Introduction

Chapter 2 discussed the natural river and its destruction. Many streams have been totally destroyed in the past c.150 years (dried and gone) and more have been destroyed ecologically, having an inadequate, or almost gone, biota. Since the riverscape is needed for people to live on and grow their food on, it is seldom destroyed (by, e.g. quarrying it away), but is instead modified. While water is the medium of the river, the riverscape is mostly in the mediums of air and soil, with water a small, though essential component. However, it is the river (or glacier) that has made the riverscape! And it is the river which makes (or made) its pattern, with its network flowing downstream.

In the long term, the river moves the riverscape to the sea, but this time-scale need not be considered here. The river does, though, move water, energy, sediment, nutrients, debris, pollutants and biota. All move downstream, except for animals with independent mobility, and plants moved by animals or wind.

A riverscape, being so much larger than a river, has even more complex influences.