Stormwater Facility Master Plan
City of Kalispell
Storm Water Facility Plan Update
March 28, 2008
Prepared by
HDR Engineering, Inc. Morrison Maierle, Inc.
1715 South Reserve Street, Suite C 1228 Whitefish Stage Road
Missoula, MT 59801 Kalispell, MT 59901
List of Preparers: Acknowledgements:
Mark Franchi, P.E.
Ken Salo, P.E.
Terry Richmond, P.E.
Craig Caprara, P.E.
Zane Green, E.I.
Jason Larsen
Marty Binde
Cil Pierce
Judy Dean
The successful completion of this
document was made possible through
the cooperation and assistance of the
following City of Kalispell Public
Works Staff.
Jim Hansz, Public Works Director
Frank Castles, City Engineer
Paul Burnham, Assistant City Engineer
Susie Turner, Associate Civil Engineer
Terry Loudermilk, Finance
Tom Jentz, Planner
Contents
Table of Contents
1.0 EXECUTIVE SUMMARY................................................................................................................1-1
1.1 Introduction...................................................................................................................................1-1
1.2 Basis of Planning ..........................................................................................................................1-1
1.3 Regulations ...................................................................................................................................1-1
1.4 Storm Water Major Conveyance, Detention and Discharge Analysis..........................................1-2
1.5 Recommendations and Capital Improvements Plan .....................................................................1-2
1.6 Financial Plan ...............................................................................................................................1-2
2.0 BASIS OF PLANNING ....................................................................................................................2-3
2.1 Study Area ....................................................................................................................................2-3
2.1.1 Introduction...................................................................................................................................2-3
2.1.2 Study Area Boundary Development .............................................................................................2-3
2.1.3 Study Area Description.................................................................................................................2-4
2.1.4 Land Use (Existing Conditions)....................................................................................................2-4
2.2 Population and Growth .................................................................................................................2-7
2.2.1 Existing Population and Current Trends.......................................................................................2-7
2.2.2 Future Population Forecast ...........................................................................................................2-8
2.2.3 Comparison to Other Planning Studies....................................................................................... 2-12
2.2.4 Recommended Future Population Projections ............................................................................ 2-13
2.2.5 Land Use (Post-Development).................................................................................................... 2-14
2.3 Storm Water Management and Design Standards......................................................................2-16
2.3.1 Introduction................................................................................................................................. 2-16
2.3.2 Water Quantity (Runoff Control)................................................................................................ 2-17
2.3.2.1 Regional Detention Ponds....................................................................................................... 2-17
2.3.2.2 Closed Basins.......................................................................................................................... 2-17
2.3.2.3 Storm Water Management Ponds............................................................................................ 2-17
2.3.2.4 Existing Natural Drainage Ways............................................................................................. 2-17
2.3.3 Best Management Practices ........................................................................................................ 2-18
2.3.4 Management and Policy Recommendations ............................................................................... 2-18
3.0 REGULATIONS..............................................................................................................................3-1
3.1 Introduction...................................................................................................................................3-1
3.2 Local Regulations .........................................................................................................................3-1
3.3 State Regulations ..........................................................................................................................3-1
3.4 MS4 Phase II Permitting...............................................................................................................3-2
4.0 STORM WATER MAJOR CONVEYANCE, DETENTION AND DISCHARGE ANALYSIS .................4-1
4.1 Introduction...................................................................................................................................4-1
4.2 System Analysis Methodology .....................................................................................................4-1
4.2.1 Drainage Area ...............................................................................................................................4-1
4.2.2 Curve Number (CN)......................................................................................................................4-2
4.2.3 Time of Concentration (Tc) ..........................................................................................................4-4
4.3 Precipitation – Rainfall Runoff Estimation...................................................................................4-5
4.3.1 Hydrology.....................................................................................................................................4-5
4.3.2 Recurrence Interval for Design of Regional Facilities..................................................................4-6
March 28, 2008 City of Kalispell Storm Water Facility Plan Update i
Contents
4.4 Storm Water Major Conveyances, Detention and Discharge Analysis ........................................4-7
4.4.1 Storm Water Study Area...............................................................................................................4-7
4.4.2 Storm Water Major Conveyance, Detention and Discharge System Analysis..............................4-7
4.4.2a East Whitefish River Study Area .............................................................................................4-7
4.4.2b North Kalispell Study Area .................................................................................................... 4-11
4.4.2c West Stillwater Study Area .................................................................................................... 4-16
4.4.2d West Kalispell Study Area ..................................................................................................... 4-21
4.4.2e East Kalispell Study Area....................................................................................................... 4-26
4.4.2f South Kalispell Study Area........................................................................................................ 4-28
5.0 RECOMMENDATIONS AND CAPITAL IMPROVEMENTS PLAN ....................................................5-1
5.1 Introduction...................................................................................................................................5-1
5.2 Capital Improvement Program Prioritization................................................................................5-1
5.3 Capital Improvement Recommendations......................................................................................5-2
5.3.1 Regional Detention Ponds (DP) Facilities:...................................................................................5-2
5.3.2 Detention Pond (DP) and Storm Water Management Pond (SWMP) Facility Design
Guidelines:....................................................................................................................................5-3
5.3.3 Regional Facility Volume Management:......................................................................................5-4
5.3.4 Closed Basin (CB) Facilities:........................................................................................................5-5
5.3.5 Conveyance Outlet Pipelines (COP) Facilities .............................................................................5-6
5.3.6 Growth versus Renewal and Replacement Costs..........................................................................5-7
6.0 FINANCIAL PLAN .........................................................................................................................6-1
6.1 Introduction...................................................................................................................................6-1
6.2 Overview of the Financial Planning Process ................................................................................6-1
6.3 Past Financial History...................................................................................................................6-3
6.4 Development of the Financial Plan...............................................................................................6-3
6.5 Potential Funding/Financing Sources ...........................................................................................6-7
6.6 Summary of the Financial Projections ........................................................................................6-11
6.7 Rate Impacts ...............................................................................................................................6-13
6.8 Review of the City’s Storm Water Rates ....................................................................................6-14
6.9 Summary of Storm Water Financial Plan ...................................................................................6-15
APPENDIX A - Regulatory Storm Water Permits
APPENDIX B - TR-20 Existing Input and Output Run Data
APPENDIX C - TR-20 Post-Developed Input and Output Run Data
APPENDIX D - Probable Cost Estimates
ii City of Kalispell Storm Water Facility Plan Update March 28, 2008
1.0 Executive Summary
1.0 Executive Summary
The following report is an update to the 2002 City of Kalispell Water, Sewer and Storm
Drainage Systems Facility Plan. The purpose of this report is to expand the area covered
by the 2002 Facility Plan to the potential growth area for the next 40 to 50 years
(planning year 2050). The 2002 Water, Sewer and Storm Drainage Systems Facility Plan
covered the service area bounded by the Flathead River to the east, Rose Crossings to the
north, West Spring Creek Rd. to the west and Ashley Meadows to the south. The study
area for this facility plan encompasses additional areas north, west and south of that
boundary as shown on Figure 2-4.
1.1 Introduction
The Storm Water update to the 2002 City of Kalispell Water, Sewer and Storm Drainage
Systems Facility Plan analyzed surface water for the study area shown in Figure 2-4.
Storm water planning for the study area was divided into six sub-areas including: a) East
Whitefish River, b) North Kalispell, c) West Stillwater River, d) West Kalispell, e) East
Kalispell and f) South Kalispell as shown on Figure 4.2-1. The study provides
quantitative goals and standards for managing surface water runoff in the study area.
Design data for 60 drainage basins included basin delineations, drainage areas, and
existing natural drainage ways. The quantitative analysis provides approximate pond
storage volumes, allowable peak discharge flow rates, and potential regional pond
locations.
1.2 Basis of Planning
The City of Kalispell is updating the facility plan for its storm water infrastructure.
Determination of the existing and post-developed characterization and runoff estimation
is dependent on topography, soils, land use, population density, the magnitude and type
of commercial and industrial activity in the area. This section describes the basis of
planning, which includes background information on existing population, future
population estimating, other planning documents, physical characteristics of the study
area, and other parameters that influence the storm water infrastructure.
1.3 Regulations
This section of the Facility Plan summarizes the local, state and federal, and Phase II
storm water regulations and permits that the City of Kalispell has implemented or plans
to implement.
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 1-1
1.0 Executive Summary
1.4 Storm Water Major Conveyance, Detention and Discharge
Analysis
This section of the Facility Plan summarizes the results and findings of the quantitative
evaluation of the existing and post-development storm drainage analysis for the study
area. The study area includes areas outside of the existing City Limits that are likely to
be developed and annexed to the City in the future. The storm drainage evaluation
utilized aerial and land use mapping developed by the City of Kalispell to define and
characterize drainage basins and provide existing and post developed characterization and
runoff estimation. The USDA Small Watershed Hydrology computer model TR-20 was
used to provide the hydrologic analyses of each drainage basin watershed under existing
and post-development conditions.
1.5 Recommendations and Capital Improvements Plan
This section of the Facility Plan summarizes the Capital Improvements recommended in
the City of Kalispell 2007 Storm Water Facility Plan Update. This includes the program
prioritization and design guidelines for the regional detention ponds, closed basins, and
conveyance outlet pipelines storm water facilities.
1.6 Financial Plan
The effective implementation of a comprehensive storm water plan is dependent upon
developing a financial plan which can be supported by the utility, will meet State and
local regulatory requirements, and provides the flexibility to deal with unforeseen
changes. The financial status if the City of Kalispell’s storm water utility was evaluated
using a “cash basis” approach. A five-year financial plan was developed to demonstrate
the City’s ability to meet its operating and capital improvement needs and evaluate
potential rate adjustments that may be necessary to meet those needs. This work effort
was not intended to be a comprehensive rate analysis since it does not address the typical
rate study issues of cost of service and rate design. The City plans to conduct a
comprehensive rate study in the future, which will provide a more detailed rate analysis
to support any needed rate adjustments to implement the comprehensive storm water
plan.
The financial evaluation indicates that storm water rates for the five-year projected time
horizon of FY 2009 to FY 2013 will be deficient in meeting the projected O&M, capital,
and debt service requirements. Continued analysis and monitoring of capital funding and
financing and performing a comprehensive rate analysis will provide the City with the
information necessary to determine future rate adjustments.
1-2 City of Kalispell Storm Water Facility Plan Update March 28, 2008
2.0 Basis of Planning
2.0 Basis of Planning
In 2006, the City of Kalispell undertook the task of updating the facility plan for its storm
water infrastructure. Determination of the existing and post-developed characterization
and runoff estimation is dependent on topography, soils, land use, population density, the
magnitude and type of commercial and industrial activity in the area. This section
describes the basis of planning, which includes background information on existing
population, future population estimating, other planning documents, physical
characteristics of the study area, and other parameters that influence the storm water
infrastructure.
2.1 Study Area
The study area boundary encompasses the general area for which this facility plan
investigates in detail; and the study area boundary is synonymous with the planning area,
and future build-out area.
2.1.1 Introduction
Storm water runoff for the existing and post-developed study area is dependent, in part,
by the size and the land use of the study area. The physical characteristics of the area,
such as topography, soils, and geographical location, greatly influence the type of land
use and in turn the population density as well as commercial and industrial activity within
the area. The planning investigation examines the physical characteristics of the study
area, population densities, and land use that dictate storm water infrastructure
requirements in the future.
2.1.2 Study Area Boundary Development
For this facility plan, the City of Kalispell chose to analyze potential growth for the next
40 to 50 years, which the project team selected as the planning year 2050. This time
frame was chosen because it allowed reasonable projection of growth trends, and it
coincides with the life-cycle of storm water infrastructure. To determine the study area,
several meetings were held with staff from the City of Kalispell Public Works and
Planning Departments. The 2002 Water, Sewer and Storm Drainage Systems Facility
Plan developed a potential future utility service area bounded by the Flathead River to
the east, Rose Crossings to the north, West Springcreek Rd. to the west and Ashley
Meadows to the south. The study area for this facility plan encompasses additional areas
north, west and south of that boundary shown in Figure 2-4 located at the end of this
chapter.
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 2-3
2.0 Basis of Planning
2.1.3 Study Area Description
The area studied in this document is bounded by the Flathead River on the east, includes
Glacier Park International airport to the north, and is bounded by Lost Creek Drive to the
north, Farm to Market Road on the west, and Buckboard Lane and Valley View Drive on
the southwest. The study area boundary continues in the southeasterly direction until
reaching Highway 82 which is the southern boundary of the study area, then proceeds
north and west until reaching the Flathead River which is the eastern boundary of the
study area as shown in Figure 2-4 at the end of this chapter.
This Study Area Boundary extends beyond the current Kalispell City limits and does not
represent future city limits. It represents the area studied for this report, and the potential
area that is likely to experience significant growth in the next 50 years.
2.1.4 Land Use (Existing Conditions)
Important physical characteristics for this facility plan update include surface water,
wildlife habitat, steep slopes, soil limitations, floodplains, parks and recreational lands,
and important agricultural lands. This section provides a brief overview of these
characteristics, some of which are also shown on Figure 2-5 Physical Characteristics,
located at the end of this chapter. Much of this information is presented in greater detail
in the City of Kalispell Growth Policy.
Introduction. Kalispell is located at the center of the Upper Flathead Valley, a
broad agricultural valley generally surrounded by the foothills and mountains of
the Flathead National Forest, Stillwater State Forest and Glacier National Park.
The Swan Range to the east rises 4,500
feet above the valley floor and peaks
further east along the continental divide
reach elevations above 10,000 feet. The
elevation of Kalispell is 2,959 feet.
The topography and geography of the
study area presents certain development
constraints due to hydric soils, steep
slopes, floodplain and other limitations.
Most of the study area consists of nearly
level alluvial lands, bottom lands and low terraces. The Flathead, Whitefish, and
Stillwater Rivers in the eastern half of the study area are part of a large riparian
complex which creates a large floodplain area.
The Flathead River just downstream from Kalispell, MT.
2-4 City of Kalispell Storm Water Facility Plan Update March 28, 2008
2.0 Basis of Planning
Surface Water. Significant surface water in the study area includes the Flathead
River, Ashley Creek, Spring Creek, the Stillwater River, and the Whitefish River.
The Flathead River starts in southeast British
Columbia, Canada, and flows south through
northwest Montana to Flathead Lake before
draining into the Clark Fork River. Its three
forks, the North Fork, Middle Fork, and South
Fork are designated National Wild and Scenic
Rivers. The Flathead River drains into
Flathead Lake approximately ten miles
southeast of Kalispell.
Ashley Creek flows from the Smith Valley
into the greater Flathead Valley toward the
City of Kalispell, then to the mainstem of the
Flathead River about 15 miles upstream from
Flathead Lake. The watershed is characterized
by heavily timbered mountains in the
headwaters and a mixture of farmland and residential dwellings at lower
elevations near steams. Given the watershed's proximity to Kalispell, the region's
largest city, it is becoming increasingly urbanized. Ashley Creek from Airport
Road to Smith Lake is on the Montana Department of Environmental Quality’s
(MDEQ) 303(d) list. Spring Creek is a perennial tributary to Ashley Creek.
The Stillwater River rises 15 miles south of the border between Montana and
Alberta, Canada, west of Glacier National Park in the Kootenai National Forest.
It runs mainly south to Duck Lake, then Upper Stillwater Lake, Lagoni Lake and
on to Lower Stillwater Lake. It then flows south to Kalispell where it joins the
Whitefish River, very near the confluence of that river with the Flathead River.
The Whitefish River flows southerly from Whitefish Lake to join the Stillwater
River near U.S. Highway 2 east of Kalispell. The river then flows a short
distance to Flathead Lake. The Whitefish River, the Stillwater River, and
Flathead Lake are 303(d) listed bodies of water1.
Wildlife and Important Habitat. The study area supports a variety of wildlife
species. Typical riparian/wetland species associated primarily with the Flathead-
Stillwater complex include: large mammals such as white-tailed deer, mountain
lions, an occasional black bear or moose; small mammals such as beaver, river
Ashley Creek
1 DEQ is required to develop Total Maximum Daily Loads (TMDL) for all water bodies on the 303(d) list. A
TMDL is the total amount of a pollutant that a water body may receive from all sources without exceeding
water quality standards. A TMDL can also be defined as a reduction in pollutant loading that results in
meeting water quality standards.
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 2-5
2.0 Basis of Planning
otter, mink, muskrat, raccoons; resident or migrant water birds such as great blue
herons, tundra swans, killdeer, spotted sandpipers; nesting and migratory
waterfowl such as wood ducks, mallards, common mergansers, common golden
eyes, Canada geese; woodland bird species such as pileated woodpeckers, great-
horned owls, saw whet owls, osprey, bald eagles, a variety of migratory and
resident songbirds, rubber boas, garter snakes, painted turtles, long-toed
salamanders, spotted frogs, and western toads.
The Flathead River mainstem, Stillwater River, Whitefish River, Ashley Creek
and Foy Lake(s) and their associated backwater channels, spring creeks, wetlands
and tributaries provide very important wildlife habitats. The riparian and wetland
habitats along these major waterways, particularly those which still support intact
natural stands of forest and shrubby vegetation or marshes, are critical to
retaining a variety of wildlife within the study area.
Parks and Recreational Lands. The
Kalispell Growth Policy defines several
different types of parks, and described
them as part of a larger open space
system. Table 2-1 provides an inventory
of the City, County and State parks in
the growth policy area, along with their
size.
Table 2-1: City Parks
City Park Acres
Woodland Park 38.5
Lawrence Park 56.0
Courthouse Park 1.26
Depot Park 2.5
Gallagher Park 2.0
Greenbriar Park 1.45
Hawthorne Park 2.39
Lions Park 10.0
Meridian Park 3.3
Northridge 7.15
Parkview Terrace 0.3
Sunset Park 4.55
Thompson Field 2.0
Washington Street Park 1.0
Buffalo Head Park 0.8
Dry Bridge Park 25.0
Begg Park 8.21
Laker and Archie Roe 4.27
Eagle Park 0.25
Heritage Park 2.0
Grandview Drive Park 4.49
Tennis Court Complex 0.2
Central School 0.25
Helen O’Neil 0.25
Youth Athletic Field 134
Total Acres 312.12
Woodland Park, Kalispell
2-6 City of Kalispell Storm Water Facility Plan Update March 28, 2008
2.0 Basis of Planning
City Park Acres
Source: City of Kalispell Growth Policy,
Appendix A, 2003.
2.2 Population and Growth
The main factors effecting storm water runoff are population, density, and growth trends.
Several sources of information were used to establish current population, and potential
population growth trends. These sources include the 2000 U.S. Census, City of Kalispell
Planning Department reports, developer interest and plats recently filed with Flathead
County, septic system and building permits, and growth trends since the last facility plan
(2002). Figure 2-6 Population, located at the end of this chapter, shows the existing
population (2005), future population (2025), and the theoretical build out population
(2050).
2.2.1 Existing Population and Current Trends
The population of Kalispell, the surrounding area, and much of Flathead County has been
steadily growing over the past several decades. To determine the current population, the
planning area boundary was examined in conjunction with the census block group data
from the 2000 Census. The census block group data within the planning area boundary
was extracted, and the 2000 U.S. Census reports that there are 32,044 people within the
planning area boundary.
Population Growth between 2000 and 2005.
Between 2000 and 2005, 3,388 lots were platted
within the study area boundary, according to
Flathead County subdivision information. Of
these lots platted, there are almost no vacancies within Kalispell City limits
(according to the Kalispell Planning Department), so all of these lots were
considered occupied. However, there is a high vacancy rate within the County, so
to determine which plats were occupied and which ones were not, water well and
septic system permits were identified. If a lot has been platted and had a
development related permit, it was considered occupied. Of the 3,388 lots
platted, 2,895 are within the study area boundary and considered occupied for
planning purposes. In addition, the City of Kalispell Residential Construction,
Land Subdivision, and Annexation Report, January 2006 states that 2,644 new
lots were created between 2000 and 2005. This 251 lot difference is likely
because all subdivisions within the planning area boundary were not approved by
the City of Kalispell, but were approved by Flathead County.
In 2005, there were an
estimated 39,282 people living
within the defined study area
boundary.
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 2-7
2.0 Basis of Planning
According to the Kalispell planning office there are an estimated 2.5 persons per
household2 in new residential development in the Kalispell area. Therefore,
between 2000 and 2005 the population within the planning area boundary
increased by 7,237 people3 (approximately 4.2% per year), for a total existing
population of 39,282 within the study area boundary. Table 2-2 summarizes
population growth data for the State of Montana, Flathead County, and the City
of Kalispell.
Table 2.2-1: Population Summary
Montana
1960 1970 1980 1990 2000 2005
Total Population 674,767 694,409 786,690 799,065 902,195 935,670
Change 19,642 92,281 12,375 103,130 33,475
Percent Change 2.9% 13.29% 1.57% 12.91% 3.71%
Flathead County, Montana
1960 1970 1980 1990 2000 2005
Total Population 32,965 39,460 51,966 59,218 74,471 83,480
Change 6,495 12,506 7,252 15,253 9,009
Percent Change 19.7% 31.7% 14.0% 25.8% 11.7%
City of Kalispell, Montana
1960 1970 1980 1990 2000 2005
Total Population 10,151 10,526 10,648 11,917 14,223 18,480
Change 375 122 1,269 2,306 4,257
Percent Change 3.6% 1.1% 10.6% 16.2% 29.9%
Source: Annual Estimates of the Population for Incorporated Places in Montana, by County: April 1, 2000 to
July 1, 2005
Sources: Table 16, 1990 CPH-2-1; Table 25, 1990 CPH-2-1; and Table 13, 1980 PC80-1-1
2.2.2 Future Population Forecast
Reasonable future population projections are important in the analysis of future storm
water infrastructure needs and the impacts to City infrastructure. Several analysis
methods were used to project future population, and these were compared and contrasted
with available planning documents. No method is exact and all have limited reliability
and must be tempered by knowledge of the area, its industry, employment potential,
economic conditions, trade area, and state of development. This section describes that
process and provides recommended future population projections.
Introduction. The population trend shows increasing growth percentages for the
City of Kalispell. For this facility planning effort, population estimates are made
through year 2050.
2 According to the U.S. Census, there are 2.2 persons per household, on average. However, after
discussions with City of Kalispell planning and public works staff, it was determined that the average
household size in the City of Kalispell is closer to 2.5 persons per household.
3 2,895 lots multiplied by 2.5 persons per household is equal to 7,237.5 people.
2-8 City of Kalispell Storm Water Facility Plan Update March 28, 2008
2.0 Basis of Planning
Meetings. During meetings with the City of Kalispell Planning and Public
Works Departments, housing densities and population estimates were made for
areas within the planning boundary. These estimates were based on existing
density, types of development, land use, and zoning. According to these
estimates, the ‘theoretical build-out’ would include 70,177 new units or 154,386
people within the study area boundary and generally outside of the City limits.
Similarly, theoretical build out within the current Kalispell City limits would
include the lots currently platted, land in Section 36, and about 1,000 other
anticipated connections. This totals 4,217 units and about 10,543 additional
people for a total of 29,614 people within current city limits. In 2005, there were
an estimated 8,200 people in the Evergreen Water District. If the Evergreen
Water and Sewer District population grows to the approximate maximum
possible, based on the current interlocal agreement with the City of Kalispell and
per capital flow and loading calculated for Evergreen, the population would be
10,164, thus adding approximately 1,964 people to the existing 8,200 people.
Therefore, according to the information gathered during agency meetings, the
maximum theoretical build out population is estimated at about 194,164 people
within the study area, as shown in Table 2.2-2.
Table 2-3: Theoretical Build Out Population
Theoretical Build Out Population
City of Kalispell 29,614
Evergreen 10,164
Study Area (outside Evergreen and
City of Kalispell)
154,386
Total 194,164
The theoretical build out would occur if all available land was built upon
according to likely densities. The theoretical build out does not consider political
or ownership limitations that may exist or be placed on properties in the subject
area; therefore, estimated future population should not exceed this theoretical
build out.
Demographic and Population Growth Theories. Data over the last 5 to 10 years
shows significant growth in Kalispell, and all of western Montana. However, it
should be noted that there are theories predicting slowed population growth after
2030 or so due to demographic trends including the ‘baby boomer’ generation.
