António N. Pinheiro

University of Lisbon | UL · Civil Engineering, Architecture and Georesources

The artificial pulsed-flows impact associated with hydropower production on the downstream biological and physical processes has been extensively addressed, showing that it may cause fish drift while changing fish habitat selection toward lower water velocity patches, acting as refuge areas. We aimed to evaluate the attraction efficiency of two flo...

Throughout the world, emerging barriers in river systems block longitudinal connectivity for migrating fish, causing significant impacts by precluding them from carrying out vital life cycle activities. Fishways are still the main mitigation solution implemented, where barrier removal is not feasible. Within the multiple technical fish passage devi...

Hydropower can have significant impacts on riverine ecosystems due to hydropeaking (i.e., artificial rapid and short-term fluctuations in water flow and water levels downstream and upstream of hydropower stations) that negatively affect downstream fish. However, when it comes to analyzing species habitat use and availability above and below small h...

River artificial fragmentation is arguably the most imperilling threat for freshwater- dependent fish species. Fish need to be able to freely move along river networks as not only spawning grounds but also refuge and feeding areas may be spatially and temporally separated. This incapacity of free displacement may result in genetic depletion of some...

É hoje consensual que a alteração dos regimes naturais de caudais promovida pela ação do homem é uma das principais pressões sobre os ecossistemas fluviais a nível mundial. Por esse motivo, e para mitigar os impactes dessas pressões sobre os ecossistemas aquáticos e ribeirinhos, têm vindo a ser desenvolvidos esforços continuados no sentido de quant...

Rivers have always been closely related with society development wich has resulted in a a high degree of human induced impacts forced upon freshwaters. Among all the pressures, river network fragmentation by artificial barriers is considered one of the most damaging, especially for freshwater fish species that see their longitudinal movements impar...

The need to increase hydropower production to reduce CO2 emissions, while supporting the development of self-sustainable fish populations in a cost-effective way, protect biodiversity and restore water-related ecosystems is urgent and recognized in the UN Agenda 2030 and in the recently launched European Green Deal. Despite the growing awareness of...

Hydropeaking negatively affects fish assemblages, but knowledge gaps still constrain our ability to rank and mitigate the impacts of different hydropower operation regimes at particular power plants. This is especially relevant for species and rivers for which the effects of hydropeaking are less investigated, such as the Iberian cyprinids and Medi...

Special Session: Ecohydraulics 2021: Novel methods to investigate flow-biota interactions numerically, in the lab and in the field Abstract Rivers are affected by a vast number of artificial barriers that block fish movements within river networks, preventing several freshwater dependent fish species from completing their life cycle. Fish need to b...

Hydropeaking negatively affects fish assemblages, but knowledge gaps still constrain our ability to rank and mitigate the impacts of different hydropower operation regimes at particular power plants. This is especially relevant for species and rivers for which the effects of hydropeaking are less investigated, such as the Iberian Cypriniformes and...

The objective of this study is to make a comparison between two 3D CFD platforms: OpenFOAM (free and open-source CFD software) and FLOW-3D (closed source commercial CFD software), focusing on vertical slot fishways, one of the most widespread solutions to facilitate the fish migration through transversal obstacles in rivers. Considering previous co...

Hydropeaking caused by small‐scale hydropower plants creates rapid changes in the intensity, frequency, and persistence of river flows. These changes can induce stress in fish across all life‐stages and, may negatively impact fish communities. Rapid increases in the flow velocity may cause fish to avoid unstable habitats, seeking out nearby refuges...

Diversos estudos têm reportado sérias alterações nas comunidades piscícolas fortemente relacionadas com a presença de barreiras transversais ao longo dos cursos de água. Comparativamente com o conhecimento sobre os impactes nas populações piscícolas dos grandes empreendimentos hidráulicos, como as barragens, os pequenos açudes (< 5 m de altura) têm...

In this study, the 3D numerical modelling of flow in a pool-type fishway with bottom orifices was performed using computational fluid dynamics (CFD) software (FLOW-3D®). Numerical results were compared with experimental data obtained from acoustic Doppler velocimetry (ADV) and particle image velocimetry (PIV) measurements. Several hydrodynamic vari...

