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SOUTH COALDALE
Revised
Area Structure Plan
(Portion of Area North of 30th Ave)
Prepared by:
MARTIN GEOMATIC CONSULTANTS LTD.
Amended by:
ISL Engineering and Land Services. Ltd.
MAY 2021
(Approved by Bylaw 820-P-06-21 on July 12, 2021)
South Coaldale Revised Area Structure Plan (Portion of Area North of 30th Avenue)
May 2021
Page 2
Table of Contents
Table of Figures .................................................................................................................. 3
I.
Introduction ................................................................................................................. 4
A.
Purpose ................................................................................................................... 4
1.
Legislative Framework ...................................................................................... 4
2.
Relation to Other Plans ...................................................................................... 6
3.
Town Planning Process ...................................................................................... 7
B.
General Location and Plan Area ........................................................................... 8
II.
Site Analysis ........................................................................................................... 10
A.
Site Characteristics ............................................................................................. 10
B.
Soil Classification ................................................................................................ 10
C.
Water and Hydrology .......................................................................................... 10
D.
Habitat and Vegetation ....................................................................................... 12
E.
Environmental, Historical and Archaeological Significance ............................. 12
F.
Existing Land Use ............................................................................................... 12
G.
Constraints .......................................................................................................... 12
1.
Stormwater Management and Drainage ......................................................... 12
2.
Sanitary Sewer Capacity ................................................................................. 12
3.
Access and Circulation ..................................................................................... 13
4.
Existing Irrigation Infrastructure ................................................................... 13
H.
Opportunities ....................................................................................................... 13
1.
Encouragement of Compatible Land-Uses ...................................................... 13
2.
Permitting More Choice in Housing ................................................................ 14
3.
Proximity to Services ....................................................................................... 14
4.
Additional Parks and Open Space ................................................................... 14
III.
Proposed Land Use and Design .............................................................................. 15
A.
Proposed Land Use .............................................................................................. 15
B.
Population and Housing Densities ..................................................................... 15
IV.
Proposed Infrastructure ......................................................................................... 16
A.
Access and Circulation ........................................................................................ 16
1.
Highway 845 Access ......................................................................................... 16
2.
Other Connections ............................................................................................ 16
3.
Internal Roads .................................................................................................. 16
4.
Pathway Connections ....................................................................................... 16
B.
Public Utilities and Servicing ............................................................................. 17
1.
Sanitary Sewers ............................................................................................... 17
2.
Drainage and Stormwater Management ......................................................... 17
3.
Potable Water ................................................................................................... 19
4.
Community Irrigation System ......................................................................... 20
5.
Shallow Utilities ............................................................................................... 20
C.
Solid Waste .......................................................................................................... 21
V. Subdivision and Development Staging ..................................................................... 23
VI.
Development Control .............................................................................................. 23
VII. Development Agreements ....................................................................................... 23
South Coaldale Revised Area Structure Plan (Portion of Area North of 30th Avenue)
May 2021
Page 3
VIII.
Architectural Control Guidelines ........................................................................ 23
Appendix A - Included Figures ........................................................................................ 24
Table of Figures
Figure 3.0 - Schematic of Coaldale's Planning Process .................................................... 7
Table 1.0 - Population and Housing Densities ............................................................... 15
Table 2.0 - Preliminary Sanitary Sewer Design ............................................................. 22
Figure 1.0 - General Location Plan from South Coaldale ASP (1999) ........................... 25
Figure 2.0 - General Location Plan ................................................................................. 26
Figure 4.0 - Existing Land Conditions ............................................................................ 27
Figure 5.0 - Existing Land Use Designation .................................................................. 28
Figure 6.0 - Proposed Land Uses .................................................................................... 29
Figure 7.0 - Proposed Internal Road Network ................................................................ 30
Figure 8.0 - Proposed Sanitary System........................................................................... 31
Figure 9.0 - Proposed Storm System ............................................................................... 32
Figure 10.0 - Proposed Water System ............................................................................. 33
South Coaldale Revised Area Structure Plan (Portion of Area North of 30th Avenue)
May 2021
Page 4
I. Introduction
A. Purpose
The South Coaldale Revised Area Structure Plan (SCRASP) was developed in
2010 to (1) amend the existing South Coaldale Area Structure Plan1 (hereafter
the original ASP) to reflect changes to assumptions, regulations and landowners'
development goals and (2) to provide a framework to allow higher density
residential land use compatible with adjoining areas and consistent with an
urban municipality for the land north of 30 Avenue. The original ASP is still in
effect for the properties south of 30th Avenue. The SCRASP (2021) updates a
portion of the lands north of 30th Avenue and replaces the previously approved
SCRASP (2010).
