Fluvial Geomorphology Research Papers - Academia.edu (original) (raw)

Diamond-bearing gravels of the Lichtenburg-Ventersdorp area of the North West Province are associated with north-south orientated sinuous 'runs' that occur almost entirely on a flat erosional surface of the Malmani dolomites (Transvaal Supergroup) at some 1,500 m elevation. East to west, this dolomite plain measures 150 km, and north-south it is on average 40 km wide. This unconformity, which first developed before the Pretoria Group sedimentation over a period of at least 80 Myr, is marked by siliceous breccias (palaeo-karst infill) and conglomerates (reworked breccias). It was exhumed in pre-Karoo and post-Gondwana times. Glacial pavements and remnants of thin Lower Karoo sediments are also found on this polyphase surface. The gravels that make up these 'runs' and sinkholes directly or indirectly linked to these runs, are coarse-grained, very poorly-sorted, and are best described as diamictites. The 'runs' are narrow, elongated, generally positive ridges that meander across the dolomite surface and are up to 30 km long and between 80 to 300 m wide. They have always been regarded as post-Cretaceous drainage features linked to southward-flowing river systems. Diamonds were discovered in these 'runs' and they have produced some 12 million carats. However, no Cainozoic fossils or artefacts have ever been found in almost 90 years of mining. From new field evidence, geomorphological studies, age dating from inclusions in diamond and zircon and clay analyses, it is proposed that these coarse-grained runs represent proximal palaeo-eskers of the last deglaciation of the Dwyka continental ice sheet, that are preserved on this ancient 'palimpsest' surface. The age of the deposit is constrained by two populations of agate within the diamictites that are linked to two separate volcanic units of the Pretoria Group. In addition, the youngest crustal zircon ages from the gravels are 1 Ba, but mantle zircons from Lichtenburg suggest that these have been derived from Cambrian age kimberlites. Analysis of inclusions in diamond support a Neoproterozoic to Cambrian source for the diamonds, so the absence of diamonds from Mesozoic kimberlites and Cainozoic fossils within the gravels support the conclusion that the runs are of Karoo age.

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- Fluvial Geomorphology, Fluvial Sedimentology, Diamond exploration

Over the last century, geomorphic processes along the Middle Rio Grande have been altered by flood control and bank stabilization projects, intensified land and water use, and climate change. In response to potential risks to infrastructure and ecological integrity, recent (1985–2008) adjustment was investigated and historic (1918–1985) changes in Rio Grande channel planform through the Albuquerque, New Mexico, area were reviewed, especially in relation to changes in annual peak discharge and river engineering measures. Using a GIS, channel characteristics were digitized from georeferenced photographs and analyzed with particular attention to quantifying potential measurement error and its propagation. Error associated with average channel widths and channel area ranged between 4 and 13%. For smaller polygons, e.g. islands, error was higher (11 to 40% for width and >200% for area) because width error is large relative to polygon width. Between 1918 and 1963, average channel widths decreased 8 m/yr, from 516 67 m to 176 7 m, mostly due to decreasing peak flows and the implementation of flood control and other engineering measures. From 1985 to 2008, widths decreased 0·7 m/yr, from 176 23 m to 146 5 m, accompanied by an increase in vegetated island area which largely coincided with low flow periods. Narrowing was concentrated at tributary inputs and in the upstream part of the reach, where bedload trapping by Cochiti Dam has caused degradation. Bank protection structures and dense vegetation limit bank erosion in the reach, but erosion is significant where expanding islands, incision, and increased meandering force water against banks.

- by Grant Meyer
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- Fluvial Geomorphology

... Urban channels, Erodibility, Allen et al. (2002). Urban channels, Spatial management in relation to hazards, Chin and Gregory (2005). Plunge pools, Act as energy dissipators to increase flow resistance and enhance channel stability,... more

- by Gerardo Benito
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- Geology, Geomorphology, Environmental Ethics, Applied Research

O presente livro apresenta uma rica abordagem sobre os
estudos relacionados ao tema do Tecnógeno e Antropoceno,
vinculado a uma perspectiva eminentemente geográfica. Neste
sentido, a Geografia como a ciência que estuda o espaço
geográfico, sendo este materializado a partir das relações que a
sociedade exerce sobre a natureza, não poderia deixar de se furtar
a respeito do tema das transformações que a sociedade tem
acarretado ao ambiente, gerando modificações nas formas de
relevo em áreas urbanas.
https://asebabaolorigbin.files.wordpress.com/2021/04/geomorfologia-tecno-antropo.pdf

- by Pedro França Junior
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- Geography, Physical Geography, Geomorphology, Fluvial Geomorphology

