The proliferation of dams since 1950 promoted sediment deposition in reservoirs, which is thought to be starving the coast of sediment and decreasing the resilience of communities to storms and sea-level rise. Diminished river loads measured upstream from the coast, however, should not be assumed to propagate seaward. Here, we show that century-long records of sediment mass accumulation rates (g cm⁻² yr⁻¹) and sediment accumulation rates (cm yr⁻¹) more than doubled after 1950 in coastal depocenters around North America. Sediment sources downstream of dams compensate for the river-sediment lost to impoundments. Sediment is accumulating in coastal depocenters at a rate that matches or exceeds relative sea-level rise, apart from rapidly subsiding Texas and Louisiana where water depths are increasing and intertidal areas are disappearing. Assuming no feedbacks, accelerating global sea-level rise will eventually surpass current sediment accumulation rates, underscoring the need for including coastal-sediment management in habitat-restoration projects.

自1950年以来，大坝的扩散促进了水库中的沉积物沉积，这被认为使沉积物海岸挨饿，并降低了社区对风暴和海平面上升的适应力。但是，不应假定从海岸上游测得的河流负荷减少，是向海传播的。在这里，我们显示了长达一个世纪的沉积物质量累积率（g cm ^-2  yr ^-1）和沉积物累积率（cm yr ^{-1）的记录}）在1950年之后在北美周围的沿海沉积中心增加了一倍以上。大坝下游的泥沙源弥补了因蓄水而损失的河流泥沙。除了迅速沉降得克萨斯州和路易斯安那州的水深在增加，潮间带的地区正在消失之外，沉积物在沿海沉积中心的堆积速度甚至达到或超过了相对海平面上升的速度。假设没有反馈，全球海平面上升的加速将最终超过当前的沉积物积累速度，从而强调了将沿海沉积物管理纳入生境恢复项目的必要性。