FINAL REPORT - International Joint Commission

Table C-1: Unit Costs for the Construction of New Shoreline Protection
ShoreUnit Shore Protection Cost ($/m) Shore Protection Cost ($ft)
ANNEX 2
CayugaCo 2,168 661
DurhamRM 2,012 613
Frontenac 2,432 741
HaltonRM 2,432 741
HamiltonRM 2,432 741
Hastings 2,012 613
JeffersonCo 2,488 759
Leeds 2,134 651
Lennox 2,432 741
MonroeCo 1,933 589
NiagaraCo 1,889 576
NiagaraRM 2,070 631
NorthumberlandRM 2,012 613
OrleansCo 1,889 576
OswegoCo 2,168 661
PeelRM 2,048 624
PrinceEdward 2,012 613
StLawrenceCo 2,134 651
Stormont 2,134 651
Toronto 2,048 624
WayneCo 1,933 589
Shoreline Protection Maintenance
Shoreline protection structures are already present for a large percentage of riparian properties exposed
to flooding and erosion hazards around the perimeter of Lake Ontario. Based on the parcel database,
approximately half of the shoreline length has been armoured with good quality seawalls and revetments.
For the evaluation of new regulation plans, it is assumed that these structures are stable, will be maintained,
and will continue to provide effective erosion protection. However, if a regulation plan results in more
extreme high water levels, there will be negative impacts on the existing structures that were designed for
the range of lake levels since 1960. The existing shoreline protection indicator quantifies the impacts of
the alternative regulation plans on the structures currently providing effective erosion control around the
perimeter of Lake Ontario and the St. Lawrence River.
The three principal modes of failure that require significant maintenance or complete replacement and that
are considered in the shoreline protection maintenance performance indicator are as follows:
• Age failures – degradation of materials, such as concrete or quarried stone;
• Overtopping failures – wave overtopping during storms (event driven);
• Downcutting failures – cumulative process at the toe of the structure.
Age failures are independent of lake levels. However, the volume of water overtopping a structure during
a storm is very sensitive to lake levels. In Figure C-2, the crest of the concrete wall is a product of the
design lake level and design wave height. If these levels are exceeded during a storm, the wall may fail or
require significant maintenance. The existing shore protection performance indicator evaluates a regulation
plan by cycling through the hydrograph and looking for storm events that would cause failure or require
maintenance of existing structures.
Options for Managing Lake Ontario and St. Lawrence River Water Levels and Flows
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