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Coral Reef Project: Kauaʻi Active

By Pacific Coastal and Marine Science Center August 26, 2021

As part of the USGS Coral Reef Project, the USGS is working on the island of Kauaʻi to identify circulation patterns and a sediment budget for Hanalei Bay to help determine any effects to the coastal marine ecosystem.

Coral Reef Project

Overview

Aerial view of an island with clouds floating above it, with distinctive land features like mountains and agriculture.
Sources/Usage: Public Domain. Visit Media to see details.
This image was acquired on December 26, 2000, by the Enhanced Thematic Mapper plus instrument aboard NASA’s Landsat 7 satellite.

Geologically the oldest of the main eight Hawaiian Islands, the northernmost island of Kauaʻi has a total area of 142 sq km (552 sq mi). This island receives the most rainfall of the main eight Hawaiian Islands, thus giving its nickname of the Garden Isle. Kauaʻi is surrounded on all sides by a fringing reef, with a reef flat sometimes as wide as 1 km (0.6 mi). The reef is under the influence of high wave energy due to the island's geographic position.

 

Motivation

In June 2005 the USGS began a partnership with the Hanalei Watershed Hui. In 1998 the Hanalei River was designated as an American Heritage River in order to foster cooperative, community-based efforts for the preservation of the surrounding environment. The Hanalei River Valley is home to numerous taro farms and water quality and useage for irrigation are of concern. In an effort to halt flooding, levees were built along portions of the river, thus leading to increased discharge into Hanalei Bay during storm events. We are working on identifying circulation patterns and a sediment budget for Hanalei Bay to help determine any effects to the coastal marine ecosystem including coral reefs. 

Underwater, a man wearing a snorkel, fins, and mask swims down to a coral reef with an instrument tied to a tether.
Sources/Usage: Public Domain.
Research geologist Curt Storlazzi free-dives in order to set an instrument on the reef off Kauaʻi, Hawaiʻi in March of 2015.

Other partners working in the Hanalei watershed area include the University of Hawaiʻi, the State of Hawaiʻi (Department of Health, Department of Land and Natural Resources), and Federal organizations (U.S. Department of Agriculture/Natural Resources Conservation Service, Environmental Protection Agency, National Oceanic and Atmospheric Agency). Their sum total have contributed markedly to our understanding of processes in the watershed.

The Hawaiian island of Kauaʻi is just one of the USGS Coral Reef Project's study locations.

Coral Reef Project

Coral head that looks like lettuce sits on sandy bottom in clear blue water and is surrounded by brightly colored fish.
Coral Reef Project

Project Study Locations

A geologic tour of the Hawaiian Islands: Maui...
Study Locations

Coral Reef Facts

Simple illustration of coral anatomy showing tentacles, mouth, polyps, corallium, nenatocysts, zooxanthellae.
Coral Reef Facts
link
Underwater photograph of a shallow, partially sandy reef environment with a 3-legged metal frame holding instruments.

Reef Hydrodynamics and Sediment Processes

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.
By
Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center
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Reef Hydrodynamics and Sediment Processes

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.
Learn More
link
Underwater photo of corals taken from a video feed, where the camera displays text on the image like date and location.

Reef Resource Assessments - Planning for the Future

We are mapping and assessing all of the important geologic and oceanographic factors to identify those coral reefs most at risk and those reefs that are potentially the most resilient and the most likely to recover from natural and human-driven impacts.
By
Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center
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Reef Resource Assessments - Planning for the Future

We are mapping and assessing all of the important geologic and oceanographic factors to identify those coral reefs most at risk and those reefs that are potentially the most resilient and the most likely to recover from natural and human-driven impacts.
Learn More
link
Underwater photo of a shallow coral environment.

Role of Reefs in Coastal Protection

We are combining ocean, engineering, ecologic, social, and economic modeling to provide a high-resolution, rigorous, spatially-explicit valuation of the coastal flood protection benefits provided by coral reefs and the cost effectiveness of reef restoration for enhancing those benefits.
By
Natural Hazards Mission Area, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center
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Role of Reefs in Coastal Protection

We are combining ocean, engineering, ecologic, social, and economic modeling to provide a high-resolution, rigorous, spatially-explicit valuation of the coastal flood protection benefits provided by coral reefs and the cost effectiveness of reef restoration for enhancing those benefits.
Learn More
link
Cartoon showing the cross-section of a hill near an ocean and the movement of groundwater underneath.

