Waterfall plunge pools experience cycles of sediment aggradation and scour that modulate bedrock erosion, habitat availability, and hazard potential. We calculate sediment flux divergence to evaluate the conditions under which pools deposit and scour sediment by comparing the sediment transport capacities of waterfall plunge pools (Qsc_pool) and their adjacent river reaches (Qsc_river). Results show that pools fill with sediment at low river discharge because the waterfall jet is not strong enough to transport the supplied sediment load out of the pool. As discharge increases, the waterfall jet strengthens, allowing pools to transport sediment at greater rates than in adjacent river reaches. This causes sediment scour from pools and bar building at the downstream pool boundary. While pools may be partially emptied of sediment at modest discharge, floods with recurrence intervals >10 yr are typically required for pools to scour to bedrock. These results allow new constraints on paleodischarge estimates made from sediment deposited in plunge pool bars and suggest that bedrock erosion at waterfalls with plunge pools occurs during larger floods than in river reaches lacking waterfalls.

中文翻译：

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瀑布水池中沉积物冲刷和基岩侵蚀的质量平衡控制

瀑布式跌水池经历沉积物堆积和冲刷的循环，从而调节基岩侵蚀、栖息地可用性和潜在危害。我们通过比较瀑布瀑布池 (Qsc_pool) 及其邻近河段 (Qsc_river) 的泥沙输送能力来计算泥沙通量发散，以评估水池沉积和冲刷泥沙的条件。结果表明，在河流流量较低时，水池充满了沉积物，因为瀑布射流的强度不足以将供应的沉积物负荷输送出水池。随着流量的增加，瀑布射流增强，使水池以比邻近河段更高的速度输送沉积物。这会导致沉积物冲刷下游池边界处的池和坝体。虽然在适度排放时水池可能会部分清空沉积物，池子冲刷到基岩通常需要重复间隔 >10 年的洪水。这些结果允许对沉积在跌水池坝中的沉积物进行的古排放量估计产生新的限制，并表明在比没有瀑布的河流河段更大的洪水期间，有跌水池的瀑布的基岩侵蚀发生在更大的洪水中。