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TOWN OF COALDALE
______________________________________________________________________________________________________________
COTTONWOOD ESTATES
AREA STRUCTURE PLAN
- October 31, 2005 -
BYLAW # 547-P-06-05
2
TABLE OF CONTENTS
______________________________________________________________________________________________________________
COTTONWOOD ESTATES AREA STRUCTURE PLAN
Page
1) Purpose.........................................................................................................................................................6
2) Location, Area & Ownership..........................................................................................................................6
3) Area Structure Plan Goal............................................................................................................................7
4) Area Structure Plan Objectives.....................................................................................................................7
5) Existing Conditions & Development Considerations.....................................................................................9
a) Site Evaluation..................................................................................................................................... 9
i) Topography.......................................................................................................................................9
ii) Irrigation Works.............................................................................................................................10
iii) Rights-of-Way................................................................................................................................11
(a) Trunk Sewer Facilities.........................................................................................................11
(b) Treated Water.......................................................................................................................11
iv) Other Utilities.................................................................................................................................12
(a) Electrical Distribution.........................................................................................................12
(b) Telephone & Cable.................................................................................................................12
(c) Natural Gas.........................................................................................................................13
v) Roadways and Access.....................................................................................................................13
(a) Town Streets........................................................................................................................13
(b) Highway 845......................................................................................................................13
(c) Future Connection to Highway 3.........................................................................................13
(d) County of Lethbridge Township Road 9-1...........................................................................14
b) Land O'Lakes.......................................................................................................................................14
c) Adjacent Residential Development........................................................................................................16
d) Natural Features..................................................................................................................................16
6) Planning Context......................................................................................................................................18
a) Town of Coaldale Municipal Development Plan....................................................................................18
3
b) Level of Planning Detail.......................................................................................................................18
7) Land Use Concept.......................................................................................................................................19
a) Overview Of Proposed Land Uses...........................................................................................................19
i) Residential Development.................................................................................................................19
(i) Housing Demand...........................................................................................................19
(ii) Neighbourhood Character...............................................................................................20
(iii) Lot Types.......................................................................................................................21
1. Estate Lots...............................................................................................................20
2. Large Lots................................................................................................................21
3. Enhanced Setback Lots............................................................................................22
4. Standard Lots.........................................................................................................22
5. Multi-unit Dwelling Sites.......................................................................................22
(iv) Lane Accessed lot Demand............................................................................................23
ii) School Site.....................................................................................................................................23
iii) Parks, Open Space & Walkways....................................................................................................24
b) Road Network......................................................................................................................................26
i) Roadways & Access points.............................................................................................................26
(1) Access to Development Area.......................................................................................................26
(a) Fairway Dr., Twenty- second Street & Twenty-Fourth Street..............................................26
(b) Twentieth Street/ SR845...................................................................................................27
(c) County Township Road 9-1................................................................................................28
ii) Circulation Within Development Area............................................................................................28
(1) Road Hierarchy........................................................................................................................28
(2) Major Collector Roadways.........................................................................................................29
(3) Minor Collector Roadways........................................................................................................30
(4) Local Roads..............................................................................................................................31
(5) Pathway System......................................................................................................................31
c) Servicing Concept & Phasing...............................................................................................................32
i) Sanitary Sewage Collection...........................................................................................................32
ii) Water Supply & Distribution System............................................................................................33
iii) Storm Water Management System...............................................................................................33
iv) Shallow Utilities............................................................................................................................35
v) Domestic Irrigation.........................................................................................................................36
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d) Sidewalks, Street Lighting and Road Standards...............................................................................36
e) Potential Staging................................................................................................................................37
f) Sustainable Community Development.................................................................................................39
g) Architectural Control............................................................................................................................41
h) Community Mailbox Locations............................................................................................................42
i) Alignment With Municipal Development Plan....................................................................................42
j) Consultation Process............................................................................................................................43
i) Open House....................................................................................................................................43
ii) Town Administration, Planning and Engineering Advisors........................................................44
iii) St. Mary's River Irrigation District...............................................................................................44
iv) Alberta Transportation and Utilities..............................................................................................44
v) Land O'Lakes Golf Course Management.......................................................................................44
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Appendices
1.
..........................Land Ownership Information
2.
.....................................Master Servicing Plan
3.
..................Potential Land Use Classifications
4.
.......................... Gateway Design Alternatives
5.
.......................................Street Cross Sections
6.
....................................... Potential Lot Layout
Maps
Figure 1
...................................................General Location
Figure 2
...................................................Land Ownership
Figure 3
..................................Constraints & Opportunities
Figure 4
................................................Existing Land Use
Figure 5
.................................................Existing Contours
Figure 6
..................................................Land Use Concept
Figure 7
........................................................Road Network
Figure 8
.......................................................Design Grades
Figure 9
.....................................................Sanitary Sewer
Figure 10
................................................Water Distribution
Figure 11
........................................................Storm Design
Figure 12
................................................ Potential Staging
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1) Purpose
Cottonwood Area Structure Plan has been produced in accordance with Section 633 of the Municipal
Government Act to create a framework for the future subdivision and development of a new
neighbourhood in south-central Coaldale. It is thus intended that the plan identify and provide for a
range of development opportunities on previously undeveloped agricultural land.
2) Location , Area & Ownership
Blair Frache, through his company, 324700 Alberta Limited, is the registered land owner of
Cottonwood Estates. Wholly located within the Southeast Quarter of Section 10, in Township 9,
Range 20, West of the 4th Meridian (10-9-20), the development area contains 150.76 acres (61 ha.)
more or less(please refer to Figure 1).
Land title exceptions include property taken for irrigation purposes (8 acres or 3.25 ha.) and road
widening (1.24 acres or 0.502 ha.) In addition, there have been utility rights-of-way granted to the
Town of Coaldale, the County of Lethbridge and Canadian Western Natural gas Company Ltd (Please
refer to Figure 2). St. Mary River Irrigation District has placed an irrigation order/notice indicating
that the property has irrigation rights associated with it (please refer to Appendix #1).
7
3) Area Structure Plan Goal
The Goal of the Cottonwood Area Structure Plan is to establish a strategic framework that will enable the
development of a neighbourhood of enduring quality.
4) Area Structure Plan Objectives
Cottonwood Estates Area Structure Plan will respond to the needs, issues and requirements identified
by 324700 Alberta Ltd., the Town of Coaldale and those agencies, organizations and individuals
having an interest in the planning of this area. The subdivision will evolve over a period of time to
become a fully integrated neighbourhood within Coaldale.
