CAUSES OF FLOODS

Dominion, Volume 28, Issue 232, 28 June 1935, Page 12

CAUSES OF FLOODS

Destruction by Deer in Watershed Areas PROBLEM IN HUTT VALLEY More serious floods in various parts of New Zealand are predicted by a widely travelled observer, whose duties take him from one end of the Dominion to the other and far into the hills and mountains where rivers begin. He has just completed a tour lasting many weeks into the inland areas of the South Island, where deer-slaying operations have been carried out by ollicial hunting parties. Speaking to a reporter upon.his return he said that the damage done by deer was evident over very wide areas. The destruction of the forest floors, shrubs', and mosses holding water and binding earth and rocks together was having a very serious effect. “I personally know of vast areas of forest where this has resulted in entire cessation of natural regeneration of forest and shrub life and where the protective covering of the forest floor has been trampled until nothing remains of what used to be a complete forest community, but the trunks of big trees and the roof of the forest. That eventually leads to serious flooding, and there is not the slightest doubt that in New Zealand this will lie a national menace if drastic action is not maintained. Wellington I’vovinbe Affected. "The case is evident right at outown door here in Wellington. The Ruamahunga River that rims through the Wairarapa plains causes frequently, A visit to the upper reaches where the river flows through bush-clad mountains reveals that a great deal of damage has been done by deer, so that the ‘run off’ of water is not controlled and. restricted as it should be naturally by ■ retention in mosses at the roots of ferns and shrubs. Big slips are occurring because there are now no roots to bind the earth together. Deer trampling the ground, eating leaves and stripping the trees of bark with thpir jaws and their antlers are the causes. "The spread of this condition will lead to timber coming down the rivers together with enormous quantities of soil and gravel. That means that far more serious flooding will occur as time goes on if the deer are not kept under complete control. The truth is coming nearer to home. Increasing floods in town areas are affecting trade and commerce through holding up business and darffaging stock in the shops in some cases. "The method being used to prevent flooding has been to erect groins and raise the banks of rivers. But that is merely closing the door after the horse has escaped. The problem must be tackled higher up irf the mountain and bush areas. The position is being realised by more people. The Waimakariri River Trust has lieen put to very great expense to cope with flooding. Last year the board gave £2OO to the Government toward the cost of exterminating deer in the Waimakariri watershed areas. That is getting down to the roots of the problem. If the bush and the floor of the forests in the mountain gorges were left alone, they would effect the remedy. Control of the deer will ensure that the conditions right themselves. Hutt River a Problem. •‘The Hutt River is a problem for Wellington and the Hutt Valley. The Hutt Valley has been definitely menaced. A big sum has been expended in erecting groins and doing other work in the valley to stop the river from excessive flooding. People' would be amazed to see what is going on up in the mountains about Mount Alpha and Mount Omega. The Quoin Ridge lies between the two branches of the Hutt River at its source area, and a great number of deer have been killed this season in that area. “I am quite confident that the deerkilllng operations so far carried out will check any increase of the difficulties. In the Hutt watershed areas great progress has been made this season in reducing the number qf deer. But there are still hordes bf deer there.”