Stream Restoration
Habitat Enhancement
Deflectors, like this one under construction in Irish Cove Brook, help to narrow a stream that has become over-widened. Many streams are over widened nowadays due to human activity such as improperly designed culverts, removal of riparian vegetation or intense deforesting activity in the watershed, extreme weather, etc. Erosion of the riverbanks creates a wider stream which usually correlates to a shallower stream. Shallow streams warm up easily in the sunshine which is bad news for fish like brook trout (atoqa’sue’katik) and salmon (plamu) who require cold temperatures.
By installing deflectors we are pulling the riverbank into the water at calculated meander distances and encouraging revegetation. The deflectors also direct water in a more concentrated way which allows it to naturally cut into the streambed, restoring deeper topography.
Digger logs like this one in Trout Brook, Mira Watershed, are set into the streambed at a 30 degree angle to the bank. As the water runs over them it cuts into the streambed below, carving a pool into the bottom. Pools are important in stream ecosystems because they provide a safe deep place for fish to find refuge from predators and from extreme temperatures.
When water flows over the logs it creates bubbles, like a wave crashing into the stream, adding oxygen to the water which improves water quality for freshwater organisms. Installing digger logs at a 30 degree angle at calculated distances along the stream helps the water move in a back and forth pattern and can restore the natural meander of the stream.
Covered banks are installed in long straight runs of stream with no cover for fish to hide from predators, and/or when water flow is causing erosion. They are meant to protect the stream bank and must be built to withstand harsh conditions.
These structures provide a safe place for stream organisms in areas where a riffle-run-pool pattern has been lost, or the riparian zone has been damaged. This covered bank in McNabs brook, Bras d’Or Watershed, is 4m long.