Search

Across a 1000‐km stretch of the River Nile, from the 1st Cataract in southern Egypt to the 4th Cataract in Sudan, many hundreds of drystone walls are located within active channels, on seasonally inundated floodplains or in now‐dry Holocene palaeochannel belts. These walls (or river groynes) functioned as flood and flow control structures and are of a type now commonly in use worldwide. In the Nile Valley, the structures have been subject only to localised investigations, and none have been radiometrically dated. Some were built within living memory to trap nutrient‐rich Nile silts for agriculture, a practice already recorded in the early 19th century C.E. However, others situated within ancient palaeochannel belts indicate construction over much longer time frames. In this paper, we map the distribution of these river groynes using remote sensing and drone survey. We then establish their probable functions and a provisional chronology using ethnoarchaeological investigation and the ground survey, excavation and radiometric dating of the structures in northern Sudan, focusing on the Holocene riverine landscape surrounding the pharaonic settlement of Amara West (c. 1300–1000 B.C.E.). Finally, we consider the historical and economic implications of this form of hydraulic engineering in the Nile Valley over the past three millennia.

The Nile Basin drains about one-tenth of the African continent and contains the longest river channel system in the world. This chapter reviews the evolution of the river – with a particular focus on the Quaternary Period including the present-day hydrology and fluvial geomorphology. Fluctuations in the climate and hydrology of tropical Africa during the Quaternary exerted an important influence on the behaviour of the Nile sediment system. During the cold stages of the Pleistocene, low lake levels reflect a decrease in precipitation as the expanded ice sheets cooled the global oceans and monsoon intensity fell. The marine sedimentary record in the Eastern Mediterranean provides a valuable record of the long-term behaviour of the River Nile because long-term changes in the flux of water and sediment from various parts of the catchment have exerted an important influence on oceanographic and sedimentation dynamics. The chapter examines the contemporary suspended sediment budget of the delta complex.

The article examines the effectiveness of GIS-technologies in Kazakhstan for determining and clarifying hydrographic characteristics (e.g. catchment area, river length, location, lakes and reservoirs), the analysis of hydrological processes and phenomena, as well as the creation of a cartographic and attributive database of water bodies. Yesil River, the main waterway of the central and northern part of Kazakhstan, is one of the least hydro- logically studied catchments in the region. To address this research and information gap data was obtained from remote sensing and runoff depth based on the Kazhydromet network for the period 1945 to 2016. A topographic and river network map (1:1,000,000) of the Yesil River basin, including locations of gauging stations as well as depth and runoff coefficient maps were created using ArcGIS software. These maps provide a very useful tool for water resource management and economic policy decision making.

Bucket dredging to mine and extract gold and tin from rivers is a global industry that has had a range of negative effects on physical environments. These include the destruction of riparian soil profiles and structures, artificial channel straightening and loss of in-stream biodiversity. In this paper we evaluate the immediate effects and long-term consequences of bucket dredging on rivers in Victoria and New South Wales during the period 1900–1950. High quality historical sources on dredge mining are integrated with geospatial datasets, aerial imagery and geomorphological data to analyse the scale of the dredging industry, evidence for disturbance to river channels and floodplains and current land use in dredged areas. The study demonstrates that the environmental impact of dredging was altered but not reduced by anti-pollution regulations intended to control dredging. An assessment of river condition 70–100 years after dredge mining ceased indicates that floodplains and river channels continue to show the effects of dredging, including bank erosion, sediment slugs, compromised habitat and reduced agricultural productivity. These findings have significant implications for river and floodplain management.

People and water intersect in the movement of sediment downstream in rivers. Social processes and geomorphological processes become entangled as each system moves in ways that trigger corresponding responses from the other. Long-term dialectical relationships emerge that span multiple human generations. The power of sediment and water to change physical environments is in constant tension with the power of human actions informed by social, cultural, legal, economic and engineering imperatives. The Pacific Rim gold rushes that began in the mid-nineteenth century provide an opportunity to examine how the interplay of people, water and sediment unfolds over historic time. The mass discharge of mining sediment in California and Victoria that began over 150 years ago was a catastrophic human alteration of river systems. Subsequently, mining sediment has had a long and complex entanglement with society and rivers in both regions and continues to be an active agent in reshaping riparian environments. Mining sediments also have a toxic legacy as associated contaminants, including mercury and arsenic, that are discharged into waterways and dispersed in windblown dust. The changes to river systems caused by gold mining committed societies and rivers to new trajectories of mutual engagement. Anthropogenically induced sedimentation that resulted from mining is an issue that will continue to impact watersheds for generations to come.

Low- and middle-income countries in Southeast and East Asia face a range of challenges related to the rapid pace of urbanisation in the region, the scale of pollution, climate change, loss of ecosystem services and associated difficulties for ecological restoration. Possible pathways towards a more sustainable future lie in the applications of nature-based solutions (NBS). However, there is relatively little literature on the application of NBS in the region, particularly Southeast Asia. In this paper we address this gap by assessing the socio-ecological challenges to the application of NBS in the region – one of the most globally biodiverse. We first provide an overview and background on NBS and its underpinnings in biodiversity and ecosystem services. We then present a typology describing five unique challenges for the application of NBS in the region: (1) Characteristics of urbanisation; (2) Biophysical environmental and climatic context; (3) Environmental risks and challenges for restoration; (4) Human nature relationships and conflicts; and (5) Policy and governance context. Exploiting the opportunities through South-South and North-South collaboration to address the challenges of NBS in Southeast and East Asia needs to be a priority for government, planners and academics. Highlights Most research on Nature-Based Solutions (NBS) is in high income nations with low population growth rates and regulated urban planning.; Urban blue-green infrastructure is being degraded in low and middle-income Southeast and East Asian countries.; Applications of NBS in the region need to address the unique socio-ecological challenges.; We provide an overview of key knowledge gaps to support the implementation of NBS.