To facilitate neighbourhood integration, this Area Structure Plan will endeavour to:
1) guide the agricultural to urban development transition in an orderly and economical manner;
2) mesh the development pattern and circulation system with that of surrounding, existing
development;
3) create a residential neighbourhood that includes a mix of dwelling types and densities;
4) incorporate other compatible land uses as required;
5) establish the supporting internal transportation network and public utilities;
6) institute a storm water management system that responds to both public utility and amenity
functions;
7) provide and distribute open space and a trail system that connects this neighbourhood with
adjacent neighbourhoods;
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8) utilize water from the SMRID irrigation system for park and lawn watering purposes rather
than treated Town water;
9) create distinctive residential enclaves by establishing design themes and development
standards, implemented through architectural controls and the land use bylaw;
10) propose a development phasing system;
11) design in greater detail, the potential first stage of the first phase and the balance of the
property in a more conceptual manner;
12) provide sufficient flexibility to accommodate design adjustments which respond to future
market conditions, in keeping with community goals;
13) describe an implementation program that guides future land use classification and subdivision
9
5) Existing Conditions & Development Considerations
a) Site evaluation
Mr. Frache is nearing completion of a new home in the southwest corner of the property which will be easily
incorporated into the future subdivision design. The former Kasner home site occupies a tree-lined portion
of the northeast corner of the property. An abandoned farmstead contains some hay storage and newer
grain bins but otherwise, the balance of this area is cluttered with obsolete farm equipment, several old
buildings, corrals, and a small livestock watering pond. Mr. Frache is currently in the process of cleaning
up this area.
Currently, a majority of the site is used for agricultural purposes and a small pasture lies north of the
minor irrigation canal which is the water delivery conduit for some water users east of Highway 845. The
remainder of the site, south of a farm irrigation ditch, has most recently produced hay and grain crops.
Several other features on or adjacent to the site must be taken into account as the land is developed in the
future (please refer to Figure 3 & 4).
i) Topography
The natural topography of the development area has been altered to facilitated irrigation farming. Although
relatively flat, the land does slope from west to east and the changes approximately five meters in elevation.
The topography is further influenced by irrigation works on or adjacent to the property (please refer to Figure
5).
10
ii) Irrigation Works
Entering the site at the northwest corner and stretching along the entire northern property line, a
30 meter wide St. Mary River Irrigation District (S.M.R.I.D.) canal (IRR 126 Y & IRR 56 L) is
the most prominent irrigation feature. This location is also the official delivery point to the quarter
section and three structures along the canal control water flow. The canal is a built-up dike type of
structure and its back-slope will be a consideration in determining future lot dimensions and
setbacks due to anticipated storm water and snow melt run-off. Currently, the flow structure/turn
out mid-way along the northern property line, near 22nd St., is used by pedestrians to cross
canal.
The width and depth of the canal would require bridging structures at 22nd Street and at Fairway
Drive which are two potential crossing locations. These would also be logical crossing locations for
other utility service connections. A smaller delivery ditch that is currently used to fill the stock
watering dugouts in the old farmstead and provides service delivery for two parcels east of
Highway 845.
There is also a ditch-rider service road along north side of canal which may be a possible feature in
the future open space system in this part of town.
The cumulative effect of these irrigation works will have a bearing on future land use, access,
utility extensions and storm water management of the development area.
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iii) Rights-of-way
(a) Trunk sewer facilities
Trunk sewer facilities in a right-of-way, which services the Land O' Lakes subdivision, traverse
the site in an east-west direction in alignment with 30th Avenue, east of the development area.
With a fixed location, this major utility lies within a 10 meter sewer line (right-of-way Plan
#851 0909). The linear nature of this right-of-way presents a constraint in the subdivision
design since it cannot be relocated and must be preserved in a road or other linear site element.
However the presence of the sewer within the site can also be considered an asset since it has
sufficient capacity to service the development area.
(b) Treated water
Treated water flows through a pipeline conveying water from the City of Lethbridge to Coaldale
and the McCain potato processing plant east of Town, near Chin. This pipeline is situated in a
right-of-way (plan #001 0145) which varies in width from 10 to 20 meters. The pipeline enters
the development area at the southwest corner through a 10 meter right-of-way and proceeds
easterly along the southern property line to the midway point where it turns north. The pipeline
then becomes 20 meters in width in a north-south alignment which extends to the midpoint of
the ¼ section. The right-of-way then turns to the east, is reduced in width to 10 meters again
and runs immediately parallel to the 10 meter sewer line right-of-way. The water pipeline right-
of-way extends to Highway 845 and aligns with 30th Avenue to the east.
12
Together with the 10 meter sewer right-of-way, the combined 20 meter fixed-location right-of-
way creates a further constraint in the subdivision design as it too must be preserved in a road
or other linear site element.
Again, as with the sewer, the location of potable water on-site is an asset for developing the site
since there is sufficient capacity within this waterline to satisfy both the domestic and fire flow
requirements.
iv) Other utilities
Several other public utility installations or features are situated on or near the plan area that
will provide service connections or otherwise influence site development.
(a) Electrical distribution
Electrical distribution in the area is supplied by Fortis Alberta United Inc. with power lines
constructed along the northern, southern and eastern edges of the development area.
(b) Telephone cable
Telephone cable is buried along the east side of the development area as well as within developed
areas to the north, east and west of the development area.
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(c) Natural gas,
Natural gas through an ATCO Gas pipeline is currently situated just west of the S.M.R.I.D.
turnout on the northern site boundary as well as in developed areas to the north, west and east.
v) Roadways and Access
(a)
Town Streets
Currently, no Town streets extend into the development area, however several streets provide
openings that would facilitate future access.
b) Highway 845
Highway 845 becomes Twentieth Street north of the main S.M.R.I.D. canal, forms the easterly
site boundary. Two further access points intersect with 20th Street ; both of which where the old
farmstead is located. Highway 845 is posted as a 50 km zone within town limits and is a
designated truck route at the present time. With these factors in mind, longer residential lots or
deeper setbacks are design and development considerations.
Both existing and potential future access points are controlled by Alberta Infrastructure and
Transportation since this is a Secondary Road in the Provincial highway hierarchy.
(c) Future Connection to Highway 3
Functional Planning for Highways 3 and 845, conducted by McElhanney Consulting Services
Ltd. for Alberta Transportation and Infrastructure and the Town of Coaldale in 2004, indicated a
future connection between 30th Avenue to 30th Street and Highway 3 through the development area.
14
This road, if constructed would have a negative effect on the future residential neighbourhood
envisioned for the Cottonwood Estates area. It would not be reasonable to expect that costs
associated with constructing this potential Town arterial roadway would be borne by the developer.
(d) County of Lethbridge Township Road 9-1
Township Road 9-1, situated along south boundary of the plan area, is a narrow,"forced road" that
is also the Town-County boundary. This paved County road is somewhat of a crescent as it heads
west, then south and then east again, where it becomes Township Road 9-1 and returns back to
Highway 845.
The road provides access to an abandoned farmstead, used for apiary purposes and an operational
farmstead with associated agricultural land to the south of the development area and a vehicle
wrecking operation at the same location.
b) Land O'Lakes
Land O'Lakes residential subdivision and golf course lies directly west of the development area.
There are several aspects of Land O'Lakes that will influence the manner in which Cottonwood
Estates will be planned and developed.
As previously mentioned the potential for access to and from Fairway Drive is a significant design
consideration because this location is ideal for both an appropriately situated access and an
aesthetically pleasing entrance into the subdivision. The Town and Land O'Lakes should use this
15
access point to replace the one currently indicated as entering at the southwest corner of Cottonwood
Estates as an extension of the southeast arm of Fairway Drive.
The expanse and views created by a golf course contribute to a very desirable real estate situation.
