1 School of Geography, University of Leeds, Leeds, UK, LS2 9JT
Tel: ++44 113 2333318, Fax: ++44 113 2333308, Email:
steve@geog.leeds.ac.uk
2 Department of Geography, University of Southampton, Southampton, UK,
SO9 5NH
Tel: ++44 1703 594614, Fax: ++44 1703 593729, Email: d.sear@soton.ac.uk
Abstract
This paper outlines a GIS approach to modelling laterla instability in river channels as a means of risk assessment in flood plain management. The work of Graf (1981, 1984) and Hooke and Redmond (1989) in modelling lateral instability in gravel bed rivers is adapted to produce risk maps through the incorporation of impedance models and land value information. Graf's raster based probabilistic approach to predicting instability on the basis of historical data derived from old maps and aerial photographs is adapted and vector alternatives investigated. Improvements to model predictions are made through the development of basic rule based impedance models describing the effect of changes of bank material, riperian vegetation, topography and river engineering on channel movement and instability. Results from the combined models are integrated with land use maps tagged with land value information in order to estimate risk in relative monetary terms. test case examples from the River Wooler and River Ure in northern England are presented and used to evaluate the potential of the technique as a tool for flood plain management.