RUNOFF CURVE NUMBER METHOD IN SICILY: CN DETERMINATION AND ANALYSIS OF THE INITIAL ABSTRACTION RATIO

The Curve Number method is widely used in hydrology because it’s simply based on a single parameter, CN, that represents the basin absorption. In this paper CN is evaluated at basin scale from rainfall-runoff multi-daily events (Mockus, 1964), in the observation period 1940-1997 (record length mean equal to 20 years), for 61 Sicilian basin with three different methods: NEH4 method, Asymptotic fitting method (Hawkins, 1990, Hawkins et al., 2002, Hawkins et al., 2009), Least squares method (Woodward et al., 2006, Hawkins et al., 2009). A first analysis of Sicilian watershed behavior indicates a major occurrence of standard CN response (42 basins), rather than complacent response (11 basins) a…

Caratterizzazione idrologica dei bacini siciliani col metodo del Curve Number

Analisi preliminare per la caratterizzazione idrologica del bacino dell'Alcantara secondo il modello CN-NRCS

Brevi considerazioni su piogge intense e potenzialità di produzione del deflusso superficiale in Sicilia

Vengono presentati i metodi aggiornati per la stima delle precipitazioni intense massime annue di fissato tempo di ritorno in Sicilia. Dall‟osservazione della distribuzione spaziale dei parametri assunti nei modelli di stima emergono aree a maggior rischio riguardo l‟intensità di pioggia, qui commentate. Il richiamo a recenti studi che riguardano la produzione del deflusso superficiale a scala media annua o a scala di evento, consente di avanzare alcune considerazioni di tipo spaziale, con particolare attenzione all‟area del messinese, su questa importante propensione idrologica notoriamente fonte di dissesto idrogeologico e di pericolo alluvionale. The updated methods for the estimation of…

STIMA DELLA RADIAZIONE SOLARE GIORNALIERA IN SICILIA MEDIANTE I DATI DI TEMPERATURA MASSIMA E MINIMA

Curve Number: Empirical Evaluation and Comparison with Curve Number Handbook Tables in Sicily

The curve number (CN) method is widely used for estimating direct runoff depth from rainstorms. The procedure is on the basis of the parameter CN, a lumped expression of basin absorption and runoff potential, and a second parameter, initial abstraction (IA), which represents the interception, infiltration, and surface depression during the early part of a storm. The evaluation of CN in Sicily at a basin scale from rainfall-runoff multiday events is done using rainfall-runoff observations during the period 1940–1997 (mean record length of 20 years) in 61 Sicilian watersheds using three different methods: (1) the national engineering handbook, section 4 hydrology (NEH4) method (NEH4M) (the me…

Empirical determination of the average annual runoff coefficient in the Mediterranean area

Runoff estimation in ungauged basin is a challenge for the hydrological engineers and planners. For an y hydrological study on an ungauged basin, a methodology has to be appropriately selected for the determination of runoff at its outlet. Several meth ods have been used to estimate the basin runoff production. In this study the empirical Kennessey m ethod to determine average annual runoff coefficien t, RC, is tested on 61 Sicilian basins characterized b y different climate conditions, surface permeabilit y, mean slope and vegetation cover. A comparison between observed and calculated RC showed that a calibration of the Kennessey model could be necessary. The slight and not satisfying impr…

Empirical Investigation of Curve Number Method Parameters in the Mediterranean Area

AbstractThe curve number (CN) method is widely used as a technique for estimating surface runoff depth from rainstorms. This simply lumped method is based on the main parameter CN, which represents the lumped expression of basin absorption, and on a parameter that represents interception, infiltration during the early part of a storm, and surface depression storage, called initial abstraction. In this paper, CN is evaluated at the basin scale from rainfall-runoff multiday events, in the observation period 1940–1997 (recorded length mean equal to 20 years) for 61 Sicilian basins with three different methods: NEH4 method, asymptotic fitting method, and a least-squares method. A first analysis…

River Conservation and Phytodepuration in a Mid-Mediterranean Streambed: A Sicilian Case Study

AbstractFor landslide mitigation purposes, a system of two screen dams was created along the main channel of the Capreria River in Sicily. The de facto constructed wetlands occasioned behind the flow-path barriers produced, for several years, an appreciable reduction of organic load of the upstream municipal wastewaters from the nearby town of Riesi, Italy. This coincidence inspires the prospect of promoting a multifunctional role for these slope-stabilization works, thereby allowing them to be viewed from an intriguing and innovative planning perspective.

Estimation of Daily Solar Radiation from Measured Air Temperature Extremes in the Mid-Mediterranean Area

AbstractDaily solar radiation Rs at ground level is a necessary input variable required for the evaluation of evapotranspiration and crop growth, development, and yield-simulation models. Nevertheless, it is measured in few weather stations and at many locations it is not observed; also, available Rs temporal series are generally no longer than a few years. A valid surrogate of Rs measurement is the diurnal air-temperature range (ΔT); indeed, ΔT is inversely proportional to cloudiness and therefore could be a good indicator of atmospheric transmittance. As opposed to Rs, daily maximum and minimum air temperatures are measured at many locations and their observations in developed countries b…

