A watershed with an area of 230 km² is under further development during a 10-year horizon. After finishing the development project, the percentage of imperviousness, watershed storage, and basin development factor will change from 25, 4, and 3 to 45, 6, and 9, respectively. Evaluate the effect of the urbanization on the peak discharge of this watershed.

Assume that the average slope of watershed is 0. 02 m/m. The IDF curve of Problem 3 could be applied in this watershed. The peak discharges from different return periods before urbanization are given in Table 12. 17.

Transcribed Image Text:

TABLE 12.17 Estimated Peak Discharges for Watershed of Problem 16 in Different Urbanization Conditions Return Period (year) 2 25 5 10 25 50 100 500 Rural Peaks (m/s) 32.5 49.8 67.3 86.1 104.8 150.3 210.2