How can rapid tectonic uplift lead to rapid river downcutting?

Rapid tectonic uplift leads to accelerated river downcutting through a process known as rejuvenation. When vertical uplift occurs, it increases the elevation of the land, which simultaneously reinvigorates the erosive power of existing rivers by increasing their potential energy.1

As the land rises, rivers attempt to adjust to their baselevel—the lowest point to which they can erode—by cutting downward into the bedrock to maintain their longitudinal profile. This accelerated vertical entrenchment is what creates deep canyons and gorges. The intensity of this downcutting depends on the rate of uplift; if the rate of river incision can keep pace with the rate at which tectonic structures rise, the river will continue to cut through the uplifting rock, often resulting in transverse canyons that cut across major structural trends.231