Professor Kenneth J. Gregory was a major contributor to fluvial palaeohydrologicalresearch. Beginning in the early 1980s, under his influence, rapid internationalgrowth of the discipline was accompanied by major advances in research methodsand techniques. Current research emphases include applications of quantitative modelling and meta-analysis; the correlation of fluvial events to other records,notably palaeolacustine records; and methods for application to diverse issues ofriver engineering and management. The international expansion and detailed analyses of fluvial palaeohydrology are exemplified by recent studies done in Fennoscandia, the Mediterranean region, India, Israel, Australia, Pacific humid islandarcs, and South America. Future developments will involve expanded work withother academic disciplines, such as archaeology, as well as applications to practical problems arising from future climatic change and related environmental hazards, particularly extremes. Remote sensing and high-resolution topography data and tools (e.g. LiDAR) will facilitate new discoveries of ancient exceptional flooding phenomena (megaflooding and superfloods) on Earth and on the palaeofluvial forms of Earth-like planets. New opportunities will also arise from the increased use of machine learning and artificial intelligence for analyses of big data., Time devoted to the preparation of this state-of-the-science review was supported by the institutions listed as author affiliations.

A joint Kazakh-British archaeological initiative undertook a survey and excavation of the city of Kuik-Mardan, one of the largest of the seventy or so known settlements in the Otrar oasis on the Syr-Darya river, Kazakhstan. Several complimentary field techniques were employed including unmanned aerial vehicle photomapping and an extensive programme of radiometric dating. The radiocarbon dates obtained are the first for any city in the oasis and allow more confident interpretations of the experience of the city to be ventured. Also undertaken was a geoarchaeological investigation of the surrounding irrigation and water supply canal system. Key results include its wholesale destruction during the 6th to 7th century and the form of the later occupation of the city.

Mobilisation of large volumes of bedrock, regolith and soil has long been a characteristic feature of metal mining. Prior to the 20th century this was most efficiently achieved through harnessing the motive power of water. Large-scale water use in mining produced waste sands, gravels and silts that were flushed downstream, triggering changes in stream and floodplain morphology and function. During the 19th century the shift from artisanal to industrialised mining resulted in a rapid increase in the scale and extent of environmental change. This paper presents results from a multi-disciplinary research program investigating the environmental effects of 19th-century gold mining on waterways in south-eastern Australia. Archaeological and geospatial landscape survey are combined with historical data modelling and geomorphological analysis to examine the extractive processes that produced sediment in headwater regions and how this influenced fluvial processes operating on downstream waterways and floodplains. Our case study of the Three Mile-Hodgson Creek system on the Ovens (Beechworth) goldfield in north-east Victoria indicates that miners mobilised up to 7.3 million m3 of sediment in this small catchment alone. Results of the research suggest that tailings dams and sludge channels in this catchment are important archaeological evidence for early attempts to manage industrial waste.

The Victorian gold rush began in 1851, resulting in massive demographic, land use, and social changes (Serle 1968). Rivers, during much of the gold mining history of Victoria, were used as a “free” resource, both to extract and process sediment. The effect on river systems around the state was catastrophic. A quarter of the length of the main streams was damaged. Even though the devastating environmental impact of Victorian gold mining was recognised at the time, it appears to have been forgotten today (Figure 1). This is despite extensive documentation of the number of mining operations, methods used, resultant environmental impacts and consequent legislation. The ARC discovery project “Rivers of gold” set up a multi-disciplinary team to try and reconstruct the historical development of mining across the state of Victoria, and to determine the legacy of this mining.

Global perspectives on the complexities of environmental change impacts associated with past and present human activity are needed for the food and water security challenges of the twenty-first century. This is especially true for rivers, for which the onset and persistence of a range in human activities, altering their function and form, have been temporally and spatially variable. Ancient civilisations, states and empires extended geographically to cover sub-continental areas where their river modifying activities became linked to regional Earth system stresses arising from climate and land use change. We present a new interpretative framework for characterising and classifying human impact on river systems, emphasising that this has taken place over decadal to millennial time periods on a sub-continental scale. This 16-element classification and documentation of different human transformations, including land management, urbanisation, industry and engineering activities, is used to explore anthropogenic channel and floodplain disruptions that have followed each other in different sequences in different places. It is significant that these inadvertent and deliberate human interventions have also taken place in parallel with contrasting climatic fluctuations that have been sub-continental in scale and varied in time. We assess the influence of the dominant modes of regional climate variability (monsoons, El Niño Southern Oscillation, Indian Ocean Dipole, North Atlantic Oscillation, Pacific Decadal Oscillation and Siberian High) on the speed and pattern of river system adjustment to anthropogenic perturbations. Some river civilisations have proved resilient to change given their adaptive management, while others have been overwhelmed by climate-related changes in river morphodynamics. We conclude that integrated socioeconomic, climatic and hydromorphological histories provide usefully instructive antecedents for sensibly managing, as they evolve, the even more serious coupled environmental stresses likely in the future.

Global plastic demand has led to a growing abundance of microplastics being detected across all environmental compartments. These microplastics pose a long-term health risk to ecosystems through accumulation, ingestion and leaching of chemicals. Knowledge of microplastics in river catchments has been limited due to their complexity, however as microplastics have a terrestrial origin, freshwater systems are considered to be a key pathway to other environments. They can transport microplastics to marine environments, act as temporary and long-term storage and aid degradation of larger plastics into smaller fragments that enter the aquatic system.As microplastics are linked to anthropogenic sources, much of the focus has been placed on urban and industrial areas, but in this study, we aim to assess a rural, agricultural catchment. River Witham catchment in Eastern England covers the area of 3,000km2 with a population of ~400,000. The river provides important drainage for the high-grade agricultural land in the fens and it discharges into the Wash, which is England’s largest nature reserve as well as an important area for shellfish aquaculture.This presentation will address the preliminary findings of this project by detailing the spatial variability of microplastics storage in riverbed sediments in an agricultural catchment. Data suggests that microplastic concentration could be as high in rural areas as it is in urban areas. The findings are expected to help improve the knowledge of microplastic contamination on a catchment level and to act as a basis for regional environmental protection.

