Evolution of rill networks on soil - mantled experimental landscapes driven by rainfall and baselevel adjustments

Experiments were conducted using a soil-mantled flume subjected to simulated rain and downstream baselevel lowering to quantify the evolution of rill networks. Results show that: (1) headcuts formed by baselevel lowering were the primary drivers of rill incision and network development, and the communication of this wave of degradation occurred very quickly through the landscape, (2) rill networks extended upstream by headcut erosion, where channels bifurcated and filled the available space, (3) rill incision, channel development, and peaks in sediment efflux occurred episodically, linked directly to the downstream baselevel adjustments, and (4) sediment discharge and rill drainage density approached asymptotic values with time following baselevel adjustments despite continuous application of rainfall. These findings have important implications for the prediction of soil loss, rill network development, and landscape evolution where headcut erosion can occur.