Cassiraga Eduardo

• Professor
• Professor (Associate) at Polytechnic University of Valencia

In times of population growth, climate change, and increasing water scarcity around the world, it is important to take an objective look at water, a fundamental resource for life. Hydrodynamic modeling makes possible the research of different aspects of the water cycle and the evaluation of different hydrological and hydrogeological forecasting sce...

Aquifers are ubiquitous, and their water is easy to obtain with low extraction costs. On many occasions, these characteristics lead to overexploitation due to important water level declines, reduction of river base flows, enhanced seawater intrusion, and wetland affection. The forecasted increase in water demands and global warming will impact the...

Predicting pesticides' behavior in the environment is necessary to anticipate and minimize their adverse effects. Despite the use of pesticides in Spain is increasing, the implementation and use of predictive mathematical models is seldomly done in practice due to the lack of available data. In this original work, the Pesticide Root Zone Model vers...

Pétrola Lake in southeast Spain is one of the most representative examples of hypersaline wetlands in southern Europe. The rich ecosystem and environmental importance of this lake are closely associated with the hydrogeological behaviour of the system. The wetland is fed by the underlying aquifer with relatively fresh groundwater—1 g L−1 of total d...

Chlorpyrifos, Bromacil and Terbuthylazine are commonly used as insecticides and herbi-cides to control weeds and prevent non-desirable growth of algae, fungi and bacteria in many agricultural applications. Despite their highly negative effects on human health, environmental model-ing of these pesticides in the vadose zone until they reach groundwat...

The objective of this study was to analyse periodicities and the long-term variability of monthly Júcar River–Mancha Oriental Aquifer interactions (RAI) and regionally measured precipitation (PP) with special focus on the correlations between these local hydrological variables and the large climatic patterns governing the Iberian Peninsula, represe...

Automatic interpolation of precipitation maps combining rain gauge and radar data has been done in the past but considering only the data collected at a given time interval. Since radar and rain gauge data are collected at short intervals, a natural extension of previous works is to account for temporal correlations and to include time into the int...

The use of Strategic Environmental Assessment (SEA) systems is essential to ensure the sustainability of plans, programs and policies. This works shows, for the first time in the scientific literature, a joint vision of the current situation of SEA systems in Costa Rica, El Salvador, Guatemala, Panama and the Dominican Republic. The analysis has be...

Terbuthylazine is commonly used as an herbicide to control weeds and prevent non-desirable grow of algae, fungi and bacteria in many agricultural applications. Despite its highly negative effects on human health, environmental modeling of this kind of pesticide in the vadose zone till reaching groundwater is still not being done on a regular basis....

Predicting the fate of pesticides released into the natural environment is necessary to anticipate and minimize adverse effects far from the contamination source. These effects arise due to the movement of pesticides in surface water and can take place via drift, surface runoff and subsurface flow. A number of models have been developed to predict...

This paper introduces BIOLEACH, a new decision support model for the real-time management of municipal solid waste bioreactor landfills that allows estimating the leachate and biogas production. Leachate production is estimated using an adaptation of the water balance equation which considers every hydrological component and the water consumed by a...

This study presents an analysis of three models associated with artificial intelligence as tools to forecast the generation of urban solid waste in the city of Bogot�a, in order to learn about this type of waste's behavior. The analysis was carried out in such a manner that different efficient alternatives are presented. In this paper, a possible dec...

Groundwater flow models have been increasingly used to support policy making. A substantial amount of research has been dedicated to improving, validating and calibrating models and including stakeholders in the modelling process. However, little research has been done to analyze how the choices of model makers and steering by policy makers result...

Pesticide application has currently been identified as one of the most relevant soil contamination sources on agricultural areas. Understanding the fate and transport of pesticides in the vadose zone is critical to predict the impact assessment of agricultural activities over the soil. This work show the application of two different USEPA numerical...

Abstracts from Valencia GEOSTATS2016 Vol. 1

The eigenvalue method with selective compression and modal masking (EVM-SCMM) allows to develop criteria to generate effectivemodes efficiently, to remove residual modes and to build the modal mask that accelerates the simulations. Based on the above, algorithms to generate effective modes and to configure modal masks are proposed. These algorithms...

The eigenvalue method (EVM) has proved to be an efficient method for the aquifer’s simulation in conjunctive use systems. It solves the spatially discretized PDE of groundwater flow using very simple, explicit and continuous in time state equations through their modal orthogonal components. A new improved methodology, called eigenvalue method with...

An extension of the Rational Lanczos reduction method (RLANRM) to simulate efficiently surface-ground water interactions in models of conjunctive use systems is proposed. The RLANRM is used to form an orthogonal base of a Krylov’s reduction subspace. As a criterion to stop the generation of the reduction’s subspace, accumulated volumetric allocatio...

The eigenvalue method with selective compression and modal masking (EVM-SCMM) and the rational Lanczos reduction method (RLANRM) have been applied to reduce groundwater models of two complex and highly discretized linear heterogeneous aquifers. The former is a rectangular aquifer with three bands with homogenous hydraulic properties, which is conne...

Nitrate concentrations in multi-aquifer systems are heavily affected by the presence of wellbores (active or abandoned) that are screened in several aquifers. The spatial variability of hydraulic conductivity in the confining layers has also an important impact on the concentrations. A synthetic three-dimensional flow and transport exercise was car...

