Extreme Discharge Research Articles

Rainfall–Runoff in Conterminous Tropical River Basins of Southwestern Nigeria

ABSTRACT Frequency analysis of extreme events is used to evaluate the probable maximum flood from runoff records using probability distribution functions. This study aims to understand rainfall-runoff relationships in four conterminous basins in Southwestern Nigeria using the runs test, Pearson correlation, and wavelet coherence. The study revealed that the highest Extreme Annual Rainfall in the series is expected to occur once every 31 years with 0.03 probability. Wavelet coherence shows a strong significant association with phases between Yewa – Ikeja and Yewa – Abeokuta. The observed extreme discharge values constitute the basis for establishing exceedance probabilities for the stations and their recurrence intervals.

Geomorphic impacts of Hurricane Florence on the lower Neuse River: Portents and particulars

In September 2018 Hurricane Florence had severe impacts on the lower Neuse River and Neuse estuary, North Carolina, despite the fact that it was a minor storm in terms of traditional indicators of storm intensity. The storm was consistent with recent trends and predictions of tropical cyclone activity driven by Anthropocene climate warming. However, its impacts in the Neuse area were also conditioned by idiosyncratic aspects of the geographic setting and the synoptic situation. Geomorphic changes examined here include erosion of estuarine shoreline bluffs, geomorphic transformations of small freshwater swamps, and effects on the river and floodplain upstream of the estuary. The shoreline changes caused by Florence were unique with respect to previous tropical cyclones and ongoing episodic erosion, due to the extraordinarily high and unusually long duration of storm surge. Transformations of the “ravine swamps”—mainly associated with deposition of >0.6 m of sand on organic muck and open water surfaces—were similarly unprecedented. Despite high river discharges (third highest on record) and the high storm surge, fluvial impacts in the lower river and fluvial-estuarine transition zone were minimal. This is attributable to the morphology of the channel-floodplain system, adapted to Holocene sea-level rise and preserved by wetlands protection programs. The large area of the storm, slow forward movement, and extreme rainfall of Florence are likely indicative of a “new normal” with respect to tropical cyclones in the region. However, the geomorphic impacts in the lower Neuse were largely determined by particulars of the Neuse estuary and Florence's storm track. An exception is the limited impacts on the lower fluvial portion of the river and the fluvial-estuarine transition zone, where there exists a complex mosaic of channels and flowing wetlands capable of accommodating extreme discharges.

Sensitivity of Estuaries to Compound Flooding

Fluvial and surge-tide extremes can occur synchronously resulting in compound flooding in estuaries, greatly intensifying the hazard. This flood risk has the potential to increase in the future as the frequency, phasing and/or intensity of these drivers change. Improved understanding of how extreme fluvial discharge and surge-tides interact will help inform future flood mitigation methodology. In this paper, therefore, we resolve for the first time intra-estuary sensitivities to fluvial and surge-tide extremes, for two contrasting UK estuaries (Humber and Dyfi). Model simulations at hyper-spatial resolution (< 50 m) using a 2D hydrodynamic model predicted compound flooding hazards based on: (1) present-day extreme events (worst on record); (2) present-day extreme events with shifted timings of the drivers to maximise flooding; and (3) modified drivers representing projected climate change. We found that in a small estuary with short-duration, high-intensity fluvial inputs (Dyfi), flood extent is sensitive to the relative timing of the fluvial and surge-tide drivers. In contrast, the relative timing of these drivers did not affect flooding in a larger estuary with a slower fluvial response to rainfall (Humber). In the Humber, extreme fluvial inputs during a compound hazard actually reduced maximum water depths in the outer estuary, compared with a surge-tide-only event. Projected future changes in these drivers by 2100 will increase compound flooding hazards: simulated sea-level rise scenarios predicted substantial and widespread flooding in both estuaries. However, projected increases in surge-tide behaved differently to sea-level rise of the same magnitude, resulting in a greater seawater influx and more flooding. Increased fluvial volumes were the weakest driver of estuarine flooding. In this paper we show how these interactions are complex and how the hydrodynamics vary considerably between different estuaries and sites within estuaries, making it difficult to generalise, use probabilistic or use 1D approaches for assessing compound flooding hazards. Hence, we contribute new knowledge and methods for catchment-to-coast impact modelling used for flood mitigation strategies.

