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[[File:Anatomy of a green street.png|thumb|Anatomy of a green street (Source: Ann English)]]
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Rights of way (RoW) standards in Ontario vary by municipality, but generally there are seven typical ROW types:
ROW standards in Ontario vary by municipality, but generally there are seven typical ROW types:
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{{TOClimit|2}}
 
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This article discusses the characteristics, opportunities, constraints, and examples for each of these road types. This guidance is not intended to be prohibitive of other LID options, but rather to help reduce the number of LID options in the preliminary phases of screening and to alert the designer to LID opportunities unique to each road type. Adjacent land uses, traffic demands, utility locations, budget constraints and geological conditions will determine the most appropriate LID solution.
*Local residential road
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*Residential collector road
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*Local industrial road
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*Industrial collector road
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*Minor arterial
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*Major arterial road
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*High density commercial road
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  −
 
  −
The characteristics, LID opportunities and constraints, and examples are presented for each of these ROW types on the following pages. Typical LID options for each of these street types are offered. However, this guidance is not intended to be prohibitive of other LID options, but rather to help reduce the number of LID options in the preliminary phases of screening and alert the designer to LID opportunities unique to that road type. Other considerations such as adjacent landuses, traffic demands, utility locations, budget constrains and geological conditions will determine the most appropriate LID solution.
      
==Local residential road==
 
==Local residential road==
===Rural Cross-Section===
   
[[File:Local Residential Road Rural Cross-section.png|thumb|Residential Road (Rural Cross-Section) and applicable LID options]]
 
[[File:Local Residential Road Rural Cross-section.png|thumb|Residential Road (Rural Cross-Section) and applicable LID options]]
Local residential streets are the most common street type. They serve as access to the residential lots within those areas created by, or bounded by, thoroughfares, arterials, collectors,and primary residential streets and other physical boundaries such as natural streams and railroads. Since the primary function is local vehicular access rather than intercommunity circulation, theses roads have low traffic volumes and mostly lightweight vehicular traffic, but they must accommodate the rapid access needs of emergency vehicles. Other characteristics specific to the residential rural cross section include:
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Local residential streets are the most common street type. They serve as access to the residential lots within areas created by, or bounded by, thoroughfares, arterials, collectors, primary residential streets and other physical boundaries, e.g. natural streams and railroads. Since their primary function is local vehicular access rather than inter-community circulation, theses roads have low traffic volumes and serve mostly lightweight vehicular traffic, but they must accommodate the rapid access needs of emergency vehicles.  
 +
 
 +
===Rural cross-section===
 +
{{Textbox|1=Characteristics specific to the residential rural cross section include:
 
*Shoulders are grassed, gravel, or bare soil from winter maintenance, pedestrians and street side parking
 
*Shoulders are grassed, gravel, or bare soil from winter maintenance, pedestrians and street side parking
 
*Side drainage ditches are often narrow, poorly graded,and can be difficult for homeowners to maintain
 
*Side drainage ditches are often narrow, poorly graded,and can be difficult for homeowners to maintain
*Utilities are often in separate trenches rather than a combined utility trench
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*Utilities are often in separate trenches rather than a combined utility trench}}
 +
{| class="wikitable sortable" style="text-align: center;"
 +
|+ LID options for rural residential road (rural cross section)<br>
 +
(** = Common, * = Possible, o = Unusual)
 +
! RoW Construction Type
 +
! [[Stormwater planters]]
 +
! [[Curb extensions]]
 +
! Boulevard [[Bioretention|bioretention]]
 +
! [[Bioswales|Bioswales]]
 +
! [[Enhanced swales]]
 +
! [[Exfiltration trenches]]
 +
! [[Permeable pavements]]
 +
! Prefabricated modules
 +
|-
 +
|style="text-align: left;" |Resurfacing || o || o || * ||** || ** || * || * || o
 +
|-
 +
|style="text-align: left;" |Reconstruction || o ||o || * ||** || ** ||* || * || o
 +
|}
   −
===Typical opportunities for rural cross section===
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{|class= wikitable "style=text-align: center;"
'''Within the roadway:'''
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|+ Opportunities for rural residential
*Use of permeable pavement within the roadway is not economical when there are adjacent swales to filter and infiltrate runoff
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|-
 
