Isabel Boavida

University of Lisbon | UL · Civil Engineering Research and Innovation for Sustainability

As the share of renewable energy grows worldwide, flexible energy production from peak-operating hydropower and the phenomenon of hydropeaking have received increasing attention. In this study, we collected open research questions from 220 experts in river science, practice, and policy across the globe using an online survey available in six langua...

Hydropeaking, which refers to large and rapid flow fluctuations caused by the turning on or off of hydro-turbines to generate electricity, is a topic of growing interest due to its impact on fluvial ecosystems. To date, most hydropeaking studies have focused on the impact of this hydropower operation mode on invertebrate and fish communities, but l...

Dam construction and streamflow regulation are increasing throughout the world, with impacts in impounded aquatic ecosystems. Hydropower dams, some of them causing a phenomenon called “hydropeaking” during their operation, are known for having a variety of impacts on downstream aquatic biota, particularly fish, and respective habitat. This can resu...

As the share of renewable energy grows worldwide, flexible energy production from peak-operating hydropower and the phenomenon of hydropeaking have received increasing attention. In this study, we collected open research questions from 220 experts in river science, practice, and policy across the globe using an online survey available in six langua...

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...

An increase in the demand for renewable energy is driving hydropower development and its integration with variable renewable energy sources. When hydropower is produced flexibly from hydropower plants, it causes rapid and frequent artificial flow fluctuations in rivers, a phenomenon known as hydropeaking. Hydropeaking and associated hydrological al...

Hydropeaking is part of hydropower production. The discontinuous release of turbined water during hydropeaking generates sudden rise and falls of the water levels, as well as extended droughts. These artificial flow fluctuations impose challenging growing conditions for riverine vegetation. In order to identify vulnerable/resistant plant species to...

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...

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...

Hydropeaking research has generated unprecedented scientific discussion in the last twenty years and improved our understanding of the processes resulting from hydropeaking by strengthening the links between basic knowledge and practical applications. Given the reportedly increase in hydropeaking operations and applications in recent years, this Sp...

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...

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...

Rivers have been intensively degraded due to increasing anthropogenic impacts from a growing population in a continuously developing world. Conflict demands on freshwater resources, exacerbated by climate change, present a difficult dilemma for scientists and managers: until when and how much can a river (and its natural flow regime) be altered, wh...

The flow regime is a determinant of the ecological function and natural dynamics of a river system with a prominent effect on freshwater fish. Here, we introduce a number of contributions to the Special Session, “Ecohydraulics of river flow alterations and impacts on freshwater fish,” that occurred at the XIX Conference of the Iberian Association o...

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...

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...

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...

Peak-operating hydroelectric power plants allow the production of flexible energy and are, therefore, considered the backbone of the energy grid. However, their operation regime – called hydropeaking – is one of the greatest stressors on riverine ecosystems, whereby aquatic biota and their life cycle stages can be affected by various components of...

Peak-operating hydropower plants are usually the energy grid’s backbone by providing flexible energy production. At the same time, hydropeaking operations are considered one of the most adverse impacts on rivers, whereby aquatic organisms and their life-history stages can be affected in many ways. Therefore, we propose specific seasonal regulations...

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)

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...

D2.1 A list of solutions, models, tools and devices, their application range on a regional and overall level, the identified knowledge gaps and the recommendations to fill these.

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...

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...

Freshwater fish from the Mediterranean region are amongst the most threatened species worldwide due to increasing river degradation. Because of such threats, the number of river restoration projects has greatly increased. However, they are seldom planned with inputs from the species' life history, often resulting in erroneous practices that failed...

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 Baixo Sabor hydroelectric scheme was recently constructed (began operating in 2015), blocking fish migration immediately at the river mouth. As a compensation measure for spawning habitat loss the Vilariça River which confluences with Sabor River, immediately downstream from the Baixo Sabor scheme, was chosen for rehabilitation site as an attem...

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...

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...

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...

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...

Endemic freshwater fish from the Mediterranean region are among the most threatened species in the world owing to increasing river degradation. Because of such threats, the number of river restoration projects has greatly increased. However, they are seldom planned with consideration of the species' life history, often resulting in erroneous practi...

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...

Environmental flows remain biased toward the traditional biological group of fish species. Accordingly, these flows ignore the inter-annual flow variability that rules species with longer life cycles, thereby disregarding the long-term perspective of the riverine ecosystem. We analyzed the influence of considering riparian requirements for the long...

An experimental factorial approach, in terms of habitat use and movements by Atlantic salmon parr (Salmo salar), was studied in response to induced peaking flow in a bypass river section in southern Norway. Sixteen radio-tagged salmon parr (mean TL 12.9 ± 0.8 cm) were tracked during a 7-day spring period with manipulations of flow. Total habitat av...

Os regimes de caudais ecológicos aplicados em Portugal, com base em métodos de simulação de habitat, mantêm-se enviesados para o tradicional grupo biológico da fauna piscícola e ignoram a variabilidade interanual característica dos regimes hidrológicos naturais, privando os atuais regimes de caudais ecológicos de uma perspetiva de longo prazo do ec...

Due to hydropower operation, base flow is periodically disrupted by extreme and short-duration fluctuations of discharge during daily peaks of energy demand. This severely affects the aquatic ecosystem. To reduce this effect, structural and operational measures have been proposed. The implementation of operational measures has been neglected due to...

The overexploitation of water resources has disrupted the natural flow variability and induced drastic changes in the ecological processes of riverine ecosystems. Hydropower production results in daily energy peaks (hydropeaking) with the release of artificial downstream discharge peaks, with subsequent negative effects on the abiotic components an...

Environmental flows remain biased towards the traditional fish biological group and ignore the inter-annual flow variability that rules longer species life cycles, thus disregarding the long-term perspective of the riverine ecosystem. Incorporating riparian vegetation requirements into environmental flows could bring an important contribute to fill...