Land O'Lakes Golf Course was planned and designed to maximize residential exposure to the park-
like quality it provides. This situation extends to land within Cottonwood Estates that is adjacent
to the golf course, particularly along most of the west site boundary.
While the golf course provides an attractive feature, it also presents a design constraint. Fairways
14 and 15 can be challenging for some golfers whose golf balls often extend a considerable
distance in the adjacent field to the east. Future lots along these fairways will thus likely have to
be somewhat deeper to overcome the menace posed by errant golf balls. A barbed wire fence
currently demarcates the property line.
Other golf course features to be aware of as future lot layouts are considered include the irrigation
pump house about 2oometers north of the southerly ¼ section line near the west boundary of the
development area. The tee-box for the 16th fairway is situated near the southwest corner of the
development area close to where Fairway Drive has been designed to be extended eastwards. This is
also the nearest location of Land O'Lakes homes to future Cottonwood development.
16
c) Adjacent Residential Development
Two blocks of various sized and shaped lots, face 24th Avenue. Several lots, near the northwest
corner of the development area also face either 25th Avenue or 23rd Street, both of which truncate
where they intersect each other. An R-2 zoned area comprised of 6 villa-like semi-detached
dwellings is situated between 24th and 25th Avenues and 22nd and 23rd Streets as well. Three
newer single detached dwellings facing Fairway Drive are positioned near the entrance to Land O'
lakes where a potential access point to the development area is situated.
Most of these lots are physically separated from the plan area by the S.M.R.I.D. canal and a town
lane. Varying from 30 meters in the laneless areas to 38 meters where there is a lane, this
separation currently functions somewhat like a combined green strip, walkway and wetlands area
along the canal. Several lots in this area have detached garages that utilize the lane for access as
does the Town solid waste collection operation. These lots are lower than the top of the irrigation
canal but the distance from the canal and local grades tend to compensate for potential flooding
events.
d) Natural Features
Natural features In and around the development area are limited as virtually all existing wetland
or tree growth can be attributed to the presence and availability of irrigation water. Marsh-like
vegetation is found on either side of the S.M.R.I.D. canal and a lateral ditch that winds across the
development area and the old farmstead ponds.
17
There is a character cottonwood tree, for which the subdivision is currently named, near the
northwest corner along the winding irrigation lateral. This old tree is an existing focal point as
evidenced by the informal pathways that lead to it from the minor canal crossings at Fairway
Drive and at 22nd Street. There is also a discontinuous tree stand of old Cottonwoods around the
old farmstead. These old Cottonwoods while providing character to the area, are nearing the end of
their life span however subdivision design and development activity should be carefully
undertaken to preserve them as long as possible.
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6) PLANNING CONTEXT
a) Town of Coaldale Municipal Development Plan (M.D.P.)
In addition to the requirements of the Municipal Government Act, this Area Structure Plan has
considered the Town of Coaldale Municipal Development Plan and incorporated those applicable
features or requirements that pertain to the long-range, detailed planning of the Cottonwood
Estates development area.
Among those features of the Coaldale M.DP. that have been included are the following;
- direction of community growth
- population change and structure
- construction activity
- housing trends
- economic development influences
- transportation routes
- specific land use requirements
- open space requirements and trends
- urban and rural interface challenges and opportunities
b) Level of Planning Detail
In the preparation of an Area Structure Plan, The Town of Coaldale requires a level of detail that will enable
Town staff and its planning and engineering advisors to evaluate the proposal as if it were at a detailed
"Outline Plan" level. At this level of planning, the transportation circulation system together with the
master servicing planning for storm water management, sanitary sewer collection, water distribution is
well advanced.
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7) LAND USE CONCEPT
The Land Use Concept described below is graphically illustrated on Figure 6.
a) Overview Of Proposed Land Uses
i) Residential Development
(i) Housing demand
Housing construction in Coaldale has hovered around 30 dwelling units per year in recent years, while
reaching 38 units in 2004. Within the development area, Cottonwood Estates has the land base to
help satisfy long term housing needs in Coaldale. Future new home construction will be subject to a
variety of factors. Demographic change will influence both the number of dwelling units and the
number of persons per dwelling unit as the seniors' population increases, for example. Low interest
rates, a healthy agricultural sector and other economic factors including new job creation, in and
around the community, can be expected to continue to influence the residential market in Coaldale.
Continued growth and development within the City of Lethbridge may also influence the housing
market in Coaldale.
Cottonwood Estates will be designed to respond to the housing needs of both current and future
Coaldale citizens. Single detached and multi-unit dwellings will reflect Coaldale's current and
anticipated housing mix which generally ranges between 90%-95% single detached and 5%-10% multi-
unit. Based on potential subdivision layouts, Cottonwood Estates would create between 450 and 500
dwelling units. The gross housing density of the development area would thus be approximately 7
units per hectare or about 3 units per acre. If a School site is not required, the housing density would
20
marginally increase to 8 units per hectare or just over 3.1units per acre. Based on an average of 3
persons per dwelling unit, the population that could be accommodated in the development area would be
in the range of 1350 to 1500. Once roads, utility rights-of-way, open space and other land uses are
factored in, the net density would be between 4.2 and 4.5 units per acre (10.4 and 11.1 units per
hectare).
(ii) Neighbourhood Character
Low density, single dwelling unit development will predominate within the development area.
Although there will be four general ranges of lot size, subdivision design is somewhat flexible so that
lot sizes can more easily be adjusted for anticipated future conditions. Generally, lot sizes will be
larger than comparable lots in other parts of town. This will contribute to the spacious experience of the
overall development.
Storm water management requirements and utility rights-of-way have produced further opportunities
to create open spaces adjacent to significant amounts of residential development. The cumulative effect
of these open spaces will contribute to a more park-like character throughout the development area.
Even though Cottonwood Estates will be a low density neighbourhood, a majority of the subdivision is
intended to be laid out with an east-west street orientation which will enhance solar access should
homeowners wish to take advantage of the opportunity thus provided.
21
Further neighbourhood enhancement will result form the creation of gateways at entrance locations,
especially near Fairway Drive and at 20th Street (Highway 845). Creation and landscaping of
roadway medians and boulevards will further enhance the atmosphere of the new neighbourhood.
(iii)
Lot Types
1. Estate lots
Estate lots are intended to provide spacious sites to satisfy upper-end housing demand in Coaldale.
Lots will range between seventy-five to one-hundred meters in depth. Deeper lots are also intended to
compensate for errant ball-flight from adjacent golf course tees and fairways. Lot widths will be
determined at the tentative plan stage but are likely to vary somewhat to allow for marketing
flexibility. Moved-in buildings would not be desirable as a discretionary use in this area. Building
setbacks will be an important consideration in this district to ensure that errant golf-balls are avoided
as much as practical.
2. Large lots
Large lots are intended to provide sizeable sites to satisfy upper-end housing although on smaller than
estate size lots. These lots range between sixty and eighty meters in depth and are located adjacent to
the S.M.R.I.D. canal along the northern edge of the development area. These lots are relatively deep to
take advantage of the amenity value of the canal and to assist in the drainage attributable to canal
back slope and to provide space for a potential underground domestic irrigation pipeline. Although
possible as a discretionary use, "moved-in buildings" would not be desirable as a discretionary use in
the plan area.
