upstream fill

例句：

1. 1. The upstream fill was crucial in preventing the river from silting up.
   上游填充物在防止河流淤塞中至关重要。
2. 2. The engineer had to upstream fill the damaged section of the pipeline.
   工程师不得不上游填充管道受损的部分。
3. 3. The upstream fill helped stabilize the flow and prevent further damage.
   上游填充物帮助稳定了水流，防止了进一步的损害。