WASH-OUTS AND SLIPS ON SEVERAL HIGHWAYS

Dominion, Volume 34, Issue 121, 15 February 1941, Page 13

WASH-OUTS AND SLIPS ON SEVERAL HIGHWAYS

Prolonged Wellington Rainstorm SECTION OF NGAHAURANGA GORGE ROAD SWEPT AWAY

As a result of the most severe rainstorms since the second week of December, 1939, damage which will cost thousands of 0 make good has been done to main highways leading from \\ ellington. In two and a half days up to 9 o’clock last night the rainfal at the weather bureau at Kelburn was twice the average lor the month ° f F The Ua greatest damage has been done in the Ngahauranga Gorge Road A section of this new double-lane highway, which lanks among the finest of its kind in the Southern Hemisphere, has been swept away for 70 yards. The entire width of one side of the road, carrying traffic one wav, has been swept away and late last night half of the other side had gone. A further section of the highway at this point has been undermined and may yet collapse if the rain continues. If there is no improvement in conditions the gap may be extended the whole width of the highway; three-quarters has now been washed out. Last nignt. s indications were for a continuance of rain with a clearing-up todax.

In the Taita Gorge, a section of the highway has been swept away by the Hutt River for 40 yards with damage done to a further section, and the likelihood of further collapse. Both these gorge highways are closed to traffic. The Western Hutt Road has a series of slips but constant efforts by workmen under trying conditions have kept this highway open, though in parts it is one-way traffic. The Hutt Valley generally has not suffered to anything like the same extent as in past severe floods. Where the waters swept away the Ngahauranga Gorge road there is a cataract plunging down into the gap created like a roaring waterfall. The main weir taking the water to the sea alongside the meat works is being hard tested with a pounding of millions of gallons of swift waters, hour after hour. The works staff were busy late yesterday making sandbag barricades to keep the overflow from flooding the works and last night were still watching anxiously. One effect of the discharge of flood waters into the harbour has been to make a large part of Port Nicholson a muddy-coloured expanse in contrast to the green seas without. Heavy Orongorongo Fall. The main force of the rainfall was not felt in Wellington itself. At Orongorongo 10.56 inches had been recorded for 48 hours up to yesterday morning; at Wainui, for the same period, 5.75 and, in contrast, at Karori, 3.84 inches. At Kelburn the official record was 1.75 inches to 9 a.m. Thursday, an additional 2.48 inches to 9 a.m. yesterday, and a further 1.21 inches to 9 p.m. This made 5.44 inches for approximately 60 hours. The washout of the Ngahauranga Gorge Road was caused by a blockage of the underground tunnel through which the water normally flows on its way to the sea. A small landslip fell into the watercourse leading to the tunnel diverting the water on to the highway. There it. washed over the bank at a point where the road has been built up on spoil and rotten rock filling. As the rain continued the flow of water over the highway assumed violent proportions and a menacing roar. The footpath on the north side was the first to give, alongside a deep gully. The gap made, the water made quick work of the road filling and scoured it away like so much mud in the pathway of a great hosepipe With terrific pressure behind it. At least the giving of the highway at this point resulted m the water rejoining its natural outlet and prevented its further destructive flow further down. Great Uneven Crater. The scene at this point was like a great uneven crater, filled with boulders, rock and soil, concrete slabs and the highway fence and posts. Into the crater there flowed the water, swishing over the uneven surface and turning the normal stream into a raging torrent. In the path of the water dozens of the ornamental shrubs which were planted in the raised portion separating the highway for one-way traffic were torn from their bed, and further down past the cut-out the soil of the centre raised portion was cleaned out to a depth of IS inches. It will probably take several weeks to restore the highway to its normal condition, for not only is the road to be filled in to its proper level but also other work will be necessary to prevent a repetition of yesterday’s damage. The depth of the crater made by the water is at least 30 feet. It is on the long grade, less than half a mile past the junction to the bacon works. It appears likely that if the open watercourse leading to the tunnel through the hillside had been piped in the first place the damage would have been prevented, as the slip from the hill face would have fallen on such a pipe and not, as was the case, into an open waterway. For the time being traffic must resort. to the routes used when the gorge road was under construction; via the Ngaio or Khandallah detours. Rapid Scouring. The scouring out of the road in the 'Taita Gorge was rapid. In a few hours from 11 a.m. yesterday a 40-yard Stretch, midway between the Stokes Valley and Silverstream ends, went down* leaving a deep incline 20 feet down into the flooded river, which was continuing to scour away the bank. Three six-feet sections of underground pipe carrying gorge hill floodwater below the road and into the river, went one by one as the road was swallowed up by the river. Telegraph linesmen had a hard task in a high wind and blinding rain as they transferred the lines from a marooned pole inland. 'this road, between Stokes Valley and Silverstream, will now be closed to traffic till further notice and any attempt to negotiate the small lane left for traffic last night will be dangerous as it is being seriously undermined. No residences are affected as there is only one house beyond the washout in this section of the gorge and it can be reached by the Western Hutt Road and a short drive back from the new Silverstream bridge. The Taita Gorge section of I lie high, way lias always been a sufferer during heavy rain and Hood conditions. Western Hutt Highway.