Fluvial sediments are valuable paleoenvironmental archives of the Quaternary. Since besides environmental factors they are also affected by local tectonics or intrinsic processes, large instead of small catchments should be studied. In drylands covering ca. 45% of the global terrestrial surface large river systems are generally missing, and most river systems are small rivers originating from mountain ranges. Their sediments are potentially interesting paleoenvironmental archives, but are often affected by intensive tectonics. During this study, to obtain a robust regional paleoenvironmental signal a small river system in the southwestern Binaloud Mountains in semi-arid NE Iran was exemplarily studied with a combined approach that encompassed both alluvial fan and catchment. By using geomorphological mapping and numerical dating, fluvial aggradation followed by incision was independently identified in larger areas or in different parts of the river system ca. 95-88 ka, 40 ka, 20 ka, around/after the Pleistocene/Holocene transition and possibly ca. 2.6 ka. These could be linked with regional and over-regional paleoenvironmental data. Furthermore, large boulders on the alluvial fan suggest anthropogenic destabilisation of the catchment during the last decades. Despite strong local tectonics the fluvial dynamics was mostly controlled by paleoenvironmental changes and human activity. This indicates that despite their small size, such river systems form valuable paleoenvironmental archives in drylands where other archive types are largely missing.

This one-day field trip highlighted research into the late Holocene geomorphic evolution and land-use history of Piedmont stream valleys near Raleigh, North Carolina. European settlers began building water-powered milldams in the eastern United States in the 1600s, and dam construction continued until the early twentieth century. At the same time, regional-scale land clearing associated with agriculture and development increased upland erosion rates 50-400 times above long-term geologic rates. Much of the eroded sediment was subsequently aggraded on floodplains and impounded behind milldams. This trapped "legacy" sediment, commonly mistaken for natural floodplain deposition, has gone largely unrecognized until recently. Geomorphic mapping demonstrates that upland soil erosion and valley bottom sediment aggradation was substantial following European-American land acquisition and their conversion of large amounts of forest land for agricultural purposes. The pre-dam sediments consist primarily of fluvial sands, and are interpreted as channel aggradation in response to soil erosion from upland land clearing prior to dam construction. Post-dam sediments are distinguished by finer grain size and sedimentology consistent with slackwater deposition, including sandy "event" layers, interpreted to be the result of large floods into the former mill ponds.

- by Robert Q Lewis
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- Fluvial Geomorphology, Stream Restoration, mill dams

The article deals with a problem of geomorphologic processes dynamics in the small river basin, as influenced by human activity and climatic fluctuations. The model basin was a small watershed draining in the upper course of Dnister river, characterized by a long period of human impact. The dynamics of river’s structure, morphological processes and land use changes per last 70 years was presented.

This study examined gully development in Demekpe drainage basin, Makurdi Local Government Area of Benue State of Nigeria; with a view to determine the volume and amount of sediment loss from a 3 rd order gully system. The systematic sampling technique was used to segment the gully which measured 220m long at intervals of 20m. Parameters measured include among others gully length, gully depth, gully shoulder and bed widths, slope gradient, cross sectional area, stream density, stream frequency and stream intensity. Cartesian coordinates, spot heights and core soil values were also determined. Digital Elevation Model was used to model gully form, direction of runoff and sediment delivery ratio in the gully system. The result showed that the volume of sediment loss from the gully system with a cross sectional area of 91.7m 2 is 931.5m 3 using the End Area method of soil loss determination. The amount or weight of sediment loss from the gully system is estimated to be 12,575.28 tonnes. The Digital Elevation Model of the gully system indicates a trapezoidal form and slopes with summital convexity. The convexity of the slope shape implies that runoff is generated from all sides of the slopes, influencing a considerate amount of sediment loss at the gully sides and floor. It is therefore recommended that planting of cover crops should be intensified to enhance infiltration and concreted surfaces should be minimised to reduce surface runoff and sediment loss along slopes.

- by Kehinde Oyatayo Ph.D
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- Fluvial Geomorphology

Geomorphological risk evaluation in outdoor sports: the canyoning. Canyoning is an easy and not very expensive type of sport that has to do with a lot of geomor-phological risks, so it is always important to evaluate the weather and hydrological conditions when practising it. The present study describes the geomorpholo-gical processes and landscapes where canyoning takes place as well as their relative hydrological, weather and climate risks. The climatic limits in the main diffusion areas will also be analyzed as well as in Italy. At last, we examine the interventions in order to reduce the risk in three study areas, and we proposed the better management of Italian canyoning itineraries.
MOTTA L. & MOTTA M. (2007) - La valutazione del rischio geomorfologico negli sport all’aria aperta: l’esempio del canyoning. In: M. Piccazzo (ed.) “Clima e rischio geomorfologico in aree turistiche”. Patron, quarto inferiore (BO), 297-321

