A Romance of Lake Wakatipu
Note 15.—Clutha River
Note 15.—Clutha River.
This is par excellence the river of New Zealand. It is named after the River Clyde. The difference in articulation is due to the fact that the Highland instead of the Lowland pronunciation has been adopted. Strange as it may seem, the Clutha could supply thirty rivers like the Clyde and still have water in abundance to spare. This will appear from the fact that, whereas the latter discharges 48,000 cubic feet per minute, the discharge from the Clutha is 1,674,000 cubic feet. In the year 1867 the late Mr. J. T. Thomson, then Chief Surveyor, estimated the discharge as low as 275,565 cubic feet. That estimate was made at a time when he river was low; still, it is impossible to reconcile it with page 114other measurements. Mr. Balfour, late Marine Engineer, whose observations were made about the same period, sets it down at 1,690,000 cubic feet. Subsequent inquiries prove these figures very nearly correct. The Inspecting Engineer, Mr. Gordon, gives the following as approximates: Minimum discharge, 837,000 cubic feet; maximum, 5,040,000 cubic feet; average, 1,674,000 cubic feet. The drainage-area comprised within the alpine regions beyond the junction of the Kawarau covers 8,000 square miles. These western latitudes are subject to a much heavier rainfall than those situated more easterly. That is explainable in the fact that the dividing-range and its offshoots, comprising the Southern Alps, are in the direct course of westerly weather, and its rain-clouds, depressed by overloads of moisture, get caught in the mountains. In that way their flood-gates are opened and the surcharges allowed to escape before they reach the easterly side. In token of that theory, which we may say is otherwise well authenticated, the rainfall registered at Hokitika, on the west coast, stood in the proportion of 120in. to 24in. registered for the same period at Christchurch, on the east coast. A reference to the chart will show these two places are situated almost parallel to each other at opposite sides of the island.
The position of the Clutha in relation to other great snow-rivers of the world will appear from the following: The Irawaddy, in Asia, has a minimum discharge per second of 84,000 cubic feet; maximum, 1,000,000 cubic feet; average, 350,000 cubic feet; its flood-discharge for 1877 amounted to a total of 466,120,288,940 meter-tons of 37 cubic feet; its catchment-basin is 158,000 square miles, and its length 900 miles. Brahmaputra: Minimum discharge, 146,000 cubic feet; maximum, 1,800,000 cubic feet; average, 520,000 cubic feet. The River Nile, at Assouan: Minimum, 24,000 cubic feet; maximum, 362,000 cubic feet; average, 101,000 cubic feet. River Ganges, 36,000, 494,000, and 141,000 cubic feet respectively.
The relation in which the Clutha stands to the other river-systems of the world will be made apparent by the following: The Missouri is 2,908 miles, with a drainage-area of 518,000 square miles. Its annual discharge is estimated at 3 78/100 billions—i.e., 3,780,000,000,000 cubic feet. Its mean discharge per second is 120,000 cubic feet. The elevation above sea-level ranges from 381ft. to 6,800ft. The Upper Mississippi, 1,330 miles, has a drainage-area of 169,000 square miles, and an annual discharge of 3 3⁄10 billions, or, per second, 105,000 cubic feet. Its elevation is from 381ft. to 1,680ft. The Ohio, 1,265 miles, has an area of 214,000 square miles; annual discharge, 5 billions, or, mean per second, 158,000 cubic feet; elevation, 275ft. to 1,649ft. Arkansas, 1,514 miles; area, 189,000 square miles; annual discharge, 2 billions, or, mean per second, 63,000 cubic feet; elevation, 162ft. to 10,000ft. Red River, 1,200 miles; area, 97,000 square miles; annual discharge, 1 8⁄10 billions, or, mean per second, 57,000 cubic feet; elevation, 54ft. to 2,450ft. Lower Mississippi, 1,286 miles; area, 1,244,000 square miles; annual discharge, 21 3⁄10 billions, or, mean per second, 675,000 cubic feet. The Danube, 1,722 miles, with a drainage-area of 234,000 square miles, has, at extreme low water, a current of 70,000 cubic feet per second; at ordinary low water, 125,000; at ordinary high water, 324,000; and during extraordinary floods averages 1,000,000 cubic feet. Its general average, based on observations made during a period of ten years, is set down at 207,000 cubic feet per second. The French river Loire, with a length of 626 miles, and a drainage-area of 44,979 square miles, has a maximum discharge of 353,000 cubic feet and a minimum of 10,600 cubic feet per second. It is described as a river having all the irregularities of the mountain-torrent. La Plata, in South America, has a length of 200 miles, with a drainage-area of 1,600,000 square miles, and a discharge of 52,000,000 cubic feet per minute. Its waters are easily recognisable sixty miles out to sea.
The discharge of water from the lakes into the three Clutha river-sources averages 1,554,000 cubic feet per minute, which leaves 120,000 cubic feet picked up from its tributary streams en route to the sea, so that, even although the flood-gates alluded to in Note 16 proved successful, the river would still have a water-supply equal to that amount. That would be a very small stream to contend with compared with the present volume, and would page 115lay bare the river-banks to a depth of many feet, which have never been seen by the miner. Once reduced to these limits and we have no doubt the miner would find a way to get quit of the remainder so as not to be baffled in his endeavours for getting down to the bed-rock.
