Nitrogen is an essential nutrient for the survival and growth of most living organisms.  Nitrogen gas is a large constituent of the atmosphere, making up approximately 80% of the air, but this form is inaccessible by most plants. Certain bacteria in soils have the ability to ‘fix’ naturally-occurring nitrogen from the atmosphere, which converts it to a usable form for the plants, it can also be fixed by lightning or through an industrial process which makes nitrogen fertilizers. Nitrogen is generally the limiting nutrient in terrestrial ecosystems, and is applied to fields through use of fertilizers and manure. Once in the soil, the nitrogen will be used by the crops, leached down, or emitted into the atmosphere. In the soil, ammonium (NH4+) or ammonia (NH3) is broken down by bacteria through nitrification in which it is converted first to nitrite and then to nitrate. 

Both nitrites (NO2-) and nitrates (NO3-) are highly soluble forms of nitrogen and thus are transported easily in water and do not attach to the soil. Nitrite is more toxic than nitrate but since the processes changing nitrite to nitrate happen quickly it is not generally found in large quantities. Though less toxic, high concentrations of nitrate in aquatic systems can have both acute and chronic lethal effects on amphibians as well as any species which prey on amphibians, such as fish. NH3 which has not been converted through nitrification can also have harmful effects on aquatic organisms. The major sources of NH3 in aquatic systems are wastewater and treatment plants. 

Canada is the second most water-rich of the OECD countries with 85,516 cubic metres of renewable freshwater per capita. However, 60% of this water is unavailable to 85% of the population as it flows north away from the city centres. With this in mind, Canada still ranks fourth. It is also the second highest water user at 1,441 cubic metres per capita. Even with high water usage, only 2% of the renewable freshwater resources are withdrawn from the source annually. Ninety-six percent of the water comes from surface sources such as lakes and rivers and the remaining 4% is taken from groundwater sources. From 1985 to 1995 the amount of water withdrawn from these sources annually dropped 0.4% and in 1996 it was estimated that 20% of the water went to domestic and household use, 69% to industrial and commercial uses, and 12% to irrigation and agriculture.

The breakdown of land and water surface area is shown below. Canada and Ontario have 8.9 and 14.7% respectively of their total area in freshwater, which is made up of lakes, ponds, rivers, streams, wetlands, swamps, and sloughs (CWF [1]). The Lake Simcoe and Nottawasaga Valley Watersheds have 33 (lake and wetlands only) and 23% respectively of their land area under water (EC).

Canada has a large supply of freshwater but is also one of the highest users of water. Even though overall the country has vast amounts, the distribution is uneven and access is limited in some areas. Challenges moving forward for the country, the province, and these watersheds include an increasing demand as the population grows and combating pollution while protecting the freshwater sources.

Unless otherwise noted, data is sourced from CWF [2]

Part 4 of a 4-part series on watersheds

This watershed is divided into three parts, Lake Couchiching, Severn Sound, and Georgian Bay Coast. The first section is positioned at the southeastern tip of the area around the 34 square kilometre Lake Couchiching which is at the top of Lake Simcoe (EC). Severn Sound is comprised of a 130 square kilometre series of bays on south-eastern Georgian Bay (EC). The final part of this watershed is the section of coastline between Port Severn and where the French River enters Georgian Bay.

The townships of Severn, Tay, and Tiny, the Towns of Midland and Penetanguishene, and the City of Orillia in Simcoe County and areas along the coast in the Districts of Muskoka and Parry Sound are all represented in this watershed.

This watershed supports a large recreational and tourist industry. Severn Sound has a permanent population of 110,000 that swells seasonally to 300,000 (EC). The cottage industry is causing development along the coasts as it grows and this could become a concern as the integrity of the coastline is changed. Agriculture also has a presence; in Severn Sound there are about 900 farms on approximately 270 square kilometres (SSEA [1]).

Severn Sound was identified as an ‘Area of Concern’ by Environment Canada due to degraded water quality and environment health. Through phosphorus control, habitat restoration and enhancement, pollution prevention, planning, environment monitoring, and public education, it was removed from the list in 2003 (SSEA [2]).

Part 1 of a 4-part series on watersheds

A watershed is the land area from which water is collected and drained into a body of water such as a stream, river, lake, or ocean. The size and shape is determined by geography; hills, moraines, and other tall features form the outskirts of a watershed as the water flows downhill. A larger watershed, such as one draining into a lake can be divided into subwatersheds based upon individual river systems. Several watersheds can be grouped together to form a single watershed for large bodies of water, such as the Great Lakes.

The boundaries of a watershed usually do not coincide with government boundaries. A watershed can then be half in one county and half in another if the county or municipal border is following a river or creek. This creates problems when working within the watershed as it is under two separate governing bodies. It’s common for a watershed to be impacted by the laws of several regions, townships, towns, and cities.

Water is always flowing somewhere, whether quickly or slowly. Issues that arise in an area at the top of a stream will travel down that stream to a river. The river will carry that issue down to a lake. In time, that issue can make its way into the ocean and could grow and change along the way. Any effort made to mitigate problems upstream or at the margins of a watershed will have an impact further down the waterway.

The HMGA-LSGBCUF project is working within three neighbouring watersheds: Lake Simcoe, Nottawasaga Valley, and South-Eastern Georgian Bay, as shown in the map below. Together they cover and influence a vast area of both land and water as well as impact the people who live within them.