Title
Comparison of historic & proposed channel patterns at the confluence of the Clark Fork & Blackfoot Rivers near Milltown, Montana
Abstract
The planform, or pattern, of a river represents how channel form adjusts in a horizontal plane. Channel planform is a continuum ranging from straight to meandering to braided, and is a function of sediment load, sediment size, and channel slope. Meander geometry describes the length, amplitude, and radius of curvature of a meander bend of a river. These characteristics are related to the width and dominant discharge of the river.
Conceptual restoration plans for the Clark Fork and Blackfoot Rivers through the Milltown area have been proposed by the State of Montana. These plans recommend a single thread channel, with a regular pattern, and repeating meander bend geometry for the restored river channels. The HISTORIC planform and meander geometry of the Clark Fork and Blackfoot Rivers through the Milltown area are depicted in late 19th century and early 20th century maps, and are markedly different from the PROPOSED planform and meander geometry. Why do these proposed and historic planforms and meander geometries differ?
Start Date
1-4-2005 1:00 PM
End Date
1-4-2005 3:00 PM
Document Type
Poster
Comparison of historic & proposed channel patterns at the confluence of the Clark Fork & Blackfoot Rivers near Milltown, Montana
The planform, or pattern, of a river represents how channel form adjusts in a horizontal plane. Channel planform is a continuum ranging from straight to meandering to braided, and is a function of sediment load, sediment size, and channel slope. Meander geometry describes the length, amplitude, and radius of curvature of a meander bend of a river. These characteristics are related to the width and dominant discharge of the river.
Conceptual restoration plans for the Clark Fork and Blackfoot Rivers through the Milltown area have been proposed by the State of Montana. These plans recommend a single thread channel, with a regular pattern, and repeating meander bend geometry for the restored river channels. The HISTORIC planform and meander geometry of the Clark Fork and Blackfoot Rivers through the Milltown area are depicted in late 19th century and early 20th century maps, and are markedly different from the PROPOSED planform and meander geometry. Why do these proposed and historic planforms and meander geometries differ?