Temporal and spatial adjustments of channel migration and planform geometry: Responses to ENSO driven climate anomalies on the tropical freely-meandering Aguapeí River, São Paulo, Brazil
Two reaches of Aguapeí River, a left-bank tributary of the Paraná River in western São Paulo state, Brazil, were studied with the objective of assessing the role of bend curvature on channel migration in this wet-tropical system and examining if land-use changes or ENSO (El Niño Southern Oscillation...
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ftunivwollongong:oai:ro.uow.edu.au:smhpapers-6308 2023-05-15T18:28:37+02:00 Temporal and spatial adjustments of channel migration and planform geometry: Responses to ENSO driven climate anomalies on the tropical freely-meandering Aguapeí River, São Paulo, Brazil Suizu, Taina Nanson, Gerald C 2018-01-01T08:00:00Z https://ro.uow.edu.au/smhpapers/5254 unknown Research Online https://ro.uow.edu.au/smhpapers/5254 Faculty of Science, Medicine and Health - Papers: part A Medicine and Health Sciences Social and Behavioral Sciences article 2018 ftunivwollongong 2020-02-25T12:05:56Z Two reaches of Aguapeí River, a left-bank tributary of the Paraná River in western São Paulo state, Brazil, were studied with the objective of assessing the role of bend curvature on channel migration in this wet-tropical system and examining if land-use changes or ENSO (El Niño Southern Oscillation) driven climate anomalies over nearly half a century have changed migration behaviour and planform geometry. Meander-bend migration rates and morphometric parameters including meander-bend curvature, sinuosity, meander wavelength and channel width, were measured and the frequency of bend cutoffs was analysed in order to determine the rate of change of channel adjustment over a 48year period to 2010. Results show that maximum average channel migration rates occur in bends with curvatures of about 2-3 r c /w, similar to other previously studied temperate and subarctic freely meandering rivers although not as pronounced and with a tendency to favour tighter curvature. From 1962 to 2010 the Aguapeí River has undergone a significant reduction in sinuosity, a shift from tightly curving to more open bends, an overall decline in channel migration rates, an associated decrease in the frequency of neck-cutoffs and an overall increase in channel width. As the majority of the drainage basin (96%) was already deforested in 1962, channel form and process changes were, unlike an interpretation for an adjacent river system, not attributed to altered land-use but rather to a sharp ENSO-driven increase in the magnitude of peak flow-discharges of some 32% since 1972. In summary, this research revealed that recent climate and associated flow regime changes are having a pronounced effect on river channel behaviour in the Aguapeí River investigated here. Article in Journal/Newspaper Subarctic University of Wollongong, Australia: Research Online |
institution |
Open Polar |
collection |
University of Wollongong, Australia: Research Online |
op_collection_id |
ftunivwollongong |
language |
unknown |
topic |
Medicine and Health Sciences Social and Behavioral Sciences |
spellingShingle |
Medicine and Health Sciences Social and Behavioral Sciences Suizu, Taina Nanson, Gerald C Temporal and spatial adjustments of channel migration and planform geometry: Responses to ENSO driven climate anomalies on the tropical freely-meandering Aguapeí River, São Paulo, Brazil |
topic_facet |
Medicine and Health Sciences Social and Behavioral Sciences |
description |
Two reaches of Aguapeí River, a left-bank tributary of the Paraná River in western São Paulo state, Brazil, were studied with the objective of assessing the role of bend curvature on channel migration in this wet-tropical system and examining if land-use changes or ENSO (El Niño Southern Oscillation) driven climate anomalies over nearly half a century have changed migration behaviour and planform geometry. Meander-bend migration rates and morphometric parameters including meander-bend curvature, sinuosity, meander wavelength and channel width, were measured and the frequency of bend cutoffs was analysed in order to determine the rate of change of channel adjustment over a 48year period to 2010. Results show that maximum average channel migration rates occur in bends with curvatures of about 2-3 r c /w, similar to other previously studied temperate and subarctic freely meandering rivers although not as pronounced and with a tendency to favour tighter curvature. From 1962 to 2010 the Aguapeí River has undergone a significant reduction in sinuosity, a shift from tightly curving to more open bends, an overall decline in channel migration rates, an associated decrease in the frequency of neck-cutoffs and an overall increase in channel width. As the majority of the drainage basin (96%) was already deforested in 1962, channel form and process changes were, unlike an interpretation for an adjacent river system, not attributed to altered land-use but rather to a sharp ENSO-driven increase in the magnitude of peak flow-discharges of some 32% since 1972. In summary, this research revealed that recent climate and associated flow regime changes are having a pronounced effect on river channel behaviour in the Aguapeí River investigated here. |
format |
Article in Journal/Newspaper |
author |
Suizu, Taina Nanson, Gerald C |
author_facet |
Suizu, Taina Nanson, Gerald C |
author_sort |
Suizu, Taina |
title |
Temporal and spatial adjustments of channel migration and planform geometry: Responses to ENSO driven climate anomalies on the tropical freely-meandering Aguapeí River, São Paulo, Brazil |
title_short |
Temporal and spatial adjustments of channel migration and planform geometry: Responses to ENSO driven climate anomalies on the tropical freely-meandering Aguapeí River, São Paulo, Brazil |
title_full |
Temporal and spatial adjustments of channel migration and planform geometry: Responses to ENSO driven climate anomalies on the tropical freely-meandering Aguapeí River, São Paulo, Brazil |
title_fullStr |
Temporal and spatial adjustments of channel migration and planform geometry: Responses to ENSO driven climate anomalies on the tropical freely-meandering Aguapeí River, São Paulo, Brazil |
title_full_unstemmed |
Temporal and spatial adjustments of channel migration and planform geometry: Responses to ENSO driven climate anomalies on the tropical freely-meandering Aguapeí River, São Paulo, Brazil |
title_sort |
temporal and spatial adjustments of channel migration and planform geometry: responses to enso driven climate anomalies on the tropical freely-meandering aguapeí river, são paulo, brazil |
publisher |
Research Online |
publishDate |
2018 |
url |
https://ro.uow.edu.au/smhpapers/5254 |
genre |
Subarctic |
genre_facet |
Subarctic |
op_source |
Faculty of Science, Medicine and Health - Papers: part A |
op_relation |
https://ro.uow.edu.au/smhpapers/5254 |
_version_ |
1766211167118688256 |