- by Michele Motta
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- Geography, Geomorphology, Tourism Studies, Fluvial Geomorphology

Fluvial geomorphology affects river character, behaviour, evolution, trajectory of change and recovery potential, and as such affects biophysical interactions within a catchment. Water bodies in South Africa, in common with many other water-stressed parts of the world, are generally under threat due to increasing natural and anthropogenic influences including aridity, siltation and pollution, as well as climate and environmental change. This study reports on a case study to characterise the geomorphology of different river systems in South Africa, with the aim of better understanding their properties, controls, and implications for biophysical interactions including water quality, biodiversity (aquatic and riparian), and human activity within the catchment. The approach adopted is based on the River Styles® framework (RSF), a geomorphology-based approach developed for rivers in New Zealand and Australia, but applied here for the first time to South Africa. Based on analysis of remote sensing imagery, SRTM-2 digital topographic data and field observations on sites through the entire river system, six geomorphic elements were identified along the Sabie River, northeast South Africa (gorge, bedrock-forced meander, low-moderate sinuosity planform controlled sand bed, meandering sand bed, low sinuosity fine grained sand bed, and floodouts), using the RSF classification scheme and based on the RSF procedural tree of Brierley and Fryirs (2005). Previous geomorphological studies along the Sabie River have shown that different reaches respond differently to episodic floods; we use these data to link river geomorphological character (as defined by the RSF) to the hydrodynamic conditions and processes giving rise to such character. This RSF approach can be used to develop a new management approach for river systems that considers their functional biophysical behaviour within individual reaches, rather than considering them as homogeneous and uniform systems.

- by Jasper Knight
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- Fluvial Geomorphology, Fluvial Sedimentology, Floods, River Geomorphology

We use reach-scale stream gradient as an indicator of longitudinal connectivity for water, sediment, and organic matter in a mountainous watershed in Colorado. Stream reaches with the highest gradient tend to have narrow valley bottoms with limited storage space and attenuation of downstream fluxes, whereas stream reaches with progressively lower gradients have progressively more storage and greater attenuation. We compared the distribution of stream gradient to stream-reach connectivity rankings that incorporated multiple potential control variables , including lithology, upland vegetation, hydroclimatology, road crossings, and flow diversions. We then assessed connectivity rankings using different weighting schemes against stream gradient and against field-based understanding of relative connectivity within the watershed. We conclude that stream gradient, which is simple to map using publicly available data and digital elevation models, is the most robust indicator of relative longitudinal connectivity within the river network.

- by Robert Wasson
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- Geology, Geomorphology, Climate Change, Fluvial Geomorphology

Alternate bars in rivers and streams develop as a result of differences in length scales involved in the adjustment of flow and sediment transport to irregularities of the bed. The amount of field evidence supporting theoretical insights is highly limited. Here, we present results from a large-scale field experiment in a 600 m long straight reach. Over a period of almost 3 years, the channel was allowed to evolve autogenously from initially flat bed conditions, subject to discharge variation. Alternate bars developed within 8 months from the start of the experiment. The initial stages of bar development included bar growth, both in wavelength and amplitude, and bar migration. The latter was too limited to classify the bars as being migrating bars; therefore, we classify the bars as nonmigrating bars. Toward the end of the experiment, the regular alternate bar pattern evolved into an irregular pattern and bar amplitude started to decrease. From the start of the experiment we observed a declining channel slope, from 1.8 m km−1 initially to 0.9 m km−1 halfway the experiment, after which it stabilized. We applied two bar theories to establish their predictive capacity. Both bar theories predicted the development of alternate bars under the constructed channel conditions. In response to the declining channel slope, both theories predicted a decreasing likelihood for the development of alternate bars. Our study shows that under field conditions, the applied bar theories may predict the initial stages of bed development.

EL CUATERNARIO EN ESPAÑA Y ÁREAS AFINES, AVANCES EN 2011 (V. TURU & A. CONSTANTE, Eds.), Andorra la Vella, 127-132

- by Valenti Turu i Michels and +1
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- Fluvial Geomorphology, Pyrénées, Pre-Pyrenees, Glacial Chronology
- by Sandipan Ghosh
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- Geography, Physical Geography, Geomorphology, Fluvial Processes