About the middle of the sixth decade of the present century, the Clutha being then at the lowest level to which it is known to have attained, the Chief Surveyor of the district registered the outfall at 275,865 cubic feet, which he sets down as a motive-power equal to 422,500-horse power nominal. This must have been just about the time Hartley and Riley made their wonderful discoveries at the Dunstan. The fall in the river from its inset at Lake Wanaka averages 10ft. per mile, which gives a through-length fall of 2,000ft. at the mouth. Its drainage-area—8,000 square miles—is exactly 2,838 miles in excess of the drainage-area of the Thames (England).
Mr. James McKerrow, formerly District Surveyor of Otago, whose early explorations and, considering the state of the country in these days, astonishingly-correct observations did far more towards settling the country and developing its resources than those of any other man, makes the following pertinent remarks regarding the economics of these inland water systems: "The lakes are a very great feature in the natural history of the country, and perform a most important function in its economy. They act as regulating reservoirs to the mountain-torrents emerging from them, for over their broad surface the floods find room to spread their volume until there be time given for the accumulation to pass away in the steady flow of one river. The value of the lakes as a means of restraining such rivers as the Clutha within safe limits will more readily appear when it is considered that the Wakatipu alone covers 114 square miles, the Wanaka 75 square miles, and the Hawea 48 square miles—altogether 237 square miles of lake to regulate its volume. These lakes have also a rise and fall of several feet. From the data thus given it will be evident that but for the tempering influences of the lakes, the Clutha, in place of flowing along a well-defined channel, a perennial stream, would devastate the whole country."
After nearly thirty years' European experience, the soundness of this theory, put forward at a time when the interior was terra incognita, can be fully attested. With the exception of a few miles of low-lying country at its mouth the Clutha has never been known to overflow its banks. With a body of water like this well confined, the bed in some instances has been scooped out to a great depth, the banks alone in these cases giving a drop of from 50ft. to 60ft. The country through which it flows is widely diversified in its aspects, varying from alluvial flats of great extent to abrupt mountain-gorges, in which barely sufficient room exists for road-making. Through some of its rocky defiles the river runs with great velocity. The average current, however, does not exceed four knots. In appearance these defiles are, as a rule, wildly grand. They form so many necks or funnels in the body of the river, at which the channel gets so contracted that the current receives all the greater impetus. The rush is for the most part that of a smooth volume, without any sign of submerged rocks or boulders. It does not demand great powers of imagination to invest these defiles with a handful of satanic lore and describe them as the devil's mill-streams, although it must be confessed the hydraulics are not generally recognised branches in demonology. The scene overhead is equally wild and suggestive. The precipices are high, the gorges in that way getting completely walled in. These precipices exhibit rocks and boulders striking all manner of threatening attitudes, from the slight list forward to the distinctly dangerous-looking, overhanging ledge. Some of these mighty excrescences look like turrets, embattlements, and hill-forts, but they are all too great, too magnificent, to be associated with the warlike operations of man. If we are to do them substantial justice we must bring the imaginative powers again into requisition and people them with a race of giants, armed to the teeth with the artilleries of heaven. That is the only way oat of the difficulty, and even then we may congratulate ourselves upon having escaped lightly.
Incidental allusion has been made to the alluvial flats. For the most part these have now attained a high state of cultivation. Although cereals are the page 116staple crops, a higher class of husbandry has been introduced. The vine, and orchards of apples, peaches, apricots, plums, and the smaller fruits are cultivated with great success from the Lakes to the sea. The soil, composed of the detritus of mica schist, lime, and the silt of the river, is exceedingly fertile. In some of the drier and more gravelly soils fertility has been greatly stimulated by irrigation, as at Dunstan Flat, where a Frenchman for many years cultivated an extensive orchard, and from the produce thereof manufactured what was acknowledged to be an excellent light wine. At Roxburgh, lower down the valley of the Clutha, fruit-growing has long been successfully established, and is the principal source of supply of the Dunedin market. A line of railway to connect Lake Wanaka with the Otago through-line is in hand, and will tap the Dunstan en route. Meantime, it is a route largely patronised by the tourist traffic, the Dunstan being the alternative trip for visitors going to or returning from the Lakes.
For navigable purposes the river has been of small account. In olden times, prior to the period of European occupation, the North Island Natives made certain memorable warlike raids upon the southerners by this route. Fuller particulars of this primitive description of navigation will be found on reference to Note 17. Shipping, of the schooner class, did, and now and again still do, visit the low reaches; but it never was an extensive trade. In furtherance of the enterprise which has all along distinguished Otago, an effort was made in 1861 to establish a trade on the Clutha. On the 11th September of that year the Dunedin Harbourmaster reports that he had examined the river, and that it could be navigated a distance of forty miles from its entrance. Early next year a contract was entered into for the erection of a light-draught stern-wheel steamer to ply between Port Molyneux and the mouth of the Tuapeka. The craft was duly launched and put into commission, a subsidy of £150 per month being provided. It never was a successful venture, and has long since been abandoned. A subsequent attempt made to renew the enterprise likewise failed, and now that the railway system has been brought into operation the river traffic is confined to an occasional visit of a stern-wheel steamer calling at Tuapeka Mouth and other points to bring down wool, grain, and produce to the railway at Balclutha, or, in some cases, on by sea to Dunedin.