Introduction
Problem:
Damage
to
miscellaneous
facilities,
such as
fences and
boat
ramps, can
be due to
high
velocity
flows that
erode
supporting
materials,
or carry
debris
that
impacts
and then
damages
the
facility.
Mitigation
Objective:
To
protect
miscellaneous
facilities
from
future
damage due
to high
velocity
flows.
B.1
Install
Sacrificial
Fence
Sections
Install
sacrificial
(break-away)
fence
sections
in
boundary
or other
fences
(i.e.
fence
sections
designed
to fail at
strategic
locations)
to allow
floodwaters
to pass,
relieving
pressure
on
adjacent
fence
sections,
preventing
major
damage to
the fence.
Sacrificial
sections
should be
designed
so that
the failed
sections
do not
become
loose in
the
floodwaters
and create
additional
debris or
cause
collateral
damage.
Effectiveness:
- Allows
the
passage
of
high
velocity
flows
as
well
as
debris
in
restricted
drainages.
Limitations:
- Sacrificial
fence
sections
may
require
repairs
after
flood
events.
- May
not
be
effective
in
preventing
damage
in
situations
where
floodwater
velocities
cover
a
larger
area
than
within
the
traditional
flood
channel.
Considerations:
B.2
Replace
Boat Ramp
Material
With
Concrete
When
boat ramps
are
damaged by
erosion,
replace
the eroded
gravel
boat ramp
or the
foundation
material
eroded
from under
a concrete
boat ramp
with
concrete
Effectiveness:
- Replacement
of
eroded
material
with
concrete
may
be
very
effective
in
areas
of
infrequent,
minor
erosion
damage
- Other
measures,
such
as
riprap
or
other
slope
protection
techniques
applied
to
the
downstream
side
of
the
ramp,
may
increase
the
effectiveness
of
this
mitigation
alternative
Limitations:
- May
not
be
effective
in
situations
where
the
boat
ramp
is
frequently
inundated
and
damaged
by
high
velocity
flows.
- Relocation
of
the
ramp,
if
possible,
or
other
alternatives
such
as
construction
of
a
jetty
to
protect
the
ramp
should
be
considered
in
these
instances.
Considerations:
B.3
Construct
a Jetty to
Protect
Boat Ramp
Construct
a jetty
upstream
from the
boat ramp
to protect
it from
high
velocity
flows.
Effectiveness:
- Construction
of
a
jetty
upstream
from
the
boat
ramp
may
be
very
effective
in
areas
of
moderate
to
high
velocity
flows.
- Other
measures,
such
as
riprap
or
other
slope
protection
techniques,
applied
to
the
downstream
side
of
the
ramp
may
increase
the
effectiveness
of
this
mitigation
alternative
Limitations:
- Consider
relocating
the
ramp
to
the
slackwater
bay.
Considerations:
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