Geoscience Reference
In-Depth Information
plan should also indicate how modii cations
based on unforeseen conditions could be
accommodated.
Monitoring and evaluation
- Monitoring
and evaluation plans both during and beyond
the completion of the project need to be drawn
up. Periodic assessments to evaluate the health
and condition of a restored ecosystem must be
implemented (Society for Ecological Restoration
International (SERI) 2004).
Table 13-1.
Approaches and methods for wetland
restoration and enhancement.
Passive or Hybrid
Approaches
Active Approaches
• Landscape contouring
• Topographic excavation
• Breaching levees
• Dam & weir removal
• Rerouting roads &
embankments
• Increasing culvert size
• Reconnecting natural creeks
and inlets
• Restoring the hydro-period
• Plugging drainage ditches
• Removing spillways
• Bioengineering
• Species introductions
• Connecting wetland patches
through corridor connectors
• Restricting human
or livestock
access to wetland
• Natural fl oral and
faunal
recolonization
• Eliminating water
controls
• Allowing natural
fl ood events
13.5 Approaches to wetland restoration and
enhancement
Systematic wetland enhancement and restora-
tion projects have a relatively recent history.
Even so, a broad range of techniques have been
employed to restore and enhance the structure
and functions of wetland sites globally. Thus far,
resource and cost limitations have coni ned
wetland restoration efforts to North America,
Europe and other developed nations. However,
emerging research on artii cial wetlands from
Asian nations suggests such efforts are gaining
momentum across the developing world and
may be indicative of future trends (Zhang et al.
2010).
The scale and scope of many restoration and
creation projects often necessitate involvement
by governmental agencies, industry, larger land
trusts, and conservation organizations in such
undertakings. This is a trend observed across
the world and one in which multiple stakehold-
ers play increasingly important roles. Long-term
partnerships and scientii c exchanges between
such groups hold promise in advancing the
science of wetland restoration more rapidly.
Moreover, the scientii c dissemination of suc-
cesses from individual cases contributes to a
more robust understanding of the challenges
and solutions in such actions.
Given the complexity of biotic and abiotic
interactions dominating wetland environments,
scientists generally agree that complete restora-
tion rel ecting the diversity of life and processes
that typify an original wetland site before dis-
turbance is a most difi cult undertaking. Resto-
ration approaches and techniques implemented
are selected based on the nature of the problem
being addressed, the type of wetland and the
unique characteristics of the site itself. The
Interagency Workgroup on Wetland Restoration
(IWWR 2003) identii ed two principal ap-
proaches, active and passive, to wetland restora-
tion and enhancement (Table 13-1). In many
instances, however, it is a combination of the
two that works best to restore ecosystem
processes.
13.5.1 Active approaches
Active approaches to restoration and enhance-
ment involve physical engineering efforts which
may include signii cant alterations to the topo-
graphy, soil, and hydrology of a site. Such engi-
neering approaches may involve the use of
large earth-moving equipment to breach levees
and re-l ood marshes, or backi ll channels and
remove spillways to rebuild l oodplains and
allow overland l ows.
One of the more ambitious examples of such
an approach is currently being undertaken to
restore some of the original meandering l ows
of the Kissimmee River, which provides much
of the water to the Florida Everglades (see Fig.
3-13). During the 1960s the Kissimmee River
