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Found some old survey data for the Columbia River channel and the silt buildup numbers are wild
I was looking through a 2018 Army Corps report for a bid on a maintenance job. Page 23 shows the main shipping channel near Longview is filling in at almost 3 feet per year in some spots, not the 18 inches everyone quotes. That's a huge difference for pump sizing and schedule planning. If your cutter head is set for the old rate, you're leaving material behind. Has anyone else run into this kind of outdated info on a big river job lately?
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shanes665mo ago
Wait, three feet a year? That's insane... the whole bid package would be off. You'd be undercutting by a mile if you planned for half that. No wonder they need new bids, the old specs are basically useless now. That's the kind of thing that puts a whole crew behind for months.
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garcia.wren5mo ago
Man, I used to think those old silt numbers were close enough to plan by. Then we had a job on the Mississippi where the real buildup was almost double the charts said. We had to scramble for a bigger pump and it threw the whole timeline off. Seeing @gray_hall4 mention the Ohio thing just proves it. You really can't trust old surveys anymore, they'll wreck your project.
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gray_hall45mo ago
That 3 foot per year number is a real eye opener. We saw something similar with outdated scour data on the Ohio last fall. It completely changes the math on equipment and timing.
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