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Chapter 3 – Issues with the Shoreline Certification Process The objective for this Chapter was to: “Determine the shoreline or identify a methodology to determine the shoreline in the study area. These recommendations shall consider the economic, environmental and legal ramifications resulting from the existing and potential expansion of residential development and seawall improvements within the study area. One important difficulty to consider in determining the shoreline for this area is that the episodic and continuous subsidence has allowed the ocean at high water levels to interfinger with existing development. As one moves along the coast, the level of development changes, as well as the elevation, and thus the level of inundation. All of this serves to complicate potential solutions. In order to gain insight into the shoreline certification process, and other shoreline issues at Kapoho, numerous field trips were made to the site. 3.1 Field Trip – August 17, 2005 A field trip was made on August 17, 2005, to the Kapoho Vacationland Subdivision. Present on that day were Dennis Hwang, Dr. Ben Brooks, Dr. Chris Foster, Larry Brown from the Hawaii County Planning Department, geology graduate student Chris Conger, and local resident Eric Schott. The team was there to observe the high tide predicted on the NOAA tide charts for Hilo to be at 3.1 feet above Mean Lower Low Water (MLLW) at 2:15 pm. This was one of the highest tides of the year, as only one day in June, three days in July and two days in August had higher predicted tides in 2005, with the maximum in 2005 being at 3.3 feet above MLLW. The purpose of the trip was not to identify the shoreline as defined, but to observe one of the higher tide events for the year, which would provide insight on methodologies to identify the shoreline in this difficult area of study. Some observations from the field trip were: Accretion - There was no sign of active accretion of sand along the coastline. The coast is made of rocky material (pahoehoe lava rock) and thus accretion, such as occurs on some sandy beaches in the State by the buildup of loose sediment was not present. The area to the east of the Kapoho Vacationland and Kapoho Beach Lots subdivisions did experience lava accretion by the 1960 lava flow (Figure 2-4). The possibility of episodic accretion by lava remains and the Hawaii Volcano Observatory should be consulted regarding the risks for this particular area. Subsidence Rates - The major information on subsidence rates is derived by previous studies, prior measurements of nearby areas, and a current study 17