1. Legislative Framework
The SCRASP complies with the following legislative documents and
statutory plans.
a)
Municipal Government Act (Alberta)
The SCRASP was produced in accordance with Section 633 of the
Municipal Government Act (Alberta). The intent of an Area
Structure Plan (ASP) is to create a framework for future
subdivision within the "site area" (as defined in Sub-section I.B). In
particular, this document will outline the following
-
sequence of development,
-
proposed land uses,
-
population density,
-
access and circulation,
-
location and general design of public utilities and
-
other related matters.
b)
South Saskatchewan Regional Plan (SSRP)
The SSRP is a legislative document that was prepared in
accordance with Section 13 of the Alberta Land Stewardship Act
(ALSA). It sets objectives for the management of land and natural
resources, while balancing long-term social, economic, and
environmental goals of the province. All municipal statutory plans
and relevant documents are required to align with the objectives
and strategies of the SSRP.
1 Oldman River Intermunicipal Services Agency (now ORRSC), South Coaldale Area Structure Plan,
1999, Adopted as Town of Coaldale By-law #407-P-07-99 on 14 July 1999.
South Coaldale Revised Area Structure Plan (Portion of Area North of 30th Avenue)
May 2021
Page 5
c)
County of Lethbridge & Town of Coaldale Intermunicipal
Development Plan (IDP)
The IDP2 is intended to address future growth and development-
related matters of joint interest between the County and Town,
including future land use surrounding the Town.
d)
Town Plan
-
The Town's Municipal Development Plan (Town Plan, Bylaw No.
786-P-09-20)3 provides strategic direction to guide future growth
and development within the Town. It forecasts population growth,
directs future land use, and anticipates future transportation and
servicing needs within the Town. It also serves as an important
decision-making tool for Council, administration, landowners,
residents, and developers on matters related to community growth
and development. The Town Plan was updated after the
preparation of the SCRASP (2010). The Town Plan identifies the
site area as an "Area of Change" which means that the area is
already established, and both incremental and larger-scale
development has been occurring over time. Town Plan directions for
growth and change in Areas of Change that are being reflected in
the 2021 revision include:
-
Maximizing the use of existing lands within the Areas of
Change before developing lands within the Areas of Growth
-
Expanding housing opportunities and increasing residential
density throughout Coaldale
-
Including active transportation infrastructure in new
developments and promoting upgrades in older areas
-
Balancing urban development with the inclusion of
naturalized areas and infrastructure that emulates and
mimics natural processes
-
Ensuring development in the Area of Change is intentional
and guided by comprehensive planning documents such as
the Town Plan, Area Redevelopment Plans, conceptual
schemes and mechanisms in the Land Use Bylaw
2 County of Lethbridge & Town of Coaldale, Intermunicipal Development Plan, County Bylaw 1337, as
amended by Bylaw No. 20-015 and Town By-law 631-P-02-10, as amended by Bylaw No. 785-P-07-20.
3 Town of Coaldale, Town Plan, Bylaw No. 786-P-09-20.
South Coaldale Revised Area Structure Plan (Portion of Area North of 30th Avenue)
May 2021
Page 6
e)
Town of Coaldale Land Use Bylaw
The Land Use Bylaw4 describes the permitted land uses and land
use districts in the Town of Coaldale.
2. Relation to Other Plans
The Oldman River Regional Services Commission (ORRSC) produced the
original South Coaldale Area Structure Plan. This plan provided a
framework for development within an area generally south of the St.
Mary River Irrigation District (SMRID) Coaldale Lateral Canal, west of
Highway 845, north of the present Town boundary and east of the
extension of the alignment of 13 Street (this is shown on Figure 1.0). The
SCRASP revised the framework for a specific area within the boundaries
of the original ASP (this is shown on Figure 2.0). SCRASP supersedes the
existing ASP within the "site area" (as defined in Sub-section I.B). The
SCRASP (2021) represents an updated concept to the previously approved
SCRASP (2010).
Reason for Revision to the original ASP
2010 Revision
The South Coaldale Area Structure Plan (Bylaw No. 407-P-07-99) was
amended in 2010 to create the South Coaldale Revised Area Structure
Plan (Portion of Area North of 30th Avenue) (Bylaw No. 634-P-03-10).
Several assumptions used in preparing the original ASP were deemed
invalid when the ASP was revised in 2010:
-
The original ASP assumed that if density was kept to less than
the maximum permitted for the country residential land use
designation, there would be no requirement for specific
stormwater management plans, installation of detention
storage, or runoff control.5 Issues surrounding the Malloy Basin
and the recent Conveyance agreement executed between the
Town of Coaldale and SMRID6 have set specific requirements for
stormwater management (see Article IV.B.2) which make
implementation of the existing ASP untenable.