The ‘baby boomer’ generation is considered those 70-80 million Americans born
between 1946 and 1964, and are currently starting to retire or enter second
careers. Places like Kalispell, with a high quality of life and generally low cost of
living appear to be favorable locations for this generation. The following figure
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 2-9
2.0 Basis of Planning
shows a 228% increase in the population of people aged 65 and older in Flathead
County between 2000 and 2030; compared with the total population increasing
by 71% (according to the State of Montana Census and Economic Information
Center http://ceic.mt.gov/PopProjections.asp). This large flux in population may
be followed by a slowing of population growth as the ‘baby boomer’ generation
passes on.
Figure 2-1 Montana Population Projections for 2030
Regression Analysis. Regression analysis was performed using the historical
Kalispell population growth data (1960 through 2000). Various regression lines
were drawn, including linear, exponential, power, and logarithmic4. R2 values
4 Linear regression involves fitting a straight line into a data set to determine future outcomes (i.e. y = mx
+ b). Exponential regression is fitting a line to a set of data where the growth is proportional to its size.
Power growth attempts to fit a line to a set of data that is closely tied to a power function (i.e. y = mx2). Logarithmic is a mathematical term for the ratio of values expressed by the base 10 or e. If the base is 10,
the logarithm is called common. If the base is e, the logarithm is called natural.
2-10 City of Kalispell Storm Water Facility Plan Update March 28, 2008
2.0 Basis of Planning
were calculated for each of those regression lines to determine which line
corresponded best to the data, or which type of regression line formed the ‘best
fit’ for historic growth data. The exponential growth line had the highest R2 value
at 0.855. This type of regression lines was applied to the percentage growth
analysis described below.
Percentage Growth per Year. Another future population estimate was made by
assigning percentage growth rates per year to the existing population.
Table 2.2-3 shows Kalispell Planning Area population estimates for 1.3%, 2%,
3%, and 4% per year; these are also represented on Figure 2-6 Population Growth
in the Study Area by Percentage Estimates. (1.3% was included because this is
the estimated growth rate presented in the Kalispell Growth Policy.) Regression
lines, or ‘best fit’ lines, were drawn for each percent growth. According to data
from 1960 through 2005, 1.3% growth was the ‘best fit’; however, the 4%
growth rate was the best fit for growth from 2000 to 2005.
Table 2.2-3: Population Growth by Percentage within the Study Area
Boundary
Year
1.3% growth
per year
2% growth
per year
3% growth
per year
4% growth
per year
2005 39282 39282 39282 39282
2010 41903 43371 45539 47793
2020 47680 52868 61200 70745
2025 50861 58371 70948 86072
2030 54254 64446 82248 104719
2035 57873 71154 95348 127407
2040 61734 78560 110534 155010
2050 70246 95764 148549 229453
Note: As stated above, these numbers do not include the Evergreen Water District.
5 R2 denotes the fraction of the total squared error that is explained by the model. Thus values
approaching one are desirable, and represent a “goodness of fit.”
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 2-11
2.0 Basis of Planning
0
50000
100000
150000
200000
250000
2010 2020 2030 2040 2050
Year
Po
p
u
l
a
t
i
o
n
1.30%
2%
3%
4%
Figure 2-2 Population Growth in the Study Area by Percentage Estimates
2.2.3 Comparison to Other Planning Studies
Kalispell Growth Policy 2003. The City’s growth policy is a planning document
that is comprehensive, general, and long-range and provides guidance for land
use, growth and development, subdivisions, and environmental policy. The
growth policy identified Kalispell as a ‘growth area’, and includes the following
statement, “the average annual growth rate of the growth policy area population
was 1.7 percent in the 1960’s, 3.7 percent in the 1970’s, 1.8 percent in the
1980’s, and 1.6 percent per year from 1990 to 2000.” The growth policy
discusses population projections stating that the “four percent annual growth rate
of the growth policy area in the early
1990’s has declined, indicating the
continuation of a cyclical growth
pattern. Population growth over the next
20 years is projected to slow to an
average annual rate of 1.3 percent by the
year 2020, based on arithmetic
regression analysis of population
changes since 1960. Based on these assumptions, the population of Kalispell can
be anticipated to increase approximately 27.8 percent over the next 20 years.
Unforeseen future events, economic cycles, and large-scale annexations can
create wide variations in these numbers.”
Flathead County Growth Plan estimates
111,740 people in the County by 2005, or
1.5% per year. However, since 1960 the
County has grown 2.1% per year on
average. If this rate continues, there will
be 127,270 people in the County by 2025.
2-12 City of Kalispell Storm Water Facility Plan Update March 28, 2008
2.0 Basis of Planning
Flathead County Growth Plan 2006. The County’s growth plan was recently
revised, and will likely be adopted by the end of 2006. With regard to population,
the growth plan discusses historic population trends along with demographics,
and future population projections. Since 2000 Flathead County’s population has
increased at a relatively constant rate of approximately 2% per year. Between
2000 and 2005 the US Census estimates a population increase from 74,471 to
83,172 people, representing roughly a 12% increase over the first five years of
the decade. This growth rate is consistent with the growth experienced between
1990 and 2000. The growth plan estimates 2025 population at 111,740; this
equates to about 1.5% growth per year. However, since 1960 Flathead County
has grown an average of 2.1% per year. If this growth patterns continues to
2025, there will be 127,270 people living in the county (HDRa, 2006).
This is consistent with the assumption that future growth will occur more
aggressively near existing cities and city services and utilities, and less
aggressively in other areas of the county. For example in 2005, there were an
estimated 23,216 people living outside the major cities, towns, and study areas
for major cities, or 28%. If this growth patterns continues to 2025, there will be
127,270 people living in the county. If historic growth rates (2.1% since 1960)
continue, this could result in 21,195 people living outside cities and towns in
2025 or about 17%.
Transportation Planning Study 2006. The Kalispell Area Transportation Plan
(2006 Update) evaluated low, moderate, and high growth scenarios for Flathead
County. The moderate Growth scenario was selected as most likely to occur,
based on past trends and what has happened in other Montana community’s over
the past thirty years. The Transportation Plan Study Area Boundary closely
resembles this Utility Plan’s Study Area with only a few minor differences. The
Transportation plan predicts a Study Area 2030 population of 79,273 whereas
this Utility Plan predicts a 2030 population of 82,248. These population
projections match very closely, given the differences in Study Area Boundaries,
it is reasonable to say the Kalispell Area Transportation Plan (2006 Update)
supports the findings of the Kalispell Utility Plan Update with regard to
population growth.
2.2.4 Recommended Future Population Projections
After reviewing data gathered during meetings with City of Kalispell public works and
planning staff, analytical methods, and planning documents; the following conclusions
were made.
• Depending upon the analysis method, 2050 population estimates ranged
from 70,246 (growth at 1.3% per year) to 229,453 (growth at 4% per
year).
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 2-13
2.0 Basis of Planning
• According to City staff knowledge including future development
projects, zoning, land use, and probable population densities; theoretical
build out population is estimated at 194,164 (or approximately 3.5%
growth per year).6
• The project team chose to use a growth rate of 3% per year. This
corresponds closely with the city staff estimates for theoretical build out,
is lower than the aggressive 4.2% seen over the past 5 years, and it is
higher than historic growth rates of 1.3% per year (which are considered
unrealistically low for future conditions). In addition, analysis shows that
higher growth rates will likely be seen for the next 15-20 years (until
about 2025 to 2030), then may slow down according to demographic
trends.
In 2050 there will be an estimated
148,549 people living within the
defined study area boundary. This
corresponds to a growth rate of 3% per
year.
• Therefore, for the purpose of this facility plan, there will be an estimated
70,948, 95,345, and 148,549
people living within the study
area by 2025, 2035, and
2050, respectively. These
estimates will be used in
utility system analysis and
capital improvements planning.
2.2.5 Land Use (Post-Development)
The post-development land use projections for the hydraulic analysis were based the
2035 population projections described in Section 2.2.2 and the City of Kalispell
residential zoning classifications. Four population ranges were used included; Range 1
(0 – 450 people), Range 2 (451-1,850 people), Range 3 (1,851-2,650 people) and Rang 4
(2,651 – 4,150 people). A correlation to the Kalispell Residential Zoning was established
based on the descriptions of the districts from the Kalispell Zoning Ordinance7. The
population land use map as shown in Figure 2.3 was used for the post-developed
hydraulic analysis included in Section 4 of this report.
6 The theoretical build out would occur if all available land was built upon according to likely densities. This
theoretical build out does not consider political or ownership limitations that may exist or be placed on
properties in the subject area; therefore, estimated future population should not exceed the theoretical build
out.
7 City of Kalispell Zoning Ordinance No. 1460, Kalispell Planning Department, November 2006.
2-14 City of Kalispell Storm Water Facility Plan Update March 28, 2008
2.0 Basis of Planning
Table 2.2-4: Post-Development Land Use and Population Correlation
Kalispell
Residential
Zoning Kalispell Zoning Use District
Lot Size
(acre, ft2)
Impervious
(%)
Population
Range
R-1 Suburban Residential 1.0, 43,560 35 0 - 450
R-2 Single-Family Residential 0.22, 9,600 35 451 – 1,850
R-3 Urban Single-Family Residential 0.16, 7,000 40 1,851 – 2,650
R-4 Two-Family Residential 0.14, 6,000 45 2,651 – 4,150
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 2-15
2.0 Basis of Planning
Figure 2.3 2035 Population Land Use Map
2.3 Storm Water Management and Design Standards
2.3.1 Introduction
Since the study area of this report is outside the Kalispell City Limits, the effective storm
water management ordinance and design standards would need to be amended to include
the study area of this report located in Flathead County. This would require a
2-16 City of Kalispell Storm Water Facility Plan Update March 28, 2008
2.0 Basis of Planning
cooperative approach with Flathead County to accept and adopt the storm water
management and design standards and develop an agreement with Flathead County for
the areas outside of the existing City Limits that are likely to be developed and
potentially annexed to the City in the future.
2.3.2 Water Quantity (Runoff Control)
2.3.2.1 Regional Detention Ponds
Where possible, regional detention ponds (DP) would be located along a major storm
water conveyances and the outlet of the pond would discharge to the conveyance. For
storage calculations, the 100-year, 24-hour storm would be used. The storm water
detention pond would be sized to store the difference between the existing and post-
development 100-year, 24-hour volume. A low-level outlet structure would be provided
with a discharge rate no greater than the respective 2-, 10-, 50-, and 100-year peak
discharge rates for existing conditions. An overflow spillway or structure would be
provided to release the 100-year, 24-hour peak discharge rate for the post-development
condition. Fencing around the perimeter of the ponds may be required for public safety
at some of the sites.
2.3.2.2 Closed Basins
Closed basins (CB) are drainage basins that do not have an outlet. Closed basins would
drain to a retention pond. Since there would not be an outlet a drainage easement would
be required to provide for the retention pond areas. Closed basins could serve as
enhanced or future wetlands to mitigate existing wetland impacts and they could also
provide storm water treatment from future developments in the drainage basin. Fencing
around the perimeter of the basin may be required for public safety at some of the sites.
2.3.2.3 Storm Water Management Ponds
Some drainage basins located along the rivers and creeks have a general sheet flow runoff
pattern towards the river or creek. Regional detention ponds are not feasible for these
drainage basins due to the topography of the basin and lack of a point discharge.
Therefore, site-specific storm water management ponds (SWMP) would be used in these
areas to control the 100-year runoff and would need to be incorporated into the design of
future developments. Fencing around the perimeter of the ponds may be required for
public safety at some of the sites.
2.3.2.4 Existing Natural Drainage Ways
Natural drainage ways exist throughout the study area. These drainage ways are the low
point of the drainage basins and storm water is naturally conveyed along their natural
alignment. The preservation of these drainage ways would be needed for the
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 2-17
2.0 Basis of Planning
2-18 City of Kalispell Storm Water Facility Plan Update March 28, 2008
management and control of storm water runoff. The City of Kalispell has indicated that
the preservation of these drainage ways would be completed through the planning and
permitting requirements of future developments in the drainage basin.
2.3.3 Best Management Practices
It is recommended that the City develop a policy to address storm water quality and target
best management practices (BMP’s) to reduce the discharge of pollutants to local surface
waters. The pollutants of primary concern for local surface waters are sediment and
nutrients. Best management practices designed to reduce sediment and nutrients should
be required for construction site erosion and sedimentation control and included in new
development plans for post construction runoff. This approach to managing water quality
impacts from storm water discharges would be consistent with the requirement of the
EPA Phase II Storm Water Regulations.
Water quality design criteria for sizing best management practices for reducing pollutant
loadings are focused on smaller, more frequent rainfall/runoff events than the hydraulic
design criteria for the Facility Plan Update discussed earlier which is intended to prevent
urban flooding. Water quality based design criteria are intended for sizing of BMP’s to
capture and treat a portion of the runoff generated from a design storm of specified
frequency and duration. Typical water quality design criteria are to capture the first 0.33-
inch to 1-inch of storm water runoff and route it to water quality BMP’s for treatment.
2.3.4 Management and Policy Recommendations
Whenever new development occurs, storm water management requirements should be
required as part of the design. These measures would restrict runoff from new
developments to the existing (historic) level for all recurrence intervals, from the 2-year
to the 100-year, in order to avoid overloading existing facilities or create storm water
flooding on downstream properties.
It is suggested that the City of Kalispell and Flathead County consider restricting runoff
from new developments to the historic level for all recurrence intervals, from the 2-year
to the 100-year, in order to avoid further overloading of existing facilities.
Church Dr.
Stillwater Rd.
Farm to Market Rd.
Whitefish Stage Rd.
Trumble Creek Rd.
Birch Grove Rd.
West Valley Dr.
Rose Crossing
W. Reserve Dr.W. Springcreek Dr.
Cemetary Rd.
West Valley Dr.
W. Springcreek Dr.
West Valley Dr.
West Valley Dr.
W. Reserve Dr.
Foy's Lake
Lore Lake
Middle Foy Lake
Lower Foy Lake
Stillwater River
Flathead River
Ashley Creek
Whitefish River
x
F la t h e a d Ri v e r
Flathead River
Flathead River
Stillwater River
F
l
a
t
h
e
a
d
Riv
e
r
F l a t h e a d Ri v e r
US2
US93
MT35
MT82
Evergreen Sewer District
Legend
Study Area Boundary
Kalispell City Limits 0 1 20.5 Miles
F i g u r e 2 -4 S t u d y A r e aFigure 2 -4 S t u d y A r e a
City of Kalispell
Storm Water
Facility Plan Update
City of Kalispell
City of Kalispell
1 inch equals 6,000 feet
Church Dr.
Stillwater Rd.
Farm to Market Rd.
Whitefish Stage Rd.
Trumble Creek Rd.
Birch Grove Rd.
West Valley Dr.
Rose Crossing
W. Reserve Dr.W. Springcreek Dr.
Cemetary Rd.
West Valley Dr.
W. Springcreek Dr.
West Valley Dr.
West Valley Dr.
W. Reserve Dr.
Foy's Lake
Lore Lake
Middle Foy Lake
Lower Foy Lake
Stillwater River
Fla t h e a d Ri v e r
Ashley Creek
Whitefish River
x
Flathead River
Flathead River
Flathead River
Stillwater River
Flathead River
Legend
Stream
National Forest
Lake
Wetland
Floodplain
Road
Airport
Evergreen Sewer
Kalispell City Limits 0 1 20.5 Miles
F i g u r e 2 -5Figure 2 -5
P h y s i c a l C h a r a c t e r i s t i c sPhysical C h a r a c t e r i s t i c s
City of Kalispell
Storm Water
Facility Plan Update
City of Kalispell
City of Kalispell
1 inch equals 6,000 feet
East Whitefish RiverExisting Population: 8209
Theoretical Build-OutPopulation: 40000
2035 Population: 8224
West Kalispell
Existing Population: 3382
Theoretical Build-OutPopulation: 41686
2035 Population: 19938
North KalispellExisting Population: 3647
Theoretical Build-OutPopulation: 21700
2035 Population: 16907
South Kalispell
Existing Population: 2513
Theoretical Build-OutPopulation: 16000
2035 Population: 6474
West Stillwater River
Existing Population: 1048
Theoretical Build-OutPopulation: 29000
2035 Population: 10084
East Kalispell
Existing Population: 2003
Theoretical Build-OutPopulation: 6000
2035 Population: 4107
Existing Population: 0
Theoretical Build-OutPopulation: 0
2035 Population: 0
Foy's Lake
Lore Lake
Middle Foy Lake
Lower Foy Lake
US2
US93
MT35
MT82
Church Dr.
Stillwater Rd.Farm to Market Rd.
Whitefish Stage Rd.
Trumble Creek Rd.
Birch Grove Rd.
West Valley Dr.
Rose Crossing
W. Reserve Dr.
W. Springcreek Dr.
Cemetary Rd.
W. Springcreek Dr.
West Valley Dr.
West Valley Dr.
W. Reserve Dr.
Stillwater River
Fla t h e a d Riv e r
Ashley Creek
W
hitef
ish
R
ive
r
x
Flathead River
Flathead River
Flathead River
S
till
w
a
t
e
r
R
i
v
e
r
Flathead River
CITY OF KALISPELL
Existing Population: 14223
Theoretical Build-Out Population: 29614
2035 Population: 29614
Legend
Kalispell City Limits
Highway 93 Bypass
Streams
Lake
Analysis Zones
East Kalispell
East Whitefish River
North Kalispell
South Kalispell
West Kalispell
West Stillwater River 0 1 20.5 Miles
F i g u r e 2 -6Figure 2 -6
P o p u l a t i o n G r o w t hPopulation G r o w t h
City of Kalispell
Storm Water
Facility Plan Update
City of Kalispell
Note:
Existing population corresponds to Year 2000.
1 inch equals 6,000 feet
3.0 Regulations
3.0 Regulations
3.1 Introduction
This section of the Facility Plan summarizes the local, state and federal, and Phase II
storm water regulations and permits that the City of Kalispell has or plans to implement.
3.2 Local Regulations
The City of Kalispell Ordinance No. 1600, Storm Water Discharges Resulting from
Construction and Land Disturbance Activities was approved by City Council in April
2007 and became active on May 2, 2007. This ordinance requires a Storm Water
Management Permit be obtained from the City of Kalispell Public Works Department by
a responsible party engaging in any land disturbing activity, or for any construction
activity in the City of Kalispell. This permit is in addition to the Montana Department of
Environmental Quality (DEQ) General Permit for Discharges Associated with
Construction Activities. Both permits are required for land disturbance equal to or
greater than one acre.
If the land disturbing activity is less than one acre then it is not required to comply with
MPDES general permit number MTR100000, but it shall prepare and submit a Storm
Water Management Plan, for review and approval by the City of Kalispell Public Works
Department in accordance with Ordinance No. 1600. Ordinance No. 1600 is included in
Appendix A of the Storm Water Facility Plan Update.
3.3 State Regulations
Montana Department of Environmental Quality (DEQ) requires a General Permit for
Discharges Associated with Construction Activities, Permit No. MTR100000. This
Montana Pollutant Discharge Elimination System (MPDES) permit is required for all
projects or activities which meet the definition of “storm water discharge associated with
construction activity” as defined in Part VI of the permit. Owners or operators of
construction activities or sites that may discharge storm water to state surface waters must
submit a complete Notice of Intent (NOI) package and annual fees to the DEQ at the
following address:
Department of Environmental Quality
Water Protection Bureau
P.O. Box 200901
Helena, MT 59620-0901
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 3-1
3.0 Regulations
3.4 MS4 Phase II Permitting
The City of Kalispell is listed as a governmental entity located in an urbanized area (UA)
having a population of at least 10,000 and a population density of at least 1,000 people
per square mile. The National Pollutant Discharge Elimination System (NPDES)
permitting authority is the Montana Department of Environmental Quality Water
Protection Bureau (DEQ). DEQ has developed a set of designation criteria for municipal
separate storm sewer systems (MS4s) and is applying them to all MS4 listed entities. The
permitting authority is required to evaluate such entities but is not required to designate
them into the program unless they meet the designation criteria. The City of Kalispell
has been designated as an entity that must comply with the Montana Pollutant Discharge
Elimination System (MPDES) MS4 Storm Water Regulations.
DEQ has developed designation criteria and permitting rules for the Phase II Storm Water
Program in Montana. Typical designation criteria include:
• Discharge to sensitive waters
• High population density
• High growth or growth potential
• Contiguity to an urbanized area (UA)
• Significant contributor of pollutants to waters of the United States
• Ineffective protection of water quality concerns by other programs
The City of Kalispell and Montana Department of Transportation (MDT) has complied
with the permit by submitting a co-application in February 2006 and was issued a
NPDES General Permit number MTR040005 on July 2006. The next step is for the city
to develop, implement and enforce a Storm Water Management Program (SWMP) to
reduce the discharge of pollutants to the maximum extent possible. Included in the
program would best management practices (BMP’s) for each of the six minimum control
measures which include:
1. Public education and outreach on storm water impacts.
2. Public participation/involvement to the program.
3. Illicit discharge detection and elimination of the storm water system.
4. Construction site storm water runoff control.
5. Post-construction storm water management in new development or
redevelopment sites.
6. Pollution prevention/good housekeeping for municipal operations including staff
training on pollution prevention measures and techniques.
3-2 City of Kalispell Storm Water Facility Plan Update March 28, 2008
3.0 Regulations
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 3-3
The City of Kalispell and MDT are developing the Storm Water Management Program,
involving six minimum control measures to control pollutants in storm water to the
maximum extent practical.
The co-application submitted by the City of Kalispell and MDT for the MPDES General
Permit and General Permit number MTR040005 are included in the Appendix of the
Storm Water Facility Plan Update.
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
4.0 Storm Water Major Conveyance, Detention and
Discharge Analysis
4.1 Introduction
This section of the Facility Plan summarizes the results and findings of the evaluation of
the existing and post-development storm drainage analysis for the study area. The study
area includes areas outside of the existing City Limits that are likely to be developed and
annexed to the City in the future. The storm drainage evaluation utilized aerial and land
use mapping developed by the City of Kalispell to define and characterize drainage
basins and provide existing and post developed characterization and runoff estimation.
Planning level recommendations for backbone infrastructure is provided for the study
area.
4.2 System Analysis Methodology
The USDA Small Watershed Hydrology model TR-20 was used for the conceptual
modeling of the storm water runoff. The TR-20 computer program was used to provide
the hydrologic analyses of each watershed under existing and post-development
conditions.
The TR-20 program was designed by the USDA Natural Resource Conservation Service
(NRCS) and is a hydrologic model that is based on a storm event applied to a watershed.
It can be used to analyze multiple storm events and to assist in the hydrologic evaluation
of flood events. The TR-20 model was used versus the manual TR-55 model because
TR-20 offers more capabilities as development occurs within the project study area and
the hydraulic input parameters change. TR-20 incorporates all of the TR-55 Urban
Hydrology for Small Watersheds methodology.
The hydrologic input parameters for each drainage basin included the drainage area
(Area), curve number (CN) and time of concentration (Tc). The output consists of peaks
discharge rate in cubic feet per second (cfs) and the runoff depth for each drainage basin
in inches. Runoff volumes for each catchment drainage basin were calculated by
multiplying the runoff depth in feet by the drainage area in acres to obtain storm water
runoff volume for the basin in acre-feet.
4.2.1 Drainage Area
The drainage area (Area) for each catchment drainage basin was determined using
ArcHydro GIS mapping of the updated land use and topographic mapping from the City
of Kalispell and USGS quadrangle mapping of the study area. The total drainage area
that contributes storm water runoff to the study area boundary is approximately 63 square
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 4-1
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
miles. The study area was divided into six sub-areas including: a) East Whitefish River,
b) North Kalispell, c) West Stillwater River, d) West Kalispell, e) East Kalispell and f)
South Kalispell as shown in Figure 4.2-1. A total of 60 catchment drainage basins were
developed for the study area and are shown in Figure 4.2-2.
4.2.2 Curve Number (CN)
The curve number is a measure of the expected infiltration rate for a specific hydrologic
soils group and land use. Urbanization typically increases the CN value and increases
both the peak rate of runoff and volume of runoff.
