The Waitaki.

Taking the rivers according to their volume, and the extent of the hydrographic basins they drain, the Waitaki, as previously pointed out, is the most important. The sources of this river rise in those regions of the Southern Alps, which are not only the highest, but where also snow-fields of the largest extent exist, from which a number of huge glaciers descend to lower regions. Amongst them, the great Tasman glacier, the main source of the Waitaki, is the most important, its length being 18 miles, whilst at its terminal face its breadth is still one mile and three-quarters; it is the glacier that reaches lowest in New Zealand on the eastern side of the Alps, as its lower extremity stands only 2456 feet above the level of the sea. For three miles from page 200its terminal face upwards, the outlet of another large glacier flows along its eastern side. This second, the Murchison glacier, lies in a valley one mile and a quarter broad, but it does not reach the Tasman glacier, its terminal face being situated two miles from it; and we may attribute the fact that it melts before reaching the other, to the circumstance that it is more exposed to the sun, and is not like the Tasman glacier, entirely covered with enormous moraines in its lower portion. The outlet from the Murchison glacier, after flowing for several miles along the eastern side of the great Tasman glacier, was, in 1862, when I discovered them, joined by the outlet of the latter, issuing from a glacier cave on its eastern edge. On my second visit, in 1870, I found that the Tasman river now issued from two glacier caves, of which one was in the old spot, whilst a second one had been formed in the centre of the terminal face. The united outlet forms at once a large torrent, always of a dirty yellow colour, thick with suspended matter, appearing to me to have about the same quantity of water as the Waimakariri has in the Canterbury plains. After a course of a few miles, it is joined by the Hooker river, the united outlet of the. Hooker and Mueller glaciers, of which the former, eight miles long and one mile broad, having a north and south direction, brings down the ice masses from the southern slopes of Mount Cook, the eastern side of Mount Stokes, and the northern portion of the Moorhouse range. The Mueller glacier, six miles long and one mile broad, has a general south-west and north-east direction, and is fed from the nevé fields of the south-eastern slopes of the Moorhouse, and the western slopes of the Sealy range. After a long continuance of fine weather, this outlet is not so turbid as that of the principal glacier, and can be crossed without difficulty on horseback, and even on foot, although the boulders in its bed are generally large. The united river runs in a straight valley, having a general breadth of three miles for twenty-one miles, or twenty-four miles from the terminal face of the Tasman glacier, before it enters Lake Pukaki, the last five miles forming a delta of a very swampy character, and impassable by man or beast. Higher up, the river runs in a number of shallow channels, anastomosing continually, of which I counted as many as thirty in crossing. Before reaching the lake, a number of smaller tributaries join it from both sides, of which the River Jollie is the most important. Lake Pukaki is nine miles long and four miles broad. It is a fine sheet of water, surrounded by morainic accumulations, forming banks often 250 feet high. Here and there some roches moutonneés appear amongst them, and the former higher level of the lake can easily be traced by the numerous old page 201beaches rising one above the other around its shores. A small rounded island rises in the south-western corner, above the surface of the lake. The water is milky white, even during the most beautiful weather, from fine glacier silt continually brought into the lake in enormous masses. The view from this lake of the Southern Alps is really magnificent, and I have no doubt that in years to come smiling villas will be built here, where lovers of beautiful scenery, and those who seek for health and recreation, will be able to pass delightful days. At the northern end of the lake the river issues again, now running between high banks and generally confined to one channel, bearing the name of Pukaki. After a course of nine miles, the Pukaki joins the Takapo outlet, and the united river bears the name of Waitaki. There is only one ford over the Pukaki river, about six miles below its exit from the lake; it has a long horseshoe form, and leads over big boulders.

If we consider the length of its course, the Godley river, the eastern main source branch of the Waitaki, is the principal one; the same nevé fields which feed the Lyell glacier at the head of the main Rakaia, supplying also the Godley glacier, the principal feeder of the river of the same name. This glacier, which has a length of thirteen miles, is at the junction of the Grey branch, the broadest of the New Zealand glaciers, measuring nearly four miles across, and forming one of the finest oners-de-glace imaginable. On its eastern side, the Fitzgerald glacier nearly reaches it, only a lew hundred yards intervening, its outlet running below the main glacier. The Classen glacier is separated from the terminal face of the Godley glacier by a short distance only, their terminal moraines being separated only thirty or forty yards from each other, thus presenting a nearly uninterrupted terminal face of over three miles. The Classen glacier is about eight miles long and nearly two miles broad, being fed by some of the largest snow-fields in our Alps. After a nearly straight south-by-east course of 22 miles, the united affluents of both glaciers, under the name of the Godley river, reach Lake Takapo. The average breadth of the valley is about two miles, the river, like the Tasman (and, in fact, all our large glacier rivers), meandering in countless channels over it, changing its course with every heavy freshet. The Godley has also formed a very swampy delta at the head of Lake Takapo. Six miles above the junction,, on its eastern bank, the Godley receives the Macaulay, an important tributary, having two glacier sources on the southern slopes of Mount Forbes, no other tributary of any importance joining its course.

