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Town of Coaldale
West Coaldale Area Structure Plan Bylaw 856-P-07-22
March 27, 2023
BYLAW 856-P-07-22
TOWN OF COALDALE
PROVINCE OF ALBERTA
BEING A BYLAW OF THE TOWN OF COALDALE
TO AMEND BYLAW 512-P-04-03,
BEING THE WEST COALDALE AREA STRUCTURE PLAN
WHEREAS the municipal council is in receipt of an application to amend the West
Coaldale Area Structure Plan (Bylaw 512-P-04-03) within the municipality.
AND WHEREAS the purpose of the proposed amendment is to execute a number of text
amendments intended to propose a change in the neighbourhood design and dwelling
types within lands located within the NW10-09-20-W4M in the Town of Coaldale as shown
in Schedule A.
AND WHEREAS all changes to the ASP as generally described are identified specifically
in "Schedule A" attached hereto.
AND WHEREAS the municipality must prepare an amending bylaw and provide for its
consideration at a public hearing.
NOW THEREFORE, under the authority and subject to the provisions of the Municipal
Government Act, Revised Statutes of Alberta 2000, Chapter M-26, the Council of the
Town of Coaldale, in the Province of Alberta, duly assembled does hereby enact the
following:
1.
The West Coaldale Area Structure Plan amendments referenced above and
identified specifically in "Schedule A" shall make up the amended West Coaldale
Area Structure Plan.
2.
Bylaw 512-P-04-03, being the West Coaldale Area Structure Plan, is hereby
amended.
3.
This bylaw comes into effect upon third and final reading hereof.
READ a FIRST time this 25th day of July, 2022 for West Coaldale Area Structure Plan
Bylaw 856-P-07-22.
____________________________
____________________________
Mayor - Jack Van Rijn
CAO - Kalen Hastings
Motion #: 295-2022
Page 2 of 2
Town of Coaldale
West Coaldale Area Structure Plan Bylaw 856-P-07-22
March 27, 2023
Public Hearing for West Area Structure Plan Rezoning Bylaw 856-P-07-22 was
scheduled to be held at 5:15 p.m. at the Regular Council Meeting on March 27th,
2023.
READ a SECOND time this 27th day of March, 2023 for West Coaldale Area Structure
Plan Bylaw 856-P-07-22.
____________________________
____________________________
Mayor - Jack Van Rijn
CAO - Kalen Hastings
Motion #: 90-2023
READ a THIRD and FINAL time this 27th day of March, 2023 for West Coaldale
Area Structure Plan Bylaw 856-P-07-22.
____________________________
____________________________
Mayor - Jack Van Rijn
CAO - Kalen Hastings
Motion #: 91-2023
West Coaldale
Amended 2023
AREA STRUCTURE PLAN
Prepared for:
Domenic Land Development
NW1
4 Sec.10 - 9 - 20 - W4M
Prepared by:
Martin Geomatic Consultants Ltd.
229648CE
N
Land-O-Lakes
Golf Course
Hwy 3
Town of
Coaldale
Range Road 203
Amendment 2023
West Coaldale Area Structure Plan, Amended 2023
Introduction
To prepare the West Coaldale Area Structure Plan version of the plan, we are proposing
major changes in Section 4.0, minor changes to all other sections and eliminating.
Appendices 1, 2, 3, and 4.
The 2023 ASP has included Figure 1.0- Existing Land Use, Figure 2.0 - Proposed Land Use,
Figure 3.0 -Conceptual Road Network, Figure 4.0 - Underground Utilities, Figure 5.0 -
Stormwater Management Pre-development, and Figure 6.0 - Stormwater Management Post-
development. Appendix A - Table Showing the Existing and Proposed Densities. The results
of the Town of Coaldale public engagement are included as Appendix B.
Section 1.0 from the 2003 version of the ASP is an introduction, focusing on background
information and processes for the ASP approval.
Section 2.0 from the 2003 version reviews ASP versions from 1996 and 1998.
Section 3.0 outlines issues that should be addressed in the ASP. These issues will be
addressed in Section 4.0 of the 2023 ASP.
In reviewing Sections 1.0, 2.0, and 3.0 of the 2003 ASP there are no major changes
required. These sections mainly address process and basic information regarding ASPs in
general. Therefore, we are not proposing any major changes to these sections.
Section 5.0 and 6.0 tend to outline basic and general development processes and polices
that are common for the most ASP's and most developments and are not really site specific.
Therefore, we are not proposing major changes to the text in Section 5.0 and 6.0.
Section 4.0 Design Scheme has been rewritten to reflect the changed elements of planning,
land uses, conceptual layout, roadways, and utility servicing. Additionally, the changes
reflect developments that have occurred between 2003 and 2023 with no amendments to
the conceptual. Also shown in Section 4.0 are changes because of current concerns,
landowner plans, and solutions to items in storm water management.
Figure 1.0 represents the existing Land Uses and Figure 2.0 shows the proposed land uses.
This new concept includes changes that have been made in the layout from previous
updated Maps. The primary change is a revised concept in the southwest portion of the ASP
area. Changes to the concept have been crafted in conjunction with the administration of
the Town of Coaldale.
Amendment 2023
TABLE OF CONTENTS
West Coaldale Area Structure Plan
Amended 2023
1.0
INTRODUCTION .............................................................................. 1
1.1
Background ........................................................................... 1
1.2
Location ................................................................................ 1
1.3
Purpose and Intent of the Plan ................................................. 2
1.4
Legislative Requirements ........................................................ 2
1.5
Process ................................................................................. 3
1.6
Goals .................................................................................... 3
2.0
PREVIOUS DESIGN PROPOSALS - REVIEW ......................................... 4
2.1
1996 Design Proposal ............................................................. 4
2.2
1998 Design Proposal ............................................................. 4
2.3
2003 West Coaldale Area Structure Plan ................................... 5
2.4
2023 West Coaldale Area Structure Plan ................................... 6
Amendment 2023
3.0
DESIGN CONSIDERATIONS .............................................................. 6
3.1
Existing Land Use ................................................................... 6
3.2
Potential Land Uses ................................................................ 7
3.3
Landowner Input ................................................................... 7
3.4
Road Network ........................................................................ 7
3.5
Stormwater Management ........................................................ 8
3.6
Utilities ................................................................................. 8
4.0
DESIGN SCHEME (AMENDED 2023) ................................................... 9
4.1
Type Of Development ........................................................... 10
4.1.1 Housing Types ............................................................ 10
4.1.2 Highway Commercial Development .......................................... 11
4.1.3 School Site .................................................................. 12
4.1.4 Parks and Open Space .................................................... 12
4.2
Storm Water Management .................................................... 13
4.3
Road Network ...................................................................... 14
4.3.1 Existing Transportation Impact Assessments (TIA) .......... 14
4.3.2 Roadways ................................................................... 15
4.3.3 New TIA ..................................................................... 15
Amendment 2023
4.4
Utility Servicing .................................................................... 15
4.4.1 Water Distribution System ............................................ 16
4.4.2 Sanitary Sewer System ................................................ 16
4.4.3 Street Lighting ............................................................ 16
4.4.4 Shallow Utilities ........................................................... 16
4.4.5 Phasing ...................................................................... 17
4.5
Neighborhood Comments ...................................................... 17
4.5.1 Open House, March 2, 2022.......................................... 17
4.5.2 Open House, February 2023 ......................................... 20
5.0
OTHER SUBDIVISION AND DEVELOPMENT ISSUES............................ 22
5.1
Off-site Levies and Development Fees..................................... 22
5.2
Municipal and School Reserve ................................................ 22
5.3
Architectural Control ............................................................. 23
6.0
SEQUENCE OF DEVELOPMENT OF LAND ........................................... 24
6.1
Reclassification of Land ......................................................... 24
6.1.1 Process ...................................................................... 24
6.1.2 Policies ....................................................................... 24
Amendment 2023
6.2
Subdivision and Development of Land ..................................... 25
6.2.1
Process ........................................................................ 25
6.2.2 Policies ....................................................................... 25
6.3
Development of Individual Lots .............................................. 27
6.3.1 Process ...................................................................... 27
6.3.2 Policies ....................................................................... 28
CLOSURE .................................................................................... 29
APPENDIX A- FIGURES
FIGURE 1 - EXISTING LAND USE
FIGURE 2 - PROPOSED LAND USE
FIGURE 3 - CONCEPTUAL ROAD NETWORK
FIGURE 4 - UNDERGROUND UTILITIES
APPENDIX B - TABLES
Table Showing Existing and Proposed Densities
APPENDIX C - STORMWATER MANAGEMENT PLAN
Stormwater Management Plan
1
Amendment 2023
1.0 INTRODUCTION
1.1
Background
There have been ongoing discussions between the Town of Coaldale and individual
landowners since 1996 regarding the preparation an Area Structure Plan to provide
guidelines for further and future development of an underdeveloped area located in
west Coaldale. UMA Engineering, on behalf of a landowner, in 1996 proposed a plan
based primarily on single-family residential parcels (R-1 A) with a small centrally
located commercial hub. At that time, the proposed design scheme was not adopted.
Another attempt was made in 1998 when Plains West Planning Services Ltd.
reviewed the original preliminary design on behalf of the Town and recommended
changes to the proposal. The amended proposal attempted to address many of the
basic goals the Town identified in its General Municipal Plan as well as other
engineering and planning documents. As well, that design concept was not adopted.
Again in late 2001, a number of landowners indicated to the Town that they were
interested in developing the area and asked Council to resume the process to
develop an Area Structure Plan. As a result, Council requested their planning
advisors, the Oldman River Intermunicipal Service Agency (ORISA), in consultation
with MPE Engineering, to proceed with preparing a plan for the area. The resulting
Area Structure Plan will provide the framework for future development of this area.
Since 2003 ASP, approximately half of the site has been developed without an ASP
amendment. Thus providing a comprehensive planning framework to complete the
development.
This ASP is being prepared to update the planning and technical information required
to develop the ASP site.
1.2
Location
The West Coaldale Area Structure Plan 2003 refers to lands contained within the NW
10-9-20-W4, which lies west of 25 Street, south of Highway 3, north of the golf
course, and east of 30 Street (see Figure 1.0, Existing Land Use). Within the plan
boundary, the area is approximately 98.80 acres (39.98 ha).
The boundaries of this 2023 amendment ASP remain the same as the 2003 ASP. The
underdeveloped land as well as the existing developed land is shown together within
the ASP boundaries in Figure 2.0, Proposed Land Uses.
2
Amendment 2023
1.3
Purpose and Intent of the Plan
An Area Structure Plan is a planning document used to regulate future subdivision
and development in a specified area. More specifically, this Area Structure Plan is a
means to set the stage and outline the guidelines for the guidelines residential,
commercial and institutional growth and development. Development in the western
portion of Coaldale presents the Town with many opportunities to change and
improve the community as well as encourage economic growth within the Town.
This Area Structure Plan will address a number of issues including:
land uses and area designations,
provision of a wide range of housing types,
storm water drainage management,
utility corridors and municipal servicing,
future lot sizes and design layout,
roads and transportation patterns,
as well as a sequence of development implementation process.
The purpose of the plan is not to force or require subdivision and development, but rather to set out
guidelines for landowners and developers to follow if and when they decide to develop their lands. The
plan also provides some reasonable certainty to interested parties as to what type of future
development will be allowed in specified areas. Therefore, new lots should be designed in order to serve
the needs of a range of residential housing and a variety of highway commercial uses.
1.4
Legislative Requirements
An Area Structure Plan is a planning tool adopted by municipalities pursuant to
section 633 of the Municipal Government Act Revised Statutes of Alberta 2000,
Chapter M-26 (MGA). An Area Structure Plan is used in conjunction with both the
Municipal Development Plan and Land Use Bylaw to facilitate subdivision and
development in a specific area. In conforming to the legislation, an Area Structure
Plan must:
describe the sequence of development proposed for the area,
the land uses proposed for the area,
the density of the proposed area,
and the general location of transportation routes and public utilities.
3
Amendment 2023
It may also address any other matters Council deems necessary. An Area Structure
Plan must also be consistent with other statutory documents, such as the Municipal
Development Plan.
The Municipal Government Act also authorizes a notification and circulation process
pursuant to section 636, which states that while preparing a statutory plan, a
municipality must provide a means for any person who may be affected by the plan
to make suggestions.
1.5
Process
The 2003 ASP was prepared by the Oldman River Intermunicipal Agency (ORISA),
the Town of Coaldale and the Town engineers (MPE) together with consultation with
effected land owners.
This 2023 amended ASP will update the 2003 version incorporating public feedback
from a public consultation held by the Town in March of 2023. Since 2003 the Town
has developed new policies and has updated the Land Use Bylaw.
1.6
Goals
This Area Structure Plan will seek to accomplish the following:
(a) to accomplish orderly and contiguous land development;
(b) to provide land owners with a comprehensive plan that will set the guidelines for
appropriate land use and facilitate the orderly, economic and practical
development and subdivision of the subject lands;
(c) to enhance storm water drainage control through efficient and economical storm
water management and containment practices;
(d) to provide for a comprehensive range of residential, institutional and highway
commercial land uses;
(e) to provide Council, the Subdivision Authority and the development authority with
sufficient information to make planning decisions which will lead to the orderly,
economic and aesthetic subdivision and development of the subject lands;
(f) to inform land owners and interested parties of the process involved and the
commitments expected of them when endeavoring to subdivide and/or develop;
(g) to provide a design which integrates land uses with the requirements for
transportation patterns and other utilities across the entire plan area;
(h) to address many of the basic goals of the Town identified in its community
growth objectives, Municipal Development Plan and other engineering and
planning documents.
4
Amendment 2023
2.0 PREVIOUS DESIGN PROPOSALS - REVIEW
2.1
1996 Design Proposal
In 1996, UMA on behalf of one of the landowners proposed a design concept that
was primarily single-family residential (R-1 A) parcels with a small centrally-located
commercial hub (see Diagram 2). At that time, the Town did not proceed with the
formal preparation and adoption of an Area Structure Plan.
2.2
1998 Design Proposal
In 1998, Plains West Planning Services Ltd., MPE Engineering Ltd. and Town of
Coaldale Planner/ Development Officer reviewed the initial design at the request of
Town Council. Although comprehensive in many ways, the review found the
proposed 1996 concept design fell short of municipal expectations and failed to
address many of the basic goals identified by the Town in its General Municipal Plan.
5
Amendment 2023
Overall, the recommendation by Plains West Planning Services was to develop a new
design concept (see Diagram 3) that included:
a mixture of residential types (single family, multi family, seniors housing),
a strip of highway commercial use located on the northern portion of the area
adjacent to Highway 3,
the addition of a school site, and
a plan that will provide adequate on-site storm water storage to conform to
the recommendations of the 1994 Town of Coaldale Storm Water Flood
Control Project for the proposed ''West Detention Pond".
2.3
2003 West Coaldale Area Structure Plan
In 2003 the ASP for this site was amended based on new Town Policies, new land
owner requirements and new infrastructure upgrades.
6
Amendment 2023
2.4
2023 West Coaldale Area Structure Plan
This new West Coaldale ASP 2023 Amendments will update and amend the 2003 ASP
addressing new Town policies, new infrastructures since 2003 and new landowner
requirements. Additionally about one half of the site is now developed and this
development will be incorporated into the ASP.
3.0 DESIGN CONSIDERATIONS
The following polices have been incorporated into this revised ASP. The policies that
the Town has instituted and that have been addressed in this new ASP include:
Town of Coaldale Strategic Plan
The City of Lethbridge and Town of Coaldale Intermunicipal Development Plan
(Bylaw No. 785-P-07-20)
The amended Municipal Development Plan of 2020 (Bylaw No. 786-P-09-20)
Parks and Trails Master Plan (2008)
Gateways and Corridors Strategic Plan
Transportation Master Plan (2021)
Malloy Master Drainage Plan (2019)
Recreation Master Plan (2010)
Infrastructure Master Plan (2019)
Land Use Bylaw No. 677-P-04-13
This amended ASP has been reviewed by the Town administration and will be
presented to Council for First Reading. Before this ASP is adopted, a mandatory
public hearing must be advertised and then held. Once adopted, this plan will be
used to guide development of this ASP area.
3.1
Existing Land Use
The lands proposed to be included in the plan area are situated in West Coaldale -
west of 25th Street, east of 30th Street, north of the golf course and south of
Highway 3. The Coaldale tree nursery is located in the NW corner of the site with the
church being immediately east of this. The land between the nursery and the golf
course is currently underdeveloped. The land east of these properties have been
developed for highway commercial and single family residential use. The current land
uses are presented in Figure 1.0, Existing Land Use.
7
Amendment 2023
3.2
Potential Land Uses
As the plan area is over 98 acres and is largely undeveloped, this presents the
opportunity to create a comprehensive land use plan that caters to a wide variety of
community needs. The area is also uniquely located between the golf course
property and the highway. This will allow for a wide range of land uses to be
encouraged and also ''fit" with the existing layout, including the considerations of
mixed residential use south and in proximity of the golf course, commercial adjacent
to the highway and various public and institutional uses.
This type of plan will give the Town of Coaldale an opportunity to create an
interesting and desirable neighborhood for the community. It will also enable the
Town to achieve a number of economic, community and long range planning goals.
Proposed land uses are depicted in Figure 2.0, Existing Land Use.
