8.0 Green Street Designs

Kanata Drive, Ottawa

The “Green Streets” concept is expressed in the City’s Greenspace Master Plan (2006). Green Streets are defined by their attractive, tree-lined open space character, and by their emphasis on environmental quality. They often connect components of Ottawa’s Greenspace Network such as parks, open spaces, natural areas and stormwater management facilities, as well as schools, civic buildings, workplaces, and other community destinations. They place an emphasis on creating comfortable and convenient facilities for pedestrians and cyclists, and they may also be important transit routes.

As the name implies, Green Streets are inherently very green, with an emphasis on trees, shrubs, sod, and plantings. Green living materials bring a myriad of cumulative benefits such as: temperature amelioration, energy use reduction, shading and UV protection, wind control, soil moisture infiltration, soil compaction avoidance, erosion management, air quality, oxygen production, CO₂ reduction, storm water retention, pollution reduction, noise abatement, glare reduction, habitat creation, visual environment improvement, and property value appreciation.

Green streets are typically located in the Urban Area and Villages and are identified in plans such as the Greenspace Master Plan, Community Design Plans and Secondary Plans. In plans that predated the 2006 Greenspace Master Plan, and use of the “green streets” term in the City of Ottawa, there are roads that have been highlighted that fulfill green street functions noted above. A higher standard of design and construction may be needed to fulfill the green street functions especially in designated areas of higher design standard such as Town Centres and the Central Area where:

• roads that have intentionally narrow rights-of-way protection;
• ROWs are constrained by existing development; and,
• there is competition for space among roadway elements.

While all streets should reflect Green Street characteristics, those that are identified or designated in plans to fulfill specific Green Street roles should exhibit exemplary design.

1. Identify “priority” Green Streets in Community Design Plans and Secondary Plans that have the greatest potential to connect major elements of the City’s Greenspace Network.
2. Provide additional opportunities for street trees, urban forest, pedestrian amenities and groundwater recharge along designated Green Streets. Use such means as enhancing the amount of area dedicated to the boulevard, placing priority on the creation of landscaped space when coordinating above and below ground utilities, managing surface water to enhance natural infiltration (see above), and locating the roadway off-centre in the ROW.
3. Create opportunities for shrub, ground cover and other plants in addition to street trees to emphasize the attractive green nature of the street, enhance environmental quality, and to reinforce its function as a premiere open space component of the City.
4. Design Green Streets using sustainable infrastructure innovations (such as those outlined in Section 4.2), and use these streets as pilot projects where appropriate.
5. Coordinate landscape improvements on lands adjacent to designated Green Street corridors with landscape elements in the corridor to reinforce the green character of the corridor.
6. Give priority to pedestrian, cycling and road edge functions along a designated Green Street corridor through such means as minimizing vehicular lane widths, limiting on-road parking, and coordinating services into shared trenches.
7. Create the opportunity for Green Streets to be highly utilized transit routes, thereby bolstering the street’s many environmental benefits. Integrate transit priority measures along the street and enhance the quality of transit stops with shelters and generous landscaping.
8. When multi-use pathways connections are identified in the road corridor to connect key segments of the pathway network, design the pathway for continuity and safety. Locate the pathway to minimize the frequency of driveways, provide sufficient lateral safety clearances, and locate the pathway on the side of the road that would minimize the need to cross the road.
9. Where a Green Street provides a strategic link in the City’s Cycling Network, enhance cycling priority within the road corridor. Consider a range of cycling priority measures and dedicated cycling facilities such as: signed shared use lanes, dedicated cycling lanes, off-road pathways, traffic signal priority or other measures.

Green Streets will require location-specific designs. Choices will vary depending on adjacent greenspace features, path and cycling designations, on-road parking requirements, and drainage possibilities. The requirements range from 26m to 30m (see Table 8-1).

Lakepointe Drive, Ottawa

To fulfill “Green Street” functions, a road may require more space allocated to the road edge or medians. Allocating more space to accommodate green street elements can be accomplished by:

• widening of the road edge or median areas;
• narrowing the road surface through a road diet approach, such as the elimination of on-street parking allocation;
• establishing deeper front yard setbacks and coordinating the design of green street elements on adjacent private lands; and/or,
• making one road edge wider than the other to create sufficient room for green street elements, with roadway surface located off-centre in the ROW.

Green Streets should be identified in plans, and a wider ROW protected to accommodate their additional components. A sufficiently wide ROW can typically be secured by providing a road edge “supplement” in the range of 2.0 to 3.5m along each side of roads in Urban Areas and Villages. This assumes the range of “standard” roadway components such as demonstrated in Appendix A, which typically consume between 11.0 and 13.5m of the ROW. The resulting road edge and ROW widths are presented on Table 8-1.

There are many possible designs for Green Streets. The designs would vary on a case by case basis, and some may even require road edge widths greater than 9.5m. This may include instances where innovative road edge drainage treatments are desired (such as bioswales), when 3.0m multi-use pathways are planned, or when there are few opportunity for green features on adjacent lands. In some cases, wide (5.0m+) green medians may be desired. In other cases, an enhanced Green Street treatment may be pursued on only one widened road edge. However, in most cases, appropriate Green Street designs for Collector roads in the Urban Area and Villages should be accommodated in ROWs of 30m or less.