22
3. Enhanced setback lots
Enhanced setback lots will be those backing onto Highway 845 or other locations that warrant an
enhanced setback. These lots will likely be in the range of fourty-five to fifty meters in depth. This
extra depth is intended to provide added sound attenuation value. Lots that back onto the County of
Lethbridge township road will also in the fourty-five meter depth range. This depth will provide an
extra setback that may possibly be required for road widening or utility extensions in the future.
Unless a new land use district is created to account for the proposed lot dimensions, these lots would
fall within the Residential R-1A District of Land Use Bylaw 469-P-10-00. If the land is needed for
road widening, it should be acquired at the time of subdivision.
4. Standard lots
Standard lots would also fall within the Residential R-1A District of Land Use Bylaw 469-P-10-00.
Within the development area, these lots are intended to be fourty meters deep, which is six and one-half
meters deeper than the Bylaw minimum.
5. Multi-unit dwelling sites
Multi-unit dwellings will be dispersed throughout the development area rather than concentrated in one
or two locations. Multi-unit residential may consist of plus fifty-five, adult villa and senior sites; a
possible seniors village as well as family-oriented housing.
Sites will be conveniently located and strategically placed near collector roads and open space.
Designated multi-unit sites in the Area Structure Plan will be designed with sufficient flexibility to
enable conversion to lower density residential to respond to market conditions. If this occurs,
23
replacement multi-family sites will be considered elsewhere in subsequent phases of development on low
density "swing" site locations in order to maintain the appropriate housing mix. Multi-unit dwelling
lots would likely be classified Residential Multi-family R-2.
(iii)
Lane accessed lot demand
Laned-accessed lot demand within the development area is not expected be as great as in other parts of
town since lots will be large thus reducing the need for secondary access. Nevertheless, Cottonwood
Estates will provide a mixture of laned and laneless opportunities to enhance marketing options.
ii) School Site
A school site, likely for a public elementary school, of between 4 and 5 hectares is planned north of 30th
Avenue between 20th Street and the north-south collector road to the west. The school is expected to be
necessary within 5 to 10 years. It is not expected that there would be a direct access to the school site
from 20th Street.
If required, storm water detention could be provided on the school site. This facility would be a
managed facility that would normally be dry except for rain or snow melt events. Sportsfield
development for both the school and the community could also be designed within the school site and
would likely overlap with the storm water management facility.
This site would be designated for municipal reserve, school reserve, a public utility lot or a combination
thereof. It is anticipated that the land would only be designated upon the need for its use for these
community purposes. If the required ten percent municipal reserve is provided as open space elsewhere
24
in the plan area, this site would have to be purchased from the developer. If the school site is designated,
it would be classified under the Land Use Bylaw as Institutional/ Recreational (I-R).
In the event that the land is not required for community purposes, a "shadow plan" of the area should be
contemplated so that the land is not unduly detached from and would function with the remainder of a
residential neighbourhood.
iii) Parks, Open Space, & Walkways
Parkland and related open spaces will occupy nearly 9 hectares (22 ac.) of land within the development
area. Subdivision regulations require ten percent of the development area, approximately six hectares,
to be provided for Municipal Reserve and or School Reserve. If a school site of four hectares is
dedicated, only two hectares will remain for other public open space. However, this amount of space
may be inadequate for the kind of neighbourhood Cottonwood Estates is intended to be. To help resolve
this situation, much of the land that is being provided for storm water management and other utility
rights-of-way will be amalgamated with dedicated municipal reserve to provide multi-purpose open
space. Any open space provided beyond the required 10% would be provided at the developer's
prerogative.
Open space will be available for active and passive recreational use but will also provide for the
movement and detention of storm water during rainstorm and snowmelt events. The system of
integrated open space thus provided extends throughout the development area and is either adjacent to or
within short walking distance of all lots within the neighbourhood. Walkway connections have been
25
allowed for at several locations to both facilitate accessibility within the neighbourhood and to
adjoining areas of the larger community.
Efforts will be made to preserve existing trees wherever possible since this vegetation helps establish
character to the development area. Although not part of the development area, the adjacent S.M.R.I.D.
canal right-of-way contains marshland habitat that provides amenity value to the entire community.
Currently used by town residents, the existing "ditch-rider" road is a recognized pathway along this
marshland. The S.M.R.I.D. will continue to utilize this roadway and its foremost purpose will be for
irrigation facility maintenance access.
An irrigation check structure at the mid-way point of the canal is more or less in line with 22nd Street.
This narrow, dam-like structure is used as an informal crossing of the canal. Whether or not 22nd
Street is extended into the development area in the future, this spot would continue to be a good location
for a pedestrian crossing. For this to happen, the S.M.R.I.D. would require an appropriately engineered
bridge structure.
26
b) Road Network
The road network described below is illustrated on Figure 7.
i) Roadways & Access Points
(1) Access to Development Area
(a) Fairway Drive, Twenty-second Street & Twenty Fourth Street
Fairway Drive, 22nd Street and 24th Street are adjacent to the Cottonwood development area and present
excellent opportunities for future access. Twenty-Fourth Street evolves into Fairway Drive as it enters
Land O'Lakes near the Northwest corner of the development area. With a suitable land acquisition
north of the SMRID canal, and with the construction of an appropriate crossing of the canal, this area
of the site will become a prominent entrance into the new subdivision. This location also provides a
suitable location for pedestrian access to the north.
Twenty-second Street is situated mid-way along the northern site boundary and is developed as far as
the east-west lane serving the lots fronting onto 24th Avenue. An extension of this street into the
development area would assist in the distribution and balancing of traffic originating from or
destined for the Cottonwood Estates. As with the crossing connecting with Fairway Drive/24th Street,
an appropriate canal crossing would be required. This centralized location also provides a very good
placement for pedestrian access to the north for schools, parks and commercial areas.
At the time Land O'Lakes was planned, Fairway Drive was designed to extend into the Cottonwood
Estates development area to provide connectivity between the Southeast and Southwest ¼'s of Section
10. Fairway Drive currently extends nearly to the east edge of the Southwest ¼ where it terminates in
27
a cul-de-sac. The potential extension of Fairway Drive into Cottonwood Estates will be precluded by
officially closing the road beyond where it currently ends in a cul-de-sac.
(b) Twentieth Street/ Highway 845
Provision has been made for widening 20th Street along the eastern part of the plan area however this
widening will eventually need to extend a bit further along past the existing farmstead and the canal
to the north. The existing site access that currently intersects with 20th Street at 30th Avenue will
become a primary access route for the Cottonwood Estates development in the future.
Normally Alberta Infrastructure and Transportation, which is the road authority, would prefer access
to Secondary Roads at spacings of 400 meters in urban density situations. Existing access points
may possibly remain however, until development intensifies to a level where it is advisable to truncate
inadequately spaced access. No other direct access will be permitted by Alberta Transportation, thus
other access options have to be evaluated. One such option is a service road parallel to Twentieth-street
as part of the internal circulation system. This particular option does not appear to be a suitable
alternative when considered in conjunction with the internal circulation system proposed for the
development area.
