CRAMP Study Sites
Geographic Name: Island of Kaua‘i
22° 05‘ N, 159° 30‘ W.
located at the northern end of the Hawaiian Island Chain, 113 km (70 mi) north-west of O‘ahu.
NOAA Chart of the island of Kaua‘i.
Physical Features (Physiography) - General Bathymetry, Topography:
Kaua‘i is the northernmost and geologically the oldest and most complex of the main Hawaiian Islands. It is roughly circular in shape and was formed by a single shield volcano. Kaua‘i is the fourth largest of the Main Hawaiian Islands. Kaua‘i has a mean diameter of 26 miles and an area of 555 square miles (143,710 ha). Geology and ground-water resources are described by MacDonald et al. (1960).
The highest peak, Waialeale reaches an elevation of 1540 m (5,052 ft), followed by Kawaikini, at 1600 m (4160 ft). Mountainous terrain occupies the north, west and central part of the island. The gentle east and south slopes are cut by shallow gulches. A narrow, gently sloping coastal plain skirts the island, but is interrupted on the northwest side by a 16 mile stretch of precipitous cliffs (Na Pali) which rise from the water‘s edge, and on the southeast by a the Hoary Head Mountains which rise to elevations of about 7,480 m (2,280 ft.) above sea level. Adjacent to the coastal plain are the longest stretches of excellent beach to be found in the state. Some of these beaches (Kapa‘a, Hanapēpē and Kekaha) have undergone severe erosion in recent years.
The major streams of Kaua‘i have their headwaters in the large central caldera of the volcano. The low slopes, deep soil, high rainfall and tall vegetation enhance stream permanence on Kaua‘i. On the east side of the island permanent streams are fed by springs stemming from the dike complex within the volcano. Kaua‘i has eleven distinctive bays resulting from the drowning of river valleys and 15 streams that feed into significant estuaries (Grace, 1974).
Reef Structure, Habitat Classification:
The tidal shoreline of the island is approximately 189 km (113 miles) long (State of Hawai‘i Department of Planning and Economic Development, 1965). Eleven miles of shoreline exist as vertical sea cliffs higher than 300 m (1,000 ft). These areas of shoreline are virtually inaccessible, with an additional 39 miles that are only marginally inaccessible, leaving about 63 miles of shoreline that can be reached from the land. In many areas, the reef flats are very wide and in some places extend more than 1 km (0.6 mi) from shore. There is significant coverage by reef corals on all sides of the island offshore to depths of 60 feet. However, carbonate reef structure is not actively accreting. In general, carbonates exist Holocene veneers overlying basalt (Grigg, 1983). Reefs along the Kaua‘i coast are dominated by the corals Porites lobata and Pocillopora meandrina, with other common species that include Montipora patula, Montipora flabellata, Leptastrea purpurea and Montipora verrucosa. Most areas show higher fish abundance and diversity than O‘ahu, Maui and Hawai‘i. Fishing pressure is relatively low due to a smaller human population. Also, Kaua‘i has excellent and diverse fish habitats.
There is an ancient drowned "barrier reef" structure exists off Polihale Beach on western shore at 20 m depth. Locally, this structure is known as the "Mana Crack". In addition, numerous drowned sea level terraces exist at 20-60m around island
Due to its northerly location, Kaua‘i falls under the influence of frequent low pressure systems and is the wettest island in the Hawaiian Archipelago. The rainfall stimulates the growth of luxurious vegetation, which gives Kaua‘i its name of "The Garden Island". Mount Waialeale in the center of the island has recorded one of the world‘s highest mean annual rainfalls (over 449 inches per year of 1140 cm/yr.). Rainfall diminishes towards the coast to a minimum of about 20 inches per year (50 cm/yr) on the leeward coast. The prevailing NE Trade Winds divide on the east side of Kaua‘i, with one part flowing along the N coast and one part the S coast. These unite again some distance W of the island. On the west side, between Mana Point and Mākaha Point, calm or light variable winds prevail. Along the N and S shores the early morning trade wind is usually light but increases after 0900 and again decreases in strength after about 1600. Occasionally kona winds, starting in the SE, displace the normal trades. This condition occurs more often during the winter.
