Methods of historical river channel change reconstruction and their application to applied geomorphological research

Abstract

This thesis examines the geomorphological significance of scale in space and time to provide a conceptual basis for understanding river channel change. This allows the investigator to evaluate the demands required in seeking answers to river channel change questions that are appropriate to the nature of the geomorphological enquiry. To achieve these requirements, the thesis considers the nature and magnitude of errors associated with a range of historical sources of information. Methodologies are presented which demonstrate how planform, cross-sectional and ground-based historical photographic information may be used to extrapolate river channel change for three morphologically different rive channels in England and Wales (the rivers Towy, Sence and Tillingbourne respectively). The type of historical information is demonstrated to be appropriate to the nature of the channel adjustment in order to yield valuable information to aid the interpolation of patterns of past channel behaviour.The contribution of historical geomorphological techniques to aid river channel management is considered The example of the River Wey is used to demonstrate how a suite of historical sources of information may be used in conjunction with contemporary field observations to address specific river channel management challenges. A GIS-based method of compiling and manipulating multi-type historical information is demonstrated an effective aid to the interpolation of river channel change. Historical information is demonstrated to be effective in providing a historical context for understanding contemporary patterns of river channel behaviour and developing appropriate recommendations for management. The successful application of applied geomorphological expertise is demonstrated to be as much a reward of effective communication as geomorphological interpolation.The wider implications for the research is considered through the considerations of the practical challenges for the effective integration of historical geomorphology with river channel management and proposes a series of recommendations based on the findings of this research.</p