Studied by 38 peoplewhat three factors will slowly change a channel's morphology?
geology, gradient, and valley formation
what four factors will quickly change a channel's morphology?
hydrology, sediment input, flow obstruction, and riverside vegetation
what is catchment vegetation?
vegetation that catches a lot of water during rainfall; affects runoff
what two factors are external controls of channel morphology?
climate and catchment vegetation
lane's balance
according to lane's balance, if water discharge and/or slope increase, what happens to the channel?
erosion
according to lane's balance, if sediment discharge and/or grain size increase, what happens to the channel?
aggradation
what are the two types of terraces?
fill and strath
fill terraces
indicative of large-scale aggradation that buries valley; occur in alluvium channels only
strath terraces
indicative of large-scale erosion (with some aggradation); requires rock uplift to occur (changes base level)
how do dams affect rivers? (3 ways)
trap sediment and water both; decreases both sedimentation and discharge downstream; leads to biotic impacts
how does modern ranching and farming affect rivers? (4 ways)
degrading and eroding of banks; weight of animals can cause failure in fine-grained floodplains; larger slump erosion in wetland streams; fine sediment enters and new geometry of river forms
how does logging affect rivers?
more erosion due to less soil cohesion and more runoff; lack of large woody debris (LWD) equals loss of anastomosing channels
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