-
The existing ASP assumed that only a single intersection would
be permitted on Highway 845 between the Coaldale Lateral
Canal and the south Town boundary - at the existing Highway
845/30 Avenue/future Cottonwood Drive junction. Alberta
Transportation has since indicated that, provided traffic safety
requirements (sight lines, intersection geometry, spacing etc...)
4 Town of Coaldale, Land Use Bylaw, Bylaw No. 677-P-04-13.
5 Information provided by Steve Harty - ORRSC.
6 Stormwater Conveyance Agreement, between St. Mary River Irrigation District and Town of Coaldale
and County of Lethbridge, executed by SMRID and Town on 26 June.
South Coaldale Revised Area Structure Plan (Portion of Area North of 30th Avenue)
May 2021
Page 7
can be met for the road's gazetted speed limit (50 km/h), a
second access could be approved north of 30 Avenue (see Sub-
section IV.A).
-
The recent 13th Street Sanitary Sewer Twinning construction
that was extended to the South side of SMRID Canal has
capacity for new developments in the South Coaldale area for a
maximum gross density of 30 capita per gross hectare7. This is a
higher density than land use proposed in the existing ASP
would allow. Presently the Town does not permit sanitary
collection system extensions from the existing sanitary trunk on
30th Avenue due to capacity issues (see Article IV.B.1).
Additionally, a community meeting held in Coaldale on 12 November 2009
as well as prior and subsequent discussions with landowners within the
"site area" indicated that a revision allowing higher density development,
including re-development of existing agricultural businesses (e.g. the
Coaldale Egg Farm) would be desirable. Such higher-density land use
would be consistent with an urban municipality and with adjacent
development to the north and west (e.g. existing Town residential areas
and the proposed Cottonwood Estates development).
2021 Revision
SCRASP (2010) was amended to reflect the following:
-
A three-phase community engagement process to gather adjacent
landowner and resident input on the proposed future residential
development for the northeast portion of the site was implemented
from January to April 2021. The purpose of the engagement process
was to gather input on potential opportunities and concerns, review
and provide input into the draft concept proposed and collect
feedback to finalize the concept. Input gathered during this
engagement process was used, where appropriate, to prepare the
concept for the northeast portion of the site area.
3. Town Planning Process
Figure 3.0 shows, schematically, the planning process in the Town of
Coaldale with the highest-order legislation and the subsequent documents
and steps in the planning process. This process represents the statutes,
regulations and bylaws noted in Article I.A. Also, as noted in Article I.A.1,
once adopted by Town Council as a bylaw, an ASP describes the policies to
which all future land use re-designations and subdivisions within the
subject area must conform.
Figure 3.0 - Schematic of Coaldale's Planning Process
7 Information provided by Douglas Mickey - MPE Engineering Ltd.
South Coaldale Revised Area Structure Plan (Portion of Area North of 30th Avenue)
May 2021
Page 8
Section 1.19 of the Town Plan also requires the preparation of an Outline Plan to
be submitted at the redesignation or subdivision stage. An Outline Plan provide
more detailed information for a smaller portion of the site area, confirming
servicing, transportation, and environmental information to support development
of the lands
B. General Location and Plan Area
The plan area is located generally south of the existing residential areas of
Coaldale, within the Southwest Quarter of Section 11, Township 9, Range 20
West of the 4th Meridian (SW11-9-20-4). Generally, the area affected by the
SCRASP is located south of the SMRID Coaldale Lateral Canal, east of Highway
845 and the Cottonwood Estates development, north of 30 Avenue and west of 13
Street and the South Coaldale Drain. Specific lands affected by the SCRASP are
as described below. Figure 2.0 shows the SCRASP site area.
-
Remainder of SW11-9-20-4,
-
Lot 1, Block C, Plan 49 FJ
-
17 Street
South Coaldale Revised Area Structure Plan (Portion of Area North of 30th Avenue)
May 2021
Page 9
-
Lot 1, Block B, Plan 49 FJ
-
Lot 2, Block B, Plan 49 FJ
-
Lot 4, Block B, Plan 49 FJ
-
Lot 2, Block C, Plan 49 FJ and an unnamed road allowance to
the south
-
Lot 19, Block C, Plan 0213392
-
Lot 8, Block C, Plan 9411128
-
Lot 20, Block C, Plan 0312829
-
Lot 18, Block C, Plan 0210504
-
Block X, Plan 1540 GP
South Coaldale Revised Area Structure Plan (Portion of Area North of 30th Avenue)
May 2021
Page 10
II. Site Analysis
The following describes the existing condition of the "site area" defined in Sub-section
I.B. Figure 4.0 shows the existing topography, surface features and known utilities in
the site area.
A. Site Characteristics
Currently, the site area is relatively flat land (slopes are on the order of 1%).
