Alfredo Ollero

Alfredo Ollero
University of Zaragoza | UNIZAR · Department of Geography and Regional Planning

PhD in Physical Geography

About

327
Publications
107,741
Reads
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1,838
Citations
Citations since 2017
70 Research Items
945 Citations
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Introduction
He incluido aquí referencias a la mayor parte de mis trabajos (dejando fuera otros divulgativos) por si pueden ser útiles. En muchos no puedo aportar el documento por carecer de permisos, o son antiguos y no están en digital. Trabajo en ríos desde 1987, con publicaciones variadas, aunque algunas (especialmente las del Ebro) un tanto repetitivas, por los muchos encargos que me hicieron. No me he esforzado por publicar en inglés: defiendo la diversidad frente a la globalización que nos imponen.
Additional affiliations
February 2002 - present
University of Zaragoza
Position
  • Professor (Associate)
March 1995 - February 2002
Universidad del País Vasco / Euskal Herriko Unibertsitatea
Position
  • Professor (Associate)
January 1992 - March 1995
environmental studies
Position
  • self employed
Education
September 1969 - June 1987
escuelas públicas de Binéfar y Calahorra / institutos públicos de Calahorra (Marco Fabio Quintiliano) y Zaragoza (Pablo Gargallo) / Universidad de Zaragoza
Field of study

Publications

Publications (327)
Book
Full-text available
Crecidas e inundaciones son procesos naturales necesarios en el planeta, que rigen y renuevan el funcionamiento de todos los cursos fluviales. La deficiente cultura ambiental de nuestro tiempo nos ha llevado a demonizar estos procesos, que eran respetados por nuestros antepasados, conscientes de los muchos beneficios que aportaban, pero que actualm...
Book
Full-text available
Los cursos efímeros (ramblas, rieras, cauces secos salvo en avenidas repentinas y eventuales) tienen una gran presencia en el territorio mediterráneo, donde constituyen la mayor parte de la red fluvial. Son sistemas naturales fundamentales en el ciclo hidrológico para el transporte de agua, sedimentos y nutrientes, y, por tanto, excelentes indicado...
Book
Full-text available
Ephemeral channels (ramblas or dry channels - except in sudden occasional flash floods) are prevalent in the Mediterranean, where they make up most of the fluvial network. They are fundamental natural systems in the hydrological cycle for transporting water, sediment and nutrients, and, therefore, are excellent indicators of climate and global chan...
Chapter
Full-text available
This book gives positive examples how humans and rivers have been, and are still in some places, living in harmony. It analyses how this knowledge can be transferred into modern river management schemes and thereby it attempts to mitigate the deplorable trend of the decline of biological and cultural heritages and diversities in and along rivers. A...
Article
Full-text available
Los datos históricos aportados por los Anuarios de Aforo permiten apreciar un contraste muy acentuadoentre los elevados caudales máximos instantáneos registrados en diferentes episodios de crecidadel río Alfambra y los valores de caudal medio diario correspondientes a la jornada en que se alcanzaese máximo instantáneo. Ello lleva a pensar que algun...
Article
Full-text available
El curso medio-bajo del río Cinca ha sufrido importantes cambios en los últimos 90 años, tanto en la geomorfología de su cauce como en la vegetación que ocupa su Territorio Fluvial. En este estudio se han analizado los cambios observados entre las fotografías aéreas de nueve fechas distintas, desde 1927 a 2018, mediante fotointerpretación. Paralela...
Preprint
Full-text available
En el mundo mediterráneo la acción antrópica sobre los sistemas fluviales es muy antigua. Los impactos sobre los ríos efímeros han sido tan importantes como en los ríos permanentes. Sin embargo, por diferentes circunstancias, inherentes tanto a sus características físicas, como a la escasa consideración que tienen para los gestores hidráulicos, se...
Chapter
Full-text available
En el mundo mediterráneo, la acción antrópica sobre los sistemas fluviales es tan antigua como la humanidad. Los impactos han afectado tanto a los ríos perennes como a los efímeros. Sin embargo, debido tanto a las características inherentes a los ríos efímeros (escasa circulación hídrica,) como a la escasa consideración por parte de la administraci...
Article
Full-text available
The hydromorphological diagnosis and assessment of rivers is a necessary procedure aimed to improve the ecological status of rivers af- fected by notable human impacts. The hydrogeomorphological index IHG was designed 15 years ago for that purpose. Its most updated version and its modality for ephemeral courses (IHG-E) are presented. All applicatio...
