Post-glacial range of variability in the Conejos River Valley, southern Colorado, USA: fluvial response to climate change and sediment supply

AbstractIn Humboldt Bay, tectonic subsidence exacerbates sea-level rise (SLR). To build surface elevations and to keep pace with SLR, the sediment demand created by subsidence and SLR must be balanced by an adequate sediment supply. This study used an ensemble of plausible future scenarios to predict potential climate change impacts on suspended-sediment discharge (Qss) from fluvial sources. Streamflow was simulated using a deterministic water-balance model, and Qss was computed using statistical sediment-transport models. Changes relative to a baseline period (1981–2010) were used to assess climate impacts. For local basins that discharge directly to the bay, the ensemble means projected increases in Qss of 27% for the mid-century (2040–2069) and 58% for the end-of-century (2070–2099). For the Eel River, a regional sediment source that discharges sediment-laden plumes to the coastal margin, the ensemble means projected increases in Qss of 53% for the mid-century and 99% for the end-of-century. Climate projections of increased precipitation and streamflow produced amplified increases in the regional sediment supply that may partially or wholly mitigate sediment demand caused by the combined effects of subsidence and SLR. This finding has important implications for coastal resiliency. Coastal regions with an increasing sediment supply may be more resilient to SLR. In a broader context, an increasing sediment supply from fluvial sources has global relevance for communities threatened by SLR that are increasingly building resiliency to SLR using sediment-based solutions that include regional sediment management, beneficial reuse strategies, and marsh restoration.

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Human subsistence changes during the late Holocene: resource overexploitation or climate change in the upper Atuel river valley, Argentina

Quaternary International ◽

10.1016/j.quaint.2012.08.1045 ◽

2012 ◽

Vol 279-280 ◽

pp. 349

Author(s):

Gustavo Neme

Keyword(s):

Climate Change ◽

Late Holocene ◽

River Valley ◽

Human Subsistence

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Post-LGM glacial retreat drives aggradation in the interiors of the Kashmir Himalaya

10.31223/x5m91g ◽

2021 ◽

Author(s):

Saptarshi Dey ◽

Naveen Chauhan ◽

Anushka Vashistha ◽

Vikrant Jain

Keyword(s):

Climate Change ◽

Foreland Basin ◽

High Elevation ◽

Sediment Supply ◽

Kashmir Himalaya ◽

Glacial Retreat ◽

Valley Fill ◽

Mean Grain Size ◽

Exposure Ages ◽

Semi Arid

Understanding the response of glaciated catchments to climate change is fundamental for assessing sediment transport from the high-elevation, semi-arid to arid sectors in the Himalaya to the foreland basin. The fluvioglacial sediments stored in the semi-arid Padder valley in the Kashmir Himalaya record valley aggradation during ~19-11 ka. We relate the valley aggradation to increased sediment supply from the deglaciated catchment during the glacial-to-interglacial phase transition. Previously-published bedrock-exposure ages in the upper Chenab valley suggest ~180 km retreat of the valley glacier during ~20-15 ka. Increasing roundness of sand-grains and reducing mean grain-size from the bottom to the top of the valley-fill sequence hint about increasing fluvial transport with time and corroborate with the glacial retreat history. Our result also correlates well with late Pleistocene-early Holocene sediment aggradation observed across most Western Himalayan valleys. It highlights the spatiotemporal synchronicity of sediment transfer from the Himalayas triggered by climate change.

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SedCas_Volcano: Simulating decadal patterns of lahar hazard and sediment transfer following volcanic disturbance in the Belham River Valley, Montserrat

10.5194/egusphere-egu21-5694 ◽

2021 ◽

Author(s):

James Christie ◽

Georgina Bennett ◽

Jacob Hirschberg ◽

Jenni Barclay ◽

Richard Herd

Keyword(s):