A climatology of sub-seasonal temporal clustering of extreme precipitation in Switzerland and its links to extreme discharge

Abstract. The successive occurrence of extreme precipitation events on sub-seasonal timescales can lead to large precipitation accumulations and extreme river discharge. In this study, we analyze the sub-seasonal clustering of precipitation extremes in Switzerland and its link to the occurrence and duration of extreme river discharge. We take a statistical approach based on Ripley's K function to characterize the significance of the clustering for each season separately. Temporal clustering of precipitation extremes exhibits a distinct spatiotemporal pattern. It occurs primarily on the northern side of the Alps in winter and on their southern side in fall. Cluster periods notably account for 10 %–16 % of seasonal precipitation in these two regions. The occurrence of a cluster of precipitation extremes generally increases the likelihood and duration of high-discharge events compared to non-clustered precipitation extremes, particularly at low elevations. It is less true in winter, when the magnitude of precipitation extremes is generally lower and much of the precipitation falls as snow. In fall, however, temporal clusters associated with large precipitation accumulations over the southern Alps are found to be almost systematically followed by extreme discharge.

Self-pulsing discharge in hollow cathode simulated by a fluid model

A fluid model without an external circuit is used in simulating self-pulses in hollow cathode discharge under a He-Ar gas at 10 Torr. The average discharge current increases with anode potential, and three types of self-pulsing discharge modes are obtained: (a) regular self-pulse, (b) low amplitude self-pulse, and (c) damped oscillating pulses modes. The temporal and spatial distributions of plasma parameters in the self-pulsing discharge mode are studied. Results show that the electron density, electric potential, electric field, total net electron production rates integrated over the entire discharge cell and net positive charge density change periodically in a self-pulsing period. Self-pulsing frequency ranges from tens of kHz to more than 100 kHz, and increases linearly with the average discharge current approximately. In the present average discharge current range, the peak value and current amplitude of pulsing current increases and then decreases with the increasing average current, whereas the minimum pulsing current consistently increases. The change trend of extreme self-pulsing discharge current is consistent with the change trends of total net electron production rate and net positive charge density in the discharge space. Finally, the mechanism of self-pulse in a hollow cathode discharge is proposed. Simulated results show that the phases of different plasma parameters are different in different discharge regions in a self-pulsing period. Non-equilibrium fluctuation of plasma parameters in different discharge regions is one of important factors in the formation of self-pulse. Self-pulse does not depend on an external circuit and originates from the internal microcosmic mechanism of discharge: the enhancement and weakening of the positive charge layer.

Short-term river mouth bar development during extreme river discharge events: The role of the phase difference between the peak discharge and the tidal level

This paper addresses the role of the phase difference between the peak discharge and the tidal level on the development of nearshore bars at river mouths during extreme river discharge events. We use a coupled hydrodynamic and morphodynamic numerical model (Delft3D) to reproduce extreme river discharge events on an idealized river mouth debouching on a nearshore shelf, characterized by a concave cross-shore profile. Different peak river discharges and lags between the peak discharge at the upstream boundary and the high tide at the offshore boundary are tested. The analysis of the water levels, currents, bed shear stresses, sediment transport rates and bed level changes shows that the lag between tidal conditions and river discharge triggers significant changes in (1) the instant in which the maximum currents at the outlet are reached, (2) the period for which the sediment is mobilized through the outlet, and (3) the maximum sediment transport rates during the events. These changes significantly modify the final characteristics of the river mouth bars, doubling their final extension and quadrupling the final bar volume for the same river discharge conditions and different phase lag, varying also their plan shape and the development of lateral subaqueous levees. These results emphasize the complex interplay between river and coastal hydrodynamics, being of major interest for researchers and managers dealing with projections of the consequences of coastal extreme events and plans to mitigate their effects.

