Summary of soil field-saturated hydraulic conductivity, hydrophobicity, and preferential-flow measurements and soil laboratory-testing results collected at three sites on the islands of Maui and Hawaii, Hawaii, July 2016-January 2018

The U.S. Geological Survey Pacific Islands Water Science Center and the University of Hawaii at Manoa Department of Geography, in cooperation with the U.S. Department of Interior Pacific Islands Climate Adaptation Science Center initiated a field data-collection program as part of a study to quantify the impacts of drought on water resources and the importance of cloud-water interception in mitigating the impacts of drought (see Related External Resources link below). The goal of the data-collection program is to provide information for evaluating the role that cloud-water interception in Hawaii's rain forests has in providing moisture for plants, reducing wildfire risk within the fog zone, and contributing to groundwater recharge to aquifers that supply drinking water and persistent groundwater discharge to streams even during dry periods. The overall objective of the study is to provide needed information (1) to estimate changes in soil moisture, evapotranspiration, and groundwater recharge during periods of drought for current and projected climate conditions, and (2) to estimate the combined impact of drought and reduced cloud-water interception on soil moisture, evapotranspiration, and groundwater recharge.

This dataset includes a summary of soil particle-size, dry bulk density, porosity, volumetric water content, and gravimetric water content analyses made on soil samples collected at three study sites, one on the island of Maui (Nakula) and two on the island of Hawaii (Laupahoehoe and Nahuku) between July 2016 and July 2017. The dataset also includes a summary of measurements of soil field-saturated hydraulic conductivity, hydrophobicity, and preferential flow collected at the Nakula site during January 2018. Each study site consisted of one plot located in forested land within the cloud zone. In addition, the Nakula study site included a second plot located in grassland adjacent to the forested plot.