River Modification Research Articles

In need of improvement: archaeological evidence of river management in South-Eastern Australia

AbstractPatterns of river modification since settler invasion of southern Australia are the product of a specific set of deep-seated and implicit cultural values concerning the purpose and function of waterways. Rivers have been dammed, diverted, dredged and straightened to meet a range of human needs and objectives. Such changes are routinely described as ‘improvements’ but there is a lack of critical engagement with what ‘improvement’ might mean. Interventions carried out initially on an ad hoc basis, and later more systematically with state support, collectively shed light on the persistent underlying drive to ‘Improve’ nature and society that has permeated Western thought since the Enlightenment. Here we use the example of one river system, the Loddon, to analyse ways in which Improvement intersected with settler engagement with Australian rivers. We argue that settler interventions have been informed by a consistent set of understandings about the purpose of rivers. The characteristics of water management infrastructure along the Loddon reveal how the river fell short of the settler-colonial ideal and why they thought it needed to be Improved at all.

Full floodplain connectivity: Realising opportunities for ‘Stage 0’ river restoration

AbstractContinued declines in freshwater biodiversity and the challenges of climate change are creating greater interest in river restoration projects. Increasing recognition of the interaction between biological, geomorphological and hydrological processes has led to the development of ‘Stage 0’ river restoration. Stage 0 reaches are typically multi‐thread anabranching systems connected to the floodplain and its ecosystems. It is suggested that the defining characteristic of Stage 0 conditions is that of connectivity (longitudinal, lateral and vertical) at base flows. The methods or mechanisms that can re‐create such reaches are described, namely valley floor reset, beaver activity, beaver dam analogues and the use of large wood in the channel and floodplain. The scope for wider adoption of Stage 0 is then discussed and recommendations for expanding this approach across temperate regions with a long history of river modification and higher population densities are presented.

Characterising mine wastes as archaeological landscapes

AbstractIndustrial‐scale metal mining has long been a feature of developing economies. Processing ores to recover minerals has generated large quantities of waste rock, tailings and contaminants. Mining‐related deposits, along with associated soil and water geochemistry, river modifications and other environmental changes, are a product of the nature, scale and intensity of past operations. These artefacts of historical mining create anthropogenic landscapes that extend far beyond individual sites due to the dispersal of mine waste by rivers and pose enduring threats to human and ecosystem health. Their presence and significance, however, are often overlooked by heritage and environmental managers. To be acknowledged as artefacts of the historical mining industry, landscape features must be identified and characterised with reference to the human activities that triggered their formation. This requires an interdisciplinary approach that incorporates anthropogenic landscape change at a regional scale. In this paper, we integrate archaeological, geomorphological and geochemical evidence to identify and analyse mining‐related changes to the Loddon River valley in Victoria, Australia. Nineteenth‐century gold mining caused extensive erosion of creeks and gullies and mobilised sediments that filled channels and spread over floodplains. In addition, tailing deposits concentrated arsenic at levels significantly above environmental background conditions. Recognising these legacies of historical mining is vital to understanding mining heritage and to managing healthy rivers, environments and communities.

Global Observations of Riverbank Erosion and Accretion From Landsat Imagery

AbstractRiverbank migration has historically been seen as a risk to infrastructure that can be combated through channelization, bank stabilization, and sediment trapping. The physical processes involved with riverbank erosion and deposition are well defined, yet the solutions to equations that describe these processes are computationally and data intensive over large domains. While current understanding of large‐scale river channel mobility largely comes from reach‐ and watershed‐scale observations, we need global observations of riverbank erosion and accretion to broaden our understanding of sediment processes within and across river basins. In this work, we create the first global data set of riverbank erosion for >370,000 km of large rivers using up to 20 years of water classifications from Landsat imagery. We estimate uncertainty by propagating water classification errors through our methods. Globally, we find riverbank erosion for rivers wider than 150 m to have an approximately log‐normal distribution with a median value of 1.52 m/yr. Comparing our data set to 25 similar estimates of riverbank migration, we found a normalized mean absolute error of 42% and a bias of 5.8%. We show that river width is the best first‐order predictor of riverbank erosion, in agreement with existing literature. We also show that the relationship between width and bank erosion is substantially different among a sample of global river basins and suggest that this is due to second‐order influences of geology, hydrology, and human influence. These data will help improve models of sediment transport, support models of bank erosion, and improve our understanding of human modification of rivers.

