Christchurch Drainage Board: INTERNATIONAL

Press, Volume CIX, Issue 32032, 5 July 1969, Page 18

Christchurch Drainage Board: INTERNATIONAL

Installing Sewers After a decade during which the Christchurch Drainage Board gave absolute priority to sewer installation, last year it decided to lay much greater emphasis on its flood relief programme because of the problems that have arisen and grown steadily worse as large areas of land have been given over to housing. The change in emphasis has been made possible because planning of the major unsewered areas within the urban fence has been completed, although there are many small and isolated pockets of development which still require sewering, the cost of which will amount to some $1.5 million. Many flood relief measures will have to await the results of detailed investigation and until these are known and an over-all solution worked out in detail, no advances can be made in certain areas. The board, therefore, is endeavouring to deal with as many self-contained problems as possible. In most cases the full benefit of such work will be felt immediately. In others there will be additional significant improvements after major > works in the rivers or estuary have been carried out in later years. As many Christchurch ! people know only too well, I flooding can cause loss and 1 inconvenience. But there are | other aspects of the problem i that make early relief essen- j tial. Local flooding of streets and i homes overloads sewer mains ; and treatment facilities be- i cause the stormwater enters ■ the sewer system. The average daily flow at j the Bromley treatment works is between 22 and 24 million gallons. It drops off to between 19 and 20 million gallons during dry Weather, but will increase to between 36 and 39 million gallons after continuing wet weather. Thus flooding decreases sewer capacity and makes it impossible to make further I connections in certain areas. I It also adds greatly to I pumping costs and to the I hydraulic loading at the treat-1 ment works. " This year the board’s elec-1 tricity bill for pumping sta-1 tions will be at least $78,550.1