NEW WAIPU ROUTE

New Zealand Herald, Volume LXXV, Issue 23010, 11 April 1938, Page 8

NEW WAIPU ROUTE

[ ATTRACTIVE DEVIATION |- ; SAVING OF SEVEN MILES |L _ j! VARIED SCENIC TERRITORY It"' ROAD AVAILABLE NEXT MONTH |i Notable among State road construc--1 tion works of recent years, the at--1 tractive deviation on the main highway > to North Auckland between Kaiwaka and Waipu is expected to be ready for [ ' use at the 'end of May. Following almost a direct lino ior slightly over : nine miles through hills never previously served by road, the new rout© will save approximately seven miles in the present distance of 115 miles from t- Auckland 'to Whangarei. Moreover, easv top-gear grades will reduce travelling time by perhaps half an hour, although it may bo two years before " the road surface is paved. Some fine scenic country will be opened on this new road. Within the first mile the road passes around the base of a'bush-clad mountain, and other beautiful bush grows in many of the deep valleys and along hillsides where the road has been built. From the southern end there is a gradual climb ,to the crest of Pilbrow Hill, three and a-half miles from the northern junction, and from this point on a clear day a magnificent view is obtained of the Whangarei Harbour on the East Coast and the Kaipara Harbour on the West Coast. Circuitous Route Abandoned Actually 15J miles of new road will eventually be- provided from Topuni to the northern extremity of the Waipu Gorge, where the deviation rejoins the present highway. The circuitous 22-mile -route round through Maungaturoto, which now forms the apex of a triangle, will no longer be necessary. Many kinks will be avoided in the road near Kaiwaka, where a quarter of a mile will be saved in two miles, and there will be do more manoeuvring round the 77 corners in tive miles of the gorge. In order to eliminate the tortuous subway and overhead in existence between Topuni and Kaiwaka, the new roar"! will follow the eastern side of the railway from Topuni over several farmers' fields before proceeding into the hills beyond Kaiwaka. Work iis at present being completed in stages along 11 miles of the deviation north of Kaiwaka. More labour is now being engaged than at any other time, there beine; some 200 men under the public works overseer, Mr. A. J. Colebourne, who has been in charge of the job since it began 18 months ago. It may be twice this time before the ' whole route from Topuni is open. Working Methods Contrasted

Bullock teams did their share in the early days of the deviation," and as many as 85 horses have been in harness. Seventy are still used, chiefly to haul scoops, but gradually they are being dispensed "with. In strong contrast to such methods are those now followed as the result of using heavy machinery on the job. This includes an excavator and two power shovels, a and two rollers, two crushers and two air compressors. At two points it was found necessary •to divert streams. In the first instance, new banks were cut for the winding Kaiwaka Stream to save expenditure on two bridges that would otherwise have been necessary over deep gullies which have been filled in. Some distance further on the Piroa Stream was diverted out from the foothills to prevent possible washouts and to give greater- stability to the road where it has been cut out from the hillside. One of the five double-width concrete bridges along the deviation has just been completed over the Piroa Stream. , Features of Engineering

Engineering problems really began on "the hill beyond the Piroa Stream for a distance of one mile to the top of Pilbrow Hill. The width of the road was reduced from 24ft. to 20ft. over this section, and an average of 1200 cubic yards,of earth to the chain was scoured out of: the hillside. "Usually spoil had to bo carted only short distances of up to four chains. It was into gullies between spurs, the deepest, situated about half-way up the incline, being about 60ft. Approaching the hilltop the road present? a host of surprises within a distance of a few chains. It falls away into the deepest unfilled gully of 150 ft., covered in lovely bush, with a fair representation of kauri trees, some of which are large. The road sweeps round a two and a-half chain radius corner, the sharpest turn encountered over the entire route, and then culminates in the longest cutting of 70ft., from which 20,000 cubic yards of material was removed. At this- time also the grade is at its steepest of Ift. in 13_ft. Then at the brow of the hill a wide panorama of picturesque beauty is unfolded. Future Dargaville Road Thereabouts at present the road i* particularly narrow. The section is known as the 'No. 1 quarry, and it will be widened later as rock is removed to build up the running surface. Virtually metalling is all that is required before the road is made available to traffic. Fj-om the top of Pillbrow Hill there is an easy grade of Ift. in lift. for three and a-half miles down to the Waipu junction on the main highway. Several fairlv formidable cuttings are passed, completing an altogether pleasing new drive. A little over three miles from the v Kaiwaka end of the deviation is the turn-off on what will eventually be the main route to Dargaville via Maungaturoto. Work on this highway is as far advanced as that on th© main devi-* ation.