The curve number (CN) for each basin was based on the hydrologic soil group (HSG),
land use or cover type/treatment, hydrologic conditions, and antecedent runoff condition
(ARC). The curve number for each basin was determined by the spatial weighted
average of the land use mapping for both existing and post-development conditions. CN
values for the existing land uses were based on weighted average of the CN shown in
Table 4.2-1. CN values for the post-development land uses were based on the weighted
average of the CN shown in Table 4.2-2. The CN for existing and post-development land
use are shown in Figures 4.2-3 and 4.2-4, respectively. The Hydrologic Soils Groups are
shown in Figure 4.2-5 and the individual soils groups from the NRCS Soils Study8 are
shown on Figure 4.2-6.
8 Natural Resources Conservation Service, USDA, MT651 Soils Survey of Sanders and Parts of Lincoln
and Flathead Counties, Montana, 1996.
4-2 City of Kalispell Storm Water Facility Plan Update March 28, 2008
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
Table 4.2-1: Existing Land Use CN Values
Hydrologic Group Land Use
ID Land Use Description A B C D
11 RESIDENTIAL 61 75 83 87
12 COMMERCIAL/SERVICES 89 92 94 95
13 INDUSTRIAL 81 88 91 93
14 TRANSPORTATION/UTIL 83 89 92 93
15 IND/COMM COMPLEXES 81 88 91 93
16 MIXED URBAN/BUILT-UP 80 87 91 93
17 OTHER URBAN/BUILT-UP 49 69 79 84
21 CROP/PASTURE 42 64 75 81
22 ORCHARD/NURSERY 43 65 76 82
23 CONFINED FEEDING 59 74 82 86
24 OTHER AG 67 77 83 87
31 GRASS RANGELAND 39 61 74 80
32 BRUSH RANGELAND 35 56 70 77
33 MIXED RANGELAND 47 64 74 81
41 DECIDUOUS FOREST 43 65 76 82
42 EVERGREEN FOREST 36 60 73 79
43 MIXED FOREST 38 62 75 81
49 EVERGREEN FOREST, RECODED FROM MIXED 30 55 70 77
51 STREAM/CANAL 100 100 100 100
52 LAKE 100 100 100 100
53 RESERVOIR 100 100 100 100
61 WETLAND 30 58 71 48
62 WETLAND 30 58 71 48
71 DRY SALT FLATS 39 61 74 80
72 BEACHES 39 61 74 80
73 SAND 39 61 74 80
74 EXPOSED ROCK 98 98 98 98
75 MINES/QUARRIES 76 85 89 91
77 MIXED BARREN LAND 77 86 91 94
76 TRANSITIONAL 47 64 74 81
81 SHRUB TUNDRA 47 64 74 81
82 GRASS TUNDRA 47 64 74 81
83 BARE TUNDRA 47 64 74 81
84 WET TUNDRA 47 64 74 81
85 MIXED TUNDRA 47 64 74 81
91 SNOWFIELD 100 100 100 100
92 GLACIER 100 100 100 100
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 4-3
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
Table 4.2-2: Post-Development Land Use CN Values
Hydrologic Group District Classification Average %
Impervious A B C D
R-1 SUBURBAN RESIDENTIAL 35 51 68 79 84
R-2 SINGLE-FAMILY RESIDENTIAL 35 57 72 81 86
R-3 URBAN SINGLE-FAMILY RESIDENTIAL 40 61 75 83 87
R-4 TWO-FAMILY RESIDENTIAL 45 66 78 85 88
R-5 RESIDENTIAL/PROFESSIONAL OFFICE 50 69 80 86 89
RA-1 LOW DENSITY RESIDENTIAL APARTMENT 45 66 78 85 88
RA-2 HIGH DENSITY RESIDENTIAL APARTMENT 50 77 85 90 92
RA-3 RESIDENTIAL APARTMENT/OFFICE 50 71 81 87 90
H-1 HEALTH CARE 45 66 78 85 88
B-1 NEIGHBORHOOD BUFFER DISTRICT 50 70 80 86 89
B-2 GENERAL BUSINESS -- 66 78 85 88
B-3 COMMUNITY BUSINESS -- 71 81 87 90
B-4 CENTRAL BUSINESS -- 89 92 94 95
B-5 INDUSTRIAL-COMMERCIAL -- 60 74 86 89
I-1 LIGHT INDUSTRIAL -- 81 88 91 93
I-2 HEAVY INDUSTRIAL -- 89 92 94 95
P-1 PUBLIC (Ord 1175, 3-19-1992) 45 49 69 79 84
4.2.3 Time of Concentration (Tc)
The time of concentration (Tc) is the time for runoff to travel from the hydraulically most
distant point in the watershed to the outlet point of the drainage basin. Tc influences the
shape and peak of the runoff hydrograph. Urbanization usually decreases Tc, and
therefore increases the peak discharge rate. Tc can be increased as a result of ponding
behind small embankments or inadequate drainage systems, including storm drain inlets
and cross drain culverts. Tc can also be increased by the reduction of land slope through
grading.
The Tc for the Storm Water Facility Plan Update was calculated using the ArcHydro GIS
topographic mapping computer program to compute equations (1), (2), and (3) for the
parameters shown in Table 4.2-3.
Equation (1): Equation (2): Equation (3):
LcLct3
5Tor 0.6
tT ⋅==()
0.5
0.70.8
L Y1900
1SLt⋅
+⋅=CN
CN101000S⋅−=
4-4 City of Kalispell Storm Water Facility Plan Update March 28, 2008
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
Table 4.2-3: Time of Concentration
Parameter Units Description Calculated From:
CN -
Curve Number associated with pre- and
post-developed land use GIS spatial weighing
Y % Average slope of watershed basins GIS zonal statistics
L ft Length to divide \ longest flow path ArcHydro longest flow path analysis
S - Potential maximum retention Equation (1)
tL hrs Lag time Equation (2)
Tc hrs Time of concentration Equation (3)
4.3 Precipitation – Rainfall Runoff Estimation
4.3.1 Hydrology
The 100-year 24-Hour precipitation depths provided in the NOAA Atlas9 for the City of
Kalispell and summarized in Table 4.3-1 were used as the design precipitation event in
the USDA Small Watershed Hydrology TR-20 model for the modeling of the storm water
runoff. As was determined in the 2002 City of Kalispell Facility Plan, the Soil
Conservation Service (SCS) Unit Hydrograph method (now NRCS) better represents the
hydrology and resultant routing of the storm through the study basins. The SCS Unit
Hydrograph method accounts for the initial rainfall losses and infiltration rate of the soils,
as well as a more realistic time distribution of the rainfall. Based on a review of the
hydrological information, it was decided by the City that a design storm with 24-hour
duration would be used for the Storm Water Facility Plan Update. Reasons include as
development of the project area increases the drainage ways will become more sensitive
to flood volumes and water quality justifying that the 24-hour duration would be used for
the Facility Plan Update. The SCS Type I storm distribution was used for the City of
Kalispell as in the 2002 Facility Plan and is the prescribed storm as defined in the SCS
Engineering Field Manual10. The Type I storm is characterized by the distribution curve
shown in Figure 4.3-1.
9 U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Weather
Service, Precipitation-Frequency Atlas of the Western United States, NOAA Atlas 2, Volume I-Montana,
1973.
10 U.S. Department of Agriculture, Soil Conservation Service, Engineering Field Manual, Chapter 2,
Supplemental 1, Estimating Runoff in Montana.
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 4-5
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
Table 4.3-1: City of Kalispell 24-Hour Precipitation Depths
Recurrence Interval
24-Hour
Precipitation Depth
(inches)
2-year 1.4
10-year 2.0
25-year 2.4
50-year 2.8
100-year 3.0
Figure 4.3-1 SCS Type I Storm Distribution
100-year, 24-Hr SCS Type I Rainfall Distribution, Kalispell Montana
0
0.5
1
1.5
2
2.5
3
0 5 10 15 20
Time (Hr)
Pr
e
c
i
p
i
t
a
t
i
o
n
(
I
n
c
h
e
s
)
4.3.2 Recurrence Interval for Design of Regional Facilities
In accordance with the 2002 City of Kalispell Facility Plan, the 100-year design storm
was used for computing the peak discharge rates for the major drainage way capacities
and runoff volumes for the regional detention ponds and closed basins. Additionally, this
4-6 City of Kalispell Storm Water Facility Plan Update March 28, 2008
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
recurrence interval will provide drainage way capacities that are consistent with FEMA
requirements for floodplain delineations in Flathead County.
Regional detention ponds with an outlet structure and discharge conveyances were sized
based on the storage difference between the existing and post-developed 100-year 24-
hour volumes as determined using the USDA TR-20 computer program.
For closed basins where the opportunities for an outlet structure and discharge
conveyances does not exist, the storage volume was computed by using the post-
developed 100-year 24-hour volume as determined using the USDA TR-20 computer
program.
4.4 Storm Water Major Conveyances, Detention and Discharge
Analysis
4.4.1 Storm Water Study Area
The total drainage area that contributes storm water runoff to the study area boundary is
approximately 62.6 square miles or 40,429 acres. The study area was divided into six
sub-areas including: a) East Whitefish River, b) North Kalispell, c) West Stillwater
River, d) West Kalispell, e) East Kalispell and f) South Kalispell as shown in Figure 4.2-
1. A total of 60 catchment drainage basins were developed for the study area and are
shown in Figure 4.2-2.
The storm water volumes and peak discharge rates from the TR-20 analysis described in
Section 4.2 for the six sub-areas are discussed in more detail in the following sections.
4.4.2 Storm Water Major Conveyance, Detention and Discharge System
Analysis
4.4.2a East Whitefish River Study Area
The East Whitefish River catchment consists of the project study area northeast of the
City of Kalispell and Whitefish River along U.S. Highway 2. The study area as shown in
Figure 4.4.2a-1 is approximately 5,887 acres or 9.2 square miles and consists of primarily
agricultural crop and pasture land with small random residential developments located at
the southern boundary north of the Evergreen community. Glacier Park International
Airport, a transportation facility for the City of Kalispell and Flathead County, is located
near the northern boundary.
Major rivers and creeks located in the East Whitefish River study area include the
Whitefish River, Trumbull Creek, Spring Creek and Flathead River. The Whitefish River
flows from north to south along the west boundary of the sub-area. The FEMA Flood
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 4-7
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
Insurance Study (FIS)11 has been completed on the Whitefish and Flathead Rivers and
includes detailed floodplain mapping from the north study area boundary to the City of
Kalispell. Trumbull and Spring Creeks flow from north to south and have approximate
study FIS mapping within the study area.
4.4.2a.1 East Whitefish River Storm Water Runoff Estimation and
Critical Drainage Way Identification
The East Whitefish River study area was delineated into ten drainage basins based on the
topographic mapping from the City of Kalispell and USGS quadrangle mapping of the
study area. The hydraulic and hydrologic parameters of each drainage basin are shown
in Table 4.4.2a-1.
Table 4.4.2a-1: East Whitefish Catchment Drainage Basins
Area CN Y L S tL Tc Basin
ID (mi2) (acre) Existing Post- (%) (ft) (-) (hrs) (hrs)
106 0.50 320 64 68 0.21 7,820 5.584 5.535 9.226
107 0.64 410 67 68 0.25 9,423 4.967 5.539 9.232
108 2.33 1,491 64 69 0.43 21,273 5.660 8.786 14.643
109 0.85 544 64 71 0.68 11,798 5.725 4.388 7.314
121 0.84 538 65 69 0.19 11,424 5.344 7.689 12.815
146 0.84 538 65 69 0.34 2,463 5.332 1.700 2.834
151 0.35 224 65 73 0.24 2,095 5.333 1.757 2.928
152 0.52 333 65 68 0.37 5,274 5.273 2.962 4.937
153 1.36 870 64 71 0.62 5,522 5.628 2.479 4.131
157 0.97 620 72 73 0.29 9,811 3.807 4.542 7.570
Total 9.20 5,887 Total 86,903
CN: SCS Runoff Curve Number
Y: Average Slope of watershead basin (%)
L: Length to basin divide or longest flow path (feet)
tL: Lag Time (hrs)
S: Potential maximum retention (unit less)
Tc: Time of concentration (hrs)
The results of the East Whitefish TR-20 computation modeling for the existing and post-
developed conditions in each of the ten drainage basins are shown in Table 4.4.2a-2 and
Table 4.4.2a-3, respectively. The differences between the existing and post-developed
100-year runoff estimation is shown in Table 4.4.2a-4
11 Flood Insurance Study, Flathead County MT, Federal Emergency Management Agency (FEMA)
Community Number 300023, 1985.
4-8 City of Kalispell Storm Water Facility Plan Update March 28, 2008
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
Table 4.4.2a-2: East Whitefish Existing 100-year Runoff
Input Output
Basin Area Basin Area TC Qpeak Runoff Depth Runoff Volume Basin
(sq. miles) (acres) CN (hrs) (cfs) (inches) (acre-ft)
106 0.50 320 64 9.226 9.89 0.458 12.21
107 0.64 410 67 9.232 16.08 0.577 19.69
108 2.33 1,491 64 14.643 39.94 0.466 57.91
109 0.85 544 64 7.314 17.98 0.465 21.08
121 0.84 538 65 12.815 16.26 0.498 22.31
146 0.84 538 65 2.834 26.59 0.504 22.58
151 0.35 224 65 2.928 10.96 0.501 9.35
152 0.52 333 65 4.937 13.73 0.500 13.87
153 1.36 870 64 4.131 34.33 0.467 33.87
157 0.97 620 72 7.570 38.55 0.804 41.51
Total 9.20 5,887 Total 254.39
Table 4.4.2a-3: East Whitefish Post-Developed 100-year Runoff
Input Output
Basin Area Basin Area TC Qpeak Runoff Depth Runoff Volume Basin
(sq. miles) (acres) CN (hrs) (cfs) (inches) (acre-ft)
106 0.50 320 68 9.226 13.57 0.616 16.43
107 0.64 410 68 9.232 17.36 0.619 21.13
108 2.33 1,491 69 14.643 56.68 0.667 82.89
109 0.85 544 71 7.314 32.04 0.756 34.27
121 0.84 538 69 12.815 21.56 0.662 29.66
146 0.84 538 69 2.834 41.09 0.668 29.93
151 0.35 224 73 2.928 24.37 0.853 15.92
152 0.52 333 68 4.937 18.24 0.622 17.25
153 1.36 870 71 4.131 67.04 0.759 55.05
157 0.97 620 73 7.570 41.64 0.853 44.13
Total 9.20 5,887 Total 346.65
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 4-9
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
Table 4.4.2a-4: East Whitefish Difference in 100-year Runoff
Existing Post-Developed Difference
Q Runoff Volume Q Runoff Volume Q Runoff Volume Basin
(cfs) (acre-ft) (cfs) (acre-ft) (cfs) (acre-ft)
106 * 9.89 12.21 13.57 16.43 3.68 4.21
107 * 16.08 19.69 17.36 21.13 1.28 1.43
108 * 39.94 57.91 56.68 82.89 16.74 24.98
109 * 17.98 21.08 32.04 34.27 14.06 13.19
121 * 16.26 22.31 21.56 29.66 5.30 7.35
146 26.59 22.58 41.09 29.93 14.50 7.35
151 10.96 9.35 24.37 15.92 13.41 6.57
152 13.73 13.87 18.24 17.25 4.51 3.38
153 34.33 33.87 67.04 55.05 32.71 21.18
157 * 38.55 41.51 41.64 44.13 3.09 2.62
Total 254.39 Total 346.65 Total 92.26
* Basins with potential regional detention ponds.
4.4.2a.2 East Whitefish River Study Area Storm Water Runoff Quantity
Control Recommendations
Based on the topography of the East Whitefish River study area and existing drainage
conveyances, it is recommended that regional detention ponds be used to control post-
developed runoff in basins 106, 107, 108, 109, 121, and 157 as shown in Figure 4.4.2a-1.
In general, the proposed regional detention ponds (DP) would be located along a major
storm conveyance and the outlet from the basin would discharge to the major
conveyance. For storage calculations, the 100-year, 24-hour storm would be used. The
storm water detention pond would be sized to store the difference between the existing
and post-development 100-year, 24-hour volume. A low-level outlet structure would be
provided with a discharge rate no greater than the 100-year peak for 24-hour existing
conditions. An overflow spillway or structure would be provided to release the 100-year,
24-hour peak discharge rate for the post-development condition.
The probable construction cost shown in Tables 4.4.2a-5 for these proposed regional
detention ponds is based on the difference in 100-year volume between the existing and
post-developed conditions and a maximum pond depth of 3-feet. Detailed probable cost
estimates for the ponds are included in the Appendix of the Storm Water Facility Plan
Update.
The capital improvement cost summary does not include the costs necessary to acquire
easements for the existing natural drainage ways. The City of Kalispell has indicated that
the preservation of these drainage ways would be completed through the planning and
permitting requirements of future developments in the drainage basin. Based on the TR-
20 analysis described in Section 4.2 and listed in Table 4.4.2a-1, the total length of
4-10 City of Kalispell Storm Water Facility Plan Update March 28, 2008
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
drainage ways from the basin divides to the outlet for the East Whitefish Study Area is
approximately 86,903 feet or 16.5 miles.
Table 4.4.2a-5: East Whitefish Facility Probable Cost Summary
Facility
ID
100 -year
Volume
(acre-ft)
Pond Area
(acres)
100-year
Peak
Dischage
Rate (cfs)
Outlet
Pipe
Diameter
(inches)
Estimated
Regional
DP Cost
Estimated
SWMP
Cost
Total
Probable
Cost
DP-106 4.21 1.4 9.89 24 $442,000 $0 $442,000
DP-107 1.43 0.5 16.08 24 $268,000 $0 $268,000
DP-108 24.98 8.3 39.94 42 $1,881,000 $0 $1,881,000
DP-109 13.19 4.4 17.98 36 $1,091,000 $0 $1,091,000
DP-121 7.35 2.5 16.26 24 $640,000 $0 $640,000
SWMP-146 7.35 2.5 26.59 36 $0 $724,000 $724,000
SWMP-151 6.57 2.2 10.96 24 $0 $591,000 $591,000
SWMP-152 3.38 1.1 13.73 24 $0 $391,000 $391,000
SWMP-153 21.18 7.1 34.33 36 $0 $1,593,000 $1,593,000
DP-157 2.62 0.9 38.55 42 $467,000 $0 $467,000
Total 92.26 30.8 Total $4,789,000 $3,299,000 $8,088,000
DP: Proposed Regional Detention Pond with Outlet
SWMP: Storm Water Management Ponds for Future Developments
Basins 146, 151, 152 and 153 are located along the Whitefish River, Trumbull and Spring
Creeks and the Goodrich Bayou. These basins do not have well-established existing
drainage conveyances and generally have a sheet flow runoff pattern towards the river or
creeks. Regional detention ponds are not feasible for these drainage basins. Therefore,
site-specific storm water management ponds (SWMP) to control the 100-year runoff in
these areas would need to be incorporated into the design of future developments. The
probable cost summary listed in Table 4.4.2a-5 for these storm water management ponds
are based on the difference in 100-year volume and a maximum depth of 3-feet.
4.4.2b North Kalispell Study Area
The North Kalispell catchment consists of the project study area north of the City of
Kalispell between the Stillwater and Whitefish Rivers. The U.S. Highway 93 alignment
is on the west third and Whitefish Stage Road is located in the east third of the study area.
The study area as shown in Figure 4.4.2b-1 is approximately 7,966 acres or 12.4 square
miles and consists of primarily agricultural crop and pasture land with residential
developments located adjacent to the Kalispell City limits. The County Estates
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 4-11
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
subdivision and the Big Mountain Golf Club are located near the southern boundary and
Kalispell City Limits of the study area.
The Stillwater and Whitefish Rivers flow from north to south along the west and east
respective study area boundaries of the sub-area. The FEMA Flood Insurance Study
(FIS) 12 detailed mapping has been completed on the Whitefish and Stillwater Rivers and
includes detailed mapping from the north study area boundary to the City of Kalispell.
4.4.2b.1 North Kalispell Storm Water Runoff Estimation and Critical
Drainage Way Identification
The North Kalispell study area was delineated into twelve drainage basins based on the
topographic mapping from the City of Kalispell and USGS quadrangle mapping of the
study area. The hydraulic and hydrologic parameters of each drainage basin are shown
in Table 4.4.2b-1.
Table 4.4.2b-1: North Kalispell Catchment Drainage Basins
Area CN Y L S tL Tc Basin
ID (mi2) (acre) Existing Post (%) (ft) (-) (hrs) (hrs)
102 2.95 1887 62 63 6.10 29,306 6.030 3.127 5.211
103 2.77 1770 62 66 4.66 22,646 6.193 2.959 4.931
104 1.30 834 52 60 2.01 12,897 9.097 3.639 6.064
105 1.11 712 51 61 2.85 13,468 9.450 3.243 5.405
116 0.32 204 61 65 1.73 4,408 6.445 1.342 2.236
117 0.28 178 62 67 1.89 7,814 6.069 1.957 3.262
118 0.87 557 56 63 1.94 13,260 7.737 3.420 5.699
119 0.55 351 58 66 0.71 11,813 7.280 4.972 8.287
120 0.83 530 57 66 1.12 3,078 7.461 1.370 2.283
143 0.30 193 70 77 2.41 2,230 4.241 0.516 0.860
144 0.51 324 64 72 2.17 3,057 5.639 0.826 1.376
145 0.66 425 58 64 2.87 4,024 7.363 1.051 1.751
Total 12.5 7,968 Total 128,001
CN: SCS Runoff Curve Number
Y: Average Slope of watershead basin (%)
L: Length to basin divide or longest flow path (feet)
tL: Lag Time (hrs)
S: Potential maximum retention (unit less)
Tc: Time of concentration (hrs)
12 Flood Insurance Study, Flathead County MT, Federal Emergency Management Agency (FEMA)
Community Number 300023, 1985.
4-12 City of Kalispell Storm Water Facility Plan Update March 28, 2008
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
The results of the North Kalispell TR-20 computer modeling for the existing and post-
developed conditions in each of the twelve drainage basins are shown in Table 4.4.2b-2
and Table 4.4.2b-3, respectively. The differences between the existing and post-
developed 100-year runoff estimation is shown in Table 4.4.2b-4.
Table 4.4.2b-2: North Kalispell Existing 100-year Runoff
Input Output
Basin Area Basin Area TC Qpeak Runoff Depth Runoff Volume Basin
(sq. miles) (acres) CN (hrs) (cfs) (inches) (acre-ft)
102 3.0 1,888 62 5.212 56.88 0.397 62.46
103 2.8 1,773 62 4.931 54.22 0.397 58.65
104 1.3 832 52 6.065 9.08 0.125 8.67
105 1.1 710 51 5.405 6.95 0.106 6.28
116 0.3 205 61 2.237 6.63 0.360 6.14
117 0.3 179 62 3.262 6.07 0.391 5.84
118 0.9 557 56 5.699 9.35 0.216 10.02
119 0.6 352 58 8.290 6.73 0.264 7.74
120 0.8 531 57 2.284 10.58 0.244 10.80
143 0.3 192 70 0.860 31.19 0.712 11.39
144 0.5 326 64 1.376 18.44 0.467 12.70
145 0.7 422 58 1.752 9.82 0.272 9.57
Total 12.5 7,968 Total 210.27
Table 4.4.2b-3: North Kalispell Post-Developed 100-year Runoff
Input Output
Basin Area Basin Area TC Qpeak Runoff Depth Runoff Volume Basin
(sq. miles) (acres) CN (hrs) (cfs) (inches) (acre-ft)
102 3.0 1,888 63 5.212 62.88 0.432 67.97
103 2.8 1,773 66 4.931 80.47 0.544 80.37
104 1.3 832 60 6.065 19.96 0.331 22.95
105 1.1 710 61 5.405 19.18 0.362 21.43
116 0.3 205 65 2.237 11.00 0.502 8.57
117 0.3 179 67 3.262 10.51 0.579 8.65
118 0.9 557 63 5.699 18.06 0.429 19.91
119 0.6 352 66 8.290 13.27 0.535 15.69
120 0.8 531 66 2.284 32.06 0.543 24.04
143 0.3 192 77 0.860 60.40 1.069 17.10
144 0.5 326 72 1.376 49.99 0.806 21.92
145 0.7 422 64 1.752 21.68 0.467 16.44
Total 12.5 7,968 Total 325.03
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 4-13
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
Table 4.4.2b-4: North Kalispell Difference in 100-year Runoff
Existing Post-Developed Difference
Q Runoff Volume Q Runoff Volume Q Runoff Volume Basin
(cfs) (acre-ft) (cfs) (acre-ft) (cfs) (acre-ft)
102* 56.88 62.46 62.88 67.97 6.00 5.51
103* 54.22 58.65 80.47 80.37 26.25 21.72
104* 9.08 8.67 19.96 22.95 10.88 14.28
105* 6.95 6.28 19.18 21.43 12.23 15.16
116* 6.63 6.14 11.00 8.57 4.37 2.42
117* 6.07 5.84 10.51 8.65 4.44 2.81
118* 9.35 10.02 18.06 19.91 8.71 9.88
119* 6.73 7.74 13.27 15.69 6.54 7.95
120* 10.58 10.80 32.06 24.04 21.48 13.24
143 31.19 11.39 60.40 17.10 29.21 5.71
144 18.44 12.70 49.99 21.92 31.55 9.22
145 9.82 9.57 21.68 16.44 11.86 6.86
Total 210.27 Total 325.03 Total 114.76
* Basins with potential regional detention ponds.
