Application of 3D Photo-reconstruction techniques in Geomorphology: Examples through different landforms and scales

Recent developments made in tri-dimensional photo-reconstruction techniques (3D-PR), such as the use of Structure from Motion (SfM) and MultiView Stereo (MVS) techniques together, have allowed obtaining high resolution 3D point clouds. In order to achieve final point clouds with these techniques, only oblique images from consumer un-calibrated and non-metric cameras are needed. Here, these techniques are used in order to measure, monitor and quantify geomorphological features and processes. Three different applications through a range of scales and landforms are presented here. Firstly, five small gully headcuts located in a small catchment in SW Spain were monitored with the aim of estimat…

Discussion of "extraction of the flow rate equation under free and submerged flow conditions in pivot weirs with different side contractions" by N. Sheikh Rezazadeh Nikou, M. J. Monem, and K. Safavi

This paper is the discusison of the paper "Extraction of the flow rate equation under free and submerged flow conditions in pivot weirs with different side contractions" by N. Sheikh Rezazadeh Nikou, M. J. Monem, and K. Safavi.

A new strategy to assure compliance with soil loss tolerance at a regional scale

The relevant erosive effects of extraordinary rainfall events due to climate change require establishing soil conservation strategies to prevent damages due to hydrogeological instability. The “tolerable” soil loss, i.e., the maximum soil loss compatible with sustainable soil use, represents a quantitative target to establish the effectiveness of actions to control soil erosion. In this paper, a new approach to defining the condition corresponding to a tolerable soil loss is proposed. At first, using the statistical analysis of the measured annual values of the rainfall erosivity factor, the cover and management factor CT, for which the maximum tolerable soil loss is equal to the annual soi…

PLOT LENGTH EFFECTS ON RUNOFF AND SOIL EROSION AT THE SPARACIA EXPERIMENTAL SITE

Explaining scale effects for runoff and erosion improves our understanding of erosion processes. In this investigation, plot length effects on event runoff per unit area, Qe, sediment concentration, Ce, and soil loss per unit area, SLe, were checked at the Sparacia (Italy) site. The most common result, occurring for the 57-62% of the events depending on the considered variable, was the lack of any scale effect. When scale effects were detected, they indicated that longer plots yielded smaller Qe and SLe values and higher Ce values. Rainfall characteristics did not explain the occur-rence of significant scale effects nor they were able to describe changes in the scaling exponent for Ce and S…

Checking generalization of the USLE-MM in central and South Italy

The USLE-MM estimates event normalized plot soil loss, Ae,N, by an erosivity term given by the runoff coefficient, QR, times the single-storm erosion index, EI30, raised to an exponent b1 > 1. In this investigation, carried out at the three experi-mental sites of Bagnara, Masse and Sparacia, in Italy, the soundness of the USLE-MM scheme with a single exponent for the three sites was tested. The model was parameterized both locally and considering all sites simultaneously. The performances of the fitted models were established by considering all erosive events and also by distinguishing between events of different severity. The b1 exponent varied widely among the three sites (1.05 - 1.44) bu…

Caratterizzazione morfologica e idraulica dei rill rilevati nell'area sperimentale di Masse

Nella memoria sono riportati i risultati di un’analisi finalizzata alla validazione in ambiente Umbro di modelli per la quantificazione e la caratterizzazione morfologico-idraulica delle formazioni rill. A tale scopo sono state utilizzate le misure effettuate presso la stazione sperimentale per il monitoraggio dei processi erosivi a scala di parcella in località Masse (Umbria). In seguito a due eventi erosivi (11-01-2010 e 16-05-2011) che hanno prodotto la formazione di rill, è stato effettuato il rilievo della morfologia (lunghezza e sezione) e del profilo degli stessi. Il database di Masse è stato utilizzato, in primo luogo, per la validazione della relazione di potenza che permette la st…

IMPIEGO DEL CONTENUTO IDRICO DEL SUOLO E DEL DEFLUSSO SUPERFICIALE PER LA STIMA DELLA PERDITA DI SUOLO PARCELLARE A SCALA DI EVENTO

Nel presente lavoro viene valutata la potenzialità di accoppiare la USLE con il contenuto d’acqua del suolo pre-evento o il deflusso stimato, per migliorare l’accuratezza della stima della perdita di suolo a scala di singolo evento erosivo. A tale scopo sono stati utilizzati due approcci per i quali la perdita di suolo e il fattore di erosività sono legati da una legge di potenza. Il primo è il modello USLE-MM con deflusso stimato da un modello afflussi deflussi, SCRRM, che importa dati di contenuto d’acqua. Il secondo approccio è quello del modello SM4E che utilizza i dati di contenuto d’acqua pre-evento per correggere il fattore di erosività della pioggia. I due modelli sono stati testati…

Soil loss tolerance in the context of the European Green Deal

Soil erosion by water, and the consequent loss of a non-renewable resource, is a relevant environmental issue which has economic, ecologic, and social repercussions. In the context of the European Green Deal, the increasing awareness of soil Ecosystem Services is leading to give the due relevance to this problem. Notwithstanding the recent soil conservation strategies adopted by the Common Agricultural Policy had positive effects, the concern regarding this topic is drastically increasing for the normalization of extraordinary rainfall events due to climate change. Recent events occurred in Europe demonstrated that landscape protection is often inadequate and interventions to prevent damage…

Testing a spatially distributed sediment delivery model (SEDD) in a forested basin by cesium-137 technique

The aim of the paper is to validate the sediment delivery distributed (SEDD) model for estimating hillslope sediment yield estimates using net soil erosion values obtained by the cesium-137 technique. The cesium-137 technique provides spatially-distributed measurements useful to verify the predictive capability of a distributed sediment yield model. The application of the cesium-137 technique requires a calibration procedure to convert measurements of 137Cs inventories to estimates of net soil erosion rates. Rainfall and sediment yield data from 1978 to 1994 in a small Calabrian basin forested with eucalyptus trees, were initially used to calibrate, at mean annual temporal scale, the SEDD m…

Testing flow resistance equation for rill flow

At first, in this paper a flow resistance equation for rill flow, deduced applying dimensional analysis and self-similarity theory, is presented. The incomplete self-similarity hypothesis is used for establishing the flow velocity distribution whose integration gives the theoretical expression of the Darcy-Weisbach friction factor. Then the deduced theoretical resistance equation, which is calibrated by some measurements of flow velocity, water depth, cross section area, wetted perimeter and bed slope carried out in 106 reaches of some rills modelled on an experimental plot, is tested using the literature data by Abrahams et al. (1996), Strohmeier et al. (2014) and Peng et al. (2015) for ri…

Experimental investigation of flow characteristics in vegetated channels

Testing the SEDD model in Sicilian basins

Abstract The Sediment Delivery Distributed (SEDD) model combines the universal soil loss equation (USLE) or the revised universal soil loss equation (RUSLE) with a sediment delivery ratio to predict basin sediment yield. The model was applied to seven Sicilian basins, ranging in size from 20 to 213 km2 . Each basin has a reservoir located at its outlet. The model was applied to each basin using a raster scheme, and a subroutine of ArcInfo software to identify the hydraulic path linking each hillslope cell to the nearest stream cell, and to calculate both the travel time and the sediment delivery ratio of each cell. A procedure for estimating the β coefficient, which appears in the expressio…