Do deltas and alluvial fans form at the point of a river erosion?

Delta forms at the mouth of a river, where it meets a body of water, as sediment is deposited due to reduced energy levels. Alluvial fans form at the base of a mountain or hill when sediment is deposited by a fast-flowing river as it exits a narrow canyon or valley and spreads out over a broad, flat area. Both deltas and alluvial fans are landforms created by the deposition of sediment transported by rivers, but they form in different locations and under different conditions.