One of the sources for sediments that the river transports is the river bank. Banks that are composed of materials that are easily picked up by the water contribute more to the sediment load of a river than those that are composed of more cohesive materials. In a similar way banks that are steeper, higher, more convoluted, and more disturbed all contribute disproportionately more to the sediment load.
Erosion is a natural process. The moving water lets go of its energy through turbulence and erosion. In this way the river forms the riffles and pools, the bars and meanders, and the flood plains and oxbows that characterize it. You could give your students valuable experience in map reading by helping them to recognize river features on a map. The more detailed 7.5"x15" USGS quads work best. The Elizabethtown quad shows many of the features of the Boquet River.
The field study Streambank Erosion provides a worksheet for estimating the relative amounts of sediments given banks are likely to contribute to the river during a one year period. This is a wonderful exercise that combines experience in gathering data in the field and in the mathematical analysis of the data to provide meaningful results.