2019-09-25 Meeting Minutes (EMC)

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• Coastal erosion will affect vegetation. • There is a huge potential for loss of land, structures, and many displaced people. • On-site sewage disposal systems will be flooded. Chair Bennett said seawater infiltration is currently a big problem with the sewer lines and will cause the future R-1 water to be a little salty for successful agricultural use. In addition, many sections of the sewer lines need replacing. The rise in sea level will make the situation worse, and he wonders if it would be smarter to retreat from the coastal areas. Vice Chair Olson also expressed concerns about the sewering of Aliʻi Drive. Between the ocean rise, storm surge, and all the other things that play into it, how can the county invest money knowing there is no shelf life? Dr. Romine said detailed cost benefit studies would need to be done. It would also be helpful to talk with hydrologists to get a better understanding of the geology and what the flooding looks like underground. Private sector engineers could be brought in to assess the different scenarios and cost benefits. Dr. Romine continued with his presentation: • Slides were shown showing the potential impacts of a 3.2-foot sea level rise in Hilo, Kona, Puakō, Kapoho before it was covered with the 2018 lava flows, on Oahu’s Ewa Beach, and in urban Honolulu. • Flooding impacts include drainage failures, flooded on-site sewage disposal systems, impassable roadways, loss of structures and land, loss of critical infrastructure, and displaced residents. • The island of Hawaiʻi needs a more detailed economic loss analysis of cri?cal infrastructure. • Sea level rise adaption measures should be considered in order to provide long- term cost savings when compared to the cost of “maintaining and repairing chronically threatened public infrastructure.” • Policy and planning actions are ongoing throughout the state. • The updated State Hazard Mitigation Plan includes an assessment of coastal flood hazards with the rise in sea level. • Work is ongoing to develop guides on how to better prepare for disaster recovery, as people need to be resilient for future disaster events. Dr. Romine concluded his presentation and answered several questions. Planning Director Michael Yee addressed the commissioners and made the following points: • There is a difference between mitigation and adaptation. Mitigation sits with the Research and Development Department, while adaptation policy generally flows through the Planning Department.