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| Within the roadway
'''Within the boulevard:'''
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| Within the boulevard
*Bioswales or the use of perforated pipes beneath grass swales can reduce the nuisance problems associated with conventional swales like standing surface water and steep slopes
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|-
 +
|
 +
*Use of [[permeable pavements]] within the roadway is not economical when there are adjacent [[swales]] to filter and infiltrate runoff
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|
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*[[Bioswales]] or the use of [[perforated pipes]] beneath grass swales can reduce the nuisance problems associated with conventional swales like standing surface water and steep slopes
 
*Permeable pavement systems can be used to stabilize and improve degraded shoulders
 
*Permeable pavement systems can be used to stabilize and improve degraded shoulders
*Converting degraded ditches to enhanced grass swales is the simplest LID improvement to make to residential rural cross-section roads. Driveway culverts can be slightly raised to provide storage and encourage infiltration
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*Converting degraded ditches to [[enhanced grass swales]] is the simplest LID improvement for residential rural cross-section roads. Driveway culverts can be slightly raised to provide storage and encourage infiltration.
 +
|}
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===Urban Cross-Section===
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===Urban cross-section===
 
[[File:Local Residential Road Urban Cross-section.png|thumb|Local residential road (urban cross-section) and applicable LID options]]
 
[[File:Local Residential Road Urban Cross-section.png|thumb|Local residential road (urban cross-section) and applicable LID options]]
Characteristics specific to the urban cross section include:
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{{Textbox|1= Characteristics specific to the urban cross section include:
 
*Parking zones are often underused
 
*Parking zones are often underused
 
*Residential boulevard space is the easiest to modify and use for stormwater management compared to other street types
 
*Residential boulevard space is the easiest to modify and use for stormwater management compared to other street types
*Utility lines may be in separate or shared trenches  
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*Utility lines may be in separate or shared trenches}}
 
+
{| class="wikitable sortable" style="text-align: center;"
===Typical LID opportunities===
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|+ LID options for local residential road (urban cross section)  <br>
'''Within the roadway:'''
+
(** = Common, * = Possible, o = Unusual)
*Curb extension bioretention is a good method for calming traffic and using underutilized parking zones
+
! RoW Construction Type
*Due to low speeds and low traffic, permeable pavement can be used for the roadway from curb to curb
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! [[Stormwater planters]]
 +
! [[Curb extensions]]
 +
! Boulevard [[Bioretention|bioretention]]
 +
! [[Bioswales|Bioswale]]
 +
! [[Enhanced swales]]
 +
! [[Exfiltration trenches]]
 +
! [[Permeable pavements]] (sidewalk)
 +
! Prefabricated modules
 +
|-
 +
|style="text-align: left;" |Rural to Urban Reconstruction|| o || * ||** ||* || * ||** ||** || o
 +
|-
 +
|style="text-align: left;" |Resurfacing || o || ** ||** ||* || * ||** || * || o
 +
|-
 +
|style="text-align: left;" |Reconstruction || o ||** ||** ||* || * ||** || ** || o
 +
|-
 +
|style="text-align: left;" |Reduction || o || * || ** ||* || * ||** || o || o
 +
|}
   −
'''Within the boulevard:'''
+
{|class="wikitable"
*Boulevard bioretention can be easily incorporated into a rural to urban upgrade by allowing for stormwater treatment within the boulevard space
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|+ Opportunities for urban residential
 +
|-
 +
| Within the roadway
 +
| Within the boulevard
 +
|-
 +
|
 +
*[[Curb extensions]] are a good method for calming traffic and using underutilized parking zones
 +
*Due to low speeds and low traffic, permeable pavement can be used from curb to curb
 +
|
 +
*Boulevard [[bioretention]] can be easily incorporated into a rural-to-urban upgrade by allowing for stormwater treatment within the boulevard space
 +
|}
    
