Digby Harbour Design

Condition and needs assessments led to a harbour upgrade design, and borehole results reshaped the breakwater into armour stone finished with a ballast-filled wooden crib.

Digby’s economy depends on its harbour, the link to the sea-based fishery and aquaculture. When the not-for-profit Digby Harbour Port Association took ownership in 2007, the harbour had fallen into disrepair.

Assess, then design

We undertook a comprehensive geotechnical investigation to document the condition of the wharf’s wooden and concrete structures, and interviewed stakeholders for a needs assessment. With Cormier Management Consulting, we provided design recommendations based on the needs of users and the community, with cost estimates: new floats, gangways and lighting, and, as the major component, a new 300 m breakwater.

When the ground changes the design

Boreholes revealed poor soil conditions, so the breakwater design had to change. A traditional armour stone breakwater was built to full height near shore. For the remainder, armour stone was built to a +1.5 m elevation and finished with a wooden crib filled with ballast rock to give maximum protection at low tide. We inspected the breakwater’s construction in 2013 to confirm conformance with the design.