AVAILABLE OPTIONS FOR CONSIDERATION
There are three basic alternatives in response to an erosion problem: do nothing, relocate
endangered structures, or take positive action to halt it. The latter includes devices to armor the
shoreline, intercept or diminish wave energy before it reaches shore, or retain bluffs against sliding.
NO ACTION
The no action alternative is used by engineers to help evaluate different courses of action. When
confronted with an erosion problem, the first reaction is to take immediate action. What is not realized,
at first, is the expense of even low cost solutions. Therefore, it is advisable to estimate the losses
involved in doing nothing, particularly if only undeveloped land or relatively inexpensive structures are
threatened. Also, erosion may be caused by temporary factors (e.g., unusually high Great Lakes levels).
In such cases, it may be advisable to wait for the erosion rate to slow before taking any action.
RELOCATION
In most cases, however, some action is required. Before investing in shore protection, physical
relocation of your house or other structure should be considered. If this simply involves moving the
house back on the same property, an experienced professional engineer should be retained to evaluate the
required setback. Moving a house involves a considerable investment which could be lost if the house is
not moved back far enough.
If you have lived in one place for a long time (25 years or more) and have observed a steady
shoreline retreat over the period, you can compute an average annual erosion rate by dividing the total
retreat by the number of years observed. For instance, if the shoreline gradually receded 300 feet in 30
years, you can estimate the average erosion rate at about 10 feet/year. Therefore, if you moved your
house back 100 feet, you would add 10 years of life to the structure at the present erosion rate. If no
erosion occurred for years but then the shoreline suddenly retreated 300 feet in 5 years, however, a
setback would be both risky and inadvisable.
Even with gradual erosion, the rate could increase suddenly and eclipse a setback in a short period
of time. Therefore, an element of risk is involved in any setback. Relocation should be considered,
however, particularly if the house can be moved to a new site.
BULKHEADS AND SEAWALLS
"Bulkheads" and "seawalls" are terms often used interchangeably in referring to shore protection
structures. Bulkheads are retaining walls, however, whose primary purpose is to hold or prevent sliding
of the soil. While they also provide protection from wave action, severe wave action is usually beyond
their capacity. Seawalls, on the other hand, are massive structures used to protect backshore areas from
heavy wave action. Their size generally places them beyond the range of low cost shore protection.
They are also not generally needed in sheltered waters where large waves do not occur, except possibly
in the Great Lakes.
Bulkheads may be employed to protect eroding bluffs by retaining soil at the toe, thereby
increasing stability, or by protecting the toe from erosion and undercutting. Bulkheads are also used for
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