Purpose

How to predict gully erosion rates was one of the most important issues at present. A model implemented in the Channel Hillslope Integrated Landscape Development (CHILD) model based on the shape factor (S_f) of the plunge pools, which successfully predicted the headcut retreat rates over a long timescale. But whether this model was also valid in the short-term scale? What factors affected the prediction effects of the model? These issues still need evaluation.

Material and method

Four gully head plots with consistent initial topography and soil types were constructed for conducting in-situ scouring experiments with different flow discharges. Eighteen tests were conducted in each plot to monitor the plunge pool growth and headcut retreat rates using an unmanned aerial vehicle (UAV) to create high-precision topographic data.

Results and discussion

The topographic parameters of the plunge pools generally increased with scouring duration and were strongly correlated with the total runoff energy consumption (0.55 < R² < 0.92, P < 0.01). In contrast, headcut retreat was an intermittent process that suddenly migrated in a short time after relatively long stable periods lasting from 20 to 130 min. The relationships between the headcut retreat rates and total energy consumption were weaker than those with the plunge pools.

Conclusion

As the timescale shortened, the contribution of mass failure due to gravity to headcut migration significantly increased, leading to the pool effects of the model to influence the prediction of the gully headcut retreat rates, which assumed that flow hydraulics were the key dynamics.

中文翻译：

---

基于干热河谷原位实验的短期尺度沟渠退修模型的验证

目的

如何预测沟壑侵蚀率是目前最重要的问题之一。在通道山坡综合景观开发（CHILD）模型中基于瀑布池的形状因子（S _f）实现的模型，该模型成功地预测了很长一段时间内的割草率。但是，该模型在短期内是否也有效？哪些因素影响了模型的预测效果？这些问题仍然需要评估。

材料和方法

构造了四个具有一致的初始地形和土壤类型的沟渠头图，以进行具有不同流量排放的现场冲刷实验。使用无人飞行器（UAV）在每个地块中进行了18个测试，以监测突降池的增长和顶切撤退速度，以创建高精度的地形数据。

结果和讨论

冲刷池的地形参数通常随着冲刷持续时间的增加而增加，并且与总径流能耗密切相关（0.55 < R ² <0.92，P <0.01）。相比之下，后撤是一个间歇性过程，经过20到130分钟的相对较长的稳定时间后，在短时间内突然迁移。切头后退速率与总能耗之间的关系要比跳水池弱。

结论

随着时间的缩短，重力引起的质量破坏对顶切偏移的贡献显着增加，导致模型的池效应影响了沟顶切入速率的预测，这假定水力是关键的动力学因素。