1. Pre-Settlement Drainage Network of the Upper Sangamon River Basin, Illinois
Jacob Henden1 and Alison Anders2
University of Wisconsin Eau Claire1, University of Illinois Department of Geology2, Email questions to hendenjl@uwec.edu
Introduction Results Discussion
Methods
Rivers, channels, and lakes within a drainage basin are collectively called
drainage networks. Climate, geologic structure, and lithology, all influence
the formation of drainage networks. Humans also impact formation, often
on a more rapid time scale. We estimated the configuration of a
pre-settlement drainage network in order to gain a better understanding of
the network’s natural evolution.
Study Area
• The Upper Sangamon River
Basin, located in East Central
Illinois (Figure 1)
• Characterized by low-relief
topography produced by the
Wisconsin Episode of glaciation.
• Drainage ditches make the
modern channel network
significantly more expansive than
it was in the early 1800s*
Figure 1. Upper
Sangamon River
Basin (USRB)
and modern
channel network
Figure 2. 1800s GLO surveyed channels within the USRB shown in
A, alluvial soils within the USRB shown in B
Historic Map Estimate
• Obtained digitized
channels made from
early 1800s General
Land Office Surveys
(Figure 2A)
Soil Map Estimate
• Selected soils with
alluvium as a parent
material from
Natural Resource
Conservation
Service soil maps
(Figure 2B)
Estimate Comparison
• Analysis tools in
ArcMap were used
to compare
pre-settlement
channel estimates
A B
A B
Topography Analysis
• Areas were selected
that did not appear
to have natural
channels based on
LIDAR topography
and contour lines
(Figure 3)
Figure 3. Region within USRB with natural channels shown in A,
region without natural channels shown in B
Literature Cited
• The current channel network is 2 times more extensive than the alluvial soil estimate, and
3 times more extensive than the 1800s GLO maps estimate
• 82% of the mapped 1800s channels are within 50 meters of alluvial soils.
• 40% of the USRB appears to lack natural channels
• Less than 3% of mapped 1800s channels and alluvial soils are found within areas that appear
to not be channelized
Figure 4 On the left, the Upper Sangamon River Basin is shown with 1800s GLO surveyed channels and a highlighted layer
of soil that was formed in alluvium. On the right is the Upper Sangamon River Basin with the modern channel network
Figure 5. LIDAR topography of the USRB shown in A, Areas without natural channels shown in B, mapped 1800s channels
and alluvial soils shown in C. Acknowledgments
• We would like to thank the National Great Rivers Research and Education
Center for providing funding for this project, Rodger Windhorn, Dave
Grimely and Art Bettis for advice in soils interpretation, and Quinn Lewis for
providing data used for analysis
• Rhoads, B. L., Lewis, Q. W., & Andresen, W. (2015). Historical changes in
channel network extent and channel planform in an intensively managed
landscape: Natural versus human-induced effects. Geomorphology.*
• Understanding drainage networks is necessary to understand how water and
sediments are transported across a landscape
• Human impact on the drainage network of the USRB make the natural
evolution of the network more difficult to study.
• Using historic maps, soil surveys, and topographic data, we were able to
produce estimates of the pre-settlement drainage network that placed the
channels in similar locations.
• The results of this research are intended to help produce a model for how
drainage networks form in low-relief previously glaciated areas
Figure 6. Photograph of a natural channel within the Upper Sangamon River Basin
A B C