Temporal and Spatial Characteristics and Influencing Factors of Runoff-Gully in Rammed Earthen Sites in Arid Area

Abstract

ABSTRACT Runoff gullies are among the most typical and common disorders in rammed earthen sites. However, only a few studies have effectively elucidated their developmental characteristics, influencing factors, and evolutionary mechanisms. Here, employing 15 sites in three climatic areas and five dynasties as the research objects and based on the investigation and statistics of runoff gullies, standard grading of gully erosions in single sites, classification of the ages of the gullies, and test for the refined disintegration processes of rammed earth using the H-FRA and AHP-EWM-TOPSIS methods, a preliminary study on the temporal and spatial characteristics of the development, as well as influencing factors of gullies, was conducted. The results indicated that the age development of the gullies in the 15 sites proceeded via alternating surface and bottom erosions and that the gullies were mainly at their early and mature stages at this time. The comprehensive degrees of gully erosion exhibited the following temporal and spatial patterns: semi-arid > extreme-arid > arid area and Ming > Han > Qing > Tang > Song Dynasties. Further, the AHP-EWM-TOPSIS model with the disintegration index positively affected the temporal and spatial variations of the comprehensive development degrees of gullies, with up to 93.33% accuracy.