Hydrogeology and Reef Health

As part of the USGS Coral Reef Project, we are conducting geophysical and geochemical research to address questions about coastal groundwater-to-reef flow and coral reef health, with the goal of informing management decisions related to planning and implementing activities in priority watershed-coral reef systems.
By
Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center
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Hydrogeology and Reef Health

As part of the USGS Coral Reef Project, we are conducting geophysical and geochemical research to address questions about coastal groundwater-to-reef flow and coral reef health, with the goal of informing management decisions related to planning and implementing activities in priority watershed-coral reef systems.
Learn More
link
Computed tomography scan and photograph of a coral core section, side-by-side.

Climate Change and Land-use Histories

As part of the USGS Coral Reef Project, we are developing new and unique oceanographic and environmental archives from coral skeleton records to better understand the compounding effects of land-use and environmental change on coral reef health.
By
Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center, 3-D CT Core Imaging Laboratory, Core Preparation and Analysis Laboratory and Sample Repositories, Multi-Sensor Core Logger Laboratory
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Climate Change and Land-use Histories

As part of the USGS Coral Reef Project, we are developing new and unique oceanographic and environmental archives from coral skeleton records to better understand the compounding effects of land-use and environmental change on coral reef health.
Learn More

Below are data releases associated with this project.

Dynamically downscaled future wave projections from SWAN model results for the main Hawaiian Islands

Projected wave climate trends from WAVEWATCH3 model output were used as input for nearshore wave models (for example, SWAN) for the main Hawaiian Islands to derive data and statistical measures (mean and top 5 percent values) of wave height, wave period, and wave direction for the recent past (1996-2005) and future projections (2026-2045 and 2085-2100). Three-hourly global climate model (GCM) wind
By
Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

Projected flooding extents and depths based on 10-, 50-, 100-, and 500-year wave-energy return periods, with and without coral reefs, for the States of Hawaii and Florida, the Territories of Guam, American Samoa, Puerto Rico, and the U.S. Virgin Islands,

This data release provides flooding extent polygons (flood masks) and depth values (flood points) based on wave-driven total water levels for 22 locations within the States of Hawaii and Florida, the Territories of Guam, American Samoa, Puerto Rico, and the U.S. Virgin Islands, and the Commonwealth of the Northern Mariana Islands. For each of the 22 locations there are eight associated flood mask
By
Natural Hazards Mission Area, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

Below are multimedia items associated with this project.

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Below are publications associated with this project.

Filter Total Items: 20

Rebounds, regresses, and recovery: A 15-year study of the coral reef community at Pila‘a, Kaua‘i after decades of natural and anthropogenic stress events

Pila‘a reef on the north shore of Kaua‘i, Hawai‘i was subjected to a major flood event in 2001 that deposited extensive sediment on the reef flat, resulting in high coral mortality. To document potential recovery, this study replicated benthic and sediment surveys conducted immediately following the event and 15 years later. Coral cores were analyzed to determine coral growth rates and density. Ou
By
Natural Hazards Mission Area, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center, 3-D CT Core Imaging Laboratory, Core Preparation and Analysis Laboratory and Sample Repositories

The value of US coral reefs for flood risk reduction

Habitats, such as coral reefs, can mitigate increasing flood damages through coastal protection services. We provide a fine-scale, national valuation of the flood risk reduction benefits of coral habitats to people, property, economies and infrastructure. Across 3,100 km of US coastline, the top-most 1 m of coral reefs prevents the 100-yr flood from growing by 23% (113 km2), avoiding flooding to 5
By
Natural Hazards Mission Area, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

Physicochemical controls on zones of higher coral stress where Black Band Disease occurs at Mākua Reef, Kauaʻi, Hawaiʻi

Pervasive and sustained coral diseases contribute to the systemic degradation of reef ecosystems, however, to date an understanding of the physicochemical controls on a coral disease event is still largely lacking. Water circulation and residence times and submarine groundwater discharge all determine the degree to which reef organisms are exposed to the variable chemistry of overlying waters; und
By
Natural Hazards Mission Area, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

