2015 Watershed Restoration Season in Review Restoration

Many of the streams in the Dartmouth area have been degraded in some way either through historical land use or more recent commercial and residential development. This degradation can leave streams straightened, widened and shallow with fragmented riparian vegetation. Poorly installed or damaged culvert can block fish passage and create habitat fragmentation. This leads to streams that lack their historic natural features and functions. It can also lead to increased water temperature, bank erosion, sedimentation, pollution, and flow velocity leading to decreased biodiversity and limiting fish population potential. Invasive species like smallmouth bass and chain pickerel can add to these negative impacts.

Clean’s Watershed Restoration Team, with the mentorship and support of the NSLC’s Adopt-a-Stream program, spent 2015 working on projects throughout Dartmouth’s urban watersheds to mitigate these issues. To this end, the team planted trees, created in-stream structures, removed debris and performed maintenance on previously installed structures throughout the Cow Bay and Shubenacadie River watersheds.

Step-pools were created in steeper sections of Russell Lake Brook (29 m) and Bell Brook (130 m) to create better fish passage and habitat and provide resting pools for fish moving upstream. 508 trees of a variety of species native to Nova Scotia were planted within the riparian zones of Settle Run (278), Forest Hills Run (151), Bell Brook (48), and Frenchman Brooks (31). These trees will provide bank stabilization, limit stormwater flow that reaches the streams, and eventually provide shade helping to keep stream temperatures low for better fish habitat. Debris was removed from over 3.2 km of stream length in Bell Brook (394 m), Smelt Run (1160 m), Frenchman Brook (306 m), Grassy Brook (456 m), and Broom Brook (920 m) to help consolidate flow, remove blockages and improve fish passability. Cattails were removed from an 80 m length of Frenchman Brook. Gravel spawning beds in both Frenchman Brook and Grassy Brook were cleaned of sedimentation and algae. A bank stabilization structure was also installed in Ellenvale Run reversing bank erosion and maintaining support for the walking bridge just upstream.

Monitoring and assessment is an essential part of quality watershed restoration work. In 2015, water quality data was collected monthly from 20 locations, upstream and downstream of restoration work in every stream we work in. Electrofishing species presence/absence surveys were conducted in ten separate streams within the Cow Bay and Shubenacadie River watersheds. Fish habitat assessments of eight different streams were also conducted within this region. 15 culverts were assessed for fish passability between the Cow Bay River watershed and the Horne’s Brook watershed.

Baseline monitoring and assessments allow Clean to measure the impacts of our restoration work over time and gauge the success of our work. It also allows us to identify large changes or trends over time in water quality and helps determine locations in need of additional restoration work.

Outreach

In 2015, Clean sought to engage and educate the public about the importance of urban stream restoration and overall watershed health. Clean hosted four tree planting events this year focusing on riparian planting to highlight the important role trees play in stream and watershed health. 900 trees were planted within Dartmouth and Halifax riparian zones and over 1350 m² of habitat was restored with the help of 135 participants.