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Entropy-based Model for Gully Erosion - A combination of probabilistic and deterministic components.
P H L Alencar1, A A F Simplício2, J C de Araújo3
1Technical University Berlin, Institut of Ecology, Ernst-Reuter-Platz 1, 10587 Berlin, Germany; Federal University of Ceará, Departament of Agricultural Engineering, Campus do Pici Fortaleza, Brazil.
The Science of the Total Environment
|May 4, 2022
Summary
A new gully erosion model, based on net shear stress, accurately predicts erosion rates and sediment yield. This tool aids planners in assessing gully impacts on land and water resources.
Area of Science:
- Environmental Science
- Geosciences
- Hydrology
Background:
- Gully erosion poses significant threats to ecosystems, causing land degradation and impacting water resources.
- Understanding gully evolution and developing accurate models remain challenging due to scarce knowledge.
- Gullies are primary sediment sources with rapid development, exacerbating environmental damage.
Purpose of the Study:
- To introduce a novel gully erosion model based on net shear stress principles.
- To develop and validate a new equation for calculating hydraulic shear stress using the principle of minimum cross-entropy.
- To assess the model's performance in predicting long-term erosion rates and sediment yield in real-world gully impacted areas.
Main Methods:
- A new gully erosion model was developed using the net shear stress concept (hydraulic shear stress minus critical shear stress).
- Hydraulic shear stress was calculated using a novel equation derived from the principle of minimum cross-entropy, validated with laboratory data (Nash-Sutcliffe Efficiency = 0.95).
- The model was implemented and tested in three locations with catchment areas from 0.01 to 10 ha, utilizing Unmanned Aerial Vehicle (UAV) and Structure-from-Motion (SfM) for data collection.
Main Results:
- The novel gully erosion model demonstrated successful estimation of long-term erosion rates with an efficiency of 0.77.
- The model's performance was validated across diverse catchment areas, indicating its robustness.
- The developed hydraulic shear stress equation showed high accuracy when compared to existing laboratory measurements.
Conclusions:
- The proposed gully erosion model provides a reliable tool for assessing erosion, sediment yield, and channel geometry.
- The model is recommended for use in catchments up to 8 ha, offering valuable insights for environmental management.
- This research contributes to a better understanding of gully erosion dynamics and provides practical applications for stakeholders and planners.
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