3.3
Landowner Input
The Town and Developer have undertaken the task of getting opinions and
recommendations from adjacent land owners and other members of the community.
This process is addressed in more detail in Section 4.5 Neighborhood Comments and
Appendix C.
3.4
Road Network
The area is currently somewhat constrained, as it has limited through roads granting
access. Presently the landowners of the area are limited to gain access by either 24
or 25 Streets to the east and 30 Street to the west. The north portion of the lots
front onto Highway 3, with a service road partially built from 25 Street, west to the
church property. The parcels are land locked from the south as they are directly
north of the boundary of Land-0-Lakes Golf Course. The transportation issues with
respect to the residential and highway commercial sites in addition to Highway 3
access needs to be assessed.
Proper consideration needs to been given to addressing transportation concerns and
facilitating efficient traffic flow. When this area is developed, it would be logical to
extend 23 Avenue from the east to the west, to meet 30 Street. When future
development occurs, this would upgrade 23 Avenue to become a major east/west
collector road south of Highway 3. It would help improve the overall flow of traffic for
the area while taking the pressure off of 25 Street and 24 Street leading to the golf
course. A local road should also be developed on the east side of the church
property, to circulate traffic from the north highway commercial area, south to the
23 Avenue main collector. See Figure 3.0, Conceptual Road Network.
8
Amendment 2023
3.5
Stormwater Management
Storm water drainage has been identified as a problem in this area in various storm
water management studies. Presently the NW 10-9-20-W4 is drained over land and
flows from west to east. Storm water run-off also enters the area from land in the
County of Lethbridge, situated to the west, which also must be dealt with. Storm
water management is a major design consideration as historic flood events affecting
Coaldale have been costly for the Town and its citizens. Increased development
activity on the site will have a corresponding impact on surface runoff. Developed
building sites including roof areas, driveways and paved roadways will all speed up
the rate at which storm water will leave individual sites and combine with runoff from
adjacent sites.
This Area Structure Plan will increase the density of the development considerably
from the present, largely undeveloped scenario, and methods must be in place to
deal effectively with the drainage situation. The Stormwater Management Plan is
included under separate cover as Appendix D with a summary in Section 4.2 Storm
Water Management.
3.6
Utilities
A water line off of 30 Street provides water to two existing dwellings, but they have
no sanitary sewer service. The provision and cost of providing municipal services has
been a large obstacle in the development of land in the area in the past. The
provision of treated water service and water lines will also have to be addressed as
well as the provision of sanitary sewers. The town has prepared the Infrastructure
Master Plan to provide overall requirements and context to these deep utilities. The
deep utilities are further discussed in Section 4.4 Utility Servicing and shown in
Figure 4.0, Underground Utilities.
The shallow utility services will all have to undergo major expansions and upgrades
to provide sufficient services to the higher density development. Usually utility
companies require the developers to pay for line relocation, expansion and additional
hookups.
9
Amendment 2023
4.0 DESIGN SCHEME (AMENDED 2023)
The following were design criteria that were used in the development of the new design
scheme.
The 2023 Amendment concept shows one storm water detention pond in the location
where the Waterfront Pond is currently constructed. Additionally the operator of the
existing Westgate Dry Pond will be examined. Changes will be made to the existing
Waterfront Pond as required to meet storage requirements and Town of Coaldale
operational objectives and may include changes to the storage volume, outlet
controls, lining, and or erosion control measures.
The Town of Coaldale has indicated that there is not a requirement for a school in
this area.
Based on the regional pathway requirements as outlined in the Town's MDP, the
Parks and Trails Master Plan, as well as the Recreational Master Plan, a regional
pathway should be provided along 23rd Avenue and adjacent to the storm water
pond. Additional land has been planned for a park on the west side of the storm
pond. The total area for this park and pathway is 0.82 ha (2.03 acres). Any shortfall
in the MR required will be made up with a combination of land and cash-in-lieu to the
Town.
The 2003 ASP included a buffer strip adjacent to the east side of 30th St. to help
handle overland flow from the County. The construction of storm water management
facilities and ditch improvements on the west side of 30th Street has practically
eliminated runoff from the county flowing into the ASP area. The Town has indicated
that a buffer strip is not required adjacent to 30th Street for drainage purposes.
A strip of land adjacent to 30th Street may be required for road right of way. This will
be determined based on the TIA.
No single family lots will front onto 30th Street. No lots will be provided with
vehicular access to 30th Street.
Low density lots in the undeveloped area have been consolidated from the previous
concept plan, into the southern portion of the ASP area. Existing single family is
developed in the southeast corner of the ASP area.
The land uses along the south side of Highway No. 3 have been changed from the
2003 ASP to reflect the current developments.
A multi-family land use is proposed along the south side of 23 Avenue with the
development of semi-detached housing being planned.
A multi-family area has been consolidated along the north side of 23 Avenue to
provide for apartments, row housing and town houses.
10
Amendment 2023
Since 2003 three TIAs have been prepared, with the last one being for the
Southwest Coaldale ASP in 2022 which has yet to be approved by the Town of
Coaldale and Alberta Transportation. The TIAs have made recommendations for the
intersections of:
Highway No. 3 and 30th Street,
Highway No. 3 and Land O' Lakes Drive,
Land O' Lakes Drive and 23rd Avenue.
30th Street and 23rd Avenue.
In the past few years, improvements and signals were installed at the 30th St. and
the Land O' Lakes Drive intersections with Hwy. No. 3. These improvements appear
inadequate and it is recommended that consideration be given to include this
intersection in a new TIA prior to subdivision. See Figure 3.0, Conceptual Road
Network.
4.1
Type Of Development
The predominant land uses for the plan area will be a mix of residential (low density,
multi- family), highway commercial and public/institutional use. Green space will be
provided in conjunction with the Waterfront SWMF, a dedicated park area and
proposed pathways. A PUL site will be designated to accommodate stormwater
management expansion. The land use districts will stipulate and regulate the
minimum parcel sizes, development setbacks, permitted and discretionary uses and
other design standards, which will be applied to this area. See Figure 1.0,
Conceptual Land Use.
4.1.1 Housing Types
The conceptual design illustrates a layout capable of providing for a wide variety of
housing types to cater to all residents. Land ownership patterns, existing land use,
population growth, household composition, service connection availability, interest
rates, employment opportunities and housing trends all influence the type and pace
of residential development. A mixture of residential uses including single family,
semi-detached and multi-family housing will be provided for in this plan. Details of
the proposed land uses and densities are shown in Appendix B Table 1 - Unit Density
and Population Projections for Developed and Undeveloped ASP Sites and Table 2 -
Dwelling Unit Density & Population Projection for Undeveloped Residential Sites.
a)
Multi−family
Multi-family housing will be located along both sides of 23rd Avenue, providing
good access and egress to facilities in Town and to Hwy. 3.
11
Amendment 2023
The multifamily north of 23rd Avenue is shown as three large lots which will be
subdivided based on market demand at the time of development. If market
demand indicates the need for seniors housing the R2 land use district will
allow for this type of residential housing.
Three multifamily sites containing a combined total of 2.53 ha are shown on
the north side of 23rd Avenue. The zoning is proposed as R-2 with a maximum
density of 44 units per ha. This results in about 111 units for these sites.
Town houses, duplexes and four plexes will be developed on these sites.
Two multifamily sites containing a combined total of 0.90 ha will be zoned as
R-2L with a maximum density of 33 units per ha. Semi-detached units are
proposed for these sites.
b)
Single Family
Single family development is proposed south of 23rd Avenue. To provide a
range of housing types the 2023 ASP Amendment proposes a mixture of
larger, medium, and smaller houses.
-
R1A (Area 1, Block 8) density is proposed adjacent to the golf course, and
Westgate Landing as well as along 30th Street. The zoning for these is R-
1A with minimum lot width of 50 feet.
-
Area 1 and 2 in Block 9 are proposed to have a zoning of R-1A*. The
requirements of the R1A zoning will be the same for the R-1A* zoning,
except the minimum allowable width of each lot will be 46 feet.
-
R-1B zoning is proposed for Area 2, Block 8 and Area 1, Block 10. The
minimum width of each lot is 40 feet.
4.1.2 Highway Commercial Development
The Town's Municipal Development Plan and various other municipal documents
identify the importance of providing more commercial land within the Town,
especially highway commercial.
This dedicated area of highway commercial use helps accomplish a number of
overlapping municipal objectives including:
preventing the creation of further residential properties backing on Highway
3, and helping to buffer residential areas proposed for the south,
creating additionally needed commercial areas adjacent to the highway,
help strengthening the Town's visual image along the highway.
Between 2003 and 2023 approximately 3.5 ha (8.6 acres) of Highway Commercial
land have been developed in the ASP area. This includes Home Hardware,
McDonalds, Tim Hortons, and other commercial buildings.
12
Amendment 2023
Additionally, the Church site comprises 1.8 ha (4.5 acres) with approximately the
southern one third being undeveloped.
The remaining land in the ASP area designated for highway commercial that is
underdeveloped is approximately 4.25 ha (10.5 acres) which is the Coaldale nursery
property at the corner of Highway No 3 and 30th Street. With its proposed Highway
Commercial land use, the Coaldale Nurseries can continue to operate at this location
until they decide to relocate. At that time this parcel would be available for future
commercial development.
In regard to development standards for highway commercial development:
The development authority may permit more than one commercial building
on a parcel if it is part of a planned multi-use commercial hub site. The
developer will be responsible for servicing and costs, in conjunction with the
Town of Coaldale and any of the shallow utility companies' requirements,
in regard to servicing such a site.
The Town of Coaldale's Land Use Bylaw setbacks and minimum lot sizes
shall apply as the standards of development. Although an approval and
permit from Alberta Transportation is required for development adjacent to a
highway, Alberta Transportation has indicated that they will normally let the
Town's regular setbacks apply, as stipulated in the Highway Commercial -
HC district of the Land Use Bylaw.
4.1.3 School Site
The 2003 ASP indicates that the public-school authority would like a site set aside for
a new facility for children in kindergarten through grade 4. The town has now
indicated that there is not a need for reserving a site for a school facility.
Accordingly, the 2023 ASP Amendment has not provided a site for a school.
4.1.4 Parks and Open Space
A walkway/ pedestrian pathway is proposed along the North side of 23rd
Avenue. This pathway will extend from 30th Street easterly to the storm pond
and then proceed to the north side of the pond and then easterly to connect
with the sidewalk on Land O Lakes Drive. Landscaping will be installed along
the pathway which will be 3.0m in width.
A park area about 0.6 ha in size, will be developed on the west end if the
storm pond. The pathway will link through the park where it is planned to
have a play area, park benches and landscaping.
Detailed landscape design of the pathway and park will be completed during
the subdivision process.
13
Amendment 2023
The pathway and proposed park have a combined area of 0.78 ha. Any
shortfall from the 10% municipal reserve requirement will be met through
cash-in-lieu to the Town reserve fund.
4.2
Storm Water Management
MGCL has completed a Stormwater Management Plan (SWMP) see Appendix D -
Storm Water Management Plan in support of the ASP Amendment. Several options
and opportunities were explored in collaboration with the Town for the stormwater
management system.
For the ASP Lands, the primary storm water management facilities are the:
Waterfront SWMF,
Westgate Dry Pond
Town of Coaldale storm trunk that parallels Highway #3 and drains east into
the Parkside Acres SWMF, and
Highway #3 ditch.
The following are the proposed stormwater management improvements for the West
Coaldale ASP:
a. New development will be provided with a minor (piped) system to be
designed and constructed to accommodate the runoff from development area
for a 1:5-year 4-hour rainfall event.
b. All commercial and large multifamily development will be required to provide
onsite detention to reduce major event peak flows to the capacity of the
minor system,
c. All streets and lower density residential development will be required to
provide on-street (trapped lows) detention and overland flow on the streets to
manage major event peak flows,
d. 23rd Avenue will be designed as an emergency overland flow route for flows
adjacent to 23rd Avenue, 30th Street and west of 30th Street including
emergency overflow from the Malloy 2 pond.
e. The southwest undeveloped block of land (SWMP Area '4') minor system will
be designed to accommodate 1:5-year 4-hour rainfall event runoff from 30th
Street and the area of Evergreen estates that currently drains through the
southwest undeveloped block of land.
f.
The southwest undeveloped block of land will drain to the Waterfront SWMF.
14
Amendment 2023
g. It is technically feasible to redirect most of the Coaldale Nurseries site (SWMP
Area '7') to the Waterfront SWMF to reduce flows to the Highway #3 ditch.
The costs and funding arrangements of providing stormwater servicing of the
current Coaldale Nurseries site through the southwest undeveloped block of
land will be examined during the detailed design.
h. The Waterfront SWMF will be modified:
With a new outlet control structure or modification of the existing control
structure:
To control the Normal Water Level at 865.66, changed from 866.00 to
reduce the amount of backup into the Watergate Landing storm
system and increase the Waterfront SWMF storage volume.
To an adjustable flow control structure allowing for zero release,
gradual release and up to a full open release of up to 600 lps for rapid
pond draw down when operationally required by the Town. This will
dramatically reduce the downstream peak flows from the ASP Lands
and eliminate any chance that development will make the downstream
situation worse.
i.
With signage be installed at the high-water level to warn and educate the
public on the elevation of expected flooding.
j.
To increase the active volume to 28,387 below a water surface elevation of
868.00 by expanding the pond in the southwest corner.
k. By completing the lining in the Waterfront SWMF, it is noted that the north,
east and south sides are lined.
l.
To have appropriate shoreline erosion protection installed.
4.3
Road Network
4.3.1 Existing Transportation Impact Assessments (TIA)
Since 2003 three TIAs have been prepared, with the last one being for the
Southwest Coaldale ASP in 2023 which has yet to be approved by the Town of
Coaldale and Alberta Transportation. The TIAs have made recommendations for the
intersections of:
Highway No. 3 and 30th Street,
Highway No. 3 and Land O' Lakes Drive,
30th Street and 23rd Avenue.
Land O' Lakes Drive and 21st Avenue.
15
Amendment 2023
In the past few years, improvements and signals were installed at the 30th Street
and the Land O' Lakes Drive intersections with Hwy. No. 3. These improvements
appear inadequate, and a new TIA maybe required to re-visit these intersections and
roadways.
4.3.2 Roadways
The roadway network and classifications are shown conceptually in Figure 3.0,
Conceptual Road Network.
The conceptual roadway network drawing includes the following:
It is proposed to extend 23rd Avenue as a Collector road connecting with 30th
Street.
A regional trail/ pathway is proposed along the north side of 23rd Avenue
extending from 30th Street to a proposed park on the west side of the
Waterfront storm pond and then to Land- O- Lakes Blvd.
The multifamily on the southerly third of the church site will access to Land-
O- Lakes Blvd from existing road right of way along the north boundary of the
Waterfront storm pond.
21st Avenue will extend as a Collector road, westward and then southerly to
connect with 23rd Avenue.
4.3.3 New TIA
The Town of Coaldale is undertaking the preparation of a new TIA for the ASP
site. The new TIA will address roadways and intersections that are affected by
existing and proposed development within the ASP site.
Changes to the conceptual design and layout for the lots, roadways and
intersections in the ASP shall be made and approved by the Town, upon
completion of the new TIA and prior to subdivision.
The traffic and roadway design shall be consistent with existing Town plans,
policies, bylaws and studies including the Town Infrastructure Master Plan,
the Transportation Master Plan and the Parks and Trails Master Plan.
4.4
Utility Servicing
Water and sanitary services to the undeveloped areas within the ASP boundary will
be extended from the existing utilities. The existing water and sanitary services
within the ASP area and the conceptual utility extensions are shown in Figure 4.0,
Underground Utilities.
16
Amendment 2023
A site servicing study will be undertaken at the tentative planning stage. This study
will verify utilities requirements in the ASP area. As well offsite requirements to
service the development area will be assessed. The Town of Coaldale will provide
existing network modeling and offsite requirements for these utilities.
4.4.1 Water Distribution System
The municipal water system has been installed in Land-O-Lakes Boulevard, 21st
Avenue (in front of Tim Horton's, McDonalds, the Church, and Home Hardware), the
east part of 23rd Avenue, the Waterfront and Westgate Landing developments.
Municipal water will be extended along 23rd Avenue to 30th Street to connect with an
existing 350 mm water pipe. Water mains will be looped southerly off of 23rd Avenue
to service the residential area on the south side of 23rd Avenue.
The Coaldale IMP recommends the extension of a 300mm water line along 21st
Avenue, connecting to a 300 mm water line along 21st Avenue, connecting the 300
mm pipe adjacent to the church site with the existing 350 mm water line along 30th
Street. This requirement shall be verified in the Town's modeling of the water
system.
4.4.2 Sanitary Sewer System
The municipal sanitary sewer system has been installed in Land-O-Lakes Boulevard,
21st Avenue (in front of Tim Horton's, McDonalds, the Church, and Home Hardware),
the east part of 23rd Avenue, the Waterfront and Westgate Landing developments.
The current Town of Coaldale sanitary model appears to show that there is adequate
capacity in the existing sanitary system to allow further development in the ASP area
to proceed. This shall be verified by the Town at the tentative planning stage.
Municipal sanitary sewer will be extended from the existing stubbed services in 23rd
Avenue, through the new roads in the development.
4.4.3 Street Lighting
Street lighting will be provided by the developers along the new road network to
current road lighting standards at the time of development.
