Steep valleys descend from the higher country to join the main valley and at the mouth of every tributary is an alluvial fan.
Half an hour's walk brought us to Vista Alegre, another little clearing on an alluvial fan in the bend of the river.
In their place an extensive delta and alluvial fan have been formed.
Undoubtedly this alluvial fan had been highly prized in this country of terribly steep hills.
A fan-shaped mass of sediment, especially silt, sand, gravel, and boulders, deposited by a river when its flow is suddenly slowed. Alluvial fans typically form where a river pours out from a steep valley through mountains onto a flat plain. Unlike deltas, they are not deposited into a body of standing water.