Environmental AssessmentB. Environmental Assessment
The proposed Silverbrook Estates Subdivision occupies land sloping to the west toward the
Stillwater River. An unnamed existing drainage swale, which turns into a tributary, bisects
the property from the northeast to the southwest, where steeper slopes occur. This project
proposes to enhance and emphasize this drainage swale, creating gradations of park -like
pond and water features as it nears the Stillwater River. In addition to this waterway, lined
ponds are proposed for the subdivision. The 100-year floodplain and wetland areas currently
exist on -site, adjacent to the Stillwater River.
Geology
A topography map of the project site has been included on the "Preliminary Plat', Reference
Exhibit K for topography. The project site consists of a steady slope down to the west.
According to NRCS soils information, the majority of the site consists of 0-3 percent slopes
with pockets of seven percent slopes. As the bisecting drainage swale approaches the
Stillwater River, slopes range from 30-35 percent.
Our research for this geology study consists of collecting, summarizing and analyzing
geologic information that exists for the area encompassing and adjacent to the project site.
Hydrogeological data (well log reports) are utilized to provide insight as to the general
hydrogeology of the site and surrounding areas. Reference Appendix L.
Investigation indicates subsurface Glacial Lake deposits throughout the entire site. This
includes calcareous fine sandy silt, clayey silt, and minor clay; with thicknesses averaging
100 feet, but up to 270 feet. There are no known unusual conditions regarding installation of
water supply/sewer collection trenches, and underground electric and telephone cables.
NRCS soil maps indicate that Tally soils dominate the site, with patches of Blanchard fine
sand and Kalispell loam. Areas located along the Stillwater River, where the west property
line meets the river, show signs of slumping. To prevent further slumping, development will
remain setback from these areas of steeper Alluvial Land (Ab) soils. Reference Appendix K
for soils information.
According to the "Uniform Building Code," the Flathead Valley is located in seismic Zone 3,
which is rated as moderate to high for probability of seismic activity. Properly constructed
dwellings provide reasonable protective measures against seismic instability.
Roads or streets shown on the plat will be designed with minimum grade changes and
disturbances to the natural terrain. This can be accomplished given the gentle terrain found
throughout the project site and in the general vicinity. Where minimal cuts and fills are
necessary, design criteria will ensure a safe slope from the shoulder and provide for the
return of topsoil cover during seeding and re -vegetation.
2. Surface Water
The site is situated within the Stillwater River drainage system. The surface water follows
the topography from the northeast to the southwest. A culvert under Church Drive brings
surface water from adjacent properties on -site, draining into an unnamed main drainage
swale, turning into a tributary to the Stillwater River. While most of the on -site surface water
also flows into this drainage swale, there is an additional low area on site in the southwest
Silverbrook Estates 18
corner of the development, separate from the main drainage. All surface water on -site then
drains to the west into the Stillwater River. The main drainage swale flows into a small
wetland area just prior to releasing into the Stillwater River. There are no known artificial
water systems on site.
A Wetland Delineation report has been completed by a wetland consultant, PBS&J. This
report indicates that two wetlands and a "wetland fringe" are located along the west portion
of this development. Wetland 1, as defined in the Wetland Delineation report in Appendix F,
consists of 4.3 acres. This wetland has a naturally occurring spring and also receives flow
from the main drainage swale mentioned above. Wetland 2 is located along the northern
most point, where the Stillwater River meets the west property line. Wetland 2 consists of
0.104 acres. The "wetland fringe", a scrub/shrub area, is two acres in size and is located
along the west property line furthest to the south. Wetland mitigation may need to occur just
northeast of where Stillwater Drive crosses Wetland 1. This would be achieved with the
assistance of a wetland mitigation consultant and applicable jurisdictional agency review.
In addition, a Hydraulics Report has been prepared by a hydrology consultant, PBS&J. This
report further describes the hydraulic modeling, the floodplain and stream flow data for the
Silverbrook Estates property. This report has been provided in Appendix F.
Areas along the Stillwater River also include a 100-year floodplain. A Floodplain Report has
been included in Appendix G.
3. Vegetation
The project site has historically been used for crop production, including small grain crops.
