Environmental Engineering Reference
In-Depth Information
10. Cost thresholds and unit costs for restoration and stewardship will decline
as larger scale ecosystem management strategies are used, rather than task-
oriented and smaller scale interventions.
EXAMPLES AT SCALE
This section provides two North American project examples and some associated
information we used to develop principles of large-scale restorations. An overview
of each project with more detailed sources of additional information and data is
cited in the references. These case studies are reasonably typical North American
examples of large-scale restorations. However, these are also emblematic of what can
be achieved when there is a common cultural context and a vigorous support infra-
structure. It should not be assumed these techniques and results can be transplanted
to Iraq easily. These case studies offer examples of the kinds of hydrological, biotic,
and technical issues that apply in North America. We suspect the same biotic prin-
ciples will apply in Iraq, but that the limiting factors associated with arid climate and
a damaged marsh Arab culture will influence the achievable outcomes.
The Red River of the North in Minnesota is an example provided to illustrate
basic relationships between wetland hydrology, land use, and the potential influ-
ences on the achievable biodiversity and productivity in wetland restorations in
large riverine basins. The Kankakee Sands wetland restoration in Indiana illus-
trates the pragmatic design process and steps used to restore a 7,300 acre drained
wetland basin.
RED RIVER OF THE NORTH, MINNESOTA
U
nderstanding
the
W
atershed
C
ontext
for
W
etland
r
estorations
The Red River basin upstream from Winnipeg and glacial Lake Winnipeg has a drain-
age area of about 45,000 square miles. This includes 17,806 square miles (4,611,833 ha)
in Minnesota, 20,820 square miles (5,392,472 ha) in North Dakota, 573 square miles
(148,409 ha) in South Dakota, and the balance (about 5,800 square miles [1,502,225
ha]) in Manitoba. Similar to the Tigris
-
Euphrates system in Iraq, the Red River of the
North descends from a set of upper subwatersheds to a very flat plain that once sup-
ported vast tracts of flood plain marshes and forested wetlands. Between European
settlement and 1970, the majority of these wetlands (85 percent) were drained for
annual crop agriculture; the flood-attenuating natural wetlands disappeared largely
from the system. The result has been a recent history of devastating floods. The proj-
ect summarized here is the attempt by Minnesota agencies, farmers, and the public at
large to understand how to ameliorate these forces to improve all aspects of this large
riverine system. Unlike most riverine wetland restoration studied in North America,
this is a rural watershed (≥ 90 percent in agriculture) physically similar to the Iraqi
system, but without a montane origin or in a similar arid landscape.
The Red River basin in Minnesota is shown on the shaded relief map in Figure 9.1.
To allow for direct comparison, the horizontal and vertical scales are consistent for
all cross-sections.
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