Figure 8. Representative examples of multi-stage tributary
response in Cases 3 (a) & 4 (b). Note, upstream positions always
experience relatively longer initial adjustment stages than downstream
positions, regardless of rainfall gradient. Grey shaded and white
regions show where initial and final steady states (SS) and different
adjustment stages are represented along the profile lengths, as
indicated across top axis. a) Shows a tributary located in a relatively
downstream position, 15 km from trunk outlet and downstream fromxsc after 300 kyr of transient adjustment in Case
3, where the initial adjustment stage is relatively short-lived. Despite
this, protracted adjustment creates a several-kilometer-wide adjustment
zone with relatively smooth but notable along-stream variations inksn . This pattern is subtle on the longitudinal
profile. b) Shows a tributary located in an upstream position, 45 km
from the trunk outlet and upstream from xsc after
1.725 Myr of transient adjustment in Case 4, where the initial
adjustment stage is long-lived. The initial adjustment stage reshapes
the entire profile prior to adjustment of the trunk profile, but no
transient knickpoints or other obvious topographic indicators of such
significant modification are present, with smoothly varying localksn values within 10% of the mean. Also, note
overadjustment means that the increase in channel steepness required to
reach steady state contrasts with net reduction in channel steepness
during transient adjustment.