THREAT FROM THE ASHLEY

Press, Volume LXXVII, Issue 23299, 8 April 1941, Page 8

THREAT FROM THE ASHLEY

♦ RECENT FLOODS CAUSE CONCERN

EMERGENCY WORK ON NEW STOP-BANK Two lorries and a bulldozer, adapted as a carry-all scraper, are working at full pressure all day long in the construction of a new stop-bank along the edge of the Ashley river, where recently huge floods broke through the old bank and seriously threatened wide, stretches of the country below. Considering the demand as an emergency, the Waimakariri River Trust lent its plant—the bulldozer and the lorries—to the Ashley River Trust, so that the work could be completed as soon as possible, for there is some fear that another flood, coming before adequate new protection could be provided, might sweep down round a point of higher country, flow into the Oust Main Drain and badly flood the country through which the Main Drain flows. The Main Drain has itself given the trust considerable worry through scouring and the depositing of shingle on its lower reaches. Members of the trust, inspecting the work on the Ashley river-bank yesterday, saw the bulldozer and the lorries hard at work building a high bank where the Ashley had earlier washed completely away many chains of the old bank. The Ashley on that occasion rose at an alarming fate, but a later investigation of the rainfall in its watershed and the tributaries, showed why. In fcur days, from March 17 to March 20, there was a fall of 23in in Lees Valley; in that area there was a fall of 10 m in one day. In the Okuku Valley, feeding direct into the Ashley at a point opposite where the river broke through the bank, the fall in the same period was 13in. and Sin fell in one day. In the Ashlev- Gorge the fall was 12m, and St Oxford. 9in. The river had to carry, in a few days, a huge quantity of water. Unless a sudden flood occurs within the next week or so, this new threat to a big expanse of valuable country will be removed by the prompt action of the two controlling authorities and by their quick co-ope-ration in an emergency. Linked with the control of the Ashley and the Main Drain through the Oust area, are the stens being taken by the Waimakariri River Trust to prevent the frequent flooding that has occurred in the 700 acres of good farming land about and Flaxton, where the Cam river has for many years caused flooding by backing up when the Waimakariri floods, blocking the natural land artificial drainage of this area, and flooding a great deal of it. The trust has installed a system of control gates at field and road drains which enter into the Cam and these are already proving their effectiveness in preventing backing-up. As well, the trust has constructed all along the Cam extensive stop-banks, right in to Kaiapoi. These will soon be completed and will keep the river in check considerably in an area that has given trouble for many years. Work at Kalapol More important still, perhaps, is the work being done on the Cam just below the Kaiapoi township. There the Cam has become swollen by the water of the Main Drain and the old south channel, where considerable seepage will always occur. The Cam useif, in its tufn. enters lower down into the Waimakariri. When the big river floods, particularly at high tide, the Cam watersjDack up and flooding occurs on the low-lying ground for hundreds of acres above Kaiapoi. Two huge dragline excavators are now working on the' banks of the Lam just below the Kaiapoi township, building them up from sludge dragged from the river, widening the riverbed and improving greatly the channel and its. ability to deal with .flood water. Where one of the old channels flows into the Cam, below the site where the dragline excavators are working, floodgates will be erected well up this stream to facilitate control. Yesterday. at high water, there was such a depth of water in this channel that members of the trust were able to sail a good way up it in a launch, right to the, site of the projected gates. These will be constructed on dry land, to facilitate that work, and the water diverted from higher up, down a Sl Thf net’tanks being constructed just below Kaiapoi will be 7ft above high-water mark and such has been the flow of floods measured by .the trust' that this height is fully required for adequate flood control. The work, as well, will considerably improve the appearance of the stretch of water below the township. Another less important. but' still necessary work in this part of the trust’s programme is improvement .to the bed of the Main Drain itself in the Cusl area, where a bulldozer will be used to remove aggradations of shingle.