Gully morphological characteristic indicators are important parameters to study gully erosion processes quantitatively

but there are only a few reports on the study of gully morphological characteristics at active stage due to the limitation of DEM resolution. 30 typical gullies were randomly selected in different watershed locations and gully orders. Extraction method of gully morphological characteristic indicators was established based on the 3-D laser scanning technique (LIDAR)

differences of gully morphological characteristic indicators extracted from 0.1 m and 5 m DEMs were analyzed and transform models of gully morphological characteristic indicators between different resolution DEMs were established. The results showed that gully morphological characteristic indicators extracted from 0.1 m-resolution DEM and manual measurement had no significant difference; gully length

width

depth

surface area and volume extracted from 0.1 m resolution DEM was 94.0%

109.1%

107.7%

80.1% and 109.0% of that obtained by manual measurement

indicating that 0.1 m-resolution DEM could be used to extract gully morphological characteristic indicators accurately. Gully length extracted from 0.1 m-resolution DEM had no significant difference with that extracted from 5 m-resolution DEM

while gully width

depth

surface area and volume extracted from 0.1 m-resolution DEM had significant difference with those extracted from 5 m-resolution DEM. Gully width

surface area and volume extracted from 5 m-resolution DEM was 28.6%

25.6% and 19.7% greater than that extracted from 0.1 m-resolution DEM

respectively

while gully depth extracted from 5 m-resolution DEM was 37% smaller than that extracted from 0.1 m-resolution DEM. Therefore

transform models of gully width

surface area and volume were established. Model validation results showed that the correlation coefficients of gully width

surface area and volume transform model were all greater than 0.6 and effectiveness coefficients were all greater than 0.5

indicating that the accuracies of the three transform models were all acceptable. This study provides an important method for the study of gully erosion characteristics in the loess hilly-gully region.