Soil erosion risk assessment of the Lakhmess watershed (northwestern Tunisia) via the SEAGIS model: Inferred prioritization of risky sub-watersheds  

作　　者：Afef Marghmi Lilia Ben Cheikha Amina Mabrouk El Asmi Moncef Gueddari 

机构地区：[1]Laboratory of Sedimentary Basins and Petroleum Geology,Faculty of Sciences of Tunis,University of Tunis El Manar,Tunis,2092,Republic of Tunisia [2]National Centre for Nuclear Sciences and Technologies,Sidi Thabet,2020,Republic of Tunisia

出　　处：《International Journal of Sediment Research》2024年第6期868-884,共17页国际泥沙研究(英文版)

摘　　要：Water erosion in Tunisian semi-arid regions causes harmful effects by silting reservoirs and reducing agricultural lands and soil fertility.Several factors are involved in the erosion process:rain erosivity,soil fragility,and degraded land cover on steep slopes associated with the intensification of inappropriate human practices.Thus,identifying erosion vulnerable sub-watersheds based on the assessed soil loss rate is very important to apply suitable conservation measures.The current research aimed to prioritize risky areas in the Lakhmess watershed,north-west Tunisia via the Soil Erosion Assessment using Geographical Information System(SEAGIS)model.To prioritize sub-watersheds vulnerable to soil erosion and sediment yield,the Lakhmess watershed,covering an area of 162 km^(2),was divided into 16 sub-watersheds(L1-L16),according to the hydrographic network.Then,the mean annual soil erosion rate and the mean annual sediment yield in the watershed were estimated by integrating the Revised Universal Soil Loss Equation(RUSLE)and the Sediment Delivery Ratio(SDR)in the SEAGIS model and their spatial distribution was determined.The obtained results indicate that the estimated average annual soil erosion rate is 4.2 t/ha/y and the annual sediment yield is 2.6 t/ha/y.Maner's SDR model was selected as the best model for esti-mating SY,with standard error,standard deviation,and coefficient of variation values of o.75%,0.01,and 0.45%,respectively.The prioritization of the Lakhmess sub-watersheds based on the estimated soil loss rate reveals that among the 16 sub-watersheds,three sub-watersheds(L10,L12,and L15)were identified as being in a very high priority soil erosion class.The high soil erosion rate and sediment yield in these sub-watersheds is explained by the steep slope and a high rainfall erosivity factor.Six sub-watersheds(L2,L4,L5,L6,L7,and L16)were found to belong to a very low priority soil erosion class,as they are characterized by a very gentle slope,which appears to be an extremely determining factor.These findi

关 键 词：Water erosion Northwestern Tunisia Soil Erosion Assessment Geographical Information System(SEAGIS)model Revise Universal Soil Loss Equation model(RUSLE) Lakhmess watershed Soil erosion prioritization Multiple soil classes 

分 类 号：S15[农业科学—土壤学]