MODELING RIVER CHANNEL TOPOGRAPHY USING GIS

The modelling of environmental processes based on catchment elevation surfaces is well-established, but the use of TIN and grid surface mode ls as three-dimensional representations of river channel topography at the reach scale is much less common. In this paper, surface modelling facilities in ARC/INFO GIS have been used to model the geometry of se ven short sections of gravel-bed river channels in upland Britain from held surveys taken in 1976 and 1994. The methods used in converting f ield survey data and implementing bed-topography models as TIN and gri d data structures are described. The use of derived surface models to define pool-riffle bedforms, estimate sediment budgets and assess chan nel change between surfaces of different dates are discussed and evalu ated.