Runoff Rate (\( q = 0.0028 \times C \times I \times A \)):

Where:

• \( q \) is the design peak runoff rate, in cubic meters per second (m³/sec).
• \( C \) is the runoff coefficient.
• \( I \) is the rainfall intensity in mm/hour for the design return period and for a duration equal to the “time of concentration” of the watershed.
• \( A \) is the watershed area, in hectares (ha).