|
|
||
 Selection of Site-specific Stabilization Techniques
dike design should take into account the safety aspects. A gently sloping dike profile will be
required, which may result in the structure protruding further into the channel than is
acceptable from the standpoint of channel alignment and cost. Dikes which are built in
shallower water and areas of slower currents may be acceptable from the standpoint of
channel alignment, cost, and safety, but since deposition often occurs within the dike field,
these dikes may become unusable as launching points.
Dikes are convenient for pedestrian access for fishing, but safety aspects should be
considered in design as appropriate for the site conditions.
Other examples of safety considerations are:
An easily traversed armor material will be safer than one which is slippery or
jagged. Vertical walls or steep slopes may need guardrails, limited access, or
other measures.
If the area is likely to be used by boaters or swimmers, some types of
stabilization work, such as "jacks" could be detrimental to safety.
"Drop-offs" (areas where the depth changes suddenly from shallow to deep)
may be hazardous.
Consultation with the project sponsor and safety specialists may reveal other advisable
precautionary measures.
5.2.2.4 Preserve Natural Aesthetics
The simplest and least subjective approach to comparing aesthetic merits or
weaknesses of various methods is to assume that minimizing the visual impact of bank
protection work is desirable. Therefore, disturbing the site as little as possible and using
natural materials are desirable features for a stabilization method.
Site characteristics obviously vary, and a material such as stone may be aesthetically
suitable for most applications, but unsuitable for some. Some armor materials, such as
concrete products, are not natural materials, but may be used in a form which gives a
somewhat natural visual impression. Other materials, such as rubble or used tires, have little
to recommend them aesthetically, although with time, vegetation may reduce the impact.
The aesthetic impact of indirect protection methods is somewhat mitigated by
minimizing disturbance to the existing streambank. Still, retards will have a significant impact
on site aesthetics, although the degree of impact depends upon the materials chosen, and the
impact often decreases with time, as deposition occurs and vegetation is established. Dikes
also have a visual impact, but being intermittent, preserve more natural-appearing bank than
107
1 7
|
||
|
||
