Disastrous floods have been the portion of most of the provinces of New Zealand at some time or another. The cost in property and lives has been heavy, but the saddest fact of all is that many of the scars the country carries can be regarded almost in the light of self-inflicted wounds. The wholesale and frequently ill-considered denudation of natural forest and the unnecessary destruction of native bush, with a consequent interference with huge watersheds and nature's protective coverings, have led to widespread erosion.

Most of the larger rivers have their records of devastation, and for many years some of them have been a perennial menace. If the incidence of their destructive flooding has today been reduced, it can be attributed mainly to a vigorous better-late-than-never policy of river control and soil conservation which is beginning to have its first visible effects. The more troublesome rivers have exhibited an expensive persistency. The Waikato River in the north has created havoc along the whole of its great length and the Manawatu River, with its tributaries, has been no less active over a wide territory, both rural and urban. In the Wairarapa the Ruamahanga River has a long flooding history, and the Hutt Valley has suffered heavily from the river that traverses it. In the South Island, the Clarence, the Rakaia, the Rangitata, and the Waimakariri Rivers have often been a scourge to Canterbury, and in Otago the Taieri and Clutha Rivers have year after year caused serious damage on Taieri Plains and in the Balclutha and Inchclutha areas. In Southland the Mataura River enjoys a similar reputation.