Infra-Red Light Reveals Fresh Water

Press, Volume CV, Issue 31023, 31 March 1966, Page 5

Infra-Red Light Reveals Fresh Water

(N.Z.P.A.-Reuter) BALTIMORE (Maryland). A new method of discovering fresh water by means of infra-red light is being developed by airborne geologists attached to the Maryland Government’s Interior Department.

By using special infra-red equipment flown over the Virgin Islands and Puerto Rico, the scientists have located hidden spots where fresh water is seeping into the sea. Infra-red “mapping” depends upon differences of heat radiation from the area to be surveyed, compared with regular photographic mapping, which uses differences of light. The infra-red map looks

somewhat like a photographic map on which the wanner areas show up as light tones and the cold areas are dark. Thus, cold spring water seeping into warm ocean waters would show up as a dark patch or stream in a light area. Water from submarine springs, which are warmer than the ocean, would show up as light ’ patches. ’ Used Over Volcanoes i The new technique was i first used last year when the . “hot spots” of the Kilauea volcano on Hawaii were mapped ’ with infra-red equipment. Not only did the films show the > temperature differences of

volcanic heat, but also th< differences of temperature ai the ground water was dis charged into the bay. Fresh water is scarce in th< Virgin Islands, and has to b< brought in barges or convert ed from sea water. In Puerti Rico, the drainage from sin! holes along the north coas may be as much as 480,000,001 gallons a day, much of whicl seeps into the ocean througl limestone caverns. By using the infra-red equip ment to discover exactl; where the fresh water dis charges into the sea, scientist can trace the fresh wate sources back into the land am drill wells to obtain it.