Analisi dell’influenza della risoluzione spaziale di un TIN sulla risposta idrologica a scala di bacino

Modelling of Rainfall Induced Landslides in Puerto Rico

Exploiting historical rainfall and landslide data in a spatial database for the derivation of critical rainfall thresholds

Critical rainfall thresholds for landslides are powerful tools for preventing landslide hazard. The thresholds are commonly estimated empirically starting from rainfall events that triggered landslides in the past. The creation of the appropriate rainfall–landslide database is one of the main efforts in this approach. In fact, an accurate agreement between the landslide and rainfall information, in terms of location and timing, is essential in order to correctly estimate the rainfall–landslide relationships. A further issue is taking into account the average moisture conditions prior the triggering event, which reasonably may be crucial in determining the sufficient amount of precipitation.…

Ecohydrology in Mediterranean areas: a numerical model to describe growing seasons out of phase with precipitations

Geostatistical techniques for runoff mapping: an application to Sicily, Italy

The availability of reliable and long time series of runoff data is fundamental for most of the hydrological analyses and for the assessment and the management of water resources even in condition of global climatic change. However, hydrologic data sets are often characterized by a short duration and also suffer from missing data values, mainly due to malfunctioning of gauging stations for a specific period. In order to overcome this problem and obtain long and continuous runoff time series, different models and methods have been previously developed and proposed. While some models, used to extent the streamflow record, are conceptual, empirical, regressive models based on the rainfall inpu…

The role of hydrology on enhanced weathering for carbon sequestration in soils

Natural climate solutions are attracting considerable research effort with the aim of reducing greenhouse gas emissions or sequestering carbon within the oceans or terrestrial environments. In this context, enhanced weathering can be a powerful means of increasing the natural weathering reaction rates, by adding some highly reactive minerals to the soil. The present study evaluates the effects of hydrologic fluctuations on Forsterite dissolution, a silicate mineral also known as Mg-olivine. This mineral is available in many parts of the world and its reaction rates with CO2 are much higher than those of other minerals. Toward this goal, we developed a mathematical model coupling biogeochemi…

Effects of initialization on response of a fully-distributed hydrologic model

Summary Knowledge of initial conditions is very important to correctly model the basin response at the storm event scale. Of particular interest is the influence of topography and soil type on the principal hydrologic variables and runoff generation mechanisms as a function of antecedent wetness conditions. This study addresses the influence of initial states on the short-term hydrologic response and characterizes the effects of topography and soils on the dissipation of the influence of the initialization conditions. Two case studies are considered: a synthetic two-dimensional planar hillslope with various assumed slope magnitudes and soil types; and a real basin (∼800 km2) with actual lan…

Extreme rainfall changes induced by future climate in Mediterranean area

Extreme rainfall events have large impacts on society and are likely to continue to do so under predicted future climate change. Indeed, extreme precipitations show intensification in many regions of the world and this is of key importance to society as a result of the large impact of flooding. Thus, for planning and management decisions of the hydraulic infrastructures, accurate estimates of precipitation magnitudes at different durations are needed. Moreover, extreme precipitation events represent an increasing threat to society under global warming and are among the most serious challenges. In fact, future climate change is likely to lead to the change of extremes events that will become…

Annual flow duration curves assessment in ephemeral small basins

Flow duration curve (FDC) represents a comprehensive signature of temporal runoff variability often used to synthesize catchment rainfall-runoff responses. A new model, the ModABa (MODel for Annual flow duration curves assessment in ephemeral small BAsins), is here introduced. It can be thought as a wide mosaic whose tesserae are frameworks, models or conceptual schemes separately developed in different studies and harmoniously interconnected with the final aim of reproducing the annual FDC in intermittent small catchments. Two separated seasons within the hydrological year are distinguished: a dry season, characterized by absence of streamflow, and a non-zero season. Streamflow is disaggre…

Exploring single polarization X-band weather radar potentials for local meteorological and hydrological applications

Summary The aim of this study is to evaluate the potential use of a low-cost single polarization X-band weather radar, verified by a disdrometer and a dense rain gauge network, installed as a supporting tool for hydrological applications and for monitoring the urban area of Palermo (Italy). Moreover, this study focuses on studying the temporal variability of the Z–R relation for Mediterranean areas. The radar device is provided with an automatic operational ground-clutter filter developed by the producer. Attention has been paid to the development of blending procedures between radar measurements and other auxiliary instruments and to their suitability for both meteorological and hydrologic…

Utilizzo delle statistiche direzionali per la caratterizzazione delle precipitazioni intense in Sicilia

Le precipitazioni intense costituiscono la fase finale dei processi che interessano i flussi atmosferici e di umidità nonché l'interazione di questi ultimi con l’orografia. La caratterizzazione delle precipitazione intense risulta essenziale al fine di valutare i rischi per la società e per le infrastrutture idrauliche. Stime attendibili di tali eventi sono dunque necessarie per la quantificazione e per la gestione del rischio idrologico. Lo studio qui presentato mira alla valutazione di elementi per la caratterizzazione degli eventi intensi nel territorio siciliano, sulla base dell'analisi statistica e spaziale del dataset di precipitazioni massime annuali registrate dalla rete pluviografi…

Modeling the shrub and juniper encroachment in the western north America grasslands with a Cellular Automata model

EFFETTI DELLE VARIAZIONI CLIMATICHE SULLA VEGETAZIONE IN AMBIENTE MEDITERRANEO

Preface to theHydrological processes in urban environments: Updates on urbanization, naturalization and climate changeSpecial Issue

La qualità nel monitoraggio di variabili meteoclimatiche

A weather monitoring system for the study of precipitation fields, weather, and climate in an urban area

The possibility to study the precipitation dynamics with advanced and specific tools is an important task of the research activity addressing the understanding, the modeling, and the managing of rainfall events. Over the last years, the hydrology laboratory of the Department of Civil, Environmental, Aerospace Engineering, and Materials (DICAM) at the University of Palermo, has installed several instruments for the monitoring and the study of precipitation within the urban area of Palermo (Italy). The main instrument of this system is the X-band weather radar, which allows monitoring the precipitation fields with high resolution in space and time. This instrument is supported by a rain gauge…

Reti per il monitoraggio meteoclimatico

Sviluppo di un sistema di monitoraggio per lo studio delle dinamiche meteorologiche nell'area urbana di Palermo.'

Development of innovative approaches for evaluating drought vulnerability and selecting innovative practices for managing water shortage (in Sicily)

The climate, especially with regard to the precipitation and the evapotranspiration processes, plays a fundamental role in the vegetational patterns formation and modifications. The pilot project here described tries to evaluate in a quantitative way the impact of different climatic regimes (current or future) on vegetation health status and its physiological processes. In particular, an ecohydrological approach has been adopted in order to carry out an analysis of the potential climate changes influence on the vegetation state in a typical Mediterranean environment, such as the Sicilian one.

A physically-based and distributed approach to analyze soil erosion and rainfall triggered landslides at a watershed scale

Ecohydrological modelling of flow duration curve in Mediterranean river basins

Abstract Flow duration curve provides an important synthesis of the relevant hydrological processes occurring at the basin scale, and, although it is typically obtained from field observations, different theoretical approaches finalized to its indirect reconstruction have been developed in recent years. In this study a recent ecohydrological model for the probabilistic characterization of base flows is tested through its application to a study catchment located in southern Italy, where long historical series of daily streamflow are available. The model, coupling soil moisture balance with a simplified scheme of the hydrological response of the basin, provides the daily flow duration curve. …

Influenza della correlazione seriale nell'analisi di trend in serie di variabili climatiche in Sicilia

Strategic Master Plans

The MEDIWAT Project (Sustainable management of environmental issues related to water stress in Mediterranean Islands) aims to provide innovative and sustainable technical, operational and managerial solutions for tackling problems caused by water resources-quality worsening and shortage in the Mediterranean insular context. The project brings together partners from six Mediterranean islands: Sicily, Cyprus, Corsica were considered large islands because of their area and hydrological behavior. Conversely Crete, Malta and Balearic Islands were considered small islands. A detailed analysis of current and future conditions relating to freshwater availability, quality and use has been carried ou…

A Comparison between Heuristic, Statistical and Data-driven Methods in Landslide Susceptibility Assessment: an Application to the Briga and Giampilieri Catchments

Susceptibility assessment concerning the estimation of areas prone to landslide is one of the most useful approach in the analysis of landslide hazard. Over the last years, in an attempt to find the best approach to evaluate landslide susceptibility, many methods have been developed. Among these, the heuristic, the statistical, and the data-driven approaches are very widespread, and they all are based on the concept that the conditions which led to landslide movements in the past will control the probability of movement occurrence in the future. This study presents an assessment of landslide susceptibility in which models of the three different methodologies, such as the heuristic approach,…

Comparative analysis of different techniques for spatial interpolation of rainfall data to create a serially complete monthly time series of precipitation for Sicily, Italy

Abstract The availability of good and reliable rainfall data is fundamental for most hydrological analyses and for the design and management of water resources systems. However, in practice, precipitation records often suffer from missing data values mainly due to malfunctioning of raingauge for specific time periods. This is an important issue in practical hydrology because it affects the continuity of rainfall data and ultimately influences the results of hydrologic studies which use rainfall as input. Many methods to estimate missing rainfall data have been proposed in literature and, among these, most are based on spatial interpolation algorithms. In this paper different spatial interpo…

Ecohydrology in Mediterranean areas: a numerical model to describe growing seasons out of phase with precipitations

The probabilistic description of soil moisture dynamics is a relatively new topic in hydrology. The most common ecohydrological models start from a stochastic differential equation describing the soil water balance, where the unknown quantity, the soil moisture, depends both on spaces and time. Most of the solutions existing in literature are obtained in a probabilistic framework and under steady-state condition; even if this last condition allows the analytical handling of the problem, it has considerably simplified the same problem by subtracting generalities from it. <br><br> The steady-state hypothesis, appears perfectly applicable in arid and semiarid climatic areas like th…

Elaborazione di una mappa di suscettibilità delle aree in frana a scala di bacino

Le frane costituiscono uno tra i più pericolosi e dannosi eventi naturali. Negli ultimi decenni si sono succeduti numerosi eventi catastrofici che hanno provocato, oltre a danni ingenti, anche numerosi morti e dispersi. Per questo motivo cresce sempre di più l’esigenza di fornire ai pianificatori e gestori del territorio strumenti di supporto per la valutazione del pericolo da frana. In questo contesto, negli ultimi anni sono stati sviluppati nuovi approcci per la valutazione della propensione di un’area a produrre scivolamenti, basandosi sulla correlazione tra i fattori innescanti e le occorrenze di scivolamenti. Nel presente lavoro viene presentata una mappa di suscettibilità creata attra…

Modeling vegetation effects on hydrological and mechanical mechanisms of shallow landslides

Effects of vegetation in improving slope stability can be recognized on both hydrological and mechanical mechanisms. With regard to the hydrological effect, vegetation leads to lower porewater pressure and soil moisture due to interception by foliage of rainfall, which reduces the amount of water available for infiltration, or uptake by root system of soil moisture. With regard to the mechanical aspects, root system, due to their tensile strength and frictional or adhesive properties, reinforce the soil and thus increase the resistance of soil. This mechanical effect is at times the most significant and in slope stability analysis is taken into account by means of the apparent root cohesion…

Stochastic assessment of climate impacts on hydrology and geomorphology of semiarid headwater basins using a physically-based model

Hydrologic and geomorphic responses of watersheds to changes in climate are difficult to assess due to projection uncertainties and nonlinearity of the processes that are involved. Yet such assessments are increasingly needed and call for mechanistic approaches within a probabilistic framework. This study employs an integrated hydrology-geomorphology model, the Triangulated Irregular Network-based Real-time Integrated Basin Simulator (tRIBS)-Erosion, to analyze runoff and erosion sensitivity of seven semiarid headwater basins to projected climate conditions. The Advanced Weather Generator is used to produce two climate ensembles representative of the historic and future climate conditions f…

Investigating the changes in extreme rainfall in Sicily

Changes in extreme rainfall are one of the most relevant sign of current climate alterations. Many studies have demonstrated an increase in rainfall intensity and a reduction of frequency in several areas of the world. This could be probably due to an acceleration of the hydrological cycle caused by temperature increase and could have, as consequence, the increase of flooding hazard. In the past, Sicily has been screened for several signals of possible climate change. Annual, seasonal and monthly rainfall data in the entire Sicilian region have been analyzed, showing a global reduction of total annual rainfall, which is mainly due to the winter reduction. Moreover, some annual maximum rainf…

Application of Dora-2D model to a distributed catchment dynamics

Accounting for soil parameter uncertainty in a physically based and distributed approach for rainfall-triggered landslides

In this study we propose a probabilistic approach for coupled distributed hydrological-hillslope stability models that accounts for soil parameters uncertainty at basin scale. The geotechnical and soil retention curve parameters are treated as random variables across the basin and theoretical probability distributions of the Factor of Safety (FS) are estimated. The derived distributions are used to obtain the spatio-temporal dynamics of probability of failure, in terms of parameters uncertainty, conditioned to soil moisture dynamics. The framework has been implemented in the tRIBS-VEGGIE (Triangulated Irregular Network (TIN)-based Real-time Integrated Basin Simulator-VEGetation Generator fo…

Il clima nell'isola? Tende all'aridità, lo dicono le variabili pioggia e temperatura

A physically-based and distributed approach to analyze rainfall-triggered landslides at a watershed scale

