11/28/2011

High Tides And River Levels Moving Drift Logs

This large drift log was flushed out of the Sooke River two years ago

Fall and winter are the seasons that put the rain in coastal rainforest. The calm summer is a distant memory that dropped with the leaves of the maples and oaks. Now is the time for gales, tropical punch drenching rains, and the highest tides of the year.

The drift log was lifted by recent high tides and swept away like a big canoe
With the summer drought over, the life-giving rains that define the forest begin to fall. Conifers that have been growing so slow that they are near dormant now have the rainfall that they have been missing for the past several months.

Rain-swollen rivers rise to heights that enable thousands of pacific salmon to return to their birthplace and continue a cycle that has been taking place for millions of years. The forest, and almost 200 species of animals, will benefit from the salmon's nutrient bounty. This includes Bald eagles which gather in large numbers to feast on the dead salmon which dot the low tide sand bars.

This huge stump has been on Billings Spit beach for many years -
it is unmoved by even the highest of tides.

After several big storms the ground nears saturation, and water begins to flow in low lying areas. Previously dry rock faces now sport gushing waterfalls, and the moss is puffed with moisture and at its brightest green.

The water rushes over the land and down to the ocean. River water levels reach several times the meager summer flow, washing accumulated woody debris, including whole, large trees, into the estuary in the harbour.

This cedar drift log lasted a few weeks on the beach before
being cut, floated, and hauled away

When high river flows combine with perigean spring tides (20% higher than normal), flooding is possible in coastal regions, especially if there are strong winds. On south Vancouver Island the highest tides of the year take place right now, then the end of December 2011, and mid-January 2012.

Another large cedar stump washed out of the Sooke River into the estuary.
It was only a few days before a boat tied up, cut the roots off, and hauled the log away.
The highest water levels of the year flush drift wood from beaches to float on the currents until they find a new resting place. The tide flats of the Sooke River estuary are often cleaned of old drift wood, before new trees and wood are washed out of the hills and end up taking their place.

Some drift logs stay for years, others will be gone by spring. Valuable large drift logs are hauled away by enterprising coastal residents to become shingles and shakes, posts, beams, and firewood. Their winter work is rarely witnessed by fair weather visitors.

Although not traditionally a part of the tourism season, late fall and winter offer exciting opportunities to see the coastal forest during its most tumultuous, powerful, and ever-changing moments as it interacts with the wind, water, and waves.  

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