==Residential collector road==
 
==Residential collector road==
 
[[File:Residential_Collector_Cross_Section.png|thumb|Cross section of a residential collector road]]
 
[[File:Residential_Collector_Cross_Section.png|thumb|Cross section of a residential collector road]]
The function of these streets is to act as connectors between residential neighborhoods and other collectors and arterials. The character of these streets can vary widely from completely residential to pockets of commercial or mixed use land uses.
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These streets act as connectors between residential neighborhoods and other collectors and arterials. The character of these streets can vary widely, from completely residential to mixed-use to commercial.
Other characteristics include:
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{{Textbox|1=Characteristics include:
 
*Moderate to high traffic volumes, average daily traffic 1500 to 3000 vehicles
 
*Moderate to high traffic volumes, average daily traffic 1500 to 3000 vehicles
*Street parking is atypical unless there are adjacent mixed uses.
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*Street parking is atypical unless there are adjacent mixed use areas
*Often have multi-modal use, transit, pedestrian, and cyclists
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*Often have multi-modal use: transit, pedestrian, cyclists
*Institutions such as schools, recreational facilities, and churches are often located along collectors
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*Institutions such as schools, recreational facilities, and churches are often located along collectors}}
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===Typical LID opportunities===
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{| class="wikitable sortable" style="text-align: center;"
'''Within the roadway:'''
+
|+ LID options for residential collector road  <br>
*Permeable pavement should be avoided for high traffic travel lanes, but they are an option for parking lanes
+
(** = Common, * = Possible, o = Unusual)
and sidewalk. However, permeable pavers are susceptible to clogging if receiving runoff drainage from adjoining asphalt roadway. Pervious concrete or porous asphalt are options for bike lanes.
+
! RoW Construction Type
*Perforated pipes are suitable for collectors with very limited space and particularly where there is no routine landscaping maintenance. However, adequate pretreatment such as grass swales, extended sump catchbasins, or prefabricated units must be provided.
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! [[Stormwater planters]]
 +
! [[Curb extensions]]
 +
! Boulevard [[Bioretention|bioretention]]
 +
! [[Bioswales|Bioswales]]
 +
! [[Enhanced swales]]
 +
! [[Exfiltration trenches]]
 +
! [[Permeable pavements]] (sidewalk)
 +
! Prefabricated modules
 +
|-
 +
|style="text-align: left;" |Rural Resurfacing|| o || o ||** ||** ||** || * || * || o
 +
|-
 +
|style="text-align: left;" |Rural Reconstruction || o || o ||** ||** || ** || * || * || o
 +
|-
 +
|style="text-align: left;" |Rural to Urban Reconstruction || o ||* ||** ||** || o ||** || ** || *
 +
|-
 +
|style="text-align: left;" |Urban Resurfacing || o || o || ** ||* || o ||* || ** || *
 +
|-
 +
|style="text-align: left;" |Urban Reconstruction || o || * || ** ||* || o ||** || ** || *
 +
|-
 +
|style="text-align: left;" |Urban Reduction || o || o || ** ||* || o ||** || o || *
 +
|}
 +
 
 +
{|class="wikitable"
 +
|+ Opportunities for residential collector cross section
 +
|-
 +
| Within the roadway
 +
| Within the boulevard
 +
|-
 +
|
 +
*[[Permeable pavements]] is an option for parking lanes and sidewalk. However, permeable pavers are susceptible to clogging if receiving runoff drainage from adjoining asphalt roadway. Avoid permeable pavement for high traffic travel lanes. Pervious concrete or porous asphalt are options for bike lanes.  
 +
*Perforated pipes are suitable for collectors with very limited space, particularly where there is no routine landscaping maintenance. However, adequate pretreatment such as grass swales, extended sump catchbasins, or prefabricated units must be provided.
 
