1.1 Q (Water Discharge)

• 1. Increasing or decreasing discharge to enact fluvial processes.

• 1.2 S (Slope)

  1. Changing the angle at which the flume lies.

• 1.3 Qs (Sediment Discharge)

  1.  Pushing more "sediment" to the top of the flume and grading the surface to allow for erosion.

• 1.4 Profile

  1.  The area of the flume.

• 1.5 Base Level

  1. Lowering or elevating the drain to change the base - level 

2. Fluvial Geomorphic Processes

Simulate and record your observations of:

• 2.1 Bed Erosion

  1. As flows continue, the bed is degraded and aggraded dependent on flow power and sediment availability.

• 2.2 Bank Erosion

  1. As the river is meandering, it cuts into the bank pulling sediment into the river.

• 2.3 Deposition

  1. As sediment moves, it gets deposited in different locations depending on flow stage, meanders, branching.

• 2.4 Sediment Transport

  1. Sediment transport is the overall movement of sediment down the system.

3. Fluvial Geomorphic Mechanisms

Simulate and record your observations of the specific manifestation of fluvial geomorphic processes as these mechanisms of adjustment:

• 3.1 Grain Size Sorting

  1. As flows increase and decrease, grain sizes are sorted. Higher flows moves larger and heavier sediment.

• 3.2 Meandering

  1. Meandering is achieved when the river is forcing turns, one after another into the floodplain.

• 3.3 Braiding

  1. Braiding occurs when flows are high enough to push over the bank, these side channels return to the main channel at differing locations.

• 3.4 Avulsion

  1. When a channel suddenly abandons its current channel and forms a new one.

• 3.5 Chute Dissection

  1. When a chute is formed between two meanders, this creates a shorter and quicker route that water favors to take.

• 3.6 Structural Forcing

  1. When any type of structure, trees, rocks, anthropogenic sources. Forces the river to deviate from its former course.

• 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?

  1. We were unable to produce a classic single-threaded meander. The sediment we used in the flume was not cohesive enough to allow for this classic to occur. If we had a cohesive element, like alfalfa sprouts, we could have produced a single threaded meander in this experiment. The controls we had available would be able to produce this, but it would not without some sort of cohesion.

4. Events

• 4.1 Small Flood

  1. Small floods moved a large amount of sediment within the channel, there was a good amount of over-bank flow. These floods pooled behind structure, caused braiding and meanders.

• 4.2 Big Flood

  1. Big floods pushed a huge amount of sediment across the whole flume. The large flood was more homogenous in sediment transport, while the small flood was more localized and intense in those locations.

• 4.3 Channel Realignment (Grading)

  1. Grading the channel was effective in getting the results we wanted, we were able to form many different channel types.

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

  1. Small floods were localized sediment movement with heterogeneity in the movement of sediment. We were able to see how this changed with a big flood. In a big flood, there was a lot of homogenous sediment movement, almost everything was affected in a similar fashion. 

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

  1. Yes, by changing the flow amount and structure input, we were able to observe each of these flow regimes. We were able to observe the sediment transport of these flows and record how sorting was done by each regime.

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

  1. Hyporheic flow was present in many locations, this caused head cuts and chute dissection. When groundwater was able to move and infiltrate, it opened many new channel heads and pulled them back until they met with the main or side channel they were associated with.

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

  1. This is where the most sorting happened, as flows dropped so did sediment. We were able to observe these processes and noticed where the most amount of sediment was being deposited as we gradually decreased the flow amount.