Dense macrophyte beds are known to produce extreme diurnal oxygen and temperature conditions in shallow lakes. However their influences in managed hydropeaking reservoirs has received limited attention. We measured dissolved oxygen, pH and water temperature in the Lake Karāpiro hydroreservoir, northern New Zealand, across a gradient of proportional water‐column height occupied by the invasive macrophytes

Riparian vegetation survival and establishment in gravel‐bed rivers depends on the balance between vegetation growth and flood disturbance. We present four examples of vegetation and landform development in gaps (linear open spaces) between established islands and/or floodplain within a reach of the middle Tagliamento River, Italy. Gaps offer shelter to vegetation, supporting higher colonization success

This paper describes changes in bed morpho‐dynamics and topography in the River Ehen, a regulated river in NW England (i.e., temperate climate) following a rehabilitation project that reconnected a formerly diverted headwater sub‐catchment back to its main‐stem. Sediment grain‐size distributions in the Ehen changed subtly and in rather complex ways following the reconnection. Changes were most evident

This paper is the first of a pair that report the findings of a river rehabilitation project centred on the reconnection of a formerly diverted headwater tributary (Ben Gill) to its main‐stem river (the River Ehen). The present paper describes the geomorphic evolution of the tributary in the 2 years following its reconnection, with a particular focus on assessing the volumes of sediment now being supplied

Fishways have traditionally been designed according to the capabilities of salmonids, but other species may be unable to navigate such structures. To improve passage for the entire local fish fauna in a cost‐effective manner, pool‐and‐weir fishways can be reconstructed to a hybrid vertical slot design. Here, we contrast a typical short‐term before‐after monitoring approach with a long term data series

Turbidity, an index of light side‐scattering, depends on the mass concentration of suspended sediment (SS) within water. Turbidity of river water is regulated by the presence of suspended particulate matter and is used to identify visual changes in response to SS. We used data from the New Zealand National River Water Quality Network, to calculate “specific turbidity” (K ; turbidity normalised to mass

How should the success of river and floodplain restoration be assessed? What should we be restoring? We contend that the benchmark for restoration should be the river in its “natural,” that is, quasi‐equilibrium condition prior to deliberate modification. The pre‐modification condition of the river represents a quasi‐equilibrium state in which the river accommodates and adjusts to catchment water and

The migration corridors in regulated rivers lead downstream fish migrants, particularly juveniles to pass through water infrastructure. Accelerating flow, experienced by fish, might trigger avoidance behaviour and then influence the downstream migration efficacy. It is essential to understand the causes of avoidance behaviour exhibited by downstream migratory fish in accelerating flow. In this study

Perennial streams and rivers are now largely subjected to fragmentation and lentification processes due to flow reduction, which creates a number of lateral habitats with different degrees of hydrological connectivity. These habitats have environmental conditions and biotic interactions that can be far divergent than those of main channel habitats. However, they remain largely unexplored, especially

Hydropower development is accelerating in the tropics, especially construction of small dams. Small dams are often classified as those lower than 15 m in height or with reservoir capacity less than 3 × 106 m3. Small dams frequently operate with water diversions from the main river channel, thereby affecting river connectivity through the creation of a dewatered reach. However, the extent and impact

Several superhigh dams (greater than 200 m in height) and many high dams have been built in the upper Yangtze River basin in recent years, and these dams have made total dissolved gas (TDG) supersaturation a serious environmental problem. A few studies have examined the tolerance and avoidance characteristics of rare and endemic fish in TDG‐supersaturated water in the upper Yangtze River over the past

During downstream passage at hydroelectric facilities, fish can be injured when exposed to rapid decompression; this is especially of concern when passing through turbines. The rapid decrease in pressure can cause barotrauma, as undissolved gas expands according to Boyle's law. However, it is difficult to see barotrauma occurring within the body of the fish in real time. In order to determine if transparent

Dams, road crossings, and water withdrawals extensively fragment rivers, and watersheds often contain hundreds or thousands of barriers, some of which no longer meet societal purposes. Accordingly, both conservationists and infrastructure managers are faced with the challenge of prioritizing barriers for repair, replacement, or removal. Candidate projects have been prioritized with dozens of methods

Rivers are dynamic, complex integrators of their environment, which makes verification of the beneficial outcomes of restoration challenging. Thermal regime is central to habitat suitability and is often a focus in planning and evaluating the impact of restoration and climate resilience. Among these concerns, high summer stream temperature has frequently been identified as a limiting factor for salmon

Riparian vegetation does not only affect the channel flow carrying capacity, but also plays significant roles in water management, stream restoration, and river rehabilitation. This study numerically investigates the flow characteristics through longitudinally discontinuous rigid vegetation occupying half width of the channel, with the help of three‐dimensional software FLUENT in which a Reynolds stress

