Efficient detection of ephemeral gully trajectories using topographic index-based approach:Calibration-free for large-scale applications  

作　　者：Hamid Mohebzadeh Asim Biswas Ben DeVries Ramesh Rudra Derek T.Robinson Prasad Daggupati 

机构地区：[1]School of Engineering,University of Guelph,Guelph N1G2W1,Canada [2]School of Environmental Sciences,University of Guelph,Guelph N1G2W1,Canada [3]Department of Geography,Environment and Geomatics,University of Guelph,Guelph N1G2W1,Canada [4]Department of Geography and Environmental Management,University of Waterloo,Waterloo N2L 3G1,Canada

出　　处：《International Journal of Sediment Research》2024年第4期586-600,共15页国际泥沙研究（英文版）

基　　金：supported by the Natural Sciences and Engineering Research Council of Canada(NSERC)and the Ontario Ministry of Agriculture,Food and Rural Affairs(OMAFRA)Agrifood Alliance.

摘　　要：In agricultural landscapes,the use of topographic index(TI)models has been common to predict the presence and extent of ephemeral gullies(EGs).However,these models face two significant challenges:(1)the accurate prediction of EGs relies heavily on a critical threshold(CT)value,which is difficult to determine optimally using existing strategies,and(2)the calibration of TI models limits their applicability on a larger scale.To address these limitations,the current study proposes two methods:(1)the division of the study area into zones based on key factors influencing gully formation,reducing the need for TI model calibration,and(2)a pixel-based binary classification approach coupled with a precision performance metric to identify the calibrated CT value within a watershed.The performance of seven TI models for predicting EG length was evaluated using local validation within zones and transferred validation between zones.Local validation demonstrated that among the TI models,modified stream power index(MSPI),stream power index(SPI),and compound topographic index(CTI),in descending order,yielded the most accurate predictions for EG length.Furthermore,the decrease in accuracy observed in the transferred MSPI model compared to the local MSPI model supported the study's hypothesis that dividing a large-scale area into distinct zones with varying topographic and climatic characteristics enables the determination of a CT value specific to each zone.Soil loss rates due to EGs ranged from 0.36 to 1 kg/m²yr,aligning with findings from similar global studies.These findings offer valuable insight that can be integrated into comprehensive watershed and soil erosion models.

关 键 词：Ephemeral gully erosion Topographic index Critical threshold Soil loss volume Large-scale applications 

分 类 号：S15[农业科学—土壤学]