Various examples are provided related to high-resolution sediment sensing including, e.g., water depth and/or water velocity sensing. In one example, a sediment dynamics monitoring system for scour, erosion or deposition detection includes a fiber-optic distributed temperature sensing (FO-DTS) sediment dynamics monitoring device including a support structure; a FO cable providing continuous sensing along a length of the support structure; and a heating element collocated along the FO cable; a power controller configured to control heating of the heating element; and a DTS system that can measure a temperature profile along a length of the FO cable. An anomaly in the measured temperature profile indicates an interface surrounding the FO-DTS sediment dynamics monitoring device. interface can be a sediment-water interface or a water-air interface.