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Myers Creek

Mitigation Site

Restoration Approach

In 2014, OHA installed several structures that mimic beaver dams, known as beaver dam analogues (BDAs). Adding these structures helps provide similar ecosystem services to those generated by beaver dams, and fosters conditions that may support the return of beaver in the future. OHA utilized natural wood materials to slow down and back up the water so that spring runoff will inundate more of the soil and create the conditions necessary for wetland plants and animals to flourish.

The beaver dam analogues have both widened the stream where it had been a narrow trench, and in some places have caused up to four feet of sediment to be deposited. This has raised the streambed in places so that it is no longer as far from the floodplain. OHA also placed large wood in the stream to help increase the structural complexity of the habitat. Some of these trees with rootwads are now completely buried in sediment, while others are still visible. OHA continues to monitor the site.

By implementing additional mitigation measures, OHA has aimed to:

  • Remediate some of the impacts created by loss of beaver, decades of overgrazing, and removal of woody debris
  • Raise the water table to support increased seasonal hydration of the floodplain soil and to support riparian vegetation
  • Increase the ability of the stream to capture sediment, and aggrade the streambed in closer proximity to the former floodplain
  • Increase the capacity of the stream and associated wetlands to store water for drought protection

View a panorama of the upstream-most BDAs on the site during spring 2016 high flows.

How was this Done: In-stream Construction

Pilings were driven into the streambed using a pneumatic hammer, powered by a large air compressor. The pilings were placed across the stream to form the structure into which red osier dogwood cuttings were woven. OHA also installed large woody debris in the stream for habitat enhancement. Watch the process in the slideshow on the right.

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