28
(c) County Township Road 9-1
The County Township Road may eventually provide an alternate means of access for southbound and
eastbound traffic. This southern access would interconnect with the internal road network within the
plan area. If this road is ever considered to become more than a localized rural road, it would have to be
widened to an appropriate width.
This right-of-way is ample enough to provide for road widening. An equally wide strip of land along
the eastern half has been reserved for road widening and to provide sufficient space for appropriate
development setbacks.
In addition, appropriate discussions and agreements between the Town of Coaldale and the County of
Lethbridge would need to take place.
ii) Circulation Within Development Area
(1) Roadway Hierarchy
Cottonwood Estates will utilize a circulation system consisting of three levels of roadway and an
integrated pathway system. These levels include: major collector; minor collector and local roads which
are illustrated on Figure 7.
29
(2) Major Collector Roadways
Gently curving through the development area will be a 23 meter street that connects major access
points at Fairway Drive to the west and 30th Avenue to the east. These streets are proposed to be widened
to as much as 30 meters to allow for channeled traffic lanes and landscaped gateway features. This
major collector road is intentionally curved to create a more pleasing streetscape and to assist in
reducing traffic speed. Such intersection spacings range from a minimum of 75 meters to a
maximum of 270 meters. There are three 4-way intersections with the major collector within the
development area. All intersections between the major collector and other collectors are designed at or
very close to 90 degrees.
Direct access from individual lots has also been somewhat limited to minimize future intersection
congestion, and to maximize the carrying capacity of the road without reducing the quality of life of
future residents on adjacent lots.
Residential lots near the 20th street access have been designed as reverse frontage lots so that they will
not access the major collector but the minor collector to the south instead. Residential driveways
should be restricted so that they are not within 30 meters of an intersection with the major collector.
Road right-of-way width may be slightly increased at both the Fairway Drive and 30th Avenue
accesses to permit construction of subdivision gateway features. There is currently a noteworthy grade
30
difference between 20th Street and the proposed major collector. This grade difference will be reconciled
as part of the earth balancing that will be required on the site.
(3) Minor Collector Roads
Minor Collector roads will provide an intermediate level of access within a 20 or 23 right-of-way.
Collector roads within Cottonwood Estates are designed as a northerly section providing good vehicular
access from the school site to the major collector and Hwy 845 and a souitherly concentric inner-ring
roads with which all local roads will intersect.
A northern section of the of the collector system stretches from Hwy 845 westerly, then southerly
along the west side of the school site connecting to the major collector.
The southerly inner ring loops around the central area south of the major collector with which it
intersects at two locations. Provision has been made for a connection to the County township road at
the midway point along the southern boundary.
These collector roads will all provide direct access to adjoining lots.
(4) Local Roads
Local roads consist of a variety of configurations including crescents and cul-de-sacs that provide
access to adjacent lots, normally within 16.5 meter. These streets will convey traffic to collector roads
and by virtue of their narrower width, the maximum operating speed would be 50 kilometers per hour.
31
This level of roadway will include more 4-way intersections. Intersection spacing is intended be not
less than 80 meters. Cul-de-sacs range from 65 meters to 125 meters in length and the minimum cul-
de-sac bulb radius would be 15 meters. The furthest distance any lot is anticipated to be from an
intersection is approximately 200 meters.
(5) Pathway System
Non-motorized access within the development area will take place through a series of pathways that are
integrated with the open space system. These pathways will connect with park spaces, the future school
site, the commercial site and public use site thorough both the parks and the stormwater management
facility areas. The S.M.R.I.D. ditch rider road could further augment this system. Links with other
neighbourhoods will be made possible in conjunction with the street system and through walkway
breaks in development.
Because this system will rely on stormwater routes, construction of walkways should ensure usability
except in high water storm drainage situations where the utility function would need to prevail.
Surfacing should also ensure that all weather use is possible. Intersections of pathways and roadways
would generally occur at street intersections except where there is a stormwater route or utility corridor
interface.
c) General Servicing Concept & Phasing
i) Sanitary Sewage Collection
The following section is a general description of the sanitary sewage collection system. The system is
illustrated in Figure 9 while details of the system are contained within the Master Servicing Plan from
Martin Geomatics Consulting Ltd. Found in Appendix 2.
32
Sewage generated within the development area will be collected in pipelines that will connect with the
existing 250 mm sanitary sewer that services the Land O'Lakes subdivision. Sewer lines will
normally be a minimum of 200 mm in diameter. This collection system will rely on gravity flow,
has been sized to accommodate the levels of service required within the development area and will follow
the road network. Sewer line depth will become shallower towards the east edge of the development
consequently careful site grading will be necessary at to ensure appropriate sewage flows.
Foundation drainage connections to the sanitary sewer will not be allowed by the Town of Coaldale due
to a lack of capacity in the sanitary system downstream from the Cottonwood Estates development
area.
33
ii) Water Supply And Distribution System
The following section is a general description of the water supply and distribution system. This system
is illustrated on Figure 10 while details of the system are contained within the Master Servicing Plan
from Martin Geomatics Consulting Ltd. Found in Appendix 2.
Domestic water supply will originate from the treated pipeline already located in the development area.
The water distribution system will follow the road network and has been sized to accommodate the
levels of service required within the development area. These service levels will be compliant with Alberta
Environment and Town of Coaldale standards.
iii) Storm Water Management System
The following section is a general description of the storm water management system. The system is
illustrated in Figure 11 while Details of the system are contained within the Storm Water
Management Plan from Martin Geomatics Consulting Ltd. found in Appendix 2.
Storm water management is the single-most critical determinant in the planning and subdivision
design of Cottonwood Estates. Storm water management facilities (SWMF) use large quantities of
land thus influence lot yield and servicing costs within the development area. To ensure property is
safe from flooding, storm water passage routes require additional land and must be carefully
considered otherwise land could be wasted and unnecessary site grading may take place. Storm water
management facilities also significantly influence the amount of park space, its location and how it
is developed.
34
Cottonwood Estates development area appears to be relatively flat but declines five meters, across a
gradual slope, from west to east where two prominent low spots become apparent along the easterly edge.
The existence of S.M.R.I.D. works adjacent to and within the site presents a dam-like effect that
hinders drainage. To further complicate the situation, natural drainage through the development area
and adjacent land to the south, in the County of Lethbridge, has been altered by the construction of
Highway 845 and the dam-like effect it has. The cumulative effect of this situation will therefore
require both short term and long term solutions for storm water management.
Through site grading and swales in linear open spaces, storm water will be conducted to two SWMF's.
The first facility, a dry pond of approximately 16,000m³, will be situated in the north-central portion
of the plan area within a site of about 2 hectares. A second, larger dry pond of 36,000 m³ will be
required on the east central side of the plan area within a site area of approximately 2.4 hectares.
The southeast corner of the site will function as a storm water detention area until a long term solution
to a comprehensive South Coaldale storm water management that has been determined.1. Construction
of housing will be precluded until the long-term storm water solution has been derived.
