Surficial geological tools in fluvial geomorphology

Jacobson, Robert B.; O'Connor, J. E.; Oguchi, Takashi

doi:10.1002/9781118648551.ch2

Cited by 10 publications

(5 citation statements)

References 123 publications

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“…To close the concept, we define the flood stage as an established gauge height for a given location above which a rise in water surface level begins to create a hazard [5]. We identified it with the bankfull stage from the proto-floodplain (top of the point bar surface) that supports woody vegetation [49].…”

Section: Effects Of Vegetation Encroachment and Aggradation On Channementioning

confidence: 99%

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100 Years of Competition between Reduction in Channel Capacity and Streamflow during Floods in the Guadalquivir River (Southern Spain)

Bohorquez

Moral-Erencia

2017

Remote Sensing

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Reduction in channel capacity can trigger an increase in flood hazard over time. It represents a geomorphic driver that competes against its hydrologic counterpart where streamflow decreases. We show that this situation arose in the Guadalquivir River (Southern Spain) after impoundment. We identify the physical parameters that raised flood hazard in the period 1997-2013 with respect to past years 1910-1996 and quantify their effects by accounting for temporal trends in both streamflow and channel capacity. First, we collect historical hydrological data to lengthen records of extreme flooding events since 1910. Next, inundated areas and grade lines across a 70 km stretch of up to 2 km wide floodplain are delimited from Landsat and TerraSAR-X satellite images of the most recent floods (2009-2013). Flooded areas are also computed using standard two-dimensional Saint-Venant equations. Simulated stages are verified locally and across the whole domain with collected hydrological data and satellite images, respectively. The thoughtful analysis of flooding and geomorphic dynamics over multi-decadal timescales illustrates that non-stationary channel adaptation to river impoundment decreased channel capacity and increased flood hazard. Previous to channel squeezing and pre-vegetation encroachment, river discharges as high as 1450 m 3 •s −1 (the year 1924) were required to inundate the same areas as the 790 m 3 •s −1 streamflow for recent floods (the year 2010). We conclude that future projections of one-in-a-century river floods need to include geomorphic drivers as they compete with the reduction of peak discharges under the current climate change scenario.

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Section: Effects Of Vegetation Encroachment and Aggradation On Channementioning

confidence: 99%

“…Table A1 summarises the characteristic dimensions of the meanders in Figure 1. To evaluate them, we determined the bankfull stage from the proto-floodplain (top of the point bar surface) that supports woody vegetation, as suggested in [49]. Table A1.…”

Section: Conflicts Of Interestmentioning

confidence: 99%

100 Years of Competition between Reduction in Channel Capacity and Streamflow during Floods in the Guadalquivir River (Southern Spain)

Bohorquez

Moral-Erencia

2017

Remote Sensing

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“…Chronosequence frameworks have improved understanding of the rates and pathways of primary mineral weathering [4,5], clay mineral transformations [6,7], and changes to bulk chemistry [8,9] in soils from a range of global settings. Furthermore, when the time required to develop certain pedogenic features is known, soil chemical and mineralogical properties are useful for establishing relative-age relationships among landforms [5,10], mapping and correlating Quaternary deposits [11], and aiding chronological interpretations in archaeological investigations [12,13]. Given these attributes, soil chronosequences serve important functions in pedology, geomorphology, archaeology, and Quaternary geology [3].…”

Section: Introductionmentioning

confidence: 99%

Soil Chemistry and Clay Mineralogy of an Alluvial Chronosequence from the North Carolina Sandhills of the Upper Coastal Plain, USA

2021

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Temporal changes in soil development were assessed on fluvial terraces of the Little River in the upper Coastal Plain of North Carolina. We examined five profiles from each of six surfaces spanning about 100,000 years. Soil-age relationships were evaluated with inter-surface clay mineral comparisons and regression of chemical properties versus previously reported optically-stimulated luminescence ages using the most developed subsoil horizon per profile. Bases to alumina (Bases/Al2O3) ratios have negative correlations with age, whereas dithionite-Fe (FeD) concentrations are positively correlated with time and differentiate floodplain (<200 yr BP) from terrace (≥10 ± 2 ka) soils and T4 pedons (75 ± 10 ka) from younger (T1-T3b, 10 ± 2–55 ± 15 ka) and older (T5b, 94 ± 16 ka) profiles. Entisols develop into Ultisols with exponentially decreasing Bases/Al2O3 ratios, reflecting rapid weatherable mineral depletion and alumina enrichment during argillic horizon development in the first 13–21 kyr of pedogenesis. Increasing FeD represents transformation and illuviation of free Fe inherited from parent sediments. Within ~80–110 kyr, a mixed clay mineral assemblage becomes dominated by kaolinite and gibbsite. Argillic horizons form by illuviation, secondary mineral transformations, and potentially, a bioturbation-translocation mechanism, in which clays distributed within generally sandy deposits are transported to surface horizons by ants and termites and later illuviated to subsoils. T5b profiles have FeD concentrations similar to, and gibbsite abundances greater than, those of pedons on 0.6–1.6 Ma terraces along Coastal Plain rivers that also drain the Appalachian Piedmont. This is likely because the greater permeability and lower weatherable mineral contents of sandy, Coastal Plain-sourced Little River alluvium favor more rapid weathering, gibbsite formation, and Fe translocation than the finer-grained, mineralogically mixed sediments of Piedmont-draining rivers. Therefore, recognizing provenance-related textural and mineralogical distinctions is crucial for evaluating regional chronosequences.

