Raúl F. Vázquez Z. - Academia.edu (original) (raw)

Papers by Raúl F. Vázquez Z.

HAL (Le Centre pour la Communication Scientifique Directe), 2000

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Hydrological Processes, Jan 22, 2002

The present study discusses the application of the physically based distributed MIKE‐SHE code to ... more The present study discusses the application of the physically based distributed MIKE‐SHE code to a medium size catchment using different grid sizes to investigate scale effects on the model results. First a 600 m grid‐square model was calibrated. This was then subjected to a multi‐resolution (MR) validation test by using the effective parameters of the calibrated model in a 300 m and a 1200 m grid‐square model. The MR test indicated that the models for the resolutions analysed only differ marginally. Secondly, the effect of grid size on both the calibrated effective model parameters and the model performance was analysed in the scope of a multi‐calibration test in which the calibration and validation processes were kept as unique and standard as possible for every grid size. The model was calibrated and validated for every grid size against both daily catchment discharge measurements and observed water levels using both a split sample procedure and a multi‐site validation test. The investigation indicated that the best validation results, in terms of river discharge, were obtained with a 600 m grid‐resolution, independent of the stream‐flow station. This, together with the exponential increase in computation time when reducing the grid size, indicates that, for the given level of data input and quality, the model type and structure, and the time step, a 600 m grid‐resolution is most appropriate for the catchment under study. Copyright © 2002 John Wiley & Sons, Ltd.

Ingeniería del agua, Sep 30, 2004

Pueden ser remitidas discusiones sobre el artículo hasta seis meses después de la publicación del... more Pueden ser remitidas discusiones sobre el artículo hasta seis meses después de la publicación del mismo siguiendo lo indicado en las "Instrucciones para autores". En el caso de ser aceptadas, éstas serán publicadas conjuntamente con la respuesta de los autores.

Water, Apr 30, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Hydrology and Earth System Sciences, Mar 31, 2000

Hydrology, 2003

... Land use was classified in five groups according to the CORINE Land Cover project, but using ... more ... Land use was classified in five groups according to the CORINE Land Cover project, but using only the first level of the ... The MIKE 11 NAM module The NAM module (DHI, 1999) of theMIKE-11 code (Havnø et al., 1995) was used for the rainfall-runoff simulation. ...

Iawa Journal, 2019

Relict tree species in the Andean mountains are important sources of information about climate va... more Relict tree species in the Andean mountains are important sources of information about climate variability and climate change. This study deals with dendroclimatology and growth patterns in Polylepis reticulata Hieron., growing at high elevation (mean of 4000 m a.s.l.) in three sites of the Ecuadorian Andes. The aims of the research were: (i) characterizing tree-ring boundaries; (ii) describing tree-ring patterns of the study sites; (iii) investigating the relationships between climate and radial tree growth; and (iv) determining the spatial correlation between seasonal climatic factors and tree-ring width of P. reticulata. Tree rings were characterized by semi-ring porosity and slight di ferences in bre wall thickness between latewood and subsequent earlywood. In all sampling sites, tree rings in heartwood were more clearly visible than in sapwood. Tree-ring width was more related to temperature than to precipitation, with growth being also a fected by site conditions and stand structure, as well as other local factors. No signi cant relationships were found between tree-ring chronologies of P. reticulata and El Niño-Southern Oscillation (ENSO) and Vapour Pressure De cit indices. The study highlights that there is not a clear driving climate factor for radial growth of P. reticulata. Additional research is needed to study growth dynamics of this species and the impacts of local environmental variables.

Hydrological Processes, 2008

This paper suggests a multi‐criteria protocol for appropriately evaluating the predictions of hyd... more This paper suggests a multi‐criteria protocol for appropriately evaluating the predictions of hydrologic models during calibration and evaluation stages. The protocol includes different statistical, analytical and visual criteria such as analysis of peak and low flows, cumulative volumes, extreme value statistics, performance statistics, etc. Furthermore, the protocol assesses the physical consistency of model predictions by filtering the total observed hydrograph into different flow‐components (baseflow, interflow and overland flow) and using these filtered data in the calibration and evaluation processes. Based on the distributed modelling of a medium size catchment, it is shown that application of the suggested protocol, and in particular the use of the filtered flow‐components in model calibration, enhances the physical consistency of model predictions, adding considerable value to the calibration process. Copyright © 2007 John Wiley & Sons, Ltd.

