Agricultural irrigation uses a significant amount of water, and in some regions it has overwhelmed other water needs. Suppose water is drawn from a reservoir and delivered into an irrigation ditch. For most of the length of the ditch, the delivery is through a 10-cm ID pipe, and in the last few meters the pipe diameter is 7 cm. The exit from the pipe is 300 m lower than the pipe inlet. 

(a) Assume that the pipe is smooth (i.e., ignore friction) and that the delivery rate is 4000 kg/h. Estimate the required pressure difference between pipe inlet and outlet. How far below the surface of the reservoir is the pipe inlet? 

(b) How would your answer be different if the pipe were not smooth? Explain. 

Exploratory Exercise—Research and Discover

(c) What are possible environmental impacts of diverting significant quantities of river water for use in irrigation? Cite at least two sources for your response.