If you can't swim to the bottom then get a super long pole made of dry wood then put it into the river until it stops when you pull it out measure it with measuring tape
the bottom of the river is called a bed
The bottom of the river is called the river bed.
The bottom of a river is called the river bed.
River Bottom - album - was created in 1981.
the bottom of a river
The bottom.The "bed" of a river is the bottom or floor of the river. It is where silt can accumulate and where bottom-feeding fish live.
The river bed
The river bed.
The Colorado River
accumulated sediments on the bottom of the river
Because the pieces of rock are eroded a it passes down to the bottom of the river.
on the slope down from the top of the river, to the bottom of the river