Evaluation of Biogeochemical Changes in Channelized and Restored Portions of a Subtropical Floodplain

Floodplains are critically important ecosystems that provide a whole suite of ecosystem services, including nutrient and carbon sequestration, flood mitigation, water storage, and critical wildlife habitat. However, human modification of rivers and floodplains through channelization, artificial levee construction, reductions in the active floodplain area, and water management can significantly reduce the ecosystem function of river–floodplain systems. In this study, we evaluated the changes in the nutrient loading of the Kissimmee River floodplain during the restoration of the river–floodplain system. In addition to time-series loading analysis, we also evaluated soil nutrient concentrations across the lower portion of the Kissimmee River floodplain. During the 44-year nutrient loading time-series, the floodplain remained a nutrient exporter with changes in nutrient loading generally corresponding to both water quality (i.e., point source reductions) and hydrologic restoration activities in the watershed and Kissimmee River floodplain. During the study period, inputs of total phosphorus and total nitrogen loads from upstream either significantly increased or remained the same. In addition to external sources of nutrients, internal sources of nutrients from floodplain soils can also contribute to the total nutrient export from the system. These internal sources could be organic via the decomposition of organic matter or geologic from the original excavation of the canal and/or restoration backfilling. Soil nutrient concentrations vary between vegetative communities and landscape position and could be a significant source of phosphorus to the downstream system, which is plagued by eutrophic conditions. Therefore, as floodplain function in the Kissimmee River continues to be restored and managed, additional effort may be needed to address nutrient inputs and internal legacy nutrients.

Effect of Urban River Morphology on the Structure of Macroinvertebrate Communities in a Subtropical Urban River

Channelization is the most common hydraulic modification of urban rivers. Here, we assessed the effects of urban river morphology on benthic communities by analyzing the characteristics of benthic communities at various sites in channelized and natural rivers of the Longgang River system in southern China. We detected four Clitellata species, five Oligochaeta species, one Polychaeta species, 10 Gastropoda genera/species, two Bivalvia genera/species, two Crustacea genera/species, and 14 Insecta genera/species. Insecta and Oligochaeta were the dominant classes in the wet and dry seasons, and Chironomus plumosus was the most dominant species. The density of Clitellata was significantly lower in channelized rivers (0–0.74 ind/m2) than in natural rivers (0.61–4.85 ind/m2). The Shannon’s diversity index was significantly lower in channelized rivers (0.66–1.04) than in natural rivers (0.83–1.28) in the wet and dry season. NH3.N was positively correlated with Shannon’s diversity index, and chemical oxygen demand and river width were negatively correlated with Shannon’s diversity index. When the concentration of total phosphorus (TP) was low (<3 mg/L), it was positively correlated with Shannon’s diversity index. Our findings indicate that river channel morphology affects benthic faunal structure and diversity, but the effects varied among seasons. Minimized channelization will prevent the loss of aquatic biodiversity in subtropical urban rivers, as will preservation of natural rivers.

The response of a brown trout (Salmo trutta) population to reintroduced Eurasian beaver (Castor fiber) habitat modification

Globally, freshwaters are the most degraded and threatened of all ecosystems. In northern temperate regions, beaver (Castor spp.) reintroductions are increasingly used as a low-cost and self-sustaining means to restore river corridors. River modifications by beavers can increase availability of suitable habitat for fish, including salmonids. This study investigated the response of a population of brown trout (Salmo trutta) to reintroduced Eurasian beaver (Castor fiber) habitat modifications in northern Scotland. The field site comprised two streams entering a common loch; one modified by beavers, the other unaltered. Electrofishing and PIT telemetry surveys indicated abundance of post-young-of-the-year (post-YOY) trout was higher in the modified stream. Considering juvenile year groups (YOY and post-YOY) combined, abundance and density varied with year and season. In the modified stream, fork length and mass were greater, there was a greater variety of age classes, and mean growth was positive during all seasons. Beavers had profound effects on the local brown trout population that promoted higher abundances of larger size classes. This study provides important insight into the possible future effect of beavers on freshwater ecosystems.