The Aral Sea basin in Central Asia and its major rivers, the Amu Darya and Syr Darya, were the center of advanced river civilizations, and a principal hub of the Silk Roads over a period of more than 2,000 y. The region's decline has been traditionally attributed to the devastating Mongol invasion of the early-13th century CE. However, the role of changing hydroclimatic conditions on the development of these culturally influential potamic societies has not been the subject of modern geoarchaeological investigations. In this paper we report the findings of an interdisciplinary investigation of archaeological sites and associated irrigation canals of the Otrār oasis, a United Nations Educational, Scientific and Cultural Organization (UNESCO) World Heritage site located at the confluence of the Syr Darya and Arys rivers in southern Kazakhstan. This includes radiometric dating of irrigation canal abandonment and an investigation of Arys river channel dynamics. Major phases of fluvial aggradation, between the seventh and early ninth century CE and between 1350 and 1550 CE coincide with economic flourishing of the oasis, facilitated by wet climatic conditions and higher river flows that favored floodwater farming. Periods of abandonment of the irrigation network and cultural decline primarily correlate with fluvial entrenchment during periods of drought, instead of being related to destructive invasions. Therefore, it seems the great rivers of Central Asia were not just static "stage sets" for some of the turning points of world history, but in many instances, inadvertently or directly shaped the final outcomes and legacies of imperial ambitions in the region.

Continental-scale models of malaria climate suitability typically couple well-established temperature-response models with basic estimates of vector habitat availability using rainfall as a proxy. Here we show that across continental Africa, the estimated geographic range of climatic suitability for malaria transmission is more sensitive to the precipitation threshold than the thermal response curve applied. To address this problem we use downscaled daily climate predictions from seven GCMs to run a continental-scale hydrological model for a process-based representation of mosquito breeding habitat availability. A more complex pattern of malaria suitability emerges as water is routed through drainage networks and river corridors serve as year-round transmission foci. The estimated hydro-climatically suitable area for stable malaria transmission is smaller than previous models suggest and shows only a very small increase in state-of-the-art future climate scenarios. However, bigger geographical shifts are observed than with most rainfall threshold models and the pattern of that shift is very different when using a hydrological model to estimate surface water availability for vector breeding., Prior studies mapping climatologically suitable areas for malaria transmission have used relatively simple thresholds for precipitation. Here the authors show that when models incorporate hydrological processes a more complex pattern of malaria suitability emerges in Africa and future shifts in suitability are more pronounced.

Background The Barotse floodplains of the upper Zambezi River and its tributaries are a highly dynamic environment, with seasonal flooding and transhumance presenting a shifting mosaic of potential larval habitat and human and livestock blood meals for malaria vector mosquitoes. However, limited entomological surveillance has been undertaken to characterize the vector community in these floodplains and their environs. Such information is necessary as, despite substantial deployment of insecticide-treated nets (ITNs) and indoor residual spraying (IRS) against Anopheles vectors, malaria transmission persists across Barotseland in Zambia’s Western Province. Methods Geographically extensive larval surveys were undertaken in two health districts along 102 km of transects, at fine spatial resolution, during a dry season and following the peak of the successive wet season. Larvae were sampled within typical Anopheles flight range of human settlements and identified through genetic sequencing of cytochrome c oxidase I and internal transcribed spacer two regions of mitochondrial and nuclear DNA. This facilitated detailed comparison of taxon-specific abundance patterns between ecological zones differentiated by hydrological controls. Results An unexpected paucity of primary vectors was revealed, with An. gambiae s.l. and An. funestus representing < 2% of 995 sequenced anophelines. Potential secondary vectors predominated in the vector community, primarily An. coustani group species and An. squamosus. While the distribution of An. gambiae s.l. in the study area was highly clustered, secondary vector species were ubiquitous across the landscape in both dry and wet seasons, with some taxon-specific relationships between abundance and ecological zones by season. Conclusions The diversity of candidate vector species and their high relative abundance observed across diverse hydro-ecosystems indicate a highly adaptable transmission system, resilient to environmental variation and, potentially, interventions that target only part of the vector community. Larval survey results imply that residual transmission of malaria in Barotseland is being mediated predominantly by secondary vector species, whose known tendencies for crepuscular and outdoor biting renders them largely insensitive to prevalent vector control methods. Graphical Abstract

Rivers have played a defining role in the global development of human societies and culture. This will undoubtedly continue in the twenty-first century with a growing demand for water, increasing pollution of river channel and floodplain environments, and anthropogenic global warming-related changes in the frequency of floods and droughts. These will have major environmental and societal impacts worldwide. We consider how rivers initially shaped societies, and then how urbanisation, industrialisation and intensified agriculture have more recently transformed river systems, so compromising planetary health and human ways of life. So where do we go from here? Humanity now faces an existential environmental catastrophe of its own making, and it will be on the world's most densely populated floodplains where this crisis will be played out. We highlight likely areas facing the greatest challenges. Ironically, many of these are where ancient civilisations began. Interdisciplinary catchment-based approaches, and new technologies such as those based on satellite imagery and unmanned aerial vehicles, are now beginning to address pressing societal and planetary problems in the unfolding climate crisis.

The availability of water at the ground surface for vector mosquito larval habitats is a critical environmental control of malaria transmission. While ambient air temperature controls the rate of several components of the malaria transmission cycle, extensive laboratory and field studies mean that suitable temperature ranges are well established. In contrast, estimation of surface water availability from current global datasets remains challenging. Instead, monthly rainfall is typically used as a proxy for habitat availability; a threshold of 80 mm per month has gained traction as a proxy for breeding habitat in continental-scale models of malaria climate suitability in Africa and has been applied across the globe. However, since complex and spatially variable hydrological processes (e.g. infiltration, evaporation, soil moisture storage, transfer through and storage in river networks) are omitted, a wide variety of rainfall thresholds are found in the literature that leads to large differences in environmental suitability estimates. Moreover, irrigated areas have been observed to provide suitable year-round habitat for Anopheles mosquitos but are not included in such models. Here we show that across continental Africa, the estimated geographic range of climatic suitability for malaria transmission is more sensitive to precipitation thresholds than the thermal response curves applied. To address this problem and provide a more physical-basis for larval habitat estimation, we use daily climate predictions from seven downscaled general circulation models to run a continental-scale hydrological model (Lisflood) for a process-based representation of mosquito breeding habitat availability. A more complex pattern of malaria climatic suitability emerges as water is routed through drainage networks and river corridors serve as year-round transmission foci. The area estimated to be hydro-climatically suitable for stable malaria transmission is smaller than previous models suggest; however, more people are found in longer-transmission season areas due to higher-density populations along rivers and in irrigated areas. Hydro-climatic predictions of malaria suitable areas show only a very small increase in state-of-the-art future climate scenarios; however, bigger geographical shifts are observed than with most rainfall threshold models and the pattern of that shift is very different when a hydrological model is used to estimate surface water availability for vector breeding.