Flood plain morphology is intimately related to hydraulic characteristics of channel and rate of channel migration which involves in the evolution of the flood plain as well as the channel pattern. Channel migration is a complex geomorphological process driven by the interaction between fluid flow, alluvial channel beds and banks. Channel migration in alluvial flood plains involves in continuous shifting of channel position horizontaly i.e., oscillation of channel in meander belt, which can be distinguished from abrupt changes occurred by avulsion or by tectonic and climatic events. Increasing channel sinuosity results into channel migration which inturn affect the hydraulic geometry of the channel by changing the gradient, depth and width and flow velocity. Channel interchanges its plaimetry from straight to meandering with higher to a lower discharge in alluvial flood plain. Full bank discharge may have the capacity for maximum down cuts. In the upstream direction Nagar River has an average bed to bank depth 4m and in lower reaches it increases upto 5.5 m having a water depth 30cm to 1.6m respectively during pre-monsoon. Therefore, during the monsoon discharge may increase more than 3 times, which may cause valley deeping and migration too. To understand the channel shifting behaviour hydraulic properties of the river is to be explored. This paper attempts to present a detailed account of river hydraulics and channel migration to evaluate the present scenario of the Nagar River.

- by Pankaj Sarkar
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- Fluvial Geomorphology

In the first multipurpose river valley planning of India, the vast resources of Damodar River Basin (DRB) (eastern India) are not only to be envisioned in their entirety but also to be developed in a unified manner where the water, land, and people are simultaneously bounded in a seamless web. Four large dams (Konar, Tilaiya, Maithon, and Panchet), Durgapur barrage, and Tenughat reservoir are built to tamp the flood-prone Damodar River using water resource in an integrated method. The functionality of Damodar fluvial system is controlled by dams, barrage, weirs, sluices, embankments, and canals, maintaining a dynamic equilibrium between fluvial processes and anthropogenic processes. Carrying more than 50 years of legacy, the existing drainage and flood control system of Damodar Valley Corporation has aggravated a number of hydrogeomorphic problems especially in lower DRB, viz. siltation of river bed and reservoirs, uncontrolled monsoonal stream flow, declining carrying capacity of lower course, drainage congestion, low-magnitude annual floods, channel shifting, de-functioned canals, decay of paleochannels, decline of ground water level, and less replenishing of soils with fresh silts. The present paper is mainly tried to investigate the pre-dam and post-dam hydrogeomorphic variability in relation to flood risk and drawbacks of Damodar Valley Multipurpose Project. Specifically, the annual peak flow of Damodar shifts from August to September due to dam construction and reservoir storage. Applying the annual flood series of log Pearson type III distribution, we have estimated post-dam 5-year peak discharge of above 5,300 m3 s−1 and 100-year flood of above 11,000 m3 s−1. Due to siltation, the bankfull discharges of sample segments are gradually declined up to 4,011 m3 s−1, 2,366 m3 s−1, and 1,542 m3 s−1, respectively, having recurrence interval of 1.18–3.18 years only. With the regulation of monsoon flow, the standard sinuosity index is gradually increased downstream, having high dominance of hydraulic factors in respect of topographic factors. The upstream section of study area (Rhondia to Paikpara) now shows the dominance of aggradational landforms, braiding, avulsion, high width–depth ratio, breaching of right bank, and valley widening, but downstream of Barsul the phenomena of bank erosion, confined sinuosity, low width–depth ratio, and narrowness are more pronounced.

- by Sandipan Ghosh
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- Geography, Human Geography, Environmental Geography, Environmental Science

Flood frequency analysis is a means of understanding the hydrologic characteristics of a stream system. The variation in stream discharge and stream stage (gauge height) are continuously measured and recorded by a hydrograph. An extensive historical record of stream flow provides a means for assessing the flow characteristics by flood frequency and magnitude. Stream flow statistics also provide a means for understanding the nature of the evolution and processes responsible for streams and their encompassing drainage basin.

- by Joann Mossa
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- Botany, Landscape Ecology, Aquatic Ecology, Conservation Biology

