Storm-Cut erosion on our Beaches
Updated: Aug 8, 2020
One of the most unnerving discoveries when walking on a beach after a storm is finding “storm-cut erosion”. We worry that the lost sand may never return. New Maui residents soon learn that this is a cyclical event which occurs every few years. When storm waves wash away part of a dune face, it can leave behind a towering cliff or wall of sand. Much of the removed sand will return over a number of weeks or months.
However, if there are back-to-back storms and the sand removed from storm #1 has not returned before storm #2 hits, that remaining wall of sand serves as the reserve or buffer between the sea and inland areas. Sometimes, the sand is depleted entirely.
It is vital to know what the size requirements are for a properly sized protective dune and to know if zone-specific native plants cover the dune face, in order to rebuild or restore it. These answers and other important dune-related science and facts are explained by the coastal geologists at UH Sea Grant who work with other state and county officials. With increasing storm activity and sea level rise, coastal communities worldwide are faced with developing a science-based plan for dune areas. This plan is often called a Foreshore Asset Management Plan. The plan prescribes protocols for erosion response and the rebuilding of dunes. With mounting pressure on our dunes, Maui County would benefit from such a plan.
Submitted as Letter to the editor and was published on December 19, 2018