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Lake Takapo is fifteen miles long with an average breadth of three miles; it is not only surrounded by morainic accumulations like Lake Pukaki, but owing to the presence of large ranges on both sides, older moraines rising about 1500 feet above its surface, and looking like gigantic terraces, accompany its eastern and western shores. Its waters are also of a milky-white colour, and it possesses several islands situated in about its centre, consisting of a very hard semicrystalline bluish sandstone very much ice-worn. Unlike Lake Pukaki, where we still meet with small remnants of Fagus forest, Lake Takapo, although only 2437 feet above the sea level, lies already above the forest line, only sub-alpine vegetation growing near its banks. The high mean elevation of the country is, without doubt, the cause of this peculiarity. The difference of level of Lake Takapo, between its highest and lowest water mark, is eight feet; the lake has been known to rise four feet in twenty-four hours during heavy rain, but it takes some weeks to fall again to its usual level. Lake Takapo receives another important affluent on its western side, namely, the Cass, the glacier sources of which are situated on the south-eastern and southern declivities of the Liebig range, its course being nearly due north and south, and about 22 miles long. A few miles below the delta of the Cass, another small stream, the outlet of Lake Alexandrina, joins Lake Takapo. The former is a small picturesque lake, partly surrounded by ice-worn rocks, partly by morainic accumulations, and lies 2460 feet above the sea level, or 23 feet above Lake Takapo. It is five miles long, and about half a mile broad, and was, without doubt, formerly a portion of Lake Takapo, from which it was cut off by the large shingle fan of the Cass river. The outlet of Lake Takapo issuing from its southern end is named the Takapo; it runs for a number of miles in a deep channel, where it breaks through the morainic accumulations by which the lake is here walled in; after leaving them it enters the post-pliocene alluvium beds of which the greater portion of the Mackenzie Country is formed, and although still fringed by terraces on both sides, its bed becomes broader and more shallow, fords over it being easily found by an experienced across country rider. After a course of 25 miles, it is joined by the Pukaki river, when, as before mentioned, the united river assumes the name of Waitaki.

Flowing for three miles in a south-south-west direction, it is joined by the Ohau, the outlet of Lake Ohau, which, after issuing from that lake, follows an east-south-east course of a length of page 203thirteen miles. Lake Ohau, ten miles long, and averaging three miles in breadth, is a picturesque sheet of water lying 1837 feet above the sea level. Whilst the Ben Ohau range rises so abruptly from its eastern banks that it is impossible to pass along it on horseback, the mountains on the western side are distant from half a mile to two miles from its western shores, the intervening space being filled with gradually rising morainic accumulations forming terraced grounds reposing against the mountain sides. On both sides small groves of beech forest heighten the charm of the beautiful scenery; moreover, the water of the lake is perfectly clear, forming in calm weather a broad mirror for the serrated mountains along its banks. Here, also, several portions of the lake, which once stood at a higher altitude, have become isolated by the lowering of the waters to their present level, and now form lagoons amongst the morainic accumulations. Lake Ohau is the recipient of the River Hopkins, formed by the junction of the Dobson with the former, five miles above the northern end of the lake. They are both of glacier origin, the Dobson or eastern branch deriving its waters from the south-eastern slopes of the Moorhouse and the south-western slopes of the Sealy range; the Hopkins from the south-western flanks of the Moorhouse range, and the southern slopes of Mount Holmes. The Dobson has a south-by-east course; the Hopkins, a general south course, running south-west for the first, due south for the middle, and south-east for the latter portion. They are both about 24 miles long. In the middle portion, their beds are repeatedly narrowed by huge morainic accumulations, through which they have cut a channel of a gorge-like character, after which they enlarge considerably, and flow over broad shingle-beds. Before reaching their glacier sources, the valleys of both rivers narrow considerably, and assume the character of wild rocky gorges, so that in this respect they resemble most of the valleys in the Swiss and Tyrolese Alps, leading up to the glaciers. Where the Ohau enters the lake, the same extensive swampy delta has been formed as we observe at the head of the two other Mackenzie Country lakes. As pointed out in the first chapter, the valleys of both main branches of the Ohau river possess an additional charm by their lower regions being densely wooded with beech forest. Although their tributaries, even in fine weather, are sometimes very difficult to cross on foot, they have only very short courses.

