HOW BIG IS THE CLUTHA?

Otago Daily Times, Issue 26996, 3 February 1949, Page 4

HOW BIG IS THE CLUTHA?

Inquiry By Daily Times Where does the Clutha (or Molyneux) River rank among the great rivers of the world? This is a question that has been asked of the Daily Times on very many occasions, over a great number of years, and has been' answered with more or less satisfaction to readers—sometimes less rather than more, when figures supplied from official sources have been vigorously challenged by correspondents.

• In the hope of obtaining an authoritative statement upon the position of the Clutha in relation to other big rivers, the Daily Times recently submitted the. question to the Research Service of the Encyclopaedia Britannica. The findings of the Research Service were checked by an expert in the School of Geography at Cambridge, and the reply is: “I am afraid that the figures for the size and rate of flow of the main rivers of the world do not bear out the local opinion of the Clutha. Its rate of discharge is estimated at 1,100,000 cubic feet per minute (which corresponds with your figure) or 4 cubic miles per annum, and although this is relatively large for its short total length of 210 miles, it cannot, by the nature of things, compete with the major rivers with tropical rainfalls. The table below shows most of the world’s principal rivers

Clutha and that of very much larger rivers in other countries. “The amount of discharge of a river depends on a number of factors,” Mr Greenwood said, “ including the size of its catchment basin, the amount of rainfall, snowfall and evaporation in the various parts of the catchment basin, the gradient of the various reaches of the river, v the amount of water lost by seepage, and so on, and it will be. evident when -considering these factors relative to the Clutha that its discharge cannot possibly approach that of very many great river systems in other lands. “ So much for the facts of the case, he added “I do not, .however, feel that we need feel particularly disappointed about it! Mere size is not always a criterion of value or beauty and the Clutha flows amid particularly fine scenery and its waters provide the means for much needed irrigation

This statement was submitted by the Daily Times to the Department of Geography in the University of Otago, and Mr R. H. Greenwood, M.A. (Canterbury), F.R.G.S., of that department observed that while different authori-. ties quote somewhat varying figures for the volume of discharge of the world’s rivers into the sea, those quoted' above indicated the correct relationships between the discharge of the

in Central Otago and the potential for future hydro-electric schemes. “ Periodically, we lament serious flooding in the Lower Clutha Valley, but here again the volume of flooawater and the extent and nature of the damage is very limited compared with the ravages .caused by such rivers as the Mississippi, Hoang Ho and Yangtse. And for this. too. we may be thankful!”

The following table shows most of the world’s principal rivers." River Area of Length Annual rain Mean anbasin (sq. (miles) fall of basin nual dismiles) (cb. miles) charge (cb. miles) Amazon 2,230.000 4000 2834 528 Congo 1,540,000 2600 1213 419 Nile 1,290,000 3700 892 24 Mississippi .. .. 1,290,000 4100 . 673 126 La Plata 995,000 2300 905 189 Yangtse Kiang 689,000 32001 409 125 Volga 592,000 2200 152 44 Ganges/Erahmaputra 588,000 1800 549 43 St. Lawrence .. .. 565,000 2400 339 87 Hoang Ho 387,000 2500 118 .29 Indus 360.000 1900 104 26 Danube • - .... 320,000 1700 199 67 Irrawaddy •.. .-. 158,000 . 1300 ? :. . * Rhine 75,000 850 — —'... Clutha — 210 — 4