The Mancha Oriental System (MOS, 7,260km(2)) is one of the largest aquifers within Spain, and is encompassed by the Jucar River Basin. Over the past 30years, socioeconomic development within the region has been largely due to intensive use of groundwater resources for irrigating crops (1,000km(2)). Groundwater pumping (406 million m(3)/year) has pr...

This paper evaluates the performance of spatial methods to estimate leaf area index (LAI) fields from ground-based measurements at high-spatial resolution over a cropland landscape. Three geostatistical model variants of the kriging technique, the ordinary kriging (OK), the collocated cokriging (CKC) and kriging with an external drift (KED) are use...

Quantitative estimation of rainfall fields has been a crucial objective from early studies of the hydrological applications of weather radar. Previous studies have suggested that flow estimations are improved when radar and rain gauge data are combined to estimate input rainfall fields. This paper reports new research carried out in this field. Cla...

We present a methodology to estimate the uncertainty associated with the determination of contaminated areas requisite for the assessment and application of soil remediation techniques. This methodology uses geostatistical techniques to develop uncertainty models of contaminant concentrations. The advantage of this method is that it accounts for th...

Stochastic simulations of solute transport in heterogeneous log10 K random fields were conducted at two different support scales to assess solute transport upscaling methods in the context of nuclear waste disposal. A very fine grid-scale is used to obtain a reference solution of the real problem, which is based on data from the Sellafield site. A...

The scale of measurements is typically orders of magnitude smaller than the computational scale requisite for achieving a functional model. Upscaling is the process by which information at a given small support scale (e.g. core samples) is transferred to a larger support scale given by the numerical model grid-blocks. At the present, upscaling tech...

The disparity of scales between measurements and models requires a decision on how to extrapolate information collected at a given scale (generally small) onto the scale at which performance assessment is evaluated (generally orders of magnitude larger than the measurement scale). This problem only applies for those parameters with a considerable d...

Development of improved methodologies to estimate rainfall fields merging radar and raingauges data has been an objective from the initial studies of hydrological applications of meteorological radar. Some previous works have reported that rainfall fields estimated using cokriging technique to merge radar and raingauges measurements improve flood e...

The use of radar data is a powerful tool to improve rainfall spatio-temporal estimation. Geostatistical techniques are well suited to combine both raingage and radar measurements for this purpose. The main problem of this application, particularly in the context of real time estimation, is the definition of a positive definite model of cross-correl...

La simulación del flujo y transporte en rocas fracturadas puede ser aproximada por medio de modelos de fracturas discretas. Estos modelos son difíciles de calibrar debido a la escasez en el conocimiento de la localización y geometría de las fracturas, y la distribución 2D de los parámetros hidrodinámicos dentro de ellas, una aproximación alternativ...

La modelización del flujo y transporte en una formación rocosa fracturada requiere realizar en muchas ocasiones una representación explícita de las fracturas. En estos casos los modelos de fracturas discretas no son siempre apropiados debido a las dificultades en su calibración y a sus dificultades en representar con suficiente precisión el número...

Entre junio de 2000 y febrero de 2001, se condujo un experimento de difusión en la zona de fractura de la arcilla Opalinus en el túnel de Mt. Terri (Suiza). Se utilizaron como trazadores 4He, 3He, tritio e ioduro. Se condujeron los siguiente experimentos: difusión hacia la perforación desde la formación de 4He, difusión desde la perforación a la fo...

The pressure variations observed during an interference test performed in a fractured volcanic tuff are modeled using a stochastic continuum approach. Two sets of spatially heterogeneous conductivity fields are generated. The first one is only conditioned to hard and soft data on conductivities, whereas the second one is also conditioned to transie...

Probability field simulation appears as a powerful technique for fast generation of conditional realizations of correlated random fields. However, its theoretical foundation has been established only for the unconditional case: the only case for which probability fields have no advantage. The aim of this presentation is to investigate the possibili...

Rainfall areal estimation is a common problem that appears in many fields such as meteorology, hydrology or agronomy. Rainfall is an intermittent phenomenon in both space and time and it displays large spatio- temporal variability. Raingage networks collect point estimates of rainfall that can be spatially interpolated to provide an estimate of the...

In order to quantify the uncertainty in the prediction of three-dimensional groundwater flow and mass transport in a fractured volcanic tuff, a Monte-Carlo approach is used. An ensemble of equally likely realizations of 3-D spatially variable hydraulic conductivity is generated and used as input to groundwater flow and advective transport model.To...

The integration of radar data has been shown a powerful tool for the improvement of rainfall spatio-temporal estimation with respect to the estimation using only raingage data. However, current techniques are limited to standard cokriging algorithms and consider the samples as time independent. We propose the use of the co-located cokriging and kri...

Sequential simulation is a powerful stochastic simulation technique the theory of which relies on the ability to determine, for a given multivariate model, the conditional probability of a single random variable given any number of conditioning values. Sequential simulation can be used with those multivariate models for which these conditional prob...

This paper evaluates the performance of geostatistical methods to estimate leaf area index (LAI) fields from ground based measurements. These fields are necessary for the direct validation of high and medium spatial satellite derived products. Three models variants of the kriging technique the ordinary kriging (OK), the collocated cokriging (CKC) a...

Esta tesis con un importante aspecto relacionado con la construcción de modelos numéricos para la simulación de flujo de agua subterránea y el transporte de masa en acuíferos heterogéneos: la integración de toda la información disponible teniendo en cuenta su grado de confianza y su procedencia para la caracterización del medio físico. Esta integra...