Requalification of low-head ramped weirs through the addition of substrates (retrofitting) has attracted attention in recent years. However, few studies are available on how this measure affects the negotiation of ramped weirs by fish. This study aimed to assess the performance of an experimental ramped weir (3.00 m long with 10% slope; 0.30 m head...

The general perception of small run-of-river hydropower plants as renewable energy sources with little or no environmental impacts has led to a global proliferation of this hydropower technology. However, such hydropower schemes may alter the natural flow regime and impair the fluvial ecosystem at different trophic levels. This paper presents a glo...

Pool-type fishways have been increasingly tested to improve fish passage performance and minimize migration delays. Designing cost-effective fishways is essential for a trade-off between water uses and successful longitudinal connectivity restoration. The multislot fishway (MSF) concept, which operates with 30–50% lower discharge than a vertical sl...

A novel study that focuses on the capacity of vegetation to provide shelter for fish species under hydropeaking regimes is presented. Two artificial patches mimicking the structure and density of Carex sp. mats were installed in an experimental flume to test whether submerged plants can offer flow refuge to two cyprinid species, Luciobarbus bocagei...

The proliferation of Run-of-River (RoR) hydropower to fulfill pre-defined sustainability development goals and increasing demands for renewable energy may conflict with riverine ecosystem conservation objectives if environmental flows (e-flows) are not adequately set. Lack of a systematic methodology to define e-flows in RoR hydropower plants may c...

The water-energy-ecosystem nexus represents a complex interlinkage that depends on the flow regime type. Inadequate environmental flows setting may adversely affect the riverine ecosystem and/or hydropower revenue. This issue was addressed quantitatively in this study by considering a run-of-river hydropower plant located in a river of the Tagus ba...

Hydropeaking is an anthropogenic regime that results from the strong flow variations in the receiving waters of storage hydropower plants. These variations are due to flexible energy production, i.e. the sudden increase of electricity demands or from its decrease, affecting the fish assemblages of that river stretch. We evaluated the mitigation pot...

Downstream of small-scale hydropower plants (SHPs), the intensity, frequency and persistence of hydropeaking events often cause an intolerable stress on fish of all life stages. Rapid increases in flow velocity result in fish avoiding unstable habitats and seeking refuge to reduce energy expenditure. To understand fish movements and the habitat use...

A large share of future European hydropower projects will be run-of-the-river schemes. To understand the potential for RoR hydropower development and modernization of the technology as an opportunity for sustainable decentralization, we use the Q-methodology to compare public values about RoR hydropower in German, Portuguese and Swedish case studie...

The rapid river flow variations due to hydropower production during peak demand periods, known as hydropeaking, causes several ecological impacts. In this study, we assessed the potential of an overhead cover and velocity-refuge structure in an indoor flume as an indirect hydropeaking mitigation measure for the cyprinid species Iberian barbel (Luci...

Due to peak electricity demand, hydropeaking introduces rapid and artificial flow fluctuations in the receiving river, which alters the river hydromorphology, while affecting the downstream ecological integrity. The impacts of hydropeaking have been addressed in flumes and in rivers. However, few studies propose mitigation solutions based on fish r...

The addition of substrates to small instream obstacles, like low-head ramped weirs, has been considered a useful management solution to retrofit those structures and enhance fish passage. Substrate dimensions and spatial arrangement, together with discharge, and consequently water depths, appear as important factors for the creation of hydrodynamic...

Os pequenos açudes rampeados constituem um dos obstáculos fluviais mais comuns aos movimentos das espécies piscícolas. A transponibilidade destas estruturas, em que a água passa sobre as mesmas, mas não gera uma queda vertical, é sobretudo afetada pelo comprimento e declive da respetiva rampa. Contudo, a contribuição relativa destes fatores raramen...

