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Plenary session
Aquatic Systems in Changing Landscapes
IMMORTAL RIVER: THE UPPER MISSISSIPPI IN ANCIENT AND MODERN TIMES
Calvin R. Fremling, 1383 Gilmore Valley Road, Winona, MN 55987 e-mail: cfremlin@hbci.com
Abstract: Glacial meltwaters incised the 500-foot deep Upper
Mississippi River Valley through sedimentary rocks of the Paleozoic Plateau, yet La Crosse
lies within a remarkable area about the size of Denmark, missed by all glaciers. Viewing
the rugged blufflands from the river, explorers thought the river was flanked by
mountains; but there are no mountains or hills, only valleys. Prehistoric peoples utilized
the river for over 11,000 years, and Europeans and Americans exploited its furs for over
200 years. Soon after the first steamboat went up the river in 1823, the Corps of
Engineers began to channelize the river for navigation, first with 4 ½ -foot and 6-foot
channels until 1912, then with a 9-foot channel completed during the economic depression
of the 1930s. Early projects employed wing dams and closing dams to constrict the river.
The 9-foot channel was achieved by 29 locks and dams, supplemented by dredging. The
projects profoundly impacted the ecology of the river and its valley. Navigation interests
and the Corps of Engineers want to increase barge traffic by improving and enlarging the
locks and dams, while environmentalists fear the river will become a barge canal.
Railroads fear the competition.
Calvin "Cal" Fremling: Dr. Fremling has studied the
Mississippi River for more than 45 years as a teacher, researcher, hunter, fisherman,
historian, amateur geologist, and photographer. He is familiar with the entire 2300 miles
of the Mississippi, and knows some sections very well, especially the labyrinth of
backwaters near his home at Winona, Minnesota. Cal received his Ph.D. in Zoology from lowa
State University in 1959 and was Professor of Biology at Winona State University until his
retirement in 1991. He has devoted his retirement to writing about the Mississippi.
LANDSCAPES' REFLECTIONS IN THE WATER: AGRICULTURAL LAND USE CHANGES FROM
BIOGEOCHEMISTRY TO CONSERVATION
John A. Downing, Iowa State University, Department of Animal Ecology, 124 Science II,
Ames, IA 50011-3221, e-mail: downing@iastate.edu
Abstract: When I returned to the Great Plains after two decades of
working on Canadian lakes, I found an environment that had been greatly changed. Although
past decades saw improvements in point-source pollution control, the new century belongs
to non-point problems. Agriculture alters landscapes on an unprecedented scale. I
therefore concentrate on recent analyses of impacts of agricultural land use, drawing from
biogeochemical, hydrological, geographical, limnological, and biological data and analyses
to illustrate the repercussions of landscape alteration. Such changes as 1 mg/L total P in
streams, 100 mg/L suspended solids in lakes, rain nearly saturated with Si, light-limited
production due to silt transport, and greater than 50% decadal declines in state-wide
mussel richness are among the significant challenges offered when working in significantly
altered landscapes. Since the landscapes are changing, so too must we. Aquatic ecology
assumes new excitement when we are asked not only to understand or predict, but also to
manage and restore.
John Downing: Dr. Downing is a native Iowan, raised in North Dakota
and Minnesota. He arrived at Iowa State University in 1995 after having studied and worked
in Canada for several years. His current research interests include limnology,
biodiversity, the maintenance of population viability, biogeochemistry, the ecology and
production of resource organisms, and global ecology. He studies freshwater mussels,
marine mussels, littoral zone plants and animals, terrestrial and aquatic mammals, and a
variety of other organisms. He teaches courses in Aquatic Ecology, Ecological Resource
Management, Aquatic Invertebrate Ecology, and the spatial aspects of Precision Resource
Management.
HUMAN-INDUCED EROSION AND SEDIMENTATION IN THE DRIFTLESS AREA OF THE UPPER MISSISSIPPI
RIVER VALLEY
Stanley W. Trimble, University of California, Los Angeles, Geography Department, 1255
Bunche Hall, Box 951524, Los Angeles, CA 90095-1524, e-mail: trimble@geog.ucla.edu
Abstract: The pre-European landscape of the Driftless Area featured a
mosaic of prairie and forest, deep, well-developed soils, and clear, narrow,
well-modulated streams populated with brook trout. European agriculture generally began
during the first half of the 19th century. By the turn of the century, the hydrologic
buffering capacity of soils had been greatly diminished by cultivation and grazing so that
flooding, erosion and sedimentation were greatly increased. Over time, a "wave"
of sediment moved downstream with much of the sediment coming from the stream channels
which tended to widen greatly. By the 1920s and 30s, many main valley floodplains were
aggrading at rates of up to 15 cm per year. Roads, bridges, farms and villages were
literally buried. Most of this historical sediment still remains within basins as
colluvium and alluvium with deposits up to 5 m deep in lower reaches. The brook trout had
mostly disappeared by the late 19th century and by the 1920s, only stocked brown trout
could survive the flooding, high sediment concentrations, decreased baseflow, and higher
water temperatures. Soil conservation measures implemented during the 1930s, 40s and 50s
had strong effects by the 50s and 60s and both erosion and sedimentation rates were
greatly decreased. Present sedimentation rates are only about 5% of the highest rates.
