Delta Challenges and Trade-Offs from the Holocene to the Anthropocene

Nicholls, Robert J.; Adger, W. Neil; Hutton, Craig; Hanson, Susan

doi:10.1007/978-3-030-23517-8_1

Cited by 18 publications

(25 citation statements)

References 37 publications

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“…These results could be used for designing a river management plan to reduce the risk of droughts and preventing or mitigating SWI. This study highlights the future effects on deltas, which are hotspot for climate change vulnerability and impacts of human activity, if climate change will not be reduced and if new sustainable socio‐economic policies for coasts will not be established (Arto et al., 2020; Nicholls, Adger, Hutton, & Hanson, 2020).…”

Section: Discussionmentioning

confidence: 99%

“…Delta regions have also been widely identified as global hotspots of vulnerability to climate change and at risk (Hill et al., 2020; Nicholls, Adger, Hutton, & Hanson, 2020; Nicholls, Adger, Hutton, Hanson, Lazar, et al., 2020). With sea level rising as a consequence of global warming, SWI is a growing risk in coastal zones (Nicholls & Cazenave, 2010).…”

Section: Introductionmentioning

confidence: 99%

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Saltwater Intrusion in a Mediterranean Delta Under a Changing Climate

et al. 2021

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Coastal zones are dynamic and sensitive to changing forcing conditions related to climate variability, such as flooding and droughts, storm surges, and sea-level changes. Among coastal systems, deltas and estuaries are characterized by complex dynamics between fresh water of continental origin and salt waters (Horner-Devine et al., 2015; Valle-Levinson, 2010). Moreover, deltas are impacted by human activities and in some cases the anthropic control on the natural environment can override the climatic signal, forcing deltas toward a man-made river-dominated system (Maselli & Trincardi, 2013). One of the major problems affecting deltas and estuaries, especially during drought conditions, is the upstream extent of the mixing zone between freshwater and saltwater. This would lead to a consequent increase of the salt content in aquifers and surface waters. Saltwater intrusion (SWI) in rivers can hinder the use of surface water for irrigation or drinking purposes and can threaten the livelihood of coastal communities that rely on fresh water supplies for their livelihood. Furthermore, when there is contact between the channel bed and the underlying coastal aquifer, saltwater can intrude and lead to salinization of soils (Werner et al., 2013; White & Kaplan, 2017). A variety of factors drives SWI on different spatial and temporal scales. These can be natural (sea level, storm surges, hurricanes, climate fluctuations, and subsidence) or anthropogenic (land drainage, exploitation of coastal aquifers, reduction in freshwater discharge from hydropower production and irrigation, interbasin diversions and other hydraulic infrastructures, changes in land-use within the drainage basin and channel deepening), as well as combinations of both (White & Kaplan, 2017). Therefore, understanding the processes controlling SWI and their effects under climate change is crucial for defining proper coastal mitigation and management strategies.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Saltwater Intrusion in a Mediterranean Delta Under a Changing Climate

et al. 2021

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“…Large river deltas worldwide are ecologically challenged by the interacting forces of sea‐level rise, subsidence, and human development (Brown & Nicholls, 2015; Nicholls et al, 2020). These deltas are formed by large rivers such as the Amazon, Ganges/Brahmaputra, Indus, Mekong, Nile, Volta, and the Mississippi/Atchafalaya that carry and deposit high loads of sediment.…”

Section: Introductionmentioning

confidence: 99%

Hydrologic modification and channel evolution degrades connectivity on the Atchafalaya River floodplain

Kroes

Demas

Allen³

et al. 2022

Earth Surf Processes Landf

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The Atchafalaya River Basin is the largest remaining forested wetland in the contiguous United States. Since 1960, dredging and channel erosion in the Basin have resulted in changes to the hydrologic connectivity that have not been quantified. Analyses were conducted to determine the hydraulic and geomorphic factors that have changed since discharge became controlled that may have decreased river/floodplain connectivity. We examined: (1) stage/discharge relationships from 1960 to 2014; (2) hydroperiods across the floodplain; (3) discharge distribution to the floodplain by comparing discharge measurements from 1959–1968 to 2005–2012; and (4) channel cross‐sections and floodplain elevations. Our results indicate that much of the floodplain no longer receives headwater discharge (upstream to downstream, > 200 km2) or receives too little discharge to alleviate stagnancy and hypoxia in the forested wetland at lower stages. Large portions of the Basin (400 km2) have low water levels controlled by channel geomorphology and sea‐level rise that inundate the forested floodplain for more than 50% of the calendar year. This extended duration of inundation contributes to hypoxia and likely reduces nutrient retention. The confinement of discharge to a large efficient channel compromises the ability of this system to respond to sea‐level rise and subsidence. This study provides insight to the effects of flood management projects along Coastal Plain rivers and deltas.

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“…Deltas are of critical socioeconomic and ecological importance, and are inhabited by about half a billion of the world's population [1]. Located at the interface between land and sea, deltas are significantly affected by climate change and intensive anthropogenic activities, such as sea-level increases, storm surges and upstream dam regulation [1][2][3]. It is well-recognized that dam regulation causes hydrological alteration [4][5][6] and morphological evolution of the world's deltas [7,8].…”

Section: Introductionmentioning

confidence: 99%

“…It is well-recognized that dam regulation causes hydrological alteration [4][5][6] and morphological evolution of the world's deltas [7,8]. Given the continuously increasing coastal erosion and degradation of deltaic ecosystems in this rapidly changing environment of the Anthropocene [3,[9][10][11][12], understanding effects of dam regulation that lead to the hydrological alteration and morphological evolution of the world's deltas is an imperative task.…”

Section: Introductionmentioning

confidence: 99%

A Tale of Two Deltas: Dam-Induced Hydro-Morphological Evolution of the Volta River Delta (Ghana) and Yellow River Delta (China)

Gao

Shao

et al. 2021

Water

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Previous studies mostly focus on an individual delta, or deltas at a global scale, to explore dam effects on deltaic hydrological alteration and morphological evolution, while comparative studies on selected similar deltas remain scarce. In this study, we compare the alteration of river discharge and sediment load, as well as the associated deltaic area and shoreline, of two deltas, namely, the Volta River Delta in Ghana and the Yellow River Delta in China, which are subject to similar forcings and mainstem dam influences. The results show that the sediment loads of the Volta River Delta and Yellow River Delta have decreased abruptly and gradually, respectively, to ~10% of the pre-dam level, presumably due to differences in reservoir capacity and upstream dam location. Sediment decline has led to a decrease of the fluvial dominance ratio, which has also been affected by the river mouth location and shoreline orientation. As a consequence, the area of the Volta River Delta has shifted to a new quasi-equilibrium, whereas the Yellow River Delta has kept prograding. This comparative study provides references for understanding the future evolution of similar deltas around the world.

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Delta Challenges and Trade-Offs from the Holocene to the Anthropocene

Cited by 18 publications

References 37 publications

Saltwater Intrusion in a Mediterranean Delta Under a Changing Climate

Saltwater Intrusion in a Mediterranean Delta Under a Changing Climate

Hydrologic modification and channel evolution degrades connectivity on the Atchafalaya River floodplain

A Tale of Two Deltas: Dam-Induced Hydro-Morphological Evolution of the Volta River Delta (Ghana) and Yellow River Delta (China)

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