Flume Observations

Flume Controls

The flume allows us to control multiple aspects that help us simulate fluvial processes. To control water discharge (Q), we use a control panel that alters the flow rate of the flume. To change slope we would need to change the high of the table legs where the water dispenses (head waters). Sediment discharge (Qs) is controlled by the flow rate or discharge. We can change the profile by alter flow rate and physically moving sediment around. To control base level flows, there is a plug at the bottom of the flume that we are able to rise and lower.

Panel to control flow rate

Table legs control slope

Plug to control base level

Fluvial Geomorphic Processes

IMG_1810.MOV

Bed Erosion and outer bank erosion

deposition.mp4

Inner bank deposition

IMG_1808.MOV

Sediment transport

Fluvial Geomorphic Mechanisms

Grain Size Sorting

Grain size used in flume. Red (smallest), black, white, yellow (biggest).

An example of grain size sorting with all grain sizes.

IMG_1813.MOV

Video of grain size sorting

structural depostion.mp4

In the above video we see a great example of structural forcing and how it affects the channel. As a result we can see deposition above stream of the structure.

chute and braiding.mp4

Here we can see two mechanisms at work, chute dissection and braiding. It makes sense that they would be able to occur in the same setting.

IMG_1836.MOV

Meandering as best as we could capture it, we dug the path out ourselves. The video is far longer than most others I took as I wanted to see if time had an effect on the meander.

avulsion.mp4

The avulsion we observed was a result of a flood event we created.

We were unable to create a classic, single-threaded meandering channel. They always were accompanied by braiding. I'm not sure if we would be able to create a single-threaded meander. I assume it would take more time and better sediment input from the "head waters" of the flume.

Events

IMG_1834.MOV

Small flood event resulting in flood plane usage, overbank flows and channel realignment (timestamp - 0:55).

IMG_1830.MOV

Large flood event - the river channel(s) are less dynamic when the discharge rates are so high. Things tend to just get wiped out.

IMG_1837.MOV

Channel realignment as facilitated by my classmates.

Analysis

What seems to be the roll/impact of small flood vs big flood?
- Smaller floods tend to result in a more dynamic river scape, while large floods reduce any kind of riverscape that might have existed before. Larger floods also move a large amount of sediment, stripping the land that was upstream and delivering it all downstream.
Did you observe overbank flows, bankfull flows and/or baseflow flows?
- We did observe overbank flows, bankfull flows, and base flows.
What role did hyporheic flow play in what you observed?
- There was a lot of hyporheic that created braided channels and avulsion to occur. It also aided in sediment transportation.
What roll did recession limb flow seem to play in what you observed?
- During the recession limb flows, we saw a lot more sediment deposition since the flow was beginning to reduce.

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