Effect of Rill Development on Slope Erosion and Sediment Yield Based on Stereophotogrammetry Technology

Rill erosion is an important kind of slope erosion and the main source of sediment. Through simulated rainfall tests, the morphological characteristics of rill were quantified by stereophotogrammetry technology, and the relationship between rill development and sediment yield was studied. The results show that there was a positive correlation between sediment yield and slope and rainfall intensities. With the increase in rainfall duration, sediment yield first increased sharply and then decreased gradually after reaching the peak value, until it reached dynamic stability. With the increase in rainfall intensity and slope, the length, width, and number of rills increased significantly, with a maximum length of 2.58 m and a maximum width and depth of 9.7 and 2.2 cm. The rill density (RD) increased from 16.67% to 62.65%; rill fragmentation degree (RFD) increased from 16.67% to 100.00%; rill complexity (RC) increased from 10.62% to 30.84%, and rill width-depth ratio (RWDR) decreased from 15.82% to 56.28% with the increase in slope from 6 degrees to 15 degrees and rainfall intensity from 2.0 to 3.0 mm/min. There was a good nonlinear relationship between sediment yield and RC and RWDR (R-2 = 0.89, NSE = 0.85, n = 10). This study could provide help for the quantification research of rill erosion mechanisms and provide reference for the measurement and scale transformations of soil erosion at different scales.

Automated summary

This study quantified the morphological characteristics of rill erosion using stereophotogrammetry technology through simulated rainfall tests, and investigated the relationship between rill development and sediment yield. The results showed that there was a significant correlation between sediment yield and slope and rainfall intensities, with an increase in rainfall intensity and slope leading to an increase in rill length, width, and number. This study provides valuable insights for understanding the mechanisms of rill erosion and can be used as a reference for soil erosion measurement and scale transformations at different scales.