Fresh Water Environment
While the ocean environment has
conditioned every aspect of the Newfoundland and Labrador experience,
the province also has ample fresh water, the source of which is
abundant precipitation. More than 8% of the area of the province
is occupied by lakes, slightly greater than the average for
Canada, and as elsewhere water is also stored in the soil, either
close to the surface where it can be used by plants or deeper in
the rock as groundwater where it may be tapped by wells or
returned to the surface in springs.
||The province's many species of plants depend on water
that is stored in the surface of the soil.
Reproduced by permission of Trevor Bell.
Besides lakes and groundwater,
Newfoundland and Labrador also have many rivers. These rivers
show marked seasonal variations of flow. Throughout the province
peak flow occurs in late spring or early summer as the result of
spring run-off, when winter snow melts and runs over the surface
directly to the nearest stream. In the southern part of the
island peak flow occurs as early as April, but in central
Labrador it occurs as late as June. Some of the melting snow
infiltrates into the soil (if the soil is not frozen), moving
slowly downslope. Some of this soil water percolates deeper to
the groundwater, moving even more slowly.
|Stream located on Gros Morne Mountain trail, Gros Morne National
During late spring and early summer months, melting snow and precipitation create
peak water flow in rivers and streams.
Reproduced by permission of Wendy Churchill. Photo ©1990.
During the later part of the
summer and the fall streamflow is related to the balance between
is at a maximum in summer, when temperatures are higher and
plants are growing strongly. Farmers and gardeners know that the
soil is much drier in summer than in spring or fall; this is the
result of high evapotranspiration during the growing season and
means that very little of the rain that falls in summer reaches a
stream. Although stream flow is low during the later part of the
summer, streams rarely dry up completely. Lakes in a streams's
course store some of the spring run-off and help to maintain flow
as do springs fed by groundwater. Man-made reservoirs on dammed
streams function like natural lakes to reduce peak run-off and
maintain flow during the summer.
With the approach of fall
evapotranspiration decreases, and in the southern part of the
island precipitation increases. Soon the soil holds as much water
as it can (it is saturated), and the surplus reaches the streams
whose flow increases.
Illustration by Duleepa Wijayawardhana, 1998.
In winter, when temperatures fall
below freezing and precipitation falls as snow, no surface water
reaches the streams and flow decreases again. In Labrador and the
northern parts of the island where winters are long and severe,
this is the season of minimum streamflow. In central and southern
parts of the island, where precipitation can fall as rain during
the winter, the winter streamflow minimum is less marked than the
The volume of water discharged by
a stream is also affected by the size of the drainage basin. The
Waterford River, that runs through St. John's, the capital
of Newfoundland and Labrador, drains a small basin and the mean
rate of flow in April is less than 5 cubic metres per second. In
May, the month of maximum discharge in the Gander River (in
central Newfoundland), the mean discharge is more than 250 cubic
metres per second. The provincial record is held by the Churchill
River in central Labrador which discharges an average of almost
2000 cubic metres per second in June.
©1998, Newfoundland and Labrador Heritage Web Site Project