Hervé Piégay

Hervé Piégay
University of Lyon · UMR 5600 EVS

Research Director CNRS

About

607
Publications
134,672
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
14,032
Citations
Additional affiliations
January 2007 - December 2012
January 2006 - present
October 1995 - April 2013
French National Centre for Scientific Research
Position
  • Centre national de la recherche scientifique

Publications

Publications (607)
Preprint
Full-text available
Many large European and American rivers have been channelized in the 19 th century and since then feature Dike Fields (DFs) forming engineered alluvial margins. Drivers and witnesses of contemporary geomorphological and ecosystem changes, these initially aquatic DFs have for the most been filled with fine sediments and become terrestrial. On the Rh...
Presentation
Full-text available
During the twentieth century, due to different human pressures (damming, gravel mining and bank protection), the Dordogne River (southwest of France) has recorded several morphological changes in its middle reach. To quantify and hierarch the effects of these pressures, we used a specific hypothesis-driven framework based on in situ measurements (g...
Poster
Full-text available
European and North American rivers, hydraulic structures such as groynes were commonly implemented in the 19th century in order to correct and stabilize their geometry. In the 20th century, many were equipped with dams for hydroelectric production. Working on the Rhône River which combines these two types of development, we observe a phenomenon of...
Presentation
Workshop presentation of the biological effects of gravel re-injection in the Upper Rhine
Conference Paper
Full-text available
Sur les grands cours d’eau européens et nord-américains, des champs d’épis ont couramment été implémentés au 19ème siècle afin de corriger et stabiliser leur géométrie. Au 20ème siècle, beaucoup se voient équipés de barrages pour la production hydro-électrique. Travaillant sur le Rhône qui cumule ces deux types d’aménagement, nous observons un phén...
Article
Present-day river forms and processes are in many cases conditioned by the consequences of anthropogenic modifications such as dams, embankments and gravel mining. Fluvial geomorphologists have typically investigated the effects of these human impacts using a so-called expert-based approach, whereby observed association or synchronicity between geo...
Conference Paper
Full-text available
Les aménagements à buts multiples (e.g. navigation, production hydro-électrique) ont profondément modifié la structure physique (formes) et le fonctionnement (processus) du Rhône. Face au constat de ces altérations, un programme de restauration reposant principalement sur (1) l'augmentation des débits réservés dans les vieux-Rhône ciblés et (2) le...
Conference Paper
Full-text available
Accumulated driftwood (i.e., floating trunks, downed trees, branches, and roots) upstream from dams may create obstructions, reduce spillway capacity, and cause undesired higher water levels in the reservoir. To minimize these issues, some dam managers must remove the driftwood mechanically regularly. This is the case at the Génissiat dam in the Rh...
Article
Given the actual trajectory of greenhouse gases emissions, in situ actions are needed to limit rivers water warming. Riparian tree planting has been shown as a successful mitigation strategy, but most studies have been conducted on upland forested rivers. The hydraulic, geomorphic and thermal conditions of lowland rivers, subject to straightening a...
Article
In this paper, we evaluate morphological changes related to the Plan d'Arem dam (1970), a run-of-river (RoR) dam located on the Upper Garonne (central Pyrenees), and disentangle its morphological effects from other drivers (post-Little Ice Age [LIA] climate change, changes in agricultural practice, catchment afforestation, upstream damming, and byp...
Conference Paper
Full-text available
During the twentieth century, due to different human pressures (damming, gravel mining and bank protection), the Dordogne River (southwest of France) has recorded several morphological changes in its middle reach. To quantify and hierarch the effects of these pressures, we used a specific hypothesis-driven framework based on in situ measurements (g...
Article
Full-text available
Functional characteristics of braided rivers with very high elevations (>3400 m) located in the Qinghai-Tibet Plateau, China provide unique insight into fully understanding global braided river functioning, but have not yet been explored because of their remote locations and harsh physiographic conditions. In this study, we unveiled these character...
Article
Gravel augmentation has become common practice to mitigate the effects of decline in upstream sediment supply in gravel-bed rivers. However, the functional aspects of river systems are often left out of rehabilitation monitoring programmes. Despite temperature being a fundamental parameter determining the general health of rivers, a limited number...
