DOMINION RAINFALL

Waikato Times, Volume 107, Issue 17995, 14 April 1930, Page 13

DOMINION RAINFALL

GOVERNMENT SURVEY. BENEFIT TO PASTURE. British farmers and other visitors have recently expressed astonishment at the richness of New Zealand's pastures. This richness is concisely explained by'the Government meteorologist, Dr. Kidson, in the following words: — “The Dominion is very fortunate In that, in spite of the fact that the rainfall is, in places, very heavy, and the general average is high, the number of rain day's is practically nowhere excessive. In this respect it compares very favourably with the British Isles. When, in addition', it is remembered that the average amount of cloud is only moderate, that the air is well washed by rain, and little polluted by smoke, and that sunshine is abundant, the reason for the richness of New Zealand pastures can he easily understood.’,’ Dr. Kidson’s remarks are published in “The Average Rainfall in New Zealand for the period 1891 to 1925," a bulletin which is intended to accompany a “rainfall map’’ of the Dominion. This also has been prepared by Dr Kidson, and it will be of great importance to tbe farmers. The map will supplant those rough and ready, and often inaccurate diagrams of the country’s rainfall which figure In school text books and elsewhere. It is in advance of anything as yet undertaken in Australia. *

“Patches” of High Rainfall. The fact that impresses one most is the high average rainfall experienced by New Zealand, remarks Dr. KidsanAs regards occupied areas, this is particularly the case in the North Island. If there is any area at all in that Island which experiences a smaller rainfall than 30 inches, it is of negligible extent. There are quite a number of patches of high country which receive more than 100 inches. The farthest north of such areas is in the western part of the North Auckland Peninsula. Smaller areas are found south-east of Tauranga, and on the Tawairoa Range, west of Te Kuiti. The peninsula extending between the Bay of Plenty and Hawke’s Bay to the north-east at East Cape is one with a generally heavy rainfall, where, again there is a considerable area having over 100 inches, including a patch to the northeast of Wairoa. The remaining areas in the North Island are around Mount Egmont and in the Tararua and. Rimutaka Ranges. The heaviest rainfall hitherto recorded in New Zealand is that at the Mountain House at Mount Egmont, where over 300 inches in one year Is not unusual . . . Dry Areas. 8,3 fL r ! Instances of “rain shadow's” are found in several places. Perhaps the most remarkable Is that extending Inland from Gisborne, which is sheltered by ranges on all sides except the east and south east. The country to the north-east of Lake Taupo, also, is a relatively sheltered and dry area. This is of some oonsequence, owing to the porous nature of some of the soils which reduces the availability of (he rain for the production of vegetation. The large and important region extending inland from the Taranaki Bight, and including the Manawatu and Rangitiki counties, is protected by the Egmont and Tongariro massifs to the north-west, the high country of the South Island to the south-west, and the Tararuas and Ruahines to the cast. Another important rain shadow area lies in the eastern districts south from Napier. The driest portion is that around Napier and extending inland to Hastings and Waipuburau, but a relatively dry strip continues right down the Wairarapa to the sea. The North Island is, on the whole, however, remarkably well watered. In the South Island the rainfall distribution is more varied. The_wettest region is that running down the western side of the main range from northern to southern extremities. It is likely that a fall of 200 is greatly exceeded at a few places ontv in this zone, though the .area receiving 200 is considerable. The driest country in the Dominion is found in the inland basins of the South Island, such as the Mackenzie Country and Central Otago. In the latter there Is a considerable area which receives less than 15in per annum, and in parts of the Alexandra and Galloway districts 13in or slightly less is all that Is recorded. Rainfall in the Cities. How the various centres fare oan be gleaned from the map. Wellington's average is from 40in to sSin of rain a year, the figures varying according to the part of the district- “Days with rain,’’ that is days on which more than half a point of rain falls, number on the average 150-175 eaoh year. Auckland has from 175 to 200 days with rain, and an average fall of 45 or more. New Plymouth has the same average as Auckland as regards ■days with rain, but an average fall of 60in. Napier, Nelson and Christchurch come under the oategory of places with rain days per year numbering 100 to 125. Napier has an average annual fall of about 351n\ Nelson 36-40, and Christchurch only 25in. Dunedin’s rain days number 150 to 175, the annual fall being 30in to 40in. Invercargill’s annual fall is 45in. The West Coast, A map in the bulletin indicates the position of the recording stations. The total number is about 850, roughly 450 being in the North Island and 400 in the South Island. The areas in which more stations are most-need-ed are the centre of the North Island, the central mountainous portion of the northern half of the South Island, and. the west coast of the South Island. “It is most regrettable,’’ comments Dr. Kidson, “that more information is not available from the lastmentioned area- For engineers, particularly, it would be very valuable. One is forced to the conclusion that one of the principal reasons for this lack of data from the West Coast is the reluctance of some of the inhabitants to publish figures showing a f high rainfall, which they fear will 3 give their' district the reputation of having a bad climate. This attitude is ’ very much lo‘be deprecated. Nothing ) is to be gained by the suppression of ■ truth. On the contrary. Ihe facts , arc probably morn favourable than is - believed by residents in olher parts > of ihe country.”