Hydrology and Chemistry of Ground Water a in Puna, Hawaiia

Abstract

ABSTRACTPresented is an analysis of the hydrology and chemistry of the ground water of the Puna District, Hawaii, based on data from 16 drilled wells, ten test wells, two shafts and four exploratory thermal wells. Ground water occurs as (1) perched water located north of Mountain View; (2) dike water located along the east rift zone of Kilauea, and (3) basal water occurring throughout most of the district, except where dike water is present. The east rift zone serves as a barrier to ground‐water movement, as demonstrated by the difference in basal water‐table levels on the two sides of the rift zone. Salinity and temperature of the basal ground water varies greatly north and south of the rift zone due to differences in precipitation, sea‐water intrusion, volcanic activity, flow rates, permeability, and discharge.Basal ground‐water type is predominantly sodium chloride. Water samples taken from thermal test well no. 3 showed dissolved silica values two to three times higher than the 49 mg/l average for the rest of the island. Hydrologic and geologic conditions in and around Kilauea's east rift zone support the possibility of accumulations of superheated ground water. The mixing of waters of different composition at depth proved to be the most difficult problem encountered in estimating deep groundwater temperatures.