SOIL EROSION

Te Awamutu Courier, Volume 54, Issue 3906, 28 May 1937, Page 2

SOIL EROSION

EFFECT ON RIVERS. In addition to damaging farming lands the effect of erosion on rivers and water storage dams must be considered. Solid washed from undulating and hilly lands silts up stream beds, dams, and resevoirs. No water storage schemes for irrigation, hydroelectric power, stock or domestic purposes. are safe and permanent until accelerated erosion in catchment areas is checked. The water in American rivers is either yellow or brown with mud, even during a drought. . It is not difficult to visualise what the watersheds are like. They were found to be partly denuded of trees, there was too much cultivation of solpcs and insufficient areas of grass and forest, consequently erosion was active. Yet there is conclusive proof that many of these rivers were once free from mud. Early explorers and surveyos constantly recorded the remarkable clearness of ’the waters, but at that time, of course, the catchments were covered with vegetation and there was, consequently, no accelerated erosion. As a direct result of soil erosion and increased run-off on the catchment areas, rivers, are carrying a much greater quantity of silt, soil and sand, which is aising the beds of rivers. Bank erosion is severe, the streams cutting back into rich alluvial flats. The height of floods has also been greatly increased. Some streams have even been sanded up and have disappeared.