4.4.2b.2 North Kalispell Study Area Storm Water Runoff Quantity
Control Recommendations
Based on the topography of the North Kalispell study area and existing drainage
conveyances, it is recommended that regional detention ponds be used to control post-
developed runoff in basins 102, 103, 104, 105, 106, 116, 117, 118, 119 and 120 as shown
in Figure 4.4.2b-1. In general, the proposed regional detention ponds (DP) would be
located along a major storm conveyance and the outlet from the basin would discharge to
the major conveyance. For storage calculations, the 100-year, 24-hour storm would be
used. The storm water detention pond would be sized to store the difference between the
existing and post-development 100-year, 24-hour volume. A low-level outlet structure
would be provided with a discharge rate no greater than the 100-year peak for existing
conditions. An overflow spillway or structure would be provided to release the 100-year,
24-hour peak discharge rate for the post-development condition.
The probable construction cost shown in Table 4.4.2b-5 for these proposed regional
detention ponds is based on the difference in 100-year volume between the existing and
post-development condition and a maximum pond depth of 3-feet. Detailed probable cost
estimates for the ponds are included in the Appendix of Facility Plan Update.
The capital improvement cost summary does not include the costs necessary to acquire
easements for the existing natural drainage ways. The City of Kalispell has indicated that
the preservation of these drainage ways would be completed through the planning and
permitting requirements of future developments in the drainage basin. Based on the TR-
4-14 City of Kalispell Storm Water Facility Plan Update March 28, 2008
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
20 analysis described in Section 4.2 and listed in Table 4.4.2b-1, the total length of
drainage ways from the basin divides to the outlet for the North Kalispell Study Area is
approximately 128,001 feet or 24.25 miles.
Table 4.4.2b-5: North Kalispell Facility Probable Cost Summary
Facility
ID
100 -year
Volume
(acre-ft)
Pond Area
(acres)
100-year
Peak
Dischage
Rate (cfs)
Outlet
Pipe
Diameter
(inches)
Estimated
Regional
DP Cost
Estimated
SWMP
Cost
Total
Probable Cost
DP-102 5.51 1.8 56.88 48 $880,000 $0 $880,000
DP-103 21.72 7.2 54.22 48 $1,898,000 $0 $1,898,000
DP-104 14.28 4.8 9.08 18 $1,066,000 $0 $1,066,000
DP-105 15.16 5.1 6.95 18 $1,176,000 $0 $1,176,000
DP-116 2.24 0.8 6.63 18 $301,000 $0 $301,000
DP-117 2.81 0.9 6.07 18 $337,000 $0 $337,000
DP-118 9.88 3.3 9.35 24 $798,000 $0 $798,000
DP-119 7.95 2.7 6.73 18 $660,000 $0 $660,000
DP-120 13.24 4.4 10.58 24 $1,010,000 $0 $1,010,000
SWMP-143 5.71 1.9 31.19 36 $0 $621,000 $621,000
SWMP-144 9.22 3.1 18.44 24 $0 $757,000 $757,000
SWMP-145 6.86 2.3 9.82 18 $0 $591,000 $591,000
Total 114.58 38.2 Total $8,062,000 $1,969,000 $10,031,000
DP: Proposed Regional Detention Pond with Outlet
SWMP: Storm Water Management Ponds for Future Developments
Basins 143, 144 and 145 would be located along the Stillwater River and generally have a
sheet flow runoff pattern towards the river. Regional detention ponds are not feasible for
these drainage basins. Therefore, site-specific storm water management ponds (SWMP)
in these areas to control the 100-year runoff would need to be incorporated into the
design of future developments. The probable cost summary listed in Table 4.4.2b-5 for
these storm water management ponds are based on the 100-year volume and a maximum
depth of 3-feet. Detailed cost estimates for the ponds are included in the Appendix of
Facility Plan Update.
Proposed detention ponds DP-118 and DP-119 would be located north of West Reserve
Drive. The existing topography does not provide a drainage way to convey storm water
from the pond to the natural conveyances. Outlet piping would be necessary for
detention ponds DP-118 and DP-119 to convey storm water along West Reserve Drive to
the Stillwater and Whitefish Rivers, respectively. The probable cost summary listed in
Table 4.4.2b-6 for these proposed conveyance outlet pipelines is based on the 100-year
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 4-15
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
peak discharge rate. Detailed cost estimates for the pipelines are included in the
Appendix of Facility Plan Update.
Table 4.4.2b-6: North Kalispell Conveyance Outlet Pipeline Probable
Cost Summary
Conveyance
Outlet
Pipeline
Pipeline
Length (feet)
Easement
Area (acres)
(See note 1)
100-year Peak
Dischage Rate
(cfs)
Pipe
Diameter
(inches)
Estimated
Conveyance
Pipeline Cost
Total Probable
Cost
COP-118 3,500 2.41 9.35 24 $3,275,000 $3,275,000
COP-119 1,500 1.03 6.73 24 $1,637,000 $1,637,000
Total 5,000 3.44 Total $4,912,000 $4,912,000
Note 1: Estimated easement based on 30 foot width.
4.4.2c West Stillwater Study Area
The West Stillwater catchment consists of the project study area northwest of the City of
Kalispell between the West Kalispell study area boundary and the Stillwater River. The
Spring Creek Road alignment is along the west boundary and Reserve Drive is on the
south boundary of the study area. The study area as shown in Figure 4.4.2c-1 is
approximately 4,312 acres or 6.7 square miles and consists of primarily agricultural crop
and pasture land with residential developments located adjacent to the Kalispell City
limits. The County Estates subdivision and Kalispell City Limits are located in southeast
corner of the study area.
The Stillwater River flows from north to south along the east boundary of the sub-area.
The FEMA Flood Insurance Study (FIS)13 has been completed on the Stillwater River
and includes detailed floodplain mapping from the north study area boundary to the City
of Kalispell.
13 Flood Insurance Study, Flathead County MT, Federal Emergency Management Agency (FEMA)
Community Number 300023, 1985.
4-16 City of Kalispell Storm Water Facility Plan Update March 28, 2008
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
4.4.2c.1 West Stillwater Storm Water Runoff Estimation and Critical
Drainage Way Identification
The West Stillwater study area was delineated into nine drainage basins based on the
topographic mapping from the City of Kalispell and USGS quadrangle mapping of the
study area. The hydraulic and hydrologic parameters of each drainage basin are shown
in Table 4.4.2c-1.
Table 4.4.2c-1: West Stillwater Catchment Drainage Basins
Area CN Y L S tL Tc Basin
ID (mi2) (acre) Existing Post (%) (ft) (-) (hrs) (hrs)
100 2.12 1357 64 70 2.74 20,422 5.702 3.379 5.632
101 0.43 272 65 72 1.48 8,754 5.313 2.240 3.734
113 0.63 405 65 73 5.11 3,602 5.348 0.594 0.991
114 0.78 499 64 71 4.23 7,551 5.527 1.204 2.007
115 0.21 136 64 70 8.14 2,195 5.539 0.324 0.539
124 0.66 421 64 72 4.10 8,000 5.617 1.293 2.155
140 0.59 380 63 71 3.30 6,619 5.898 1.276 2.126
141 0.91 584 64 69 5.25 3,039 5.526 0.522 0.870
142 0.41 262 64 72 6.03 3,010 5.554 0.485 0.808
Total 6.7 4312 Total 63,193
CN: SCS Runoff Curve Number
Y: Average Slope of watershead basin (%)
L: Length to basin divide or longest flow path (feet)
tL: Lag Time (hrs)
S: Potential maximum retention (unit less)
Tc: Time of concentration (hrs)
The results of the West Stillwater TR-20 computer modeling for the existing and post-
developed conditions in each of the nine drainage basins are shown in Table 4.4.2c-2 and
Table 4.4.2c-3, respectively. The differences between the existing and post-developed
100-year runoff estimation is shown in Table 4.4.2c-4.
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 4-17
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
Table 4.4.2c-2: West Stillwater Existing 100-year Runoff
Input Output
Basin Area Basin Area TC Qpeak Runoff Depth Runoff Volume Basin
(sq. miles) (acres) CN (hrs) (cfs) (inches) (acre-ft)
100 2.1 1,357 64 5.632 48.66 0.468 52.92
101 0.4 275 65 3.734 12.44 0.501 11.49
113 0.6 403 65 0.991 30.77 0.505 16.97
114 0.8 499 64 2.007 24.40 0.467 19.43
115 0.2 134 64 0.539 11.36 0.467 5.23
124 0.7 421 64 2.155 20.17 0.467 16.37
140 0.6 378 63 2.127 15.81 0.431 13.56
141 0.9 582 64 0.871 39.84 0.468 22.71
142 0.4 262 64 0.808 18.54 0.468 10.23
Total 6.7 4,312 Total 168.91
Table 4.4.2c-3: West Stillwater Post-Developed 100-year Runoff
Input Output
Basin Area Basin Area TC Qpeak Runoff Depth Runoff Volume Basin
(sq. miles) (acres) CN (hrs) (cfs) (inches) (acre-ft)
100 2.1 1,357 70 5.632 83.39 0.713 80.62
101 0.4 275 72 3.734 24.24 0.803 18.42
113 0.6 403 73 0.991 82.67 0.856 28.76
114 0.8 499 71 2.007 55.67 0.759 31.57
115 0.2 134 70 0.539 28.45 0.712 7.97
124 0.7 421 72 2.155 49.70 0.806 28.26
140 0.6 378 71 2.127 40.70 0.758 23.85
141 0.9 582 69 0.871 83.37 0.669 32.47
142 0.4 262 72 0.808 54.86 0.807 17.65
Total 6.7 4,312 Total 269.57
4-18 City of Kalispell Storm Water Facility Plan Update March 28, 2008
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
Table 4.4.2c-4: West Stillwater Difference in 100-year Runoff
Existing Post-Developed Difference
Q Runoff Volume Q Runoff Volume Q Runoff Volume Basin
(cfs) (acre-ft) (cfs) (acre-ft) (cfs) (acre-ft)
100* 48.66 52.92 83.39 80.62 34.73 27.70
101* 12.44 11.49 24.24 18.42 11.80 6.93
113** 30.77 16.97 82.67 28.76 51.90 11.79
114** 24.40 19.43 55.67 31.57 31.27 12.15
115** 11.36 5.23 28.45 7.97 17.09 2.74
124* 20.17 16.37 49.70 28.26 29.53 11.88
140 15.81 13.56 40.70 23.85 24.89 10.29
141 39.84 22.71 83.37 32.47 43.53 9.76
142 18.54 10.23 54.86 17.65 36.32 7.41
Total 168.91 Total 269.57 Total 100.65
* Basins with potential regional detention ponds.
** Closed basins.
4.4.2c.2 West Stillwater Study Area Storm Water Runoff Quantity Control
Recommendations
Based on the topography of the West Stillwater study area and existing drainage
conveyances, it is recommended that regional detention ponds be used to control post-
developed runoff in basins 100, 101 and 124 as shown in Figure 4.4.2c-1. In general, the
proposed regional detention ponds (DP) would be located along a major storm
conveyance and the outlet from the basin would discharge to the major conveyance. For
storage calculations, the 100-year, 24-hour storm would be used. The storm water
detention pond would be sized to store the difference between the existing and post-
development 100-year, 24-hour volume. A low-level outlet structure would be provided
with a discharge rate no greater than the 100-year peak for existing conditions. An
overflow spillway or structure would be provided to release the 100-year, 24-hour peak
discharge rate for the post-development condition.
The probable construction cost shown in Table 4.4.2c-5 for these proposed regional
detention ponds is based on the difference in 100-year volume and a maximum pond
depth of 3-feet. Detailed cost estimates for the ponds are included in the Appendix of
Facility Plan Update.
The topography of basins 113, 114 and 115 does not include major conveyances to
discharge storm water from the basin. These basins are closed basins (CB) and would not
have detention ponds with an outlet. In lieu of the detention pond facility it is proposed
that a drainage easement would be provided for the area at the low point of the basin to
pond and collect storm water. Closed basins could serve as enhanced or future wetlands
to mitigate existing wetland impacts and they could also provide storm water treatment
from future developments in the drainage basin. The probable construction cost listed in
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 4-19
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
Table 4.4.2c-5 for these proposed closed basins is based on the total 100-year post-
development volume and a maximum basin depth of 5-feet. Detailed cost estimates for
the basins are included in the Appendix of Facility Plan Update.
The capital improvement cost summary does not include the costs necessary to acquire
easements for the existing natural drainage ways. The City of Kalispell has indicated that
the preservation of these drainage ways would be completed through the planning and
permitting requirements of future developments in the drainage basin. Based on the TR-
20 analysis described in Section 4.2 and listed in Table 4.4.2c-1, the total length of
drainage ways from the basin divides to the outlet for the West Stillwater Study Area is
approximately 63,193 feet or 12 miles.
Table 4.4.2c-5: West Stillwater Facility Probable Cost Summary
Facility
ID
100 -year
Volume
(acre-ft)
Pond
Area
(acres)
100-year
Peak
Discharge
Rate (cfs)
Outlet Pipe
Diameter
(inches)
Estimated
Regional
DP Cost
Estimated
Closed Basin
Cost
Estimated
SWMP
Cost
Total
Probable Cost
DP-100A 13.85 4.6 48.66 42 $1,182,000 $0 $0 $1,182,000
DP-100B 13.85 4.6 24.33 36 $1,133,000 $0 $0 $1,133,000
DP-101 6.93 2.3 12.44 24 $613,000 $0 $0 $613,000
CB-113A-B 28.76 5.8 n/a n/a $0 $1,447,000 $0 $1,447,000
CB-114 31.57 6.3 n/a n/a $0 $1,588,000 $0 $1,588,000
CB-115 7.97 1.6 n/a n/a $0 $401,000 $0 $401,000
DP-124 11.88 4.0 20.17 36 $1,009,000 $0 $0 $1,009,000
SWMP-140 10.29 3.4 15.81 24 $0 $0 $824,000 $824,000
SWMP-141 9.76 3.3 39.84 42 $0 $0 $924,000 $924,000
SWMP-142 7.41 2.5 18.54 24 $0 $0 $643,000 $643,000
Total 142.27 38.3 Total $3,937,000 $3,436,000 $2,391,000 $9,764,000
DP: Proposed Regional Detention Pond with Outlet
CB: Proposed Regional Closed Basin with no Outlet
SWMP: Storm Water Management Ponds for Future Developments
Basins 140, 141 and 142 are located along the Stillwater River and do not have well-
established existing drainage conveyances and generally have a sheet flow runoff pattern
towards the river. Regional detention ponds are not feasible for these drainage basins.
Therefore, site specific storm water management ponds (SWMP) in these areas to control
the 100-year runoff would need to be incorporated into the design of the future
developments. The probable construction cost listed in Table 4.4.2c-5 for these storm
water management ponds are based on the 100-year volume and a maximum depth of 3-
feet. Detailed cost estimates for the ponds are included in the Appendix of Facility Plan
Update.
4-20 City of Kalispell Storm Water Facility Plan Update March 28, 2008
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
Proposed detention pond DP-124 would be located west of Stillwater Road and the
existing topography does not allow discharge to a major conveyance channel. Therefore,
outlet piping would be required to convey storm water south along Stillwater Road to a
major conveyance channel which is a tributary to Spring Creek. The probable cost
summary listed in Table 4.4.2c-6 for this proposed conveyance outlet pipeline is based on
the 100-year peak discharge rate. Detailed cost estimates for the pipeline is included in
the Appendix of Facility Plan Update.
Table 4.4.2c-6: West Stillwater Conveyance Outlet Pipeline Probable
Cost Summary
Conveyance
Pipeline
Pipeline Length
(feet)
Easement
Area (acres)
(See Note 1)
100-year
Peak
Dischage
Rate (cfs)
Pipe
Diameter
(inches)
Estimated
Conveyance
Pipeline Cost
Total
Probable
Cost
COP-124 3,300 2.27 20.17 36 $4,405,000 COP-124
Note 1: Estimated easement based on 30 foot width.
4.4.2d West Kalispell Study Area
The West Kalispell catchment consists of the project study area west of the City of
Kalispell. The Farm to Market Road alignment is on the west boundary and Ashley
Creek is on the south boundary of the study area. The study area as shown in Figure
4.4.2d-1 is approximately 12,426 acres or 19.4 square miles and consists of primarily
agricultural crop and pasture land with significant residential developments occurring
west of the Kalispell City limits.
Spring and Little Spring Creeks flow from northwest to southeast sections of the study
area to their confluence with Ashley Creek. Ashley Creek enters the study area from the
southwest and flows east to the confluence with the Flathead River. The FEMA Flood
Insurance Study (FIS) 14 has been completed on Spring, Little Spring and Ashley Creeks
and includes detailed floodplain mapping from the west study area boundary to the City
of Kalispell.
4.4.2d.1 West Kalispell Storm Water Runoff Estimation and Critical
Drainage Way Identification
The West Kalispell study area was delineated into fifteen drainage basins based on the
topographic mapping from the City of Kalispell and USGS quadrangle mapping of the
study area. The hydraulic and hydrologic parameters of each drainage basin are shown
in Table 4.4.2d-1.
14 Flood Insurance Study, Flathead County MT, Federal Emergency Management Agency (FEMA)
Community Number 300023, 1985.
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 4-21
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
Table 4.4.2d-1: West Kalispell Catchment Drainage Basins
Area CN Y L S tL Tc Basin
ID (mi2) (acre) Existing Post (%) (ft) (-) (hrs) (hrs)
110 2.14 1370 64 67 3.11 15,329 5.661 2.510 4.183
111 2.86 1830 64 73 3.52 14,700 5.560 2.257 3.762
112 0.72 461 62 70 5.71 7,586 6.147 1.109 1.849
122 0.97 621 64 75 2.55 7,333 5.542 1.517 2.528
123 2.59 1657 64 73 1.55 15,882 5.603 3.634 6.057
125 2.26 1446 63 69 12.71 21,619 5.801 1.659 2.765
126 1.59 1018 65 72 2.38 15,484 5.389 2.810 4.684
127 0.77 493 63 70 2.91 7,024 5.918 1.428 2.379
128 1.08 689 64 69 3.98 7,886 5.609 1.297 2.161
138 1.91 1222 63 65 14.23 15,535 5.923 1.219 2.031
139 0.84 538 62 63 11.08 7,427 6.044 0.775 1.291
147 0.61 390 67 74 5.12 1,277 4.997 0.249 0.415
148 0.45 288 66 74 5.57 1,303 5.078 0.245 0.408
158 0.35 224 72 78 2.11 4,635 3.942 0.950 1.584
159 0.28 179 66 73 7.59 1,604 5.083 0.248 0.413
Total 19.4 12,426 Total 144,626
CN: SCS Runoff Curve Number
Y: Average Slope of watershead basin (%)
L: Length to basin divide or longest flow path (feet)
tL: Lag Time (hrs)
S: Potential maximum retention (unit less)
Tc: Time of concentration (hrs)
The results of the West Kalispell TR-20 computer modeling for the existing and post-
developed conditions in each of the fifteen drainage basins are shown in Table 4.4.2d-2
and Table 4.4.2d-3, respectively. The differences between the existing and post-
developed 100-year runoff estimation is shown in Table 4.4.2d-4.
4-22 City of Kalispell Storm Water Facility Plan Update March 28, 2008
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
Table 4.4.2d-2: West Kalispell Existing 100-year Runoff
Input Output
Basin Area Basin Area TC Qpeak Runoff Depth Runoff Volume Basin
(sq. miles) (acres) CN (hrs) (cfs) (inches) (acre-ft)
110 2.1 1,370 64 4.183 53.82 0.468 53.41
111 2.9 1,830 64 3.835 73.70 0.468 71.39
112 0.7 461 64 1.965 22.69 0.467 17.93
122 1.0 621 64 2.531 28.18 0.467 24.16
123 2.6 1,657 64 6.057 58.09 0.468 64.62
125 2.3 1,446 63 2.765 56.76 0.432 52.07
126 1.6 1,018 65 4.684 42.71 0.505 42.82
127 0.8 493 63 2.381 20.04 0.431 17.70
128 1.1 689 64 3.352 32.98 0.468 26.88
138 1.9 1,222 63 2.031 51.82 0.432 44.01
139 0.8 538 62 1.291 22.23 0.398 17.83
147 0.6 390 67 0.415 63.74 0.585 19.03
148 0.5 288 66 0.408 40.46 0.544 13.06
158 0.4 224 72 1.584 31.57 0.805 15.03
159 0.3 179 66 0.413 25.00 0.544 8.12
Total 19.4 12,426 Total 488.06
Table 4.4.2d-3: West Kalispell Post-Developed 100-year Runoff
Input Output
Basin Area Basin Area TC Qpeak Runoff Depth Runoff Volume Basin
(sq. miles) (acres) CN (hrs) (cfs) (inches) (acre-ft)
110 2.1 1,370 67 4.183 72.97 0.584 66.65
111 2.9 1,830 71 3.835 146.07 0.760 115.93
112 0.7 461 73 1.965 62.80 0.856 32.87
122 1.0 621 74 2.531 79.62 0.907 46.92
123 2.6 1,657 73 6.057 124.29 0.856 118.19
125 2.3 1,446 69 2.765 111.87 0.669 80.64
126 1.6 1,018 72 4.684 80.13 0.807 68.43
127 0.8 493 70 2.381 45.41 0.712 29.24
128 1.1 689 69 2.161 60.18 0.669 38.43
138 1.9 1,222 65 2.031 68.11 0.506 51.54
139 0.8 538 63 1.291 26.46 0.432 19.35
147 0.6 390 74 0.415 143.70 0.908 29.54
148 0.5 288 74 0.408 107.17 0.907 21.77
158 0.4 226 78 1.584 52.43 1.126 21.20
159 0.3 176 73 0.413 60.46 0.856 12.57
Total 19.4 12,426 Total 753.27
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 4-23
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
Table 4.4.2d-4: West Kalispell Difference in 100-year Runoff
Existing Post-Developed Difference
Q Runoff Volume Q Runoff Volume Q Runoff Volume Basin
(cfs) (acre-ft) (cfs) (acre-ft) (cfs) (acre-ft)
110** 53.82 53.41 72.97 66.65 19.15 13.24
111** 73.70 71.39 146.07 115.93 72.37 44.54
112** 22.69 17.93 62.80 32.87 40.11 14.94
122* 28.18 24.16 79.62 46.92 51.44 22.76
123* 58.09 64.62 124.29 118.19 66.20 53.57
125* 56.76 52.07 111.87 80.64 55.11 28.57
126* 42.71 42.82 80.13 68.43 37.42 25.61
127* 20.04 17.70 45.41 29.24 25.37 11.54
128* 32.98 26.88 60.18 38.43 27.20 11.55
138* 51.82 44.01 68.11 51.54 16.29 7.54
139* 22.23 17.83 26.46 19.35 4.23 1.52
147 63.74 19.03 143.70 29.54 79.96 10.51
148 40.46 13.06 107.17 21.77 66.71 8.71
158* 31.57 15.03 52.43 21.20 20.86 6.17
159* 25.00 8.12 60.46 12.57 35.46 4.45
Total 488.06 Total 753.27 Total 265.21
* Basins with potential regional detention ponds.
