Geology of the Provinces of Canterbury and Westland, New Zealand : a report comprising the results of official explorations
Glaciers, Rivers, and Lakes
Glaciers, Rivers, and Lakes.
Owing to the intimate connection in which, with the exception of a few minor streams, the glaciers, rivers, and lakes stand with each other, I have thought it most convenient to treat of them together, in order to avoid repetition. Measured with Amsler's planometer on the map of the Province of Canterbury, published before the secession of Westland, by authority of the Provincial Government, in September, 1866, on a scale of 10 miles to 1 inch, the area of both provinces is 17,963 square miles; there are, consequently 62 miles less than the amount given in later official records, which is:—For Canterbury, 13,583 miles, and Westland, 4442 miles; total, 18,025 miles.
Calculating the hydrographic basins on both slopes, those on the eastern side amount only to 13,353 square miles, whilst those on the western side reach 4610 square miles, which is caused by the fact, that some sources of the western river systems stretch across the boundary line between the two provinces, running along the main divide of the Southern Alps. It will be difficult to find another country with an area of such limited extent as these two provinces, possessing so many important water-courses, of which however none, with the exception of a few tidal rivers, are navigable. Of the hydrographic basins reaching to the main divide, or owing their origin to true glaciers, six are situated on the eastern slopes, namely—the Waitnakariri, Rakaia, Ashburton, Rangitata, Waitaki, and Molyneux; and sixteen on the western slopes—the Taramakau, Arahura, Hokitika, Waitaha, Wanganui, Whataroa, Waiau, Waikukupa, Weheka, Karangarua, Mahitahi, page 194Paringa, Haast, Okura, Waiatoto, and Arawata; the rest, of which the area will be found in the following list, having their sources in the secondary ranges. Of Banks Peninsula, forming an orographical system separated from the rest, I have only given the total area, the drainage being divided into portions too small for calculation by the process mentioned. With the exception of the Waitaki, of which the southern portion lies in Otago, the northern half of the Hurunui system, and a small portion of the Taramakau sources, both situated in Nelson, all the hydrographic basins are comprised within the boundaries of the two provinces. Exception must, however, be taken to the southern sources of the Molyneux, (the largest river in New Zealand), which are situated in this province, by far the greater portion, of its hydrographic system being in Otago.