THE MODE OF LAYING OFF GOVERNMENT ROADS IN THE WAIRARAPA DISTRICT.

New Zealand Times, Volume XXXIII, Issue 5427, 19 August 1878, Page 3

THE MODE OF LAYING OFF GOVERNMENT ROADS IN THE WAIRARAPA DISTRICT.

The following is the full textof theletfcer from Mr. J. King, County Engineer of Wairarapa East, addressed to the Chairman of that County Council ai-d to the Chairman of the Masterton Highway Board, which letter was briefly referred to inarcoent issue:—“l begto direct your attention to the system of laying off roads which the Government have adopted within this district. The Government surveyors, who are now laying off roads to the several sections of laud within the blocks which they survey, make no pretension to a knowledge of road engineering ; and as a consequence, the results of their labors, in so far as lines of road are concerned, must be unsatisfactory. In a district like this, consisting mostly .of hilly, undulating land, * the roads cannot be, at tho same time, both straight and level, and in such cases straightness should be always sacrificed to obtain an easy gradient; this is one of the most important principles to be observed in laying off road?,’ especially roads in a new country, which are intended to be permanent highways. * A straight road over an uneven and hilly country may be pronounced bad when merely seen upon the map, for the straightness must have been obtained, either by submitting to sleep slopes in ascending and descending, or else these natural obstacles must have been overcome by a great and unnecessary expense. A good road should wind round hills, not run over them ; and this it may often do without increasing its length." The land surveyor endeavors to obtain long, stright lines, and well-conditioned sections, the longitudinal grade of the road being to him only a secondary consideration. Thus, if the location of road lines be loft to him, we have steep gradients, heavy cuttings, as well as high embankments, and a road most difficult and expensive to keep in repair. Roads laid off to 1 in 8, 1 in 9, and 1 in 10 are not uncommon in this district. To show, therefore, the loss and inconvenience arising from the adoption of these grades, I subjoin figures used by road engineers, from which can be gathered the relative disadvantages as the grade of a load becomes steeper. Presuming that the load which a horse can draw on a level equals 1.00 on a rise of 1 in 100 he can only draw 90. On 1 in 50, only ’Bl ; on 1 in 41, only ’75 ; on 1 in 40, only ’72 ; on 1 in 30, only ;64; on 1 in 26, only *54; on 1 in 24, only *SO ; on 1 in 20, only *4O ; on 1 in 10, only *25. In round numbers, on a slope of 1 in 44, or l*2oft. to the mile, a horse can draw only three-quarters as much as he can draw upon a level; on a slope of 1 in 24, or 220 ft, to the mile, he can draw only half as much. Authorities state that the loss of power on inclinations is even greater than the amounts stated above ; for besides the increase of draught caused by gravity, the power of the horse to overcome it is much diminished upon an ascent. The loss of power being so great on inclination as has been shown, it follows that a road should never ascend or descend a single foot more than is absolutely necessary. If a hill is to bo ascended, the road should nowhere have even the smallest descent, for that would make two hills instead of one ; but it should be so located that it would haveagradual uninterrupted ascent tho whole way,’ As a case in point, I extract the following from * Gillespie on Roads and Railroads.’ ‘ The great Holyhead-road made by Telford through the very mountainous district of North Wales, has 1 in 30 for its maximum, except in two cases (I in 22 and a very short one of 1 in 17), and in them the surface of the road was made peculiarly smooth and and hard, so that no difficulty is felt by loaded vehicles in ascending. On the old line of road, the inclinations had been sometimes as great as 1 in 6, 1 in 7, &c.’ Under the present system of laying off roads in this district, that information cannot be obtained which is most essential in determining upon good and proper road lines. I understand the instructions to assistant surveyors are to the effect that each section shall have a road passing by it, the grades to be estimated, not by careful calculation with the aid of levelling instruments, but simply by the eye. I have it from the best authority that many of the gentlemen now employed in this work have neither the necessary knowledge nor instruments requisite to carry out efficiently so important a work. It is impossible to over-esti-mate the importance of road surveys in the present history of the district, and it is just as impossible to properly locate these roads without first obtaining reliable data from which to work. The first expense will be the least, for I am convinced that the road which has to be made, where merely casual observation has determined the locality, will cost three times what it