Derivation of critical rainfall thresholds for landslide in Sicily

Rainfall is the primary trigger of shallow landslides that can cause fatalities, damage to properties and economic losses in many areas of the world. For this reason, determining the rainfall amount/intensity responsible for landslide occurrence is important, and may contribute to mitigate the related risk and save lives. Efforts have been made in different countries to investigate triggering conditions in order to define landslide-triggering rainfall thresholds. The rainfall thresholds are generally described by a functional relationship of power in terms of cumulated or intensity event rainfall-duration, whose parameters are estimated empirically from the analysis of historical rainfall e…

Gestire l’incertezza parametrica nell’utilizzo di un modello di deflussi giornalieri di tipo shot noise

Investigating the Reliability of Stationary Design Rainfall in a Mediterranean Region under a Changing Climate

Extreme rainfall events have been more frequent in recent decades, potentially as a climate change effect. This has been leading to a higher risk of the failure of existing hydraulic infrastructures, and to a higher awareness regarding the unreliability of design rainfall calculated with reference to historical data recorded in the last century. With this in mind, the present study questions the stationary assumption of the rainfall Depth–Duration–Frequency curves commonly used in Sicily, the biggest island of the Mediterranean Sea. Quantiles derived from the most up-to-date regional method, regarding Sicily, based on observations in the period 1928–2010, have been compared with those extra…

Object-based image analysis technique for gully mapping using topographic data at very high resolution (VHR)

An accurate mapping of gullies is important since they are still major contributors of sediment to streams. Mapping gullies can be difficult because of the presence of dense canopy, which precludes the identification through aerial photogrammetry and other traditional remote sensing methods. Moreover, the wide spatial extent of some gullies makes their identification and characterization through field surveys a very large and expensive proposition. One cheaper and more expeditious way to detect gullies can be achieved in terms of morphological characteristics by the Digital Elevation Models (DEMs). The recent widespread availability of very high resolution (VHR) imagery, such as LIDAR data,…

Monitoraggio di frane attivate da precipitazione a supporto di un Early Warning System: Progetto SESAMO

Using very high resolution (VHR) imagery within a GEOBIA framework for gully mapping: an application to the Calhoun Critical Zone Observatory

AbstractGully erosion is a form of accelerated erosion that may affect soil productivity, restrict land use, and lead to an increase of risk to infrastructure. An accurate mapping of these landforms can be difficult because of the presence of dense canopy and/or the wide spatial extent of some gullies. Even where possible, mapping of gullies through conventional field surveying can be an intensive and expensive activity. The recent widespread availability of very high resolution (VHR) imagery has led to a remarkable growth in the availability of terrain information, thus providing a basis for the development of new methodologies for analyzing Earth's surfaces. This work aims to develop a ge…

Analisi di storm tracking nell’area urbana di Palermo attraverso dati di pioggia ad alta risoluzione

La conoscenza della distribuzione spaziale e temporale delle piogge di breve durata, nonché la loro cinematica, sono alcuni tra i fattori più importanti che stanno alla base dell’approssimazione dei modelli di trasformazione afflussi-deflussi nei bacini urbani. L'incertezza dovuta alla variabilità spaziale della pioggia può influenzare, ad esempio, le performance dei modelli di drenaggio urbano. Un'adeguata conoscenza della variabilità spaziale e temporale delle precipitazioni può essere considerata un passo fondamentale per un'esatta interpretazione dei processi idrologici di base che avvengono nei sistemi di drenaggio urbano durante gli eventi di pioggia intensi. L'analisi di tali informa…

Meteorological monitoring networks

Effects of precipitation seasonality, vegetation cycle, and irrigation on enhanced weathering

Enhanced Weathering (EW) is a promising strategy for carbon sequestration, but several open questions remain regarding the actual rates of dissolution in conditions of natural hydroclimatic variability in comparison to laboratory experiments. In this context, models play a pivotal role, as they allow exploring and predicting EW dynamics under different environmental conditions. Here a comprehensive hydro-biogeochemical model has been applied to four cropland case studies (i.e., Sicily and the Padan plain in Italy and California and Iowa in the USA) characterized by different rainfall seasonality, vegetation (i.e., wheat for Sicily and California and corn for Padan plain and Iowa), and soil …

Climate change effects on the hydrological regime of small non-perennial river basins.

Recent years have been witnessing an increasing interest on global climate change and, although we are only at the first stage of the projected trends, some signals of climate alteration are already visible. Climate change encompasses modifications in the characteristics of several interrelated climate variables, and unavoidably produces relevant effects on almost all the natural processes related to the hydrological cycle. This study focuses on potential impacts of climate variations on the streamflow regime of small river basins in Mediterranean, seasonally dry, regions. The paper provides a quantitative evaluation of potential modifications in the flow duration curves (FDCs) and in the p…

Large-Eddy Simulation e tecnica LS-PIV: lo studio della turbolenza superficiale

Gli avanzamenti tecnologici degli ultimi decenni hanno fatto registrare la rapida diffusione di tecnologie innovative con cui condurre un monitoraggio ambientale più efficiente ed efficace. Nel campo del monitoraggio fluviale sono sempre più utilizzate le tecniche basate sull’elaborazione di immagini, fornendo una valida alternativa alle metodologie tradizionalmente adottate. Le tecniche ottiche restituiscono infatti misure non intrusive, assicurando migliori condizioni di sicurezza per gli operatori. I metodi ottici più utilizzati sono la Large-Scale Particle Image Velocimetry (LS-PIV) [1] e la Large-Scale Particle Tracking Velocimetry (LS-PTV) [2]. Le tecniche LS-PIV e LS-PTV si basano su…

MODELLING RUNOFF WITH A CONCEPTUAL MODEL BASED ON INTEGRATION OF TOPOGRAPHIC INDEX IN A PROBABILITY DISTRIBUTED MODEL

Design storm prediction and hydrologic modeling using a Web-GIS approach on a Free software platform

Abstract The aim of this work has been to implement a set of procedures useful to automatise the evaluation, the design storm prediction and the flood discharge associated with a selected risk level. For this purpose a Geographic Information System has been implemented using Grass 5.0. One of the main topics of such a system is a georeferenced database of the highest intensity rainfalls and their assigned duration recorded in Sicily. This database contains the main characteristics for more than 250 raingauges, as well as the values of intense rainfall events recorded by these raingauges. These data are managed through the combined use of the PostgreSQL and GRASS-GIS 5.0 databases. Some of t…

Utilizzo degli l-moments per l’analisi regionale delle portate di piena in Sicilia. Atti del XXX Convegno di Idraulica e Costruzioni Idrauliche.

Olive Yield and Future Climate Forcings

Abstract The rainfall reduction and the temperature increase forecasted for Mediterranean regions would likely increase the vegetation water stress and decrease productivity in rainfed agriculture. Olive trees, which have traditionally been grown under rainfed conditions, are one of the most characteristic tree crops from the Mediterranean not only for economical importance but also for minimizing erosion and desertification and for improving the carbon balance of these areas. In order to simulate how climatic change could alter soil moisture dynamics, biomass growth and fruit productivity, a water driven crop model is used in this study. The model quantitatively links olive yield to climat…

An Ecohydrological Cellular Automata Model Investigation of Juniper Tree Encroachment in a Western North American Landscape

Woody plant encroachment over the past 140 years has substantially changed grasslands in western North American. We studied encroachment of western juniper (Juniperus occidentalis var. occidentalis) into a previously mixed shrub–grassland site in central Oregon (USA) using a modified version of Cellular Automata Tree–Grass–Shrub Simulator (CATGraSS) ecohydrological model. We developed simple algorithms to simulate three encroachment factors (grazing, fire frequency reduction, and seed dispersal by herbivores) in CATGraSS. Local ecohydrological dynamics represented by the model were first evaluated using satellite-derived leaf area index and measured evapotranspiration data. Reconstruc…

Sviluppo di un Sistema Informativo Territoriale per l’analisi a scala regionale dello stato di qualità dei corpi idrici siciliani

Stima dell'erosione idrica in due bacini siciliani mediante tecniche GIS

EHSMu: a new conceptual model for hourly discharge simulation under ecohydrological framework in urban area

A parsimonious conceptual lumped model is presented here with the aim of simulating hourly discharge in urban areas. The EHSMu (EcoHydrological Streamflow Model for urban areas) is able to reproduce the discharge at the outlet of an urban drainage system and, at the same time, soil moisture dynamics and evapotranspirative fluxes over vegetated areas within an urban catchment. In urban areas, rain falling over impervious surfaces is directly transferred towards the drainage system in a time depending on the catchment characteristics, and drainage network geometry. If the rain falls over pervious and vegetated areas the runoff generation is driven by soil moisture content, which in turn is li…

Long term analysis of small desalination plant for potable water supply of tourist areas (in Sicily)

The main aim of this work is to gain information on the working conditions of a desalination plant in Sicily, on the costs of produced desalinated water and on the perspectives of new plants to be built in the island, in order to evaluate the long term performance of a desalination plant in a small island for potable water supply. At the same time, because the high operational costs, the work tries to provide green power alternatives for the plant as well. As a pilot we will consider the Lipari Island which has a MED-MVC (Multiple Effect Distillation- Mechanical Vapor Compression) plant. It is important to underline that even though the pilot refers to a Sicilian Island, the developed proce…

Generation of Natural Runoff Monthly Series at Ungauged Sites Using a Regional Regressive Model

Many hydrologic applications require reliable estimates of runoff in river basins to face the widespread lack of data, both in time and in space. A regional method for the reconstruction of monthly runoff series is here developed and applied to Sicily (Italy). A simple modeling structure is adopted, consisting of a regression-based rainfall–runoff model with four model parameters, calibrated through a two-step procedure. Monthly runoff estimates are based on precipitation, temperature, and exploiting the autocorrelation with runoff at the previous month. Model parameters are assessed by specific regional equations as a function of easily measurable physical and climate basin descriptors. Th…

Climate change and Ecotone boundaries: Insights from a cellular automata ecohydrology model in a Mediterranean catchment with topography controlled vegetation patterns

Abstract Regions of vegetation transitions (ecotones) are known to be highly sensitive to climate fluctuations. In this study, the Cellular-Automata Tree Grass Shrub Simulator (CATGraSS) has been modified, calibrated and used with downscaled future climate scenarios to examine the role of climate change on vegetation patterns in a steep mountainous catchment (1.3 km2) located in Sicily, Italy. In the catchment, north-facing slopes are mostly covered by trees and grass, and south-facing slopes by Indian Fig opuntia and grass, with grasses dominating as elevation grows. CATGraSS simulates solar radiation, evapotranspiration, and soil moisture in space and time. Each model cell can hold a sing…

Modeling the shrub encroachment in the Northern Chihuahuan desert Grasslands using a Cellular Automata model

Mappatura del deflusso annuo superficiale in Sicilia

Nella risoluzione di numerosi problemi pratici dell’idrologia delle acque superficiali è importante poter far affidamento su informazioni relative ai deflussi che siano contemporaneamente affidabili e diffuse sul territorio.La creazione di uno strumento capace di restituire il deflusso e soprattutto la portata che attraversa una determinata sezione di un corso d’acqua è di fondamentale importanza sia per la pianificazione delle risorse idriche in una data regione sia per l’individuazione delle possibili zone soggette al rischio della desertificazione. La stima del deflusso superficiale permette inoltre la determinazione dei concentrazione degli inquinanti, concentrati o diffusi, nei corpi i…

Mechanisms of shrub encroachment into Northern Chihuahuan Desert grasslands and impacts of climate change investigated using a cellular automata model

Arid and semiarid grasslands of southwestern North America have changed dramatically over the last 150 years as a result of woody plant encroachment. Overgrazing, reduced fire frequency, and climate change are known drivers of woody plant encroachment into grasslands. In this study, relatively sim- ple algorithms for encroachment factors (i.e., grazing, grassland fires, and seed dispersal by grazers) are proposed and implemented in the ecohydrological Cellular-Automata Tree Grass Shrub Simulator (CAT- GraSS). CATGraSS is used in a 7.3 km 2 rectangular domain located in central New Mexico along a zone of grassland to shrubland transition, where shrub encroachment is currently active. CATGraS…

The SESAMO early warning system for rainfall-triggered landslides

The development of Web-based information systems coupled with advanced monitoring systems could prove to be extremely useful in landslide risk management and mitigation. A new frontier in the field of rainfall-triggered landslides (RTLs) lies in the real-time modelling of the relationship between rainfall and slope stability; this requires an intensive monitoring of some key parameters that could be achieved through the use of modern and often low-cost technologies. This work describes an integrated information system for early warning of RTLs that has been deployed and tested, in a prototypal form, for an Italian pilot site. The core of the proposed system is a wireless sensor network coll…

MODELING THE INFLUENCE OF THE CLIMATE CHANGE ON THE VEGETATION PATTERN VARIATION USING A CELLULAR AUTOMATA MODEL

A spatially distributed and physically based tool to modelling rainfall-triggered landslides

Landslides are a serious threat to lives and property throughout the world. Over the last few years the need to provide consistent tools and support to decision-makers and land managers have led to significant progress in the analysis and understanding of the occurrence of landslides. The causes of landslides are varied. Multiple dynamic processes are involved in driving slope failures. One of these causes is prolonged rainfall, which affect slope stability in different ways. Water entering the ground beneath a slope always causes a rise of the piezometric surface, which in turn involves an increase of the pore-water pressure and a decrease of the soil shear resistance. For this reason, kno…

Hydrological and mechanical effects of roots in shallow landslide analysis: A physically-based approach