Article
Full-text available
Riparian vegetation encompasses dynamic communities structured by strong environmental gradients. Due to anthropogenic changes, a greater uniformity of environmental conditions is observed along local gradients. To maintain diverse and functional communities in regulated rivers, there is an urgent need to finely characterize the factors controlling...
Article
Numerous studies have highlighted the negative consequences of dams (long-term alterations of Earth systems and social and economic injustices), and have questioned the sustainability of dams, i.e., the capacity of dams to meet the social, economic, and environmental needs of the current generation without compromising the needs of future generatio...
Article
Full-text available
Fleuve fortement aménagé, le Rhône fait l’objet depuis plus de vingt ans de nombreux travaux de restauration écologique et hydraulique, accompagnés d'un programme scientifique de suivi et d'évaluation des effets des actions sur les milieux et la biodiversité. Dans ce contexte, d'anciens ouvrages de protection des berges ont été démantelés avec comm...
Article
Full-text available
Managers need to know how to mitigate rising stream water temperature (WT) due to climate change. This requires identifying the environmental drivers that influence thermal regime and determining the spatial area where interventions are most effective. We hypothesized that (i) extreme thermal events can be influenced by a set of environmental facto...
Book
Full-text available
Nous proposons dans ce guide une nouvelle approche méthodologique pour évaluer la pertinence et mettre en œuvre des « lâchers morphogènes » en aval de barrages. Ces lâchers correspondent à des débits relativement élevés lâchés par les barrages afin de générer des changements dans les caractéristiques physiques des lits fluviaux (ex., décolmatage, d...
Book
River restoration initiatives are now widespread across the world. The research efforts undertaken to support them are increasingly interdisciplinary, focusing on ecological, chemical, physical as well as societal issues. River Restoration: Political, Social, and Economic Perspectives provides a comprehensive overview of research in the field of ri...
Book
River restoration initiatives are now widespread across the world. The research efforts undertaken to support them are increasingly interdisciplinary, focusing on ecological but also societal issues. Based on a review of previous contributions, this chapter provides an overview of research in human and social sciences in the field of river restorat...
Book
This chapter presents the different perspectives proposed in this book to address the current humanities and social sciences (HSS) issues of river restoration. It highlights the way social, economic, and political perspectives contribute to scientific thinking in the field of river restoration and questions these contributions in terms of operation...
Article
Driftwood in river catchments might pose a hazard for the safety of infrastructures, such as dams and river dwellers, and thus is often removed. Génissiat dam in France presents a case study where annually approximately 1300 tons of driftwood are removed to prevent driftwood sinking and to protect the dam infrastructure. Collected river driftwood i...
Article
Full-text available
Producing hard carbon from lignocellulosic biomass has been the focus of recent studies as a promising source of anode material for Na-ion batteries. Woody biomass is a potential source, but it is already well valorised. Consequently, river driftwood can be an excellent alternative, especially since it is a disturbing waste for dam regulators. It c...
Chapter
River restoration initiatives are now widespread across the world. The research efforts undertaken to support them are increasingly interdisciplinary, focusing on ecological but also societal issues. Based on a review of previous contributions, this chapter provides an overview of research in human and social sciences in the field of river restorat...
Chapter
This chapter presents the different perspectives proposed in this book to address the current humanities and social sciences (HSS) issues of river restoration. It highlights the way social, economic, and political perspectives contribute to scientific thinking in the field of river restoration and questions these contributions in terms of operation...
Conference Paper
Full-text available
Gravel augmentation and bank (re-)erosion are increasingly performed by managers of regulated rivers to enhance bedload transport, recreate pioneer units, rejuvenate channel forms, and diversify aquatic and riverine habitats. This paper aims providing feedbacks from unprecedent restoration actions conducted along the Upper Rhine river downstream of...
Technical Report
Seignemartin G., Piégay H., Belletti B., Ghaffarian Roohparvar H., Winiarski T., Mourier B. (2021). Évolution morphologique des marges alluviales et évaluation des stocks de sédiments grossiers à Baix-Le-Logis-Neuf et Beaucaire. Rapport Final. Observatoire des Sédiments du Rhône (OSR), 5ème Programme d’Actions, 51 p. HAL Id: hal-03290964 https:...
