Why does a mature river have more discharge than a youth full river?

A mature river has more discharge than a youthful river primarily due to its wider and deeper channel, which allows it to carry more water. As rivers mature, they erode their banks and beds more extensively, increasing their capacity. Additionally, mature rivers often have larger watersheds that contribute more tributaries and runoff, enhancing overall discharge. In contrast, youthful rivers are typically steeper and narrower, resulting in lower discharge rates.