Demonstration of Erosion Control

Manawatu Times, Volume 70, Issue 192, 15 August 1945, Page 6

Demonstration of Erosion Control

INTERESTING CEREMONY AT TE AWA GULLY

An Arbor Day demonstration which incorporated various control measures for gully erosion was conducted by the Manawatu Catchment Board at the site of vicious erosion on tho Te Awa Road, Pohangina County, yesterday afternoon. Favoured with brilliant spring weather, there was a large attendance of local body representatives, farmers, Massey College students, Rehabilitation Department farm trainees and boys from the Feilding Agricultural College. Under the supervision of Mr. E. Bruce Levy, Director of the Grasslands Division of the Department of Scientific and Industrial Research, and a Government appointee on the Catchment Board, tree planting as a means of combating erosion in the Te Awa Gully has recently been implemented. As they drove up to the site of the demonstration, the visitors were able to see the full extent of the ravages caused in that area by erosion. A huge wash some 50 yards across by 50 yards deep has been gashed out of the soft sandy soil (marine formation) and there were plenty of signs that the scouring is continuing. The demonstration began at the head of the gully erosion where control measures have been started. The immediate head had been filled with manuka to prevent further spreading backwards into the pastureland. Below this where the wash had begun to assume depth, four debris dams had been constructed. The slopes on either side had been spot-planted with willows, poplars and aspens to arrest slumping and slipping of soil on the hillsides, while nearby gullies had been planted with trees to avoid any possibility of erosion starting. Mr. Levy, in describing the nature and purpose of the work already undertaken, said that insofar as the Te Awa erosion was concerned, their efforts were rather like closing the stable door after the horse was out. The erosion had assumed very extensive proportions and he was not able to say whether the plantings and the debris dams would now prove effective in combating it. The work was largely experimental, but the important thing was that efforts were being made to meet the menace of erosion. On the easier slopes trees had been planted at a density of three per acre, while on the steeper slopes the rate had been increased to ten. A farmer in Poverty Bay had claimed that up to 25 per cent, increase in stock carrying was possible by poplar and willow plantings on hillsides. Poles, said Mr. Levy, were the most suitable for planting and these had to bo protected from stock. The protection methods used at Te Awa were the wrapping of manuka round the poles, bound with barbed-wire, and inch netting. Both had proved suitable. In a short ceremony five trees were planted along a gully fence line by Mr. J. T. J. Heatley, chairman of the Manawatu Catchment Board, Mr. J. Callesen, a member of the Rivers Control and Soil Conservation Council, Mr. W. McKay, chairman of the Pohangina County Council, Mr. W. G. Clapham, Kiwitea County Council, and Mr. \V. S. Romlcy, Oroua County Council. Some essential details of debris dams were then given by the engineer to the Manawatu Catchment Board (Mr. J. B. Halley) who explained that their purpose was to hold the silt and allow the water to filter on down the gully. In this way a series of terraces would be built up. Once the bottom of the gully was held, the slopes on either side would become stabilised and large slips of land would not occur. A short address on the value of timber to the farmers and to the country as a whole was given by Mr. S. A. C. Darby, Conservator of State Forests, Palmerston North.