$
9
(
:
1
.<1=,(/1
7
+
$
9
(
(
7
+
$
9
(
(
1
7
+
$
9
(
:
1
1
'
$
9
(
(
6
7
$
9
(
(
7
+
$
9
(
(
7
+
$
9
(
:
7
+
$
9
(
:
7
+
$
9
(
:
7
+
$
9
(
:
7
+
$
9
(
:
5
'
$
9
(
:
7
+
$
9
(
(
0$5.(7 3/$&(67
1 :22'/$1'3$5.5'
7$*(
7+67:
((1
:(
6
7
(
51'5
.(
1
:$<'5
:22'/$1
'
3$5./223
81'(5+,//&7
6
287+
),(/'
'5
%,
6
0
$
5
.
6
7
&+$5/
2
7
7
(
$
9
(
%,
5
&
+
:
2
2
'
&
7
(5$,/52$'67
6<
/
9
$
1
'
5
/$:5(1&(3$5.
6816(7
3/=
Z[
Z[
$VKOH\&UHHN
:DVWHZDWHU0DLQ7\SH
)RUFH0DLQ
*UDYLW\
([LVWLQJ:DVWHZDWHU6\VWHP
/LIW6WDWLRQ
7RWDO5LVN
/HYHO2QH
/HYHO7ZR
/HYHO7KUHH
/HYHO)RXU
/HYHO)LYH
Risk from each pipe segment was
determined by combining the
scores from the of likelihood and
consequence of failure assessments.
Th e majority of the City’s collection
system is in the lower risk range,
which corresponds to a level one or
two risk and thus, does not require any
current immediate action. Th e map
to the right presents a specifi c area of
water mains in the core downtown
area and their respective risk levels.
RISK ASSESSMENT
RESULTS
7
+
$
9
7 7
$9
77$$$$***(
(
..
Level 5: 0.1 miles
Level 4: 1.8 miles
Level 3: 3.9 miles
Level 2: 17.7 miles
Level 1 : 95 miles
Level 5: Catastrophic
Immediate Response Needed.
One small area was
identified as catastrophic,
which requires an
immediate response.
However, this area was
previously identified in
the City’s CIP for repair.
Level 4: Major
Sewer Main Video Inspection or
commonly referred as CCTV is
recommended to further evaluate
these mains to determine the
most cost effective mitigation
strategy.
Level 3: Moderate
These mains should be evaluated
after Level 4 mains have been
mitigated.
Level 2: Minor
No Current Action Required
Level 1: Insignifi cant
No Current Action Required
Sewer Main
Risk Breakdown
0.1%
1.8%3.9%
18.2%
76%
City of Kalispell WWFPU Executive Summary | Page 10
As the City continues to grow and provide wastewater service to additional customers, it is
important to make appropriate investments to keep the collection system maintained and
operating at a high-level. A risk assessment of the City’s collection system network was
completed to achieve the following:
Likelihood vs. Consequence of Failure
A risk assessment is comprised of assessing the likelihood of failure and consequence of failure. Th e risk assessment
completed for the City consisted of fi ve risk levels, ranging from “Insignifi cant Risk” to “Catastrophic Risk. ”
RISK ASSESSMENT
Develop a
Comprehensive
Understanding of
Collection System
Risk
Develop a
Prioritization of
Collection System
Improvements
Risk
Management &
Risk Mitigation
Informed &
Defendable
Decisions
Smart Investments
for Appropriate
Infrastructure
Assessment,
Replacement, and
Maintenance
F Major Major Catastrophic Catastrophic Catastrophic
D Moderate Moderate Major Catastrophic Catastrophic
C Insignificant Minor Moderate Major Major
B Insignificant Insignificant Minor Moderate Major
A Insignificant Insignificant Insignificant Minor Moderate
1 2 3 4 5
Li
k
e
l
i
h
o
o
d
Consequence
VSLIKELIHOOD ASSESSMENT
Th e process of “screening” each individual pipeline segment
through the likelihood of failure components. Th is process
provides a bett er understanding of how susceptible the
pipeline segment is to failure. Factors identifi ed and used in
the Likelihood Assessment include:
CONSEQUENCE ASSESSMENT
Th e process of “screening” each pipeline segment through the various
consequence of failure components. Th is process provides a bett er
understanding of how critical the pipeline segment is to the collection
system, as well as the over-arching consequence that could burden the
collection system in the event of a failure. Factors identifi ed and used
in the consequence assessment include:Physical Condition
Recorded Structural
Defects
Performance
Hydraulic Capacity from
Model Results
Age
Pipe Age and Material
Maintainability
Access to Pipe for
Maintenance Purposes
Reliability History
City Work Orders Indicating
a History of Pipe Issues
Health & Safety Impact
Medical and School
Proximity to Manholes
Direct Financial Impact
Depth of the Wastewater
Pipe
Public Image &
Confidence
Type of Zone and Road Type
Environmental Impact
Water Body Proximity to
Manholes
WHAT IS RISK?
NOTE: Collection system risk will
be routinely reevaluated which will
help City staff prioritize changes as
new information is collected.
City of Kalispell WWFPU Executive Summary | Page 9
Identifies sewer mains that pose a high risk of failure/should be further
investigated to determine the most cost-effective mitigation strategy.
