Technical Report No. 68
William M. Adams, Richie D. Huber
For a proposed reforestation of the canyon country of east Lanai, seedlings will be required. The seedlings could be grown in east Lanai, preventing the stress of transplantation from a different environment, if an adequate source of high-quality water were available. This study was designed to locate such a source; more specifically, to find optimal sites at which to drill for fresh water. Reconnaissance work in the field took place in July 1970. At 176 places along the eastern coastline, shallow observation wells were dug at the high-tide level during low tide. The temperature and salinity of the ground water there were measured. In most of the canyon gulches, electrical resistivity soundings of the Schlumberger configuration were made. Through analysis of the field data two sectors were identified on the eastern coast: the northern sector, from Federation Village to Lopa, and the southern sector, from Lopa to Naha. Evidence points to the southern sector as being the most promising region for drilling, and specific sites are suggested. However, while the southern sector is superior for the accumulation of ground water, its beach rock is more impermeable than that of the northern sector; hence the southern sector provides less favorable conditions for recharge of the water table. Thus, the southern sector should be developed if a relatively small amount of high-quality ground water is desired from many holes closely spaced along a line–as for the irrigation of seedlings. Should a relatively larger amount of lower quality ground water be preferred, exploitation of the northern sector would be appropriate.