Article
In his comment on our recent article “Promoting fluvial geomorphology to ‘live with rivers’ in the Anthropocene Era” (García et al., 2021), Dave Rosgen (2021) suggests that we make three erroneous claims about him and his technical protocol Natural Channel Design (NCD). In this reply, we contextualize and address his comments, analysing the repeate...
Article
Full-text available
The floods of 2015 and 2018 in the Middle Ebro River have led to a rethinking and updating of the forecasting and management systems. The improvements in the flow measurement systems applied in this type of extreme phenomena have led to questioning the values that were recorded in the past, officially changing the maximum flow rates of some histori...
Article
In this research, we explore the alluviation process of an artificial side-channel built in August 2015 and designed to alleviate bank erosion risks on the main river. The study area is located on the lower Gállego River, a meandering-wandering gravel-bed river draining the Southern Pyrenees. This river reach is still dynamic (i.e. chutes, meander...
Conference Paper
Full-text available
Ephemeral rivers hydromorphological processes are intermittent and many times of fast response. Therefore they remain still quite unknown. The geomorphological mapping of river forms and geomorphological units is a useful tool to recognize the evolution, changes and the response of river adjustments of hydrological events. A diachronic geomorpholo...
Conference Paper
Full-text available
Bedload sediment transport was monitored from 2016 to 2020 in the Leitzaran River, in a reach affected by the removal of 7-meters high dam (Oioki dam). The removal was accomplished in two phases, the 3 first meters were removed in September 2018 and the second phase (September 2019) involved the removal of the remaining 4 meters. The study area was...
Article
Is geomorphology at the forefront of river management? The aims of this article are to explore potential answers to this question in terms of role, barriers, motivation and prospects for river management in the Anthropocene Era. We justify and execute our analysis, first through the growing interest in applied geomorphology and its role to improve...
Chapter
Full-text available
Los trabajos de hidromorfología fluvial en España se han desarrollado en el presente siglo y han sido abordados en su mayor parte desde la Geografía Física. Esta ciencia aporta una visión integradora de todos los factores, elementos y procesos en la dinámica fluvial, resultando muy útil en el diagnóstico del estado de los ríos y en la propuesta de...
Preprint
Full-text available
The floods of 2015 and 2018 in the Middle Ebro River have led to a rethinking and updating of the forecasting and management systems. The improvements in the flow measurement systems applied in this type of extreme phenomena have led to questioning the values that were recorded in the past, officially changing the maximum flow rates of some histori...
Chapter
Full-text available
RESUMEN La percepción sobre crecidas e inundaciones fluviales y la gestión del riesgo han estado determinadas durante décadas por una visión muy reducida y sesgada, apoyada en falsos mitos y en malas prácticas ambientales. En los últimos años se han sentado algunas bases para un necesario y urgente cambio de visión que debe ir conduciendo hacia la...
Article
Full-text available
Se presenta el proceso de trabajo para la elaboración de material didáctico a partir de herramientas de análisis geográfico. Estos materiales escolares están diseñados para trabajar en las aulas de Educación Secundaria la despoblación y el patrimonio cultural y natural en el mundo rural, como en este caso, en el “territorio mudéjar”. El objetivo es...
Article
How should the success of river and floodplain restoration be assessed? What should we be restoring? We contend that the benchmark for restoration should be the river in its “natural,” that is, quasi‐equilibrium condition prior to deliberate modification. The pre‐modification condition of the river represents a quasi‐equilibrium state in which the...
Article
Full-text available
Se incide sobre algunas malas prácticas que destruyen la geomorfología fluvial en cauces aluviales. Son actuaciones muy extendidas en el territorio y muy frecuentes, presentándose aquí dos ejemplos recientes en la cuenca del Ebro. Estas malas prácticas, que consisten en el aplanado de los lechos y en las acumulaciones de material aluvial en las már...
Article
Full-text available
The Ebro River in the Reserva Natural Dirigida de los Sotos y Galachos del Ebro has generated significant geomorphological changes due to its own functionality, standing out by its very active fluvial dynamics in the general context of the middle Ebro. The five aerial photographs of 1927, 1956, 1998, 2006 and 2015 years have permitted to evaluate a...