<p>The necessity of sustainable development for landscapes has emerged as an important theme in recent decades. Moreover, past landscape reconstruction enables a better understanding of human resilience to climatic and environmental changes in different periods and locations, and illustrates examples of sustainable development in the past. Free and open-source (FOSS) datasets of satellite imagery offer considerable opportunities for landscape heritage stakeholders both for recording and monitoring activities. In this research, a completely FOSS-cloud procedure to enhance the detection of palaeo-landscape features is presented. Sentinel - 2 satellite imagery has been retrieved in the Google Earth Engine dataset collection and analysed through a Python script code realized in Google Colaboratory. A multi-temporal approach has been adopted to investigate the potential of satellite imagery to detect buried features along with Spectral Index (i.e., RGB, False Short Wave Infrared Colour and Bare Soil Index) and Spectral Decomposition analysis (i.e., Hue, Saturation and Value, Tasselled Cap Transformation and Principal Component Analysis). This procedure has been tested in the Po Plain (Northern Italy), chosen because it is characterized by human-landscape interaction since the Mid-Holocene. Thanks to its complex settlement and land-management history, the Po Plain represents an ideal laboratory to assess the potentiality of satellite imagery to enhance riverscapes’ palaeo-features.  The outputs obtained can be visualized directly in the Google Colaboratory browser or downloaded via Google Drive for further graphical applications or spatial analysis. The buried features detected have been checked through the available geomorphological and archaeological literature; published case studies interpreting the occurrence of buried features served as a benchmark to validate the script code developed. This research represents one of the first applications of the GEE Python API in landscape studies. The main advantages of this procedure consist of: i) being FOSS, all the software used here are open-licensed; ii) working in cloud, no powerful hardware is necessary to run the script code; iii) high adaptability, changing the ROI is possible to calculate SI and SD outputs for any area of the world; iv) very basic coding skills are required to adapt the code to a ROI with different environmental characteristics. The development of FOSS-cloud procedures could support the identification, conservation and management of cultural and natural heritage anywhere around the world. In remote areas or where local heritage is threatened as a result of political instability, climate change or other factors, FOSS-cloud protocols can facilitate the application of new scientific methods and enable the dissemination of and access to scientific information.</p>

- by Guillem Domingo-Ribas
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- Computer Science, Landscape Archaeology, Open Source Software, Python
- by David Simm
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- Fluvial Geomorphology
- by Sandipan Ghosh
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- Geography, Environmental Geography, Regional Geography, Physical Geography
- by IOANNIS LIRITZIS
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- Archaeology, Environmental Science, Geoarchaeology, Cultural Heritage
- by Wade Nutter
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- Environmental Engineering, Civil Engineering, Wetlands, Fluvial Geomorphology

El objetivo del presente trabajo es delimitar y describir tramos con pendiente anómalo a lo largo de los principales ríos de la cuenca hidrográfica del Alto Paraná a través del análisis de perfiles longitudinales elaborados con base a modelos digitales de elevación. La cuenca abarca 1.350 km2 y ocupa parte de los departamentos de Alto Paraná y Canindeyu, ubicados en la región este de Paraguay. Los ríos desembocan en el embalse de Itaipú y drenan terrenos formados por basaltos de la Formación Alto Paraná, y de pequeñas áreas de areniscas de las Formaciones Misiones y Acaray. Los tramos de los ríos con declividad anómala son denominados de Zonas de Knickpoints (Zk). Los segmentos fluviales con declividad igual o superior a 0,002 m/m fueron considerados Zk. En total, se identificaron 11 segmentos de Zk con valores medios de longitud, pendiente y amplitud altimétrica igual a 14,17 km, 0,0054 m/m y 74,4 m respectivamente. El suave entallamiento del relieve en la cuenca produjo zonas de knickpoints con pendientes muy bajas en comparación con las Zk encontradas en la margen brasileña del embalse (cuenca del Paraná III), reflejando una evolución geomorfológica diferente del relieve en ambas márgenes del lago.

- by Oscar V I C E N T E Quinonez Fernandez and +1
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- Fluvial Geomorphology
- by Alfredo Ollero
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- Fluvial Processes, Fluvial Geomorphology

Stream channels and flow regimes in the River Kilange catchment reflect a pattern of both natural and anthropogenic disturbances in the riparian corridors. This study examined the channel morphology and stream flow characteristics in three landuse (Urban, Agriculture and Abandoned Agriculture) settings in the River Kilange catchment. Stream channel geometric properties were measured and the derived values used to evaluate the channel parameters were determined through ancillary data and field observation. Channel morphology adjustments and variations in stream flow characteristics were related to the different landuses at riparian level. Metrics for channel morphology and flow characteristics were quantified in 18 sampling units. Pearsons' correlation analysis was applied to determine association between landuse and channel morphology. Students' T-test was used to compare estimated bankfull discharge in the abandoned agriculture landuse category and that of the urban landuse setting. Results revealed both channel widening, increase in wetted-perimeter and bankfull discharge in urban channels. The means of discharge for abandoned-agriculture and urban landuse categories were not equal, signifying increased discharge with increase in human activities. Bivariate linear regression relationship between channel depth and discharge was significant (r =.701, p = 0.035). The result further explained that 42% of the variation of discharge emanated from changes in channel depth. Regressing Cross-sectional area with bankfull discharge also yielded significant relationship (r = .835, p = 0.005), where the regression model explained 65% of the variation. The findings reveal that the identified landuse practices influence stream channel and flow adjustments. Changes in the channel morphology accelerate the river flow process culminating into lateral erosion, flooding and reduction in groundwater recharge. These environmental challenges, if left unchecked could result to land and water resources problems in the area. Therefore, the establishment of forest buffer zone along riparian corridors in the River Kilange catchment is recommended.