** Closed basins.
4.4.2d.2 West Kalispell Study Area Storm Water Runoff Quantity Control
Recommendations
Based on the topography of the West Kalispell study area and existing drainage
conveyances, it is recommended that regional detention ponds be used to control post-
developed runoff in basins 122, 123, 125, 126, 127, 128, 138,139, 158 and 159 as shown
in Figure 4.4.2d-1. In general, the proposed regional detention ponds (DP) would be
located along a major storm conveyance and the outlet from the basin would discharge to
the major conveyance. For storage calculations, the 100-year, 24-hour storm would be
used. The storm water detention pond would be sized to store the difference between the
existing and post-development 100-year 24-hour volume. A low-level outlet structure
would be provided with a discharge rate no greater than the 100-year peak for existing
conditions. An overflow spillway or structure would be provided to release the 100-year,
24-hour peak discharge rate for the post-development condition.
The probable construction cost shown in Table 4.4.2d-5 for these proposed regional
detention ponds is based on the difference in 100-year volume and a maximum pond
depth of 3-feet. Detailed cost estimates for the ponds are included in the Appendix of
Facility Plan Update.
The topography of basins 110, 111 and 112 does not include major conveyances to
discharge storm water from the basin. These basins are closed basins (CB) and would not
4-24 City of Kalispell Storm Water Facility Plan Update March 28, 2008
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
have detention ponds with an outlet. In lieu of the detention pond facility it is proposed
that a drainage easement be provided for the area at the low point of the basin to pond and
collect storm water. Closed basins could serve as enhanced or future wetlands to mitigate
existing wetland impacts and they could also provide storm water treatment from future
developments in the drainage basin. The probable construction cost listed in Table
4.4.2d-5 for these proposed closed basins is based on the total 100-year post-development
volume and a maximum basin depth of 5-feet. Detailed cost estimates for the basins are
included in the Appendix of Facility Plan Update.
The capital improvement cost summary does not include the costs necessary to acquire
easements for the existing natural drainage ways. The City of Kalispell has indicated that
the preservation of these drainage ways would be completed through the planning and
permitting requirements of future developments in the drainage basin. Based on the TR-
20 analysis described in Section 4.2 and listed in Table 4.4.2d-1, the total length of
drainage ways from the basin divides to the outlet for the West Kalispell Study Area is
approximately 144,626 feet or 27.4 miles.
Table 4.4.2d-5: West Kalispell Facility Probable Cost Summary
Facility
ID
100 -year
Volume
(acre-ft)
Pond
Area
(acres)
100-year
Peak
Discharge
Rate (cfs)
Outlet
Pipe
Diameter
(inches)
Estimated
Regional
DP Cost
Estimated
Closed
Basin Cost
Estimated
SWMP
Cost
Total
Probable Cost
CB-110 66.65 13.3 n/a n/a $0 $3,354,000 $0 $3,354,000
CB-111 115.93 23.2 n/a n/a $0 $5,835,000 $0 $5,835,000
CB-112 32.87 6.6 n/a n/a $0 $1,654,000 $0 $1,654,000
DP-122 22.76 7.6 28.18 36 $1,693,000 $0 $0 $1,693,000
DP-123 53.57 17.9 58.09 48 $3,900,000 $0 $0 $3,900,000
DP-125 28.57 9.5 56.76 48 $2,329,000 $0 $0 $2,329,000
DP-126 25.61 8.5 42.71 42 $1,921,000 $0 $0 $1,921,000
DP-127 11.54 3.9 20.04 24 $903,000 $0 $0 $903,000
DP-128 11.55 3.9 32.98 48 $988,000 $0 $0 $988,000
DP-138 7.54 2.5 51.82 48 $1,007,000 $0 $0 $1,007,000
DP-139 1.52 0.5 22.23 36 $358,000 $0 $0 $358,000
SWMP-147 10.51 3.5 63.74 48 $0 $0 $1,194,000 $1,194,000
SWMP-148 8.71 2.9 40.46 42 $0 $0 $858,000 $858,000
DP-158 6.17 2.1 31.57 36 $690,000 $0 $0 $690,000
DP-159 4.45 1.5 25.00 36 $582,000 $0 $0 $582,000
Total 407.95 107.3 Total $14,371,000 $10,843,000 $2,052,000 $27,266,000
DP: Proposed Regional Detention Pond with Outlet
CB: Proposed Regional Closed Basin with no Outlet
SWMP: Storm Water Management Ponds for Future Developments
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 4-25
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
Basins 147 and 148 are located along the Ashley Creek and do not have well-established
existing drainage conveyances and generally have a sheet flow runoff pattern towards the
river. Regional detention ponds are not feasible for these drainage basins. Therefore, site
specific storm water management ponds (SWMP) in these areas to control the 100-year
runoff would need to be incorporated into the design of the future developments. The
probable cost summary listed in Table 4.4.2d-5 for these storm water management ponds
are based on the 100-year volume and a maximum depth of 3-feet. Detailed cost
estimates for the ponds are included in the Appendix of Facility Plan Update.
4.4.2e East Kalispell Study Area
The East Kalispell catchment consists of the project study area east of the City of
Kalispell. U.S. Highway 93 alignment is on the west boundary and Willow Glen Road
alignment is on the east boundary of the study area. The study area as shown in Figure
4.4.2e-1 is approximately 634 acres or 0.99 square miles and consists of primarily urban
developed subdivisions on the southeast Kalispell City limits.
The Flathead River flows from north to south along the east study area boundary. The
FEMA Flood Insurance Study (FIS) 15 detailed floodplain mapping has been completed
on the Flathead River along the east study area boundary of the City of Kalispell.
4.4.2e.1 East Kalispell Storm Water Runoff Estimation and Critical
Drainage Way Identification
The East Kalispell study area was delineated into one drainage basin based on the
topographic mapping from the City of Kalispell and USGS quadrangle mapping of the
study area. The hydraulic and hydrologic parameters of the drainage basin are shown in
Table 4.4.2e-1.
Table 4.4.2e-1: East Kalispell Catchment Drainage Basins
Area CN Y L S tL Tc Basin
ID (mi2) (acre) Existing Post (%) (ft) (-) (hrs) (hrs)
132 0.99 634 72 76 2.81 12,930 3.935 1.869 3.115
Total 0.99 634 Total 12,930
CN: SCS Runoff Curve Number
Y: Average Slope of watershead basin (%)
L: Length to basin divide or longest flow path (feet)
tL: Lag Time (hrs)
S: Potential maximum retention (unit less)
Tc: Time of concentration (hrs)
15 Flood Insurance Study, Flathead County MT, Federal Emergency Management Agency (FEMA)
Community Number 300023, 1985.
4-26 City of Kalispell Storm Water Facility Plan Update March 28, 2008
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
The results of the East Kalispell TR-20 computer modeling for the existing and post-
developed conditions in the drainage basin are indicated in Table 4.4.2e-2 and Table
4.4.2e-3, respectively. The differences between the existing and post-developed 100-
year runoff estimation is shown in Table 4.4.2e-4.
Table 4.4.2e-2: East Kalispell Existing 100-year Runoff
Input Output
Basin Area Basin Area TC Qpeak Runoff Depth Runoff Volume Basin
(sq. miles) (acres) CN (hrs) (cfs) (inches) (acre-ft)
132 0.99 634 72 2.999 62.38 0.807 42.61
Total 0.99 634 Total 42.61
Table 4.4.2e-3: East Kalispell Post-Developed 100-year Runoff
Input Output
Basin Area Basin Area TC Qpeak Runoff Depth Runoff VolumeBasin
(sq. miles) (acres) CN (hrs) (cfs) (inches) (acre-ft)
132 0.99 634 76 2.999 86.60 1.013 53.49
Total 0.99 634 Total 53.49
Table 4.4.2e-4: East Kalispell Difference in 100-year Runoff
Existing Post-Developed Difference
Q Runoff Volume Q Runoff Volume Q Runoff Volume Basin
(cfs) (acre-ft) (cfs) (acre-ft) (cfs) (acre-ft)
132 62.38 42.61 86.60 53.49 24.22 10.88
Total 42.61 Total 53.49 Total 10.88
4.4.2e.2 East Kalispell Study Area Storm Water Runoff Quantity Control
Recommendations
Based on the topography of the East Kalispell study area and existing drainage
conveyances, it is recommended that a regional detention pond be used to control post-
developed runoff for basin 132 as shown in Figure 4.4.2e-1. In general, the proposed
regional detention pond (DP) would be located along a major storm conveyance and the
outlet from the basin would discharge to the major conveyance. For storage calculation,
the 100-year, 24-hour storm would be used. The storm water detention pond would be
sized to store the difference between the existing and post-development 100-year 24-hour
volume. A low-level outlet structure would be provided with a discharge rate no greater
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 4-27
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
than the 100-year peak for existing conditions. An overflow spillway or structure would
be provided to release the 100-year, 24-hour peak discharge rate for the post-development
condition. Because of the existing level of development in basin 132, potential detention
pond locations are limited. Topography also limits the potential locations for a detention
pond facility.
The probable construction cost shown in Table 4.4.2e-5 for this proposed regional
detention pond is based on the difference in 100-year volume and a maximum pond depth
of 3-feet. The detailed cost estimate for the pond is included in the Appendix of Facility
Plan Update.
The capital improvement cost summary does not include the costs necessary to acquire
easements for the existing natural drainage ways. The City of Kalispell has indicated that
the preservation of these drainage ways would be completed through the planning and
permitting requirements of future developments in the drainage basin. Based on the TR-
20 analysis described in Section 4.2 and listed in Table 4.4.2e-1, the total length of
drainage ways from the basin divides to the outlet for the East Kalispell Study Area is
approximately 12,930 feet or 2.45 miles.
Table 4.4.2e-5: East Kalispell Facility Probable Cost Summary
Facility
ID
100 -year
Volume
(acre-ft)
Pond Area
(acres)
100-year
Peak
Discharge
Rate (cfs)
Outlet Pipe
Diameter
(inches)
Proposed
Regional Pond
Probable Cost
Total Probable
Cost
DP-132 10.88 3.6 62.38 48 $1,217,000 $1,217,000
Total 10.88 3.6 Total $1,217,000 $1,217,000
DP: Proposed Regional Detention Pond with Outlet
4.4.2f South Kalispell Study Area
The South Kalispell catchment consists of the project study area south of the City of
Kalispell. U.S. Highway 93 alignment passes through the study area. The study area as
shown in Figure 4.4.2f-1 is approximately 7,686 acres or 12 square miles and consists of
primarily urban developed subdivisions south of the Kalispell City limits.
The Flathead River flows from north to south along the east study area boundary. The
FEMA Flood Insurance Study (FIS) 16 detailed floodplain mapping has been completed
on the Flathead River along the east study area boundary of the City of Kalispell.
16 Flood Insurance Study, Flathead County MT, Federal Emergency Management Agency (FEMA)
Community Number 300023, 1985.
4-28 City of Kalispell Storm Water Facility Plan Update March 28, 2008
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
4.4.2f.1 South Kalispell Storm Water Runoff Estimation and Critical
Drainage Way Identification
The South Kalispell study area was delineated into twelve drainage basins based on the
topographic mapping from the City of Kalispell and USGS quadrangle mapping of the
study area. The hydraulic and hydrologic parameters of each drainage basin are shown
in Table 4.4.2f-1.
Table 4.4.2f-1: South Kalispell Catchment Drainage Basins
Area CN Y L S tL Tc Basin
ID (ft2) (mi2) (acre) Existing Post (%) (ft) (-) (hrs) (hrs)
130 41,525,990 1.5 953 68 70 16.66 9,502 4.782 0.670 1.117
131 29,206,454 1.0 670 68 73 0.96 5,363 4.796 1.773 2.956
133 32,842,790 1.2 754 65 67 18.14 4,907 5.401 0.406 0.677
134 22,302,003 0.8 512 69 74 4.50 4,488 4.464 0.680 1.133
135 11,998,998 0.4 275 67 73 0.60 4,545 4.993 2.005 3.342
136 75,873,394 2.7 1,742 65 69 13.48 7,641 5.271 0.662 1.104
137 40,640,104 1.5 933 66 72 0.91 8,370 5.065 2.682 4.470
149 8,417,622 0.3 193 67 71 1.03 1,404 4.868 0.590 0.983
150 16,628,316 0.6 382 72 73 2.31 3,293 3.905 0.687 1.145
154 9,566,149 0.3 220 64 71 0.77 4,368 5.507 1.820 3.033
155 19,320,751 0.7 444 67 74 0.29 3,892 4.816 2.496 4.159
156 26,371,447 0.9 605 67 71 1.29 12,164 4.833 2.955 4.925
Total 334,694,018 12.0 7,686 Total 69,937
CN: SCS Runoff Curve Number
Y: Average Slope of watershead basin (%)
L: Length to basin divide or longest flow path (feet)
tL: Lag Time (hrs)
S: Potential maximum retention (unit less)
Tc: Time of concentration (hrs)
The results of the South Kalispell TR-20 computer modeling for the existing and post-
developed conditions in each of the twelve drainage basins are shown in Table 4.4.2f-2
and Table 4.4.2f-3, respectively. The differences between the existing and post-
developed 100-year runoff estimation is shown in Table 4.4.2f-4.
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 4-29
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
Table 4.4.2f-2: South Kalispell Existing 100-year Runoff
Input Output
Basin Area Basin Area TC Qpeak Runoff Depth Runoff Volume Basin
(sq. miles) (acres) CN (hrs) (cfs) (inches) (acre-ft)
130 1.5 954 68 1.117 104.89 0.626 49.75
131 1.1 672 68 2.956 45.53 0.625 35.00
133 1.2 755 65 0.677 68.91 0.506 31.84
134 0.8 512 69 1.133 63.26 0.669 28.54
135 0.4 275 67 3.343 16.00 0.580 13.30
136 2.7 1,741 65 1.107 126.27 0.506 73.40
137 1.5 934 66 4.489 43.94 0.543 42.28
149 0.3 192 67 0.983 19.79 0.583 9.33
150 0.6 384 72 1.145 65.61 0.807 25.82
154 0.3 218 64 3.033 9.37 0.464 8.41
155 0.7 442 67 4.159 23.58 0.582 21.42
156 1.0 608 67 4.925 30.39 0.582 29.49
Total 12.0 7,686 Total 368.59
Table 4.4.2f-3: South Kalispell Post-Development 100-year Runoff
Input Output
Basin Area Basin Area TC Qpeak Runoff Depth Runoff Volume Basin
(sq. miles) (acres) CN (hrs) (cfs) (inches) (acre-ft)
130 1.5 954 70 1.117 133.44 0.714 56.74
131 1.1 672 73 2.956 72.76 0.856 47.94
133 1.2 755 67 0.677 94.63 0.585 36.82
134 0.8 512 74 1.133 106.31 0.907 38.70
135 0.4 275 73 3.343 27.87 0.853 19.56
136 2.7 1,741 69 1.107 217.89 0.669 97.05
137 1.5 934 71 4.489 69.43 0.759 59.10
149 0.3 192 71 0.983 32.27 0.758 12.13
150 0.6 384 73 1.145 72.31 0.856 27.39
154 0.3 218 71 3.033 19.50 0.755 13.69
155 0.7 442 74 4.159 43.24 0.905 33.30
156 1.0 608 71 4.925 43.30 0.758 38.41
Total 12.0 7,686 Total 480.82
4-30 City of Kalispell Storm Water Facility Plan Update March 28, 2008
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
Table 4.4.2f-4: South Kalispell Difference in 100-year Runoff
Existing Post-Developed Difference
Q Runoff Volume Q Runoff Volume Q Runoff Volume Basin
(cfs) (acre-ft) (cfs) (acre-ft) (cfs) (acre-ft)
130* 104.89 49.75 133.44 56.74 28.55 6.99
131* 45.53 35.00 72.76 47.94 27.23 12.94
133* 68.91 31.84 94.63 36.82 25.72 4.97
134* 63.26 28.54 106.31 38.70 43.05 10.15
135* 16.00 13.30 27.87 19.56 11.87 6.26
136** 126.27 73.40 217.89 97.05 91.62 23.65
137** 43.94 42.28 69.43 59.10 25.49 16.82
149 19.79 9.33 32.27 12.13 12.48 2.80
150 65.61 25.82 72.31 27.39 6.70 1.57
154 9.37 8.41 19.50 13.69 10.13 5.28
155 23.58 21.42 43.24 33.30 19.66 11.89
156** 30.39 29.49 43.30 38.41 12.91 8.92
Total 368.59 Total 480.82 Total 112.23
* Basins with potential regional detention ponds.
** Closed basins.
4.4.2f.2 South Kalispell Study Area Storm Water Runoff Quantity Control
Recommendations
Based on the topography of the South Kalispell study area and existing drainage
conveyances, it is recommended that a regional detention ponds be used to control post-
developed runoff in basins 130, 131, 133, 134 and 135 as shown in Figure 4.4.2f-1. In
general, the proposed regional detention ponds (DP) would be located along a major
storm water conveyance and the outlet would discharge to the conveyance. For storage
calculations, the 100-year, 24-hour storm would be used. The storm water detention
pond would be sized to store the difference between the existing and post-development
100-year, 24-hour volume. A low-level outlet structure would be provided with a
discharge rate no greater than the 100-year peak for existing conditions. An overflow
spillway or structure would be provided to release the 100-year, 24-hour peak discharge
rate for the post-development condition.
The probable construction cost shown in Table 4.4.2f-5 for these proposed regional
detention ponds is based on the difference in 100-year volume and a maximum depth of
3-feet. Detailed cost estimates for the ponds are included in the Appendix of Facility
Plan Update.
The topography of basins 136, 137 and 156 does not include major conveyances that can
be used to discharge storm water from the basin. These basins are closed basins (CB) and
would not have detention ponds with an outlet. In lieu of the detention pond facility it is
proposed that a drainage easement be provided for the area at the low point of the basin to
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 4-31
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
pond and collect storm water. These basins could serve as enhanced or future wetlands to
mitigate existing wetland impacts and they could also provide storm water treatment from
future developments in the drainage basin. The probable construction cost listed in Table
4.4.2f-5 for these proposed closed basins is based on the total 100-year post-development
volume and a maximum basin depth of 5-feet. Detailed cost estimates for the basins are
included in the Appendix of Facility Plan Update.
The capital improvement cost summary does not include the costs necessary to acquire
easements for the existing natural drainage ways. The City of Kalispell has indicated that
the preservation of these drainage ways would be completed through the planning and
permitting requirements of future developments in the drainage basin. Based on the TR-
20 analysis described in Section 4.2 and listed in Table 4.4.2f-1, the total length of
drainage ways from the basin divides to the outlet for the South Kalispell Study Area is
approximately 69,937 feet or 13.25 miles.
Table 4.4.2f-5: South Kalispell Facility Probable Cost Summary
Facility
ID
100 -
year
Volume
(acre-
ft)
Pond
Area
(acres)
100-year
Peak
Discharge
Rate (cfs)
Outlet Pipe
Diameter
(inches)
Estimated
Regional
DP Cost
Estimated
Closed Basin
Cost
Estimated
SWMP
Cost
Total
Probable Cost
DP-130 6.99 2.3 104.89 60 $1,417,000 $0 $0 $1,417,000
DP-131 12.94 4.3 45.53 42 $1,124,000 $0 $0 $1,124,000
DP-133 4.97 1.7 68.91 48 $846,000 $0 $0 $846,000
DP-134 10.15 3.4 63.26 48 $1,171,000 $0 $0 $1,171,000
DP-135 6.26 2.1 16.00 24 $572,000 $0 $0 $572,000
CB-136A/B 97.05 19.4 n/a n/a $0 $4,884,000 $0 $4,884,000
CB-137 59.10 11.8 n/a n/a $0 $2,974,000 $0 $2,974,000
SWMP-149 2.80 0.9 19.79 24 $0 $0 $353,000 $353,000
SWMP-150 1.57 0.5 65.61 48 $0 $0 $632,000 $632,000
SWMP-154 5.28 1.8 9.37 24 $0 $0 $510,000 $510,000
SWMP-155 11.89 4.0 23.58 36 $0 $0 $1,018,000 $1,018,000
CB-156 38.41 7.7 n/a n/a $0 $1,933,000 $0 $1,933,000
Total 257.41 59.9 Total $5,130,000 $9,791,000 $2,513,000 $17,434,000
DP: Proposed Regional Detention Pond with Outlet
CB: Proposed Regional Closed Basin with no Outlet
SWMP: Storm Water Management Ponds for Future Developments
Basins 149, 150, 154 and 155 are located along Ashley Creek and the Flathead River.
These basins do not have well established existing drainage conveyances and generally
have a sheet flow runoff pattern towards the creek and river. Regional detention ponds
are not feasible for these drainage basins. Therefore, site-specific storm water
4-32 City of Kalispell Storm Water Facility Plan Update March 28, 2008
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 4-33
management ponds (SWMP) to control the 100-year runoff would need to be
incorporated into the design of future developments. The probable cost summary listed
in Table 5.4.2f-5 for these storm water management ponds are based on the 100-year
volume and a maximum depth of 3-feet. Detailed cost estimates for the ponds are
included in the Appendix of Facility Plan Update.
4.4.3 Storm Water Collection, Detention and Discharge System
Expansion Analysis Probable Cost Summary
This section of the Facility Plan summarizes the Storm Water Capital Improvements
probable costs estimates for the for the 62.6 square miles or 40,429 acres study area
including: a) East Whitefish River, b) North Kalispell, c) West Stillwater River, d) West
Kalispell, e) East Kalispell and f) South Kalispell as shown in Figure 4.2-1.
The probable cost summary for the storm water ponds is summarized in Table 4.4.3-1. A
total of 36 regional detention ponds, 10 regional closed basins, and 16 drainage basins
with storm water management ponds to be included as part of future developments are
listed in the Table 4.4.3-1. The probable cost summary for the regional detention ponds
(DP) and Storm Water Management Ponds (SWMP) are based on the difference in runoff
between existing and post-developed conditions of the 100-year 24-hour volume and a
maximum depth of 3-feet. The probable cost summaries for the closed basins (CB) are
based on the total post-developed 100-year 24-hour runoff and a maximum depth of 5-
feet.
Three of the proposed detention pond outlets would be located adjacent to existing roads
or upstream of existing developments and do not have access to major drainage ways to
discharge storm water from the ponds to downstream conveyances. Outlet piping would
be required for these detention ponds and the probable cost summary for these proposed
conveyance outlet pipelines is summarized in Table 4.4.3-2.
