Green Shores | Case Studies
Portage Road, Saanich, British Columbia
↪ Green Shores for Homes project
The riparian area was fully protected through a newly established covenant.
Project Overview
| Location: Portage Road, Saanich, British Columbia | Project area: 0.9 ha |
| Year completed: 2022 | Awards: NA |
| Shoreline length: 60.9 m | Shore type: Shoreline sediment is primarily silt, fine sand and organic materials |
| Green Shores rating achieved: GOLD | Total points: 68 |
Site Description
This shoreline segment of the Colquitz River lies on the Eastern side of the Portage Inlet and has tidal influence from the Gorge Waterway. The total property is comprised of two adjacent lots with a total area of 0.9 hectares. Shoreline riparian vegetation includes sedges, overhanging trees and shrubs such as Red Osier Dogwood. Small amounts of natural woody material are found on the silty banks. A Natural State Covenant Area has been established over the entire riparian area and to a depth from the natural boundary that exceeds the legal municipal requirement of 15 metres. This property is within the area important to migratory birds, designated as the Victoria Harbour Migratory Bird Sanctuary – Canada.ca.
Project Team and Affiliated Organizations
- Design Build General Contractor: Artificer Development Corporation
- Design Architect: Artificer Development Corporation
- Covenant Restoration: Susan Blundell
- Environmental Management Plan: Aqua-Tex Scientific Consulting Ltd.; WSP in Canada
- Native Plant Supplier: Novus Plants
Project Objectives
- Protect a well-established riparian area through creation of a Natural State Covenant Area, which continues to provide many benefits, including wildlife habitat and stabilization of the tidally influenced foreshore from potential erosion.
- Monitor and protect existing trees within the covenant area, and plant additional trees and native plants throughout the property while systematically managing invasives.
- Promote overall infiltration and management of surface run-off on site through the development of rain gardens and the use of permeable materials.
Work Plan
The property has been developed to maintain environmental integrity while allowing for new low-density construction. Vegetation has been protected in both the riparian buffer, and throughout the overall area through retention of existing healthy trees, planting with native species, and systematically removing invasives such as Himalayan Blackberry and ivy. Newly constructed homes were built with a setback that exceeded the Municipality of Saanich requirements, met Green Shores best practices for adaptation to sea level rise, and was particularly proactive given the option to build closer to the natural boundary. Rain gardens were established at different locations to collect and utilize roof run-off.
Aerial image of the newly established Natural State Covenant Area that spans the entire riparian area.
Description of how the project meets Green Shores principles
> Maintained/ Enhanced Habitat Function and Diversity
- The entire riparian area is being preserved. A Natural State Covenant has been registered over 2052m2 of the site, 1390 m2 of which is the riparian foreshore. The riparian buffer was enhanced for a total width along 100 percent of the shoreline, and to a depth that exceeds the 15-metre setback from the natural boundary required by the District of Saanich. Terrestrial habitat for birds, mammals, amphibians and reptiles is available in this buffer, and the retention of overhanging trees and shrubs provides benefits for the aquatic habitat.
- Rain gardens that have been installed adjacent to each home on the property provide additional aquatic and terrestrial habitat.
- Woody material retained along the shoreline provides habitat for wildlife and micro-habitat for vegetation.
- The implementation of the landscape maintenance plan with best practices for the environment (e.g., no use of synthetic chemicals) protects the integrity of both the terrestrial and aquatic areas.
> Preserved/Restored Shoreline Physical Processes
- The natural shoreline gradient is gradual and functions well through inter-tidal influence from the Portage Inlet. Retention of the riparian buffer provides more protection from higher water levels expected with sea level rise, more intense storm events and higher King tides.
- The retained woody material and established vegetation root systems support the natural movement of water and sediment along the shoreline while protecting the shoreline from erosion.
> Ecological Services Provided
- Expanded riparian function including shoreline stabilization, erosion control and filtration.
- Comprehensive site maintenance of overland run-off through constructed rain gardens and treatment of road run-off.
- Habitat creation from covenant establishment over the entire riparian buffer, native plant installation and woody material placement.
- Increased groundwater recharge to sub-surface aquifers through creation of multiple rain gardens designed to allow roof run-off to infiltrate in-situ soils.
> Additional Notes
- The application of Green Shores best practices for both the shoreline and upland at this location showcases how Green Shores principles can protect environmental values while allowing for development of infrastructure, particularly in an urban environment. The property is now significantly more resilient to potential impacts from climate change including more intensive weather events and sea level rise. It can serve as a great example of how nature-based solutions reduce risks for the homeowner and enhance property values.