Narratives underlying research in African river basin management

River modifications through hydropower dams and other infrastructure have far-reaching economic, ecological and social effects that are viewed in highly contrasting ways depending on underlying narratives. As part of a Euro-African research consortium funded by the European Commission we studied pathways for sustainable river basin management in the Omo-Turkana basins in Ethiopia and Kenya. Based on a literature review, stakeholder workshops, targeted interviews and considering our own positionality, we identified underlying narratives related to (a) economic transformation and modernization, (b) indigenous rights and (c) nature conservation, which were all connected through water, energy, food and ecosystems within a (d) landscape nexus. Yet, we also identified a (e) living museum narrative suggesting that international advocacy for indigenous rights and nature conservation is a means through which Western societies want to preserve African societies in an “undeveloped” state. National governments use this narrative to silence external critique, while the tourism industry promotes it to advertise visits to pastoralist tribes. This narrative reveals powerful, yet largely ignored hindrances for collaborative projects resulting from cultural and historical biases in Euro-African collaborations. Based on our analysis, we argue that international research projects in sustainability sciences need to increase the transparency of open and hidden narratives that influence research directions and power relationships between scientific partners, also those using mostly technically-driven approaches. We emphasize that African landscapes are not to be viewed as living museums, and collaborative research should be based on fairness, respect, care, and honesty to allow for multiple narratives that underlie research.

Response of fish assemblages to restoration of rapids habitat in a Great Lakes connecting channel

Rapids habitats are critical spawning and nursery grounds for multiple Laurentian Great Lakes fishes of ecological importance such as lake sturgeon, walleye, and salmonids. However, river modifications have destroyed important rapids habitat in connecting channels by modifying flow profiles and removing large quantities of cobble and gravel that are preferred spawning substrates of several fish species. The conversion of rapids habitat to slow moving waters has altered fish assemblages and decreased the spawning success of lithophilic species. The St. Marys River is a Great Lakes connecting channel in which the majority of rapids habitat has been lost. However, rapids habitat was restored at the Little Rapids in 2016 to recover important spawning habitat in this river. During the restoration, flow and substrate were recovered to rapids habitat. We sampled the fish community (pre- and post-restoration), focusing on age-0 fishes in order to characterize the response of the fish assemblage to the restoration, particularly for species of importance (e.g. lake whitefish, walleye, Atlantic salmon). Following restoration, we observed a 40% increase in age-0 fish catch per unit effort, increased presence of rare species, and a shift in assemblage structure of age-0 fishes (higher relative abundance of Salmonidae, Cottidae, and Gasterosteidae). We also observed a “transition” period in 2017, in which the assemblage was markedly different from the pre- and post-restoration assemblages and was dominated by Catostomidae. Responses from target species were mixed, with increased Atlantic salmon abundance, first documented presence of walleye and no presence of lake sturgeon or Coregoninae.

Genetic diversity patterns in Phragmites australis populations in straightened and in natural river sites in Lithuania

Like in many other parts of the world, Phragmites australis distribution and abundance are changing in Lithuania because of the impact of human activities on aquatic habitats. We studied P. australis genetic diversity patterns and the effect of hydrographic modifications, introduced in the mid-late twentieth century with great impact on Lithuanian landscape. The genetic diversity was studied using chloroplast DNA sequences and nuclear microsatellite markers in natural and straightened river stretches for water regulation. We found haplotypes M and L and their variants in the studied populations. The analysis of microsatellites revealed high genetic diversity within populations and significant structure both at the population and river level. We did not find differences in the distribution of genetic diversity between populations growing in natural and in straightened river stretches; however, at the local level, 5 populations in straightened river sites had higher genetic diversity values than populations in nearby natural sites within the same river, confirming seed establishment in disturbed habitats. Our results demonstrate that anthropogenic river modifications have had an impact on the genetic diversity of P. australis populations; however, disturbance is not the only factor that affects genetic diversity recruitment and dynamics in new P. australis stands.

The Case for Studying Highly Modified Agricultural Streams: Farming for Biogeochemical Insights

AbstractA significant fraction of Earth's land surface is used for agriculture, which has led to extensive modification and degradation of streams and rivers. Although highly modified, agricultural streams offer important opportunities for advancing our understanding of agroecosystems and applying the principles of translational ecology. Using examples from the upper midwestern U.S., we discuss how highly modified agricultural streams can be used to gain insights into ecological and biogeochemical processes, though often this involves adjusting the paradigms and approaches used to study streams in less disturbed landscapes. We argue that highly modified agricultural streams could serve as a model for how less disturbed systems might respond to ongoing and future environmental change. Last, these streams often are targets for restoration, which opens the door to engaging with diverse stakeholders, including policymakers and nontraditional funding sources such as philanthropic foundations and industry groups.

