The drainage basin can increase its area and extend its channels by landslides at the edge of the network; by headward erosion; by the extension upslope of underground pipes; and by rill formation. See Coulthard and Van De Wiel (2007) Geomorph. 91, 3–4 on self-organization in drainage basin evolution, and Sagri et al. (2007) Geomorph. 94, 1–2 on tectonics and drainage basins.
Subjects: Earth Sciences and Geography.