Water resource engineering
Question 1. Prepare a table of plotting points for IDF curve for 2, 5, 10, 15 and 20 -year for the rainfall record shown in the table below. Show all the calculations and draw the curves in an Excel sheet.
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Rainfall record (1 Jan. 1960 - 31 Dec. 2007)
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Number of storms intensity or more
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Duration (mm)
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Intensity (mm/h)
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20
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30
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40
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60
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80
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100
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120
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140
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160
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180
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200
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5
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|
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252
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56
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18
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8
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5
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3
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10
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265
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71
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21
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9
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5
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2
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15
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248
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99
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22
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8
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4
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2
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20
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255
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92
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37
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12
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6
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4
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2
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30
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211
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49
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19
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10
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3
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3
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1
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40
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78
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33
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9
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2
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50
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33
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13
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3
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60
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9
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2
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Question 2. Melbourne polytechnic has proposed that a baseball park to be built in its Epping campus. A site on a 12-ha pasture has been selected. Drainage from the site passes through a culvert under existing road. The capacity of culvert is not known. The university highway department uses a 5-year return period for design of culverts for this type of road. From the topographic data of the site, the overland flow estimated to be 2.00 percent, and the runoff coefficient is estimated to be 0.20. Using the IDF curves Melbourne, estimate the peak flow capacity of the existing culvert in m3/s.
Question 3. The proposed parking lot for the baseball park (Problem 2) will occupy 2.55 ha of the site. It will be graded to a slope of 1.80 percent. The overland flow distance will be 200.0 m and the runoff coefficient is estimated to be 0.70. Ignoring the runoff from the pasture, determine whether the existing culvert has the capacity to carry the peak flow from the parking lot from a storm with a 5-year return period. Use the IDF for Melbourne.
Question 4. Determine the unit hydrograph ordinates for the Convex River flow data shown below. For ease of computation the total ordinates are tabulated below the hydrograph. Note that the base flow may be determined by simple graphical extrapolation. The area of the watershed is 100ha. Note that the time is military time, that is, 1500h = 3 PM, 2000h = 8PM etc.