This study provides the first insights of a methodology for estimating the additional cohesion exercised by vegetation roots in a hillslope landslide analysis within a coupled ecohydrological-stability model. The existing coupled system is able to simulate the spatial distribution and temporal dynamics of Factor of Safety (FS) as a function of soil moisture dynamics. The model takes into account the hydrological effects of vegetation which, through the root water uptaking, contributes in reducing the soil water content and, thus, in increasing the slope stability. The additional mechanical root cohesion is estimated in a Fiber Bundle Model (FBM) framework that allows for the evaluation of t…

Future Climate Forcings and Olive Yield in a Mediterranean Orchard

The olive tree is one of the most characteristic rainfed trees in the Mediterranean region. Observed and forecasted climate modifications in this region, such as the CO2 concentration and temperature increase and the net radiation, rainfall and wind speed decrease, will likely alter vegetation water stress and modify productivity. In order to simulate how climatic change could alter soil moisture dynamic, biomass growth and fruit productivity, a water-driven crop model has been used in this study. The numerical model, previously calibrated on an olive orchard located in Sicily (Italy) with a satisfactory reproduction of historical olive yield data, has been forced with future climate scenar…

Quality management in meteoclimatic variables monitoring

Green roof effects on the rainwater response in the Mediterranean area: first results of a Sicilian case study

<p>Over the last decades, we have been witnessing an increasing frequency of urban floods often attributed to the interaction between intensification of rainfall extremes due to climate change and increasing urbanization. Consequently, many studies have been trying to propose different new alternatives to mitigate ground effects of ever more frequent and severe extreme rainfall events in a context of growing urbanization, such as rain gardens, green roofs, permeable parking lots, etc., which are commonly referred to as green infrastructures.</p><p>With this regard, one of the most promising mitigation solutions is represented by multilayer green roo…

A PCA-based clustering algorithm for the identification of stratiform and convective precipitation at the event scale: an application to the sub-hourly precipitation of Sicily, Italy

AbstractUnderstanding the structure of precipitation and its separation into stratiform and convective components is still today one of the important and interesting challenges for the scientific community. Despite this interest and the advances made in this field, the classification of rainfall into convective and stratiform components is still today not trivial. This study applies a novel criterion based on a clustering approach to analyze a high temporal resolution precipitation dataset collected for the period 2002–2018 over the Sicily (Italy). Starting from the rainfall events obtained from this dataset, the developed methodology makes it possible to classify the rainfall events into f…

Performances of GPM satellite precipitation over the two major Mediterranean islands

Reliable and accurate precipitation measurement or estimation is crucial for disaster monitoring and water resource management. However, obtaining accurate high-resolution precipitation fields is still a challenging task for scientists and practitioners, especially in the poorer region of the world. Nowadays the scientific community expects significant improvements in precipitation monitoring by the continuous technological evolution of satellite-rainfall estimate systems which are able to produce data with global coverage and thus can provide low-cost information even in scarcely populated areas or places where for economic reasons ground measures are missing. The most recent satellite mis…

EHSM: a new conceptual model for daily streamflow simulation under ecohydrological framework

A parsimonious conceptual lumped model is presented here with the aim of simulating daily streamflow in semi-arid areas. The model is able to reproduce surface and sub-surface runoff, soil moisture dynamics and evapotranspirative fluxes, averaged over a basin starting from daily time series of rainfall and temperature and from the initial value of soil. The rainfall is partioned in two components: the first, which interests a totally impermeable area, is routed directly on a superficial linear reservoir, while the second passes through permeable soil. If the rainfall input exceeds the soil storage capacity, which is a function of soil moisture at that specific time, this saturation excess i…

Strategies investigation in using artificial neural network for landslide susceptibility mapping: application to a Sicilian catchment

Susceptibility assessment of areas prone to landsliding remains one of the most useful approaches in landslide hazard analysis. The key point of such analysis is the correlation between the physical phenomenon and its triggering factors based on past observations. Many methods have been developed in the scientific literature to capture and model this correlation, usually within a geographic information system (GIS) framework. Among these, the use of neural networks, in particular the multi-layer perceptron (MLP) networks, has provided successful results. A successful application of the MLP method to a basin area requires the definition of different model strategies, such as the sample selec…

Impact of hydrologically driven hillslope erosion and landslide occurrence on soil organic carbon dynamics in tropical watersheds

The dynamics of soil organic carbon (SOC) in tropical forests play an important role in the global carbon (C) cycle. Past attempts to quantify the net C exchange with the atmosphere in regional and global budgets do not systematically account for dynamic feedbacks among linked hydrological, geomorphological, and biogeochemical processes, which control the fate of SOC. Here we quantify effects of geomorphic perturbations on SOC oxidation and accumulation in two adjacent wet tropical forest watersheds underlain by contrasting lithology (volcaniclastic rock and quartz diorite) in the Luquillo Critical Zone Observatory. This study uses the spatially-explicit and physically-based model of SOC dy…

Soil moisture limiting olive orchard evapotranspiration

Two years of field data concerning soil moisture dynamics and water vapor fluxes over a rainfed olive orchard in Sicily are presented here in order to understand how climate, seasonality, water availability and farming practices drive evapotranspiration in such a peculiar Mediterranean vegetation. Soil moisture has been measured in two different points characterized by a uniformly sandy soil and at multiple depths up to 1.2 m. The observed dynamics are driven by rainfall inputs, which are frequent during the winter season and rare during the growing season, and by vegetation uptakes, which deplete the water stored in the soil. The top layers soil moisture status is much more time dependent …

Data Resolution Effects on Landslides Hazard and Susceptibility Assessment of Puerto Rico

Development of a regional flood frequency analysis using L-Moments approach for gauged and ungauged catchments of Sicily. Atti del International Workshop on Hydrological Extremes “Observing and modelling exceptional floods and rainfalls”.

Produttività dell’ulivo e dinamiche di umidità del suolo

Spatial distribution of temperature trends in Sicily

Climate change resulting from the enhanced greenhouse effect is expected to have great impacts on hydrological cycle and consequently on ecosystems. The effects of climate variability have direct implications on water management, as water availability is related to changes in temperature and precipitation regimes. At the same time, this kind of alterations drives ecological impacts on flora and fauna. For these reasons, many studies have been carried out to investigate the existence of some tendency in temperature and/or precipitation series in different geographic domains. In order to verify the hypothesis of temperature increase in Sicily (Italy), temperature data from about 80 spatially …

CAMBIAMENTI CLIMATICI E EROSIONE IDRICA: UN’APPLICAZIONE AL BACINO DEL COMUNELLI, SICILIA

Influenza delle condizioni meteorologiche sulla propagazione elettromagnetica ed effetti sul servizio di telefonia mobile

Analisi della affidabilità dei database pluviometrici globali a scala locale. Applicazione al territorio siciliano

Negli ultimi anni i sistemi di misurazione e di stima delle precipitazioni, sono stati arricchiti dalla possibilità di ottenere stime attraverso dati acquisiti da sensori satellitari. I prodotti di stima così ottenuti risultano comunque spesso fortemente distorti. Per tale ragione le stime sulla base di soli dati satellitari, vengono ulteriormente elaborate attraverso l'utilizzo di dataset che raccolgono dati di precipitazione provenienti da reti pluviografiche al fine di ridurre la distorsione che caratterizza i dati satellitari. È auspicabile che questi dataset siano quanto più precisi al fine di fornire dati adatti alla correzione dei dati satellitari e in particolare alla riduzione dell…

Detecting hydrological changes through conceptual model

Natural changes and human modifications in hydrological systems coevolve and interact in a coupled and interlinked way. If, on one hand, climatic changes are stochastic, non-steady, and affect the hydrological systems, on the other hand, human-induced changes due to over-exploitation of soils and water resources modifies the natural landscape, water fluxes and its partitioning. Indeed, the traditional assumption of static systems in hydrological analysis, which has been adopted for long time, fails whenever transient climatic conditions and/or land use changes occur. Time series analysis is a way to explore environmental changes together with societal changes; unfortunately, the not disting…

Caratterizzazione dei processi di siccità e di desertificazione su scala regionale

UN SISTEMA DI EARLY WARNING RELATIVO AL RISCHIO IDRAULICO FLUVIALE IN AMBITO URBANO BASATO SULLA DEFINIZIONE DI SCENARI DI EVENTO: IL CASO STUDIO DI PALERMO

La progressiva espansione delle aree urbanizzate, osservata negli ultimi decenni a scala globale, ha profondamente modificato i processi di formazione e trasferimento del deflusso superficiale ed ha portato ad un considerevole aumento degli elementi esposti a rischio alluvioni. I cambiamenti climatici in atto hanno inoltre indotto un’intensificazione degli eventi meteorici, con un probabile incremento della frequenza e della severità di eventi estremi in ambito urbano come urban flood e fash flood. Secondo una recente stima da parte della Commissione Europea [1], nel periodo 1980-2017 i danni causati da disastri naturali hanno superato i 500 milioni di euro, di cui il 90% dovuti ad eventi i…

Procedures for historical data characterization

Analitical deriving of the field capacity through soil bundle model

The concept of field capacity as soil hydraulic parameter is widely used in many hydrological applications. Althought its recurring usage, its definition is not univocal. Traditionally, field capacity has been related to the amount of water that remains in the soil after the excess water has drained away and the water downward movement experiences a significant decresase. Quantifying the drainage of excess of water may be vague and several definitions, often subjective, have been proposed. These definitions are based on fixed thresholds either of time, pressure, or flux to which the field capacity condition is associated. The flux­based definition identifies the field capacity as the soil m…

Relationship Between Extreme Rainfall and Surface Temperature in Sicily (Italy)

The study of the relationship between extreme rainfall events and surface temperature represents an important issue in hydrology and meteorology and it could be of capital importance for evaluating the effect of global warming on future precipitation. Various approaches have been tested across different parts of the world, and, in many cases, it has been observed an intensification of precipitation with increasing temperature consistently with the thermodynamic Clausius-Clapeyron relation (CC-rate of 6-7% °C-1), according to which a warmer atmosphere is capable of holding more moisture. Nevertheless, in different locations, the scaling rate between temperature and extreme precipitation has …

Derivation of critical rainfall thresholds for landslide

Rainfall is the primary trigger of shallow landslides that can cause fatalities and economic losses in many areas of the world. For this reason, determining the rainfall amount responsible for landslide occurrence is important, and may contribute to mitigate the related risk. In particular, the definition of critical rainfall-triggering thresholds for landslide is one of the most used approach, which is based on empirical methods. The creation of the rainfall-landslide database represents one of the main efforts in this kind of analysis, which requires a perfect agreement between the rainfall and landslide information in terms of timing. This requirement is easily obtained in the case of th…

Modeling belowground water table fluctuations in the Everglades

[1] Humid lands, such as riparian zones, peatlands, and unsubmerged wetlands, are considered among the most biologically diverse of all ecosystems, providing a bountiful habitat for a large number of plant and animal species. In such ecosystems, the water table dynamics play a key role in major ecohydrological processes. The aim of the present study is to test with field data a recent analytical model for the estimation of the long-term probability distribution of the belowground water table position in groundwater-dependent environments. This model accounts for stochastic rainfall and processes such as infiltration, root water uptake, water flow from/to an external water body, and capillar…

Smart Data Blending Framework to Enhance Precipitation Estimation through Interconnected Atmospheric, Satellite, and Surface Variables

Accurate precipitation estimation remains a challenge, though it is fundamental for most hydrological analyses. In this regard, this study aims to achieve two objectives. Firstly, we evaluate the performance of two precipitation products from the Integrated Multi-satellitE Retrievals for Global Precipitation Measurement (GPM-IMERG) for Sicily, Italy, from 2016 to 2020 by a set of categorical indicators and statistical indices. Analyses indicate the favorable performance of daily estimates, while half-hourly estimates exhibited poorer performance, revealing larger discrepancies between satellite and ground-based measurements at sub-hourly timescales. Secondly, we propose four multi-source me…

Individuazione dei trend di pioggia per la Sicilia utilizzando un approccio multiscala basato sulla regressione a quantili

Uno degli argomenti più attuali e controversi è se, negli ultimi decenni, le piogge intense siano diventate più frequenti come possibile effetto dei cambiamenti climatici. La centralità del tema è giustificata dalle gravi conseguenze che l’intensificarsi di questi fenomeni, in frequenza e magnitudo, potrebbe indurre a livello sociale ed economico. Basti pensare alle “flash flood”, spesso causate da eventi di precipitazione con una forte componente convettiva, che in ambito urbano mettono in crisi i sistemi di drenaggio arrecando rilevanti danni e, purtroppo, anche perdite di vite umane. La Sicilia è stata spesso monitorata con l’obiettivo di individuare delle mutazioni significative del cic…

Modeling the mechanical and hydrological controls of vegetation in shallow landslides

Rainfall Induced Landslides in Puerto Rico

Landslides are a major geologic hazard in the United States, typically triggered by rainfall, earthquakes, volcanoes and human activity. Rainfall-induced landslides are the most common type in the island of Puerto Rico, with one or two large events per year. We performed an island-wide determination of static landslide susceptibility and hazard assessment as well as dynamic modeling of rainfall-induced shallow landslides in a particular hydrologic basin. Based on statistical analysis of past landslides, we determined that reliable prediction of the susceptibility to landslides is strongly dependent on the resolution of the digital elevation model (DEM) employed and the reliability of the ra…

CONFRONTO TRA DIVERSE TECNICHE DI INTERPOLAZIONE DI DATI DI PRECIPITAZIONE E TEMPERATURA PER LA CREAZIONE DI DATASET DI SERIE STORICHE MENSILI COMPLETE DI VARIABILI CLIMATICHE

Tecniche di analisi spaziale per la ricostruzione delle serie storiche di dati climatici

Effetto della distribuzione temporale della precipitazione sull’innesco di movimenti superficiali a scala di bacino

USING A X-BAND WEATHER RADAR FOR AN URBAN AREA EARLY WARNING SYSTEM AND THE STUDY OF PRECIPITATION DYNAMICS.

