Search results for "MAZ"
showing 10 items of 3205 documents
Effect of plot size on measured soil loss for two Italian experimental sites
2011
The objective of this investigation was to determine empirically the plot width and length effects on runoff volume, Ve, soil loss, Ae, and sediment concentration, Ce, by using data collected, at the temporal scale of the erosive event, on bare plots differing in width (2 to 8 m) and length (11 to 22 m) for two Italian stations (Masse, Umbria; Sparacia, Sicily). Mean results differed by a maximum factor of 1.6 for Ve, 1.8 for Ae and 1.2 for Ce when plots differing in width were compared and by a maximum factor of 1.4 for Ve, 1.2 for Ae and 1.3 for Ce when comparison between plot lengths was conducted. Differences between two plot widths or two plot lengths were not statistically significant…
Analysis of soil loss data from plots of differing length for the Sparacia experimental area, Sicily, Italy
2010
Widely used models of the soil erosion process, such as the empirical universal soil loss equation (USLE) and revised USLE (RUSLE), suggest that soil loss, i.e. the mass of soil lost by water erosion per unit surface area, increases with slope length, λ, although contrasting experimental results may be found in the literature. Experiments were carried out at the Sparacia site, Sicily, to establish the influence of plot length on soil loss. This was tested using data characterised by a high number of replicated, bare plots of different lengths (0.25, 0.4, 1, 2, 5, 11, 22, 33 and 44 m), simultaneously operating in the 1999–2008 period. Event soil losses did not vary significantly with λ or ev…
Establishing a soil loss threshold for limiting rilling
2015
In this paper a frequency analysis of event soil loss measurements collected in the period 1999–2012 at the microplots and plots of the Sparacia Experimental Area in Sicily, southern Italy, was developed. The analysis was carried out using the annual maximum soil loss measurements normalized by the mean soil loss measured at a given temporal and spatial scale. The empirical frequency distribution of the normalized variable was well fitted by two Gumbel’s theoretical probability distributions discriminated by a value of the normalized variable equal to 2. This last value discriminates between the relatively low and frequent values of the normalized variable and the high and rare ones. The an…
Response to ‘comment on “predicting event soil loss from bare plots at two Italian sites”’
2014
In this paper, a response to the comment by Dr. Kinnell on “Predicting event soil loss from bare plots at two Italian sites”’ (Bagarello et al., Catena 109, 96–102, 2013) is provided.
Testing infiltration run effects on the estimated water transmission properties of a sandy-loam soil
2016
Abstract Testing factors influencing determination of soil water transmission properties by an infiltrometer method helps better interpretation of the collected data and allows the development of appropriate sampling strategies for the intended use of the data. These factors include the soil water content at the start of the experiment, the height from which water is poured onto the soil surface, and the duration of the infiltration run. A sandy-loam soil was sampled with the BEST (Beerkan Estimation of Soil Transfer parameters) procedure of soil hydraulic characterization and two heights of pouring of water (0.03 and 1.5 m) under three different initial soil water content, θ i (0.12 ≤ θ i …
Testing the BEST procedure to estimate the soil water retention curve
2012
The BEST (Beerkan Estimation of Soil Transfer parameters) procedure is attractive for simple soil hydraulic characterization but there is the need to test the reliability of the predictions. In this investigation, the BEST procedure to predict water retention of 199 Sicilian soils was evaluated. The BEST water retention model performed well (relative error, Er≤0.05) for approximately 80% of the soil samples. Low errors were obtained in soils with a high clay, cl, content (≥44%), whereas both high and low Er values were obtained in soils with a lower cl content. The BEST particle size distribution (PSD) model was accurate for 50% of the samples and the fitting accuracy increased with cl, wit…
Quick and Slow Components of the Hydrologic Response at the Hillslope Scale
2016
It is widely recognized that the Hortonian mechanism of runoff generation occurs in arid and semi-arid regions, generally characterized by high rainfall intensity on soils exhibiting low infiltrabilities. Differently, in steeply sloping forested watersheds in humid climates, by infiltrating through a highly permeable upper soil horizon, water moves beneath the soil surface determining a slow response. However, in most real cases, for example when in arid regions mountain forested areas take place, both (quick and slow) runoff generation processes coexist and together contribute to the hydrologic hillslope response. In this paper, based on analytical solutions of the hydrologic response, ins…
Identifying a dominant discharge for natural rivers in southern Italy
2012
Abstract Natural rivers are subjected to continuous adjustments in response to any change in the environment. These environmental changes may occur naturally, as in the case of climatic variation or changes in vegetative cover, or may be related to human activities including channelization, damming, bank protection, and bridge construction. Identifying the value of that discharge (‘dominant’ or ‘effective’ discharge, QD) considered responsible for the main changes operated by a river has been a subject of great challenge to scientists and engineers during the last decades. In fact, this threshold value is largely adopted for stream-management decisions, for predicting the stable slope upstr…
Soil hydraulic properties determined by infiltration experiments and different heights of water pouring
2014
Abstract Establishing the dependence of the soil hydraulic characterization carried out by an infiltration experiment on the procedure used to apply water on the confined soil surface may help to better interpret the collected data and also to develop more accurate strategies for soil hydraulic characterization. Soil was sampled at four Sicilian sites with both the Simplified Falling Head (SFH) technique and the Beerkan Estimation of Soil Transfer parameters (BEST) procedure and two heights of water application (0.03 and 1.5 m). The most appropriate BEST algorithm to analyze the data was determined and the effect of the height of water pouring on the measured soil hydraulic properties was e…
New stage-discharge relationships for radial gates
2013
Calibration of gates under free and submerged flow regimes is a classical hydraulic problem. In this paper dimensional analysis was applied to investigate both free and submerged flow conditions through a radial gate. The original Ferro’s method for submerged flow regime was modified by introducing the maximum allowable tail water depth permitting free flow. Based on Buckingham theorem and applying the Incomplete Self Similarity (ISS) concept different forms of the dimensional equations were proposed. According to the current available experimental data the most accurate dimensionless formula was proposed. The proposed dimensional equation not only is more accurate than the original Ferro’s…