The Lake Simcoe watershed can be divided into eighteen subwatersheds or Hydrological units each drained by one or more tributaries of the lake. Subwatersheds can range in size from a few hectares to thousands of square miles and can cross political boundaries. For example, the Hewitt’s Creek subwatershed is the smallest subwatershed in the Lake Simcoe basin with an estimated area of 18.2 square kilometres, which contains portions of the City of Barrie and Township of Innisfil. The largest subwatershed unit is the Black River subwatershed at 377.6 square kilometres and it accommodates two Regional Municipalities, and four local municipalities. The dividing of the watershed into these smaller units allows for more detailed analysis and research including modelling the influence of land use on water quality and quantity.

Click on one of the Subwatersheds below to see more detailed information.

Print This Map