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Big Island East Maui Maui Fog

waterfall over basalt

Isotope Hydrology Studies in Hawaii

Investigations involving the use of stable isotope tracers to understand regional hydrology on the islands of Maui and Hawaii have spanned the period from 1991 to the present. 

On the Big Island of Hawaii, stable isotopes of precipitation and ground water were measured for three years in the area of Kilauea Volcano (1991-1994).  The spatially-dense precipitation data set revealed patterns of isotopic composition of rainfall that were closely related to microclimate differences.  The ground water isotope data helped in interpretation of regional flow patterns in and around Kilauea Volcano.  

More about the Kilauea Isotope Hydrology study...


On Maui, a follow-up study (1995-1998) was initiated to 1) test repeatability of microclimate effects on rainfall isotope patterns, and 2) aid in a study of regional hydrology and ground water/surface water interactions on the windward side of East Maui.  Changes in isotopic composition with altitude were similar for similar microclimates on Maui and Hawaii, however, the Maui data suggested that fog was an important component of the precipitation in the study area.  Stable isotopes of stream water and ground water were also used to build a new conceptual model of the regional hydrology. 

More about the East Maui Isotope Hydrology study...


A new project to investigate the role of fog in the hydrology of cloud forests on Maui began in late 2001.   The objectives of the study are to quantify the fog contribution to the water budget of windward and leeward forests, and to investigate the role of fog in the ecology of the cloud forests.  Previous work established that fog and rainfall have distinct isotopic signatures, this should allow us to track fog through the hydrologic cycle at each site.  Two sites are under investigation, one on windward Maui at 1950 m (6400 ft) altitude, and one on leeward Maui at 1220 m (4000 ft).

More about the Maui Fog study...


Methods for collection of precipitation isotopes

Link to USGS Reston Stable Isotope Laboratory


Contact information:

Martha Scholl
U.S. Geological Survey
431 National Center
12201 Sunrise Valley Dr.
Reston, VA  20192
phone:  703-648-5890
fax:  703-648-5274 or -5832
e-mail: mascholl @

link to HI District home page   Hawaii District Office, Water Resources Division - home page


Big Island East Maui Maui Fog


U.S. Department of the Interior, U.S. Geological Survey, Reston, VA, USA
Maintainer: mascholl @
Last modification: 04/01/03 15:27 (mas)

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