Soil contamination by heavy metals is common in floodplains throughout the world. Apart from other assessment techniques available, hyperspectral remote sensing is widely used as it offers a lucrative and fast assessment. The current work explores the possibility of on-field and laboratory spectroradiometry investigations together with geochemical data of lead (Pb), zinc (Zn), copper (Cu), and cadmium (Cd) in quantifying and modeling heavy metal soil contamination (HMSC) for a floodplain situated in Wales, United Kingdom. The goal of the study was to (1) gather on-field- as well as lab-based spectra from contaminated soils using analytical spectral devices FieldSpec3, in the spectrum range of 350–2500 nm; (2) construct spectral libraries of on-field- as well as lab-based readings; (3) carry out geochemical analyses of Pb, Zn, Cu, and Cd with the help of an atomic absorption spectrometer; (4) recognize the explicit spectral areas accompanying the modeling of HMSC; and (5) develop and validate heavy metal prediction models (HMPMs) through the spectral features of the contaminants and their concentrations in the soil. Two spectral libraries were developed from the on-field- and lab-based spectral features, which were derived from 85 soil samples. These spectral libraries along with the concentrations of Pb, Zn, Cu, and Cd were joint to construct eight HMPMs by stepwise multiple linear regression. The output provided, for the first time, the viability to predict HMSC in a highly contaminated floodplain site through the combination of geochemical analyses and field spectroradiometry. The resultant model offered support for mapping heavy metal concentrations over a huge area using space-borne hyperspectral sensors.

The Royal Geographical Society (with IBG) annual Medals and Awards recognise achievements in researching, communicating and teaching a wide range of geographical knowledge. The speeches and citations are a record of the 2018 celebration, with contributions from Professors Wendy Larner, Mark Macklin, Yadvinder Malhi, Bhaskar Vira, and Paul Rose. The speeches include comments on: the importance of geography for solving the most pressing of societal challenges; inspiring others through teaching, public engagement and leadership; interdisciplinarity and the pursuit of common intellectual agendas; fostering environmentally, economically and socially just futures; interconnections and exploration of the ecological world; and the value of field science.

This paper reports the first reconstruction of storm-generated late Holocene and historical river floods in the North Island of New Zealand. The sedimentary infills of nine palaeochannels were studied in the lower alluvial reaches of the Manawatu River. Floods in these palaeochannels were recorded as a series of sand-rich units set within finer-grained fills. Flood chronologies were constrained using a combination of radiocarbon dating, documentary sources, geochemical markers, and palynological information. Flood units were sedimentologically and geochemically characterised using high resolution ITRAX™ X-Ray Fluorescence (XRF) core scanning and laser diffraction grain-size analysis. The longest palaeoflood record extends back ca.3000 years. The temporal resolution and length of the Manawatu record reflects accommodation space for fluvial deposits, channel dynamics and mobility, and high sediment supply. Floods that occurred in the Manawatu during the mid-1800s at the time of European land clearance and in the first decade of the twentieth century appear to be among the largest recorded in the last 3000 years.

A significant but previously unquantified factor in anthropogenic change in Australian rivers was the release of large volumes of sediment produced by gold mining in the 19th century. This material, known historically as ‘sludge’, rapidly entered waterways adjacent to mining areas and caused major environmental damage. We interrogate detailed historical records from the colony of Victoria spanning the period 1859 to 1891 to reconstruct the temporal and spatial distribution of sediment volumes released by mining activity. Based on these records, we estimate that at least 650 million m3 of material was released into rivers in the 19th century, exceeding natural sediment yield to rivers by an average 140 times. Although the sediment yield per river is not high when compared with examples around the world, the widespread impacts of sludge distinguishes the case of Victoria. The sludge affected three-quarters of catchments in the state due to the large number of small mining operations spread over hundreds of creeks and gullies across the colony. The impacts of sludge to rivers and farmland filled newspapers for more than 50 years and generated numerous parliamentary inquiries. Today, the impacts are largely forgotten and unrecognised, as are the continuing impacts on aquatic systems. The estimates generated in this study provide a basis for understanding the continuing impact of historical mining on Victorian rivers.

Long highly-resolved proxies for runoff are in high demand for hydrological forecasts and water management in arid Central Asia. An accurate (R2 = 0.53) reconstruction of October-September discharge of the Ili River in Kazakhstan, 1779–2015, is developed from moisture-sensitive tree rings of spruce sampled in the Tian Shan Mountains. The fivefold extension of the gauged discharge record represents the variability of runoff in the Lake Balkhash Basin for the last 235 years. The reconstruction shows a 40 year long interval of low discharge preceded a recent high peak in the first decade of the 2000s followed by a decline to more recent levels of discharge not seen since the start of the gauged record. Most reconstructed flow extremes (± 2σ) occur outside the instrumental record (1936–2015) and predate the start of large dam construction (1969). Decadal variability of the Ili discharge corresponds well with hydrological records of other Eurasian internal drainages modeled with tree rings. Spectral analysis identifies variance peaks (highest near 42 year) consistent with main hemispheric oscillations of the Eurasian climatic system. Seasonal comparison of the Ili discharge with sea-level-pressure and geopotential height data suggests periods of high flow likely result from the increased contribution of snow to runoff associated with the interaction of Arctic air circulation with the Siberian High-Pressure System and North Atlantic Oscillation.