City of Kalispell WWFPU Executive Summary | Page 6
0
50,000
100,000
150,000
200,000
250,000
300,000
350,000
400,000
450,000
8:
0
0
A
M
6:
0
0
P
M
4:
0
0
A
M
2:
0
0
P
M
12
:
0
0
A
M
10
:
0
0
A
M
8:
0
0
P
M
6:
0
0
A
M
4:
0
0
P
M
2:
0
0
A
M
12
:
0
0
P
M
10
:
0
0
P
M
8:
0
0
A
M
6:
0
0
P
M
4:
0
0
A
M
2:
0
0
P
M
12
:
0
0
A
M
10
:
0
0
A
M
8:
0
0
P
M
6:
0
0
A
M
4:
0
0
P
M
2:
0
0
A
M
12
:
0
0
P
M
10
:
0
0
P
M
Ga
l
l
o
n
s
p
e
r
H
o
u
r
(
g
p
h
)
Time
Wet Weather (March Sample) Diurnal Pattern
Monday 3/13/17
Tuesday 3/14/17
Wednesday 3/15/17
Thursday 3/16/17
Friday 3/17/17
Saturday 3/18/17
Sunday 3/19/17
Monday 3/20/17
Tuesday 3/21/17
Flow varies due to
wet weather events.
Wastewater systems commonly experience higher wastewater fl ows during spring and summer months. Th is is typically
att ributed to wet weather events such as snow melt and rainfall, as well as increased water demands. I/I is a critical
consideration when evaluating collection system capacity. With the presence of groundwater, infi ltration can infl uence
the system during dry weather. System fl ows will also increase during and aft er rain events due to rainfall derived I/I.
8.58 9.27 9.95 9.74
8.46 8.63 8.29 7.47 6.85 6.75
3.00 3.00 3.00 3.00 3.00 3.00 3.00 3.00 3.00 3.00
2.9 3.1 3.3 3.2
2.8 2.9 2.8 2.5 2.3 2.3
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
Monday
3/13/17
Tuesday
3/14/17
Wednesday
3/15/17
Thursday
3/16/17
Friday
3/17/17
Saturday
3/18/17
Sunday
3/19/17
Monday
3/20/17
Tuesday
3/21/17
Wednesday
3/22/17
Pe
a
k
i
n
g
F
a
c
t
o
r
Fl
o
w
(
M
G
D
)
Wet Weather Flow Period
PHF (mgd)2017 AAF (mgd)Peaking Factor
Wet Weather (March 2017 Sample) Diurnal Pattern
Wet Weather Flow Period (March 13-22, 2017)
SEASONAL VARIATIONS
• Lift Station Capacities
• Force Main Capacities
• Gravity Main Capacities
• I&I Identification
• Criticality Assessment
Valuable Tool to Quickly Diagnose
System Challenges and Plan for Growth
MODEL DEVELOPMENT AND CALIBRATION
Creating a model that accurately simulates wastewater fl ows
throughout the collection system is useful to help identify I&I as well
as other system defi ciencies. Wastewater was spatially allocated in
the model to accurately simulate fl ows generated across the system.
Real fl ow data was utilized for calibration to ensure the model
accurately represents existing conditions.
“All Pipe” Models Provide Accurate Simulation
The new hydraulic models are “all pipes” models, meaning that
they maintain a one-to-one relationship between individual
elements in the City’s GIS database and pipes in the model.
An all pipes model results in a more accurate simulation, and
enables continuous model updates and maintenance with
changes in the City’s GIS database (that reflect changes in its
infrastructure). This is critical for a City growing as fast as
Kalispell and to avoid the model becoming outdated.
The City now has a valuable tool that can be utilized
with a high degree of confidence and accuracy.
MODEL UPDATE & CALIBRATION
Th e development of an accurately calibrated model provides the City with the ability to analyze
countless scenarios and answer the looming “What If” questions as the City grows and expands.
City of Kalispell WWFPU Executive Summary | Page 7
Ͳ
ϮϬ
ϰϬ
ϲϬ
ϴϬ
ϭϬϬ
ϭϮϬ
Hydraulic Model Flow Comparison at Sanitary Lift Station #2
September 8th through the 17th, 2017
WA
S
T
E
W
A
T
E
R
F
L
O
W
(
G
P
M
)
OBSERVED
SIMULATED
City of Kalispell WWFPU Executive Summary | Page 8
SYSTEM EVALUATION
Th e wastewater collection system was evaluated under existing and future wastewater fl ow conditions. Th e
calibrated model was used to determine potential areas of I/I and identify defi ciencies particularly during periods
of wet weather. Peaking factors developed from the analysis were used to evaluate and size both existing and future
sanitary sewer pipe. An understanding of the limitations of the existing wastewater collection system is critical to
the development and expansion of the system for satisfactory system performance, longevity, and to accommodate
future growth. Th e system evaluation included review of the following components:
FORCE MAIN CAPACITY – Identifies force mains that exceed recommended velocity and head loss criteria.
GRAVITY MAIN CAPACITY – Identifies gravity mains that exceed recommended hydraulic capacity or have
slopes or velocities that do not satisfy recommended standards.
LIFT STATION CAPACITY – Identifies lift stations that are projected to experience flows that exceed their
current pumping capacities.
EL
E
V
A
T
I
O
N
(
F
T
)
DISTANCE
Sanitary Sewer Main Upstream of Lift Station #9
WATER LEVEL
GROUND LEVEL
Modeled Wastewater Flows show upstream
capacity issues. Recommendations included
upsizing existing pipe as well as increasing lift
station capacity to meet future wastewater flows.
Short-term force main recommendations include adding a new force main from Lift Station
#3 along Four Mile Drive to the newly constructed Westside Interceptor, which helps alleviate
future downstream capacity issues while maximizing existing gravity main capacity.
A majority of the existing gravity main has excellent cacpacity.
Short-term recommendations included upsizing specific sections of gravity main to
accommodate future wastewater flows
Short-term recommendations include modifications to both Lift Station #3 and #9 to handle
projected future wastewater flows. A hydraulic profile of Lift Station #9 is shown below.