Environmental Engineering Reference
In-Depth Information
• Survival of a percentage of plantings (or set amount of cover) for one growing season (i.e.,
one summer in North America) after installation
• Survival of a percentage of plantings (or set amount of cover) for one full year after
installation
• Survival of a percentage of plantings (or set amount of cover) for two or more growing
seasons (i.e., two summers in North America) after installation
• Survival of a percentage of plantings (or set amount of cover) for two complete growing
seasons after irrigation has ceased (assuming that plantings are irrigated for three years, this
results in a requirement for a certain agreed-upon level of plant survival for at least five
years after plant installation)
We find it is easiest to divide the plant establishment period into three phases: (1) the first year
immediately after plant installation, (2) the second year following plant installation until the ces-
sation of irrigation (assuming that some or all of the plantings are irrigated), and (3) the remaining
years of the plant establishment period during which there is no irrigation of plantings. Activities
associated with the plant establishment period include the following:
• Maintenance of infrastructure (e.g., perimeter fencing, signage)
• Care of individual plantings (e.g., maintenance of plant protection, maintenance of weed
protection, weeding around plantings)
• Elimination of unwanted ponding occurring around plantings
• Irrigation of plantings and maintenance of the irrigation system
• Weed management throughout the project site
• The control of exotic invasive plant and animal species
• Any necessary remedial erosion control
• Removal of any debris
It is important to conduct frequent periodic site inspections for maintenance needs throughout
the establishment period. A log should be kept documenting all site visits and maintenance ac-
tivities. This could help in identifying design modifications for future projects or project phases
and will also be valuable in estimating the time and materials required for maintenance associated
with future restoration projects.
The first full year after project installation is generally the most critical time for a restoration
project involving plantings (especially the first growing season). In drier regions, or in areas with
little or no rainfall during part of the year, plantings are generally irrigated. Typically during this
period dead, dying, or unhealthy plants are replaced and plant mortality is closely monitored. We
feel that it is easiest to require 100 percent survival of all individual plants (excluding unrooted
woody cuttings) at the end of the first growing season together with the installation of new plants
for all failed plantings. Requiring less than 100 percent survival requires a count of plants to estab-
lish meeting some criteria that is less (e.g., 80 percent survival). This can be very time consuming.
We also found, prior to implementing this policy, that sites had mortality that just met the
needed goal. In many cases, there would be large areas with high mortality. These open areas were
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