C O A S T A L E N G I N E E R I N G

Benthic Boundary Layer Geochemistry and Physics at the Kilo Nalu Observatory
This project aims to significantly advance our ability to measure the transport of solutes into and out of permeable sediments, examine the seabed response to a wide range of physical forcing, and determine the pelagic ecosystem response to these processes. Detailed observations of the physical environment in the study domain are being carried out using the Kilo Nalu observational infrastructure to obtain an accurate characterization of the benthic boundary layer response to changes in physical forcing. Monitoring of the spatial variability in the physical and chemical environment is being carried out using a combination of shipboard and autonomous underwater vehicle (AUV) surveys, supplemented by satellite based remote sensing.
PIs: G. Pawlak, F. Sansone, E. De Carlo, M. McManus, A. Hebert, T. Stanton
Keyphrases: Ocean Observing, Turbulent Fluxes, Boundary Layer Dynamics, Benthic Exchange
Sponsor: National Science Foundation Coastal Ocean Processes (CoOP) program (2005-2008)
Coastal Form Drag and Eddies
This project uses field observations and numerical modeling to examine the formation and dissipation of a headland eddy in deep water. Included in this is examination of the vertical structure of vorticity within an eddy and of the baroclinic response of the flow around the sloping headland. Field observations involve the use of subsurface drogued drifters to follow individual eddies and examine the horizontal dispersion pattern, along with boat-mounted ADCP and CTD surveys which measure the 3-D flow structure over the tidal period.
PIs: G. Pawlak (collaborative with P. MacCready, U. Washington)
Keyphrases: Headland Eddies, Form Drag, Horizontal Dispersion
Sponsor: National Science Foundation (2004-2007)

Effects of Offshore Forcing in the Nearshore Environment
We are carrying out a series of field observations, based at the Kilo Nalu Observatory, combined with numerical model simulations to investigate the influence of internal tides on the nearshore zone. Internal tides are ubiquitous features in the outer shelf and deep ocean (Wunsch, 1975); however, recent observations have demonstrated that these baroclinic waves can penetrate to the inner shelf, and in some settings, can drive current amplitudes that are comparable to wave and wind-driven flows. The goals of this project are to further examine the importance of internal tide variations in the nearshore, to simulate their spatio-temporal behavior, and to assess their potential influence, in combination with surface wave forcing, on nearshore sediment transport.
PIs: G. Pawlak, M. Merrifield
Keyphrases: Internal Tides, Nearshore Dynamics, Sediment Transport
Sponsor: Office of Naval Research (2006-2008)
Hawaii Tsunami Mapping Project
The State of Hawaii officially began the Hawaii Tsunami Mapping Project in January 2004. The 1475 km (915 miles) of coastlines of the six major Hawaiian Islands are divided into 28 segments for inundation and evacuation map updates. The project utilizes latest modeling techniques, demographic data, bathymetry and topography, and Geographical Information System (GIS) technology. The effort began with the Oahu North Shore segment, which has good runup records of major tsunamis during the last century. Reconstruction of these tsunamis using a two-dimensional long-wave model determines the 100-year inundation limit and flow depth. This data provides the county civil defense agencies a reference for evacuation map update. The historical runup records provide useful information for model and procedure calibration and assure the quality of the data products.
PI: Kwok Fai Cheung
Other Investigator: George Curtis
ORE Students: Megan Craw, Justin Goo, Jane Mi (MS 2006), Sophie Munger, Volker Roeber, Alejandro Sánchez (MS 2006), Yong Wei (PhD 2006), Yoshiki Yamazaki (MS 2004, continuing for PhD)
Keyphrases: Earthquake, evacuation, inundation, natural hazards, runup, tsunami
Sponsor: Hawaii State Civil Defense (2004 – 2007).
Modeling of Hurricane Winds, Waves, Surge, and Overwash at Landfall
This is an on-going research effort funded directly and indirectly by several agencies. The research over the years has developed an ensemble of interoperable numerical models that includes a suite of hurricane wind models, a shallow-water hydrodynamic model, a global tidal model, a spectral ocean wave model, a spectral coastal wave model, and a Boussinesq model. The model package describes the meteorological conditions, astronomical tides and storm surge, wave generation, propagation, and nearshore transformation, and coastal processes and overwash with a nested grid system. A web-based GIS interface is being developed to allow users to define the model domain, generate input data, build the analysis process, and view the output with other data layers. The computed wind speeds, wave conditions, storm-water levels, and inundation limits have been validated with measured data from Hurricanes Iwa and Iniki, which hit the Hawaiian Island of Kauai in 1982 and 1992, as well as Hurricane Bob, which made landfall at Southern New England in 1991. Current research includes implementation of the polynomial chaos method to provide probabilistic forecasts of hurricane impacts and coastal inundation.
PI: Kwok Fai Cheung
ORE Students: Douyere (MS 2003), Christopher Martino (MS 2000), Amal Phadke (PhD 2001), Raymond Rojas (MS 2001), Yong Wei (PhD 2006), Ge Liang
Post-doc and visiting scholars: Nicholas Dodd, Shijun Liao, Liujuan Tang, Zhixia Zhu
Keyphrases: hurricanes, natural hazards, overwash, storm surge, waves
Sponsor: NASA Office of Earth Science (1999 – 2002), Bermuda Biological Station for Research, Inc. (2003 – 2004), Office of Naval Research (2002 – 2008)
Real-time Observations of Oahu’s Coastal Environment
The coastal marine environment is a vital economic and cultural resource for the State of Hawaii. The south shore of Oahu is a focal region for the state in terms of economic importance, but is also one of the most heavily burdened in terms of societal impact with potential effects on nearshore water quality from point and non-point source (NPS) pollution from urban Honolulu. We are developing a set of observational tools based on those deployed on autonomous instrumented platforms such as CRIMP, that will enable a baseline, real-time characterization of the physical and biogeochemical environment of Oahu’s south shore.
PIs: G. Pawlak and E. DeCarlo
Keyphrases: Ocean Observing, Water Quality
Sponsor: NOAA Sea Grant College Program (2005-2007)
Validation of Coastal Wave Models for Tropical Island Conditions
The Hawaiian and other Pacific islands are subject to direct approach of large ocean swells generated by distant storms as well as high waves from tropical cyclones that impinge on the islands. The PILOT project of the US Army Corps of Engineers addresses these issues through measurements and modeling of the coastal waves on Oahu and Guam. The collected data provides a very good opportunity to evaluate and validates coastal wave models for tropical island conditions. This comparative study will identify the strengths and weaknesses of two spectral wave models, a Boussinesq model, and a nonlinear shallow-water model in describing wave transformation and breaking at tropical coasts and discuss the implications on runup calculations.
PI: Kwok Fai Cheung
ORE Students: Justin Goo, Pablo Duarte
Post-doc: Yong Wei
Keyphrases: Reefs, tropical coasts, waves, wave models
Sponsor: US Army Corps of Engineers (2006)
Wave-Driven Porewater-Seawater Exchange in Sandy Sediments
Shallow-water surface waves traveling above permeable sandy sediments can induce greatly enhanced mixing across the sediment-water interface and rapid transport of water and particles within the sediment. A key variable in quantifying this exchange is the rate of dispersion within the bed. To address this, we are carrying out field observations of wave and current driven dispersion in sandy sediments at the Kilo Nalu Observatory.
PIs: F. Sansone, M. Merrifield and G. Pawlak
Keyphrases: Benthic Exchange, Porewater Dynamics, Dispersion
Sponsor: National Science Foundation (2004-2007)