Ecological Guidelines and Recommendations for Mula-Mutha Riverfront Development

This paper is a case of urban river Mutha for ecological management.Over the past few decades, condition of river Mutha has deteriorated considerably. The present situation shows less of fresh water flow and lot of sewage water addition,waste dumping and foul smelling water flow. The fresh water contribution by base flow to the main stream is very negligible. The only source of fresh water is sporadic water release from Khadakwasala dam. It is irregular and in small proportion to support ecosystem functioning of the river Mutha.There is a of public debate regarding improvement in the river's condition and to correct its root cause. The disruption in the river's ecosystem is basically by human interventions. The study appeals for interdisciplinary approach with a view of environmental governance and management to solve river related problems. The focus of this study is to assess environmental impact when the river related projects being planned by Municipal authorities. The study included survey of physical changes by human interventions, in the river Mutha channel ,banks and modification of habitats hampering aquatic as well as land biodiversity. The study indicated crucial biodiversity indicators for the health of the river ecosystem. By giving grades based on both the physical conditions and biodiversity of various stretches of the river plan to improve conditions is suggested.The study created guidelines for restoration and management of Mutha river ecosystem, which may be useful for rivers especially in the urban area. This paper is based on the research project .Ecological Guidelines and Recommendations for Mula-Mutha Riverfront Development. conducted by Ecological Society.

Site-specific and seasonal variation in habitat use of Eurasian otters ( Lutralutra) in western China: implications for conservation.

As a top predator, the Eurasian otter (Lutra lutra) is an indicator of healthy freshwater ecosystems and a flagship species for conservation. Once widespread in China, the species is now distributed mainly in the upper reaches of the great rivers of western China. However, a lack of knowledge on local otter populations continues to hinder their conservation in China. Here, we conducted a detailed study on habitat use of Eurasian otters in Yushu City and Tangjiahe National Nature Reserve in western China using transect surveys. At both study sites, otters preferred to defecate on large rocks close to or protruding from the river and about 50 cm above the waterline. In Yushu, no spraints were found along the 5 km river bank section in the downtown area, with otters preferring sprainting sites with natural banks, riparian zones, and lower human population density. However, this pattern was not obvious at Tangjiahe, where river transformation and human disturbance are minor. Otter river use intensity was negatively correlated with elevation and human population density in Yushu in both seasons. In Tangjiahe, otter river use intensity was positively correlated with prey mass and flow rate and negatively correlated with human population in spring, but positively correlated with human population and negatively correlated with flow rate in autumn. These results reflect the flexible habitat use strategies of otters at different sites, underlining the necessity to study otters living in different regions and habitat types. We provide suggestions for river modification and call for more site-specific studies to promote otter conservation in China.

Do ecosystem insecurity and social vulnerability lead to failure of water security?

Achieving water security for humans and ecosystems is a pervasive challenge globally. Extensive areas of the Americas are at significant risk of water insecurity, resulting from global-change processes coupled with regional and local impacts. Drought, flooding, and water quality challenges pose significant threats, while at the same time, rapid urban expansion, competing water demands, river modifications, and expanding global markets for water-intensive agricultural products drive water insecurity. This paper takes a social-ecological systems perspective, aiming to identify examples and pathways towards resilient ecosystems and social development. It draws on lessons from two science-policy network projects, one focusing on water scarcity in arid and semi-arid regions of Argentina, Chile, Brazil, Peru, Mexico and the United States; and the second addressing river and lake basins as sentinels of climate variability and human effects on water quantity and quality in Canada, the United States, Argentina, Colombia, Uruguay and Chile. Together, these ‘complementary contrasts’ provide an analytical basis to empirically examine stakeholder engagement, knowledge co-production and science-policy interaction supporting decision-making to achieve water security. The paper identifies four tenets for decision-making based on water-security-focused global-change science in the Americas: 1) Decision makers should focus on protecting ecosystems because water security (along with food and energy security) depend on them; 2) Water-use and allocation decisions ought to be made considering future environmental and societal vulnerabilities, especially climate projections; 3) Holistic approaches (at basin or other appropriate levels) are best suited to ensure social-ecological system resilience and reduce vulnerability; and 4) It is essential to support local/traditional livelihoods, and underserved populations to achieve equitable water security and ecosystem resilience.