- by Ezekiel Yonnana and +1
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- Fluvial Geomorphology

Sandy Springs represents a widely cited, yet poorly understood, Paleoindian archaeological site (~11.5k – 10k RCYBP) located along the Ohio River in southeastern Adams County, Ohio. Little attention has been given to reconstructing the geomorphic history of the surrounding landscape or to the potential that late Quaternary deposits may preserve undocumented Paleoindian components. Preliminary analysis of LiDAR data illustrates that the landscape includes a series of step-like geomorphic surfaces that likely reflect a chronosequence of alluvial/outwash terraces dating from the Late Pleistocene through Holocene. Upper landforms are characterized further by relict eolian sand dunes of undetermined age that reportedly contain archaeological material. Several surficial saline springs also are known to occur in proximity to dune features. LiDAR and NRCS soils data show that dune features rim an oval-shaped low area measuring 2.5 by 0.5 km. Dune formation is especially distinctive on the south-southwestern rim region where it is ~2.4 linear km in length. Dunes display a mixed morphology that appears to include a star-like dune, a possible compound barchan dune, and a possible climbing dune that extends roughly 18 m in height above the surrounding landscape. To what degree dune morphologies are the result of depositional or erosional processes remains unknown. It is proposed that dunes reflect source bordering features associated with increased eolian sedimentation during periods of reduced vegetation cover. Possible causes of vegetation reduction include periods of increased aridity, wildfires, salinization of local water table, or water table drawdown. Finally, it is likely that periods of increased eolian sedimentation resulted in burial of downwind portions of the Paleoindian archaeological component.

- by Matthew Purtill
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- LiDAR, Ohio Valley, Fluvial Geomorphology, Paleoindian archaeology

The drainage basin (watershed) is the fundamental earth surface expression that collects and distributes water and sediment. It follows, the drainage basin is formed by a network of channels (streams) which form the valleys (longitudinal depressions with a gradient approaching some base level elevation) in which they flow. A master or trunk stream forms the principle pathway throughout the basin, and is joined by a number of mutually adjusted branches (tributaries). Therefore, a drainage basin is defined by a trunk stream and the network of channels that connect to it. Each basin may be quantitatively assessed and ordered based upon a hierarchy of stream segments.

Rivers constitute the most important natural water reservoirs from which man derives maximum benefits for economic development. It is therefore not surprising to find most ancient civilizations in the world located around major rivers like the Euphrates, the Tigris and the Nile. This study was undertaken to find out the trends and variability of rainfall and discharge at the River Kilange catchment in Adamawa State, Nigeria. Rainfall and discharge time series data with 27 years observations (1987 to 2013) have been analyzed using the Pearson’s Product Moment Correlation. It was found that mean monthly rainfall and discharge were moderately and positively correlated (r = 0.534, P=0.001). Graphical representation of the data in the study area, however, shows a decreasing trend in the annual mean rainfall, but an increasing trend in the river discharge. Improper land management may have been responsible for the strange phenomenon. It is therefore recommended that appropriate land-use m...

- by Dzarma Sayd
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- Geomorphology, Fluvial Geomorphology

The infrastructure of the original Guapo river dam project at El Guamito site (Miranda state, Venezuela), built and commissioning during the 1975-1977 period, collapsed in December 1999 as a result of the extraordinary rains observed at that time, which generated maximum discharges with magnitudes higher than the design discharge of the work. Therefore, it is necessary to analyze the relationship between the hydrogeomorphological response of the Guapo river basin generated by this extraordinary rains event, the characteristics of the physical and biological media, and the conditions that these determined for the collapse of the dam. Variables of the physical and biological media, in particular climatic and hydrological aspects, were characterized. Morphometric parameters of the basin and its drainage network were measured and calculated. Topographic and geomorphological features were described with the construction of profiles. The physical and biological elements (geology, relief, geomorphology, topography, soil, vegetation, climate, drainage and hydrology) that coexist in the area of the basin have an important influence on the hydrogeomorphological responses of the system (floods, sediment production and haulage and mass movements). The morphometric characteristics of the basin indicate a high correspondence between these aspects and the collapse of the spillway, since they favoured the high discharges that were estimated at the dam site during the occurrence of this adverse event.

