Saturday, July 12, 2008

Mud or Sand?

I am in the midst of getting my Geology of the Green River class finalized. You always have to wait until the last minute to see what the water conditions are like. The past few years have seen lower than average water conditions. The good news is that the sand bars are numerous and camping is pretty easy...the bad news is that you paddle all day every day. This year could be different with the record snow pack last winter. Rivers have been running high but it looks like the discharge has been dropping off rapidly in the past week as the snow pack from last winter has about finished melting. This graph shows a 1000 cfs drop in discharge about every 60 hours. Of course this is a dam regulated river flow and we know we won't run out of water (which this graph might suggest) , the question is when will the river reach its regulated base flow of 1975 cfs?
If we have water levels greater than 3000 cfs, there might be a bit of mud to content with, in which case the class might spend even more time looking at modern day sediment and sediment transport down the river and on our sandals. If the water levels drop to closer to 2000 cfs, we will have more sand and more sand bars to play with.

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