Article
Full-text available
Wood is an essential component of rivers and plays a significant role in ecology and morphology. It can be also considered a risk factor in rivers due to its influence on erosion and flooding. Quantifying and characterizing wood fluxes in rivers during floods would improve our understanding of the key processes but are hindered by technical challen...
Article
Full-text available
We present a datalogger based on Arduino cards and commercially available tools for radio frequency identification, which we term the e-RFIDuino. Designed to be robut, easy to build and install, it detects and records the mobility of objects tagged with active transponders emitting in the ultra-high frequency domain (433.5 MHz). It functions withou...
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
Space and time analyses of channel changes, especially within large rivers subject to high levels of human impact, are critical to address multiple questions about rivers in the Anthropocene era. The reconstruction of long-term (> 150 year) evolutionary trajectories permits an understanding of how natural and anthropogenic factors impact hydromorph...
Article
Full-text available
In this study, we explore the variability of sedimentation conditions (e.g., grain-size, accumulation rate, contamination) according to fluvial depositional environments. Indeed, sediment cores are commonly used as archives of natural and anthropogenic activities in hydrosystems, but their interpretation is often complex, especially in a fluvial co...
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...
Article
Full-text available
To date, no survey on the diverse channel patterns existing prior to the major phase of river regulation in the mid-19th – early 20th century has been elaborated at the scale of the whole European Alps. The present paper fills this knowledge gap. The historical channel forms of the 143 largest Alpine rivers with catchments larger than 500 km² (tota...
Article
Flushing flows are deliberate high-flow releases designed to mimic effects of floods in removing fine sediment from downstream aquatic habitats. A special case of environmental flows, flushing flows are intended to act on geomorphic processes to mitigate ecological effects of dams. We review definitions advanced for these flows, and then propose a...
Article
Full-text available
Over the last two centuries, rivers were strongly regulated, inducing notable sedimentstarvation and flow reduction. This regulation altered aquatic habitats, biocenosis andecosystem services. Gravel augmentation (GA) is increasingly promoted to restorebedload transport, rejuvenate bed sediments and diversify aquatic and riverinehabitats. However,...
Article
Wood flux (piece number per time interval) is a key parameter for understanding wood budgeting, determining the controlling factors, and managing flood risk in a river basin. Quantitative wood flux data is critically needed to improve the understanding of wood dynamics and estimate wood discharge in rivers. In this study, the streamside videography...
Article
Full-text available
Bedload transport modelling in rivers takes into account the size and density of pebbles to estimate particle mobility, but does not formally consider particle shape. To address this issue and to compare the relative roles of the density and shape of particles, we performed original sediment transport experiments in an annular flume using molded ar...
Preprint
Gravel augmentation has become common practice to mitigate the effects of decline in upstream sediment supply in gravel-bed rivers. The success of such rehabilitation schemes relies partly on the monitoring strategy and efforts. When long-term monitoring is lacking, some aspects of rehabilitation initiatives suffer more than others, such as insight...
Article
Fluvial corridor quality assessment requires that historical data be collected at a regional scale. In this article, our goal is to assess potential map resources to explore riverscape changes at a regional network scale and to define key issues in using an automated vectorization protocol to characterize such changes on such a large scale. We cons...
Preprint
Full-text available
Space and time analyses of channel changes, especially within large rivers subject to high levels of human impact, are critical to address multiple questions about rivers in the Anthropocene era. The reconstruction of long-term (> 150 year) evolutionary trajectories permits an understanding of how natural and anthropogenic factors impact hydromorph...
Article
Full-text available
Many terrestrial ecosystems have undergone profound transformation under the pressure of multiple human stressors. This may have oriented altered ecosystems toward transient or new states. Understanding how these cumulative impacts influence ecosystem functions, services and ecological trajectories is therefore essential to defining effective resto...
Preprint
Full-text available
Wood is an essential component of rivers and plays a significant role in ecology and morphology. It can be also considered as a risk factor in rivers due to its influence on erosion and flooding. Quantifying and characterizing wood fluxes in rivers during floods would improve our understanding of the key processes but is hindered by technical chall...
Article
Whereas the geomorphic effects of in-channel mining have been widely documented, very few studies have focused on recovery trajectories after mining ended. This paper describes and quantifies the channel adjustment of extended and over-widened mining pits located in a low energy gravel-bed river, and identifies the factors that control their recove...