Roadways within Cottonwood Estates will be developed to an urban, standard with curb and gutter,
thus there will be no roadside swales as part of the stormwater management system however, there will
35
be detention capability designed into the pathway system. With appropriate surface grading, early
phases of development are not expected to require fully developed storm water management facilities
since there will be a great deal of vacant, arable land to absorb surface runoff.
The Town of Coaldale has indicated that it will manage off-site storm water runoff that cannot be
managed within Cottonwood Estates, in a staged fashion dependent upon the availability of the
necessary funding and/or upon reaching an agreement with the County of Lethbridge. The Town has
also indicated it's willingness to negotiate with the developer of Cottonwood Estates for the cost of
providing additional storage.
Buildings and critical improvements, including infrastructure, will be required to be constructed at
elevations that would protect them from any flooding that may result from a 1:100 year storm event.
iv) Shallow Utilities
Shallow utilities, including electrical services, natural gas, telephone and cable required to service
Cottonwood Estates will be extended into the development area in consultation with the respective utility
companies. These utility rights-of-way will be required for all shallow utilities and will not be within
road rights-of-way. Details will be determined at the subdivision stage.
1 Town Council has requested the developer of Cottonwood Estates to work with Operations & Engineering
Services Committee to ensure that a reasonable amount of staged detention or retention storage is provided for
runoff entering the development area from the County of Lethbridge.
36
v) Domestic Irrigation
Agricultural land within Cottonwood Estates is currently irrigated and the development area also
contains irrigation works that convey water to downstream users. Preserving the continuity of
irrigation service to downstream users, when no longer needed for agricultural purposes in the
development area, is a mandatory requirement of the irrigation district. The S.M.R.I.D. has indicated
that a flow rate of 150 USGPM will be necessary for close to five hectares of irrigable land in the
Southwest ¼ of Section 11, Township 9, Range 20, West of the 4th Meridian.
The ability to carry on using irrigated water for domestic purposes is also an advantage for the
development since more expensive treated water would otherwise be used for residential and parkland
lawn watering. Current alignment of the downstream supply as well as its open ditch method will both
be replaced by a new, subsurface pipeline designed to S.M.R.I.D. specifications.
d) Sidewalks, Street Lighting and Road Standards
Together with street lighting, sidewalks are intended to be provided throughout Cottonwood Estates.
Cross-sections that indicate locations, widths, depths of the appropriate features are provided in
Appendix 4.
37
e) Potential Staging
Future subdivisions will comply with the land use concepts of figure 6, road design of figure 7 and the
Town's engineering documents or standards.
The following section is a general description of the development staging plan. This staging plan is
illustrated in Figure 12 while details of the utility staging are contained within the Master Servicing Plan
from Martin Geomatics Consulting Ltd. found in Appendix 2. Changes made to the Master Servicing
Plan may only take place with the Town's approval.
Cottonwood Estates will be staged in a series of subdivisions in response to market conditions. Since build-
out is expected to take several years, the timing and phasing of development will be very important so as to
be as economical as possible.
Development is intended to commence in the vicinity of the northwest corner of the development area. This
is the most cost effective commencement point since both water and sewer line extensions would be the
shortest distance from existing connection points. Extending a roadway from Fairway Drive would also be
the shortest distance of any of the other possible roadway extensions. This extension will involve some land
acquisition to ensure an appropriate alignment and connection point.
Beginning development at a northwest location also provides a variety of optional types of lots that could
initially be brought on-stream. The land use concept indicates that "large lots" would be offered on the
northeast side of the entrance road while an "upscale adult villa site" is possible on the southwest side.
38
South of the possible upscale adult villa site is a stretch of "estate lots". In response to market demand,
large lot development could continue in an easterly direction while estate lot development could continue in
a southerly direction. A potential lot layout scheme is illustrated in Appendix 6.
"Enhanced setback" lots could be made available within the first stage of development if desirable.
"Standard lots" could start with the development of a cul-de-sac behind the enhanced setback lots. Across
the street to the east of the stretch of estate lots would be another stretch of "enhanced setback lots". These
enhanced setback lots would provide a transition between the very large estate lots to the west and the
smaller, "standard lots" to the east.
This potential first stage of development could also provide a multi-unit residential site at an appropriate
location. Park space would also be included within this development stage as indicated on the land use
concept.
Generally the phasing plan is described as follows:
- Phase 1 of the plan would include all the land above the 867.3 meter contour.
- Phase 2 would include the remainder of the land within the plan area.
- Development will be staged in logical, market-oriented clusters.
- Each stage will be numbered but may not necessarily be developed in consecutive order.
Phases and stages are be indicated on Figure 12 .Future stages would be anticipated to continue in easterly
and southerly directions as warranted by market conditions. The staging map, illustrates potential
development stages.
39
f) Sustainable Community Development
Cottonwood Estates Area Structure Plan has attempted to take a more holistic approach to neighbourhood
planning by incorporating features that address sustainability. Responsibility for a "sustainable approach"
to community development is shared among various levels of government, community planners, land
developers, property owners and the general public. According to Steven Peck and Guy Dauncey, two
sustainable community consultants who conducted research for Canada Mortgage and Housing, there is an
increasing recognition that the manner in which land is developed and redeveloped is a key determinant in
the social and environmental health and economic well being of Canadians2. Peck and Dauncey have
identified three major levels at which actions in support of sustainable community development or barriers to
implementation occur:
- the planning and infrastructure level;
- the development site level; and
- the building level
Peck and Dauncey have identified 12 features of community sustainability which are incorporated within
these three major levels. While not all of these features are represented, several aspects of Cottonwood Estates
have integrated sustainability features, In particular, the following:
- ecological protection
recognition of adjacent wetlands in the SMRID right-of-way
significant trees have been incorporated into area of open space wherever possible
staging of development to preserve the use for agricultural purposes for as long as
possible
2 REFERENCE: New Urban Agenda - 12 Features of Sustainable Community Development: Social, Economic and Environmental Benefits;
Steven Peck, Peck & Associates & Guy Dauncey, Sustainable Communities Consultancy
40
most lots may be larger than the norm thus enabling owners to plant gardens if
they so wish
- Urban design
Cottonwood Estates provides a well designed, spacious living environment adjacent to
actively farmed land
Although the site is basically flat, views will be afforded to a high percentage of lots
adjacent to open spaces
- sustainable transport
walkway routes that connect to adjoining neighbourhoods and major non-residential
land uses have been planned throughout the development area
- affordable housing
Cottonwood Estates will contain a range of housing types, lot sizes and prices
Medium-density residential sites are close to walkways and within walking
distance of the school site and open space sites
- livable community
the developer will place gateway features at major entrances to the neighbourhood
architectural controls will be employed
traffic calming with curved streets and cul-de-sacs
there is an over dedication of municipal reserve
storm water management facilities have been designed to integrate with open space
system
a school site has been provided
- sewage and storm water management
multi-purpose storm water management facilities are an integral component of the
neighbourhood design
41
- water conservation
use of irrigation water for domestic watering purposes has been incorporated where
possible thus avoiding use of treated water
- energy conservation
strong east-west road alignment in several locations throughout the neighbourhood to
maximize solar access opportunities
curvilinear collector streets to minimize effects of strong winds
energy efficient designs will be encouraged in the architectural control of the
development
g) Architectural Control
Architectural controls that are intended to provide a set of rules to ensure a reasonably high quality
development will be utilized in the Cottonwood Estates development area and to ensure an appropriate level
of housing design compatibility. Architectural controls may vary to some extent depending on the
location within the development area and will be registered on lot land titles by the developer.