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
Table 4.4.3-1: Storm Water Pond Capital Improvement Summary
Pond ID
100 -year
Volume
(acre-ft)
Pond Area
(acres)
100-year Peak
Discharge Rate
(cfs)
Outlet Pipe
Diameter
(inches)
Estimated
DP Cost
Estimated
CB Cost
Estimated
SWMP Cost
Total
Estimate Cost
DP-100A 13.85 4.6 48.66 42 $1,182,000 $0 $0 $1,182,000
DP-100B 13.85 4.6 24.33 36 $1,133,000 $0 $0 $1,133,000
DP-101 6.93 2.3 12.44 24 $613,000 $0 $0 $613,000
DP-102 5.51 1.8 56.88 48 $880,000 $0 $0 $880,000
DP-103 21.72 7.2 54.22 48 $1,898,000 $0 $0 $1,898,000
DP-104 14.28 4.8 9.08 18 $1,066,000 $0 $0 $1,066,000
DP-105 15.16 5.1 6.95 18 $1,112,000 $0 $0 $1,112,000
DP-106 4.21 1.4 9.89 24 $442,000 $0 $0 $442,000
DP-107 1.43 0.5 16.08 24 $268,000 $0 $0 $268,000
DP-108 24.98 8.3 39.94 42 $1,881,000 $0 $0 $1,881,000
DP-109 13.19 4.4 17.98 36 $1,091,000 $0 $0 $1,091,000
CB-110 66.65 13.3 n/a n/a $0 $3,354,000 $0 $3,354,000
CB-111 115.93 23.2 n/a n/a $0 $5,835,000 $0 $5,835,000
CB-112 32.87 6.6 n/a n/a $0 $1,654,000 $0 $1,654,000
CB-113A-B 28.76 5.8 n/a n/a $0 $1,447,000 $0 $1,447,000
CB-114 31.57 6.3 n/a n/a $0 $1,588,000 $0 $1,588,000
CB-115 7.97 1.6 n/a n/a $0 $401,000 $0 $401,000
DP-116 2.24 0.8 6.63 18 $301,000 $0 $0 $301,000
4-34 City of Kalispell Storm Water Facility Plan Update
March 28, 2008April 16, 2008
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
Pond ID
100 -year
Volume
(acre-ft)
Pond Area
(acres)
100-year Peak
Discharge Rate
(cfs)
Outlet Pipe
Diameter
Estimated Estimated Estimated Total
DP Cost CB Cost SWMP Cost Estimate Cost (inches)
DP-117 2.81 0.9 6.07 18 $337,000 $0 $0 $337,000
DP-118 9.88 3.3 9.35 24 $798,000 $0 $0 $798,000
DP-119 7.95 2.7 6.73 18 $660,000 $0 $0 $660,000
DP-120 13.24 4.4 10.58 24 $1,010,000 $0 $0 $1,010,000
DP-121 7.35 2.5 16.26 24 $640,000 $0 $0 $640,000
DP-122 22.76 7.6 28.18 36 $1,693,000 $0 $0 $1,693,000
DP-123 53.57 17.9 58.09 48 $3,900,000 $0 $0 $3,900,000
DP-124 11.88 4.0 20.17 36 $1,009,000 $0 $0 $1,009,000
DP-125 28.57 9.5 56.76 48 $2,329,000 $0 $0 $2,329,000
DP-126 25.61 8.5 42.71 42 $1,921,000 $0 $0 $1,921,000
DP-127 11.54 3.9 20.04 24 $903,000 $0 $0 $903,000
DP-128 11.55 3.9 32.98 48 $988,000 $0 $0 $988,000
DP-129 16.58 5.5 100.46 60 $2,020,000 $0 $0 $2,020,000
DP-130 6.99 2.3 104.89 60 $1,417,000 $0 $0 $1,417,000
DP-131 12.94 4.3 45.53 42 $1,124,000 $0 $0 $1,124,000
DP-132 10.88 3.6 62.38 48 $1,217,000 $0 $0 $1,217,000
DP-133 4.97 1.7 68.91 48 $846,000 $0 $0 $846,000
DP-134 10.15 3.4 63.26 48 $1,171,000 $0 $0 $1,171,000
DP-135 6.26 2.1 16.00 24 $572,000 $0 $0 $572,000
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 4-35
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
Pond ID
100 -year
Volume
(acre-ft)
Pond Area
(acres)
100-year Peak
Discharge Rate
(cfs)
Outlet Pipe
Diameter
Estimated Estimated Estimated Total
DP Cost CB Cost SWMP Cost Estimate Cost (inches)
CB-136 97.05 19.4 n/a n/a $0 $4,884,000 $0 $4,884,000
CB-137 59.10 11.8 n/a n/a $0 $2,974,000 $0 $2,974,000
DP-138 7.54 2.5 51.82 48 $1,007,000 $0 $0 $1,007,000
DP-139 1.52 0.5 22.23 36 $358,000 $0 $0 $358,000
SWMP -140 10.29 3.4 15.81 24 $0 $0 $824,000 $824,000
SWMP -141 9.76 3.3 39.84 42 $0 $0 $924,000 $924,000
SWMP -142 7.41 2.5 18.54 24 $0 $0 $643,000 $643,000
SWMP -143 5.71 1.9 31.19 36 $0 $0 $621,000 $621,000
SWMP -144 9.22 3.1 18.44 24 $0 $0 $757,000 $757,000
SWMP -145 6.86 2.3 9.82 18 $0 $0 $591,000 $591,000
SWMP -146 7.35 2.5 26.59 36 $0 $0 $724,000 $724,000
SWMP -147 10.51 3.5 63.74 48 $0 $0 $1,194,000 $1,194,000
SWMP -148 8.71 2.9 40.46 42 $0 $0 $858,000 $858,000
SWMP -149 2.80 0.9 19.79 24 $0 $0 $353,000 $353,000
SWMP -150 1.57 0.5 65.61 48 $0 $0 $632,000 $632,000
SWMP -151 6.57 2.2 10.96 24 $0 $0 $591,000 $591,000
SWMP -152 3.38 1.1 13.73 24 $0 $0 $391,000 $391,000
SWMP -153 21.18 7.1 34.33 36 $0 $0 $1,593,000 $1,593,000
SWMP-154 5.28 1.8 9.37 24 $0 $0 $510,000 $510,000
4-36 City of Kalispell Storm Water Facility Plan Update
March 28, 2008April 16, 2008
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 4-37
Pond ID
100 -year
Volume
(acre-ft)
Pond Area
(acres)
100-year Peak
Discharge Rate
(cfs)
Outlet Pipe
Diameter
(inches)
Estimated
DP Cost
Estimated
CB Cost
Estimated
SWMP Cost
Total
Estimate Cost
SWMP -155 11.89 4.0 23.58 36 $0 $0 $1,018,000 $1,018,000
CB-156 38.41 7.7 n/a n/a $0 $1,933,000 $0 $1,933,000
DP-157 2.62 0.9 38.55 42 $467,000 $0 $0 $467,000
DP-158 6.17 2.1 31.57 36 $690,000 $0 $0 $690,000
DP-159 4.45 1.5 25.00 36 $582,000 $0 $0 $582,000
Total 1041.93 283.5 Total $39,526,000 $24,070,000 $12,224,000 $75,820,000
DP: Proposed Regional Detention Pond with Outlet
CB: Proposed Regional Closed Basin with no Outlet
SWMP: Storm Water Management Ponds for Future Developments
4.0 Storm Water Major Conveyance, Detention and Discharge Analysis
Table 4.4.3-2: Storm Water Conveyance Outlet Pipeline
Capital Improvement Summary
Conveyance
Outlet
Pipeline
Pipeline
Length
(feet)
Easement
Area
(acres)
100-year
Peak
Dischage
Rate (cfs)
Pipe
Diameter
(inches)
Total
Estimated
Cost
COP-118 3,500 2.41 9.35 24 $3,275,000
COP-119 1,500 1.03 6.73 24 $1,637,000
COP-124 3,300 2.27 20.17 36 $4,405,000
Total 8,300 5.71 Total $9,317,000
Table 4.4.3-3: Storm Water Capital Improvement Summary
Facility Total Estimated Cost
Detention Pond (DP) $39,526,000
Closed Basin (CB) $24,070,000
Storm Water Management Pond (SWMP) $12,224,000
Conveyance Outlet Pipeline (COP) $9,317,000
Total $85,137,000
4-38 City of Kalispell Storm Water Facility Plan Update
5.0 Recommendations and Capital Improvements Plan
5.0 Recommendations and Capital Improvements Plan
5.1 Introduction
This section of the Facility Plan summarizes the Capital Improvements recommended in
the City of Kalispell 2007 Storm Water Facility Plan Update. Recommendations include
the program prioritization and design guidelines for the regional detention ponds, closed
basins, and conveyance outlet pipelines storm water facilities. This section of the facility
plan also estimates the cost of recommended improvements and discusses growth versus
renewal and replacement costs associated with recommended capital projects.
5.2 Capital Improvement Program Prioritization
The storm water capital improvements listed in Tables 4.4.3-1 and Table 4.4.3-2 would
be prioritized based on the growth rate and location of future developments in the study
area. The initial step for the City of Kalispell and Flathead County would be to develop a
prioritization plan for the storm water infrastructure recommended in the 2007 Storm
Water Facility Plan Update. This step would include developing a funding plan to
acquire the properties for the planning and construction of the regional detention ponds
(DP) and the perpetuation of the closed basins (CB).
Table 5.2-1 is a summary of the number of proposed regional DP and CB for each study
sub-area in the Storm Water Facility Plan Update. Prioritization of property acquisition
for regional DP closer to the City Limits or where there is known development activity is
recommended since initial future developments will more likely occur closer to the City
Limits and/or these areas first and then progress further away.
Table 5.2-1 also summarizes the number of drainage basins that would require storm
water management ponds (SWMP) in each study sub-area. These ponds would be
incorporated into the design of future developments since the basins do not have well
established existing drainage conveyances and generally have a sheet flow runoff pattern
towards a creek or river. Therefore, site-specific SWMP to control the 100-year runoff
would be required for future developments in these basins.
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 5-1
5.0 Recommendations and Capital Improvements Plan
Table 5.2-1: Detention Pond, Closed Basin and SWMP Summary
Study Sub-Area
Detention
Ponds
(DP)
Closed
Basins
(CB)
Drainage Basins with Storm Water
Management Ponds
(SWMP)
East Whitefish River 6 0 4
North Kalispell 9 0 3
West Stillwater River 4 3 3
West Kalispell 10 3 2
East Kalispell 1 0 0
South Kalispell 5 3 4
Total 35 9 16
As noted in Section 4 of the 2007 Storm Water Facility Plan Update, the capital
improvement costs to acquire the properties for the existing natural drainage ways was
not included in the construction cost estimates since the City plans to preserve these
drainage ways as part of the planning and permitting phases of future developments. It is
important that the City and County preserve these existing drainage ways since they serve
as the primary storm water conveyances for the study area. Existing drainage ways will
become more significant as storm water runoff volumes and rates increase as future
development occurs in the study area.
5.3 Capital Improvement Recommendations
5.3.1 Regional Detention Ponds (DP) Facilities:
The principal storm water management facility that the 2007 Storm Water Facility Plan
Update recommends are the regional detention pond facilities. These facilities offer an
economic benefit to storm water management since they also provide a best management
practice (BMP) for water quality and quantity benefits.
Benefits of regional detention ponds include:
Focused application for water quality protection and fewer smaller ponds for
city staff to maintain and manage.
The City is responsible for the design of the ponds so water quality and
quantity will benefit the City.
Reduces the design review of future developments for the City since the
regional detention ponds will be built and function in accordance with City
standards and requirements.
5-2 City of Kalispell Storm Water Facility Plan Update March 28, 2008
5.0 Recommendations and Capital Improvements Plan
Larger ponds are more efficient at providing storage volumes per area of
land versus several smaller ponds that provide the same total storage
volume.
Detention ponds are an effective approach for dealing with urban
redevelopment where best management practices (BMPs) are not available
or limited.
Drawbacks of regional detention ponds include:
Regional ponds require one larger land area that might not be available in
some situations.
Regional ponds may present a potential hazard or liability concern.
Reduced flexibility for dealing with site specific water quality issues related
to a specific development or regional detention pond site.
City will likely front a good portion of the initial cost burden for
development of regional ponds in order for upstream developments to
proceed.
Potential for degradation of open channels and riparian systems between
regional ponds, particularly in the upper headwaters due to increased urban
runoff volumes.
Majority of regional ponds will more likely become in-stream channel ponds
versus off-stream ponds which may limit design options for water quality
protection.
City may need to develop a policy to credit back developments that will
need to develop their site specific Storm Water Management Ponds
(SWMP) since they will not use regional ponds.
5.3.2 Detention Pond (DP) and Storm Water Management Pond (SWMP)
Facility Design Guidelines:
The recommended typical regional detention pond (DP) and Storm Water Management
Pond (SWMP) facility design schematic is shown in Figure 5.3-1. As the schematic
shows, the DP and SWMP would range in depth from 3 to 5 feet and have a wedge shape
with a minimum length to width ratio of 1.5:1. This shape provides a more effective
distance for suspended solids to settling out into the pond prior to discharging. A
minimum 4 horizontal to 1 vertical slope would be provided around the inside perimeter
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 5-3
5.0 Recommendations and Capital Improvements Plan
of the pond from the high water mark for safety and access into and out of the pond.
Additionally, a low-flow channel would be graded through the pond bottom to convey
storm water through the ponds and to the outlet structure.
The pond outlet structure would have a principal spillway with the overall capacity sized
to discharge the post-developed storm event with release rates through the outlet limited
to the 100-year existing peak discharge rate. Additional orifices or outlets in the riser
would be sized to limit the 10-year and 50-year post-developed storm event peak
discharge rates to the respective existing storm peak discharge rates. The low-level
orifice would be sized for routing of the 2-year post-developed storm event with a release
rate limited to the 2-year existing storm event. The outlet would have a rip-rip lined
stilling basin to provide for scour protection at the outfall.
Design of the dam embankment would include a geotechnical evaluation to ensure that
the soils and embankment design would be stable to handle a rapid rise of water level and
drain down after a storm event. To provide vehicular access across the embankment, a
minimum 12-foot wide top width would be provided and the side slopes would be at a 3
horizontal to 1 vertical slope. An emergency spillway with 3-foot freeboard would be
provided to protect the embankment from overtopping during a flood event or if the
outlet structure became plugged or unusable.
It is recommended that a mimum12-foot wide access road be provided to the pond for the
maintenance and removal of sediment deposition. Sediment may need to be removed
after flood events to maintain the required capacity of the pond.
5.3.3 Regional Facility Volume Management:
Since the detention facility volumes are critical for routing post-development flood
events, it is recommended that the City of Kalispell develop a storm water accounting
procedure to track and manage the pond and basin volumes for each study sub-area.
Table 5.3-1 is an example of a table format that could be used to track pond volumes in
the West Kalispell study area. The required, existing, and planned future volumes for
each facility within the study area would be tracked to establish existing and future
balances. A computerized spreadsheet for each of the six study sub-areas including: a)
East Whitefish River, b) North Kalispell, c) West Stillwater River, d) West Kalispell, e)
East Kalispell and f) South Kalispell would allow for the facility capacities to be updated
before/after construction and as part of future City of Kalispell planning efforts.
5-4 City of Kalispell Storm Water Facility Plan Update March 28, 2008
5.0 Recommendations and Capital Improvements Plan
Table 5.3-1: Example West Kalispell Facility Volume Summary
Facility
ID
Required
Volume
(acre-ft)
Existing
Volume
(acre-ft)
Future Volume
(acre-ft)
Existing Balance
Credit (+), Debit (-)
Future Balance
Credit (+), Debit (-)
CB-110 66.65 66.65 0.00 0.00 0.00
CB-111 115.93 115.93 0.00 0.00 0.00
CB-112 32.87 32.87 0.00 0.00 0.00
DP-122 22.76 3.52 20.25 -19.24 1.01
DP-123 53.57 25.24 29.25 -28.33 0.92
DP-125 28.57 2.35 25.50 -26.22 -0.72
DP-126 25.61 0.95 25.60 -24.66 0.94
DP-127 11.54 1.25 12.50 -10.29 2.21
DP-128 11.55 0.56 8.25 -10.99 -2.74
DP-138 7.54 0.25 6.52 -7.29 -0.77
DP-139 1.52 0.00 0.50 -1.52 -1.02
SWMP-147 10.51 0.45 9.52 -10.06 -0.54
SWMP-148 8.71 0.35 9.53 -8.36 1.17
SWMP-158 6.17 0.22 6.25 -5.95 0.30
SWMP-159 4.45 0.25 4.52 -4.20 0.32
TOTALS 407.95 250.84 158.19 -157.10 1.09
DP: Proposed Regional Detention Pond with Outlet
CB: Proposed Regional Closed Basin with no Outlet
SWMP: Storm Water Management Ponds for Future Developments
5.3.4 Closed Basin (CB) Facilities:
The Facility Plan Update recommends acquiring drainage easement areas for a total of
nine closed basin facilities as shown in Figures 4.4.2c-1, 4-4.2d-1 and 4.4.2f-1. These
facilities lie in the West Stillwater, West Kalispell and South Kalispell study areas and
are summarized in Table 5.3-2.
Because a detention pond (DP) facility with an outlet is not feasible in these areas, a
closed basin (CB) is recommended which would require the acquisition of a drainage
easement for each pond to collect and store storm water at the 100-year level. CB’s could
serve as enhanced or future wetlands to mitigate existing wetland impacts and they could
also provide storm water treatment for future developments in the drainage basins.
The proposed CB sizes are based on the total 100-year post-development volume with a
maximum basin depth of 5-feet. It is recommended that a site-specific freeboard analysis
be used for each closed basin and that a minimum freeboard of 3-feet be maintained to
protect surrounding properties and developments. A 4 horizontal to 1 vertical inside
slope is recommended around the perimeter of the basins from the high water mark for
safety and access into and out of the basins. It is also recommended that a mimum12-foot
wide access road be provided to the basins for the maintenance and removal of sediment
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 5-5
5.0 Recommendations and Capital Improvements Plan
deposition. This sediment may need to be removed after flood events to maintain the
required capacity of the basins.
Probable cost estimates for the CB’s are included in the Appendix of Facility Plan
Update.
Table 5.3-2: Closed Basin (CB) Summary
Study Sub-Area Closed Basins Basin Volume
(acre-ft)
Basin area
(acre) Estimated Cost
CB-113A/B 28.76 5.8 $1,447,000
CB-114 31.57 6.3 $1,588,000West Stillwater River
CB-115 7.97 1.6 $401,000
CB-110 66.65 13.3 $3,354,000
CB-111 115.93 23.2 $5,835,000West Kalispell
CB-112 32.87 6.6 $1,654,000
CB-136A/B 97.05 19.4 $4,884,000
CB-137 59.1 11.8 $2,974,000South Kalispell
CB-156 38.41 7.7 $1,933,000
Total 478.31 95.7 $24,070,000
5.3.5 Conveyance Outlet Pipelines (COP) Facilities
The Facility Plan Update recommends three conveyance outlet pipelines (COP) facilities
as shown in Figures 4.4.2b-1 and 4.4.2c-1. These facilities lie in the North Kalispell and
West Stillwater study areas and are summarized in Table 5.3-3.
The existing topography from the proposed DP 118, 119, and 124 does not provide a
drainage way to convey storm water from the DP’s to the natural conveyances.
Therefore, COP would be necessary from DP’s to convey storm water to the nearest
existing drainage way so that the DP discharge would not adversely impact existing
properties and/or infrastructure.
The required pipeline length was estimated based on the topographic mapping used in the
Facility Plan Update. The pipeline size was estimated by using average flow velocity at 5
feet per second for the existing 100-year peak discharge rate. Based on the topographic
mapping, it was assumed that the pipelines would be required where open channel flow
would not be possible due to adverse grades. The distance of the adverse grades was
used to compute the pipeline length. Detailed topographic surveys and engineering
design would be required to confirm and modify these assumptions and to prepare the
construction documents prior to construction.
Probable cost estimates for the pipeline construction are included in the Appendix of
Facility Plan Update.
5-6 City of Kalispell Storm Water Facility Plan Update March 28, 2008
5.0 Recommendations and Capital Improvements Plan
Table 5.3-3: Conveyance Outlet Pipeline (COP) Summary
Study Sub-Area Conveyance Outlet
Pipeline (COP)
Pipeline
Length
(feet)
Pipeline
Diameter
(inches)
Easement
Area
(acres)
Existing
100-year
Peak
Discharge
(cfs)
Estimated
Cost
COP-118 3,500 24 2.41 9.35 $3,275,000North Kalispell COP-119 1,500 24 1.03 6.73 $1,637,000
West Stillwater COP-124 3,300 36 2.27 20.17 $4,405,000
Total 8,300 5.71 Total $9,317,000
5.3.6 Growth versus Renewal and Replacement Costs
It is important, in addition to quantifying the cost of capital improvement projects, to identify
costs associated with growth versus costs associated with renewal and replacement. Impact
fees will be used to cover the cost of growth related projects, however; these funds, by law,
cannot be used for renewal and replacement projects.
The focus of this update to the City of Kalispell Storm Water Facility Plan was specifically
on serving growth and managing growth related storm water runoff. As such the majority of
the projects and related costs outlined in this plan are 100% growth related. It will be the
responsibility of new development to pay for and implement the recommended
improvements. It may be in the best interest of the City of Kalispell to assess impact fees to,
at a minimum, acquire lands for closed basin improvements as summarized in Table 5.3-2
and construct conveyance outlet pipelines as summarized in Table 5.3-3.
COP-124 is in an area that is experiencing substantial development and impacts to storm
water runoff are already being seen along Stillwater Road. This project could be needed
within the next 3 to 5 years. It is recommended that the City proceed with design and
construction of this project as soon as practical. This project is needed partially due to
development that has already occurred in and to the north of Section 36 and partially due to
planned development in the area. Detailed analysis of the contribution of flow due to
developed acreage vs. the contribution of flow due to acreage associated with planned
development will be needed to determine the cost split between growth (impact fees) and
existing customers (rates).
COP-118 and COP-119 are in an area of extensive planned development. These projects will
most likely be needed n the 5 to 10 year horizon. It is recommended that the City begin
planning for implementing these projects. Similar to COP-124, these projects are needed
partially due to development that has already occurred and partially due to planned
development. Detailed analysis of the contribution of flow due to developed acreage vs. the
contribution of flow due to acreage associated with planned development will be needed to
determine the cost split between growth (impact fees) and existing customers (rates).
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 5-7
5.0 Recommendations and Capital Improvements Plan
5-8 City of Kalispell Storm Water Facility Plan Update March 28, 2008
Of the $24 million estimated for closed basin improvements, approximately $8.1 million is
estimated for acquisition of land. It is recommended that the City plan for acquiring these
lands over the 20-year planning horizon.
Table 5.3-4 summarizes the recommended capital improvements by year.
Table 5.3-4: Capital Improvement Summary
Estimated Cost Project
Number
Project Description
FY 08-09 FY 09-10 FY 10-11 FY 11-12 FY 12-13 Future
1 Spring Creek Drainage
Improvements $170,000 $680,000
2 Willow Glen Drainage
Improvements
$170,000 $680,000
3 COP-1241 (Stillwater Road
Drainage Improvements) $500,000 $1,952,500 $1,952,500
4 COP-1181 $500,000 $2,775,000
5 COP-1191 $400,000 $1,237,000
6 Closed Basin Land
Acquisition
$406,500 $406,500 $406,500 $406,500 $406,500 $6,067,500
Total3 $1,246,500 $4,219,000 $5,134,000 $806,500 $1,643,500 $6,067,500
1 Total project cost spread over multiple years to allow for planning, preliminary, and final design.
2 All costs are in 2007 dollars. Estimates should be escalated to the mid-point of construction for budgeting purposes.
6.0 Financial Plan
6.0 Financial Plan
6.1 Introduction
The effective implementation of a comprehensive storm water plan is dependent
upon developing a financial plan which can be supported by the utility, will meet
State and local regulatory requirements, and provides the flexibility to deal with
unforeseen changes. This section of the comprehensive plan discusses the
financial plan developed for the City’s storm water utility.
This chapter presents a financial plan which reviews the sources of funds
(revenues) and applications of funds (expenses) for the City storm water utility.
The financial plan includes projected operating and capital costs of the system for
the five-year projected period of fiscal year (FY) 2009 - 2013. The basis of the
operating costs is the fiscal year (FY) 2008 storm water system budget. The
capital improvement plan (CIP) contained within this financial plan utilizes the
capital plan developed in this comprehensive storm water plan and additional
City CIP projects from the City’s CIP and the previous Storm Water
Comprehensive Plan. The results of the financial plan will outline the annual
operating and capital needs of the storm water system and determine if the
current storm water revenues are sufficient to cover those costs.
The intent of this financial plan is to determine the relative financial and rate
impacts to the City from the proposed capital improvement projects. The
financial plan considers what level of rate adjustments may be necessary to
support the storm water operations and capital improvement plan. This analysis
should not be considered a comprehensive rate study since it did not address the
typical rate study issues of cost of service and rate design. The City plans to
conduct a comprehensive rate study in the near future, which will provide a more
detailed rate analysis to support any needed rate adjustments to implement the
comprehensive storm sewer plan.
6.2 Overview of the Financial Planning Process
In analyzing the City’s costs associated with their storm water utility, a
financial/rate setting framework was utilized. This financial rate setting
framework is referred to as the “cash basis” approach. Table 6-1 provides an
overview of the “cash basis” approach. Under this approach, there are four
financial components that should be included as a part of the City’s storm water
rates or revenue requirements. These are:
• Operation and maintenance (O&M) expenses and transfers
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 6-1
• Debt service
• Capital projects funded from rates
• Working Capital
These components, when added together, comprise the City’s storm water
revenue requirements or the total amount of expenses incurred to operate the
storm water utility as a whole. In addition to this, the method that is used to fund
and finance capital projects has a direct impact upon the City’s storm water rates.
As the bottom box of Table 6-1 details, capital projects may be funded or
financed in a number of different ways. Among these financing and funding
mechanisms are long-term debt (revenue bonds or low-interest loans), grants,
capital reserves, impact fees and rates. While this is not intended to be a
comprehensive listing of potential funding or financing sources for capital
infrastructure projects, it does provide a better understanding of the multiple
sources of financing and funding that may be available.
