31.5 Assessing the Model: Workshop 2
ulation model and electronic access to the model
were provided to participants in the second workshop.
31.5.1 Views of the River
The January 1997 workshop served in part to clarify the very basic ways in which people perceive
the Upper Mississippi River. The essence of these
perspectives can be captured as caricatures, which
are admittedly oversimplified, but also informative
representations of how people view the current status of the river. Each caricature typifies or exaggerates a different ecological process or structural
component, with economic and social implications
as well. Although not explicitly stated as such, at
least four different caricatures emerged during the
two phase 1 UMR AEA workshops.
The Tamed River
This perspective indicates that the hydrologic character of the river has been constrained and controlled by humans. The rhythms or cycles of water
flow and water depths have been dampened or
tamed. Spatial and temporal variation in hydrology
and other processes has decreased due to the regulated management associated with the lock and
dam system. Water levels and flows are controlled,
so the distribution of areas wetted over time has
been changed, with some areas staying wet longer
and others staying dry longer.
The Flattened River
This caricature refers to the loss of topographic diversity within the river corridor. The loss of topographic complexity is associated with changes in
the hydrologic patterns and sediment movement.
Sediment is accumulating in tributary deltas, many
off-channel areas, and portions of the main channel. Wind and wave action further reduce topographic diversity by flattening open water areas of
the river. This caricature also includes the results
of manual manipulation of sediment, as cases
where dredge and spoil placements from channel
maintenance have led to a decrease in topographic
diversity. This topographic homogenization has led
to a change in vegetation patterns and animal habitats.
The Beaded River
In this view, the braided, meandering river of the
past has been replaced by one with two distinct
467
characteristics, riverine and pooled areas. The area
downstream of a dam retains much of its riverine
character until it meets the impounded water upstream of the next dam, which creates lakelike habitat. No longer truly riverine, the current river is like
a beaded necklace, a set of pools connected by remnants of the preimpoundment river.
The Dirty River
Although not widely discussed at the two workshops, this metaphor focuses on human-induced
water quality changes associated with development and watershed modifications. A recent U.S.
Geological Survey report analyzes where and
how the river has become more eutrophic, either
from nutrient-laden runoff from land-use activities within the basin or from sewage plants along
the river. Increases in a suite of other contaminants
also contribute to this caricature.
Each of these caricatures suggests aspects of the
complexity of the river and can be used in part to
judge whether the model captures what is important about the way the river works. They also point
out how the river has changed and perhaps what
might be done to address these changes. As such,
they can also be useful in helping to identify
policy-relevant resource issues on the Upper Mississippi River.
31.5.2 Management Issues
The key issue for the ongoing AEA of the Upper
Mississippi is the search for flexibility in two sectors of the system, the ecological and the economic.
This assessment is searching for the flexibility both
between and within these two subsystems. That is,
the assessment seeks to identify policy and management options for reconciling economic and ecological goals. Nested within the range of scales of
geography over time are incredible opportunities to
address overriding economic and ecological concerns (Figure 31.6). The project entails a search for
win-win management opportunities that resolve
the issues related to river changes as described in
the previous metaphors.
The management-relevant ecological issues for
the Upper Mississippi appear to fall into two general categories: sediment distributions and habitat
restoration. Sediment distribution has been altered
in the tributaries and the mainstream river. Changes
in distribution are associated with changes in sediment input and changes in water flow. In the tributaries, upland practices have increased sediment
ulation model and electronic access to the model
were provided to participants in the second workshop.
31.5.1 Views of the River
The January 1997 workshop served in part to clarify the very basic ways in which people perceive
the Upper Mississippi River. The essence of these
perspectives can be captured as caricatures, which
are admittedly oversimplified, but also informative
representations of how people view the current status of the river. Each caricature typifies or exaggerates a different ecological process or structural
component, with economic and social implications
as well. Although not explicitly stated as such, at
least four different caricatures emerged during the
two phase 1 UMR AEA workshops.
The Tamed River
This perspective indicates that the hydrologic character of the river has been constrained and controlled by humans. The rhythms or cycles of water
flow and water depths have been dampened or
tamed. Spatial and temporal variation in hydrology
and other processes has decreased due to the regulated management associated with the lock and
dam system. Water levels and flows are controlled,
so the distribution of areas wetted over time has
been changed, with some areas staying wet longer
and others staying dry longer.
The Flattened River
This caricature refers to the loss of topographic diversity within the river corridor. The loss of topographic complexity is associated with changes in
the hydrologic patterns and sediment movement.
Sediment is accumulating in tributary deltas, many
off-channel areas, and portions of the main channel. Wind and wave action further reduce topographic diversity by flattening open water areas of
the river. This caricature also includes the results
of manual manipulation of sediment, as cases
where dredge and spoil placements from channel
maintenance have led to a decrease in topographic
diversity. This topographic homogenization has led
to a change in vegetation patterns and animal habitats.
The Beaded River
In this view, the braided, meandering river of the
past has been replaced by one with two distinct
467
characteristics, riverine and pooled areas. The area
downstream of a dam retains much of its riverine
character until it meets the impounded water upstream of the next dam, which creates lakelike habitat. No longer truly riverine, the current river is like
a beaded necklace, a set of pools connected by remnants of the preimpoundment river.
The Dirty River
Although not widely discussed at the two workshops, this metaphor focuses on human-induced
water quality changes associated with development and watershed modifications. A recent U.S.
Geological Survey report analyzes where and
how the river has become more eutrophic, either
from nutrient-laden runoff from land-use activities within the basin or from sewage plants along
the river. Increases in a suite of other contaminants
also contribute to this caricature.
Each of these caricatures suggests aspects of the
complexity of the river and can be used in part to
judge whether the model captures what is important about the way the river works. They also point
out how the river has changed and perhaps what
might be done to address these changes. As such,
they can also be useful in helping to identify
policy-relevant resource issues on the Upper Mississippi River.
31.5.2 Management Issues
The key issue for the ongoing AEA of the Upper
Mississippi is the search for flexibility in two sectors of the system, the ecological and the economic.
This assessment is searching for the flexibility both
between and within these two subsystems. That is,
the assessment seeks to identify policy and management options for reconciling economic and ecological goals. Nested within the range of scales of
geography over time are incredible opportunities to
address overriding economic and ecological concerns (Figure 31.6). The project entails a search for
win-win management opportunities that resolve
the issues related to river changes as described in
the previous metaphors.
The management-relevant ecological issues for
the Upper Mississippi appear to fall into two general categories: sediment distributions and habitat
restoration. Sediment distribution has been altered
in the tributaries and the mainstream river. Changes
in distribution are associated with changes in sediment input and changes in water flow. In the tributaries, upland practices have increased sediment