Oak Ridges Moraine

The Oak Ridges Moraine is a geographic area in southern Ontario, Canada stretching from Milton to Rice Lake, near Peterborough. The Oak Ridges Moraine is one of the most significant landforms in southern Ontario. The moraine gets its name from its rolling hills and river valleys extending 160 km from the Niagara Escarpment to Rice Lake and was formed 12,000 years ago by advancing and retreating glaciers.

The moraine contains the headwaters of 65 rivers and streams and has a wide diversity of streams, woodlands, wetlands, kettle lakes, kettle bogs and significant flora and fauna. It is one of the last remaining continuous green corridors in southern Ontario: it is still 30 per cent forested and is one of the last refuges for forest birds in all of southern Ontario.

The moraine's sands and gravel deposits act like a giant rain barrel storing rain and snow melt. This underground water is then filtered through layers of sand and gravel (aquifers) and slowly released as cool fresh water to the 65 rivers and streams flowing north into Lakes Simcoe and Scugog and south into Lake Ontario. The greatest threat to the function of the moraine is inappropriate land uses on and below the surface of the moraine, particularly in headwater areas.

Use of the moraine is currently under dispute; environmental groups such as the Sierra Club maintain the area's delicate ecosystem is threatened by a planned housing development.

Attractive forests and hilly relief typical of the moraine are a magnet to developers looking for building opportunities near the densely populated greater Toronto area but many planners and residents see a need to preserve it from the negative aspects of urban sprawl. Recent legislation has provided a beginning to this process.