Moreover, floods have greatly decreased (as evidenced by new, lower floodplains built in
the once-eroded upstream channel reaches), baseflows have increased, and water quality has
improved. The result is that the diagnostic brook trout can now reproduce and thrive along
many reaches. While some tributary reaches have been given fish structures and rip-rap,
such reaches are only slightly more stable than non-treated reaches. With the curtailment
of upland erosion rates, clearer, "sediment-hungry" streams have eroded sediment
from banks, moving it further downstream, the whole process again moving downstream as a
wave. This legacy of stored and sometimes-remobilized sediment has helped maintain
downstream sediment yields at high levels, but not as high as formerly. Additionally,
reversion of riparian areas to forest apparently increases long-term channel erosion and
downstream sediment migration. Streams and floodplains in these far downstream areas
continue to aggrade, and they may be considered to be locked into their own history, a
legacy of historically poor land use with its attendant effects.
Stanley Trimble: Dr. Trimble is Professor in the Department of
Geography and Institute of Environment, UCLA. His interests include historical geography
of the environment and especially human impacts on hydrology including soil erosion,
stream and valley sedimentation, and stream flow and channel changes. His regional
interests are the humid U.S. and western and central Europe. Trimble was a research
hydrologist with USGS 1973-84, and has been a visiting professor at the Universities of
Chicago, Vienna, Oxford, London (University College), and Durham. He is joint editor of
Catena, an international journal of soils, hydrology, and geomorphology. His research
grants include a Fulbright to the U.K., and his publications are diverse including several
in Science. Most recently, he served on the NRC Committee on Watershed Management, and
continues to serve on committees concerned with the Upper Mississippi River, where he has
done research for 3 decades.
SOIL AND WATER CONSERVATION BEHAVIORS WITHIN THE UPPER MISSISSIPPI RIVER BASIN
Ted L. Napier, Ph.D., Professor of Resources Sociology and Environmental Policy,
Department of Human and Community Resource Development and the School of Natural
Resources, Ohio State University, 2120 Fyffe Road, Columbus, OH 43210, e-mail: napier.2@osu.edu
Abstract: Data were collected in the fall of 1998 and winter of 1999
from 1,011 land owner-operators within three watersheds in the upper Mississippi River
basin to assess farm production systems in use at the time of the data collection. Study
findings revealed that respondents had adopted a number of the soil and water conservation
production practices assessed in the study, however, they were also using numerous
production practices that could negate the benefits associated with use of conservation
practices. Examination of the correlates of conservation use behaviors strongly suggest
that public and private conservation programs commonly used to motivate land
owner-operators to adopt and use conservation production systems were not useful for that
purpose. Factors such as access to conservation programs, access to conservation
information, access to technical assistance, farming experience, personal characteristics
of the primary farm operator, characteristics of the farm enterprise, access to
communication systems, access to partial economic subsidies, and a host of other variables
frequently identified as influencing conservation behaviors were shown to be relatively
inconsequential for predicting adoption/non-adoption of conservation production systems
among study respondents. Study findings strongly suggest that traditional approaches used
to motivate land owner-operators to adopt and use conservation production systems may no
be longer appropriate. Alternative intervention strategies will be required in the future,
which will probably require more extensive use of public policies to motivate resource
managers to adopt and use conservation production systems.
Ted Napier: Dr. Napier is a professor of Resources Sociology and
Environmental Policy at The Ohio State University. Dr. Napier holds a Bachelor of Arts
degree in Economics and a Master of Arts degree in Economics and Sociology from Marshall
University. He earned his doctorate in the Sociology Department at The Ohio State
University. He is a Fellow in the International Soil and Water Conservation Society and
has been recognized via numerous awards by several professional societies for his
contributions to environmental studies. Dr. Napier has published extensively in the area
of soil and water conservation and technology transfer in agriculture.
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