Using a combination of stream gauge, historical and palaeoflood records to extend extreme flood records has proven to be useful in improving flood frequency analysis (FFA). The approach has typically been applied in localities with long historical records and/or suitable river settings for palaeoflood reconstruction from slackwater deposits (SWDs). However, many regions around the world have neither extensive historical information nor bedrock gorges suitable for SWDs preservation and palaeoflood reconstruction. This study from subtropical Australia demonstrates that confined, semi-alluvial channels such as macrochannels provide relatively stable boundaries over the 1000-2000 year time period and the preserved SWDs enabled palaeoflood reconstruction and their incorporation into FFA. FFA for three sites in subtropical Australia with the integration of historical and palaeoflood data using Bayesian Inference methods showed a significant reduction in uncertainty associated with the estimated discharge of a flood quantile. Uncertainty associated with estimated discharge for the 1% Annual Exceedance Probability (AEP) flood is reduced by over 50%. In addition, sensitivity analysis of possible within-channel boundary changes shows that FFA is not significantly affected by any associated changes in channel capacity. Therefore, a greater range of channel types may be used for reliable palaeoflood reconstruction by evaluating the stability of inset alluvial units, thereby increasing the quantity of temporal data available for FFA. The reduction in uncertainty, particularly in the prediction of the ≤ 1% AEP design flood, will improve flood risk planning and management in regions with limited temporal flood data. This article is protected by copyright. All rights reserved.

Along the eastern margin of Australia, hydrological variability reaches a peak in the subtropics of south-east Queensland and many rivers have entrenched characteristics. To address the nature of entrenchment and the relationship with adjacent alluvium, this paper presents the results of detailed chrono-stratigraphic analysis of alluvial units in the partly confined mid-reaches of Lockyer Creek, Australia. Four sites were investigated using topographic, sedimentological and chronological data. Radiocarbon and single grain optically stimulated luminescence dating indicate a large proportion of the valley fill reflects a major phase of aggradation of fine-grained alluvium from ca. 35 ka throughout the Last Glacial Cold Period. Synchronous incision of Pleistocene alluvial fills between 11.5 and 9.3 ka suggests the current entrenched Lockyer Creek formed in response to changes in late Quaternary climate. Holocene floodplains set within the entrenched Pleistocene valley floor have basal ages of ca. 7.5 ka, but whose proximal margins are still actively accreting. This Holocene fill has accreted over the mid- to late Holocene but overlaps with the contemporary hydrological regime. The sedimentary nature of the Holocene fill appears to be related to persistent antecedent controls in the form of bedrock and terrace constriction.

Major floods have increased in frequency in many parts of the world, and this is often attributed to anthropogenic climate change. Because of the short length of most gauged records (∼50 yr), it is unclear whether these events represent a short-term anomaly or a shift to a prolonged flood-rich period. In this paper, we use event-scale paleoflood records from upland and lowland floodplains to demonstrate the relationship between individual flood events, clusters of events in multiyear episodes, and multidecadal- to centennial-scale flood-rich phases. Catchment- and regional-scale data show that individual events and episodes generally fall within extended flood-rich phases controlled by climate. Furthermore, contrary to recent suggestions that environmental signals may be rendered incomplete in fluvial systems by autogenic processes, from a multidecadal (and longer) perspective it is clear that floodplain environments can register and preserve a useful multiscale hydromorphic signal of climate change.

The degree to which the climate change signal can be seen in the increasing frequency and/or magnitude of extreme events forms a key part of the global environmental change agenda. Geomorphology engages with this debate through extending the instrumental record with palaeogeomorphological research; studying resilience and recovery of geomorphic systems under extreme disturbance; documenting the mediation by catchment organisation of transport processes during extreme events; applying new monitoring methods to better understand process-response systems; and illustrating how process, experimental and modelling insights can be used to define the buffering of geomorphic systems and human assets from the effects of extremes, providing practical outcomes for practitioners. This article is protected by copyright. All rights reserved.

In this chapter, we discuss recent developments in paleoflood hydrology that are specific to the collection of high-resolution records from alluvial settings. We describe how to develop and analyze alluvial paleoflood records, including (i) the identification of suitable depositional niches in valley environments and the mechanisms of overbank deposition that lead to flood deposit accumulation at those locations, (ii) approaches for sample material collection and methods to measure the coarseness of individual flood units, (iii) data assessment and reconstruction of absolute and relative flood magnitudes from sedimentary information, and (iv) developing flood chronologies with a discussion of available dating techniques. We argue that alluvial paleoflood archives hold enormous potential for flood hazard assessments in densely populated low-lying areas despite the challenge of quantitative discharge reconstructions in dynamic floodplain settings.

Results from the analysis of aqueous and solid-phase V speciation within samples collected from the Hazeltine Creek catchment affected by the August 2014 Mount Polley mine tailings dam failure in British Columbia, Canada, are presented. Electron microprobe and X-ray absorption near-edge structure (XANES) analysis found that V is present as V

This study presents a new analytical framework for combining historical flood data derived from sedimentological records with instrumental river flow data to increase the reliability of flood risk assessments. Historical flood records were established for two catchments through re-analysis of sedimentological records; the Nant Cwm-du, a small, steep upland catchment in the Cambrian Mountains of Wales, and a piedmont reach of the River Severn in mid Wales. The proposed framework is based on maximum likelihood and least-square estimation methods in combination with a Generalised Logistic distribution; this enables the sedimentological data to be combined effectively with existing instrumental river flow data. The results from this study are compared to results obtained using existing industry standard methods based solely on instrumental data. The comparison shows that inclusion of sedimentological data can have an important impact on flood risk estimates, and that the methods are sensitive to assumptions made in the conversion of the sedimentological records into flood flow data. As current industry standard methods for flood risk analysis are known to be highly uncertain, the ability to include additional evidence of past flood events derived from sedimentological records as demonstrated in this study can have a significant impact on flood risk assessments.

