Grid order prediction of ephemeral gully head cut position: Regional scale application, 2021

This study compares methods for predicting where ephemeral gullies form in agricultural landscapes using high-resolution LiDAR data, finding that a grid order (GORD) approach can locate gully head positions more reliably than traditional topographic index models—without the need for local calibration. Testing across eight Iowa watersheds showed that GORD prediction remained stable and acceptably accurate, even as soil and slope varied by region, while other methods required specific setup to maintain accuracy. The grid order approach is especially useful for conservation planning because it allows efficient, automated identification of vulnerable areas using detailed surface elevation models. However, more research is needed on steeper slopes and under different management practices, and the method’s accuracy depends on the quality of elevation data and field conditions.