Land Use and Ecology

In 2016, 81% of the land within the urban boundary had been developed, a 15% increase since 1986.  There were 6,427 residential unit permits issued in the city of Ottawa in 2016, a 29.3% increase from 2015. Of these permits, a total of 5,019 housing starts were recorded in 2016, 68.4% of which were outside the Greenbelt.  Over the past decade it has been typical for there to be roughly twice as many housing starts outside the Greenbelt than inside, with the exception of 2015 when the split was approximately down the middle, with 47.5% of housing starts being inside the Greenbelt.

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.

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.

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.