470
Upper Mississippi River Adaptive Environmental Assessment
models. One example was the stated need for sensitivity analysis of the sediment components of the
pool and system models. Participants also highlighted the need for the vegetation submodel to be
evaluated by people who are knowledgeable about
long-term dynamics and to be tested by compiling
and comparing model output with historical time
series data on vegetative cover. Similar statements
were made about the habitat and navigation submodels. Several workshop participants said that
they planned to work individually and with other
colleagues to assess various aspects of the model.
The U.S. Geological Survey's Environmental Management Technical Center has established a group
mailing list to facilitate communication among
model users: umrs-aea@emtc.nbs.gov
Scenario Development
Workshop participants identified a range of scenarios that they would like to explore using the
UMR AEA simulation model. They emphasized
the importance of exploring a full range of alternatives, noting that the computer model permits
low-risk, low-cost experimentation because it does
not require commitments to any alterations in the
physical world. The scenarios described next represent general categories of management alternatives identified by participants. In all these scenarios, a suite of indicators would be examined. These
indicators might include changes in pool volume,
time required to reach sediment equilibrium, vegetation changes, habitat suitability plots, economic
flood damage reductions, dredging costs, recreational boating, and fishing. Using the model to explore any specific scenarios would involve manipulating a few key inputs, while holding a large
number of other variables constant.
1. Basin-scale modifications of land use affecting
input of nutrients and sediments: an attempt to
determine how surrounding land-use practices
would affect aspects of water quality and sediment patterns in the river.
2. Pool drawdowns: water level manipulation to
restore more natural variation in water levels
through seasonal changes in stage height. Potential manipulations include a summer drawdown to dry out sediments and promote plant
growth and a fall increase in water levels to
flood low-lying areas so that fish and waterfowl
would have access to new plant growth.
3. Reduction of flood impacts: an attempt to use a
variety of floodplain management regulations
and physical structures to moderate flood impacts to developed areas.
4. Extremes: remove all river regulatory structures
to examine restoration options or significantly
increase river regulation to support increased
channel depth.
5. Physical modifications: variations include increasing spatial diversity by island construction;
adding, removing, or notching training structures and levees; dredging channels deeper; partitioning pools into more management units; and
creating nutrient and sediment trapping structures.
6. Improved shipping efficiency: modifications to
tows and barges, alternative lock schedules, and
larger locks.
31.6 Future Work and Next Steps:
Phase II
As described earlier, the AEA project for the Upper Mississippi River has two objectives. Considerable progress has been made on the first objective, developing an integrated science-based
understanding of the river as a natural system.
Computer simulation models at both a pool and
river system scale have been developed and reviewed by participants representing a wide range
of perspectives and expertise. Participants in the
January 1997 workshop recommended that the
UMR AEA go forward to the scenario exploration
phase after some additional modifications to the
model are completed. Phase I, the scoping of the
problem and model development, is now complete.
The next steps in the AEA process will explore
alternative ways of reconciling the competing demands made of the Upper Mississippi (Figure
31.7). Development ofrestoration options must be
articulated and explored. As testing of the river system and pool models proceeds, understanding will
grow. The process must balance precision with relevance; that is, the river system is far too complex
to capture entirely on any computer, so we must
confine ourselves to attempting to model the most
important factors in the key river processes and
uses. The goal of scenario building is sustainability. Sustainability is multifaceted, and each individual has unique weighting that he or she assigns
to various ecological, economic, and social issues.
The AEA attempts to provide truly open access to
information and devices to use information. All
vested interests are asked to contribute.
In phase II, the AEA process focuses on learning that sharpens distinctions and builds clarity as
it begins to probe for flexibility and irreversibili-
Upper Mississippi River Adaptive Environmental Assessment
models. One example was the stated need for sensitivity analysis of the sediment components of the
pool and system models. Participants also highlighted the need for the vegetation submodel to be
evaluated by people who are knowledgeable about
long-term dynamics and to be tested by compiling
and comparing model output with historical time
series data on vegetative cover. Similar statements
were made about the habitat and navigation submodels. Several workshop participants said that
they planned to work individually and with other
colleagues to assess various aspects of the model.
The U.S. Geological Survey's Environmental Management Technical Center has established a group
mailing list to facilitate communication among
model users: umrs-aea@emtc.nbs.gov
Scenario Development
Workshop participants identified a range of scenarios that they would like to explore using the
UMR AEA simulation model. They emphasized
the importance of exploring a full range of alternatives, noting that the computer model permits
low-risk, low-cost experimentation because it does
not require commitments to any alterations in the
physical world. The scenarios described next represent general categories of management alternatives identified by participants. In all these scenarios, a suite of indicators would be examined. These
indicators might include changes in pool volume,
time required to reach sediment equilibrium, vegetation changes, habitat suitability plots, economic
flood damage reductions, dredging costs, recreational boating, and fishing. Using the model to explore any specific scenarios would involve manipulating a few key inputs, while holding a large
number of other variables constant.
1. Basin-scale modifications of land use affecting
input of nutrients and sediments: an attempt to
determine how surrounding land-use practices
would affect aspects of water quality and sediment patterns in the river.
2. Pool drawdowns: water level manipulation to
restore more natural variation in water levels
through seasonal changes in stage height. Potential manipulations include a summer drawdown to dry out sediments and promote plant
growth and a fall increase in water levels to
flood low-lying areas so that fish and waterfowl
would have access to new plant growth.
3. Reduction of flood impacts: an attempt to use a
variety of floodplain management regulations
and physical structures to moderate flood impacts to developed areas.
4. Extremes: remove all river regulatory structures
to examine restoration options or significantly
increase river regulation to support increased
channel depth.
5. Physical modifications: variations include increasing spatial diversity by island construction;
adding, removing, or notching training structures and levees; dredging channels deeper; partitioning pools into more management units; and
creating nutrient and sediment trapping structures.
6. Improved shipping efficiency: modifications to
tows and barges, alternative lock schedules, and
larger locks.
31.6 Future Work and Next Steps:
Phase II
As described earlier, the AEA project for the Upper Mississippi River has two objectives. Considerable progress has been made on the first objective, developing an integrated science-based
understanding of the river as a natural system.
Computer simulation models at both a pool and
river system scale have been developed and reviewed by participants representing a wide range
of perspectives and expertise. Participants in the
January 1997 workshop recommended that the
UMR AEA go forward to the scenario exploration
phase after some additional modifications to the
model are completed. Phase I, the scoping of the
problem and model development, is now complete.
The next steps in the AEA process will explore
alternative ways of reconciling the competing demands made of the Upper Mississippi (Figure
31.7). Development ofrestoration options must be
articulated and explored. As testing of the river system and pool models proceeds, understanding will
grow. The process must balance precision with relevance; that is, the river system is far too complex
to capture entirely on any computer, so we must
confine ourselves to attempting to model the most
important factors in the key river processes and
uses. The goal of scenario building is sustainability. Sustainability is multifaceted, and each individual has unique weighting that he or she assigns
to various ecological, economic, and social issues.
The AEA attempts to provide truly open access to
information and devices to use information. All
vested interests are asked to contribute.
In phase II, the AEA process focuses on learning that sharpens distinctions and builds clarity as
it begins to probe for flexibility and irreversibili-