Integrated modeling analysis of estuarine responses to extreme hydrological events and sea-level rise

Estuaries are vulnerable to climate change and are particularly sensitive to extreme river discharge (RD) and sea-level rise (SLR). To understand the effects of extreme RD and SLR on estuaries, an integrated modeling approach is adopted to simulate hydrodynamic changes in the Yangtze River Estuary. Model results showed that SLR will intensify the estuarine hydrodynamics in water level, currents, and salinity. Water level, current speed, and salinity increased linearly with the magnitude of SLR. The hydrological model suggested a lower RD in the future. This will increase the saltwater intrusion, which will be more severe during the lower RD and drought extreme hydrological event (EHE) conditions. Model results also suggested that the saltwater intrusion is more sensitive to RD than SLR. In addition, the interplay between the RD and SLR will exacerbate the impacts of coastal oceans on estuarine hydrodynamics, especially during extremely low RD conditions. Moreover, the decrease of RD and deepening of the channel due to human activities will also amplify the effects of SLR on the Estuary, increasing the risk of coastal disasters.

Compound Flooding: Dependence at Sub-daily Scales Between Extreme Storm Surge and Fluvial Flow

Estuaries are potentially exposed to compound flooding where weather-driven extreme sea levels can occur synchronously with extreme fluvial discharge to amplify the hazard. The likelihood of compound flooding is difficult to determine due to multiple interacting physical processes operating at sub-daily scales, and poor observation records within estuaries with which to determine potential future probabilistic scenarios. We hypothesize that fluvial extremes can occur within the peak of the surge in small/steep catchments because of rapid runoff times, whilst the length-scale in larger/flatter catchments will result in fluvial and marine extremes being out-of-phase. Data (15 min river flow and hourly sea level) spanning 40 years were analyzed to assesses the behaviour and timings of fluvial and sea level extremes in two contrasting estuaries: Humber and Dyfi (United Kingdom). Compound events were common in the Dyfi, a small/steep catchment on Britain’s west coast with fast fluvial response times. Almost half of the 937 skew-surge events (95th-percentile) occurred within a few hours of an extreme fluvial peak, suggesting that flood risk is sensitive to the storm timing relative to high tide—especially since flows persisted above the 95th-percentile typically for less than 12 h. Compound events were more frequent during autumn/winter than spring/summer. For the Humber, a larger/flatter catchment on the east coast with slower fluvial response times, extreme fluvial and skew-surge peaks were less frequent (half as many as the Dyfi) and compound events were less common (15% of events co-occurred). Although flows in the Humber persisted above the 95th-percentile for typically between one and 4 days, hence overlapping several high tides and possibly other surges. Analysis of 56 flooding events across both estuaries revealed: 1) flooding is more common in the Dyfi than Humber; 2) Dyfi flooding is driven by 99th-percentile flows lasting hours and co-occurring with a 95th percentile skew-surge; 3) Humber flooding was driven by 95th-percentile flows lasting days, or surge-driven—but rarely co-occurring. Our results suggest that compound flooding studies require at least hourly data (previous analyses have often used daily-means), especially for smaller systems and considering the potential intensification of rainfall patterns into the future.

The dendrogeomorphic use of shrubs for the detection of landslide movements: A case study of Corylus avellana L.

Dendrogeomorphic-based landslide activity dating is a commonly employed scientific approach used to detect historical landslide events with subannual precision. Trees are dominantly used for this research, but in some localities, current dendrogeomorphic methods are not suitable due to their exclusive occupation by shrub species. Nevertheless, shrub species have recently been successfully used in dendroclimatic research. Thus, this study aims to evaluate the applicability of common shrub species in Europe (Corylus avellana L.) in dendrogeomorphic research on landslides. In total, 71 stem samples from 11 shrub groups were macroscopically and microscopically analysed. Nearly half of the samples provided evidence supporting the presence of tension wood as a response to stem tilting due to landslide movement. The intensity of tension wood expressed by changes in vessel lumen area corresponded to the intensity of stem tilting, but no relationship was found for ring eccentricity. Moreover, the eccentricity of rings was found to be inapplicable to landslide event detection due to the short length of the studied C. avellana ring series. Nevertheless, the analysis of tension wood provided evidence of two past landslide events (2010 and 2014) and the absence of chronological noise. Moreover, the onset of tension wood was very abrupt, enabling the dating of landslide movements with seasonal precision. This assumption was verified by an analysis of potential triggers: extreme precipitation and high river discharge. Moreover, the roots of C. avellana exposed during the triggering flood undercutting the landslide base expressed a similar anatomical response to exposure, as seen in the cases of broad-leaved tree species. The results of this study could distinctly extend the use of dendrogeomorphic analysis of landslides into regions with no tree vegetation.