Article
Full-text available
https://authors.elsevier.com/a/1c3r01Dk5AOycO (free download) For eight rivers situated from northern to southern Italy, the evolutionary trajectories since the middle 19th century and the key controlling factors of channel adjustments were reconstructed using a combined diachronous-synchronous approach, integrating data from catchment-to reach-sc...
Conference Paper
Full-text available
Depuis 20 ans, la ZA Seine et la ZA Rhône ont une pratique de co-construction de leurs actions de recherche avec les acteurs des territoires concernés, d'abord autour du fleuve, puis sur l'ensemble du bassin fluvial. L'élargissement des thématiques de recherche a fait évoluer les modes de co-construction. Certaines actions de recherche ont été co-c...
Preprint
Full-text available
Bedload transport modelling in rivers, which defines the threshold for pebble movement, takes into account the size and density of pebbles, but does not formally consider particle shape. The lack of analyses evaluating the influences of shape and density on particle mobility presents a major deficiency. To address this issue and to compare the rela...
Article
How research interacts with applications in river management and restoration is a critical question within the Anthropocene era. Improved knowledge regarding the socioecological effects of river management and restoration is therefore needed to establish compromises between water uses and riverine ecosystem requirements. This special issue tackles...
Article
Full-text available
Purpose River infrastructures such as dikes, groynes, and dams are ubiquitous on most large rivers, and although their consequences on the riverbed morphology have often been studied, the effect they might have on the river floodplain and margins remains largely unknown. By investigating the structure and composition of floodplain sediments in thre...
Article
The surface of the streambed in gravel-bed rivers is commonly coarser than the underlying bed material. This surface coarsening, or ‘armouring’, is usually described by means of the ratio between surface and subsurface grain-size metrics (the ‘armour ratio’). Such surface coarsening is typical of river reaches that are degrading due to a deficit in...
Article
Full-text available
Nous proposons une nouvelle approche méthodologique pour évaluer la pertinence et mettre en œuvre des ≪ lâchers morphogènes » en aval de barrages hydroélectriques. Ces lâchers correspondent à des débits relativement élevés lâchés par les barrages afin de générer des changements dans les caractéristiques physiques des lits fluviaux (par exemple, déc...
Article
Full-text available
The motion of high Reynolds number objects at free surfaces is a general problem that has many industrial and ecological applications, such as hazard assessment due to driftwood in rivers or motion of plastic patches in the oceans. Modeling such object trajectories in a flow can be done assuming the object to be a tracer or using Newton's second la...
Article
The concept of legacy sediments, introduced in the early 2010s, is increasingly common to refer to sediment produced in watersheds within a limited period by anthropogenic disturbances. Primarily applied for cases in the USA, legacy sediment is a key concept to characterize the health of river corridors and design relevant restoration schemes. Surp...
Conference Paper
Full-text available
In the context of increasing anthropic pressures on river systems, including river regulations, landuse changes, and widespread contamination, sediment deposits can act as critical archives of the hydro-sedimentary processes and of the impact of such pressures on river corridors. Depositional environments and their degree of connectivity with the m...
Article
Wood in rivers plays a major role both ecologically and morphologically. In recent decades, due to human activities in the river channels and along the riparian zone, wood obstruction and jamming has exacerbated flooding hazards and infrastructure damage. Therefore, it is necessary to quantify the wood flux and discharge in rivers to improve wood h...
Article
Most grain size monitoring is still being conducted by manual sampling in the field, which is time consuming and has low spatial representation. Due to new remote sensing methods, some limitations have been partly overcome, but methodological progress is still needed for large rivers as well as in underwater conditions. In this paper, we tested the...
Article
One of the main drivers of overbank fine deposition and floodplain formation is the hydrological connectivity between the channel and the floodplain. Channel correction (i.e., groyne field construction within the main flow channel and secondary channel disconnections) and flow regulation can typically lead to a disconnection of riverine floodplains...
Article
Full-text available
Aims In riverine ecosystems, variations in disturbance and stress intensities along the flood gradient shape vegetation community structure. However, human modifications to the flood regime may change the magnitude of disturbance and stress, leading to different species distribution patterns along environmental gradients. We aimed to study the effe...