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Joshua B. Logan

Publications and source records attributed to Joshua B. Logan.

42 records · Page 3Linked to original sources
USGS2007

Geologic resource evaluation of Pu‘uhonua O Hōnaunau National Historical Park, Hawai‘i. Part II: Benthic habitat mapping

In cooperation with the U.S. National Park Service (NPS), the U.S. Geological Survey (USGS) has mapped the underwater environment in and adjacent to three parks along the Kona coast on the island of Hawai‘i. This report is the second of two produced for the NPS on the geologic resource evaluation of of Pu‘uhonua O Hōnaunau National Historical Park (PUHO) and presents the results of benthic habitat mapping of the offshore waters for PUHO. See Part I (Richmond and others, 2006) for an overview of the regional geology, local volcanics, and a detailed description of coastal landforms in the park. Pu‘uhonua O Hōnaunau National Historical Park boundaries extend only to the mean high tide line and do not officially include the marine environment. However, impacts downslope of any development in the park are of concern to management. The area mapped for this report extends from Hōnaunau Bay, around Pu‘uhonua Point, to Ki‘ilae Bay and the south park boundary and from the shoreline to depths of approximately 40 m (130 ft), where the shelf drops off to a sand-covered bottom. Pu‘uhonua O Hōnaunau National Historical Park lies within the nearly 850-km2 Ki‘ilae watershed, which begins at the crest of Mauna Loa. The Ki‘ilae Watercourse runs through the southern area of the park and empties into Ki‘ilae Bay, but only during periods of extreme rainfall. The waters of Keone‘ele Cove, the ancient royal canoe landing at PUHO, while not formally under NPS jurisdiction, are managed by the park under an agreement with the State of Hawaii. This small embayment is a known haven for sea turtles, which are often found sunning themselves on the near- shore volcanic platform. Impacts to this area include frequent visits by scuba divers and snorkelers to Hōnaunau Bay and a small boat ramp located just to the north of Keone‘ele Cove.

Hawai'i↗
USGS2006

Coastal circulation and sediment dynamics in Hanalei Bay, Kauai, Part I, Measurements of waves, currents, temperature, salinity and turbidity; June–August, 2005

High-resolution measurements of waves, currents, water levels, temperature, salinity and turbidity were made in Hanalei Bay, northern Kauai, Hawaii, during the summer of 2005 to better understand coastal circulation and sediment dynamics in coral reef habitats. A series of bottom-mounted instrument packages were deployed in water depths of 10 m or less to collect long-term, high-resolution measurements of waves, currents, water levels, temperature, salinity and turbidity. These data were supplemented with a series of vertical instrument casts to characterize the vertical and spatial variability in water column properties within the bay. The purpose of these measurements was to collect hydrographic data to learn how waves, currents and water column properties vary spatially and temporally in an embayment that hosts a nearshore coral reef ecosystem adjacent to a major river drainage. These measurements support the ongoing process studies being conducted as part of the U.S. Geological Survey (USGS) Coastal and Marine Geology Program's Coral Reef Project; the ultimate goal is to better understand the transport mechanisms of sediment, larvae, pollutants and other particles in coral reef settings. This report, the first part in a series, describes data acquisition, processing and analysis.

Hawaii↗
USGS2006

Coastal circulation and sediment dynamics in Hanalei Bay, Kaua'i, Hawaii: Part II: Tracking recent fluvial sedimentation: Isotope stratigraphy obtained in Summer 2005

Delivery and dispersal of fluvial sediment in Hanalei Bay, Kaua’i, Hawaii, have important implications for the health of local coral reefs. The reef community in Hanalei Bay represents a relatively healthy ecosystem. However, the reefs are periodically stressed by storm waves, and increases in sediment and dissolved substances from the Hanalei River have the potential to cause additional stress. Increased turbidity and sedimentation on corals during Hanalei River floods that occur in seasons of low wave energy, when sediment would not be readily remobilized and advected out of the bay, could affect the health and sustainability of coral reefs and the many associated species. Measurements of short-lived isotopes 7 Be and 137 Cs in sediment cores have been used to trace the thickness and distribution of terrestrial sediment in Hanalei Bay, in order to assess spatial and temporal patterns of sediment deposition and remobilization relative to coral-reef locations. A third isotope, 210 Pb, derived primarily from seawater, provides additional information about recent sedimentary history. Isotope profiles and observations of sedimentary facies from cores collected at multiple locations in June 2005, and again in August 2005, indicate the presence of recent fluvial sediment and organic debris in the east part of the bay near the mouth of the Hanalei River. Away from the immediate vicinity of the river mouth, sediment in the uppermost 1 m below the sea floor had not retained a significant quantity of fluvial sediment within the eight months prior to either sampling effort. During the study interval in summer 2005 the Hanalei River had no major floods and there was relatively little sediment input to the bay. Sediment away from the river mouth was dominated by carbonate sand, although some terrestrial sediment was present in sub-sea-floor horizons. Sedimentary facies and isotope inventories throughout the bay showed substantial spatial heterogeneity. Sediment cores will be collected again at the same sites discussed here during early and late summer 2006. If possible, additional sites will be sampled in the Black Hole depocenter near the river mouth. Major floods in winter and spring 2006 are expected to leave a significant new sediment signal in the bay that should be detected in summer 2006.

Hawaii↗
USGS2004

Coastal circulation and sediment dynamics along West Maui, Hawaii: Part III: Flow and particulate dynamics during the 2003 summer coral spawning season

High-resolution measurements of currents, temperature, salinity and turbidity were made over the course of three months off West Maui in the summer and early fall of 2003 to better understand coastal dynamics in coral reef habitats. Measurements were made through the emplacement of a series of bottom-mounted instruments in water depths less than 11 m. The studies were conducted in support of the U.S. Geological Survey (USGS) Coastal and Marine Geology Program's Coral Reef Project. The purpose of these measurements was to collect hydrographic data to better constrain the variability in currents and water column properties such as water temperature, salinity and turbidity in the vicinity of nearshore coral reef systems over the course of a summer and early fall when coral larvae spawn. These measurements support the ongoing process studies being conducted under the Coral Reef Project; the ultimate goal is to better understand the transport mechanisms of sediment, larvae, pollutants and other particles in coral reef settings. This report, the third in a series of three, describes data acquisition, processing and analysis.

Hawaii↗