Coupling of Wave and Circulation Numerical Models at Grays Harbor Entrance, Washington, Usa

The interaction of waves and currents at an inlet entrance can be significant. Traditionally, numerical modelers have separated the processes of tidal circulation and wave transformation, but the surf zone and inlet are areas where the interactions are strong and should be numerically simulated to capture the resulting hydrodynamics. This paper describes performance of coupled wave and circulation models for both an idealized inlet setting and an application for Grays Harbor, Washington, concentrating on the influence of waves on currents. A comparison of tidal current simulations to tidal-pluswave-induced current simulations shows that the interactions create gyres, longshore currents, rip currents, and “shadow zones” of relatively weak currents. It is concluded that accurate simulation of the hydrodynamics at coastal inlets requires coupling of wave and circulation models. INTRODUCTION Grays Harbor, located on the coast of southwest Washington, is one of the largest estuaries in the continental United States and has a correspondingly large tidal prism (Fig. 1). The entrance to Grays Harbor also experiences extreme Pacific Northwest waves. The U.S. Army Corps of Engineers (USACE) has built and maintained two rubble-mound jetties, a deep-draft navigation channel, and other navigational features in Grays Harbor. The North Jetty functions to block southward transport of sediment and to protect and maintain an entrance navigation channel; however, its effectiveness has decreased as a result of subsidence and deterioration. Recently, the north beach (Ocean Shores) has exhibited a tendency to erode, reversing a historic trend of advancement. Issues of concern 1. US Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory, 3909 Halls Ferry Road, Vicksburg, MS 39180-6199 USA. [email protected]. 2. Coastal Analysis LLC, 4886 Herron Rd., Eureka, CA 95503 USA. [email protected]. 3. US Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory, 3909 Halls Ferry Road, Vicksburg, MS 39180-6199 USA. [email protected] 4. US Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory, 3909 Halls Ferry Road, Vicksburg, MS 39180-6199 USA. [email protected]. Report Documentation Page Form Approved OMB No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. 1. REPORT DATE 2002 2. REPORT TYPE 3. DATES COVERED 00-00-2002 to 00-00-2002 4. TITLE AND SUBTITLE Coupling of Wave and Circulation Numerical Models at Grays Harbor Entrance, Washington, USA 5a. CONTRACT NUMBER