Assessments of river condition are needed to guide all aspects of river management. Such assessments have evolved over three decades from simply capturing the mosaic of river physical habitats to recognizing that habitat mosaics are dynamic, driven mainly by physical processes and modified by human (indirect) pressures and (direct) interventions. To embrace these broader aspects, riparian as well as

The typical Japanese river maintains a vegetation‐suppressive effect on riparian habitats. During recent decades, most Japanese rivers have encountered extensive human‐induced alterations, and over time, the rivers have been transformed from unvegetated to vegetated. The lower Tedori River, which is a representative case of this phenomenon, is located in a region that exhibits signs of global climate

Physical habitat is crucial for structuring local fish assemblages. Understanding habitat structure is important for fish management and conservation. Herein, we assessed whether sonar‐derived substrate data could explain spatial variation in species‐catch rates. Using a side‐scan sonar, we mapped the substrates of two non‐wadeable rivers in Illinois, USA and conducted standardized fish surveys at

The space–time dynamics and the effect of urban growth on territory transformation were simulated with Iber 2D to analyze flooding events in the lower basin of the Sabinal River, Mexico. We classified the main coverages and land uses of the study area. Soil roughness and water infiltration in the soil were evaluated. Both values were used as input data in a simulation model with Iber 2D to analyze

Reservoirs are ecosystems that provide important services and reserves of aquatic biodiversity, especially in arid and semiarid regions. However, they are also highly vulnerable to pollution, water abstraction and land use change. Here, we aimed to develop a “dirty‐water” predictive model that could be used to create recovery scenarios and analyze the effect of measures on the biological quality of

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 how river management and restoration activities have

Rivers and floodplains provide many regulating, provisioning and cultural ecosystem services (ES) such as flood risk regulation, crop production or recreation. Intensive use of resources such as hydropower production, construction of detention basins and intensive agriculture substantially change ecosystems and may affect their capacity to provide ES. Legal frameworks such as the European Water Framework

Harmful algal blooms are occurring in large river ecosystems and at the mouth of large rivers with increasing frequency. In lentic systems, the chemical and physical conditions that promote harmful algal blooms are somewhat predictable but tracking prevalence and conditions that promote harmful algal blooms in lotic systems is much more difficult. We captured two of the most extreme discharge years

Following a review of the European distribution, habitat requirements and life history characteristics of two riparian tree species, Alnus incana (L.) Moench (grey alder, a member of the Betulaceae family) and Populus nigra L. (black poplar, a member of the Salicaceae family), we explore their changing spatial distribution and topographic position within a 7 km, island braided reach of the Tagliamento

Runoff simulation is highly significant for hydrological monitoring, flood peak simulation, water resource management, and basin protection. Runoff simulation by distributed hydrological models, such as the soil and water assessment tool (SWAT) model which is the most widely used, is becoming a hotspot for hydrological forecasting research. However, parameter calibration is inefficient and inaccurate

On August 2017, a massive rock slope failure triggered an extreme sedimentation event in a regulated Alpine river. Consequently, high sediment load affected the river for about 1 month, with sediment concentration peaking up to several hundred g/L, and overall sediment yield of 0.4–0.8 Mm3. The availability of sound pre‐event data concerning benthic macroinvertebrate assemblages gave us the opportunity

Aquatic ecosystem response to dam construction and operation is an important concern, but systematic assessment of impacts induced by cascade small rubber dams are seriously lacking. In this study, the Huangshui River in Qinghai Province was selected to investigate biological response to small cascade rubber dams. Two years of monitoring data in 2018 and 2019 were utilized to quantify the variation

The entrainment of fish in irrigation canals has long been a management concern in western North America. In north‐central Montana, United States, the presumed but unexamined entrainment of the “threatened” bull trout (Salvelinus confluentus Suckley) in the St. Mary Canal was considered a major impediment to the species' Federal Endangered Species Act recovery. Between April and September, 2002–2006

The present study investigated the effects of clay content and levee's slopes on the breach formation process for levees constructed by both cohesive and non‐cohesive soils. Twelve experiments were carried out and the breach formation of levees was observed by measuring the breach discharge variations and scour topography with time. The initiation of surface erosion was analysed by comparing the estimated

River floodplains are hotspots of productivity and biodiversity and recognized to fulfil vital ecosystem functions and services. Restoration measures of the decoupled Danube floodplains east of Vienna aim to re‐establish multi‐functionality, that is, ensure navigation, preserve and restore unique fluvial and riparian habitats and re‐establish natural processes and service provisioning. Side‐channels

