Types and morphologies of gully step pools of different process of formation in the Yuanmou dry-hot Valley

Step pools are micro-geomorphology hosted in gullies which are closely related to the channel erosion rate and hydraulic characteristics of runoff. These features are widely developed in the Yuanmou dry-hot Valley area of the Central Yunnan Plateau, China. In this paper, the morphological characteristics of different types of step pools in the Yuanmou dry-hot Valley were analyzed using analysis of variance and cluster analyses. The results show that: (1) step pools can be divided into differential, bedrock, barrier, and sub-erosion step pools based on the environment of development; the bedrock and differential step pools develop on a large scale, while barrier and sub-erosion step pools develop on a small scale; (2) the width and depth of the step, the height of the step, the width of the pool, and the depth of the step of the differential type, bedrock type, and sub-erosion type step pools exhibited a significant positive correlation (P < 0.01); the height of the step and the depth of the pool of the barrier type step pools were significantly negatively correlated with the height of the step and the concave hole depth of the sub-erosion type (P < 0.01); (3) the differential type and undercurrent type step pools were seriously eroded. The study of the types and morphologies of gully step pools in the Yuanmou dry-hot Valley helps understand the formation and evolution mechanisms of erosion gullies and provides a scientific basis for monitoring and controlling soil erosion.