I've added extra sediment to the sediment input device twice now. It stopped flowing yesterday about 7 pm after we started the sediment feed at 3 pm. I left it overnight. Today I added sediment at 2 pm and at 6 pm. It appears that while sediment isn't being added to the system, the water flow digs a pit at the head of the channel and then prefers to take the channel closer to the seats in the classroom. When sediment is being added, the pit is first filled in, and then the water tends to take the straight channel.
One problem with the sediment feed is that the end with all of the sand in it sinks into the water-logged table. This makes the sediment stop going into the table earlier than it normally would. If we find a way to prop it up it would work for longer periods of time.
One problem we may run into soon is that we're running out of sediment to add to the table. I may go to Prof. Little's place tomorrow to help get some new sediment to add to the container. The bedforms are migrating well as long as sediment is being fed into the system. They are filling in one side of the channel (and there is a little bit of erosion on the other side of the channel!) but using up a lot of our sediment.
Martell and I were thinking that it might be good to decrease base level just a tiny bit. Not much at all, but with the water table high enough that much of the table is flooded, it's hard to get any bank erosion in the main channel we're hoping will migrate. A very small drop in base level may restrict the water more to the channel. This will hopefully increase erosion and deposition in that channel, and we won't lose as much sediment and water flow to other parts of the table. If that doesn't yield good results after a few days, then maybe Wednesday or Friday of this next week we may want to re-start the table with a sediment feed from the very beginning.
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