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Temporal and spatial variations of runoff and rainwash erosion on an agricultural field

 

作者: L. Mathier,   A. G. Roy,  

 

期刊: Hydrological Processes  (WILEY Available online 1993)
卷期: Volume 7, issue 1  

页码: 1-18

 

ISSN:0885-6087

 

年代: 1993

 

DOI:10.1002/hyp.3360070103

 

出版商: John Wiley&Sons, Ltd

 

关键词: Runoff;Erosion;Sediment transport;Measurement;Parameter variation

 

数据来源: WILEY

 

摘要:

AbstractThis paper investigates the spatial and temporal variations of runoff, erosion and rate of sediment transport on an agricultural field submitted to natural rainfalls. The site, located in the Eastern Townships (Québec, Canada), is a corn field (10000 m2) where sheetwash erosion is active. Water (Q) and sediment (Qs) discharges were measured from June to October at eight locations on the field and for ten rainfall events. Analysis of the data was carried out on an aggregate data set and on the distributed measurements in time and space. The results showed that changes in vegetation, soil compaction and crusting are critical in determining temporal variations of runoff and erosion. Until August, the increase in soil compaction reduced infiltration capacity and depression storage and generated greater runoff for a given rainfall intensity (I). Sediment transport decreased as particle detachment is less likely to occur when vegetation breaks the drop impact and the soil surface is sealed. Later in the season, we observed an increase in sediment concentration associated with the presence of burrowing insects and harvest activity, providing loose sediments to the broken down surface. Intercepts and slopes of the relationship betweenQandQsalso vary during the period of measurement. High sediment availability over the soil surface in June and October gives high intercept values. The slope of the relationship is more stable but difficult to estimate for extreme events (high values ofIor lowQvalues) where the number of sampled points are small. During a rainfall, the response of the field is dominated by the topography and drainage area. The largest amount of runoff and erosion occurred on straight and steep slopes with small drainage areas, and on converging gentle slopes with large drainage areas. Although aggregate runoff and erosion values are decreasing with drainage area, parameters of theQs‐Qrelationship for different locations on the field are not statistically different. These results bear important consequences for models of sheetwash erosion on agricultural fiel

 

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