Generally, the land slopes from west to east. Physical features within the site
area include:
-
The SMRID South Coaldale Lateral Canal along the north
boundary. An embankment separates the canal from the lands
adjacent. Culverts for road crossings exist at Highway 845 and
17 Street. A pedestrian bridge crosses at the south end of 13
Street.
-
The South Coaldale Drain is located along the east boundary
and south of the south boundary. It is crossed by several
culverts and small bridges along its length.
The low point of the site area is located near the northeast corner of Lot 1, Block
B, Plan 49 FJ - adjacent the South Coaldale Drain.
B. Soil Classification
According to the Alberta Soil Information Viewer, the following soils exist or
may exist within the site area:
Miscellaneous undifferentiated mineral soils (ZUN) and disturbed land (urban,
open pit mines, gravel pits) (DL).8
A Geotechnical Report will be required prior to Detailed Engineering Design
stage as part of the Town of Coaldale requirements for new developments.
C. Water and Hydrology
The site area (and Coaldale in general) is located within the catchment of the
Malloy Drain. This channel was constructed to convey irrigation return water
from the SMRID to Stafford Lake. Tributary to the Malloy Drain are the
Coaldale Lateral Canal and the South Coaldale Drain.
- The Coaldale Lateral Canal is located in a natural draw which extends
westward as far as the City of Lethbridge. This canal has its turnout from
the SMRID Main Canal approximately 4.1 km east of the Lethbridge City
Limit and approximately 1.2 km south of Highway 512 (Jail Road). East of
8 Alberta Soil Information Viewer, Soil Polygon #5882, URL:
http://www2.agric.gov.ab.ca/app77/imf.jsp?site=agrasid, retrieved: 6 May 2021.
South Coaldale Revised Area Structure Plan (Portion of Area North of 30th Avenue)
May 2021
Page 11
the SMRID Main Canal, the Coaldale Lateral flows east-northeast and
serves numerous agricultural water users and (due to its location in a
natural draw) drains upstream lands. Within the Town of Coaldale, the
canal deflects to an east-west alignment immediately east of the
Cottonwood Drive crossing. From this point the canal flows west-to east,
passing under Highway 845. East of 17 Street, the canal flows on an
embankment, above surrounding land. A spillway exists east of 13 Street
which allows high flows to be diverted into the adjacent South Coaldale
Drain. At the east Town boundary, the canal deflects northward, serving
lands in the County of Lethbridge east of Coaldale and, eventually,
discharging into the Malloy Drain.
- The South Coaldale Drain is an open channel that provides the major
drainage path for surface runoff north of Highway 512, east of Range Road
20-3 and south of the Coaldale Lateral. The drain begins south of Coaldale
and follows the west ditch of Highway 845 to 30 Avenue. Here, the drain
crosses under Highway 845 and follows the south ditch of 30 Avenue to 17
Street, where it crosses to the north ditch. The drain continues eastward
to the end of the 30 Avenue (at the extension of the alignment of 13
Street) where it deflects northward. The drain proceeds northward to the
embankment of the Coaldale Lateral Canal, where it deflects eastward. At
this location, the Coaldale Lateral spillway discharges into the drain. The
drain continues eastward into the County of Lethbridge, eventually
discharging into the Malloy Drain.
The Malloy Drain is managed by SMRID. In recent years, landowners adjacent
the Malloy Drain have experienced floods during long-duration storm events.
Concerns have been expressed by SMRID with respect to development in the
area. As such, obtaining licenses from Alberta Environment to construct new
development, as are required under the Water Act (Alberta), has become more
difficult. Recently, a conveyance agreement was reached between SMRID and
the Town of Coaldale detailing the requirements relating to stormwater
management in Coaldale. These are discussed further in Article IV.B.2
As stated in Sub-section II.A, the site area drains generally west to east. Over
the years, agricultural and country residential development in the area has
necessitated the construction of dugouts for stock and land irrigation and ditches
for drainage of runoff. The lowest point in the site area is located near the
northeast corner of Lot 1, Block B, Plan 49 FJ, where a draw exists which
discharges into the adjacent South Coaldale Drain.
Infiltration of water from the Coaldale Lateral has required the owners of the
two adjacent parcels (Lot 1, Block B, Plan 49 FJ and Lot 1, Block C, Plan 49 FJ)
to construct a piped drainage system on their land. Land in the northeast part of
Lot 1, Block B, Plan 49 FJ along the canal embankment can be wet or have a
seasonally high water table, likely due to infiltration from the canal.
South Coaldale Revised Area Structure Plan (Portion of Area North of 30th Avenue)
May 2021
Page 12
D. Habitat and Vegetation
The plan area consists mainly of mixed grasses that produce a hay crop and is also
used for grazing purposes. There are mature trees scattered throughout the site,
encircling many farmstead buildings. A variety of grasses and brush are
intermixed with the trees, providing habitat for birds and small animals.
