Table 1.

Multi-Mechanism Flooding Extent. Areas of single and multi-mechanism flooding within the study area encompassing Honolulu’s primary urban center consisting of direct marine inundation (MI), storm-drain backflow (DBF), and groundwater inundation (GWI) at four flood thresholds: KT2017, minor, moderate, and major flood thresholds⁵.

Flood Type	GWI Only		MI Only		DBF Only		Double Mechanism GWI and MI		Double Mechanism GWI and DBF		Double Mechanism MI and DBF		Triple Mechanism GWI, MI, DBF
	Area Inundated (km2)	% of Total	Area Inundated (km2)	% of Total	Area Inundated (km2)	% of Total	Area Inundated (km2)	% of Total	Area Inundated (km2)	% of Total	Area Inundated (km2)	% of Total	Area Inundated (km2)	% of Total	Total Area Inundated (km2)
KT2017	0.19	26.33	0.02	2.39	0.00	0.40	0.31	41.98	0.07	10.10	0.00	0.65	0.13	18.15	0.73
Minor	0.24	23.32	0.03	2.66	0.01	0.84	0.38	36.65	0.17	16.14	0.01	0.95	0.20	19.43	1.04
Moderate	0.63	24.74	0.06	2.31	0.10	3.74	0.50	19.56	0.19	7.52	0.08	3.17	0.99	38.95	2.54
Major	1.19	15.19	0.28	3.61	0.04	0.55	1.37	17.55	0.18	2.35	0.47	6.05	4.27	54.71	7.81