Nova Scotia offshore wind risk readiness
Introduction
The Government of Canada and the Province of Nova Scotia have established a framework to support large-scale offshore wind energy development, with a target of licensing up to 5 GW of offshore wind capacity by 2030. Following a regional assessment process initiated in 2023, four Wind Energy Areas (WEAs), namely French Bank, Middle Bank, Sable Island Bank, and Sydney Bight (Figure 1), were officially designated in July 2025 as the first offshore areas available for future wind energy development.
This desktop study, produced by GDG, a Venterra Group company, focuses on two of these designated WEAs – Middle Bank and Sydney Bight, and compiles publicly available geological, geophysical, geotechnical and environmental information to characterise regional geological conditions, seabed morphology, subsurface stratigraphy, and potential geohazards. The assessment provides an initial understanding of ground conditions within the two WEAs and identifies key considerations for future site investigation, engineering design, and offshore wind development planning.
Figure 1 – Designated Wind Energy Areas (WEAs) on Scotian Shelf
Project at a glance
The study provides a clear technical baseline for site screening, survey strategy, geohazard awareness, foundation suitability, and future development of the ground model. It identifies where confidence is relatively high, where uncertainty remains, and which investigations are most valuable before concept design, consenting, and procurement decisions progress.
Why this matters
Offshore wind development depends on an early understanding of seabed and subsurface risk. In Nova Scotia, the designated areas combine strong wind potential with complex glacial geology, variable shallow-data coverage, potential geohazards, and marine constraints.
By converting dispersed public datasets into an integrated technical narrative, the desktop study provides an overview of how public information can be used to help developers prioritise survey investment and make better-informed decisions at an early stage in the project lifecycle. The study also serves as a regional base to which results from the more recent marine data collection campaigns led by the Geological Survey of Canada (GSC) across the four WEAs can be added, and to further discuss their impact on offshore wind farm development.
Geological background summary
The geological background for the Nova Scotia WEAs reflects a complex bedrock framework overlain by glacial and post-glacial deposits. Onshore Nova Scotia is formed by the Avalon and Meguma terranes, which were accreted during the Acadian and Neoacadian orogenies and are separated by the Cobequid-Chedabucto Fault Zone / Glooscap Fault / Minas Fault Zone.
Offshore, the geological succession records rifting and passive-margin development from the Late Triassic onwards, with red beds, dolomite, and evaporites, followed by marine sands, limestones, shales, and, later, deep-water sediments. The pre-Quaternary geology map in Figure 2 indicates that Middle Bank is underlain by Cretaceous to Cenozoic sedimentary rocks, while Sydney Bight lies over non-marine Palaeozoic, mainly Carboniferous, sedimentary rocks.
Figure 2 – Pre-Quaternary geology
The Quaternary history is dominated by repeated glaciations, with the last major ice advance during the Late Pleistocene Wisconsinan stage reaching the Scotian Shelf close to the shelf break at approximately 21 ka. These glaciations produced till, morainic and fluvio-glacial deposits onshore and offshore, including end-moraine complexes, till tongues, incised channels, flow-parallel landforms and glacio-marine basin infills.
The expected Quaternary stratigraphy comprises multiple generations of basal tills directly overlying bedrock, overlain by ice-proximal-to-distal glacio-marine deposits and younger post-glacial lacustrine, estuarine and marine sediments.
In summary, Middle Bank is expected to be characterised by Cretaceous to Cenozoic bedrock overlain by a potentially thick Quaternary sequence that may include tills, tunnel-valley fills, glacio-marine deposits, and a post-glacial sand-and-gravel veneer. Sydney Bight is expected to comprise Permo-Carboniferous bedrock overlain by Quaternary glacial to post-glacial deposits (Figure 3).
Figure 3 – Seabed sediments along the Scotian Shelf and an example of the expected subsurface stratigraphy in the Middle Bank
Figure 4 shows substantial variation in water depth across the Nova Scotia offshore region, from shallow bank areas of approximately 20–60 m to deeper channels and slope areas exceeding 200 m.
The two designated Wind Energy Areas lie mainly on or near the continental shelf, where water depths are generally moderate relative to the surrounding deeper basins; however, local channels and slope settings may introduce greater depth and gradient variability.
Figure 4 – Bathymetry for Scotian Shelf region
Technical findings for site characterisation
Against this regional geological framework, the following findings identify the conditions most relevant to site characterisation, survey design and foundation screening in Middle Bank and Sydney Bight.
01
Strong offshore wind context
Middle Bank and Sydney Bight are in areas with favourable wind-resource potential, positioned within Nova Scotia's designated offshore wind planning framework.
02
Generally low-gradient seabed
Both WEAs are characterised by relatively flat seabed conditions overall, although steeper channel heads and flanks near site boundaries require closer investigation.
03
Coarse seabed sediments are expected
Post-glacial sand and gravel dominate across both WEAs, with local occurrences of glacial sand, mud, diamict, and coarse material that may affect cable burial, foundation installation, and intrusive investigation planning.
04
Glacial geology is a key design consideration
The study highlights glacial deposits, tunnel valley fills, and variable Quaternary successions, all of which may influence ground model uncertainty and foundation feasibility.
05
Data limitations are material
Public bathymetry, seismic, and geotechnical datasets provide a useful baseline but are not sufficient for detailed design. Higher-resolution seabed and shallow subsurface data are required. Upon release, the datasets acquired by GSC and the interpretations carried out should be integrated into the current assessment in order to better understand ground conditions, geohazard distribution, and any outstanding data gaps.