I have already repeatedly alluded to the peculiar physical features of all our alpine rivers, namely—that they generally possess numerous page 204and well-defined terraces in their upper and middle courses, being simply shelves cut in the solid rock along the mountain sides by a gigantic glacier. These shelves in many instances are situated as high as 3000 feet above the present level of the valleys, and are very characteristic of our alpine scenery, although I may add that the same features are also amply developed in the European Alps, the Himalayas of Asia, and the Rocky Mountains of North America. On ascending the mountains in these valleys, the size and extent of the shelves become still more manifest than when travelling only along the river-bed. The most westerly tributary of the Waitakiis the Ahuriri, the glacier sources of which are situated on the southern slopes of Mount Huxley, the southern continuation of Mount Ward. The valley of the Ahuriri is fifty-two miles long; for twenty-seven miles it has a southerly course, after which it turns gradually to the east, when, for twenty-five miles it runs in that direction, joining the Waitaki fourteen miles below the junction of the Ohau river. The river-bed of the Upper Ahuriri for about eight miles, is narrow and rocky, the mountain slopes on both sides rising abruptly; it then gradually expands, but is still repeatedly crossed by large moraines, through which the river has cut a narrow channel. Fourteen miles from the head of the river, the valley is nearly two miles broad, and is now, for seven miles, one large swamp through which the river sluggishly meanders from side to side. At the lower end of this strange fen, a huge moraine crosses from one side to the other, and it is at once evident to the visitor, that at one time a lake must have existed above it, but which in time was gradually so far filled up, that it has assumed this intermediate instructive stage. There is no doubt that if the present physical conditions now ruling in New Zealand, continue for a length of time, the shingle deposits brought by the Ahuriri into this huge swamp will gradually advance and fill it up entirely, in the same manner as the lakes once lying in the middle courses of some of the northern alpine rivers have been changed into alluvial plains, thus entirely effacing such large remnants of former glacier basins. The Ahuriri, where it issues from the fen, has cut a deep channel through the morainic walls, below which broad alluvial plains stretch from side to side. Here the river flows also in a deep bed with terraces on both sides, which, before the Lindis Pass stream is reached, is confined in a deep rocky channel, the alluvial deposits continuing to fill the valley, and resembling in every respect, those which we meet below the great moraine walls encircling the lakes in the Mackenzie Country plains.

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South of Lake Ohau, the Ahuriri enters into the southern continuation of these plains where, for five of six miles, its bed is of great breadth (in the so-called Ahuriri plains) after which the rocky rangesw approach close to each other again, forming a deep gorge which continues to its junction with the Waitaki. In the fork of the two rivers, Ben More, an isolated range, rises conspicuously, which dur n the Great Glacier Period stood as an island above the ice-masses, and along the eastern and southern base of which the two rivers hare excavated their deep rocky gorges. The Waitaki, below this junction flows for 17 miles, generally confined to one channel, until two miles above the junction of the Hakataramea, the valley opens up the river however, continuing to flow generally in one body, or if drrided into two or more branches, it still has only narrow bed. Nineteen miles below the junction of the Ahuriri, the Hakataramea river joins the Waitaki from the north. It is by far the most important tributary below the former, no other streams of any consequence joining it on the Canterbury side. On the southern or Otago side only small affluents reach it, of which the Otomatakau and Marawhenua are the most important Seventeen miles below the junction of the Hakataramea, the mountams recede on the northern side of the valley, which now opens up still more, the old alluvial deposits on both sides, which hitherto had only been narrow, become wider, the bed of the river itself also gradually enlarges, forming a number of anastomosing branches The further we advance towards the coest, the more characteristic these features become. A series of small terraces are also formed without, however, ever assuming the vast proportion of the terraces in those rivers which have formed the Canterbury plains. The reason of this absence is obvious, the Waitaki glacier, during the Great Glacier period, being of such enormous dimensions that it reached far below the mouth of the Hakataramea, and stood at such a hieh level that the bed of the gigantic river issuing from it, was flowing seven or eight hundred feet above the present valley. Thus the whole valley up to that altitude was covered with alluvial deposits, and although the period during which these beds were formed, is separated from us by a short space of time, geologically speaking, the size of the river was still so enormous that when the glacier after repeated oscillations, at last gradually retreated, it had so effectually destroyed its former bed that only here and there on the summits of the ranges between the Waihao and lower Waitaki, small portions of that alluvium were preserved, so that no [unclear: trraces] of any size could be formed.