Editing Sediment Transport Flux

<!-- SIGNAL_EARTH_INFOBOX_START -->
{| class="wikitable" style="float:right; clear:right; margin:0 0 1em 1em; width:320px;"
|+ SIGNAL Earth Structured Data
|-
! Object type
| Damage Signal
|-
! SIGNAL Earth ID
| DS-00173
|-
! Observable type
| Sediment transport flux
|-
! Unit
| t/year (metric tons of sediment transported per year)
|-
! Temporal structure
| Periodic
|-
! Monitoring backbone
| —
|}
<!-- SIGNAL_EARTH_INFOBOX_END -->

{{SignalTerm|type=DS|id=DS-00173|label=Sediment Transport Flux}} refers to the rate at which sediment particles are moved through a given area, typically measured in tonnes per year. This phenomenon plays a critical role in shaping terrestrial and aquatic environments by influencing river morphology, coastal dynamics, and ecosystem health. Understanding sediment transport flux is essential for assessing natural processes such as erosion and deposition, as well as human impacts on sediment cycles.

Sediment transport flux is a key indicator of environmental state within the water domain, reflecting the balance between sediment sources, transport mechanisms, and sinks. Changes in sediment flux can affect water quality, habitat structure, and geomorphological stability. It is relevant for managing water resources, mitigating hazards like sedimentation or erosion, and studying the effects of infrastructure and land use changes.

This signal is observed globally, encompassing riverine, coastal, and marine sediment transport processes. It integrates data from diverse geographic regions and temporal scales, providing a comprehensive view of sediment dynamics under varying natural and anthropogenic influences.

== Geographic / System Context ==
Sediment transport flux occurs across a wide range of geographic settings, including river basins, estuaries, coastal zones, and continental shelves. Globally, river systems transport sediment from upland erosion areas to downstream depositional environments, influencing delta formation and coastal sediment budgets. Coastal regions are particularly sensitive to sediment flux variations, which can alter shoreline stability and marine habitats.

The global scope of sediment transport flux encompasses diverse environmental systems, from mountainous catchments with high sediment yield to lowland floodplains where sediment deposition dominates. Human activities such as dam construction, land use change, and urbanization have modified sediment pathways, often disrupting natural sediment delivery to downstream and coastal ecosystems.

== Monitoring and Measurement ==
Monitoring sediment transport flux involves a combination of field measurements, remote sensing, and modeling techniques. River sediment load is commonly measured using suspended sediment concentration sampling, bedload traps, and turbidity sensors. Sediment flux is calculated by integrating sediment concentration with water discharge over time.

Institutions such as the United States Geological Survey ([https://en.wikipedia.org/wiki/United_States_Geological_Survey USGS]) and international research programs contribute to sediment monitoring networks. Advances in satellite remote sensing allow for broader spatial coverage and temporal resolution, enabling the assessment of sediment plumes, coastal erosion, and sediment deposition patterns. Sediment transport models further support understanding of flux dynamics under varying hydrological and climatic conditions.

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

== Signal Definition ==
Sediment transport flux is defined as the mass of sediment transported through a specified cross-sectional area of a water body per unit time, expressed in tonnes per year (t/year). It represents a state condition within the water domain, quantifying the movement of sediment particles suspended or rolling along the bed, driven by hydrodynamic forces.

== Boundary Conditions ==
Boundary inclusions encompass sediment transported by fluvial, coastal, and marine processes within natural and modified watercourses and adjacent environments. This includes suspended sediments, bedload, and sediment carried in overbank flows.

Boundary exclusions include sediment fluxes unrelated to waterborne transport, such as aeolian (wind-driven) sediment movement, sediment trapped permanently behind dams without downstream transport, and sediment fluxes within closed basins lacking outflow. Anthropogenic sediment inputs from point sources may be included if they contribute to measurable downstream transport.

== Aggregation Semantics ==
Geographic aggregation of sediment transport flux data is conducted at multiple spatial scales, from local river reaches to entire drainage basins and global sediment budgets. Temporal aggregation typically follows periodic intervals such as annual or seasonal flux totals to capture variability and trends.

Cross-signal aggregation involves integrating sediment transport flux with related environmental signals, including coastal erosion extent and freshwater ecosystem condition indices, to provide a holistic understanding of sediment-related environmental changes. Aggregation methods account for spatial heterogeneity and temporal fluctuations to support comprehensive environmental assessments.

== Observational Status ==
Current monitoring of sediment transport flux is supported by a combination of in situ measurements and remote sensing, though global coverage remains uneven due to logistical and technical challenges. Data availability varies regionally, with well-studied river basins providing robust time series, while many areas lack systematic observations.

Future SIGNAL releases aim to incorporate expanded datasets, improved temporal resolution, and enhanced integration with related environmental signals. Advances in sensor technology and modeling are expected to refine sediment flux estimates and support more detailed assessments of sediment dynamics under changing environmental conditions.

== Related Signals ==
* Coastal erosion extent
* Freshwater ecosystem condition index
* Marine construction disturbance from offshore energy infrastructure
* Sediment transport interruption from impoundment infrastructure

<!-- SIGNAL_EARTH_PEOPLE_START -->
== Key Associated People ==
* '''Emily N. Dethier''' [Lead author]
<!-- SIGNAL_EARTH_PEOPLE_END -->

<!-- SIGNAL_EARTH_SOURCES_START -->
== Sources ==
* [https://www.science.org/doi/10.1126/science.abn7980 Rapid changes to global river suspended sediment flux by humans — 2022]
<!-- SIGNAL_EARTH_SOURCES_END -->