CLINICAL ASSESSMENT OF A LOCAL APPLICATION OF KASISADI GHRITAIN PARIKARTIKA (FISSURE-IN-ANO)

Parikartika is charecterised by sharp cutting pain in the anal region. In parikartika teevrashoola, bleeding is observed, equally extreme pain slimy blood discharge are seen in fissure-in-ano. To test the efficacy of thelocal application of kasisadi ghruta in managing. Classical signs and symptoms of parikartika (fissure in ano) age groups of 20 to 60 years have been recruited for the research. The trial group obtained treatment with kasisadi ghruta local application for 28 days, twice a day. Average relief observed was observed 62.5% for most symptoms shothahara, vedanasthapana, and ropana are in kasisadi ghruta. Properties because of which it helps in healing the ano fissure.

Managing floodplains using nature‐based solutions to support multiple ecosystem functions and services

AbstractFloodplains include unique environments shaped over a long time horizon along rivers and smaller streams and formed by alluvial sediments. As floodplains are flat, often with highly fertile and well‐accessible land, they have become the intrinsic focus of human society—while providing a variety of goods and ecosystem services. Intensive land use of floodplains is degrading their natural values and significantly reducing their ecosystem functions and services. A significant part of these key services is related with the ability of floodplains to retain water and nutrients, which can be understood as a flood control and a water‐retention function. Although these ecosystems serve a number of other basic functions, the importance of floodplains as a place for water retention during extreme discharges caused by intense rainfall or snowmelt and the supply of water in times of drought are essential under conditions of global change. In order to increase the ability of floodplains to perform these functions, it is increasingly required to preserve the connectivity of rivers with surrounding floodplains and adapt human activities to maintain and restore river ecosystems. This article reviews the recent understanding of floodplain delineation, the most common causes of disturbance, the ecosystem functions being performed, discussing in turn the measures being considered to mitigate the frequency and magnitude of hydrologic extremes resulting from ongoing environmental changes.This article is categorized under: Water and Life &gt; Conservation, Management, and Awareness Engineering Water &gt; Planning Water

INTEGRATING DIGITAL ELEVATION MODEL, LANDUSE/LANDCOVER AND FLOOD FREQUENCY ANALYSIS: A DETERMINISTIC APPROACH TO FLOOD INUNDATION AND RISK MODELING OF MAKURDI ALONG ITS RIVER BENUE REACH

The study applied GIS techniques to integrate Digital Elevation Model (DEM), Landuse/Landcover (LULC) and flood frequency analyses to determine extent of flood hazard inundation of Makurdi town along its River Benue reach following extreme discharges and stage levels. Annual maximum stage and discharge data from 1914 to 2015 was analyzed using Gumbel’s distribution to predict flood flow for different return periods (T): 5, 10, 25, 50, 75, and 100. A goodness of fit test was conducted using Chi square statistics, which was insignificant indicating that River Benue at Makurdi flood flow fits the Gumbel distribution. Combining this result with DEM and classified LULC data, the GIS spatial analyst tool was used to estimate the areal extent of landuse that will be inundated per return period. The result shows extent of flood inundation based on current landuse pattern for the respective return periods of predicted extreme stage / discharge likely due to climate change to be as follows: bareland (1.69, 1.74, 1.78, 1.84, 1.83, 1.89 km2); settlement/built-up (5.38, 5.50, 5.63, 5.76, 5.76, 6.02 km2); farmlands (272.27, 283.59, 295.10, 306.43, 306.43,and 317.49 km2); Vegetation (91.56, 95.26, 98.78, 102.45, 102.48, and 105.95 km2); water bodies (0.21,0.21, 0.22,0.22,0.22, and 0.22 km2) and Wetlands (44.14, 45.80, 47.48, 30.36,49.42 and 50.78 km2). This reveals a general increase in the extent of flood inundation at progressive recurrence interval, and predicted rising extreme river stage heights / discharge except for the flood with 50 year recurrence interval. The study recommends that NEMA and Benue State Urban Development Board

