Side Valley - Basic Facts of Geomorphology

Basic Facts of Geomorphology

However, the term "side valley" is used rather for higher order valleys near the mountains (example above: the Pennines), for the lower valleys often do not show a drastic relief. The reason is a simple one: The "mainstem river" (into which the secondary river flows) passes much more water than its tributaries and therefore

• has a lower current (see Hydrology)
• much more fine sediments
• which are deposed in a more flat matter.

The higher the order of a valley, the steeper usually are the hillsides resp. valley slopes. Looking upstream, the steepest slopes are normally near the source of a brook (with the exception of very hard rocks in downstream direction).