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Paper Information

Journal:   MODARES CIVIL ENGINEERING JOURNAL   JUNE 2017 , Volume 17 , Number 2 ; Page(s) 215 To 224.
 
Paper: 

EFFECTS OF VARIANT RAINFALL INTENSITY EVENTS ON RUNOFF AND INTERRILL EROSION

 
 
Author(s):  ALAVINIA M.*, NASIRI SALEH F., ASADI H.
 
* FACULTY OF CIVIL AND ENVIRONMENTAL ENG., TARBIAT MODARRES UNIVERSITY
 
Abstract: 

Soil erosion, as a complicated natural phenomenon, is a global challenge threatening soil and water resources. Therefore, accurate understanding of soil erosion, sediment transport processes and their interactions is necessary for prediction of soil erosion. To distinguish between the dominant processes involved in soil loss, soil erosion has been classified into rill and interrill erosion. Rainfall-induced detachment and transport of sediment have a fundamental contribution to interrill and sheet erosion. Instead of observation of natural rain showers, simulation of rainfall is widely used for better understanding of processes involved in soil erosion and their interactions. Rainfall intensity is variable during natural rain showers. Peak rainfall intensity in an event can exceed the mean event intensity by an order of magnitude. Variations of rainfall intensity during arainfall event is called ‘event profile’. However, the available information is inadequate to understand its effects on runoff and soil loss processes. Thus, this study is aimed to quantify the effect of event profile on runoff and soil loss in rainfall-induced erosion. The experiments are defined based on the use of simulated rainfall on disturbed soils in a small laboratory detachment tray. The study is conducted in the rainfall simulation laboratory, Department of Hydraulic, Faculty of Civil and Environmental Engineering, Tarbiat ModaresUniversity, Iran. Since kinetic energy controls runoff and soil loss processes, the effects on the soil surface of rainfall events with the same average intensity may be different. Hence to study only the effects of event profile, four events with different temporal profiles of rainfall intensity, each with the same kinetic energy, were chosen; (a) constant intensity, (b) increasing intensity, (c) decreasing intensity and (d) increasing - decreasing intensity. The soil samples used in the experiments are from sandy soil (soil A) and sandy loam soil (soil B). Disturbed soil samples are collected, air dried, crushed to pass a 4.75-mm sieve, and thoroughly mixed. For each experiment, soil is packed into a drainable detachment tray to a specific bulk density. The test area of this tray is 15-cm width by 30-cm length and 15-cm depth. Eliminating the effects of soil moisture on results, soil is saturated from the bottom using drainage outlet tube connected to a water reservoir 24-hr before each experiment. The tray is setup at a slope of 0.5% and exposed to simulated rainfall events. Each treatment is tested in three replicates. For each simulation, runoff and sediment are sampled at regular intervals. Results show that while the peak runoff is affected by event profile for the two soil types, there is no significant difference in total runoff among rainfall events examined for both soil types. However, the soil type significantly affects the soil loss. In addition, it seems that the models which estimate interrill soil erosion directly from the rainfall intensity are expected to perform poorly in predicting soil erosion from varying intensity rainfall events. It may imply that various and complicated mechanisms might be activated in runoff and erosion under natural rainfall conditions. The results may indicate that negligence of the event profile may lead to inaccurate understanding of mechanisms involved in runoff and soil erosion.

 
Keyword(s): EVENT PROFILE, RUNOFF, SEDIMENT, RAINFALL SIMULATION, INTERRILL EROSION
 
 
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APA: Copy

ALAVINIA, M., & NASIRI SALEH, F., & ASADI, H. (2017). EFFECTS OF VARIANT RAINFALL INTENSITY EVENTS ON RUNOFF AND INTERRILL EROSION. MODARES CIVIL ENGINEERING JOURNAL, 17(2 ), 215-224. https://www.sid.ir/en/journal/ViewPaper.aspx?id=570702



Vancouver: Copy

ALAVINIA M., NASIRI SALEH F., ASADI H.. EFFECTS OF VARIANT RAINFALL INTENSITY EVENTS ON RUNOFF AND INTERRILL EROSION. MODARES CIVIL ENGINEERING JOURNAL. 2017 [cited 2021May16];17(2 ):215-224. Available from: https://www.sid.ir/en/journal/ViewPaper.aspx?id=570702



IEEE: Copy

ALAVINIA, M., NASIRI SALEH, F., ASADI, H., 2017. EFFECTS OF VARIANT RAINFALL INTENSITY EVENTS ON RUNOFF AND INTERRILL EROSION. MODARES CIVIL ENGINEERING JOURNAL, [online] 17(2 ), pp.215-224. Available: https://www.sid.ir/en/journal/ViewPaper.aspx?id=570702.



 
 
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