Os pequenos açudes rampeados constituem um dos obstáculos fluviais mais comuns aos movimentos das espécies piscícolas. A transponibilidade destas estruturas, em que a água passa sobre as mesmas, mas não gera uma queda vertical, é sobretudo afetada pelo comprimento e declive da respetiva rampa. Contudo, a contribuição relativa destes fatores raramen...

Storage hydropower plants causes artificial sub-daily flow fluctuations in the receiving waters – hydropeaking, which leads to quickly rising and falling river flows, potentially causing serious ecological impacts, particularly on fish. Thus, it is necessary to establish effective mitigation measures in peaking rivers. Indirect measures, such as th...

Low-head ramped weirs are one of the most common small engineered structures present in Iberian rivers. Fish passability of these obstacles, where water passes over but does not generate a waterfall, is primarily related to ramp length and slope. However, the relative contribution of these factors has seldom been investigated. This study aims to as...

Hydropower plant (HPP) operations, in response to variations in market energy demand and electricity production, can generate rapid and frequent fluctuations of discharge in rivers downstream. This phenomenon, termed hydropeaking, may negatively impact fish populations. The present study aims to investigate the effects of hydropeaking on the Iberia...

Introduction Several studies reported that run-of-river (RoR) hydropower plants cause considerable alteration of natural flow regime in the diverted river reach, which may result in degradation of the habitat condition (Anderson et al. 2015). Usually, the environmental flow methods (EFMs) applied for environmental flow releases (e-flow) in case of...

Increasing demand for renewable energy has led to a massive expansion of the small-scale hydropower plants and particularly those of run-of-river type. Meanwhile, the awareness concerning river conservation and restoration is being continually increasing. This study focuses on the assessment of environmental flows releases and energy production con...

Low-head ramped weirs are a common instream obstacle to fish movements. Fish passability of these structures, where water passes over but does not generate a waterfall, is primarily related to ramp length and slope, but their relative contribution has seldom been considered. This study aims to assess the passage performance of a potamodromous cypri...

Hydropeaking is the rapid change in the water flow downstream of a hydropower plant, driven by changes in daily electricity demand. These fluctuations may produce negative effects in freshwater fish. To minimize these impacts, previous studies have proposed habitat enhancement structures as potential mitigation measures for salmonids. However, the...

L. bocagei physiological and behavioural data collected. (XLSX)

Data obtained from the fish-inspired lateral line probe (LLP). (XLSX)

Contour representation of mean front fluctuations (p¯'12). (EPS)

Contour representation of mean pressure asymmetry (Δp¯1−6). (EPS)

Contour representation of mean front pressure (p¯12). (EPS)

New engineering solutions are required to minimise the effects of an increasing number of anthropogenic barriers on watercourses. Longitudinal connectivity must be provided through fishways to allow free passage for the whole fish community. Recently, a multislot fishway (MSF) was developed, with two consecutive vertical slots that divide the overa...

Hydroelectric power plants managed in response to sub-daily changes of the electricity market undergo rapid variations of turbine discharge, entailing quickly fluctuating water levels downstream. This operation regime, called hydropeaking, causes numerous adverse impacts on river ecosystems. The hydrological alterations which affect hydropeaking ri...

Adequately designed fishways mitigate the negative effects of barriers in rivers, restoring longitudinal con-nectivity. To do so, they must present suitable hydraulic conditions, with velocity and turbulence fields adequate for multiple fish species. In the present study, numerical modelling was used to compare the hydrodynamics of two widely used...

Contrary to the vast literature on dams, much less is known about the effects of small weirs on fish movements. This study aims to evaluate the upstream and downstream passage of the Iberian barbel (Luciobarbus bocagei), when facing a small broad-crested experimental weir with varying widths of the weir crest (W) and discharges (Q). Nine configurat...

Fish responses to hydropeaking may range from sub-organismal adjustments to key life-event changes. It is currently difficult to quantify these responses and to assess the potential of artificial refuges accordingly. To address this problem, two experimental trials were conducted in an indoor flume. In the first, two hydropeaking events were tested...

Providing suitable hydraulic conditions in fishways for native freshwater species with different morphological and ecological characteristics is vital for re-establishing river longitudinal connectivity. Accomplishing this using as less water as possible without compromising its effectiveness is very important in water scarcity regions. 3D-CFD mode...

