LAKE PUPUKE.

Auckland Star, Volume LXII, Issue 306, 28 December 1931, Page 8

LAKE PUPUKE.

STEADY FALL IN LEVEL. NORTH SHORE WATER • * SUPPLY. - DEVONPOE.T TAKES"'ACTIOX. Tie rapid decline in. the mean-high-water level of Lake Pupuke has caused the Devonport Council some c6ncen£;in the past few months.. This lake supplies the needs of the .. whole of the 2*orth Shore, which has a population of about 30,000. " * V ' ' V 'The Mayor, Mr. H, E. -W. Meikle, and engineer, Mr. A. T. Griffiths, made an inspection of the lake, a few days agpi As a result of the council's deliberatipns, it was deemed expedient to extend ";the intake valve a further 60ft into • -.tlie centre of the lake, and this. <Work -is almost complete. It is contended that the. extension of the pipe-line will further improve the quality of the water-.- .It was pointed out by the engineer that the lake at the deepest spot is 218 ft, and that the closer the valve is placed to the centre of the lake the purer is the water. At one period, in 1912, the lake was 13in above sea level, but it has now receded to 12in below mean highwater mark, thus making it necessary to extend the valve. The greatest depth of the lakejs on a par with the height of Mount Victoria, and it is ..therefore indicated that there is no likelihood of a water shortage for many years to come. Close to the lake's shore there is considerable organic matter, and at the time of inspection this growth was being removed. In appearance it resembled flax,, the leaves .being fully 20ft in length. It was noticed that the leaves did not in any way show deterioration, and this conveyed the "idea " that' the' water was absolutely fresh. Mr. Griffiths; said it could not be proved that the lake was fed by springs. The lake's catchment area comprised,'2oo acres, while the water' area ; itself embraced 270 acres, so with a catchment of 470 acres, the general rainfall provided all that was necessary. The idea prevailed for many years ,that wl)en s the lake's level , sea level", sea water would take poesession," but later experiences indicated, that owing to the m.

ash conglomerate round the lake being so closely : packed it was impossible for foreign - water to percolate to it. Mr. Griffiths - further said there had been some talk of the probability of a watershortage -in ; the near future,' but the lake's- deepest spot was five times deeper than any part of the Auckland harbour.

The council has made provision for a continuous supply of water to guard against the possibility of a breakdown in; the electrical plant. . The. council's reservoir holds only sufficient water for a 24-hour supply; Should any interference occur with the main plant, an auxiliary plant is capable of taking up the work within a. few hours.

Many complaints are received by the council from time to time about the discolouration of the water. In reply to a question on this subject, .Mr. Griffiths said there was nothing deleterious in the presence of iron -in -the water. The trouble-had been, greatly minimised, by the council Teplacing the mains' in certain areas. -