LEVEL OF LAKE TAUPO

Press, Volume LXXXII, Issue 24899, 12 June 1946, Page 8

LEVEL OF LAKE TAUPO

PROGRESSIVE FALL REPORTED CAUSE NOT APPARENT (P.A.) WELLINGTON, June 11. A progressive fall in the level of Lake Tsupo, in spite of much heavy ram over the greater part of the North Island at frequent intervals during the last month or so, is believed to be causing the authorities some concern It has been suggested that abnormal seepage through large fissures which have developed in the bed of the lake may be the cause. Whatever the actual cause, it has yet to be satisfactorily explained, but it can be said that this puzzling phenomenon has made its appearance since steps were taken to raise the lake level artificially and since last year’s eruption of Ruapehu. The 31 rivers and streams which flow into Lake Taupo are said to bring far more water into the lake than flows out through the Waikato, which is the only visible outlet. The level of the lake is reported to have fallen to slightly below 1172 feet above sea level, the minimum at which control of the outflow down the Waikato river is possible. This will probably reduce the output of which the hydro-electric plants on the river are capable. The Minister in charge of the Department of Scientific and Industrial Research (the Hon. D. G. Sullivan) said that, from investigations carried Put by the Geological Survey Branch, a relationship between the raising of the lake level and the eruption was regarded as remote. The Minister added, however, that the possibility could not entirely be ruled out. even though it was considered most unlikely.

“FANTASTIC IDEA” THEORY OF FISSURES IN LAKE BED (P.A.) WELLINGTON. June 11 Expert opinion sought in Wellington to-day was emphatic that there was no scientific basis for the theory that seepage through large fissures in the bed of Lake Taupo was causing the fall m the lake level. “The idea is absolutely fantastic,” said one man closely associated with the Taupo area in relation to its part in the hydroelectric scheme. “It is simply a matter of deficient rainfall over a long period.” 5

pie statement that the flow into Lake Taupo from the rivers and streams in the catchment area of some 1500 square miles was greater than the outflow down the Waikato river was probably true on particular days, it was pointed out, but not in general. Evaporation was a big factor in the lake level, and with a large lake such as Taupo, with an area of some 240 square miles, it would probably amount to two feet in a year. Poor rainfall, a total river discharge equivalent to 25 feet a year, and evaporation were sufficient explanation for the low level of the lake. The only logical way to view the situation was over a period of months, and the plain fact was that there had not been enough rain in recent months to make any substantial difference to the level.

Rise in Level Reported “The best news we have had for months, even though it means we are still down to bedrock for water,” said one hydro-electric authority, when a fall of 129 points of rain in the 24 hours to 9 o’clock this morning was reported to him. The lake level, he said, had risen .15 feet overnight, and might rise slightly more, but it only added up to the fact that the lake level was now 1172 feet above sea level—the minimum at which control of the outflow down the Waikato river was possible. At Waikaremoana the fall has been only 70 points in 24 hours, and the position is virtually unchanged. Yesterday the lake was at 2006.7 feet, compared with 2007 feet last Thursday, and an overflow level of 2116 feet. The Mangahao area has had 2.26 inches of rain during the same 24 hours, and the dam level has risen appreciably and is continuing to rise.,