From a prudent financial planning perspective, the City should be funding from
rates an amount equal to or greater than the annual depreciation expense of the
storm water utility. This level of funding should, in part, enable the City to
maintain the existing infrastructure in use by the utility. Depreciation expense is
simply used as a “yardstick” of the adequate level of funding. Replacement cost
of infrastructure is typically higher than the original cost of the item.
Table 6-1. Overview of the Financial/Rate Framework
+ O&M Expenses and Transfers
+ Working Capital
+ Debt Service (P&I)
+ Capital Projects Funded from Rates
+ Total Capital Projects
– Revenue Bonds (Bond Proceeds)
– Grants
– Customer Contributions (e.g. IF’s)
= Capital Projects Funded from Rates
= Total Revenue Requirements
– Miscellaneous Revenues
= Balance Required from Rates
(i + Term)
(≥Annual
Depreciation)
+ O&M Expenses and Transfers
+ Working Capital
+ Debt Service (P&I)
+ Capital Projects Funded from Rates
+ Total Capital Projects
– Revenue Bonds (Bond Proceeds)
– Grants
– Customer Contributions (e.g. IF’s)
= Capital Projects Funded from Rates
= Total Revenue Requirements
– Miscellaneous Revenues
= Balance Required from Rates
(i + Term)
(≥Annual
Depreciation)
In the end, the financial plan should balance the funding and financing sources
for the capital projects such that it helps to minimize storm water rates to
customers over time.
6-2 City of Kalispell Storm Water Facility Plan Update March 28, 2008
6.0 Financial Plan
6.3 Past Financial History
The City completed a comprehensive water, wastewater and storm water rate
study in 2003. For the storm water utility the City approved a proposed five year
rate adjustment program for 2004 through 2008. The storm water rates were
adjusted 11.5% each year through 2008, even though the financial plan
forecasted a needed 20% increase for both 2007 and 2008. There were no
changes to the structure of the storm water rates. The storm water rate
adjustment plan was cost-based and was developed using “generally-accepted”
rate making methods and principles. In the summary of the financial projections
shown later in Table 6-4, 2007 is shown to provide historical perspective.
6.4 Development of the Financial Plan
The development of the five-year financial plan is intended to demonstrate the
City’s ability to meet its operating and capital improvement needs, while
maintaining sufficient rate levels to support those needs. As previously stated, the
financial plan was developed to review the projected revenues and expenses of
the storm water system for FY 2009-2013.
In developing the financial forecast, four cost components were reviewed:
operation and maintenance (O&M) expenses (including taxes and transfers),
capital improvements funded from rates, debt service and working capital needs.
The City does not incur state taxes for Montana. The City’s FY 2008 storm water
system budget was used as a starting point. Projections for future years were
obtained by applying annual escalation factors. The escalation factors ranged
from one percent to six percent depending on the type of cost being escalated.
Utilities (electric, natural gas) were escalated at six percent due to the sharp
increase the industry is experiencing. Impact Fee (IFs) revenues were based on
the growth projections for the test period.
The first component of the financial plan reviews the sources of funds of the
storm water system. There are two primary types of revenues received from
operations:
• Rate revenues – received from storm water service to customers, and
• Miscellaneous revenues – received from investment interest, and other
miscellaneous revenue.
The storm water rate revenue was based on budgeted information in the 2008
budget. The retail rates were adjusted 11.5% in 2008 (budget year) from the
2003 rate study. Rate revenues are projected to be $615,000 in FY 2008 and
increase to $713,000 in FY 2013. Revenue growth was estimated to be three
percent a year. Miscellaneous revenue is $72,000 in 2008 and decrease to
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 6-3
$15,000 in 2013 due to the decrease in interest income due to depletion of cash
reserves.
The total revenue, available to offset the operating and capital needs of the storm
water system, is projected to be $687,000 in FY 2008 and increase to $728,000
by FY 2013.
The second part of the financial plan is a review of the applications of funds or
expenses of the utility, or the utility expenses. Applications of funds include
operating & maintenance expenses, capital improvement projects funded from
rates, debt service, and working capital. These costs are summarized below.
Operation & Maintenance Expenses – The FY 2008 budget was used as a
starting point for the O&M expense for the storm water utility. Escalation factors
were applied to various costs (salary, benefits, supplies, other expenses) for FY
2008 to obtain projected costs. O&M expenses ranged from $589,000 in FY
2008 to $627,000 in FY 2013.
Debt Service – There are currently no outstanding bond issues for the storm
water utility. The City anticipates new bond issues and low-interest loans during
the projected period of 2008 to 2013 to assist in funding the capital projects
identified within this plan. These issues will be from State Revolving Fund
(SRF) loans estimated to be $4.4 million dollars and $4.5 million in revenue
bonds over the test period. The total debt service through 2013 will be
approximately $672,000 per year. Impact fee revenues are used to offset the
growth related bond debt service payments. The City, based on policy, does not
allow more than fifty percent of the impact revenues to be used to offset the debt
service payments. This protects the ability of the City to make debt payments in
the event of an economic down turn, with reduced growth. Net debt service
payments are $437,000 in 2013.
Capital Improvement Projects from Rates - Capital improvement projects are
related to the infrastructure to maintain and expand service. Capital
improvement projects are ongoing and can generally be divided into three types
or categories. These categories are projects related to renewal and replacements,
regulatory requirements, and growth-related facilities. Renewal and
replacements are, as the name suggests, the replacement of existing and worn out
(depreciated) facilities. Growth related facilities, on the other hand, are those
related to system expansion, system upgrades and new customers. Regulatory
requirements also drive the need for some capital improvements.
The analysis developed herein assumes the City is funding capital projects from
rates in an amount equal to or greater than the annual depreciation expense for
the storm water utility. This amount is recommended as a minimum level to fund
renewals and replacements at least at the level of annual depreciation expense.
6-4 City of Kalispell Storm Water Facility Plan Update March 28, 2008
6.0 Financial Plan
Since actual replacement costs are much higher than depreciation expense, it is
always prudent if funding for capital from rates can be higher than the level of
depreciation in any given year. The storm water utility’s total plant depreciation
was $180,000 in 2006. The projected test period shows $180,000 capital
improvements from rates in 2009 and increasing $190,000 in 2013. Over time,
the City should attempt to increase this level of funding from rates in order to
keep pace with depreciation expense as the system is expanded.
This study has incorporated the capital projects outlined in this comprehensive
plan section as part of this financial plan. Capital project costs for the five-year
plan (2009-2013) are approximately $17.5 million. The funding for these projects
is provided from $1.0 million from rates, $4.4 million from SRF loans, $4.5
million from revenue bonds, $6.0 million from developers, and $1.5 million from
capital reserves and impact fees for the five-year period. For renewal and
replacement type activities the general approach to funding them is that each year
a specific amount of funds are transferred to a reserve fund. These funds will
then be used to fund specific projects in the capital improvement plan. If these
funds are not used (during the year) the funds will remain in the capital reserve
fund and be used for future capital project funding. In this way, rates are used to
fund the capital projects in future years. All capital will be funded through a mix
of funding sources (e.g. loans, bonds, existing reserves, and impact fees, etc.). A
summary of the capital improvement projects planned and their funding sources
is presented below in Table 6-2.
Table 6-2. Summary of Storm Sewer Capital Improvement Projects ($000)
FY
08/09
FY
09/10
FY
10/11
FY
11/12
FY
12/13
Capital Outlays
Comp. Plan CIP
Northridge Heights Storm Drainage $875 $0 $0 $0 $0
Southeast Storm Drainage 0 0 1,286 0 0
Liberty Street Storm Drainage 0 142 0 0 0
2-Mile/3-Mile Dr. Spring Cr. Deten. 0 150 0 0 0
Total Comp. Plan CIP $875 $292 $1,286 $0 $0
Capital Improvement Plan
Spring Cr. Reroute/Lower Spring
Creek Overflow Constr.
$170 $750 $0 $0 $0
Stillwater Road/Willow Glen Drive 170 680 0 0 0
West Stillwater COP-124 500 1,952 1,952 0 0
North Kalispell COP-118 0 500 2,775 0 0
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 6-5
FY
08/09
FY
09/10
FY
10/11
FY
11/12
FY
12/13
North Kalispell COP-119 0 0 0 400 1,237
CB Land Acquisitions for projects 800 800 800 800 800
Total Capital Improvement Plan $1,640 $4,682 $5,527 $1,200 $2,037
Total CIP $2,515 $4,974 $6,813 $1,200 $2,037
Less: Outside Funding
From Designated Capital Reserve $21 $70 $111 $2 $0
From Operating Reserve 0 0 100 0
From Impact Fees 290 227 239 327 224
Developer Contributions 656 1,923 2,211 480 815
SRF Loans 728 1,497 1,272 101 808
Revenue Bonds 640 1,077 2,800 0 0
Total Funding $2,335 $4,794 $6,633 $1,010 $1,847
CIP From Rates $180 $180 $180 $190 $190
The capital projects listed above assume that all projects outlined in the
comprehensive plan and the City CIP for the 2009-2013 periods will be
completed. The major funding sources for the capital projects are assumed to be a
combination of existing cash reserves, impact fee revenue, SRF loans, developer
contributions and rates. There are also potentially other funding sources
available for capital improvements. These other funding sources are discussed
below.
There are several important points to mention in the capital funding assumptions.
First, this financial plan assumes, with review and direction from City
Management, that for projects identified as 80 percent or more related to growth,
40% of those project costs would come from developers as direct contributions.
The other 60% would be covered by both impact fees (increasing 100% from
current levels) and loan or bond financing. The impact fees would pay down a
portion of the growth related debt. Another alternative of assuming 80%
developer contributions was analyzed. In that scenario the impact fees would
increase 50% above current levels and the annual service charges were also cut in
half.
It appears, from the results of this alternative scenario, that a more equitable and
balanced approach would include two elements: 1) an increase in impact fees
between 50 and 100 percent of current fees, which should occur as soon as
6-6 City of Kalispell Storm Water Facility Plan Update March 28, 2008
6.0 Financial Plan
possible, and 2) an assumption of greater than 40% of the growth related facility
costs be borne directly by developers. In this way, existing customers are
shielded from the impacts of growth related project costs.
The City is planning to take a more in-depth look at the level of direct
contributions and impact fees over the next several months, and during the rate
study. It will be important to ensure that growth is paying its share of the growth
related facilities, through both these direct developer contributions and increases
in impact fees to cover the balance of costs both directly, and through reduction
of growth related debt payments.
It should also be noted that for budget FY 07/08 there are $616,000 in capital
improvements. The two largest projects are the Lift Station #1 design and
replacement for $185,000 and storm drain corrections for $145,000. The funding
sources for the 07/08 projects are from cash reserves, $65,000 developer
contributions, and $95,000 from impact fees.
6.5 Potential Funding/Financing Sources
The discussion above has used the terms funding and financing. For purposes of
this report, funding and financing are two different terms. Financing is a method
of paying for infrastructure, such as long-term borrowing. Debt service
payments on a revenue bond (i.e. the financing method) must be paid from a
funding source (e.g. rates, impact fees, etc.). This subsection will discuss the
various funding sources and financing methods available to the City.
There are a number of different funding sources for the storm water utility that
may be available to the City.
User Fees/Rates - The most basic funding source available to the City is user
charges or rates. For a storm water utility, the rates are typically based upon an
equivalent residential unit (ERU) or an impervious surface unit (ISU). An ISU
relates to the lot size of the property or the impervious surface area that
contributes to storm water runoff. For storm water utilities, the vast majority of
funding comes from rates.
Impact Fees – Impact fees (IFs), also referred to as system development charges
(SDCs), are imposed upon new development as a condition of development. The
purpose of IFs is to either reimburse existing customers for the investment made
in capacity to support development, or to finance future capital infrastructure
projects that create expanded capacity. The City updated these fees in 2007 and
is required by Montana state law to review them every two years. With the
growth related capital identified both in the City CIP and in this Comprehensive
Plan, the fees should be updated as soon as possible to capture the portion new
growth owes for the new facilities required to meet their needs.
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 6-7
Other Miscellaneous Funding - In addition to the above funding sources, there
are also a variety of other funding sources, but typically of a much lesser extent.
These other funding sources may take the form of property taxes, voter approved
sales taxes, special fees and charges, and interest earnings on reserves.
The storm water utility projects identified as part of the Kalispell Capital
Improvement Planning process are generally eligible for financial assistance
from the numerous state or federal grant or low interest loan programs. Most
grant and loan programs require preparation of a Preliminary Engineering Report
to support the proposed project. The City of Kalispell has been successful in the
past in obtaining grant and loan assistance for improvements to the wastewater
and water systems. A more detailed description of appropriate potential funding
programs for storm water follows.
Grants - A very limited funding source that may be available is grants. The
advantage of grants is that they do not need to be re-paid. Unfortunately, grants
have become increasingly rare and for financial planning purposes should not be
relied upon as a funding source unless they are already secured. Grant programs
usually entail a competitive process of project evaluation which prioritizes public
health need, public safety, environmental degradation and financial need.
Projects primarily to support new growth do not complete well for grant funding.
Among the grant programs are the following:
Community Development Block Grant Program (CDBG) - This grant
program is administered by the Montana Department of Commerce. All CDBG
applications must document that at least 51 percent of the non-administrative
funds requested for a CDBG project are clearly designed to meet the needs for
low and moderate-income families. The CDBG program has a maximum limit of
$500,000 per project. Having a high percentage of low and moderate-income
people in the community and the presence of a high potential health threat helps a
community compete for a CDBG grant. Good local involvement in the planning
process also helps grant competitiveness. Applications are made to this program
on an annual basis. Planning grants for engineering and grant preparation
expenses are also available from the CDBG Program.
Federal State and Tribal Assistance Grant (STAG) - This source of funding is
derived from a special line item appropriation from Congress and is typically
earmarked for water pollution control projects, although other types of projects
have been funded. Application can be submitted annually and generally consist
of a simple request to the congressional delegation including a fact sheet
regarding project need, costs, readiness to proceed, etc. These grants typically go
toward wastewater projects, but if there were a great enough need due to water
quality problems, a storm sewer project may qualify. The program is
6-8 City of Kalispell Storm Water Facility Plan Update March 28, 2008
6.0 Financial Plan
administered by the MDEQ, similar to the old EPA Construction Grants
program. STAG grants will typically require a non-federal match.
One of the challenges of a storm water utility is the limited funding sources that
are available, and the ability of the utility to support the use of long-term debt as
a means of financing. The relatively small size of the capital projects; along with
very low rates, often require a City to finance storm water projects as a combined
debt issue (i.e. water/sewer/storm water). While in theory there are a variety of
financing sources available, in reality, most are not considered or available.
Provided below is a detail of some potential financing sources for the storm
water utility.
Revenue Bonds – Revenue bonds pledge the revenues of the utility to repay the
debt. Revenue bonds are a very viable source of financing for a storm water
utility, but are often financed in combination with another utility’s issuance. This
is done for two reasons. First, the size of the required capital financing may not
make it economically viable to issue debt on a “stand-alone” basis. More
importantly, the second reason is the legal and rate covenants associated with a
revenue bond. The utility is required to maintain their rates at a sufficient level
to assure repayment of the debt service. This is monitored via a debt service
coverage ratio (DSC). DSC ratios typically fall in the range of 1.25 to 1.50. That
means, a utility or City must be able to pay the principal, interest, and another 25
to 50 percent of that total payment. This is a financial measure of the health of
the utility(ies). This buffer ensures bond holders that the principal and interest
payments will in fact be made. By issuing a combined utility bond, the coverage
can be provided (met) by the other utility and it does not place as much financial
and rate pressure on the storm water utility. Prior to any rate adjustments, the
storm water utility is pressed to meet the principal and interest payments solely
from current rate revenue in the last three years of the review period. The City
will need to monitor this financial parameter carefully over the next five years.
Legislation allows revenue bonds to be supported by an assessment placed upon
measurable property values such as square footage. These bonds, in some cases,
can be backed by the general obligation of the taxpayers (i.e. “double barreled
bonds”).
General Obligation (G.O.) Bonds – G.O. bonds are similar to revenue bonds,
but have some distinct differences. First, G.O. bonds are typically backed by
property taxes. The bonds are typically authorized by a vote of the people.
Utilities typically do not use G.O. bonds due to the voting requirement, but in
addition, most cities prefer to reserve their G.O. bonding capacity for other
municipal projects that are not enterprise fund related.
Utility Special Improvement Districts – A utility special improvement district
(SID) is a group of property owners that agree to pay for specific improvements
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 6-9
that benefit them directly. The utility typically issues a form of long-term debt
and the property owners are assessed a property tax to repay the loan. This
financing option is used most often when an improvement will clearly benefit
only select properties, and not provide overall benefits to the entire system.
Montana Treasure State Endowment Program - The Treasure State
Endowment Program (TSEP) is a state-funded grant and loan program designed
to assist cities, districts, and counties in financing wastewater systems, drinking
water systems, sanitary or storm water systems, solid waste disposal and
separation systems, and bridges. Grant amounts from this program are capped at
$750,000 and generally require a 50% match. Projects submitted for assistance
by this program would be due in May of each year and require legislative
approval, the earliest coming in spring of the following year. Grant funds are not
available until July of that following year, at the earliest. The TSEP program
also has grant funds available for preparation of Preliminary Engineering
Reports. Projects showing significant public health or safety needs fare well in
the TSEP program. Financial need and local planning is also a consideration.
DNRC Water Development Grant and Loan Program - This grant and loan
program is administered by the Montana Department of Natural Resources and
Conservation. The DNRC grants are limited to $100,000. Projects that conserve,
manage, develop or protect Montana's renewable resources are eligible for
funding. Projects that conserve or reuse natural resources or promote the sound
use of water tend to do well in competing for these grant funds. Applications to
this program are received in May, on the same schedule as TSEP grants. The
Renewable Resource Loan Program makes loans to communities for renewable
resource projects which could include water, wastewater or storm drain projects
similar the Montana State Revolving Loan Program. The program was started in
1981 by the Montana Legislature, which granted a total of $250 million in coal
tax bonding authority. The DNRC encourages communities to apply to the SRF
program first before considering the Renewable Resource Loan program.
USDA Rural Utility Services (RUS) -The RUS loan and grant program is
administered by the Rural Utilities Services of the U.S. Department of
Agriculture, formerly known as the Farmers Home Administration (FmHA).
RUS has grants and loans available with the mixture of the two dependent on the
community’s residential income and target user rates. Loan terms for as much as
40 years are possible. Water and sewer systems are typically funded with
financial assistance from this program.
Montana Wastewater and Drinking Water State Revolving Fund Loan
Programs -While primarily a water and wastewater loan program, storm water
projects showing water pollution control benefits can also be funded with SRF
loan assistance.
6-10 City of Kalispell Storm Water Facility Plan Update March 28, 2008
6.0 Financial Plan
Intercap Loan Program - The Montana Board of Investments of the Montana
Department of Commerce (DOC) administers this loan program which is
available to communities for paying for capital improvements. The INTERCAP
Program is a low cost, variable-rate program that lends money to Montana local
governments, state agencies and the university system for the purpose of
financing or refinancing the acquisition and installation of equipment or personal
and real property and infrastructure improvements. The Board of Investments
issues tax-exempt bonds and loans the proceeds to eligible borrowers. In
addition to long-term financing, INTERCAP is an excellent source for interim
financing. The loan term is up to 10 years or the useful life of the project. The
funding is always available and is not subject to a funding cycle. Maximum loan
amount per project depends on borrower’s legal debt authority.
While the above list of possible grant and loan opportunities for the City is not
exhaustive, it does however, highlight the most probable outside funding sources
available to the City for its storm sewer capital improvements.
6.6 Summary of the Financial Projections
A summary of the financial plan and resulting financial status of the storm water
system is provided below in Table 6-3. This is an abbreviated summary of the
actual detailed analysis that was developed for the City, but it does summarize
the major elements of the City’s analysis, along with the findings and
conclusions.
Another indicator of financial viability is the debt service coverage ratio. As can
be seen in Table 6-4, the target value of 1.25 debt service coverage, with impact
fee revenue not included, is not met in most of the years. The debt service
coverage ratio, after rate increases and impact fee revenue are included in the
calculation, meets the requirements.
Table 6-3. Summary of the City's Five-Year Financial Plan ($000)
Actual
FY
06/07
Budget
FY
07/08
FY
08/09
FY
09/10
FY
10/11
FY
11/12
FY
12/13
Sources of Funds
Rate Revenues $538 $615 $633 $652 $672 $692 $713
Misc. Revenues 80 72 23 23 24 20 19
Total Sources of Funds $618 $687 $656 $675 $696 $712 $732
Applications of Funds
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 6-11
Actual
FY
06/07
Budget
FY
07/08
FY
08/09
FY
09/10
FY
10/11
FY
11/12
FY
12/13
Operating Costs $412 $588 $559 $575 $592 $610 $627
CIP from Rates 0 131 180 180 180 190 190
Debt Service (Net) 0 0 0 45 351 350 438
Change in Working Capital 186 0 4 4 4 7 9
Total Revenue
Requirement
$598 $719 $743 $804 $1,127 $1,157 $1,264
Balance/(Defic.) of
Revenue
$20 ($32)($87)($129)($431) ($445) ($532)
Cumulative Deficit as a
% of Rates
-3.7% 5.3%13.8%19.8%64.2% 64.4% 74.7%
Other Financial Measures -
Debt Service Coverage:
Without Impact Fees
Before Rate Adjustments 0.00 0.00 0.72 0.26 0.13 0.13 0.13
After Rate Adjustments 0.00 0.00 1.45 0.81 0.57 0.77 0.92
With Impact Fees
Before Rate Adjustments 0.00 0.00 3.16 1.96 0.98 1.00 0.94
After Rate Adjustments 0.00 0.00 3.89 2.51 1.42 1.63 1.73
Change in Working Capital:
The term “Change in Working Capital” indicates the use of or restoration of
reserves for various cost purposes. In the case of the storm water utility, it can be
seen in Table 6-4 that over the projected time period, each year an amount less
than $10,000 is added to the operating reserve (working capital) in order to
maintain or meet the recommended minimum balance for that reserve of 90 days
of O&M expenses. The balance is above this target for the entire review period,
until 2013, when it just meets the minimum target. It will be important for the
City to monitor this fund balance in future years and maintain the 90 day
minimum balance in order to ensure adequate cash flow for expenses.
6-12 City of Kalispell Storm Water Facility Plan Update March 28, 2008
6.0 Financial Plan
Table 6-4 also indicates the City should also monitor the debt service coverage
requirement and try to move to a financial position where the utility can meet the
1.0, and preferably a 1.25 on a stand alone basis with impact fees included in the
calculation.
As can be seen from the table above, rate adjustments will be required in FY
2009 through 2013. These adjustments will need to be made to meet the on-
going needs of the storm water utility system, as identified within this document.
It should be noted that the balance or deficiencies in any single year are
cumulative; any adjustments in the initial years will reduce the deficiency in the
following years. The total level of deficiency is projected to be approximately
$532,000 or 74.7% by 2013. It was determined that a series of rate adjustments
beginning in 08/09 are necessary. Over the five-year period, rates need to be
adjusted upwards each year in order to adequately and properly fund the City’s
storm water utility O&M and capital infrastructure needs.
It is important to note that this level of adjustment is predicated upon an assumed
three percent per year level of growth of the system. Should this growth slow
down, or not occur, the level of required rate adjustment should be reviewed.
Details of the financial plan can be found in Appendix E.
6.7 Rate Impacts
While this plan is not a comprehensive rate study, it can provide relative
guidance to the City of the potential rates over time and the needed adjustments
over the projected five-year period. Based upon the financial plan developed
herein, the storm water utility will operate at a deficit during the five-year period
of 2009 – 2013. It was determined that a series of rate adjustments beginning in
08/09 are necessary. The proposed adjustments in Table 6-4 show an 11.8
percent rate adjustment for each year of the five year period. The rates should be
reviewed at the end of the five-year period to make sure financial changes have
not occurred. Table 6-4 provides a summary of the rate transition plan for the
storm sewer utility.
Table 6-4. Overview of the Rate Transition Plan
FY
07/08
FY
08/09
FY
09/10
FY
10/11
FY
11/12
FY
12/13
Present
Average
Annual
Residential
Rate
$3.48
Proposed Rate Adjustments 0.0% 11.8% 11.8% 11.8% 11.8% 11.8%
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 6-13
FY
07/08
FY
08/09
FY
09/10
FY
10/11
FY
11/12
FY
12/13
Projected Avg. Annual Residential Rate $3.48 $3.90 $4.35 $4.85 $5.45 $6.10
$ Change Per Assessment $0.00 $0.42 $0.45 $0.50 $0.60 $0.65
Cumulative $ Change Per Assessment $0.00 $0.42 $0.87 $1.37 $1.97 $2.62
[1] – Assessed annually on the customers property tax bill.