*Curb extension bioretention is not a common practice for collectors, but they can be used in some cases to reduce pedestrian crossing distances at intersections
 
*Curb extension bioretention is not a common practice for collectors, but they can be used in some cases to reduce pedestrian crossing distances at intersections
 
+
|
'''Within the boulevard:'''
   
*Collectors with few driveway access points and continuous stretches of open boulevard space are good candidates for bioswales
 
*Collectors with few driveway access points and continuous stretches of open boulevard space are good candidates for bioswales
 
*Institutional uses along collectors offer opportunities for innovative LID solutions. Runoff can be treated within adjacent park space or on school properties where agreements have been made with school boards. These areas are also good opportunities for LID showcases or demonstrations.
 
*Institutional uses along collectors offer opportunities for innovative LID solutions. Runoff can be treated within adjacent park space or on school properties where agreements have been made with school boards. These areas are also good opportunities for LID showcases or demonstrations.
 +
|}
   −
==Local Industrial road==
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==Local industrial road==
 
[[File:Local_Industrial_Road_Cross_Section.png|thumb|LID options for the local industrial road]]
 
[[File:Local_Industrial_Road_Cross_Section.png|thumb|LID options for the local industrial road]]
The function of local industrial roads is to provide access to industry and other employment zones. The ability to provide access and easy movement for large vehicles are a primary design characteristic of these types of streets. They are two to three lanes and are not intended for through traffic. Other characteristics include:
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Local industrial roads provide access to industry and other employment zones. Providing access and easy movement for large vehicles are a primary design characteristic of these types of streets. They have two-to-three lanes and are not intended for through traffic.
*Traffic volumes may be low but the road must still be wide enough to accommodate large vehicle turning movements and have increased structural strength to support heavy loads
+
{{textbox|1=Characteristics include:
*To avoid interference with truck movements landscaping should be low, and trees should be high branching or setback from the roadway
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*Traffic volumes may be low, but the road must still be wide enough to accommodate large vehicle turning movements and have the structural strength to support heavy loads
*Boulevards are often wide allowing for swale or other landscape treatment options
+
*To avoid interference with truck movements, landscaping should be low, and trees should be high branching or setback from the roadway
 +
*Boulevards are often wide, allowing for swale or other landscape treatment options}}
 +
 
 +
{| class="wikitable sortable" style="text-align: center;"
 +
|+ LID options local industrial road  <br>
 +
(** = Common, * = Possible, o = Unusual)
 +
! RoW Construction Type
 +
! [[Stormwater planters]]
 +
! [[Curb extensions]]
 +
! Boulevard [[Bioretention|bioretention]]
 +
! [[Bioswales|Bioswales]]
 +
! [[Enhanced swales]]
 +
! [[Exfiltration trenches]]
 +
! [[Permeable pavements]] (sidewalk)
 +
! Prefabricated modules
 +
|-
 +
|style="text-align: left;" |Rural Resurfacing|| o || o ||* ||*||** || * || * || *
 +
|-
 +
|style="text-align: left;" |Rural Reconstruction || o|| o||*||*|| ** || * || * || *
 +
|-
 +
|style="text-align: left;" |Rural to Urban Reconstruction || o ||o||* ||* || o ||** || ** || **
 +
|-
 +
|style="text-align: left;" |Urban Resurfacing || o || o || * ||* || o ||* || * || **
 +
|-
 +
|style="text-align: left;" |Urban Reconstruction || o || o || * ||* || o ||** || ** || **
 +
|-
 +
|style="text-align: left;" |Urban Reduction || o || o || * ||* || o ||** || * || **
 +
|}
   −
===Typical LID opportunities===
+
{|class="wikitable"
'''Within the roadway:'''
+
|+ Opportunities for local industrial cross section
*Consideration should be given for wide turning trucks which may encroach on and degrade landscaping or road shoulders. Grid paver systems or widened gravel shoulders near turning areas can be used to accommodate occasional encroachment.
+
|-
'''Within the boulevard:'''
+
| Within the roadway
*LID options for local industrial roads will heavily depend on the adjacent industries. For example, bioswales and other filtering practices may clog quickly where heavy industry like concrete mixing plants will track sediment onto the roads. Grass swales with sediment traps or prefabricated oil/grit separators which can be cleaned out on a frequent routine basis would be appropriate. Conversely, bioswales and perforated pipe can work well in areas of light industrial and commercial landuses.
+
| Within the boulevard
 +
|-
 +
|
 +
*Consideration should be given for wide turning trucks which may encroach on and degrade landscaping or road shoulders. Use grid paver systems or widened gravel shoulders near turning areas to accommodate occasional encroachment.
 +
|
 +
*LID options for local industrial roads depend heavily on adjacent industries. For example, bioswales and other filtering practices may clog quickly where heavy industry like concrete mixing plants track sediment onto the roads.  
 +
*Grass swales with sediment traps or prefabricated oil/grit separators which can be cleaned out on a frequent routine basis would be appropriate.  
 +
*Bioswales and perforated pipe can work well in areas of light industrial and commercial land uses.
 +
|}
    
