FLOODING OF CAMP

Evening Post, Volume CXXV, Issue 80, 5 April 1938, Page 12

FLOODING OF CAMP

EAST COAST DISASTER

ENGINEER'S EVIDENCE

SPOIL IN STREAM

(By Telegraph—Press Association.)

WAIROA, This Day.

. The. inquests on the victims of the Public Works camp disaster in the Kopuawhara Valley on February 19 were continued today before the Coroner (Mr. V. E. Winter).

The first witness was Edward Walpole McEnnis, engineer in charge of the railway construction works at Kopuawhara.

During the course of the engineer's evidence the Coroner stated that so far as he was concerned the dumping of spoil from the No. 6 tunnel had nothing to do with the disaster.

McEnnis said that the camp known as No. 4 was in existence before he went there. It was established in 1930 and comprised roughly 50 huts and tents, together with a cookhouse, bathhouse, and carpenter's shop. It was situated on the right bank of the stream. On. the evening of February 18 there were 42 men in camp, also two women and two children. The camp was ; situated on level ground about 12 or 13 feet above the normal water level. He had never heard of the stream breaking over its banks before. What we're looked upon as serious floods in the past would not mean more than a 4ft rise in the river. The two camps known as No. 3 and No. 5 were situated on either side of the camp. The road crossed the stream at No. 4 camp by a bridge approximately 80 feet long. The deck level of the bridge would be approximately level W|ith the camp site. With the average winter the flow would be about "eight feet between the water level 'arid the girders, and the width of the stream would be at least 80 feet. The grade of the channel was fairly steep, the country which the stream drained-being steep, grassgrown hillsides and fairly harrow valleys. There was a negligible amount of forest.1 Witness understood that the'i deforestation dated back 40 or 50 years. There were four or fiye rain tributaries. I

NO CAUSE FOR CONCERN.

During February 18 the rain was intermittent, being heavier'during the evening. Witness saw the stream, about '4 p.m. If was dirty, with a slight rise. He awakened about 3 a.m. Tlie rain was then very heavy: * When, he saw the stream in the' evening it did not give cause for concern! After the flood he saw some girders of the bridge, bolted together and weighing over five tons, some chains down the river. He was first advised, of the tragedy about 7.30 in the morning and he sent two assistant engineers to report on the conditions there. Search parties were sent out, there being plenty of volunteers. The banks of the stream were scoured, also the area covered by the flood. Other parties were detailed to make access roads passable. -

The upper watershed on investigation bore .evidence of heavy scouring and/heavy slips. He estimated that 200,000 yards of material had been scoured away. Heavy logs and timber were scattered over the banks of the stream, some of the .logs being thirty feet in length and three feet in diameter. There was heavy silting from No. 3 camp downwards and lighter silting farther up. Witness had never seen driftwood beyond two inches in diameter come down in floods previously. He did not know any parts of the river,where an obstruction could occur. He had heard it said that the dumping of spoil from No. 6 tunnel might have caused, the disaster. The high-water mark near the tunnel after the flood disclosed a rise of nine feet. It was higher/ farther down. If the water had, wanted to it could have gone up another chain and would not have been impounded even then. He considered that the camp was safe and well chosen and had never had any complaints about it. , ■ Beyond saying that it was phenomenal rainfall, he could not say what had caused the flood. -.■..., ' i

RECORD OF RAINFALL.

To Mr. L. W.. Willis, representing the Public Works Department, witness said that the record of the rainfall from 7 p.m. on February 18 to 5 p.m. on February 19 showed §.08in. The work of boring the tunnel had been proceeding for about 18 months. When the boring started the spoil was dumped on the boulder bed of the stream but not, in the water.* When they started dumping the distance from the road to th£ running water at the; corner where the spoil "was dumped was approximately 100 feet. The spoil was dumped \to a height of nine feet.. At this stage the Coroner said He would like It to be known that he was satisfied the dumping of spoil had nothing whatever to do with the disaster. V Witness added that the rise in the level of the river at the Ijuhnel was nine feet, showing that the water took the opportunity of spreading.

The spoil consisted of sandstone scrapings with a heavy proportidn of fine material, witness continued. All but a small percentage of the boulders in the dump would be ground up by the action1 of the hard boulders in the river bed. The maximum discharge of the stream ' was 21,400 cusees. Calcu r lations showed that the spoil in the dump would probably disappear in about three months. From his observations there was nothing to show that there had been any damming in the stream. There t were several tributaries running into the stream between No. 4 camp and half a mile above the tunnel, and their combined discharge would be about 7000 cusecs.

Witness said that a totara tree was some months ago cut from the camp site and portions were preserved. A section was examined by an orchard instructor from Gisborne, who estimated that the life of the tree was not less than 85 years. It was presumed, therefore, that the age of the ground where the tree grew was considerably in excess of 85 years. During an inspection of the country by air he saw a number of, scars in the hills, and many of them were abnormal in size. The bush was felled fifty or sixty years ago, and so far as he knew there had been no similar erosion since the bush was felled.