E. Environmental, Historical and Archaeological
Significance
The land has been continuously developed as agricultural and small acreages
since the late 19th Century. The original ASP notes no locations of
environmental, historical or archaeological significance.
F. Existing Land Use
Generally, land use in the area is either agricultural (including an egg farm,
cattle feed lot and pastures), single-family residential and country
residential/small acreages. Figure 5.0 shows the designations as noted in the
Town of Coaldale Land Use Bylaw at the time of printing. While a portion of the
lands are zoned as R-2, they are currently being used for agricultural purposes
(egg farm).
G. Constraints
The site area places the following constraints on development:
1. Stormwater Management and Drainage
The site's location within the Malloy Basin and the Town of Coaldale
places several important constraints on development:
a) A sizable area must be set aside for stormwater detention and
treatment;
b) Overflows from the South Coaldale Drain could inundate low areas
unless backwater controls are constructed;
c) The elevation of the South Coaldale Drain dictates that no storm
sewers can have inverts below 861.5 m (unless a lift station is
constructed);
d) Infiltration from the Coaldale Lateral may cause high groundwater in
some areas unless acceptable interception and conveyance is
constructed;
e) Drainage routes must be defined and preserved between multiple
landowners.
2. Sanitary Sewer Capacity
The 13th Street Sanitary Sewer Twinning project (constructed in 2009)
was extended to the South side of SMRID Canal. This sewer has capacity
South Coaldale Revised Area Structure Plan (Portion of Area North of 30th Avenue)
May 2021
Page 13
to allow new development to a maximum gross density of an average of 30
people per hectare across the entire site area. At the time of the 2010 ASP
revision, the Town did not permit sanitary collection system extensions
from the existing sanitary trunk on 30th Avenue due to capacity issues.
3. Access and Circulation
There are presently only two accesses to the area from outside:
-
30 Avenue running east-west that connects to Highway
845 and
-
17 Street running north-south that extends across the
canal connecting to the downtown.
Although an additional public access from Highway 845 may be feasible,
Highway 845 is a provincial highway and, as such, is controlled access.
Therefore, no direct accesses to private property will be permitted from
Highway 845 (existing accesses are permitted until such time as
subdivision occurs). As such, all new lots will have to access an internal
road network and circulation though the site area must be maintained for
all landowners as the area develops.
4. Existing Irrigation Infrastructure
Much irrigation infrastructure (canal, pipes, drains and dugouts) is
covered by a blanket or statutory easement which does not specify the
location on a given parcel of land. As subdivision takes place on land with
irrigation infrastructure it would be preferable to have a separate right-of-
way registered for the irrigation work or to relocate it to an existing right-
of-way. Individual landowners/developers and SMRID will need to work
cooperatively in this regard. In addition, when irrigation infrastructure
are no longer required they should be regraded and consolidated with
adjacent property where feasible.
H. Opportunities
Redevelopment of South Coaldale presents the following opportunities.
1. Encouragement of Compatible Land-Uses
Presently, intensive agriculture operations (an egg farm and a cattle feed
lot) exist immediately adjacent existing single-family residential
development. These two land uses would not generally be considered
compatible. The SCRASP permits these lands to be redeveloped into
residential uses. Further south and east, a mix of residential uses are
envisioned, with single-family residential development immediately
adjacent to existing country residential properties in the southeast of the
plan area, transitioning to medium-density in the northeast of the plan
area.
South Coaldale Revised Area Structure Plan (Portion of Area North of 30th Avenue)
May 2021
Page 14
2. Permitting More Choice in Housing
The plan allows a mix of residential land uses, including low- and
medium-density and seniors housing, appropriate for families, young
professionals, seniors and others who desire a variety of affordable and
appropriate housing options that meet their specific needs.
3. Proximity to Services
Two schools are located in close proximity to the site area:
-
St Joseph's School (Holy Spirit Roman Catholic Separate
Regional Division No 4.) at 1413 - 23 Avenue.
-
Jennie Emery Elementary School (Palliser Regional
School District) at 1101 - 22 Avenue.
Coaldale's central business area is only 10 blocks north. The Town softball
fields (Quads-Baseball and Soccer Fields) are located immediately east
across the South Coaldale Drain.
4. Additional Parks and Open Space
The requirement for stormwater management means land will need to be
set aside for public use. The design of the stormwater facilities (see Article
IV.B.2) is intended to provide a scenic "lake" area surrounded by public
pathways. It is intended that these pathways connect with existing
pathways from 13 Street and along the Coaldale Lateral Canal. In
addition, the stormwater facility is located immediately adjacent an
existing Town park (the Quads-Baseball and Soccer Fields east of the
South Coaldale Drain).