Technological advances in hyperspectral remote sensing have been widely applied in heavy metal soil contamination studies, as they are able to provide assessments in a rapid and cost-effective way. The present work investigates the potential role of combining field and laboratory spectroradiometry with geochemical data of lead (Pb), zinc (Zn), copper (Cu) and cadmium (Cd) in quantifying and modelling heavy metal soil contamination (HMSC) for a floodplain site located in Wales, United Kingdom. The study objectives were to: (i) collect field- and lab-based spectra from contaminated soils by using ASD FieldSpec&reg, 3, where the spectrum varies between 350 and 2500 nm, (ii) build field- and lab-based spectral libraries, (iii) conduct geochemical analyses of Pb, Zn, Cu and Cd using atomic absorption spectrometer, (iv) identify the specific spectral regions associated to the modelling of HMSC, and (v) develop and validate heavy metal prediction models (HMPM) for the aforementioned contaminants, by considering their spectral features and concentrations in the soil. Herein, the field- and lab-based spectral features derived from 85 soil samples were used successfully to develop two spectral libraries, which along with the concentrations of Pb, Zn, Cu and Cd were combined to build eight HMPMs using stepwise multiple linear regression. The results showed, for the first time, the feasibility to predict HMSC in a highly contaminated floodplain site by combining soil geochemistry analyses and field spectroradiometry. The generated models help for mapping heavy metal concentrations over a huge area by using space-borne hyperspectral sensors. The results further demonstrated the feasibility of combining geochemistry analyses with filed spectroradiometric data to generate models that can predict heavy metal concentrations.

River flooding is among the most destructive of natural hazards globally, causing widespread loss of life, damage to infrastructure and economic deprivation. Societies are currently under increasing threat from such floods, predominantly from increasing exposure of people and assets in flood¿prone areas, but also as a result of changes in flood magnitude, frequency, and timing. Accurate flood hazard and risk assessment are therefore crucial for the sustainable development of societies worldwide. With a paucity of hydrological measurements, evidence from the field offers the only insight into truly extreme events and their variability in space and time. Historical, botanical, and geological archives have increasingly been recognized as valuable sources of extreme flood event information. These different archives are here reviewed with a particular focus on the recording mechanisms of flood information, the historical development of the methodological approaches and the type of information that those archives can provide. These studies provide a wealthy dataset of hundreds of historical and palaeoflood series, whose analysis reveals a noticeable dominance of records in Europe. After describing the diversity of flood information provided by this dataset, we identify how these records have improved and could further improve flood hazard assessments and, thereby, flood management and mitigation plans., This publication is a contribution to the Past Global Changes (PAGES) Floods Working Group. PAGES is supported by the US National Science Foundation and the Swiss Academy of Sciences.

Expansion of agricultural practices from the Fertile Crescent to China during the mid and late Holocene are believed to have shaped the early network of Silk Road routes and possibly regulated the dynamics of trade and exchange in the urban oases along the Silk Road throughout its existence. While the impacts of climate change on the Silk Road are more or less documented for the medieval period, they remain poorly understood for early history of the Silk Road, especially in Central Asia. We analyze hydroclimatic proxies derived from fluvial stratigraphy, geochronology, and tree-ring records that acted on various time scales in the Lake Balkhash Basin to learn how changes in water supply could have influenced the early farmers in the Semirechye region of southern Kazakhstan. Our approach aims to identify short-term and long-term variability of regional runoff and to compare the hydrological data with cultural dynamics coupled with the archaeological settlement pattern and agricultural production. The reconstructed runoff variability underscore the contribution of winter precipitation driven by the interaction between the Arctic oscillation and the Siberian High-Pressure System, to Central Asian river discharge. We show that Saka people of the Iron Age employed extensive ravine agriculture on the alluvial fans of the Tian Shan piedmont, where floodwater farming peaked between 400 BC and 200 BC. The early Silk Road farmers on the alluvial fans favored periods of reduced flood flows, river stability and glacier retreat in the Tian Shan Mountains. Moreover, they were able to apply simple flow control structures to lead water across the fan surface. It is very unlikely that changes in water supply ever significantly constricted agricultural expansion in this region.

Climate change is expected to significantly affect flooding regimes of river systems in the future. For Western Europe, flood risk assessments generally assume an increase in extreme events and flood risk, and as a result major investments are planned to reduce their impacts. However, flood risk assessments for the present day and the near future suffer from uncertainty, coming from short measurements series, limited precision of input data, arbitrary choices for particular statistical and modelling approaches, and climatic non-stationarities. This study demonstrates how historical and sedimentary information can extend data records, adds important information on extremes, and generally improves flood risk assessments. The collection of specific data on the occurrence and magnitude of extremes and the natural variability of the floods is shown to be of paramount importance to reduce uncertainty in our understanding of flooding regime changes in a changing climate. For the Lower Rhine (the Netherlands and Germany) estimated recurrence times and peak discharges associated with the current protection levels correlate poorly with historical and sedimentary information and seem biased towards the recent multi-decadal period of increased flood activity. Multi-decadal and centennial variability in flood activity is recorded in extended series of discharge data, historical information and sedimentary records. Over the last six centuries that variability correlates with components of the Atlantic climate system such as the North Atlantic Oscillation (NAO) and Atlantic Multi-decadal Oscillation (AMO). These climatic non-stationarities importantly influence flood activity and the outcomes of flood risk assessments based on relatively short measurement series. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Mitrovica, northern Kosovo, is the site of some of the highest Pb concentrations reported in human populations; exemplified by Pb concentrations in scalp hair of up to 130 μg g-1 and widely-publicized of Pb-related ill-health and mortality amongst internally displaced populations. High human Pb burdens are accompanied by elevated concentrations of potentially harmful elements (PHEs) in soils and house dust within the city, which has a long history of mining and metallurgy. In this study enrichment-levels for PHEs in soils are quantified and compared to environmental quality guidelines and a statistically-derived estimation of background concentration. In addition, Pb isotopes (207Pb/206Pb, 208Pb/206Pb) are used to characterise the isotopic signatures of potential point sources of Pb and a mixing model employed to quantify the contribution of sources to Pb present in soils, house dust, and the scalp hair of children and young people. Pb isotopic evidence suggests that Pb in surface soils and house-dust is predominantly sourced from historical deposition of Pb-containing aerosols from metal smelting, with lower contributions from wind-blown dispersal of metalliferous waste. Pb present in scalp hair is interpreted as the result of non-occupational exposure and the ingestion and/or inhalation of Pb-enriched surface soil and house dust. This study represents one of the very few instances where this type of geochemical tracing technique has been successfully applied to definitively identify the source of Pb present within biological samples. The results of this study are of particular relevance to environmental management and highlight the human health risk posed by the legacy of now inactive mining and metallurgy in addition to the challenge posed in mitigating the risk posed by diffuse soil pollution. © 2015 Elsevier Ltd.