Seines are a common sampling gear for monitoring small‐bodied fishes in wadeable, sand‐bed rivers. However, sampling effort within a site can vary among time and space, even within the same monitoring program. Determining and standardizing an adequate or optimal amount of effort within a site is an important step for designing fisheries monitoring programs. If budgets are limited, sampling intensity

In addition to the well‐known biotic response to hydropeaking, the occurrence of ice, its interrelation with hydropeaking and possible mitigation are still poorly investigated. The goal of this study was to determine the impacts of hydropeaking on ice formation and the design of possible mitigation measures in the cold Mongolian climate. The study was conducted for the Eg hydropower plant, which is

Understanding the trophic discrimination (∆13C and ∆15N) between consumers and diets in fluvial systems remains difficult because of the variable food sources and complex predator–prey interactions from headwaters to the estuaries. Here, stable carbon (δ 13C) and nitrogen (δ 15N) isotopes in fish and invertebrates from a large subtropical river in southern China were determined to explore trophic discrimination

Streams and their adjacent riparian zones are increasingly viewed as interdependent systems linked by reciprocal exchanges of energy, organisms, and materials. We assessed potential associations between the emerging aquatic insect flux and transitions between agricultural land and forest fragments to better understand these stream‐riparian linkages in managed landscapes. We sampled stream environmental

Agricultural intensification has resulted in severe declines in the extent and diversity of seminatural habitats in Europe, whereas the extent of secondary habitats has increased considerably. River embankments have become one of the most extensive and widespread secondary habitats in former floodplains. We compared the diversity patterns of secondary dry and wet grasslands on river embankments with

We conducted flume experiments to study the morphological behaviour around a circular pier located downstream of a mining pit. Severe transverse erosion at the pier base as well as lowering of channel bed upstream of the pier was observed because of channel dredging. Streambed instability was analysed based on two non‐dimensional parameters, namely, pier exposure factor and normalized upstream incision

Damming of streams and rivers alters downstream ecosystem processes, and understanding its effects is essential in managing forested mountain streams. This study examined the effects of dams with a reservoir on organic matter decomposition and its seasonality in two neighbouring mountain streams over five seasons. The cotton‐strip assay and measurement of tensile strength loss were used to evaluate

The accelerating climate crisis intensifies environmental changes in high‐altitude ecosystems worldwide, with rising air temperature among the main stressors. While past research in alpine streams has primarily focused on how retreating glaciers might affect the ecology of glacier‐fed streams on the long run, observations of real‐time alterations of water temperature in such pristine environments are

Riverine fish populations depend on habitats supporting their resource and life history needs. Dynamic streamflow caused by river regulation or natural events influences the distribution of downstream habitat characteristics. Through studying habitat selection, we can identify the most utilized and valuable habitats for the success of native fishes. We determined seasonal habitat selection of two common

As rivers warm, cold‐water fish species may alleviate thermal stress by moving into localized thermal refuges such as cold‐water plumes created by cool tributary inflows. We quantified use of two tributary confluence plumes by juvenile steelhead, Oncorhynchus mykiss, throughout the summer, including how trout positioned themselves in relation to temperature within confluence plumes. At two confluences

Microhabitat selection models are frequently used in rivers to evaluate anthropogenic effects on aquatic organisms. Fish models are generally developed from few rivers, with debatable statistical treatments for coping with overdispersed abundance distributions. Analyses of data from multiple rivers are needed to test their transferability and increase their relevance for stakeholders. Using 3,528 microhabitats

Although there is increasing consensus that river restoration should focus on restoring processes rather than form, proven techniques to design and monitor projects for sediment transport processes are lacking. This study monitors bedload transport and channel morphology in a rural, an urban unrestored, and an urban restored reach. Objectives are to compare bedload transport regimes, assess the stability

Lacking substantial erosive and sedimentation forces, regulated rivers allow their floodplains to become overgrown with forest, increasing the flood risk of the hinterland. In the Netherlands, floodplains have therefore been subjected to interventions, like clear cutting, lowering and creation of side channels, and management, consisting of grazing and mowing. However, the comprehension of how those

Peaking hydroelectric facilities release water from dams to match energy production with demand, often on a daily cycle. These fluctuating flows downstream can exert several potential stressors on organisms that may inhibit their growth, indirectly causing higher contaminant concentrations through reduced growth dilution. We collected spottail shiner (Notropis hudsonius) at two sites upstream and two

The Chinese mitten crab is one of the top invasive species in Europe. In Flanders (Belgium), they are associated with river ecosystem degradation, especially the loss of aquatic vegetation and associated ecosystem services. Management measures have therefore been put in place to reduce the number of crabs migrating between the sea and freshwater areas and ultimately control the population. Although

