In the design of agricultural subsurface pipe drainage systems, the Drainage Coefficient ($DC$) is defined as the:
Options:
(A) Depth of water removed from the drainage area in 24 hours ($1\text{ day}$)
(B) Ratio of pipe diameter to drain trench width
(C) Percentage of applied irrigation water lost as deep percolation
(D) Velocity of flow inside the tile pipe under gravity
Answer Key:
A
Step-by-Step Solution & Explanation
The drainage coefficient ($DC$) is the design drainage removal capacity expressed as the depth of water in millimeters (or inches) drained from the catchment area in 24 hours ($\text{mm/day}$). It is the fundamental parameter sizing lateral and collector drain capacities. Option A is correct.