In comparison to Southwest Asia and the Indian subcontinent, the relationship between Holocene river dynamics, climate change and floodwater farming in Central Asia is significantly under researched. To address this, a multi-disciplinary research project was begun in 2011 centred on the Talgar catchment, a south-bank tributary of the Ili River, southeast Kazakhstan. Building on archaeological excavations and surveys conducted over the past 20 years, we have undertaken investigations of Holocene human adaptations to changing hydromorphic regimes in the Tien Shan piedmont region, Central Asia. Fluvial geochronologies have been reconstructed over the last 20,000 years using Optically Stimulated Luminescence and 14C dating, and are compared with human settlement histories from the Eneolithic to the medieval period. Phases of Late Pleistocene and Holocene river aggradation at c. 17,400–6420, 4130–2880 and 910–500 cal. BC and between the mid-18th and early 20th centuries were coeval with cooler and wetter neoglacial episodes. Entrenchment and floodplain soil development (c. 2880–2490 cal. BC and cal. AD 1300–1640) coincided with warmer and drier conditions. Prior to the modern period, floodwater farming in the Talgar River reached its height in the late Iron Age (400 cal. BC – cal. AD 1) with more than 70 settlement sites and 700 burial mounds. This period of agricultural expansion corresponds to a phase of reduced flooding, river stability and glacier retreat in the Tien Shan Mountains. Late Iron age agriculturists appear to have been opportunistic by exploiting a phase of moderate flows within an alluvial fan environment, which contained a series of partially entrenched distributary channels that could be easily ‘engineered’ to facilitate floodwater farming. Holocene climate change was therefore not a proximate cause for the development and demise of this relatively short-lived (c. 200 years) period of Iron Age farming. River dynamics in the Tien Shan piedmont are, however, strongly coupled with regional hydroclimatic fluctuations, and they have likely acted locally as both ‘push’ and ‘pull’ factors for riparian agriculturists.

It has long been hypothesised that beds of highly organic mud or sapropels seen in marine sediment cores retrieved from the floor of the eastern Mediterranean accumulated during times of high Nile fluvial discharge. Our recent fieldwork in the valleys of the Blue Nile, the White Nile and the main Nile has for the first time revealed a sequence of extreme flood episodes synchronous with sapropel units S5 (124 kyr), S4 (102 kyr), S3 (81 kyr), S2 (55 kyr) and S1 (13.5–6.5 kyr). There are more weakly defined links with Nile floods and sapropel units S9 (240 kyr), S8 (217 kyr), S7 (195 kyr), S6 (172 kyr), but the dating error terms are too large to allow us to be too definite. During times of extreme floods over the past 125 kyr, wide distributary channels of the Blue Nile flowed across the Gezira alluvial fan in central Sudan and transported a bed load of sand and gravel into the lower White Nile valley. The sands were reworked by wind to form source-bordering dunes, all of which contain heavy minerals of Ethiopian provenance. These source-bordering dunes were active at 115–105 kyr, 60 kyr and 12–7 kyr, all times of extreme Blue Nile floods. The flood and dune sediments were dated using a combination of optically stimulated luminescence (OSL) and radiocarbon analyses. The Quaternary record of Nile floods discussed here shows a precessional signal and reflects episodes of stronger summer monsoon and more northerly seasonal movement of the ITCZ, linked to times of higher insolation in northern tropical latitudes. Progressive aggradation of Holocene Nile channels in northern Sudan has had a profound influence upon human settlement in the last 8 kyr.

We have reconstructed long-term shifts in catchment sediment sources by analysing, for the first time, the strontium (Sr) and neodymium (Nd) isotope composition of dated floodplain deposits in the Desert Nile. The sediment load of the Nile has been dominated by material from the Ethiopian Highlands for much of the Holocene, but tributary wadis and aeolian sediments in Sudan and Egypt have also made major contributions to valley floor sedimentation. The importance of these sources has shifted dramatically in response to global climate changes. During the African Humid Period, before c. 4.5 ka, when stronger boreal summer insolation produced much higher rainfall across North Africa, the Nile floodplain in northern Sudan shows a tributary wadi input of 40–50%. Thousands of tributary wadis were active at this time along the full length of the Saharan Nile in Egypt and Sudan. As the climate became drier after 4.5 ka, the valley floor shows an abrupt fall in wadi inputs and a stronger Blue Nile/Atbara contribution. In the arid New Kingdom and later periods, in palaeochannel fills on the margins of the valley floor, aeolian sediments replace wadi inputs as the most important secondary contributor to floodplain sedimentation. Our sediment source data do not show a measurable contribution from the White Nile to the floodplain deposits of northern Sudan over the last 8500 years. This can be explained by the distinctive hydrology and sediment delivery dynamics of the upper Nile basin. High strontium isotope ratios observed in delta and offshore records – that were previously ascribed to a stronger White Nile input during the African Humid Period – may have to be at least partly reassessed. Our floodplain Sr records also have major implications for bioarchaeologists who carry out Sr isotope-based investigations of ancient human remains in the Nile Valley because the isotopic signature of Nile floodplain deposits has shifted significantly over time.

