Editing Sediment flux to rivers/coasts

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{| class="wikitable" style="float:right; clear:right; margin:0 0 1em 1em; width:320px;"
|+ SIGNAL Earth Structured Data
|-
! Object type
| Damage Signal
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! SIGNAL Earth ID
| DS-00145
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! Observable type
| Sediment flux to rivers/coasts
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! Unit
| t/year (t/year (metric tons per year))
|-
! Temporal structure
| Annual
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! Monitoring backbone
| —
|}
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{{SignalTerm|type=DS|id=DS-00145|label=Sediment flux to rivers/coasts}} Sediment flux to rivers and coasts refers to the annual transport of sediment particles from terrestrial landscapes into river systems and subsequently to coastal environments. This process plays a critical role in shaping river morphology, influencing aquatic habitats, and sustaining coastal landforms. Sediment flux is a key component of the Earth's surface dynamics, linking terrestrial erosion processes with fluvial and marine sedimentary systems.

The magnitude and variability of sediment flux are influenced by natural factors such as climate, geology, vegetation cover, and hydrology, as well as human activities including land use changes, dam construction, and river engineering. Understanding sediment flux is essential for assessing sediment budgets, managing water quality, and predicting changes in coastal erosion and delta formation.

Within the context of global environmental monitoring, sediment flux to rivers and coasts provides insight into the state of land surface processes and their connectivity to aquatic systems. It also informs assessments of anthropogenic impacts on sediment transport pathways and the resulting environmental consequences.

== Geographic / System Context ==
Sediment flux to rivers and coasts occurs globally, spanning diverse geographic and climatic regions. It encompasses sediment mobilization from upland and lowland areas, transport through river networks, and delivery to coastal zones including deltas, estuaries, and continental shelves. The spatial distribution of sediment flux is heterogeneous, reflecting variations in watershed size, topography, land cover, and precipitation patterns.

Major river basins such as the Amazon, Mississippi, Yangtze, and Ganges contribute significant sediment loads to their respective coastal margins. Human interventions, such as damming and land management practices, have altered sediment fluxes in many regions, leading to changes in sediment supply downstream and affecting coastal sediment budgets worldwide.

== Monitoring and Measurement ==
Sediment flux to rivers and coasts is monitored through a combination of field measurements, remote sensing, and modeling approaches. Direct measurements include suspended sediment concentration sampling and bedload transport assessments at gauging stations within river systems. Sediment traps and turbidity sensors provide additional data on sediment transport dynamics.

Remote sensing techniques, such as satellite imagery and aerial photography, enable large-scale observation of sediment plumes and coastal sediment distribution. Hydrological and sediment transport models integrate observational data to estimate sediment fluxes over broad spatial and temporal scales. Scientific institutions and monitoring programs contribute to data collection and analysis, although a consolidated global monitoring backbone for sediment flux is still under development.

Within the SIGNAL system, this phenomenon is treated as a defined environmental signal whose boundaries and measurement conventions are described below.

== Signal Definition ==
The sediment flux to rivers/coasts signal quantifies the annual mass of sediment, expressed in tonnes per year (t/year), transported from terrestrial environments into river systems and delivered to coastal zones. It represents a state condition within the land domain reflecting the net sediment transfer through fluvial pathways to the ocean or inland water bodies.

== Boundary Conditions ==
Boundary inclusions encompass all sediment particles mobilized from land surfaces that enter river channels and are transported downstream to coastal or inland receiving waters within a defined watershed. This includes both suspended sediment and bedload components transported during surface runoff and baseflow conditions.

Boundary exclusions involve sediment sources and sinks outside the terrestrial-to-coastal transport pathway, such as aeolian (wind-driven) sediment transport, sediment resuspension within marine environments, and sediment deposition occurring upstream of the river channel network. Anthropogenic sediment inputs directly discharged into water bodies without passing through natural terrestrial erosion processes are also excluded.

== Aggregation Semantics ==
Geographically, sediment flux data are aggregated at watershed or river basin scales to capture integrated sediment transport dynamics from source areas to coastal outlets. Temporal aggregation is conducted on an annual basis to account for seasonal variability and provide standardized reporting intervals.

Cross-signal aggregation may involve integration with related environmental signals such as freshwater suspended sediment concentration and sediment delivery ratio to assess sediment transport efficiency and impacts on aquatic ecosystems. Aggregation approaches consider spatial heterogeneity and temporal fluctuations to support comprehensive environmental assessments.

== Observational Status ==
Current monitoring of sediment flux to rivers and coasts relies on a combination of localized measurements and model-based estimates, with ongoing efforts to enhance global coverage and data consistency. The observational backbone for this signal is under development, aiming to incorporate standardized methodologies and integrate multi-source datasets.

Future SIGNAL releases may include expanded datasets, improved temporal resolution, and enhanced linkage with complementary environmental signals. Continued research and technological advancements are expected to refine sediment flux quantification and support more detailed assessments of sediment dynamics under changing environmental conditions.

== Related Signals ==
* Coastal erosion extent
* Extreme precipitation intensity
* Freshwater suspended sediment concentration
* Sediment delivery ratio
* Sediment-laden runoff to receiving waters

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== Key Associated People ==
* '''Emily N. Dethier''' [Lead author]
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== Sources ==
* [https://www.science.org/doi/10.1126/science.abn7980 Rapid changes to global river suspended sediment flux by humans — 2022]
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