Anthropogenic climate change has changed frequency of past flood during 2010-2013

The ongoing increases in anthropogenic radiative forcing have changed the global water cycle and are expected to lead to more intense precipitation extremes and associated floods. However, given the limitations of observations and model simulations, evidence of the impact of anthropogenic climate change on past extreme river discharge is scarce. Here, a large ensemble numerical simulation revealed that 64% (14 of 22 events) of floods analyzed during 2010-2013 were affected by anthropogenic climate change. Four flood events in Asia, Europe, and South America were enhanced within the 90% likelihood range. Of eight snow-induced floods analyzed, three were enhanced and four events were suppressed, indicating that the effects of climate change are more likely to be seen in the snow-induced floods. A global-scale analysis of flood frequency revealed that anthropogenic climate change enhanced the occurrence of floods during 2010-2013 in wide area of northern Eurasia, part of northwestern India, and central Africa, while suppressing the occurrence of floods in part of northeastern Eurasia, southern Africa, central to eastern North America and South America. Since the changes in the occurrence of flooding are the results of several hydrological processes, such as snow melt and changes in seasonal and extreme precipitation, and because a climate change signal is often not detectable from limited observation records, large ensemble discharge simulation provides insights into anthropogenic effects on past fluvial floods.

Numerical optimization of the cooling effect of the bionic spider-web channel cold plate on a pouch lithium-ion battery

For lithium-ion battery thermal management system for electric vehicles, the insertion of metal plates with channels on both sides of a lithium-ion battery is an effective method for a high-temperature cooling. Inspired by the nature spider-web structure, we propose a cold plate with a bionic spider-web channel inside. Based on the heat generation characteristics of the pouch lithium-ion battery at an extreme discharge rate of 12 C, we used an orthogonal experimental design to study the cooling performance of the spider web-channel structure for a lithium-ion battery. Numerical simulation results showed that, among the structural parameters of the spider-web channel, the channel width had the largest influence on the cooling performance of the cold plate, while the channel angle had the smallest influence. The increase in the channel width could not indefinitely enhance the cooling performance of the cold plate. The most suitable structure was obtained at a width of 3 mm. When the channel angle was 120°, the pouch lithium-ion battery could provide the best thermal balance.

The Coupling Effect of Flood Discharge and Storm Surge on Extreme Flood Stages: A Case Study in the Pearl River Delta, South China

The low-lying Pearl River Delta in South China is subject to severe flood threats due to watershed floods, sea level rise, and storm surges. It is still unknown to what extent and how far inland storm surges and sea level rise impact the extreme flood stages. This study investigated the coupling effect of flood discharge and storm surge on the extreme flood stages in the Pearl River Delta by using on site observations and simulations generated by the Hydrologic Engineering Center-River Analysis System model. The results show that flood discharges dominated the flood stages in the middle and upper Pearl River Delta, while the storm surges had maximum impact near the river mouth. The storm surges and flood stages showed a significant increase after 2002 in the Hengmen waterway. The design flood stages for the post-2002 period were 0.23–0.89 m higher than the pre-2002 ones at Hengmen at the six return periods from 5 to 200 years examined in this study. Their difference declined toward the upper waterway and reduced to zero about 23 km away from the Hengmen outlet. The coincidence of extreme flood discharges and storm surges further escalates the extreme flood stages in the lower 30 km of estuarine waterways. Our results quantify the severe threats due to sea level rise and intensified storm surges in the lower Pearl River Delta, and are significant for urban planning and designing and managing flood control facilities in the Pearl River Delta and in other coastal fluvial deltas.