==Industrial collector road==
 
==Industrial collector road==
Line 83: Line 188:  
*High profile industry is often located along industrial collectors and a high quality corporate landscape treatment is expected
 
*High profile industry is often located along industrial collectors and a high quality corporate landscape treatment is expected
 
*To avoid interference with truck movements landscaping near roads should be low and trees should be high branching or setback from the roadway
 
*To avoid interference with truck movements landscaping near roads should be low and trees should be high branching or setback from the roadway
 +
 +
{| class="wikitable sortable" style="text-align: center;"
 +
|+ LID options industrial collector road  <br>
 +
(** = Common, * = Possible, o = Unusual)
 +
! RoW Construction Type
 +
! [[Stormwater planters]]
 +
! [[Curb extensions]]
 +
! Boulevard [[Bioretention|bioretention]]
 +
! [[Bioswales|Bioswales]]
 +
! [[Enhanced swales]]
 +
! [[Exfiltration trenches]]
 +
! [[Permeable pavements]]
 +
! Prefabricated modules
 +
|-
 +
|style="text-align: left;" |Rural Resurfacing|| o || o ||* ||*||** || * || * || *
 +
|-
 +
|style="text-align: left;" |Rural Reconstruction || o|| o||*||*|| ** || * || * || *
 +
|-
 +
|style="text-align: left;" |Rural to Urban Reconstruction || o ||o||* ||* || * ||** || * || **
 +
|-
 +
|style="text-align: left;" |Urban Resurfacing || o || o || * ||* || * ||* || * || **
 +
|-
 +
|style="text-align: left;" |Urban Reconstruction || o || o || * ||* || * ||** || * || **
 +
|-
 +
|style="text-align: left;" |Urban Reduction || o || o || * ||* || * ||** || * || **
 +
|}
    
===Typical LID opportunities===
 
===Typical LID opportunities===
Line 90: Line 221:  
'''Within the boulevard:'''
 
'''Within the boulevard:'''
 
*Broad enhanced grass swales with perforated pipe can take advantage of wide boulevard spaces
 
*Broad enhanced grass swales with perforated pipe can take advantage of wide boulevard spaces
*Any landscape based solutions must consider the landscaping expectations of adjacent properties both
+
*Any landscape-based solutions must consider the landscaping expectations of adjacent properties, with respect to both aesthetics and maintenance. Some areas will expect simple turf lawn frontage that can be easily maintained, while other higher-profile industrial
with respect to aesthetics and maintenance. Some areas will have an expectation for a simple turf lawn
+
areas will want distinctive, signature landscapes with decorative plantings and shrubs.
frontage that can be easily incorporated into their maintenance, while other higher profile industrial
  −
areas will want distinctive signature landscapes with decorative plantings and shrubs.
      