The circular shape of Kaua‘i and lack of any nearby islands results in a situation of extremely high wave energy on all shorelines. Hurricane waves caused considerable damage to the south shore reefs of Kaua‘i in 1982 and 1992. Winter swell from the north, summer swell from the south and persistent trade wind swell strike Kaua‘i with full force and refract around its circular shape. The oceanic currents in the vicinity of Kaua‘i generally follow the prevailing wind patterns.
Adjacent Land Tenure, Land Use:
Over 50% of the land belongs to the private sector, 43% to the state of Hawai‘i and the remainder to the federal government.
Human Use Patterns:
Most of the agricultural commercial and residential areas on the island are concentrated along the coastal plain. The rugged central portion of the island is largely timbered or conservation land. Until recently, the growing and processing of sugar cane was the major agricultural activity, but sugar has been phased out and is being replaced with diversified agriculture. Tourism has been a major economic activity, particularly along the south and east shores. Hurricane Iwa (Nov. 1982) and Hurricane Iniki (Sept. 1992) caused extensive damage to the island. Damage to buildings, crops, reefs and the consequent lack of visitors in the years following both hurricanes resulted in major economic impact.
Economic Value and Social Benefits:
The economy of the Island of Kaua‘i is heavily dependent on tourism. Beautiful beaches and healthy reefs are very important components of the entire visitor package. Most visitors spend a part of their time swimming, skin diving, SCUBA diving, touring the coastline by boat or other marine-related activities.
Marine Protected Areas on Kaua‘i:
No Marine Life Conservation Districts have been established on the reefs of Kaua‘i. The few areas with special rules governing human activity consist only of areas being managed in an attempt to sustain recreational fisheries. Two fisheries management areas have been established in coastal waters, with restrictions that mainly apply to the types of fishing gear that can be legally used:
1. Waimea Bay and Waimea recreational Pier on the south coast and
2. Hanamā‘ulu Bay and Ahukini Recreational Pier on the eastern coast.
Authority for managing the marine resources within three miles (4.8 km) of the high tide mark lies with the Division of Aquatic Resources, Department of Land and Natural Resources. All laws pertaining to the management of state marine resources apply (see pamphlet "Hawai‘i Fishing regulations, September 1999", 51 pp. available from Division of Aquatic Resources, Department of Land and Natural Resources, Kalanimoku Building, 1151 Punchbowl St., Rm. 330, Honolulu, Hawai‘i).
Although marine protected areas are lacking, other aquatic areas on Kaua‘i are under various degrees of protection. For example, several wildlife refuges such as the wetlands along lower reaches of the Hulē‘ia River, Hanalei valley and Kīlauea Point provide protected habitat for species of water birds or seabirds. In 1998, Hanalei River on Kaua‘i became one of only fourteen designated American Heritage Rivers. Hanalei River drains onto the reefs of Hanalei Bay, which is one of the CRAMP monitoring locations.
The major concern on Kaua‘i is overuse in highly localized areas. Much of Kaua‘i‘s coastline is not accessible from shore. Further, many reef areas are subject to extreme wave action during much of the year, further restricting reef accessibility to the public. While restricted access has prevented human impact along many stretches of reef, it has resulted in very high levels of human recreational activity on those highly localized reef areas that are accessible. On the Na Pali coastline, shoreline access is non-existent and only a few shoreline areas can be accessed from the sea (Miloli‘i, Nu‘alolo Kai). These have become destination points for boating recreational activity (commercial and private). The increase in the numbers of people arriving at these sites have generated a great deal of concern. swimming, surfing snorkeling and SCUBA diving. Over fishing is a concern, but the relatively small human population has not impacted the reef fisheries to the extent as on neighboring O‘ahu.
