LAKE TAKAPUNA WATER.

Auckland Star, Volume LIV, Issue 267, 8 November 1923, Page 7

LAKE TAKAPUNA WATER.

GEOLOGIST'S REPORT. A WATERTIGHT BASIN. NO DANGER OF SALINITY. The report of the Director of Geological Survey of the Mines Department, Mr. P. G. Morgan, regarding the strata between Lake Takapuna and the seashore was referred to at the Birkenhead ■ Borough Council last night with considerable satisfaction. The Mayor (Mr. K. C. Walton), who Is the Birkenhead representative on the Board of Control, said it was very gratifying to know that this survey virtually removed the bugbear of the sea percolating into the lake in the event of the level falling below high-tide mark. The investigations fairly established the fact that the country between Uie lake and the sea was watertight, and therefore the lake could be lowered below sea level. This safeguarded the position of the water supply for some time to come. The original idea of diverting the Lower Wairau stream into the lake could not now be regarded as an urgent measure; there was happily no necessity to put an impure supply into the lake. When the need arose for an additional supply, he hoped that a comprehensive scheme would bo ready to supply all needs for many years ahead. Members inquired if the board would now abandon the Lower Wairau project, but Mr. Walton said he could not definitely slate the board's policy, as there had i>;-en no meeting for some time. He sincerely hoped that the scheme would lie dropped absolutely, as it was as undesirable as it was unnecessary. Mr. Morgan's Report. Tn the course of his report. Mr. P. .G. Morgan stated:—"Lake Takapuna is a nearly circular basin, with a shallow bay at the north-east corner. It has nn" area of 270 acres, and a maximum depth, when at its highest level, of about 200 feet. No streams run into it, but it receives the surface drainage of about 200 acres of land, and is evidently fed to some extent by springs. As is well known, the lake occupies an explosion c-rater. It has been used as a source of water supply since 1895. In that year 19,000,000 gallons of water were pumped from the lake; in 1922, approximately ■>0 1,000,000 gallons. The population of

the district supplied lias greatly increased fiiK-o 1805, and is still rapidly increasing. In 1910 it was 14.40G; in 1921 it was 17,22: i, and is now estimated at 18,400 "Owing to variation in rainfall and rate of evaporation, the amount of water obtainable from Lake Takapuna in any one year is variable. When the lake is high there is considerable leakage; when it is low there may be some leakage, but almost certainly not a great deal. The data and other information at my command do not enable mc to make a very good estimate, but in an average your the available water supply I si-ems to be somewhat over 150,000,000 pUlonn, .md .1 will assume that it is 100.000,000 gallons. The daily supply to a population of 18.400 on this basis I would be between 24 and 25 gallons, ] which is insuflieient for modern requirements. Not less than fifty gallons per I inhabitant per <liem is required in a I climate like Auckland. Evidently ever since the population served leached 9000 or 10,000 —that is, for the last twelve years or more—the Takapuna supply lias been insufficient, and the necessity for an additional supply urgent. The subject has been much discussed, and several reports on possible sources of water supplies have been obtained, but none of the schemes suggested has yet been adopted. The Rangitopuni stream lis at present favoured for a permanent I supply, but since it will be at least six years before its water can be brought ' into the Dcvonport-lVkapuna district , those concerned hope that Lake Takapuna can be used as a reservoir, and lowered below sea level without an influx of sea water taking place. An Impervious Silt. "The surface rocks round Lake Taka puna are loosely compacted tuff ant scoria, underlain in many places by i flow of basalt. The popular view, verj naturally—and one more or less held bj myself until my recent examination —i: that if the lake were lowered below ses level, seawater would begin to flow in On examining the lake and its surround ings, in company with members of thi Board of Control, Mr. F. E. Powell (con suiting engineer), Mr. Bodell (the towr clerk of Takapuna), and Mr. J. A. Bar ■ trum (lecturer on geology, Aucklam University College), I ascertained tha the basalt was underlain at many points 'by a watertight silt of clay. This silt almost certainly, is underlain by tin Waitemata beds, which in the main an

playstones with more or less line sand, and are practically watertight. Thus, as suggested to mc by Mr. Bartrum. the lake is probably not in communication with the sea by porous beds lying below sea level, but may be regarded as a watertight hole, which may be pumped below sea level without salt water flowing in. If this is so, the level of the lake ( can safely be reduced below that of the i sea. i '"While the Rangitopuni or other scheme of water supply is being brought into operation, it is proposed, if necessary, to divert into the lake water from I the YVairau Stream, which drains the country to the west of the lake and flows into the sea not far to the north. Th« situation is such that' I cannot take ii on myself to advise whether it is neees sary to obtain a. temporary supply ol wdtcr from the Wairau Stream while the . Rangitopuni or other permanent supplj I is being- brought in; but T must urge ths I desirability of obtaining a supply ol pure water without delay,.from a source or sources sufficient for the needs of r in.rsrc population, jso more i-elitxncc ouetiil ito be placed upon Lnke Tpl<anuna as s source of water than circumstance; compel. ! A WONDERFUL ELEPHANT. - I Ever eince Adam fell in love with his rib, there 'have been unnumbered ex ponenta of the art of perfect loving all in the human realm but none, in eluding , Mark Antony ajid Romeo, dis played a more sympathetic and appeal ing brand of affection than does 'Oscar," the elepliant in this remark able picture. Of course, "Oscar" ha. , the necessary inspiration, because petite Madge Bellamy plays opposite him. And how nobly he responds whei ' danger threatens Madge! In a series of delightful episodes, beginning wit! circus scenes, moving to the Oanaxli&r North Woods, and ending , wifch ai ivy-covered cottage, and a cradle foi "Oscar" to rock, this strange pair wil '. simply fascinate. The picture is a ran ] novelty. The cir<-us Scenes will and entertain the children. Parent: are strongly recommended to send then to see '"The Poul of a Beast" com menring at the Strand Theatre to morrow. Alter school cession each da .