- by Williams José Méndez Mata
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- Geomorphology, Hydrology, Venezuela, Fluvial Geomorphology

Present day vegetation patterns in Northwestern Europe are the result of the interaction between the abiotic landscape , human interference, climate and vegetation. Often, palaeovegetation reconstructions are only based on pa-lynological data. When reconstructing past vegetation patterns, the abiotic landscape and archeological data can provide additional and very useful information. Especially, in geomorphological dynamic and heterogeneous areas these data can be used to reconstruct vegetation patterns in between palynological data points. In the Netherlands numerous detailed palaeogeographical maps and a rich archaeological record are available. To use these data for a regional vegetation reconstruction a new interpretative method was developed which reconstructs the distribution of past vegetation communities on the basis of the reconstructed geomorphology. The method is applicable in all regions where there is sufficient information about the abiotic landscape and its development, archaeology and a good coverage of palynological data. The method was applied in a heterogenous Weichselian coversand region, Twente, in the eastern part of the Netherlands and in the dynamic Holocene Rhine-Meuse delta in the central part of the Netherlands. The method is both applicable to visualize long-term vegetation dynamics as short term shifts.

- by Harm Jan Pierik and +1
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- Geomorphology, Palynology, Fluvial Geomorphology, Vegetation History and Archaeobotany
- by Joann Mossa
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- Fluvial Processes, Fluvial Geomorphology

The divers specialised studies of the Bréviandes watermill have yielded precise information on how the milling installation was operated and its environment. It was built with oak posts felled in 1115 along an ancient, silted up meander of the Seine River. The meander was reactivated after cleaning. The foundation probably served to maintain the vanes and platforms of two different mills located to either side of the channel. The millstone fragments correspond to a lower stone and three or four upper stones, two of which retained phytoliths of barley. The lifetime of this facility was probably short, because no repairs were observed following the fire that appears to have provoked the collapse of the north platform.

- by Raphaël Durost and +2
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- Archaeology, Medieval Archaeology, Dendrochronology, Medieval France
- by Christopher Hackney
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- Fluvial Geomorphology, Mekong Studies, Google Earth, Mekong

ABSTRACT: Channel instability and aquatic ecosystem degradation have been linked to watershed imperviousness in humid regions of the U.S. In an effort to provide a more process-based linkage between observed thresholds of aquatic ecosystem degradation and urbanization, standard single event approaches (U.S. Geological Survey Flood Regression Equations and rational) and continuous hydrologic models (HSPF and CASC2D) were used to examine potential changes in flow regime associated with varying levels of watershed imperviousness. The predicted changes in flow parameters were then interpreted in concert with risk-based models of channel form and instability. Although low levels of imperviousness (10 to 20 percent) clearly have the potential to destabilize streams, changes in discharge, and thus stream power, associated with increased impervious area are highly variable and dependent upon watershed-specific conditions. In addition to the storage characteristics of the pre-development watershed, the magnitude of change is sensitive to the connectivity and conveyance of impervious areas as well as the specific characteristics of the receiving channels. Different stream types are likely to exhibit varying degrees and types of instability, depending on entrenchment, relative erodibility of bed and banks, riparian condition, mode of sediment transport (bedload versus suspended load), and proximity to geomorphic thresholds. Nonetheless, simple risk-based analyses of the potential impacts of land use change on aquatic ecosystems have the potential to redirect and improve the effectiveness of watershed management strategies by facilitating the identification of channels that may be most sensitive to changes in stream power.

- by C. Legleiter
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- Remote Sensing, Fluvial Geomorphology, Multidisciplinary, Multispectral

A discussion centering on the pre-history of the upper Wabash Valley in Indiana. Erosional and depositional features expressed throughout the valley from the Ft. Wayne Outlet to Rosedale, Indiana are identified using field reconnaissance, topographic maps, computer-generated terrain models, reference literature, and measured field data.

- by Danny M Vaughn, Ph.D., CMS
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- Geomorphology, Spatial Analysis, Fluvial Geomorphology, Paleohydrology

Fluvial morphology is conditioned by three basic elements: flow regime, sediment yield and valley characteristics. These elements are controlled by factors operating at different spatial and time scales, within and outside of the basin. Moreover, the great influence of human activities has to be considered as they presently constitute one of the main hydromorphological factors. This paper' synthesises the effects of different variables on fluvial morphology and structures the review around the three basic elements mentioned above with examples from the Iberian Peninsula rivers. Understanding the factors that affect channel morphology is of primary importance for assessing river habitat condition, considering that river reach characteristics are the result of the interaction between upstream and downstream catchment and local conditions. Finally, fluvial geomorphology is a key element in river ecosystems that creates geodiversity and heterogeneity of fluvial forms at different spatial scales (i.e., river habitats) and should be considered part of our natural heritage and a valuable natural element itself.

