City of Pickering Official Plan- Edition 6

Pickering’s Natural Setting
Five times the area was hidden by ice. During the last
glacial period, which ended about 12,500 years ago, two
separate ice sheets covered the land, one centred on
Lake Ontario, the other further to the north. In between
the two sheets was a moraine (the “Oak Ridges Moraine”),
shaped by the accumulation of debris and material trapped
in the ice. The moraine lies at Pickering’s northern
boundary, and is the source of many of the City’s streams.
As the southern ice sheet retreated, a much larger lake,
known as Lake Iroquois, formed in the Lake Ontario
basin. Remnants of the shoreline of Lake Iroquois can still
be seen today across central Pickering. When the ice jam
in the St. Lawrence Valley finally melted, Lake Iroquois
receded to form present day Lake Ontario.
Meanwhile, the streams flowing out of the Oak Ridges
Moraine and the old shoreline began to cut their valleys.
Eventually, portions of six major watersheds traversed the
City (the Rouge, Petticoat, Frenchman’s Bay, Duffins,
Carruther’s, and Lynde systems). Pickering’s landscape as
we know it today, is the product of many years of geologic
evolution, and a much briefer period of human settlement.
Early Settlement
Evidence has been found of native occupation dating to at
least 4,000 years ago, although it is believed that people
lived in the area much earlier than that (possibly soon after
the ice sheets receded). In the mid-seventeenth century,
the Huron were driven from the region by the Five
Nations Iroquois who established a number of villages.
One they called “Ganatsekwyagon.” It was located on the
east bank of the Rouge River.
The Oak Ridges Moraine is
a prominent east-west ridge
of land spanning about 160
kilometers (100 miles) from
the Niagara Escarpment to
east of Cobourg. It
contains some of the most
scenic landscapes of
southern Ontario, and is of
great ecological importance
to the health of people,
plants and animals in the
area.
Pickering lies in a larger
geographic area known as
the “Greater Toronto
Bioregion”, a region that
shares similar physical and
biological features. This
wedge-shaped area is
defined by the Niagara
Escarpment to the west, the
Oak Ridges Moraine to the
north and east, and the
Lake Ontario shoreline to
the south.
PICKERING OFFICIAL PLAN EDITION 6: Introduction 3