RIVER CAUSING TROUBLE

Timaru Herald, Volume CLVIII, Issue 23388, 20 December 1945, Page 4

RIVER CAUSING TROUBLE

Upper Reaches Of Rangitata Clyde Carrying Much Shingle When an inspection of the overflow problem of the Clyde River, which joins the upper reaches of the Rangitata, was made early this month by the chairman of the South Canterbury Catchment Board (Dr. P. R. Woodhouse) and the engineer to the Ashburton County' Council, both rivers were high and the overflow trouble was particularly pronounced, stated a report to the South Canterbury Catchment Board by its chief engineer Air G. R- Milward). In addition to the possible permanent severance of portion of the Arowyn Station, leased by Mr H. B. Hay from the Department of Lands, there was a considerable threat to the access by road, explained Mr Milward, who added that this was of vital interest to Mr Hay, the Lands Department and the Ashburton County Council. “The Clyde River, as is the case with all other rivers in this vicinity, is transporting large quantities of shingle each year and, as the riverbed is almost a mile wide, the river has had free play to change its course whenever the accumulation of shingle in one part causes an alteration in gradient.'’ continued Mr Milward. “It is apparent that in recent years the flow has veered towards the eastern side and is attempting to take a short cut where it has been at some period in the past, as evidenced by the topography of the country and the original survey maps. It appears likely that, unless some effort is made to block this overflow, the greater portion of the 3000 acres of country on the river flat will be severed and rendered impossible to work as part of the run; also, the access to the Arowyn Station will be destroyed, necessitating the expenditure of some thousands of pounds on a new road on a higher level.” Mr Hay had contended that without the use of the 3000 acres of flat land his run would be completely uneconomic. This fact, together with the road access, made it necessary that an attempt should be made to prevent the severance, concluded the report. The present indications were that this could be accomplished by a stop-bank, .approximately threequarters of a mile long, and at least two heavy groynes would be necessary, designed' to divert flood currents from the proposed bank. In addition to this work, some pilot channelling might have to be done to divert the flood flow toward the west side of the riverbed. At this stage it was not possible to estimate the cost accurately as the river had been too high to make the necessary surveys. It was not considered that any expenditure les sthan £l6OO would be of much value, and even then the fierce nature of the Clyde River in flood (clue to steep gradients) created certain hazards with any banking or groyne work.

The Board agreed, on the recommendation of the engineer, to seek from the Soil Conservation and Rivers Control Council an indication of what basis of subsidy would bo available for a problem of this nature, on an assumed estimated cost of £l6OO. It was also decided that a survey be made, when the river conditions permitted, in order to define more accurately the alignment of stopbank and groynes and to arrive at a more accurate 'estimate of the cost.