Climate-Tectonic Controls on Drainage Divide Migration and Sediment Export
A completed landscape-evolution study testing how runoff and uplift gradients affect drainage-basin competition, local river capture, relief, soil storage, and sediment export.

Software compatibility
The source, retained results, figures, tests, and documentation use Landlab 2.11.0 with the pinned Python 3.14 environment. Other Landlab or Python versions require a new verification run.
Project definition
Problem statement
Drainage divides are dynamic boundaries. Unequal uplift and runoff can change channel competition, trigger local capture, alter relief, and redistribute sediment even when one summary divide coordinate appears stable.
The geology problem is to isolate these coupled controls in a transparent synthetic landscape and retain enough spatial, temporal, and numerical evidence to distinguish process response from plotting artefacts.
Project objectives
- Build a two-outlet synthetic landscape with soil, bedrock, channel incision, sediment transport, and hillslope diffusion.
- Compare balanced, runoff-gradient, uplift-asymmetry, and compound-forcing scenarios over 100,000 years.
- Measure basin area, outlet allegiance, capture events, relief, hypsometry, soil depth, and sediment export.
- Test all nine combinations of three runoff contrasts and three uplift contrasts.
- Check time-step convergence and retain reproducible tables, figures, tests, references, and documentation.
Project structure
Project components
Landscape model
Creates the deterministic terrain, opposing outlets, runoff field, uplift field, soil layer, and process components.
Scenario runner
Executes four primary scenarios with shared geometry, checkpoints, and reproducible parameters.
Capture analyser
Tracks core-node outlet allegiance, drainage-divide positions, basin areas, and local capture events.
Sediment analyser
Retains cumulative outlet export, soil depth, relief, hypsometry, profiles, and sediment budgets.
Verification layer
Runs the forcing matrix, convergence study, automated tests, dependency audit, document checks, and repository validation.
Methodology
Project workflow
- 01Define the landscape
A validated JSON configuration declares grid geometry, process parameters, forcing scenarios, runtime, checkpoints, and random seed.
- 02Route flow
Landlab resolves D8 drainage directions, accumulation, and outlet membership on the evolving surface.
- 03Evolve terrain
Uplift, stream-power erosion, sediment transport, and linear diffusion advance the landscape through time.
- 04Measure response
The workflow records divide, capture, basin, relief, soil, profile, and outlet-sediment evidence at fixed checkpoints.
- 05Compare and verify
Primary scenarios, the full forcing matrix, and time-step cases are plotted, tested, audited, and retained.
Demonstration scenario
The compound-forcing case changes the final outlet allegiance of 10 core nodes while the resolved median divide coordinate remains unchanged. The retained event, basin, profile, and sediment evidence shows why a single divide coordinate is insufficient for diagnosing local reorganisation.
Engineering
Tools and method
- Tools
- The project uses Python 3.14, Landlab 2.11.0, NumPy, Pandas, Matplotlib, Seaborn for subject analysis, simulation, and results.
- Terrain layer
- Landlab raster grids store surface elevation, soil depth, drainage area, receiver relationships, and boundary conditions.
- Process layer
- Priority flood routing, SPACE erosion and deposition, uplift, and linear hillslope diffusion drive landscape change.
- Experiment layer
- Python executes four long scenarios, a three by three forcing matrix, and three numerical-resolution cases.
- Evidence layer
- Pandas, CSV, JSON, and PNG retain time series, node states, profiles, event records, comparisons, and figures.
- Verification
- Twenty-one automated tests, branch coverage, dependency audit, Docker execution, document audits, and repository validation verify the delivery.
Testing
Evaluation
Evaluation measures
- Drainage-divide position and row-level migration
- West and east basin areas and captured core nodes
- Mean elevation, relief, and hypsometric integral
- West, east, and total cumulative sediment export
- Mean soil depth, maximum drainage area, and central profiles
- Response across the nine forcing combinations
- Relative differences across 125, 250, and 500-year steps
Project boundaries
- The landscape is synthetic and is not calibrated to a named catchment.
- Absolute erosion, capture, and sediment-export values depend on the declared geometry, grid, parameters, and process representation.
- The experiment does not include lithological heterogeneity, landslides, groundwater, vegetation, glacial processes, or field-calibrated climate histories.
- Application to a real basin requires field data, parameter calibration, uncertainty analysis, independent validation, and qualified geologists or geomorphologists.
Included
- 01Complete Python and Landlab source code
- 02Four completed 100,000-year landscape-evolution scenarios
- 03Nine-case runoff and uplift forcing experiment
- 04Three-case time-step convergence experiment
- 05Ten retained CSV evidence tables and eighteen generated figures
- 06Three attributed literature images
- 07Forty-five annotated references
- 08Twenty-one automated tests with 97.97 percent branch-aware coverage
- 09Complete project files, calculations, results, and analysis material in a private GitHub repository
- 1085-page project documentation in PDF and editable Word formats
- 113-page setup and usage guide in PDF and editable Word formats
Project record
No information is collected on this page.
- Permanent project ID
- GP-GE-1Y8L4TA
- Catalogued
- 21 Aug 2026
- Completed
- 28 Aug 2026
- Verified
- 28 Aug 2026
- Demonstration
- Included in repository
Handover
After purchase
- 01Payment is confirmed
The project is marked unavailable and cannot be purchased again.
- 02Repository access is granted
The buyer's submitted GitHub account receives access to the private repository.
- 03The purchase record is delivered
The certification sheet is prepared from the reviewed buyer details and sent privately by email.