Overview of past, current, and future ecosystem and biodiversity trends of inland saline lakes of Europe and Central Asia

ABSTRACT This review of trends in inland saline lakes of Europe and Central Asia is based on the relevant section of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) Regional Assessment Report for Europe and Central Asia (ECA). We assessed the present status of ECA saline lakes and the effects of direct drivers (climate change, land use, pollution, resource exploitation, invasive species) on ecosystem health and biodiversity. We also assessed past, current and future trends using habitat area and degradation, species richness, and endangered species as indicators. No uniform scenario is applicable to saline lakes in the region. The desiccation of the Aral Sea is caused mainly by land use change and water extraction. In the Caspian Sea, river modifications, water pollution, overfishing and poaching, and species invasions have led to a decrease in species richness and have threatened endemic species. Although trends for smaller saline lakes vary, our analysis demonstrates that land use change, over-exploitation, and pollution are more important direct drivers of ecosystem health and biodiversity than climate change. The establishment of baseline biodiversity values for saline lakes is, however, complicated because biodiversity and the food-web structure are variable and depend strongly on salinity. Thus, there is a need to classify the ecological quality, biodiversity and ecosystem services of saline lakes along a salinity gradient. The improvement of water management and reuse of water, conservation measures, and introduction of climate-smart agriculture are basic conditions for the sustainable use of saline lakes in the region.

Catfish Population Characteristics among River Segments with Altered Fluvial Geomorphic Conditions in the Missouri River, Nebraska, USA

AbstractAlteration of river systems around the world has created novel environments that have been fragmented, homogenized, or transformed from their natural state, thus posing challenges for understanding how fish populations function. The Missouri River has undergone significant alteration through reservoir construction and channelization. Channel Catfish Ictalurus punctatus and Flathead Catfish Pylodictis olivaris both reside in various fragmented sections of the river, and there is a substantial gap in knowledge of how catfishes synchronously function in this modified system. From 2009 to 2018, we assessed catfishes with baited hoop nets and low‐frequency electrofishing among four different areas: upper and lower unchannelized segments and upper and lower channelized segments. Differences in population demographics and dynamics occurred for both species among segments. Both the highest and lowest relative abundances for Channel Catfish occurred in channelized segments, and Flathead Catfish relative abundance was lowest in both unchannelized segments. Subadult growth rates for both catfish species were greater in channelized segments. Channel Catfish mortality was highest in channelized segments, which was consistent with the maximum ages found in channelized (age 9) versus unchannelized (age 15) segments. High‐flow events in 2010 and 2011 led to an increase in recruitment, but populations declined in subsequent years. This long‐term assessment revealed spatial and temporal differences in population dynamics among varying levels of anthropogenic alteration. Our study illustrates how river modification and extreme climatological events may impact and structure catfish populations. These data provide a basis for assessing catfish throughout the Missouri River system and offer insight into how catfish populations in other altered large‐river systems might function.

Relationships of otter populations with fish, macroinvertebrates and water quality across three Korean rivers revealed by inferential modelling based on evolutionary computation

Depending on the life cycles of trophic biota, cascades of biological transition are established between top-down and bottom-up relationship. In South Korea, flows of the large rivers have been regulated with large weirs and estuary barrages construction. The Eurasian otter Lutra lutra is a semi-aquatic carnivore and top predator in freshwater systems. In order to understand the aquatic community variability under the impact of river modifications, we assessed the strengths of otter populations in relation to limnological data monitored between 2014 and 2016 at 250 sites of the Nakdong River, 92 sites of the Yeongsan River and 81 sites of the Seumjin River. The habitat preference and resource use of otter populations have been measured for each of the 423 river sites by the number of spraint (= otters' feces) per 600 m. The limnological data included water quality parameters, abundances of Mollusca, Anthropoda, Annelida, Nematomorpha, and Platyhelminthes as well as abundances of benthivore, herbivore, planktivore and piscivore fish. The hybrid evolutionary algorithm HEA has been applied to model relationships of otter with water quality, the benthic invertebrates and fish to determine habitat and food preferences of otter across the three rivers.Despite the stochastic noise of the data, the modelling results addressed well relationships between spraint densities and densities of fish and macroinvertebrate communities. Threshold conditions of the IF-THEN-ELSE-models discovered by HEA revealed otter responses to changing habitats and aquatic communities across the river sites but also between the three rivers. In addition, sensitivity analysis suggested possible relationships between the otter and aquatic communities. According to the results of sensitivity analysis, otter populations seemed not to control the piscivorous fish densities by showing a negative relationship, but preyed preferably on benthivorous and planktivorous fishes. Water quality parameters and benthic macro-invertebrates correlated well with otter populations suggesting favorable habitat and food-web structures. There is evidence that river flow regulation measures have a negative impact on otter populations, and that growing otter populations will alter future food web structures of the three rivers.

