Stream Restoration
Extensive logging removed riparian trees throughout many watersheds, which has led to deteriorating streambanks, a discharge of sediment and impacts to the stream channel. This continuous watershed instability negatively effects water temperature, sediment load and fish habitat. ET utilizes a restoration approach called Natural Channel Design to restore critical stream parameters. ET’s Natural Channel Design approach includes:
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Assessment and surveying of the stream using Natural Channel Design methodology.
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Collection survey data and biological data necessary to complete project permit applications and design a rehabilitation project.
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Monitoring the water temperature to select project site(s).
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Designing a stream restoration project to restore watershed function and stability.
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Restore the stream channel’s shape, dimension and profile.
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Enhance instream trout habitat by strategically positioning large woody debris, rock vanes and “J” hooks into the channel.
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Reconnect the channel to the floodplain.
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Create new floodplain benches and wetlands to retain water on the landscape.
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Raise the groundwater table.
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Stabilize streambanks with use of Toe Wood/Root Wads.
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Rehabilitate the riparian overhead tree canopy with native vegetative species.
Stream Surveying and Restoration Design
ET uses the science-based Natural Channel Design methodology to assess and survey impacted stream reaches. This assessment/surveys method collects data from the impacted stream reach and compares it to several stable stream sections. All survey work is performed using a geomorphic trained Stream Specialist. Our assessment data collects stream width to depth ratios, floodplain elevation, erosion calculations, longitudinal profile, cross-section elevation and vegetation cover.
The survey data is entered into a specialized stream restoration computer-based program to create plans and specifications that will restore impacted stream features. These restoration plans create the basis for the construction project by depicting channel shape, size and dimension reconfiguration, placement of structures, streambed depth, streambank elevation and any stream channel realignment.
Another advantage of using ET for stream project designs is our projects are created to be self-maintaining due to our understanding of precise streambank elevations, channel shape and sediment transport. When the Natural Channel Design projects are properly designed, it results in a stable channel, that transports sediment, with an abundance of instream woody debris that creates scour pools and retained spawning gravels.
Identified an Eroding Streambank during the Rapid Stream Assessment
Restoration Construction
Restoration Construction
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Historically large instream woody debris was prevalent in watersheds. This large wood created structure to the stream and created side channels, stabilize of banks, connected floodplains, retained spawning substrate and scoured sediment deposits. Today, much of this wood has been lost due to channelization and flooding, which has led to an increase in channel instability, bank erosion, and sediment discharge.
To restore these stream impacts, ET imports large wood to rehabilitate the shape and pattern of the stream channel. Besides creating a stabilize and functioning channel, this substrate redirects current flow, creates deep scour pools, retains spawning gravels and stabilizes streambanks.
This construction method that utilizes only natural materials, differs from traditional restoration methods that armor streambanks with riprap. The benefits of natural materials are the enhancement of instream habitat that support fish and a more aesthetic appeal.