The development and availability of X-band radar instruments occurred in the last years, provides the scientific community of an important tool for the study, the characterization and the operational usage of detailed precipitation information. The hydrology laboratory of the Department of Civil, Environmental, Aerospace Engineering, and Materials (DICAM) at the University of Palermo, has installed a X-band weather radar in the urban area of Palermo (Italy) along with a set of advanced auxiliary instruments that help on exploiting the precipitation information. A raingauge network of 18 tipping bucket gauges spread over the observed area is available for the calibration of precipitation map…

Influence of soil erosion and landslide occurrence on the CO2 exchange with the atmosphere at the Luquillo Critical Zone Observatory, Puerto Rico

Tropical rainforests play a significant role in the global carbon (C) cycle. The Luquillo Critical Zone Observatory (LCZO) in Puerto Rico is characterized by intense erosion and landslide occurrence, which have been historically influenced by human activity and land use change, and drive the redistribution and burial of soil organic C (SOC) across the landscape. Estimates of regional C budgets do not systematically account for linkages between hydrological, geomorphological, and biogeochemical processes, which control the fate of eroded SOC. We quantify the impacts of erosion and rainfall-triggered landslides on SOC oxidation and accumulation at the Mameyes and Icacos watersheds. We develop…

Effect of raster resolution and polygon-conversion algorithm on landslide susceptibility mapping

The choice of the proper resolution in landslide susceptibility mapping is a worth considering issue. If, on the one hand, a coarse spatial resolution may describe the terrain morphologic properties with low accuracy, on the other hand, at very fine resolutions, some of the DEM-derived morphometric factors may hold an excess of details. Moreover, the landslide inventory maps are represented throughout geospatial vector data structure, therefore a conversion procedure vector-to-raster is required.This work investigates the effects of raster resolution on the susceptibility mapping in conjunction with the use of different algorithms of vector-raster conversion. The Artificial Neural Network t…

Sensitivity of extreme rainfall to temperature in semi-arid Mediterranean regions

Abstract Warmer air has the potential to hold more water vapour and, therefore, to provide more water to rainfall events. Studying the relationship between rainfall and temperature represents an emerging issue in hydrology and meteorology, since it can be considered fundamental for evaluating the effects of global warming on future precipitation. Various approaches have been tested across different parts of the world, in many cases observing an intensification of extreme precipitation at higher temperatures consistent with the well-known thermodynamic Clausius-Clapeyron relation (CC-scaling rate of 6–7%°C−1). However, at different locations for hourly time-scales, the temperature-extreme ra…

Assessing the hydrological changes due to land use alterations

The increase of urbanized areas and, consequently, of the impervious surfaces in land-use distributions may have important implications on the basin hydrological response. As a direct impact, the increase of cemented areas reduces the available storage volume for water in the watershed, which in turn exacerbates the runoff generation. Additionally, drainage pathways can be altered and the travel time to the watershed outlet considerably speeded up, with impacts on the hydrograph characteristics. The complex interactions among different hydrological processes make the estimations of the hydrological changes highly non linear. The aim of this work is using an advanced physically-based and dis…

Exploiting the topographic information in a PDM-based conceptual hydrological model

In this work, a conceptual lumped model was developed to simulate runoff and analyze hydrological processes with the goal of incorporating the morphological information into a probability-distributed model (PDM). PDMs usually describe the process of runoff generation as the result of soil saturation excess caused by precipitation with soil storage capacity represented by a spatially distributed quantity and described by a probability distribution. The proposed model, called topography-based probability distributed model (TOPDM), based on a simple water balance whose components are basin soil moisture storage, precipitation, drainage to groundwater, evapotranspiration, and Dunnian and Horton…

Implications of terrain resolution on modeling rainfall-triggered landslides using a TIN- based model

Abstract This study employs a distributed eco-hydrological-landslide model, the tRIBS-VEGGIE-Landslide, to evaluate the influence of terrain resolution on the hydro-geomorphological processes involved in slope stability analysis. The model implements a Triangulated Irregular Network (TIN) to describe the topography starting from a grid-DEM. Five grid-DEM resolutions of the case study basin, i.e., 10, 20, 30 and 70 m, are used to derive the corresponding TINs. The results show that using irregular meshes reduces the loss of accuracy with coarser resolutions in the derived slope distribution in comparison to slope distributions estimated from the original grid-based DEM. From a hydrological p…

Annual runoff regional frequency analysis in Sicily

Abstract This paper performs annual runoff frequency analysis in Sicily, Italy using the index runoff method. Homogeneous regions, not necessarily defined by geographical boundaries but sharing common features from a morphologic and climatic standpoint, have been identified. For each region a single probability distribution function can be fitted to the available annual runoff data scaled by the index runoff. Starting from an initial dataset of 105 hydrometric stations, 57 stations have been selected using heuristic criteria associated with the Hosking and Wallis’s discordancy measure. The Mantel tests have been then applied to find out the physical and morphological parameters best correla…

Development of a regional flood frequency analysis using L-Moments approach for gauged and ungauged catchments of Sicily

Rainfall Induced Landslides in Puerto Rico

Combining single polarization X-band radar and ground devices for hydrological applications

Recently, the Department of Civil, Environmental, Aerospace Engineering, and Materials (DICAM) of the University of Palermo (Italy) has installed several devices for the monitoring of precipitation for the urban area of Palermo. These devices include a single polarization X-band weather radar, a rain gauge network spread over the urban area, and a laboratory site where advanced precipitation devices (an optical disdrometer, a weight rain gauge, and a weather station) are available. Given the ensemble of measurements retrieved by sensors, a set of models for the combination of data has been developed in order to exploit their joint usage. The disdrometer information have been exploited for t…

Optical techniques for river flow monitoring: an automatic procedure for the identification of the best video sequence to process by LS-PIV technique

Technological advances over last decades gave an innovative impulse to the development of new streamflow measurements techniques, especially regarding remote flow monitoring methods that allow for non-intrusive measurements. The most widely used image-based techniques are the optical ones, such as Large-Scale Particle Image Velocimetry (LS-PIV) and Large-Scale Particle Tracking Velocimetry (LS-PTV). The dynamic movement of tracers floating on the water surface of a river is recorded, and the resulting videos are processed by applying a statistical cross-correlation analysis to detect the most probable frame-by-frame displacement, finally deriving the surface velocity field. To obtain river …

Tecniche GIS per il calcolo del bilancio idrologico delle acque superficiali

The relationship between precipitation depth and weather circulation patterns over Sicily

Some weather circulation patterns (WPs) derived by the UK Met Office and defining a certain type of atmospheric circulation over Europe have been recently used to analyze the relationship of the regional UK precipitation and drought with respect to the atmospheric circulation over Europe (Richardson et al. 2018). In this study, we attempt to find out one or more relationships between precipitation depth and weather patterns over a non UK-centred domain, such as Sicily (Italy), which is characterized by a totally different climate as compared to the climate of UK. Since the island has been affected by many floods in the last years, occurred as a consequence of extreme rainfall events, it wou…

IMPLEMENTAZIONE DI UN ALGORITMO DI CLUSTERING PER L’IDENTIFICAZIONE DELLE PRECIPITAZIONI STRATIFORMI E CONVETTIVE ALLA SCALA D’EVENTO: UN’APPLICAZIONE ALLE PRECIPITAZIONI SUB-ORARIE DELLA SICILIA

Modellazione eco-idrologica del ruolo delle radici nell'analisi di stabilità di un versante

Evaluating the performances of an ecohydrological model in semi-arid river basins

The EHSM (EcoHydrological Streamflow Model) is a conceptual lumped model aimed to daily streamflow simulation. The model, processing daily rainfall and reference evapotranspiration at the basin scale, reproduces surface and subsurface runoff, soil moisture dynamics and actual evapotranspiration fluxes. The key elements of this numerical model are the soil bucket, where rainfall, evapotranspiration and leakage drive soil moisture dynamics, and two linear reservoirs working in parallel with different characteristic response times. The surface reservoir, able to simulate the fast response of the basin, is fed by rain falling on impervious area and by runoff generated with excess of saturation …

Stochastic assessment of climate impacts on hydrology and geomorphology of semiarid headwater basins using a physically based model

Hydrologic and geomorphic responses of watersheds to changes in climate are difficult to assess due to projection uncertainties and nonlinearity of the processes that are involved. Yet such assessments are increasingly needed and call for mechanistic approaches within a probabilistic framework. This study employs an integrated hydrology-geomorphology model, the Triangulated Irregular Network-based Real-time Integrated Basin Simulator (tRIBS)-Erosion, to analyze runoff and erosion sensitivity of seven semiarid headwater basins to projected climate conditions. The Advanced Weather Generator is used to produce two climate ensembles representative of the historic and future climate conditions f…

A local post-retrieval tool for satellite precipitation estimates

As illustrated by several literature case studies spread around di erent geographic locations, satellite precipi- tation estimates, obtained by means of consolidated algorithms, often result being considerably biased. Moreover observed bias is related to geographic location since particular features such as latitude, presence of coastal areas and climatological and weather regime, a ect performances of satellite estimates. Bias adjusted products that make use of global ground-based precipitation estimates, are available as well but still these datasets may show a relevant bias level. In this study a procedure to bias-adjust satellite precipitation estimates has been devel- oped for the loca…

Basin-Scale Water Resources Assessment in Oklahoma under Synthetic Climate Change Scenarios Using a Fully Distributed Hydrologic Model

Climate change resulting from the enhanced greenhouse effect is expected to have significant implications for the hydrological cycle. Several studies have pointed out the importance of basin-scale investigations for determining regional impacts on water resources, including the effects of floods and droughts. In this study, a fully distributed hydrologic model is used to assess the potential impacts of climate change on water availability in a basin in Oklahoma United States . With this aim, the hydrologic model was applied for current conditions as well as under the hypotheses of climate variations represented by scenarios consistent with a climatic trend analysis generated using a stochas…

Potential implications of climate change and urbanization on watershed hydrology

Abstract This paper proposes a modeling framework able to analyze the alterations in watershed hydrology induced by two recurrent drivers for hydrological changes: climate change and urbanization. The procedure is based on the coupling of a stochastic weather generator with a land use change model for the generation of some hypothetical scenarios. The generated scenarios are successively used to force a physically-based and spatial distributed hydrological model to reconstruct the basin response under different conditions. Several potential climate alterations are simulated by imposing negative and positive variations in the mean annual precipitation and a simultaneous temperature increase.…

DORA algorithm for network flow models with improved stability and convergence properties

A new methodology for the solution of shallow water equations is applied for the computation of the unsteady-state flow in an urban drainage network. The inertial terms are neglected in the momentum equations and the solution is decoupled into one kinematic and one diffusive component. After a short presentation of the DORA (Double ORder Approximation) methodology in the case of a single open channel, the new methodology is applied to the case of a sewer network. The transition from partial to full section and vice versa is treated without the help of the Preissmann approximation. The algorithm also allows the computation of the diffusive component in the case of vertical topographic discon…

Ricostruzione delle curve di durata mediante un nuovo approccio ecoidrologico

Le curve di durata delle portate forniscono un importante sintesi dei processi idrologici più rilevanti occorrenti a scala di bacino. Sebbene vengano tipicamente ottenute a partire dalle osservazioni idrometriche, uno dei temi più rilevanti in idrologia è proprio la loro ricostruzione anche in bacini non strumentati. A tal proposito sono stati sviluppati negli ultimi anni svariati approcci teorici, alcuni dei quali meritano particolare attenzione per la loro semplicità di applicazione e accuratezza dei risultati mostrati. La curva di durata viene spesso disaggregata in due componenti: una componente veloce di deflusso superficiale ed una componente lenta di deflusso subsuperficiale. Un rece…

Spatial distribution of temperature trends in Sicily

Modelling flows duration curves in Mediterranean river basins through an ecohydrological approach

The flow duration curve, representing the relationship between magnitude and frequency of streamflows in a basin, provides an important synthesis of the relevant hydrological processes occurring at the basin scale. It is typically obtained from field observations and, since most of the geographical areas of the world still lack suitable streamflow observations, its reconstruction in ungauged river basins is certainly an open and relevant issue in the hydrological literature. Different theoretical approaches have been developed in recent years, and in particular, a novel ecohydrological framework has provided considerable results. The aim of this study is to test with field data, a recent an…

Integration of fuzzy logic and image analysis for the detection of gullies in the Calhoun Critical Zone Observatory using airborne LiDAR data

Abstract The entire Piedmont of the Southeastern United States, where the Calhoun Critical Zone Observatory (CCZO) is located, experienced one of the most severe erosive events of the last two centuries. Forested areas were cleared to cultivate cotton, tobacco, and other crops during the nineteenth and early twentieth century and these land use changes, together with intense rainfalls, initiated deep gullying. An accurate mapping of these landforms is important since, despite some gully stabilization and reforestation efforts, gullies are still major contributors of sediment to streams. Mapping gullies in the CCZO area is hindered by the presence of dense canopy, which precludes the identif…

Creazione di un database per l’applicazione di modelli empirici di analisi di dissesto idrogeologico da precipitazione nel territorio Siciliano.

