Distinguish between.
(i) River basin and Watershed.
(ii) Delta and Estuary.

(i) River basin and Watershed.

Ans. Watershed : Watershed is an area which is drained by a river. It is demarcated by a line that separates the watershed of one river from the adjoining ones. These are small areas less than 1000 hectares.

River basin : The watersheds of large rivers are called river basin.

(ii) Delta and Estuary.

Ans. Delta : A delta is a triangular piece of alluvial low land formed at the mouth of the

river. It is formed due to deposition by the river at its lower course.

Estuary : Those rivers which do not form deltas, form estuaries. These rivers do not deposit sediments on their mouth, and carry the materials into the sea or ocean. This mouth is called estuary. Example : Narmada and Tapi make estuaries.