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Dispersion and hydrology studies provide a better understanding of sediment transport and landscape changes
Volcanic areas are very sensitive to erosion
Volcanic areas are very sensitive to erosion and dispersal of material which changes the landscape rapidly. This requires intensive monitoring to document the type and size of sediment, identify areas where sediment is eroded and deposited, and determine the rate and volume of sediment transport. These sediment data are integrated into computer models to design projects that reduce the impact of sediment accumulation.
Monitoring surveys are conducted in different ways:
Scientists make repeated field measurements over many years. These measurements are made with instruments that measure distance and angle to a reflector, or with GPS equipment using satellite positioning. Scientists compare the cross-sectional profiles obtained over time to assess erosion and deposition in the channel.
Digital Elevation Models (DEMs), which produce highly accurate maps of the land surface, can be created using digital photographs or lidar technology. These models created at different times can be compared to accurately define areas of erosion and deposition. The remotely collected data allows for detailed analysis of basin-wide changes and a deeper understanding of water and geological evolution.
Sediment-laden White River 11 km downstream of the OR35 bridge. Heavy rains resulted in high-sediment loads within this river, which drains Mount Hood, Oregon.
Tracking the amount of sediment and the flow rate of rivers helps mitigate flooding hazards
Instruments installed at stations measure the water level, or stage, of rivers every 15 minutes, and self-pumping samplers frequently take water samples for laboratory analysis. By combining a continuous record of a river’s stage with frequent measurements of water flow and suspended sediment concentration, scientists calculate the total flow of water and suspended sediment to produce daily, monthly and annual totals. Technologies using light transmission (to measure turbidity), sound (hydroacoustic) and imagery (from satellites or digital cameras) allow for greater accuracy and efficiency in documenting sediment loads.
Suspended sediment sample collection from the North Fork Toutle River above the Sediment Retention Structure, downstream from Mount St. Helens.
Annual surveys of water channels in the crater of Mount St. Helens track rates of erosion, aggradation.
Since 2021 VOLCANO ACTIVE FOUNDATION has been committed to the UN Global Compact corporate responsibility initiative and its principles in the areas of human rights, labour, the environment and anti-corruption.