A comprehensive assessment of stream fragmentation in Great Britain

Artificial barriers are one of the main threats to river ecosystems, resulting in habitat fragmentation and loss of connectivity. Yet, the abundance and distribution of most artificial barriers, excluding high-head dams, is poorly documented. We provide a comprehensive assessment of the distribution and typology of artificial barriers in Great Britain, and estimate for the first time the extent of river fragmentation. To this end, barrier data were compiled from existing databases and were ground-truthed by field surveys in England, Scotland and Wales to derive a correction factor for barrier density across Great Britain. Field surveys indicate that existing barrier databases underestimate barrier density by 68%, particularly in the case of low-head structures (<1 m) which are often missing from current records. Field-corrected barrier density estimates ranged from 0.48 barriers/km in Scotland to 0.63 barriers/km in Wales, and 0.75 barriers/km in England. Corresponding estimates of stream fragmentation by weirs and dams only, measured as mean barrier-free length, were 12.30 km in Scotland, 6.68 km in Wales and 5.29 km in England, suggesting the extent of river modification differs between regions. Our study indicates that 97% of the river network in Great Britain is fragmented and <1% of the catchments are free of artificial barriers.

Pluridisciplinary analysis and multi-archive reconstruction of paleofloods: Societal demand, challenges and progress

Abstract Floods are one of the gravest natural hazards for societies, worsened by population growth, unchecked development, and climate change. From a Global Change perspective, past extreme events merit particular interest because they can be linked to wider climate and environmental changes, introduce perturbations. During the last decade, knowledge of long-term flood frequency and magnitude has been improved by extracting data from different types of archive. But, despite advances in dating methods, proxies and statistical techniques and efforts to identify atmospheric drivers, some fundamental questions remain unresolved. The Special Issue entitled “Pluridisciplinary analysis and multi-archive reconstruction of paleofloods” in the journal Global and Planetary Change addresses these uncertainties and complexities by assembling a selection of studies, which were first presented at the Past Climate Changes (PAGES) Open Scientific Meeting held at Zaragoza in 2017. In this introductory paper, the guest editors outline the 17 research contributions and meta-data from the 17 paleoflood studies were systematically analyzed in terms of i) geographical distribution; ii) methodologies applied; iii) types of archives; iii) numbers of flood series compiled and iv) spatial and temporal resolution of paleoflood data. The data indicate that paleoflood studies focused on fluvial depositional environments show a higher rate of integration with other types of paleoflood archive (mean of 4.5 types of archive) than studies focused on documentary sources (mean of 3.5) and lake sediments (mean of 2.4). We suggest that this strategy of archive integration has been adapted to effectively compensate for the higher uncertainties of fluvial deposition in floodplains. Statistical processing of the meta-data shows quantitative associations between specific types of flood archive and offers a solid platform for designing the optimal approach for multi-archive paleoflood research. A qualitative review and visual comparison of the 17 paleoflood series shows some consistent trends and breaks but also notable differences within and between regions. While a trend of increased flooding since 4-5 ka BP is evident, the lack of synchronicity between breaks and the coeval increases and decreases in fluvial activity is manifest. The majority of studies in the Special Issue do denote the 19th century – including the youngest cool climate pulses during the Little Ice Age – as a particularly flood-rich period. It is more difficult to assess the 20th century because of social changes, population growth and extensive river modification. Despite the mentioned uncertainties, 10 of 14 papers do not record the 20th century as an exceptional flood period. Assessing the effects of human impact on paleoflood calendars and disentangling anthropogenic from natural drivers are major challenges in integrated paleoflood analysis. It is concluded that the interpretation of flood series is complex as landscapes and flood drivers are heterogeneous and systems show different sensitivities to flood control and drivers. Thus, the study of past floods, from historical and natural archives, is challenging but also offers unparalleled opportunities to document low-frequency, large-magnitude flood events, which occurred under a broad range of climate and/or environmental scenarios, and, probably, the only way to reconstruct robust paleoflood series.

Learning from Rivers

Learning from Rivers