4.4.4 Shallow Utilities
All shallow utilities (electrical, telephone, gas, cable, etc.) shall be underground. It is
preferred that shallow utilities will be in road rights-of-way, or in utility rights-of-way
adjacent to roads.
The actual shallow utility distribution network and facilities will be determined in
conjunction with the shallow utility service providers at the time of development.
17
Amendment 2023
The developer will contact all shallow utility providers sufficiently in advance of
development to facilitate a coordinated design and installation of all improvements
required by the development. It is expected that shallow utility providers at a
minimum will have provided their preliminary designs and layouts at the time of
submission of detailed design drawings to the Town.
4.4.5 Phasing
The phasing of the development is going to be largely based on market demand.
Currently the first phase of the residential development will be the lots and streets
parallel with and adjacent to the golf course and the easterly north/ south road
connecting with 23 Avenue. The second residential stage will be the lots and
roadways on the north side of Phase 1. The last residential phase will be 23rd Avenue
and the lots abutting 23rd Avenue.
The highway commercial will be developed in accordance with the wishes of the
Coaldale Nurseries. There is not a known time frame for this.
4.5
Neighborhood Comments
4.5.1 Open House, March 2, 2022
The Town conducted an open house that was held on March 21, 2022; an online
survey between March 7, 2022, and March 24, 2022; and in-person meeting held on
March 15 and 16, 2022.
There appeared to be general support in having the ASP approved and to have this
area developed.
The following summarizes concerns and suggestions made during the process of
engaging the public.
Included are the responses as to how these will be handles in the ASP and during the
detailed design.
What We Heard:
Walking paths, playgrounds, additional green space, and landscape enhancements
around the storm pond were requested by numerous respondents.
How We Responded:
The Town of Coaldale Strategic Plan encourages pathways in strategic
locations especially the eastward expansion of a pathway from 30th Street
The ASP includes a pathway that will be developed along 23rd Avenue from
30th Street to the storm pond. The path will then extend along the west and
north side of the pond up to Land O' Lakes Drive.
18
Amendment 2023
A park containing about 0.55ha will be developed on the west side of the
storm pond.
Landscaping in the form of irrigated grass, additional trees, and shrubs will be
provided along the pathway, in the park and around the storm pond. A
playground will be incorporated into the park.
Green space is currently provided within the ASP boundary in the Westgate
Landing development. The Land O' Lakes golf course along the south
boundary of the ASP site provides a very large and visual green space as well
as a recreational facility that benefits not only the neighborhood but also
community of Coaldale.
What We Heard:
It was suggested that there be a green strip or pathway along the west side of the
Westgate subdivision.
How We Responded:
A pathway/ green strip is not planned on the West side of the Westgate Landing
development. This is due to the fact that the pathway would extend to the golf
course boundary where it would have to terminate. This could result in pedestrian
traffic onto the golf course raising a safety concern and interference with the
operation of the golf course. The minimum size of lots along the boundary with
Westgate Landing will be 50 feet thereby reducing the adjacent lot density.
What We Heard:
Concerns were raised with respect to the inclusion of multifamily development in the
ASP.
How We Responded:
The ASP makes provisions for a variety of housing types such as single family,
duplexes, row housing, town houses, and smaller apartments. This is in keeping with
the Town of Coaldale Municipal Development Plan. The Residential Policies section of
the plan speaks to having multifamily development throughout the community and
not segregated to an individual area. Additionally a diversity of dwelling sizes and
dwelling types are encouraged. This variety will enhance the visual aspects of
multifamily housing and will provide housing for a broader range of residents
including, seniors, younger families, professional people and lower income families.
What We Heard:
It was suggested that provisions be made for seniors housing.
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Amendment 2023
How We Responded
The ASP has planned for multifamily housing along the north side of 23rd Avenue
and on the south side of the church property. Additionally semi-detached dwelling
are planned for the south side of 23rd Avenue. If the market conditions indicate a
need for senior's housing, the Town's land use bylaw permits senior's housing on
multifamily sites.
What We Heard:
There were safety concerns expressed with respect to increased traffic on 23rd
Avenue and Land O' Lakes Drive.
How We Responded:
The Town of Coaldale Strategic Plan encourages the use of crosswalks and
pedestrian lights to increase pedestrian safety and minimize conflict with motorized
vehicles. The recommendations and the concerns raised in the Open House will be
addressed during the detailed design of 23rd Avenue. Traffic calming strategies and
other roadway design features such as traffic circles could be incorporated to
increase pedestrian and vehicular safety.
What We Heard:
Numerous concerns were raised with respect to increased noise, dust, and garbage
that could be created by the development.
How We Responded:
Total control of noise, dust & garbage in a construction area is very difficult to
achieve, however steps will be taken to help minimize the impact on the
neighborhood. The town requires that an erosion control plan be submitted for
approval together with the detailed underground & roadway plans.
This plan will detail the mitigation to be provided to help control dust and soil erosion
throughout construction. This would include snow fencing, to reduce the effect of
blowing dust and silt fencing for erosion that may be caused by rainfall. The
developer will also be required to have water trucks used to reduce dust levels.
Additionally the lot surfaces will be graded into small windrows, again to reduce dust.
House builders will be required to have dumpsters available and to keep their lot
clean from garbage during construction.
Conclusion:
There were numerous individual comments and suggestions received during the
neighborhood engagement process. At the ASP stage of planning it isn't possible to
address all of these. Where practical to do so, measures to address these concerns
will be considered during the detailed design stage.
20
Amendment 2023
4.5.2 Open House, February 2023
The Developer conducted an Open House that was held on Wednesday, February 22,
2023. Approximately 150 invite letters were sent to neighbouring property owners.
Additionally an ad was placed om the Sunny South News and a sign advertising the
open house was placed near the storm pond. Approximately 45 people attended the
open house. It appeared that there was fairly strong support for the ASP.
The following summarizes concerns and suggestions received from the public.
What We Heard:
There were five written comments received at the open house. All were in favour of
the ASP and the majority felt that there should be front driveway for the duplexes
along 23rd Avenue and they also felt the lanes were a good idea.
How We Responded:
These comments reflected support for the Developers plan to have front driveways
and a lane for the duplexes along 23 Avenue. No further action is required.
What We Heard:
Several people living in Westgate Landing and backing onto the ASP site felt that
there should be a green strip separating their lots from the ASP site. Additionally
concern was expressed about the poor condition of the fence separating their lots
and the ASP site.
How We Responded:
A pathway/ green strip is not planned on the West side of the Westgate Landing
development. This is due to the fact that the pathway would extend to the golf
course boundary where it would have to terminate. This could result in pedestrian
traffic onto the golf course raising a safety concern and interference with the
operation of the golf course. The minimum size of lots along the boundary with
Westgate Landing will be 50 feet thereby reducing the adjacent lot density.
The replacement of any fence should be the responsibility of the current Westgate lot
owner and/or any future lot owners backing onto their lots. This issue has not been
responded to in the ASP.
What We Heard:
Almost all the attendees were generally in favor of the land being developed and
were in favor of the Area Structure Plan. The following are a reification of some of
the verbal comments received during the Open House. Where possible these will be
addressed during the design phase of the development.
Concern with raised respect to traffic at the intersection of 23 Avenue and
Land O Lakes Drive and with the intersection of Highway 3 and Land O Lakes
Drive.
21
Amendment 2023
Concern was expressed about truck traffic along 23 Avenue during subdivision
and house construction.
Concern was expressed about the lack of landscaping around the storm pond.
Strong support was received for having front driveways and rear lanes as
shown in the ASP Concept Plan. This applied to lots fronting on 23 Avenue
and the lane in the R1A zoned lots.
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Amendment 2023
5.0 OTHER SUBDIVISION AND DEVELOPMENT ISSUES
5.1
Off-site Levies and Development Fees
In order for an orderly, well designed, and adequately serviced subdivision to be
developed, off-site levies will have to be applied to development area over and above
individual on-site servicing and development costs. These levies usually will include
the combined estimate costs of:
sanitary trunk lines,
improvements to the sewage treatment facilities,
water main extensions,
storm water dentition ponds costs,
storm water sewer lines,
collector and service road costs,
design and engineering fees.
In addition, if other services are supplied to develop a subdivision, development
agreements with the municipality should include those other direct costs as well.
The Town of Coaldale has an Off-Site Levy and Development Fees Bylaw that will
apply at the time of subdivision and development.
5.2
Municipal and School Reserve
Municipal and/or school reserve will be provided in accordance with section 666 of
the Municipal Government Act at the time of subdivision.
If a landowner's parcel is not designated for land dedication for a green
space, park or school, municipal and/or school reserve, the landowner will be
required to provide as money in lieu of land.
A compensation plan approved by the Town of Coaldale will compensate any
landowner who is requested to provide for more than 10 percent of their total
land area for parks or schools, for the acreage portion that exceeds their 10
percent dedication.
It is assumed that municipal reserve will be provided as cash in lieu of land
where Highway Commercial subdivisions occur, and the reserve has not been
previously satisfied.
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Amendment 2023
5.3
Architectural Control
Many successful development projects use architectural control, which is a "layer" of
development control that is normally imposed on builders, within a described area, in
order to achieve a uniform standard of development. It is encouraged that the
residential builders, especially on development adjacent to the golf course, and the
existing Westgate development; implement architectural control to create a high
quality, aesthetically pleasing development. However, as this is private land that will
be privately developed, the implementation of the controls will reside with the
developers of the area. If architectural controls are implemented, two important
points to note are:
The desired development standards should be set forth in a document which
is caveated against the land title and remains in effect for a prescribed period
of time.
A level of co-ordination between the developer's architect or design reviewer
and the municipality is also necessary to ensure development and building
permits are not issued if architectural approval has not been given.
Grading elevation for individual lots will be addressed in the Architectural
Controls.
24
Amendment 2023
6.0 SEQUENCE OF DEVELOPMENT OF LAND
Once an Area Structure Plan is in place detailing the density and types of
development allowed, there is a three-stage process to begin developing a parcel of
land.
6.1
Reclassification of Land
6.1.1 Process
Land eligible to be subdivided within the plan area is mainly designated as Urban
Reserve within the Town of Coaldale's Land Use Bylaw No. 677-P-04-13. It will need
to be reclassified to Residential, Residential Multi-family, Highway Commercial or
Institutional/Recreational before subdivision and development can commence.
The process for reclassification as outlined in the Municipal Government Act Revised
Statutes of Alberta 2000 (MGA) provides for advertising of the proposal and holding
a public hearing where affected landowners may comment on the proposal. Council
will make the final decision to redesignate a parcel and there is no appeal of this
decision.
Slight deviations in the proposal in terms of the lot layout may be allowed, provided
they are acceptable to Council. In particular, designs layouts may be altered for the
residential area south of 23 Avenue adjacent to the golf course boundary and for the
seniors housing area designated in the southeast corner, adjacent to 25 Street. If
market or demographic changes occur in the future this area may be designated for
low density residential. However, the overall design scheme including the density,
proposed uses, storm water management areas, road network and utility corridors
should be strictly adhered to.
6.1.2 Policies
1. Proposals for reclassification of lands from Urban Reserve to Residential,
Residential Multi-family, Highway Commercial or Institutional/Recreational
shall follow the process outlined in the Municipal Government Act, Revised
Statutes of Alberta 2000.
2. Only the parcels fronting onto Highway 3 or as indicated in this plan shall be
considered for reclassification to the highway commercial land use district.
3.
The desires of one landowner to subdivide their lands shall not force an
adjacent landowner to do the same if the adjacent landowner is not interested
in development.
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Amendment 2023
6.2
Subdivision and Development of Land
6.2.1 Process
After a parcel of land is redesignated to the appropriate district as outlined in this
plan, the landowner may apply for subdivision of the parcel into separate titles. The
landowner or developer will have certain costs to consider associated with the
subdivision process. These include:
1. Subdivision application fees, survey costs and registration costs.
2. Provision of municipal reserve by way of land or cash in lieu of land in an
amount not exceeding 10 percent of the acreage of the parcel being
subdivided or 10 percent of the per acre value of the parcel being subdivided.
It is assumed that municipal reserve will be provided as either in land, where
it is warranted, or as cash in lieu of land where no park space is to occur.
3. Developers will be required to enter into a Development Agreement with the
Town of Coaldale in regard to providing infrastructure to service the plan area.
4. Developers will be required to provide the following infrastructure to the
Town's specifications to adequately service the area:
water mains and service connections,
sanitary sewer mains and service connections,
storm sewer mains and service connections,
overland drainage system,
paved roadways complete with curb and gutter,
sidewalks and lanes where required,
natural gas (ATCO Gas),
electrical and street lighting (Aquila Networks Canada),
telephone (Telus),
cable television (Shaw Cable).
5. Town off-site levies and development fees (that also helps cover costs for
Town engineering and planning costs associated with the preparation of this
Area Structure Plan) will be applied to developers of the area at the time of
development.
6.2.2 Policies
1. This Area Structure Plan is to be used as a guideline for subdivision when the
landowners decide that they want to subdivide their existing titles.
2. As a condition of subdivision approval, the developer must provide a plan of
survey from a certified Alberta Land Surveyor that certifies the location and
dimensions of any existing buildings and the exact dimensions of the lot to be
subdivided.
26
Amendment 2023
3. Subdivision proposals will be reviewed in terms of conformity to the Area
Structure Plan design scheme. Prior to the application or survey of the
subdivision proposal, developers are encouraged to consult with the Town of
Coaldale and their planning advisor to determine if the proposal is in
compliance with the plan.
4. As a condition of subdivision approval, the landowner or developer shall enter
into a development agreement within the Town of Coaldale.
5. At the time of subdivision, the subdivision authority shall require a landowner
to provide the 10 percent reserve requirement by providing land, paying
money in lieu, or a combination of both.
6. Costs of infrastructure construction shall be borne by the persons owning and
developing land in the plan area.
7. The design of utility infrastructure shall be to the Town of Coaldale and utility
company standards and the Town will provide detailed engineering standards
for the roadways and servicing to the developer at the time of development.
8. Any costs associated with topographic survey or engineering work that may
be required for the subdivision shall be at the expense of the developer.
9. Any utility easement(s) as required by utility companies or the Town of
Coaldale shall be established prior to finalization of the subdivision
application.
10. Lot sizes and layouts shall conform to the standards as described in this plan,
however, in all instances the minimum lot size of the corresponding land use
district in the Town of Coaldale's Land Use Bylaw shall be adhered to when
subdividing a lot.
11. Any proposed deviations in the lot layout, road or designated land uses if
minor in nature may not require an amendment to the ASP provided; they are
acceptable to the Town's administration. However, the overall lot and road
layout, design pattern and density shall be strictly adhered to the satisfaction
of the Town.
12. In respect of market demands and future growth, subdivision may occur in
phases, having regard to the overall design and road layout and servicing
requirements. Any phasing of development shall be reflected by a proposal or
plan that must be approved by the Town of Coaldale.
13. The Town of Coaldale will agree to a formula for the distribution of the costs
associated with the development of the storm water management system for
the area. A landowner, whose parcel of land is not specifically designated to
accommodate the storm water detention as per the design of this plan, will
likely be required to provide money in lieu based on the formula, to pay for
their land parcel share.
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Amendment 2023
6.3
Development of Individual Lots
6.3.1 Process
Once the plan area has been subdivided, the necessary infrastructure in place,
conditions met and separate titles issued, the landowner can apply to the Town of
Coaldale for a development permit to develop a permitted or discretionary use as
listed in the appropriate district (residential, highway commercial, public and
institutional, etc.) allowed for in this plan area and contained in the Town of
Coaldale's Land Use Bylaw.
The landowner will be required to submit an application form, a fee, a site plan
showing the location of the building on the lot, building plans and a grading plan in
keeping with the overall conceptual grading plan for the plan area as contained in
Appendix 2. In addition, the landowner should be aware of the location of any
underground services present before any excavation work is commenced.
The development approval process will include the following:
1. The landowner will be required to submit an application form approval as
required under any architectural control, a fee, a site plan showing the
location of the building on the lot, building plans and a grading plan in
keeping with the overall conceptual grading plan for the plan area as
contained in Appendix 2.
2. Once the application, applicable fee and any required information have been
submitted, the designated officer or the development authority will review and
make a decision on the application. If a proposed development conforms to
this plan and the Land Use By law, the designated officer shall issue a
development permit with or without conditions. If the application is for a
development permit for a discretionary use the designated officer shall send
the application to the development authority for a decision. In this instance,
the development authority shall notify persons likely to be affected by the
issuing of the development permit.
3. The development authority may require that as a condition of issuing a
development permit, the applicant enter into a development agreement with
the Town of Coaldale in regard to the provision of infrastructure services or
pay for an off-site levy.
4. The landowner should be aware of the location of any underground services
present before any excavation work is commenced. In addition, the person to
whom a development permit has been issued shall notify the designated
officer following the stake out of the site but prior to the commencement of
construction.
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Amendment 2023
5. The applicant must commence the development within 12 months from the
date of issuance of the permit, unless the development permit is suspended
or cancelled; otherwise, the permit is no longer valid.
6.3.2 Policies
1. This Area Structure Plan is to be used as a guideline for development in
conjunction with the Land Use Bylaw when considering a development
permit application.
2. All residential, institutional or commercial buildings shall be required to
connect to both the municipal water supply and sewage systems.
