Direct connectivity between upstream and downstream promotes rapid response of lower coastal-plain rivers to land-use change

Low‐relief fluvial systems that originate in the lower coastal plain and discharge into estuaries are common along passive margins. These watersheds are thought to be disconnected from their termini by floodplains, which buffer the sediment‐routing system by sequestration. Here, we present a detailed study of the Newport River, a typical lower coastal‐plain system, which reveals high connectivity between watershed and delta. Connectivity is measured as the time lag between initiation of a silviculture operation, which increased landscape erosion, and when the sediment appeared at the bay‐head delta. The time lag, measured from aerial photographs and sedimentation rates calculated from 210Pb‐ and 137Cs‐activities in cores from the watershed and delta, is