Recovery of the reefs from Hurricane Iwa in 1982 and Hurricane Iniki in 1992 took between 5-10 years to re-establish moderate coral cover along much of the south coast that was wave damaged. Wreckage swept from land (including buildings, vehicles, household contents such as refrigerators and stoves, etc.) were removed within the first 1-2 years following the hurricanes. Traces of wreckage can still be found (parts of aluminum door and window frames, concrete blocks, etc.), but the cleanup effort was quite thorough.
Sedimentation due to poor land use practices is always a concern on an island that receives such heavy rainfall. Proposed urban development at many points along the coastline has generated resistance from environmentalists and managers in areas where excessive sediment could be generated during construction.
Noteworthy Flora and Fauna:
A number of fish species that are rare on shallow reefs of the Main Hawaiian Islands can be found on Kaua‘i. A number of these species are commonly found in the Northwestern Hawaiian Islands (NWHI) where it is thought that cooler ocean temperatures, geographical isolation, diversity of habitats, and proximity to major ocean currents provide the necessary ecological requirements of these species. The proximity of Kaua‘i to the NWHI and its northern location favor the occurrence of these species. The bandit angelfish (Desmoholocanthus arcuatus) is relatively common on shallow reefs off Kaua‘i. On the other high islands this fish is only encountered at depths greater than 100 feet. The Knifejaw (Oplegnathidae), is rare in the main islands but two species (Oplegnathus fasciatus and O. punctatus) are occasionally encountered around Kaua‘i. The whiskered armorhead (Evistias acutirostris) also occurs off Kaua‘i. This is a popular food fish in southern Japan and has an antitropical distribution (Hawai‘i, Japan, Lord Howe Island, Kermadec Islands, and northern New Zealand).
The reef coral genus Acropora is one of the dominant reef-building corals in the Indo-Pacific region, but is nearly absent in the main Hawaiian Islands. Several colonies of the table coral (Acropora cytherea), some up to several meters in diameter, have been observed on the submerged Mana barrier reef and a live Acropora colony was collected at a depth of 13 m off Po‘ipū Beach in 1975. These colonies may represent waifs from the NWHI or Johnston Island (1,200 km SW). Records of fossil Acropora throughout Hawai‘i provides evidence that Hawaiian reefs were partially defaunated during the Pleistocene and that distributional discontinuities among the faunas of many Pacific Island coral reefs are due to the net product of local extinction and recolonization (Grigg 1981).
The endangered Hawaiian Monk Seal appears to be increasing in numbers around Kaua‘i. These animals haul out on beaches without fear of humans. Local, State and Federal agencies apparently have succeeded in educating the public on these animals, which seem to be successfully co-existing with humans on Kaua‘i.
Don Heacock, DAR Biologist on Kaua‘i, is involved with protecting endangered Hawaiian Monk Seals in addition to managing reef resources. The seal in the background has hauled out to rest on a public beach. Warning barriers and signs have been erected to avoid disturbance by humans. Photo by Paul L. Jokiel. (Click image for larger view.)
The Historic Preservation Division of the Department of Land and Natural Resources lists over 35,000 properties for the Island of Kaua‘i, with over 855 of these sites being archaeological features. The majority of sites are located in close proximity to the reefs, demonstrating the close relationship of native Hawaiians to the sea.
Scientific Importance and Research Potential:
Compared to the islands of O‘ahu, Maui and Hawai‘i there has been relatively little research conducted on the reefs of Kaua‘i. Historically, this is due to a lack of research institutions on the island. Consequently many research opportunities exist here with abundant and diverse reef resources that in many cases are not severely impacted by human activity.
Last Update: 04/21/2008
By: Lea Hollingsworth
Hawai‘i Coral Reef Assessment & Monitoring Program
Hawai‘i Institute of Marine Biology
P.O. Box 1346
Kāne‘ohe, HI 96744