Salmon Spawning Habitat Enhancement – Southwest Brook

Description: The Bedeque Bay Environmental Management Association (BBEMA) intends to improve access to Atlantic salmon spawning and rearing areas on the Southwest Brook, a tributary of the  Dunk River.

The Dunk River is one of the oldest historical Atlantic Salmon rivers on PEI. In 1874, construction of PEI’s first Atlantic Salmon fish hatchery was proposed, with the Dunk River selected as the hatchery site. The hatchery began operations there in the fall 1879.

Redd surveys and research conducted by BBEMA have shown that the higher value spawning and rearing habitats within the Dunk are found within the headlands and the primary tributaries of the system. Historical data, in combination with yearly redd surveys, has proven that the Southwest Brook (branch), which flows down through the Shamrock/Kinkora region, has significance as a primary stream offering both viable spawning/rearing habitats. Currently the tributary’s road crossing on Newton Road 225 is a hung culvert that is a barrier to juveniles and is potentially preventing juvenile salmon from reaching rearing areas and adult salmon from reaching their spawning sites. As a result of this culvert obstruction 86% of the Southwest Branch tributary is barred to Atlantic Salmon juveniles. By restoring safe fish passage for all life stages of fish present in the stream, access will be opened to approximately 6 km of important upstream spawning and habitat.

After onsite consultations with ASF staff in PEI, it was decided that the most feasible method is to install a rock Newbury weir downstream from the culvert. The goal is to raise stream water levels upstream of the weir crest by approximately 6 inches above pre-construction conditions. Backwatering the culvert outlet will reduce water velocities in the culvert, resulting in conditions more favourable to juvenile fish passage. This would result in:

• Elimination of a culvert outlet drop.
• Providing a resting pool for migrating fish;
• Allowing for adequate water depths in the culvert though backwatering;
• Reducing the velocity at the culvert outlet;
• Reducing downstream erosion and headcutting; and
• Providing a transition zone between the culvert and the natural stream channel downstream.

To optimize further the potential spawning/rearing habitat within this tributary, BBEMA will undertake stream enhancement work above and below this crossing. The installation of brush matting will mitigate bank erosion and help maintain a natural and more complex channel. Riparian tree planting (350 trees) will create riparian shading and help restore the healthy forest cover that was lost as a result of extensive tree loss/damage from Hurricane Fiona. Spawning habitat enhancement will include raking of beds and the installation of man-made reds below the culvert.