==Minor arterial==
 
==Minor arterial==
 
[[File:Minor_Arterial_Road_Cross_Section.png|thumb|LID options for the minor arterial road]]
 
[[File:Minor_Arterial_Road_Cross_Section.png|thumb|LID options for the minor arterial road]]
Minor arterial roads are automobile oriented roads intended to move high vehicle traffic volumes and are typically four lanes. Pedestrian and bicyclist accommodations are sometimes expected. Other common characteristics include:
+
Minor arterial roads are automobile-oriented, move high volumes ofvehicle traffic and are typically four lanes. Pedestrian and bicyclist accommodations are sometimes expected. Other common characteristics include:
*Boulevards are often wide but must accommodate sidewalks on both sides, street trees and splash pads
+
*Boulevards are often wide, but must accommodate street trees, splash pads and sidewalks on both sides
 
*May include narrow medians, but runoff is typically directed away from them to road sides
 
*May include narrow medians, but runoff is typically directed away from them to road sides
 +
 +
{| class="wikitable sortable" style="text-align: center;"
 +
|+ LID options for the minor arterial road  <br>
 +
(** = Common, * = Possible, o = Unusual)
 +
! ROW Construction Type
 +
! [[Stormwater planters]]
 +
! [[Curb extensions]]
 +
! Boulevard [[Bioretention|bioretention]]
 +
! [[Bioswales|Bioswales]]
 +
! [[Enhanced swales]]
 +
! [[Exfiltration trenches]]
 +
! [[Permeable pavements]]
 +
! Prefabricated modules
 +
|-
 +
|style="text-align: left;" |Rural Resurfacing|| o || o ||* ||*||** || * || * || *
 +
|-
 +
|style="text-align: left;" |Rural Reconstruction || o|| o||*||*|| ** || * || * || *
 +
|-
 +
|style="text-align: left;" |Rural to Urban Reconstruction || ** ||o||* ||* || o ||** || ** || **
 +
|-
 +
|style="text-align: left;" |Urban Resurfacing || o || o || * ||* || o ||* || * || **
 +
|-
 +
|style="text-align: left;" |Urban Reconstruction || ** || o || * ||* || o ||** || ** || **
 +
|-
 +
|style="text-align: left;" |Urban Reduction || ** || o || * ||* || o ||** || * || **
 +
|}
    
===Typical LID opportunities===
 
===Typical LID opportunities===
Line 105: Line 260:  
*Dedicated parking lanes or parking lay-bys can be converted to permeable pavers. The permeable parking lane can be designed to accept only the rainfall that falls on it or it can take runoff from up to two additional lanes.
 
*Dedicated parking lanes or parking lay-bys can be converted to permeable pavers. The permeable parking lane can be designed to accept only the rainfall that falls on it or it can take runoff from up to two additional lanes.
 
'''Within the boulevard:'''
 
'''Within the boulevard:'''
*Attractive bioretention planters and permeable paver sidewalks are appropriate for high density areas and where business districts expect an enhanced or signature streetscape.
+
*Attractive [[stormwater planters]] and [[permeable pavements|permeable pavement]] sidewalks are appropriate for high density areas and where business districts expect an enhanced or signature streetscape.
*Street trees can be supported with LID options by providing root volume space in bioretention practices or with sidewalk support systems. Permeable sidewalks allow air and moisture to reach tree roots which in turn reduces sidewalk buckling from roots pushing through the surface.
+
*Street [[trees]] can be supported with LID options by providing root volume space in [[bioretention]] practices or with sidewalk support systems. Permeable sidewalks allow air and moisture to reach tree roots, which in turn reduces sidewalk buckling from roots pushing through the surface.
    