Rigorously valuing the role of U.S. coral reefs in coastal hazard risk reduction

The degradation of coastal habitats, particularly coral reefs, raises risks by increasing the exposure of coastal communities to flooding hazards. The protective services of these natural defenses are not assessed in the same rigorous economic terms as artificial defenses, such as seawalls, and therefore often are not considered in decision making. Here we combine engineering, ecologic, geospatial
By
Natural Hazards Mission Area, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

Stream sediment geochemistry of four small drainages on the north shore of Kauai west of Hanalei

Geochemical compositions of fine-grained stream sediment from four drainages on the north shore of the island of Kauai, Hawaii, west of Hanalei and two back-beach sites were explored to increase understanding about land-based runoff and ecological risk from runoff to nearshore coral communities. Stream and beach sediment were collected between July 30 and August 2, 2016, and major, minor, and trac
By
Natural Hazards Mission Area, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

The effectiveness of coral reefs for coastal hazard risk reduction and adaptation

The world’s coastal zones are experiencing rapid development and an increase in storms and flooding. These hazards put coastal communities at heightened risk, which may increase with habitat loss. Here we analyse globally the role and cost effectiveness of coral reefs in risk reduction. Meta-analyses reveal that coral reefs provide substantial protection against natural hazards by reducing wave en
By
Pacific Coastal and Marine Science Center

From ridge to reef—linking erosion and changing watersheds to impacts on the coral reef ecosystems of Hawai‘i and the Pacific Ocean

Coral reef ecosystems are threatened by unprecedented watershed changes in the United States and worldwide. These ecosystems sustain fishing and tourism industries essential to the economic survival of many communities. Sediment, nutrients, and pollutants from watersheds are increasingly transported to coastal waters, where these contaminants damage corals. Although pollution from watersheds is on
By
Ecosystems Mission Area, Pacific Island Ecosystems Research Center, Pacific Coastal and Marine Science Center

Hydrodynamics of a bathymetrically complex fringing coral reef embayment: Wave climate, in situ observations, and wave prediction

This paper examines the relationship between offshore wave climate and nearshore waves and currents at Hanalei Bay, Hawaii, an exposed bay fringed with coral reefs. Analysis of both offshore in situ data and numerical hindcasts identify the predominance of two wave conditions: a mode associated with local trade winds and an episodic pattern associated with distant source long-period swells. Analys
By
Pacific Coastal and Marine Science Center

The use (and misuse) of sediment traps in coral reef environments: Theory, observations, and suggested protocols

Sediment traps are commonly used as standard tools for monitoring “sedimentation” in coral reef environments. In much of the literature where sediment traps were used to measure the effects of “sedimentation” on corals, it is clear from deployment descriptions and interpretations of the resulting data that information derived from sediment traps has frequently been misinterpreted or misapplied. De
By
Woods Hole Coastal and Marine Science Center, Pacific Coastal and Marine Science Center

Science-Based Strategies for Sustaining Coral Ecosystems

Coral ecosystems and their natural capital are at risk. Greenhouse gas emissions, overfishing, and harmful land-use practices are damaging our coral reefs. Overwhelming scientific evidence indicates that the threats are serious, and if they are left unchecked, the ecological and social consequences will be significant and widespread. Although the primary stressors to coral ecosystems are known, sc
By
Natural Hazards Mission Area, Coastal and Marine Hazards and Resources Program

Sedimentation processes in a coral reef embayment: Hanalei Bay, Kauai

Oceanographic measurements and sediment samples were collected during the summer of 2006 as part of a multi-year study of coastal circulation and the fate of terrigenous sediment on coral reefs in Hanalei Bay, Kauai. The goal of this study was to better understand sediment dynamics in a coral reef-lined embayment where winds, ocean surface waves, and river floods are important processes. During a

Sources of land-derived runoff to a coral reef-fringed embayment identified using geochemical tracers in nearshore sediment traps

Geochemical tracers, including Ba, Co, Th, 7Be, 137Cs and 210Pb, and magnetic properties were used to characterize terrestrial runoff collected in nearshore time-series sediment traps in Hanalei Bay, Kauai, during flood and dry conditions in summer 2006, and to fingerprint possible runoff sources in the lower watershed. In combination, the tracers indicate that runoff during a flood in August coul

Below are partners associated with this project.

Hanalei Watershed Hui

Hawai'i Department of Land and Natural Resources

Hawai‘i Department of Health

National Oceanic and Atmospheric Administration (NOAA)

University of Hawai'i

USDA Natural Resources Conservation Service (NRCS)