As mentioned above, wetlands occur within the project area. Aforementioned, a Wetland
Delineation has been completed by a wetland consultant. This report indicates that Wetland
1 is a mixture of palustrine emergent marsh and scrub/shrub wetland with some shallow
open water and aquatic bed habitat included. Wetland 2 is less diverse and only supports
emergent vegetation. The "wetland fringe" is comprised primarily of shrub species.
Reference Appendix F for the Wetland Delineation. Along the Stillwater River and around
these wetlands are some coniferous tree groupings and grassy meadows. The property's
approximate peak elevation of 3,030 feet has an annual precipitation of 14 to 18 inches. The
average annual precipitation of approximately 15.70 inches was estimated from weather
station # 244558, Kalispell WSO Airport.
The existing native vegetation adjacent to the Stillwater River will be preserved in its near
entirety since development will only occur in areas historically used for agriculture.
Enhancements to the main drainage -way include creating new ponds and enlarging existing
ponds with periodic small waterfalls. Minimal existing vegetation will be removed.
Although most of the property is used for crops, it is assumed that there is the potential for
at least one or more species of noxious weeds to be present on or near the site. Control
methods for noxious weeds will be used following construction activities at the site. Most
likely, there will be chemical control throughout the site along disturbed areas. Other
mechanical methods will be used when necessary, for conditions or when recommended.
A Vegetation and Wildlife Map has been provided as Exhibit J. This map illustrates the
prime areas for wildlife group inhabitation and the major vegetative covers associated with
the Silverbrook Estates property.
Silverbrook Estates 19
4. Wildlife
The Silverbrook Estates property has been established as good wildlife habitat for birds,
waterfowl, and small mammals, including raccoons, skunks, pheasant, turkey and partridge.
This is especially true near the Stillwater River and the wetland areas on the site. The
development plan calls for protecting the key areas of wildlife habitat for these species,
while providing increased water features and vegetation for nesting and shelter. This area is
not known to generally support large numbers of big game (mountain lion, elk, moose, or
black bear), however occasionally these species are found to have visited the site. It is
understood that larger mammals are infrequent visitors. However, Whitetail Deer have been
spotted on site frequently. Evidence of bedding down has been observed. These areas are
proposed to be preserved with minimal disturbance to existing conditions. Bull Trout, an
endangered species, have been sighted in the general area. No other known protected
species inhabit the property. To minimize conflicts between residents and wildlife, individual
waste containers shall be stored within their garages. Animal -proof waste receptacles will be
provided in open spaces or park areas.
Mark Deleray, Montana Fish, Wildlife & Parks (MFWP), Fisheries Biologist, indicated a few
basic concerns regarding fisheries as it relates to stormwater runoff and warm water
situations. In regards to stormwater runoff, adding potential pollutants created by a drainage
system (comprised of curb and gutter, stormdrain inlets, culverts, retention areas, etc.) is
proposed for the development as it flows into the tributary, and eventually into the Stillwater
River. The second concern is the enlarging of water bodies within the spring -contributing
drainage -way, potentially introducing warmer waters into the Stillwater River.
Setbacks along the Stillwater River and erosion can be minimized during road construction
by utilizing Best Management Practices (BMP's). Best Management Practices utilize
controls to minimize possible contamination of surface water. By utilizing BMP's for
construction of internal roads and other infrastructure, water quality will not be compromised.
Tim Their, MFWP Wildlife Biologist, indicated additional concerns related to development
and wildlife impacts. These include the cumulative effect of reduction of small -grain fields
that currently support upland game birds and migrating waterfowl, water supply availability
and specific improvements along the Stillwater River.
With the inclusion of this parcel within the City of Kalispell Growth Policy, it is acknowledged
that growth will spread to this area, reducing the amount of properties being used to
cultivate small -grain fields. However, just north of this property there exists a 240-acre
conservation easement under small -grain agricultural production, that will continually
support wildlife. In regards to water supply for ponds, the existing natural spring will be
maintained. The shape of the pond that it collects in may, however change. Lastly, the
improvements along the Stillwater River will include trails. Minor regrading to accommodate
safe slopes will occur. To adjust these grades, BMP's will be adhered to.