La previsione di fenomeni di dissesto idrogeologico è uno strumento essenziale di supporto alle decisioni per una corretta pianificazione del territorio. Tra tali fenomeni quelli franosi possono assumere dimensioni particolarmente rilevanti. Il fattore scatenante più ricorrente nella gran parte dei casi di frane documentate e’ costituito dalle precipitazioni. La letteratura scientifica propone diverse metodologie di analisi volte a fornire strumenti di pre-allarme in vista di un evento meteorico critico o di derivazione di mappe tematiche delle aree a maggiore suscettibilità franosa. I modelli empirici per la derivazione di soglie pluviometriche critiche di innesco risultano tra i più utili…

Distribuzione spaziale dei trend pluviometrici in Sicilia (1921-2000)

An Artificial Intelligence–Based Blending of Satellite products across Mediterranean Island of Sicily, Italy using GPM-IMERG V06 Final Run

Precipitation is the key input variable to hydrological models and its monitoring plays a significant role in water resources planning and improving flood and drought forecasting, also under climate change impacts. In recent years, many precipitation satellite products have been developed and released to the public; among these, the Integrated Multi-satellitE Retrievals from Global Precipitation Measurement (IMERG) is designed to address limitations and uncertainties related to traditional methods. The primary purpose of this study is to provide a comprehensive assessment of precipitation estimates retrieved from the IMERG v6 Final Run over the Mediterranean island of Sicily (Italy) at dail…

Landslide susceptibility mapping: a comparison of logistic regression and neural networks methods in a small sicilian catchment

Trend analysis of climatic indexes in Sicily

Modelling the shrub encroachment in a grassland with a Cellular Automata Model

Abstract. Arid and semi-arid grasslands of southwestern North America have changed dramatically over the last 150 years as a result of shrub encroachment, i.e. the increase in density, cover and biomass of indigenous shrubby plants in grasslands. Numerous studies have documented the expansion of shrublands in the southwestern American grasslands; in particular shrub encroachment has occurred strongly in part of the northern Chihuahuan desert since 1860. This encroachment has been simulated using an ecohydrological Cellular Automata model, CATGraSS. It is a spatially distributed model driven by spatially explicit irradiance and runs on a fine-resolution gridded domain. Plant competition is m…

Modeling the juniper encroachment in the western north America grasslands with a Cellular Automata model

VALUTAZIONE DEL POTENZIALE TECNICO ECONOMICO DELL’ EOLICO OFFSHORE IN SICILIA MEDIANTE TECNICHE GIS

Olive yield as a function of soil moisture dynamics

This study introduces a water-driven crop model aiming to quantitatively link olive yield to climate and soil moisture dynamics using an ecohydrological approach. A mathematical model describing soil moisture, evapotranspiration and assimilation dynamics of olive orchards is developed here. The model is able to explicitly reproduce two different hydroclimatic phases in Mediterranean areas: the well-watered conditions in which evapotranspiration and assimilation assume their maximum values and the real conditions where the limitations induced by soil moisture availability are taken into account. Annual olive yield is obtained by integrating the carbon assimilation during the growing season, …

The use of soil water retention curve models in analyzing slope stability in differently structured soils

Abstract This study analyzes whether and at what rate the parameterization of the Soil Water Retention Curve (SWRC) affects the analysis of shallow slope stability for differently structured unsaturated soils. Advanced empirical or physically-based equations of SWRCs have been proposed in literature to describe soil systems characterized by the so-called bimodal porous domain. In unsaturated soils, SWRC affects the stability assessment in two ways. It influences the resistance properties in terms of shear strengths, which depend on the soil water suction; and it affects the hydrological process modeling (e.g. infiltration) directly influencing soil moisture patterns and indirectly influenci…

Modeling the role of climate change on small-scale vegetation patterns in a Mediterranean basin using a Cellular Automata model

Predicting vegetation response in regions of ecotone transition under a changing climate is a among grand challenges in ecohydrology. In a small basin (1.3 sq km) in Sicily, Italy, where north-facing slopes are characterized by Quercus (tree), and south-facing slopes by Opuntia ficus-indaca (evergreen perennial species drought tolerant) and grasses we use an ecohydrological Cellular-Automaton model (CATGraSS) of vegetation coexistence driven by rainfall and solar radiation with downscaled future climate to examine the role of climate change on vegetation patterns. In the model, each cell can hold a single plant type or can be bare soil. Plant competition is modeled explicitly by keeping tra…

Analisi statistica della velocità del vento nel Canale di Sicilia

MODELING THE TERRAIN EVOLUTION AT BASIN SCALE: THE GEOMORPHIC COMPONENT OF TRIBS HYDROLOGICAL MODEL

Classification of Extreme Rainfall for a Mediterranean Region by Means of Atmospheric Circulation Patterns and Reanalysis Data

AbstractThe atmospheric circulation can be recognized as one of the causes of severe rainfall events occurrence. Such events, especially when are characterized by short durations and high intensities, result in flood events in the Mediterranean area. It is very important to understand how these heavy rainfall events, which can be usually identified with convective rainfall, are related to the different types of atmospheric circulation. In order to do this, some weather circulation patterns (WPs), which have been derived for the Europe, have been first connected with the rainfall annual maxima (AMAX) recorded over the Sicily. The analyses allowed to identify those WPs that are more likely to…

THE ROLE OF HYDROLOGICAL PROCESSES ON ENHANCED WEATHERING FOR CARBON SEQUESTRATION IN AGRICULTURAL SOILS

With the aim to face climate change, some NCS (Natural Climate Solutions) are currently studied given their capability to sequester carbon from the atmospheric CO2, by means of some natural processes, and to store it within oceans, plants, soil, or other terrestrial environments. Among all the existing NCS, Enhanced Weathering (EW) acts in speeding up the chemical weathering that naturally occurs in soils. This is achieved by amending soils with crushed highly reactive silicate minerals, such as forsterite, better known as olivine. In general, EW reactions are faster at high temperature and soil water content and low soil pH, demonstrating that the most suitable places in the world to apply…

GIS AND REMOTE SENSING IN HYDROLOGY: SELECTED PRACTICAL APPLICATIONS

Caractèrisation des processus de seècheresse et de désertification à l'échelle régionale

Using the hierarchical modeling approach to derive spatial distribution of precipitation and temperature datasets. A case study for the area of Sicily (Italy).

The interest for spatial interpolating climatic variables available by means of point measurements, as precipitation and temperature, arises from different needs, ranging from their usage for hydrological models to the reconstruction of climatic atlas of spatially distributed data. In some areas the spatial distribution of these variables can be related to the extremely variable morphology of the area. While simple deterministic interpolation methods usually produce just the spatial distribution of the variable of interest, implicitly relying on the spatial autocorrelation and manually tuning a few parameters, more complex statistical models, are able to derive the uncertainty associated wi…

Influence of surface roughness in hydrological response of semiarid catchments

Abstract Here, an investigation has been carried out in order to understand the influence of the surface roughness in the definition of the hydrological response of semiarid catchments. Following a previous study of one of the authors, a modified version of TOPMODEL is used, in which the convolution routing procedure has been extended to the hillslopes by specifying the routing velocity for each pixel of the watershed. These velocities have been linked to the watershed land use through the different surface roughness whose coefficients has been derived on the basis of Engman's table. In this paper, roughness coefficient distributions are expressed as function of a unique value treated as a …

Comparison between storm tracking analysis techniques in urban area based on high resolution raingauge data

GIS AND REMOTE SENSING IN HYDROLOGY: SELECTED PRACTICAL APPLICATIONS. Proceedings of the ECO-GEOWATER conference - GIS for International river basin management.

ANALISI DEI TREND DI INDICI CLIMATICI IN SICILIA

The Role of Hydrological Processes on Enhanced Weathering for Carbon Sequestration in Cropland Areas: An Application to Italy

Aiming at facing climate change, some CDR (Carbon Dioxide Removal) techniques are currently studied given their capability to sequester carbon from the atmospheric CO2 and to store it within oceans, plants, soil, or other terrestrial environments. Among them, Enhanced Weathering (EW), that acts in speeding up the chemical weathering naturally occurring in soils through the amendments of highly reactive silicate minerals, is referred to as one of the most promising. Hot and humid climates provide the best conditions for EW, since reactions are faster at high temperature, high soil water content and low soil pH. This study presents a dynamic mass balance model that explores ecohydrological, b…

On the use of LSPIV-based free software programs for the monitoring of river: testing the PIVlab and the FUDAA-LSPIV with synthetic and real image sequences

<p>The development of new image-based techniques is allowing a radical change in the environmental monitoring field. The fundamental characteristics of these methods are related to the possibility of obtaining non-intrusive measurements even in adverse circumstances, such as high flow conditions, which may seriously threaten the operators’ safety conditions in traditional approaches.</p><p>Optical techniques, based on the acquisition, analysis and elaboration of sequences of images acquired by digital cameras, are aimed at a complete characterization of the river instantaneous surface velocity field, through the analysis of a floating…

The role of hydrology on enhanced weathering for carbon sequestration II. From hydroclimatic scenarios to carbon-sequestration efficiencies

Abstract Enhanced weathering (EW) scenarios are analyzed using the model presented in Cipolla et al. (2020). We explore the role of different hydroclimatic forcing on carbon-sequestration efficiencies. We also investigate whether increasing soil carbon content improves weathering conditions. We link olivine weathering rates to pH variations and quantify the suitability of hydroclimatic regimes to EW, based on rainfall intensity and frequency. The results show that the amount of CO 2 reacting with olivine and ending up in solution in the form of HCO 3 − and CO 3 2 − increases with mean annual precipitation (MAP) up to 2000 mm, but then tapers off for higher MAPs. On the contrary, the sequest…

Analisi frattale dei reticoli idrografici estratti automaticamente da DEM

Influence of serial correlation on climatic variables trends analysis in Sicily

Coupled stability and eco-hydrological model to predict shallow landslides

Climate changes' effects on vegetation water stress in Mediterranean areas

Many recent studies have demonstrated that CO(2) increase is driving the climate in Mediterranean areas towards important changes, mainly represented by a temperature increase and a contemporaneous rainfall reduction. Starting from this premise, the primary aim of the present study is to investigate the effects of potential climatic changes on vegetational stress in Mediterranean ecosystems. Particular attention is here focussed only on the plants' water stress in water controlled ecosystems, mainly related to soil water balance. The interactions among climate, soil and vegetation are evaluated numerically by means of an ecohydrological model. In this work, different future climatic scenari…

Investigating reservoir sediment and watershed erosion using the WEPP model

Effect of DEM resolution and threshold area on the hydrologic response at catchment scale

Optical Methods for River Monitoring: A Simulation-Based Approach to Explore Optimal Experimental Setup for LSPIV

Recent advances in image-based methods for environmental monitoring are opening new frontiers for remote streamflow measurements in natural environments. Such techniques offer numerous advantages compared to traditional approaches. Despite the wide availability of cost-effective devices and software for image processing, these techniques are still rarely systematically implemented in practical applications, probably due to the lack of consistent operational protocols for both phases of images acquisition and processing. In this work, the optimal experimental setup for LSPIV based flow velocity measurements under different conditions is explored using the software PIVlab, investigating perfo…

Parameter Uncertainty in Shallow Rainfall-triggered Landslide Modeling at Basin Scale: A Probabilistic Approach

Abstract This study proposes a methodology to account for the uncertainty of hydrological and mechanical parameters in coupled distributed hydrological-stability models for shallow landslide assessment. A probabilistic approach was implemented in an existing eco-hydrological and landslide model by randomizing soil cohesion, friction angle and soil retention parameters. The model estimates the probability of failure through an assumed theoretical Factor of Safety (FS) distribution, conditioned on soil moisture content. The time-dependent and spatially distributed FS statistics are approximated by the First Order Second Moment (FOSM) method. The model was applied to the Rio Mameyes Basin, loc…

Spatial interpolation methods based on the use of elevation data

Modeling the hydrological and mechanical effect of roots in shallow landslide analysis

The additional cohesion exercised by vegetation roots (cr) provides an important contribution to the slope stability. This study proposes a methodology for estimating the cr term in a hillslope landslide analysis within a coupled ecohydrological-stability model. The coupled model simulates the spatial distribution and temporal dynamics of the Factor of Safety (FS) as a function of soil moisture dynamics, by taking into account the hydrological effects of vegetation through the root water uptaking. The additional mechanical root cohesion is estimated in a Fiber Bundle Model framework that allows for the evaluation of the root strength as a function of stress-strain relationships of populatio…

Exploring the linkage between dew point temperature and precipitation extremes: A multi-time-scale analysis on a semi-arid Mediterranean region

Abstract Understanding warming climate implications on precipitation is of crucial importance, especially for areas particularly subjected to climate changes and land use/cover modifications, which could be extremely vulnerable to phenomena typically caused by rainfall extremes, such as floods and landslides. Past decade has been witnessing an increasing interest on simple modeling approaches based on the observation of commonly available meteorological variables and their physical linkages. In particular, based on the well-known thermodynamic Clausius-Clapeyron (CC) equation, it was widely investigated the scaling relation between rainfall extremes and variables representative of the near …

Evaluating several satellite precipitation estimates and global ground-based dataset on Sicily (Italy)

The developing of satellite-based precipitation retrieval systems, presents great potentialities for several ap­ plications ranging from weather and meteorological applications to hydrological modelling. Evaluating perfor­ mances for these estimates is essential in order to understand their real capabilities and suitability related to each application. In this study an evaluation analysis of satellite precipitation retrieval systems has been carried out for the area of Sicily (Italy). Sicily is an island in the Mediterranean sea with a particular climatology and morphology, which is considered as an interesting test site for satellite precipitation products on the European mid-latitude area…

Basin-scale water resources assessment in a sicilian basin under climate change scenarios using the conceptual model TOPDM

