Bases: landlab.components.erosion_deposition.generalized_erosion_deposition._GeneralizedErosionDeposition

Erosion-Deposition model in the style of Davy and Lague (2009). It uses a mass balance approach across the total sediment mass both in the bed and in transport coupled with explicit representation of the sediment transport lengthscale (the “xi-q” model) to derive a range of erosional and depositional responses in river channels.

This implementation is close to the Davy & Lague scheme, with a few deviations:

• A fraction of the eroded sediment is permitted to enter the wash load, and lost to the mass balance (F_f).
• Here an incision threshold is permitted, where it was not by Davy & Lague. It is implemented with an exponentially smoothed form to prevent discontinuities in the parameter space. See the StreamPowerSmoothThresholdEroder for more documentation.ωω
• This component uses an “effective” settling velocity, v_s, as one of its inputs. This parameter is simply equal to Davy & Lague’s d_star * V dimensionless number.

Erosion of the bed follows a stream power formulation, i.e.,

Note that the transition between transport-limited and detachment-limited behavior is controlled by the dimensionless ratio (v_s/r) where r is the runoff ratio (Q=Ar). r can be changed in the flow accumulation component but is not changed within ErosionDeposition. Because the runoff ratio r is not changed within the ErosionDeposition component, v_s becomes the parameter that fundamentally controls response style. Very small v_s will lead to a detachment-limited response style, very large v_s will lead to a transport-limited response style. v_s == 1 means equal contributions from transport and erosion, and a hybrid response as described by Davy & Lague.

Unlike other some other fluvial erosion componets in Landlab, in this component (and ) no erosion occurs in depressions or in areas with adverse slopes. There is no ability to pass a keyword argument .SPACEerode_flooded_nodes

If a depressions are handled (as indicated by the presence of the field “flood_status_code” at nodes), then deposition occurs throughout the depression and sediment is passed out of the depression. Where pits are encountered, then all sediment is deposited at that node only.

A note about sediment porosity: Prior to Landlab v2.0 this component took a porositiy keyworkd argument . For an explaination of why it no longer does (including a mathematical derivation), see Pull Request 1186. If is passed to this component a value error will be raised.phiphi

Component written by C. Shobe, K. Barnhart, and G. Tucker.