5. Agriculture and Timber Production
The project site generally has a farmland classification of "prime farmland" when irrigated.
Approximately 294 acres of the overall 325 acres have produced alfalfa. Historically this site
has produced alfalfa with a yield of 4.0 to 4.4 tons per acres. Because this land has been
used for farming, it is obvious that the proposed subdivision will remove agricultural land
Silverbrook Estates 20
with existing production capacity. However, the subject property has been included in the
Growth Policy for the City of Kalispell. Therefore, this area is intended to accommodate
future growth, and is anticipated to be annexed. This project area would not create conflicts
with nearby agricultural operations, which are currently producing alfalfa. There is currently
no timber production in the area.
Lot owners and residents of the subdivision will be informed, through the Covenants, that
adjacent land uses may be agricultural, involving agricultural and farming practices, which
can result in dust, animal odors, flies, smoke, and machinery noise (sometimes early in the
morning and late into the evenings).
6. Historical, Archaeological or Cultural Features
The Montana Historical Society and the State Historic Preservation Office were contacted
regarding historical and cultural issues for the property. The Montana Historical Society has
responded with a letter that indicates that no significant cultural resources have been found
through preliminary searches. However, Damon Murdo, Cultural Records Manager,
recommended that if any development should be planned for the Stillwater River area, that
the Applicant be careful to not impact potential significant sites. If any prehistoric cultural
material is encountered during subsurface disturbance phases of the proposed work,
construction should be suspended and a professional archeologist be notified. At this time,
no known historical, archaeological or cultural features are located in the development area.
With respect to surrounding cities, towns, developments, or homes, the proposed
subdivision is bordered by agricultural property to the south, US Highway 93 to the east, a
conservation easement to the north, and the Stillwater River to the west. Local zoning
regulations along with PUD modifications will be utilized for ultimate build -out of the
subdivision. Hence, visual impact as a result of this development is minimal with respect to
roads, adjacent developments, or any other public facilities. Roads are planned to affect the
natural terrain as little as possible with grades and alignment designed to reduce cuts and
fills. All excavated areas will be reseeded and returned to the natural vegetation. Utilities are
anticipated to be underground with boxes and structures positioned out of sight as much as
possible or designed to fit into the character of the land.
7. Sewage
The developer will extend a city sanitary sewer mainline to the project area along US
Highway 93. The proposed City of Kalispell sanitary sewer extension location, diameter and
capacity are being determined in a Preliminary Engineering Report currently being prepared
by the Civil Engineering consultant. The gravity collection main size, lift station capacity and
force main are being sized based upon the contributing basin population projections for a
20-year planning horizon, as required by the City of Kalispell and MDEQ. The preliminary
engineering design will be reviewed by the City of Kalispell, MDEQ and MDOT.
The Applicant will work with the Kalispell Public Works personnel in the design and location
of all sanitary sewer lines including possible improvements of existing sewer lines at those
points of connection. Morrison Maierle and HDR Engineering are currently working on
design of City of Kalispell's wastewater treatment plant, Phase I expansion project.
Silverbrook Estates 21
All sanitary mainlines within the development will follow road systems or utility easements,
and would be owned and maintained by the City of Kalispell. The design and construction
will be the Master Developer's responsibility.
The Applicant anticipates two lift stations will be required for this development. Locations are
undetermined at this time. The Applicant intends to provide sewer mains with gravity flow
within the development, ultimately to lift stations as required.
The layout for Silverbrook Estates Subdivision represents approximately 586 residential lots,
consisting of one -quarter to one-half acres in size, with an abundance of open space.
According to the 2000 Census, Flathead County data reflects approximately 2.48 people per
dwelling unit. Using 100 gpd/person for wastewater generation, this corresponds to 248
gpd/dwelling unit. Ultimately, Silverbrook Estates may generate 145,328 gpd (586 dwelling
units x 248 gpd/dwelling unit). The flow estimation will be defined by MDEQ requirements.
The commercial area will consist of 12 buildings. Since there is a projected build -out over
the next few years, specific lot uses are unknown and water demand is difficult to predict.
