In collaboration with the County of Hawai‘i Department of Water Supply (DWS), we identified three priority management areas on Hawai‘i Island: Kohala, Kona, and Kaʻū. These critical recharge areas were identified by DWS as important recharge areas for four aquifers where current withdrawals are near current or future sustainable yield limits: Mahukona, Waimea, Keauhou, and Kealakekua. We then developed a statistical model to assess how land cover change would affect evapotranspiration and subsequently groundwater recharge—building off existing evapotranspiration, climate, land cover, and recharge datasets—to identify areas of high potential recharge benefits within the priority areas following forest protection activities. Cost data from nearby watershed management units were used to calculate average management costs for each priority area, and then were combined with the potential recharge benefit map to generate a map of cost-effectiveness.