Climate change resulting due to the greenhouse effect is expected to have great implications for hydrological cycle and for existing surface and groundwater resources systems. The effects of climate variability and climate change have to be fully considered in current water management and planning, since water availability, quality and streamflow are very sensitive to changes in temperature and precipitation regimes. International literature proposes several models, attempting to assess accurately the available water resources under stationary and changing climatic conditions at different spatial and temporal scales. In order to assess the potential impacts of climate change on surface and …

MODELLAZIONE DELLA QUALITÀ DELLE ACQUE NEI RICETTORI IN TEMPO DI PIOGGIA

Hydrological regime modifications induced by climate change in Mediterranean area

The knowledge of river flow regimes has a capital importance for a variety of practical applications, in water resource management, including optimal and sustainable use. Hydrological regime is highly dependent on climatic factors, among which the most important is surely the precipitation, in terms of frequency, seasonal distribution and intensity of rainfall events. The streamflow frequency regime of river basins are often summarized by flow duration curves (FDCs), that offer a simple and comprehensive graphical view of the overall historical variability associated with streamflow, and characterize the ability of the basin to provide flows of various magnitudes. Climate change is likely t…

Tetti verdi multistrato per lo sviluppo sostenibile di città resilienti: quattro casi studio italiani

Negli ultimi anni le inondazioni in ambito urbano sono state sempre più frequenti, provocando notevoli danni sia livello sociale che a livello economico. Questo fenomeno è in parte determinato da un aumento di urbanizzazione causato dalla crescita della popolazione, che tende sempre più a spostarsi dalle zone rurali alle aree urbane, che si espandono molto velocemente, spesso con infrastrutture idrauliche inadeguate. Inoltre, a causa di cambiamenti climatici, soprattutto nelle aree mediterranee, si può osservare un aumento di lunghi periodi di siccità, intervallati da piogge di breve durata, ma di sempre più forte intensità e frequenza. La presenza di questi fenomeni di pioggia intensa, in …

Spatial distribution of rainfall trends in Sicily (1921–2000)

Abstract The feared global climate change could have important effects on various environmental variables including rainfall in many countries around the world. Changes in precipitation regime directly affect water resources management, agriculture, hydrology and ecosystems. For this reason it is important to investigate the changes in the spatial and temporal rainfall pattern in order to improve water management strategies. In this study a non-parametric statistical method (Mann–Kendall rank correlation method) is employed in order to verify the existence of trend in annual, seasonal and monthly rainfall and the distribution of the rainfall during the year. This test is applied to about 25…

TECNICA LS-PIV PER IL MONITORAGGIO DEI CORSI D’ACQUA NATURALI: UN APPROCCIO NUMERICO PER L’INDIVIDUAZIONE DI SETUP SPERIMENTALI OTTIMALI

Nuove tecniche per il monitoraggio ambientale, come le tecniche LS-PIV (Large-Scale Particle Image Velocimetry) e PTV (Particle Tracking Velocimetry), consentono una più speditiva e sicura acquisizione di misure di velocità nei corsi d’acqua. L’impiego di tecniche basate sull’elaborazione di immagini presenta infatti numerosi vantaggi che permettono di superare alcune criticità tipiche di approcci tradizionali (es. misure non invasive, low-cost, possibili anche in circostanze avverse e in real-time). Il recente sviluppo di tali tecniche è progredito di pari passo con la crescente disponibilità di sensori digitali sempre più performanti ed economici. Nonostante la grande disponibilità anche …

Reti Neurali per la Realizzazione di Mappe di Suscettibilità per il Rischio Frana

La valutazione della suscettibilità al dissesto rimane uno degli approcci più utilizzanti e più efficaci per l'analisi della pericolosità da frana. Come noto, la correlazione tra il fenomeno fisico ed i fattori predisponenti sulla base degli eventi accaduti in passato è il punto chiave di tale analisi. I metodi statistici, uniti con le tecnologie GIS, si sono rilevati in questi anni tra gli strumenti più idonei e più efficaci per la valutazione e la modellazione di tale correlazione. Tuttavia, questi metodi richiedono spesso ipotesi restrittive circa la distribuzione statistica dei dati che spesso non vengono rispettate. Per tale motivo si sono anche sviluppate metodologie alternative basat…

Time Series Analysis of Climatic Vegetation Data in the Oreto Watershed in Sicily

Analisi dei trend climatici in Sicilia

Salinity and periodic inundation controls on the soil-plant-atmosphere continuum of gray mangroves

Salinity and periodic inundation are both known to have a major role in shaping the ecohydrology of mangroves through their controls on water uptake, photosynthesis, stomatal conductance, gas-exchanges and nutrient availability. Salinity, in particular, can be considered one of the main abiotic regulating factors for halophytes and salt tolerant species, due to its influence on water use patterns and growth rate. Ecohydrological literature has rarely focused on the effects of salinity on plant transpiration, based on the fact that the terrestrial plants mostly thrive in low saline, unsaturated soils where the role of osmotic potential can be considered negligible. However, the effect of sal…

Regional models based on Multi-Gene Genetic Programming for the simulation of monthly runoff series

Accurate estimates of runoff in river basins are useful for several applications. The use of data-driven procedures for simulating the complex runoff generation process is a promising frontier that could allow for overcoming some typical problems related to more complex traditional approaches. This study explores soft computing based regional models for the reconstruction of monthly runoff in river basins. The region under analysis is the Sicily (Italy), where a regressive rainfall-runoff model, here used as benchmark model, was previously built using data from almost a hundred gauged watersheds across the region. This previous model predicts monthly river runoff based on a unique regional,…

A coupled eco-hydro-geomorphic investigation of basin response to climate change: Examining the role of climate on internal basin dynamics

Much attention has been devoted to assessing the relationship between changes in climate and landscape evolution. Given the complexity of dependence of geomorphic processes on hydrological and vegetation properties of the system, it is not surprising that different studies of fluvial response to climate change often appear contradictory, making difficult to generalize about how any given drainage basin will respond to changes in climate and/or land use. In this study, an integrated geomorphic component of the physically-based, spatially distributed hydrological model, tRIBS, the TIN-based Real-time Integrated Basin Simulator, is used to analyze the sensitivity of landscapes to climate chang…

Investigating the changes in extreme rainfall series recorded in an urbanised area

The aim of this study is to investigate and quantify changes in the rainfall regime of the metropolitan area of Palermo characterised by increasingly strong urbanisation. The rainfall data, considered in this study, were collected on a yearly basis from eight rain gauges within and outside the metropolitan area of Palermo, Sicily, Italy. A preliminary analysis made on the annual total rainfall depths showed a global reduction of total annual rainfall, with two different trends: more regular for the series observed in the rain gauges within the urbanised area and more variable for the series observed in the rain gauges outside the area. A further analysis has been performed using the series …

Modifications in Water Resources Availability Under Climate Changes: A Case Study in a Sicilian Basin

Climate variability due to the greenhouse effect has important implications on hydrological processes and water resources systems. Indeed, water availability, quality and streamflow are very sensitive to changes in temperature and precipitation regimes whose effects have to be fully considered in current water management and planning. International literature proposes several models, attempting to assess accurately the available water resources under stationary and changing climatic conditions at different spatial and temporal scales. In order to assess the potential impacts of climate change on surface and groundwater resources water availability in a Southern area of Italy, a conceptual h…

Influenza della soglia di accettazione nell’analisi di incertezza

Predicting reservoir water volumes in the Mediterranean area by combining a data-driven approach with seasonal forecasts data

Analisi dell'influenza della risoluzione del DEM e dell'area di soglia sulla risposta idrologica a scala di bacino

Assessment of climate impacts on hydrology and geomorphology of semiarid headwater basins using a physically-based model.

The response of watershed erosion rates to changes in climate is expected to be highly non-linear and thus demands for mechanistic approaches to improve our understanding of the underlying causes. In this study, the integrated geomorphic component tRIBS-Erosion of the physically-based, spatially distributed hydrological model, tRIBS, the TIN-based Real-time Integrated Basin Simulator, is used to analyze the sensitivity of small semi-arid headwater basins to projected climate conditions. Observed historic climate and downscaled realizations of general circulation models from CMIP3 inform the stochastic weather generator AWE-GEN (Advanced WEather GENerator), which is used to produce two clima…

Gestione delle emergenze da incendi boschivi: un sistema di supporto alle decisioni in ambiente GIS

Il presente studio è finalizzato alla definizione di un insieme di modelli decisionali e di procedure per la gestione a livello pre-operativo e operativo delle risorse antincendio boschivo disponibili nel territorio regionale siciliano. Per raggiungere tali obiettivi è stata messa a punto una struttura concettuale per la definizione di un sistema di supporto alle decisioni in grado di coadiuvare i responsabili della gestione delle emergenze alle diverse scale territoriali. La sintesi dello studio è costituita dall'implementazione di un prototipo relativo ad un modulo decisionale, atto a supportare le decisioni per la dislocalzione in tempo reale di uomini e mezzi, con riferimento ad un'area…

Implementing the erosion component of a physically based and distributed model (tRIBS). A first application to an experimental basin.

A coupled stability and eco-hydrological model to predict shallow landslides

Knowledge of spatio-temporal dynamics of soil water content, groundwater and infiltration processes is of considerable importance for the understanding and prediction of landslides. Rainfall and consequent water infiltration affect slope stability in various ways, mainly acting on the pore pressure distribution whose increase causes a decrease of the shearing resistance of the soil. For such reasons rainfall and transient changes in the hydrological systems are considered the most common triggers of landslides. So far, the difficulty to monitor groundwater levels or soil moisture contents in unstable terrain have made modeling of landslide a complex issue. At the present, the availability o…

TECNICHE OTTICHE PER IL MONITORAGGIO DEI CORSI D’ACQUA: UNA PROCEDURA AUTOMATICA PER L’INDIVIDUAZIONE DELLA MIGLORE SEQUENZA VIDEO DA PROCESSARE CON TECNICA LS-PIV

Misurare con accuratezza le portate di un corso d’acqua è uno dei principali obiettivi dell’idrometria tecnica (Eltner et al., 2020) e rappresenta da decenni una vera e propria sfida per la comunità scientifica. Le osservazioni di deflusso nei corsi d’acqua sono di fondamentale importanza per qualsiasi applicazione idrologica e idraulica (Pizarro et al., 2020) e consentono di comprendere al meglio le dinamiche di processi complessi, come ad esempio le piene lampo (Perks et al., 2016). La portata è una grandezza fisica la cui stima è caratterizzata da considerevole incertezza. Gli approcci tradizionali prevedono una stima indiretta della grandezza, attraverso un metodo velocità-area, che con…

The role of vegetation on gully erosion stabilization at a severely degraded landscape: A case study from Calhoun Experimental Critical Zone Observatory

Abstract Gully erosion was evidence of land degradation in the southern Piedmont, site of the Calhoun Critical Zone Observatory (CCZO), during the cotton farming era. Understanding of the underlying gully erosion processes is essential to develop gully erosion models that could be useful in assessing the effectiveness of remedial and soil erosion control measures such as gully backfilling, revegetation, and terracing. Development and validation of process-based gully erosion models is difficult because observations of the formation and progression of gullies are limited. In this study, analytic formulations of the two dominant gullying processes, namely, plunge pool erosion and slab failure…

Physically-based and distributed approach to analyze rainfall-triggered landslides at watershed scale

Abstract Landslides are a serious threat to life and property throughout the world. The causes of landslides are various since multiple dynamic processes are involved in driving slope failures. One of these causes is prolonged rainfall, which affects slope stability in different ways. Water infiltrating in a hillslope may cause a rise of the piezometric surface, which, in turn, involves an increase of the pore water pressure and a decrease of the soil shear resistance. For this reason, knowledge of spatio-temporal dynamics of soil water content, infiltration processes and groundwater dynamics, is of considerable importance in the understanding and prediction of landslides dynamics. In this …

Analyzing the role of soil water retention curve in slope stability for differently structured soils

 We analyzed the mechanical and hydrological effects of soil water retention curve (SWRC) models on the slope stability analyses of soils with unimodal and bimodal behavior.  We used three different SWRC models, two bimodal models (Ross&Smettem and Dexter) vs. the traditional van Genuchten model, to evaluate the Factor of Safety (FS) of a simple designed hillslope, based on the Bishop approach for unsaturated soils. Two formulations for term were also considered.  Results indicate that in cases of clayey soils, changes in FS obtained with different SWRC models especially at soil moisture values within the residual zone. In sandy soils the choice of formulations can be more important…

EHSM: UN NUOVO MODELLO CONCETTUALE PER LA SIMULAZIONE DEL DEFLUSSO GIORNALIERO

DEM-resolution control on rainfall-triggered landslide modeling within a triangulated network-based model

Catchment slope distribution significantly controls rainfall-triggered landslide modeling, in both direct and indirect ways. Slope directly determines the soil volume associated with instability. Indirectly, it affects the subsurface lateral redistribution of soil moisture across the basin, which in turn determines the water pore pressure conditions that impact slope stability. It is thus clear that the accuracy in reproducing slope distribution may be crucial in slope stability analysis. The resolution of the Digital Elevation Model (DEM) regulates the description of the topography. The correlation between raster resolution and landslide model outputs has been investigated in the literatur…

Evaluation and comparison of satellite precipitation estimates with reference to a local area in the Mediterranean Sea

Precipitation measurement is a key activity for the analysis of storm processes as well as every hydrological process. Satellite retrieval systems, rain-gauge network and radar systems are complement to each other in terms of their coverage and capability of monitoring precipitation. Satellite rainfall estimates systems produce data with global coverage that can provide information in areas for which data from other sources are unavailable. Without referring to ground measurement, satellite-based estimates can be bias. Although some gauged adjusted satellite precipitation products are developed, an effective way of integrating multi-sources of precipitation information is still a challenge.…

Regional frequency analysis of extreme rainfall in Sicily (Italy)

The effects of seasonal variability of precipitation and vegetation cycle on enhanced weathering for carbon sequestration

<p>Enhanced weathering (EW) is one of the most promising technologies for sequestering atmospheric carbon. It consists on accelerating the chemical weathering fluxes naturally occurring in soils, by means of the addition of silicate minerals (i.e., <em>forsterite</em>), used as amendments, to the soil. If crushed into micrometer-sized particles, these minerals are characterized by high dissolution rates, that may be further improved under high soil water content and low pH conditions. Before actually applying EW technique at the global scale for carbon sequestration, an in-depth characterization of weathering and carbon sequestration rates, under di…

Using a physically-based model, tRIBS-Erosion, for investigating the effects of climate change in semi-arid headwater basins.