Tbc new Western Hutt main highway stood up well. ’There were nnnicrous slips, many minor and a few serious, but the road was kept, clear, though restricted to one-way passing in parts. At the south end of the Silverslream bridge a bole was scoured right through al the junction of the bridge with the approach. Compared with previous occasions of this nature the farmlands, golf courses and residential sections of the Hutt Valley escaped lightly. There were some small lakes on both the Hutt ami Manor Park links but tin- flooding was mu. extensive. Paddocks and other large open areas were in much the same position. As a contrast only Hie clubhouse of the Manor Park course was

above water on December 11, 1939. What has now occurred indicates that the work of river control is becoming more effective year by y ear. Streets in Petone and Lower Hutt had in many parts the usual accumulations of water at corners and road junctions and in some few streets for almost their full length on one or other side but there was no interference with either traffic or pedestrians beyond minor inconvenience. Some streets on the west side of Cuba Street, Petone, suffered the worst. Elsewhere in Petone the position was good considering the circumstances. Main Road Lake.

A section of the main Hutt Road neag the quarry, two to three miles from Ngahauranga, was under water on the hill side for two hours late yesterday afternoon. Water rushed down through an opening above the quarry gap, which extends in some distance from the road, and sweeping across and down soon covered an area of a quarter of a mile of one side of the road, the central barrier forming a miniature stopbank. Traffic was diverted at this point into the one-way section to the setr side from late afternoon, though the water soon cleared away. In other parts of the Hutt Road motorists ran the gauntlet frequently of flooded stretches which swirled up, and, at cruising speed, hit the underparts of cars with a thud, there were minor slips at intervals. With most previous rainstorms there have been stormy harbour conditions, but this was not the case yesterday, and traffic did not have to contend with spume and spray. On the foreshore at Petone there was a beachlength, uninterrupted litter of driftwood and brush, a ready source of winter firewood supply for those who cared to gather it. A few Imuses on the Esplanade were threatened by the inroads of water from flooded gutters, which overflowed across the footpath. Many Small Slips. The Akatarawa Gorge Road was closed to traffic for a few hours yesterday because of small slips, but it was made fit again for use in short time. There were small slips on the Haywards Road. On the coastal road between Plimmerton and Paekakariki Sludge and small stones were frequent. This applied to most roads along cliffs or hillsides. The city engineer, Wellington, Mr. K. E. Luke, said yesterday that Wellington had been fortunate this time. The only slip of consequence occurred early that morning on Queen’s Drive where 200 yards of rotten rock fell at a point near the Houghton Bay Road junction. A. bulldozer soon made way for traffic. In The City. In Wellington city itself and the suburbs the conditions were most unpleasant, rain sweeping the streets almost without cessation in the period that they are most used. Tramcars were crowded throughout the day. The previous two days’ rain had kept many shoppers from the city but they appeared io brave the conditions yesterday and the streets' had a comparatively normal shopping day and .night appearance. One of the difficulties was the negotiation of footpaths by people using umbrellas. When parties thins armed against the weather met when moving in opposite directions some skill and umbrella manipulation was needed to make a safe passing. There was a further heavy cut-out in the affected part of Ngahauranga Gorge late last night. Here the road has collapsed a further ten feet or so, makim: it probable taht by morning there will be a complete gap in the highway. Railway Services. Railway services in the Wellington province were not seriously affected during yesterday, though the traffic department received frequent calls and repair gangs were constantly on the job. As the result of two small slips on the incline on the Wairarapa side of the Rimutakas between Cross Creek and the Summit, passengers on the Wairarapa express Which left Woodville at 12.30 p.m. were transferred at Featherston to motor-buses, in which they completed the journey to Wellington. Actually the slips were not serious, and the rail-car which left Wellington at 3.30 p.m. for Woodville was able to get: through, but the transfer of the passengers in (he Wairarapa express to motor-buses was deemed advisable to avoid undue delay. As a result of one of the tracks on the Main Trunk lino being affected by slips near Ngahauranga, all traffic had to be diverted over one line. This caused some delay. The New Plymouth train was about an hour late in reaching Wellington, and last night's Limited express to Auckland was running about an hour and a half behind schedule.