East Maui Isotope Hydrology Research
Scholl, M.A., Gingerich, S.B. and Tribble, G.W., 2002, The influence of microclimates and fog on stable isotope signatures used in interpretation of regional hydrology: East Maui, Hawaii, Journal of Hydrology, v. 264, no. 1-4, p. 170-184 (document in .pdf format).
ABSTRACT: Stable isotopes of precipitation, ground water and surface water measured on the windward side of East Maui from 2 to 2984 m altitude were used to determine recharge sources for stream flow and ground water. Correct interpretation of the hydrology using rainfall oxygen-18 gradients with altitude required consideration of the influence of fog, as fog samples had isotopic signatures enriched by as much as 3 ‰ in oxygen-18 and 21 ‰ in deuterium compared to volume-weighted average precipitation at the same altitude. The isotopic analyses suggested that fog drip was a major component of stream flow and shallow ground water at higher altitudes in the watershed. Oxygen-18 / altitude gradients in rainfall were comparable for similar microclimates on Maui (this study) and Hawaii Island (1990-95 study), however, East Maui oxygen-18 values for rain in trade-wind and high-altitude microclimates were enriched compared to those from Hawaii Island (see figure below). Isotopes were used to interpret regional hydrology in this volcanic island aquifer system. In part of the study area, stable isotopes indicate discharge of ground water recharged at least 1000 m above the sample site. This deep-flowpath ground water was found in springs from sea level up to 240 m altitude, indicating saturation to altitudes much higher than a typical freshwater lens. These findings help in predicting the effects of ground water development on stream flow in the area.
Supplementary Data Tables
Stable isotope data tables for precipitation and groundwater from East Maui, Hawaii.
Precipitation isotope data:
Ground water and surface water data:
Gingerich, S.B., 1999, Ground-water occurrence and contribution to streamflow, Northeast Maui, Hawaii, U.S. Geological Survey Water-Resources Investigations Report 99-4090, 69 pp, link to report.
Gingerich, S.B., 1999, Ground water and surface water in the Haiku area, East Maui, Hawaii, U.S. Geological Survey Water-Resources Investigations Report 98-4142, 38 pp, link to abstract.
Meyer, William, 2000, A Reevaluation of the occurrence of ground water in the Nahiku area, East Maui, Hawaii, U.S. Geological Survey Professional Paper 1618, 81 pp.
Shade, P.J., 1999, Water budget of East Maui, Hawaii, U.S. Geological Survey Water-Resources Investigations Report 98-4159, 36 pp, link to abstract.
U.S. Department of the Interior, U.S. Geological Survey, Reston, VA, USA