The Lake Huron Centre For Coastal Conservation
Advocating Wise Stewardship of Lake Huron's Coastal Ecosystems
2.0 - Overview of the Southeastern Coast of Lake Huron
The southeastern coast of Lake Huron between Sauble Beach and Sarnia is comprised of five primary watersheds that outlet into the lake. These include the Sauble River outletting at Sauble Beach, Saugeen River outletting at Southampton, Maitland emptying at Goderich, the Bayfield River flowing out at Bayfield and the Ausable River at Port Franks. Secondary watersheds include the Penetangore, Pine, Eighteen Mile and Nine Mile rivers. Tertiary watersheds include numerous creeks, gullies and drains flowing directly into Lake Huron.
Agriculture is the predominant land use throughout this region. Huron County, within the study area, has been identified as the most agriculturally productive county in Ontario. As part of the Maitland watershed, it also produces the greatest amount of manure in Canada at 7610 kilograms per hectare, with the Saugeen and eastern Lake Huron area (comprising the Penetangore and Pine River systems) within the top 10. The Maitland watershed also had the highest estimated concentrations
Forest cover within the main watersheds is generally highest to the north and lowest to the south. The Saugeen watershed, for example, has a 30% forest cover overall, but the forest cover is greatest in the northern and eastern parts of the watershed and lower to the south and west. The Pine River watershed in the southwest corner of the Saugeen watershed has a total forest cover of only 6.6% (Smith, 2003). The Maitland watershed has a total forest cover of 15.5% (MWP, 2002). Moving south, forest cover continues to decrease, while the land used for agriculture increases.
Urban centres are scattered throughout these watersheds, but a concentration of urban and semi-urban (cottage) development occurs along the shoreline with the largest centres including the Town of South Bruce Peninsula (population 8,090), Saugeen Shores (pop. 12,500), Kincardine (pop. 12,000), Goderich (pop. 7500), Town of Bluewater (pop. 6920), Town of South Huron (pop. 10,020), municipality of Lambton Shores (pop. 11,000), Point Edward (pop. 2101), and Sarnia (pop. 70, 876). Between these centres are semi-urbanized strip developments along the coast.
Development has been on an upward trend along the lakeshore over the past three decades. In a study of the Lake Huron coast, from Southampton to Point Clark, rapid urban and rural residential growth was attributed to a loss in the Huron Fringe forest cover from 58% in 1954 to 46% in 1990, although this figure does not reflect the amount of development in the understory. In the time period between 1954 and 1990, development increased from 8% to 17% of the total land use within the Huron Fringe in southern Bruce County (Lawrence and Nelson, 1992).
All of the coastal communities in the study area have an inextricable economic connection with Lake Huron. Area beaches are focal points for tourists and recreationists. For example, Grand Bend’s 0.8 kilometre of beach attracts an average of 5-8,000 users per day with weekend numbers rising from 20,000 to 25,000 per day. It has been estimated that “on beach” there may be 10,000 to 15,000 at any moment.
Pinery Provincial Park, to the south of Grand Bend, receives 8-10,000 bathers on peak holiday weekends, equal to approximately 1.25 bathers per metre of beach (ABCA, 1992). Similar numbers are prevalent at other public beaches in the study area.
Port Elgin attracts an estimated 25,000 during a peak weekend, with a substantial number of these people believed to be using the beach (Benge, 2003). In 2002, Sauble Beach attracted an estimated 2,570,000 person-visits in July and August (Town of South Bruce Peninsula, 2003). In Lambton County, despite the fact that most beaches are private, some of the private beaches are reportedly more heavily utilized than the public beaches in the area (SCRCA, 1991).
The physiography of Lake Huron’s coast has been shaped by a succession of post-glacial lakes, most notably Lakes Algonquin, Nipissing and Algoma, which formed what is known as the Huron Fringe. The Huron Fringe is defined as the narrow fringe of land along Lake Huron from Sarnia to Tobermory that is distinct from the clay plain adjacent and above it. It is comprised primarily of post-glacial lake deposits of sand dunes and gravel bars (Chapman and Putnam, 1973).
These relic shorelines and beach deposits are evident north of Point Clark and south of Grand Bend. The large expanses of sand deposits have given rise to an extensive cottage industry in these areas. These relatively flat, well drained sandy soils with a shallow water table provide optimum conditions for the transport of nitrate and bacteria to groundwater, and in turn, enhance the preservation of nitrate once it reaches the groundwater (McLellan, 2000).
Between Point Clark and Grand Bend the shoreline is composed of high clay till bluffs, reaching their highest point (25 metres) at Goderich. Occupying an area of about 1500 square kilometres along the eastern shore of Huron, the land slopes gently westward between the Wyoming moraine and the Algonquin bluff. This is known as the Huron Slope and is comprised primarily of the clay dominant St. Joseph Till. As water drains towards the lake a large 20 to 25 metre hydraulic head develops as the water reaches the shore bluff. Consequently, over 150 deep ravines have been incised into the till between Point Clark and Grand bend, creating direct drainage conduits to the lake. The heavy clay soils, typical of St. Josephs Till, can result in greater transport of nutrients (nitrate and phosphorous) and microbes (bacteria and protozoa) to surface water (McLellan, 2000).
The predominant wave direction on Lake Huron is from the northwest (Reinders, 1989). This sets up an alongshore current that moves nearshore sediments, on a net basis, from north to south. During summer months, when winds and waves tend to come from the southwest, the alongshore current can move sediments northward. Alongshore currents and the resulting sediment movement will have an influence on the movement of pollutants entering the nearshore waters of the lake, particularly those pollutants that become attached to sediment particles and move along the shoreline with the longshore drift. These alongshore currents can also form barrier beaches across the mouths of creeks and small watercourses causing a temporary stagnation of the estuary. Contaminants and algae blooms can accumulate in these areas until a rainfall event can breach the barrier and flush the estuary. These stillwater areas are an attraction to young children, particularly when high wave conditions make swimming in the lake undesirable. When flushing does occur, it sends a pulse of contaminants and other material into the lake.
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The Lake Huron Centre for Coastal Conservation P.O. Box 178, Blyth, Ontario, Canada N0M 1H0 Phone: (519) 523-4478 Email: coastalcentre@lakehuron.on.ca |
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