- by Alfredo Ollero and +1
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- Fluvial Geomorphology

Environmental information found in place-names has largely been overlooked by both geoarchaeologists and fluvial geomorphologists in their analysis of the depositional histories of rivers and floodplains. In England, nearly 2000 settlement-names describe some aspect of the fluvial characteristics of their riverine locations. Most of these names were coined during the early medieval period (c.AD500-1100). Among them, a small number indicate places which must have been observed as prone to flooding. High-precision scientific proxies and new sediment dating techniques now make it possible to test the descriptive precision of this c.1000-year-old toponymic record against the long depositional histories of rivers reconstructed from sediment cores. Here, new flood chronologies for the rivers Teme, Severn, and Wye are presented. These have been modelled from stable river sections excavated in three locations—Broadwas, Buildwas, and Rotherwas—connected by the use of the Old English term *wæsse in their names. This term is currently interpreted to mean ‘land by a meandering river which floods and drains quickly’. The results show that in these places (which are geomorphologically distinctive albeit with some variation) the period c. AD350-700 was characterised by more frequent flooding than between AD700-1100, but a greater variation in the sedimentary record during the latter phase suggests more complex flooding regimes including high magnitude single events. This study shows how the toponymic record can potentially provide subtle and precise environmental information helpful in the long-term reconstruction of historic river activity and for our understanding of past human perceptions of riverine environments.

- by Ben Pears and +1
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- Fluvial Geomorphology, Place Names

The term petit âge de glace (PAG) is the literal translation of the English 'Little Ice Age' (LIA). During the past 20 years, the Little Ice Age has emerged as a topic of major research focus spanning such fields as paleoecology, environmental history and climate history (Fig. 1). Despite its widespread usage, no formal definition exists and the term is characterized by a number of ambiguities. Firstly, the Little Ice Age (LIA) was initially used to describe the late 19 th century AD and the glacial floods that impacted the main mountain ranges of both Europe and North America (MATTHEWS and BRIFFA, 2005; WOODWORD, 2014). It was only later that the term was extended to encompass a longer period corresponding to a cold phase in Europe and North America, expressed, for instance, by the expansion of glaciers (LAMBS, 1965; LEROY‑LADURIE, 1967). Although the term was initially used to describe a process, it has gradually acquired a chronological meaning, which has posed some diffi...

lterations in river morphological quality are derived from quantification of human pressures as well as river morphological alteration. Taleghan River is an important source of water for the irrigation of Agri cultural lands in Qazvin Plain. For some economic considerations of Taleghan dam reservoir on the river as well as geology, some reaches of the river have undergone alterations. It seems important to morphological quality assessment in order to planning issues. Our study’s aim is to contribute to the morphological quality evaluation based on a revisited Morphological Quality Index (rMQI) protocol. The rMQI scoring system allows for the quantification of changes when compared to reference conditions. The rMQI corresponds to less than 30%, reflecting a good morphological quality; the rMQI corresponds to more than 30%, reflecting an extremely poor morphological quality. In this context, the paper presents all of the Taleghan River reaches suffer from an extremely poor morphological quality. Causes of degradation are meandering as well as numerous anthropogenic pressures in the upstream part of the basin. In order to revive Taleghan River as well as improve its water quality, preserving and remediating native vegetation, prevention and remediation of land use degradation in upstream's basin as well as river bank erosion control measures can use hard and soft strategies engineering are recommended.

Lo studio sistematico e diacronico di documenti e cartografie inedite d’archivio è necessario per catalogare gli antichi opifici idraulici, attivi fino al secolo scorso sul territorio, come mulini per la macinatura dei cereali, gualchiere per follare i panni di lana, segherie e frantoi ad acqua. Tutte queste strutture si differenziano per la tecnologia dei meccanismi in due categorie: mulini a ruota orizzontale e mulini a ruota verticale. In Basilicata erano presenti entrambe le tecnologie, accomunate dallo stesso sistema di conduzione dell’acqua, una condotta forzata detta torre, o "arubah". I documenti d’archivio hanno permesso di analizzare le caratteristiche costruttive di oltre 800 strutture idrauliche e le principali attività di manutenzione necessarie per il funzionamento costante degli opifici idraulici, di cui ad oggi resta come testimonianza materiale la diffusa presenza di ruderi, accertata anche da rilievi diretti sul campo. Lo studio ha permesso di individuare le caratteristiche del territorio e dei corsi d’acqua maggiormente favorevoli per il posizionamento di un mulino ed ha messo in evidenza le principali cause del danneggiamento delle strutture, dovuto oltre che all’abbandono, anche all’ubicazione dei mulini sul territorio in relazione alle dinamiche fluviali

- by Maria Carmela M C Grano and +1
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- Tourism Studies, Sustainable Tourism, Historical maps, Fluvial Geomorphology