Because the Width and Depth both increase downstream. This means the wetted perimeter will also increase.
steamboat
steamboat
Oars
All rivers that flow downstream are capable of producing hydroelectric power.
Width will increase as you go downstream due to the process of erosion and sediment deposition. As a river flows, it erodes the banks and bed, widening the channel, especially in areas with lower gradient. Additionally, the river carries sediment that can accumulate in certain areas, further contributing to a broader channel. This dynamic interplay between erosion and sediment deposition leads to the characteristic widening of rivers downstream.
Oars
They reduce flow, and create a backpool which reduces flow downstream
Rivers carry silt downstream and build deltas.
Rivers carry silt downstream and build deltas.
No. The water flows downstream. Correction, I believe the Amazon flows upstream
soil flow
Since we have no idea what "this" might be, we can't answer the question properly.