Friday, June 21, 2019

Gravel Tongue Draped into The Snake River Canyon

I was going through some pictures of the Snake River canyon through the southeastern Washington Palouse. The four dams on the lower Snake have been the subject of ongoing legal wrangling and policy debate. One big issue that may be under appreciated by some is the transport infrastructure and economy of the dry land wheat on the high plains above the canyon. I have previously touched on the subject of the Snake River and wheat transport (getting-wheat-to-river and mayview-tram-snake-river). There is no getting around the damage these dams as well as the dams in Hells Canyon have done to salmon populations. There is also no getting around how important the dams are for wheat transport. There is no good solution, or if there is, it will be costly. Indeed the existing circumstance has been costly.

The above said, I was looking at a picture of a grain loading facility on the south side of the Snake River just a bit upstream of the confluence with the Palouse River.  

Tongue of gravel descending slope across the Snake River from the grain facility

The facility is located on huge ice age flood bar that formed when the largest flood spilled across the Palouse from Spokane, completely filled the Palouse River valley and spilled out of the Palouse and into the Snake, permanently altering the course of the Palouse River (palouse-falls), and flooded into the Snake River canyon at this location. The flood completely filled the Snake River Canyon and due to the restriction at Wallula Gap water backed up the Snake all the way to Idaho (ice-age-floods-dem-and-lake-lewis).

The tongue of gravel on the slope shown above was from one of the spill over routes of flood water into the Snake River Canyon. It is the easternmost of the spill routes from the ice age flood. The togue of gravel descending down the slope is a rather unique feature. Lidar imagery of the canyon captures this feature rather well.

One more example of the need to reorient one's thinking when in ares impacted by the ice age floods. 

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