3. The landowner/developer will be required to submit an application form, a
fee, a site plan showing the location of the building on the lot, building
plans and a grading plan.
4. Any costs associated with topographic survey or engineering work that may
be required shall be at the expense of the developer.
5. Landowners will be required to provide for adequate storm water drainage
management as created by their land parcel and proposed development.
6. Legal access and egress from a lot shall be indicated on a site plan and
shall be at a location to the satisfaction of the designated officer or the
development authority.
7. On highway commercial designated lands, the development authority may
permit more than one commercial building on a parcel if it is part of a
planned multi-use commercial hub site.
8. In highway commercial areas, sites for outdoor storage of goods, at the
discretion of the development authority, may be permitted if kept in a
neat and orderly manner and/or suitably enclosed by a fence, wall, or
screened with landscaping to the satisfaction of the development authority.
9. In highway commercial areas, the developer will be required to provide to the
satisfaction of the designated officer or the development authority,
landscaping and screening for buffering to adjacent residential streets.
10. Landscaping shall be provided on all street frontages and shall be to the
satisfaction of the designated officer or the development authority.
11. The development authority may require the developer to provide additional
standards of development (parking, landscaping, screening of storage/goods,
etc) in conjunction with Schedules 4, 5, 11 and 12 of the Land Use Bylaw.
SI
SIGN
Appendix A- FIGURES
FIGURE 1 - EXISTING LAND USE
FIGURE 2 - PROPOSED LAND USE
FIGURE 3 - CONCEPTUAL ROAD NETWORK
FIGURE 4 - UNDERGROUND UTILITIES
Tim
Hortons
McDonald's
CHURCH
Home
Hardware
Waterfront
SWMF
Westgate Dry Pond
255-31st Street North Lethbridge, Alberta T1H 3Z4
Ph: (403) 329-0050 E-mail: [email protected] Fax: (403) 329-6594
Consulting Engineers, Planners, and Land Surveyors
EXISTING LAND USE
FIGURE 1.0
Jan 16, 2023
AREA STRUCTURE PLAN
West Coaldale
229648CE
URBAN RESERVE (UR)
Highway 3
24 St
Westgate Dr
Westgate Dr
Westgate Cres
Westgate Cres
Land O' Lakes Dr
Land O' Lakes Dr
24 Ave
25 Ave
23 Ave
22 Ave
21A Ave
25 St
21 Ave
21 Ave
Waterfront
Landing
Waterfront
Landing
24 St
23 Ave
23 Ave
30 St
30 St
30 St
Crowsnest Highway
INSTITUTIONAL / RECREATIONAL (I/R)
UTILITY (U)
RESIDENTIAL STARTER LOTS (R-1C)
RESIDENTIAL (R-1A)
HIGHWAY COMMERCIAL (C-2)
17.65
2.69
1.77
1.28
6.69
3.41
ha
LEGEND
ASP BOUNDARY (Area=39.52 ha)
CURRENT DEVELOPMENT
BOUNDARY
AREA (ha)
ac
43.60
6.64
4.37
3.17
16.54
8.43
SMALL LOT RESIDENTIAL (R-1B)
0.98
2.42
ROADWAYS & LANES
22.71
56.10
EXISTING LAND USE
TOTAL ASP AREA:
39.53
97.67
Tim
Hortons
McDonald's
CHURCH
Home
Hardware
Waterfront
SWMF
Westgate Dry Pond
255-31st Street North Lethbridge, Alberta T1H 3Z4
Ph: (403) 329-0050 E-mail: [email protected] Fax: (403) 329-6594
Consulting Engineers, Planners, and Land Surveyors
PROPOSED LAND USE
FIGURE 2.0
Jan 16, 2023
AREA STRUCTURE PLAN
West Coaldale
229648CE
LEGEND
ASP BOUNDARY (Area=39.53 ha)
Highway 3
24 St
Westgate Dr
Westgate Dr
Westgate Cres
Westgate Cres
Land O' Lakes Dr
Land O' Lakes Dr
24 Ave
25 Ave
23 Ave
22 Ave
21A Ave
25 St
21 Ave
21 Ave
Waterfront
Landing
Waterfront
Landing
24 St
23 Ave
23 Ave
30 St
30 St
30 St
Crowsnest Highway
CURRENT DEVELOPMENT
BOUNDARY
ha
AREA
ac
8.55
4.61
23.47
18.85
4.52
6.25
INSTITUTIONAL / RECREATIONAL (I/R)
UTILITY (U)
SMALL LOT RESIDENTIAL (R-1B)
RESIDENTIAL (R-1A)
HIGHWAY COMMERCIAL (C-2)
3.46
1.86
2.53
9.50
7.63
PROPOSED LAND USE
RESIDENTIAL MULTI-UNIT (R-2)
1.83
INDICATES AREAS THAT WILL REQUIRE A
CHANGE IN LAND USE
3.17
RESIDENTIAL STARTER LOTS (R-1C)
1.28
ROADWAYS & LANES
8.28
20.45
TOTAL ASP AREA:
39.53
97.67
NOTE:
R-1A* INDICATES LOTS WITH A
MINIMUM WIDTH OF 14.02m (46ft)
5.58
RESIDENTIAL (R-1A*)
2.26
2.22
RESIDENTIAL MULTI-UNIT LIMITED (R-2L)0.90
R-1A
R-1A*
R-1A*
R-1B
R-1A
R-1A
R-1B
R-2L
R-2
R-2
I/R
I/R
C-2
C-2
R-2L
I/R
C-2
U
R-1B
Area 1
Blk 9
Area 2
Blk 9
Area 1
Blk 8
Area 1
Blk 8
Area 1
Blk 8
Area 1
Blk 10
Area 3
Blk 10
Area 3
Blk 8
Area 2
Blk 8
Area 1
Blk 11
Area 2
Blk 11
Area 8
Blk 5
Area 7
Blk 5
Area 2
Blk 10
255-31st Street North Lethbridge, Alberta T1H 3Z4
Ph: (403) 329-0050 E-mail: [email protected] Fax: (403) 329-6594
Consulting Engineers, Planners, and Land Surveyors
CONCEPTUAL ROAD NETWORK
FIGURE 3.0
Jan 16, 2023
AREA STRUCTURE PLAN
West Coaldale
229648CE
Highway 3
24 St
Westgate Dr
Westgate Dr
Westgate Cres
Westgate Cres
Land O' Lakes Dr
Land O' Lakes Dr
24 Ave
25 Ave
23 Ave
22 Ave
21A Ave
21A Ave
25 St
21 Ave
21 Ave
Waterfront
Landing
Waterfront
Landing
ASP BOUNDARY
DIVIDED HIGHWAY
COLLECTOR ROAD
LOCAL ROAD
24 St
23 Ave
23 Ave
30 St
30 St
30 St
Crowsnest Highway
NEW DEVELOPMENT
LEGEND
255-31st Street North Lethbridge, Alberta T1H 3Z4
Ph: (403) 329-0050 E-mail: [email protected] Fax: (403) 329-6594
Consulting Engineers, Planners, and Land Surveyors
UNDERGROUND UTILITIES
FIGURE 4.0
Jan 16, 2023
AREA STRUCTURE PLAN
West Coaldale
229648CE
Highway 3
24 St
Westgate Dr
Westgate Dr
Westgate Cres
Westgate Cres
Land O' Lakes Dr
Land O' Lakes Dr
24 Ave
25 Ave
23 Ave
22 Ave
21A Ave
21A Ave
25 St
21 Ave
21 Ave
Waterfront
Landing
Waterfront
Landing
24 St
23 Ave
23 Ave
30 St
30 St
30 St
Crowsnest Highway
LEGEND
ASP BOUNDARY
STORM MANHOLE AND PIPE
NEW DEVELOPMENT
SANITARY MANHOLE AND PIPE
WATER PIPE
EXISTING UTILITIES
FIRE HYDRANT
STORM MANHOLE AND PIPE
SANITARY MANHOLE AND PIPE
WATER PIPE
FUTURE UTILITIES
FIRE HYDRANT
WATER VALVE
FH
FH
FH
FH
FH
FH
FH
FH
FH
FH
FH
FH
FH
FH
FH
FH
FH
FH
FH
FH
FH
FH
FH
FH
FH
FH
FH
FH
Appendix B -Tables
TABLE SHOWING EXISTING AND PROPOSED DENSITIES
TABLE 1
Unit Density & Population Projections
For Developed and Undeveloped ASP Sites
Land Use
Area ha
Units/ha
Number
of Units
People
per unit
Population
R1A/ R1A*
11.76
12.2
143
3.0
429
R1B
2.53
19.0
48
3.0
144
R1C
1.28
23.4
30
2.6
78
R2
1.83
44
80
2.6
208
R2L
0.90
33
30
2.6
78
Roads & Lanes
8.28
----
----
----
----
Highway Commercial
7.63
----
----
----
----
Institutional / Recreation
3.46
----
----
----
----
Utility
1.77
----
----
----
----
TOTAL:
39.53 ha
8.37
331 units
2.83
937 people
TABLE 2
Dwelling Unit Density & Population Projection
For Undeveloped Residential Sites
Block
Zoning
Area ha
Units
per ha
Number
of Units
People
per unit
Population
Area 1, Block 8,
R-1A
2.80
15
42
3.0
126
Area 2, Block 8,
R-1B
0.75
13.3
10
3.0
30
Area 3, Block 8,
R-2L
0.33
24.2
8
2.6
21
Area 1, Block 9,
R-1A
1.13
19.5
22
3.0
66
Area 2, Block 9,
R-1A
1.13
19.5
22
3.0
66
Area 1, Block 10,
R-1B
0.55
23.6
13
3.0
39
Area 2, Block 10,
R-1B
0.25
20.0
5
3.0
15
Area 3, Block 10,
R-2L
0.57
31.6
18
2.6
47
Area 1, Block 11,
R2
1.06
44
46
2.6
120
Area 7, Block 5,
R2
0.77
44
34
2.6
88
TOTAL:
9.34 ha
23.55 units/ ha
220 units
2. 18
618 people
Appendix C - STORMWATER MANAGEMENT PLAN
STORMWATER MANAGEMENT PLAN
Stormwater Management Plan
for
West Coaldale Area Structure Plan
2022 Amendment
NW ¼ Sec 10-9-20-W4M
Prepared for:
Domenic Land Development Corp.
File Number:
229648CE
Dated: February 16 , 2023
CONSULTING ENGINEERS, PLANNERS & LAND SURVEYORS
255 - 31st Street North, Lethbridge, Alberta, T1H 3Z4
PH: (403) 329-0050 FAX: (403) 329-6594
Email: [email protected]
February 16, 2023,
File: 229648CE
Domenic Land Development Corp.
Re:
Stormwater Management Plan
West Coaldale ASP Amendment
We are pleased to submit the Stormwater Management Plan for the West Coaldale ASP
Amendment, final report. This report examines the stormwater management requirements to
develop the Subject Property from its current undeveloped state to residential property.
We trust that this report meets with your needs.
Yours truly,
MARTIN GEOMATIC CONSULTANTS LTD.
James Johansen, P.Eng.
Enclosure
CONSULTING ENGINEERS, PLANNERS & LAND SURVEYORS
255 - 31st Street North, Lethbridge, Alberta, T1H 3Z4
PH: (403) 329-0050 FAX: (403) 329-6594
Email: [email protected]
CORPORATE AUTHORIZATION
This report has been prepared by Martin Geomatic Consultants Ltd. (MGCL) under the authorization of
Domenic Construction Ltd. The material in this report represents the best Judgement of MGCL given the
available information. Any use that a third party makes of this report, or reliance on or decisions made
base upon it is the responsibility of the third party. MGCL accepts no responsibility for damages, if any,
suffered by a third party, as a result of decisions made, or actions taken based upon this report.
Should any questions arise regarding the content of this report, please contact the undersigned.
Revision
Date
Notes
1
July 7, 2022
Initial Report
2
August 19, 2022
Incorporating Towns Comments on the July 7, 2022 report.
3
December 6, 2022
Report changed to reflect a selected set of options and incorporate
Town's comments on the August 19, 2022 report
4
December 9, 2022
Incorporating Town's Comments on the December 6, 2022 report.
5
December 19, 2022
Correcting errors in numbers in the report and making some
changes to improve clarity.
6
February 16, 2023
Changes made to reflect Town comments and make some
clarifications.
MARTIN GEOMATIC CONSULTANTS LTD.
Professional Stamp
James Johansen, P.Eng.
SIGN
SIGN
Stormwater Management Plan for
West Coaldale ASP Amendment
NW ¼ Sec 10-9-20-W4M
C:\Users\Public\Documents\229648 Domenic Land- West Coaldale Subdiv\CE\Reports\Stormwater
Management Plan - West Coaldale Subdivision Feb 14 2023.docx
Contents
1.
Background .......................................................................................................................................... 1
1.1.
The ASP Area ............................................................................................................................... 1
1.2.
Previous Studies and Documents ................................................................................................. 1
1.2.1
Coaldale Stormwater Investigation, UMA, February 22, 2005 .................................................. 2
1.2.2
Malloy Drain Master Drainage Plan and Subsequent Implementation Plans and Studies. ...... 2
1.2.3
Infrastructure Master Plan (IMP) ............................................................................................... 3
1.2.4
Waterfront Development, Record Drawings ............................................................................. 3
1.2.5
Westgate Landing Residential Subdivision, MGCL, October 24, 2011 .................................... 3
1.3.
Current Status of the Stormwater Management System .............................................................. 4
1.4.
Stormwater Management Issues .................................................................................................. 4
1.4.1
Waterfront SWMF...................................................................................................................... 5
1.4.2
Waterfront SWMF Spill Elevation .............................................................................................. 5
1.4.3
Land-O-Lakes Drive, Catchbasins and Overland Flow ............................................................. 5
1.4.4
21st Avenue, Catchbasins and Overland Flow .......................................................................... 5
1.4.5
Home Hardware, Onsite Stormwater Management .................................................................. 5
1.4.6
23rd Avenue Spill Elevation and Low Point ............................................................................... 6
1.4.7
Westgate Drive, Catchbasins .................................................................................................... 6
1.5.
Goals of the Stormwater Management System ............................................................................ 6
2.
Site Analylsis ........................................................................................................................................ 7
2.1.
Existing Storm Improvements ....................................................................................................... 7
2.1.1
Existing Westgate SWMF ......................................................................................................... 7
2.1.2
Existing Waterfront SWMF ........................................................................................................ 8
2.1.1
Existing Highway #3 South Ditch .............................................................................................. 9
3.
Modeling ............................................................................................................................................... 9
3.1.
Design Storms ............................................................................................................................... 9
3.2.
Sub-catchments .......................................................................................................................... 10
3.3.
Model Setup ................................................................................................................................ 10
3.3.1
Changes Made from Predevelopment to Post-development Interim Model ........................... 11
3.3.2
Post-development Model Full Build Out .................................................................................. 12
3.4.
Model Results.............................................................................................................................. 12
3.4.1
Predevelopment Sub-catchments ........................................................................................... 12
3.4.2
Post-Development Sub-catchments........................................................................................ 13
3.4.1
Models Results - Outlets ........................................................................................................ 15
4.
Proposed Stormwater Management System .................................................................................. 20
4.1.
Offsite Stormwater Management System Improvements ........................................................... 20
4.2.
Area 4 .......................................................................................................................................... 20
4.3.
Waterfront SWMF ....................................................................................................................... 21
4.4.
Area 7 .......................................................................................................................................... 22
4.5.
General Layout of the Proposed Stormwater Management System .......................................... 22
4.5.1
Minor System & Waterfront SWMF ......................................................................................... 22
4.5.2
Major System .......................................................................................................................... 22
4.5.3
Emergency System ................................................................................................................. 22
4.5.4
Wet Pond Make-up Water ....................................................................................................... 23
4.6.
How the Proposed Stormwater Management System Addresses Issues .................................. 23
4.6.1
Waterfront SWMF.................................................................................................................... 23
4.6.2
Waterfront SWMF Spill Elevation ............................................................................................ 23
4.6.3
Land-O-Lakes Drive, Catchbasins and Overland Flow ........................................................... 23
Stormwater Management Plan for
West Coaldale ASP Amendment
NW ¼ Sec 10-9-20-W4M
C:\Users\Public\Documents\229648 Domenic Land- West Coaldale Subdiv\CE\Reports\Stormwater
Management Plan - West Coaldale Subdivision Feb 14 2023.docx
4.6.4
21st Avenue, Catchbasins and Overland Flow ........................................................................ 23
4.6.5
Home Hardware, Onsite Stormwater Management ................................................................ 23
4.6.6
23rd Avenue Spill Elevation and Low Point ............................................................................. 24
4.6.7
Westgate Drive, Catchbasins .................................................................................................. 24
5.
Phasing and Triggers for New Stormwater Infrastructure ............................................................ 24
5.1.
Area4 (Subject Property) ............................................................................................................. 24
5.2.
Future Commercial (Area 7) ........................................................................................................ 24
6.
