Contenu du sommaire : Les paysages des cours d'eau

Landscape studies are requested increasingly by managers and planners although they appear infrequently in global studies of rivers. In this article we propose a conceptual and methodological approach to landscape diagnosis of fluvial hydrosystems. It is based on a quantified analysis capable of being approved by all the actors concerned and of being reproduced. Having discussed the conceptual basis of our approach, we suggest a range of methodological developments capable of replying to different landscape issues. The results of the analysis of micro-landscapes on the river Rhins, a tributary of the Loire, are also presented. They were obtained by the visual analysis of photographs, the composition of which is described by data analysis to determine different micro-landscape types.

Today, water resources are both of fundamental importance and under threat. Rivers are increasingly perceived as essential landscape and heritage features. Economic necessity, social demand and ecological imperatives render essential the careful management of water systems. Such recognition has been accompanied by regulatory measures at a national and European level. Faced with new regional planning and development problems, landscape specialists are increasingly in demand, especially in urban and urban fringe areas. This article explains the importance, in this field, of working to objectives, of basing subsequent landscape proposals and actions on these objectives and of using an appropriate scale of working, taking account of a certain number of methodological constraints and principles. It shows the role of the practicing landscape planner who now intervenes as a key actor in questions of river management. The conception of a landscape study, viewed from the outset as a means of mediation, can provoke a territorial process, creating awareness amongst all the actors around a comprehensive and well- conceived project, as well as preparing the introduction of a landscape charter.

After defining landscape in the context of this paper, criteria for landscape analysis are presented based on characteristic features of the landscape which give it sense. The relationships between time and landscape are discussed, before presenting a new approach to landscape analysis known as "spectrography". By examining questions on the mean of interpreting landscapes and on landscape itineries, as well as on their visibility and accessibility, methodological questions are raised concerning the conditions under which landscapes are analysed. It is argued that time cycles and itineries are two aspects that should be developed in landscape assessment.

The course of the river Gartempe straddles the Limousin massif and the sedimentary basin of Poitou, revealing through its landscapes contrasting physical characteristics from upstream to downstream : the steep sided valleys of Limousin precede the vale of Poitou. These contrasts relate to clear functional differences, reflected in the landscapes. The landscape values of the river have been inverted as the economy has been weakened by the decline of this rural region. Formerly repulsive areas are promoted as attractive sites. Certain sections of the river, having lost their economic interest, have suddenly been endowed with a heritage value responding to other demands born from a leisure-based society. Will the commercial value of the river's landscapes, through green tourism, be able to replace obsolete economic activities ? The "landscape hallmark" attributed to the Gartempe shows rather the interest of a river lanscape as a safe value for a society in search of its roots. Finally, a methodological approach provides a synthesis of the factors used to determine the quality of river landscapes. The identification of landscape markers is simplified by a graphic and spatial representation applied to the Gartempe.

The aesthetic and functional restructuring of Delaware's waterfront, linked to the rapid growth of communications and urban marketing, is of permanent concern to the decision makers of Philadelphia. This area represents as much the crystallization of an historic heritage as a symbol of society's collective memory. It has been redeveloped successively, evoluing at present towards activities linked to business tourism and a postmodern aesthetic quality. This article suggests a different interpretation of American waterfronts, paradigmatic places at the interface between urban areas and rivers.