Soil erosion due to rainfall detachment and flow entrainment of soil particles is a physical process responsible for a continuous evolution of landscapes. The rate and spatial distribution of this phenomenon depend on several factors such as climate, hydrologic regime, geomorphic characteristics, and vegetation of a basin. Many studies have demonstrated that climate-erosion linkage in particular influences basin sediment yield and landscape morphology. Although soil erosion rates are expected to change in response to climate, these changes can be highly non-linear and thus require mechanistic understanding of underlying causes. In this study, an integrated geomorphic component of the physic…

Analisi comparativa di modelli euristici e statistici spaziali nella derivazione della suscettibilità da colate rapide di fango e detrito.

La suscettibilità da frana può essere definita come la propensione di una determinata area all’innesco di movimenti di massa, in relazione alle caratteristiche intrinseche dei terreni di copertura e del substrato, delle caratteristiche morfologiche ed alla maggiore esposizione nei confronti degli agenti climatici. Nel corso degli anni sono stati sviluppati vari metodi per valutare la suscettibilità, basati su approcci sia di tipo deterministico che statistico. Tutti i metodi si basano su poche assunzioni fondamentali secondo cui la franosità è controllata da leggi meccaniche che possono essere determinate in modo empirico, statistico o deterministico. Scopo del presente lavoro è quello di v…

Utilizzo degli L-Moments per l’analisi regionale delle portate di piena in Sicilia.

Annual runoff assessment in arid Mediterranean watersheds under the Budyko framework

The solution of many practical water problems is strictly connected to the availability of reliable and widespread information about runoff. The estimation of mean annual runoff and its interannual variability for any basin over a wide region, even if ungauged, would be fundamental for both water resources assessment and planning and for water quality analysis. Starting from these premises, the main aim of this work is to show how using the Budyko framework is possible to map the mean annual surface runoff and derive the pdf of the same variable in arid watersheds. As a case study, the entire island of Sicily, Italy, is here proposed. First, time series data of annual rainfall, runoff and r…

Assessment of the technical and economic potential of offshore wind energy via a GIS application: A case study for the Sicily Region according to Italian laws and incentive frameworks

This paper presents a technical and economic analysis of the possible exploitation of offshore wind resources using spatial analysis methods based on GIS tools. The study assessed the magnitude and distribution of the main constraints on installation of wind farms by taking into account the relevant technical factors and local laws on nature protection issues in a specific area, i.e., Sicily. Specific cost functions were defined for several components of the total cost of construction and maintenance of a wind farm. Several scenarios were implemented according to wind turbine size, hub height, total wind farm power, and distance from the coast, and the levelised production cost was assessed…

Large-Eddy Simulation in LSPIV techniques: the study of surface turbolence

<p>In recent years, technological advances have been observed in environmental monitoring field, leading to a rapid spread of innovative technologies overcoming many historical challenges. In river monitoring field the use of image-based techniques provides non-intrusive measurements ensuring the best safety conditions for operators. The most used optical methods are the Large-Scale Particle Image Velocimetry (LSPIV) and the Large-Scale Particle Tracking Velocimetry (LSPTV).</p><p>In LSPIV and LSPTV techniques a floating tracer is introduced on the water surface and its motion is recorded by commercial devices (e.g. digital cameras). Resulting video…

Mapping the annual runoff data in Sicily using a geostatistical approach

The availability of reliable and long time series of runoff data is fundamental for most of the hydrological analyses and for the assessment and the management of water resources even in condition of global climatic change. However, hydrologic data set are often characterized by a short duration and also suffer from missing data values, mainly due to malfunctioning of gauging stations for a specific period. In order to overcome this problem and obtain long and continuous runoff time series, different models and methods have been previously developed and proposed. While some models, used to extent the streamflow record, are conceptual, empirical, regressive models based on the rainfall input…

Use of L-moments approach for regional flood frequency analysis in Sicily, Italy

Extremely great floods are among environmental events with the most disastrous consequences for the entire world. Estimates of their return periods and design values are of great importance in hydrologic modeling, engineering practice for water resources and reservoirs design and management, planning for weather-related emergencies, etc. Regional flood frequency analysis resolves the problem of estimating the extreme flood events for catchments having short data records or ungauged catchments. This paper analyzes annual maximum peak flood discharge data recorded from more than 50 stream flow gauging sites in Sicily, Italy, in order to derive regional flood frequency curves. First these data…

tRIBS-Erosion: combining mechanistic approaches for investigating eco-hydro-geomorphic response of river basins to climate change

Vegetation interacts with hydrology, geomorphology and processes of a river basin in profound ways. Despite recent advances in hydrological modeling, the dynamic coupling between these processes is yet to be adequately captured at the basin scale to elucidate key features of process interaction and their role in the organization of vegetation and landscape morphology. In this study, a newly integrated geomorphic component of the physically-based, spatially distributed hydrological model, tRIBS, the TIN-based Real-time Integrated Basin Simulator, is presented. Hillslope and channel erosion processes are parsimoniously coupled with vegetation-hydrology dynamics, making it possible to study ho…

Regional flow duration curves for ungauged sites in Sicily

Abstract. Flow duration curves are simple and powerful tools to deal with many hydrological and environmental problems related to water quality assessment, water-use assessment and water allocation. Unfortunately the scarcity of streamflow data enables the use of these instruments only for gauged basins. A regional model is developed here for estimating flow duration curves at ungauged basins in Sicily, Italy. Due to the complex ephemeral behaviour of the examined region, this study distinguishes dry periods, when flows are zero, from wet periods using a three parameters power law to describe the frequency distribution of flows. A large dataset of streamflows has been analysed and the param…

The impact of climate change on extreme precipitation in Sicily, Italy

Increasing precipitation extremes are one of the possible consequences of a warmer climate. These may exceed the capacity of urban drainage systems, and thus impact the urban environment. Because short-duration precipitation events are primarily responsible for flooding in urban systems, it is important to assess the response of extreme precipitation at hourly (or sub-hourly) scales to a warming climate. This study aims to evaluate the projected changes in extreme rainfall events across the region of Sicily (Italy) and, for two urban areas, to assess possible changes in Depth-Duration-Frequency (DDF) curves. We used Regional Climate Model outputs from Coordinated Regional Climate Downscalin…

Derivation of Rainfall Thresholds for Flash Flood Warning in a Sicilian Basin Using a Hydrological Model

Abstract The damages caused by flash floods are among the most onerous in terms of loss of lives and damage to properties. Derivation of rainfall threshold is one of the approaches commonly used for the development of flash flood warning systems. Specifically, rainfall threshold is the rainfall amount that, for a given basin area and duration, is enough to cause flooding and, therefore, it indicates the maximal sustainable rainfall for a basin. The aim of this paper is deriving flash flood-rainfall thresholds for a Sicilian basin (Italy) throughout a deterministic approach. The conceptual hydrological model TOPDM was used to estimate the amount of rainfall that, for given duration, hydrolog…

ModABa MODEL: ANNUAL FLOW DURATION CURVES ASSESSMENT IN EPHEMERAL BASINS

A representation of the streamflow regime for a river basin is required for a variety of hydrological analyses and engineering applications, from the water resource allocation and utilization to the environmental flow management. The flow duration curve (FDC)represents a comprehensive signature of temporal runoff variability often used to synthesize catchment rainfall-runoff responses. Several models aimed to the theoretical reconstruction of the FDC have been recently developed under different approaches, and a relevant scientific knowledge specific to this topic has been already acquired. In this work, a new model for the probabilistic characterization of the daily streamflows in perennia…

Integrazione di tecniche GIS e dati telerilevati per il bilancio idrologico del suolo

Utilizzo di modelli lineari generalizzati nella derivazione di mappe di suscettibilità per il rischio idrogeologico

L’analisi statistica basata sulla correlazione tra cause e occorrenze, costituisce uno degli approcci più utilizzati in letteratura scientifica per la valutazione delle aree propense a produrre dissesti idrogeologici. Tra questi, il dissesto da frana rappresenta uno tra i più pericolosi e dannosi eventi naturali che negli ultimi anni hanno particolarmente colpito tutto il territorio nazionale. Il presente lavoro si pone come obiettivo quello di valutare l’efficienza di un modello statistico multivariato per la determinazione di mappe di suscettibilità al rischio idrogeologico, basandosi sulla correlazione tra fattori innescanti e occorrenze. Tra i modelli statistici presenti in letteratura …

The role of hydrological processes on enhanced weathering for carbon sequestration in soils in tropical areas

<p>To mitigate global warming, a noticeable research effort is being devoted to NCS (Natural Climate Solutions) as means to reduce greenhouse gas emissions or sequester carbon within the oceans or terrestrial environments by exploiting natural processes. Enhanced weathering<strong> </strong>is a NCS that aims to increase the weathering reaction rates of silicate minerals, by amending soils with crushed reactive minerals. Various studies have shown that this technique is favored by hot and humid climates (i.e., tropical ecosystems), since weathering reactions are mostly effective under high temperature and soil moisture. Despite olivine dissolution d…

Comparative Analysis of Spatial Interpolation Methods in the Mediterranean Area: Application to Temperature in Sicily

An exhaustive comparison among different spatial interpolation algorithms was carried out in order to derive annual and monthly air temperature maps for Sicily (Italy). Deterministic, data-driven and geostatistics algorithms were used, in some cases adding the elevation information and other physiographic variables to improve the performance of interpolation techniques and the reconstruction of the air temperature field. The dataset is given by air temperature data coming from 84 stations spread around the island of Sicily. The interpolation algorithms were optimized by using a subset of the available dataset, while the remaining subset was used to validate the results in terms of the accur…

Monthly Hydrological Indicators to Assess Possible Alterations on Rivers’ Flow Regime

Assessing potential deviations of the fundamental river basins’ hydrological processes and streamflow characteristics from the “natural trajectory” represents a high-priority objective to understand the biological impact of altered flow regime on river ecosystems. Existing approaches are mainly based on the analysis of daily-based indicators of hydrologic alteration, which requires wide database, including “pre-impact” and “post-impact” daily flow data frequently unavailable. The hydrological modeling is commonly used to face data missing problems or reconstruct natural conditions, even if models, especially at the daily scales, are often complex and computationally intensive. The use of si…

tRIBS-Erosion: A parsimonious physically-based model for studying catchment hydro-geomorphic response

Our goal is to develop a model capable to discern the response of a watershed to different erosion mechanisms. We propose a framework that integrates a geomorphic component into the physically-based and spatially distributed TIN-based Real-time Integrated Basin Simulator (tRIBS) model. The coupled model simulates main erosive processes of hillslopes (raindrop impact detachment, overland flow entrainment, and diffusive processes) and channel (erosion and deposition due to the action of water flow). In addition to the spatially distributed, dynamic hydrologic variables, the model computes the sediment transport discharge and changes in elevation, which feedback to hydrological dynamics throug…

Influence of spatial precipitation sampling on hydrological response at catchment scale

Retrieving precipitation data from raingauge network is a classical and common practice in hydrology and climatology. These data represent the key input in hydrological modeling to reproduce, for example, the characteristics of a flood phenomenon. The accuracy of the model results is strongly dependent on the consistency of the monitoring network in terms of spatial scale, i.e. network density and location of raingauges, and time resolution. In this context, several studies have been carried out to analyze how the rainfall sampling influences the estimation of total runoff volume. The aim of this paper is to use a physically based and distributed-parameter hydrologic model to investigate ho…

Effects of initialization conditions in distributed hydrological response: spatio-temporal dependencies on rainfall forcing, watershed topography and soils

Trend analysis of convective and stratiform precipitation over a Mediterranean area

Separating convective and stratiform rainfall is still today an open challenge, especially because of the difficulty in defining a clear distinction between the two rainfall regimes. At the same time, the study of convective rainfall is essential to better understand the dynamics that generate them and the proactive measures that could reduce the risk of important consequences (e.g., human life losses and economic damages). Furthermore, the shadow of a changing climate makes these aspects even more alarming, due to the possibility of an increase in the occurrence of such severe events. Sicily, whose climate could be considered as representative of the central Mediterranean area, has been of…

Integration of physically based distributed hydrological model with model of carbon and nitrogen cycle: Luquillo Critical Zone Observatory, Puerto Rico

The dynamics of carbon and nitrogen cycles, increasingly influenced by human activities, are the key to the functioning of ecosystems. These cycles are influenced by the composition of the substrate, availability of nitrogen, the population of microorganisms, and by environmental factors. Therefore, land management and use, climate change, and nitrogen deposition patterns influence the dynamics of these macronutrients at the landscape scale. In this work a physically based distributed hydrological model, the tRIBS model, is coupled with a process-based multi-compartment model of the biogeochemical cycle to simulate the dynamics of carbon and nitrogen (CN) in the Mameyes River basin, Puerto …

INVESTIGATING RESERVOIR SEDIMENT AND CATCHMENT EROSION USING THE WEPP MODEL

Accounting for soil parameter uncertainty in a physically based and distributed approach for rainfall-triggered landslides

In this study we propose a probabilistic approach for coupled distributed hydrological-hillslope stability models that accounts for soil parameters uncertainty at basin scale. The geotechnical and soil retention curve parameters are treated as random variables across the basin and theoretical probability distributions of the Factor of Safety (FS) are estimated. The derived distributions are used to obtain the spatio-temporal dynamics of probability of failure, in terms of parameters uncertainty, conditioned to soil moisture dynamics. The framework has been implemented in the tRIBS-VEGGIE (Triangulated Irregular Network (TIN)-based Real-time Integrated Basin Simulator-VEGetation Generator fo…

Parametric uncertainty or hydrological changes?

