South Nation Watershed

Ontario's South Nation River drains 3,810 square kilometres from its headwaters just north of the St. Lawrence River near the city of Brockville, northward to its confluence with the Ottawa River near the community of Plantagenet. Approximately 60 per cent of the watershed is farmed, with a mix of livestock and cash crop production - mostly on flat, tile-drained fields. See map.

Two micro-watersheds within the South Nation Watershed have been chosen to evaluate the effectiveness of two BMPs designed to alleviate pollutant loads to water courses. One of these watersheds - the 480-hectare Philippe Blanchard Municipal Drain - flows into the Little Castor River, and the other - the 230-hectare Rolland Bisaillon Municipal Drain - flows directly into the South Nation River. Agricultural-based activities are typical of those found throughout Ontario.

Water quality in the South Nation Watershed is reduced in many areas, while agricultural and urban pressures continue to increase. Problems include direct cattle access to streams and rivers, and manure runoff from fields which can lead to fecal contamination of water resources. Research in this watershed has shown that tile drainage allows high levels of nutrients (nitrogen in particular) to rapidly move into streams and municipal drains.

South Nation Conservation is a community-based environmental organization dedicated to conserving, restoring, developing, and managing natural resources in the South Nation Watershed. They were involved in all aspects of the WEBs project, including landowner liaison.

Two BMPs were studied within the South Nation Watershed as follows:

  • Controlled tile drainage
  • Restricted cattle access

The Controlled Tile Drainage: Increasing yields and helping the environment fact sheet discusses methods and findings from the study of this BMP.

Date modified: