Task 2 - Velocity increases with increasing slope. This makes sense - if you increase the slope the water will move more quickly.

Task 3 - Discharge increases with slope. This also makes sense - if you are moving water more quickly you can move more of it in the same amount of time.

Task 4 - Velocity increases with increasing hydraulic radius. Hydraulic radius is the ratio of the channel area (A) to its wetted perimeter, so as you increase the hydraulic radius the water can flow faster because there is less drag by the wetted perimeter.

Task 5 - Velocity decreases with increasing roughness. This is expected, because the rougher the channel the more turbulant the flow, which will decrease the velocity.

Task 6 - Discharge decreases with increasing channel roughness. As the roughness of the channel i increases the turbulance of the water increases. This will make the water flow more slowly which will decrease the discharge. It is surprising that it changes the discharge so much, however.

Task 7 - If you were to be watching the Salt River at the downstream end of the Tempe Town Lake and the water were flowing across the location of the downstream dam that is 19' high and the channel width is about 850' and the channel slope there is 0.0013 (Arrowsmith actually calculated based on surveyed elevations in the channel), what would the flow velocity and discharge be (you estimate the roughness)?

I estimate the roughness of the channel to be between .020 (Straight unlined earth canals in good condition) and .025 (Rivers and earth canals in fair condition; some growth). The dam and the surrounding channel are pretty new and therefore likely to be in good condition. However, in the Google Earth Images it appears that there is some plant growth as well as some rocks and other materials which would add roughness. Based on these factors I estimated the roughness as .0225. Using calculation from Task 1 and the variables listed above I found the discharge to be 2.66 x 10^5 ft^3/sec, and the velocity to be 16.51 ft/sec.

Task 8 - If you were watching the Salt River at the downstream end of Tempe Town Lake and the water were bank full (to the top of the levees=40'), the channel width were 900' and the slope was the same as above, what would the discharge and velocity be (you estimate the roughness)? In 1993, the river was supposedly flowing at 100,000 cubic feet per second. Based upon your calculations, was it at bankfull?

I estimated the roughness of the channel in this case to be closer to .025. Since the water is in contact with the levees which are in good condition but appear more rough than the dams the roughness of the overall roughness of the channel should be increased. Using the variables outlined above I found the Discharge to be 8.54 x 10^5 ft^3/sec and the Velocity to be 26.38 ft/sec.