For the series pipe system in Example 4.15 , find the equivalent roughness coefficient and the total head at point D for a flow rate of 0.03 m³/s.

Data from example  4.15 For a flow rate of 0.04 m3/s, determine the pressure and total heads at points A, B, C, and D for the series pipes shown in Figure 4.18 and Table 4.11 . Assume a fully turbulent flow for all cases and the pressure head at point A to be 40 m. Determine the length of an equivalent pipe having a diameter of 1,000 mm and f equal to 0.025 .

Z = 32.5 m Z = 37.5 m Z=20 m Z=25 m A B C D FIGURE 4.18 Compound pipe system of Example 4.15.