Aichi Prefecture, which has a dense industrial area, is one of the sites in Japan where the levels of zinc are elevated. However, currently, there is no clear evidence of the source of zinc in this prefecture. This study aims to assess zinc concentration and load in a river and identify the main sources of zinc pollution. We conducted a 20‐month survey to identify the temporal and spatial variation

Spatial information on the distribution of ecosystem patterns and processes can be a critical component of designing and implementing effective management programs in river‐floodplain ecosystems. For example, translating how flood pulses detected within a stream gauge record are spatially manifested across a river‐valley bottom can be used to evaluate whether the current distribution of physical conditions

River water management is challenging not only since they are open systems with changing physical structures, but also because the water values are mostly unknown over varied sectors. If policymakers grasp water values, water management will be more efficient. This research intends to examine the values of water in agriculture, which receives the most substantial portion of water resources, with the

Connectivity of nurseries and spawning habitats for young of the year life stage is essential for successful recruitment of fish populations and therefore provides a key indicator for river restoration measures. Models for dispersal offer the potential to draw conclusions regarding restoration scenarios and to fill knowledge gaps about possible implications for fish populations. A newly developed rheoreaction‐based

Dam construction and operation are known to alter the hydrology of rivers and degrade riverine ecosystems. In recent decades, the call to reverse these negative impacts by re‐operating dams has become stronger. Dams can support riverine ecosystems by releasing environmental flows (e‐flows). Unfortunately, despite the development of numerous methodologies to determine e‐flows and optimise dam releases

To understand the spatiotemporal variation characteristics and the sources of water pollutants in the Shayinghe River Basin, water quality monitoring data of the five water quality indexes (biochemical oxygen demand: BOD5, permanganate index: CODMn, ammonium nitrogen: NH3–N, total phosphorus: TP and dissolved oxygen: DO) were collected from 11 monitoring stations and divided into 6 categories (classes

Adaptive management is central to improving outcomes of environmental water delivery. The Australian Government's Murray−Darling Basin (MDB) Plan 2012 explicitly states that adaptive management should be applied in the planning, prioritisation and use of environmental water. A Long Term Intervention Monitoring (LTIM) program was established in 2014 to evaluate responses to environmental water delivery

Placement of wood in streams has become a common method to increase ecological value in river and stream restoration and is widely used in natural environments. Water managers, however, are often hesitant to introduce wood in channels that drain agricultural and urban areas because of backwater effect concerns. This study aims to better understand the dependence of wood‐induced backwater effects on

Sustainable transboundary water governance is often challenged by conflicts between agents, which necessitates the design of cooperative and self‐enforcing alternatives to facilitate equitable water distribution. A pervasive and critical problem related to many transboundary rivers is that the total allocation or demand of riparian states is usually much more than that of the total available water

Northward flowing rivers are the most vulnerable system to a general early warming trend in terms of flood risk. In a changing climate, how well we understand the variability of precipitation and streamflow and the correspondence between them determines the appropriateness and efficiency of river engineering activities, flood control structures, and water resource management policies. Using both time

A perfect storm refers to an event in which a rare combination of circumstances significantly exacerbates the event. River science faces a potential perfect storm through the emergence of several factors. First, pronounced and persistent human modifications to catchments and rivers have resulted in regime shifts—a state change of riverine landscapes. Anthropocene Rivers have different ecosystem structures

Potadromous salmonids that reside in hydropower reservoirs often have a high recreational and conservation value. However, the potential seasonal turbine entrainment vulnerability patterns of potadromous salmonids are not well understood. Here, we use acoustic telemetry to test the hypothesis that adults of two species of the Salvelinus genus (bull trout and lake trout) differ in their seasonal patterns

Dams and reservoirs are known to disturb river‐water composition, among other impacts, with potential implications for downstream river ecosystems and water uses. Existing studies have emphasized the variable influence of dams on water composition according to the element, its speciation (dissolved vs. particulate), reservoir properties (residence times), reservoir functions (e.g., hydropower, irrigation)

Quantifying the downstream survival of migrating fish past dams is critical for conservation efforts. Regulators require assessments of survival as a condition of operation. Failure to meet an established survival standard may result in required operational or costly structural changes at a facility. Establishing the survival standard, as well as the rules of assessment, is a point of contention between

Fish assemblages in large rivers are governed by spatio‐temporal changes in habitat conditions, which must be accounted for when designing effective monitoring programmes. Using boat electrofishing surveys, this study contrasts species richness, catch per unit effort (CPUE), total biomass, and spatial distribution of fish species in the Saint John River, New Brunswick, Canada, sampled during different