Beneath the Surface: More to spring runoff than meets the eye

spring runoff is a very important event in the natural world.

Article adapted and reproduced with permission from the original author, Kalista Pruden.

 

Many people think of spring runoff as a nuisance because of the resulting high water events or localized flooding. During the spring runoff period, there is more water in rivers, lakes and streams, creating momentum to stir and move things. When runoff slows to an end, the objects (or sediment) moved by high water are deposited or “dropped-off” in a new place.

This process can greatly change the characteristics of a water body and its surrounding area. Nevertheless, spring runoff is a very important event in the natural world.

As spring snow melt and rain rushes into rivers, lakes and streams, tiny sediment particles are picked up and carried within the water, making it turbid (murky or dirty). As more water pours in, larger particles like pebbles, sticks, cobbles and logs get pushed along. Sometimes insects and small animals get carried downstream in the flows, too.

During normal or low water levels, sediments do not move as easily and build up as deposits on the lake or river bottom. When runoff arrives, these deposits are distributed to new locations, benefiting plants, animals and insects in the ecosystem. Consistent low or average flows can cause too many nutrients to build up in some places and not enough accumulation in other places.

Repositioning of sediments on the bottom during runoff also creates a greater variety of aquatic habitat, attracting more critters to the ecosystem. Sometimes pools are filled in and new ones are formed, or the shape or path of the water body changes. New gravel beds for fish spawning and aquatic insects appear. Mud flats develop, providing a smorgasbord for birds and bugs and fertile soil for plants. Woody debris gets lodged into banks or sinks to the bottom, producing homes for all kinds of creatures.

Like many ecosystems, the Columbia River and Wetlands depend on regular runoff and flooding to stay healthy and diverse. Even though the Columbia River Basin is the most hydroelectrically developed river system in the world, Lake Windermere is part of the only free-flowing section beginning at the headwaters in Canal Flats. Natural, healthy amounts of runoff and flooding enter the portion of the Columbia River from Columbia Lake to the river’s first dam at the Kinbasket Reservoir north of Golden.

The Ministry of Forests, Lands and Natural Resource Operations reported that “given the snow conditions this year for most of the province, extreme weather, such as extreme precipitation or combined hot and wet weather, would be required to produce flooding or higher than expected flows” (Snow Survey and Water Supply Bulletin, April 2015). Nonetheless, even in years with normal or lower than normal snow packs, flooding is always possible during the snow melt freshet season. Be prepared for variable water levels, and remember how important runoff is to nature.

For more information, please contact the Lake Windermere Ambassadors at 250-341-6898 or info@lakeambassadors.ca, or visit the project office located at 625 4th Street, South Annex.

The Lake Windermere Ambassadors are a charitable organization representing a cross-section of community stakeholders committed to directing water quality monitoring and stewardship.  Their work is made possible by the generous support of Columbia Basin Trust, Columbia Valley Local Conservation Fund, Columbia Valley Community Foundation, the Real Estate Foundation of BC, the District of Invermere, the Regional District of East Kootenay, and member donations!

Beneath The Surface is based on the principle that there is often more to know than what is visible from the “surface” of an issue. If there is something that concerns you about the lake and you want to get to the “bottom of it,” call Lake Windermere Ambassadors program co-ordinator Megan Peloso at 250-341-6898 or email info@lakeambassadors.ca and inspire the next column!

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