curve number, which along with longest flow path and slope, is used to calculate the lag time of the watershed.
Figure 3.1: Watershed Parameters
CASE I: TRADITIONAL METHODS
Traditional hydrologic modeling involves calculating watershed
parameters based on a paper map. Two instruments, a planimeter and a map
wheel, aid in this process.
Traditional methods of computing terrain-based hydrologic data involve
delineating the watershed by hand using map contours as guidelines. This is a
very time consuming process, as drainage divides may be hard to locate. Pencil