==Major arterial road==
 
==Major arterial road==
 +
[[File:Major_Arterial_Cross_Section.png|thumb|text]]
 +
Major Arterials are broad, four to six lanes, with an emphasis on speed, high volume vehicle flow and little on pedestrian or bicycle accommodation. Other characteristics include:
 +
*Wide boulevards and large landscaped medians are common
 +
*Due to higher travel speeds, maintaining clear zones and sight distances is critical
 +
 +
{| class="wikitable sortable" style="text-align: center;"
 +
|+ LID options for the major arterial road  <br>
 +
(** = Common, * = Possible, o = Unusual)
 +
! ROW Construction Type
 +
! [[Stormwater planters]]
 +
! [[Curb extensions]]
 +
! Boulevard [[Bioretention|bioretention]]
 +
! [[Bioswales|Bioswales]]
 +
! [[Enhanced swales]]
 +
! [[Exfiltration trenches]]
 +
! [[Permeable pavements]]
 +
! Prefabricated modules
 +
|-
 +
|style="text-align: left;" |Rural Resurfacing|| o || o ||* ||*||** || * || * || *
 +
|-
 +
|style="text-align: left;" |Rural Reconstruction || o|| o||*||*|| ** || * || * || *
 +
|-
 +
|style="text-align: left;" |Rural to Urban Reconstruction || o ||o||* ||* || o ||** || ** || **
 +
|-
 +
|style="text-align: left;" |Urban Resurfacing || o || o || * ||* || o ||* || * || **
 +
|-
 +
|style="text-align: left;" |Urban Reconstruction || ** || o || * ||* || o ||** || ** || **
 +
|-
 +
|style="text-align: left;" |Urban Reduction || ** || o || * ||* || o ||** || * || **
 +
|}
 +
 +
===Typical LID opportunities===
 +
'''Within the roadway:'''
 +
*Where possible, replace unnecessarily paved areas such as medians or traffic islands with pervious areas. If road grading allows, convert these areas into treatment practices for surrounding impervious areas
 +
*If the road is double crowned, medians are an excellent place to treat arterial runoff with simply landscaped bioretention areas or bioswales
 +
*If road grades direct no runoff to the median, reducing the median width and increasing the boulevard space would open more area for stormwater treatment along the side of the roads where the runoff drains
 +
*Getting plants to survive may be difficult in narrow medians. Consider decorative permeable paver solution over simply covering them with impervious asphalt or concrete
 +
 +
'''Within the boulevard:'''
 +
*Bioretention planters are appropriate for high profile urban arterial roads, but they must be properly designed to handle flows from larger impervious areas and have easily cleaned pretreatment practices
 +
 +
==Main streets==
 +
[[File:Main_Streets_Cross_Section.png|thumb|LID options for main streets]]
 +
Main streets are set in areas with high-density commercial, residential, and mixed use and are typically focal points of the community. The buildings have small to no setbacks and create a continuous wall along the street. They offer an opportunity to incorporate beautifying green infrastructure, but they are also a challenge for designers owing to the multiple demands of street parking, street trees, business access, above and below ground utilities, pedestrian accommodations and vehicle movement. Depending on age and prominence, these streets may have been reconstructed multiple times and have infrastructure legacy issues like abandoned utility lines. Other characteristics include:
 +
*Street parking is typical, may have frequent turn over and is necessary for local business.
 +
*ROW dimensions will vary greatly depending on the age of the community.
 +
 +
{| class="wikitable sortable" style="text-align: center;"
 +
|+ LID options for main streets  <br>
 +
(** = Common, * = Possible, o = Unusual)
 +
! ROW Construction Type
 +
! [[Stormwater planters]]
 +
! [[Curb extensions]]
 +
! Boulevard [[Bioretention|bioretention]]
 +
! [[Bioswales|Bioswales]]
 +
! [[Enhanced swales]]
 +
! [[Exfiltration trenches]]
 +
! [[Permeable pavements]]
 +
! Prefabricated modules
 +
|-
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|style="text-align: left;" |Urban Resurfacing|| o || o ||o ||o||o || o || * || **
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|-
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|style="text-align: left;" |Urban Reconstruction || **|| **||o||o|| o || ** || ** || **
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|-
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|style="text-align: left;" | Urban Reduction|| ** ||**||o ||o || o ||** || ** || **
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|}
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===Typical LID opportunities===
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Multifunctional LID practices are favored where there is a premium on space. Bioretention planters can serve to beautify the street and to treat stormwater. Permeable pavement serves as a treatment practice but is also a hardscape for parking and pedestrians.
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'''Within the roadway:'''
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*Curb extension bioretention can be used as a traffic calming feature and reduce pedestrian crossing distances.
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'''Within the boulevard:'''
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*Due to the high profile of these types of street, they are maintained on a frequent basis and provide the most appropriate setting for aesthetically pleasing bioretention features.
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*Street trees are high priorities for this road type and LID options should support or incorporate them by providing root volume space in bioretention practices or with sidewalk support systems.
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==Other design considerations==
