Lavsed - A Model for Predicting Watershed Erosion and Fine Sediment Transfer in Northern Water Streams.

Computer modeling techniques are used for predicting soil losses from overland flow and subsequent suspended sediment yield from large watersheds. The model LAVSED-I (LAVal SEDidentological model No. I) is based on the universal soil-loss equation of Wischmeier and Smith and the equation of Kilinc and Richardson. The model subdivides the watershed into square units varying in size from 0. 3 to 3000 km**2 and the computational procedure is subdivided in four components: precipitation, physical characteristics of watersheds, erosion/sedimentation, and land use. This paper describes the operational development and the application of the model to a prototype-scale watershed. A map for the annual soil loss is presented for the Chaudiere watershed (area equals 5830 km**2). Results of mapping compared with the sediment yield observed are shown in the paper.