Environmental Engineering Reference
In-Depth Information
inverts, roads, and other infrastructure elevations) represent an important design
consideration. Biological changes such as seed bank depletion and conversion to
agronomic and noxious weedy species can contribute significant cost and reduced
levels of restoration performance, and can lengthen the restoration period.
Innovative strategies for assessing seed banks, modifying hydrology, and plant-
ing and managing the land are important for success. For example, by understand-
ing the seed bank through least plot analysis, hundreds of thousands of dollars
were saved by eliminating significant seed purchases and reducing the cost of
wild harvesting those native plants projected to appear on their own from the
seed banks.
Agricultural herbicide residues and salinity from highway runoff were found to
affect the seed bank and planted native species growth and development greatly. In
locations with residual toxicity, soil amendments to chelate (change the chemical
form) helped restoration success. In arid regions, addressing salinization and toxic-
ity will be more important than in Indiana, where regular precipitation has helped
reduce this carryover effect (see chapters 17 and 20).
CONCLUSION
Restoration of the Iraqi mesomarsh ecosystems will be a very complex undertaking
informed by at least the following principles and needs.
•
The users—the “marsh Arabs”—must be a part of the planning and imple-
mentation from the beginning to the end of restoration efforts. These
peoples will be instrumental in the construction, use, and protection or
exploitation of the restored ecosystems. Any technical restoration program
that ignores the key role of these peoples and their cultures is much more
likely to fail than a program that places these people front and center. We
ought not to model ecological restorations on the ill-planned U.S. military
activities in postwar Iraq. The abject failures of U.S. policy since the end
of formal military combat should support the strategy of placing Iraqis in
charge of restoration programs, including prioritization of local projects
from the outset.
•
Data on the hydrological cycles of the rivers are essential. Understanding
the hydrological fluctuations and water qualities endemic to these systems
is fundamental to restoration.
•
Data on the survival and availability of plants in the seed bank of previously
drained areas are very important. Prerestoration efforts may include restor-
ing native plant nurseries as a prerequisite to successful restoration.
•
Water quality data for these river systems will be required. Restoration suc-
cesses may be influenced strongly by waste disposal practices upstream,
especially in Baghdad for human pathogens, or owing to toxic residuals
from decades of war. Such toxic agents as heavy metals, organophosphates,
organochlorines, oil, polycyclic aromatic hydrocarbons (PAHs), substrate
chemical stocks, and depleted uranium from military weapons are certain
to be common contaminants in Iraqi watersheds after combat. These will
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