Rivers with an abundant gravel or sand sediment load were classified as bedload rivers by Schumm (1963). They are usually described by the term “braided”, but in its common useage this term is misleading, because it hascome to imply only rivers of low sinuosity (less than 1.5, using the classification of Rust, 1978a). However, bedload rivers with higher sinuosities are relatively common. They may have stable islands and branching channels, and therefore do not fall conveniently into either the braided or meandering categories. Examples are described by Bluck (1971), Gustavson (1978) and Forbes (1983). They are encompassed by architectural model 4 of Miall (this volume) and will be described briefly below.

The terms alluvial fan and fan delta are widely used in the geologic literature. They carry specific geomorphic implications about the dispersal of the water and sediment in a series of distributaries, but these characteristics often cannot be demonstrated from the ancient record. Lithofacies assemblages typical of gravelly alluvial fans, such as the Trollheim and Scott types of Miall (1978), corresponding closely to architectural models i and 2 of Miall (this volume), are found both in alluvial fan and braidplain settings. The terms alluvial fan and fan delta should therefore be used with caution when describing the ancient record. The sedimentology of these environments is dealt with by Ethridge (this volume) and Galloway (this volume), and will therefore not be covered in this chapter.

The remaining “braided” models of Miall (1978), comprising architectural models 3, 4, 9 10, 11