Evolution from estuary to delta: Alluvial plain morphology and sedimentary characteristics of the Shoalhaven River mouth, southeastern Australia

Carvalho, Rafael Cabral; Woodroffe, Colin D.

doi:10.1016/j.ecss.2020.106857

Cited by 22 publications

(2 citation statements)

References 47 publications

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“…The abundance of gravel in the fluvial and flood-tide deltas prevented sampling of their subsurface and therefore their relationship with potentially underlying central basin facies is unknown. Traditionally, fluvial deltas prograde into an estuary progressively burying central basin units, and eventually deliver sediment directly to the open coast (Roy, 1984) such as observed in the Shoalhaven River in eastern Australia (Carvalho and Woodroffe, 2020; Umitsu et al, 2001). In Parapara Inlet, based on the sedimentology and radiocarbon evidence, the fluvial delta progressively extended into the estuary until around 4.8 ka.…”

Section: Discussionmentioning

confidence: 99%

Holocene sea-level change and estuary infill in North West Nelson, central New Zealand

2021

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The sedimentary sequences found within estuaries in the north west Nelson region of central New Zealand are investigated in order to quantify the timing of the end of the Post Glacial Marine Transgression. This region has been identified as being relatively stable in terms of vertical tectonic movement during the Holocene, but is yet to yield any reconstructions of eustatic sea level. In this study, we investigate the Holocene infill of a barrier estuary (Parapara Inlet) through sedimentological analysis and radiocarbon dating of 18 vibracores up to 4.2 m in length. It is found that the estuary infilled through a combination of lateral flood tide and fluvial delta progradation as well as vertical central basin infill. The central basin infilled at a consistent rate of 0.4 mm/year in both the mid (7.0–6.0 ka) and late-Holocene (2.5–1.5 ka). By the time of early human (Maori) settlement (c. 1 ka), the estuary surface was at low intertidal elevations with sediment being transported from the fluvial to tidal delta. A discernible change in sedimentation rates could not be associated with Maori settlement; however, infill rates increased to at least 12.5 mm/year in the past 150 years due hydraulic sluicing associated with mining. The sedimentary history of Parapara Inlet is compared to nearby Whanganui Inlet, d’Urville Island and Nelson to establish the character of regional Holocene sea level movement. It is found that relative sea level reached modern elevations between 8 and 7 ka in the region. The similarity between sea level curves for the end of the post glacial marine transgression (PMT) to other tectonically stable sites in northern New Zealand suggests that this curve can now be considered a true eustatic signal for the New Zealand archipelago.

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Section: Discussionmentioning

confidence: 99%

Holocene sea-level change and estuary infill in North West Nelson, central New Zealand

2021

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“…Yuin, Gundungurra and other Indigenous nations are connected to each other by the Shoalhaven River. The river is also a significant place for ecologists and other scientists who identify it as a place of high water and sediment movement, and full of aquatic life (Carvalho and Woodroffe, 2020). The river is constantly evolving and becoming anew as it responds to the rain, the ocean tides, the plants that grow along its banks and the humans and animals that live alongside and within it.…”

Section: Observation: the Snakementioning

confidence: 99%

‘Often in between’: Thinking through research methods and Indigenous sovereignty with Yuin Country

Arnold

Atchison

McKnight

2023

Environment and Planning F

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Indigenous scholars have been calling for renewed attention to the theorisation and practice of sovereignty, including within research. Their scholarship has drawn attention to the sovereignty of people within research processes, as well as diverse expressions of sovereignty. In this article we bring these two dimensions into conversation to consider how research methods might enable and enliven understandings and practices of sovereignty within geography. Illustrating Yuin approaches to research through poetry, observation and dreaming, we show how Country is a living enactment of sovereignty. It dynamically contributes to research processes and enables nonhuman entities to communicate within and beyond their territory as sovereign subjects. In particular, Yuin research methods acknowledge the significant contribution of plants in the theorisation~storying and practice of sovereign Country. Through plants, we come to develop a knowledge of sovereign Country as often in between things, including places and knowledges, vulnerability and protection, and removal and persistence. Such insights are respectfully offered here in the spirit of broadening disciplinary perspectives and capacities in order to revitalise research that addresses the relationships between territory and its people.

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Sediment dynamics at different timescales on an embayed coast in southeastern Australia

et al. 2022

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The concept of coastal sediment compartments has recently been adopted at a national scale in Australia to better understand sediment and shoreline dynamics and to underpin management of future shoreline behaviour in response to impacts of climate change. Geomorphological studies in southern NSW have provided a foundation for development of conceptual models of estuary and sandy barrier evolution. Geochronological reconstructions using radiocarbon, optically-stimulated luminescence, and other dating techniques, reviewed in this paper, demonstrate that adjacent compartments are at successive stages. Three compartments, Illawarra, Shoalhaven and Moruya, are compared, each with different catchment characteristics and different levels of human intervention. Landform change and sediment accumulation at millennial timescales enable estimates of past sediment accretion (vertical accumulation) and horizontal displacement of shorelines (particularly progradation), as a first step towards quantifying volumetric changes of morphology. Lake Illawarra is a barrier estuary at an early stage of infill, but land-use change, urbanisation, and engineering structures at the entrance have accelerated rates of sediment accumulation. The Shoalhaven River has infilled its estuary and delivers sand to the coast. It has been subject to several conspicuous anthropogenic interventions. At Moruya, ongoing supply of sand, primarily from offshore rather than from the catchment, has resulted in beach-ridge plains (strandplains) with changes in their alongshore inter-connectivity driven by differential embayment infilling. Millennial-scale geomorphology indicates landform change providing a means to determine natural trajectories of sediment transfer. However, variability is apparent at century and decadal timescales, compounded by various anthropogenic interventions. Disentangling natural and anthropogenic influences will be necessary to provide greater confidence in estimating past and present sediment budgets. Assessing sand sources and transport rates is important in relation to engineering interventions at entrances, and long-term resilience of coastal habitats. Such issues are the focus of coastal management programs, and this synthesis emphasises the relevance of a sediment budget approach to understand contemporary sediment pathways and provide an indication of future response to engineering interventions and sensitivity to climate change.

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Evolution from estuary to delta: Alluvial plain morphology and sedimentary characteristics of the Shoalhaven River mouth, southeastern Australia

Cited by 22 publications

References 47 publications

Holocene sea-level change and estuary infill in North West Nelson, central New Zealand

Holocene sea-level change and estuary infill in North West Nelson, central New Zealand

‘Often in between’: Thinking through research methods and Indigenous sovereignty with Yuin Country

Sediment dynamics at different timescales on an embayed coast in southeastern Australia

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