CONFRONTO TRA DATI DI TEMPERATURA RILEVATI IN AREE URBANE E IN AREE AGRICOLE LIMITROFE

Il fenomeno noto come “isola di calore urbana” (Urban Heat Island, UHI), che riguarda prevalentemente i paesi più industrializzati, consiste nell’aumento della temperatura dell’aria nei centri abitati per effetto dell’urbanizzazione. La verifica di tale fenomeno è stata eseguita in Sicilia instaurando un confronto tra le temperature massime, minime e le escursioni termiche di coppie di stazioni di misura, poste rispettivamente all’interno e all’esterno di alcuni centri urbani minori nel periodo 2002-2005. L’analisi è stata sviluppata a scala annuale e semestrale (separando la stagione tipicamente secca, da Aprile a Settembre, da quella umida), in modo da rilevare in quali periodi dell’anno …

DISCUSSION “Curve Number Derivation for Watersheds Draining Two Headwater Streams in Lower Coastal Plain South Carolina, USA” by Thomas H. Epps, Daniel R. Hitchcock, Anand D. Jayakaran, Drake R. Loflin, Thomas M. Williams, and Devendra M. Amatya

Epps et al. (2013) derived Curve Number (CN) values for two forested headwater watersheds in the Lower Coastal Plain of South Carolina during the 2008-2011 period from rainfall-runoff data, resulting in 23 events for the Upper Debidue Creek (UDC) watershed and in 20 events for Watershed 80 (WS80). D’Asaro and Grillone analyzed the P, CN data of the UDC watershed finding an evident “complacent” behavior, characterized by a declining CN with increasing P but without approaching a stable value at large storms. In this case, the traditional runoff CN equation does not fit well with the rainfall-runoff data that indicate a partial source area watershed behavior and are more aptly modeled by the …

A “Case Study” for the Estimation of Daily Solar Radiation from Measured Air Temperature Extremes in the Mid-Mediterranean Area

Stima della radiazione solare giornaliera in sicilia mediante i dati di temperatura massima e minima

By using thermometric data series from 36 sicilian stations , the authors use different relationship for indirect determination of daily solar radiation. The best performance was given by Hargreaves-Samani formula which is then parameterized by the authors for the investigated region.

Curve Numbers Seasonal Variation in Mid-Mediterranean Area

AbstractThe curve number (CN) method is a popular technique for estimating a rainstorm event’s direct runoff (Q from its storm depth P). It relies on the parameter CN, a lumped expression of a wate...

Analisi regionale delle piogge intense in Sicilia

Standard Asymptotic Response and Expected Runoff from Curve Number Theory

The Standard Asymptotic response is a common finding with rainfall-runoff analysis with the Curve Number method. Widely-observed in data analyses, it is the secondary relationship between the data-defined CN and the causative rainfall P, for which the empirical fitting equation CN(P) = CN∞+ (100-CN∞)exp(-kP) has been found to fit well. This is an unexpected variation in the handbook methodology. It is investigated here on a “theoretical” basis by using the handbook tabled values of CN for the three AMC classes, I, II, and III; the storm-to-storm S (=1000/CN-10); and the observed 12-50-88 percent conditional probabilities for the ARC classes. With this, and treating S as a variable across th…

Parametrizzazione del metodo del Curve Number per i bacini siciliani

Simplified Probabilistic-Topologic Model for Reproducing Hillslope Rill Network Surface Runoff

AbstractThis work presents a simplified probabilistic-topologic model for reproducing rill network surface runoff on a square-plane hillslope. The model requires only two parameters: the first is related to the production capacity of overland flow of the hillslope, at the initial conditions of the process, and the second depends on the sinuosity of the rill network. From a hydrological point of view, the following parameters account for the effects that essentially delineate the hydrologic response of a natural hillslope: rainfall intensity, hillslope roughness, and slope. Obviously, the reliability of the model is pending experimental validation that has only just begun. However, a prelimi…

Empirical methods to determine average annual runoff coefficient in Sicilian basins

Applicazione di tecniche di regionalizzazione alle portate al colmo di piena siciliane

Probability Distribution of Peak Discharge at the Hillslope Scale Generated by Hortonian Runoff

In this work, the probability distribution of peak discharge at the hillslope bottom is determined hypothesizing a prevalent Hortonian mechanism of runoff production for a given rainfall duration. As is well known, the probability distribution of peak discharge depends on the probability of both the rainfall event as well as that of the antecedent soil moisture conditions. In particular, the probability of the rainfall event is calculated according to the familiar rainfall duration-intensity-frequency approach, whereas the ecohydrological method from the literature is used here to define the probability of the antecedent soil moisture conditions. The latter depends on a set of parameters de…

REGIONAL FREQUENCY ANALYSIS FOR EXTREME RAINFALL IN SICILY

POSSIBILI MODIFICAZIONI DELLE COMPONENTI DEL BILANCIO IDROLOGICO INDOTTE DALLE VARIAZIONI CLIMATICHE

Comparison between Curve Number empirical values and Curve Number obtained by handbook tables at basin scale in Sicily, Italy

Proposal of a Genome Editing System for Genetic Resistance to Tomato Spotted Wilt Virus

Viruses provoke considerable economical losses in agriculture. New molecular approaches to develop genetic resistance based on translational genomics and precision genetic modifications are highly expected. The type II Clustered, Regularly Interspaced Palindromic Repeats (CRISPR) system including Cas9 nuclease represent a promising and very powerful tool to specifically modulate the expression and activity of genes involved in biotic stress responses. In this study, we describe an approach to develop a platform system based on CRISPR system for genome editing technology in tomato. Tomato is an excellent plant for this approach considering the high-quality genome sequence, the rapid life cyc…