With the above rate increases, in FY 11 and FY 12 reserves will be needed to
meet total operating and capital needs. While this is not a good practice on an
on-going basis, it is appropriate on a temporary basis if the long-term picture
shows improvements, which is the case. By FY 13 the utility is fully covering
total costs with that year’s revenue. Reserve funding appears adequate to
accommodate this temporary need.
6.8 Review of the City’s Storm Water Rates
The City has adopted storm water rates to meet their financial requirements.
Provided in Table 6-5 are the current (2007/2008) adopted storm water rates of
the City.
Table 6-5. Overview of the City's Current Storm Water Rates
Category/Description $/square foot
(1) Vacant Land up to 2 Acres $0.0030
Maximum Annual Charge $260.85
(2) Residential up to ½ Acre $0.0058
Maximum Annual Charge $126.08
(3) Commercial 90% Covered $0.0104
(4) Commercial 100% Covered $0.0130
The City’s has four categories for storm water rates. The first is for vacant land
up to 2 acres, the second is for residential property up to one-half acre in size, the
third is for commercial land up to 90% covered with impervious area, and the
final is for all commercial with greater than 90% covered. Each of these
categories has a charge per square foot. The charge is collected on the property
tax bill sent to the City’s customers.
These rates should uniformly be increased by 11.8% per year over the next five
year period to meet the financial needs of the utility. The City may wish to
develop a cost of service analysis as part of the rate study to determine if any rate
design adjustments should be considered.
6-14 City of Kalispell Storm Water Facility Plan Update March 28, 2008
6.0 Financial Plan
March 28, 2008 City of Kalispell Storm Water Facility Plan Update 6-15
6.9 Summary of Storm Water Financial Plan
The results provided within this section were developed using the City’s financial
records, are cost-based and utilize sound financial practices and guidelines. The
financial plan results indicate that storm water rates for the five-year projected
time horizon of FY 2009 to FY 2013 will be deficient in meeting the projected
O&M, capital, and debt service requirements. The levels of rate adjustments
needed presented within this section document the needs for future rate
adjustments. Continued analysis and monitoring of capital funding and financing
and other major changes in costs will provide the City with the information
necessary to determine future rate adjustments. The projections and findings of
this financial plan will enable the City’s storm water utility to operate on a
financially sound basis.
APPENDIX
APPENDIX A: Regulatory Storm Water Permits:
City of Kalispell Ordinance No. 1600
MS4 General Permit Co-Application
MS4 Authorization MTR040005
City of Kalispell Ordinance No. 1600
STORM SEWER EXHIBIT 1
Budget
FY 2007/08 FY 2008/09 FY 2009/10 FY 2010/11 FY 2011/12 FY 2012/13
SOURCES OF FUNDS
Present Rate Revenues $615,000 $633,450 $652,454 $672,027 $692,188 $712,954
Miscellaneous Revenues 72,500 22,634 22,685 24,152 19,679 18,556
---------------- ---------------- ---------------- ---------------- ---------------- ----------------
TOTAL SOURCES OF FUNDS $687,500 $656,084 $675,138 $696,179 $711,867 $731,510
APPLICATIONS OF FUNDS
Operating Costs $588,885 $559,586 $575,754 $592,404 $609,551 $627,209
---------------- ---------------- ---------------- ---------------- ---------------- ----------------
TOTAL O&M EXPENSE $588,885 $559,586 $575,754 $592,404 $609,551 $627,209
CAPITAL PROJECT BUDGET
Capital Improvements $616,248 $2,515,000 $4,974,960 $6,813,350 $1,200,000 $2,037,000
Less: Outside Funding 485,000 2,335,000 4,794,960 6,633,350 1,010,000 1,847,000
---------------- ---------------- ---------------- ---------------- ---------------- ----------------
TOTAL CIP FROM RATES $131,248 $180,000 $180,000 $180,000 $190,000 $190,000
Debt Service (Net) [1]$0 $0 $44,330 $351,027 $350,409 $437,549
Change in Working Capital $0 $4,180 $4,242 $4,306 $7,870 $9,436
---------------- ---------------- ---------------- ---------------- ---------------- ----------------
TOTAL REVENUE REQUIREMENTS $720,133 $743,766 $804,326 $1,127,738 $1,157,830 $1,264,195
BALANCE/(DEFICIENCY) IN RATES ($32,633) ($87,682) ($129,188) ($431,559) ($445,963) ($532,685)
RATE ADJUSTMENT AS A % OF RATE REV 5.3% 13.8% 19.8% 64.2% 64.4% 74.7%
PROPOSED RATE ADJUSTMENT 0.0% 11.8% 11.8% 11.8% 11.8% 11.8%
AVERAGE MONTHLY RESIDENTIAL RATE $3.48 $3.90 $4.35 $4.85 $5.45 $6.10
Debt Service Coverage Ratio Before Impact Fees
Before Rate Adjustment 0.00 0.72 0.26 0.13 0.13 0.13
After Rate Adjustment 0.00 1.45 0.81 0.57 0.77 0.92
Debt Service Coverage Ratio with Impact Fees
Before Rate Adjustment 0.00 3.16 1.96 0.98 1.00 0.94
After Rate Adjustment 0.00 3.89 2.51 1.42 1.63 1.73
Target for Reserve (Emergency, Capital and Operating) $313,317 $306,092 $310,079 $314,184 $318,412 $322,766
Balance/(Deficiency) from Target $853,963 $697,301 $687,910 $436,277 $225,335 $321,534
[1] No current debt service in 07/08. The 08/09 debt service is net of impact fees.
Projected
CITY OF KALISPELL - STORM SEWER
SUMMARY OF SOURCES AND APPLICATIONS OF FUNDS
HDR Inc 3/19/2008
SS - 1
CITY OF KALISPELL
STORM SEWER EXHIBIT 2
ESCALATION FACTORS
Budget
Escalation Factors FY 2007/08 FY 2008/09 FY 2009/10 FY 2010/11 FY 2011/12 FY 2012/13
Revenues:
Assessments Calculated 3.0%3.0%3.0%3.0%3.0%
Other Income Budget 1.0%1.0%1.0%1.0%1.0%
Interest Earnings Budget 3.0%3.0%3.0%3.0%3.0%
Expenses:
Labor Budget 2.5%2.5%2.5%2.5%2.5%
Benefits Budget 4.0%4.0%4.0%4.0%4.0%
Materials & Supplies Budget 3.0%3.0%3.0%3.0%3.0%
Miscellaneous Operating Expenses Budget 1.5%1.5%1.5%1.5%1.5%
Growth Rate Calculated 3.0%3.0%3.0%3.0%3.0%
Debt Issues
Low Interest Loans
Term (Max 10 Year)10 10 10 10 10 10
Rate 3.50% 3.50% 3.50% 3.50% 3.50% 3.50%
Revenue Bonds
Term 20 20 20 20 20 20
Rate 5.00% 5.00% 5.00% 5.00% 5.00% 5.00%
Projected
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CITY OF KALISPELL Page 1 of 4
STORM SEWER EXHIBIT 3
SOURCES AND APPLICATIONS OF FUNDS
Budget
FY 2007/08 FY 2008/09 FY 2009/10 FY 2010/11 FY 2011/12 FY 2012/13 Notes:
SOURCES OF FUNDS
Charges for Services
343370 Storm Assessments-Billed $615,000 $633,450 $652,454 $672,027 $692,188 $712,954 Esc. as Assessments
Other 000000Esc. as Assessments
------------ ------------ ------------ ------------ ------------ ------------
Total Charges for Services $615,000 $633,450 $652,454 $672,027 $692,188 $712,954
Other/Miscellaneous Revenue
343034 Permit Fees $500 $505 $510 $515 $520 $526 Esc. As Other Income
334040 Petro Tank/Monitoring Reimb State 10,000 10,300 10,609 10,927 11,255 11,593 Esc. As Other Income
363040 Penalty & Interest 2,000 2,000 2,000 2,000 2,000 2,000 Esc. As Other Income
371010 Interest 60,000 9,829 9,566 10,709 5,904 4,438 Calculated on Oper. Reserves
------------ ------------ ------------ ------------ ------------ ------------
Total Other Revenue $72,500 $22,634 $22,685 $24,152 $19,679 $18,556
Total Sources of Funds $687,500 $656,084 $675,138 $696,179 $711,867 $731,510
APPLICATIONS OF FUNDS
Personnel Services:
110 Salaries & Wages (includes taxes)$274,135 $280,988 $288,013 $295,213 $302,594 $310,159 Esc. as Labor
121 Overtime 4,500 4,613 4,728 4,846 4,967 5,091 Esc. as Labor
153 Health Insurance 61,912 64,388 66,964 69,643 72,428 75,325 Esc. as Benefits
155 Retirement 15,849 16,483 17,142 17,828 18,541 19,283 Esc. as Benefits
------------ ------------ ------------ ------------ ------------ ------------
Total Personnel Services $356,396 $366,472 $376,847 $387,530 $398,530 $409,858
Materials and Services:
210 Office Supplies & Small Office Equipment $3,850 $3,966 $4,084 $4,207 $4,333 $4,463 Esc. as Mat & Suppl
214 GIS Supplies 3,000 3,090 3,183 3,278 3,377 3,478 Esc. as Mat & Suppl
215 Computer Supplies 10,000 10,300 10,609 10,927 11,255 11,593 Esc. as Mat & Suppl
216 Computer Equipment 5,000 5,150 5,305 5,464 5,628 5,796 Esc. as Mat & Suppl
218 Equipment (non capital)4,000 4,120 4,244 4,371 4,502 4,637 Esc. as Mat & Suppl
221 Safety Equip. & Supplies 5,500 5,665 5,835 6,010 6,190 6,376 Esc. as Mat & Suppl
229 Other Supplies 2,500 2,575 2,652 2,732 2,814 2,898 Esc. as Mat & Suppl
231 Gas & Oil 8,500 8,755 9,018 9,288 9,567 9,854 Esc. as Mat & Suppl
241 Consumable Tools 500 515 530 546 563 580 Esc. as Mat & Suppl
320 Printing-blue prints, etc.200 206 212 219 225 232 Esc. as Mat & Suppl
345 Telephone & Communications 600 618 637 656 675 696 Esc. as Mat & Suppl
353 Auditing 600 618 637 656 675 696 Esc. as Mat & Suppl
354 Contract Services 9,000 9,270 9,548 9,835 10,130 10,433 Esc. as Mat & Suppl
356 Storm Water Reg Compliance Program 10,000 10,300 10,609 10,927 11,255 11,593 Esc. as Mat & Suppl
357 Facility Plan Phase II 45,000 00000One-time cost
359 TMDL/Permit 50,000 51,500 53,045 54,636 56,275 57,964 Esc. as Mat & Suppl
360 Repair & Maint. Services 1,000 1,030 1,061 1,093 1,126 1,159 Esc. as Mat & Suppl
362 Groundwater Monitoring 20,000 20,600 21,218 21,855 22,510 23,185 Esc. as Mat & Suppl
Projected
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CITY OF KALISPELL Page 2 of 4
STORM SEWER EXHIBIT 3
SOURCES AND APPLICATIONS OF FUNDS
Budget
FY 2007/08 FY 2008/09 FY 2009/10 FY 2010/11 FY 2011/12 FY 2012/13 Notes:
Projected
371 Curb & Gutter 5,000 5,150 5,305 5,464 5,628 5,796 Esc. as Mat & Suppl
373 School & Travel 3,500 3,605 3,713 3,825 3,939 4,057 Esc. as Mat & Suppl
388 Medical Services 250 258 265 273 281 290 Esc. as Mat & Suppl
410 Construction Materials 10,000 10,300 10,609 10,927 11,255 11,593 Esc. as Mat & Suppl
510 Property & Liability Ins.7,500 7,725 7,957 8,195 8,441 8,695 Esc. as Mat & Suppl
521 Central Garage Transfer 2,000 2,060 2,122 2,185 2,251 2,319 Esc. as Mat & Suppl
522 Administrative Transfer 16,480 16,974 17,484 18,008 18,548 19,105 Esc. as Mat & Suppl
528 Data Processing Transfer 3,859 3,975 4,094 4,217 4,343 4,474 Esc. as Mat & Suppl
532 Lease Payments 4,650 4,790 4,933 5,081 5,234 5,391 Esc. as Mat & Suppl
------------ ------------ ------------ ------------ ------------ ------------
Total Materials and Services $232,489 $193,114 $198,907 $204,874 $211,021 $217,351
Total Operations & Maintenance Expense $588,885 $559,586 $575,754 $592,404 $609,551 $627,209
Capital Improvement Projects
$1,447,000 W Stillwater River CB-113A/B $0 $0 $0 $0 $0 $0 City CIP Plan
1,588,000 W Stillwater River CB-114 000000City CIP Plan
401,000 W Stillwater River CB-115 000000City CIP Plan
3,354,000 W Kalispell CB-110 000000City CIP Plan
5,835,000 W Kalispell CB-111 000000City CIP Plan
1,654,000 W Kalispell CB-112 000000City CIP Plan
4,884,000 S Kalispell CB-136A/B 000000City CIP Plan
2,974,000 S Kalispell CB-137 000000City CIP Plan
1,933,000 S Kalispell CB-156 000000City CIP Plan
1 Spring Creek Reroute/Lower Spring Creek Overflow 0 170,000 750,000 0 0 0 Comp Plan
2 Stillwater Road/Willow Glen Drive 75,000 170,000 680,000 0 0 0 Comp Plan
3 West Stillwater COP-124 [1]0 500,000 1,952,500 1,952,500 0 0 3-5 Years; Comp Plan
4 North Kalispell COP-118 [1]0 0 500,000 2,775,000 0 0 5-10 Years: Comp Plan
5 North Kalispell COP-119 [1]0000400,000 1,237,000 5-10 Years: Comp Plan
6 CB Land Acquisitions for projects 0 800,000 800,000 800,000 800,000 800,000 CIP $24 mill CB projects/30 yrs.
Northridge Heights Storm Drainage 0 875,000 0000City CIP Plan
Southeast Storm Drainage 0 0 0 1,285,850 0 0 City CIP Plan
Liberty Street Storm Drainage 0 0 142,460 0 0 0 City CIP Plan
2-Mile/3-Mile Drive Spring Creek Detention Analysis 0 0 150,000 0 0 0 City CIP Plan
Lift Station #1 Design & Replace 184,998 00000City CIP Plan
Facility Plan Phase 1 & 2 81,000 00000City CIP Plan
Storm Drain Corrections 145,000 00000City CIP Plan
Glenwood Dr Storm Drainage Construction 90,000 00000City CIP Plan
Machinery & Equipment 40,250 00000City CIP Plan
------------ ------------ ------------ ------------ ------------ ------------
Total Capital Improvements $616,248 $2,515,000 $4,974,960 $6,813,350 $1,200,000 $2,037,000
Less: Outside Funding Sources
From Designated Captial Reserve $0 $21,500 $70,000 $110,580 $101,520 $655 Input
From Operating Reserve 325,000 00000Input
From Impact Fees 95,000 289,500 227,960 239,500 327,480 223,545 50% of Impact Fees
Developer Contributions 65,000 656,000 1,923,000 2,211,000 480,000 814,800 40% developer contributions
HDR Inc 3/19/2008
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CITY OF KALISPELL Page 3 of 4
STORM SEWER EXHIBIT 3
SOURCES AND APPLICATIONS OF FUNDS
Budget
FY 2007/08 FY 2008/09 FY 2009/10 FY 2010/11 FY 2011/12 FY 2012/13 Notes:
Projected
Low Interest 000000
SRF Loans 0 728,000 1,497,000 1,272,270 101,000 808,000
Revenue Bonds 0 640,000 1,077,000 2,800,000 0 0
------------ ------------ ------------ ------------ ------------ ------------
Total Outside Funding Sources $485,000 $2,335,000 $4,794,960 $6,633,350 $1,010,000 $1,847,000
Total Capital Projects Funded from Rates $131,248 $180,000 $180,000 $180,000 $190,000 $190,000 Deprec. Exp. $180,000 in 2006
Debt Service
Low Interest $0 $0 $0 $0 $0 $0 10 Years @ 3.5%
SRF Loans 0 51,223 156,553 246,072 253,178 310,030 20 Years @ 3.5%
Revenue Bonds 0 51,355 137,777 362,456 362,456 362,456 20 Years @ 5.0%
------------ ------------ ------------ ------------ ------------ ------------
Total Debt Service $0 $102,578 $294,330 $608,527 $615,634 $672,486
Less: Impact Fees $0 $102,578 $250,000 $257,500 $265,225 $234,936 <=50% of Impact Fees
--------------- --------------- --------------- --------------- --------------- ---------------
Net Debt Service Payment $0 $0 $44,330 $351,027 $350,409 $437,549
Change in Working Capital
Operating Fund $0 $0 $0 $0 $3,500 $5,000
Designated Capital/Equipment Replacement Fund 000000
Miscellaneous Operating Expenses 0 4,180 4,242 4,306 4,370 4,436 As Misc Operating Expenses
----------- ----------- ----------- ----------- ----------- -----------
Total Change in Working Capital $0 $4,180 $4,242 $4,306 $7,870 $9,436
TOTAL REVENUE REQUIREMENTS $720,133 $743,766 $804,326 $1,127,738 $1,157,830 $1,264,195
Balance/(Deficiency) of Funds ($32,633) ($87,682) ($129,188) ($431,559) ($445,963) ($532,685)
RATE ADJUSTMENT AS % OF RATES 5.3% 13.8% 19.8% 64.2% 64.4% 74.7%
Proposed Rate Adjustment 0.0% 11.8% 11.8% 11.8% 11.8% 11.8%
Addt'l Rev from Proposed Adjustments $0 $74,747 $163,064 $267,074 $389,224 $532,336
Net Bal/(Def) of Funds After Rate Adj.($32,633) ($12,935) $33,876 ($164,485) ($56,739) ($349)
Additional Rate Increase Needed 5.3%2.0%-5.2% 24.5%8.2%0.0%
AVERAGE MONTHLY RESIDENTIAL RATE $3.48 $3.90 $4.35 $4.85 $5.45 $6.10
Debt Service Coverage Ratio Before Impact Fees
Before Rate Adjustment 0.00 0.72 0.26 0.13 0.13 0.13 Minimum = 1.25
After Rate Adjustment 0.00 1.45 0.81 0.57 0.77 0.92
Debt Service Coverage Ratio with Impact Fees
Before Rate Adjustment 0.00 3.16 1.96 0.98 1.00 0.94 Minimum = 1.25
After Rate Adjustment 0.00 3.89 2.51 1.42 1.63 1.73
[1] These are primarily growth related projects which will be funded from impact fee and developer funds.
HDR Inc 3/19/2008
SS - 5
CITY OF KALISPELL Page 4 of 4
STORM SEWER EXHIBIT 3
SOURCES AND APPLICATIONS OF FUNDS
Budget
FY 2007/08 FY 2008/09 FY 2009/10 FY 2010/11 FY 2011/12 FY 2012/13 Notes:
Projected
FUND BALANCES
10100 Operating Cash
Beginning Balance $685,250 $327,617 $318,862 $356,980 $196,800 $147,932
Plus: Additions of Funds 00003,500 5,000
Miscellaneous Operating Expenses 0 4,180 4,242 4,306 4,370 4,436
Net Bal/(Def) of Funds After Rate Adj.(32,633) (12,935) 33,876 (164,485) (56,739)(349)
Less: Uses of Funds 325,000 00000
Ending Balance $327,617 $318,862 $356,980 $196,800 $147,932 $157,019
Minimum Target Balance: 90 Days O&M + Taxes $145,205 $137,980 $141,967 $146,072 $150,300 $154,654
10120 Impact Fee Reserves (Plant Investment Fees/Capital Capacity Related)
Beginning Balance $186,551 $281,551 $147,919 $174,397 $197,629 $141,303
343033 Plus: Impact Fees 190,000 250,000 500,000 515,000 530,450 546,364 Esc. as Assmts; Incr. 100% '09/10
Interest Earnings 0 8,447 4,438 5,232 5,929 4,239 As Interest
Less: Uses of Funds - CIP 95,000 289,500 227,960 239,500 327,480 223,545
Use of Funds - Debt Service 0 102,578 250,000 257,500 265,225 234,936
Ending Balance $281,551 $147,919 $174,397 $197,629 $141,303 $233,424
10122 Capital Reserve
Beginning Balance $143,112 $143,112 $143,112 $143,112 $143,112 $143,112
Plus: Additions of Funds 000000
Less: Uses of Funds 000000
Ending Balance $143,112 $143,112 $143,112 $143,112 $143,112 $143,112
10127 Emergency Reserve
Beginning Balance $25,000 $25,000 $25,000 $25,000 $25,000 $25,000
Plus: Additions of Funds 000000
Less: Uses of Funds 000000
Ending Balance $25,000 $25,000 $25,000 $25,000 $25,000 $25,000
10190 Designated for Equipment Replacement
Beginning Balance $40,000 $40,000 $40,000 $40,000 $40,000 $40,000
Plus: Additions of Funds 000000
Less: Uses of Funds 000000
Ending Balance $40,000 $40,000 $40,000 $40,000 $40,000 $40,000
10193 Designated for Capital Projects
Beginning Balance $350,000 $350,000 $328,500 $258,500 $147,920 $46,400
Plus: R&R from Rates 000000
Less: Uses of Funds 0 21,500 70,000 110,580 101,520 655
Ending Balance $350,000 $328,500 $258,500 $147,920 $46,400 $45,745
Total All Cash $1,167,280 $1,003,393 $997,989 $750,461 $543,747 $644,300
Target for Reserve (Emergency, Capital and Operating)$313,317 $306,092 $310,079 $314,184 $318,412 $322,766
Balance/(Deficiency) from Target $853,963 $697,301 $687,910 $436,277 $225,335 $321,534
HDR Inc 3/19/2008
SS - 6
CITY OF KALISPELL
STORMWATER EXHIBIT 4
HISTORICAL REVENUE REQUIRMENTS
2001-2002 2002-2003 2003-2004 2004-2005 2005-2006 2006-2007
Sources of Funds
Operating Revenue
Rate Revenue $0 $0 $0 $0 $0 $0
Charges for Services 000000
Miscellaneous 000000
Special Assessments 269,362 273,142 327,401 392,160 466,424 540,425
Total Revenues $269,362 $273,142 $327,401 $392,160 $466,424 $540,425
Applications of Funds
Operating Costs
Personal Services $75,070 $90,774 $80,727 $119,483 $165,332 $261,897
Supplies 4,638 3,861 6,158 5,625 13,118 11,315
Purchased Services 11,702 7,819 24,372 25,604 22,736 102,028
Building Materials 234 1,440 697 19,021 782 8,824
Fixed Charges 14,759 21,674 17,770 2,278 21,151 27,499
Loss/Bad Debt Expenses 000000
Depreciation 36,661 94,266 113,911 126,888 181,627 187,453
Total Operating Expenses $143,064 $219,834 $243,635 $298,899 $404,746 $599,016
Operating Income (Loss)$126,298 $53,308 $83,766 $93,261 $61,678 ($58,591)
Non-Operating Revenue (Expenses)
Intergovernmental $0 $0 $0 $0 $0 $15,726
Hookups 00000188,006
Contribution Revenue 0 7,259 284,366 1,401,117 0 1,484,765
Interest Revenue 22,858 13,837 11,277 8,976 36,115 60,203
Debt Service Interest (1,377)(773)(566)(403)(388)0
Gain (Loss) on the sale of Capital Assets 000000
Total Non-Operating Revenue (Expenses) $21,481 $20,323 $295,077 $1,409,690 $35,727 $1,748,700
Net Income (Loss)$147,779 $73,631 $378,843 $1,502,951 $97,405 $1,690,109
Add Depreciation on property and equipment
acquired with capital contributions $0 $0 $0 $0 $0 $0
Increase (Decrease) Retained Earnings $147,779 $73,631 $378,843 $1,502,951 $97,405 $1,690,109
From City's Income Statements
Fiscal Years
SS - 7