What is a wetted perimeter in geography?
Wetted Perimeter is the measure of how much water contact there is with the bed and the banks of a river. This should also increase downstream as water feeds into main streams from tributary rivers. Hydraulic radius is a measure of how efficient the channel is at transporting water and sediment.
How do you measure wetted perimeter in geography?
Wetted perimeter can be measured using a heavy chain, rope or measure tape, which should be stretched across the river bed from one bank to the other. This can be hard to do, especially in larger channels or where the bed is very rough. Fast flowing water conditions can also be problematic.
How does wetted perimeter change downstream?
This is because a river tends to become deeper, wider and have a higher discharge the further downstream it moves. As a result relatively less water is in contact with the wetted perimeter, so friction on the river water from the bed and banks of the channel is reduced downstream and it consequently flows faster.
How do you find the wetted perimeter of a river?
The area of the flow will be equal to the channel width, b, multiplied by the flow depth, y. The wetted perimeter, on the other hand, is simply the total length of channel walls which are in contact with the liquid. In the case of the rectangular channel, it’s a sum of b + y + y.
What is wetted perimeter and hydraulic mean depth?
The cross section of water flowing through a channel or pipe divided by the wetted perimeter of the conduit.
What is the wetted perimeter hydraulic radius?
The wetted perimeter is the perimeter of the cross sectional area that is “wet”. The term wetted perimeter is common in civil engineering, environmental engineering, hydrology, geomorphology, and heat transfer applications; it is associated with the hydraulic diameter or hydraulic radius.
Why does Bedload size decrease downstream?
This is because the further downstream material is carried then the greater the time available for it to be eroded by attrition and abrasion which makes rocks and stones smaller and rounder.
How is river discharge measured GCSE?
Using a tape measure, hold one end at the point where the water meets the bank one side of the channel. Ensure the tape is not twisted pull the tape measure across the river and measure to the point where the water meets the bank directly opposite.
How do you measure the width of a river without crossing it?
Measure from the ground to your eye level. Sight along the edge of the meter stick to the opposite bank. Measure the angle that the edge of the meter stick makes with vertical (represented by your body). Your eye-height, multiplied by the tangent of that angle, will be the width across the river.