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Vertical accretion and sediment storage in oxbows and meander cutoffs on the Gatberg River Floodplain, Eastern Cape, South Africa
Thesis (MA)--Stellenbosch University, 2023.
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| Format: | Thesis |
| Language: | English |
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Stellenbosch : Stellenbosch University
2023
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| _version_ | 1867614064388079616 |
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| access_status_str | Open Access |
| author | De Villiers, Zenaria Oriskia |
| author2 | Grenfell, Suzanne |
| author_browse | De Villiers, Zenaria Oriskia Grenfell, Suzanne |
| author_facet | Grenfell, Suzanne De Villiers, Zenaria Oriskia |
| author_sort | De Villiers, Zenaria Oriskia |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MA)--Stellenbosch University, 2023. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/128496 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:46:06.004Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2023 |
| publishDateRange | 2023 |
| publishDateSort | 2023 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/128496 Vertical accretion and sediment storage in oxbows and meander cutoffs on the Gatberg River Floodplain, Eastern Cape, South Africa De Villiers, Zenaria Oriskia Grenfell, Suzanne Stellenbosch University. Faculty of Arts and Social Sciences. Dept. of Geography and Environmental Studies. Oxbows, vertical accretion, lateral accretion, sediment trapping, ecosystem services Thesis (MA)--Stellenbosch University, 2023. Oxbows and meander cutoffs are manifestations of the geomorphological processes that occur in meandering river floodplains. This study investigates the role of oxbows and meander scars as sediment stores in the Gatberg Floodplain in the Eastern Cape, South Africa. The aim of the research was to understand (i) for how long oxbows act as sediment sinks; (ii) what type of sediments accumulate in oxbows; (iii) the impact the type and amount of sediment has on nutrient loading; (iv) which factors control the persistence of oxbows in the landscape, and (v) how this affects their effectiveness as sediment stores. The study made use of several methods, including utilizing aerial photography to measure morphometrics (area, average width, length, diversion angle, radius of curvature) of the oxbows and main channel; a DGPS floodplain survey to characterize the morphology of oxbows and the current channel; sediment cores in selected oxbows to determine vertical variation in particle size, phosphate concentration and organic content, and radiocarbon dating to ascertain the rate of infilling. Results indicate that oxbows have persisted in the floodplain for well over 2000 years, and that the longevity of these features ensures the long-term removal of sediment and associated nutrients. However, given the extremely low rate of infilling ranging between 0.0265- 0.0601 cm/y⁻¹, the importance of these features in terms of phosphate assimilation and sediment trapping ecosystem service provision may have been overstated by ecosystem service assessment tools. Overall, the study presents a range of results to better understand the role oxbows play in trapping and storing sediments. It is the first study in South Africa t¹hat explicitly documents the sediment and phosphate trapping potential of oxbows within floodplain wetlands. Further, it is the first study that uses radiocarbon dating to estimate the rate of infilling of oxbows in South Africa. Masters 2023-03-07T11:26:26Z 2023-08-30T13:13:20Z 2023-03 2023-03-07T11:26:26Z 2023-08-31T09:18:53Z 2023-03-07T11:26:26Z 2023-08-31T09:18:53Z 2023-03 Thesis https://scholar.sun.ac.za/handle/10019.1/128496 en Stellenbosch University application/pdf 94 pages : ill. application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Oxbows, vertical accretion, lateral accretion, sediment trapping, ecosystem services De Villiers, Zenaria Oriskia Vertical accretion and sediment storage in oxbows and meander cutoffs on the Gatberg River Floodplain, Eastern Cape, South Africa |
| title | Vertical accretion and sediment storage in oxbows and meander cutoffs on the Gatberg River Floodplain, Eastern Cape, South Africa |
| title_full | Vertical accretion and sediment storage in oxbows and meander cutoffs on the Gatberg River Floodplain, Eastern Cape, South Africa |
| title_fullStr | Vertical accretion and sediment storage in oxbows and meander cutoffs on the Gatberg River Floodplain, Eastern Cape, South Africa |
| title_full_unstemmed | Vertical accretion and sediment storage in oxbows and meander cutoffs on the Gatberg River Floodplain, Eastern Cape, South Africa |
| title_short | Vertical accretion and sediment storage in oxbows and meander cutoffs on the Gatberg River Floodplain, Eastern Cape, South Africa |
| title_sort | vertical accretion and sediment storage in oxbows and meander cutoffs on the gatberg river floodplain eastern cape south africa |
| topic | Oxbows, vertical accretion, lateral accretion, sediment trapping, ecosystem services |
| url | https://scholar.sun.ac.za/handle/10019.1/128496 |
| work_keys_str_mv | AT devillierszenariaoriskia verticalaccretionandsedimentstorageinoxbowsandmeandercutoffsonthegatbergriverfloodplaineasterncapesouthafrica |