Mean annual groundwater recharge rates for Kauaʻi, Oʻahu, Molokaʻi, Maui, and the Island of Hawaiʻi, for a set of drought and land-cover conditions

These shapefiles represent the spatial distribution of mean annual groundwater recharge, in inches, for Kauaʻi, Oʻahu, Molokaʻi, Maui, and the Island of Hawaiʻi for a set of water-budget scenarios that characterize unique combinations of drought and land-cover conditions. Two water-budget scenarios were developed to quantify the effects of severe drought and future climate conditions on groundwater recharge for each island as follows: (1) rainfall conditions representative of the driest conditions during 1920–2012 and 2020 land cover, and (2) rainfall conditions representative of the driest conditions during a future dry-climate condition and 2020 land cover. Each drought condition was combined with two hypothetical land-cover conditions to produce four additional water-budget scenarios each for Oʻahu, Maui, and the Island of Hawaiʻi, which enabled evaluation of the added effects of reduced cloud-water interception on groundwater recharge. The four additional scenarios were: (1) rainfall conditions representative of the driest conditions during 1920–2012 and Conversion 1 land cover, (2) rainfall conditions representative of the driest conditions during 1920–2012 and Conversion 2 land cover, (3) rainfall conditions representative of the driest conditions during a future dry-climate condition and Conversion 1 land cover, and (4) rainfall conditions representative of the driest conditions during a future dry-climate condition and Conversion 2 land cover. The future dry-climate condition is a Representative Concentration Pathway projection during 2071–99 with a total radiative forcing of 8.5 Watts per square meter by the year 2100 (RCP8.5 2071–99 projection) described in Elison Timm and others (2015). Conversion 1 land cover is a hypothetical land-cover condition in which roughly 50 percent of shrubland and forest areas within the cloud zone are converted to grassland, for which cloud-water interception is considered to be negligible. Conversion 2 land cover is a hypothetical land-cover condition in which 100 percent of shrubland and forest areas within the cloud zone are converted to grassland. Groundwater recharge for each model subarea was computed for each scenario using the water-budget code known as WATRMod, a Water-budget Accounting for Tropical Regions Model (Oki, 2022). The shapefile attribute information associated with each subarea present an estimate of mean annual groundwater recharge, and select geographic and land-cover attributes. Brief descriptions of the groundwater recharge estimates and attributes are included in the metadata files. Refer to Mair and others (2024) for further details of the methods and sources used to determine groundwater recharge and the attributes.