Example:
Estimate runoff using the Rational Method in the following example with the given information provided below:
Location: Seoul, Korea
Surface composition and cover:
GMd soil with average turf
47.9 acres
Compacted gravel surface
0.9 acres
NOTE: Information on delineation areas and subareas will be provided for this example. Usually the information
would be obtained from a topographic map of the area.
Solution:
STEPS 1, 2, and 3 are given.
STEP 4. Classify the basin as simple or complex.
Since GMd soil makes up greater than 80 percent of the total area, the basin is classified as a simple area. This
basically means that the entire area will be represented with one "C" value.
STEP 5. Determine representative flow paths. For this example we will use figure 2-3.
Figure 2-3. Delineated basin
2-9
EN5465
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