AN UNSAFE DAM

Evening Post, Volume CXXIV, Issue 60, 8 September 1937, Page 11

AN UNSAFE DAM

WALL TO BE LOWERED

FLOOD PRESSURE RELIEF

(From "Tho Post's" Representative.) SYDNEY, September-2.

Following the discovery a month ago of cracks in the wall of the Burrinjuck Dam (N.S.W.), which might result in a major disaster in the event of a flood, the height of the wall is to be lowered by from 10ft to 15ft to make it safer.

When the faults were discovered the State Cabinet empowered the Premier (Mr. Stevens) to spend any money considered necessary by experts to make the structure sounder. Reports by London and Sydney engineers resulted in the decision to . lower the height of the dam wall at a cost of £100,000, this being the first stage of the complete reconditioning, the cost of which has not yet been estimated. Professor F. D. Hornell, of Sweden, a recognised world authority on the reconditioning of such structures, has been engaged to plan and supervise the work. From 150 to 200 men will be employed for three months.

"The position disclosed by the consulting engineers' reports," said Mr. Stevens, "is such that the Cabinet has decided to take immediate measures to reduce the risks thai; would be incurred in the event of a flood similar to, or exceeding that, of May, 1925. The 1925 flood exceeded any estimates that previously had been made during the design and construction of the dam, and investigations made at the time, and since, render it advisable for the dam to be reconditioned with more ample provision for flood discharge than exists at the present time. The cutting-off of a portion of the top of the dam will have two major effects. The actual- water pressure on the face of the dam will be relieved to an extent equivalent to the reduction in height, and in the event of major floods, water will be discharged over the crest with a minimum of shock to the structure. The consultants state that the maximum storage capacity of the dam will not be affected, as the level of the crest will still be above the level of the existing spillways, and the value of the reservoir for irrigation purposes, therefore, will be maintained. The effect of the discharge of flood water over the crest, as well as through the spillways, need cause no apprehension in the minds of people downstream of the dam, as the level of the waters downstream will not be affected to an extent of more than two feet near the dam, and to a lesser extent further down the stream."

A start already has been made towards assembling the necessary plant and equipment to carry out the surveys and investigations for the purpose of protecting the power-house below the dam and to provide the data on which designs for permanent remedial measures may be based.

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