Karst conduit sinuosity as a driver of karst hyporheic exchange

It has recently been suggested by the authors that water from a flowing phreatic karst conduit can enter the surrounding permeable matrix, in an analogy to hyporheic exchange for streams. Within the matrix two consequences of this exchange are processing of conduit water chemistry and speleogenesis. Small-scale exchange to and from the conduit is promoted by hydraulic head variations created by the conduit wall topology, but there is also a larger scale exchange created by conduit sinuosity and axial conduit head gradients. Considering several types of sinuosity, we use mathematical modeling of conduit flow to drive 3D matrix flow and exchange, examining the patterns, rates, and residence times of exchange and the resulting implications for water chemistry and additional speleogenesis. Presenting results in terms of dimensionless numbers allows us to address karst conduits at different stages of development, and to assess the importance of sinuosity driven exchange in terms of diver-observable features in the larger conduits.