- A For The Catchment In The Figure Below And The Gauge Locations As Shown P1 P7 Calculate The Thiessen Polygon Weights 1 (97.09 KiB) Viewed 31 times
a) For the catchment in the figure below and the gauge locations as shown (P1~P7) calculate the Thiessen polygon weights assigned to each gauge. Show your construction and final polygon boundaries on the figure below [5 marks] Each grid is a square of 1x1 km and of equal area. Write and draw your answer on the diagram below. P4 P2 P7 -P6 P5 Catchment boundary LLLLLL b) A rainfall event has occurred on the catchment shown in Question a) above and the rainfall that was recorded at each gauge is listed in the following table. The losses from this storm event are Initial Loss = 25 mm and Continuing Loss = 5 mm/hr. Calculate the total volume of runoff from the event using the Thiessen polygon weights previously calculated. [7 marks] Time P1 P2 P3 P4 P5 P6 P7 (hours) (mm) (mm) (mm) (mm) (mm) (mm) (mm) 0 3 7 3 5 10 0 30 22 18 22 20 15 0 50 2 20 70 28 27 24 0 89 2 3 5 15 20 20 28 10 77 4 0 4 3 0 1 10 70 0 1 0 | 0 50 5 0 1 0 c) The storage discharge relationship for this catchment was calibrated as S = 1200 Q where S is in m³ and Q in m³/s. Estimate the peak discharge from the catchment for the storm event in (b). [8 marks] 1 5 P1 2 P3