Onslow Bay, NC, Lessons Learned
The Onslow Bay project began in 2009 in conjunction with the development of the very first draft code of GenCade. The project itself was the first application of GenCade and has served over the years as the go-to case to test any new features or capabilities with real-life scenarios. The Onslow Bay area has proven to be a very difficult area to model and in that sense has provided the GenCade development team an opportunity to test any changes to the code. This case has helped make GenCade more robust. The project was completed in July 2012, a few months after the official release of GenCade V1. This article will highlight the lessons learned and aspects of the project that were not discussed in the official documentation. The project was discussed in this CHETN and further detailed in this Journal article (not yet published). In addition the final presentation prepared for the Wilmington District provides more figures and hypothetical scenarios.
Background
Onslow Bay in North Carolina, is a crescentic series of barrier islands covering more than 100 miles of beaches between Cape Lookout and Cape Fear (figure 1). The curvature of the Bay is very pronounced resembling a quarter circle; the curvature was one of the first obstacles encountered during the setup of the model and is further discussed in the Multiple Grids chapter.
The narrow barrier islands are separated by 11 inlets, most of which are unstructured and migrating. The first step of the study was to conduct a literature review of the area; the process is further described in the Book Keeping and Data Management chapter.
Of the 11 inlets, only Beaufort and Masonboro Inlets are structured. To the north to the Bay, Beaufort Inlet is a large federally maintained deep draft channel supplying Morehead City Harbor. Because the area is well studied and politically sensitive, it has required special attention during the calibration process which will be further detailed in the Beaufort Inlet section.
The southern portion of the bay also had its fair share of challenges mostly due to the variation in the bottom geology. The strategy to overcome this issue is described in the Underlying Geology section.