ANALYSIS OF HISTORICAL SEDIMENTATION TRANSECT DATA FOR SIX PERMANENTLY MARKED 
RIVER MILE TRANSECTS IN POOL 22 OF THE UPPER MISSISSIPPI RIVER.

Joseph S. Lundh, Gary V. Swenson, U.S. Army Corps of Engineers, Mississippi 
River Project, PO Box 534, Pleasant Valley, IA  52767.


Sedimentation transects were established by the survey branch of the Rock Island 
District of the Army Corps of Engineers at or near most whole numbered river 
miles on the Upper Mississippi River from Lock and Dam 10 to Lock and Dam 22.  
The first transects were established in the 1890's in Pool 19.  The six 
transects studied (river mile 315, 316, 320.4, 321.5, 323.1, 324.1) were 
established in 1955 and resurveyed in 1974 to 1975.  The permanently marked 
transects crossed the river perpendicular to flow extending from levee to levee.   
Elevation and bathymetric measurements to the nearest tenth of a foot were 
collected at roughly 50 foot increments along the transects and also at major 
features (ridges, bank-line, water's edge).  Comparing the 1955 data to 1975 
values showed significant changes.  Even though the overall change in elevation 
for the transects was an average increase of 0.2 feet, summing changes by 
different geomorphic features provided varying results.  Features that increased 
in elevation include sloughs by an average of 2.8 feet, chutes by 1.4 feet, 
islands by 0.6 feet, and mainland by 0.7 feet.  The main channel and main 
channel border were the only features that decreased on average.  The portion of 
the transects that were land in 1955 that continued to be land in 1975 raised by 
an average of 0.9 feet.  Due to the dynamic nature of the river, these results 
can best be applied to the upper part of Pool 22.  Resurveying these and other 
transects in the future would provide better trend data.  Comparing more 
comprehensive sedimentation data to hydrologic trend data will help in 
understanding the fate of the river's backwaters and floodplain.  

Keywords:  sediment range, sediment transect, sedimentation, Mississippi River, 
land survey