Abstract. The model calibration is the way of hydrologists for searching also a physical interpretation of complex interactions acting within a basin. Actually, it can be frequently noticed how model calibration performed on a given time-window may converge to a point in the parameter space that could be distant from another obtainable calibration of the model in the same basin but considering a different time window. Is that again parametric uncertainty or does the trajectory in the parametric space relate about to a slow hydrological basin change? This paper depicts a possible path for detecting changes' signatures in a streamflow time series. In particular, the paper seeks to draw a way …

Regional frequency analysis of extreme precipitation in Sicily, Italy

The role of urban growth, climate change, and their interplay in altering runoff extremes

Changes in climate and urban growth are the most influential factors affecting hydrological characteristics in urban and extra-urban contexts. The assessment of the impacts of these changes on the extreme rainfall–runoff events may have important implications on urban and extra-urban management policies against severe events, such as floods, and on the design of hydraulic infrastructures. Understanding the effects of the interaction between climate change and urban growth on the generation of runoff extremes is the main aim of this paper. We carried out a synthetic experiment on a river catchment of 64 km2to generate hourly runoff time series under different hypothetical scenarios. We impos…

Effetti di urbanizzazione e cambiamenti climatici sui deflussi a scala di bacino

Fra le pressioni di natura antropica agenti sui bacini idrografici, particolare rilevanza hanno sia la progressiva perdita di suoli naturali in favore di suoli poco, o per nulla, permeabili (es. strade, edifici, parcheggi, etc.) che la regimazione e regolazione dei deflussi sulla rete di drenaggio naturale mediante interventi idraulici. In particolare, l’ultima relazione sullo stato dell’ambiente europeo a cura dell’Agenzia Europea dell’Ambiente (AEA, 2010) considera l’impermeabilizzazione dei bacini naturali come uno dei maggiori processi di degrado del suolo. L’aumento del grado di urbanizzazione dei bacini naturali, inteso come aumento della frazione impermeabile del suolo derivante dell…

Modeling the hydrological and mechanical effect of roots on shallow landslides

This study proposes a new methodology for estimating the additional shear strength (or cohesion) exerted by vegetation roots on slope stability analysis within a coupled hydrological-stability model. The mechanical root cohesion is estimated within a Fiber Bundle Model framework that allows for the evaluation of the root strength as a function of stress-strain relationships of populations of fibers. The use of such model requires the knowledge of the root architecture. A branching topology model based on Leonardo's rule is developed, providing an estimation of the amount of roots and the distribution of diameters with depth. The proposed methodology has been implemented into an existing dis…

Derivation of a Distributed Unit Hydrograph Integrating GIS and Remote Sensing

The paper describes the results of a study based on the integration of remote sensing and geographical information system techniques to evaluate a distributed unit hydrograph model linked to an excess rainfall model for estimating the streamflow response at the outlet of a watershed. Travel time computation, based on the definition of a distributed unit hydrograph, has been performed, implementing a procedure using (1) a cell-to-cell flow path through the landscape determined from a digital elevation model (DEM); and (2) roughness parameters obtained from remote sensing data. This procedure allows the taking into account of the differences, in terms of velocity, between the hillslopes and t…

Regional frequency analysis of extreme precipitation for Sicily (Italy)

The analysis of extreme precipitation has always been included among most relevant hydrological applications because of the several important activities linked to the availability of tools for the estimation of extreme rainfall quantiles. These activities include the design of hydraulic civil structures and the evaluation and management of hydraulic and hydrological risk. In this study a frequency analysis of annual maxima precipitation measurements has been carried out for the area of Sicily (Italy). A typical hierarchical regional approach has been adopted for the parameter estimation procedure based on the L-moments method. The identification of homogeneous regions within the procedure h…

Wind speed and temperature trends impacts on reference evapotranspiration in Southern Italy

In this study, the impacts of both temperature and wind speed trends on reference evapotranspiration have been assessed using as a case study the Southern Italy, which present a wide variety of combination of such climatic variables trends in terms of direction and magnitude. The existence of statistically significant trends in wind speed and temperature from observational datasets, measured in ten stations over Southern Italy during the period 1968–2004, has been investigated. Time series have been examined using the Mann–Kendall nonparametric statistical test in order to detect possible evidences of wind speed and temperature trends at different temporal resolution and significance level.…

EFFECTS OF DATA GAP ON THE CAPABILITY TO DETECT TREND IN HYDROCLIMATOLOGICAL TIME SERIES

In the last decades the growing concerns about the existence of global climatic changes push many researchers to use different trend test in order to identify whether monotonic trends exist in hydroclimatological time series such as temperature, precipitation, and streamflow. Unfortunately, these time series often suffer from missing data values mainly due to malfunctioning of gauge for specific time periods. Starting from this premise, the main target of our work is to investigate the effect of data gap in a time series on the results provided by the most used trend test: the nonparametric Mann–Kendall statistical test. Firstly, different synthetic time series characterized by different si…

Physically based modeling of rainfall-triggered landslides: a case study in the Luquillo forest, Puerto Rico

This paper presents the development of a rainfall-triggered landslide module within an existing physically based spatially distributed ecohydrologic model. The model, tRIBS-VEGGIE (Triangulated Irregular Networks-based Real-time Integrated Basin Simulator and Vegetation Generator for Interactive Evolution), is capable of a sophisticated description of many hydrological processes; in particular, the soil moisture dynamics are resolved at a temporal and spatial resolution required to examine the triggering mechanisms of rainfall-induced landslides. The validity of the tRIBS-VEGGIE model to a tropical environment is shown with an evaluation of its performance against direct observations made w…

An integrated information system for the acquisition, management and sharing of environmental data aimed to decision making

This paper reports the first results of the Project SESAMO - SistEma informativo integrato per l’acquisizione, geStione e condivisione di dati AMbientali per il supportO alle decisioni (Integrated Information System for the acquisition, management and sharing of environmental data aimed to decision making). The main aim of the project is to design and develop an integrated environmental information platform able to provide monitoring services for decision support, integrating data from different environmental monitoring systems (including WSN). This ICT platform, based on a service-oriented architecture (SOA), will be developed to coordinate a wide variety of data acquisition systems, based…

Integration between quality models and GIS to assess water bodies quality conditions. An application to the Platani river

Evaluation and comparison of satellite precipitation estimates with reference to a local area

Precipitation is one major variable for many applications. Satellite retrieval systems, raingauge network and radar systems are complement to each other in terms of their coverage and capability of monitoring precipitation. Satellite rainfall estimates systems produce data with global coverage that can provide information in areas for which data from other sources are unavailable.Without referring to ground measurement, satellite-based estimates can be bias. Although some gauged adjusted satellite precipitation products are developed, an effective way of integrating multi-sources of precipitation information is still a challenge. In this study we select a specific area in Sicily (Italy) hav…

A paradigm of extreme rainfall pluvial floods in complex urban areas: the flood event of 15 July 2020 in Palermo (Italy)

Abstract. In the last few years, some regions of the Mediterranean area have witnessed a progressive increase in extreme events, such as urban and flash floods, as a response to the increasingly frequent and severe extreme rainfall events, which are often exacerbated by the ever-growing urbanization. In such a context, the urban drainage systems may not be sufficient to convey the rainwater, thus increasing the risk deriving from the occurrence of such events. This study focuses on a particularly intense urban flood that occurred in Palermo (Italy) on 15 July 2020; it represents a typical pluvial flood due to extreme rainfall on a complex urban area that many cities have experienced in rece…

USING HIGH RESOLUTION RAINGAUGE DATA FOR STORM TRACKING ANALYSIS IN THE URBAN AREA OF PALERMO, ITALY

This paper presents a comparative analysis between rain-gauge storm tracking techniques in order to achieve a better knowledge of the rainfall dynamics over an urbanized area. The temporal and spatial distribution and kinematics of short term rainfall are recognized as one of the most important reasons in error production in rainfall-runoff on urban catchments. The uncertainty due to rainfall variability can greatly affect urban drainage modeling performance and reliability thus reducing the confidence of operators in their results. Modeling representations of urban catchments and drainage systems are commonly adopted for surface flooding forecasting and management and an adequate knowledge…

MODELING THE SHRUB ENCROACHMENT IN THE NORTHERN CHIHUAHUAN DESERT GRASSLANDS WITH A CELLULAR AUTOMATA MODEL

A physically-based and distributed tool for modeling the hydrological and mechanical processes of shallow landslides

This work presents the capabilities of a model, i.e. the tRIBS-VEGGIE-Landslide, in two different versions, i.e. developed within a probabilistic framework and coupled with a root cohesion module. The probabilistic model treats geotechnical and soil retention curve parameters as random variables across the basin and estimates theoretical probability distributions of slope stability and the associated “factor of safety” commonly used to describe the occurrence of shallow landslides. The derived distributions are used to obtain the spatiotemporal dynamics of probability of failure, conditioned on soil moisture dynamics at each watershed location. The framework has been tested in the Luquillo …

Modeling belowground water table fluctuations in the Everglades

Humid lands, such as riparian zones, peatlands, and unsubmerged wetlands, are considered among the most biologically diverse of all ecosystems, providing a bountiful habitat for a large number of plant and animal species. In such ecosystems, the water table dynamics play a key role in major ecohydrological processes. The aim of the present study is to test with field data a recent analytical model for the estimation of the long‐term probability distribution of the belowground water table position in groundwater‐dependent environments. This model accounts for stochastic rainfall and processes such as infiltration, root water uptake, water flow from/to an external water body, and capillary fl…

The role of hydrology on enhanced weathering for carbon sequestration I. Modeling rock-dissolution reactions coupled to plant, soil moisture, and carbon dynamics

Abstract Enhanced Weathering (EW) resulting from soil amendment with highly reactive silicate minerals is regarded as one of the most effective techniques for carbon sequestration. While in laboratory conditions silicate minerals dissolution rates are well characterized, in field conditions the rate of the dissolution reaction is more difficult to predict, not least because it interacts with soil, plant, and hydrologic processes. Here we present a dynamic mass balance model connecting biogeochemical and ecohydrological dynamics to shed light on these intertwined processes involved in EW. We focus on the silicate mineral olivine, for its faster laboratory dissolution rate, and pay particular…

Daily rainfall statistics in Sicily (1920-2000)

Rainfall characteristics are crucial for vegetation patterns formation and evolution in Mediterranean ecosystems. Changes in rainfall frequency and intensity could cause vegetation water stress for some plant species and benefit, at the same time, other species, driving coexistence and competition dynamics. The changes in the precipitation characteristics are sometimes more important than the changes in the total amount of precipitation in determining the partitioning between green and blue water with several implications for both the vegetation communities health and water resource management. Decreasing rainfall is a clear signature of climate change in Mediterranean countries. Annual and…

Predicting the impacts of climate change on plant dynamics and tree-grass-shrub competition using a Cellular Automata model in a Mediterranean catchment in Sicily, Italy

INFLUENCE OF RAINFALL OBSERVATION NETWORK ON MODELED HYDROLOGICAL RESPONSE

Precipitation data, one of the most important input required in hydrological modeling and forecasting, are usually recorded using raingauges which are classical and fundamental tools able to provide an estimate of rainfall at a point. The consistency of precipitation monitoring network in terms of spatial scale (network density and location of raingauges) and time resolution has to be capable to reproduce, with acceptable accuracy, the characteristics of the flood phenomenon. In this context, over the last thirty years, several studies concerning the influence of point measurement of rainfall for the estimation of total runoff volume have been carried out. Aim of this paper is using a physi…

Combining Mechanistic Approaches for Studying Eco-Hydro-Geomorphic Coupling

Time series analysis of climate and vegetation variables in the Oreto watershed (Sicily, Italy)

Effects of Digital Elevation Model resolution on evaluation of landslide susceptibility with a logistic regression model.

The use of statistical methods together with the GIS technologies is currently one of the most efficient tools in the assessment of landslide susceptibility. The correlation between the physical phenomenon and its triggering factors depends on several factors, including the resolution at which the elevation data are represented in a Digital Elevation Model (DEM). The resolution becomes increasingly important as the use of DEM data is extended for spatial prediction of terrain attributes such as slope, aspect, plan and profile curvature, etc., which are considered as triggering factors of the landslides. Many methods exist in scientific literature to capture and model the correlation between…

Procedure di caratterizzazione dei dati storici

Climate changes effects on vegetation in Mediterranean areas

The Mediterranean ecosystems evolved under climatic conditions characterized by precipitations markedly out of phase with the growing period for the vegetation there established. In such environments, deep and shallow rooted species cohabit and compete each other. The formers, being characterized by deeper root, are able to utilize the water stored during the dormant season, while the conditions of shallow rooted plant are closely related to the intermittence of the precipitations. A numerical model has been here used in order to carry out an analysis of the potential climate changes influence on the vegetation state in a typical Mediterranean environment, such as Sicilian one. The most imp…