Architectural control will be administered by the developer or his designate.
Typically the controls that will be in effect within Cottonwood Estates include the following:
- minimum dwelling unit area and site coverage (building footprint)
- diversity in home design
- incorporation of energy efficiency features
- roof pitch & materials
- exterior finishing materials
- fencing materials
- minimum landscaping requirements
42
The developer may undertake construction of certain stretches of fencing or installation of certain aspects
of landscaping to establish the character of the development.
h) Community Mailbox Locations
Community mailboxes will be distributed throughout the development area as required by and in
consultation with Canada Post.
i) Alignment With Municipal Development Plan
The following table indicates how the Cottonwood Estates Area Structure Plan complies with the policies of
the Town of Coaldale Municipal development Plan.
Policy
Area of Compliance
3.1
- area structure plan prepared prior to land use reclassification from Urban Reserve
3.2
ASP has considered:
- ease of servicing
- storm water management
- provision of alternate types of housing
- linkage of open spaces
- transportation patterns
- compatibility with existing land uses
3.3
- ASP will be circulated to concerned agencies and the County of Lethbridge
3.4
- All mandatory setbacks will be observed
3.9
- senior's housing close to potential commercial and public use sites
3.11
- site is a designated growth area as identified by the Town
3.13
- commercial site requested by Town intended for neighbourhood level service
3.17
- architectural control will be utilized
3.24
- ASP adhering to recommendations from MPE storm water management study
3.27
- High design standards will be used for landscaping, entrance features created
43
for subdivision gateways
3.30
- Care has been taken to minimize difficult to maintain park areas
3.30
- Park linkages have been provided
3.32
- Storm water management facilities integrated with parkways/pathways
3.38
- Developer has shown willingness to cooperate with Town and school district to
provide school reserve
i) Consultation Process
i) Open House
An open house was held at the Land O'Lakes Golf Course Club house on the evening of May 18, 2005. As part of an
ongoing planning process, this open house was an opportunity for Mr. Frache to seek input from interested and
concerned citizens on the plan. Invitations were mailed to approximately 80 adjacent landowners, the Town Council,
the Town administration, adjacent County landowners, the County of Lethbridge, the Regional Police Service and the
Oldman River Regional Services Commission. An advertisement was also placed in the Sunny South News to notify
the general public of the event.
The Open House was an informal come-and-go event and no formal presentations were be made. Staffs from Plains
West Planning Services, Martin Geomatics Consulting Limited and the owner were on hand to explain features of the
plan and answer questions that arose. Several Town Councilors and ORRSC staff were also on hand to field
questions regarding process issues and other Town matters. The Open House featured display panels depicting:
- current conditions of the property;
- the purpose, goal, objectives and planning context for the plan area;
- the land use concept and proposed infrastructure systems;
- features to promote sustainability;
44
While 75 guests signed-in, it was estimated that at least 100 people dropped-in to review the plans. Although only 2
people actually provided written comments, the overall impression of he plan was positive.
ii) Town Administration, Planning and Engineering Advisors
Several meetings were held with Town of Coaldale administration together with staff from the Oldman River
Regional Service Commission, the Town's planning advisors and staff from M.P.E. Engineering, the Town's
engineering consultants. These meetings were productive and greatly enhanced the context and content of the p area
structure plan.
iii) St. Mary's River Irrigation District
The consultants and Mr. Frache had several meetings and conversations with staff of the S.M.R.I.D. to resolve
issues arising from the complexity of the irrigation system.
iv) Alberta Transportation and Utilities
Consulting staff met with Alberta Transportation and Utilities staff to ascertain transportation issues and
requirements from the provincial perspective which have been incorporated into the plan.
v) Land O'Lakes Golf Course Management
Mr. Frache met with representatives of Land O'Lakes to resolve boundary issues that arose during the plan
preparation.
45
APPENDICES
1.
Land Ownership Information
2.
Master Servicing Plan
3.
Potential Land Use Classifications
4.
Gateway Design Alternatives
5.
Street Cross Sections
6.
Potential Lot Layout
46
Appendix 1
Land Ownership Information
47
Appendix 2
Master Servicing Plan
Part 1
Drainage and Stormwater Management Concept
The following outlines the concept for drainage and stormwater management for the development of the
Southeast Quarter of Section 10, Township 9, Range 20 West of the 4th Meridian (the "Subject Area").
1. Existing Conditions
Presently, drainage across the subject area is overland, roughly from the west to a 900-mm diameter culvert
under Highway 845. This culvert discharges into an open channel known as the South Coaldale Drain.
According to the South Coaldale Stormwater Management Plan (MPE Engineering Ltd., November 2002),
the subject area ("Area 2" in the MPE Report) also receives drainage from Section 3-10-9-4 (the square-mile
immediately south, "Area 1" in the MPE Report) which is outside the Town Limits in the County of
Lethbridge. Contributing areas and present land uses noted in the MPE Report are a follows:
Catchment Areas and Predicted Runoff Volumes (per MPE, p. 14)
Area Number
Gross Area
(ha)
Land use
Peak flow
predicted in
100-year event
(m3/s)
Runoff volume
predicted in
100-year event
(m3)
1
276
Agriculture
4.24
122,000
2
66
Agriculture
2.34
29,200
Due to capacity limitations in the South Coaldale Drain and the culvert under Highway 845, localized
flooding occurs in the subject area during storm events (MPE, p. 9).
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2. Initial Development Drainage Concept
To account for existing runoff from Area 1 and development in the subject area and the limited capacity of the
South Coaldale Drain, it is estimated (MPE, p. 19) that 124,500 m3 of detention storage is required. Therefore,
development of the east part of the subject area (below the 867.3-m contour) will be deferred until such time as
flows from Area 1 area controlled such that ponding in the subject area is not necessary to prevent surcharge
in the culvert under Highway 845. Figure No. 5 shows the extent of the ponding necessary to obtain 124,500
m3 of detention storage given the initial site grading. For interim development, it is assumed that the 900-
mm diameter culvert under Highway 845 already provides adequate flow control to prevent flooding in the
South Coaldale Drain.
Given that an urban cross-section is proposed for the streets, runoff will be drained using a conventional dual-
drainage (major/minor) storm sewer system. Street and lot drainage (with the exception of foundation
weeping tile, see below) will initially be directed to street gutters. Catch basins will be placed at strategic
positions to intercept these gutter flows and direct them to the storm sewers. These storm sewers (referred to as
the "minor" system) will drain, by gravity, to an outfall located as shown on Figure No. 11.
The minor system will be designed to discharge the peak flow estimated for a design storm with a 5-year
return period given full development without surcharge in the pipes. Runoff in excess of this volume will be
directed via road gutters and grass swales (referred to as the "major" system) to discharge at a similar
location to the storm sewers. The major system will be designed such that peak runoff from a full design
storm with a 100-year return period can be discharged without flow depths and velocities exceeding those noted
Table 3-1 of Stormwater Management Guidelines for the Province of Alberta (Alberta Environment, January
1999).