Hydropower plant (HPP) operations in response to variations in market energy demand and electricity production can generate rapid and frequent fluctuations of discharge in the river, downstream the HPP. The phenomenon, so-called hydropeaking, may result in a negative impact to fish populations. The present study aims to investigate the effects of h...

In Mediterranean regions and other areas with water scarcity, discharge-efficient passage systems are required to reestablish longitudinal connectivity to migratory fish. The present study compares the passage performance of the Iberian barbel (Luciobarbus bocagei), a potamodromous cyprinid, negotiating two different types of vertical slot fishways...

Developing and testing new fishway designs is important to improve these facilities. Discharge-efficient passage systems are required in Mediterranean regions and other areas with dry climates. The present study compares the passage performance of the Iberian barbel, Luciobarbus bocagei (Steindachner, 1864), a potamodromous cyprinid, negotiating tw...

Hydropeaking is a phenomenon during which the base flow is disrupted by intense and short-duration discharge fluctuations resulting from high-head hydropower production. However, this operation scheme affects downstream river ecosystems. Among others, rapid flow increase, i.e., upramping, can induce macroinvertebrate drift, as well as displace fish...

The presence of small weirs, far more numerous than dams, have altered the river systems and negatively affected fish communities, mainly by disturbing fish movements. However, contrarily to the vast literature on dams, much less is known about the effects of small weirs on fish movements. This study aims to evaluate the upstream passage performanc...

The rapid flow fluctuations experienced downstream of hydropeaking facilities can alter the river hydromorphology. Given the dependence of riverine fish on physical habitat, those alterations have the potential to change the physiology and behaviour of fish. We assessed whether artificial velocity refuges mitigated the physiological and behavioural...

Most fishway studies are conducted during the reproductive period, yet uncertainty remains on whether results may be biased if the same studies were performed outside of the migration season. The present study assessed fish passage performance of a potamodromous cyprinid, the Iberian barbel (Luciobarbus bocagei), in an experimental full-scale verti...

Inúmeros estudos têm reportado sérias alterações nas comunidades piscícolas fortemente relacionadas com a presença de barreiras transversais ao longo dos cursos de água. Mesmo os pequenos açudes, considerados como barreiras a priori permeáveis à movimentação dos peixes, podem provocar sucessivas perdas de conectividade com consequências negativas n...

A operação de um aproveitamento hidroelétrico em resposta às variações do equilíbrio produção/consumo de eletricidade pode gerar alterações rápidas e frequentes no caudal e na cota da superfície livre do curso de água a jusante. O fenómeno, designado por hydropeaking, tem consequências no ecossistema aquático, com especial incidência na fauna piscí...

The cover image, by S.D. Amaral et al., is based on the Research Article To swim or to jump? Passage behaviour of a potamodromous cyprinid over an experimental broad-crested weir, DOI 10.1002/rra.3232.

Environmental flows remain biased toward the traditional biological group of fish species. Consequently, these flows ignore the inter-annual flow variability that rules species with longer lifecycles and therefore disregard the long-term perspective of the riverine ecosystem. We analyzed the importance of considering riparian requirements for the l...

Physical stressors, such as man-made obstacles, are considered one of the main causes that negatively affect freshwater fish. Even small weirs may impact fish populations, including potamodromous cyprinids, by partially or totally blocking upstream migratory movements. Some studies have addressed the effect of key hydraulic parameters on upstream m...

Two-dimensional (2-D) numerical simulation and habitat suitability curves for brown trout in the Lima River in northern Portugal were used to predict the velocity suitability index (VSI) for various fish shelter configurations. The modeling results were plotted against fish frequentation rates obtained from previous research for juvenile brown trou...

In this study, different hydropower plant operation scenarios were proposed to assess the best habitat alternative for juvenile and adult brown trout (Salmo trutta). Habitat preferences were determined based on field data collection and translated into fuzzy sets and rules for both life-stages. The River2D model was applied to a 100-m long stream s...