Development within the site area is intended to provide for internal
pathways to allow pedestrian circulation and access to open space. An
east-west pathway and open space along the southeast boundary of the
plan area is to be included to support additional connectivity through the
ASP area and provide a buffer between existing country residential and
new single-family residential.
South Coaldale Revised Area Structure Plan (Portion of Area North of 30th Avenue)
May 2021
Page 15
III. Proposed Land Use and Design
A. Proposed Land Use
Land uses proposed within the site area are intended to allow a variety of
choices in residential development to meet the needs of all residents and to
support aging in place. Generally, the following land uses are proposed:
Low-density residential: much of the development will consist of low-density
residential lots. Lot sizes of between 540 m2 and 2104 m2 (0.13 to 0.52 acre) are
proposed.
Medium-density residential: medium-density residential development is
proposed for Lot 1, Block B, Plan #49FJ and the north portion of Lot 2, Block B,
Plan #49FJ. These areas are intended for a mix of low-rise apartment buildings
and row housing. Lot 1, Block C; Plan #49FJ (the egg farm) development will
consist of 24 units in a collection of three-plex and four-plex condominium
buildings on the 1.54 ha (3.81 acre) parcel.
Seniors housing: a seniors housing complex is planned for the northwest portion
of Lot 1, Block B, Plan #49FJ.
The proposed land uses are shown on Figure 6.0.
The ASP does not designate land use to a parcel. Prior to development, the
subject lands will need to be re-zoned to the appropriate district, except for areas
of the plan where the appropriate land use is already designated.
B. Population and Housing Densities
Table 1 details the projected population within the site area, if developed
according to land uses noted in Figure 6.0. The maximum gross density of an
average of 30 persons per hectare across the entire site imposed for South
Coaldale by the downstream sanitary sewer's capacity is noted.
Table 1.0 - Population and Housing Densities
Legal Description:
Area (ha)
Projected Lots
Projected Population
Lot 1, Block B, Plan 49FJ
4.74
178
283
Lot 2, Block B, Plan 49FJ
4.74
50
125
Lot 2, Block C, Plan 49FJ
2.36
17
51
Parcel X, Plan 1540GP
3.24
18
54
Lot 18, Block C, Plan 021 0504
0.89
4
12
Lot 20, Block C, Plan 031 2829
0.42
2
6
Lot 8, Block C, Plan 941 1128
0.89
4
12
Lot 19, Block C, Plan 021 3392
0.51
6
18
Lot 4, Block B, Plan 49FJ
1.37
13
39
SW ¼ Sec. 11-9-20-W4M
1.20
8
24
Lot 1, Block C, Plan 49FJ
1.53
25
75
Total:
21.89 ha
325
699
South Coaldale Revised Area Structure Plan (Portion of Area North of 30th Avenue)
May 2021
Page 16
IV. Proposed Infrastructure
To implement the SCRASP, the following new infrastructure is proposed.
A. Access and Circulation
1. Highway 845 Access
To provide access to all existing and proposed properties, given the
restriction on private access to Highway 845, an internal road network is
proposed. This is shown on Figure 7.0. As noted, a new all-turns
intersection is proposed for Highway 845 approximately 180 m north of
the existing Highway 845/30 Avenue intersection. Ongoing discussion
with Alberta Transportation will determine the specific intersection
treatment required at this location. The gazetted speed limit along this
section of Highway 845 is 50 km/h. Access to Highway 845 requires
approval of Alberta Transportation.
2. Other Connections
Additional existing accesses to the site area from 30 Avenue and the 17
Street/Coaldale Lateral Canal crossing appear adequate for the proposed
population density noted in the SCRASP. A Transportation Impact
Assessment9, completed in 2021 for the South Coaldale area, confirmed
that additional traffic anticipated to be generated by the proposed
development can be accommodated by the existing road network over the
next 20 years.
To further support connectivity within and to the northeast portion of the
site area, including the Quads-Baseball and Soccer Fields, and support
implementation of recommendations from the Town's Transportation
Master Plan10, 13 Street is to be extended north from 30 Avenue to
connect to proposed 28 Avenue, with a second access to the Quads
provided, as shown in Figure 7.0.
3. Internal Roads
Roadways will be developed to Town of Coaldale standards.
4. Pathway Connections
As noted, there are numerous opportunities to provide a new
comprehensive public pathway network within the site area itself and
provide connections to existing pathways. Pathway Plan will be outlined
in Development Agreement.
