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Coastal vulnerability assessment of Channel Islands National Park (CHIS) to sea-level rise

March 30, 2021

A coastal vulnerability index (CVI) was used to map the relative vulnerability of the coast to future sea-level rise within Channel Islands National Park off the coast of California. The CVI ranks the following in terms of their physical contribution to sea-level rise-related coastal change: geomorphology, regional coastal slope, rate of relative sea-level rise, historical shoreline change rates, mean tidal range and mean significant wave height. The rankings for each input variable were combined, and an index value calculated for 1-minute grid cells covering the park. The CVI highlights those regions where the physical effects of sea-level rise might be the greatest. This approach combines the coastal system's susceptibility to change with its natural ability to adapt to changing environmental conditions, yielding a quantitative, although relative, measure of the park's natural vulnerability to the effects of sea-level rise. The CVI provides an objective technique for evaluation and long-term planning by scientists and park managers. Channel Islands National Park consists of sand and gravel beaches, rock cliffs, and alluvial fans. The areas within the Channel Islands that are likely to be most vulnerable to sea-level rise are areas of unconsolidated sediment where regional coastal slope is low and wave energy is high.