Extreme wire electrical discharge machining based on semiconductor characteristics

To meet the increasing demand for wire electrical discharge machining (WEDM) under extreme conditions such as ultra-high thickness cutting, micro-wire cutting, micro-energy finishing, and ceramic composites machining, a concept of multichannel discharge WEDM under semiconductor characteristics was proposed. The essence of this conception is that under these extreme machining conditions, the electrode wire or workpiece — or even both of the two electrodes — cannot be treated as electrically conductive materials of the conventional WEDM due to their high electrical resistance. However, they can exhibit electrical discharge behavior like semiconductors, which is defined as semiconductor characteristics. The conventional WEDM theory and related technologies cannot be applied to extreme WEDM because conventional WEDM only has one discharge channel per pulse, whereas multiple discharge channels can be generated by each pulse in extreme WEDM. Therefore, a suitable theory needs to be developed for extreme WEDM under semiconductor characteristics. Based on the multichannel discharge behavior of semiconductors, experiments were conducted on high-efficiency machining with multichannel discharge by stacking several workpieces as an assembly with semiconductor characteristics. It was proved that the multichannel discharge WEDM is capable of achieving high machining efficiency, as well as enhanced surface quality and lower wear of electrode wire. The proposed multichannel discharge WEDM sets up the foundation for the establishment of the theoretical system of EDM under semiconductor characteristics.

Chromophoric dissolved organic matter (CDOM) in a subtropical estuary (Galveston Bay, USA) and the impact of Hurricane Harvey.

The landfall of Hurricane Harvey in August 2017 provided the opportunity to study the impact of extreme freshwater discharge on chromophoric dissolved organic matter (CDOM) properties in a subtropical estuary (Galveston Bay, Texas). Both fluorescence spectroscopy (excitation-emission matrices) and a three-component parallel factor analysis (PARAFAC) model identified changes in CDOM properties. Comparing to Coble's peaks, component 1 was similar to peak C, component 2 to peak M, and component 3 to peak B. Results clearly show three periods with distinct CDOM properties: a dry season, a wet season, and Hurricane Harvey. The dry season was characterized by higher values of the spectral slope and fluorescence and biological indices. The wet season was characterized by high values of PARAFAC components 1 and 2 (humic-like) and the absorption coefficient at 350 nm. Some CDOM components were highly correlated with salinity, indicating conservative mixing. Component 3 (protein-like) had a low correlation to salinity, suggesting degradation or production processes in the bay. Silicates and NO3- + NO2- had negative relationships with salinity and a positive one with PARAFAC components 1 and 2. PARAFAC component 3 was correlated with dissolved oxygen and chlorophyll a, suggesting a relationship between CDOM fluorescent components and phytoplankton activity. High values of the humification index were observed immediately after Hurricane Harvey, indicating increased input of terrestrial organic matter into the bay. Hurricane Harvey increased CDOM levels and humification, and the variability and changes seem to be mostly due to freshwater discharge from the San Jacinto River and not the Trinity River. The influx of freshwater was sufficient to eliminate the salinity gradient in Galveston Bay and significantly change CDOM properties. Galveston Bay recovered quickly from the hurricane and associated flux of freshwater, returning to pre-hurricane CDOM characteristics in less than 2 months.