06
Hazards and constraints are manageable if addressed early
Hazards and constraints, such as channels, shallow gas, sediment mobility, slope instability, sea ice, hurricanes, fishing, marine traffic, submarine cables, designated areas, shipwrecks, and UXO, should be incorporated into future survey design and risk-management strategies.
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Figure 5 – Seabed overview of the Scotian Shelf and the two WEAs: Middle Bank and Sydney Bight
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Figure 6 – Example of constraints on the Scotian Shelf
How GDG adds value
At GDG, we convert complex offshore datasets into clear, decision-ready insight. For developers, investors, and project teams, this means early understanding of technical risk, better prioritisation of survey expenditure, and a stronger basis for consenting, design, procurement, and stakeholder engagement. We provide this through:
Integrated geoscience interpretation
Combining geology, geomorphology, geophysics, geotechnics, and marine constraints into one coherent baseline.
Early risk visibility
Identifying the conditions most likely to influence survey design, foundation selection, cable routing, installation methods, and project schedule.
Survey strategy support
Translating data gaps into targeted, practical recommendations for geophysical, geotechnical, metocean, UXO, archaeological, shallow gas hazard assessment, and sediment mobility studies.
Ground model readiness
Establishing a foundation for progressive ground model development as new project-specific datasets become available.
Risk maps for early decision making
The workflow (Figure 7) adopted for the foundation suitability assessment follows a risk-based, integrated site characterisation approach. Geological, geophysical and geotechnical datasets are first collated as key inputs, including water depth, seabed slope, seabed substrate, stratigraphy, bedrock level, soil and rock strength parameters, consolidated soil conditions and organic matter content. These datasets are supplemented by information on external constraints such as wrecks, offshore infrastructure, designated areas, UXO and military exercise areas, fishing activity and marine traffic.
The compiled information is then integrated to assess site conditions and to identify relevant hazards and associated risks. Each hazard is graded in terms of likelihood and severity using predefined criteria, and the resulting risk scores are combined through spatial analysis to generate a risk map. This map provides a transparent basis for interpreting the distribution of ground-condition and constraint-related risks across the assessment area and is subsequently used to inform the foundation suitability map.
Figure 7 – In-house workflow
Risk maps translate risk-register information into a spatial format that clearly communicates the distribution, relative intensity and overlap of geohazards across the assessment area. They provide a practical link between qualitative hazard screening and more detailed assessment, helping identify zones where ground conditions, seabed constraints or environmental factors may elevate development risk and require further investigation, design optimisation or mitigation.
The workflow is structured into two stages. First, individual hazard-risk layers are developed by assigning likelihood and severity ratings to selected hazards using the available geological, geophysical, geotechnical and constraints data. Second, these layers are combined to produce summary risk maps that show the spatial interaction of multiple hazards. The outputs provide a consistent basis for comparing relative risk between zones and can inform early screening, survey prioritisation, foundation-suitability assessment and progressive ground model refinement as new data become available.
Figure 8 – Likelihood & severity map combined to produce risk map.
Foundation suitability assessment
A preliminary foundation suitability assessment was undertaken using water depth, seabed substrate and interpreted bedrock depth as the primary screening parameters. Across the assessment area, water depths typically range from approximately 50 m to 200 m, while bedrock is generally interpreted to occur between 0 m and 70 m below seabed, locally increasing to around 200 m below seabed within buried channel features.
These conditions indicate that floating foundation concepts are likely to represent the most feasible development option across much of the area, particularly where water depths exceed the practical limits for conventional fixed-bottom solutions. Potential floating foundation systems may require catenary, taut, semi-taut or tension-leg mooring arrangements, supported by anchor solutions such as drag-embedment anchors, suction buckets, driven piles or drilled-and-grouted piles, depending on the local seabed and ground conditions.
50–200 m
Typical water depths across the assessment area
0–70 m
Interpreted depth to bedrock below seabed, locally around 200 m within buried channels
≤50 m
Water depths in which fixed foundation options are expected to be suitable
Figure 9 – Water depths greater or less than 50 m on Scotian Shelf
By contrast, fixed foundation options such as monopiles, gravity-based structures and piled jackets are expected to be suitable in water depths not exceeding 50 m (Figure 9).
In areas where the bedrock is shallow (<20 m BSB), suction buckets, DEAs, and driven piles (A) may be unsuitable, leaving drilled-and-grouted anchor piles (B) potentially most suitable, subject to rock conditions, as seen on Figure 10.
line drawing of part of seismic profile 94032_SG_NSRF_323_0040 (GSC)
line drawing of part of seismic profile 73006_AG_181_0217 (GSC)
Figure 10 – Schematic seismic profiles with the foundation options based on the bedrock depth
Recommended next steps
The desktop study confirms that additional data acquisition is essential before detailed OWF design. Recommended next steps include:
- High-resolution multibeam echosounder bathymetry and backscatter
- Full-coverage side-scan sonar
- Magnetometer data
- Sub-bottom profiler and multi-channel seismic acquisition
- Geotechnical sampling and testing
- Metocean data collection
- Targeted assessments of UXO, shallow gas hazards, sediment mobility, slope stability and archaeological potential
There is an ongoing effort from the Government of Canada to acquire high-resolution geophysical data and seabed samples to de-risk the WEAs and assess their suitability for development. However, a detailed assessment of these datasets is required to determine whether they need to be supplemented by other investigations in later development phases.
By sequencing future investigations around the principal uncertainties identified in the desktop study and by developing integrated ground models incorporating the new data, project teams can move from regional screening to a robust, evidence-based site characterisation strategy.
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