Journal of Hydrology, May 1, 2014

A joint deterministic-stochastic protocol based on Monte Carlo simulations (MCS) was applied to t... more A joint deterministic-stochastic protocol based on Monte Carlo simulations (MCS) was applied to the modelling of a medium size catchment using two significantly different sets of potential evapotranspiration (ET p) data, estimated through a Penman-based method. Modelling error was accounted using the Generalised Likelihood Uncertainty Estimation (GLUE) methodology. Both, water routing and water balance related parameters were considered in the analysis. The research revealed that the hypothesis of the less correct ET p data set being appropriate for the current modelling could not be rejected since model parameters adjusted to compensate for the use of significantly different ET p data sets. The GLUE analysis demonstrated that the model predictions exhibited some sensitivity to the hydraulic conductivity of one of the geological layers. Furthermore, the study revealed a considerable error attached to the simulation of both high and low flows, as well as, piezometric levels, for every ET p data set, which was most likely magnified by the coarse time and spatial scales used in the current modelling.

Journal of Hydrologic Engineering, Feb 1, 2011

To better handle landscape heterogeneities in distributed hydrological modeling, an earlier work ... more To better handle landscape heterogeneities in distributed hydrological modeling, an earlier work proposed a discretization based on nested levels, which leads to fully unstructured modeling meshes. Upon such a discretization, traditional numerical solutions must be adapted, especially to describe lateral flow between the unstructured mesh elements. In this paper, we illustrated the feasibility of the numeric solution of the diffusion equation, representing groundwater flow, using unstructured meshes. Thus, a two-dimensional ͑2D͒ groundwater model ͑BOUSS2D͒, adapted to convex unstructured and irregular meshes was developed. It is based on the approximation of the 2D Boussinesq equation using numeric techniques suitable for nonorthogonal grids. The handling of vertical and horizontal aquifer heterogeneities is also addressed. The fluxes through the interfaces among joined mesh elements are estimated by the finite volume method and the gradient approximation method. Comparisons between the BOUSS2D predictions and analytical solutions or predictions from existing codes suggest the acceptable performance of the BOUSS2D model. These results therefore encourage the further development of hydrological models using unstructured meshes that are capable of better representing the landscape heterogeneities.

Maskana, Jun 25, 2011

The overall performance of a wastewater treatment plant is in addition to the effectiveness of th... more The overall performance of a wastewater treatment plant is in addition to the effectiveness of the biokinetic processes controlled by the flow dynamics. A wide used technique to characterize the water flow dynamics is the use of tracers. At full-scale tracer experiments in wastewater treatment plants provide insufficient information to completely grasp the flow dynamics. Additionally results are often biased by uncontrolled external factors. As alternative, computational fluid dynamic (CFD) models for performance analysis of existing and the design of new wastewater treatment plants have been increasingly used over the last decade. The paper presents the results of a tracer experiment against the output of a CFD model with application to a 7 ha large maturation pond. The tracer study was conducted with the fluorescence dye Rhodamine WT using the stimulus response technique. The three dimensional CFD model was built considering a variable density distribution of spatial grids based on the specific characteristics of the system. For the unsteady flow simulations the turbulence model k- was adopted. Residence time distribution (RTD) generated by both approaches were compared and showed fairly good agreement. The velocity and turbulence profiles of the CFD model were compared with experimental data confirming, although the high computational demand, the robustness of the used CFD model.

Journal of Irrigation and Drainage Engineering-asce, Feb 1, 2004

To support a sensitivity analysis in the framework of catchment modeling, three potential evapotr... more To support a sensitivity analysis in the framework of catchment modeling, three potential evapotranspiration (ET p) scenarios were generated by means of two Food and Agriculture Organization ͑FAO͒ approaches, namely, the FAO-24 and the FAO-56 approaches. The crop ET p was estimated as a function of the reference evapotranspiration (ET o) by means of the k c-ET o approach. Scenario A was generated with the standard FAO-24 approach; Scenario B considered also the FAO-24 approach, but with some nonstandard parameters. Scenario C considered the standard FAO-56 approach. The ET o data were compared to point-scale ET o constraints. The annual cumulative value of ET o from Scenario A was on average approximately 200 mm larger than the values from Scenarios B and C. The research revealed similar ET o estimates for Scenarios B and C. The research also assessed the performance of the angstrom approach for estimating incoming solar radiation (R s). In this context, a set of angstrom coefficients was derived by means of an optimization process that considered available R s data.

Journal of Hydrology, Feb 1, 2007

... codes such as TOPOG (Vertessy et al., 1993) and TOPMODEL for examining the effects of both th... more ... codes such as TOPOG (Vertessy et al., 1993) and TOPMODEL for examining the effects of both the scale of the input elevation data and the resolution of the ... However, published modelling studies using MIKE SHE with coarse DEMs have not addressed explicitly either of ...

