WRRCTMR No.8 Infrared Exploration for Hawaiian Ground Water Coastal Springs: A Status Report, 10 December 1966

Abstract

Ground water springs near the shoreline discharge a large portion of the Ghyben-Herzberg fresh water lens in the Hawaiian Islands. Conventional methods are applicable to measurement of rainfall, evaporation and runoff, but the irregular distribution and size of holes in the volcanic rock through which most Hawaiian water flows make accurate ground water flow measurements difficult. More precise information on the rates of ground water losses through coastal spring discharge are important to the understanding and planning for future Hawaiian water supply. A variety of reliable and economical methods of utilizing infrared radiation and reflection are being successfully applied to the study of rocks, plants, sea water and other material. Specifically, infrared radiation has been shown to be an effective indicator of fresh and sea water temperatures. A joint federal and state project funded for the year 1966-67 through the Water Resources Research Center at the University of Hawaii in part will investigate the applicability of various sensors to the measurement of thermal contrast in and around coastal ground water springs wasting into the sea. Studies will include the examination of infrared radiation spectra at various wave lenghts by films and thermistor instrumentation. Surface and underwater temperatures will be compared with radiometer measurements to determine the accuracy and water penetration of radiation sensors.