Recomendations ................................................................................................................................ 24
List of Figures
Figure 1 - 2022 ASP Amendment Proposed Land Use Map ..................................................................... 26
Figure 2 - IMP Catchment Areas ................................................................................................................ 26
Figure 3 - Existing Stormwater Drainage Conditions ................................................................................. 26
Figure 4 - PCSWMM Model Setup - Pre-Development .............................................................................. 26
Figure 5 - PCSWMM Model Setup - Post Development - Interim............................................................... 26
Figure 6 - PCSWMM Model Setup - Post Development - Full Build Out ................................................... 26
Figure 7 - Pre-development Offsite Inflows and Outflows .......................................................................... 26
Figure 8 - Parkside Trunk Outlet Hydrograph ............................................................................................. 26
Figure 9 - Highway 3 Outlet Hydrograph .................................................................................................... 26
Figure 10 - Proposed SWMP Offsite Inflows and Outflows ........................................................................ 26
Figure 11 - Waterfront SWMF Conceptual Design ..................................................................................... 26
Figure 12 - Stormwater Minor System Plan ............................................................................................... 26
Figure 13 - Stormwater Major System Plan ............................................................................................... 26
Figure 14 - Stormwater Emergency Storage and Overland Drainage Plan ............................................... 26
List of Tables
Table 1 - Westgate Landing Storage Requirements
3
Table 2 - Storage Provided for Westgate Development
4
Table 3 - Existing Westgate SWMF Stage Storage
7
Table 4 - Existing Waterfront SWMF Stage Storage
8
Table 5 - Existing Highway #3 South Ditch Stage Storage
9
Table 6 - Design Storms
9
Table 7 - Proposed Preliminary Design of Waterfront SWMF
11
Table 8 - Pre-Development - Model Results Sub-catchments
13
Table 9 - Post-Development - Model Results - Sub-catchments
14
Table 10 - Post Development - Model Results - Sub-catchments with Area7 Draining to the Waterfront
SWMF
15
Table 11 -Model Results - Outlets
16
Table 12 - Waterfront SWMF Design
18
Table 13 - Waterfront SWMF Modeled Performance
19
Stormwater Management Plan for
Page 1 of 25
West Coaldale ASP Amendment
NW ¼ Sec 10-9-20-W4M
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1.
BACKGROUND
Martin Geomatic Consultants Ltd. (MGCL) was retained by Domenic Construction Ltd to prepare a
Stormwater Management Plan (SWMP) for the West Coaldale ASP 2022 Amendment.
The purpose of the SWMP is to:
Layout a plan of how the runoff from the ASP lands and upstream will be managed and disposed of,
Propose a general plan for infrastructure improvements required to support further development of
the ASP lands.
Determine the storage requirements for the Waterfront SWMF to meet the requirement of zero
release during a storm event.
The SWMP has been prepared following the guidance of:
Town of Coaldale Storm Bylaw 764-R-07-19
Water Act Approval / 00383892-00-00 and the corresponding Malloy Drain Master Drainage Plan
(MPE 2010)
Town of Coaldale Design Standards, which are currently understood to be:
o
City of Lethbridge Design Standards,
o
Alberta Environment and Parks, Standards and Guidelines for Municipal Water Works,
Wastewater and Storm Drainage Systems,
Coaldale Infrastructure Master Plan, Dec 2019 MPE Eng. Ltd.
West Coaldale ASP, 2022 Amendment (not approved by the Town at the time of writing this report).
1.1. The ASP Area
Approximately half of the ASP lands have been developed as highway commercial, a church and
single-family residential. The boundaries of the ASP lands are shown on Figure 1 and are generally
described as:
North Boundary - Highway #3,
West boundary - 30th Street,
South boundary - Land-O-Lakes Golf course, and
East Boundary 24th / 25th Street.
Figure 1 also shows the proposed land uses for the West Coaldale ASP 2022 Amendment.
1.2. Previous Studies and Documents
Stormwater planning for the Town of Coaldale is guided by:
Malloy Drain Master Drainage Plan, MPE, March 2010 (MDMDP),
Town of Coaldale, Infrastructure Master Plan, December 15, 2019 (TCIMP),
Malloy Drain Phase 2 Preliminary Engineering Report, September 30, 2015,
Previous reports relevant to the existing Waterfront Storm Pond that have been examined are:
Coaldale Stormwater Investigation, UMA, February 22, 2005,
Waterfront Development, Record Drawings, UMA, April 23, 2008
Westgate Landing Residential Subdivision-Stormwater Management Plan, MGCL, October 24,
2011
Stormwater Management Plan for
Page 2 of 25
West Coaldale ASP Amendment
NW ¼ Sec 10-9-20-W4M
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Westgate Landing, Record Drawings, MGCL, December 15, 2013
The existing Waterfront SWMF has gone through several incarnations which are briefly summarized
below:
1.2.1 Coaldale Stormwater Investigation, UMA, February 22, 2005
This report identified the need for a storm pond at the current location of the Waterfront SWMF.
The report stated the Coaldale, Master Stormwater Management Plan, identified the maximum
release rate from the 940-ha catchment area as 1.0 m3/s which calculates to an allowable
release rate of 1.064 lps/ha. The 40-ha proposed development share of the 1.0 m3/s would be
42.6 lps. A total of 158,00 m3 of storage would be required to attenuate the peak flow from the
940-ha to 1.0 m3/s. It further identifies that 85,000 m3 of storage would be stored in the 40-ha
proposed for development. It does not identify where the remainder of the storage would be
provided however it is assumed that it was intended to be provided upstream of the 40-ha
proposed development.
The report identifies that an interim pond is proposed for Phase 1 with:
A permanent water level of 866.0 metres
A high-water level of 868.0 metres
Top of berm of 868.6 metres giving a freeboard of 0.6 metres, and
An active volume of 24,400 m3.
The remaining 60,600 m3 of active storage would be provided in subsequent phases. It is
noted that the 1.0 m3/s release rate was for the whole 940-ha catchment area and that plans
have change over time and reduced the catchment area of the Waterfront SWMF to under 39.0
ha.
1.2.2 Malloy Drain Master Drainage Plan and Subsequent Implementation Plans and
Studies.
The Malloy Drain Master Drainage Plan identifies the offsite sub-catchment as COAL-2 with a
catchment area of 522 ha. vs. the UMA reports 900 ha. The Malloy Drain Master Drainage
Plan makes the following recommendation with respect to new development greater than three
residences:
Interim Policies:
Zero discharge allowed during storm event. Release to be allowed only after a storm
event and upon approval by Drainage authority.
Maximum allowable post-event discharge rate equivalent to 0.4 lps/ha
Inclusion of the upstream contributing areas in stormwater management plans.
After the Malloy Drain Master Drainage Plan, the Malloy 2A Project was undertaken as
recommended in the Malloy Drain Master Drainage Plan and diverted bulk of the offsite sub-
catchment COAL-2 north across Highway #3 with a small area of 30th Street that drains through
the Subject Property.
Stormwater Management Plan for
Page 3 of 25
West Coaldale ASP Amendment
NW ¼ Sec 10-9-20-W4M
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1.2.3 Infrastructure Master Plan (IMP)
Figure 2 presents the IMP catchment areas for the ASP Lands. Catchment F drains to the
Waterfront SWMF and catchment M (approximately 60 metres of the commercial land on the
north edge of the ASP Lands) draining north to the Highway #3 ditch.
The IMP Catchment F is not consistent with currently constructed infrastructure. Of the 35.0-ha
shown draining to the Waterfront SWMF 2.9-ha drains directly east to the Parkside Trunk and
3.3 ha of developed area and 4.2 ha of developed area drains north to the Highway #3 ditch.
0.31-ha north of and including parts of 21st Avenue drains by pipe to the Waterfront SWMF and
not to the Highway #3 ditch as shown in the IMP. There are several areas that drain through a
pipe system to the Waterfront SWMF, but overland flow is away from the Waterfront SWMF.
The IMP indicates the Waterfront SWMF is a Dry Pond with a current volume of 32,500 m3.
Review of the IMP input and output files shows that the Waterfront SWMF was modeled as a
cylindrical structure with a constant area of 6914.9 m2 from pond bottom elevation of 864.00 to
a maximum water elevation of 867.67, which calculates as 32,500 m3 of storage volume. The
Waterfront SWMF is a Wet Pond and does not have a uniform cross-section, see Table 4. With
a pond bottom elevation of 864.00, NWL of 866.00 the initial depth should have been 2.0m. If
the IMP model had set the Waterfront SWMF up as a wet pond with the same cross-sectional
area it would have only provided 18,670 m3 of active storage. The IMP estimates the total
1:100-year run off volume from Catchment F at 27,000 m3.
1.2.4 Waterfront Development, Record Drawings
The Waterfront Record Drawings show the commercial property east of Land-O-Lakes Drive
and the majority of Land-O-Lakes Drive north of the Waterfront SWMF draining north to the
catchbasins located in 21st Avenue immediately east of Land-O-Lakes Drive.
1.2.5 Westgate Landing Residential Subdivision, MGCL, October 24, 2011
Table 1 lays out what the Westgate Landing Residential Subdivision stormwater management
report identified as the storage requirements for the Westgate development.
Table 1 - Westgate Landing Storage Requirements
Required
Storage
Phase 1 Pond Active storage volume to HWL (868.00)
8,500 m3
Town's excess storage requirements (Phase 2)
12,000 m3
Town's MR land Exchange (Phase 2)
5,000 m3
Phase 2 required stormwater storage
6,800 m3
Total Active Storage Required
32,240 m3
The report does not provide an explanation for the Town's storage requirements. The report
states that an expansion of the Waterfront Pond was required to meet the Town's storage
requirement of 32,240 m3.
Table 2 lays out the storage to be provided in the proposed plan. The storage requirement
would be meet by the volume available below an elevation of 868.67 metres, made up of
Stormwater Management Plan for
Page 4 of 25
West Coaldale ASP Amendment
NW ¼ Sec 10-9-20-W4M
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storage in the Waterfront SWMF, Westgate SWMF (dry pond), pipe storage and trapped lows in
the streets and was estimated to be 32,847 m3.
Table 2 - Storage Provided for Westgate Development
Phase 1
Pond
Phase 2 Pond
(Westgate Expansion)
Permanent Storage (NWL 866.00)
13,000
15,200
Active Storage (HWL 868.00)
18,300
21,042
Storage Available Above HWL to 868.67
Waterfront SWMF
8,818
Westgate Dry Pond
1,911
Trapped Low Storage on 23rd Avenue and in
Westgate
920
Pipe Storage (Volume stored in stormwater
collection system)
156
Total Active Storage from HWL to 868.67
11,805
Total Active Storage Available to 868.67
18,300
32,847
Total Storage to 868.67
32,300
48,047
1.3. Current Status of the Stormwater Management System
Figure 3 presents the current drainage situation for the ASP lands. Currently there are three
discharge points for the ASP lands:
An existing storm trunk that roughly parallels Highway #3 and drains east into the Parkside
SWMF and is identified in this SWMP as the "Parkside Trunk".
The south ditch of Highway #3 which drains north across Highway #3 to the Birds of Prey
wetland,
An emergency overflow on Land-O-Lakes Drive that drains east to 24th Street and from there
east on 23rd Avenue.
The central feature of stormwater management in the ASP lands is a stormwater management facility
constructed as a wet pond in the approximate center of the ASP area and known as the Waterfront
SWMF. The Waterfront SWMF drains east and then north to the Parkside Trunk.
The undeveloped Area4 currently drains into the Waterfront SWMF. The Waterfront SWMF drains
through a storm trunk that goes east from the Waterfront SWMF in 23rd Avenue and continues in
Waterfront Landing (entrance road extension of 23rd Avenue) from which it goes north to the Parkside
Trunk, which is located immediately south of, and parallels Highway #3, draining to the east.
The undeveloped Area7 currently drains into the Highway #3 ditch.
1.4. Stormwater Management Issues
There are several points of concern in the Waterfront SWMF catchment area. These are described in
more detail below.
Stormwater Management Plan for
Page 5 of 25
West Coaldale ASP Amendment
NW ¼ Sec 10-9-20-W4M
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1.4.1 Waterfront SWMF
The existing Waterfront SWMF was originally constructed without a liner. The 2012 expansion
lined the north, east and south sides of the pond. The west side of the pond was not lined as it
was expected that the pond would need to be expanded to the west.
The orifice plate installed in the outlet manhole has diameter of approximately 0.6 metres and
does not provide any meaningful flow control from the Waterfront SWMF. This means that the
Waterfront SWMF is not serving its intended function of reducing the peak flow into the
downstream stormwater management system. Because of this, water level fluctuations from
runoff in the Waterfront SWMF likely have been minimal.
1.4.2 Waterfront SWMF Spill Elevation
The Waterfront SWMF spills to 23rd Avenue at a spill elevation of 868.67. 23rd Avenue drains
east (once the trapped lows on 23rd Avenue fill) to Land-O-Lakes Drive. From the intersection
with 23rd Avenue Land-O-Lakes Drive spills to the southeast with a spill elevation of 868.70.
This functionally means that the spill elevation of the Waterfront SWMF is 868.70 not 868.67.
1.4.3 Land-O-Lakes Drive, Catchbasins and Overland Flow
Southeast of the 23rd Avenue on Land-O-Lakes Drive are two catchbasins with a rim elevation
of 868.08 which drain through the pipe network to the Waterfront SWMF. Southeast of these
catchbasins the high point in the Land-O-Lakes drive gutter is 868.36. The points of concern
are:
there will be ponding, maximum depth of 0.28 metres, in Land-O-Lakes Drive if the
Waterfront SWMF is filled at or above 868.08.
the Waterfront SWMF will drain out through the pipe system at the catchbasins in Land-
O-Lakes Drive. This has largely been mitigated by installing an elastomeric check valve
in the pipe at the first manhole the catchbasins drain to.
1.4.4 21st Avenue, Catchbasins and Overland Flow
There are two catchbasins on 21st Avenue located northeast of the existing church that drain to
the Waterfront SWMF. The rims of these catchbasins are set at 867.49 and 867.48 according
to the record drawings. There is not a concern of flooding as the high point in the 21st Avenue
gutter is to the west with a spill elevation is 867.719. The points of concern are:
there will be ponding, maximum depth of 0.24 metres, in 21st Avenue if the Waterfront
SWMF is filled at or above 867.48.
the Waterfront SWMF will drain out through the pipe system at the catchbasins in 21st
Avenue. This has largely been mitigated by installing an elastomeric check valve in the
pipe at the first manhole north of the Waterfront SWMF.
1.4.5 Home Hardware, Onsite Stormwater Management
The Home Hardware onsite stormwater management system is connected to the Waterfront
SWMF through the piped system north of the Waterfront SWMF which is the same piped
system that the 21st Avenue catchbasins tie into. It also is protected by the elastomeric check
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valve that prevents the Waterfront SWMF spilling to 21st Avenue. The Home Hardware onsite
stormwater management system has the following critical rim elevations and inverts:
Bottom of loading dock ramp 868.00,
Catchbasin at the southeast corner of the building 868.50,
Catchbasins at the northeast corner of the building 868.50,
Catchbasin west of the building 868.61,
Catchbasin at the northwest corner of the building 868.35,
Primary concern is that these will not drain when the Waterfront SWMF is filled above these
elevations.
1.4.6 23rd Avenue Spill Elevation and Low Point
The overland spill elevation on 23rd Avenue is 868.67 which matches the Waterfront SWMF
spill elevation. The low spot on 23rd Avenue adjacent to the Waterfront SWMF with catchbasins
located on each side of the road has an elevation of 868.384.
Under zero release conditions, for a runoff event that fills the Waterfront SWMF to an elevation
above 868.384 there will be standing water on 23rd Avenue until permission could be received
to release the water stored.
1.4.7 Westgate Drive, Catchbasins
There are two catchbasins located on Westgate Drive approximately 40 metres south of 23rd
Avenue. The rim elevation of these catchbasins is 868.341 which is 0.329 metres below the
Waterfront SWMF spill elevation.
Under zero release conditions, for a runoff event that fills the Waterfront SWMF to an elevation
above 868.341 there will be standing water on Westgate Drive until permission could be
received to release the water stored.
1.5. Goals of the Stormwater Management System
The goals of the stormwater management system are to:
1. Protect the public,
2. Minimizing property and infrastructure damage from runoff events,
3. Protect the Environment,
4. Allow for development of the Subject Property,
5. Minimize inconvenience to the public,
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2.
SITE ANALYLSIS
2.1. Existing Storm Improvements
The existing stormwater infrastructure consists of:
Parkside Trunk and its downstream facilities,
Piped storm sewer in 21st Avenue,
South ditch along Highway #3 and its downstream facilities,
Waterfront SWMF,
Waterfront development piped storm sewer,
Westgate dry pond,
Westgate development piped storm sewer,
North piped storm sewer from McDonalds to the Waterfront SWMF,
Trapped lows and overland drainage in the Waterfront and Westgate developments,
Onsite detention on developed commercial lands.
2.1.1 Existing Westgate SWMF
Information on the existing Westgate SWMF was taken from the contours on the Westgate
Landing, Record Drawings, December 15, 2013, and is presented in Table 3 respectively.
Table 3 - Existing Westgate SWMF Stage Storage
Description
Elevation
(m)
Depth from
Bottom
(m)
Area
(m2)
Active
Volume
(m3)
Pond Bottom
866.6
0
168
0
866.8
0.2
249
41
867
0.4
353
101
867.2
0.6
479
184
867.4
0.8
626
294
867.6
1
792
436
867.8
1.2
978
613
868
1.4
1,183
828
868.2
1.6
1,412
1088
868.4
1.8
1,680
1396
868.6
2
2,085
1772
Spill Elevation
868.67
2.07
2,139
1920
Top of Bank
868.8
2.2
2,355
2212
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2.1.2 Existing Waterfront SWMF
Information on the existing Waterfront SWMF was taken from the contours on the Westgate
Landing, Record Drawings, December 15, 2013, and is presented in Table 4.