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The previous sections presented the most common options based on road and construction types. The project team must use the information gathered through the [[Site conditions road right of ways|background review and field reconnaissance]], feedback gained from the public engagement, as well as from the LID practice Suitability & Considerations Comparison Table to determine the feasible and optimal LID options for the site. Below is a list of factors to be considered when choosing the type of practice and how it will be incorporated into the site:
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'''Relevant stormwater criteria –''' compliance with high level municipal and agency documents (i.e. Subwatershed study, master drainage plan).
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'''Site users –''' who are the users and how will they use the site in future (i.e. are pedestrians using this street to access other services such multi-use pathways, bus routes, commercial areas).
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'''Surrounding land use –''' schools, community centers, industrial, residential or commercial areas.
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'''Project support –''' are the local users likely to support the initiatives and become engaged in the project (renters vs. property owners).
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'''Mature vegetation –''' large trees can be a constraint particularly in municipalities with tree protection bylaws.
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'''Underground and overhead utilities –''' utility conflicts may eliminate an LID option but there are workaround solutions
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'''Accommodation of surface elements –''' location, sizing, and spacing of LID practices must consider surface elements such as light standard, transit shelters and fire hydrants. The structural support of these also must be considered, for example a light standard near bioretention may require a deeper base.
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'''Current or future transportation requirements -''' transportation planning initiatives can be integrate into the ROW retrofit design objectives to facilitate future projects.
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'''Existing aesthetic character of the site –''' neighborhoods with established gardens, mature trees, and professionally landscaped frontages may be more receptive to a higher landscape aesthetic of vegetated LID practices such as bioretention or bioswales.
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'''Existing maintenance protocols and equipment –''' how is the ROW currently maintained and can the same techniques be used after the LID practice is constructed.
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'''Impacts to local drinking water wells –''' consider if threats under Source Water Management Plans have been identified.
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'''Encroachment issues (residents encroaching within the ROW) –''' including fences, driveways, or other structures
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'''Traffic safety issues –''' are there reports or records of increased traffic issues. If so consider how the LID practice can be used to address the issues.
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'''Parking availability and access –''' where parking must be preserved, permeable pavement should be considered, but where parking is underused, then impervious area can be reduced with curb extensions or reduced street width.
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'''Additional benefit opportunities –''' are there other retrofit opportunities that can be incorporated into the retrofit such as park improvements, trail connections and educational signage potential.
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'''Existing municipal policies and by-laws –''' The existing policies and by-laws review should not be considered as barriers to the project, but instead should be considered in the context of points of discussion for the municipal project team during the implementation process. Undertaken in the context of a demonstration project, the existing by-laws and standards can be relaxed and reviewed within a controlled environment. With all the departments leads present, a demonstration project can be an opportune time to discuss and re-evaluate. Typical municipal codes, standards and bylaws
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to be investigated may include:
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==High density commercial road==
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*Noxious weed by-laws – can exclude native species and limit plant selection. Redefinition and re-evaluation of plants within these lists may be warranted.
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*Property standards by-laws – can prevent implementation of LID practices such as permeable pavements (gravel or turf stone driveways), bioretention or bioswales which incorporate temporary surface ponding.
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*Boulevard planting by-laws – can prevent implementation of LID practices such as bioswales due to plant type and height restrictions of planting along municipal ROW and boulevards.
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*Standing water by-laws – can prevent implementation of LID practices which incorporate temporary surface storage. The definition (or redefinition) of ‘standing water’ to allow for up to 48 hours of ponded water within LID practices may be warranted.
    
Go back to [[Screening LID Options]]
 
Go back to [[Screening LID Options]]
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[[Category: planning]]
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