9 Town of Coaldale, South Coaldale Transportation Impact Assessment, 2021
10 Town of Coaldale, Transportation Master Plan, 2021
South Coaldale Revised Area Structure Plan (Portion of Area North of 30th Avenue)
May 2021
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B. Public Utilities and Servicing
1. Sanitary Sewers
The sanitary servicing scheme is shown on Figure 8.0. The ultimate
connection point is a manhole on the east side of the South Coaldale
Drain, approximately 100 m south of the south end of 13 Street. This
manhole is at the present high end of a 375-mm diameter trunk sewer. Its
invert elevation is 857.84 m.11 As stated earlier, this trunk sewer is meant
to serve the South Coaldale area (both north and south of 30 Avenue) to a
maximum average population density of 30 people per gross hectare
across the site. In 2021, a study12, that reviewed sanitary capacity in
South Coaldale, found that development proposed within the SCRASP site
area, plus approved development in the Seasons, Fieldstone Meadows and
the last phase of Cottownwood, can be accommodated by the existing
sanitary system before any major sanitary upgrades will be required.
Table 2.0 shows an initial design for the sanitary sewers serving the site
area. This is provided to confirm the following:
- That there is adequate downstream capacity in the existing trunk
sewer to serve the proposed development,
- That adequate grade exists within the site and the existing sanitary
trunk sewer to provide gravity sanitary sewers to serve the
proposed development.
It must be noted that conservative assumptions were used in Table 2.0.
Design of sanitary sewers will be done at the development permit/detail
design stage.
2. Drainage and Stormwater Management
Proposed drainage and stormwater management for the SCRASP is
shown on Figure 9.0.
a)
Stormwater Detention
As stated, the subject area is surface-drained. Much of the land is
tributary to the South Coaldale Drain (a small area drains directly
to the Coaldale Lateral Canal). As the area (same with all of
Coaldale) is part of the Malloy Basin, certain special standards
apply to new drainage works. As part of these conditions, the Town
has entered into an agreement with SMRID to convey stormwater
to Stafford Lake. It is understood that SMRID specifically requires
the following:
11 Based on topographic and utility survey by MGCL, March 2010.
12 Town of Coaldale, Infrastructure Master Plan, 2021
South Coaldale Revised Area Structure Plan (Portion of Area North of 30th Avenue)
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- that detention storage be provided on-site to detain all runoff
resulting from a 100-year design storm,
- that controls be provided on the discharge from detention
facilities such that flow from these facilities can be stopped until
such time as conveyances downstream to Stafford Lake can
accommodate this flow.
Given this, a preliminary plan was made with respect to sizing a
storm detention facility within the plan area. A catchment
boundary was drawn to include the plan area as well as adjacent
rear yards and part of the Highway 845 right-of-way. This area was
assumed to drain to a new storm detention facility located in the
east portion of the plan area, immediately adjacent the South
Coaldale Drain. This drainage area was estimated at approximately
27 ha (21.9 ha within SCRASP, 6.1 ha of offsite area). The 100-year
storm event (109 mm of rainfall in 24 hours) generated 24,500 m3
(approximately 90 mm) of runoff. This was assumed to be the
volume that must be detained by the storm detention facility. As
can be seen, the existing ground contours indicate that, in general,
runoff will flow toward the proposed pond location.
b)
Runoff Conveyance
Due to the topography and density of development proposed in the
SCRASP, a dual drainage system is proposed for the plan area - as
opposed to the previously proposed surface drainage system. The
dual drainage system will be designed as follows:
- The major or overland drainage system will be designed to catch
runoff from the buildings and streets and convey it to the
nearest minor system (storm sewer) inlet or catch basin.
Elements of the major system include roof leaders, grassed
areas, swales, lanes, road gutters, pathways and other open
channels. This system is designed to safely convey peak runoff
resulting from a 100-year return period design storm event.
Depths and velocities of runoff in major system conveyances
(particularly streets, lanes and pathways) are checked against
Provincial and Town guidelines to ensure the protection of the
public safety, the environment and property - as well as
roadway level-of-service criteria.
- The minor or storm sewer system is designed to drain low areas
of roads (trapped lows) and other areas where runoff may pond,
spread unacceptably or otherwise create a nuisance. Elements of
the minor system consist of drainage inlets (headwalls, catch
basins, street grates), subdrains (weeping tile, French drains),
pipes and manholes. This system is designed to convey runoff
South Coaldale Revised Area Structure Plan (Portion of Area North of 30th Avenue)
May 2021
Page 19
resulting from a 5-year storm event without surcharging (e.g.
water levels in pipes do not exceed the pipe's depth/diameter).
