The River That Meets Ocean But Do Not Mixes

The Fraser River in British Columbia winds for almost 1,400 kms and thus makes it the longest river in this Canadian province. The river is fed by snowmelt. The melt flows alongside the Rocky Mountains to a comparatively flat plateau. The Fraser River continues to travel down through the Coast Mountains and the Fraser Canyon till the time it reaches a 130 – kilometer – wide (81-mile-wide) floodplain. The floodplain empties into the Strait of Georgia.
During the journey of the river, it picks up and carries a lot of silt which is approximately 20 million tons each year. Most of the silt flows into the Strait of Georgia while around 3.5 million tons are left behind and collected in the lower of the river valley. The presence of silt gives the river a milky white color. This effect is noticeable at the river’s mouth where the freshwater plume is clearly seen even from the space.
The special feature about the river is that it does not only carry silt sediments with it but also nutrients that support the growth of phytoplankton into the strait and the ocean. The water reflects blue, green, or milky color due to the blooms of phytoplankton. Grazers like sockeye salmon hatch in the Fraser and the blooms become the center of a food web for these grazers. When the salmon return to Fraser four years later to spawn then those nutrients are also recycled back into the Fraser.
The Fraser River reaches an ocean near Vancouver. The freshwater carried by it mixes with the ocean water to form a thin plume. The thin plume of buoyant brackish water is a ‘showpiece of the Strait of Georgia’ according to one of the oceanographers.

By: Kiara Sharma

Mahaveer Public School