For planning purposes, the Applicant anticipates a conservative generation per building lot
to be 500 gpd. The anticipated demand at full occupancy is approximately 6,000 gpd for the
commercial lots ((500 gpd/lot) x (12 lots) = 6,000 gpd).
The anticipated demand at full occupancy for Silverbrook Estates is approximately 151,328
gpd for this PUD (145,328 gpd + 6,000 gpd). This number will ultimately be defined by
MDEQ requirements.
Currently, the Applicant is planning for two phases for the proposed Silverbrook Estates
Subdivision. This would reflect 285 residential lots for Phase 1 to be constructed summer of
2007. The summer of 2010 is the estimated completion for Phase 2 and includes 301
residential units.
No industrial wastewater is planned as part of this development.
Moore Engineering has prepared a Preliminary Engineering Report that presents and
clarifies issues regarding site drainage and proposed sewer facilities. This report has been
provided as Appendix H.
8. Water
City water mains are also proposed to be extended to the project area along US Highway
93, at the Master Developer's expense. The Applicant is working with the Kalispell Public
Works Personnel in the design and location of all city water and fire -protection needs. The
proposed water main extension location and diameter is being determined in a Preliminary
Engineering Report, which is currently being prepared. The water line diameter is being
sized based upon the contributing basin population projections for a 20-year planning
horizon, as required by Kalispell and Montana Department of Environmental Quality
(MDEQ). The preliminary engineering design will be reviewed by the City of Kalispell, MDEQ
and MDOT.
The Applicant is proposing a new well and pump house within this development for the
purpose of supplementing the city water system and satisfying water looping requirements.
Silverbrook Estates 22
The Subdivision will then connect into this City water main extension. Within the
development, the water mainlines will also generally follow the road systems and will be
designed to meet City of Kalispell standards. The design and construction of all water mains
will the developer's responsibility. However, all water mainlines extending to the
development and then within the development will be owned and maintained by the City of
Kalispell.
The consumptive water demand is consistent with the anticipated wastewater generation.
The Applicant also has water rights from the Stillwater River for 12,000 gpm from an
existing pump previously used for irrigating cropland. This will be used for irrigating
open space, parks and common areas. These water rights and source will also be
used to fill and replenish the ponds and water features within the Subdivision.
Ground water well logs have been provided for the area and are located in Appendix
L.
9. Solid Waste
Solid waste collection may be serviced initially by a private hauler and then eventually by
city Public Works, with disposal in the Flathead County Solid Waste Facility. Evergreen, a
private hauler, has been contacted and the Applicant is awaiting responses. However, solid
waste disposal will meet the requirements of the Department of Environmental Quality.
Residential solid waste is anticipated to be collected from individual containers located at
the street of each residence. With the exception of collection days, the individual containers
shall be stored out of view. Commercial solid waste is anticipated to be collected at central
trash container areas within the Neighborhood Commercial area, with individual containers
placed near the lot, but within the district parking areas.
10. Drainage
A drainage system comprised of curb and gutter, bridges, storm drain inlets, and culverts is
proposed for the internal roads. All roads within the subdivision will be paved. Drainage
facilities will be designed and installed to accommodate a two-year storm event in
accordance with standard stormwater mitigation processes. The system will also be sized to
allow for a 100-year event in accordance with Montana Department of Transportation
standards. A detailed storm drainage plan will be submitted for review and approval to City
of Kalispell. Runoff will be determined using current regulation for precipitation / frequency
values.
Roads or streets will be shown on the plat and will be designed with minimum grade
changes and disturbances to the natural terrain. This is due to the gentle terrain found
throughout the construction area. Where minimal cuts and fills are necessary, design criteria
will ensure a safe slope from the shoulder and return a topsoil cover for seeding and re -
vegetation.
The existing drainage system within open areas will remain intact with grading kept to a
minimum, maintaining existing drainage patterns. The main drainage swale will be
enhanced, creating areas of naturalized pooling water and small water falls. Some pond -
lined water features, not directly connected to the main drainage swale, may act as
Silverbrook Estates 23
detention facilities. The difference between pre -development and post -development storm
water volume shall be used for on -site detention basin design.
