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5. (a) With respect to hydrograph routing. explain the underlying difference between "river routing" and "level pool routing" [3 Marks] (b) A dam is to be constructed to form a new reservoir. The dam spillway is 35m in length and has a crest elevation of 57.4 m. The spillway outflow (0) can be calculated from: 0 = 1.7Lh", where O is in m/s, L is the spillway length (m) and his depth of water above spillway crest (m). Table 1 shows the routing curve data for the reservoir. TableQ5- 1 Monthly flow volumes Outflow 05 15 28 436078 120 (m/s) 25 0 +O 139284433588 751 | 923 | 1104 | 1292 (m/s) 99 7 8 9 10 | 11 0 (i) Construct the reservoir routing curves. [4 Marks) (ii) Assuming that the reservoir is initially full, route the inflow hydrograph shown in Table 2 through the reservoir until time = 10 hours. [12 Marks) TableQ5- 2 Monthly flow volumes Time (hr) 0 1 2 3 4 5 6 Flow 0 8 34 116 200 195 168 114 61 27 8 (mºs) The following equation may be useful 25 At At (iii) What is maximum head of water over the spillway and the maximum expected water surface elevation? [4 marks] (iv) Determine the values of translation and attenuation. [2 marks] 28 0.1-[204 +0: