Severn Sound is a group of bays covering an area of approximately 130 km² and is located in southeastern Georgian Bay, Lake Huron. The immediate watershed of the Sound covers an area of approximately 1000 km². The contact between the Precambrian shield and the sedimentary bedrock with varying overburden runs down the middle of the Sound. The basin is a complex of sheltered to exposed bays ranging from 2 to 4 m deep in the eastern end to a 43 m deep basin off the northern end of Beausoleil Island where the Sound meets Georgian Bay.
The Severn Sound watershed encompasses a combination of small urban and rural areas with a permanent population of approximately 110,000 people and a seasonal population of 300,000 people. The small urban areas are served by nine municipal sewage plants and extensive areas on private sewage systems. Municipal water supplies include thirty two groundwater systems and two surface water systems.
The rural area consists of approximately 900 farming operations, of which about one third are livestock operations with more than 10 animals (Source: SSEA Agricultural Survey, 2000/01). Crop land, including pasture within the watershed totals an estimated 270 km². Map showing the Severn Sound Watershed Boundary, Environmental Association Member Municipalities and the SSEA Office Location. (1.2 mbs)