WAIRARAPA FLOODS.

Wairarapa Age, 7 April 1931, Page 5

WAIRARAPA FLOODS.

WATERS SUBSIDE IN LOWER VALLEY. WAINGAWA MAKES EXTENDED INROADS. IRRIGATION INTAKE MENACED. The floods which developed, so suddenly in the Lower Valley on Friday afternoon subsided almost as quickly as they had risen. It is clear that they were occasioned by a phenomenal rainfall in the hills —probably something approaching the 231 inches in 24 hours which were recorded at a township in the Nelson district. The rainfall in the open country of the Wairarapa was light. Apart from the spread of flcod waters in the Lower Valley, a good deal of damage was done by the Waingawa to the protected banks in the region of the Upper Plain irrigation intake and the headworks of the Masterton

water-supply. The flood waters from the Waiohine river, which broke its banks in the legion of Matarawa on Friday morning did considerable damage to fences, crops and other farm-land property in the Matarawa district. The flood swept across country and in one instance carried away a field of freshly cut hay, while it is reported that farmers lost a number Of pigs. Practically the vhole of the Lower Valley was clear of flood waters yesterday, with the exception of some low-lying areas adjacent to the Wairarapa Lake. Although it made no such extended invasion of low-lying country as some of the other Wairarapa rivers on Friday, the Waingawa River ran in tremendous volume on that occasion. The deposition of silt and other debris affords evidence that the river rose in places eight feet or more above its normal flow. The damage done to the banks, notably at the intake to the Upper Plain irrigation service, is described by experienced and informed observers as the worst that has occurred over a long term of years. A considerable amount of damage was clone also in the vicinity of the Masterton Borough w;ater-supply intake. In both areas there are highly suggestive indications of the possibility of even more serious damage to follow in future floods.

At the intake to the Upper Plain irrigation service, the Waingawa has cut away the bank to within fifteen feet of the screw-valve which controls the admission of water to the main race. Groynes and other protective works, together with a stretch of bank carrying willows and. other trees went into the flood. The area thus bitten out by tho river was about two hundred feet long and ran to as much as two chains wide. On the same bank, a few hundred yards higher up. a much bigger bite, about two hundred yards long and as much as three chains wide, was taken out of an are? of land owned by the Masterton Borough—the lower part ot the waterworks reserve. The ground thus cut out in a night carried not only willow's but totaras and other trees of substantial size and might beforehand have been regarded as reasonably secure, but the river made very short work of its removal.

In this locality, the river is cutting most dangerously into its bank and strong protective works are imperative ly needed, not merely to protect the irrigation intake, but to prevent serious damage much further afield. Only a comparatively small area of rather sandy land, which presumably might be cut away as easily as some of the territory that went in Friday’s flood, prevents the river from breaking its way into an old channel at present drjv Getting so far, the flood waters would run down the Upper Plain, crossing Dagg’s Road and Kibblewhite Road and reaching the confines of Masterton Borough in the vicinity of the Railway Station. From that point, an invading flood would make its way through the town, by way of Cole Street, Lincoln Road and adjacent areas, to the Waipoua channel. In tho present state of the Waingawa bank in the area indicated, the danger of such a flood invasion cannot be regarded as altogether remote. In the vicinity of the Borough water-supply intake, tho bulk of the river water is running straight in a deep channel parallel with the bank, but rhe latter has been considerably undermined in places and the position of the whole of the works, including those undertaken to provide a supply apart from that of the main race, appears to be decidedly precarious. The continued inroads of the river are manifest in the fact that a protective wall of wired stone which is still under construction has sunk down in places Some other parts of the bank are merely waiting to topple into the channel. A good deal of work has been done of late in laying a double pipe-line and filter bed to carry the water from springs into the borough mains. At the moment no water is I being drawn from the river itself, but it is hoped shortly to open the main race again.