Abstract

Đà River is a large river originating from Yunnan province in China and flowing through Northwest Việt Nam with a length of 527 km. It flows mainly in northwest- southeast direction but in its downstream section from Hòa Bình it changes the direction to the north and merges with the Red river at Việt Trì. This paper presents the results of research in the Đà River valley from Hòa Bình to Việt Trì with the semi-automated geomorphologic mapping, analysis of some types of landform and their interaction with the geological formations. The results obtained show that the topographic surface is highly dependent on the geological formations and based on this various landforms such as denudational, erosional, tectonic, etc. have been more accurately identified. The paper also gives an interpretation on the age of the Đà river valley, which shows that the downstream valley of the Đà river just appeared in the Middle Pleistocene.