TIMARU AIRPORT

Press, Volume LXXIII, Issue 21992, 16 January 1937, Page 12

TIMARU AIRPORT

MODEL OF SALTWATER CREEK OUTLET

EXPERIMENTS BEING MADE TO AVOID BLOCKAGE

One of the problems in the construction of the Timaru airport—the satisfactory diversion of Saltwater creek and the building of an effective outlet to the sSa—is now being investigated by the Public Works Department at Temuka £ model on' a 1 in 40 scale has been made to reproduce conditions on the. b£ch, including the drift of shingle along the beach from the action ol waves and the consequent tendency to the blockage of the proposed culvert outlet. , To test the comparative values ol different culvert types, fine sand and shingle have been placed in tne model and waves are created by a paddle operated from an electric motor. The problem confronting engineers will be to avoid internal blocking within the closed culvert caused by the wash or drift _ ol shingle, and to avoid the formation of bars and lagoons on the beach. A further .consideration is the lacK of a regular flow down Saltwater creek, and its tendency to flood after rains. A blockage outside the culvert cannot •be prevented, but it a satisfactory- model is found, the culvert will be built on that plan and shingle accumulating outside will have to be cleared periodically. The model beach and culvert is believed to be the first of.its type to be used in construction work in New Zealand, and engineers in charge already claim some measure of success in the problem it is instrumental in solving. Where a similar experiment on full scale would cost up to £9OO, experimenting with the model involves a total cost about £2. The actual culvert will be 300 feet in length, and more than 50 feet wide. Tests are being made to find the most suitable angle at which to place the culvert and to find the most effectively shaped design. '