- The minor system is also often used to convey drainage from
building foundations. Present practice in greater Lethbridge
discourages the use of inlet control devices (ICDs) in street catch
basins to prevent surcharges as they cause maintenance
problems. As such, storm sewers are subject to surcharge in
events more frequent than the 100-year storm; therefore, no
building foundation drainage system should be directly
connected to the storm sewers except by means of a sump and
pump with a check valve consistent with City of Lethbridge
standards.13 An alternative to the storm sewer connection is to
pump from the sump to a splash pad located as per City of
Lethbridge standards.14
c)
Low-impact Development (LID)
In an effort to reduce the impact of development on surrounding
lands and the downstream drainage system, developers within the
SCRASP are strongly encouraged to implement low-impact
development best management practices (LID BMP). These can
take many forms. The Alberta Low-Impact Development
Partnership (ALIDP) is a resource that should be consulted as part
of planning LID. Proposed LID features and their effects on the
storm drainage system should be addressed in consultation with
the Town at the detail design stage. LID BMPs may become a
mandatory requirement in the Town of Coaldale.
3. Potable Water
The conceptual potable water servicing scheme is shown on Figure 10.0.
a)
Connection Points
Proposed connections for the potable water system at the following
locations:
i. To the existing 300-mm diameter trunk water main in 30
Avenue at the intersection of 30 Avenue and 17 Street,
ii. Extension of the existing 150-mm diameter watermain in 17
Street south under the Coaldale Lateral Canal
These will be confirmed with the Town's water distribution system
model to ensure an adequate level of service is achieved.
13 City of Lethbridge, Design Standards, 2009, §9.1.4.2
14 Ibid.
South Coaldale Revised Area Structure Plan (Portion of Area North of 30th Avenue)
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b)
Internal Looping
The main looping will be provided by the connection of the 30
Avenue trunk watermain to the existing watermain in 17 Street.
Internal looping and valves will be constructed such that a main
shut-down will not affect more than 30 homes.
c)
Predicted Demand
Given the proposed population of 492 people, average daily demand
for the subject area at full buildout is predicted to be 204 m3 (based
on City of Lethbridge 2009 Design Standards).
d)
Design Standards
All new watermains within the site area will be 200-mm diameter
or larger. Hydrants will be located as required to ensure a clear
travel distance to all lots does not exceed 90 m. The proposed
distribution system will be confirmed with the Town's water
distribution system model to ensure an adequate level of service is
achieved.
Any required canal under-crossings will be constructed as per
SMRID's requirements.
4. Community Irrigation System
Given the subject area's proximity to the Coaldale Lateral Canal, the
opportunity exists for a community irrigation system to be designed to
serve this area. Indeed, several landowners within the SCRASP boundary
are served by SMRID. A community irrigation system may provide a
significant long-term benefit to the Town by decreasing the demand for
potable water for uses such as yard and park irrigation. Such a system
exists in the adjacent Cottonwood Estates subdivision.
A community irrigation system would use water from the storm pond as
its primary source. SMRID would be the secondary source. The Town
encourages the developers in the area to form a water co-operative to
provide this service.
5. Shallow Utilities
a)
Natural Gas
ATCO Gas will be provided to all newly developed lots as part of a
4-party shallow utility servicing within the front-yard utility right-
of-way.
South Coaldale Revised Area Structure Plan (Portion of Area North of 30th Avenue)
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b)
Electrical
FORTIS Alberta underground electric power service will be
provided as part of 4-party shallow utility servicing within the
front-yard utility right-of-way. Street lighting will be provided
consistent with the Town's agreement with FORTIS.
c)
Telephone
Telus underground telecommunications cable will be provided as
part of 4-party shallow utility servicing within the front-yard utility
right-of-way.
d)
Cable Television
Shaw Cable television (CATV, internet, etc...) will be provided as
part of 4-party shallow utility servicing within the front-yard utility
right-of-way.
C. Solid Waste
Solid waste pickup will be provided by the Town of Coaldale.
South Coaldale Revised Area Structure Plan (Portion of Area North of 30th Avenue)
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Table 2.0 - Preliminary Sanitary Sewer Design
South Coaldale Revised Area Structure Plan (Portion of Area North of 30th Avenue)
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V.Subdivision and Development Staging
Development will be staged based on individual landowners' subdivision plans. The
plan provided in the ASP allows owners to develop while still ensuring servicing and
access to adjacent owners is preserved. Minor modifications to lot sizes shall be allowed
without requiring an amendment to the ASP.
VI. Development Control
Purchasers must apply for development approval according to the process in effect for
the appropriate Land Use District in the Town of Coaldale Land Use Bylaw in effect at
the time of application.
VII. Development Agreements
At the time of subdivision, the Developer will be required to enter into a Development
Agreement with the Town of Coaldale.
VIII. Architectural Control Guidelines
The developer will be required to submit Architectural Control Guidelines to the Town
of Coaldale for approval.
South Coaldale Revised Area Structure Plan (Portion of Area North of 30th Avenue)
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Appendix A - Included Figures
The following figures are referenced in the text.