Reef Hydrodynamics and Sediment Processes Active
As part of the USGS Coral Reef Project, the overall objective of this research effort is to better understand how circulation and sediment processes impact coral reefs and their adjacent coastlines.
The Problem
Over the past decade, we have primarily focused on fine-grained terrestrial sediment dynamics on reefs, due to its role as the greatest stressor to high-island fringing reefs throughout the U.S. and U.S.-Affiliated Pacific Islands, such as Hawaii, Guam, American Samoa, and large Office of Insular Affairs islands. However, recently we have expanded our focus to include carbonate sediment, as approximately 80-90% of coral reefs are constructed of lithified carbonate sediment (carbonate sand and rubble adhered together by calcareous algae, not intact coral growth). Because this carbonate sediment is a critical component of beach sediment supply, it represents an important resource for recreation and coastal storm protection. Although a key factor in the vertical growth of reefs and their ability to keep up with rising sea levels, carbonate reef sediment dynamics are poorly understood and this knowledge gap was recently determined to be a critical area of research for investigating climate-change impacts to coral reef-lined coasts.
Our Approach
The overall objective of this research is to better understand how hydrodynamics and sediment processes influence the development of coral reefs and their adjacent shorelines. Specifically, we are:
- Evaluating the role of coral-reef morphology on waves and wave-driven water levels over coral reefs and their resulting influence on coastal flooding.
- Elucidating the patterns of flow over coral reefs that result from different forcing mechanisms such as waves, currents, surface tides, internal tides, and subtidal motions.
- Determining the sources, pathways, and retention times of sediment, nutrients, and contaminants over complex coral reef morphologies.
- Identifying the circulation pathways that link separate reefs through larval or pollutant transport, and determine the spatial and temporal scales at which these pathways occur.
- Evaluating how these processes and linkages will be affected by projected changes in climate such as sea-level rise and changes in the frequency and intensity of storms.
The overall objective of this research effort is to better understand how circulation and sediment processes impact coral reefs and their adjacent coastlines.
Caption for large photo at top of page: Photograph of large (6-meter-/20-foot-high) waves resuspending terrestrial flood sediment on the coral reefs off Puʻukoholā Heiau National Historic Site and Kawaihae Harbor, Hawaiʻi.
Learn more about our related studies.
Below are data or web applications associated with this project.
Below are publications associated with this project.
Assessing morphologic controls on atoll island alongshore sediment transport gradients due to future sea-level rise
Spatial and temporal variability in ripple formation and migration across a coral reef flat and lagoon
Geochemical sourcing of runoff from a young volcanic watershed to an impacted coral reef in Pelekane Bay, Hawaii
Meteorologic, oceanographic, and geomorphic controls on circulation and residence time in a coral reef-lined embayment: Faga’alu Bay, American Samoa
Spatial variability of sediment transport processes over intratidal and subtidal timescales within a fringing coral reef system
Mechanisms of wave‐driven water level variability on reef‐fringed coastlines
Projected atoll shoreline and run-up changes in response to sea-level rise and varying large wave conditions at Wake and Midway Atolls, Northwestern Hawaiian Islands
The use of passive membrane samplers to assess organic contaminant inputs at five coastal sites in west Maui, Hawaii
Coastal circulation and water-column properties in the National Park of American Samoa, February–July 2015
Sources and dispersal of land-based runoff from small Hawaiian drainages to a coral reef: Insights from geochemical signatures
Sediment transport in the presence of large reef bottom roughness
As part of the USGS Coral Reef Project, the overall objective of this research effort is to better understand how circulation and sediment processes impact coral reefs and their adjacent coastlines.
The Problem
Over the past decade, we have primarily focused on fine-grained terrestrial sediment dynamics on reefs, due to its role as the greatest stressor to high-island fringing reefs throughout the U.S. and U.S.-Affiliated Pacific Islands, such as Hawaii, Guam, American Samoa, and large Office of Insular Affairs islands. However, recently we have expanded our focus to include carbonate sediment, as approximately 80-90% of coral reefs are constructed of lithified carbonate sediment (carbonate sand and rubble adhered together by calcareous algae, not intact coral growth). Because this carbonate sediment is a critical component of beach sediment supply, it represents an important resource for recreation and coastal storm protection. Although a key factor in the vertical growth of reefs and their ability to keep up with rising sea levels, carbonate reef sediment dynamics are poorly understood and this knowledge gap was recently determined to be a critical area of research for investigating climate-change impacts to coral reef-lined coasts.
Our Approach
The overall objective of this research is to better understand how hydrodynamics and sediment processes influence the development of coral reefs and their adjacent shorelines. Specifically, we are:
- Evaluating the role of coral-reef morphology on waves and wave-driven water levels over coral reefs and their resulting influence on coastal flooding.
- Elucidating the patterns of flow over coral reefs that result from different forcing mechanisms such as waves, currents, surface tides, internal tides, and subtidal motions.
- Determining the sources, pathways, and retention times of sediment, nutrients, and contaminants over complex coral reef morphologies.
- Identifying the circulation pathways that link separate reefs through larval or pollutant transport, and determine the spatial and temporal scales at which these pathways occur.
- Evaluating how these processes and linkages will be affected by projected changes in climate such as sea-level rise and changes in the frequency and intensity of storms.
The overall objective of this research effort is to better understand how circulation and sediment processes impact coral reefs and their adjacent coastlines.
Caption for large photo at top of page: Photograph of large (6-meter-/20-foot-high) waves resuspending terrestrial flood sediment on the coral reefs off Puʻukoholā Heiau National Historic Site and Kawaihae Harbor, Hawaiʻi.
Learn more about our related studies.
Below are data or web applications associated with this project.
Below are publications associated with this project.