Change search
ReferencesLink to record
Permanent link

Direct link
Geomorphology and landscape evolution of Save River delta, South-central Mozambique
Stockholm University, Faculty of Science, Department of Physical Geography. Universidade Eduardo Mondlane, Moçambique.ORCID iD: 0000-0001-5649-6998
Stockholm University, Faculty of Science, Department of Physical Geography.
Stockholm University, Faculty of Science, Department of Physical Geography.
Stockholm University, Faculty of Science, Department of Physical Geography.
Show others and affiliations
(English)Manuscript (preprint) (Other (popular science, discussion, etc.))
Abstract [en]

The Save River delta has well-preserved geomorphological and sedimentological features with potential to reveal its evolution as well as past regional environmental changes, which are anticipated to integrate into other data at a global scale. In this study we mapped and integrated these features to understand the environmental processes that drove the late evolution of the delta. The results suggest that the present configuration of the delta was primarily dominated by a delta-front protruding into the sea, in a faulted coast section that may have favoured the formation of the depocenter. The development of the delta-front was initiated prior to c. 3100 cal. yrs BP, and around this age, fine-grained sediments started to accumulate on it forming a mangrove wetland deposit that expanded from the proximal sector of the delta to the current position shown in a geomorphological map. The results show successive dune ridges in the southern sector of the delta which indicate a series of consecutive shorelines over time as the delta prograded towards the current position. These dunes have created favourable conditions for accumulation of fine-grained sediments in the back-barrier sectors, contributing to the development of the mangrove wetland. An alluvial floodplain developed during the last millennium, probably a result of high precipitation the catchment area.

Keyword [en]
Delta evolution, Save River delta, mangrove wetland, delta progradation, Mozambique coast, coastal dunes
National Category
Physical Geography
Research subject
Physical Geography
Identifiers
URN: urn:nbn:se:su:diva-126049OAI: oai:DiVA.org:su-126049DiVA: diva2:897046
Available from: 2016-01-24 Created: 2016-01-24 Last updated: 2016-01-28Bibliographically approved
In thesis
1. Geomorphology and environmental dynamics in Save River delta, Mozambique: A cross-timescale perspective
Open this publication in new window or tab >>Geomorphology and environmental dynamics in Save River delta, Mozambique: A cross-timescale perspective
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Long-term perspectives on the evolution of river deltas have provided useful knowledge capable of responding to pending questions related to the ongoing climate and environmental changes. Increasing utilization pressure on delta environments has necessitated increased attention to protect the socio-economic and ecological values. As a result, multiple local initiatives have been designed, aimed at mitigating environmental deterioration and implementing adaptive measures, but many such initiatives have shown limited success. This thesis uses a case study of Save River delta in Mozambique to explore the relation between geomorphological evolution and socio-ecological system dynamics in delta environments. In addition, key environmental variables that concern the society today are highlighted and discussed in a management perspective. The results of the study show the development of Save River delta from the mid-Holocene to the present. The geomorphological settings of the delta suggest a faulted coastline over which subsequent deposition of fluvial sediments has formed a protruding delta front. Between c. 3000 and 1300 years ago, fine-grained sediments accumulated on top of the delta-front in the proximal part of the delta. This type of material was deposited under intertidal conditions and supported the formation of mangrove habitat. The geographical distribution of the mangrove deposit was driven by successive stages of back-barrier swamp formation and sea-level change as the delta evolved. From c. 1300 years ago, the river delta started to receive fluvial sediments from pulses of floods forming an alluvial floodplain. These sediments have accumulated mainly on the fine-grained mangrove wetland deposit. All the geomorphological features have evolved in a shoreward-shifting pattern over time. Centennial to decadal changes observed in the delta have followed a predictable geomorphological pattern, which is also part of the millennial evolution. The mangrove system, the base for the socio-economic system, is consequently strongly affected by the geomorphological development of the area. An increasing sensitivity of socio-ecological systems to environmental stressors, e.g. floods, cyclones and erosion, has motivated multiple initiatives to work towards a sustainable management of delta environments. This thesis highlights the need for interplay between geomorphology and ecology, considering both long- and short-term dynamics of delta environments. Hitherto, management initiatives have been concentrated on fragmented interventions of controlling water flow, which have disrupted the natural dynamics by obstructing the sedimentation-erosion cycle. To change this trend, coastal planners need to consider the significance of natural processes, e.g. cyclones, floods, erosion and accretion, for the long-term ecological and social sustainability of delta environments.

Place, publisher, year, edition, pages
Stockholm: Department of Physical Geography, Stockholm University, 2016. 35 p.
Series
Dissertations from the Department of Physical Geography, ISSN 1653-7211 ; 53
Series
, Dissertations from the Department of Physical Geography, ISSN 1653-7211 ; No 53
Keyword
Save River delta, deltaic wetlands, biogeomorphology, climate change, landscape evolution, coastal management, socio-ecological systems
National Category
Physical Geography Geology
Research subject
Physical Geography
Identifiers
urn:nbn:se:su:diva-126064 (URN)978-91-7649-311-3 (ISBN)
Public defence
2016-03-11, De Geersalen, Geovetenskapens hus, Svante Arrhenius väg 14, Stockholm, 13:00 (English)
Opponent
Supervisors
Funder
Sida - Swedish International Development Cooperation Agency, Decision No. 2011-002102
Note

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: Manuscript. Paper 2. Manuscript. Paper 3: Manuscript. Paper 4: Manuscript.

Available from: 2016-02-17 Created: 2016-01-24 Last updated: 2016-02-08Bibliographically approved

Open Access in DiVA

No full text

Search in DiVA

By author/editor
Massuanganhe, ElidioWesterberg, Lars-OveRisberg, JanPreusser, FrankBjursäter, Stefan
By organisation
Department of Physical Geography
Physical Geography

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 42 hits
ReferencesLink to record
Permanent link

Direct link