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“…Apesar de ser comumente tratada como subárea da Geografi a, ela demanda (e ao mesmo tempo fornece) conhecimentos da Geologia, Biologia e engenharias, entre outras ciências, o que revela sua diversidade e amplitude. Questões relativas à dinâmica fl uvial podem envolver uma grande variedade de escalas temporais -segundos a eras geológicas -e espaciais -de manchas individuais de habitats à evolução de bacias de drenagem de escala continental (Jacobson et al, 2003).…”

Section: Introductionunclassified

“…Assim, a interpretação do passado e da história geomorfológica (em termos evolutivos) dos cursos d'água e da rede de drenagem seria embasada pelas evidências atuais, principalmente as características dos registros sedimentares. Por outro lado, uma compreensão do passado pode ser a chave para se entender o futuro, no sentido de que a história de um sistema fl uvial pode fornecer subsídios para a compreensão das características naturais de um curso d'água e, dessa forma, servir como referencial para avaliações, restaurações e previsões (Jacobson et al, 2003), trazendo inúmeros benefícios e possibilidades para o planejamento territorial e manejo de sistemas hídricos.…”

Section: Introductionunclassified

A Produção Científica Em Geomorfologia Fluvial Na Revista Brasileira De Geomorfologia: Panorama Bibliográfico, Tendências E Lacunas

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Reis

2019

Rev. Bras. Geomorfol.

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Em levantamentos sobre a produção científica brasileira no século XXI, a Geomorfologia Fluvial é quase sempre apontada como o ramo da Geomorfologia com o maior número de publicações. Nesse sentido, cabe detalhar a Geomorfologia Fluvial produzida nas últimas décadas no país, contribuindo para a análise de sua evolução como ramo da ciência. Assim, o presente trabalho analisa as publicações sobre Geomorfologia Fluvial na Revista Brasileira de Geomorfologia (RBG), o único periódico nacional especializado nesta área do conhecimento. Foi feito um levantamento nas 49 edições da RBG entre os anos de 2000 e 2018 e a caracterização dos trabalhos quanto aos subtemas, autoria, instituições de origem, além de palavras-chave, recortes espaciais e abordagens técnico-metodológicas mais frequentes. Ao todo, foram analisadas 167 publicações envolvendo o estudo de sistemas fluviais e seus elementos. Os resultados mostram que ocorreu um crescimento consistente no número de publicações sobre Geomorfologia Fluvial. Há grande variedade de autores, coautores e centros de referência, com destaque para instituições federais de ensino superior das regiões sudeste e sul. A região hidrográfica do Paraná concentra o maior número de publicações, seguida pelas regiões hidrográficas do Atlântico Sudeste e São Francisco. Os principais subtemas se referem à morfologia de sistemas fluviais e/ou sua transformação, à dinâmica e/ou modelagem hidrossedimentológica e à morfometria de sistemas fluviais. Dentre centenas de palavras-chave utilizadas, as de maior recorrência foram “Geomorfologia Fluvial”, “Neotectônica”, “Luminescência Opticamente Estimulada”, “Rio Paraná” e “Sensoriamento remoto”. Em consonância com os dois últimos apontamentos, as abordagens técnico-metodológicas mais empregadas se referem à análise de dados topográficos, de imagens de satélite, aplicações de geoprocessamento e análise de variáveis e dados hidrossedimentológicos. Ressalta-se uma dominância de estudos com análise em escalas mais abrangentes, envolvendo bacias hidrográficas (ou um conjunto delas) e unidades de relevo. Outro recorte espacial comum é o trecho fluvial. Porém, há certa carência de estudos mais localizados, focados em sistemas de cabeceiras de drenagem e nascentes.

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Surficial geological tools in fluvial geomorphology

Cited by 10 publications

References 123 publications

100 Years of Competition between Reduction in Channel Capacity and Streamflow during Floods in the Guadalquivir River (Southern Spain)

100 Years of Competition between Reduction in Channel Capacity and Streamflow during Floods in the Guadalquivir River (Southern Spain)

Soil Chemistry and Clay Mineralogy of an Alluvial Chronosequence from the North Carolina Sandhills of the Upper Coastal Plain, USA

A Produção Científica Em Geomorfologia Fluvial Na Revista Brasileira De Geomorfologia: Panorama Bibliográfico, Tendências E Lacunas

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