Huvudfåra

Huvudfåra is a Swedish term used in hydrology and geomorphology to describe the main channel or dominant bed of a river or drainage system. It refers to the principal path along which the largest share of water and sediment is carried, forming the main stream that shapes the surrounding valley.

The huvudfåra develops through long-term fluvial processes, including erosion, sediment transport, and bedrock interactions. Its course is influenced by gradient, lithology, vegetation, and climate, and it can be bedrock- or alluvium-controlled. In cross-section, a huvudfåra is typically deeper and wider than side channels, and it may be straight or meandering. Over time the channel can migrate through processes such as avulsion, where the active flow shifts to a nearby path, or through gradual incision and widening.

In river networks, the huvudfåra collects flow from tributaries and distributes discharge along the watershed. Side channels or smaller streams may join or diverge from it, but the huvudfåra remains the central conduit for the main drainage. Its identification is important for hydrological modelling, flood risk assessment, sediment budgeting, and river restoration projects, as it represents the primary pathway for water and sediment transport.

The concept is applicable to various landscapes, including floodplains, valleys carved by rivers, and basins shaped by long-term erosion. Understanding the huvudfåra helps explain how landscapes respond to climatic events, land-use changes, and natural shifts in the drainage network.