ABSTRACT
Though sediment transport is an intrinsic part of the functioning of karst aquifers, this flux has not received the attention devoted to spring chemistry and discharge. The fluviokarst conduit system acts as a mixing chamber where sediments from multiple sources are sorted, rearranged, deposited, and discharged. Our best windows into this chamber are deposits in conduits and sediment discharged at springs. Long-term continuous and event-based monitoring at five karst springs in Pennsylvania show that fine-grained clastics move even during ordinary storms. In large storms, suspended sediment concentrations can increase orders of magnitude, and the rarely mobilized large fraction (cobble to boulder) moves as bedload. These processes are difficult to predict with similar storms giving rise to disparate responses, and system dynamics controlled by strongly non-linear relationships with thresholds.