ABSTRACT The effect of few techniques for deriving a Digital Terrain Model (DTM) on the distribut... more ABSTRACT The effect of few techniques for deriving a Digital Terrain Model (DTM) on the distributed modelling of a medium size catchment was investigated. For assessing the DTM elevations, they were compared not only to the elevation data but also to each other. Besides simple DTM statistics, additional geomorphic relationships were investigated. In a broad scale, there is only a marginal difference between the elevation data and the DTMs. However, the output of one of the approaches seems to include a significant load of artificial artefacts included by the interpolation technique such as pits and drainage patterns. Paradoxically, the study revealed that the streamflow simulation associated to such output was the most acceptable, stressing at this way the necessity of a DTM assessment before accepting encouraging model performances due to wrong data descriptions. The study also revealed a significant effect on the prediction of piesometric levels linked mainly to the elevation discrepancies among the different DTMs and to the different values adopted by the effective parameters after the independent calibration of the different models.

Water, Mar 26, 2022

Water, Oct 21, 2022

Maskana, Jan 5, 2016

modelaron aplicando el código distribuido y basado en la descripción de procesos físicos MIKE SHE... more modelaron aplicando el código distribuido y basado en la descripción de procesos físicos MIKE SHE. La calibración y posterior validación del modelo se llevaron a cabo mediante un análisis temporal y uno espacial. Adicionalmente, se realizó un análisis de sensibilidad de las predicciones del modelo modificando los valores de los parámetros calibrados, el mismo que sugiere que el parámetro más sensible a las predicciones de flujo superficial y subterráneo es el coeficiente de conductividad hidráulica horizontal debido a la gran influencia de la capa cárstica modelada, lo cual tiene congruencia con lo observado en campo. Las predicciones tanto superficiales como subterráneas obtenidas pueden considerarse como aceptables, lo cual alienta el potencial empleo del modelo desarrollado en tareas futuras de planeamiento y gestión de los recursos hídricos. Palabras clave: Modelización, MIKE SHE, modelo distribuido, modelo basado en principios físicos, análisis de sensibilidad, hidrogeología.

DOAJ (DOAJ: Directory of Open Access Journals), 2016

RESUMEN El modelo Mecanicista Basado en Datos (DBM) se ha utilizado conjuntamente con el filtro d... more RESUMEN El modelo Mecanicista Basado en Datos (DBM) se ha utilizado conjuntamente con el filtro de Kalman (como una técnica de asimilación de datos) para la predicción de caudales en una subcuenca ubicada en la parte alta de la cuenca del río Paute. Los resultados sugieren que el modelo DBM, conjuntamente con la técnica de asimilación de datos empleada, produce predicciones de mejor calidad en la subcuenca de estudio, en comparación al uso exclusivo del modelo DBM; de hecho, el filtro de Kalman provee una medida de la incertidumbre asociada al empleo del modelo DBM para efectuar pronósticos de caudales. Estos resultados, no solo que alientan el uso futuro de modelos basados en técnicas de minado de datos, sino que además alientan el uso de la herramienta actual tanto para realizar predicciones como para el pronóstico y alerta temprana en cuencas Andinas. Palabras clave: Modelización numérica; DBM; asimilación de datos; función de transferencia (TF); parámetros dependientes de estado (SDP).

Maskana, Dec 22, 2010

RESUMEN A pesar de su importancia, la hidrología de las cuencas de los Andes se conoce pobremente... more RESUMEN A pesar de su importancia, la hidrología de las cuencas de los Andes se conoce pobremente. Por ello, ante la creciente demanda de la sociedad por una explotación sostenible de los recursos hídricos y la conservación de cuencas altoandinas del Austro Ecuatoriano, es necesario emprender iniciativas de investigación para conocer, entre otros aspectos, las interrelaciones entre el clima y la hidrología de páramos y su capacidad de producción de agua. En este contexto, el presente artículo describe las experiencias de modelación hidrológica de una microcuenca altoandina ubicada al sur oeste de Cuenca (Ecuador), presentando el detalle del desarrollo del modelo en base a un código conceptual, agregado (NAM), así como algunos resultados preliminares de la modelación. El protocolo de modelación incluyó una aproximación determinista/estocástica en base a simulaciones Monte Carlo. Los resultados de la modelación son halagadores, lo cual alienta una revisión de la versión actual del modelo, incluyendo en el mismo la nueva información que se recabe en un futuro próximo, así como la aplicación del código hidrológico a otras subcuencas y cuencas altoandinas de interés.