Lehigh University Hydraulics
Lab
Department of Civil and
Environmental Engineering
The Advanced Geomorphology class, in the Spring of 2000 with the cooperation with the CEE Dept constructed a flume in the upper tank of the Hydraulics Lab.
Here are some photos of the
flume construction and channels that were established during the trial
runs. The first experiments were to observe the effects of tributary
inputs of discharge and sediment on the hydraulic geometry of the trunk
channel.
In the Spring of 2001, Kurt
Frankel completed an independent study course in fluvial geomorphology.
Aided by Jordan Vaughn, the flume was re-designed and new exeperiments
were run to observe the effects of base level fall on a stable meandering
channel, with and without bedrock reaches. These three photos above
show the (l-r) the stable channel just before the base level fall, the
incising channel about 20 seconds into the base level fall, and the incising
channel 15 minutes into the base level fall.
A similar base level fall
experiment was run with vertically-bedded varved sediments inserted as
a simulated bedrock reach. These photos show the base level fall
knickpoint hung up on the "bedrock". Eventually, an inner gorge is
incised, leaving behind a strath terrace, clearly visible in the photo
to the right. Check out the thin mantle of sand as the terrace alluviam
atop the strath! The strath terrace dips upstream reflecting the
interaction and relative rates of downwearing and knickpoint retreat processes.