Progress is slow in reversing urban expansion trends
The urban boundary is the area within which the city provides municipal servicing (major roads, transit, sewer and water services) for residential development. It includes land on both sides of the Greenbelt. Land within the urban boundary has grown by 15% since 1986 and now totals 36,569 hectares. Approximately 29,650 ha of this land has been developed (urbanized).
The original intent for Ottawa's Greenbelt was to protect farms and scenic countryside from urban sprawl. Its ecological significance was only recognized later. The extent of urban development beyond the Greenbelt, and the additional costs of providing services across it, had not been anticipated during Greenbelt planning in the 1950s.
Between 2006 and 2014, the rate of urban growth was significantly higher outside the Greenbelt, accounting for almost twice the number of residential units as were built inside. In 2015, 93% of new units inside the Greenbelt were in apartment/condominium buildings, versus 5% outside.
Nonetheless, for each of the past four years, Ottawa has significantly exceeded its current Official Plan target to achieve 38% of growth through intensification. Effectively any increase in number of units built within the Greenbelt is counted towards this target. However, taking 2015 as an example, intensification accounted for only 16% of new units built outside the Greenbelt.
- City of Ottawa. Comprehensive Five Year Review of the Official Plan. 2009
- City of Ottawa. Program Manager, Research and Forecasting, Planning and Growth Management Department. 2016.
Tree cover within the urban boundary is below target levels
A Forest Strategy for Ottawa, promised in the 2006 Greenspace Master Plan, was to have included tree cover targets for specific areas of the city. In the absence of this Strategy, the only stated tree cover objective, as per Ottawa’s Official Plan, is 30%. The draft plan for the urban forest currently in development may offer more disaggregate targets.
In Ottawa, tree cover inside the Greenbelt is 20.7%, and only two of the four urban areas outside the Greenbelt meet the 30% objective. However, based on 2011 aerial photography and landcover data, tree cover in rural Ottawa is an estimated 37%. By comparison, Toronto’s tree cover target is 40%, and current cover is estimated to be 26.6%.
In the order of 25% of Ottawa’s trees are ash, so the ongoing infestation of emerald ash borer is significantly depleting tree cover. Along streets and in parks alone, the City has removed over 25,000 ash since 2009. The City also conducts extensive planting -- an average of over 100,000 trees per year since 2009. It will of course be many years before these contribute significantly to canopy cover.
The range of vital benefits provided by trees and forests is extensive, but from an ecological perspective, habitat is key. Due to fragmentation of Ottawa’s forest, only 3% is considered “deep” (interior) forest. Eastern Ontario bird species dependent on forest-interior include many warblers (e.g., the Blackburnian warbler, the black-throated blue warbler), thrushes (e.g., the wood thrush), and the pileated woodpecker.
- City of Ottawa. Greenspace Masterplan. 2006.
- Ottawa 2020. Environmental Strategy for the City of Ottawa. 2003.
- City of Ottawa. Official Plan - Environmental Protection. 2014
- City of Ottawa. Urban Forest and Tree Crown Mapping. derived from Spring 2015 digital colour aerial photography, 6 cm resolution
- City of Ottawa. Planning and Growth Management, personal correspondence. June 1, 2016
- City of Toronto, Parks, Forestry and Recreation. Sustaining and Expanding the Urban Forest. Toronto’s Strategic Forest Management Plan, 2012-2022. 2013.
- City of Ottawa. Forestry Services Branch. Personal correspondence, June 2016.
- City of Ottawa. Water Environment Strategy - Phase 1. 2014
Agriculture has a significant influence on Ottawa’s environment
Over 35% of Ottawa’s land area is in agriculture. Generally speaking, the eastern border of the Ottawa is most intensively cultivated. This is also the area of highest livestock intensity, though compared to 15 years ago there has been a decline in animal production and increase in crop production.
Current farming activities have an impact on future agricultural sustainability. For example soil loss through erosion reduces land productivity. Broader environmental impacts of agriculture include fragmentation and loss of wildlife habitat, GHG emissions, and water quality stressors.
Over 80% of Ottawa’s watercourses are in rural areas, and 88% of these run through private property. Only 1% of waterways in agricultural areas have the 30 m of naturalized buffer recommended for the protection of habitat and water quality. Total suspended solids are a significant agricultural pollutant in the region.
- City of Ottawa. Characterization of Ottawa Watersheds. 2011.
- City of Ottawa. Ottawa’s Rural Landscape. Ottawa Rural Clean Water Grant Program, 2011-2015 Program Review and Renewal Report. Accessed June 1, 2016.
- City of Ottawa. Planning and Growth Management Department. June 1, 2016.
- City of Ottawa. Ottawa Rural Clean Water Program. 2015.
- Econometric Research Limited and Harry Cumming & Associates. The Environmental Impacts of Regional Agriculture and Food Systems in Southern Ontario. August 2014.
Surface water quality varies greatly across Ottawa, but phosphorous is a widespread problem
The City tests for about 50 parameters on a monthly basis at over 130 stations on rivers, lakes and creeks in Ottawa. Based on the monitoring, phosphorus levels remain a concern in most of Ottawa’s watercourses. Too much phosphorus causes excessive plant growth and algae blooms, resulting in depleted oxygen and reduced capacity to support fish.
While individual parameters like phosphorous are important, the Water Quality Index (WQI) developed by the Canadian Council of Ministers of the Environment translates a broad suite of water quality data into a single score between 0 and 100. Scores below 64 indicate frequent or virtually continuous departure from natural or desirable conditions.
Based on 2012 to 2014 monitoring, Ottawa’s twenty lowest scoring stations rated between 37 and 50 on the WQI scale. These stations are primarily on small streams in the northeast quadrant of the City. These include several that drain directly to the Ottawa River and that have been of concern for many years.
Protecting small (headwater) streams is increasingly recognized as critical for many reasons, including the fact that many species depend on them at some point in their life history. Erosion control, proper manure storage, and green infrastructure approaches to slowing the flow of rainwater from surfaces into waterways are all important approaches, in addition to shoreline restoration. The Conservation Authorities and the City have some relevant initiatives and programs.
- City of Ottawa. Water Quality in Ottawa’s Rivers, Lakes and Streams. Accessed June 12, 2016.
- City of Ottawa. Water Environment Protection Program. Water Quality in Ottawa’s Rivers and Streams. May 2006.