Review of Dynamic Beach
Shorelines in Tiny Township

Most of Tiny Township’s 72 km shoreline has been identified by the Ministry of Natural Resources (MNR) as dynamic beach, one of three natural hazards recognized in the Provincial Policy that result in mandatory setbacks for development. The minimum setback for a dynamic beach is 45 m inshore of the 100 year flood level or as determined by a site-specific engineering study.
W.F. Baird & Associates, marine engineers, were retained by Tiny Township to undertake a screening study to identify reaches of Tiny’s shore which may not be dynamic beaches. On September 12, a representative from Baird, Fiona Duckett, presented the essence of their findings to Council. This account draws on that presentation and uses illustrative pictures and maps from it.

What is a dynamic beach?: Beaches that undergo continuous or change due to natural erosion and accretion are dynamic. (Ms. Duckett noted that development that encroaches into the dynamic beach zone is at risk. More, the Provincial Policy recognizes the protective benefits realized by maintaining the integrity of the dynamic beach.)

Dynamic Beach Definition (Technical Guide, 1996):
For a beach to be considered dynamic, it must satisfy three criteria:
• Beach or dune deposits exist landward of the water; AND
• Beach or dune deposits are equal to or greater than 0.3 m thick, 10 m wide and 100 m in length; AND
• The minimum fetch measured over an arc extending 60 degrees either side of shore perpendicular is greater than 5 km. [The fetch is the distance that wind may blow unimpeded over water toward shore.]

Dynamic Beach Hazard Limit
The Limit is calculated as follows:
100 year flood level (178.0 m level)
+ flood allowance (15 m)
+ dynamic beach allowance (30 m)
100 year flood level + flood and dynamic beach allowance from an engineering study

Site Visits and Classification: On July 14 and 15, 2005, Baird visited 51 sites along Tiny’s 72 km shoreline. At each point, they made an assessment for roughly 100 m in each direction and took pictures. At each point they classified the shore as Dynamic Beach, Possible Dynamic Beach or Non-dynamic Beach.

Dynamic Beach Shorelines: Baird classified 45% of Tiny’s shoreline as dynamic beach. This includes the western shore from Woodland Beach to Gidley Point (just south of the 18th Concession Road West) and also the centre of Thunder Bay Beach. In their view, the dynamic beach hazard applies for these shorelines. While site specific studies could be undertaken in the hope of reducing the 45 m dynamic beach hazard setback, they would not expect significant reduction along most of this shoreline, though there might be some reduction where a property is protected by a point or a hook of land.

Possible Dynamic Beaches: Baird estimated that 45% of Tiny’s shore is possible dynamic beach. This includes most of shoreline from Gidley Point (near the 18th Concession Road West) to east of Sawlog Point. These areas meet some of the criteria for a dynamic beach; however there is some level of uncertainty for some of the criteria. Site specific studies would be required to determine if they meet the full dynamic beach criteria. For those that are dynamic
beaches, Baird would anticipate that the 45 m setback would be reduced. And, of course, for those that are not dynamic, the setback from the 100 year flood level would be 15 rather than 45 m.

Non-dynamic Beach Shorelines: Baird estimated 10% of Tiny’s shoreline as being non-dynamic beach. Such shorelines include protected areas (for example those in the lee of Beausoleil Island). Nonetheless, site specific studies would be required to define boundaries of non-dynamic beach shorelines. The dynamic beach hazard does not apply, so the setback would be 15 m from the 100 year flood level.

Map Showing the Classification of All 51 Points: This is of considerable interest, but it did not reproduce well. Once Baird’s detailed report has been submitted, those needing a reduction in setback should consult it at the Township Offices. If you happen to live within 100 m of one of the 51 points, then at least part of your engineering study has been done. There are some surprises: the west side of Thunder Bay, for example, has instances of all three kinds of shore.
Conclusion: Ms. Duckett noted that the classifications apply only to sites visited. However, it was clear from the discussion that the report will be of great assistance to owners needing a reduction in mandatory setbacks, especially where the shore is likely to be either possible dynamic or non-dynamic. This is good news for owners who want to build or expand current dwellings on 55% of Tiny’s shoreline.