Definitions:

1.1 Q (Water Discharge) - The volume of water flowing through a given cross sectional area within a unit of time.

1.2 S (Slope) - The gradient of the flume box/valley bottom.

1.3 Qs (Sediment Discharge) - The volume of sediment being transported through a given cross sectional area within a unit of time.

1.4 Profile - The elevation change of a stream bed from headwater to mouth (base level).

1.5 Base Level - The elevation of a profile at which no more erosion can occur with the current flow regime. Often a waterbody or basin at the mouth of a river.

Processes, Mechanisms, and Floods

3.7 While meandering can be observed, were you able to produce a classic single-thread, meandering channel in any of your experiments? If so, explain how it occurred, if not, do you think it is possible with the controls you had at your disposal in this flume?

I was about to create a single meander bend after using plant toys to stabilize banks and shunt water directly into a very steep hillslope, but nothing truly and entirely meandering. The bend did start to migrate which was super fun to see! I think that it would be difficult to get a meandering stream with our flume set up for several reasons: (1) the grain size was much too coarse to get any sort of bank cohesion that would support an unconfined meander or protect point bars from dissection by chute channels (2) the flume sediment drains water too quickly to become saturated and generate a low-velocity baseflow that would allow fine sediments to be stored in point bars.

4.4 From what you did, what seems to be the role/impact of small flood vs. big flood?

The big flood caused major changes in planform and channel type. For example, the bottom of the site in the long video switched from a braid plain to a wide channel with very defined banks. There was also a major avulsion at the top of the site. The small flood had a large impact on within channel bars and some minimal bank erosion (typically structurally forced).

4.5 In your experimentation, did you observe overbank flows, bankfull flows and/or baseflow flows?

There were a few seconds of overbank flow at during the big flood at the bottom of the site before the channel realignment from braid plain to straight channel occurred. Once the channel was realigned, all the major channels were at bankfull until the end of the flood. There was no baseflow because the flume sediments didn't hold onto the infiltrated flow enough to create a sustaining water table, but if we're counting the lower pump level in between the big and small floods (0:56) then yes there was kind of a baseflow.

4.6 What role did hyporheic flow play in what you observed?

As I described about, the flume sediments are a very porous medium and water drains through the channel bed very quickly. This flume essentially creates a losing reach unless the bed sediment layer is extremely thin, then the metal bottom could facilitate some throughflow and/or baseflow.

4.7 What role did recession limb flows seem to play in what you observed?

The recessional limb flow seemed to erosionally define the banks and create chute channel dissections. I think this is because the lowering flow starts to interact more with bedforms that were submerged during the peak flow, and it starts to become more concentrated into smaller scale thalwegs which can erode those bedforms and bank toes.