Conference Paper
Full-text available
Los cursos de agua efímeros del ámbito mediterráneo plantean muchas dificultades para que puedan ser objeto de programas de restauración. Los problemas derivan de la gravedad de los impactos geomorfológicos que sufren, de su funcionamiento repentino y esporádico-de ocurrencia a veces impredecible-, de su escasísima consideración en el marco de la g...
Conference Paper
Full-text available
Se estudia el transporte de carga de fondo (caudal sólido) mediante el seguimiento en un tramo del río Leitzaran afectado por la presa de Oioki. Se rastrearon 600 partículas de sedimentos utilizando técnicas RFID (radio-frequency identification) en 3 puntos diferentes: tramo control (fuera de los efectos de la presa), tramo aguas arriba y tramo agu...
Conference Paper
Full-text available
Se reflexiona sobre algunas malas prácticas que destruyen la geomorfología fluvial en cauces aluviales. Son actuaciones muy extendidas en el territorio y muy frecuentes, presentándose aquí dos ejemplos recientes en la cuenca del Ebro. Estas malas prácticas, que consisten en el aplanado de los lechos y en las acumulaciones de sedimentos en las márge...
Poster
Full-text available
A set of dimensionless morphological ratios are commonly used as a basis for studies of stream stability and natural channel restoration. Often, such ratios have been obtained from morphometric measurements made in the field and developed into a template for a given geomorphic reference site. The main objective of the present study is to analyze th...
Poster
Full-text available
A set of dimensionless morphological ratios are commonly used as a basis for studies of stream stability and natural channel restoration. Often, such ratios have been obtained from morphometric measurements made in the field and developed into a template for a given geomorphic reference site. In this study, high resolution aerial photographs from 2...
Poster
Lithological and aridity conditions in the central area of the Ebro Basin favour the abundance of intermittent and ephemeral rivers. These rivers suffer important environmental problems but lack specific scientific studies, and in most cases they are not even considered water bodies in their management. A methodological proposal is launched combini...
Article
Full-text available
This study documents the impacts of engineering works on flood risk and channel dynamics of the maximum geomorphic flow reach of the Middle Ebro River (Spain) over the last ninety years. The map reveals how the construction of transversal transport lines and their ineffective design and maintenance has contributed to an elevated risk of flooding an...
Presentation
La cartografía en general, y la cartografía digital en particular, es una de las herramientas principales en cualquier estudio relacionado con el territorio, cualquiera que sea el elemento del territorio a analizar. La cartografía topográfica, la cartografía temática, la ortofotografía, los modelos digitales nos permiten conocer desde la distancia...
Poster
Full-text available
Complete 3D models of five alluvial reaches affected by the removal of Inturia dam (Leitzaran River) have been obtained through laser scanner techniques. Removal was accomplished in four phases, 3 m per year, and completed in January 2016. Data registration started before the removal started in 2013 and every year after. Therefore erosion and sedim...
Poster
Full-text available
En Espagne, où les bois morts tombés dans les cours d'eau ont été systématiquement retirés des rivières pendant des décennies, les gens sont habitués aux rivières avec peu ou pas de bois mort. Des études antérieures ont indiqué que la perception négative du bois en rivières est liée au manque de connaissances de base sur l'écologie des cours d'eau...
Chapter
Full-text available
The frequency distribution of daily river discharge amounts almost conforms to a negative exponential distribution, reflecting the fact that there are small daily totals and few large ones. Positive exponential curves, which plot the cumulative percentages of days with discharges against the cumulative percentage of the discharge amounts that they...
Poster
The use of topographic instruments for massive data capture, like laser scanner, automatic photogrammetry or drones, is very frequent in the geometric documentation of different realities like heritage, industry or geomorphology. However, the apparent simplicity in the handling of such devices and the high speed of the measurement hides the true wo...
Article
Instream large wood (LW) is widely perceived as a source of hazard that should be avoided. This is also the case of Spain, where wood has been systematically removed from rivers for decades. Consequently, people are accustomed to rivers with minimal or no LW at all. However, the presence and transport of wood is natural and has positive ecological...
Article
River dynamics, global change and human pressure in Ebro basin, channel and delta. The river Ebro and its tributaries has undergone very remarkable changes since 1950. They have suffered marked process of simplification and stabilization, both in the main river and in its main Pyrenean and Iberian tributaries. They show important changes in the cha...
