ABSTRACT:

Lab material developed for GY320 at Colorado College. This exercise compares different formulations of bedrock erosion and the effects of each on landscape form, drainage network patterns, and long profiles. The comparison involves Fastscape, a simple stream power erosion model, and a stream power erosion model with sediment. The values of m and n can also be changes to switch from a shear stress to stream power model. A simulated landscape is run for 1 My with diffusion and the tested erosion model and the resulting topography, drainage pattern, and long profile is output. The model is run using the Landlab toolkit (https://landlab.github.io/#/) with the LinearDiffuser, FastScapeEroder, StreamPowerEroder, ErosionDeposition, FlowAccumulator, and DepressionFinderAndRouter components.

ABSTRACT:

Lab exercise developed for GY320 at Colorado College. This resource explores the landscape morphology during a phase of mountain building by examining how topography and erosion rates evolve over time. The rates of uplift, linear diffusion, and rock erodibility are all adjustable. The simulation is built using Landlab (https://landlab.github.io/#/) using the LinearDiffuser, FlowAccumulation, and FastscapeEroder components.

ABSTRACT:

This activity is designed for a sophomore-junior level geomorphology course and provides a toolkit for students to explore how rock erodibility, uplift, and stream power create landscapes. As these variables are changed, the resulting landscape - visualized as a DEM and as a hypsometric curve - are altered. Students investigate how landscapes develop in response to different rock types, tectonic settings, and climate, then use hypsometric curves from the Andes (Montgomery et al., 2001) to hypothesize what rock type, tectonic, and climatic settings led to the different curves. The landscape evolution model is built using the LandLab component library (http://landlab.github.io/#/). Initial elevations are set using a random roughness grid. Diffusion, stream power erosion, flow routing, and a precipitation generator are simulated using pre-existing toolboxes in Landlab. Diffusion and erosion only occur when a storm in generated; otherwise the landscape remains static. All input parameters are called out in the Jupyter notebook rather than in a separate text file so that students can easily change one or two parameters at a time. The model output is two figures; one a digital elevation model of the landscape in planview and one a hypsometric curve of the landscape. No further output is saved or exported, but students are encouraged to record model input parameters and output in their lab assignment. After using the LandLab model, students discuss their initial predictions against their model results. Knowledge is tested using hypsometric curves from the Andes, where students must use the curve to hypothesize what the landscape conditions are (uplift, climate, rock erodibility).