Response of boreal clay soil properties and erosion to ten years of no-till management

We compared soil physical, chemical and biological properties, erosion rate and carbon allocation to soil physical fractions between conventional tillage (CT) and no-till (NT) management at a clay soil site under spring cereal monoculture in southwestern Finland. Subsurface drain discharge, surface runoff and soil erosion were continuously monitored in 2008 − 2018. At the end of the 10-year monitoring period in 2018, various soil properties and earthworm total density, mass and species richness were determined. Total soil erosion was 56 % less in NT than in CT although surface water discharge was higher in NT. NT had a clear effect on the topsoil physical structure by decreasing the pore size and increasing soil aggregate size. The total soil carbon stock in the 700 kg m−2 mineral topsoil layer (approx. 0−60 cm layer) was slightly lower in NT (108 ± 12 Mg C ha-1) than in CT (118 ± 9.0 Mg C ha-1) due to lower carbon content of the 10−30 cm layer in NT. In NT the proportion of large macroaggregates was higher and more organic carbon was bound to large macroaggregates in the 0−10 cm layer which may be related to the higher abundance of earthworms in NT. The results showed that NT is an effective method to reduce erosion rates but other means to increase carbon input especially below the topsoil layer are likely required to achieve a significant increase in the carbon stock of boreal clay soils. For both tillage managements, the rate of erosion through subsurface drains depended clearly on annual precipitation and winter temperature, posing a challenge in the future climate with mild winters and more extreme discharges.

Experimental study of a novel strategy to construct the battery thermal management module by using tubular phase change material units

For the thermal management of cylindrical power battery module, the classical cuboid-like phase change material (PCM) module still remains problematic, because the bulky structure remarkably decreases the energy density and secondary heat-dissipation capability of the battery module. Here a novel strategy to construct the PCM module was proposed by substituting the bulky cuboid PCM module with tubular PCM units. Compared to the classical cuboid module, the assembled tubular PCM module confers numerous naturally-formed channels for air flow, an enlarged outer surface area for secondary heat dissipation, and a greatly reduced module weight. As a result, the tubular PCM module demonstrates a superior heat-dissipation performance for cylindrical power batteries. For example, with forced air convection, the temperature and temperature difference can be controlled below 47.2 and 1.0 °C respectively under an extreme working environment, i.e., 10 charge and discharge cycles at a high environment temperature of 40 °C. More importantly, this novel strategy also benefits the flexible assembling and maintenance of the modules, and saves 54% of the PCM amount, thus increasing the energy density of the battery module from 75.5 to 94.4 Wh kg−1.

What evidence exists on the impacts of flow variability on fish and macroinvertebrates of temperate floodplain rivers in Central and Western Europe? A systematic map protocol

BackgroundFlow variability is considered a fundamental factor affecting riverine biota. Any alterations to flow regime can influence freshwater organisms, and this process is expected to change with the projected climate change. This systematic map, therefore, aims at investigating the impacts of natural (resulting from climatic variability), anthropogenic (resulting from direct human pressure), and climate change-induced flow variability on fish and macroinvertebrates of temperate floodplain rivers in Central and Western Europe. Particular focus will be placed on the effects of extreme low and high discharges. These rare events are known to regulate population size and taxonomic diversity.MethodsAll studies investigating the effects of flow variability on metrics concerning freshwater fish and macroinvertebrates will be considered in the map, particularly metrics such as: abundance, density, diversity, growth, migration, recruitment, reproduction, survival, or their substitutes, such as biomonitoring indices. Relevant flow variability will reflect (1) anthropogenic causes: dams, reservoirs, hydroelectric facilities, locks, levees, water abstraction, water diversion, land-use changes, road culverts; (2) natural causes: floods, droughts, seasonal changes; or (3) climate change. Geographically, the map will cover the ecoregion of Central and Western Europe, focusing on its major habitat type, namely “temperate floodplain rivers and wetlands”. The review will employ search engines and specialist websites, and cover primary and grey literature. No date, language, or document type restrictions will be applied in the search strategy. We expect the results to be primarily in English, although evidence (meeting all eligibility criteria) from other languages within the study area will also be included. We will also contact relevant stakeholders and announce an open call for additional information. Eligibility screening will be conducted at two levels: title and abstract, and full text. From eligible studies the following information will be extracted: the cause of flow variability, location, type of study, outcomes, etc. A searchable database containing extracted data will be developed and provided as supplementary material to the map report. The final narrative will describe the quantity and key characteristics of the available evidence, and identify knowledge gaps and knowledge clusters, i.e. subtopics sufficiently covered by existing studies allowing full systematic review and meta-analysis.