Table 4 - Existing Waterfront SWMF Stage Storage
Description
Elevation
(m)
Depth from
Bottom
(m)
Area
(m2)
Volume
(m3)
Active
Volume
(m3)
Pond Bottom
864.0
0
6,533
0
0
864.2
0.2
6,750
1,328
0
864.4
0.4
6,957
2,699
0
864.6
0.6
7,167
4,111
0
864.8
0.8
7,381
5,566
0
865.0
1
7,597
7,064
0
865.2
1.2
7,811
8,604
0
865.4
1.4
8,027
10,188
0
865.6
1.6
8,146
11,806
0
865.67
1.67
8358
12,383
865.8
1.8
8,470
13,467
0
Normal Water
Level
866.0
2
8,696
15,184
0
866.2
2.2
9,041
16,957
1,774
866.4
2.4
9,392
18,800
3,617
866.6
2.6
9,751
20,715
5,531
866.8
2.8
10,117
22,701
7,518
867.0
3
10,490
24,762
9,578
867.2
3.2
10,870
26,898
11,714
867.4
3.4
11,257
29,110
13,927
867.6
3.6
11,651
31,401
16,217
867.8
3.8
12,053
33,771
18,588
868.0
4
12,461
36,223
21,039
868.2
4.2
12,877
38,756
23,573
868.4
4.4
13,300
41,374
26,190
868.6
4.6
13,731
44,077
28,893
Spill Elevation
868.67
4.67
13,934
45,045
29,861
Top of Bank
868.8
4.8
14,165
46,871
31,688
The IMP indicates current storage of 32,500 m3 in the Waterfront Pond at the approximate spill
elevation of 868.7. How the IMP calculated storage is covered in Section 1.2.3. As the
volumes presented in Table 4 are calculated form the record drawings instead of a simplified
approximation used in the IMP, they are more accurate and relevant. The active storage
volume of 29,861 at an elevation of 868.67 presented in Table 4 is comparable to the stated
design goal of 29,860 present in Table 2.
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2.1.1 Existing Highway #3 South Ditch
Information on existing Highway #3 south ditch was taken from contours from available LIDAR
information and is presented in Table 5. The outlet from this ditch is a 600mm diameter culvert under
Land-O-Lakes Drive draining to the Highway #3 ditch east of Land-O-Lakes Drive. The Highway #3
ditch east of Land-O-Lakes Drive drains north across Highway #3 through a 600mm diameter culvert.
Field reconnaissance of these culverts conducted by MGCL in November 2022 showed that the
culvert crossing Land-O-Lakes drive is approximately 50% sedimented in and the culvert crossing
Highway #3 is approximately 25% sedimented in. Both culvert's inlets also have tall vegetation that
during a major runoff event could block a substantial amount of flow into these culverts.
The existing Highway #3 ditch receives flows from west of 30th Street and from Highway #3 lanes in
addition to the runoff from the ASP lands.
Table 5 - Existing Highway #3 South Ditch Stage Storage
Description
Elevation
(m)
Depth from
Bottom
(m)
Area
(m2)
Active
Volume
(m3)
Pond Bottom
866.8
0
122
0
867
0.2
459
54
867.2
0.4
966
194
867.4
0.6
1,594
447
867.6
0.8
2,324
837
867.8
1
2,461
1315
Spill Elevation
868
1.2
3,959
1951
3.
MODELING
3.1. Design Storms
The design of the different components of a stormwater management system are to meet the flows
and volumes from the storms laid out in Table 6.
Table 6 - Design Storms
Stormwater Infrastructure
Designed For
Design Event
Minor System Conveyances
Peak Flow
1:5-year 4-hour Chicago Storm1
Major System Conveyances
Peak Flow
1:100-year 4-hour Chicago Storm2
Stormwater Management
Storage Facilities
Total Runoff Volume with
release only after the end of
the Storm Event or as
approved by the Town of
Coaldale
1:100-year Chicago Storm (120.14 mm in
24 hours)3 4
1 City of Lethbridge Design Standards 2021 Edition, 3.3.2.1
2 City of Lethbridge Design Standards 2021 Edition, 3.3.2.1
3 City of Lethbridge Design Standards 2021 Edition, 3.3.2.1
4 Malloy Drain Master Drainage Plan, 2010, MPE Engineering Ltd. Table 3.2
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3.2. Sub-catchments
The catchment area of the ASP Area was divided into sub-catchment areas based on existing and
proposed topography and stormwater management features. Where possible sub-catchment from
existing plans were used. Parameters used in modelling were taken from the City of Lethbridge,
Design Standards, where applicable. General parameters used in the modelling of sub-catchments
are presented below:
Slope .......................................................... 0.5%
N Impervious .............................................. 0.013
N Pervious ................................................. 0.15
Depression Storage Impervious ................ 0.45mm
Depression Storage Pervious .................... 1.0mm
Infiltration Method ...................................... Green Ampt
Undeveloped:
Suction Head (mm) ........................... 292.2
Hydraulic Conductivity (mm/hr.) ....... 0.5
Initial Deficit ..................................... 0.25
Developed:
Suction Head (mm) ........................... 88.9
Hydraulic Conductivity (mm/hr.) ....... 3.4
Initial Deficit ..................................... 0.25
3.3. Model Setup
The PCSWWM model set up is presented in Figure 4.
The current Lethbridge 1:100-year Chicago 24-hour storm was modeled, and the duration of the
model run was 144 hours. The explanation for use of only one storm is, the largest volume event is
the most critical event for the major SWMF sizing which is the focus of this SWMP modeling. The
reason for using such a long duration was to ensure that all the runoff volume made it into the storage
ponds.
The Waterfront SWMF, Westgate SWMF and Highway #3 south ditch were modeled using the stage
storage curves presented in Table 3, Table 4, Table 5 and respectively. The 30ST_W-Ditch was
modeled using a functional curve to represent current ditch storage.
The outlet control on the Highway #3 ditch was modeled as the 600mm diameter culvert. It is
recognized that there are additional areas flowing into the Highway #3 ditch such as the runoff from
highway lanes and the Highway #3 ditch west of 30th Street however these have not been included in
the model as the purpose of including the Highway #3 ditch in the model was to demonstrate the
value in removing some areas that currently flow to this ditch. The purpose was not to comment on
whether the ditch and culverts have adequate capacity.
Models were run with the Waterfront SWMF outlet orifice deleted to simulate a zero-release condition.
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3.3.1 Changes Made from Predevelopment to Post-development Interim Model
Figure 5 presents the PCSWWM model setup for the Post-development Interim model. The following
changes were made to the Predevelopment Model to the Post development Model:
To account for Area8 sub-catchment not being able to drain overland across Area4 once it is
developed:
The ditch from 30th Street to the Waterfront SWMF was deleted,
A storage was added to represent the 30th Street east ditch to provide peak flow
attenuation of the 1:100-year runoff to the 1:5-year runoff. Modeling estimated 154 lps
peak runoff from Area8 for a 1:5-year, post-development, runoff event and that 270 m3 of
storage would be required to attenuate the peak runoff from a 1:100-year runoff event.
A 300mm diameter pipe was added from 30th Street to the Waterfront SWMF.
The Area8 sub-catchment impervious percentage was increased from 25% to 35% mostly to
account for improvements to 30th Street. It is noted that most of Area8 is existing country
residential and the 25% impervious area was calculated from measuring the impervious area
from air photos.
Table 7 - Proposed Preliminary Design of Waterfront SWMF
Description
Elevation
(m)
Depth from
Bottom
(m)
Area
(m2)
Volume
(m3)
Active
Volume
(m3)
Forebay Bottom
862.67
0
313
0
863.00
0.33
408
119
863.50
0.83
555
358
863.99
1.32
727
672
Existing Pond Bottom
864.00
1.33
7988
709
864.50
1.83
8471
4,823
865.00
2.33
9056
9,203
865.50
2.83
9744
13,902
Normal Water Level (NWL)
865.67
3
10002
15,581
0
866.00
3.33
10535
18,969
3,388
866.50
3.83
11429
24,459
8,878
867.00
4.33
12426
30,421
14,840
867.50
4.83
13526
36,907
21,326
Design High Water Level (DHWL)
868.00
5.33
14728
43,968
28,387
868.30
5.63
15499
48,502
32,921
868.50
5.83
16033
51,655
36,074
Spill Elevation
868.67
6
16501
54,420
38,839
Top of Bank
869.00
6.33
17441
60,020
44,439
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The Waterfront Pond:
NWL was lowered from 866.00 to 865.67 to increase the storage available by 2,800
m3 in the existing footprint by and improve the backwater conditions in the pipe
network in the Westgate development.
increased in size to be able to accommodate the existing and proposed development
flows being stored below a HWL of 868.00. The proposed design that was used in
the modeling is shown in Table 7.
The Area4 sub-catchment impervious percentage was change from 0% in the Pre-
development model to 60.0% and represents full development of the property.
The Area7 sub-catchment impervious percentage was change from 15% in the Pre-
development model to 85.0% which represents full development of the property.
The 30ST_E-Ditch and 30ST_W-Ditch were modeled using a functional curve to represent
future ditch storage.
The NWL is the Waterfront SWMF was lowered to 865.67.
3.3.2 Post-development Model Full Build Out
Figure 6 presents the PCSWWM model setup for the Post-development Full Build Out model
with a developed Area7 draining to Waterfront SWMF. This model was set up to demonstrate
what the HWL would be in the Waterfront SWMF that was designed for a HWL 0f 868.00
without Area7 added. The reasoning behind this is that by the time Area7 goes for
development the Town will likely have completed sufficient works in the Malloy Drain to allow a
release rate during a storm event from the Waterfront SWMF which would reduce the storage
required in the Waterfront SWMF. However, the Waterfront SWMF is designed to accept
drainage form Area7 to a HWL of 868.30 with a zero-release rate.
To provide a point of information this model was also run with an outlet to the Waterfront SWMF
with the flow being restricted to 2.0 lps/ha (75.6 lps)
3.4. Model Results
3.4.1 Predevelopment Sub-catchments
The parameters that vary from sub-catchment area to sub-catchment area and the modeled
runoff from the predevelopment model is presented in Table 8.
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Table 8 - Pre-Development - Model Results Sub-catchments
Name
Area (ha)
Width
(m)
Flow
Length
(m)
Impervious
(%)
Runoff
Volume
(ML)
Peak
Runoff
(L/s)
Runoff
Coefficient
Draining to Parkside Trunk
Area1
4.20
150
280
72
4.33
1,842
0.86
Sub Total
4.20
4.33
0.86
Weighted Average =
72
0.86
Draining to Highway #3 Ditch
Area7
4.22
160
264
15
3.31
800
0.65
Area9
1.37
130
105
85
1.52
951
0.92
Sub Total
5.59
4.83
Weighted Average =
32.1
0.72
Draining to Waterfront SWMF
Area2
3.69
150
246
60
3.13
1,057
0.71
Area3
7.58
200
379
60
6.41
1,661
0.70
Area4
13.43
300
448
0
9.26
688
0.57
Area5
1.77
70
252
85
1.96
868
0..92
Area6
1.47
110
134
85
1.63
946
0.92
Area8
3.90
70
557
25
2.62
448
0.56
Area10
1.78
176
102
75
1.88
1,193
0.88
Subtotal
33.62
26.89
Weighted Average =
35.2
0.67
Total =
43.41
36.05
Weighted Average =
38.4
0.70
3.4.2 Post-Development Sub-catchments
Parameters that vary from sub-catchment area and the modeled runoff for the post -
development models are presented in for the post-development without Area7 draining to the
Waterfront SWMF and Table 10 for the post-development full buildout with Area7 draining to
the Waterfront SWMF.
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Table 9 - Post-Development - Model Results - Sub-catchments
Name
Area (ha)
Width
(m)
Flow
Length
(m)
Impervious
(%)
Runoff
Volume
(ML)
Peak
Runoff
(L/s)
Runoff
Coefficient
Draining to Parkside Trunk
Area1
4.20
150
280
72
4.33
1,842
0.86
Sub Total
4.20
4.33
0.86
Weighted Average =
72
0.86
Draining to Highway #3 Ditch
Area7
4.22
160
264
85
4.68
2,029
0.92
Area9
1.37
130
105
85
1.52
951
0.92
Sub Total
5.59
6.20
Weighted Average =
85
0.92
Draining to Waterfront SWMF
Area2
3.69
150
246
60
3.13
1,057
0.71
Area3
7.58
200
379
60
6.41
1,661
0.70
Area4
13.43
300
448
60
11.31
2,636
0.70
Area5
1.77
70
252
85
1.96
868
0.92
Area6
1.47
110
134
85
1.63
946
0.92
Area8
3.90
70
557
35
2.85
524
0.61
Area10
1.78
176
102
75
1.88
1,193
0.88
Subtotal
33.62
29.17
Weighted Average =
60.3
0.72
Total =
43.41
39.7
Weighted Average =
64.64
0.80
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Table 10 - Post Development - Model Results - Sub-catchments with Area7 Draining to the Waterfront SWMF
Name
Area (ha)
Width
(m)
Flow
Length
(m)
Impervious
(%)
Runoff
Volume
(ML)
Peak
Runoff
(L/s)
Runoff
Coefficient
Draining to Parkside Trunk
Area1
4.20
150
280
72
4.33
1,842
0.86
Sub Total
4.20
4.33
0.86
Weighted Average =
72
0.86
Draining to Highway #3 Ditch
Area9
1.37
130
105
85
1.52
951
0.92
Sub Total
1.37
1.52
Weighted Average =
85
0.92
Draining to Waterfront SWMF
Area2
3.69
150
246
60
3.13
1057
0.71
Area3
7.58
200
379
60
6.41
1,661
0.70
Area4
13.43
300
448
60
11.31
2,636
0.70
Area5
1.77
70
252
85
1.96
868
0.92
Area6
1.47
110
134
85
1.63
946
0.92
Area7
4.22
160
264
85
4.68
2,029
0.92
Area8
3.90
70
557
35
2.85
524
0.61
Area10
1.78
176
102
75
1.88
1,193
0.88
Subtotal
37.84
33.85
0.74
Weighted Average =
63.1
0.74
Total =
43.41
39.7
Weighted Average =
64.6
0.80
3.4.1 Models Results - Outlets
Table 11 present the model results at the system outlets and the Waterfront SWMF for catchment
area, peak flows, and runoff volume. Note the assumption is that the Waterfront SWMF has been
converted to a zero-release facility during a storm event for the Pre-development scenario. The peak
flows at the outlets will be much lower than summing the peak runoff from the sub-catchment areas
that contribute to the outlets flow. The reasons for this are:
The PCSWMM model calculates runoff hydrographs and the peak runoff from a sub-catchment
area is reported in Table 8, Table 9 & Table 10.
The hydrographs are routed through downstream sub-catchment areas, conveyances, weirs
and orifices which introduces the time of flow which flattens the hydrograph (the peak is
reduced).
The PCSWMM model adds hydrographs. A primary feature of hydrographs is the time
component. Only when the peak flow occurs at the same time will the peak flow of each
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hydrograph add to result in an output peak flow that is the sum of the inlet peaks. This is a rare
occurrence and the hydrograph resulting from the addition of two or more hydrographs will
have multiple localized peaks but the model will only publish the maximum peak observed in
the hydrograph which will be the summation of all the input flows at the same time and is
typically much lower than if the peak flows are summed.
Figure 8 presents three Hydrographs at the Outlet of STM71 located at the intersection of 21st
Avenue and 25 Street into the Parkside Trunk. The hydrographs clearly show the benefit of
converting the Waterfront SWMF to a 2 lps/ha and zero-release rates.
Figure 9 shows the hydrograph at the Highway #3 ditch outlet for the current drainage area pre-
development and proposed development and clearly shows the benefit of draining as much of Area 7
as practical to the Waterfront SWMF.
Table 12 presents the Waterfront SWMF in its current pre-development conditions against the
proposed design of the Waterfront SWMF.
Table 11 -Model Results - Outlets
Parkside
Trunk
Highway #3
Ditch
Waterfront
SWMF
Total
Predevelopment
Current Outfall
Catchment Area
37.821 ha
5.59 ha
33.617 ha
43.41 ha *
Peak Flow
Discharging
1:5 Year
326 lps
358 lps
243 lps
4.204
1:100 Year
930 lps
789 lps
737 lps
Discharge
Volume
1:5 Year
7,529 m3
1,229 m3
6,230 m3
8,758 m3*
1:100 Year
31,021 m3
5,006 m3
26,600 m3
36,027 m3
Predevelopment
Zero Release for
Waterfront SWMF
Catchment Area (ha)
4.204 ha
5.59 ha
33.617ha
43.41 ha
Peak Flow
Discharging
1:5 Year
159 lps
358 lps
0 lps
1:100 Year
204 lps
789 lps
0 lps
Discharge
Volume
1:5 Year
1,275 m3
1,226 m3
0 m3
2,499 m3
1:100 Year
4,330 m3
4,997 m3
0 m3
9,327 m3
Proposed Post
Development
Catchment Area
4.204 ha
5.59 ha
33.617ha
43.41 ha
Peak Flow
Discharging
1:5 Year
159 lps
635lps
0 lps
1:100 Year
204 lps
953 lps
0 lps
Discharge
Volume
1:5 Year
1,275 m3
1,924 m3
0 m3
3,199 m3
1:100 Year
4,330 m3
6,350 m3
0 m3
10,680 m3
Proposed Post-
Development with
Area 7 added to
Waterfront SWMF
Catchment Area
4.204 ha
1.367 ha
37.84 ha
43.41 ha
Peak Flow
Discharging
1:5 Year
159 lps
216 lps
0 lps
1:100 Year
204 lps
596 lps
0 lps
Discharge
Volume
1:5 Year
1,275 m3
473 m3
0 m3
1,749 m3
1:100 Year
4,330 m3
1,677 m3
0 m3
6,007 m3
*
Waterfront SWMF discharges flows through the Parkside Trunk and is therefore not included in the totals for
the area.
