ABSTRACT
Single-thread rivers flowing through peat are as sinuous as classical alluvial meandering rivers, but have notably different planforms. Rivers in peat have straight segments alternating with sharp bends, as opposed to their more gently curving counterparts. Building on work in Indonesia and the Kushiro Peatlands of Japan, we characterize the statistics of bend shape in 5 nearly pristine peatland rivers in Siberia, Brazil and Indonesia, in terms of the probability density function of dimensionless curvature. Results are compared with 5 nearly pristine alluvial meandering rivers. We show that peatland rivers have significantly larger lengths of reaches with very low curvature (nearly straight) than alluvial rivers. We hypothesize that the formation of local “hard points” in peat may be responsible for the angular shape of river bends.