As the ponding onsite will likely induce surcharge in the proposed minor system, analysis of the hydraulic
grade line (HGL) in these pipes will be conducted as part of the overall subdivision design. To protect
buildings from flooding due to water backing up in the storm sewers and flooding the foundation weeping
tile, it is assumed that the lowest top of footing (LTF) elevation of all houses will be at least 0.3 m higher than
the HGL in the adjacent storm sewer.
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3. Future Development Drainage Concept
At such time as runoff from offsite (i.e. Area 1) has been controlled to such a rate and quantity that backup
of stormwater upstream of the Highway 845 culvert is not a concern, the east part of the site can be developed.
Again a dual-drainage storm sewer design will be employed, similar to the system specified above. To control
runoff from the development, stormwater detention ponds are envisioned at locations shown on Figure No. 11.
These ponds will have active storage capacities such that all on-site runoff resulting from a design storm with
a 100-year return period for the fully-developed site can be detained. Once the storm event has passed and the
level water in the South Coaldale Drain allows it, a storm water pumping station will draw down the pond at
such a rate that the canal does not overflow and downstream residents and landowners are not adversely
affected.
50
Part 2
Sanitary Servicing Concept
The following details the conceptual design for conveying wastewater from the proposed development.
1. Existing Sanitary Sewers
Presently, a Town gravity sanitary sewer crosses the subject area from west to east. The sewer is located
approximately 400 m north of the south section line. It consists of a 250-mm diameter pipe with a continuous
slope from west to east of 0.36%. Assuming a smooth-wall concrete or PVC pipe, flowing full, the sewer could
discharge wastewater at a maximum rate of 36 L/s. This sewer presently serves 100 homes in the subdivision
located to the west of the subject area. Assuming three (3) people per home and a daily wastewater flow of 450
L/person/day, the expected daily flow through the sewer is 135,000 L/day. Using a peak factor of 3.0, the
design peak flow in the sewer is estimated at 4.7 L/s.
2. Future Servicing
Using a value of 30 people per hectare of the subject area generating 450 L/person/day the expected average
daily flow from the 66-ha subject area is 891,000 L/day. A peaking factor of 3.0 would gives a design peak
flow estimation of 31 L/s. Total daily flow is estimated at 1,026,000 L/day. This gives a peak flow of 35.6
L/s. Given a full-flow capacity of 36 L/s, the trunk sewer has adequate capacity. It is assumed that the Town
of Coaldale's existing infrastructure has adequate capacity to accept the additional wastewater generated by
this development.
Proposed sanitary sewers will be gravity sewers with a minimum diameter of 200 mm. All public mains will
be PVC and will be designed with adequate slopes to ensure a minimum velocity of 0.7 m/s as specified in
Standards and Guidelines for Municipal Waterworks, Wastewater and Storm Drainage Systems (Alberta
Environment, December 1997).
3. Conceptual Sanitary Servicing Plan
The conceptual sanitary servicing plan is shown on Figure No. 9.
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Part 3
Water Supply and Distribution System Concept
The following details the conceptual design for the water supply and distribution system for the proposed new
subdivision.
1. Existing Water Supply
Treated water is supplied by the Town of Coaldale. It is assumed that the Town's water infrastructure has
adequate capacity to accommodate this development. Presently, water mains exist at the following locations:
a. A 300-mm diameter main runs from west to east across the site. From the west, the main enters the
subject area at the southeast corner of the site and proceeds along the south section line. Approximately
400 m east, the line deflects north. At a point approximately 400 m north of the section line, this main
deflects east, running to the east section line, where it passes under Highway 845.
b. A 200-mm diameter water main in Fairway Drive (at the northwest corner of the proposed
development).
c. A 150-mm diameter water main from 24th Avenue from 24th Street to 21st Street.
d. A 150-mm diameter water main on the west side of Highway 845 (20 Street) which ends immediately
north of the existing canal right-of-way.
Hydrants exist at the following locations:
a. 25th Avenue, immediately east of 24th Street/Fairway Drive,
b. Highway 845 (20th Street) immediately north of the existing irrigation canal right-of-way (25th Avenue),
c. 30th Avenue, 20 m east of Highway 845.
52
Alberta Environment states the following guideline for pressures in a water distribution system:
"[...] SHOULD BE DESIGNED TO HANDLE A NORMAL OPERATING PRESSURE
BETWEEN 350 kpa (51 psi) AND 550 kpa (80 psi) UNDER A CONDITION OF MAXIMUM HOURLY DESIGN FLOW."
Additionally, based on Water Supply for Fire Protection (Fire Underwriters Survey, 1990), the Town of Coaldale
requires the following sustained pressures and flows be available for fire protection. For residential subdivisions,
a flow of 3,400 L/min (900 USgpm) at a residual pressure of 138 kPa (20 psi) must be available at any given
hydrant. From any three (3) adjacent hydrants, total flow must exceed 5,000 L/min (1,320 USgpm) at a
residual pressure of 138 kPa (20 psi).
According to MPE Engineering Ltd., who administer the Town of Coaldale's water modeling system, there is
adequate pressure and flow available for the existing adjacent developments. MPE assumed the following:
-
a peak daily demand at each hydrant of 27.2 L/min (7.2 USgpm),
-
rural water demands,
-
McCain plant production requiring one (1) train per day (not accounting for future expansion).
No specific hydrant testing data was made available. However, it is assumed that the model used by the Town is
properly calibrated and gives an accurate representation of the Town's existing water distribution system.
2. Proposed Water Supply and Distribution
To service the proposed development, it is proposed that new water mains tie to the Town of Coaldale's existing
mains at the following points:
a. To the existing 200-mm diameter main in Fairway Drive, immediately northwest of the proposed
development,
b. To the existing 300-mm diameter main, 400 m east of the west quarter line and 25 m north of the south
section line (ties east and west),
53
c. At approximately three (3) points on the 300-mm diameter main east of Highway 845,
d. Extension of the existing 150-mm diameter main west of Highway 845 (20th Street) approximately 30
m south to tie to the development,
e. Extension of the main in 22nd Street approximately 30 m to the new development.
As part of the design process, the proposed water distribution system will be analyzed using an appropriate
computer model. Peak daily demand assumed for the new development is 35 L/min (9 USgpm) at each hydrant.
All mains will be sized to ensure adequate water supply for fire prevention and domestic use. As a minimum, the
following sizes are assumed:
-
All looped mains will be minimum 200-mm diameter, C900 PVC,
-
All stubbed mains will be minimum 150-mm diameter, C900 PVC.
A preliminary analysis based on the above indicates that no reservoirs, booster pump stations or pressure-
reducing valves are assumed required for this development.
3. Conceptual Water Servicing Plan
The conceptual water servicing plan is shown on Figure No. 10.
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Appendix 3
Potential Land Use Classifications
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Appendix 4
Gateway Design Alternatives
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Appendix 5
Street Cross Sections
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58
59
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Appendix 6
Potential Lot layout
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