© 2015 Elsevier Ltd. In the Nile catchment, a growing number of site- and reach-based studies employ radiocarbon and, more recently, OSL dating to reconstruct Holocene river histories, but there has been no attempt to critically evaluate and synthesise these data at the catchment scale. We present the first meta-analysis of published and publically available radiocarbon and OSL dated Holocene fluvial units in the Nile catchment, including the delta region, and relate this to changing climate and river dynamics. Dated fluvial units are separated both geographically (into the Nile Delta and White, Blue, and Desert Nile sub-regions) and into depositional environment (floodplain and palaeochannel fills). Cumulative probability density frequency (CPDF) plots of floodplain and palaeochannel units show a striking inverse relationship during the Holocene, reflecting abrupt (

The occurrence of devastating floods in the British uplands during the first two decades of the twenty-first century poses two key questions: (1) are recent events unprecedented in terms of their frequency and magnitude; and (2) is climate and/or land-use change driving the apparent upturn in flooding? Conventional methods of analysing instrumental flow records cannot answer these questions because upland catchments are usually ungauged, and where records do exist they rarely provide more than 30-40 years of data. In this paper we analyse all lichen-dated upland flood records in the United Kingdom (UK) to establish the longer-term context and causes of recent severe flooding. Our new analysis of torrential sedimentary deposits shows that twenty-first century floods are not unprecedented in terms of both their frequency (they were more frequent before 1960) and magnitude (the biggest events occurred during the seventeenth-nineteenth centuries). However, in some areas recent floods have either equalled or exceeded the largest historical events. The majority of recent floods have been triggered by torrential summer downpours related to a marked negative phase of the summer North Atlantic Oscillation (NAO) between 2007 and 2012. It is of concern that historical data suggests there is far more capacity in the North Atlantic climate system to produce wetter and more prolonged flood-rich periods than hitherto experienced in the twenty-first century. Looking forwards, an increased likelihood of weather extremes due to climate change means that geomorphological based flood series extensions must be placed at the centre of flood risk assessment in the UK uplands and in similar areas worldwide. © 2016 John Wiley & Sons, Ltd.

The continuing development of computational fluid dynamics is allowing the high resolution study of hydraulic and sediment transport processes but, due to computational complexities, these are rarely applied to areas larger than a reach. Existing approaches, based upon linked cross sections, can give a quasi two-dimensional view, effectively simulating sediment transport for a single river reach. However, a basin represents a whole discrete dynamic system within which channel, floodplain and slope processes operate over a wide range of space and time scales. Here, a cellular automaton (CA) approach has been used to overcome some of these difficulties, in which the landscape is represented as a series of fixed size cells. For every model iteration, each cell acts only in relation to the influence of its immediate neighbours in accordance with appropriate rules. The model presented here takes approximations of existing flow and sediment transport equations, and integrates them, together with slope and floodplain approximations, within a cellular automaton framework. This method has been applied to the basin of Cam Gill Beck (4.2 km2 ) above Starbotton, upper Wharfedale, a tributary of the River Wharfe, North Yorkshire, UK. This approach provides, for the first time, a workable model of the whole basin at a 1 m resolution. Preliminary results show the evolution of bars, braids, terraces and alluvial fans which are similar to those observed in the field, and examples of large and small scale non-linear behaviour which may have considerable implications for future models.

Field geologists and geomorphologists are increasingly looking to numerical modelling to understand landscape change over time, particularly in river catchments. The application of landscape evolution models (LEMs) started with abstract research questions in synthetic landscapes. Now, however, studies using LEMs on real-world catchments are becoming increasingly common. This development has philosophical implications for model specification and evaluation using geological and geomorphological data, besides practical implications for fieldwork targets and strategy. The type of data produced to drive and constrain LEM simulations has very little in common with that used to calibrate and validate models operating over shorter timescales, making a new approach necessary. Here we argue that catchment fieldwork and LEM studies are best synchronized by complementing the Pattern Oriented Modelling (POM) approach of most fluvial LEMs with Pattern Oriented Sampling (POS) fieldwork approaches. POS can embrace a wide range of field data types, without overly increasing the burden of data collection. In our approach, both POM output and POS field data for a specific catchment are used to quantify key characteristics of a catchment. These are then compared to provide an evaluation of the performance of the model. Early identification of these key characteristics should be undertaken to drive focused POS data collection and POM model specification. Once models are evaluated using this POM/POS approach, conclusions drawn from LEM studies can be used with greater confidence to improve understanding of landscape change.

There is an emerging and urgent need for new approaches for the management of environmental challenges such as flood hazard in the broad context of sustainability. This requires a new way of working which bridges disciplines and organisations, and that breaks down science-culture boundaries. With this, there is growing recognition that the appropriate involvement of local communities in catchment management decisions can result in multiple benefits. However, new tools are required to connect organisations and communities. The growth of cloud based technologies offers a novel way to facilitate this process of exchange of information in environmental science and management; however, stakeholders need to be engaged with as part of the development process from the beginning rather than being presented with a final product at the end. Here we present the development of a pilot Local Environmental Virtual Observatory Flooding Tool. The aim was to develop a cloud based learning platform for stakeholders, bringing together fragmented data, models and visualisation tools that will enable these stakeholders to make scientifically informed environmental management decisions at the local scale. It has been developed by engaging with different stakeholder groups in three catchment case studies in the UK and a panel of national experts in relevant topic areas. However, these case study catchments are typical of many northern latitude catchments. The tool was designed to communicate flood risk in locally impacted communities whilst engaging with landowners/farmers about the risk of runoff from the farmed landscape. It has been developed iteratively to reflect the needs, interests and capabilities of a wide range of stakeholders. The pilot tool combines cloud based services, local catchment datasets, a hydrological model and bespoke visualisation tools to explore real time hydrometric data and the impact of flood risk caused by future land use changes. The novel aspects of the pilot tool are; the co-evolution of tools on a cloud based platform with stakeholders, policy and scientists; encouraging different science disciplines to work together; a wealth of information that is accessible and understandable to a range of stakeholders; and provides a framework for how to approach the development of such a cloud based tool in the future. Above all, stakeholders saw the tool and the potential of cloud technologies as an effective means to taking a whole systems approach to solving environmental issues. This sense of community ownership is essential in order to facilitate future appropriate and acceptable land use management decisions to be codeveloped by local catchment communities. The development processes and the resulting pilot tool could be applied to local catchments globally to facilitate bottom up catchment management approaches. © 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license