Erosion control can be minimized during road construction by utilizing Best Management
Practices (BMP's). Best Management Practices use controls to reduce possible
contamination of surface water. Erosion control plans will be designed and reviewed in
accordance with MDEQ requirements.
Moore Engineering has prepared a Preliminary Engineering Report that presents and
clarifies issues regarding site drainage and proposed sewer facilities. This report has been
provided as Appendix H.
11. Roads
This subdivision will inherently generate more traffic along Church Drive. Montana
Department of Transportation (MDOT) is currently redesigning the intersection of Church
Drive and US Highway 93, as well as the 750 linear feet west from the interchange along the
project site. The Applicant has been in contact with MDOT for coordinating with our
proposed project. Silverbrook Estates' Master Developer intends to annex the property and
half of the 60-foot right-of-way of Church Drive along the property. The Master Developer
plans to finance the design and construction of the rest of Church Drive west of the 750 foot
extension to the intersection of Church Drive and Prairie View Road, to county standards.
It is proposed that lots within the subdivision shall not have direct access onto an existing
arterial road. The lots will have access directly off of the proposed interior roads. No access
will be required across private property in residential areas. The commercial area is currently
being evaluated for these issues. The Montana Department of Transportation (MDOT) has
indicated they will grant access onto US Highway 93 as shown on the plan, with approach
permits being obtained following Preliminary Plat approval.
The road system network throughout Silverbrook Estates will meet or exceed the City of
Kalispell standards, with minor modifications. The design and construction of the road
system will be financed by the Master Developer. The road system will eventually be
dedicated to the City. Future maintenance of these streets will be the responsibility of the
City.
A "Preliminary Traffic Impact Study" has been prepared to specifically evaluate existing and
proposed daily traffic needs adjacent and within the development. Reference Appendix I
for the "Preliminary Traffic Impact Study."
12. Emergency Services
Upon annexation, the project site will be serviced by the Kalispell Fire Department. Randy
Brodehl has been contacted about serving this development. To accommodate future
growth of the area, an approximately 2.5 acre parcel will be dedicated to the City of Kalispell
Fire. This parcel is conveniently located along Church Rd on the west end for quick and
safe access. The Fire Department plans to use this parcel for a well site and fire station.
Until the fire station parcel is operational, the phasing and timing of this project will be
closely coordinated to ensure proper response time and available personnel are available.
Response to the site is dependent on several factors, including, but not limited to the
Silverbrook Estates 24
distance from the scene, weather, road conditions, and availability. As a component of this
development, the Applicant will extend city water services to the project area. Fire hydrants
are proposed to connect into this service as well as commercial areas will be required to
install fire suppression sprinkler systems. The pressure required to operate, and the
locations of these systems will be adequate and will meet all required local, state and
federal requirements.
The Applicant received a response letter from the Kalispell Police Department and is
currently working with the Kalispell Police Department to discuss law enforcement concerns.
Ambulance and EMS service will be provided by the City of Kalispell Fire Department.
Medical services will be provided by the Kalispell Regional Medical Center, which is located
five miles from the project site.
13. Schools
Kalispell Public Schools has been contacted about their capacity, facilities, personnel, and
bus routes, to accommodate the increase in students that may attend the schools from
Silverbrook Estates. On September 20, 2006, discussions with Superintendent Darlene
Schottle identified potential strategies to lessen the impact of providing service to these
additional attendees. With the new high school located at West Reserve and Stillwater, her
concerns basically involved elementary age children, primarily kindergarten and first grade.
Instead of adding to an existing facility, one creative idea discussed is to potentially provide
an area within the development for a 2,500 to 3,000 square foot facility (2-3 classrooms),
similar to a preschool, where teachers could conduct satellite classes. This was one of many
ideas discussed. The Applicant will continue discussions with the School District. Darlene
did indicate whether or not the School District #5 will be able to accommodate the projected
300 additional attendees. This number is estimated by using 0.5 students per residence.
