AGGRADED RIVER BEDS

Evening Post, Volume CIII, Issue 54, 6 March 1922, Page 6

AGGRADED RIVER BEDS

In these days of February frosts and March floods, meteorological peculiarities are at a discount; but the recent phenomena of swollen yellow rivers may give point to a contributed article in Saturday's issue, pointing out that the deforestation of steep land at the headwaters of rivers leads to a whole heap of consequential trouble. Deforestation makes water-flow -more irregular and facilitates the erosion of the hill slopes. The torrents that carry the slipped earth may not be able -to transport it the whole journey ; as ' they; approach the level country and lose velocity, they drop their load, but this deposition raises the. river-beds, and compels the rivers to invade lowlying land that otherwise would not have been attacked. Aggraded river-beds are presenting a growing problem in many parts of the country, and the original cause is in most cases the deposit of earth and rock set in motion by the fast falling mountain torrents. To put the thing concretely: if the Urewera watershed of Bay of Plenty rivers is deforested, the eroded matter, does not need to reach the lowest plains in order to cause thenowners trouble. The trouble, indeed, may not arrive on the coast till many years later. But it will arrive.