6 - Development and variation of riverscapes

Summary

The real voyage of discovery consists not in seeking new landscapes but in having new eyes

(M. Proust, 1871–1922)

Landscape analysis traces much of landscape evolution, long-term history, health of ecosystems

(Lewan, 2001)

The importance of Sense of Place

Introduction

The catchment, the river basin, contains all the natural capital of the land. The natural capital is what can be used and should remain. The sunlight and the precipitation (plus the other contents of the air and rain) reach the land. Land forms are made from rock. On them are subsoil, soil, alluvium, peat, water, glacial deposits and in, and above again, the biota. This is the capital of the land. There is a constant cascade of this natural capital downhill from source to sea (sediment, water, nutrients, carbon, nitrogen and other chemicals). Development is by the natural processes of the outside events acting on, and interacting with, the land form and what it bears. Impact alters this pattern, decreasing the productivity of the natural biota: by removing it. It may increase the productivity of people-chosen biota (e.g. wheat), or just increase the constructions of man (e.g. houses and streets).

Historically, serious impact begins when grazing domestic animals are sufficient to substantially alter vegetation, when crops are cultivated and the land is divided up, when settlement and communications are sufficient to disrupt vegetation patterns, and when rivers and other watercourses are changed enough to alter natural water regimes. At present, there are no satisfactory classifications of riverscapes.