SUB-SOIL DRAINAGE.

Press, Volume LVIII, Issue 17469, 1 June 1922, Page 5

SUB-SOIL DRAINAGE.

DISCUSSED BY CONFERENCE. The question of sub-soil drainage was discussed at a conference held at the Hospital yesterday afternoon. Mr H. B. Sorensen (chairman of the Hospital Board) presided and there were also present: Messrs H. H. Ho - land (Hospital Board), W. H. Winsor and J. K. Archer (City Council), 1. Sisiion (Waimairi Council), "ft alter H ancl J. Cullen (Christchurch Drainage Board), I>r. Pearson (Bacteriologist, Christchurch Hospital). Mr H. H. Holland opened the conference by moving: "mat the oc bodies interested ask the Drainage Board to assist to remove or alleviate anv danger that might exist m reiartion to subsoil drainage." The motion was seconded bv Sorensen. . , Dr. Pearson said that efficient subsoil drainage would be of l >enefit to the community. Christchurch built upon a swamp and the dampness prevailing could be remedied by system of sub-soil drainage and more favourable conditions would prevail. It was not proved that a damp sol would or itself give rise to disease, but damp soil and houses would the liability of the people to bacterial diseases, especially those ot the clie -*'- Consumption was not the only chest trouble one had to consider. me minor chest troubles were more potent in opening up the way for fu i trouble. The number of ca ~ es phthisis appearing in the North Canterbury district indicated not so mucn that the trouble was more acute Here as that the system of observation ana treatment was more efficient. As i ar as bacterial rheumatic conditions were concerned, he did not think he had ever been in a town of this size where he had seen the disease so prevalent. Dampness could not give rise to tnat disease of itself, but would lower vitility and allow the disease to get into the system. Poor local conditions were associated with poor drainage. Another class of disease which was largely influenced by sub-soil drainage were the bacteriological diseases or the bowels and particularly typhoid. In European countries it was shown that tvr-hoid was largely influenced by the nature of the soil. Theie Tias little soil contamination from s ) en j € . r " &",e in Christchurch itself but with the growth of the city that soil pollution might become more dangerous. It would certainly be a prudent measure to reduce the water content of the S °Mr Walter Hill asked what depth it would be necessary to dram the land to make conditions healthy. Dr. Pearson said that local conditions varied considerably. In many cases. the present level of the Drainage Board's drains would be sufficient; m other cases a deeper level would be required. It would then bo necessaiy to pump the outfall-drain water away. Mr K H. Holland asked if children living in a wet locality were more likely to develop diphtheria than children living in a dry areaDr. Pearson said that diphtheria was more'likely to spread among children by carriers at the schools rather than directly as a result of living in a wet locality. Mr H. H. Holland asked whether there would be a reduction in sickness if the city and suburbs were reasonably drained. Dr. Pearson: I think so, undoubtedly, but it will not stamp disease out altogether. In reply to another question, Dr. Pearson said there was little evidence 6i: sewerage pollution of the soil. Mr Walter Hill said he agreed that it would be beneficial to the city and district if the water level could be reduced. In the northern part of the city water was located_ at from one to three feet below the surface. The Drainage Board's sewers undoubtedly took away «i quantity of the subsoil water. Millions of gallons of water were pumped per week which was all subsoil water. As to pollution o:E the soil, it was impossible in all case.s to make earthenware pipes laid through quicksand, and in other difficult ways, intact and free from leakage. The Drainage Board would be pleased to assist in any scheme that might be formulated, and would place the services of its engineer at tho disposal of the Conference. Cr. W. H. Winsor said that if there was any possible way of getting rid of subsoil water it should be adopted by th 9 community. The city was really built on the wrong siteIt should have been built on the hills. He was surprised to hear that 1 Christohurch compared unfavourably with other cities in the matter of health. Dr. Pearson: I was speaking of infectious diseases only. Mr Sorensen: The general health is Jill right. Dr. Pearson: There are no means of getting at. the general health of the community. Cr. J. K. Archer said the present system of sewers was simply a source of contamination. The town should be drained with main drains, all watertight. Mr Walter Hill said that every yard of sewer put in was first tested under pressure, but the vibration experienced was such that concrete and earthenware pipes would | not stand it. Any bad spots located were replaced with iron pipes, but it would be a vast undertaking to examine the entire system in oraer to test the mains for leakage. The chairman said the local bodies should agree to assist the Drainage Board in its endeavour to remedy the trouble. He understood the difficulties involved in draining the city, which in the early days was on absolute swamp. He had nearly lost a horse and his own life in a quagmire in the North Belt in the early .days. Cr. J. IC. Archer suggested thai measures should be taken to prevent the extension of the city to waterlogged areas. The motion was carried. Mr H. H. Holland then moved: "That this conference approves ot and recommends the City Council, the Waimairi Council and the Kiccarton Council to make regulations or by-laws: (a) That it be an obligation upon the owners of all new sub-divisions to apply to the body in control of drains for a. report on the drainage requirements of the proposed sub-di vision; (b) any drainage requirements must be agreed to before any street formation is approved. The report to be made at the expense of tjie owners of the proposed sub-divisions." The motion was seconded by Cr. J. K. Archer. Mr Walter Hill asked ,if it would be a detriment to public health if the sewers were laid below the usual water level of the plains. Dr. Pearson: That is difficult to answer off hand. A water-logged soil is not as readily polluted as a gravel soil. So far we have had no marked evidence by disease at any rate that our city is polluted. It is a city particularly free of diseases that are brought about or influenced by sewerage pollution. The motion was earned and the conference adjourned.