Late Quaternary, palaeohydrology, palaeoecology and floodplain development of the lower River Severn
Late Quaternary, palaeohydrology, palaeoecology and floodplain development of the lower River Severn
Three principal approaches have been taken to the investigation of the Late Quaternary palaeohydrology of the Lower Severn: firstly historical hydrological analysis, secondly the analysis of floodplain sediments and palaeochannels, and thirdly palaeoecological analysis in order to reconstruct floodplain character and catchment conditions. Specific techniques used have included:- the interpretation of stratigraphic data, 14C dating, pollen and diatom analysis, and the multivariate analysis of grain size profiles. During the Late-glacial and early Holocene the channel was of a bedload type carrying high and very variable discharges, but from the late Boreal onwards the channel was of a mixed - to suspended - load type and carried discharges similar to those of today. In historical times changes in mean discharge do not seem to have been as important as a decrease in flow variability. The principal palaeohydrological event of the Holocene was a dramatic increase in suspended sediment production during the early Iron Age. The floodplain underwent rapid vertical accretion often burying a peaty floodplain surface. Palaeoecological analyses of both floodplain and terrace depression sediments have shown that this accretion post-dated the deforestation of the lowland and terrace lime woods and was associated with arable agriculture. Both historical studies and floodplain stratigraphy consistently suggest late Holocene channel planform stability, and it is possible that this is due to rapid overbank accretion and natural levee construction, causing relative channel incision and preventing lateral migration. Within the last 1000 years man has reinforced channel stability and been responsible for decreased floodplain accretion.
University of Southampton
Brown, A. G
550a298a-a479-4e01-a8ff-6e3ed958db16
1982
Brown, A. G
550a298a-a479-4e01-a8ff-6e3ed958db16
Brown, A. G
(1982)
Late Quaternary, palaeohydrology, palaeoecology and floodplain development of the lower River Severn.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
Three principal approaches have been taken to the investigation of the Late Quaternary palaeohydrology of the Lower Severn: firstly historical hydrological analysis, secondly the analysis of floodplain sediments and palaeochannels, and thirdly palaeoecological analysis in order to reconstruct floodplain character and catchment conditions. Specific techniques used have included:- the interpretation of stratigraphic data, 14C dating, pollen and diatom analysis, and the multivariate analysis of grain size profiles. During the Late-glacial and early Holocene the channel was of a bedload type carrying high and very variable discharges, but from the late Boreal onwards the channel was of a mixed - to suspended - load type and carried discharges similar to those of today. In historical times changes in mean discharge do not seem to have been as important as a decrease in flow variability. The principal palaeohydrological event of the Holocene was a dramatic increase in suspended sediment production during the early Iron Age. The floodplain underwent rapid vertical accretion often burying a peaty floodplain surface. Palaeoecological analyses of both floodplain and terrace depression sediments have shown that this accretion post-dated the deforestation of the lowland and terrace lime woods and was associated with arable agriculture. Both historical studies and floodplain stratigraphy consistently suggest late Holocene channel planform stability, and it is possible that this is due to rapid overbank accretion and natural levee construction, causing relative channel incision and preventing lateral migration. Within the last 1000 years man has reinforced channel stability and been responsible for decreased floodplain accretion.
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Published date: 1982
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Local EPrints ID: 460507
URI: http://eprints.soton.ac.uk/id/eprint/460507
PURE UUID: f403d34f-7c3b-46a8-b280-de70087ff947
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Date deposited: 04 Jul 2022 18:23
Last modified: 16 Mar 2024 18:39
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Author:
A. G Brown
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