Water Commission Resumes Sitting

Sun (Auckland), Volume 1, Issue 31, 29 April 1927, Page 3

Water Commission Resumes Sitting

technical evidence Following an adjournment for the Faster vacation, the commission of inquiry set up by the Minister of Health to investigate the question of water supply for Greater Auckland was resumed yesterday afternoon. Mr. A. W. Blair, solicitor, of Wellington, is clmirman of the commission, and with him are associated Messrs. A. Dudley Dobson, engineer, of Christchurch, and J. A. Baker, engineer. of Wellington. Further evidence in regard to the water supply from Lake Takapuna was given by Mr. A. Harris, M.P. Mr. Harris said he was not particularly concerned with the advisability or otherwise of going to Lake Taupo or the Waikato River, but with the water supply at North Shore. As a layman he considered that the presence of a considerable quantity of weeds near the edge of the lake where the intake pipes v/ere situated, and which became considerably flyblown in the summer time, had a deteriorating effect upon the water. To obtain a clearer sample he considered it would be better to have pontoon intakes in the centre of the lake where good samples had been taken. To Mr. Rogerson: He considered that the formation of a water board would be the best method of controlling the water supply for the city and surrounding districts. SUPPLY SOURCES ANALYSED Further evidence in regard to the purity of existing and proposed supply sources was given by Dr. H. T. Chesson, representing the Health Department, who submitted detailed chemical and bacteriological analyses as follow: “Lake Takapuna.—The specimen was taken well out in the lake, clear of marginal contamination. The result shows a water of good quality, and free from bacterial contamination.. 4 Waitakere Reservoir.-—The result shows a water of poor quality in its unfiltered state, - and the presence of bacillus coll. The latter, however, I do not consider of much importance, taking into consideration the fact that human contamination is most unlikely. When filtered, no doubt this will be quife an excellent water. “Nihotupu Reservoir.—ln this case bacillus coii were present in less quantity, but other bacteria were more numerous. My comments with regard to Waitakere apply to this sample also. "Mangatangi Rivar.—ln spite of the fact that bacillus coli are present in five cubic centimetres, this is a very satisfactory water but, if used, the wa.er-shed should be taken over and kept clear of any possibility of human contamination. “Maungatawhiri River.—This is a good result, except for the presence of bacillus coli in one cubic centimetre, but if the water-shed was taken over and cleared of settlement, as I understand there is one farm on the watershed. the water could be rendered quite safe for use without chlorination. “Wairoa River.—Chemically good, but bacillus coli are present in considerable numbers, but in this case also if the water-shed is taken over and cleared it should be perfectly safe. It is quite possible the presence of a farm on its upper regions may be responsible for the high bacillus coli count. Both this and the Maungatawhiri sample were taken after there had been a fall of rain. WAIKATO SUPPLY “Waikato River at Mercer.—This is not as good a supply as the Maungatawhiri or Mangatangi, and we are aware that it receives town drainage higher up. The analytical result is rather better than one would have expected. "Waikato River at Arapuni.—The Ba j n Ple having been taken after heavy fain may account for the high count |n bacillus coli, possibly due to washings from the land sloping toward the river. "Lake Ta upo.—Recent heavy rain Probably accounts for bacillus coli oeing present in 50 cubic centimetres, inis, however, is a low count for coli, bot one would have expected absence x this organism in such a large volume of water and a sample taken well awa / from the shore.” Of all the samples, added Dr. Ches*°n. that from Lake Takapuna was undoubtedly the best, but the lake for J iher reasons was not to be depended Pon as a permanent source of sup- :‘ y - Mangatangi came next among arby sources, and Maungatawhiri subject to the clearing of the *ater-shed. 'nu^ e anal yses showed that bacillus detected in the following quantities of water from the vj. erent samples:—Waitakere, scc.; \c, Upu ’ 25cc.; Mangatangi, scc.; ce Un fr tj . nv hiri, lcc.; Wairoa. decimal ” a ikato, at Mercer, decimal scc.; aiKato, a t Arapuni, decimal scc.; ~* ke Tauno. 50cc.