Despite the growing awareness of the hydropeaking impacts on freshwater fish, few studies report habitat mitigation measures and evaluate fish behaviour according to those. The aim of this work is to assess the movement behaviour of cyprinids exposed to peak flows in an experimental flume and propose habitat mitigation measures. It presents a novel...

Located in a sensitive Natura 2000 protected area, the construction of the River Odelouca dam in the Algarve region of southern Portugal was subject to diverse compensation measures, including environmental requalification of selected river segments. We cover the whole sequence of the project: a) characterization and selection of reaches to rehabil...

Hydropeaking occurs due to hydropower plant operation, when high discharges are made at a daily regular basis during high electricity consumption periods. It severely affects the hydrologic regime and, consequently, the aquatic ecosystem. To mitigate this tendency, either structural or operational measures have been proposed. Usually, structural me...

The effects of hydropeaking in the habitat of the Iberian barbel (Luciobarbus bocagei) a native cyprinid fish species of the Iberian Peninsula, was investigated. Two study sites were selected in the Ocreza River, Mid-Eastern Portugal. A regulated site located immediately downstream from a hydropower dam, and an unregulated site located on a lotic u...

Hydropeaking flows often place an intolerable stress on fish. The creation of lateral fish shelters has been pointed out as a most promising mitigation measure to protect fish species from peak flows. Therefore is crucial to determine the design guidelines for the shelters in order to maximize the habitat availability. 2D hydrodynamic numerical mod...

Univariate functions, like the Habitat Suitability Criteria (HSC) for each species life-stage, consider separate effects of individual parameters. Other than using independent univariate functions, knowledge-based models as the fuzzy logic approach are based in the establishment of fuzzy sets and rules for each species life-stage built on a fish bi...

Over the years, the need to sustain and maintain the aquatic ecosystems has been widely recognized and embraced by river managers and environmental policies and legislation. In particular, minimum flow regimes have been determined and implemented all over the world. The Instream Flow Incremental Methodology (IFIM), one of the most used methodologie...

Environmental flows essentially consider intra-annual cycles and disregard the inter-annual variability existing on fluvial systems. Current approaches neglect flow components which are of extreme importance to maintain biophysical and ecological processes of groundwater and riparian ecosystems, while concentrating mostly on instream features. The...

Environmental flows essentially consider intra-annual cycles and disregard the inter-annual variability existing on fluvial systems. Current approaches neglect flow components which are of extreme importance to maintain biophysical and ecological processes of groundwater and riparian ecosystems, while concentrating mostly on instream features. The...

As habitats modelling tools, and as their outputs are applied in a wide range of water management actions, key topics are the formulation of habitat requirements and the adaptability of a model for the specific objectives of the habitat study. In fact, the habitat output and its interpretation can be highly different whether we consider univariate...

The creation of lateral fish shelters has been pointed out as one of the most promising mitigation measures to protect fish species from artificial peak flows derived from hydropeaking operation of hydropower stations. However, little is known on how a fish shelter should be designed in order to optimize the habitat availability. The classical appr...

A rápida alteração dos caudais a jusante de centrais hidroeléctricas decorrente da produção de energia para satisfação de consumos de ponta é um dos factores que afectam as populações de peixes a jusante destes aproveitamentos. Este regime de funcionamento é referido na literatura anglo-saxónica por hydropeaking. Com a restituição do caudal turbina...

A modelação dos habitats piscícolas é hoje uma ferramenta largamente usada na gestão dos ecossistemas fluviais. Os modelos numéricos, na maioria bidimensionais, estão associados a um modelo biológico de habitat, que traduz as preferências de uma dada espécie por um determinado habitat. Estas preferências podem ser definidas em termos de curvas de p...

Hydropower energy is a renewable resource and the actual trend is to gain more and more importance following the population growth and the rise of global awareness to the climate change. Moreover, in order to store the surplus of electricity produced by windmills, more and more pumped storage schemes are being constructed. The respective powerplant...

Both water managers and researchers have the same goal when it comes to fish conservation, namely, to sustain, to improve or to restore aquatic habitat. To this aim, two-dimensional (2D) hydrodynamic models have been widely used in aquatic habitat studies because they simulate flow with high accuracy and can predict habitat dynamics. The River2D mo...

Fragmentation of freshwater systems is one of the more common human-induced impacts on the environment, and one of the most dramatic because it leads to disconnections among riverine habitats, severely affecting fish populations. To counter this form of ecological abuse, there has been a significant increase of the number of restoration actions. Th...

River ecosystems have witnessed a long history of human pressure, particularly the disruption of freshwater fish populations. The awareness of this situation has led to many habitat improvement projects, with a variable degree of success. In natural situations, fish populations co-inhabit throughout the hydrological cycle with different degrees of...

River ecosystems have witnessed a long history of human pressure, particularly Mediterranean rivers which are less resilient to perturbations, leading to the disruption of freshwater fish populations. To overcome this situation, many restoration projects have been implemented with varying degrees of success. In this dissertation, a two dimensional...

Os ecossistemas fluviais têm testemunhado uma longa história de pressão humana, resultado do aumento significativo do consumo de água e a diversificação das suas utilizações. A consciência desta situação levou à concepção e implementação de muitos projetos de requalificação fluvial, com um variável grau de sucesso. Em situações naturais, as espécie...

REQUALIFICATION PROGRAM OF THE ODELOUCA RIVER (ARADE BASIN, PORTUGAL). The construction of the Odelouca dam, located in a Nature 2000 area, has determined many compensation measures, such as the environmental requalification of the aquatic ecosystems in the river segment not submerged by the reservoir. We surveyed and identified the more disturbed...