would have done had the necessary skill pnd precaution been taken. Sir Henry Parnell, in his valuable treatise on roads, gives tho following, which is a case in point. * As an instance amongst others, of the serious injuries which the public sustain by this system of road-making, the road between London and Barnet may be mentioned, on which the total number of perpendicular feet that a horse must now ascend is upward of 1300, although Barnet is only 500 ft. higher than London ; and in going from Barnet to London, a horse must ascend 800 ft., although London is 500 ft. lower than Barnet. Another instance of this defect in road engineering is observable in the line of the old road across the Island of Anglesea, which rose and fell between its extremities, 24 miles apart, a total perpendicular amount of 3540 ft., while a new road laid out by Telford, between the same points, rose and fell only 2257 ; po that 1283 ft. of perpendicular height is now done away with, which every horse passing over the road had previously been obliged to ascend and descend with its load. Tho new road is besides more than two miles shorter. Such is one of the resu-ts of the labors of a skilful road-maker, and many such improvements might be made." Presuming that the surveyor possesses tho necessary qualifications, I apprehend that while engaged in the actual work of land surveying, circumstances do not admit of his making such a thorough examination of the country as will enable him to lay off lines of road to the greatest advantage. His advancement is best secured more by the extent of acreage shown in his returns, and the accuracy of the same, than by the skill he displays in selecting the most suitable road lines. It is therefore unreasonable to expect him to devote the necessary time to that portion of his work for which ho will receive the least credit, and it appears to mo that the work of land surveying under the present system, and the laying off of permanent highways, cannot, unless under exceptional circumstances, be carried on with satisfaction at one and the same time. I have endeavored thus far briefly to indicate what sort of roads we may expect if the present system of locating bo adhered to. I feel assured that many of the roads now being laid off will never be made. At some future time the local governing bodies will have to bear tho expense of re-surveys, tho exchange of land, removing of fences, and in many cases heavy compensation, in order to secure practicable road lines, which will greatly cripple their action in the matter of bridge building, formation, and general improvement. Having briefly hinted at the loss and inconveniences ot the present system, I would recommend the consideration of the following method ; —First, that competent road engineers be employed to locate the road lines, previous to the land surveyors commencing their section work. These road engineers should bo provided by the Survey Department with maps showing the features of the country, the traverses of creeks and rivers, the major and minor triangulation, and such other information as had been obtained. With this information and approximate levels, the engineer could intelligently commence tho work of location, the necessary instructions as to gradients, &c. f being supplied by tho head of tho Public Works Department. Or, in the second place, that a percentage of all Crown lands should bo reserved for roads, such percentage to be at tho disposal of tho local governing bodies for a period at least of 20 years. The local governing bodies would then be in a position to lay off and construct the roads as they became necessary. This latter method I believe to bo the better of the two, because the road engineers would then be able to obtain more reliable information from the Survey Department before commencing their operations. In conclusion, I subjoin a report of the committee of the House of Commons, which has a direct bearing on tho subject in hand. “ By the improvement of our roads, every branch of our agricultural, commercial, and manufacturing industry would bo materially benefited — every article brought to market would be diminished in price, and tho number of horses would bo so much reduced, that by these and other retrenchments tho expense of £5,000,000 sterling would bo annually saved to tho public. Tho expense of repairing roads, and the wear and tear of carriages and horses, ■ would bo essentially diminished ; and thousands of acres, the produce of which is now wasted in feeding unnecessary horses, would bo devoted to tho production of food for man. In short, tho public and private advantages which would result from effecting that great object—the improvement of our highways and turnpike roads—are incalculable ; though, from their being spread over tv wide surface, and available

in many ways, such advantages will not be so apparent as those derived from other sources of improvement of a more restricted and Jes> general nature.*"