Stormwater Management Plan for
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It is noted that the Active Depth for the Proposed Waterfront SWMF is slightly above the guidelines
recommended depth of 2.0 m. This is often done in the Lethbridge region and has not shown
problems when handling large infrequent storm events.
Table 13 presents the modeled performance of the Waterfront SWMF for predevelopment and post-
development model runs. It is noted that the modeled response shown in Table 13 shows the
proposed Waterfront SWMF filling 867.90 and not to the DHWL of 868.00. This is due to continuity
error for the flow routing in the model where approximately 949 m3 of runoff has been lost. Industry
practice is that continuity errors less than 2% are not relevant. However due to the Towns concerns
the design of the Waterfront SWMF will accommodate the calculated runoff volume at the DHWL and
not what the modeling shows for stored volume during the design runoff event and the resultant HWL.
Figure 8 - Parkside Trunk Outlet
Stormwater Management Plan for
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Figure 9 - Highway 3 Outlet
Table 12 - Waterfront SWMF Design
Design
Current Waterfront
SWMF
Proposed Waterfront SWMF
Pond Bottom
864.00 m
864.00 m (Forebay 862.67 m)
NWL
866.00 m
865.67 m
Design High Water Level (DHWL)
868.00 m
868.00 m
Spill Elevation
868.67 m
868.67 m
Permanent Depth
2.00 m
1.67 m (Forebay 3.00 m)
Active Depth (DHWL-NWL)
2.00 m
2.33 m
Height to Spill Elevation (freeboard)
0.67 m
0.67 m
Permanent Volume (below NWL)
15,184 m³
15,581 m³
Total Volume at DHWL
36,223 m³
43,968 m³
Total Volume to Spill Elevation
45,045 m³
54,420 m³
Active (Stored) Volume
21,039 m³
28,387 m³ *
Volume from (Spill Elevation - DHWL)
8,822 m³
10,452 m³
Extra Capacity above DHWL
42.8%
37.0%
*
From Table 3 the Westgate SWMF has an active volume of 866 m3 at the DHWL making the total
active volume of the Waterfront SWMF system 29,215 m3 which is greater than the required
storage volume of 29,170 listed in Table 9.
Stormwater Management Plan for
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Table 13 - Waterfront SWMF Modeled Performance
Proposed Waterfront SWMF Post Development
865.67
15557
866.6
868.67
54334
868.67
1920
with Area 7 and a
2.0 lps/ ha Release
Rate
Westgate
Dry Pond
867.86
1.26
0.81
679
679
1,241
28,009
12,688
45%
0.0%
0.0%
Waterfront
SWMF
867.87
2.20
0.80
42,887
27,330
11,447
with Area 7
Westgate
Dry Pond
868.18
1.58
0.49
1,068
1,068
852
31,908
8,789
28%
0.0%
1.3%
Waterfront
SWMF
868.18
2.51
0.49
46,397
30,840
7,937
without Area 7
Westgate
Dry Pond
867.91
1.31
0.76
724
724
1,196
27,438
13,259
48%
0.0%
1.1%
Waterfront
SWMF
867.91
2.24
0.76
42,271
26,714
12,063
Current Waterfront SWMF
Predevelopment
866.00
15604
866.6
868.67
45045
868.67
1920
Zero - Release
During Storm
Westgate
Dry Pond
868.30
1.70
0.37
1,236
1,236
684
25,680
5,681
22%
0.0%
0.8%
Waterfront
SWMF
868.30
2.30
0.37
40,048
24,444
4,997
Current Condition
(0.6m Orifice)
Westgate
Dry Pond
867.68
1.08
0.99
500
500
1,420
10,921
20,440
187%
0.0%
0.0%
Waterfront
SWMF
867.12
1.12
1.55
26,025
10,421
19,020
Waterfront SWMF NWL
Permanent Pool Volume
Westgate Dry Pond Bottom
Waterfront SWMF Spill Elevation
Waterfront SWMF Total Volume
@ Spill Elevation
Westgate Dry Pond Spill Elevation
Westgate Dry Pond Total Volume
@ Spill Elevation
Modeled Response
1:100-year HWL
1:100-year Active Depth (m)
1:100-year Height to Spill (m)
(freeboard)
1:100-year Total Volume (m3)
1:100-year Active (Stored) Volume
(m3)
Volume from Spill Elevation -
1:100-year HWL (m3)
Total 1:100-year Active (m3)
(Stored) Volume
Total Volume from Spill Elevation
- 1:100-year HWL (m3)
Additional Capacity to Spill
Elevation (m3)
Continuity Error Runoff
Continuity Error Routing
Stormwater Management Plan for
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Figure 10 presents the peak flows and volumes for the Post-development model with Area 7
developed and draining into the Waterfront SWMF.
4.
PROPOSED STORMWATER MANAGEMENT SYSTEM
Following the guidance of applicable standards and the results of modelling the stormwater management
system in the ASP area the following improvements are proposed
4.1. Offsite Stormwater Management System Improvements
Except for the improvements required to the Waterfront SWMF discussed below, further development
of the ASP lands will require no downstream infrastructure improvements. When the proposed
infrastructure improvements are made, storm infrastructure downstream of the ASP lands will see a
reduction peak flows from the ASP lands.
Runoff from Area8 which is upstream of the ASP Lands will be accommodated by:
The storm main in 23rd Avenue will be designed to accommodate peak flows from the 1:5-year
post development runoff, estimated at 154 lps (predevelopment estimated at 133)
23rd Avenue will be designed to accommodate peak flows greater than the from the
1:5-year event runoff on the road, curb and gutters,
The runoff volume from Area8 has been included in all SWMF calculations.
4.2. Area 4
The stormwater management system in Area4 planned as a dual drainage (major / minor) system
which is typical of urban developments in Alberta.
The minor system is planned to be designed to accommodate the Lethbridge 1:5-year runoff event
without surcharging, including surcharge from the Waterfront SWMF. The major system will be
designed to accommodate the Lethbridge 1:100-year, Chicago-4-hour storm and the Lethbridge
1:100-year, Chicago 24-hour storm.
Overland flow on streets, trapped lows on the roads will be designed and used as necessary to
convey and attenuate the 1:100 year, Chicago 4-hr Storm as may be required. Onsite detention will
be required for commercial and multi-family sites except where it can be demonstrated to the Town's
satisfaction, by modeling that the site can discharge at a higher rate and not cause surcharge in the
minor system or discharge directly to the SWMF without causing icing on pedestrian trails or erosion
issues.. This typically only works for sites immediately adjacent to a SWMF where overland flow
directly to the SWMF is practical.
The stormwater management plans for the Malloy Pond 2 show the emergency overflow directed to
30th Street, see Figure 14, and draining through Area4. To address this 23rd Avenue will be designed
to safely convey overland flows of at least 2.0 m3/s to the Waterfront SWMF. The Malloy 2 Pond is
designed to drain to the Birds of Prey Wetland and only during extreme runoff exceeding the current
design standards will the emergency spill way be used.
Stormwater Management Plan for
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4.3. Waterfront SWMF
It is proposed that the Waterfront SWMF be converted to a zero-release during a storm event facility
to reduce the pressure on the Town's stormwater system downstream. This change should be done
whether development proceeds or not and therefore development is not a trigger. Development will
worsen any issues caused by the current Waterfront SWMF outlet configuration.
The layout, design and equipment of the control structure will be determined during the detailed
design for the expansion of the Waterfront SWMF unless the Town undertakes this work on their own.
The cost of converting the Waterfront SWMF to a zero-release facility is estimated at $40,000 and
includes installing a new vault structure in the grass on the berm, a control gate operatable from the
surface and a weir set at the HWL. This control gate should be designed so that in the future it can
be set for a controlled release during a storm event.
It is proposed that the Waterfront SWMF NWL be reduced to 865.66 which matches the maximum
invert in the downstream piped stormwater system. The reason for this change is to reduce the
amount of surcharging in the Westgate stormwater collection system at the NWL. It also adds some
active storage volume to the Waterfront SWMF. This can easily be achieved by cutting a slot in the
existing orifice plate to the invert of the manhole or with more work the plate can be cutup and
removed through the manhole lid.
To accommodate the post development runoff from Area4 below an elevation of 868.00 the
Waterfront SWMF will need to be expanded a minimum of 7,745 m3. It is proposed that this be done
by:
lowering the NWL of the Waterfront SWMF from 868.00 to 865.57, as this also improves some
of the other issues in the area.
expanding the pond in the southwest corner. A concept of the expansion to provide the
required storage is shown in Figure 11.
With the new pond levels there are three concerns to be addressed:
1. The pond currently does not appear to be armored at the NWL against erosion. Shoreline
erosion control will be addressed during the detailed design.
2. The minimum depth of the permanent pool will no longer be in the recommended range of 2.0 to
3.0 m. To address this a small forebay pool will be excavated as part of the pond expansion in
the southwest corner to a depth of approximately 3.0m.
3. The active depth of the Waterfront SWMF will be 2.33 metres which is greater than the 2.0
metres recommended in the Alberta Environment and Parks, Standards and Guidelines for
Municipal Water Works, Wastewater and Storm Drainage Systems. Considering:
the design event that would fill the Waterfront SWMF has a 1.0% probability of
occurrence (1:100-year event) it will be very rare that the pond will be filled to capacity,
human safety due to a slightly higher water level rise is not a concern, however posting
warning signs at HWL level stating that the water is designed to rise to this level provides
both information for the public to stay out of the potential flooding area and provides
public education on the operation of the pond,
Stormwater Management Plan for
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4.4. Area 7
The stormwater management system in Area7 is projected to be a dual drainage (major / minor)
system which is typical of urban developments in Alberta when it is developed. Currently Area7
drains to the Highway 3 ditch and there is no requirement on Area 4 to accommodate drainage from
Area7.
There is sufficient grade for a large portion of Area 7 to be drained into the Waterfront SWMF and
away from the Highway #3 ditch. There is adequate capacity in the Waterfront SWMF to
accommodate runoff from Area7 if the HWL is allowed to increase to 868.3 metres or an allowable
release rate of no less than 2 lps/ha is provided. How best to accommodate the drainage from Area 7
to the Waterfront SWMF has not been determined.
4.5. General Layout of the Proposed Stormwater Management System
4.5.1 Minor System & Waterfront SWMF
Figure 11 - Waterfront SWMF Conceptual Design
Figure 12 presents the general minor system proposed for the development of Area4 (the
Subject Site). It is noted:
The minor system is a conventional piped system designed not to surcharge during a 1:5-
year return period rainfall event.
A new outlet to the Waterfront SWMF is proposed.
The piped system in 23rd Avenue has been extended to 30th Street to convey flows from
Area 8.
No connection to Area7 is proposed. Provisions for future connections to the Waterfront
SWMF to be examined during detailed design.
4.5.2 Major System
Figure 13 presents the general major system proposed for the development of Area 4. It is
noted:
for the commercial and multi-family sites onsite detention is required,
for single family residential and the roads trapped low storage on the roads is proposed,
ditch or trapped low storage is required for Area8 as the piped system in Area4 will be
designed to convey the minor event peak flow in the pipe.
23rd Avenue will be designed as an overland flow route to accommodate flows from
Area8 greater than the capacity of the minor system to accommodate and the potential of
2.0 m3/s flows from the Malloy 2 pond.
4.5.3 Emergency System
Figure 14 presents the general emergency storage and overland flow. It is to be noted:
There is a potential from an emergency overflow from the Malloy 2 Pond,
The emergency spill elevation on Land O' Lakes Drive has not changed,
The emergency spill from Area7 is to Highway #3.
Stormwater Management Plan for
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4.5.4 Wet Pond Make-up Water
The Waterfront SWMF currently receives make-up-water from an SMRID turnout shown on
Figure 3. This turnout and its piped supply line will be removed during development.
The makeup water supply lost through development will be replaced by a new SMRID turnout
will be provided on 30th Street, as shown on Figure 12. This turnout will discharge to the storm
sewer in 23rd Avenue which flows to the Waterfront SWMF.
Removal of the SMRID line and turnouts on the ASP Area and installing a new turnout require
approval and coordination with SMRID.
4.6. How the Proposed Stormwater Management System Addresses Issues
In section 1.4 Stormwater Management Issues several points of concern in the Waterfront SWMF
catchment area were raised. How the proposed system is addressing these issues is described
below.
4.6.1 Waterfront SWMF
The recommendation is being made to line the west side of the Waterfront SWMF.
A new control structure is being recommended that will allow release rates to be set including
the option of zero-release during a storm event.
4.6.2 Waterfront SWMF Spill Elevation
This report acknowledges that the overland spill from the Waterfront SWMF is 868.67. Whether
the 30mm in difference in spill elevation will make a noticeable difference during an emergency
event has not been examined. However, returning the Waterfront SWMF to a design HWL of
868.00 will help to make an event that will spill overland from the Waterfront SWMF a truly rare
event. It is beyond the scope of this report to estimate what that event may look like.
4.6.3 Land-O-Lakes Drive, Catchbasins and Overland Flow
Returning the Waterfront SWMF to a design HWL of 868.00 will reduce the frequency of
ponding at these catchbasins. Spill from the Waterfront Pond through these catchbasins will
only occur if the water surface elevation in the Waterfront Pond has exceeded the HWL which
has been calculated to accommodate the 1:100-year 24-hr rainfall event and the backflow
prevention valve fails.
4.6.4 21st Avenue, Catchbasins and Overland Flow
Without excessive expenditures to lower the storm system downstream of the Waterfront
SWMF which would allow a lowering of the Waterfront SWMF there is little that can be done to
eliminate the issues identified here. Returning the HWL of the Waterfront SWMF to 868.00 will
reduce the frequency of the outlined issues.
4.6.5 Home Hardware, Onsite Stormwater Management
Returning the HWL of the Waterfront SWMF to 868.00 will eliminate the issues up to and
including the 1:100-year 24-hr rainfall event.
Stormwater Management Plan for
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4.6.6 23rd Avenue Spill Elevation and Low Point
Returning the HWL of the Waterfront SWMF to 868.00 will eliminate the issues up to and
including the 1:100-year 24-hr rainfall event.
4.6.7 Westgate Drive, Catchbasins
Returning the HWL of the Waterfront SWMF to 868.00 will eliminate the issues up to and
including the 1:100-year 24-hr rainfall event.
5.
PHASING AND TRIGGERS FOR NEW STORMWATER INFRASTRUCTURE
5.1. Area4 (Subject Property)
Development of Area4 will trigger the requirement for the following improvements to stormwater
infrastructure:
1. Increasing the size of the Waterfront SWMF. If the Waterfront SWMF outlet control has not been
upgraded, it should be done in conjunction with the pond expansion. Lining the west bank of the
Waterfront pond and installing any shoreline armoring should also be done at the time of the
pond expansion.
2. Installation of a new piped inlet into the Waterfront SWMF as the current inlets are not sized to
accommodate Area4.
3. Installation of a new piped stormwater collection system in Area4 as the property is developed,
4. Extension of the storm collection system to 30th Street by:
a. Extending the piped stormwater collection system in 23rd Avenue as each phase of
development, and or
b. Creating an interim drainage ditch from 30th Street to the furthest extent of the piped
stormwater collection system in 23rd Avenue built during each phase of development.
5. Grading the ditch in 30th Street to provide 270 m3 of storage and conveyance of runoff to the
stormwater collection system located in 23rd Avenue.
5.2. Future Commercial (Area 7)
Development of Area 7 will trigger the requirement for stormwater management infrastructure being
installed in Area 7.
6.
RECOMENDATIONS
1. With respect to the Waterfront SWMF:
a. The outlet should be modified to provide for a controlled release rate with the controls designed
so that no release from the Waterfront pond is possible.
b. The NWL is reduce to 865.67 by cutting a slot in the orifice plate in the outlet control manhole
to the invert of the manhole,
c. The active storage volume is increased to 28,387 m³ below a water surface elevation of 868.00,
Stormwater Management Plan for
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d. Appropriate shoreline erosion protection be installed,
e. Signage be installed at the high-water level to warn and educate the public on the elevation of
expected flooding.
2. With respect to the development of Area 4:
a. Area 4 be developed with a major / minor stormwater management system,
b. 1:5-year runoff from Area 8 west of Area 4 be accommodated in the Area 4 minor storm system,
c. Flows greater than the 1:5-year runoff from Area 8 west of Area 4 be accommodated in storage
constructed in Area 8.
d. 23rd Avenue be designed to accommodate emergency overland flows from Area 8 and the
Malloy 2 Pond.
e. Consideration of servicing Area7 through Area4 will be examined with detailed design.
