Sand Bar Flushing over Gates #20~22 March 15

Sand packs were still placed on the west side gates (#21~24). Actually, all gate upstream were covered with at least 1 ft deep sediment deposition.

Several questions and uncertainties are:

1. What makes sand bars move downstream quickly? Recently we did piano-like opening, and fully opening less than one day for surveying.
2. It seems like all gates are covered with sand pack now. Where these sands (sediments) came from? Transported from far upstream or just relocated from near diversion gate?
3. If these sands came from upstream, what volume and moving direction and speed can be?
4. With gate opening, how quickly we can flush these sand packs (not only on the gate, maybe 10 ft upstream of gates)?

Test gate opening suggestion for the question #4 above:

1. Measure sand bar depth from the gate concrete lining for gates #19~24,
2. Open gate #1~5 to keep decent upstream water depth during this test,
3. Open gate #19 for 30 min only, and then close, surveying sand bar depth (10 ft upstream gate),
4. Open gate #20 for 1 hr only, and then close, surveying sand bar depth,
5. Open gate #21 for 1.5 hr only, and then close, surveying sand bar depth,
6. Open gate #22 for 3 hr only, and then close, surveying sand bar depth.

The gate opening time will vary depending on the sand bar flushing.