Classification of rivers

The two main types of rivers are rivers in hills and rivers in flood plains. Rivers in hills start from the mountains and flow through the hilly regions before reaching plains. Rivers in hills are of two types. They are incised river stage (rocky stage) and boulder river stage. Degradation process is responsible for flow channel in Rocky stage types. In Boulder river stage, river flows through wide shallow beds and interlaced channels and develops a straighter course. Rivers in flood plains or alluvial plains are of four types. They are aggrading, degrading, stable and deltaic. A silting river which forms a slope is known as aggrading river. In a degrading river, the river bed gets sourced constantly. In a stable type river, it is very difficult to find any significant changes in alignment, slope and regime. A deltaic river gets divided into branches before joining the sea. Based on flood hydrographs, there are two categories of rivers. They are flashy rivers and virgin rivers. Sudden flood rise and flood fall results in a flashy river. If the river water dries completely before it joins another river or sea is known as Virgin River.