Waimakariri Shingle

Press, Volume CIX, Issue 31983, 9 May 1969, Page 10

Waimakariri Shingle

Sir,—The deposited shingle in the lower Waimakariri is widely recognised in Christchurch as a potential danger through reduced channel depth in flood time. Some years ago over a million cubic yards, by survey, was set down by a single flood. The river control and neighbouring local bodies should investigate the capital costs and probable maintenance and wage bill for a really sizeable extraction and crushing plant. There is sufficient recorded experience to make possible an estimate of the life of such a plant. Costs spread over such a period would result In aggregate at a low price on yardage. At relatively small expense the community could have a double benefitunlimited shingle supply and some additional flood control. Incidentally, with present experiments in coastal barge traffic, the idea of the late Mr L. C. Walker of having the Waimakariri shingle transported to supply Wellington shortages at reasonable rates, is not now as visionary as once supposed. As an engineer, Mr Walker was aware of the technical requirements of such a proposal.—Yours, etc., D. K. BOYD. Ashburton, May-7, 1969.