# Exercise 15 Solution

1. A string could be streched across the channel in both images and a line level used to ensure the string is level. Then the depth of water measured at constant widths from the edge of each side. This could be transferred to drafting paper and used to calculate both the cross sectional area and the wetted perimeter.
2. A tape measure could be used to measure the perimeter of the conduit cross-section for the wetted perimeter at full flow in both channels, much like the above exercise, but more measurements required, and the string stretched across the widest space.
3. The wetted perimeter increases as the conduit fills but remains constant once full. Higher discharge must occur to completely fill the conduit. All three would increase. However, this channel is more like a circle shape.
4. Like the above channel all three would be increasing. However, since this channel seems to have a small rectangle that is cut into the wider channel. As the water tops that first smaller downcut channel the wetted perimeter will suddenly increase and it will take much more discharge to raise the water level over this even wider channel, also the cross-secional area divided by wetted perimeter will not change at the same rate as for the smaller channel at the lower flow.