Flow Patterns and Morphological Changes in a Sandy Meander Bend during a FloodSpatially and Temporally Intensive ADCP Measurement Approach
Petteri Alho; Elina Kasvi; Eliisa Lotsari; Leena Laamanen
https://urn.fi/URN:NBN:fi-fe2021042716756
Tiivistelmä
The fluvio-geomorphological processes in meander bends are spatially uneven in
distribution. Typically, higher velocities and erosion take place near the outer bank beyond the
bend apex, while the inner bend point bar grows laterally towards the outer bank, increasing the bend
amplitude. These dynamics maintain the meander evolution. Even though this development is found
in meandering rivers independent of soil or environmental characteristics, each river still seems to
behave unpredictably. The special mechanisms that determine the rate and occasion of morphological
changes remain unclear. The aim of this study is to offer new insights regarding flow-induced
morphological changes in meander using a novel study approach. We focused on short-term and
small-spatial-scale changes by conducting a spatially and temporally (daily) intensive survey during
a flood (a period of nine days) with an ADCP attached to a remotely controlled mini-boat. Based on
our analysis, the flood duration and the rate of discharge increase and decrease seems to play key
roles in determining channel changes by controlling the flow velocities and depth and the backwater
effect may have notable influence on the morphological processes. We discuss themes such as the
interaction of inner and outer bend processes and the longer-term development of meander bends.
Kokoelmat
- Rinnakkaistallenteet [19168]