Volcanic Activity ◽

Vegetation Cover ◽

Volcanic Eruptions ◽

River Valley ◽

Sediment Supply ◽

Recovery Cycle ◽

Frequency Distributions ◽

Volcanic Disturbance ◽

Multi Phase ◽

Disturbance Recovery

Explosive volcanic eruptions are among the most significant natural disturbances to landscapes on Earth. The widespread and rapid influx of pyroclastic sediment, together with subsequent changes to topography and vegetation cover, drives markedly heightened runoff responses to rainfall and increased downstream water and sediment fluxes; principally by way of hazardous lahars. The nature and probability of lahar occurrence under given rainfall conditions evolves as the landscape responds and subsequently recovers following the disturbance. The relationship between varying sediment supply, rainfall patterns, vegetation cover and lahar activity is complex, and impedes forecasting efforts made in the interest of hazard and land use management. Thus, developing an improved understanding of how these systems evolve in response to volcanic eruptions is of high importance.Here we present SedCas_Volcano[MOU1]&#160;, a conceptual sediment cascade model, designed to simulate the first-order trends, such as magnitude-frequency distributions or seasonal patterns, in lahar activity and sediment transport. We use the Belham River Valley, Montserrat, as a case study. This small (~15km2) catchment has been repeatedly disturbed by five phases of volcanic activity at the Soufri&#232;re Hills Volcano since 1995. The multi-phase nature of this eruption, together with the varying nature and magnitude of disturbances throughout the eruption, has driven a complex disturbance-recovery cycle, which is further compounded by inter-annual climatic variations (e.g. ENSO). Lahars have occurred frequently in response to rainfall in the Belham River Valley, and their occurrence has evolved through the repeated disturbance-recovery cycle. This activity has resulted in significant net valley floor aggradation and widening, consequent burial and destruction of buildings and infrastructure, as well as coastal aggradation of up to ~250m. Within SedCas_Volcano, we account for evolving sediment supply, vegetation cover and rainfall, to simulate the lahar activity and channel change observed in the Belham River Valley since January 2001. Following this, we test the model under different hypothetical eruptive scenarios. [MOU2]&#160;Our goal is to assess the efficacy of such models for reproducing patterns of lahar activity and geomorphic change in river systems that are repeatedly disturbed by volcanic activity.

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Disentangling the relative impacts of climate change and human activities on fluvial sediment supply to the coast by the world’s large rivers: Pearl River Basin, China

Scientific Reports ◽

10.1038/s41598-019-45442-2 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 7

Author(s):

Roshanka Ranasinghe ◽

Chuang Shou Wu ◽

John Conallin ◽

Trang Minh Duong ◽

Edward Jamal Anthony

Keyword(s):

Climate Change ◽

River Basin ◽

Human Activities ◽

Sediment Supply ◽

Large Rivers ◽

Pearl River ◽

Pearl River Basin ◽

Fluvial Sediment ◽

Impacts Of Climate Change

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Fluvial response to rapid climate change during the Devensian (Weichselian) Lateglacial in the River Great Ouse, southern England, UK

Sedimentary Geology ◽

10.1016/j.sedgeo.2007.02.004 ◽

2007 ◽

Vol 202 (1-2) ◽

pp. 193-210 ◽

Cited By ~ 23

Author(s):

C. Gao ◽

S. Boreham ◽

R.C. Preece ◽

P.L. Gibbard ◽

R.M. Briant

Keyword(s):

Climate Change ◽

Southern England ◽

Rapid Climate Change ◽

Fluvial Response

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Are mangroves in Victoria (south-eastern Australia) already responding to climate change?

Marine and Freshwater Research ◽

10.1071/mf17015 ◽

2017 ◽

Vol 68 (12) ◽

pp. 2366 ◽

Cited By ~ 5

Author(s):

Paul I. Boon

Keyword(s):

Climate Change ◽

Sediment Supply ◽

Small Scale ◽

Storm Activity ◽

Plant Vigour ◽

South Eastern ◽

Run Off ◽

Eastern Australia ◽

Wide Range ◽

South Eastern Australia

The distribution and productivity of mangroves is directly affected by a wide range of climatic drivers, including temperature, frost, rainfall, evaporation and storm activity, which, in turn, influence a suite of secondary drivers, including changes in freshwater run-off and sediment supply, groundwater dynamics and inter-species competitiveness. The highest-latitude expression of mangroves globally is at Millers Landing, Victoria (38°45′S), and because the vigour and productivity of mangroves across much of Victoria is thought to be limited by low winter temperatures and the incidence and severity of frosts, it is likely that mangroves will be among the first plant communities to be affected by climate change in coastal south-eastern Australia. An increase in plant vigour is likely, but there are almost no historical data with which to compare current rates of primary production. An extension of mangroves to higher latitudes on the mainland is impossible because of the geomorphology of the land that lies further to the south. Small-scale changes in distribution, including the progressive encroachment of mangroves into coastal saltmarsh, are likely to be among the clearest indications of the response of mangroves to a warming climate. Increased effort into tracking changes in mangrove vigour, productivity and distribution is clearly warranted.

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