Search results for "rill erosion"

A Maximizing Hydraulic Radius (MHR) method for defining cross-section limits in rills and ephemeral gullies

2021

Abstract In this paper, a new method for determining the cross-section limits in rills and ephemeral gullies is proposed. This method is based on the estimate of the actual depth ha of each cross-section, which is the particular depth distinguishing the channel from the hillslope areas. The analysis showed that the actual depth corresponds to a particular bank slope sta occurring for the maximum value of the hydraulic radius R. The method was applied using a volumetric approach for calculating the hydraulic radius as the ratio between the volume of the whole investigated channel and its boundary lateral surface. The value of the bank slope st was derived by the DEM of the whole channel late…

Evaluating the Effects of the Rill Longitudinal Profile on Flow Resistance Law

2022

In this paper, for the first time, the effect of the longitudinal profile shape of the rill (uniform, concave, and convex) on flow resistance law was studied. The first part of the paper is based on a theoretical equation to estimate the Darcy–Weisbach friction factor f, deduced from the power velocity distribution and rill measurements performed on a plot. At first, the equation to estimate the Γ parameter of the velocity profile was calibrated using all available measurements. Then an analysis of the hydraulic characteristics at reach scale, for comparable values of discharge, was carried out, comparing the different profile shapes. To assess the influence of the rill profile …

Field investigation on rilling in the experimental Sparacia area, South Italy

2008

In this paper the results of a field investigation on rilling carried out in the experimental Sparacia area are reported. The measurements were made on a plot 6 m wide and 22 m long subjected to natural rainfalls. For ten rainfalls the total soil loss (interrill and rill erosion) was collected in a storage system consisting of two tanks arranged in series at the base of the plot. Rill morphology (rill length and cross-sections) was measured for five rainfall events, while the rill profile was surveyed for three events. First the contribution of each component (rill and interrill erosion) to total soil loss was established. Then the analysis allowed establishment of a power relationship betw…

Finding Possible Weakness in the Runoff Simulation Experiments to Assess Rill Erosion Changes without Non-Intermittent Surveying Capabilities

2020

The Terrestrial Photogrammetry Scanner (TEPHOS) offers the possibility to precisely monitor linear erosion features using the Structure from Motion (SfM) technique. This is a static, multi-camera array and dynamically moves the digital videoframe camera designed to obtain 3-D models of rills before and after the runoff experiments. The main goals were to (1) obtain better insight into the rills

Morphological characteristics of ephemeral gullies in Sicily, south Italy

2011

Ephemeral gullies (EGs) are channels of different sizes refilled by tillage equipment normally used on farms. In this paper, the data-set collected from 1995 to 2007 in a wheat-cultivated area in Raddusa (Sicily, Italy), having a surface of almost 80 ha, were used to analyze the morphological characteristics of EGs. The measurements show an high temporal variability in EG characteristics. The EG measurements and the rill erosion measurements carried out in 15 plots located in the experimental “Sparacia” area (Sicily), demonstrated that a morphological similarity condition exists between rills and ephemeral gullies. The occurrence of step-pool structures in an EG occurring in the observation…

Studio sperimentale sulle resistenze al moto di correnti nei rill

Testing assumptions and procedures to empirically predict bare plot soil loss in a Mediterranean environment

2014

Empirical prediction of soil erosion has both scientific and practical importance. This investigation tested USLE and USLE-based procedures to predict bare plot soil loss at the Sparacia area, in Sicily. Event soil loss per unit area, Ae, did not vary appreciably with plot length, λ, because the decrease in runoff with λ was offset by an increase in sediment concentration. Slope steepness, s, had a positive effective on Ae, and this result was associated with a runoff coefficient that did not vary appreciably with s and a sediment concentration generally increasing with s. Plot steepness did not have a statistically detectable effect on the calculations of the soil erodibility factor of bot…

Quantifying interrill and ephemeral gully erosion in a small Sicilian basin

2012

Plot rill erosion measurements by close-range photogrammetry using natural events at Sparacia experimental area

2018

Recently, many investigations were carried out in order to check the applicability of both close-range and UAV (Unmanned Aerial Vehicle) photogrammetry to measure soil erosion processes. For measuring rill erosion occurring on a 22 m long and 26% sloped plot occurred on 24 October 2016 at the Sparacia experimental area, a terrestrial photographic relief and a low altitude aerial relief were carried out by no-professional quadricopter and camera. The three-dimensional (3D) DTM and the quasi-tridimensional (DEM) models were obtained. An extraction method of the rill network using DEM and convergence index was applied and a subsequent separation of rills into contributing and non-contributing …

MEASURING FIELD RILL ERODIBILITY BY A SIMPLIFIED METHOD

2016

Many process-oriented erosion prediction models reproduce rill erosion as affected by site-specific parameters, as for example, rill erodibility, and thus, their practical application requires the measurement of these parameters or their estimate. The aim of this paper was establishing a method for indirectly measuring field rill erodibility. A simple mathematical approach based on a known soil detachment equation and accounting for the rill erosion dynamic process is applied. Field measurements carried out for seven natural rainfall events occurring at the plots of the Sparacia experimental station, southern Italy, are used for indirectly measuring the rill erodibility of the investigated …