Article
Full-text available
The ecological condition and functionality of the Ebro basin’s rivers have suffered a notable deterioration in the last decades, because of the global change and anthropic pressures. Opposite to this problem, the initiatives of restoration are still scanty, local and very dispersed in the territory. Ebro basin does not stand out at present for rive...
Article
Full-text available
This article demonstrates the relationships among the elements and structures of cities built on the banks of rivers. Cultural and ideological changes and new interests add complexity and mutability, which should help to integrate elements of the past and present in an attempt to predict water courses in the future. Apart from being an exciting cha...
Article
Hydrological evolution and recent floods in the middle Ebro. Over the last decades, a decreasing trend in Ebro river annual flow contributions has been observed. However, during the last years this important river has suffered remarkable extreme flood events, a number of them outstanding, with wide sectors of floodplain flooded. These facts drove t...
Article
River classification is one of the recommendations of the European Water Framework Directive 2000/60/EC, which establishes that classifications should be carried out according to different variables hierarchically organized from a smaller to a larger scale. We suggest incorporating into the Directive’s hierarchical system a geoecological unit (lith...
Article
Full-text available
p>Se analiza la crecida del río Turia en Teruel acaecida en junio de 1933. La prensa escrita se hizo eco de una relevante crecida del río Turia con importantes efectos en las proximidades de Teruel. A partir de esa evidencia, diversas fuentes documentales permiten averiguar sus causas, estimar su volumen y conocer sus principales efectos. Esa infor...
Article
Full-text available
River restoration in Ebro basin, a synthesis. The ecological condition and functionality of the Ebro basin’s rivers have suffered a notable deterioration in the last decades, because of the global change and anthropic pressures. Opposite to this problem, the initiatives of restoration are still scanty, local and very dispersed in the territory. Ebr...
Conference Paper
Full-text available
Chile is shaped by an extensive network of coastal and Andean river basins that flow into the Pacific Ocean, thus configuring a unique geographic pattern. The fluvial system of the Andalién River is located in Concepción, one of the most developed cities in Chile, and it is a highly representative case study of what is happening now with the countr...
Article
Full-text available
The classification of rivers based on geomorphological criteria played, in the past, a secondary role for management decision making, although in the last years they have experienced a shift from the scientific field to that of the technical. Currently, managers require the most simplified form of classifications in order to use them in plans and p...
Article
Full-text available
Resumen Se trata de la fase inicial de un proyecto que busca la puesta en valor de los ríos en gravas, muy amenazados y en claro proceso de desaparición, siendo al mismo tiempo de alto valor patrimonial. Se presenta el censo y la propuesta preliminar de tipologías de los ríos de gravas en el Pirineo central aragonés. A partir de fotointerpretación...
Article
Full-text available
Hydrological and geomorphological studies have increased in recent years indicating their importance to understand the functioning of river systems. In this research, the hydrogeomorphological quality of the Utcubamba River, located in the Amazon basin, was evaluated. By applying the Hydrogeomorphological Index (IHG) along its main watercourse the...
Conference Paper
Full-text available
The methodology and results of two dam removals in two different rivers is presented and compared. One removed all-at-once and the second one in a four-stage removal process. Methodology included topographical measurements of the channel, TLS measurements of river bed and bars and sediment grain size and transport. Morphological channel adjustments...
Conference Paper
Full-text available
The application of hydrogeomorphology as a tool for river management and decision making on reference condition definition for river restoration is presented. Water Framework Directive (2000/60/CE) requires the identification of reference conditions and attainable target images, to achieve the good ecological status, taking into account the direct...
Technical Report
Full-text available
This technical report covers part of previous research conducted by the authors, presented here in four sections: Introduction, The origin of rising rivers, Mechanisms and progression of rising rivers, and Management principles for rising rivers and floods. Rises are seen as the driving force of rivers and of fluvial dynamics. They are natural phen...
Article
Dam removal has been demonstrated to be one of the most frequent and effective fluvial restoration actions but at most dam removals, especially of small dams, there has been little geomorphological monitoring. The results of the geomorphological monitoring implemented in two dams in the rivers Urumea and Leitzaran (northern Spain) are presented. Th...
Article
Full-text available
Floods modify the natural dynamics of river environments and greatly affect urban areas, especially in mountain regions where flooding is frequent because of the precipitation characteristics and orographic configuration. In this study the vulnerability of the central sector of the Pyrenees to flood events was investigated using frequency analysis...