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 Appendix B: Bioengineering for Streambank Erosion Control -- Guidelines
must be careful to use low-lying and flexible vegetation that lays down with water
flows if hydraulic conveyance must be maximized. In such cases, use flood-tolerant
grasses or grass-like plants and shrubby woody species.
d.
Select species that will not be dug out or severely grazed by animals, especially
muskrat (Ondatia zibethieus), nutria (Myocastor coypes), beaver, Canada geese,
and carp (Cyprinus carpio). Other animals may influence plant growth and survival.
If plants chosen are unavoidably vulnerable to animal damage, then plant protection
measures must be used, such as fencing, wire or nylon cages around them, or use
of repellents.
e.
Determine additional special requirements and constraints of the site. For instance,
some sites may be prone to sediment deposition or have a bank geometry that is
almost vertical. In such cases, it may be difficult to obtain success with emergent
aquatic plants that may become covered with sediment and suffocate or which have
too deep of water in which to grow unless the bank is reshaped. The former
situation may necessitate the use of willow that can be planted as cuttings or posts
and be less susceptible to complete coverage by sediment.
f.
Prepare a suite of species that would be suitable. This may be limited to those
currently available from commercial sources if there is no possibility to collect in the
wild or have plants contract grown.
Pierce (1994) also gives a number of steps and advantages and disadvantages of the three
methods of acquiring plants and these have been adapted with some modifications below.
Each project will have unique situations, but the following will serve as a guide.
Purchasing Plants
a.
Acquire a list of wetland plant suppliers, such as "Directory of Plant Vendors,"
(USDA Soil Conservation Service, 1992). Request vendors' catalogs and plant
availability lists.
b.
Determine in what condition the plants from each supplier are delivered, potted,
bare root, rhizomes and tubers, or seed. This is important because if the plants are
to be used in the splash zone where they may be partially covered with water, seed
of emergent aquatic plants will not germinate under water.
c.
Match the plant list against species availability, and do not assume that all species
advertised will be available in needed quantities.
d.
Order samples, if available, and verify plant condition and identification.
e.
Negotiate a flexible delivery schedule allowing for unpredicted delays in planting.
B-72
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