14. Economic Benefits
The expertise of an economic consultant was retained for evaluating the economic benefits
and impacts of the Silverbrook Estates Subdivision. Dr. Ann L. Adair, Senior Economist,
from the MSU Center for Applied Economic Research evaluated the commercial impact and
the residential market. Reference this document in Appendix J.
The present tax classification and designation for the subject property is "agricultural rural'
with a tillable, grazing designation and one -acre farm site improvements. The change of
classification to residential urban and commercial urban will greatly elevate the tax potential.
The property of Silverbrook Estates in 2005 generated approximately $12,000 in general
taxes. The current general tax generation under the existing classification will be provided
as well as the anticipated general tax potential for the fully developed subdivision. There are
no foreseen economic disadvantages to the community that will be caused by this
development.
15. Land Use
The current and historical use of this land is agricultural. As in compliance with the proposed
Growth Policy Amendment, this development is proposing various single family residential,
multi -family, and commercial land uses and concurrently seeking annexation as a part of
this application.
Silverbrook Estates 25
The adjacent land uses include a 240-acre conservation easement, agricultural, and arena
(north), US Highway 93 (east), Stillwater river and farmstead (west), and agricultural
residence (south). Access for these adjacent land uses is simplified with the proposed
development. This project is maintaining no access connections to the west. However land
uses to the west and north will benefit from since the Applicant proposes to make
improvements along Church Drive, from US Highway 93 along the project site, and
extending approximately one mile to the intersection of Church Drive and Prairie View Road.
City of Kalispell collector road widths are proposed to be installed for Church Drive. The
overall design of Silverbrook Estates allows for future connection to the southern property,
which is currently under agricultural residential designation. However, discussions with that
property owner indicates it is currently under subdivision redevelopment.
Lot owners and residents of the subdivision will be informed through the Covenants, that
adjacent uses may be agricultural, involving standard agricultural and farming practices,
which can result to dust, animal odors, flies, smoke, and machinery noise (sometimes early
in the morning and late into the evening).
By following the guidance of the Kalispell Growth Policy, the community needs are being
served. The commercial area is located for easy access at the newly redesigned intersection
of US Highway 93 and Church Drive. The residential town home then buffers the
commercial from the single-family residential. There are currently no existing developments
of this nature in the area. There are no known health or safety hazards on or near the
subdivision, nor any nuisances being created by the proposed development.
16. Parks and Recreation Facilities
The open space within the development is proposed for passive activities. It will be
accessible for use by members of Silverbrook Estates and residents of the City of Kalispell.
Areas adjacent to US Highway 93, the main drainage way, the Stillwater River area, and
pocket -parks within residential areas will serve as recreation areas. A corridor along US
Highway 93 has been proposed, which would include berming, water -features, landscaping,
and a pedestrian/bike path to provide recreation and access for the Kalispell community as
well as Subdivision residents. This pathway will have a loop, to bring users from the highway
corridor, through the community, and along the main drainage way.
The meandering main drainage way, with enhanced water features, spans the entire
Subdivision and will serve as the main recreation corridor. Moving from east to west, the
character of this corridor will transition from a manicured pastoral park to a natural park.
Pedestrian pathways serving subdivision residents will provide access to two pocket parks,
located within residential areas.
Silverbrook Estates is proposed to have all open space to be designed and installed, at the
expense of the Master Developer, and maintained by Property Owners Association as
mentioned in the "Common Area Management plan." Reference Exhibit C: Land Use Map
for open space area locations.
17. Utilities
Utility companies have been contacted concerning providing service to the Subdivision.
Flathead Electric Cooperative is anticipated to provide both gas and electric service in
accordance with applicable Montana Public Service Commission rules and regulations.
Silverbrook Estates 26
Telephone service will be furnished by Century Tele. Cable will be provided by Bresnan
Communications. The proposed location of utilities will be coordinated with the respective
utility companies. It is the Applicant's intent that all of these utilities be located underground
where feasible and within rights -of -ways or easements. Installation completion date for each
has been discussed in the phasing discussion. All appropriate utility easements will be
provided along lot lines and roads in accordance with City of Kalispell subdivision design
requirements. All proposed easements will be clearly delineated on the plat.
Silverbrook Estates 27