Recent Channel-Migration Rates of Selected Streams in Indiana (1998-2011)

An investigation was completed to document recent
(circa 1998 to 2011) channel-migration rates at 970 meander
bends along 38 of the largest streams in Indiana. Data collection was completed by using the Google Earth TM platform and, for each selected site, identifying two images with capture
dates separated by multiple years. Within each image, the
position of the meander-bend cutbank was measured relative
to a fixed local landscape feature visible in both images, and
an average channel-migration rate was calculated at the point
of maximum cutbank displacement. From these data it was
determined that 65 percent of the measured sites have recently
been migrating at a rate less than 1 ft/yr, 75 percent of the
sites have been migrating at a rate less than 10 ft/yr, and while
some sites are migrating in excess of 20 ft/yr, these occurrences are rare. In addition, it is shown that recent channelmigration activity is not evenly distributed across Indiana.
For the stream reaches studied, far northern and much of far
southern Indiana are drained by streams that recently have
been relatively stationary. At the same time, this study shows
that most of the largest streams in west-central Indiana and
many of the largest streams in east-central Indiana have shown
significant channel-migration activity during the recent past.
It is anticipated that these results will support several fluvialerosion-hazard mitigation activities currently being undertaken
in Indiana.