Stormwater Management Plan for
West Coaldale Future Development Area ASP
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Management Plan - West Coaldale Subdivision Feb 14 2023.docx
APPENDIX A Figures
Figure 1 - 2022 ASP Amendment Proposed Land Use Map
Figure 2 - IMP Catchment Areas
Figure 3 - Existing Stormwater Drainage Conditions
Figure 4 - PCSWMM Model Setup - Pre-Development
Figure 5 - PCSWMM Model Setup - Post Development - Interim
Figure 6 - PCSWMM Model Setup - Post Development - Full Build Out
Figure 7 - Pre-development Offsite Inflows and Outflows
Figure 8 - Parkside Trunk Outlet Hydrograph
Figure 9 - Highway 3 Outlet Hydrograph
Figure 10 - Proposed SWMP Offsite Inflows and Outflows
Figure 11 - Waterfront SWMF Conceptual Design
Figure 12 - Stormwater Minor System Plan
Figure 13 - Stormwater Major System Plan
Figure 14 - Stormwater Emergency Storage and Overland Drainage Plan
Tim
Hortons
McDonald's
CHURCH
Home
Hardware
Waterfront
SWMF
Westgate Dry Pond
255-31st Street North Lethbridge, Alberta T1H 3Z4
Ph: (403) 329-0050 E-mail: [email protected] Fax: (403) 329-6594
Consulting Engineers, Planners, and Land Surveyors
2022 ASP AMENDMENT PROPOSED LAND USE MA
FIGURE 1.0
Dec 01, 2022
Stormwater Management Plan
West Coaldale ASP Ammendment 2022
229648CE
LEGEND
ASP BOUNDARY (Area=39.52 ha)
Highway 3
24 St
Westgate Dr
Westgate Dr
Westgate Cres
Westgate Cres
Land O' Lakes Dr
Land O' Lakes Dr
24 Ave
25 Ave
23 Ave
22 Ave
21A Ave
25 St
21 Ave
21 Ave
Waterfront
Landing
Waterfront
Landing
24 St
23 Ave
23 Ave
30 St
30 St
30 St
Crowsnest Highway
CURRENT DEVELOPMENT
BOUNDARY
ha
AREA (ha)
ac
7.06
4.37
26.24
18.85
10.86
5.21
INSTITUTIONAL / RECREATIONAL (I/R)
UTILITY (U)
SMALL LOT RESIDENTIAL (R-1B)
RESIDENTIAL (R-1A)
HIGHWAY COMMERCIAL (C-2)
2.86
1.77
2.11
10.62
7.63
PROPOSED LAND USE
RESIDENTIAL MULTI-UNIT (R-2)
4.40
INDICATES AREAS THAT WILL REQUIRE A
CHANGE IN LAND USE
1.75
RESIDENTIAL STARTER LOTS (R-1C) 0.71
ROADWAYS & LANES
9.43
23.29
TOTAL ASP AREA:
39.51
97.64
255-31st Street North Lethbridge, Alberta T1H 3Z4
Ph: (403) 329-0050 E-mail: [email protected] Fax: (403) 329-6594
Consulting Engineers, Planners, and Land Surveyors
IMP CATCHMENT AREAS
Stormwater Management Plan
West Coaldale ASP Ammendment 2022
LEGEND
ASP BOUNDARY (Area=39.52 ha)
Highway 3
24 St
Westgate Dr
Westgate Dr
Westgate Cres
Westgate Cres
Land O' Lakes Dr
Land O' Lakes Dr
24 Ave
25 Ave
23 Ave
22 Ave
21A Ave
25 St
21 Ave
21 Ave
Waterfront
Landing
Waterfront
Landing
24 St
23 Ave
23 Ave
30 St
30 St
30 St
Crowsnest Highway
M
I
Q
F
A
IMP CATCHMENT AREAS
G
FIGURE 2.0
Dec 01, 2022
229648CE
ø
255-31st Street North Lethbridge, Alberta T1H 3Z4
Ph: (403) 329-0050 E-mail: [email protected] Fax: (403) 329-6594
Consulting Engineers, Planners, and Land Surveyors
EXISTING STORMWATER DRAINAGE CONDITION
Highway 3
24 St
Westgate Dr
Westgate Dr
Westgate Cres
Westgate Cres
Land O' Lakes Dr
Land O' Lakes Dr
24 Ave
25 Ave
23 Ave
22 Ave
21A Ave
21A Ave
25 St
21 Ave
21 Ave
Waterfront
Landing
Waterfront
Landing
24 St
23 Ave
30 St
30 St
30 St
Crowsnest Highway
PRE-DEVELOPMENT
FUTURE
COMMERCIAL
Area'10'
SWMF
To Parkside Acres
Stormwater Facility
Area '4'
13.38 ha
Area '7'
4.22 ha
Area '3'
7.48 ha
Area '1'
4.21 ha
Area '5'
1.77 ha
Area '2'
3.67 ha
1.81 ha
To Birds of Prey
Wetlands Facility
To Birds of Prey
Wetlands Facility
Area '9'
1.37 ha
Stormwater Management Plan
West Coaldale ASP Ammendment 2022
Area '6'
1.47 ha
Area '8'
3.90 ha
LEGEND
STORM MANHOLE AND PIPE
AREA '1'
EXISTING UTILITIES
STORM MANHOLE AND PIPE
FUTURE UTILITIES
SUB-CATCHMENTS
AREA '2'
AREA '3'
AREA '4'
AREA '5'
AREA '6'
AREA '7'
AREA '8'
AREA '9'
SWMF
EXISTING CHANNEL
EX SMRID TURNOUT FOR
WATERFRONT SWMF
MAKEUP WATER
EXISTING SMRID PIPE
AND TURNOUT
FIGURE 3.0
Dec 01, 2022
229648CE
ø
255-31st Street North Lethbridge, Alberta T1H 3Z4
Ph: (403) 329-0050 E-mail: [email protected] Fax: (403) 329-6594
Consulting Engineers, Planners, and Land Surveyors
PRE-DEVELOPMENT
OFFSITE INFLOW AND OUTFLOWS
Highway 3
24 St
Westgate Dr
Westgate Dr
Westgate Cres
Westgate Cres
Land O' Lakes Dr
Land O' Lakes Dr
24 Ave
25 Ave
23 Ave
22 Ave
21A Ave
21A Ave
25 St
21 Ave
21 Ave
Waterfront
Landing
Waterfront
Landing
24 St
23 Ave
30 St
30 St
30 St
Crowsnest Highway
PRE-DEVELOPMENT
FUTURE
COMMERCIAL
Area'10'
SWMF
To Parkside Acres
Stormwater Facility
Area '4'
13.38 ha
Area '7'
4.22 ha
Area '3'
7.48 ha
Area '1'
4.21 ha
Area '5'
1.77 ha
Area '2'
3.67 ha
1.81 ha
To Birds of Prey
Wetlands Facility
To Birds of Prey
Wetlands Facility
Area '9'
1.37 ha
Stormwater Management Plan
West Coaldale ASP Ammendment 2022
Area '6'
1.47 ha
Area '8'
3.90 ha
From Area (Offsite)
1:5 YEAR
Peak Flow=133 lps
Volume=401 m³
1:100 YEAR
Peak Flow=448 lps
Volume=2630 m³
LEGEND
STORM MANHOLE AND PIPE
AREA '1'
EXISTING UTILITIES
STORM MANHOLE AND PIPE
FUTURE UTILITIES
SUB-CATCHMENTS
AREA '2'
AREA '3'
AREA '4'
AREA '5'
AREA '6'
AREA '7'
AREA '8'
AREA '9'
SWMF
Hwy #3 Discharge
1:5 YEAR
Peak Flow=359 lps
Volume=1,229 m³
1:100 YEAR
Peak Flow=789 lps
Volume=5,006 m³
Parkside Trunk Discharge
1:5 YEAR
Peak Flow=326 lps
Volume=7,529 m³
1:100 YEAR
Peak Flow=929 lps
Volume=31,021 m³
EXISTING CHANNEL
FIGURE 7.0
Dec 01, 2022
229648CE
ø
255-31st Street North Lethbridge, Alberta T1H 3Z4
Ph: (403) 329-0050 E-mail: [email protected] Fax: (403) 329-6594
Consulting Engineers, Planners, and Land Surveyors
Highway 3
24 St
Westgate Dr
Westgate Dr
Westgate Cres
Westgate Cres
Land O' Lakes Dr
Land O' Lakes Dr
24 Ave
25 Ave
23 Ave
22 Ave
21A Ave
21A Ave
25 St
21 Ave
21 Ave
Waterfront
Landing
Waterfront
Landing
24 St
23 Ave
23 Ave
30 St
30 St
30 St
Crowsnest Highway
PROPOSED
DEVELOPMENT
FUTURE
COMMERCIAL
AREA '10'
SWMF
To Parkside Acres
Stormwater Facility
Area '4'
13.38 ha
Area '7
4.22 ha
Area '3'
7.48 ha
Area '1'
4.21 ha
Area '5'
1.77 ha
Area '2'
3.67 ha
1.81 ha
To Birds of Prey
Wetlands Facility
To Birds of Prey
Wetlands Facility
Area '9'
1.37 ha
PROPOSED STORMWATER MANAGEMENT PLA
OFFSITE INFLOWS AND OUTFLOWS
Stormwater Management Plan
West Coaldale ASP Ammendment 2022
Area '6'
1.47 ha
Area '8'
3.90 ha
LEGEND
STORM MANHOLE AND PIPE
AREA '1'
EXISTING UTILITIES
STORM MANHOLE AND PIPE
FUTURE UTILITIES
SUB-CATCHMENTS
AREA '2'
AREA '3'
AREA '4'
AREA '5'
AREA '6'
AREA '7'
AREA '8'
AREA '9'
SWMF
From Area (Offsite)
1:5 YEAR
Peak Flow=154 lps
Volume=517 m³
1:100 YEAR
Peak Flow=524 lps
Volume=2,840 m³
Hwy #3 Discharge
1:5 YEAR
Peak Flow=635 lps
Volume=1,924 m³
1:100 YEAR
Peak Flow=953 lps
Volume=6,350 m³
Parkside Trunk Discharge
1:5 YEAR
Peak Flow=159 lps
Volume=1,275 m³
1:100 YEAR
Peak Flow=204 lps
Volume=4,330 m³
FIGURE 10.0
Dec 01, 2022
229648CE
FLOW ALONG THE GOLF
COURSE CONCEPTUAL
WATERFRONT SWMF CONCEPT
Land O' Lakes Dr
23 Ave
FIGURE 11.0
Dec 01, 2022
229648CE
23 Ave
Waterfront Landing
Westgate Dr
Westgate Cres
ø
255-31st Street North Lethbridge, Alberta T1H 3Z4
Ph: (403) 329-0050 E-mail: [email protected] Fax: (403) 329-6594
Consulting Engineers, Planners, and Land Surveyors
STORMWATER - MINOR SYSTEM
Highway 3
24 St
Westgate Dr
Land O' Lakes Dr
24 Ave
25 Ave
23 Ave
22 Ave
21A Ave
21 Ave
21 Ave
Waterfront
Landing
Waterfront
Landing
24 St
23 Ave
23 Ave
30 St
Crowsnest Highway
FH
Stormwater Management Plan
West Coaldale ASP Ammendment 2022
Highway 3
24 St
Westgate Dr
Westgate Dr
Westgate Cres
Westgate Cres
Land O' Lakes Dr
21A Ave
25 St
21 Ave
21 Ave
Waterfront
Landing
Waterfront
Landing
24 St
23 Ave
23 Ave
30 St
Crowsnest Highway
PROPOSED
DEVELOPMENT
FUTURE
COMMERCIAL
AREA '10'
SWMF
Area '4'
13.38 ha
Area '7'
4.22 ha
Area '3'
7.48 ha
Area '1'
4.21 ha
Area '5'
1.77 ha
Area '2'
3.67 ha
1.81 ha
To Birds of Prey
Wetlands Facility
Area '9'
1.37 ha
Area '6'
1.47 ha
Area '8'
3.90 ha
NEW OUTFALL
LEGEND
STORM MANHOLE AND PIPE
AREA '1'
EXISTING UTILITIES
STORM MANHOLE AND PIPE
FUTURE UTILITIES
SUB-CATCHMENTS
AREA '2'
AREA '3'
AREA '4'
AREA '5'
AREA '6'
AREA '7'
AREA '8'
AREA '9'
SWMF
300 STM
300 STM
450 STM
300 STM
375 STM
300 STM
300 STM
525 STM
525 STM
600 STM
450 STM
675 STM
300 STM
300 STM
300 STM
750 STM
NEW SMRID TURN OUT
FOR WATERFRONT SWMF
MAKEUP WATER
EX. CULVERT TO REMAIN
EXISTING SMRID PIPE
AND TURNOUT
FIGURE 12.0
Dec 01, 2022
229648CE
675 STM
FLOW ALONG THE GOLF
COURSE CONCEPTUAL
ø
255-31st Street North Lethbridge, Alberta T1H 3Z4
Ph: (403) 329-0050 E-mail: [email protected] Fax: (403) 329-6594
Consulting Engineers, Planners, and Land Surveyors
STORMWATER - MAJOR SYSTEM
Highway 3
24 St
Westgate Dr
Land O' Lakes Dr
24 Ave
25 Ave
23 Ave
22 Ave
21A Ave
21 Ave
21 Ave
Waterfront
Landing
Waterfront
Landing
24 St
23 Ave
23 Ave
30 St
Crowsnest Highway
Stormwater Management Plan
West Coaldale ASP Ammendment 2022
Highway 3
24 St
Westgate Dr
Westgate Dr
Westgate Cres
Westgate Cres
Land O' Lakes Dr
21A Ave
25 St
21 Ave
21 Ave
Waterfront
Landing
Waterfront
Landing
24 St
23 Ave
23 Ave
30 St
30 St
Crowsnest Highway
PROPOSED
DEVELOPMENT
FUTURE
COMMERCIAL
AREA '10'
SWMF
Area '4'
13.38 ha
Area '7'
4.22 ha
Area '3'
7.48 ha
Area '1'
4.21 ha
Area '5'
1.77 ha
Area '2'
3.67 ha
1.81 ha
DITCH
TRAPPED
LOW
Area '9'
1.37 ha
Area '6'
1.47 ha
Area '8'
3.90 ha
1:5 YEAR PRE-DEVELOPMENT
FLOW 104 LPS
ONSITE
DETENTION
REQUIRED
ONSITE
DETENTION
REQUIRED
ONSITE
DETENTION
REQUIRED
LEGEND
STORM MANHOLE AND PIPE
AREA '1'
EXISTING UTILITIES
STORM MANHOLE AND PIPE
FUTURE UTILITIES
SUB-CATCHMENTS
AREA '2'
AREA '3'
AREA '4'
AREA '5'
AREA '6'
AREA '7'
AREA '8'
AREA '9'
SWMF
CATCHMENT AREAS
OVERLAND FLOW ROUTE
TRAPPED LOW
FIGURE 13.0
Dec 01, 2022
229648CE
FLOW ALONG THE GOLF
COURSE CONCEPTUAL
ø
255-31st Street North Lethbridge, Alberta T1H 3Z4
Ph: (403) 329-0050 E-mail: [email protected] Fax: (403) 329-6594
Consulting Engineers, Planners, and Land Surveyors
STORMWATER EMERGENCY STORAG
Highway 3
24 St
Westgate Dr
Land O' Lakes Dr
24 Ave
25 Ave
23 Ave
22 Ave
21A Ave
21 Ave
Waterfront
Landing
24 St
23 Ave
23 Ave
30 St
30 St
Crowsnest Highway
Stormwater Management Plan
West Coaldale ASP Ammendment 2022
Highway 3
24 St
Westgate Dr
Westgate Dr
Westgate Cres
Westgate Cres
Land O' Lakes Dr
21A Ave
25 St
21 Ave
21 Ave
Waterfront
Landing
24 St
23 Ave
23 Ave
30 St
30 St
Crowsnest Highway
FH
PROPOSED
DEVELOPMENT
FUTURE
COMMERCIAL
AREA '10'
SWMF
Area '4'
13.38 ha
Area '7'
4.22 ha
Area '3'
7.48 ha
Area '1'
4.21 ha
Area '5'
1.77 ha
Area '2'
3.67 ha
1.81 ha
Area '9'
1.37 ha
Area '6'
1.47 ha
Area '8'
3.90 ha
1:5 YEAR PRE-DEVELOPMENT
FLOW 104 LPS
EMERGENCY OVERLAND
FLOW ROUTE
AREA PONDING AT
SPILL ELEVATIONS
LEGEND
STORM MANHOLE AND PIPE
AREA '1'
EXISTING UTILITIES
STORM MANHOLE AND PIPE
FUTURE UTILITIES
SUB-CATCHMENTS
AREA '2'
AREA '3'
AREA '4'
AREA '5'
AREA '6'
AREA '7'
AREA '8'
AREA '9'
SWMF
CATCHMENT AREAS
FIGURE 14.0
Dec 01, 2022
229648CE
Emergency
Overland Flow From
Malloy 2 Pond